Small Millet Grains: The Superfoods in Human Diet (Cereals, Pulses and Oilseeds) 9811693056, 9789811693052

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Cereals, Pulses and Oilseeds

Sarita Srivastava Editor

Small Millet Grains The Superfoods in Human Diet

Cereals, Pulses and Oilseeds Series Editor Narpinder Singh, Department of Food science & Technology, Guru Nanak Dev University, Amritsar, India

Cereals, pulses, and oilseeds contribute to a significant proportion of the world population's total protein and energy requirements. The rapid increase in global population has necessitated the need to gather detailed information about the botanical, nutritional, and processing characteristics of these crops, which would be helpful to prevent post-harvest losses and prevent potential vulnerability to food shortage. This book series will comprise titles presenting comprehensive, updated insight into the chemistry, processing technologies, and utilization of various cereals (wheat, rice, maize, barley, oats, sorghum, and millets), pulses (beans, lentils, chickpeas, cowpeas, pigeon peas, lupins, and other minor pulses) and oilseeds (Soybean, sunflower, canola, groundnut, mustard, linseed, nigella, flaxseed, coconut, and safflower). Grain and grain products are staples in the diets of cultures worldwide and have made an essential contribution to daily nutrient requirements. Their consumption is encouraged in dietary guidelines worldwide for the significant contribution these foods make to nutrient intakes. This series will be an essential addition to the Food Science program. The series publishes volumes ranging from basics such as grain properties, morphology, and breeding, to the more applied aspects such as milling, post-harvest technologies, packaging, and related areas. It includes books that provide comprehensive, updated insight into the chemistry, processing technologies, and utilization of various cereal grains like wheat, rice, maize, barley, oats, sorghum, and millets. The series also includes pseudo-cereals such as amaranth, quinoa, buckwheat. The books in this series serve as instructional material for students of food science, microbiology, biochemistry, and reference material for those working in industry and R & D labs. It is a complete information source for scientists, food product developers, and nutritionists to develop functional foods and novel cereal processing technologies.

Sarita Srivastava Editor

Small Millet Grains The Superfoods in Human Diet

Editor Sarita Srivastava Department of Foods and Nutrition Govind Ballabh Pant University of Agriculture and Technology Pantnagar, Uttarakhand, India

ISSN 2662-6845 ISSN 2662-6853 (electronic) Cereals, Pulses and Oilseeds ISBN 978-981-16-9305-2 ISBN 978-981-16-9306-9 (eBook) https://doi.org/10.1007/978-981-16-9306-9 # The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Foreword

I am delighted to write foreword for the book Small Millet Grains: The Superfoods in Human Diet. India observed the year 2018 as the National Year of Millets. Now the United Nations has declared the year 2023 as the International Year of Millets. The book is unique in itself and has many good features: 1. Complete scientific and analytical information about nutritional and therapeutic properties of small millets, their processing techniques, and incorporation of small millets in traditional and unconventional foods and baby foods have been given in this book so that a scientist, researcher, and consumer are benefitted. 2. The book describes how various popular junk foods can be made into nutritious functional foods by incorporating small millets without compromising with taste. 3. Special foods have been designed for patients suffering from various diseases such as obesity, diabetes, cardiovascular diseases, and celiac disease.

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This book will be a motivating factor for promotion of small millets at production as well as consumption level. I appreciate Dr. Sarita Srivastava, Professor and Head, Department of Foods and Nutrition, for her efforts to author the book.

G.B. Pant University of Agriculture & Technology Pantnagar, Uttarakhand, India

Tej Partap

Foreword

Small millets have been staple food grains in our traditional diet. Our history reveals that small millets have been the oldest food known to mankind. Mention of these grains is found in Yajurveda. It is said that history repeats itself. The time has come now to realize the importance of small millets in the diet and these grains are being labelled as “super food” or “powerhouse of nutrients.” In view of the tremendous agricultural and nutritional potential, Food and Agriculture Organization (FAO) has declared the year 2023 as International Year of Millets. I am very happy that this book describes how to use small millets in daily diet and how to be benefitted through the use of small millets in boosting immunity and preventing various diseases such as diabetes, heart disease, obesity, and celiac disease. I am sure that this book would be an asset to support government policies for promotion of use of small millets in human diet.

Government of Uttarakhand Dehradun, Uttarakhand, India

Satpal Maharaj

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Foreword

Millets are grains that are a treasure trove of health-promoting qualities. To ensure nutritional security in the vulnerable regions, millets are a strong contender to be included as staple food, as they possess better nutritional qualities compared to other cereals. They fit the current biggest global health food trends like “gluten free,” “super food,” “ancient grain,” “low glycemic index,” and “good for losing weight” and it is important to capitalize on these trends to ramp up the demand. Besides the health benefits, it is a highly sustainable and drought-resistant crop that are grown in areas with low rainfall and infertile soil. They are good for holding water, unlike wheat and rice, and add a lot of organic matter for soil health revival. Millets have shorter cultivation cycles and are less cost-intensive. These unique features make millets suited for and resilient to India's varied agroclimatic conditions, making them a sustainable strategy for addressing climate change and building resilient agri-food systems. The book describes the pathways for improving agribusinesses within the Indian small millets value chain, because of the impact that they can have in improving livelihood, and the environment and health of the Indian population. I envisage that the book will be helpful in promoting the use of small millets in the diet of people. The analyses carried out in this book indicated that a potentially larger market exists for small millets in India. Perception regarding millets is beginning to change and they are returning to farms and fields. I hope that the findings of this study will be of immense use to policymakers and other stakeholders to bring colossal problems of nutritional security to forefront and provide solutions to tackle them. I appreciate the authors for choosing an area which is so vital in the present context of food and nutrition security.

National Institution for Transforming India, NITI Aayog New Delhi, India

Amitabh Kant

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Preface

Presently with 821 million people in the world suffering from hunger, one in three malnourished, achieving sustainable development goal of zero hunger by 2030 seems to be far-fetched reality, despite large efforts at various levels. The situation is grave for Asia, where nearly half a billion (63% of world’s hungry) people are hungry. The vulnerable segments like children under five, women especially pregnant and lactating, and adolescent girls are more susceptible to malnourishment characterized by underweight, stunting, wasting, anemia, etc. Food and nutrition security plays a crucial role in combating malnutrition in any region. Small millets are the most neglected crops which have good potential for accomplishing food and nutrition security. Small millets are hardy and climate resilient crops most suitable to semi-arid region. They are known to be nutritious crops bestowed with nutraceutical properties making them excellent functional food. All small millets are good source of micronutrients viz. minerals and vitamins. These micronutrients have specific role in making immune system strong and preventing infection. They play an important role in scavenging toxins produced in large quantities in the body during infection and also increase the probiotic bacteria in the intestine. Phytochemicals present in small millets, especially antioxidants prevent oxidative stress in the body. They aid in prevention of several diseases, for example, cancer, cardiovascular disease, metabolic syndrome, and diabetes. Phytochemicals enhance both native and adaptive immune function and prevent infection. The presence of dietary fiber and resistant starch in small millets makes the incorporated food product low GI, thus helps in prevention of diabetes, cardiovascular disease, obesity, and cancer. Low GI food helps in weight reduction and in turn immunity system’s strength is regained. Small millets are also rich source of protein, especially in comparison to other staple food such as rice. Intake of rice as staple food in the diet increases blood sugar which in turn weakens the function of immune cells. In India, the main source of protein in diet are cereals rather than pulses. Though pulses contain 20–25% protein but intake of cereals in the diet is nearly 8–10 times than intake of pulses. Substitution of wheat and rice in the diet by small millets will provide not only sufficient quantity of protein but will also impart other health benefits such as strong immunity which would be helpful in preventing communicable diseases caused by pathogens xi

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and also non-communicable diseases. Thus, small millets can be effectively used for the development of various regular and therapeutic foods, after suitable processing. Owing to the potential of small millets, India observed the year 2018 as the National Year of Millets. The year 2023 has been declared as the International Year of Millets by United Nations. This book talks about how the potential of small millets can be tapped and explored to develop functional and conventional food products with improved nutritional value. In the present time of population explosion accompanied with occurrence of many diet-related diseases, small millets can be boon for both producers and consumers. The book scientifically endorses that small millets which have always been neglected and underutilized have the potential to take front place in grain’s family. As of today in India, use of small millets is occasional and is limited to some rural areas where these are grown and consumed that too in the form of items like chapati or cooked as rice, kheer and halwa, etc. Availability of small millet food products in the market is also negligible and is limited to some part of urban area only. Reasons for poor utilization of small millets are many, the most important being difficult processing and characteristic flavor associated with small millets. Common people go after taste and not for nutrition. Recently, research have been taken up on small millets but these are scattered. Therefore, with the aim to utilize small millets in daily diet, and also for commercialization of small millets incorporated food products, giving emphasis on nutritive value as well sensory quality, research were taken up by editor of this book since last 35 years. The research experience on small millets and knowledge of the subject has been put down in the form of book so that all the information on small millets for their use in daily diet is available at one place. The aim of writing this book is to bring dietary change by replacing wheat and rice partly and gradually by small millets so that malnutrition declines and health of all improves. In the present and past also, several diseases originated from animals have caused threat to the existence of humankind. The small millet food products have potential to provide consumers with reliable and sustainable sources of macro- and micronutrients and phytochemicals. Therefore, the book is coming at the appropriate time when the world is struggling to feed all and probing for an answer to treat and prevent diet-related health issues. The step-by-step journey of small millets from farm to plate of consumer has been described in this book. The proposed book comprises eight chapters—overview of small millets, nutritional quality, processing techniques and its impact on phytochemicals, development of small millets-based food products, formulation of functional foods, baby food and lastly, role of small millets in attaining food and nutrition security. The first chapter introduces audience to the world of small millets. The chapter gives an overview of small millets. The second chapter “Nutritional Profile of Small Millets” deals with the nutritional composition of small millets. It also talks of the phytonutrients which

Preface

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make it functional food. Small millets are the wonder grains or treasure of health having excellent nutritional as well as therapeutic properties. The third chapter “Processing of Small Millets” focuses on processing techniques for making small millets edible. One of the reasons for disappearance of small millets from our kitchen was difficulties in processing. The chapter explains various techniques that can be adopted for processing of small millets. The fourth chapter is “Effect of Processing on Antioxidant Potential and Antinutritional Factors in Small Millets.” Antioxidants play a major role in the development of functional food. Antioxidants act as scavenger of free radicals for the prevention of degenerative diseases. Antinutritional factors on the other hand hinder the bioavailability of nutrients. The fifth chapter “Small Millets Based Traditional and Unconventional Food Products” documents the foods traditionally made from small millets and also gives details of innovative ways to incorporate small millets to develop novel food products along with the modification of traditional food products. The change in lifestyle has increased the incidence of degenerative diseases and has reduced immunity. The solution lies in consumption of functional foods. The sixth chapter “Small Millets Functional Foods” discusses the quintessential role of small millets in prevention and treatment of diabetes, cardiovascular diseases, obesity, cancer, and celiac disease. The seventh chapter “Small Millets Based Baby Food” advocates the role of small millets in combating malnutrition among young children. Appropriate processing technique and judicious combination of millets with other ingredients make small millet an excellent baby food. The last and eighth chapter “Small Millets: Path to Food and Nutrition Security” talks about the significant role of small millets in attaining food and nutrition security. Small millets are climate resilient crops and are perfect answer to feed the ever-growing population. They also have the potential to cater the nutritional requirement of the growing population. The chapters in the book have been authored by persons from different institutions who have done research on small millets and have sound knowledge of the subject. I express my heartfelt thanks to their sincere efforts and cooperation in preparation of this manuscript. Pantnagar, Uttarakhand, India

Sarita Srivastava

Contents

1

Small Millets: An Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Anju Bisht, Shweta Joshi, and Shivli Srivastava

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2

Nutritional Profile of Small Millets . . . . . . . . . . . . . . . . . . . . . . . . . . Chhavi Arya and Anju Bisht

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3

Processing of Small Millets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Anju Bisht

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Effect of Processing on Antioxidant Potential and Antinutritional Factors in Small Millets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chhavi Arya

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Small-Millet-Based Traditional and Unconventional Food Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Anju Bisht

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Small Millets Functional Foods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 Anju Bisht and Sarita Srivastava

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Small-Millet-Based Baby Food . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 Anju Bisht

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Small Millets: Path to Food and Nutrition Security . . . . . . . . . . . . . . 161 Chhavi Arya and Anju Bisht

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About the Editor

Sarita Srivastava is Professor and former Head of the Department of Food and Nutrition, College of Home Science at G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India. She has 38 years of teaching, research, and administrative experience. Dr. Sarita did M.Sc. in Food and Nutrition and Ph.D. in Biochemistry from G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India, and Post Doctorate from Braunschweig, Germany (1988–1989). She was recipient of FAO fellowship and worked under UNDP project at Michigan State University, USA, in 1993. She has worked extensively on nutritional quality of millets and product development for diversified uses including food products for diabetics and celiac disease patients. In this area, she has guided 45 M.Sc. and Ph.D. students. Ninety research papers, reviews, and book chapters are to her credit. Six patents have been filed by her. Prof. Sarita received several awards for excellence and appreciation of professional work. She received Best Teacher Award from G.B. Pant University of Agriculture and Technology, Pantnagar, 2002. She served as expert in various national forums and international conferences.

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Small Millets: An Overview Anju Bisht, Shweta Joshi, and Shivli Srivastava

Abstract

Despite the fact that small millets are nutritionally superior to refined cereals, they have received less attention. Millets are among the oldest food cultivated by human kind. These are classified as major millets and minor/small millets, depending on the grain size. They are capable of sustaining adverse agro-climatic conditions, thus are low input crops as compared to other cereals. In addition, various research studies have made it evident that small millets are superior in most of the nutritional components as compared to widely consumed cereals like wheat and rice. They play an important role in ensuring nutritional security if consumed on regular basis due to their contribution in providing a well-balanced diet. They also play an important role in economy and food security of developing countries in Asian and African continents. Despite the role of small millets in attaining food and nutritional security, their production and cultivation has registered a sharp decline. Inadequate policy support as compared to cereals like wheat and rice, poorly developed markets, and low technology application especially in developing countries are the major constraints. The investments on product development and processing units are inadequate. Unawareness about the poor nutritional quality of existing dietary patterns and resistance towards changing the prevailing dietary habits are also big issues related to the low production and consumption of small millets. With decline in the cultivation of small millets,

A. Bisht (*) Department of Home Science, MB Government PG College, Nainital, Uttarakhand, India S. Joshi Department of Foods and Nutrition, College of Home Science, GB Pant University of Agric. & Tech, Pantnagar, Uttarakhand, India S. Srivastava Nestle R & D, Manesar, Haryana, India # The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Srivastava (ed.), Small Millet Grains, Cereals, Pulses and Oilseeds, https://doi.org/10.1007/978-981-16-9306-9_1

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their availability in the market has reduced resulting in consumption of cereals that are easily available and also at lower price. But recently small millets have started gaining importance due to their preventive role in lifestyle diseases such as diabetes, cardiovascular diseases, and obesity as well as in maintaining good health. People are becoming aware of the fact that a well-balanced diet is core to good health. Corona pandemic has further made people realise the importance of healthy diet. Small millets being rich source of antioxidants and phytochemicals are considered as nutraceuticals which can play an important role in boosting immunity if consumed on regular basis. Keywords

Small millets · Production · Nutrition and health importance · Food and nutrition security · Storage

1.1

Introduction

The term millet is used to describe small-grained cereals. Based on the grain size, millets have been classified as major millets and minor or small millets. The major millets include sorghum and pearl millet, while small millets include finger millet, foxtail millet, kodo millet, proso millet, barnyard millet, and little millet (www. millets.wordpress.com). Minor millets or small millets as opposed to major millets are cultivated for their small grains which are borne on short, slender grassy plants. In other words, they refer to a group of small-seeded cereal crops (NAAS 2013). Millets are small-seeded grasses with short growing season and they grow well under marginal conditions of soil fertility and moisture. Millets are well adapted to thrive under various agro-climatic conditions. Table 1.1 and Fig 1.1 gives a glimpse of small millets.

1.2

History of Small Millets

Millet is referred to as an ancient grain. Its cultivation is estimated to begin in the Korean Peninsula before 3000 B.C. (Crawford and Lee 2003). Since then, the production and consumption of millets spread throughout western and southern parts of Africa and also in East Asian nations (Crawford 2006). According to Lu et al. (2009), millets have been important food staples in human history, particularly in Asia and Africa. In East Asia, millets have been cultivated since last 14,000 years. According to Michaelraj and Shanmugam (2013), the oldest food known to mankind which is used as domestic purpose are millets. Among various small millets known, foxtail millet is first used for domestic purpose. The history of small millets is so old that its mention is also found in Yajurveda, indicating that its consumption is common during the ancient period. The mention of finger millet, foxtail millet, and barnyard millet in Yajurveda are identified as shyaamaka, priyangava, and

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Table 1.1 Small millets with botanical and local names S. No. 1 2 3 4 5 6 7 8 a b

Small millets Finger millet Proso millet Foxtail millet Little millet Barnyard millet Kodo millet Teff millet Fonio millet White fonio Black fonio

Botanical name Eleusine coracana Panicum miliaceum Setaria italica Panicum sumatrense Echinochloa frumentacea Paspalum scrobiculatum Eragrostis tef Digitaria exilis Digitaria iburua

Local name Mandua, nachni, ragi, marwa, bavato, Mandia, kezhvaragu, ragulu Barri, panivaragu, Varigalu, baragu Thinai, Kangni, korra, navane, Thina, Syama dhan Samai, kutki, sama, same, chama Jhangora, Kuthiravali, odalu, Madira, sanwa, shamula, sawank Varagu, kodra, arikelu, Harka – Findi (in Africa)

aanava, respectively, which indicates that the consumption of small millets was common since that period. The domestic use of small millets was also found during the Indian Bronze age, predating 5000 years ago (Yang 2005). The use of small millets has not only been found in India but also in the diet of Mumun society of Korea and Neolithic societies of China. According to Tarannum (2006), cultivation of small millets was of greater prehistory than rice, especially in northern China and Korea.

1.3

Worldwide Production and Distribution of Small Millets

Globally, the market of millets is segmented by geography, i.e. Europe, North America, South America, Asia-Pacific, and Africa. Worldwide, the largest producers of small millets are India, China, and Africa, which accounts for more than 55% of global production. Production of small millets has declined despite their climate resiliency and superior nutritional quality. According to FAO and ICRISAT estimates, in 1992–1994, 94% of total global output (28 million ton) was seen in Asian and African countries, with highest production for pearl millet (more than 50%), followed by foxtail millet, proso millet, and finger millet. However, this production was stable since 1989–1991 with no change in area under production and yield (Kajuna 2001). The recent global trends can be seen in Table 1.2 for the area harvested, production, and yield of millets further witnessing a decline in production

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FINGER MILLET

BARNYARD MILLET

FOXTAIL MILLET

LITTLE MILLET

PROSO MILLET

KODO MILLET

Fig. 1.1 Small millet grains Table 1.2 Worldwide trends in area under cultivation, production, and yield of millets Year Area harvested (MH) Production (MT) Yield (kg/ha)

2011 10.68 12.66 1185.4

2012 10.75 10.75 999.8

2013 9.17 10.91 1188.6

2014 9.68 11.42 1178.9

2015 9.11 11.63 1275.8

2016 8.84 10.28 1162.9

Source: Debabandya and Muzaffar (2019), United States Dept. of Agriculture USDA (2017)

of millets in the last decade. A shrinkage in the area under millet production from 10.68 million hectare in 2011 to 8.84 million hectare in 2016 is observed. Simultaneously, the production has reduced from 12.66 MT in 2011 to 10.28 MT in 2016. According to Research and Markets (2019), the global millet production is more than 27.8 million ton, out of which India has the largest market share of 41.04%. India, Niger, and China together account for 55% of global production. On the other hand, the consumption of small millets has also decreased at the rate of 0.9% globally; however a positive movement is being expected in 2019–2024. African countries like Mali, Sudan, and Nigeria represent higher percentage of millet consumption in global market. More than 40% of global millet consumption is utilised by these African countries. The millet production area has risen in African countries

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in contrast to other countries where the production and cultivation have declined in recent years. The decline in small millet production and distribution has been mostly observed in Asian countries, which are mainly influenced by policy changes in China (www.fao.org). Small millets are grown as subsistence crops for local consumption in most parts of the world. The major constraints related to declined production of small millets is attributed or reinforced by poorly developed markets and low technology application especially in developing countries (Khoury et al. 2014). Another constraint related to decline production of small millets is inadequate policy support as compared to cereals like rice and wheat. High prices and its inadequate availability in local markets is another big constraint. The COVID -19 pandemic has further influenced the situation of food supply system globally. The COVID-19 situation has affected the market both negatively and positively. The negative sides include disruption in supply chain, shortage of labour, and shutting down of small processing units due to repeated lockdowns. But counting the positive side, there was a significant increase in retail sale. The reason behind is the change in the food choices and habits of people, opting healthy food and superfoods alike millets with the purpose of boosting immunity. It is expected that the demand of millets will increase due to consumers demand towards having healthy foods (www.mordorintelligence.com).

1.4

Production and Consumption of Millets in India

Millets considered as poor man’s food is the staple diet for majority of population in Asian and African continent, but unfortunately it lost its importance in the past decades. Not much effort was seen in expansion of area under millet cultivation and millet cropping system. India which is the leading producer of millets in the world also witnessed shrinkage in area under millet cultivation. It dropped from 17.84 m ha in 1979–1981 to 13.95 m ha in 1992–1994, although an increase in yield and production were observed. According to FAO estimates, India is the world’s largest producer of millets, accounting for 40% of world’s production, followed by China. It has also been reported that over past 30 years, millet food consumption was stable globally, but consumption of all other cereals doubled (www.fao.org), indicating negligence of millets. Almost half a century before, millets were the most commonly grown crops accounting for 40% of cultivated grains which was higher than refined cereals like rice and wheat. However, the share of millets in total production declined from 40% to 20% (ICRISAT 2017). A decline from 22.17% to 6.94% from 1950–1951 to 2011–2012 was seen in share of millets in total food grain production (Malathi et al. 2016). Anbukkani et al. (2017) analysed the NSSO data and reported a drastic decline in area under small millets and finger millet from 1955–1956 to 2013–2014. An eight times decrease in area and four times decrease in production of small millets were observed in these five decades. Malathi et al. (2016) also studied the primary data obtained from Directorate of Economics and Statistics, Government of India, and observed the similar trend from 1950–1951 to 2011–2012

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Table 1.3 Status of average area, production, and yield of millets in India from 1950–1951 to 2011–2012

Crop Finger millet *small millets **Total millets

Average area (1000 ha) 1951–1952 2011–2012 2211.7 1326.87

Average production (1000 t) 1951–1952 2011–2012 1359.3 2003.73

Average yield (kg/ha) 1951–1952 2011–2012 615 1510

4804.3

847.43

1863.7

521

388

615

31,966

18376.17

11,633

18079.1

364

984

Source: Malathi et al. (2016) Small millets include foxtail millet, little millet, kodo millet, proso, and barnyard millet (excluding finger millet) b Total millets include sorghum, pearl millet, finger millet, and small millets a

shown in Table 1.3. The production affected the consumption levels also. Table 1.4 shows the fall and rise of area harvested (1000HA), production (1000MT), and domestic consumption of millets in India since the last seven decades (IndexMundi 2021). However, now the attempts are being made to popularise millets. Owing to their nutritional and eco-friendly importance, it is being tried to revive millets as a promising food source for future. Attention is being given on increasing production of millets as it is recognised that millets are crucial for sustainable development. They need very low agricultural inputs like water as compared to rice and wheat and may be an efficient tool in battling against threat of water depletion. Water scarcity is something which the whole world will face in the coming future. Presently, India is leading in millet production and domestic consumption in the world, followed by Niger and China. Area harvested under millets is also highest for India, followed by Niger and Sudan; however the yield is highest for China (3MT/HA), followed by Ethiopia (IndexMundi 2021). Also, because of their nutritional and therapeutic importance, consumption of millets is increasing in urban populace. Millet-based products are finding their way in food basket of health-conscious segment. It was seen that increase in demand of fibrous food as breakfast meal led to more than 20% revenue generation for millets market in 2018. Seeing the popularity of millets, India has gained more than 45% of global share in millets market, and it is expected that millets market growth will rise from $9 billion in 2019 to $12 billion by 2025 (www. agriexchange.apeda.gov.in). Presently, small millets are cultivated in eleven states in India, with maximum area cultivated in Madhya Pradesh, followed by Chhattisgarh, Maharashtra, and Uttarakhand, whereas production is highest in Madhya Pradesh, followed by Uttarakhand, Maharashtra, and Gujarat. The total area under small millets cultivation in India is 6.19 lakh hectares with total production of 4.41 lakh hectares (Gowri and Shivakumar 2020).

Source: IndexMundi (2021)

Year Area harvested (1000HA) Production (1000MT) Domestic consumption (1000MT)

1960 18,939 7087 7087

1970 20,168 12,172 13,672

1980 17,866 9461 9361

1990 15,095 10,424 10,324

2000 13,012 10,078 10,100

2010 11,698 13,005 12,500

2020 8800 12,500 12,500

Table 1.4 Fall and rise of area harvested (1000HA), production (1000MT), and domestic consumption of millets in India from 1960 to 2021 2021 8900 12,000 12,200

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Nutritional and Health Importance of Millets

Millets have been incorporated into early farming system but are generally ignored and seen as a minor grain crop playing a secondary role in the agriculture as compared to cereal grains like wheat and rice (Weber and Fuller 2008), but as food, they are nutritionally equivalent or superior to most cereals. Millets are consumed in most of the developing countries. In India, uses are limited due to very low availability of milling technology and variety of products at commercial scale. Uses of small millets are primarily restricted to animal feed in developed countries (www.millets.squapl.com). Small millets are rich sources of nutrients like protein containing high levels of methionine, cystine, and other vital amino acids for human health, micronutrients like minerals (zinc, iron, copper, calcium), and B-complex vitamins, viz. thiamine, riboflavin, folic acid, and niacin. The protein, fat, and carbohydrate contents of small millets range between 8% and 12%, 2% and 5%, and 60% and 75%, respectively. The dietary fibre content of small millets ranges from 15% to 20%, which plays a major role in various lifestyle diseases. The essential amino acid profiles of the small millets protein are better than maize, whereas the protein present in finger millet is unique due to the sulphur-rich amino acid content. Like cereals, small millets are also poor source of lysine, but when combined with lysine-rich pulses and legumes, the protein profiles of both pulses (lack methionine) and millets (rich in methionine) complement each other making them nutritionally balance food with high biological value (Gopalan et al. 2007). Nutritionally small millets are richer compared to fine cereals. They are rich sources of calcium; finger millet is an example which contains a considerably high amount of calcium that ranges from 300 to 350 mg/100 g and other minerals like iron and phosphorus. They contain a high amount of lecithin which is considered excellent for strengthening the nervous system (Dayakar Rao et al. 2016). Small millets are not only comparable to major cereals with respect to their nutritional features but are very good sources of phytochemicals having nutraceutical properties. They are rich sources of dietary fibre—a non-nutrient content which possesses various therapeutic properties providing many health benefits like improvement in gut health and reduction in high blood cholesterol and glucose levels. According to Saleh et al. (2013), lower incidence of diabetes has been reported in millet-consuming populations. Millets release lesser percentage of glucose over a longer period of time, whereas polished rice causes rapid and higher spike in blood glucose level after its consumption. This property of small millets makes it a low GI food, which is central to management of all metabolic disorders. Apart from dietary fibre, small millets are also rich sources of various phytochemicals having health-promoting effect like phytosterols, polyphenols, phytocyanin lignans, phytoestrogens, etc. The mechanism of action is due to their antioxidant activity and they also work in the body by their immune-modulating effects. They act as major sources of detoxifying agents in the body and hence protect against various degenerative diseases (Rao et al. 2011). The high dietary fibre content and the presence of antioxidants in millet-based diets not only show

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excellent improvement in cardiovascular diseases and diabetes but also prove beneficial in cancer and obesity. Besides their vital role in the management of degenerative diseases, small millets are of utmost importance in the diet of patients with gluten sensitivity or celiac disease. Small millets are non-glutinous and nonacid-forming foods and therefore are soothing and easy to digest (Michaelraj and Shanmugam 2013). Small millets are staple food substitute for patients with celiac who require gluten-free cereal (Shahidi and Chandrasekara 2013).

1.6

Constraints and Strategies in Improving Production and Consumption of Small Millets

Despite the multiple advantages, small millets also termed as superfood face challenges at production as well as consumption level. Small size and hard outer surface increase the drudgery of the farmer especially women in processing of small millets. Unavailability of machines designed specifically for processing of small millets forces the women to process the small millets manually which is time and energy consuming. Lack of local market to sell their produce is another reason for adopting indifferent attitude towards millets by the producers. At consumption level, lack of variety and unavailability of small millet-based food products, high price of the limited products available, cheap availability of refined cereals such as rice and wheat through public distribution system, and ignorance considering millets as food for poor and animals are some of the reasons of neglecting small millets at consumer level. Lack of government initiatives to prioritise small millets further leads to the development of negative perception by producers as well as consumers towards small millets. However, in recent past, the importance of small millets has been recognised by producers, consumers and policy makers. Promotion of sustainable agricultural practices is being done which is helping in increasing production, such as plant population management, breeding strategies, promotion of varietal improvement and mixed farming system, availability of quality seeds, introduction of low-cost implement, use of dehuller and improved harvester, development of local processing infrastructure, and post-harvest infrastructure and market. Creating awareness among masses to consume healthy small millet-based products, developing low-cost value-added products, improving the availability of small millet-based products in local market, and making small millets part of welfare scheme related to attainment of food security are few strategies adopted to promote the consumption of small millets. Besides these, the government is also focussing on strengthening research institutes working in the fields of small millets improvisation (RESMISA Project 2014; Meena and Meena 2018).

