Fats and Oils Formulating and Processing for Applications - Formulating and Processing [3rd ed] 1-4200-6166-6, 978-1-4200-6166-6

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Third Edition

Fats Oils and

Formulating and Processing for Applications

Third Edition

Fats Oils and

Formulating and Processing for Applications Richard D. O’Brien

CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2009 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed in the United States of America on acid-free paper 10 9 8 7 6 5 4 3 2 1 International Standard Book Number-13: 978-1-4200-6166-6 (Hardcover) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging-in-Publication Data O’Brien, Richard D. Fat and oils : formulating and processing for applications / Richard D. O’Brien. -- 3rd ed. p. cm. Includes bibliographical references and index. ISBN-13: 978-1-4200-6166-6 ISBN-10: 1-4200-6166-6 1. Oils and fats, Edible. I. Title. TP670.O27 2009 664’.3--dc22 Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com

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Contents Third Edition Preface..............................................................................................xix Chapter 1 Raw Materials ............................................................................................................1 1.1 1.2 1.3 1.4 1.5 1.6 1.7

1.8 1.9

1.10

1.11

1.12

1.13 1.14 1.15

1.16

Introduction .....................................................................................................1 Sources of Fats and Oils..................................................................................2 Vegetable Oil Yields .......................................................................................2 Availability of Fats and Oils ...........................................................................4 United States Utilization of Edible Fats and Oils ...........................................4 Characterization of Fats and Oils ...................................................................7 Nonglyceride Components of Fats and Oils....................................................8 1.7.1 Phospholipids .....................................................................................8 1.7.2 Tocopherols and Tocotrienols ............................................................9 1.7.3 Sequalene ......................................................................................... 10 1.7.4 Sterols .............................................................................................. 10 1.7.5 Pigments........................................................................................... 12 1.7.6 Pesticides.......................................................................................... 13 1.7.7 Trace Metals..................................................................................... 13 Genetically Modiied Vegetable Oils ............................................................ 13 Soybean Oil ................................................................................................... 15 1.9.1 Soybean Oil Composition and Physical Properties ......................... 17 1.9.2 Genetically Modiied Soybean Oil .................................................. 18 Cottonseed Oil .............................................................................................. 19 1.10.1 Cottonseed Oil Composition and Physical Properties .....................20 1.10.2 Genetically Modiied Cottonseed Oil .............................................. 22 Peanut Oil ...................................................................................................... 22 1.11.1 Peanut Oil Composition and Physical Properties ............................ 23 1.11.2 Genetically Modiied Peanut Oil .....................................................25 Corn Oil ........................................................................................................25 1.12.1 Corn Oil Composition and Physical Properties ...............................26 1.12.2 Genetically Modiied Corn Oil ........................................................28 Sunlower Oil ................................................................................................28 1.13.1 Sunlower Oil Composition and Physical Properties ....................... 29 NuSun Sunlower Oil .................................................................................... 30 1.14.1 NuSun Composition and Physical Properties .................................. 31 High-Oleic Sunlower Oil ............................................................................. 32 1.15.1 High-Oleic Sunlower Oil Physical Properties and Composition .............................................................................. 32 Saflower Oil ................................................................................................. 33 1.16.1 Saflower Oil Composition and Physical Properties ........................ 33

v

vi

Contents

1.17

High-Oleic Saflower Oil .............................................................................. 35 1.17.1 High-Oleic Saflower Oil Composition and Physical Characteristics ................................................................................. 35 1.18 Canola Oil ..................................................................................................... 37 1.18.1 Canola Oil Composition and Physical Properties ............................ 37 1.18.2 Genetically Modiied Canola Oil ..................................................... 39 1.19 Olive Oil ........................................................................................................40 1.19.1 Olive Oil Composition and Physical Properties .............................. 41 1.20 Palm Oil ........................................................................................................ 43 1.20.1 Palm Oil Composition and Physical Properties ............................... 43 1.20.2 Genetically Modiied Palm Oil ........................................................ 47 1.21 Coconut Oil ................................................................................................... 48 1.21.1 Coconut Oil Composition and Physical Properties.......................... 48 1.22 Palm Kernel Oil ............................................................................................ 50 1.22.1 Palm Kernel Oil Composition and Physical Properties ................... 51 1.23 Lard ............................................................................................................... 52 1.23.1 Lard Physical Properties and Composition...................................... 53 1.24 Tallow ............................................................................................................ 55 1.24.1 Tallow Physical Properties and Composition .................................. 56 1.25 Milk Fat ......................................................................................................... 58 1.25.1 Milk Fat Physical Properties and Composition ............................... 58 1.26 Menhaden Oil................................................................................................60 1.27 Single Cell Oils .............................................................................................64 1.27.1 Microalgae Oils ...............................................................................64 1.27.2 Fungal Oil ........................................................................................ 65 References ...........................................................................................................66 Chapter 2 Fats and Oils Processing .......................................................................................... 73 2.1 2.2

2.3 2.4

Introduction ................................................................................................... 73 Fats and Oils Recovery ................................................................................. 74 2.2.1 Oilseed Extraction ........................................................................... 74 2.2.1.1 Expeller or Screw Press Extraction .................................. 76 2.2.1.2 Prepress Solvent Extraction.............................................. 77 2.2.1.3 Direct Solvent Extraction ................................................. 77 2.2.2 Oil-Bearing Fruit Extraction............................................................ 78 2.2.2.1 Olive Oil Extraction ......................................................... 78 2.2.2.2 Palm Oil Extraction.......................................................... 78 2.2.3 Animal Fat Recovery ....................................................................... 79 2.2.3.1 Wet Rendering .................................................................. 79 2.2.3.2 Dry Rendering .................................................................. 79 Reining Systems...........................................................................................80 Physical Reining ..........................................................................................80

Contents

2.5

2.6

2.7

2.8

vii

Reining Pretreatment ................................................................................... 83 2.5.1 Water Degumming...........................................................................84 2.5.2 Acid Degumming............................................................................. 85 2.5.3 Dry Degumming .............................................................................. 86 2.5.4 Enzymatic Degumming ................................................................... 86 2.5.5 Modiied Acid Degumming ............................................................. 87 2.5.6 Membrane Filter Degumming ......................................................... 87 Chemical Reining ........................................................................................ 88 2.6.1 Short-Mix Caustic Reining .............................................................92 2.6.2 Miscella Reining .............................................................................92 2.6.3 Batch Caustic Reining .................................................................... 95 2.6.3.1 Dry-Method Batch Reining ............................................. 95 2.6.3.2 Wet-Method Batch Reining .............................................96 2.6.4 Silica Reining..................................................................................96 2.6.5 Reining Eficiency ..........................................................................97 2.6.6 Reining Byproducts ........................................................................ 98 2.6.6.1 Soapstock Processing ....................................................... 98 2.6.6.2 Hydrated Gums Processing ............................................ 100 Prebleaching ................................................................................................ 100 2.7.1 Procedure ....................................................................................... 101 2.7.1.1 Batch Atmospheric ......................................................... 101 2.7.1.2 Batch Vacuum ................................................................ 101 2.7.1.3 Continuous Vacuum ....................................................... 101 2.7.2 Bleaching Agents ........................................................................... 103 2.7.2.1 Natural Bleaching Earth................................................. 103 2.7.2.2 Activated Bleaching Earth ............................................. 103 2.7.2.3 Reuse Spent Bleaching Earth ......................................... 104 2.7.2.4 Activated Carbon............................................................ 104 2.7.2.5 Silica Adsorbent ............................................................. 105 2.7.3 Bleaching Earth Dosage ................................................................ 105 2.7.4 Temperature ................................................................................... 106 2.7.5 Time ............................................................................................... 107 2.7.6 Moisture ......................................................................................... 107 2.7.7 Filtration......................................................................................... 108 2.7.8 Bleaching Byproduct...................................................................... 109 Hydrogenation ............................................................................................. 110 2.8.1 Operating Variables ....................................................................... 113 2.8.1.1 Temperature.................................................................... 113 2.8.1.2 Pressure .......................................................................... 113 2.8.1.3 Agitation ......................................................................... 114 2.8.1.4 Catalyst Level ................................................................. 114 2.8.1.5 Catalyst Type .................................................................. 114 2.8.1.6 Catalyst Poisons.............................................................. 115