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Small Millets for Food and Nutritional Security

Apart from being nutritious, millets share a set of characteristics which make them unique among staple crops. With an ever increase in world population, the need to feed a balanced and nutritious diet to all has also increased, thereby getting rid of hunger and malnutrition along with emphasising on sustainable development. Small millets are an excellent example of climate resilient C4 crops. They are drought, temperature, and pest tolerance. They are capable of withstanding dry conditions, can cope with relatively poor soils, and require few external inputs. Fearing the climate change challenges in the near future, small millets can serve as an excellent eco-friendly substitute to other refined cereals. They are fast-growing crops which would provide crop yield in shorter span of time, thus meeting the needs of growing population faster and mitigating food insecurity. Small millets also make strong economic sense as they are used as dual-purpose crops, i.e. food as well as fodder in mixed farming systems. The term nutrition security not only implies to availability and access to balanced diet at affordable cost but also includes provision of safe environment. In this respect, millets contribute towards balanced diet as well as safe environment (Connor 2016). Programmes like Initiative for Nutritional Security through Intensive Millets Promotion (INSIMP) were started under Rashtriya Krishi Vikas Yojana by Government of India to uplift the level of millets from production to consumption. The major aim behind the initiative was to make millets easily available to the people at an affordable price and to spread awareness regarding the health benefits and high nutritional value of millets and therefore encouraging their inclusion in the diet on regular basis. Finger millet and pearl millet were covered under minimum support price under this scheme. This scheme is now merged with National Food Security Mission. National Mission on Sustainable Agriculture, Rainfed Area Development Project, and National Food Security Act are few programmes implemented to promote utilisation of millets for food and nutrition security (RESMISA Project 2014; Anbukkani et al. 2017). These underutilised crops with excellent nutritional properties are the best weapon to fight against malnutrition and are capable of making India a nutritionally secure place.

1.8

Storage of Small Millets

Storage of grains is important not only for attaining long-term food security but also for food supply round the year, for short-time hoarding at place of harvest till it reaches place of production, and for keeping grains for planting in the next season. Small millets have excellent storage properties compared to other cereals owing to their hard hull covering the endosperm and thereby protecting them against insect infestation, but they still need to be stored under ambient abiotic and biotic conditions. Seed storage conditions like relative humidity, temperature, free from pest, judicious ventilation, and vapour-proof surface and walls needs to be maintained. The type of storage facility required also depends on the amount of

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seeds to be stored and duration of storage. Millet seeds should be stored at 20
C or lower temperature and 50% relative humidity. Moisture-proof floor, wall, and ceiling should be maintained by using dehumidifying agents (ICAR-IIMR 2019). Traditionally, the small millets are stored after sun drying in structures made with locally available eco-friendly material like mud straw bins, earthen ware pots, bamboo structure, and underground storage structure made with wooden planks and thatch silo (Dhan Foundation 2011; Kajuna 2001; Mobolade et al. 2019). The small millets seeds stored under ordinary conditions can remain viable up to 3 years (ICAR 1987). However, the dehulled small millets have short shelf life (2–3 months) due to fat lipolysis and further oxidation of de-esterified unsaturated fatty acids, resulting in off flavour. Vacuum packaging, modified atmosphere packaging, and hermetic storage are solutions for their improved shelf life (www.dhan.org).

1.9

Conclusion

Millets are small-seeded grains used for food and fodder. Historical evidences show that small millets are the oldest food known to mankind. The Asian and African continent predominantly cultivated and consumed millets. However, with passage of time, these coarse grains were considered inferior to refined grains such as rice and wheat. With the green revolution, the interest of producers towards small millets declined leading to shrinkage in area under cultivation and reduction in their share in total food grain production. More importance was given to remunerative crops by the farmers. Moreover, the drudgery involved with the processing of these grains and lack of post-harvest infrastructure and local market aggravated the problem. Consumers also preferred refined grains over these grains because of the readily and cheap availability of refined grains. Consequently, small millets lost their importance in food system despite their many special attributes. Small millets are hardy crops requiring very little inputs and alleviating pressure on environment in comparison to other refined cereals. Sustainable development is the need of the hour and small millets are the apt candidate in maintaining it. They are the climateresilient crops with shorter lifespan, providing yield in lesser time. In addition, small millets are superior in nutritional quality than their refined counterparts. Small millets are rich sources of protein, vitamins, and minerals. They also contain good amount of dietary fibre and phytochemicals which impart them with therapeutic properties, and therefore they are rightly said to be nutraceuticals or superfoods. Evidences show that small millets can be excellent part of functional food thereby helpful in treating diabetes, cardiovascular diseases, cancer, obesity, and celiac diseases. Eventually, the eco-friendly small millets with high nutritional and therapeutic properties have been recognised, and efforts are being made to popularise millets both at production and consumption levels. Various initiatives are being taken to remove the constraints in cultivation and usage of small millets, so as to combat food and nutritional insecurity. Thus, there is a need to bring millets—the forgettable crop—into the mainstream for addressing various environmental, nutritional, and health issues.

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References Anbukkani P, Balaji SJ, Nithyashree ML (2017) Production and consumption of minor millets in India- a structural break analysis. Ann Agric Res New Ser 38(4):1–8 Connor AO (2016) Is teff the new super grain? https://en.wikipedia.org/wiki/Eragrostis_tef Crawford G (2006) East Asian plant domestication. In: Archaeology of Asia. Wiley, Oxford, pp 77–95 Crawford GW, Lee GA (2003) Agricultural origins in the Korean peninsula. Antiquity 77(295): 87–95 Dayakar Rao B, Bhaskarachary K, Rajendra Prasad MP, Bala KD, Dhanasri K, Nageswara Rao TG (2016) Nutritional and health benefits of millets. ICAR- Indian Institute of Millets Research, Rajendranagar, p 86 Debabandya M, Muzaffar H (2019) Millets processing: status, scope and challenges https://www. slideshare.net/MuzaffarHasan1/status-scope-and-challenges-in-millet-processing DHAN Foundation (2011) Report on survey of post-harvest technology and constraints faced by women farmers related to small millets and associated crops. https://www.dhan.org/ smallmillets/docs/report/PHT_final_report/pdf Gopalan C, Ramshashtri BV, Balasubramaniam SC (2007) Nutritive value of Indian foods. National Institute of Nutrition, ICMR, Hyderabad Gowri MU, Shivakumar KM (2020) Millet scenario in India. Econ Aff 65(3):363–370 ICAR (1987) Finger millets and other minor millets. In: Package of practices for increasing production. ICAR, New Delhi ICAR-IIMR (2019) Manuals on good agricultural practices in millets. ICAR-IIMR, Hyderabad ICRISAT (2017) Bringing back millets- the super crop of our ancestors. www.icrisat.org Index Mundi (2021). www.indexmundi.com/agriculture/?country¼in&commodity¼millet&graph Kajuna STAR (2001) Millet post harvest operations. www.fao.org/fileadmin/user_upload/inpho/ docs/Post-Harvest-Compendium Khoury CK, Bjorkman AD, Dempewolf H, Villegas JR, Guarin L (2014) Increasing homogeneity in global food supplies and the implications for food security. Proc Natl Acad Sci U S A 111(11):4001–4006 Lu H, Zhang J, Liu K-b, Wu N, Li Y, Zhou K, Ye M, Zhang T, Zhang H, Yang X, Shen L, Xu D, Li Q (2009) Earliest domestication of common millet (Panicum miliaceum) in East Asia extended to 10,000 years ago. Proc Natl Acad Sci U S A 106(18):7367–7372 Malathi B, Appaji C, Rajendra Reddy G, Dattatri K, Sudhakar N (2016) Growth pattern of millets in India. Indian J Agric Res 50(4):382–386 Meena PC, Meena PC (2018) Millets crop role in food and nutritional security in India. Int J Food Sci Nutr 3(6):216–218 Michaelraj PSJ, Shanmugam A (2013) A study on millets-based cultivation and consumption in India. Int J Mar Finan Ser Mgt R 2(4):49–58 Mobolade AJ, Bunindro N, Sahoo D, Rajashekar Y (2019) Traditional methods of food grains preservation and storage in Nigeria and India. Ann Agric Sci 64(2):196–205 NAAS (National Academy of Agricultural Sciences) (2013) Role of millets in nutritional security of India. Policy Paper 66:16 Rao BR, Nagasampige MH, Ravikiran M (2011) Evaluation of nutraceutical properties of selected small millets. J Pharm Bioallied Sci 3:277–279 Research and Markets (2019). Global millet markets 2019–2024–India dominates global production & Africa dominates global consumption RESMISA Project (2014) Small millets. Policy Briefing August 2014. www.dhan.org Saleh ASM, Zhang Q, Chen J, Shen Q (2013) Millet grains: nutritional quality and potential health benefits. Compr Rev Food Sci Food Saf 12:281–295 Shahidi F, Chandrasekara A (2013) Millet grain phenolics and their role in disease risk reduction and health promotion: a review. J Funct Foods 5(2):570–581

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Tarannum M (2006). Millets older than wheat, rice: Archaeologists. Lucknow Newsline. USDA (United States Department of Agriculture) (2017). https://apps.fas.usda.gov/psdonline/ circulars/production.pdf Weber SA, Fuller DQ (2008) Millets and their role in early agriculture. Pragdhara 18:69–90 Yang L (2005) Handbook of Chinese mythology. Oxford University Press, New York, p 198

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Nutritional Profile of Small Millets Chhavi Arya and Anju Bisht

Abstract

Small millets are highly nutritious crops and are rich source of macronutrients, micronutrients, and phytochemicals. Owing to their agrarian as well as nutritional qualities, these have the potential to provide food and nutrition security. Macronutrient profile of small millets is similar to that of major cereals like wheat and rice; however, small millets score higher in terms of micronutrients and phytochemicals. Finger millet is a source of good quality protein and has a sound amino acid profile. Among cereals and millets, it is the richest source of calcium and is also good source of iron and phosphorus. The therapeutic properties of finger millet can be attributed to its high dietary fiber and phenolic content. The protein content of foxtail millet is higher than that of widely consumed major cereals such as rice and maize. Foxtail millet and its bran is rich in polyunsaturated fatty acid (PUFA) such as linoleic acid. Foxtail millet is a good source of dietary fiber and several minerals. Antioxidants present in foxtail millet exhibit effective inhibition of free radicals action. Apart from minerals, kodo millet is a good source of dietary fiber, antioxidants, and polyphenols and can be used as a nutraceutical. Barnyard millet contains highly digestible protein. It is also a good source of dietary fiber, iron, niacin, and thiamine. Proso and little millets are rich sources of mineral, B vitamins, dietary fiber, and phytochemicals and antioxidants.

C. Arya (*) Department of Home Science, DSB Campus, Kumaun University, Nainital, Uttarakhand, India A. Bisht Department of Home Science, MB Government PG College, Nainital, Uttarakhand, India # The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Srivastava (ed.), Small Millet Grains, Cereals, Pulses and Oilseeds, https://doi.org/10.1007/978-981-16-9306-9_2

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Keywords

Small millets · Nutritious · Macronutrients · Micronutrients · Phytochemicals

2.1

Introduction

Small millets have formed an important part of the human diet since prehistoric times. In the past, millets were cultivated and consumed in almost all parts of the globe, primarily so in Asia, Africa, and Europe. Small millets have always been the versatile crops since these require very little agricultural inputs and on the other hand provide substantial output in terms of productivity of nutritious grains. Small millets are considered crops of food security because of their sustainability in adverse agroclimatic conditions (Singh et al. 2004). With changing climatic conditions, we are facing the problem of water scarcity and food insecurity. As all small millets are drought-resistant crops, these have the potential to face the challenge of water scarcity and address the problem of food insecurity. Millets are small seeded and are also known as coarse grains. Globally coarse cereals are an important part of diet of millions of people. There is growing realization of nutritional and health benefits of the underutilized millet grains, which have paved the way for the growth of millet production (Deshpande et al. 2015). On the basis of grain size, millets have been classified as major millets which include sorghum and pearl millet and several minor millets or small millets, which include finger millet (Eleusine coracana), foxtail millet (Setaria italica), kodo millet (Paspalum scrobiculatum), proso millet (Panicum milliaceum), barnyard millet (Echinocloa frumentacea), and little millet (Panicum sumatrense). In the past, millets had a greater share in the diets; therefore, these were an important source of energy, protein, micronutrients, dietary fiber, and phytochemicals (Table 2.1). Over the past decades, millets, however, lost out to Table 2.1 Proximate composition of small millets and other cereals (per 100 g edible portion) Food Wheat Rice (brown) Maize Finger millet Foxtail millet Kodo millet Barnyard millet Proso millet Little millet

Protein (g) 11.6 7.9 9.2 7.7 11.2 9.8 11.0

Fat (g) 2.0 2.7 4.6 1.5 4.0 3.6 3.9

Ash (g) 1.6 1.3 1.2 2.6 3.3 3.3 4.5

12.5 9.7

3.5 5.2

3.1 5.4

Values are on 12% moisture basis Source: Saleh et al. (2013)

Crude fiber (g) 2.0 1.0 2.8 3.6 6.7 5.2 13.6 5.2 7.6

Carbohydrate (g) 71.0 76.0 73.0 72.6 63.2 66.6 55.0

Energy (Kcal) 348 362 358 336 351 353 300

63.8 60.9

364 329

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major cereal grains such as rice, wheat, and corn in terms of area under cultivation, production, consumption, and percent share in the diet as well as consumer preference. As a result, the proportion of millet in the Indian diet declined steadily. Regional variation in millet consumption has been observed by the National Nutrition Monitoring Bureau (NNMB 2006). They observed that consumption of millet was generally higher in the states of Gujarat, Karnataka, and Maharashtra, but almost nil in the states of Kerala, Orissa West-Bengal, and Tamil Nadu where rice forms the major staple. Small millets have the ability to contribute towards solving the problem of food insecurity. The excellent nutrient profile and associated health benefits have rekindled the interest of scientists and nutritionists in millets. Owing to their nutritional profile, small millets can be judiciously utilized in formulating therapeutic foods and dietary supplements.

2.2

Nutritive Value of Small Millets

Several past researches have stated that nutritionally small millet grains are comparable to major cereals such as wheat and rice. Small millets are an important source of energy, protein, B vitamins, other micronutrients, dietary fiber, and phytochemicals (Tables 2.3 and 2.4). Hence, they are rightly termed as nutri-grains (NAAS 2013). Finger millet is an exceptionally rich source of calcium. The protein content of foxtail millet ranges from 8.98% to 14.37% (Kamatar et al. 2015) which is higher than protein present in cereals such as rice and corn. Millets are good source of soluble, insoluble, and total fiber content. Most millets have antioxidant properties and high content of phenolic compounds (Thilagavathi et al. 2015a). Millets also contain β-glucans, which are water-soluble gums. The nutrient composition of grains is affected by both environment and genetics (Chen et al. 2012). One millet species differs from the other with respect to nutrient composition. Nutrient composition may also vary within different varieties of the same millet species. Despite variations, most millets are rich source of carbohydrate, minerals, B vitamins, dietary fiber, and phytochemicals. Most of these nutrients except carbohydrate are deficient in an average Indian diet. Owing to high dietary fiber and phytochemical content of millets, their regular consumption has been associated with a number of potential health benefits such as in the prevention of diabetes mellitus and cardiovascular disease (CVD), lowering of cholesterol and blood pressure, relieving constipation, etc. (Truswell 2002; Gupta et al. 2012). The dietary fiber and resistant starch of small millets exhibit hypoglycemic and hypolipidemic effects (Pathak and Srivastava 1998). Small millet flour lacks gluten, and therefore, millet flour is an ideal ingredient for the development of gluten-free food products for patients suffering from celiac disease. The importance of millets for the formulation of multigrain and gluten-free food products has been recognized (Patel and Pisalkar 2015).

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Nutritive Value of Finger Millet

Finger millet is one among the oldest consumed millet grains. Fuller (2003) reports African origin of finger millet. In India, finger millet is also known as ragi in the southern states, mandua in Uttarakhand, nachni in Maharashtra, and umi in Bihar. Finger millet grains show wide range in color from white to yellow, rust, red, brown, and violet. The red-colored ones are usually cultivated worldwide (Shobana et al. 2013). Finger millet grains have a nutritional profile comparable and even better in terms of certain nutrients to major cereal grains in popular use. It is nutritionally superior to wheat and rice with respect to protective nutrients such as dietary fiber, calcium, and protein (Mamatha and Begum 2013). It is considered a wonder crop in the arena of nutraceuticals because of its high nutritional profile (Mirza et al. 2015). On comparing the protein content of finger millet, it is observed that it has slightly lower protein content than other cereals and millets; however, its protein content is higher than rice. Chethan and Malleshi (2007) reported that the protein present in finger millet varied from 5% to 8%. Gull et al. (2014) noted that the quantity of protein found in finger millet ranges from 6% to 8%. Mirza et al. (2015) reported that the brown genotypes of finger millet (particularly PRM-6107) had considerably good nutritional properties, and it contained 9.92% crude protein. The study concluded that with greater protein solubility and greater grain hardness, finger millet grains showed better popping quality. Chauhan and Sarita (2018) found the protein content of whole raw finger millet flour, germinated finger millet flour, and popped finger millet flour to be 6.3, 8.8, and 7.1 g/100 g, respectively. Finger millet variety VL-204 was found to be exceptionally rich in protein as it contained 15.58% protein (Singh and Srivastava 2006). Vadivoo et al. (1998) analyzed 36 genotypes of finger millet and found that the white-seeded genotypes had higher protein content than the brown-seeded type. Finger millet proteins are good source of essential amino acids (Nirgude et al. 2014). The quality of protein depends on its essential amino acid composition. Amino acid profile of finger millet has a fine proportion of essential to total amino acids. It is limited in lysine, but has sulfur-containing amino acids equal to that of milk protein (Antony et al. 1996). Finger millet is especially rich in two essential amino acids – methionine and tryptophan – along with substantial amount of other essential amino acids (Fernandez et al. 2003). The amino acid methionine present in finger millet is lacking from the diet of millions of poor (Sircar et al. 2019). The amino acids, viz., isoleucine, leucine, and phenylalanine, are also present in good amount in finger millet (Chandra et al. 2016). Finger millet contains 44.7% essential amino acids (Mbithi et al. 2000). Table 2.2. shows the essential amino acid composition of small millet including finger millet. The lipid content ranges from 1% to 2.5% in finger millet (Devi et al. 2014) and plays a major role during storage of processed foods with respect to stability. Finger millet has low fat content, but it contains high amount of polyunsaturated fatty acids (PUFAs) (Antony et al. 1996). Fernandez et al. (2003) reported that finger millet seeds contained 12 mg/g total fatty acid, 42% of which was oleic acid along with

130

160 140 130 130

120

110 120

480

290 300 300 220

270 –

290 250

190 110

150 106

200 190 220 140

230

50 60

50 63

40 110 100 60

80

310 330

430 362

290 290 310 420

280 120 150 210 180 180 133 160 180

– 150 – –

150

240 200 220 –

290

– 90

110 175

100 110 140 100

90

150 190

200 231

280 240 240 190

230

760 760

650 725

720 750 690 1040

500

410 370

360 288

240 260 400 480

300

410 350

410 388

300 330 480 430

380

Arginine Histidine Lysine Tryptophan Phenylalanine Tyrosine Methionine Cystine Threonine Leucine Isoleucine Valine 290 130 170 70 280 180 90 140 180 410 220 280

Source: Gopalan et al. (2016), FAO (1995)

Wheat (whole) Rice (raw milled) Maize, dry Pearl millet Finger millet Foxtail millet Kodo millet Barnyard millet Proso millet Little millet

Table 2.2 Essential amino acid composition (mg/g N) of millets and other cereals protein

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polyunsaturated fatty acids such as linoleic acid and α-linolenic acid. The main fatty acids present in raw finger millet are palmitic, oleic, and linoleic acids, while traces of lauric, myristic, and stearic acids were found (Wadikar et al. 2007) (Table 2.1). Finger millet contains high amount of dietary carbohydrate. Ramashia et al. (2019) stated that the values for carbohydrate found in finger millet varied from 75.0 to 83.3 g/100 g; however, Himanshu et al. (2018) noted that finger millet carbohydrate content ranged from 60 to 80 g/100 g. An investigation of physical and molecular starch characteristics of foxtail, proso, and finger millet showed that millet starch granules ranged from about 2.5–24 μm in size and were mainly polygonal with a few spherical ones (Annor et al. 2014). Finger millet starch granules were mainly found to be polygonal with more of larger size granules than smaller ones, and its total starch content was 57%, and it had high amylose/amylopectin ratio (0.54) (Verma et al. 2018). Finger millet starch had much more long amylose chain than short amylose chains compared with foxtail and proso millet. Finger millet starch had longer glucan chains between branch points (Annor et al. 2014). A high amylose/amylopectin ratio indicates low glycemic index (Dipnaik and Kokare 2017). Roopa and Premavalli (2008) found that in raw finger millet varieties, the rapidly available starch was 8.3% to 11.1%, slowly digestible starch varied from 26.4% to 35.35%, and total available starch varied from 39% to 53%, and puffing of finger millet resulted in increase in rapidly available starch and decrease in slowly digestible starch. Starch retrogradation is desirable in terms of nutritional significance. The slower enzymatic digestion of retrograded starch results in moderate release of glucose in the bloodstream (Copeland et al. 2009). Jayawardana et al. (2019) found that the resistant starch content of Sri Lankan finger millet varieties ranged from 3.75% to 4.58%. Finger millet starch can be utilized commercially by blending in tapioca starch for thickening food systems (Nelson and Shimoni 2007). Finger millet contains high amount of dietary fiber. The therapeutic benefits provided by finger millet can be attributed to a large extent to its dietary fiber content. Chethan and Malleshi (2007) reported the dietary fiber content of finger millet in the range of 15% to 20%. The seed coat of finger millet is multilayered (five layered). This is a distinct property of finger millet in comparison to other millets such as sorghum, pearl, proso, and foxtail millets (FAO 1995). This property could possibly be one of the reasons for the higher amount of dietary fiber (Shobana et al. 2013). According to Devi et al. (2014), finger millet contains 18% dietary fiber. Studies suggest that finger millet dietary fiber content is higher than that of sorghum, wheat, and rice. Dharmaraj and Malleshi (2010) reported total non-starchy polysaccharide content in native finger millet as 17.11 g/100 g in which the insoluble dietary fiber (IDF) and soluble dietary fiber (SDF) contribute 15.70 and 1.40 g/100 g, respectively. According to Bachar et al. (2013), the acid detergent fiber, neutral detergent fiber, and crude fiber content of finger millet were found to be 30.58%, 12.65%, and 4.01% of dry matter, respectively. Mirza et al. (2014) reported the crude fiber content of six finger millet genotypes differing in color (brown, golden, and white) to range from 3.6% to 4.1% with a mean of 3.82%. Many health-conscious consumers today demand low-calorie foods which are rich in dietary fiber. Dietary fiber has several health benefits such as in prevention and treatment of constipation,

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lowering serum cholesterol, reducing risk of diabetes and intestinal cancer, and stimulating beneficial microorganisms (Lattimer et al. 2010). Finger millet is a good source of various minerals such as calcium, iron, and phosphorus. It is an excellent source of calcium among cereals and millets (Table 2.3). It contains up to tenfold higher calcium content than brown rice, wheat, or maize and three times than that of milk. It is also rich in iron (Kumar et al. 2016). The mean values for minerals in finger millet such as iron, zinc, calcium, magnesium, manganese, and phosphorus were found to be 3.00, 2.79, 281.98, 166.35, 24.04, and 228.09 mg/100 g, respectively (Hiremath et al. 2018). The calcium content of white varieties is higher than brown varieties (Seetharam 2001). Calcium present in finger millet can prove to be highly useful to support growth and strengthen bones of children and maintain bone health and prevent osteoporosis in the elderly. It is a highly required mineral for pregnant and lactating women. The iron content present in finger millet is 4.62 mg/100 g (Rao et al. 2017). Singh and Srivastava (2006) recorded the iron content present in 16 varieties of finger millet to range from 3.61 to 5.42 mg/100 g. Hiremath et al. (2018) reported the iron content of finger millet species in the range of 1.09–4.65 mg per 100g. Since finger millet is a good source of iron, it can be effectively utilized in formulating recipes for vulnerable groups suffering from anemia. It is also a rich source of magnesium (408 mg/100 g) (Gull et al. 2016). As finger millet is a good source of magnesium, it can help reduce severity and frequency of asthma and migraine (Dubey and Verma 2009). The zinc and phosphorus content of 16 finger millet varieties ranged from 0.92 to 2.55 and 130 to 295 mg/100 g, respectively (Singh and Srivastava 2006). Shibairo et al. (2014) found the average zinc content of finger millet genotypes to be 16.9 mg/kg. Several anti-nutritional factors such as phytates, tannins, and phenols are also present in finger millet which are reported to decrease the bioavailability of minerals. Sripriya et al. (1997) in their study found that through germination and fermentation of finger millet phytate content can be reduced by 60% which consequently improves the bioavailability of minerals. Platel et al. (2010) reported that malting of finger millet increases the bioaccessibility of iron by more than threefold; however, it reduces the bioaccessibility of zinc and marginally increases the bioavailability of calcium and had no impact on bioaccessibility of copper. Finger millet is a useful source of B vitamins such as thiamin, riboflavin, and niacin (Table 2.4). It is a rich source of thiamine and riboflavin (Chandra et al. 2016). The thiamine, riboflavin, niacin, and total folate content of finger millet was reported as 0.37 mg/100 g, 0.17 mg/100 g, 1.34 mg/100 g, and 34.66 μg/100 g, respectively (NIN 2017). Chamoli et al. (2018) reported the thiamine, riboflavin, and niacin content to be 0.48, 0.12, and 0.30 mg/100 g, respectively. Finger millet also contains the liposoluble vitamin—tocopherols (vitamin E) (Obilana and Manyasa 2002). Dykes and Rooney (2007) noted that finger millet is a great source of several phenolic compounds which might possess health benefitting properties (Table 2.5). Finger millet contains about 0.3% to 3% polyphenols and is well known for its health benefits such as eliciting low glycemic response and being hypocholesterolemic and antiulcerative (Pradhan et al. 2010). Finger millet seed coat contains a complex

Source: Gopalan et al. (2016)

Wheat, whole Rice (raw milled) Maize Finger millet Foxtail millet Kodo millet Barnyard millet Proso millet Little millet

Calcium (mg) 41 10 10 344 31 27 20 14 17

Iron (mg) 5.3 0.7 4.1 3.9 2.8 0.5 5.0 0.8 9.3

Phosphorus (mg) 306 160 222 283 290 188 280 206 220

Magnesium (mg) 138 64 139 137 81 147 82 153 133

Table 2.3 Mineral content of small millets and other cereals (per 100 g edible portion) Potassium (mg) 284 – 286 408 250 144 – 113 129

Copper (mg) 0.68 0.07 0.41 0.47 1.40 1.60 0.60 1.60 1.00

Manganese (mg) 2.29 0.51 0.48 5.49 0.60 1.10 0.96 0.60 0.68

Zinc (mg) 2.7 1.3 2.8 2.3 2.4 0.7 3.0 1.4 3.7

22 C. Arya and A. Bisht

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Table 2.4 Vitamin content of small millets and other cereals (per 100 g edible portion) Wheat whole Rice (raw milled) Maize Finger millet Foxtail millet Kodo millet Barnyard millet Proso millet Little millet

Carotene (μg) 64 0 90 42 32 0 0 0 0

Thiamine (mg) 0.45 0.06 0.42 0.42 0.59 0.33 0.33 0.20 0.30

Riboflavin (mg) 0.17 0.06 0.01 0.19 0.11 0.09 0.10 0.18 0.09

Niacin (mg) 5.5 1.9 1.8 1.1 3.2 2.0 4.2 2.3 3.2

Source: Gopalan et al. (2016)

mixture of several phenolic compounds, belonging to different classes, ranging from lower to higher molecular weight polyphenols such as tannins and anthocyanins. These seed coat phenolics are effective noncompetitive inhibitors of carbohydratehydrolyzing enzymes. Food grade phenolic inhibitors from millet seed coat extracts are potentially safer and therefore may be the preferred alternative for inhibition of carbohydrate breakdown and control of glycemic index of food products. Free and bound phenolics were isolated from native and malted finger millet, and their antioxidant properties were evaluated by Subba Rao and Muralikrishna (2002). Protocatechuic, gallic, and caffeic acids were found to be the major free phenolic acids. Ferulic, caffeic, and coumaric acids were found to be the major bound phenolic acids. The antioxidant activity of a free phenolic acid mixture was found to be higher compared to that of bound phenolic acid mixture. The total phenolics, flavonoids, and condensed tannins in free fraction (of four finger millet varieties harvested from northern Mawali) varied from 114.43 to 179.19 mg ferulic acid equivalent/100 g, 90.24 to 202.94 mg catechin equivalent (CE)/100 g, and 31.76 to 83.59 mg CE/100 g. Twenty phenolic compounds were identified in the free fractions and 17 in the bound fractions. Dark-colored finger millet varieties had higher phenolic content and antioxidant properties compared to light-colored ones (Xiang et al. 2018).