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2.9

2.10

2.11

2.12

2.13 2.14 2.15

2.16 2.17

Contents

2.8.1.7 Catalyst Reuse ................................................................ 116 2.8.1.8 Source Oils ..................................................................... 116 2.8.2 Hydrogenation Systems.................................................................. 116 2.8.3 Hydrogenation Control................................................................... 118 2.8.4 Hydrogenated Basestock System ................................................... 119 Interesteriication ........................................................................................ 122 2.9.1 Chemical Rearrangement Catalyst ................................................ 124 2.9.2 Endpoint Control ............................................................................ 126 2.9.2.1 Melting Point .................................................................. 126 2.9.2.2 Fiber Optic Spectrometer Monitoring ............................ 126 2.9.2.3 Solids Fat Index .............................................................. 127 2.9.2.4 Differential Scanning Calorimetry ................................ 127 2.9.2.5 Glyceride Compositional Analysis ................................. 128 2.9.3 Random Chemical Interesteriication Processes ........................... 128 2.9.4 Directed Chemical Interesteriication Process .............................. 130 2.9.5 Enzymatic Interesteriication ......................................................... 131 2.9.6 Interesteriied Fats and Oils Applications ..................................... 132 Winterization............................................................................................... 133 2.10.1 Classical Winterization Process..................................................... 133 2.10.2 Winterization Principle .................................................................. 134 2.10.2.1 Source Oil Composition ................................................. 135 2.10.2.2 Cooling Rate................................................................... 135 2.10.2.3 Crystallization Temperature ........................................... 135 2.10.2.4 Agitation Rate ................................................................ 135 2.10.2.5 Crystallization Time....................................................... 136 2.10.3 Solvent Winterization .................................................................... 136 2.10.4 Winterization Process Control Procedures .................................... 137 2.10.5 Winterization Applications ............................................................ 138 Dewaxing .................................................................................................... 139 2.11.1 Dewaxing Process Control ............................................................ 140 2.11.2 Dewaxing Applications .................................................................. 140 Fractionation ............................................................................................... 140 2.12.1 Dry Crystal Fractionation .............................................................. 142 2.12.2 Detergent Fractionation.................................................................. 142 2.12.3 Solvent Fractionation ..................................................................... 143 Postbleaching .............................................................................................. 144 Cholesterol Stripping Process ..................................................................... 145 Esteriication or Alcoholysis ....................................................................... 146 2.15.1 Mono- and Diglycerides ................................................................ 146 2.15.1.1 Monoglyceride Derivatives ............................................ 148 2.15.2 Polyglycerol Ester .......................................................................... 150 2.15.3 Propylene Glycol Monoester .......................................................... 152 Blending ...................................................................................................... 152 Deodorization.............................................................................................. 153 2.17.1 Operating Variables ....................................................................... 154

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ix

2.17.1.1 Vacuum ........................................................................... 154 2.17.1.2 Temperature.................................................................... 154 2.17.1.3 Stripping Steam .............................................................. 155 2.17.1.4 Retention Time ............................................................... 156 2.17.2 Deodorization Systems .................................................................. 156 2.17.2.1 Batch ............................................................................... 156 2.17.2.2 Semicontinuous Deodorization ...................................... 157 2.17.2.3 Continuous Deodorization ............................................. 158 2.17.3 Deodorizer Heating Systems ......................................................... 159 2.17.4 Deodorization Process Control ...................................................... 160 2.17.5 Deodorizer Distillated ................................................................... 161 2.18 Finished Fats and Oils Handling................................................................. 164 2.18.1 Protection against Oxidative Deterioration ................................... 164 2.18.1.1 Nitrogen Blanketing ....................................................... 164 2.18.1.2 Temperature Control ...................................................... 165 2.18.1.3 Light Control .................................................................. 166 2.18.1.4 Storage Time .................................................................. 166 2.18.1.5 Antioxidant Addition ...................................................... 166 2.18.1.6 Synergistic Antioxidant Mixtures .................................. 168 2.18.2 Protection against Contamination.................................................. 169 2.19 Plasticization ............................................................................................... 170 2.19.1 Plasticity of Edible Fats and Oils ................................................... 170 2.19.1.1 Product Composition ...................................................... 170 2.19.1.2 Crystal Size .................................................................... 171 2.19.1.3 Supercooling................................................................... 171 2.19.1.4 Mechanical Working ...................................................... 172 2.19.1.5 Gas Incorporation ........................................................... 172 2.19.2 Solidiication Apparatus Evolutions .............................................. 172 2.19.3 Shortening Plasticization Process .................................................. 174 2.19.4 Liquid Shortening Crystallization ................................................. 176 2.19.5 Margarine Plasticization Process................................................... 177 2.19.5.1 Stick Margarine .............................................................. 180 2.19.5.2 Soft-Tub Margarine ........................................................ 180 2.19.5.3 Whipped-Tub Margarine ................................................ 181 2.19.5.4 Liquid Margarine ........................................................... 181 2.19.5.5 Industrial Margarines ..................................................... 182 2.19.6 Tempering ...................................................................................... 182 2.19.6.1 Quick Tempering ............................................................ 183 2.20 Flaking ........................................................................................................ 185 2.20.1 Chill Rolls ...................................................................................... 186 2.20.2 Flake Crystallization...................................................................... 186 2.20.3 Flaking Conditions ........................................................................ 186 2.21 Powdered and Beaded Fats ......................................................................... 187 2.21.1 Spray Cooling ................................................................................ 188

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Contents

2.21.2 Flake Grinding ............................................................................... 188 2.21.3 Spray Flaking and Grinding .......................................................... 188 2.22 Salad and Cooking Oils Packaging............................................................. 189 2.23 Bulk Oil Shipments ..................................................................................... 189 2.23.1 Contamination................................................................................ 190 2.23.2 Overheating .................................................................................... 190 2.23.3 Air Exposure .................................................................................. 190 References ......................................................................................................... 191 Chapter 3 Fats and Oils Analysis ........................................................................................... 197 3.1 3.2

3.3

Introduction ................................................................................................. 197 Nonfatty Impurities ..................................................................................... 198 3.2.1 Moisture Analysis .......................................................................... 198 3.2.1.1 Hot Plate Method ........................................................... 198 3.2.1.2 Air Oven Method ........................................................... 199 3.2.1.3 Vacuum Oven Method.................................................... 199 3.2.1.4 Karl Fisher Method ........................................................ 199 3.2.1.5 Skillet Moisture .............................................................. 199 3.2.2 Impurities Analysis ........................................................................200 3.2.2.1 Insoluble Impurities........................................................200 3.2.2.2 Filterable Impurities (Standard Disk Method) ...............200 3.2.2.3 Turbidimeter Impurities .................................................200 3.2.3 Trace Metals Analysis.................................................................... 201 3.2.4 Soap Analysis................................................................................. 201 Melting, Solidiication, and Consistency .................................................... 201 3.3.1 Melting Point Analysis...................................................................202 3.3.1.1 Capillary Melting Point ..................................................202 3.3.1.2 Softening Point ...............................................................202 3.3.1.3 Slipping Point .................................................................202 3.3.1.4 Wiley Melting Point ....................................................... 203 3.3.1.5 Mettler Dropping Point .................................................. 203 3.3.2 Solid–Liquid Relationships ............................................................ 203 3.3.2.1 Solids Fat Index ..............................................................204 3.3.2.2 Solids Fat Content ..........................................................204 3.3.2.3 Differential Scanning Calorimetry Fat Solids Content ...........................................................................206 3.3.3 Solidiication Analysis ...................................................................207 3.3.3.1 Titer ................................................................................207 3.3.3.2 Quick Titer .....................................................................207 3.3.3.3 Congeal Point .................................................................207 3.3.3.4 Cloud Point .....................................................................208 3.3.3.5 Cold Test .........................................................................208 3.3.3.6 Chill Test ........................................................................208