2.2.2

Nutritive Value of Foxtail Millet

Foxtail millet (Setaria italica) is yet another nutritious small millet. It is also known as Italian millet, German millet, Chinese millet, Hungarian millet, and Siberian millet. Gouda et al. (2019) found foxtail millet grains to be spheroid in shape with a mean size of 2.78 mm. It is one of the oldest cultivated crops and is mainly grown in Asia and Africa and also to some extent in Russia and the United States. Foxtail millet grains are generally light cream in color. It is an important crop grown for food and feed in China and is a C4 crop (Charulata et al. 2013). It is an underutilized food source; however, it has a promising potential in enhancing the nutritional and

Total flavonoid content (mg catechin equivalent/ 100 g, DW) –

–

–

22.82–116.98 105
9.1 101.3
10.4

373.67
12.16

361.87
10.54

231.30–394.13 107.1
7.02a 129.5
4.95a

27.17
0.47 – – –

– – –

24.42
0.55

Phytate (mg/100 g) 35.17
0.63

65.74
2.07

67.63
1.22

Antioxidant (mg AAEAA/ 100 g) 70.82
3.07

Source: Thilagavathi et al. (2015a), Ofosu et al. (2020), Kumar and Kaur (2017), Hiremath et al. (2018) a Total phenolic content (mg ferulic acid equivalent/100 g, dry weight sample) b Condensed tannin content (mg catechin equivalent/100 g, dry weight sample)

Millet flours Kodo millet flour Little millet flour Proso millet flour Finger millet Foxtail millet Barnyard millet

Total polyphenols (mg GAE/ 100 g) 368.77
11.17

Table 2.5 Phytochemical components of native small millet flour (mg/100 g)

57.43–155.44 36.37
4.56b 59.54
4.63b

22.67
0.21

18.62
0.15

Tannin (mg TAE/ 100 g) 22.53
0.24

24 C. Arya and A. Bisht

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food security (Sharma and Niranjan 2017). Foxtail millet (Setaria italica) is an important food grain grown in the foot hills of Himalayas. Protein content of foxtail millet ranges from 11.50% to 13.29% (Huchchannanavar et al. 2019). The protein content of foxtail millet is higher than that of rice, wheat, or maize flour (Cheng and Dong 2010). There is significant difference in the protein content of different varieties. Sharma et al. (2003) reported the protein content of whole and milled grains of foxtail millet in the range of 9.62%–10.36% and 5.14%–8.93%, respectively. Crude protein of foxtail millet ranged from 11.2 to 15.0 g/100 g (Himanshu et al. 2018). The crude protein content of foxtail millet has been reported as 13.10, and its lysine and tryptophan content, 2.42 and 0.31 (g/16 g N), respectively (Chandel et al. 2014). Verma et al. (2015) in their study found that foxtail millet contained 10.29% crude protein. The average content of protein in Chinese foxtail millet landraces has been found to be 15.82% (Liu et al. 2009) (Table 2.1). Foxtail millet seeds mainly consists of proline-rich, alcohol-soluble proteins (prolamin) called setarins (Sachdev et al. 2020). Mohamed et al. (2009) in their study found that defatted foxtail millet protein concentrate of white and yellow varieties exhibited substantial amount of protein content. Foxtail millet protein concentrate were easily digested by trypsin (in vitro), and the essential amino acids in them are higher than the amounts recommended by the FAO and the WHO. The study concluded that foxtail millet protein could be used as a potential functional food ingredient in food product development. The amino acid score of foxtail millet protein concentrate has been found to be 28, its protein digestibility 90%, and its NPU 37%. Lysine has been reported as a limiting amino acid in this millet protein concentrate (Kasaoka et al. 1999) (Table 2.2). Foxtail millet protein or its hydrolysate has demonstrated many bioactive effects which can be investigated for their effectiveness in the management of chronic disease in humans. Foxtail millet protein concentrates are good candidates for replacing animal food protein and possess the potential for developing low-cost functional food products (Sachdev et al. 2020). The ingestion of foxtail millet protein hydrolysates in rats was found to ameliorate hypertension and related cardiovascular diseases (Chen et al. 2017). Hou et al. (2018) included 45 subjects with untreated mild hypertension in their study and fed them 50 g of whole foxtail millet as staple food. After the study duration of 12 weeks, a significant improvement in subject’s blood pressure was observed which confirmed antihypertension effect of foxtail millet and its positive role in alleviating related cardiovascular disease. Besides, the subject’s fasting blood glucose improved, and the BMI, body fat percentage, and fat mass decreased significantly. Results clearly indicated whole foxtail millet to be a potential source of nutraceuticals and functional foods. The fat content of foxtail millet is higher than that of wheat and rice but similar to that of maize (Cheng and Dong 2010) (Table 2.1). Kamatar et al. (2015) analyzed 75 diverse germplasm lines of foxtail millet and observed considerable variation in fat percent which ranged from 2.79 to 4.16 with a mean value of 3.52. Huchchannanavar et al. (2019) analyzed the nutritional properties of 9 foxtail millet varieties and reported their fat content to range from 2.80 to 3.83 g/100 g. In a study by Kim et al. (2010) on 32 South Korean foxtail millet varieties, significant

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variability in the fatty acid content has been observed. Palmitic acid ranged from 10.9% to 13.5%, stearic acid from 2.5% to 8.3%, oleic from 10.0% to 15.8%, linoleic from 62.5% to 67.9%, and linolenic from 3.0% to 5.2%. The main unsaturated fatty acid present in foxtail millet was linoleic acid, and the most abundant saturated fatty acid was palmitic acid (Mikulajova et al. 2017). Liang (2010) studied the chemical characteristics of a sample of foxtail millet bran and reported that millet bran oil is rich in linoleic acid (66.5%) and oleic acid (13.0%). Fat content of unprocessed foxtail millet has been observed to be 4.3 g/100 g which reduced to 3.2 g/100 g on malting (Laxmi et al. 2015). Oil extract of the bran of foxtail millet contains plentiful unsaturated fatty acids of which linoleic acid (65–69%) and oleic acid (12–17%) constituted more than 80% of the lipids. Foxtail millet oil was found to be relatively abundant in potentially valuable compounds such as tocols, sterols, γ-oryzanol, and squalene (Ji et al. 2019). Himanshu et al. (2018) reported the carbohydrate content of foxtail millet to range from 59% to 70%. The mean carbohydrate content of foxtail millet has been found to be 71.58 g/100 g (Shankaramurthy and Somannavar 2019). The starch content of foxtail millet ranged from 67.5% to 68.7%, and the amylose content ranged from 3.3% to 11.4% (Kim et al. 2009). Foxtail millet starch granules from 8 Chinese varieties have been found to be polygonal, and their amylose content ranged from 16.8% to 26.8%. The starches from these varieties show similar amylopectin fine structure but differ in amylose content. Amylopectin fine structure determines starch functional properties (Qi et al. 2020). Foxtail millet grains contain 60%–70% starch on dry matter basis (Saleh et al. 2013) Foxtail millet is classified into three types based on amylose content, i.e., non-waxy, low amylose content, and waxy. The mean values of amylose content in non-waxy, low amylose, content and waxy were 12.07%, 7.21%, and 1.7%, respectively (Yin et al. 2019). The granular size of foxtail millet starches from 53 varieties ranged from 6.8 to 11.8 μm (Fujita et al. 1996). The total starch content of foxtail millet increased from 12.02% to 20.54% on fermentation by Lactobacillus paracasei (Amadou et al. 2014). Starch gelatinization was highest for roller dried foxtail millet followed by popped, flaked, and extruded products (Ushakumari et al. 2004). Starch digestibility of foxtail millet flour is lower than that of wheat flour (Ren et al. 2016). Millets are rich source of dietary fiber (Table 2.1). Anju and Sarita (2010) reported the crude fiber content of foxtail millet as 8.07% and the total dietary fiber content as 26.92%. Foxtail millet bran is a good source of dietary fiber and has good water holding capacity (3.24 g/g) and swelling power (2.06 ml/g). It also exhibits good adsorption capacities to lipophilic substances such as lard (3.34 g/g), peanut oil (2.32 g/g), and cholesterol (5.19 mg/g) and also shows bile salt adsorption capacity which indirectly reflects its cholesterol-lowering effect (Zhu et al. 2018). Foxtail millet bran dietary fiber, especially SDF, had good functional properties as its antioxidant activity has been found to be higher than IDF (based on evaluation of free radical scavenging and iron-reducing capacity in vitro). The SDF content had strong α-amylase inhibition and sodium cholate adsorption capacities (Dong et al. 2019). Whole grains exhibited 6.75%–8.83% crude fiber which lowered to 4.65%– 6.61% after milling (Sharma et al. 2003). A diabetic diet based on foxtail millet

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lowered HbA1c level (19.14%), fasting glucose level (13.5%), insulin concentrations (1.9%), total cholesterol concentrations (13.25%), triglyceride concentrations (13.51%), and VLDL concentrations by 4.5%. The diet improved glycemic control and decreased hyperinsulinemia and lowered plasma lipid concentrations in patients (Jali et al. 2012). Biscuits incorporated with foxtail millet flour show higher content of crude fiber and dietary fiber, and they also lowers glycemic index (Anju and Sarita 2010). Foxtail millet is richer in minerals, viz., calcium, phosphorus, copper, magnesium, zinc, and chromium, as compared with rice. The mean value for total minerals in foxtail millet varieties ranged from 1.08% to 1.57% (Kamatar et al. 2015). Foxtail millet showed a calcium content of 30.10 mg/100 g and iron 3.73 mg/100 g (Verma et al. 2015). Gopalan et al. (2016) reported the calcium, phosphorus, iron, potassium, copper, magnesium, zinc, and chromium contents as 31, 290, 2.8, 250, 1.40, 81, 2.4, and 0.030 mg/100 g, respectively (Table 2.3). In a study on 20 landraces and 4 cultivars of foxtail millet, a wide variation of micronutrient concentrations was found such as iron which ranged from 3.69 to 7.51 mg/100 g, zinc from 4.54 to 5.71 mg/100 g, calcium from 13.13 to 39.58 mg/100 g, potassium from 219.43 to 349.47 mg/100 g, copper from 0.60 to 1.09 mg/100 g, and manganese from 1.05 to 1.64 mg/100 g. The landraces performed better in terms of micronutrient content (Kola et al. 2020). The calcium and zinc contents of foxtail millet were 35.63 and 2.92 mg/100 g, respectively (Shankaramurthy and Somannavar 2019). Thippeswamy et al. (2017) reported that the zinc content of foxtail millet ranged from 2.29 to 11.4 mg/g and iron content ranged from 0.33 to 16.26 mg/100 g. Foxtail millet is also a potent source of antioxidants, and the yellow species of foxtail millet contain more antioxidants in comparison with the white ones (Bangoura et al. 2013). Foxtail millet contains significant level of phytochemicals and antioxidants (Sharma and Niranjan 2017). Foxtail millet showed a phenolic content of 2.5% (Rao et al. 2011). Pyrogallol, gallic acid, catechin, salicylic acid, and ferulic acid are the major phenolic compounds present in foxtail millet (Seo et al. 2011). Zhang and Liu (2015) also reported that foxtail millet varieties contained phytochemicals such as ferulic acid, chlorogenic acid, caffeic acid, syringic acid, p-coumaric acid, and carotenoids which showed antioxidant and antiproliferative activities. Foxtail millet bran oil contains vitamin E with α- and β-tocopherol as its major components (Shi et al. 2015). Carotenoids are mainly responsible for the yellow color of foxtail millet. All-trans-lutein and all-trans-zeaxanthin are the major carotenoids in foxtail millet. Carotenoids are degraded during cooking and responsible for the color change of foxtail millet (Shen et al. 2015). Lutein and zeaxanthin are the two major carotenoid components present in foxtail millet (Zhang et al. 2019). The genotypes of foxtail millet demonstrated adequate inhibition of free radicals; however, chelating activity of ferrous ions was weak. The antioxidant properties of foxtail millet are strongly related to the presence of phenolics in them. An association between the depth of the color of the grain, antioxidant quality, and phenolic compounds has been noted (Mikulajova et al. 2017). Foxtail millet is a good source of thiamine and other B complex vitamins. Kumar et al. (2018) reported

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the thiamine, niacin, and riboflavin content of foxtail millet as 0.60, 0.55, and 1.65 mg/100 g.

2.2.3

Nutritive Value of Kodo Millet

Kodo millet (Paspalum scrobiculatum) is an ancient nutritious millet grown in India, Africa, and other Asian countries. It is also known as ditch millet, rice grass, and native paspalum. Other common names of the millet include varagu, haraka, and arakalu. It is an indigenous cereal of India. Kodo millet though described as nutritious has received far less research and development attention than other crops with regard to crop improvement and utilization. It is the main source of protein and minerals in the daily diet of tribal and weaker sections (Thilagavathi et al. 2015b). Himanshu et al. (2018) reported the crude protein content of kodo millet to range from 8.0% to 10%. Yadav et al. (2013) in their study found the protein content of kodo to be 8.03 g/100 g. Kulkarni and Niak (2000) found the protein content of PSC-1 and PSC-3 (two kodo millet) varieties to be 9.92 and 9.26 g/100 g, respectively. Chandel et al. (2014) analyzed four different genotypes of kodo millet and reported the protein content to range from 6.50% to 8.44%. With respect to amino acids, the lysine content ranged from 2.19 to 2.85 g/ 16 g N, while tryptophan ranged from 0.12 to 0.31 g/16 g N. Relatively lesser variability has been observed in protein content of kodo millet genotypes. Typically, millet protein is a good source of essential amino acids especially tryptophan. The methionine content of kodo millet germplasm ranged from 72.79 to 94.43 mg/g protein, the tryptophan content varied from 25.55 to 33.27 mg/g protein, and the lysine content ranged from135.17 to 179 .17 mg/g protein (Shyam and Singh 2018) (Table 2.2). Kodo millet contains low amount of fat (Table 2.1). Deshpande et al. (2015) reported 1.4% fat in kodo millet. Yadav et al. (2013) reported 1.29% fat in kodo millet. Kulkarni and Niak (2000) found the fat content of local kodo millet cultivar to be 3.98 g/100 g. Bhat et al. (2018) reported 2.55 g/100 g fat in kodo millet. Hadimani and Malleshi (1993) reported the fat content of deglumed and milled Kodo millet as 3.8 g/100 g and 1.1 g/100 g, respectively. They further reported that 26.6% fat was present in the bran portion of the grain. Fat present in kodo millet has similar quantities of linoleic and oleic acid which make up 70% of the total fatty acid of the major lipid fraction (Taylor and Emmambux 2008). Kodo millet contains 64.3 g/100 g carbohydrate (Muragod et al. 2019). Thilagavathi et al. (2015b) reported the starch content of Kodo millet as 58.45 g/ 100 g. Annor et al. (2013) in their study revealed a significant increase in the in vitro starch digestibility and expected glycemic index of kodo millet flour samples after removal of protein, lipid, or both. The effect of lipid removal on in vitro starch digestibility of kodo millet has been found to be significantly more compared to when proteins are removed. The expected glycemic index of cooked kodo millet flour (49.4) increased to 62.5 for millet flour from which lipid and proteins were removed. Decortication processes when applied to kodo millet resulted in removal of

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Nutritional Profile of Small Millets

29

lipid, protein, or both leading to an increase in vitro starch digestibility and expected glycemic index. Therefore, to maintain hypoglycemic property, development of products from whole millets is advocated. Kodo millet contains high amount of fiber. The therapeutic properties of kodo millet can be attributed to its high dietary fiber content. Whole grain millet flour is a richer source of dietary fiber in comparison to milled millet flour, where in the proportion of nutrients and fiber are reduced considerably. Deshpande et al. (2015) reported a high crude fiber content (9.0 g/100 g) in kodo millet as compared to 0.2% in rice. Similar values for crude fiber (8.5 g/100 g) have been reported by Yadav et al. (2013). Srilekha et al. (2019) found a slightly lower amount of crude fiber in kodo millet (4.06%). Hadimani and Malleshi (1993) in their study reported the soluble dietary fiber, insoluble dietary fiber, and total dietary fiber content of kodo millet as 5.2 g/100 g, 6.4 g/100 g, and 11.6 g/100 g, respectively. Thilagavathi et al. (2015b) reported the soluble dietary fiber content of kodo millet as 4.57%. Kodo millet contains water-soluble fiber, and this property may be utilized for maintaining blood glucose response among patients with diabetes and CVD (Yadav et al. 2013) (Table 2.1). Kodo millet is a rich source of minerals such as calcium, phosphorus, and magnesium. The total mineral matter as ash content is high in kodo millet. Thilagavathi et al. (2015a) noted 3.85 mg/100 g iron in kodo millet flour. Gopalan et al. (2016) found that kodo millet contained 147 mg/100 g magnesium which is higher than the values obtained for milled rice (64 mg/100 g), foxtail millet (81 mg/ 100 g), and barnyard millet (82 mg/100 g). The potassium content of kodo millet (144 mg/100 g) is higher than that of proso (131 mg/100 g) and little millet (129 mg/ 100 g) (Table 2.3). Kodo millet is a good source of B vitamins which mainly include nicotinic acid, pyridoxine, and folic acid. Few studies have focused on the vitamin profile of different kodo millet varieties and this area of research needs further investigation. Germination of kodo millet resulted in significant increase in protein content (from 6.7 to 7.9%), dietary fiber (from 35.30 to 38.34 g/100 g), and minerals (from 232.82 to 251.73 mg/100 g) and a decrease in phytates and tannins content (Sharma et al. 2017b). Studies have also shown that kodo millet contains high polyphenol and antioxidant content. The millet shows ample potential to be utilized as a nutraceutical. Kodo millet contains abundant polyphenols, tannins, and phytates. All these compounds can function as antioxidants. The beneficial role of millet-based diet in protecting against oxidative stress and maintaining glucose level in vivo in type II diabetic rats has been investigated by Hegde et al. (2005). The rats fed kodo millet diet showed greater reduction in blood glucose (42%) and cholesterol (27%) than the rats fed finger millet diet. Food products incorporated with kodo millet were acceptable, and they markedly reduce glycemic index. A high fiber content of kodo millet could be a possible reason for a lower glycemic index (Yadav et al. 2013) Thilagavathi et al. (2015b) reported the total polyphenol content of native kodo millet flour as 368 mg/ 100 g which is higher than the values obtained for pearl millet (333 mg/100 g) and proso millet (361 mg/100 g). The antioxidant activity of kodo millet was high

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(70.82 mg AAEAA/100 g) in comparison to little and proso millet. Methanolic extracts of kodo millet showed higher phenolic content and antioxidant activity. The main polyphenols in kodo millet have been identified as ferulic acid and cinnamic acid. Kodo millet polyphenols have been found to be active against foodborne pathogens. The nutritional profile of kodo millet shows that it can be utilized in the formulation of nutraceuticals and functional foods (Sharma et al. 2017a). The total polyphenol content, total flavonoid content, and antioxidant activity of kodo millet increased due to germination. Free and bound phenolic and flavonoid compounds of kodo millet increased after germination, and six new polyphenolic compounds were synthesized during germination in the millet (Sharma et al. 2017b) (Table 2.5).

2.2.4

Nutritive Value of Barnyard Millet

Barnyard millet (Echinochloa frumentacea) is an important small millet in the sub-Himalayan state of Uttarakhand, India. It is also known by several other names such as Japanese barnyard millet, jhangora, madira, sawan, ooda, etc. It is a fast-growing dual purpose crop used both for food and fodder. Its grains are used as cooked rice commonly known in India asbhat, and the straw is good quality fodder (Kumar et al. 2008). It is underutilized small millet. Barnyard millet is a good source of dietary fiber, minerals, and phytochemicals and a fair source of easily digestible protein. Barnyard millet is a nutritionally superior grain containing fair amount of highly digestible protein (10.5%) (Ugare et al. 2014). The protein content of barnyard millet is higher than many commonly consumed cereals. Himanshu et al. (2018) reported the protein content of barnyard millet to range from 6.0 to 13.0 g/100 g. Chandel et al. (2014) in their study observed wide variability in the protein content of barnyard millet which varied from 6.73% to 13.09%. The essential amino acids lysine present in four barnyard millet genotypes ranged from 2.30 to 2.98 (g/16gN) and tryptophan varied from 0.14 to 0.32 (g/16gN). Among small millets, barnyard millet contains higher amount of lysine than little and finger millet; however, it is comparable to that of foxtail millet. Kim et al. (2011) in their study revealed that one of the Korean barnyard millet variety IT153600 exhibited highest total protein (14.75%), lipid (6.92%), and amino acid content (137.10 mg/g). Essential amino acid profile of barnyard millet has been presented in Table 2.2. Shanmugapriya and Nazni (2020) in their study found 2.97% crude fat in raw barnyard millet (Table 2.1). A decrease was observed in the crude fat content (2.77% to 2.39%) with the increase in roasting temperatures. Chouhan et al. (2016) revealed that unprocessed barnyard millet flour contained 2.9% fat which decreased on soaking (2.4%) and germinating (2.4%) of the millet; however, it increased upon roasting (3.4%). Sharma et al. (2016) reported that unprocessed barnyard millet flour contained 5.31% lipid which decreased to 3.4% on germination. The highest linoleic content among Korean barnyard millet varieties (K141286) was 67.6% (Kim et al. 2011). Sridhar and Lakshminarayana (1992) found the total lipids (comprising free,

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bound, and structural lipids) in barnyard millet as 8.0% (71.3, 21.2 and 7.5%). The major fatty acid present in barnyard millet is linoleic acid followed by palmitic acid and oleic acid. Aburai et al. (2007) isolated linoleic acid from methanol extract of proso and barnyard millet as histone deacetylase inhibitor. They stated that millet containing linoleic acid might have antitumor activity. Barnyard millet contains slowly digestible starch and this makes it a useful ingredient for people leading sedentary lifestyle (Malathi et al. 2012; Ugare 2008). Barnyard millet has about 65% carbohydrate, which is mainly present in the form of non-starchy polysaccharides and dietary fiber (Sood et al. 2015). Shanmugapriya and Nazni (2020) found 64.27 g/100 g carbohydrate in raw barnyard millet. A decrease in carbohydrate content was observed with increase in roasting temperature and soaking time. Hymavathi et al. (2020) in their study found that among dehulled small millets (barnyard, little, kodo, and proso millet), barnyard millet had the highest carbohydrate content (74.99 g/100 g). Scanning electron microscope picture of small millet starch granules showed that barnyard millet starch granules were larger in size in comparison to other small millet starch granules (Kumari and Thayumanavan 1997). Barnyard millet starch demonstrates greater degree of retrogradation of amylose. This property promotes the formation of more resistant starches (Malathi et al. 2012). Barnyard millet is a valuable source of dietary fiber. Verma et al. (2015) found that the crude fiber content in barnyard millet was 2.89%. Germination of barnyard millet resulted in significant increase in dietary fiber and minerals; however, phytates decreased (Sharma et al. 2015). Ugare et al. (2014) reported a higher value for total dietary fiber (12.6%) which included (4.2%) soluble and (8.4%) insoluble dietary fiber fraction. Both dehulled (50.0) and dehulled and heat treated (41.7) grains of barnyard millet demonstrated low glycemic index. The study further suggested that feeding intervention was beneficial for type II diabetics and brought about a marginal decrease in triglycerides and increase in HDL cholesterol in diabetic group. Joshi and Srivastava (2016) found that barnyard millet khichdi contains much more crude fiber (6.44 g/100 g) than rice khichdi (0.61 g/100 g) and barnyard millet khichdi also exhibited significantly lower glycemic index (34.96). Studies by Veena et al. (2005) on several varieties of barnyard millet revealed that total mineral content ranged between 1.5 and 4.0%. Barnyard millet is a rich source of calcium and iron (Table 2.3). Verma et al. (2015) found the total ash content in barnyard millet as 4.27%. They reported the calcium and iron of barnyard millet as 26.16 mg/100 g and 6.91 mg/100 g, respectively, which is much higher than rice. It also contains good amount of phosphorus (267 mg/100 g). Salunke et al. (2019) in their study found that calcium, phosphorus, and iron content of barnyard millet were 20.0, 280, and 5.0 mg/100 g, respectively. Shanmugapriya and Nazni (2020) in their study found the potassium, magnesium, iron, zinc, copper, phosphorus, and manganese content of raw barnyard millet flour to be 120.16, 79.43, 4.07, 3.06, 0.17, 254.23, and 0.85 mg/100 g, respectively. Raw barnyard millet flour contained 1.46 mg/100 g tannin and 4.26 mg/100 g total phenolic compounds. The antinutrients phytic acid and tannin decreased upon germination, soaking, and roasting (Chouhan et al. 2016).

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Among small millets, barnyard millet is a good source of niacin (4.2 mg/100 g) and a fair source of thiamine (Table 2.4). Barnyard millet is a good source of antioxidants. Three antioxidative phenolic compounds, one serotonin derivative and two flavonoids, were segregated from an ethanol extract of Japanese barnyard millet (Watanabe 1999). The total phenolic content, total flavonoid content, and total condensed tannin content of barnyard millet was found to be 129.5 (mg ferulic acid equivalent/100 g,DW) 101.3 (mg catechin equivalent/100 g,DW), and 59.54 (mg catechin equivalent/100 g,DW). Barnyard millet also exhibited high 2,20 diphenyl-1-picrylhydrazyl (DPPH) and 2,20 -azino-bis (3-ethylbenzothiazoline-6sulphonic acid) diammonium salt (ABTS) radical scavenging activity (Ofosu et al. 2020). The total phenolics and total flavonoids present in unprocessed barnyard millet were 29.01 mg gallic acid equivalent (GAE/100 g, dw) and 29.02 (mg/g plant extract in rutin equivalent) which increased on germination to 77.68 mg gallic acid equivalent (GAE/100 g, dw) and 71.92 (mg/g plant extract in rutin equivalent), respectively. The free, bound, and total phenolics and flavonoids increased significantly as a result of cell wall degrading enzymes which became active and possibly liberated the bound phenolics (Sharma et al. 2016). Korean barnyard millet variety K141285 showed significantly high total phenolic and flavonoid content (Kim et al. 2011). Germinated barnyard millet flour had higher nutraceutical content than raw barnyard millet flour (Sharma et al. 2015) (Table 2.5).

2.2.5

Nutritive Value of Proso Millet

Proso millet (Panicum miliaceum) is important ancient small millet grown in the United States, China, Russia, Germany, Afghanistan, Africa, Romania, Turkey, and India. Proso millet is also known as common millet, broomcorn millet, hog millet, and white millet. In India, it is known as Chena in Hindi, Pani-varagu in Tamil, and Baragu in Kannada. Proso millet is used in feeding birds and as human food. Compared to other small millets, the nutritional properties of proso millet have been well studied. The protein quality of proso millet is higher than other small millets. The protein content of proso millet is often compared to that of wheat. Kalinova and Moudry (2006) analyzed the crude protein content of proso millet varieties and found that protein content of proso millet (11.6%) was comparable to that of wheat (Table 2.1). Nevertheless, proso millet contained significantly higher amounts of essential amino acids (leucine, isoleucine, and methionine) in comparison to wheat. On the basis of essential amino acid index, protein quality of proso millet was higher (51%) than wheat. They also reported that protein content was significantly influenced by weather during the year, and dry conditions caused an increase in protein content. Gulati et al. (2017) revealed that proso millet protein bears structural similarities with sorghum. Dehulled proso millet flour was subjected to dry and wet heating processing techniques. A significant decline in digestibility of proso millet protein was observed when compared with unprocessed flour (from 79.7% to 42.0%). It was concluded that proso millet protein, termed panicin, forms hydrophobic aggregates

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that are resistant to digestion when subjected to heat. Cooking resulted in a drastic decline in digestibility of proso millet proteins. Prolamin was found to be the major protein fraction in proso millet and with least solubility (Akharume et al. 2020). Lysine is a limiting amino acid in proso millet (Shen et al. 2018). Proso millet is a gluten-free millet. Bagdi et al. (2011) observed that decortications of millet did not affect its protein and fat content. Nishizawa et al. (1996) examined the effect of dietary proso millet protein on plasma levels of high-density-lipoprotein cholesterol in rats. Results showed that ingestion of millet protein elevates plasma level of HDL cholesterol. Park et al. (2008) concluded that proso millet protein could be potential therapeutic intervention in type II diabetes. Lipid content of dehulled proso millet grains ranged from 3.5% to 6.7% (Kalinova 2002). Bagdi et al. (2011) analyzed the free and bound lipid composition of proso millet flours and bran. In the study, it was found that hydrocarbons, sterol ester, triacylglycerol, diacylglycerol, and free fatty acid were present in the free lipids. Proso millet lipids contain 86%–89% unsaturated fatty acids, and polyunsaturated fatty acids constitute about 42% of the unsaturated fatty acids (Kalinova 2007). Puffed grains of proso millet contained 8.43% fat (Pilat et al. 2016). Linolenic acid (61.74%) and oleic acid (22.61%) were major fatty acids present in Chinese proso millet varieties (Shen et al. 2018). Products made from refined proso millet had 1.2% to 6.1% lipid (McSweeney et al. 2017). Kumar et al. (2018) reported the 67.09 g/100 g carbohydrate in proso millet. Native starch of proso millet shows the maximum digestibility (50.0%) in comparison to other millet such as foxtail, kodo, and barnyard (Kumari and Thayumanavan 1997). Proso millet is reported to have glutinous and non-glutinous endosperm types and the glutinous starches have been found to be more digestible than non-glutinous types (FAO 1995). Non-waxy proso millet had more amylose than waxy proso millet. Amylose content of proso millet is positively correlated with pasting properties. Cooked non-waxy proso millet was hard and waxy proso millet was sticky. Non-waxy proso millet contained more resistant starch and lower rapidly digestible starch than waxy proso millet (Yang et al. 2018). Waxy proso millet varieties had lower amylose content (0.21%), higher transparency (29.84%), and lower percentage of retrogradation (5.01%) (Chao et al. 2014). Proso millet varieties differed in amylose content and prolamin profile. Pasta with more amylose content had several properties such as lower cooking loss, lower stickiness, and higher firmness and chewiness, and therefore proso millet may be suitable for fresh pasta. Proso millet pasta contained less rapidly digestible starch than commercial gluten free pasta (Cordelino et al. 2019). Acid modification leads to a reduction in amylose content of proso millet starch (Singh and Adedeji 2017). Proso millet starch granules were found to be polygonal and spherical with smooth surface, and proso millet starches may have potential application in production of puffed starch products (Wen et al. 2014). Proso millet varieties differed considerably in amylose content of starch which was found to range from 7.8% to 34.8%. Lower amylose content in proso millet showed lower peak temperature, final viscosity, and setback. The slowly digestible starch depicts the primary starch fraction of cooked proso millet flour (Tyl et al. 2018).