Contents

3.3.4

3.4

3.5

3.6

3.7

3.8

xi

Consistency Analysis .....................................................................208 3.3.4.1 Consistency Ratings .......................................................209 3.3.4.2 Penetrations ....................................................................209 Composition Analysis ................................................................................. 210 3.4.1 Saponiication Value ...................................................................... 211 3.4.2 Iodine Value ................................................................................... 211 3.4.3 Refractive Index ............................................................................. 212 3.4.4 Fatty Acid Composition ................................................................. 213 3.4.5 Calculated Iodine Value ................................................................. 214 3.4.6 Glyceride Structure ........................................................................ 215 3.4.7 Emulsiier Analysis ........................................................................ 215 3.4.8 Antioxidant Analysis ..................................................................... 216 3.4.9 Tocopherol Analysis ...................................................................... 216 Flavor, Rancidity, and Stability ................................................................... 217 3.5.1 Flavor Analysis .............................................................................. 217 3.5.1.1 Sensory Evaluations ....................................................... 218 3.5.1.2 Volatile Flavor Analysis ................................................. 219 3.5.2 Rancidity Analysis ......................................................................... 219 3.5.2.1 Peroxide Value................................................................ 219 3.5.2.2 Anisidine Value .............................................................. 220 3.5.2.3 Free Fatty Acid and Acid Value ..................................... 220 3.5.2.4 Smoke Point.................................................................... 221 3.5.3 Stability Analysis ........................................................................... 221 3.5.3.1 Active Oxygen Method................................................... 222 3.5.3.2 Oil Stability Index .......................................................... 223 3.5.3.3 Schaal Oven Test ............................................................ 223 3.5.3.4 Pastry Flavor Test ...........................................................224 Color and Appearance.................................................................................224 3.6.1 Color............................................................................................... 225 3.6.1.1 Wesson Color Method .................................................... 225 3.6.1.2 Lovibond (British Standard) .......................................... 225 3.6.1.3 Spectrophotometric Color Method for Oils ................... 226 3.6.1.4 Automatic Tintometers ................................................... 226 3.6.1.5 FAC (Fatty Acid Committee) Method............................ 226 3.6.1.6 Gardner Color................................................................. 227 3.6.1.7 Chlorophyll ..................................................................... 227 3.6.1.8 Coloring Agents Determination ..................................... 227 3.6.2 Appearance .................................................................................... 227 3.6.2.1 Product Appearance Ratings .......................................... 227 Reining and Bleaching ............................................................................... 228 3.7.1 Reining Loss ................................................................................. 228 3.7.2 Neutral Oil and Loss ...................................................................... 229 3.7.3 Bleaching Analysis ........................................................................ 229 Performance Testing ................................................................................... 229 3.8.1 Creaming Volume .......................................................................... 230

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3.8.2 Pound Cake Test ............................................................................ 231 3.8.3 Icing Volume .................................................................................. 231 3.8.4 White Layer Cakes......................................................................... 232 3.8.5 Crème Filling Test.......................................................................... 232 3.8.6 Cake Mix Evaluation ..................................................................... 233 3.8.7 Puff Pastry Testing......................................................................... 233 3.8.8 Restaurant Deep-Fat Frying Evaluation ........................................ 233 3.8.9 Ice Cream Bar Coating Evaluation ................................................ 234 3.9 Nonstandardized Methods .......................................................................... 234 References .........................................................................................................260 Chapter 4 Fats and Oils Formulation...................................................................................... 263 4.1 4.2

4.3

4.4

4.5

Introduction ................................................................................................. 263 Oils and Fats Characteristics ...................................................................... 265 4.2.1 Saturated Fatty Acids ..................................................................... 265 4.2.1.1 Short-Chain Fatty Acids................................................. 267 4.2.1.2 Medium-Chain Fatty Acids............................................ 267 4.2.1.3 Long-Chain Fatty Acids ................................................. 268 4.2.2 Unsaturated Fatty Acids................................................................. 269 4.2.2.1 Monounsaturated Fatty Acids ........................................ 269 4.2.2.2 Polyunsaturated Fatty Acids .......................................... 270 4.2.3 Isomerized Fatty Acids .................................................................. 273 4.2.3.1 Positional Isomers .......................................................... 273 4.2.3.2 Trans Fatty Acids ........................................................... 273 4.2.3.3 Conjugated Linoleic Fatty Acid (CLA) .......................... 274 Palatability .................................................................................................. 275 4.3.1 Oxidation ....................................................................................... 276 4.3.1.1 Flavor Reversion .............................................................280 4.3.1.2 Antioxidants ................................................................... 281 4.3.2 Hydrolysis ...................................................................................... 283 4.3.3 Mouth Feel ..................................................................................... 283 Physical Characteristics .............................................................................. 285 4.4.1 Fat Crystal Habit ............................................................................ 285 4.4.2 Fat Plasticity................................................................................... 288 4.4.3 Solid–Liquid Relationships ............................................................ 289 4.4.3.1 Hydrogenation ................................................................ 289 4.4.3.2 Random Interesteriication ............................................. 291 4.4.3.3 Directed Interesteriication............................................. 295 4.4.3.4 Fractionation................................................................... 295 Nutritional Considerations .......................................................................... 297 4.5.1 Nutritional Facts Panel ................................................................... 298 4.5.2 Health Claims ................................................................................ 299 4.5.3 2005 Dietary Guidelines for Americans........................................300

Contents

xiii

4.5.4 Package Ingredient Statement ........................................................300 Basestock System ........................................................................................ 301 Solids–Liquids Characteristics ...................................................................302 4.7.1 Wide Plastic-Range Fats and Oils Products .................................. 305 4.7.2 Steep Solid Fat Index Slopes..........................................................308 4.7.3 Liquid Opaque or Pumpable Products ........................................... 311 4.8 Emulsiication ............................................................................................. 312 4.8.1 Mono- and Diglycerides ................................................................ 314 4.8.2 Propylene Glycol Esters ................................................................. 316 4.8.3 Sorbitan Esters ............................................................................... 317 4.8.4 Polysorbate Fatty Acid Esters ........................................................ 317 4.8.5 Polyglycerol Esters ......................................................................... 318 4.8.6 Lactated Esters ............................................................................... 318 4.8.7 Lecithin .......................................................................................... 319 4.8.8 Emulsiier Selection Methods ........................................................ 320 4.8.8.1 Hydrophilic/Lipophilic Balance System ........................ 320 4.8.8.2 Emulsiier Functionality Traits....................................... 323 4.8.8.3 Emulsiier Selection Procedure ...................................... 324 4.9 Product Development .................................................................................. 325 4.9.1 Application Product Development ................................................. 325 4.9.2 Analytical Development ................................................................ 327 4.9.2.1 Solids Fat Index Calculations ......................................... 327 4.9.3 Triglyceride Replication................................................................. 328 4.10 Source Oils and Fats Interchangeability ..................................................... 333 4.11 Reduced Trans Fatty Acid Formulation ...................................................... 334 4.12 Essential Fatty Acid Fortiication ............................................................... 337 4.12.1 Essential Fatty Acid Sources ......................................................... 337 4.12.2 Omega-3 Fortiied Products ........................................................... 338 References ......................................................................................................... 339 4.6 4.7

Chapter 5 Shortening Types ................................................................................................... 347 5.1

Introduction ................................................................................................. 347 5.1.1 Historical Background ................................................................... 347 5.1.2 Source Oils..................................................................................... 351 5.1.3 Shortening Product Forms ............................................................. 355 5.2 Plasticized Shortening Applications ........................................................... 355 5.3 Liquid Shortening Applications .................................................................. 357 5.4 Flakes, Chips, and Powdered Shortening Applications .............................. 358 References ......................................................................................................... 359 Chapter 6 Baking Shortenings................................................................................................ 361 6.1

Introduction ................................................................................................. 361