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According to Ferriola and Stone (1998), the content of dietary fiber in proso millet ranges between 8.9% and 12.5%. Proso millet contains 0.4% hemicelluloses and 2.7% cellulose. The hemicelluloses is mainly composed of glucose, arabinose, uronic acid, and xylose units (Serna-Saldivar and Rooney 1995). Whole grain millet seems to be nutritionally valuable due to its high dietary fiber content (Table 2.1). Decortications of millet significantly reduce several nutritional components such as dietary fiber, minerals, and total phenols present in proso millet (Bagdi et al. 2011). In proso millet with amylose content of 17.2% (dry matter), the resistant starch level was 0.4% w/w on a dry weight basis. This is relatively high value when compared to rice (0.2% w/w dry basis) (Kumari and Thayumanavan 1997). An increase was observed in the dietary fiber content of proso millet upon germination (Ko et al. 2011). Whole grain flour of proso millet contained significantly higher total dietary fiber than the brown or polished millet grain flour, whereas brown grain flour contained significantly higher-soluble dietary fiber than the polished grain flour. Brown grain flour also showed high water and oil absorption capacity (Devisetti et al. 2014). Proso millet is rich in vitamins (niacin, B complex vitamins, folic acid) and minerals (phosphorus, zinc, iron) (Das et al. 2019). Several past studies show that proso millet is a good source of the minerals such as phosphorus, potassium, and magnesium; however, it is a poor source of calcium. Kalinova (2007) reported the phosphorus, magnesium, calcium, iron, and zinc contents of proso millet to range from 156 to 230, 78 to 140, 8 to 20, 0.8 to 5.2, and 1.4 to 2.6 mg/100 g, respectively. The bond of phosphorus with phytate decreases the availability of phosphorus from proso millet. Proso millet is rich in B vitamins especially thiamine, riboflavin, vitamin B6, and folic acid (Mc Donough et al. 2000; Santra and Rose 2013). Native flour of proso millet is rich in polyphenols (361.87 mg/100 g) and has high antioxidant activity (65.74 mg AAEAA/100 g). The phytate content of proso millet is 27.17 mg/100 g and the tannin content is 22.67 mg/100 g. The tannin content of proso millet is higher than that of little and pearl millet (Thilagavathi et al. 2015a) (Table 2.5). The major phenolic compounds in proso millet were found to be pyrogallol, rutin, gallic acid, kaempferol, and salicylic acid (Seo et al. 2011). The free phenolics of proso millet ranged from 27.48 to 151.14 mg gallic acid equiv./ 100 g DW, and bound phenolic ranged from 55.95 to 305.81 proso millet (Zhang et al. 2014). The highest total polyphenol content in proso millet samples was 23.48 mg of (GAE)/ g of sample, and the highest total flavonoid content was 4.49 mg of catechin equivalent/g of sample. The highest total tannin in proso millet samples was 15.59 mg of TAE/g of sample, and the highest DPPH radical scavenging activity in proso millet samples was 12.66 mg of TE/g of sample (Woo et al. 2012). Carotene content in small millet ranges from 7 to 366 μg/100 g and is highest in proso millet and lowest in little millet (Asharani et al. 2010) (Table 2.5).

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2.2.6

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Nutritive Value of Little Millet

Little millet is an ancient small millet grown in India. Other common regional names of little millet (Panicum sumatrense) in India are kutki (Hindi), samai (Tamil), sama (Telugu) and same/savi (Kannada). Little millet is grown to a limited extent in India, up to an altitude of 2100 m. In India, little millet is grown in the states of Tamil Nadu, Karnataka, Andhra Pradesh, Maharashtra, Orissa, Bihar, and Madhya Pradesh. It is described as a quick-growing, short-duration cereal which withstands both drought and water logging. In comparison to other small millets, little millet has received lesser attention and its consumption is limited to the poor and the tribals. Little millet is nutritionally superior to rice and wheat and provides low-cost proteins (Table 2.1), minerals, and vitamins to the poor, where the need of such nutrients is maximum (Dangeti et al. 2013). Barnyard millet is comparable to little millet in its protein and fat content. Chandel et al. (2014) reported the protein content of little millet to range from 7.96% to 10.66%. Kamatar et al. (2013) reported the protein content of little millet landraces to range from 6.87 to 7.26 g/100 g. The protein quality of little millet is considered to be poor (FAO 1995) Pampangouda et al. (2015) reported that fermentation of little millet by combined inoculation of probiotic yeast (S. boulardii) and LAB (L. acidophilus) has been found to be more effective in enhancement of protein. Essential amino acid profile of little millet has been presented in Table 2.2 Himanshu et al. (2018) found that fat content in little millet ranged from 5.0 to 6.0 g/100 g, whereas Kamatar et al. (2013) reported fat content of little millet in the range of 4.64 to 4.70 g/100 g. Kalal et al. (2019) reported lower fat content (2.10%) in little millet with an energy content of 351.65 Kcal. The total lipids in little millet comprising of free bound and structural lipids amounted to 8.3% (Sridhar and Lakshminaryana 1992). The carbohydrate content of little millet is 65.55 g/100 g (NIN 2017). It is a good source of slow-digesting carbohydrate and dietary fiber. Little millet contains 78% carbohydrate and provides 370 Kcal (Kamatar et al. 2013). Kalal et al. (2019) found the carbohydrate content in little millet to be 74.75% with an energy content of 351.65 Kcal. The crude and dietary fiber content of little millet was 3.20% and 12.51%, respectively (Kalal et al. 2019). Nazni and Bhuvaneswari (2015) reported the crude fiber content of little millet as 5.0 g/100 g. Patil et al. (2015) in their study observed that one serving (30 g) of ready to cook flakes of little millet provided 2.25 g of protein, 0.13 g of fat, 0.13 g of total minerals, 9.67 mg of iron, and zero trans fats. These flakes had higher total dietary fiber content (22.40%) and exhibited a medium glycemic index of 52.11. Itagi et al. (2013) developed a little millet composite mix and tested its glycol-lipidemic response among six non-diabetics and nine type 2 diabetics with 4 weeks of feeding. They reported a reduction in plasma glucose and plasma triglyceride and an increase in HDL cholesterol in the experimental group. Little millet is a good source of the minerals phosphorus, magnesium, and iron (Table 2.3). Himanshu et al. (2018) reported the phosphorus, magnesium, iron, and

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zinc contents of little millet as 251–260 mg/100 g, 1.0–20.0 mg/100 g, 13–20 mg/ 100 g, and 3.5–11.0 mg/100 g, respectively. Little millet has a significant role in providing nutraceutical components such as phenols, tannins, and phytates along with macro- and micronutrients (Itagi 2003). The total carotene of little millet flour has been reported to be 78 μg/100 g and total antioxidant capacity is 4.7 mM TE/g (Asharani et al. 2010). Native flour of little millet contains higher proportions of polyphenols (373.67 mg/100 g) with an antioxidant activity of 67.63 mg AAEAA/ 100 g (Thilagavathi et al. 2015b) (Table 2.5). Pradeep and Guha (2011) analyzed the effect of germination, steaming, and roasting on the nutraceutical and antioxidant properties of little millet and noted that maximum increase in total phenolic, flavonoid, and tannin contents was observed during roasting. Roasted millet showed highest radical scavenging activity and iron-reducing power. The major phenolic fractions in little millet are ferulic and gallic acids.

2.3

Comparison of Small Millets with Other Cereals

Extensive past researches have established the fact that small millets are comparative to the widely consumed finer cereals (wheat, rice, and maize) in terms of macronutrients. However, small millets score way ahead popular finer cereals when compared with micronutrients, dietary fiber, antioxidants, and phytochemicals. The calories present in small millets range from 300 Kcal in barnyard millet to 364 Kcal present in proso millet. The calorie contents of wheat, rice, and maize have been found to be 348, 362, and 358 Kcal, respectively. Barnyard, finger, and little millet show a slightly lower calorie content than other cereals and millets (Saleh et al. 2013). Pearl millet, maize, and sorghum also provide similar calories. Among all cereals and millets, raw milled rice contains highest amount of carbohydrate (78.2 g/100 g) which is followed by maize (73.0 g/100 g), sorghum (72.6 g/100 g), and finger millet (72.0 g/100 g). The carbohydrate content of small millets ranged from 63.2 g/100 g (foxtail millet) to 72.6 g/100 g (finger millet). Small millets are equivalent to major cereals in terms of carbohydrate content (Gopalan et al. 2016; Saleh et al. 2013). Milled and polished rice is rich in starch which is easily digested to glucose and metabolized to provide energy. Starch digestion rate affects glycemic index. Starch-loaded milled polished rice is considered a food with high glycemic index, though brown rice fares better in terms of glycemic index (GI) (Jukanti et al. 2020). Wheat grain contains 63%–66% starch. It is a major nutritional component of wheat and is present in the endosperm (Hussain 2009). The protein content of small millets varies from approximately 7.7% in finger millet to 12.5% in proso millet. Among small millets, proso, foxtail, and barnyard millets contain slightly higher protein than kodo and finger millets. Though finger millet contains less protein, it has well-balanced amino acids. It is limited in lysine, but has sulfur-containing amino acids. Studies report protein content of foxtail millet to range from 10% to 15% which is higher than that of rice, wheat, or maize. Barnyard millet too contains higher amount of easily digestible protein than rice

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and maize. Among cereals, different varieties of wheat contain 9.03% to 12.33% protein (Punia et al. 2019). Comparatively rice contains less protein (approximately 7%), and its protein lacks the essential amino acids lysine and threonine (Jiang et al. 2016). Maize contains approximately 10% protein. Nutritionally maize protein has low biological value as it is deficient in lysine and tryptophan amino acids (Nuss and Tanumihardjo 2011). Alamerew (2008) reported the protein content of maize to range from 6.87% to 12.02%. According to Kulamarva et al. (2009), sorghum contains 12.3% protein which is deficient in the amino acids lysine and threonine and has low digestibility. Among small millets and cereals, pearl millet (4.8%) and little millet (5.2%) are richer in fat, followed by maize (4.6%). The lowest fat content is present in finger millet (1.5%). Except finger millet all other small millets contain more crude fat than rice, wheat, or sorghum. The presence of good amount of dietary fiber in small millets is their nutritional strength. Fiber provides and enhances the health benefiting properties of small millets. The crude fiber content of small millets ranges from 3.6% in finger millet to 13.6% in barnyard millet. The crude fiber content of wheat rice and maize is 2.0%, 1.0%, and 2.8%, respectively, which is lower in comparison to small millets (Saleh et al. 2013). Milling, polishing, and refining of cereals lead to drastic reduction in fiber content. Refined wheat flour (0.3%) and milled rice (0.2%) contain very little fiber due to the removal of the fibrous bran layers (Gopalan et al. 2016). Though whole wheat grain contains 11.6%–12.7% fiber (Carson and Edward 2009), which is comparable to fiber present in small millets, most of the wheat is consumed after milling and sieving which results in loss of fiber. Barnyard, little, and foxtail millets score much higher than the finer cereals for crude fiber. Most small millets are rich source of dietary fiber. Finger millet (15–20%), foxtail millet (26.92%), and barnyard millet (12.6%) provide higher amount of dietary fiber per serving (Chethan and Malleshi 2007; Anju and Sarita 2010; Ugare et al. 2014). The crude fiber contents of maize (2.8%), sorghum (2.0%), and pearl millet (2.3%) are lower than small millets (Saleh et al. 2013). Small millets are rich in minerals and vitamins. Finger millet is an exceptionally rich source of calcium (350 mg/100 g) and also contains good amount of iron (3.9 mg/100 g) and phosphorus (283 mg/100 g). The calcium content of finger millet is unmatched by any other cereal or millet. Foxtail and barnyard millets are rich sources of minerals such as iron, phosphorus, and zinc. Little millet contains high amount of iron (9.3 mg/100 g). Neither whole wheat flour nor milled rice contains these vital minerals in such good quantities as drastic losses of their minerals occur during their processing to make them more acceptable. However, pearl millet and sorghum are comparable to small millets with respect to mineral content. Small millets are also rich source of B vitamins, namely, thiamine, riboflavin, and niacin. Whole wheat flour contains comparable amount of B vitamins. These vitamins are present in very small quantities in refined wheat flour and milled rice. Pearl millet and sorghum can provide almost similar quantities of B vitamins. Additionally, pearl millet also contains carotene and folic acid (Saleh et al. 2013; Gopalan et al. 2016).

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Small millets are exceptional source of polyphenols and antioxidants which provide protection against oxidative stress and degenerative diseases. They contain phenolic acids, tannins, and flavonoids. The antioxidants such as vitamin E and carotene are also present in small millets. Highest phenolic content and antioxidant activities in millets have been observed. Dark-colored millets show high phenolic content. Finger millet has higher total phenolic content and total flavonoid content than foxtail or proso millet (Kumari et al. 2017). Mostly small millets are not subjected to much processing, and their whole grain flours are consumed so phytochemicals remain available upon consumption. Rice is not considered a good source of phenolic compounds. Some antioxidant activity providing compounds have been identified in rice such as phenolics, tocopherols, tocotrienols, and γ-oryzanol (Iqbal et al. 2005), but these compounds are reduced in the grain during milling (Walter and Marchesan 2011). Phenolic acids and flavonoids are present in wheat, but their nutritional benefits can only be harnessed from whole wheat products (Zilic 2016). Though whole wheat and indigenous rice varieties which are minimally processed contain polyphenols and antioxidants, these nutritionally valuable compounds are lost during milling, polishing, and sieving.

2.4

Conclusion

Small millets are versatile crops which sustain in adverse agroclimatic conditions, provide food security, and are highly nutritious. In general, small millets are important source of energy, protein, B vitamins, minerals, dietary fiber, and phytochemicals. Each small millet individually has some unique nutritional properties. Finger millet is an exceptionally rich source of the mineral calcium and has a well-balanced amino acid profile. It is rich in dietary fiber and contains a variety of phytochemicals. Among small millets, foxtail millet contains good amount of protein, dietary fiber, and antioxidants. Its barn is rich in unsaturated fatty acids. Kodo millet has low fat and high dietary fiber content. It is a rich source of polyphenols and antioxidants. Barnyard millet contains highly digestible protein. It is also a good source of dietary fiber, iron, niacin, and thiamine. Proso and little millets are rich sources of mineral, B vitamins, phytochemicals, and antioxidants. Small millets on some nutritional parameters compare well with the major cereals, while they seem to be superior to the major cereals in terms of dietary fiber, micronutrients, phytochemicals, and antioxidants. The excellent nutrient profile and associated health benefits have rekindled the interest of scientists and nutritionists in small millets. Owing to their nutritional profile, small millets can be judiciously utilized in formulating therapeutic foods and dietary supplements.

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Xiang J, Apea-Bah FB, Ndolo VU, Katundu MC, Beta T (2018) Profile of phenolic compounds and antioxidant activity of finger millet varieties. Food Chem. https://doi.org/10.1016/jFoodChem. 2018.09.120 Yadav N, Chaudhary K, Singh A, Gupta A (2013) Evaluation of hypoglycemic properties of kodo millet based food products in healthy subjects. IOSR J Pharm 3(2):2250–3013 Yang Q, Zhang P, Qu Y, Gao X, Liang J et al (2018) Comparison of physicochemical properties and cooking ability of waxy and non -waxy proso millet (Panicum miliaceum L). Food Chem 257:271–278 Yin YS, Kao SH, Chen YR, Trai YC, Lin YR (2019) Genetic variation of physicochemical properties and digestibility of foxtail millet (Setaria italica) landraces of Taiwan. Molecules 24(23):4323 Zhang B, Jing L, Cheng L, Zhang Y, Hou S, Sun ZX, Li HY, Han YH (2019) Carotenoid composition and expression of biosynthetic genes in yellow and white [Setaria italica (L.) Beauv]. J Cereal Sci 85(33):84–90 Zhang L, Liu R, Niu W (2014) Phytochemical and anti-proliferative activity of proso millet. PLoS One 9(8):e104058. https://doi.org/10.1371/journal.pone.0104058 Zhang ZL, Liu RU (2015) Phenolic and carotenoid profile and anti-proliferative activity of foxtail millet. Food Chem 174:495–501 Zhu Y, Chu J, Zhaoxin L, Lu F, Bie X, Zhang C, Zhao H (2018) Physicochemical and functional properties of dietary fiber from foxtail millet (Setaria italica) bran. J Cereal Sci 79:456–461 Zilic S (2016) Phenolic compounds of wheat their content antioxidant capacity and bioaccessibility. MOJ Food Process Technol 2(3):85–89

3

Processing of Small Millets Anju Bisht

Abstract

Processing is the treatment of cereals after harvesting so as to convert them into edible form. Processing aids in removal of unwanted part and concentrates the desirable part for consumption. Small millets, which are storehouse of nutrients, need to be processed so as to increase the availability of nutrients, remove antinutrient factors, and thus transform them into edible form. But owing to their structure and size, processing of small millets becomes quite difficult, which unfavorably affects their production and consumption to a large extent. This chapter discusses the various primary and secondary techniques of processing small millets. These processing techniques can be adopted to ease the processing of small millets and utilize them for preparing nutritious traditional and unconventional food products. Keywords

Small millets · Processing techniques · Decortication · Milling · Parboiling · Popping · Malting · Flaking · Extrusion · Fermentation

3.1

Introduction

Unlike the multi-chambered stomach of herbivores, the human beings cannot eat the grains as such. The grains need to be processed before consumption so as to make them easily digestible. Generally the grain processing is a physical process that separates bran and germ, removes the unwanted part, and concentrates the desirable part, thereby increasing the bioavailability of nutrients. The procedure of processing A. Bisht (*) Department of Home Science, MB Government PG College, Nainital, Uttarakhand, India # The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Srivastava (ed.), Small Millet Grains, Cereals, Pulses and Oilseeds, https://doi.org/10.1007/978-981-16-9306-9_3

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starting from harvesting till consumption is collectively referred as postharvest treatment. The postharvest treatment undergoes three steps. First stage starts with harvesting till grain storage. In the second stage, stored grains are cleaned, husk is removed, and grain is reduced to a smaller size. Various treatments like grading, sieving, sorting, hulling, milling, pounding, tempering, parboiling, soaking, and drying are performed. These treatments are known as primary processing of cereals. The third stage is secondary processing of cereals where primary processed grains are converted into edible products. Secondary processing of cereals involves processes like baking, puffing, popping, extrusion, flaking, fermentation, and frying (www.fao. org). Post harvest Processing

1st stage

2nd stage

Harvesting

Primary Processing

3rd stage Secondary processing

(grading, sieving, sorting, hulling, (baking, puffing, popping, Storage

milling, pounding, tempering, parboiling, soaking, drying)

3.2

flaking, fermentation, frying extrusion)

Structure of Small Millets

Before understanding the processing techniques suitable for small millets, there is a need to understand the structure of millet grain, which influences the processing techniques. Like any other cereal grain, small millet also has three components: pericarp (outer layer), germ or embryo, and endosperm. The outermost layer of millet grain is pericarp, which consists of three layers, epicarp, mesocarp, and endocarp, followed by testa or seed coat and then aleurone layer. Beneath is endosperm, which contains peripheral, corneous, or floury zone in different proportion in different millets. Some small millets having soft texture kernel have more of floury and less of corneous endosperm, whereas in hard texture kernel, more of corneous endosperm and less of floury endosperm are present. For instance, foxtail millet has little floury endosperm and more of corneous endosperm and therefore has a hard texture. Finger millet and proso millet have equal amount of both. The composition of these anatomical parts, their layers, and the way they are attached

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affect the processing process. Millets can be classified into two seed types, utricle type and caryopsis. Among the small millets, finger millet, proso millet, and foxtail millet are utricle type, which implies that their pericarp is like a sac loosely attached to endosperm at one point, and therefore, the pericarp can be easily removed. On the other hand, kernels of pearl millet are caryopsis type where the pericarp is completely fused to endosperm (FAO 1995).

3.3

Techniques of Processing Small Millets

Small millets are being consumed by human for centuries. They formed the staple diet of Asian and African countries. Though they are highly nutritious and have therapeutic properties, still owing to drudgery involved in processing, small millets have not gained the popularity as expected. Small millets are being processed traditionally in areas where they are consumed on a regular basis. The traditional processing techniques are laborious and time consuming. The common traditional technique used is hand pounding followed by winnowing and milling done by stone chakki and grinding into flour. Besides, certain other processes like fermentation, malting, and roasting are also done traditionally. In Uttarakhand, state of India, still traditional methods are practiced for processing of small millet grains in villages. Small millet grains like finger millet, foxtail millet, barnyard millet, and proso millet are harvested and sun dried. After sun drying, the stalks are either thrashed manually or trodden by bullocks (especially in the case of barnyard millet), and the grains are freed from the stalk. Then, the grains are pounded manually by a wooden pestle in a hole made on the ground, which serves as mortar, followed by winnowing to remove the husk, and then finally, the grains are ground in stone chakki in which the flat, lower stone plate is fixed and the upper plate is rotated manually with the help of a wooden handle. Pradhan et al. (2010) have also reported the traditional method of processing kodo millet, which is completely manual. The method is similar as mentioned above. The only difference is that the plates of chakki are made up of mixture of soil and straw in a particular proportion that check deflocculating. Mill is repaired at a regular interval with muddy paste made of soil and cow dung, which is finally sun dried. The grain recovery in this type of mill is better than stone grinding mill. Leg pounding is done for separation of glumes, lemma, and plea.

3.3.1

Decortication

Decortication is the process of removal of hull in order to improve the sensory and edible properties of grains. It is also known as dehulling or depearling. It is quite difficult in the case of small millets as compared to other cereals because small millets are smaller in size and some small millets have irregular indentation in pericarp. Traditionally, small millet grains are decorticated by hand pounding

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followed by winnowing or sieving. Modern method of decortication involves use of abrasive discs or attrition-type dehuller. To quicken and ease the process of decortication, hydrothermal treatment of millet has been developed. Hydrothermal processing involves steeping the millet to its equilibrium moisture content, followed by steaming and finally low-temperature drying. This process imparts hardness to the kernels enabling easier and faster decortication. Different methods have been developed for decortication of various small millets. In a study, two hydrothermal treatments for kodo millet were found to be most suitable. In first method, kodo millet was soaked in water at room temperature for 24 h, and then, steam pressure of 1 kg/cm2 for 15 min was applied. In second method, kodo millet was soaked in hot water (72  C for 3.5 h) and steamed at a pressure of 1 kg/cm2 for 15 min. These methods resulted in high dehulling efficiency, head rice yield, and milling recovery with the least broken grains (Chandan Kumar 2015). Another method for hydrothermal processing of finger millet standardized by Dharamraj et al. (2013) is shown below.

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Millet cleaning steeping (to equilibrium moisture) draining off water Steaming (atmospheric/ high pressure)

Drying (sun/shade/mechanical)

Hydrothermally processed millet

Tempering (5% additional water, 10-15 min)

Decortication (Carborandum disc mill)

Seed coat

Brokens Head rice Tempering (4% additional water, 10-15 min)

Decorticated millet Source: Dharamraj et al. (2013). Method developed for decortication of finger millet by Malleshi (2003) and Shobana and Malleshi (2007) is shown below with the help of flow diagram:

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Finger millet

Cleaning

Soaking/steeping in water at 20-700C for 2-16 hours

Steaming at atmospheric pressure or upto a pressure of 5kg/cm2 for 2-20 min

Drying to 8-16 % moisture

Decortication in abrasive cereal mill

Aspiration of seed coat and grinding decorticated millet

Decorticated millets

Broken grits

seed coat (husk &bran)

Source: Malleshi (2003). Decorticated finger millet (Eleusine coracana) and a process for preparing decorticated finger millet. Patent Pub. No. US20030185951A1.

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Finger millet Equilibrate at 33±2 % moisture Steaming 20 min at atmospheric pressure Drying to 12±2% moisture Hydrothermally treated millet grading moist conditioning Decortication Aspiration Decorticated millet

Source: Shobana and Malleshi (2007). The above process helps to harden the millet kernel from 1.1 to 7.1 kg/m2 and helps decortication of finger millet with the help of horizontal carborundum disc mill. Poshadri (2015) used rice milling machinery with suitable adaptation for decortication of millets. Centrifugal sheller was used for dehusking. The husked millets were further debranned in a horizontal emery cone. Husk and bran formed about 26% of the millets. Ganesan and Vardharaju (2013) optimized the machine parameter of centrifugal dehuller to remove the outer husk and bran of foxtail and little millet. They found that a moisture content of 12%, peripheral speed of 47.29 m/s, 3-vane impeller, angular casing, and two passes were the most suitable conditions where the broken percentage of grain was less than 5%. Dixit et al. (2011) reported that Vivek Thresher cum Pearler developed by PHET, VPKAS, Almora, was the most suitable for hilly regions. Nayak (2017) has designed and developed kodo millet dehusker (roller concave type), which worked on the principle of abrasion and frictional forces. The dehulling efficiency of dehusker ranged from 72.5 to 75.29% with a minimal processing cost of 6.23 per kg after suitable pretreatments of small millets. Decortication facilitates to cook finger millet similar to rice; otherwise, traditionally finger millet is mostly ground and made into chapattis (unleavened bread). Although decortication process helps in removing the fibrous seed coat, astringent flavor, off-coloration, and anti-nutritional factors, but excess decortication leads to loss of nutrients. Therefore, there is a need to optimize the conditions of

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Fig. 3.1 Decorticated small millet grains

decortication of small millet so that no excess loss of nutrients occurs and only undesirable constituents get eliminated. Figure 3.1 shows decorticated small millet grains.

3.3.2

Milling

Milling includes reduction of endosperm of decorticated small millets. Milling of cereals depends on its morphological structure—shape of grain, its hardness, and adherence of outer layers. As already mentioned earlier, the ease of milling depends on the type of kernel. For instance, in finger millet, the glumes are not fused with seed coat or testa, and therefore, the pericarp can be easily removed. Traditionally, it is done manually by pulverizing the grains in stone chakki. On the other hand, barnyard millet grains are firmly encased in the lemma and palea and therefore need repeated pounding in mortar. Hammer or roller mills are usually used for grain milling, but the flour from hammer mill contains large size of particles and is not uniform. They are not convenient for preparation of thin- and smooth-textured food like porridge and baked and steamed products (Rathore et al. 2016). In the process of wet milling of small millets, the millets are soaked overnight. Soaking softens the endosperm and toughens the pericarp. Soaking is followed by grinding into paste rather than flour as in the case of dry milling. Researchers have developed and documented various traditional and modern milling methods of small millets. Traditional method of milling millets documented by Kajuna (2001) is shown below:

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Clean dry grain tempering Decortication with mortar and pestle Bran

Winnowing

Stone mills

Decorticated grains

sieving

Reduction to flour with mortar and pestle Sieving

grits

Flour

grits (semolina)

Flour

Source: Kajuna (2001) Traditional milling method of millets. Malathi et al. (n.d.) in their report had documented the method of milling barnyard millet, foxtail millet, kodo millet, little millet, and finger millet, in which the grains were sundried for 5–6 h, followed by conditioning (addition of water at the rate of 50 ml per kg) and thorough mixing. The moistened grains were kept in an airtight steel drum for 3 h at room temperature, followed by pearling of grains and sun drying for 6–8 h. Finally, the dried grains were pulverized to obtain millet flour. Double chamber centrifugal dehuller with a capacity of 75 kg/h was used. In modern milling method of small millets, machines make the task easier and faster. Three types of processors are used during milling of millets at a commercial scale. These are abrasive decorticator, metal friction machines, and roller mill. The Central Institute of Agricultural Engineering (CIAE, ICAR) Bhopal has devised a machine for grinding 100 kg in an hour at 10–12% moisture with simultaneous separation of husk with suction and cyclone separator. It is suitable for foxtail millet, barnyard millet, kodo millet, proso millet, and little millet (Balasubramanium 2013). The postharvest technology center of Tamil Nadu Agriculture University, Coimbatore, has designed a millet dehuller that works on the principle of centrifugal and impact force. The machine consists of hopper, impeller, casing, aspirator, grain outlet, and husk outlet. During the process, the grains hit the hard casing surface where the husk splits from the grain and the grain and husk are collected separately by the means of aspirator (www.dhan.org/smallmillets). A combination of rubber roller mill and centrifugal mill was found to be suitable for milling kodo millet (Chin et al. 2012). Karthikeyan (2020) has suggested that three types of millet processing machines, viz., aspirator, destoner, and dehusking/dehulling machine, are needed to process small millets at the place of their production. Basically rice and pulses processing machines after some improvisation were used for primary processing of small millets. Now three types of dehuller/dehusker have been developed for primary processing of small millets. These are rubber roller mill based on compression–shearing principle, emery mill based on abrasion principle, and centrifugal type based on impact principle.

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In a popular article, Bala Ravi (n.d.) has advocated that the millets can be processed in wheat or rice processing units. Owing to its utricle-type structure, finger millet can simply be milled in roller wheat flour mill and husk removed by sieving, but the other small millets require dehusking, debranning, and milling. For other small millets, cone polisher, centrifugal rice sheller, and rice polisher can be used and rice can be obtained, and further, the grains can be pulverized in plate or hammer mill to make semolina or flour. However, the recovery rate in the above method is quite low. Modern method of milling millets is shown below: Millet Conditioning Dehusking

Rubber roll sheller

runner disc sheller

Dehusked grain with Polishing

Husk Bran

Grinding Refined millet flour

Source: Patil (n.d.). Advances in processing of food grains (www.authorstream. com). With an aim to increase the dehulled yield, researches on pretreatment of millet grains have been conducted. Poongodi Vijayakumar et al. (2010) carried pretreatment experiments with barnyard millet. Three treatments were done: first, soaking of millet in cold water for 6, 12, 18, and 24 h followed by steaming for 20 min; second, soaking millet grains in hot water (70  C) for 1, 2, 3, 4, and 5 h, followed by steaming for 20 min; and third, steaming for 10, 20, 30, and 40 min. The millets were dried in sun and shade. The dried millets were milled in rice polisher equipped with emery roller and finally ground in pullizer mill and sieved through 40-mesh sieve. It was seen that barnyard millet that was soaked for 24 h in cold water and steamed for 20 min was best in terms of dehulling yield and also protein content. Similar methods were adapted by Malini et al. (2013) for processing kodo millet and found that steaming method was best compared to cold water and hot water soaking followed by shade drying rather than tray drying.

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Fig. 3.2 Polished barnyard millet grains

Ravindra et al. (2008) studied the primary processing method for little millet using rubber roll sheller cum abrasive grain polisher and provender mill. Out of the various treatments given to little millet, the highest dehusking efficiency was found when little millets were heated with boiling water for 20 min and sun dried. Provender mill had a higher dehusking efficiency compared to rubber roll sheller cum abrasive grain polisher. It was seen that head rice yield ranged from 67 to 73% and 48.7 to 67.9% for various pretreatments for little millets milled with rubber roll sheller cum grain polisher and provender mill, respectively. A double chamber centrifugal dehuller has been developed for processing of small millets (finger millet, little millet, kodo millet, and foxtail millet) by Durairaj et al. (2019). The dehuller consisted of feed hopper, centrifugal chamber, impeller, blower, and collector. The splitting of millet occurred due to impact, which was segregated and collected as husk and kernel. The recovery rate from double chamber centrifugal dehuller was found to be better than abrasive type of dehuller. Development of efficient milling technology will help in increasing utilization of millets and formulation of novel food products from millets with desirable qualities. Figure 3.2 shows polished barnyard millet grains.

3.3.3

Parboiling

Parboiling is a hydrothermal treatment done with an objective of increasing nutritive value and yield of head grain with minimum breakage of grain. The hydrothermal treatment facilitates decortication and increases digestibility, bioavailability of nutrients, and antioxidant content. Parboiling process facilitates dehusking of small millet like kodo millet and eliminates stickiness in cooked finger millet porridge as it gives a lower peak viscosity on cooking (FAO 1995). During parboiling treatment of millets, time and temperature of steeping, steaming, and drying play an important role. The parboiling treatments are grouped into three methods shown below:

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Grains

Conventional parboiling

dry heat parboiling

saturated soaking

Saturated soaking

Steaming

low moisture parboiling

Partial soaking High pressure steaming

High pressure steaming Conduction steaming

Drying

Natural

Artificial

Source: Mir et al. (2015). Different conditions for hydrothermal treatment of small millets have been standardized by the researchers. These have been explained with the help of flowchart shown below: Finger millet

Steeping (10 hours at 30oC)

Draining out of excess water

Steaming (atmospheric pressure for 30 min)

Drying the steamed millet at 39±1oC (14% moisture)

Hydrothermally treated finger millet

Source: Ushakumari (2009).

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Little millet

Steeping (700C for 3 hours)

Steaming (1100C for 20 min.)

Drying in cabinet drier (8-10 hours until 9 % moisture)

Source: Mannuramath and Yenagi (2015). Parboiling conditions were standardized on the basis of milling and cooking quality and consumer acceptability. Parboiling enhances the hulling efficiency and recovery of head rice in foxtail millet and little millet (Varadharaju and Ganesan 2017). Therefore, it can be inferred that parboiling is a cost-effective and efficient technique for processing small millets.

3.3.4

Popping/Puffing

Popping/puffing is a processing technique in which grains are exposed to high temperature for short time. During the process, the kernels get heated, and the vapor cooks the endosperm, expands it, and breaks the outer pericarp to release itself. Millet varieties with hard endosperm and medium-to-thick pericarp are found to be suitable for popping. The basic difference between popping and puffing is that during puffing, native grains are subjected to high-temperature short-time (HTST) treatment, whereas during popping, decorticated and parboiled grains are subjected to HTST treatment. Therefore, in the process of puffing, seed coat acts as a pressure vessel, which results in explosion of the entire endosperm; on the other hand, in the case of popping, the steam is formed in the void of the endosperm causing expansion uniformly in all the directions. Traditional method of popping involves popping in sand or popping with salt. In the sand popping, sand is heated in a metal pan at about 250  C, followed by addition of grains/millets in the heated sand, and is stir continuously. Upon exposure to

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sudden thermal gradient, the moisture inside the grain vaporizes and escapes by breaking the pericarp. During this process, expansion and cooking of endosperm occur simultaneously. Similar process is followed in salt popping, wherein salt is used as popping medium instead of sand. Mishra et al. (2014) in their review article has explained various methods of puffing/popping. Gun puffing is a process in which milled grains are subjected to gun or high-pressure chamber after preheating, followed by introduction of superheated steam in a closed rotating chamber. Optimum steam pressure is critical to obtain the desirable crispiness in grains. Fluidized bed puffing or popping is another modern method of puffing or popping in which fluidized bed popping machine is exposed to high temperature for short time. Fluidization is an effective method compared to traditional method of popping because product surface area is uniformly exposed to heating medium. Microwave popping has also gained popularity in the recent past. During microwave popping, microwave energy heats the product/grains; consequently, moisture is generated, which produces steam, thereby expanding the endosperm. All the above discussed traditional or modern methods of popping/puffing are based on the same principle, except their medium of heat transfer. The method of processing may differ on the type of heat like dry heat, heating in moist condition, and heating with oil as medium. Various small millets like finger millet, barnyard millet, foxtail millet, proso millet, and kodo millet have been processed by means of popping. The processing technique of various small millets is shown below with the help of flow diagram. The method that shows maximum puff yield and expansion volume is presented below with the help of flow diagram and Fig. 3.3 shows popped finger millet grains. Proso millet Tempering at 15 or 18 % moisture Equilibrate for 72 hours at room temperature Gun puffed at 140 0r 160 psi Puffed proso milet

Source: Delost-Lewis et al. (1992).

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Foxtail millet Moistened with 10 % moisture Equilibrate for 4 hour in closed container Conditioned sample added to heated sand (230oC) for 15 s Removed from flame and sieved through 12 mesh sieve

Source: Choudhary et al. (2011). Kodo millet Conditioning at 4% moisture popping

popped kodo millet (60g) Grinding Precooked kodo flour

Source: Prasad (n.d.)

Husk-bran+unpopped grain (32g)

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Decorticated finger millet

Tempering (40% moisture)

Mechanical impact (shape factor 0.52-0.58)

Drying (42±2oC till 9 % moisture) HTST treatment

(salt as medium 225±5oC; Millet: salt::1:4)

Expanded finger millet

Source: UshaKumari (2009). Kodo millet Cleaning and soaking for 24 hours Conditioning for 15-20 min at room temperature (19 % moisture) Puffing in open earthen pot (2300C for 30 min)

Source: Patel et al. (2018). Fig. 3.3 Popped finger millet grains

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Processing of Small Millets

3.3.5

65

Malting

Malting is a biotechnological technique in which controlled germination is done. Malting increases bioavailability of nutrients and improves sensory qualities and digestibility. Malting is being done traditionally in East African countries since long. The traditional method includes steeping of grains for 24 h, followed by germination in a 5–10 cm thick layer under damp burlap bags for 2–3 h. The germinated malt is subjected to sun dehydration for 1–2 days at 25–30  C. Researches have been done in order to standardize the condition of malting of different millets. These have been shown below with the help of flowcharts: Foxtail millet Wash with 0.05% aqueous lime volume of water for 12-48 h till moisture reaches 40% Change water every 6 h Keep grains in muslin cloth for germination for 3-5 h Sprinkle water every 12 h Preliminary drying in air for 1-2 h Final drying under sun till 10% moisture

Grinding of grains to fine particles manually Sieve

Source: Laxmi et al. (2015). Finger millet Steep in excess water for 48 h in aluminum pot Germinate at room temperature for 2 days During germination turn the grains and moisten twice a day Spread the grains and dry in an oven at 400 C for 24 h malt

Source: Shayo et al. (2001).

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Chilkawar et al. (2010) have also conducted studies to standardize the malting conditions for finger millet. The malt yield was found to be highest when the millet grains were steeped for 8 h and sprouted for 24 h. However, the finger millet malt obtained after soaking of grains for 16 h and sprouting for 48 h was considered as standardized procedure as the malt obtained showed the highest in vitro protein digestibility and in vitro starch digestibility and low paste viscosity. The standardized procedure has been shown below in the flowchart:

Finger millet cleaning steeping (16 hours)(grain:water::1:3, SO2 added at 0.2%) changing water every 4 hours draining of water spreading steeped grains on perforated trays lined with muslin cloth germinating in BOD incubator for 48 hours (250C) drying at 650C Removing husk and rootlets Grinding germinated grains Sieving (particle size 80 mesh) Finger millet malt Source: Chilkawar et al. (2010). During malting, with the increase in germination time from 8 to 24 h, increase in protein content was observed from 14 to 17.5% (Swami et al. 2013). Also it was observed that finger millet grains when steeped in water at a ratio of 1:5 w/v for 24 h at room temperature and germinated for 48 h at 30  C led to a decrease in antinutritional factors like phytic acid, tannins, and oxalates and increased in vitro protein digestibility (Hejazi and Orsat 2016). Figure 3.4 shows germinated finger millet and malted finger millet flour. Choudhary et al. (2011) standardized the method of malting foxtail millet, which is shown below:

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Fig. 3.4 (a) Germinated finger millet (b) Malted finger millet flour

Foxtail millet grains Steep in water (4 times) for 20 hours Drain water Germinate at 20-300 C for 72 hours Wash the seeds and spread on a blotting paper to remove excess moisture Sun dry Toast the millets in a skillet at 80-1000C for 15 min Remove the sprouts with hand abrasion Grind millet in a grinder Sieve through 40 mesh sieve Millet malt

3.3.6

Flaking

Flaking is the process of pressing the grains after optimal treatment to prepare flakes. It can be defined as controlled steam gelatinization under pressure followed by rolling technique. According to Poshadri (2015), flaking involves hydration of

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millets to equilibrium moisture content, followed by roasting or steaming to gelatinize the starch. Further, the grains are dried, conditioned, decorticated, and pressed to obtain the flakes. The pressing is done by passing through the edge runner. The general flowchart for preparing flakes is shown below: Small millets Boil in water for 20 min and leave overnight Adjust pH 8-8.5 Wash the grains Steam for 20 min. Dry to 20% moisture Pass through flaking machine Flakes

Various researchers have standardized the methodology of developing small millet flakes. Kotagi (2011) has prepared ready-to-eat little millet flakes with the following procedure: Tempering

Steaming (20lbs/psi, 180oC, 20 min.)

Cooling (30 min.)

Pressing in roller (70 rpm, 0.25mm gap)

Sun drying (4 to 6 hours)

Little millet flakes

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Lenkannavar (2010) prepared ready-to-use flakes from barnyard millet using the following methodology: Tempering

Steaming (18-19lbs/psi, 180oC, 20 min.)

Cooling (30 min.)

Pressing in roller (70 rpm)

Sun drying (4 to 6 hours)

Barnyard millet flakes

The abovementioned method was also adopted for preparing ready-to-cook foxtail millet flakes by Aigal and Chimmad (2017). Takhellambam et al. (2016) standardized the method for preparing flakes from little millet, barnyard millet, proso millet, and finger millet. The ready-to-use/ready-to-cook millet flakes were found to be high in fiber, iron, and zinc and low in fat than their counterparts like native millets, corn flakes, or rice flakes. Little millet flakes showed medium glycemic index, which was relatively lower than rice flakes (Patil et al. 2015). Thus, processing of millets, besides enhancing variety, also makes the product superior in nutritive value and therapeutic value.

3.3.7

Extrusion

Extrusion is a high-temperature short-time method wherein a combination of ingredients are forced through an opening in a perforated plate or die and finally cut to the desired size with the help of knives or cutter. The method is suitable to prepare snacks/ready-to-eat food/convenient food. Extrusion process includes various operations like mixing, cooling, kneading, shearing, shaping, forming, and sizing. The principle of extrusion is based on feeding of raw material into the extruder barrel and conveying the food with screws along it. When the food mix goes through the barrel, smaller flights control the volume and increase the resistance to movement of food, as a result of which frictional force increases the temperature and pressure. Finally, the food is extruded through the dies into the atmosphere (Tiwari and Jha 2017; Bordoloi and Ganguly 2014).

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The extrusion process involves the following equipment: Blender

Variable speed feeder

Extruder

Cooling unit

cutter Dryer

Millets have been explored for the development of extruded products. Poshadri (2015) has given the simple procedure of preparing extruded products based on millets: Millets Blending to prepare composite flour Conditioning to adjust moisture Extrusion cooking Extrudates Drying Cooling Packaging

Source: Poshadri (2015). Amruth Kumar (2013) has standardized the foxtail millet–based extruded product using various combinations. Based on sensory evaluation, four combinations were found to be acceptable. These combinations were: 1. 2. 3. 4.

Foxtail millet grits (80%) + little millet grits (10%) + Bengal gram flour (10%) Foxtail millet grits (80%) + proso millet grits (10%) + Bengal gram flour (10%) Foxtail millet grits (80%) + kodo millet grits (10%) + Bengal gram flour (10%) Foxtail millet grits (60%) + barnyard millet grits (30%) + Bengal gram flour (10%)

The foxtail millet and proso millet combination was selected to be the best. The extruded millet–based product was prepared using twin screw extruder at 110  C, 350 rpm of screw speed. The millet grits’ size was 1201–592 μm and 14–18% of moisture. Similar work was done by Sudha Devi (2012) where all the five small millets, viz., foxtail millet, barnyard millet, little millet, kodo millet, and proso millet, were used to prepare two types of extruded products: cold extruded pasta and hot extruded

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ready-to-eat snack. For preparing pasta, small millet flour was combined with wheat flour, and based on sensory score, the best acceptable combinations were: 1. 2. 3. 4. 5.

Foxtail millet flour (70%) and wheat flour (30%) Little millet flour (50%) and wheat flour (50%) Kodo millet flour (60%) and wheat flour (40%) Proso millet flour (60%) and wheat flour (40%) Barnyard millet flour (50%) and wheat flour (50%)

For preparing ready-to-eat snack, millet grits were combined with corn grits. Twin screw extruder at temperature of 110  C and speed at 350 rpm was optimized. Based on the sensory scores, the acceptable combinations were: 1. 2. 3. 4. 5.

Foxtail millet grits (60%) and corn grits (40%) Little millet grits (50%) and corn grits (50%) Kodo millet grits (60%) and corn grits (40%) Proso millet grits (60%) and corn grits (40%) Barnyard millet grits (50%) and corn grits (50%)

Geetha et al. (2016) also developed foxtail millet–based extruded product. They used the composite flour as a blend of foxtail millet, rice, chickpea, and flax seed in the ratio of 50:15:32:3, respectively. The extruded product was prepared using twin screw extruder at 115  C at a screw speed of 400 rpm. To improve the nutritional quality and digestibility, blend of millet flour in the combination of pearl millet (40%), finger millet (30%), and foxtail millet (30%) was used, and ready-to-eat extruded snack was produced using twin screw extruder with a screw speed of 350 rpm and at 120  C temperature (Wadikar et al. 2014). A combination of millets with other ingredients like kodo millet:chickpea flour (70:30) (Geetha et al. 2014); foxtail millet:amaranth:rice:Bengal gram:cowpea (60: 5:5:20:10) (Deshpande and Poshadri 2011); brown finger millet flour:maize flour: rice flour:full fat soy flour (20:50:20:10) (Sawant et al. 2013); and little millet:rice flour:maize flour (10:45:45) (Saini and Yadav 2018) were standardized to prepare the small millet–based extruded product. The condition of extrusion varied from screw speed ranging from 280 to 400 rpm and temperature from 115 to 140  C. Germinated foxtail millet and precooked/roasted soybean combination was used to develop extruded low-glycemic-index breakfast food (Coulibaly et al. 2012). Millets in combination with mung bean flour and nonfat dry milk were processed in single screw extruder to prepare precooked, ready-to-eat weaning food (Malleshi et al. 1996). Almost all the small millets have been explored for the development of extruded products. The process of extrusion facilitates the availability and digestibility of nutrients and reduces the anti-nutrients. Also, it is an effective processing technique to increase the versatility of small millet–based food products. The process of extrusion can be widely used to develop ready-to-eat and ready-to-cook food like vermicelli, pasta, noodles, etc. A judicious blend of small millets with other ingredients and

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Fig. 3.5 Extruded barnyard millet product

controlled extrusion conditions can not only improve the nutritional value of extruded food products but also products with desired organoleptic properties can be obtained. Figure 3.5 shows extruded barnyard millet product.

3.3.8

Fermentation

Fermentation is an age-old technique to process the grains. It is widely used for increasing the shelf life of food products. Fermentation also reduces the antinutritional components and increases the digestibility and nutrient bioavailability. The application of process of fermentation leads to a variety in food products. Millets have been explored for fermentation. Various food products and beverages, both alcoholic and nonalcoholic, have been developed based on small millets. Finger millet has been extensively explored for preparing fermented food products and beverages. Soor is an alcoholic beverage (5–10%) made from finger millet. A mixture of barley and a local herb known as dhaeli is used to carry out fermentation process. Soor and jann alcoholic beverages made from finger millet and foxtail millet are consumed by Himalayan tribes. Koozh is also a fermented beverage made from either finger millet or pearl millet. Preparation of koozh involves two-step fermentation processes. Madua, bhangchang, mingri, lohpani, and themsing rakshi are the fermented beverage made from finger millet and very popular in Arunachal Pradesh, India (Sekar and Mariappan 2007; Thirumangaimannan and Gurumurthy 2013; Shrivasatava et al. 2012). Besides the abovementioned millet-based fermented products, Amadou et al. (2011) have reported that millets have been utilized to prepare traditional products like porridge locally termed as koko, fura, braza, darassum, uji, ogi, and ben-saalga and alcoholic and nonalcoholic beverages termed as mangisi, jandh, burukuttu, pito, kunu-zaki, bushera, togwa, and jann. Decorticated little millet has also been utilized to prepare fermented product, locally known as paddu. In the process of making paddu, little millet was soaked for 6 h and further ground into a fine batter. Other required ingredients were mixed, and batter was allowed to ferment in an incubator at 30  2  C for 12 h (Madalageri 2012). Finger millet– and barnyard millet–based idlis (fermented steamed dumplings) have also been developed (Varnashree et al. 2008a, b; Veena et al. 2004).

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Besides the above traditional products, recently small millets are being explored for development of novel food products, which have been shown below: Finger millet Washed and roasted (3min) ground and sieved into flour 25 g flour + 500ml water(solution boiled at 780C and retained for 10 min.) Cooled to 400C 0.031g/L of Lactobacillus casei 431 was added Incubated at 370C for 4 hours Rest ingredients were added and mixed Filled in sterilized glass bottle sealed probiotic beverage

Source: Fasreen et al. (2017). Sheela et al. (2018) has developed fermented curd-like product from five small millets, viz., foxtail millet, little millet, kodo millet, proso millet, and barnyard millet, using the below stated procedure and Fig. 3.6 shows fermented product made from small millet. Small millet Soaked for 16 and 24 hours Germinated in muslin cloth for 24 hours Ground to extract millet milk Filtered Pasteurized and cooled Inoculated with commercial curd culture Incubated at 300 C for 6 hour Fermented curd like product

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Fig. 3.6 Fermented product

3.4

Conclusion

Processing of small millets facilitates to increase their nutritional value by reducing anti-nutritional factors and increase the digestibility and helps in the development of various value-added food products. But owing to its small size, tough outer coat, and husk grain bonding, processing of millet becomes difficult, which is one of the major reasons in decreasing their popularity among producers and consumers compared to their refined counterparts, viz., wheat and rice. The lack of appropriate processing infrastructure coupled with the drudgery involved in manual processing hampers the availability of nutritious small millets in the food basket. However, various processing technologies as described in this chapter can be efficiently adopted to process small millets and in the development of various traditional and novel food items.

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Chilkawar PM, Salve RV, Hashmi SI (2010) Studies on standardization of malting process for finger millet (ragi). Internat J Proc & Post Harvest Technol 1(2):81–86 Chin R, Matlashewski N, Swan K (2012) Development of little millet mill. www.mcgill-ca/bioeng Choudhary M, Das P, Baroova B (2011) Nutritional evaluation of popped and malted indigenous millet of Assam. J Food Sci Technol 48(6):706–711 Coulibaly A, Kouakou B, Chen J (2012) Extruded adult breakfast based on millet and soybean: Nutritional and functional qualities, source of low glycemic food. J Nutr Food Sci 2:151. https:// doi.org/10.4172/2155-9600.1000151 Delost-Lewis K, Lorenz K, Tribelhorn R (1992) Puffing qualities of experimental varieties of proso millet (Panicum miliaceum). Cereal Chem 69(4):359–365 Deshpande HW, Poshadri A (2011) Physical and sensory characteristics of extruded snacks prepared from foxtail millet based composite flours. Int Food Res J 18:751–756 Dharamraj U, Ravi R, Malleshi NG (2013) Optimization of process parameters for decortication of finger millet through response surface methodology. Food Bioproc Tech 6:207–216 Dixit AK, Nanda SK, Singh KP, Kudos SKA (2011) Economic benefits of Vivek millet thresher cum-pearler and agro processing centre in hilly region of Uttarakhand. J Hill Agric 2(2): 177–182 Durairaj M, Gurumurthy G, Nachimuthu V, Muniappan K, Balasubramanian S (2019) Dehulled small millets: the promising nutricereals for improving the nutrition of children. Matern Child Nutr 15:S3. https://doi.org/10.11111/mcn.2791 FAO (1995) Sorghum and millets in human nutrition. FAO Food and Nutrition Series No. 27. FAO, Rome Fasreen MMF, Perera ODAN, Weerahewa HLD (2017) Development of finger millet based probiotic beverage using Lactobacillus casei 431. OUSL J 12(1):128–138 Ganesan S, Varadharaju N (2013) Optimization of machine parameters of centrifugal dehuller for dehulling of foxtail and little millet. Paper presented in the national seminar on recent advances in processing, utilization and nutritional impact of small millets. Madurai Symposium, Thamukkam Grounds, Madurai, 13 September, 2013 Geetha HP, Mathad PF, Nidoni U, Ramachandra CT (2016) Development of foxtail millet based extruded food product. IJFST 6(2):11–22 Geetha R, Mishra HN, Srivastav PP (2014) Twin screw extrusion of kodo millet-chickpea blend: process parameter optimization, physico-chemical and functional properties. J Food Sci Technol 51(11):3144–3153 Hejazi SN, Orsat V (2016) Malting process optimization for protein digestibility enhancement in finger millet grain. J Food Sci Technol 53(4):1929–1938 Kajuna STAR (2001) Millet post—harvest operations INPho-Post harvest compendium. www. fao.org Karthikeyan M (2020) Small scale decentralized processing of small millets. www. vikalpsangam.org Kotagi KS (2011) Little millet (Panicum miliare) flakes: Development, value addition, quality evaluation, consumer acceptability and commercialization. PhD thesis (Food Science and Nutrition), University of Agricultural Sciences, Dharwad Laxmi G, Chaturvedi N, Richa S (2015) The impact of malting on nutritional composition of foxtail millet, wheat and chickpea. J Nutr Food Sci 5:407. https://doi.org/10.4172/2155-9600 Lenkannavar R (2010) Development and quality evaluation of barnyard millet (Echinochloa frumentacea Link) flakes. MSc thesis (Food Science and Nutrition) Thesis, University of Agricultural Sciences, Dharwad Madalageri DM (2012) Fermented product of little millet and application of this technology in catering. MSc (HSc) Thesis, University of Agriculture Sciences, Dharwad Malathi D, Varadharaju N, Gurumeenakshi G (n.d.) Study on nutrient composition of millets and ways to minimize loss during processing and value addition. Project completion report submitted to Agriculture Policy Planning State Planning Commission, Tamil Nadu. www.spc.tn.gov.in

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Malini K, Uthira L, Jaganmohan R (2013) Effect of hydrothermal treatment on the milling characteristics of the tray and shade dried kodo millet (Paspalum scrobiculatum Linn.). Paper presented in the national seminar on recent advances in processing, utilization and nutritional impact of small millets. Madurai Symposium, Thamukkam Grounds, Madurai, 13 September, 2013 Malleshi NG (2003) Decorticated finger millet (Eleusine coracana) and a process for preparing decorticated finger millet. Patent Pub. No. US20030185951A1 Malleshi NG, Hadimani NA, Chinnaswamy R, Klopfenstein CF (1996) Physical and nutritional qualities of extruded weaning foods containing sorghum, pearl millet, or finger millet blended with mung beans and nonfat dried milk. Plant Foods Hum Nutr 49(3):181–189 Mannuramath M, Yenagi N (2015) Optimization of hydrothermal treatment for little millet grains (Panicum miliare). J Food Sci Technol 52:11. https://doi.org/10.1007/s13197-015-1798-z Mir SA, Don Bosco SJ, Shah MA, Mir MM, Ganai SA (2015) Rice: Parboiling and milling properties. Int J Food Eng 11:777–787 Mishra G, Joshi DC, Panda BK (2014) Popping and puffing of cereal grains: a review. J Grain Process Storage 1(2):34–46 Nayak P (2017) Design and development of kodo millet de-husker (roller concave type). MTech. thesis, Jawaharlal Nehru Krishi Vishwa Vidhalaya, Jabalpur Patel A, Parihar P, Dhumketi K (2018) Nutritional evaluation of kodo millet and puffed kodo. Int J Chem Studies 6(2):1639–1642 Patil KB, Chimmad BV, Itagi S (2015) Glycemic index and quality evaluation of little millet (Panicum miliare) flakes with enhanced shelf life. J Food Sci Technol 52(9):6078–6082 Patil RT (n.d.) Advances in processing of food grains. www.authorstream.com Poongodi Vijayakumar T, MohanKumar JB, Jaganmohan R, Janaki A (2010) Effect of pre-milling treatments on characteristics of barnyard millet (Echinochloa colona). Int J Curr Res 2:005–011 Poshadri A (2015) Processing of cereals, Department of Food Technology, Telangana State Agriculture University. www.slideshare.net/poshadri Pradhan A, Nag SK, Patil SK (2010) Traditional technique of harvesting and processing for small millets in tribal region of Bastar. Ind J Trad Knowl 9(4):681–683 Prasad S (n.d.) Millets: processing and utilization.www.ilsi-india.org Rathore S, Singh K, Kumar V (2016) Millet grain processing, utilization and its role in health promotion: A review. Int J Nutr Food Sci 5(5):318–329 Ravindra U, Vijaykumari J, Sharan S, Raghuprasad KP, Kavaloor R (2008) A comparative study of post harvest processing methods for little millet. Trop Agric Res 20:115–122 Saini R, Yadav KC (2018) Development and quality evaluation of little millet (Panicum sumatrense) based extruded products. J Pharmacogn Phytochem 7(3):3457–3463 Sawant AA, Thakor NJ, Swami SB, Divate AD (2013) Physical and sensory characteristics of ready-to-eat food prepared from finger millet based composite mixer by extrusion. Agric Eng Int: CIGR J 15(1):100–105 Sekar S, Mariappan S (2007) Usage of fermented products by Indian rural folks and IPR. Ind J Trad Knowl 6(1):111–120 Shayo NB, Tiisekwa BPM, Laswai HS, Kimaro JR (2001) Malting characteristics of Tanzania finger millet varieties. Food Nutri J Tanzania 10(1):1–3 Sheela P, Uma Maheshwari TM, Kanchana S, Kamalasundari S, Hemlatha G (2018) Development and evaluation of fermented millet milk based curd. J Pharmacogn Phytochem 7(4):714–717 Shobana S, Malleshi NG (2007) Preparation and functional properties of decorticated finger millet (Eleusine coracana). J Food Eng 79(2):529–538 Shrivastava K, Greeshma AG, Srivasatva B (2012) Biotechnology in tradition- A process technology of alcoholic beverages practiced by different tribes of Arunachal Pradesh, North East India. Ind J Trad Knowl 1(1):81–89 Sudha Devi G (2012) Development of extruded products from small millets. M Tech. Thesis (Processing and Food Engineering), University of Agricultural Sciences, Bangalore

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Swami SB, Thakor NS, Gaurav HS (2013) Effect of soaking and malting on finger millet (Eleusine coracana). Agric Eng Int: CIGR J 15(1):194–200 Takhellambam RD, Chimmad BV, Prkasam JN (2016) Ready-to-cook millet flakes based on minor millets for modern consumer. J Food Sci Technol 53(2):1312–1318 Thirumangaimannan G, Gurumurthy K (2013) A study on the fermentation pattern of common millets in Koozh preparation- a South Indian food. Ind J Trad Knowl 12(3):512–517 Tiwari A, Jha SK (2017) Extrusion cooking technology: Principal mechanism and effect on direct expanded snacks: an overview. Int J Food Stud 6:113–128 Ushakumari SR (2009) Technological and physico-chemical characteristics of hydrothermally treated finger millet. PhD Thesis (Food Science). University of Mysore, Mysore Varadharaju N, Ganesan S (2017) Effect of parboiling (thermal treatment) on de-hulling and cooking qualities of little millet (Panicum sumatrense) and foxtail millet (Setaria italica). J Nutr Food Sci 7(3S):56 Varnashree BS, Rao SG, Puttaraj S (2008a) Quality characteristics of ragi (Eleucine coracana) based idli. Ind J Nutr Diet 45:131–136 Varnashree BS, Sowmya JR, Shashikala P (2008b) Quality characteristics of ragi (Eleucine coracana) based idli. Indian J Nutr Diet 45:131 Veena B, Chimmad BV, Naik RK, Malagi U (2004) Development of barnyard millet traditional foods. Karnataka J Agri Sci 17(3):522–527 Wadikar DD, Kangane SS, Parate V, Patki PE (2014) Optimisation of a multi-millet ready-to-eat extruded snack with digestibility and nutritional perspective. Indian J Nutri 1(1):104

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Effect of Processing on Antioxidant Potential and Antinutritional Factors in Small Millets Chhavi Arya

Abstract

Small millets are rich sources of phytochemicals and antioxidants; however, they also contain antinutritional factors. The seed coat of small millets has a unique color and it contains good amount of minerals, vitamins, phenolic compounds, and dietary fiber. The present chapter focuses on the effect of various processing techniques on the antinutritional, polyphenolic, and antioxidant content of millets. Decortication process improves the sensory quality but leads to reduction in minerals, vitamins, fiber, antinutrient, and antioxidant content. In the milling process, there is separation of bran and aleurone layer, which leads to the loss of polyphenols, antinutrients, and antioxidants. Studies have concluded that soaking and germination bring about significant reduction in the polyphenolic and antinutrient content of small millets. During germination process, important biochemical changes occur within the grain, which improve the protein digestibility and mineral bioavailability, and it also reduces the antinutrient content of small millets. Many studies report that the availability of phenolics and antioxidants is improved upon germination; however, contradictory studies are also available. Some free phenolics show a decrease on malting, while the others show an increase. Studies report an increase in antioxidants and a decrease in antinutrients of small millets upon malting. Fermentation of small millets results in higher antioxidant activities and a decrease in antinutritional factors. Roasting of small millets increases the content of phenolic compounds and antioxidant activity. Puffing and popping of small millets lead to a decrease in antinutrients. High retention of antioxidant bioactivities and a decrease in antinutrients in extruded small millets have been reported in various studies.