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Contents

6.2 All-Purpose Shortenings ............................................................................. 363 6.3 Emulsiied All-Purpose Shortening ............................................................ 368 6.4 Retail Cake Mix Shortenings ...................................................................... 370 6.5 Specialty Bakery Cake Shortenings............................................................ 373 6.6 Liquid Cake Shortening .............................................................................. 374 6.7 Icing and Filling Shortenings...................................................................... 376 6.8 Icing Stabilizers .......................................................................................... 378 6.9 Bread Shortening ........................................................................................ 379 6.10 Liquid Bread Shortenings ........................................................................... 381 6.11 Sweet Yeast-Raised Dough Shortenings ..................................................... 383 6.12 Cookie Shortenings ..................................................................................... 384 6.13 Cookie Filler Shortenings ........................................................................... 384 6.14 Pie Crust Shortenings.................................................................................. 386 6.15 Biscuit Shortenings ..................................................................................... 387 6.16 Danish Pastry Roll-In Shortenings ............................................................. 389 6.17 Puff Paste Roll-In Shortening ..................................................................... 392 6.18 Shortening Chips......................................................................................... 394 6.19 Cracker Shortenings .................................................................................... 395 References ......................................................................................................... 396 Chapter 7 Frying Shortenings ................................................................................................ 399 7.1 7.2 7.3

Introduction ................................................................................................. 399 Frying Shortening Additives .......................................................................402 Selection of Frying Shortening ...................................................................404 7.3.1 Product Characteristics ..................................................................405 7.3.2 Frying Life .....................................................................................405 7.3.3 Shelf Life........................................................................................406 7.4 Foodservice Deep-Fat Frying Shortening Applications .............................407 7.4.1 Foodservice All-Purpose Shortening ............................................409 7.4.2 Animal–Vegetable Blended Frying Shortening ............................. 410 7.4.3 Heavy-Duty Vegetable Frying Shortenings ................................... 410 7.4.4 Liquid Frying Shortenings ............................................................. 411 7.4.5 Trait-Enhanced Vegetable Oils ...................................................... 412 7.5 Foodservice Pan and Grill Shortenings ...................................................... 414 7.6 Bakery Frying Shortening Applications ..................................................... 416 7.6.1 Cake Donut Shortenings ................................................................ 417 7.6.2 Yeast-Raised Fried Products .......................................................... 419 7.6.3 Fried-Pie Shortenings .................................................................... 419 7.7 Snack Frying Shortening Applications ....................................................... 420 7.7.1 Nut Meats Oil Roasting ................................................................. 422 References ......................................................................................................... 422

Contents

xv

Chapter 8 Dairy Analog Shortenings ..................................................................................... 425 8.1 Introduction ................................................................................................. 425 8.2 Nondairy Creamer ...................................................................................... 426 8.3 Whipped Topping........................................................................................ 429 8.4 Cheese Analog ............................................................................................ 431 8.5 Frozen Dessert or Mellorine ....................................................................... 432 8.6 Sour Cream Analog and Dip Bases ............................................................ 433 8.7 Fluid Milk Analogs ..................................................................................... 434 8.8 Sweetened Condensed Milk Analogs ......................................................... 434 References ......................................................................................................... 436 Chapter 9 Household Shortenings .......................................................................................... 437 9.1 Introduction ................................................................................................. 437 9.2 Household Shortening Development........................................................... 437 9.3 Household Shortening Product Requirements ............................................ 439 9.4 Household Shortening Formulation ............................................................440 9.5 Household Shortening Plasticization ..........................................................444 9.6 Household Shortening Packaging ...............................................................444 References ......................................................................................................... 445 Chapter 10 Margarine............................................................................................................... 447 10.1 10.2 10.3

10.4 10.5

Introduction ................................................................................................. 447 Margarine Development.............................................................................. 447 Margarine Formulation ............................................................................... 453 10.3.1 Milk Products or Protein ............................................................... 453 10.3.2 Emulsiiers ..................................................................................... 454 10.3.3 Flavoring Materials ........................................................................ 454 10.3.4 Preservatives .................................................................................. 455 10.3.5 Vitamins and Color ........................................................................ 455 10.3.6 Supplements for Health Claims ..................................................... 456 10.3.7 Margarine Oils and Fats ................................................................ 456 Low-Fat Margarine or Spread ..................................................................... 457 Consumer Margarine Oil Formulations ...................................................... 459 10.5.1 Margarine Oil Formulations with Hydrogenated Oils................... 459 10.5.2 Margarine Oil Formulation with Interesteriied Oils .................... 461 10.5.3 Margarine Oil Formulation with Fractionated Oils.......................464 10.5.4 Margarine Oil Formulation with Unmodiied Oils .......................464

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10.6 10.7

Industrial Margarine Formulations .............................................................465 Margarine and Spread Preparation .............................................................466 10.7.1 Stick Margarine or Spread ............................................................. 467 10.7.2 Soft Tub Margarine or Spread .......................................................468 10.7.3 Whipped Tub Margarine or Spread ...............................................469 10.7.4 Liquid Margarine ...........................................................................469 10.7.5 Industrial Margarines or Spreads ..................................................469 References ......................................................................................................... 470

Chapter 11 Liquid Oils ............................................................................................................. 473 11.1 11.2 11.3 11.4 11.5 11.6

Introduction ................................................................................................. 473 Development of Liquid Oils ........................................................................ 474 Cooking and Salad Oil Sources .................................................................. 476 Retail Consumer Oils .................................................................................. 479 Industrial Salad Oil Applications................................................................ 481 Mayonnaise ................................................................................................. 482 11.6.1 Mayonnaise Ingredients ................................................................. 483 11.6.1.1 Salad Oil ......................................................................... 483 11.6.1.2 Vinegar ........................................................................... 485 11.6.1.3 Eggs ................................................................................ 485 11.6.1.4 Flavoring Ingredients ..................................................... 485 11.6.2 Mayonnaise Processing.................................................................. 486 11.7 Spoonable Salad Dressing ........................................................................... 487 11.8 Pourable Salad Dressings ............................................................................ 488 11.8.1 French Dressing ............................................................................. 489 11.9 High-Stability Oils ...................................................................................... 490 11.9.1 Processed High-Stability Oils ....................................................... 490 11.9.2 Plant Breeding................................................................................ 490 11.9.3 High-Stability Oil Applications ..................................................... 491 References ......................................................................................................... 492 Chapter 12 Quality Management ............................................................................................. 495 12.1 Introduction ................................................................................................. 495 12.2 Operating Standards ................................................................................... 496 12.3 Speciications .............................................................................................. 496 12.3.1 Speciications Format .................................................................... 497 12.3.2 Ingredient Speciications ............................................................... 499 12.3.2.1 Ingredient Speciications Format ................................... 501 12.3.3 Packaging Speciications ............................................................... 502 12.3.3.1 Packaging Speciications Format ................................... 503 12.3.4 Product Speciications....................................................................504 12.3.4.1 Product Speciications Format ....................................... 505

Contents

xvii

12.3.5 Customer Instruction Speciications ..............................................506 12.3.5.1 Customer Instruction Speciications Format ..................506 12.3.6 Summary Speciications ................................................................ 508 12.3.6.1 Summary Speciications Format .................................... 508 12.4 Procedures ...................................................................................................509 12.4.1 Procedures Format .........................................................................509 12.4.2 Quality Procedures ........................................................................509 12.4.2.1 Complaint Handling Procedure ..................................... 510 12.4.2.2 Product Recall Procedure............................................... 511 12.4.2.3 Product Identiication Procedures .................................. 513 12.4.2.4 Speciication Change Requisition .................................. 515 12.4.2.5 New Product Approval Procedure ................................. 517 12.4.2.6 Weight Control Program ................................................ 518 12.4.2.7 Quality Cost System ....................................................... 518 12.4.2.8 Label Approval Procedure ............................................. 520 12.5 Methods ....................................................................................................... 521 12.5.1 Methods Format ............................................................................. 522 12.6 Process Control Overview .......................................................................... 524 12.7 Crude Fats and Oils Process Control .......................................................... 526 12.8 Reining Process Control ............................................................................ 527 12.9 Prebleaching Process Control ..................................................................... 530 12.10 Modiication Processes ............................................................................... 532 12.10.1 Hydrogenation Process Control ..................................................... 533 12.10.2 Interesteriication Process Control................................................. 535 12.10.2.1 Random Interesteriication Using Chemical Catalyst .... 536 12.10.2.2 Random Interesteriication Using Enzyme Catalyst ...... 538 12.10.3 Fractionation Process Control ........................................................ 539 12.10.3.1 Winterization Process Control .......................................540 12.10.3.2 Dewaxing Process Control .............................................540 12.11 Postbleach Process Control ......................................................................... 542 12.12 Blending Process Control............................................................................544 12.13 Deodorization Process Control ...................................................................544 12.14 Bulk Shipment Process Control ..................................................................546 12.15 Plasticized Shortening Packaging Process Control .................................... 547 12.16 Liquid Shortening Packaging Process Control ........................................... 550 12.17 Liquid Oils Packaging Process Control ...................................................... 552 12.18 Shortening Flake Process Control Standards ............................................. 554 12.19 Margarine and Spread Process Control Standards ..................................... 556 References ......................................................................................................... 559 Chapter 13 Troubleshooting ..................................................................................................... 561 13.1 13.2