C. Arya (*) Department of Home Science, DSB Campus, Kumaun University, Nainital, Uttarakhand, India # The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Srivastava (ed.), Small Millet Grains, Cereals, Pulses and Oilseeds, https://doi.org/10.1007/978-981-16-9306-9_4

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Keywords

Small millets · Antioxidants · Phenolics · Antinutrients

4.1

Introduction

The interest in small-seeded millet grains has been rekindled as these are crops that play a beneficial role in combating malnutrition and degenerative diseases and can provide a solution to the world’s problem of food insecurity. Several types of small millets include finger millet (Eleusine coracana), foxtail millet (Setaria italica), kodo millet (Paspalum scrobiculatum), proso millet (Panicum miliaceum), barnyard millet (Echinochloa frumentacea), and little millet (Panicum sumatrense). Millets are widely cultivated in Asia and Africa and are an important part of the poor man’s diet especially that of the rural poor. Millets offer the benefits of being pest-, disease, and drought-resistant crops with short growing period and can be cultivated against the challenges of climate change and low soil fertility, without requiring any heavy agricultural investment (Sahel et al. 2013). Small millets are also known as nutri-grains as these are comparable and even superior to the major widely consumed cereals such as rice, wheat, and maize in several nutritional aspects. Small millets are good sources of carbohydrates, proteins, vitamins, minerals, and dietary fiber. These are also storehouse of several phytochemicals and antioxidants. Phytochemicals (bound phenolic acid, ferulic acid; free phenolic acid, protocatechuic acid), tocopherol, dietary fiber, and carotenoids are found in small millets (Sarita and Singh 2016). The phenolic content of different small millet varieties and grain fractions varies (Liang and Liang 2019). Most often the seed coat and outer layers of the small millet grains are typically colored, which are rich sources of phenols, vitamins, and minerals. Gull et al. (2016) reported that finger millet grain color varied from white to orange. However, other colors of finger millet seed are deep brown and purple to almost red, but the most common is brick red. Finger millet seed coat is a good source of minerals, phenolic compounds, and dietary fiber (Antony et al. 1996). Edible flours of small millets were found to be good sources of endogenous antioxidants with total carotenoid content varying from 78 to 336 μg/100 g in finger, little, foxtail, and proso millet. These millets also showed a higher proportion of γ and α tocopherol. The total tocopherol content was found to be higher in finger and proso millet in comparison to foxtail and little millet (Asharani et al. 2010). Grains of different varieties of millets also contain several antinutritional factors such as phytates, phenols, tannins, and trypsin inhibitors (Antony and Chandra 1998). For a long time, it has only been highlighted that antinutrients such as tannins are responsible for poor protein digestibility of foods containing them, phytates bind minerals, and trypsin inhibitors reduce the digestibility of proteins (Reddy and Pierson 1994). However, currently, the study of phytochemicals, antioxidants, and nutraceuticals is one of the prime areas of research for nutritionist and food scientist. Phytochemicals such as polyphenols and tannins are today valued for their potential

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health benefits such as their role in reducing the tumors and cancer and lowering the risk of heart disease, Alzheimer’s disease, and other degenerative diseases. Study by Chethan et al. (2008) showed strong evidence of the potential of finger millet polyphenols in inhibiting cataractogenesis in humans. According to the “biochemical scavenger theory,” polyphenolic compounds negate free radicals by forming stabilized chemical complexes, thus preventing further reactions. Polyphenols also act against oxidative stress by producing hydrogen peroxide, which helps limit cellular growth (Sroka and Cisowski 2003; Saeidnia and Abdollahi 2013). Evidence from existing research suggests that the colored seed coats of different millet grains are potential sources of different polyphenols having positive health impacts. SubbaRao and Murlikrishna (2002) found that protocatechuic, gallic, and caffeic acid are the major free phenolic acid, whereas ferulic, caffeic, and coumaric acids are the major bound phenolics present in finger millet. Zhang and Liu (2015) analyzed two commonly consumed varieties of foxtail millet and reported that these contained ferulic acid, chlorogenic acid, caffeic acid, p-coumaric acid, syringic acid, and carotenoids. Zhang et al. (2014) reported that proso millet is rich in bioactive phytochemicals including ferulic acid and chlorogenic acid, syringic acid, caffeic acid, and p-coumaric, which are beneficial for humans. Kodo millet is reported to have a good DPPH quenching capability (Hegde and Chandra 2005). Among the different types of small millets, kodo millet showed the highest total phenolic content, while it was the least for proso millet. However, all millet varieties showed high antioxidant activities (Chandrasekara and Shahidi 2010). Multitude of investigations on small millets prove that these are rich sources of polyphenols and antioxidants and therefore have several benefits for human health. Small millets are generally subjected to various processing methods before being consumed as food. Some common traditional methods used for processing millets are decortication, grinding, milling, sieving, soaking, fermentation, malting, roasting, puffing, flaking, and cooking. In addition to having an impact on the sensory properties of millet grains, these processing methods also affect the nutritive value, bioavailability of nutrients, and antinutrient and polyphenolic content of the processed millet. The present chapter focuses on researches on processing techniques to which millets are subjected and the effect of various processing techniques on the antinutritional, polyphenolic, and antioxidant content of small millets. Some of the processing methods of small millets and their impact on grains are as follows.

4.2

Decortication

Decortication or dehulling of millet refers to the removal of their outer coverings such as husk and bran from the small seeds. The process is generally applied to millets to remove the fibrous seed coat and other substances, which could lead to a low sensory quality of the product. There are two types of seeds in millets, namely, utricle and caryopsis. In utricle, the pericarp surrounds the seed like a sack. Finger, proso, and foxtail millets are utricle. The pericarp of finger millet is membranous and

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loosely attached with the seed at maturity. Testa of finger millet is five layers, and the inner layers of the testa contain tannins while the outer layer contains phenolics (McDonough et al. 1986). In caryopsis, the pericarp is completely fused to the seed coat as in fonio millet. The seed type and structure need to be considered before selecting the decortication process. Owing to the small size of most millet grains, it becomes slightly difficult to decorticate or dehull them in a fashion similar to the popular grains. Though the decortication process improves the sensory quality, it also leads to a decrease in the nutrient content, mainly minerals and vitamins. Removal of the bran layers reduces the fiber, antinutrient, and antioxidant content. Histochemical examination of finger millet grain, seed coat, and endosperm portions for polyphenolic content revealed that almost 90% of the polyphenols are positioned in the seed coat tissue (Chethan and Malleshi 2007). Minerals, fiber, antioxidants, and antinutrients are mainly sited in the peripheral parts of the grain (pericarp and aleurone layer); therefore, the removal of these layers during decortication leads to reduction in their content (Hama et al. 2011). Bagdi et al. (2011) concluded that decortication of proso millet and two commercially available millets did not affect their protein and fat content; however, it significantly decreased the dietary fiber, total phenols, and antioxidant capacity. Hence, decortication of these millets decreased their applicability as functional food. Chandrasekara et al. (2012) in their study on millets reported that the phenolic content and antioxidant potential of millet grains were affected by dehulling and hydrothermal treatments. They observed that in general the antioxidant activity of phenolic extract was the highest in the hulls followed by whole grain, dehulled grain, and lastly cooked dehulled grain. Parboiling is traditionally used in the case of paddy to improve the head rice yield as well as nutritional value. The same technique can also be used in the case of millets. Bora et al. (2019) reported that parboiling resulted in a significant rise in free and bound phenolic content and DPPH radical scavenging activity of millet products and concluded that phenolic and its antioxidant activity increased in products from parboiled millets.

4.3

Milling

Milling is the most important processing treatment, which is applied to most cereals and millets. The primary objective of milling process is to separate the floury endosperm from the bran and germ. Generally, cereals and millets are subjected to cleaning process before being milled. The milling process includes grinding, sieving, and separation of the bran and gritty parts. The process is repeated to further reduce the particle size. Most millet grains are milled and converted into flour before being used. Several food products can be formulated from millets only after they are milled. Milling has several advantages with respect to grain utilization as it improves the taste, flavor, acceptability, and digestibility of the grain. However, milling of millets leads to the removal of the bran and the germ layers that are rich in fiber and phytochemicals (Amadou et al. 2013c). In the milling process on account of sieving, there is separation of bran and aleurone layer, which

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leads to a considerable loss of polyphenols, antinutrients, and antioxidants. As the antioxidant components of whole grains are mainly located in the cortex, aleurone layer, and germ part, the milling process inevitably adversely affects the polyphenols and their antioxidant activities (Tian et al. 2019). Studies report that moist conditioning of millets prior to milling reduces fragmentation of the seed coat during milling and therefore helps produce more refined flour (Malleshi et al. 2004). Since more of bran is removed on moist conditioning of the grain, it can therefore be concluded that conditioning operations when applied prior to milling lead to further reduction in the polyphenolic content of the flour. Traditionally, in Asian and African countries where millets are consumed, they are generally ground using mortar and pestle, burr or hammer mills, and stone hand grinders or chakki. Traditional milling methods used for milling small millets are time and labor intensive. In the present times, modern milling machines are also used to pulverize millets. However, they are not specifically designed for milling small millets. Roller mill setups are designed for milling wheat and need to be modified for milling millets (Malleshi et al. 2004). In India, finger millet grains are milled with testa to prepare whole grain flour, which is generally rich in dietary fiber and micronutrients. The preparation of traditional Indian finger millet–based recipes does not require fine milling and sieving. Some recipes such a thin porridge can also be prepared by utilizing slightly gritty flour. Thus, substantial amount of bran remains in the flour, and therefore, the polyphenol and antioxidant content of such flour increases. Daily consumption of whole grains of finger millet and its products can protect against the risk of several diseases (Chandra et al. 2016).

4.4

Soaking and Germination

Some millet-based food products and recipes require prior soaking and germination of the millet grains. Even for accomplishing the processes of germination and fermentation, millets require prior soaking. Both soaking and germination bring about changes in the chemical composition and nutritive value of the grain. Various studies conclude that soaking and germination bring about significant reduction in the polyphenolic content of commonly consumed millets (Naveena and Bhaskarachary 2013). Soaking millet grains also reduces the antinutrients present in the grains. As a result of the germination process, important biochemical changes occur within the grain. From a dormant state, the seeds become fully viable, and as a result of the biochemical processes taking place within the grain, its nutritional profile is altered and improved in several respects (Benincasa et al. 2019). In edible food grains as a result of germination process, the content of free amino acids, total sugars, and B vitamins increases. It also improves protein digestibility and mineral bioavailability. Germination process brings about a reduction in the antinutrient content of seeds. During germination, the activities of hydrolytic enzymes increase, which bring about an improvement in the content of essential amino acids, total sugars, and B group vitamins and decrease dry matter, starch, and antinutrients

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(Dipnaik and Bathere 2017). Cereal type, quality of seed, and sprouting conditions have their impact magnitude of nutritional improvement (Chavan and Kadam 1989). Seed soaking time, germination time, and temperature affect the phenolic and dietary fiber content of millets. However, with regard to the changes in antinutritional factors upon germination, there is consensus that these decrease significantly. Several complex reactions occur in the germinating seeds. Many studies report that the availability of phenolics and antioxidants is improved upon germination. Sharma et al. (2015) reported that with the increase in soaking time, germination time, and germination temperature, antioxidant activity, total phenolic content, and total flavonoid content of foxtail millet increased significantly. The study showed that germination increased the availability of bioactive compounds such as total phenolics, antioxidants, total flavonoids, protein, dietary fiber, and minerals and lowered antinutritional factors. Sharma et al. (2016) from their study concluded that optimized germinated barnyard millet flour had a higher nutraceutical content than the raw barnyard millet flour. Free, bound, and total phenolic content increased significantly in germinated barnyard millet flour. The concentration of phenolic compounds in barnyard millet seeds increased due to cell wall –degrading enzymes, which became active during germination, and modified cell wall structure of the grain. It was also reported that antinutrients, tannin and phytate, decreased significantly on germination and that germinated small millets can be utilized in product development and also for the extraction of valuable compounds. Pradeep and Sreerama (2015) from their study on barnyard, foxtail, and proso millet concluded that in comparison to steaming and microwave treatment, germinated millet exhibited the highest phenolic content along with superior antioxidant and enzyme inhibitory activities. Sprouting provided more bioaccessible phenolics. Sprouting of finger millet resulted in lower antinutrient levels, namely, tannins, phytates, and trypsin inhibitors, and therefore, in vitro protein digestibility and HCl extractability of minerals and trace elements were improved (Mwikya et al. 2000). Sharma et al. (2018) in their study reported that germination together with ultrasonic-assisted extraction brought about a significant desirable effect on the characteristics of polyphenolic component, on GABA content, and in in vitro antioxidant capacity of foxtail millet flour extracts. They reported increase in total antioxidant activity and reducing power, DPPH and hydrogen peroxide scavenging activity, metal-chelating abilities, and in vitro antioxidant activity upon germination. Metal-chelating abilities and in vitro antioxidant activity enhanced due to increase in phenolics, flavonoids, and GABA content. Synthesis of additional phenolic components as a result of germination was also reported. As an effect of the germination process, a comparatively higher increase in phenolic content was reported in finger millet in comparison to pearl millet (Chauhan and Sarita 2017). However, Singh et al. (2017) reported that germination results in maximum reduction of polyphenolics in finger and other millets. The reduction in polyphenols during germination was attributed to activation of phenolic oxidase and amylase and also to their leaching to some extent.

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Malting

Malting is yet another processing treatment applied to cereals and millets. In the case of millets, it is generally used in the brewing industry and also for preparation of weaning foods. For preparing malt, millet grains are soaked for some time. Thereafter, the grains are removed from soaking water, and they are left to sprout in a moist and hydrated condition. After the grains have sprouted, they are dried followed by the process of removal of rootlets by rubbing them. The grains are then ground to fine particles and sieved to obtain malt flour (Chilkawar et al. 2010). Malting results in the mobilization of potential seed enzymes such as amylases, proteases, etc., which hydrolyze and modify the grain components and its structure (Macleod and Evans 2016). Among cereals and millets, malting of barley is most common and is done on a commercial scale. Finger millet is also well suited for the preparation of traditional malted infant food. Upon malting, the nutrient content and digestibility of the grains are improved. However, in finger millet, the major free phenolic acids are protocatechuic, gallic, and caffeic acids. A study reported that on 96 h of malting, protocatechuic acid content decreased threefold, whereas caffeic acid decreased slightly. Interestingly, free phenolic acids mainly, gallic acid, vanillic acid, coumaric acid, and ferulic acid increased. Major bound phenolics such as ferulic, caffeic, and coumaric acids decreased on malting for 96 h. It was noted that free phenolic acid mixture showed a higher antioxidant activity compared to that of bound phenolic acid mixture indicating that the antioxidant capacity of phenolic acids is altered through the malting process of ragi (SubbaRao and Murlikrishna 2002). In another study by Udeh et al. (2018), catechin, epicatechin, quercetin, taxifolin, and hesperidin were the isolated flavonoids in finger millet malt. In the study, it was observed that catechin, epicatechin, and protocatechuic acid increased upon 72–96 h of malting of brown finger millet. On the other hand, there was a total loss of taxifolin and hesperidin for the same malting duration. Finger millet malt also exhibited antioxidant activities, which increased with malting period for iron-reducing activity. The study concluded that varietal differences play important roles in how malting affected phenolic compounds. Hejaji and Orsat (2016) reported that malting reduced the phenolic content of finger millet by 25%. Malting decreased tannins up to 54% in brown finger millet (Ramchandra et al. 1977).

4.6

Fermentation

Fermentation is another processing technique applied to small millets for the preparation of several food products. Across Asia, Europe, and Africa, small millets are subjected to fermentation to prepare pancakes, leavened breads, and alcoholic beverages such as beer and wine. Several traditional recipes such as idli, dosa, adhirasam, etc. are prepared by fermenting millets in coarsely ground or in flour form. Traditional millet-based alcoholic beverages like tongba and boza are produced in countries like Nepal, Romania, and Bulgaria. Attempts have been made by

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Shashi et al. (2007) to prepare wine from finger millet. Small millets are also utilized for the production of leavened fermented breads. Attempts have also been made to prepare yeast-leavened composite finger millet and foxtail millet breads by Chhavi and Sarita (2012). Yeast is the main microorganism responsible for bread production; however, lactic acid bacteria are used for the production of rye sour breads. Fermentation process is brought about by suitable microorganisms under conditions favoring their growth. Fermentation improves the nutritive value of the food product, increases protein digestibility, and decreases the antinutrients present. Antony and Chandra (1998) found that fermentation of finger millet flour exhibited a significant decrease in phytate, phenols, tannins, and trypsin inhibitor activity by 24 h. However, mineral availability, in vitro protein digestibility, and in vitro starch digestibility were enhanced. Sripriya et al. (1997) subjected finger millet to germination for 24 h and then to fermentation for 48 h, as a result of which the phytate content decreased by 60% and HCl extractable minerals increased by 47%. In a study aimed to evaluate the impact of process-induced changes on phenolic profiles of finger millet sour porridge, it was found that fermentation and cooking brought about a twofold increase in the phenolic compound, condensed tannin, and individual phenolic compound in finger millet (Gabaza et al. 2016). The high antioxidant activity exhibited by millet koozh (traditional fermented millet beverage) was attributed to the use of finger millet in its preparation (Anand 2017). A study by Amadou et al. (2013a) attempted to investigate the antioxidant properties of water extracts from fermented (solid-state fermentation by Lactobacillus paracasei Fn032) foxtail millet flour and its bran with and without protease. Fermented foxtail millet flour with added protease showed a higher scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals and reducing power than fermented foxtail millet flour and bran extract without added protease. The study concluded that fermented foxtail millet is a good source of bioactive peptides with significantly higher antioxidant and antimicrobial activities. A remarkable antioxidant activity was associated with potential activity of L. paracasei Fn032 during bioprocessing. Fermented foxtail millet meal is a good source of natural antioxidants. Foxtail millet meal fermented by L. paracasei Fn032 was subjected to purification by HPLC and amino acid sequencing (by LC-MS). Purified foxtail millet peptide fractions of tyrosine/leucine rich showed significant scavenging activities for DPPH and superoxide anion radicals (Amadou et al. 2013b). The addition of a single strain of L. acidophilus reduced antinutritional factors (Pampangouda et al. 2014). In vitro enzymatic digestion and microbial fermentation was applied to dehulled and cooked grains of small millets, viz., kodo millet, finger millet, proso millet, and foxtail millet. Results showed that all small millets exhibited effective antioxidant activity and that phenolic compounds of processed millets were bioaccessible. Phenolics bound to the insoluble fiber in the grain were released on colonic fermentation (Chandrasekara and Shahidi 2012). Germination and fermentation processes could bring about an increase in the antioxidant properties, owing to enhanced antioxidant content, viz., phenolic compounds (Liang and Liang 2019).

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Roasting

Roasting of cereals, millets, or even pulses is a simple technique practiced mostly in tribal and rural areas since a long time. As a result of dry roasting, the moisture content and the antinutritional factors present in the grains decrease. It also results in the development of pleasant acceptable flavor of the grain. Majority of the existing studies report that roasting results in an increase in the bioavailable polyphenolic content. Sand roasting of small millets has been traditionally carried out in India. Srivastava and Batra (1998) reported that among minor millets (finger, foxtail, barnyard, and proso millet), the highest popping yield and expansion volume were obtained for proso millet. The content of secondary compounds and the antioxidant properties of proso millet significantly increased upon roasting. A study reported that significantly the highest content of total phenolic (670 mg/100 g of ferulic acid equivalent) and total flavonoid (391 mg/100 g of rutin equivalent) was attained in roasted proso millet followed by steaming, puffing, and extrusion. Chromatographic analysis exhibited a higher amount of single phenolic acids such as syringic, gallic, 4-hydroxybenzoic, ferulic, and sinapic acids and catechin in roasted proso millet in comparison control (Azad et al. 2019). Pradeep and Guha (2011) reported that total phenolic, flavonoid, and tannin content increased maximum during roasting compared to germination and steaming and that roasted little millet showed the highest radical scavenging activity and ironreducing power. Roasted millets showed a higher antioxidant capacity because of the breakdown of cellular constituents and membranes and also because of the Maillard reaction leading to the formation of different intermediate products (Vaher et al. 2010). Hithamani and Srinivasan (2014) concluded that sprouting and roasting of finger millet and pearl millet provided more bioaccessible phenolics. Fei et al. (2018) studied the influence of roasting on antioxidant activity and phenolic content of proso millet and identified nine individual phenolic compounds in roasted proso millet with p-coumaric acid and trans-ferulic acid as the major phenolic acids in the free fraction and vanillic acid and p-coumaric acid in the bound fraction. It was also found that roasting increased the content of phenolic compounds and antioxidant activity. Microwave roasting of barley resulted in a mixed response toward its antioxidant potential. The percentage inhibition of DPPH and reducing power increased, while all the other parameters such as radical scavenging activity and total phenolic content showed a decrease (Baba et al. 2016).

4.8

Popping and Puffing

Popping and puffing are traditional processing methods applied to millets to convert them into a crispy ready-to-eat product. Popped or puffed cereals and millets are considered to be healthy snacks and are popular. Popped millets are used as an afternoon snack. In popping process, exposing the grains to a high temperature for a short duration results in heating of the kernel. The moisture present in the kernel is

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converted to superheated vapor, and pressure is generated within the kernel, causes it to explode, and allows the steam to escape. In this process, the kernel is exposed inside out and gelatinization of starch takes place (Mishra et al. 2014). The most commonly popped cereal is corn. In traditional puffing, the cereal grains (most often parboiled rice) are subjected to a high temperature for a short time. The process includes throwing the rice in sand heated to a high temperature. When the grains are stirred, they begin to crackle and swell. Contact of the grain with intense heat results in deformation and phase transition within the grain, as a result of which the grain structure becomes porous and expanded. During puffing, properties like degree of gelatinization, glass transition temperature, nutrient content, and porosity and microstructure of the grain are changed (Saha and Roy 2020). As processing methods, popping and puffing impact the nutrient, antinutrient, and phenolic content of the millets. Popped grains have a highly desirable aroma as a result of the Maillard reaction, which occurs during the process. Puffed grains are also ground to powder form for consumption (Kakade and Hathan 2015). Limited research has been attempted to study the impact of puffing and popping on the polyphenolic content of small millets. Michael and Vinson (2019) in their study showed that popcorns contain significant amount of antioxidants known as phenolic acids, and results of their study further indicated that a considerable amount of bound polyphenols become bioaccessible on popping, and therefore, popcorn may be a significant source of dietary polyphenol antioxidants. There seems to be consensus through several researches that puffing and popping processes bring about a reduction in antinutrients of the grains. Puffed finger millets have been traditionally used in India as ready-to-eat food. Wadikar et al. (2006) reported that puffing of finger millet resulted in 21 to 50% reduction of phytic acid, while reduction of tannins was 3–8%. In the hilly varieties, a decrease in tannin content during puffing was less in comparison to base/plains region varieties. Chauhan and Sarita (2018) reported a lower tannin (610 mg/100 g) and phytic acid (333.1 mg/100 g) content in popped finger millet flour than whole finger millet flour. The study also concluded that antinutrients such as oxalic acid and trypsin inhibitor activity decreased after popping; however, iron content increased significantly on popping. Total polyphenolic content of puffed proso millet was 0.98% (Pilat et al. 2016).

4.9

Extrusion Cooking

Extrusion cooking uses a high temperature and short time for the development of food products such as cereal-based snacks, breakfast cereals, baby foods, and other textured foods (Sebio and Chang 2000). Extrusion process is being increasingly used in the food processing industries. The process is a combination of various operations such as mixing, shearing, heating, pumping, forming, and sizing. In this process, the mixed ingredients are forced through a die, and the forced product is then cut to size. There are ambiguous effects of extrusion cooking on nutritional quality of expanded snacks such as the destruction of antinutritional factors, increased soluble dietary fibers, and reduction in lipid oxidation and microorganisms (Tiwari 2018). The

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bioactive compounds in extruded products are influenced by extrusion process variables such as shear, temperature, resonance, time, and water content. Food structure may also exhibit a role in the potential release of functional bioactives (Brennan et al. 2011). Kaur et al. (2015) in their study on components of cereal brans concluded that extrusion processing reduced the phytic acid content by 54.51%, polyphenol by 73.38%, oxalates by 36.84%, and trypsin inhibitor by 72.39%. Heat treatment caused the highest reduction in polyphenols followed by trypsin inhibitors, phytic acid, and oxalates. A ready-to-eat snack produced from rice, finger millet, and horse gram (40,50,10) by extrusion process showed a significantly higher total phenolic content (465.23 mg GAE/100 g dw) and antioxidant activity (17.98 μmol TE/g dw) than market samples (Patil et al. 2017). Extrusion treatments resulted in a significant decrease of total phenolic content, total flavonoid content, and antioxidant activity of extruded finger millet over native counterpart. However, extrusion at high feed moisture, low temperature, and high screw speed retained a considerable percentage of bioactives. High retention of bioactives in extruded millet flours showed great potential for the development of phenolic- and antioxidant-rich ready-to-eat snacks (Patil et al. 2016). A study by Gulati et al. (2016) exhibited that high expansion and antioxidant activity can be attained by extruding proso millet under low moisture and high screw speed conditions. Kodo millet–chickpea flour blend (70,30) was used for the development of directly expanded snack by twin screw extrusion. Acceptable crispy extrudates were attained at a higher screw speed (293 rpm), lower feeder speed (19 rpm), and medium high temperature (123  C) (Geetha et al. 2012). Millet pomace–based pasta containing 20% finger millet along with other ingredients had significantly a higher phenolic content and antioxidant activity than control (Gull et al. 2018).

4.10

Conclusion

Small millets are storehouse of antioxidants and phytochemicals. Edible flours of small millets are good sources of antioxidants, phytochemicals, and dietary fiber; however, they also contain several antinutritional factors. Antioxidants and phytochemicals are receiving much attention of scientists as these play a beneficial role in several degenerative diseases and also reduce oxidative stress. Various processing methods to which millets are subjected to affect their antioxidant, polyphenol, and antinutrient contents. Processing method such as decortication results in removal of bran layers and leads to a reduction in the antioxidant content. Most small millets are milled to flour, and in this process, particle size is reduced and they are sieved that further decreases the antioxidant potential and antrinutrients present. Moist conditioning operation before milling leads to a reduction in polyphenolic content of flour. Studies conclude that a processing method such as soaking brings about a reduction in polyphenolic and antinutrient content of small millets.In germination process, the antinutritional factors decrease significantly. Many studies report that availability of phenolics and antioxidants improves upon germination,

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which is mainly because of the fact that cell wall–degrading enzymes become active during germination. However, few studies show a decrease in polyphenols on germination. Varietal differences and malting time play a role in how malting affects phenolic compounds. It has also been reported that malting decreases phenol and antinutrients of millets; however, there is room for research on this aspect. Fermentation of small millets results in higher antioxidants activities and decreases antinutritional factors. Majority of the existing studies report an increase in bioavailable polyphenolic and antioxidant content on roasting. Puffing and popping of small millets led to a decrease in antinutrients. Limited studies are available on the impact of puffing and popping on polyphenolic and antioxidant content of small millets. High retention of antioxidant bioactivities in extruded small millets has been reported in various studies; however, in the same process, a decrease in antinutrients has also been observed.

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5

Small-Millet-Based Traditional and Unconventional Food Products Anju Bisht

Abstract

Small millets have been a part of staple diet especially in Asian and African continents. Despite the limitations in processing, small millets are being utilized to prepare traditional food products and beverages. Small millets have been used to prepare traditional food items like porridge, gruel, fermented and unfermented flatbreads, dumplings, and alcoholic and non-alcoholic beverages, though their processing and preparing techniques vary from place to place. With the passage of time, the popularity of small-millet-based traditional food products and beverages has been devalued, probably due to fascination for refined grains, drudgery involved with processing of small millets, and also lack of documentation of traditionally prepared small-millet-based recipes. However, recently, with the realization of nutritional and health benefits of small millets and development of standardized processing techniques, they are being used to prepare unconventional food products and drinks. The unconventional food items, like ready-to-eat (RTE) mixes, ready-to-cook (RTC) mixes, snacks, novel baked and extruded products, etc., have been prepared which not only add to the variety in food basket but also provide health benefits along with sustenance to hunger for the growing population. Presently, there is a need not only to popularize small-milletbased traditional food products but also to develop small-millet-based valueadded food products. Keywords

Small millets · Traditional food products · Conventional food products

A. Bisht (*) Department of Home Science, MB Government PG College, Nainital, Uttarakhand, India # The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Srivastava (ed.), Small Millet Grains, Cereals, Pulses and Oilseeds, https://doi.org/10.1007/978-981-16-9306-9_5

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5.1

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Introduction

Small millets termed as coarse cereals are known to be one of the oldest cereals grown and consumed throughout the world. They are believed to be the first domesticated cereal grains. They were first grown in Asian and African continent almost 7000 years ago and gradually spread to other parts of the world. There are evidences to show that millets were cultivated for human food and fodder in Korean peninsula around 3500–2000 BC. In India, the consumption of millets is predated to Indian Bronze Age, i.e. 4500 BC, in China since 2800 BC and in Egypt since 3000 BC. Today millets are ranked as the sixth most important cereal sustaining one-third of world’s population (www.icrisat.org; www.edenfoods.com). Unfortunately, with the passage of time, refined cereals, such as rice, wheat, and maize, started gaining popularity over these coarse cereals, and cultivation and consumption of small millets declined in many parts of the world. These climate-resilient and nutritionally rich small millets took the back seat in the staple diet. Recently, with the research substantiation, these coarse cereals are recognized as nutritionally superior and hardy crops compared to their refined counterparts and have been now termed as nutri-cereals. With time, policy makers, consumers, and producers have also realized that it is profitable to invest in these super crops as they are not only a feasible solution to attain food and nutrition security but also a solution to degenerative diseases and are economically viable opportunity for farmers. Although there have been ups and down in the production and consumption of small millets, small millets have been habitually utilized for making traditional food products by some segment of the population. Furthermore, in recent years, significant work has been done to develop small-millet-based unconventional food products with therapeutic properties. This chapter discusses the traditional and unconventional food products based on small millets.

5.2

Small-Millet-Based Traditional Food Products

Small millets have been traditionally consumed in developing countries of Asia and Africa. India, China, and Myanmar are major consumers of millets in Asian region. Among African countries, namely, Niger, Mali, Nigeria, Burkina, and Sudan, are the major global consumer (40%) of millets (www.agriexchange.apeda.gov.in). It has been estimated that more than 90 million people in Asia and Africa depend on millets for their diet (www.icrisat.org). Millets are produced by 28 countries of African continent sustaining 130 million people in Sub-Saharan Africa. Of the total produce, 78% is consumed as staple food, 20% as drinks and other uses, and 2% as feed. Basically, flour, meal, and malt of millets are used for preparing indigenous foods and drinks (Obilana 2003). Over the centuries, millets have been used in regional dishes and have become engrained in culture. Small millets have been traditionally used mainly in the form of porridge, gruel, and beverages. Whole millet grains are also traditionally eaten in the form of rice and popped or puffed grains. The flour is used to prepare fermented and

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unfermented flatbreads, dumplings, porridge, and gruel. Alcoholic and non-alcoholic beverages are also made from millets since old times (Taylor and Emmambux n.d.). Traditionally eaten millet porridge and gruel differ in consistency, flavour, and nature like being alkaline or sour because of their processing and preparation techniques which differ from place to place. For instance, Russian millet porridge is sweet, prepared by addition of milk and sugar, whereas Chinese millet porridge is made by adding squash, beans, and sweet potatoes; on the other hand, in Namibia, porridge is known as Oshifima which is simply made by hand pounding and swallowing it without chewing (www.fao.org; Scott 2015). In Korea, porridge is prepared by boiling in water and adding honey and egg to it, and in Italy, Polenta, a porridge or mush-like dish and pannisa risotto–like dish (grains cooked in stock with vegetables, meat, or seafood), is made traditionally from proso millet. In Germany, it is reported that proso millet is used to make porridge with added apples and honey (Das et al. 2019). Couscous is a steamed cooked porridge, bouillie is thin porridge, tuwo is thick or stiff porridge, ogi and koko are fermented thin porridge, and ily is lemon soured porridge (Obilana 2003). Nsima, mafo, sadza, ugali, mosokwana, tuo, boule, and bita are local names of some traditionally made neutral pH stiff porridge in various parts of African continent. They are made by cooking millet flour in plain water without adding any additive. In some traditional method of preparing porridge, the millet flour is soured and fermented for few hours (at least 8 h) before cooking which results into fermented porridge (Kajuna 2001). Ben-saalga, bushera, and togwa are fermented gruel; fura, koko, and uji are fermented porridge, and kunuzaki and ogi are fermented paste (Amadou et al. 2011). In Asian countries, small millets are traditionally consumed in the form of bhat which is a type of boiled rice, mudde (dumpling and stiff porridge), roti (unfermented flatbread), kheer (sweetened dessert made by adding sugar, milk, and clarified butter), ambli (a thin gruel consumed as breakfast drink), dosa (a fermented pancake), shavige (noodle), huri hittu (popped grain flour), and sattu and halwa (cooked sweet product) (Seetharam and Gowda n.d.). The whole small millet grains (foxtail and proso) are fried, or its flour is consumed after mixing with molasses (jaggery) and salt or consumed as rice or flattened bread (roti) in Bangladesh. Small millets are also used to prepare payesh or firney. It is a sweet product prepared by cooking dehusked foxtail millet (FoM) grains with milk and sugar (Majid et al. 1986). In Sri Lanka, small millet especially proso millet is traditionally used to make string hoppers, pittu, flattened bread (roti), and porridge. To the porridge prawns, vegetable or rice is added before consumption, and while making roti or pittu, coconut scrapings are added (Ponnuthurai 1986). Small millets with malting potential are traditionally used to prepare beer, and millets with low malting potential are used to prepare porridge and flatbreads (Obilana 2003). Mangisi is a sweet-sour beverage made from naturally fermented millet mash, and masvusvu is a sweet beverage made from unfermented millet (Amadou et al. 2011). Millets have been traditionally used to prepare alcoholic beverages by fermentation in various countries like Boza in Romania and Bulgaria;

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Tongpa in Nepal; Rakshi, Marcha, Themsing, Lohpani, Mingri, and Sur in various states of India; and Jiu in China (Das et al. 2019). Preparation details of food products and beverages based on small millets which are traditionally prepared and consumed by people in Europe, Africa, and Asia are given below.

5.2.1

Food Products

Kasha is a porridge made from proso millet groat (known as psheno in Russia). It is prepared by boiling proso millet groat in water or milk to prepare porridge (Das et al. 2019). Migliaccio is a traditional dish made from proso millet in Italy. It is a type of cake prepared from millet, hog blood, chocolate, and milk (Das et al. 2019). Samaipaysam is a sweet product which is made from little millet (LM). Millet is stirred in boiling water and then jaggery, fennel powder, and groundnut powder are added, and it is cooked on low flame (Kumar et al. 2018). Korramurukulu is an extruded snack item made from mixture of foxtail millet and Bengal gram flour to which spices like cumin seeds, chilli powder, sesame seeds, and salt are added and kneaded into a stiff dough which is then hand extruded and deepfried (Kumar et al. 2018). Enjera is a type of pancake made from teff. The teff grains are wet ground followed by fermentation and finally baked on hot pan to make pancakes. It is a popular food item of Ethiopia (Malleshi 1986). Ugali is a stiff porridge made from finger millet (FM). It is also known as ikeille and to in different parts of Africa (Kubo 2016). The millet is mixed with cassava or sweet potato or sorghum and ground into flour. The flour is mixed with water until it becomes stiff to form Ugali. Ugali is eaten with vegetables, groundnuts, sesame, meat, or chicken. In some places, it is eaten as a complete meal and served to guests, and in some places, it is a minor meal served to pregnant and lactating women and children (Esele 1986). Uji is thin porridge made by fermentation of cereal mixes containing millet (finger millet). Its preparation method is almost like ugali, only that more amount of water is used. It is consumed as weaning food by the infants and as beverages by adults for breakfast (Kubo 2016). Idiyappam, also known as putu mayam in Malaysia, putu mayang in Indonesia, and string hoppers in English, is a traditional dish of south India and Sri Lanka made from small millets. Proso millet or finger millet flour is mixed with salt, seasonings, and water and kneaded into dough. The dough is filled in a press machine (sieve like) and pressed onto a banana leaf or directly in steamer for 5–10 min and served with coconut dip (Ponnuthurai 1986). Ogi is a fermented soft porridge made from millets and eaten as traditional breakfast food. Whole grains are soaked for 2–3 days, washed, crushed, and sieved. The sieved product is allowed to ferment, water is decanted, and solids are cooked in freshwater or in decanted water to prepare ogi (Kajuna 2001).

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Sadza is porridge with thick consistency. Finger millet flour is added to boiling water to obtain a thick consistency and then finally served with meat, vegetable, or milk. This is a traditional food of Zimbabwe preferred for pregnant women (Muza 1986). Injera is traditional fermented bread made from teff millet or finger millet. First, flour is fermented for about 48 hours. And then, a fresh batch of flour is gelatinized by adding boiling water and added to fermented batter which is then baked to make bread (Kajuna 2001). Dosa is a fermented pancake popular in Southern India and Sri Lanka. Dehulled small millet grains are soaked, wet milled, and fermented overnight. Batter is poured and spread on hot metal plate greased with oil and cooked from both sides. Massa and galettes are also types of fermented pancakes made from millet and consumed occasionally (Kajuna 2001). Roti is an unfermented pancake made from millets and eaten as staple food item in India. Millet (finger millet) flour is kneaded with water. Small balls are made and pressed into circular sheets and baked on hot metal. It is consumed with vegetables, curd, milk, or dal (Kajuna 2001).

5.2.2

Beverages

Small millets have been traditionally utilized for preparing alcoholic and non-alcoholic beverages. Sur is a finger-millet-based fermented beverage. The millet flour is kneaded with water to make dough which is left in container for 7–8 days for natural fermentation. The fermented flour is half baked into rotis (rolled into round, flatbread) which are cut into pieces and allowed to ferment by adding dhaeli (local herbs), jaggery, and water in a smoke-treated earthen pot for 10 days. After completion of fermentation, liquid is filtered. It contains 5–10% of alcohol (Kumar et al. 2018). Madua is a finger-millet-based alcoholic beverage. Millet is roasted and cooled until soft. The softened grains are allowed to ferment for 4–7 days. After completion of fermentation, hot water is poured and collected in a container. The collected liquid is madua (Kumar et al. 2018). Koozh is a fermented beverage made from finger millet and pearl millet. Millet flour is made into slurry with water and allowed to ferment overnight. Then broken rice is cooked in excess water to which slurry is added and cooked to make porridge, which is further allowed to ferment to obtain a semisolid porridge. To the porridge, water is added and hand mixed with addition of salt to prepare koozh (Kumar et al. 2018). Jandh is a slightly acidic and sour alcoholic beverage made from finger millet. The grains are steamed and spread, on to which murcha starter culture is sprinkled, mixed, and kept for 24 h at ambient temperature. Then they are placed on earthen pot and covered with leaves and allowed to stand for fermentation. After the fermentation, the seeds are hand processed to remove seed coat. The grits are then placed on bamboo vessel with water and the drink is ready after 10 min (Amadou et al. 2011).

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Masvusvu is a sweet unfermented beverage made from malted finger millet. Mixture of malted millet meal and water is heated in earthen pot and stirred slowly for a period of 80 minutes. When the slurry thickens, the product is ready to consume (Amadou et al. 2011). Mangisi is a sweet-sour fermented beverage made from finger millet malt which is mixed with water. The mixture is slowly heated for 80 min to obtain mash known as masvusvu which is collected, diluted, strained, and allowed to stand for several hours for spontaneous fermentation to produce mangisi. Another variation to make mangisi with more alcohol content is by adding extra malt to masvusvu, and the mix is allowed to ferment for 3 days. Coarse solids are strained off and mangisi is ready to consume (Amadou et al. 2011). Togwa is a saccharified beverage, prepared with finger millet, sorghum, maize, and banana. The preparation techniques and ingredients may vary from place to place. Maize flour and sweet potato are boiled in hot water and then cooled to 70 C (approx.), after which germinated finger millet is added and slurry is mixed vigorously. This mix is then allowed to stand for a day. It serves as instant energy drink for adults and weaning food for children as it is energy dense and easily digestible (Kubo 2016). Amadou et al. (2011) have also documented the preparation of togwa. The fermented beverage made from finger millet malt and maize flour is prepared by cooking the flour mix in water. Further it is cooled and old togwa and flour from germinated grains are added. Fermentation is allowed and resulting product is consumed. Suutei Tsai is a Mongolian tea made from millet, milk, salt, and green tea (Das et al. 2019). Bussa is a local millet drink consumed by people in Kenya. The finger millet is first germinated and allowed to ferment, and finally it is added to mixture of water and flour of maize or sorghum (Mburu 1986). Maheu is porridge with thin consistency made from finger millet and is used as a refresher drink in Zimbabwe. Finger millet flour is mixed with water to form a thin batter and then a small quantity of fermented flour is added as starter. The mixture is kept in warm place for a day. The fermented mixture is then added to boiling water with constant stirring to obtain a smooth thin porridge (Muza 1986). Pombe is an alcoholic beverage prepared from germinated finger millet. It is served during ritual ceremonies and labour work (Kubo 2016). Borde is a cereal-based traditional beverage in which finger millet is one of the essential ingredients. It is a low-alcohol beverage produced by spontaneous fermentation. It is of thick consistency with sweet-sour taste consumed by both adults and children. Basically, it is a low-cost meal replacement for poor people (Abegaz et al. 2002).

5.3

Small-Millet-Based Unconventional Food Products

Today with the increase in population and decline in resources, there arises need to provide alternative and novel food products with nutritional attributes. These food products should be readily available, accessible, and affordable for the general

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masses. The alternative food resources should be compliant with food and nutritional security. With the increase in knowledge and awareness about the hidden nutritional potential of small millets, researchers are working in the arena of development of nutritious food products based on small millets. Various small-millet-based food products have been developed and standardized. This chapter discusses the various novel, value-added, and modified ethnic small-millet-based food products and beverages.

5.3.1

Ready-to-Eat and Ready-to-Cook Mixes

In present time, with transition in lifestyle, lack of time, and customary culinary skills, ready-to-eat (RTE) and ready-to-cook (RTC) mixes have come up with the best alternative to enjoy the desired food. Researches have shown that small millets have the potential of being entering into the market of convenience food. Certain small-millet-based RTC and RTE mixes have been developed. For instance, Aigal (2014) developed foxtail millet flakes. Foxtail millets (FoM) were tempered, steamed, cooled, and passed in the roller to obtain flakes. These flakes were sundried to obtain ready-to-cook foxtail millet flakes. The flakes were further incorporated in traditional dishes to prepare avalakki and carrot millet kheer mix. Both the recipes were acceptable with a score of 7.5 and 7.3 for avalakki and carrot millet kheer, respectively. Besides, paddu, dosa, fish fry, cutlet, pakoras, sponge cake, and egg patties were also prepared with ready-to-cook foxtail millet flakes. Instant dhokla mix was developed by Ransumithila and Saravana kumar (2019) in which foxtail millet was incorporated at 20% to Bengal gram flour. Dhokla is a fermented steamed snack food item. Ready-to-eat snack based on barnyard millet (BM) in which BM/potato mash/ tapioca powder used in 60:37:3 ratios was steam cooked and cold extruded with HTST (High Temperature Short Time) puffing technique. Microwave puffing technique was used to develop BM and potato-based oil-free ready-to-eat fast food (Kumar et al. 2018). Similarly RTE snack based on finger millet (FM) was developed by Sawant et al. (2013), where FM, maize, rice, and soyabean in 20:50:20:10 ratio were used as most suitable composite flour, extruded in co-rotating twin screw extruder and dried to 6–7% moisture. Finally the dried sample was mixed with spices and oil to prepare RTE snack. Judicious combination of other ingredients with foxtail millet at 60% (Deshpande and Poshadri 2011), finger millet and foxtail millet at 12.5% each (Rao et al. 2018), little millet (LM) at 10% (Saini and Yadav, 2018), and kodo millet (KM) at 52% (Sharmila and Athmasehi 2017) were used to prepare RTE snack using extrusion technique. Ready-to-eat mixtures were made by puffing millets and adding spices to them (Verma and Patel 2013). RTE mixes were developed for adai, pulav, and chapatti. For adai mix, 100 g each of BM, FoM, sorghum, and LM, 150 g each of green gram and Bengal gram dal, and 130 g of rice were added. For pulav mix, four millets 200 g each were added along with dehydrated vegetables. For chappati mix, four small millets 125 g each

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and 500 g of wheat flour were added. To these mixes, tray-dried cucumber and potato peel were added at 5%, 10%, and 15% level, and it was found that RTE mix at 5% was most suitable for adai and pulav, whereas for chappati 10% variation was more suitable as per overall acceptability (Balasasirekha and Santhoshini 2016).

5.3.2

Snacks

Korramurukulu is a crispy savoury Indian snack made from FoM and Bengal gram flour to which spices were added and stiff dough was prepared. The dough was extruded to make murukus which are deep-fried and served (Kumar et al. 2018). Pakora (fritters) are commonly eaten snack. To FM, flour garlic, spices, salt, and onion rings were added. Water was added to make liquid paste and dropped in oil, deep-fried to make FM pakoras (Verma and Patel 2013). Finger millet chips were prepared using two techniques—frying and baking. The basic ingredients used were FM (20 g), rice flour (20 g), black gram dal flour (5 g), and spices. Water and ghee were added to make dough. Small balls of dough were taken and rolled into sheets to prepare chips (Vaishnavi and Sinthyia 2018). Chaat poories were made by incorporating FoM and LM at 40% and 60%, respectively, to wheat flour. It was found that small millets chat poories were at par with control wheat poories in terms of sensory attributes, viz. colour, shape, texture, and taste, as well as nutritional attributes like ash content, protein, and fibre (Shwetha et al. 2018). Sweet balls made from puffed kodo and kutki millet (LM) mixed with jaggery were found to be acceptable by the respondent groups comprising of teachers and students (Rajput et al. 2019).

5.3.3

Baked Products

Biscuits, cakes, and cookies made from small millets, viz. foxtail millet, finger millet, proso millet (PM), and barnyard millet, in combination with other ingredients like soybean flour, green gram flour, and wheat flour have been developed (Kumar et al. 2018). Finger-millet-based baked products like choco cup cake, gel cake, masala cake, carrot cake, rusk, and muffins were found to be quite acceptable in their texture and colour (Jaybhaye et al. 2014). Little millet composite flour breads were prepared using different processing techniques of washing, soaking, steaming, popping, and roasting of little millet. The composite flour was prepared by adding LM flour at 30% level to refined wheat flour. The overall sensory acceptability score ranged from 6.62 to 7.46 (Deshmukh and Yenagi 2016). Soy-kodo millet and soy-little millet biscuits were developed by Kumar et al. (2010). They found that on replacing wheat flour with 70% of KM and 90% of LM flour, soy millet biscuits were most acceptable.

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Multi small millets flour blend was used to develop cookies. KM, LM, FoM, FM, and whole wheat flour at 20% each was used to develop cookies which were found to be highly acceptable with hypoglycaemic properties (Subbulakshmi and Malathi 2017). Cake was made by incorporating FM flour to wheat flour, and it was seen that adding FM flour up to 50% did not affect the sensory score of cake and the millet cake was superior in calcium, iron, and phosphorus content compared to control wheat flour cake (Desai et al. 2010). Muffins were prepared using FM malt. The FM malt was added at 20% 30%, 50%, 90%, and 100% level, and it was found that muffins with 90% FM malt was most acceptable and better than their control in terms of sensory, textural, and nutritional parameters (Prakash and Chopra 2016). BM bran after suitable treatment was incorporated in rusks and muffins, and it was seen that rusk at 85:15 blend and muffins at 75:25 were highly acceptable and superior in nutrients (Nazni and Karuna 2016). An attempt to develop cookies, biscuit, and cake from foxtail millet by replacing wheat flour at 10%, 20%, 30% was done by Shadang and Jaganathan (2014).

5.3.4

Extruded Products

Noodles-vermicelli was prepared through cold extrusion process. Various combinations of FM with wheat flour and soy flour were used to prepare the vermicelli (Verma and Patel 2013). Five types of vermicelli and pasta were made from KM, BM, FoM, LM, and PM. Each small millet mix was in ratio of 50:40:10 for millet flour/wheat flour/soy flour. Vermicelli kheer and masala pasta were prepared from each of the mix, and it was found that FoM and KM scored highest, and in the case of masala pasta, LM and PM scored the same as control. All the small millet mixes were higher in terms of nutrients, viz. protein, energy, fibre, calcium, iron, and phosphorus (Ranganna et al. 2014). Noodles, macaroni, and spaghetti were prepared by using various combinations of durum wheat, oat flour, malted FM flour, and soy flour, and it was observed that incorporation of all the ingredients till 5% was at par with control, in terms of cooking and sensory characteristics (Samta and Jood 2018). Attempts were made to develop vermicelli from malted FM flour (Lande et al. 2017) and noodles from malted FM flour (Kulkarni et al. 2012) and malted KM flour (Himabindu and Devanna 2015) at 30%. The noodles developed were at par with control in sensory and nutritional qualities. Namkeen sev and seviyan were prepared from millet composite flour. FoM flour, chickpea flour, and wheat flour in 40:30:30 ratio were used for composite flour after malting. It was revealed that incorporation of 50% composite flour was mixed with 50% Bengal gram flour for preparing namkeen sev and 50% refined wheat flour to prepare seviyan. Both the extruded products were acceptable (Gautam et al. 2014).

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Suri et al. (2020) prepared a ready-to-eat extruded snack rich in iron, protein, and vitamin C using barnyard millet, defatted soy protein, and gooseberry. Finger millet was also explored by Seth and Rajamanickam (2012) to prepare extruded snack. The maximum acceptability of the snack was obtained by incorporating 42.03% finger millet flour, 30% rice flour, 14.95% sorghum flour, and 12.97% soy flour.

5.3.5

Fermented Products

Paddu, a fermented breakfast food item commonly eaten in Southern India, was prepared using LM instead of commonly used rice. LM and other ingredients were used in 6:1 ratio (little millet 81.48, black gram dhal 13.58, Bengal gram dhal 1.36, red gram dhal 1.36, fenugreek seed 0.82, and flaked rice 1.4 g). Little millet and pulses were soaked and ground to paste, followed by fermentation and finally shallow fried to prepare paddu (Madalageri et al. 2016). Nere happala is basically rice papad. Attempts were made to develop papad from FM, FoM, and LM. The millets were soaked for 7 days and ground to paste, followed by allowing fermentation for 12 h. The batter was then spread in an oil-smeared circular plate and steamed to prepare the papad. These raw papad were finally deep-fried before serving (Kamat and Yenagi 2012). Dosa mixes were prepared by incorporating LM and lentil in the control mix. Dosa mix prepared with LM, rice, black gram, and lentil in 40:30:20:10 ratio has similar sensory acceptability and is superior in nutritional attributes as compared to control dosa mix, i.e. rice:black gram in 70:30 ratio (Roopa et al. 2017). Germinated millet mix was obtained by mixing FM, KM, FoM, LM, and PM in equal proportion. A 50% of this mix was added to rice flour to make dosa mix, and it was seen that the millet dosa was liked extremely and was superior in nutritional composition as compared to control rice dosa (Krishnamoorthy et al. 2013). Idli, a type of fermented rice cake, was made by replacing parboiled rice with 50% of BM. The rest of the ingredients, viz. black gram dhal and fenugreek seeds, were the same for control rice idli and BM idli. All the ingredients were soaked overnight and ground to paste. The paste was allowed to ferment for 8 h. Finally, the batter was poured in the moulds for steaming and idlis were prepared. The BM idli was found to be acceptable with superior nutritional parameters compared to control (Vanithasri and Kanchana 2013). Similarly, LM was explored to make idlis, and it was found that LM and black gram in 4:1 ratio fermented for 12 hours produced most acceptable idlis (Balasubramaniun et al. 2015). The millet mix used for dosa mix by Krishnamoorthy et al. (2013) was also used to prepare idli and was found to be acceptable and better in nutritional parameters than its counterpart.

5.3.6

Baby Food/Complementary Food

Malting technique was adopted by Murthy et al. (2016) to prepare complementary food. Malted FoM at 30 parts, wheat at 40 parts enriched with whey protein

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concentrate at 2% and skim milk powder with 12% sugar, and ghee at 7 parts were used to formulate the complementary food. The developed food matched with the legal standards prescribed by FSSAI and can be effectively utilize to overcome nutritional deficiencies. A complementary porridge was prepared using composite flour composed of malted FM flour and precooked cowpea flour. The complementary food showed an increase in nutrients and a decrease in anti-nutrients with positive sensory properties due to malting of finger millet (Syeunda et al. 2019).

5.3.7

Beverages

Finger millet soup was prepared using FM and water mix (1:2.5). The mix was boiled for 15–17 min under medium heat till cooked. Curd and salt were added to the soup mix and served hot (Verma and Patel 2013). Little millet soup was prepared by adding 40 g of RTC soup mix to 300 ml of boiled water. The soup mix was prepared by adding parboiled LM at 60%, 70%, and 80%. It was seen that all the variations compared well with the standard. The variation with 80% LM was most acceptable and had good textural and nutritional quality (Karuna and Nazni 2018). Health drink was prepared from malted small millet composite flour. FM, KM, LM, and BM in 50:20:20:10 ratio were used to prepare the highly acceptable mix. The composite flour at 100 g was added to 1000 ml of water or milk to prepare the health drink (Nishad et al. 2017). Parvathi et al. (2015) prepared a nutrient-rich health drink with high consumer acceptability. Whole wheat flour, malted pearl millet flour, roasted kodo millet flour, malted green gram flour, roasted Bengal gram flour, jaggery, and skim milk powder in 30:10:10:15:10:20:5 ratio were used to prepare the mix. The mix at 20 g was added to 200 ml of boiled milk to prepare the health drink. Similar attempt was made by Rajput et al. (2019) to develop drink from malted kodo and kutki millet, which was found to be acceptable by the consumers (teachers and students). Srivastava and associates have also developed few novel and modified traditional food products based on small millets. Tables 5.1, 5.2, and 5.3 shows the list of smallmillet-based standardized products. Various commonly eaten food products were also modified using small millets by Srivastava et al. (2001b). These food products were specifically designed according to the increased nutritional needs of growing children and pregnant and lactating mothers. This segment of population is particularly nutritionally vulnerable in developing country like India, and therefore multipurpose mixes were developed using finger millet flour, barnyard millet flour, proso millet flour, and foxtail millet flour after malting and popping in combination with roasted soybean flour (black variety) or peanut flour or malted wheat flour. Various nutritious food products were formulated from these mixes, viz. sweet gruel (FM malt, whole wheat malt, and roasted soybean flour), sweet biscuits (PM malt, roasted soybean, and peanut flour), burfi-sweet meat (FM malt, wheat malt, roasted soybean flour, and skim milk

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Table 5.1 Developed weaning food and mixes recipe/dish along with their ingredients/method and acceptability scores

S. No. 1.a.

Dish/ recipe Weaning mix

1.b.

Weaning gruel

2.a.

Weaning mix

2.b.

Weaning gruel

2.c.

Weaning ladoo

3.a.

Weaning mix

3.b.

Weaning gruel

Ingredients/method of preparation Parboiled rice:Green gram flour: Soyabean flour::8:1:1 (base mix) Base mix:Malted finger millet flour::50: 50 25 g of above weaning mix +70 ml lukewarm water +10 g sugar Wheat flour:Roasted/malted finger millet flour:Green gram flour: Skimmed milk::30:30:25:15 25 g of malted light variety finger millet mix +60 ml. Of lukewarm water +10 g sugar 25 g of malted dark variety finger millet mix +60 ml. Of lukewarm water +10 g sugar 25 g of roasted light variety finger millet mix +60 ml. Of lukewarm water +10 g sugar 25 g of roasted dark variety finger millet mix +60 ml. Of lukewarm water +10 g sugar Weaning mix (malted light variety of finger millet) was roasted in ghee and sugar was added to make round balls Weaning mix (malted dark finger millet variety) was roasted in ghee and sugar was added to make round balls Weaning mix (roasted light finger millet variety) was roasted in ghee and sugar was added to make round balls Weaning mix (roasted dark variety) was roasted in ghee and sugar was added to make round balls Malted foxtail millet flour:Malted barnyard millet flour:Roasted soybean flour:Skim milk powder::30:30:25:15 25 g of above mix +60 ml lukewarm water +10 g sugar

Overall acceptability score –

7.6

–

7.43 8.16 7.73 8.3

References Limbu and Srivastava (2013) Limbu and Srivastava (2013) Shukla and Srivastava (2011) Shukla and Srivastava (2011)

9.38 9.36 8.56 8.95

Shukla and Srivastava (2011)

–

Thathola and Srivastava (2002) Thathola and Srivastava (2002)

7.7

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Table 5.2 Standardization of various small-millet-based mixes with their ingredients and acceptability score

Ingredients/recipe Finger millet flour:Soyabean flour: Malted fenugreek flour:Popped amaranth seeds::65:10:20:5 Barnyard millet flour:Soyabean flour: Malted fenugreek flour:Popped amaranth seeds::65:10:20:5 Finger millet:Fenugreek:Roasted Bengal gram::60:20:20

Overall acceptability score Acceptable

S. No 1.a.

Mix Laddu mix

1.b.

Laddu mix

2.a.

Batti mix

2.b.

Batti mix

Barnyard millet:Fenugreek:Roasted Bengal gram::60:20:20

Acceptable

3.a.

Khichadi mix

Finger millet:Fenugreek:Whole green gram::60:20:20

Acceptable

3.b.

Khichadi mix

Finger millet:Fenugreek:Whole green gram::60:20:20

Acceptable

4.a.

Convenience mix

4.b.

Sweet gruel

Malted proso millet:Roasted soybean flour:Roasted groundnut flour::70: 15:15 Popped proso millet:Roasted soybean flour:Roasted groundnut flour::70: 15:15 50 g malted convenience mix +60 ml lukewarm water +10 g sugar

4.c.

Salty gruel

50 g malted convenience mix + cooked vegetables + salt to taste

6.9

4.d.

Halwa

7.2

4.e.

Burfi

4.f.

Biscuits

5.

Biscuit mix

6.

Cheela mix

50 g malted convenience mix + boil water +20 g sugar + cardamom powder 50 g malted convenience mix +20 g sugar syrup (set in greased plate and garnished with amaranth seeds and coconut scrapings) 50 g malted convenience mix +25 g sugar +5 g fat + baking powder (baked for 30 min) 50 g malted finger millet flour +40 g wheat flour refined +10 g roasted black soyabean powder +3 g spinach powder 60 g malted finger millet flour +30 g roasted black soyabean +10 g malted wheat flour +3 g spinach powder

Acceptable

Acceptable

7.7

6.8

6.6

8.4

7.9

References Arora and Srivastava (2002) Arora and Srivastava (2002) Arora and Srivastava (2002) Arora and Srivastava (2002) Arora and Srivastava (2002) Arora and Srivastava (2002) Srivastava et al. (2001a)

Srivastava et al. (2001a) Srivastava et al. (2001a) Srivastava et al. (2001a) Srivastava et al. (2001a) Srivastava et al. (2001a) Srivastava and Singh (2003) Srivastava and Singh (2003) (continued)

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Table 5.2 (continued) Overall acceptability score 8.0

S. No 7.a.

Mix Kachari mix

7.b.

Kachari mix

Ingredients/recipe 60 g malted finger millet flour +10 g roasted black soyabean flour +3 g spinach powder Barnyard millet flour:Rice flour::55:45

7.c.

Kachari mix

Foxtail millet flour 100%

Liked very much >7

8.

Kachori mix

8.1

9.

Laddu mix

10.

Mathri mix

11.

Sattu/halwa mix

12.

Sevain mix

13.

Dhokla mix

14.

Uppma mix

15.