Introduction ................................................................................................. 561 Process Troubleshooting ............................................................................. 563

xviii

Contents

13.2.1 Vegetable Oil Extraction ................................................................ 563 13.2.2 Meat Fat Rendering........................................................................ 566 13.2.3 Crude Oil Storage .......................................................................... 566 13.2.4 Degumming ................................................................................... 570 13.2.5 Caustic Oil Reining: Primary Centrifuge ..................................... 571 13.2.6 Oil Reining: Water Wash .............................................................. 574 13.2.7 Oil Reining: Vacuum Drying........................................................ 575 13.2.8 Prebleaching................................................................................... 575 13.2.9 Hydrogenation ................................................................................ 578 13.2.10 Interesteriication ........................................................................... 580 13.2.11 Postbleaching ................................................................................. 581 13.2.12 Winterization ................................................................................. 582 13.2.13 Dewaxing ....................................................................................... 584 13.2.14 Esteriication .................................................................................. 585 13.2.15 Blending ......................................................................................... 588 13.2.16 Deodorization ................................................................................ 589 13.2.17 Antioxidant Addition ..................................................................... 598 13.2.18 Bulk Railroad Car or Truck Loading ............................................600 13.2.19 Oil Filling and Packaging ..............................................................603 13.2.20 Packaged Liquid Oils: Storage and Transportation .......................604 13.2.21 Shortening Packaging ....................................................................605 13.2.22 Liquid Opaque Shortenings ........................................................... 611 13.2.23 Shortening Flakes .......................................................................... 614 13.2.24 Packaged Shortening: Storage and Transportation ........................ 621 13.2.25 Quality Control Laboratory ........................................................... 622 13.2.26 Edible Fats and Oils: Organoleptic Evaluations ............................ 624 13.2.27 Edible Fats and Oils Formulation .................................................. 627 13.2.28 Edible Fats and Oils: Processed Oil Storage ................................. 629 13.3 Shortening Applications.............................................................................. 629 13.3.1 Baking Shortening ......................................................................... 629 13.3.2 Frying Shortenings ........................................................................ 633 13.4 Margarine and Spread Products ..................................................................644 13.5 Quality Management ................................................................................... 649 References ......................................................................................................... 656 Index ...................................................................................................................... 659

Third Edition Preface The objective of this edition remains the same as the two previous editions — to provide a practical reference for fats and oils processing and formulation for effective food processor, foodservice, and household applications. It is designed to be an information source for personnel and students of fats and oils processing as well as the personnel of the user industries. Most of the additions for this edition are related to nutrition. Dietary recommendations for fat and fatty acids continue to evolve as a better understanding of the role of dietary lipids in human health is gained. Processing and formulation techniques are reviewed to help determine how to achieve the most favorable nutritional characteristics while maintaining functionality for the various food applications. This book was designed to delve into the technical aspects that control the functional characteristics of fats and oils products, how these characteristics can be puriied and/or modiied to perform as needed, and the processing control necessary to produce these characteristics on a continuing uniform basis at the most economical cost. Applications development and quality management begin when the customer’s requirements are identiied and continue through product design, sales, manufacturing, product costing, delivery, and service. A thorough understanding of the functions and properties of the various fats and oils products is the basic key to formulating for the desired attributes. Chapters dealing with the raw materials or source oils and fats, process performance and availability, evaluation techniques, formulation attributes, historic changes, and food applications were designed to provide the elements of formulation. Control of oil processing requires consideration of the problems associated with the properties of the raw materials and each process as well as the real and potential customer problems with the ingredients use. A quality management chapter was included to help establish when a system is in or out of control, and a troubleshooting chapter was included to help identify solutions to problems or at least stimulate the thought process for solving the problem. Fats and oils user industries have a vested interest in the development, processing, and quality control for shortening, margarine, and liquid oil products. The properties of the fat and oil ingredients are key elements in the performance and nutritional characteristics of most prepared food products. Fats and oils products for general use, speciic applications, processes, nutritional contributions, and other functionalities have been successful due to the cooperative development efforts between fats and oil processors and food processors. Therefore, this text focuses on the formulation of fats and oils ingredients for food applications for food processor, foodservice, and household use. Information and materials for this book have been gathered over the past 45 years from patents, trade journals, personal experience, and exposure to many of the industry’s recognized leaders and other individuals who have taken a genuine pride in their work and the product produced.

xix

ChaPTEr 1

raw Materials

1.1 InTroduCTIon Fats and oils are the raw materials for liquid oils, shortenings, margarines, and other specialty or tailored products that are functional ingredients in food products prepared by food processors, restaurants, and in the home. Fats and oils have been used for food and a variety of other applications since prehistoric times, as they were easily isolated from their source. For example, fatty tissues from animals liberate free-loating fats on being boiled, whereas oil can be pressed from olives and oilseeds. Fats and oils found utility because of their unique properties. These ingredients were found to add lavor, lubricity, texture, and satiety to foods. They have also been found to have a major role in human nutrition. Fats and oils are the highest energy source of the three basic foods (carbohydrates, proteins, and fats), carriers for oil soluble vitamins, and many contain fatty acids essential for health that are not manufactured by the human body. Fats and oils occur naturally in a wide range of sources, with each source providing a separate and distinctive material. Hundreds of seeds and fruits contain oil, all animals produce fat, and marine sources also provide oils; however, only a few of these sources are of economic importance. All edible fats and oils are waterinsoluble substances that consist predominantly of glyceryl esters of fatty acids, or triglycerides, with some nonglyceridic materials present in small or trace quantities. The terms fats and oils are used interchangeably, and the choice of terms is usually based on the physical state of the material at ambient temperature and tradition. Generally, fats appear solid at ambient temperatures and oils appear liquid. In the inal analysis, it is the chemical composition that deines the characteristics of the individual fat or oil, which, in turn, determines the suitability of this ingredient in various processes and applications.

1

2

Fats and oils: Formulating and ProCessing For aPPliCations

1.2 SourCES of faTS and oIlS Humans have survived as hunters and gatherers for a majority of their known existence on Earth. It was only during the past 10,000 years that they learned to domesticate plants and animals. During this period, the evolution of cultivated plants has been shaped to the needs of modern humans. Today’s agricultural crops are mankind’s creation. Humans cannot survive without them, nor can the crops that have been developed survive without our care. The combined largest source of vegetable oils is the seeds of annual plants grown in relatively temperate climates. Most of these annual plants not only are cultivated as a source of oil, but are also utilized as protein-rich foods. A second source of vegetable oil is oil-bearing trees. Olive, coconut, and palm oils are extracted from the fruit pulp rather than the seed of the fruit. Palm also has seeds, which provide palm kernel oil. All of the oil-bearing tree fruits require a relatively warm climate (i.e., tropical for coconut and palm and a warm climate for olive trees). Most of the oil-bearing tree fruits and kernels provide the highest oil yields. Oil seeds are obtained from annual plants that must be replanted each year, whereas fruit oils are harvested from trees with long life spans. Olive trees are the most hardy and can survive to be several hundred years old. Coconut trees start to bear fruit after 5 to 6 years and their life expectancy is as long as 60 years. Palm trees start to bear fruit after 4 to 5 years and continue to do so for another 20 years. Edible meat fats are supplied almost entirely by three kinds of domesticated animals: lard from pigs, tallow from cattle and sheep, and milk fat or butter from cows. These animals are raised in the greatest quantities where they thrive the best — in temperate climates. Animal husbandry has evolved to the stage that these domestic animals require not only a temperate climate, but also intensive agriculture to provide a plentiful supply of foodstuffs to produce the desired quality and quantity.

1.3 VEGETaBlE oIl YIEldS Fats and oils are renewable resources. The achievements of agriculture and plant cultivation have made it possible to exceed the demand resulting from world population growth. The major vegetable oil seeds and fruits utilized for edible purposes are listed in Table 1.1 with their typical oil contents, yield per acre of land, and major producing areas.1-3 Palm is unparalleled in oil yield. The palm oil yield of palm trees is 3150 to 3330 pounds per acre, and an additional yield of 350 to 370 pounds per acre of palm kernel oil is obtained from the same fruit bunch. Palm trees yield almost 10 times the soybean oil yield per acre. Most oil seeds are annual crops, and the harvest is seasonal; however, palm oil is a perennial crop with two crops produced per year. Coconut, also with a high oil content and yield, requires 9 to 12 months to mature, but fruit is available each month of the year. Olives mature annually and are the most delicate fruit; extraction must be performed as soon as possible to obtain quality oil. Olives have the lowest yield per acre of all the oils evaluated, even though their

raw materials

Table 1.1

3

Vegetable oils: oil Content, Yield, and Producing areas

oil Source

oil Content, %

oil Yield, lbs/acre

Canola

40–45

647–728

Canada, China, india, France, austria, united Kingdom, germany, Poland, Belgium, italy, luxembourg, republic of ireland, greece, Portugal, spain, denmark, Czechoslovakia, united states

Corn

3.1–5.7

215–390

united states, mexico, Canada, Japan, China, Brazil, south africa, argentina, russia, Commonwealth of independent states (Cis), Belgium, France, italy, germany, spain, united Kingdom

Cottonseed

18–20

185–210

China, russia, united states, india, Pakistan, Cis, Brazil, egypt, turkey, australia

Peanut

45–50

1384–1538

China, india, nigeria, united states, senegal, south africa, argentina

safflower

30–35

545–635

China, india, united states, spain, Portugal

soybean

18–20

456–506

united states, Brazil, argentina, China, india, Paraguay, Bolivia

sunlower

35–45

419–539

russia, argentina, Cis, austria, France, italy, germany, spain, united states, united Kingdom

Producing areas

Oilseeds:

Tree fruits and kernels: Coconut

65–68

350–370

Philippines, indonesia, india, mexico, sri lanka, thailand, malaysia, Vietnam, mozambique, new guinea, ivory Coast

olive

15–35

90–260

spain, italy, greece, tunisia, turkey, morocco, Portugal, syria, algeria, Yugoslavia, Cyprus, egypt, israel, libya, Jordan, lebanon, argentina, Chile, mexico, Peru, united states, australia

Palm

45–50

3150–3330

malaysia, indonesia, China, Philippines, Pakistan, mexico, Bangladesh, Columbia, ecuador, nigeria, ivory Coast

Palm kernel

44–53

350–370

malaysia, indonesia, China, Philippines, Pakistan, mexico, Bangladesh, Columbia, ecuador, nigeria, ivory Coast

oil content is about equivalent to cottonseed and much higher than corn germ. The production of one quart of olive oil requires 1300 to 2000 olives. Three of the four tree oils have the highest oil contents, but soybean, an annual oil seed crop with low oil content, still provides a large part of the vegetable oil production in the world. Corn, with the lowest oil content, is grown in large enough quantities to be the third most utilized vegetable oil in the United States. Canola, an

4

Fats and oils: Formulating and ProCessing For aPPliCations

annual oil seed crop developed and grown for its oil composition, has moved from a virtual unknown to second in oilseed utilization to soybean oil. Canola seed has the second highest oil content and oil yield per acre of all the annual oilseed plants presented in Table 1.1; it is surpassed only by peanut or groundnut oil for oil content and yield.

1.4 aVaIlaBIlITY of faTS and oIlS An important contributor to the availability of fats and oils is the fact that most fats and oils production is controlled by factors other than the demand. Corn and cottonseed oils are clearly byproducts, whereas soybeans are speciically crushed to meet the demands for meal. Sunlower, canola, and peanut plantings are subsidized and controlled by the governments of the major countries producing the oils. Palm kernel oil production is dependent on palm oil requirements, as it is grown in the same fruit bunch. Olive, coconut, and palm oils are all produced from the fruit of trees that have long productive life spans, therefore, their production cannot be adjusted to demand changes from year to year. Animal fats are dependent on meat consumption, and butter output is subject to milk production. Thus, the availability of fats and oils is not geared to demand. Weather is another factor that affects both availability and demand for fats and oils. For example, a hurricane in Malaysia can decrease the oil available on the world market; alternatively, favorable weather in the United States, which produces a soybean crop with maximum yields, will increase the available oil for the world market. Other factors that affect world demand are the Russian sunlower crop, African peanut crop, South American soybeans and cottonseed oil yields, and so forth. This is a one-world market in which variable inputs affect availability and demand, which, in turn, affect the price structure.

1.5 unITEd STaTES uTIlIZaTIon of EdIBlE faTS and oIlS Climate and availability certainly inluenced the eating habits of our ancestors. Inhabitants of central and northern Europe obtained their edible fats from animals, whereas people in southern Europe, Asia, and Africa acquired their edible oils from vegetable sources. The food products developed in these different regions used the available fats and oils products. Consequently, the cuisine of central and northern European countries developed around the use of solid fats, such as butter, lard, and tallow for breads, pastries, and other baked and fried products. Similarly, the diets of inhabitants from warmer climates were developed around the use of liquid oils for their food products, which include many sauces and dressings.4 These trends appear to continue to be the preference of their descendants. Immigrants to the United States brought their food preferences with them and introduced them to others from different regions of the world. Fats and oils technology has further increased the varied and rich American diet by improvement

raw materials

Table 1.2

5

2004/2005 World Vegetable oil Consumption

rank

With u.S. usage

order

oil

Million lbs

Without u.S. usage oil

Million lbs

Consumption, % u.S.

World*

1

Palm

72,292

Palm

71,039

4.7

33.1

2

soybean

69,828

soybean

51,873

67.8

24.2

3

Canola

34,474

Canola

32,569

7.2

15.2

4

sunlower

18,678

sunlower

18,319

1.4

8.5

5

Peanut

11,088

Peanut

10,817

1.0

5.1

6

Cottonseed

10,098

Cottonseed

9,238

3.3

4.3

7

Palm kernel

8,316

Palm kernel

7,787

2.0

3.6

8

Coconut

7,260

Coconut

6,134

4.3

2.9

9

olive

6,270

olive

5,756

1.9

2.7

10

Corna

2,483

Corn

798

6.4

0.4

214,330

100.0

100.0

total Notes:

a

240,787

u.s. production only; * without u.s. consumption.

of existing products and development of new food products. The North American eating habits that resulted have made the United States a consumer of almost every available fat and oil, but at a different rank order than for world production. Table 1.2 compares the United States and world vegetable oil consumption.3 Soybean oil does not enjoy the dominant position in the world market that it has in the U.S. market. Palm oil has becomes the major source of oil in the world, followed by soybean, rapeseed (canola), and sunlower oil. The American consumer is offered these fats and oils in the form of cooking or salad oils; butter, margarine, or spreads; and shortenings or as an ingredient in a prepared food product. The sources of the major fats and oils used in the United States are listed in Table 1.3, which reviews the annual usage of both animal fats and vegetable oils over the past ive decades.3,5,6 These data indicate some distinct trends over the past 55 years: 1. 2. 3. 4. 5. 6. 7. 8.