Laddu mix

60 g malted finger millet flour +20 g roasted black soyabean flour +20 g malted wheat flour +3 g spinach powder 50 g popped millet flour +40 g popped amaranth seeds +10 g roasted black soyabean flour 60 g malted finger millet flour +10 g malted wheat flour +10 g lentil flour +3 g spinach powder 60 g roasted millet flour +30 g roasted gram powder +10 g roasted groundnut powder 60 g malted finger millet flour +10 g roasted black soyabean flour +30 g refined wheat flour +3 g spinach powder Foxtail millet and barnyard millet flour:Legume flour:Fenugreek flour::55:35:10 Foxtail millet and barnyard millet flour:Legume flour:Fenugreek flour: Defatted coconut flour::60:20:10:10 Popped foxtail millet and amaranth seed flour:Legume flour:Fenugreek flour paste::50:25:25

Liked very much >7

7.8

8.0

7.1/8.2

7.5

Liked moderately Liked moderately Liked moderately

References Srivastava and Singh (2003) Srivastava and Singh (2003) Srivastava and Singh (2003) Srivastava and Singh (2003) Srivastava and Singh (2003) Srivastava and Singh (2003) Srivastava and Singh (2003) Srivastava and Singh (2003) Pathak et al. (2000) Pathak et al. (2000) Pathak et al. (2000)

powder), and halwa—a type of sweet pudding (FoM malt, BM malt, roasted soybean flour, and skim milk powder). These developed food products were found to be rich in energy and protein and most suitable for infants and young children. Fig. 5.1 shows food products developed from small millets. The malted FoM and BM were further explored to develop various products like panjiri, panjiri laddu (sweet ball), dhokla (fermented salted cake traditionally made from Bengal gram flour), samosa (fried pastry with savoury filling), bharva paratha (shallow fried flatbread with fillings), kachori (fried pastry with pulses as filling),

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Table 5.3 Development of various snacks and meal food items with their ingredients and acceptability scores S. No 1.a.

Snacks/ meal food item Biscuits

1.b.

Biscuits

1.c.

Biscuits

1.d.

Biscuits

1.e.

Biscuits

2.a.

Burfi

2.b.

Burfi

2.c.

Burfi

3.

Muffins

4.a.

Overall acceptability score Acceptable

Pulao

Ingredients/recipe Finger millet flour:Refined wheat flour::50:50 (other ingredients added were soy flour, sugar, fat, cocoa powder) Barnyard millet flour:Refined wheat flour::50:50 (other ingredients added were soy flour, sugar, fat, cocoa powder) Foxtail millet flour:Refined wheat flour::45:55 (other ingredients added were fat, powdered sugar, eggs, curd, baking powder) Barnyard millet flour:Refined wheat flour::45:55(other ingredients added were fat, powdered sugar, eggs, curd, baking powder) Finger millet flour:Soyabean flour:Mint leaf powder:Refined wheat flour::50: 20:10:20 Foxtail millet flour:Bengal gram flour::43:57 (other ingredients added were sugar, fat, powdered cardamom) Barnyard millet flour:Bengal gram flour::43:57 (other ingredients added were sugar, fat, powdered cardamom) Malted finger millet flour:Roasted groundnut flour::70:30 (other ingredient was sugar) Foxtail millet flour (125 g) + sugar (110 g) + milk (130 ml) + egg (1) + baking and cocoa powder Barnyard millet (100%)

8.4

4.b.

Pulao

Barnyard millet:Fenugreek seeds::80:20

8.3

5.a.

Idli

Barnyard millet:Black gram dal::75:25

7.85

5.b.

Idli

Barnyard milet:Black gram dhal: Fenugreek seeds::55:25:20

7.8

6.

Noodles

Foxtail millet:Semolina::40:60

7.9

Acceptable

7.6

References Singh and Srivastava (2006) Singh and Srivastava (2006) Anju and Sarita (2010)

6.7

Anju and Sarita (2010)

7.8

Singh and Srivastava (2007) Bisht and Srivastava (2013) Bisht and Srivastava (2013) Kumari and Srivastava (2000) Bisht and Srivastava (2018) Srivastava and Singh (2003) Srivastava and Singh (2003) Srivastava and Singh (2003) Srivastava and Singh (2003) Agrawal et al. (2005)

8.2

8.2

7.20

8.4

(continued)

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Table 5.3 (continued) S. No 7.a.

Snacks/ meal food item Buns

7.b.

Buns

8.a.

Bread

8.b.

Bread

9.

Cake rusk

10.

Laddu

11.

Halwa

12.

Biryani

13. a.

Cake

13. b.

Cake

14.

Papad

15.

Kachari

16.

Namak pare

17a.

Doughnuts

Ingredients/recipe Finger millet flour:Refined wheat flour::20:80 Finger millet flour:Refined wheat flour::40:60 Foxtail millet flour:Refined wheat flour::30:70 Foxtail millet flour:Refined wheat flour::40:60 Finger millet (VL-146):Refined wheat flour::30:70 Finger millet (PRM-601):Refined wheat flour::30:70 Foxtail millet:Refined wheat flour::30:70

Finger millet(VL-149):Refined wheat flour::25:75 Finger millet(VL-328):Refined wheat flour::25:75 Foxtail millet Barnyard millet Foxtail millet Barnyard millet Foxtail millet Barnyard millet Foxtail millet flour:Refined wheat flour::60:40 (with gluten and egg) Foxtail millet flour:Refined wheat flour::30:70 (without gluten and with egg) Finger millet flour:Wheat flour::60:40 (without gluten) 100% finger millet flour (with gluten) Barnyard millet:Rice::55:45 Foxtail millet:Rice::55:45 Barnyard millet:Rice::55:45 Foxtail millet:Rice::100:0 Finger millet (VL-204):Soyabean flour: Refined wheat flour:Mint leaf powder::50:20:20:10 Finger millet(PRM-601):Refined wheat flour::30:70

Overall acceptability score 7.3 7.62

References Tiwari and Srivatava (2017)

7.8 7.85

Tiwari and Srivatava (2017)

7.45 7.7

Chhavi and Sarita (2012)

7.8

Arya and Srivastava (2009) Bisht et al. (2016)

8.4 7.98

7.7 8.4 8.0 8.1 9.0 7.3 8.5 8.2

Verma et al. (2015) Verma et al. (2015) Verma et al. (2015) Kaur and Srivastava (2007)

7.5 7.1

Verma (2004)

8.0 8.3 7.9 8.2 7.54

Srivastava et al. (2005) Srivastava et al. (2005) Singh and Srivastava (2012) Joshi et al. (2016)

8.0

(continued)

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Table 5.3 (continued) S. No 17b.

18a.

Snacks/ meal food item Eggless doughnuts

18b

Glutenfree muffins Muffins

19.

Sev

20. a. 20. b. 21.

Pizza Pizza Instant vermicelli

Ingredients/recipe Finger millet:Refined wheat flour::60:40 Barnyard millet:Refined wheat flour::40:60 Foxtail millet:Refined wheat flour::50:50 Finger millet (PRM-15) 100%

Finger millet:Refined wheat flour: Fat::84:36:40 g Finger millet:Refined wheat flour:Fat replacer::84:36:40 g (fat replacer-papaya:Banana:Curd::20: 10:10 g) Foxtail millet flour:Bengal gram flour::30:70 Finger millet flour:Refined wheat flour::40:60 Barnyard millet flour:Refined wheat flour::40:60 100% foxtail millet (other ingredients added were sugar, gluten, guar gum, GMS, and water)

Overall acceptability score

8.07

8.25 8.0

Liked very much >7 7.9 8 7.8

References Joshi and Srivastava (2020) Bisht and Srivastava (2016) Singh (2019)

Srivastava and Singh (2003) Shrestha (2017) Shrestha (2017) Kharkwal et al. (2017)

pulav (fried rice), and badiyaan (nuggets made from pulses) for pregnant and lactating mothers. These products were good source of energy, protein, iron, and calcium. Besides, some other nutritious food products were developed which may be used as staple food items for breakfast or main meals: Bharva paratha (FM malt and wheat malt), pulav (BM malt with lentils and vegetables), poha (a type of flattened rice, popped BM), dosa (fermented pancake, FM malt), ghugni (sprouted FM and whole Bengal gram), vegetable dalia (a type of porridge, BM malt rice, Bengal gram dal, green gram dal, vegetables), and sprouted salad (FM sprouts, green gram, and Bengal gram sprouts).

5.4

Conclusion

Small millets—the treasure of nutrients—have been marginalized, but in certain parts of the world, especially Asian and African continent, they have been a major part of diet since centuries. Millets have been processed by various techniques like grinding, popping, puffing, malting, fermentation, and baking to prepare traditional food and beverages. However, there is a lack of documentation of traditional food products based on millets. The present chapter attempts to document the available literature on types and preparation techniques of traditional foods and beverages

112

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BISCUITS

BUNS

DOUGHNUTS

MUFFINS

CAKES

PIZZA

BREAD

NAMAKPARE

KACHARI

CAKE

PAPAD

KHEER

IDLI

Fig. 5.1 Food products developed from small millets

NOODLES

LADDU

HALWA

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based on small millets. Besides being a major ingredient of traditional food products, small millets have immense potential to be included in our daily food basket. With slight modifications, traditional food products can be redesigned with good sensory, nutritional, and technological features. Also, novel food products may be developed from small millets which have new avenues to enter into commercial food sector. The small-millet-based products not only have the possibilities to fight against food and nutritional security but also have the elements to be branded as functional food. Few millet-based food and beverages have already entered and made their place into commercial market. More progress in this arena is required.

References Abegaz K, Beyene F, Langsrud T, Narvhus JA (2002) Indigenous processing methods and raw material of borde, an Ethiopian traditional fermented beverage. J Food Technol Africa 7(2): 59–64 Agarwal P, Singh G, Srivastava S (2005) Effect of different levels of foxtail millet flour, gluten and glycerol mono stearate (GMS) on the sensory attributes of noodles. Beverage Food World 32(2): 42–44 Aigal SS (2014) Development and evaluation of ready to cook foxtail millet (Setaria italica L) flakes. M.Sc. thesis (Food Science and Nutrition), College of Rural Home Science, Dharwad Amadou I, Gbadamosi OS, Le G-W (2011) Millet-based traditional processed foods and beverages—a review. Cereal Foods World. https://doi.org/10.1094/CFW-56-3-0115 Anju T, Sarita S (2010) Suitability of foxtail millet (Setaria italica) and barnyard millet (Echinochloa frumentacea) in development of low glycemic index biscuits. Malays J Nutr 16(3):361–368 Arora S, Srivastava S (2002) Suitability of millet-based food products for diabetics. J Food Science Technol 39(4):423–426 Arya C, Srivastava S (2009) Nutrient composition and glycemic response of foxtail millet bread. Beverage Food World 36(9):32–35 Balasasirekha R, Santhoshini P (2016) Development of RTE millet mixes with dehydrated vegetable peel. Int J Curr Microbiol App Sci 5(11):24–37 Balasubramanian S, Jincy MG, Ramanathan M, Chandra P, Deshpande SD (2015) Studies on millet idli batter and its quality evaluation. Int Food Res J 22(1):139–142 Bisht AT, Srivastava S (2013) Efficacy of millets in the development of low glycemic index sweets for diabetics. Malays J Nutr 19(2):215–222 Bisht B, Shrestha R, Srivastava S (2016) Utilization of finger millet in formulation of cake rusk. Poster presented at technical compendium National Conference on hill agriculture in perspective, Directorate of Experiment Station, G.B. Pant University of Agriculture and Technology, Pantnagar, 26–28, February 2016 Bisht D, Srivastava S (2016) Development of finger millet muffins for celiac disease. Poster presented at technical compendium National Conference on hill agriculture in perspective, Directorate of Experiment Station, G.B. Pant University of Agriculture and Technology, Pantnagar, 26–28 February 2016 Bisht D, Srivastava S (2018) Optimization of ingredients for development of gluten free muffins for celiac disease patients using response surface methodology. In: Abstract of the 9th Conference of the Indian Science Congress Association (Haridwar Chapter) on ‘Future India: Science and Technology’, G.B. Pant University of Agriculture and Technology, Pantnagar, 13–14 October 2018 Chhavi S (2012) Evaluation of composite millet breads for sensory and nutritional qualities and glycemic response. Malays J Nutr 18(1):89–101

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Das S, Khound R, Santra M, Santra DK (2019) Beyond bird feed: Proso millet for human health and environment. Agri 9:64. https://doi.org/10.3390/agriculture9030064 Desai AD, Kulkarni SS, Sahoo AK, Ranveer RC, Dandge PB (2010) Effect of supplementation of malted ragi flour on the nutritional and sensorial quality characteristics of cake. Adv J Food Sci Technol 2(1):67–71 Deshmukh P, Yenagi N (2016) Nutritional and functional properties of processed little millet flours in the development of composite flour bread. Int J Food Nutr Sci 5(3):42–52 Deshpande HW, Poshadri A (2011) Physical and sensory characteristics of extruded snacks prepared from foxtail millet based composite flours. Int Food Res J 18:751–756 Esele JPE (1986) Processing and utilization of finger millet in Uganda. In small millets in global agriculture. In: Seetharam A, Riley KW, Harinarayana G (eds) Small millets in global agriculture, Proceedings of the first International small millets workshop. Oxford and IBH Publishing, New Delhi Gautam L, Chaturvedi N, Gupta A (2014) Development of micronutrients rich homemade extruded food products with the incorporation of processed foxtail millet, wheat and chickpea. Indian J Community Health 26(S2):288–293 Himabindu P, Devanna N (2015) Development of nutrient rich noodles by supplementation with malted kodo millet flour. Int J Advance Res Technol (IJOART) 4(12):7–16 Jaybhaye RV, Pardeshi IL, Vengaiah PC, Srivastav PP (2014) Processing and technology for millet based food products: a review. J Ready Eat Food 1(2):32–48 Joshi A, Srivastava S (2020) Development and standardization for preparation of eggless doughnut using millets (Ragi, barnyard and foxtail). In: Abstracts of the international virtual conference on role of basic and applied sciences in human well being, G.B. Pant University of Agriculture and Technology, Pantnagar, 23–24 November 2020 Joshi S, Arya C, Srivastava S (2016) Development of finger millet incorporated doughnuts. Poster presented at technical compendium national conference on hill agriculture in perspective, Directorate of Experiment Station, G.B. Pant University of Agriculture and Technology, Pantnagar, 26–28 February 2016 Kajuna STAR (2001) Millet: post harvest operations. FAO, Rome. www.suanet.ac.tz Kamat S, Yenagi N (2012) Evaluation of indigenous technology of preparation of papad with special reference to cereals and millets. Indian J Tradit Know 11(1):123–133 Karuna TD, Nazni P (2018) Formulation, texture and sensory characteristics of little millet based RTC (ready-to-cook) soup mix. Int J Food Sci Nutr 3(2):187–191 Kaur G, Srivastava S (2007) Effects of gluten on sensory quality and physical characteristics of foxtail millet based chocolate cake. Beverage Food World 34(9):65–67 Kharkwal V, Srivastava S, Sharma SK (2017) Development of foxtail millet instant vermicelli. Paper presented at 49th Annual National Conference of the Nutrition Society of India, Assam Agricultural University, Assam Krishnamoorthy S, Kunjithapatham S, Manickam L (2013) Traditional Indian breakfast (Idli and Dosa) with enhanced nutritional content using millets. Nutr Diet 70:241–246 Kubo R (2016) The reason for preferential use of finger millet (Eleusine coracana) in eastern African brewing. J Inst Brewing 122:175–180 Kulkarni SS, Desai AD, Ranveer RC, Sahoo AK (2012) Development of nutrient rich noodles by supplementation with malted ragi flour. Int Food Res J 19(1):309–313 Kumar KS, Dattamazumdar S, Renu R (2018) Development of millet based foods enriched with peanuts and pulses. Int J Curr Microbiol App Sci 7(4):2903–2914 Kumar S, Rekha SLK (2010) Evaluation of quality characteristics of soy based millet biscuits. Adv Appl Sci Res 1(3):187–196 Kumari S, Srivastava S (2000) Nutritive value of malted flours of finger millet genotypes and their use in the preparation of burfi. J Food Science Technol 37(4):419–422 Lande SB, Thorats S, Kulthe AA (2017) Production of nutrient rich vermicelli with malted finger millet (Ragi) flour. Int J Curr Microbiol App Sci 6(4):702–710

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Sawant AA, Thakor NJ, Swami SB, Divate AD (2013) Physical and sensory characteristics of ready-to-eat food prepared from finger millet based composite mixer by extrusion cooking. Agric Eng Int: CIGR J 15(1):100–105 Scott A (2015) Why millet is staple food in parts of the world.www.academia.edu Seetharam A, Gowda KTK (n.d.) Production and utilization of small millets in India. www.acripsm. res.in Seth D, Rajamanickam G (2012) Development of extruded snacks usingsoy, sorghum, millet and rice blend-a response surface methodology approach. Int J Food Sci Technol 47:1526–1531 Shadang C, Jaganathan D (2014) Development and standardization of formulated baked products using millets. Int J Res Appl Nat Soc Sci 2(9):75–78 Sharmila B, Athmaselvi KA (2017) Development of ready to eat extruded snacks from blend of under-utilized legumes and millets. J Pharm Sci Res 9(6):947–954 Shrestha R (2017) Suitability of finger millet and barnyard millet incorporated pizza base in diabetes and cardiovascular diseases. PhD. Thesis (Human Nutrition), GB Pant University of Agriculture & Technology, Pantnagar Shukla K, Srivastava S (2011) Quality characteristics of finger millet based baby food preparation as affected by its varieties and processing techniques. Function Environ Bot 1(1):77–81 Shwetha K, Siddique A, Ramesh D, Prakash J, Prabhavathi SN (2018) Consumption pattern of Indian ‘chat’ based snacks and formulation of millet based snack Poories. Res J Food Nutr 2(4): 30–38 Singh P, Srivastava S (2006) Glycemic response of finger and barnyard millet biscuits. J Eco-friendly Agric 1(2):168–170 Singh P, Srivastava S (2007) Development of iron rich biscuit mixes using finger millet. J Commun Mobiliz Sustain Develop 2(1):89–94 Singh P, Srivastava S (2012) Formulation and quality evaluation of iron rich namak pare mixes using finger millet. Int J Life Sci 1(4):89–95 Singh R (2019) Development of finger millet muffins using fat replacers. MSc. (Foods and Nutrition) Thesis, GB Pant University of Agriculture and Technology, Pantnagar Srivastava A, Srivastava S, Dhyani M, Singh G (2005) Comparative study on nutritional quality of barnyard/foxtail millet kachari and traditional rice kachari. Beverage Food World 32:60–61 Srivastava S, Singh G (2003) Processing of millets for value addition and development of health foods. National Agriculture Technology Project (Rainfed Ecosystem) report. G.B. Pant University of Agriculture and Technology, Pantnagar Srivastava S, Thathola A, Batra A (2001a) Development and nutritional evaluation of proso milletbased convenience mix for infants and children. J Food Sci Technol 38(5):480–483 Srivastava S, Thathola A, Masud S, Mittal M (2001b) eksVs vuktksa ds ikSf”Vd o Lokfn”V O;atuA Department of Foods and Nutrition, GB Pant University of Agriculture & Technology, Pantnagar, Uttaranchal Subbulakshmi B, Malathi D (2017) Formulation of multi millet cookies and evaluate its hypoglycaemic effect in albino rats. J Crop Weed 13(3):112–116 Suri S, Dutta A, Shahi NC, Raghuvanshi RS, Singh A, Chopra CS (2020) Numerical optimization of process parameters of ready-to-eat (RTE) iron rich extruded snacks for anemic population. LWT-Food SciTechnol 134:1. https://doi.org/10.1016/j.lwt.2020/10164 Syeunda CO, Anyango JO, Faraj AK (2019) Effect of compositing precooked cowpea with improved malted finger millet on anti- nutrients content and sensory attributes of complementary porridge. Food Nutr Sci 10:1157–1178 Taylor JRN, Emmambux MN (n.d.) Traditional African cereal grains-overview Thathola A, Srivastava S (2002) Physicochemical properties and nutritional traits of millet based weaning food suitable for infants of Kumaon hills, northern India. Asia Pacific J Clin Nutr Australia 11(1):28–32 Tiwari N, Srivastava S (2017) Effect of finger millet (Eleusine Coracana) buns supplementation on serum glucose and serum lipids in type 2 diabetics. Asian J Dairy Food Res 36(4):337–340

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6

Small Millets Functional Foods Anju Bisht and Sarita Srivastava

Abstract

Today human race is suffering from host of diseases owing to behavioral changes and genetic predisposition. Health foods can play a crucial role in prevention and control of health disorders. Functional foods which are interchangeably termed as designer food, health food or nutraceuticals are in demand because of their efficacy in allaying the symptoms of ever-rising health disorders. Small millets which are natural, low-cost resource with tremendous nutritional and therapeutic properties can be explored as an ingredient in functional foods designed to manage diseased conditions like diabetes, cardiovascular disorders (CVDs), cancer, obesity, and celiac disease. The special attributes such as good content of dietary fiber, micronutrients, phytochemicals, and non-gluten-forming protein content present in small millets impart them with the therapeutic characteristics to be an apt ingredient in development of functional foods. Many human and animal researches have proved the efficiency of small millets as a functional food ingredient; however more studies in this arena are required. Keywords

Small millets · Functional food · Diabetes · CVD · Obesity · Cancer · Celiac disease

A. Bisht (*) Department of Home Science, MB Government PG College, Nainital, Uttarakhand, India S. Srivastava Department of Foods and Nutrition, College of Home Science, GB Pant University of Agriculture & Technology, Pantnagar, Uttarakhand, India # The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Srivastava (ed.), Small Millet Grains, Cereals, Pulses and Oilseeds, https://doi.org/10.1007/978-981-16-9306-9_6

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Introduction

Advancement in technology, industrialization, urbanization, influence of Western world, and fading of traditional lifestyle witnessed its negative aspect in the form of emergence of chronic degenerative diseases in India, since the mid-1990s. The rise in the degenerative diseases like diabetes, cardiovascular diseases (CVD), cancer, and obesity due to host of reasons like faulty eating habits, sedentary lifestyle, and inappropriate life modification factors call for the need of enlivening 2500-year-old tenet given by Hippocrates, the father of medicine – “Let food be thy medicine and medicine be thy food.” Nutrition science has also realized the importance of diet in prevention of diseases and maintenance of optimal health. Substantial researches in the past have shown the therapeutic function of food in controlling and preventing diseases. For example, the classic Mediterranean diet has been associated with the prevention of chronic diseases like CVD, obesity, and hyperlipidemia due to the presence of antioxidants, anti-inflammatory agents, and bioactive components like polyphenols, flavonoids, and phytosterols (Meryem and Havva 2017). With the recognition of importance of food in the prevention of diseases and maintenance of health came the concept of “functional food.” The term functional food was first coined in Japan in 1984, referring to food ingredients providing health benefits. Functional foods have three functions – providing nutrition, sensory satisfaction, and physiological function – and these foods are regulated under “Food for Specified Health Use” (FOSHU) in Japan (Shimizu 2003). Since then, the concept of functional food has travelled across the world. Although there has been no legal definition for functional foods, various organizations have proposed the definition for functional food as “any modified food or food ingredients that may provide health benefit beyond the traditional nutrient it contains” by the National Academy of Sciences or “foods that, by virtue of the presence of physiologically-active components, provide a health benefit beyond basic nutrition” by the International Life Sciences Institute or as “whole foods and fortified, enriched, or enhanced foods, have a potentially beneficial effect on health when consumed as part of a varied diet on a regular basis, at effective levels” by the American Dietetic Association (Hasler 2002). Almost at the same time, a new term “nutraceutical” cropped in the field of nutrition science. The term was coined by Dr. De Felice in 1989 which meant “food, or parts of a food, that provide medical or health benefits including the prevention and treatment of disease” (Kalra 2003). The term functional foods and nutraceuticals are often interchangeably used, but according to Torabally and Rahmanpoor (2019), nutraceutical is a broad term and functional food is one of the categories under nutraceuticals. The main function of nutraceuticals is to provide health benefits, prevent disease, and promote health and quality of life. Kalra (2003) redefined the association between the two terms: nutraceutical is when functional food helps in prevention and/or treatment of a disease or disorder other than anemia. Nutraceutical may be used as a conventional food or as the sole item of meal or diet. In 2014 at 17th International Conference jointly organized by USDA and ARS, Functional

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Food Center revised the definition of functional food as “Natural or processed food that contains known or unknown biologically-active compounds; which, in defined, effective non-toxic amounts, provide a clinically proven and documented health benefit for the prevention, management, or treatment of chronic disease” (Martirosyan and Singh 2015), specifying more precision to the term. However, there is still a need to bring clarity in defining functional food and nutraceuticals and understanding the nuances attached with these terms, but functional foods or nutraceuticals may be understood as food or part of food which owing to their specific bioactive components may help in preventing and/or treating diseases and promoting health after scientific testimony. Small millets are one such food crop which can act as functional food and help in the prevention and treatment of chronic degenerative diseases. Besides being nutritious and climate resilient, these crops have added advantage of being low cost thus reducing the burden of diseases. This chapter discusses the role of small millets as functional food in treating and preventing the chronic degenerative diseases like diabetes, CVD, cancer, obesity, and celiac disease along with the underlying mechanism/rationale.

6.2

Pathogenesis of Metabolic Disorders

There is an interrelationship among all the disorders like obesity, diabetes, CVD, and cancer and they are resultant of genetic and environment (nutrition) factors. Imbalance of nutrients (over-nutrition) coupled with poor physical activity leads to accumulation of visceral fat (obesity). Insulin resistance is caused by visceral fat, which is caused by several factors including generation of reactive oxygen species, induction of inflammation, production of cytokines, and an increased metabolic stress (Houstis et al. 2006; Hardy et al. 2012; Munoz et al. 2013). Insulin resistance may lead to abdominal obesity, hyperglycemia, elevated blood pressure, and dyslipidemia due to increased production of free fatty acids, increased level of very-low-density lipoprotein, decreased uptake of glucose, increased gluconeogenesis, and impaired vasodilation (Gallagher et al. 2010). Insulin resistance becomes a risk factor for noncommunicable diseases like diabetes, CVD and cancer which are seen to be interrelated. It has been observed that people with coronary heart diseases and impaired fasting blood glucose are at risk of developing type 2 diabetes and vice versa. Diabetes mellitus is related to the risk of cancer like liver, pancreatic, colorectal, and breast cancer and leukemia. Cancer patients are prone to cardiotoxicity. On the other hand, CVDs in cancer patients may be an outcome of chemotherapy and hypertension as a risk factor for renal cell carcinoma. Other risk factors like smoking, diet, physical inactivity, and psychological factors further exaggerate the association between these disorders (Hu et al. 2014). Dietary interventions can play a vital role in control of the metabolic syndrome. Dietary components like PUFA, MUFA, branched-chain amino acids, polyphenols, and micronutrients can help in improving insulin sensitivity. Incorporation of

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functional foods/nutraceuticals in diet can promote the alleviation of associated symptoms (Xu et al. 2019; Rochlani et al. 2017).

6.3

Nutritional Approach to Treat and/or Prevent Chronic Degenerative Diseases

Diet has always been recognized as an effective tool in managing diseases. For instance, the first attempt to modify diabetes mellitus by diet was made by the Egyptians in 3500 B.C. In India as far back as 2500 years ago, Sushruta and Charaka realized the importance of dietary restriction in the treatment of diabetes mellitus. They adopted measures to correct obesity in diabetics by prohibiting the use of sugar, jaggery, wines, ghee, butter, and meat. In the twentieth century, prior to the discovery of insulin, the treatment of diabetes included intermittent fasting, under nutrition, and carbohydrate restriction (Joslin 1949). Sooner it was realized that all types of carbohydrates do not produce similar effect in body, and thus the concept of glycemic index (GI) was introduced by Jenkins et al. (1981). GI is defined as the ratio of area under the blood glucose response curve after consumption of 50 g carbohydrate from a test food and the area under the curve after consumption of 50 g carbohydrate from a control food. The control food may be either white bread or glucose. Foods with higher GI raise blood sugar more rapidly compared to foods with lower GI. On the basis of GI values, foods are categorized as low glycemic index foods (GI ¼ 55), moderate glycemic index foods (GI ¼ 56–69), and high glycemic index foods (GI ¼ 70 or more) (Brand-Miller et al. 1999). Low GI foods have proven their significant role in treatment and control of various metabolic disorders like diabetes, CVD, obesity, and cancer. Researches have inferred that low GI foods decrease insulin resistance, beta cell dysfunction, hyperinsulinemia, free fatty acids, inflammation, endothelial dysfunction, and prothrombotic factors, thereby reducing glycemia, dyslipidemia, hypertension, and hence risk factors for CVDs, diabetes, obesity, and cancer. Low GI foods also increase satiety and decrease hunger thereby influencing nutritional status of an individual (Aston 2006; Radulian et al. 2009). Food products based on small millets have been seen to be very suitable in development of low and medium GI food products. It has been observed that incorporation of small millets to traditional food products make them more suitable as low GI food products compared to their traditional counterparts. Table 6.1 and Fig. 6.1 show the small-millet-based low GI food products.

6.4

Small Millets and Chronic Degenerative Diseases

Small millets are said to be powerhouse of nutrients. They are good source of protective nutrients, essential fatty acids, essential amino acids, and fiber. They are also rich source of functional ingredients like polyphenols, lignans, beta glucan,

33.95

34.62

36.12

36.2

36.57

36.8

38

Biscuits

Laddu

Batti

Pizza base

Buns

Cheela

Porridge (parboiled for 30 min. and roasted)

Arora and Srivastava (2002) Arora and Srivastava (2002) Shrestha (2017) Tiwari and Srivastava (2017) Kumari et al. (2014) Kumari et al. (2020) Batti

Pizza base

Khichdi

Pulav a. Fresh b. Instant Rehydrated cooked Laddu

36.71

36.6

34.96

34.6

34.26 34.12

GI value 27.24

Arora and Srivastava (2002)

Shrestha (2017)

Arora and Srivastava (2002) Joshi and Srivastava (2016)

References Arora and Srivastava (2002) Joshi (2016)

Biscuit

Bread

Cookie bar

Foxtail millet Burfi

50.8

49.53

37.6

GI value 37.5

Chhavi and Sarita (2012) Anju and Sarita (2010)

References Bisht and Srivastava (2013) Lestari et al. (2017)

Little millet RTC flakes

GI value 52.11

(continued)

References Patil et al. (2015)

Barnyard millet Khichadi

References Arora and Srivastava (2002) Hymavathi et al. (2017)

Table 6.1 Low GI food products made from small millets

GI value 25.33

Small Millets Functional Foods

Finger millet Khichadi

6 123

GI value 38.7

41.43

43.10

45 (large particle size) 48 (small particle size)