Individual consumption continues to increase A move away from animal fats to vegetable oils Replacement of previously established fats and oils with different source oils Introduction of new vegetable oils The rise and fall of some individual source oils Source oil changes that relect the results of medical studies Introduction of genetically modiied oil seed varieties And more

Disappearance of fats and oils in the United States has increased to over four times the levels recorded 55 years ago. This increased usage is due to increases in population, personal consumption, food waste, and changes in the food preparation methods. The per capita use of visible fats and oils increased by 39.7 pounds during this period,

6

Fats and oils: Formulating and ProCessing For aPPliCations

Table 1.3

u.S. food fats and oils disappearance and Per Capita Consumption

fats and oils Year

Millions of pounds 1950

1960

1970

1980

577

1743

Coconut

129

172

788

1032

897

983

1126

Corn

223

310

445

673

1149

1630

1685

1445

1225

891

523

851

672

860

79

51

67

58

211

459

514

1

182

299

256

385

1253

Canola

Cottonseed olive Palm Palm kernel

1990

2000

2005 1905

26

53

94

nr

362

256

529

103

62

193

112

197

244

271

1446

3011

6253

9112

12164

16318

17955

64

200

357

359

2050

1889

1645

1023

825

630

722

tallow

156

328

518

995

955

1449

1464

Butter

1062

890

860

814

790

1013

1081

7992

12036

14705

19492

26261

29810

Peanut safflower soybean

100

sunlower lard

total

6719.0

Consumption

58

122

87

Pounds per person

Vegetable oils

24.0

26.7

39.0

44.7

52.5

63.0

75.2

animal fats

21.9

18.5

14.1

12.3

8.5

10.2

10.4

45.9

45.3

53.1

57.0

61.0

73.2

85.6

total

conirming an increase in personal usage either from consumption or waste. The changes in the food fats utilized relect the changing eating habits of Americans in relation to time, place, and frequency of eating. During the periods of high increases, the popularity of convenience and snack foods rose sharply, accompanied by rapid growth in the fast food industry, which relies heavily on deep-fat frying. Fats and oils consumption has been categorized into visible and invisible sources. Visible fats and oils are those isolated from animal tissues, oilseeds, or oil fruits and used for food preparation as shortening, margarine, or liquid oil or for specialty uses. Invisible fats and oils are consumed as part of meats, poultry, eggs, dairy products, ish, fruits, or vegetables and account for approximately 60% of an individual’s fat consumption. The values for pounds per person reported in Table 1.3 are those from visible sources only. A shift from animal fats to vegetable oils began long before 1950. Animal fats dominated the U.S. market until animal fat supply shortages and new process developments helped cottonseed oil gain popularity. In 1950, animal fats were only slightly behind in market share, but 20 years later, in 1970, edible vegetable oils accounted for three fourths of the total and animal fats for only one fourth. This trend has continued, with vegetable oil commanding almost 90% of the U.S. edible oil market in 2005. On a per capita basis, edible vegetable oil consumption increased

raw materials

7

during the second half of the twentieth century from 24 to 75.2 pounds; meanwhile, animal fats usage fell from 21.9 to 10.4 pounds. During this period, cottonseed oil lost its dominant vegetable oil position to soybean oil, due to cottonseed supply shortages and economics surrounding the shortage. Vegetable oils became dominant mainly because of competitive pricing (irst for cottonseed oil and then for soybean oil), increased hydrogenation capacity, consumer preference shifts from butter to margarine, and nutritional concerns. Nutritional issues regarding cholesterol and saturated fats led to the demise of animal fats for food use and helped vegetable oils other than soybean and cottonseed obtain a share of the U.S. market. Canola, corn, olive, sunlower, and saflower oils have all been marketed as oils with more attractive nutritional values, such as lower levels of saturated fat and higher levels of polyunsaturated fat. Now, the 2005 data is beginning to indicate efforts to eliminate trans fatty acids in the diet. Increased usage of palm oil and butter probably indicate efforts by consumers and processors to avoid trans fatty acids.

1.6 CharaCTErIZaTIon of faTS and oIlS The chemical and physical properties of fats and oils are largely determined by the fatty acids that they contain and their position within the triacylglycerol molecule. Chemically, all fats and oils are esters of glycerin and fatty acids; nevertheless, the physical properties of natural fats and oils vary widely because (1) the proportions of fatty acids vary over wide ranges, and (2) the triacylglycerol structures vary for each individual oil and fat. Fats and oils are commonly referred to as triglycerides because the glycerin molecule has three hydroxyl groups where a fatty acid can be attached. All triglycerides have the same glycerin unit, so it is the fatty acids that contribute the different properties. The fatty acid components are distinguished in three ways: (1) chain length, (2) number and position of the double bonds, and (3) position of the fatty acids within the glyceride molecule. Variations in these characteristics are responsible for the chemical and physical differences experienced with edible fats and oils. The structure of a fatty acid may be denoted by a systematic name after the nomenclature of its parent hydrocarbon, by the biochemist system, by its common name, or by a convenient shorthand designation showing the number of carbon atoms and the number of double bonds. The fatty-acid carbon-chain lengths vary between 4 and 24 carbon atoms with up to six double bonds. The most prevalent saturated fatty acids are lauric (C-12:0), myristic (C-14:0), palmitic (C-16:0), stearic (C-18:0), arachidic (C-20:0), behenic (C-22:0), and lignoceric (C-24:0). The most important monounsaturated fatty acids are oleic (C-18:1) and erucic (C-22:1). The essential polyunsaturated fatty acids are linoleic (C-18:2), linolenic (C-18:3), EPA (eicosapentaenoic acid) (C-20:5), and DHA (docosahexaenoic acid) (C-22:6). The triglyceride structure of an edible fat or oil is affected by the fatty acids that are present and the point of attachment of each fatty acid to the glycerin. Triglycerides with three identical fatty acids are called monoacid triglycerides. Triglycerides containing more than one type of fatty acid are called mixed triglycerides. A mixed

8

Fats and oils: Formulating and ProCessing For aPPliCations

triglyceride containing three different fatty acids has three regioisomeric forms and six stereoisomeric forms, depending on which fatty acid is in the beta or middle position (sn-2) of the glycerol portion of the molecule and which fatty acids are in the alpha or outer positions (sn-1 and sn-3). The distribution of the fatty acids is considered to be nonrandom when the saturated fatty acids are positioned predominantly in the sn-1 or sn-3 positions and the unsaturated fatty acids are positioned predominantly in the sn-2 position.7 The fatty acid compositions of natural fats and oils vary signiicantly depending, not only on the plant or animal species, but also within the same species. Among the factors that affect the vegetable oil fatty acid compositions are climate conditions, soil type, growing season, plant maturity, plant health, microbiological conditions, seed location within the lower, and genetic variation of the plant. Animal fat and oil composition varies according to the animal species, diet, health, fat location on the carcass, and maturity.8

1.7 nonGlYCErIdE CoMPonEnTS of faTS and oIlS The primary constituents in crude fats and oils are the triglycerides, but they also contain varying amounts of minor components, many of which signiicantly affect their chemical and physical properties. Exclusive of free fatty acids, crude vegetable oils commonly contain 2% or more nonglyceride substances, and animal fats contain much smaller quantities. These minor components, referred to as the unsaponiiable fraction, consist of phospholipids, tocopherols, sterols, resins, carbohydrates, pesticides, proteins, trace metals, and pigments, such as gossypol, carotene, and chlorophyll. Some, but not all, of the nonglyceride materials are undesirable, therefore, the objective in all edible oil processing is to remove the objectionable impurities with the least possible damage to the desirable constituents. 1.7.1 Phospholipids These compounds are better known to oil processors as phosphatides and are frequently referred to, together with small quantities of carbohydrates and resins, as gums, which have adverse effects on product quality and reined oil yield. Phosphatides are emulsiiers and hinder the separation of oil and water phases in the chemical reining process, interfere with effective bleaching, are catalyst poisons, shorten shelf life, and foul equipment surfaces. Phosphatides consist of polyhydric alcohols esteriied with fatty acids and phosphoric acid, which is combined with a nitrogen-containing compound. The phosphatides are divided into two categories: hydratable and nonhydratable, depending on the effect that water has on them. The hydratable phosphatides (phosphatidylcholine and phosphatidylinositol) can be separated from the oil phase with water. The nonhydratable phosphatides (phosphatidic acid and lysophosphatidic acid) and the calcium and magnesium salts of these acids remain in the oil after water degumming. A typical water degumming process will remove the hydratable phosphatides to a level of 200 ppm (parts per million)

raw materials

Table 1.4 fat or oil

9

fats and oils nonglyceride Components Phosphatides %

Sterols ppm

Cholesterol ppm

Tocopherols ppm

Tocotrienols ppm 86 ± 86

soybean

2.2 ± 1.0

2965 ± 1125

28 ± 7

1293 ± 300

Canola

2.0 ± 1.0

8050 ± 3230

53 ± 27

692 ± 85

—

1.25 ± 0.25

15050 ± 7100

57 ± 38

1477 ± 183

355 ± 355

0.8 ± 0.1

4560 ± 1870

68 ± 40

865 ± 35

30 ± 30 270 ± 270

Corn Cottonseed sunlower

0.7 ± 0.2

3495 ± 1055

26 ± 18

738 ± 82

safflower

0.5 ± 0.1

2373 ± 278

7±7

460 ± 230

15 ± 15

0.35 ± 0.05

1878 ± 978

54 ± 54

482 ± 345

256 ± 218

Peanut olive

< 0.1

100

< 0.5

110 ± 40

89 ± 89

Palm

0.075 ± 0.025

2250 ± 250

16 ± 3

240 ± 60

560 ± 140

tallow

< 0.07

1100 ± 300

1100 ± 300

—

—

lard

< 0.05

1150 ± 50

3500 ± 500

—

—

Coconut

< 0.07

805 ± 335

15 ± 9

6±3

49 ± 22

Palm kernel

< 0.07

1100 ± 310

25 ± 15

3±3

30 ± 30

phosphorus for soybean and canola oils. Pretreatment of good-quality crude oils with phosphoric or citric acid before reining is successful in removing both nonhydratable and hydratable phosphatides to a phosphorus level of approximately 20 to 30 ppm. Two common phosphatides occurring in vegetable oils are the lecithins and cephalins, which may be considered triglycerides that have one fatty acid replaced with phosphoric acid. The gums separated with a water degumming process can be dried for lecithin processing; however, the gums isolated with acid degumming processes are not suitable for standard lecithin because their phosphatide composition differs and they contain the degumming acid. As indicated in Table 1.4, all the seed oils contain signiicant quantities of the phosphatides.9-11 1.7.2 Tocopherols and Tocotrienols Tocols, natural antioxidants found in plant-based oils, include four tocopherol and four tocotrienol isomers, each designated as alpha (α), beta (β), gamma (γ), and delta (δ) depending on the number and position of methyl groups on a chromane ring; they also possess vitamin E activity. The tocopherols have a saturated side chain, whereas the tocotrienols have an unsaturated side chain. These antioxidants inhibit lipid oxidation in foods by stabilizing hydroperoxy and other free radicals and their presence has a major effect on oil lavor quality. The antioxidant activity of tocopherols in foods is least for α-tocopherols, while the β- and γ-isomers have intermediate activities and the δ-isomer is the most active. Tocotrienols are less effective than their corresponding tocopherols.12 The stability of many vegetable oils has been credited to the presence of these natural antioxidants; however, too high a tocopherol level will enhance oxidation of the unsaturated fatty acids.13 Seed oils are the major sources of tocopherols and there seems to be a direct relationship between the degree

10

Fats and oils: Formulating and ProCessing For aPPliCations

of unsaturation and the total tocopherol content, that is, higher tocopherol concentrations are present when the unsaturation level indicates a need to prevent oxidation. The tocotrienols are found predominantly in palm oil and cereal oils, such as barley and rice bran oil. Vitamin E functions in humans as a nonspeciic chain-breaking antioxidant that prevents the propagation of lipid oxidation. With respect to their vitamin E activity, α-tocopherol is the most active compound present, while the activity of the other compounds is: β-tocopherol, 15–40; γ-tocopherol, 1–20; δ-tocopherol, 1; α-tocotrienol, 15–30; β-tocotrienol, 1–5; and γ- and δ-tocotrienol, 1% of that of the α-tocopherol. The natural occurring α-tocopherol has been found 35% more active than that of the synthetic all racemic α-tocopherol.12 Table 1.4 lists the tocopherol and tocotrienol contents of most of the major fats and oils before processing.11,13-15 The natural antioxidant content decreases during each stage of processing, with the highest reduction occurring during chemical reining and deodorization. Reining with caustic can remove as much as 10 to 20% of the tocopherols and tocotrienols, but 30 to 60% can be lost with deodorization or steam distillation. Distillates from deodorized or chemically reined oils have economic value due to the sterol and tocopherol contents that are sources for natural vitamin E, natural antioxidants, and other pharmaceuticals. The fat-soluble natural antioxidants are light yellow to colorless, but acquire a deep red hue with oxidation, which causes a noticeable intensiication of the red–yellow color.8 1.7.3 Sequalene Squalene is an unsaturated hydrocarbon, C30H50, with important biological properties. Sequalene is a low-density compound that is lighter than water with a speciic gravity of 0.855. It can easily produce oxygen by combining with water. It is a metabolic precursor of the entire steroid family. Oxidation of one of the terminal double bonds forms an oxide, which is enzyme catalyzed to lanosterol, and then elaborated into cholesterol and other steroids. A chemopreventive effect of squalene on some forms of cancer has been reported. Sequalene has also been shown to possess moderate antioxidant properties; however, it sustains a signiicant loss of these properties during storage. Shark liver oil is a rich source of squalene and small amounts are found in some vegetable oils. Olive oil and amaranth seed oil are two rich plant sources of squalene. It also is a natural byproduct of natural vitamin A commercial production.16-19 1.7.4 Sterols Sterols are minor components of all natural fats and oils and comprise most of the unsaponiiable matter, the remainder consists essentially of hydrocarbons. The sterols are high melting, colorless, and somewhat inert. It was thought that sterols did not contribute any property to a fat or oil; however, an antipolymerization activity has been identiied for some sterols in heated oils, they can undergo oxidation to form a variety of oxidation products, and they can lower LDL (low-density

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lipoproteins) cholesterol levels in hypercholesterolemic individuals. Caustic reining removes a portion of the sterols, but more effective removal requires fractional crystallization, molecular distillation, or high-temperature steam distillation. Table 1.4 lists the total sterol levels and identiies the cholesterol portion for each of the major fats and oils.11 Cholesterol is the main sterol component of animal fat and ish oil and is found in vegetable oils in only trace amounts. In humans, the liver synthesizes cholesterol, but it is also consumed through the diet. Its presence in the body is essential for life. Being water soluble, cholesterol can only be transported in the body by combining with water-soluble proteins to form lipoproteins. It is the form of these lipoproteins that has been the subject of many investigations involving heart disease. There are several types of lipoproteins that have different densities. These are classiied as high-density lipoproteins (HDL), low-density lipoproteins (LDL), and very lowdensity lipoproteins (VLDL). Elevated levels of LDL and VLDL cholesterol can be oxidized to ultimately form plaque that can build up on artery walls to restrict blood low and cause elevated blood pressure. HDL cholesterol apparently carries cholesterol out of the bloodstream and back to the liver for breakdown and excretion. The levels of serum cholesterol and the LDL and HDL fractions in the blood are inluenced by several factors including age, sex, genetics, diet, and physical activity. Diet and exercise are controllable factors for reducing coronary heart disease risk factors. The general diet guidelines that relate to fats and oils are:21 • Saturated fatty acids increase total, LDL, and HDL cholesterol. Palmitic, myristic and lauric fatty acids increase both LDL and HDL cholesterol, but stearic and the medium-chain fatty acids (6 to 10 carbon atoms) have neutral effects on blood lipids and lipoproteins. • Trans fatty acids have been shown to increase serum LDL cholesterol and some studies have indicated that trans fatty acids tend to lower serum HDL cholesterol. • Monounsaturated and polyunsaturated fatty acids lower serum cholesterol when they replace saturated and trans fatty acids.

Vegetable oil sterols are collectively called phytosterols. Campesterol, stigmasterol, and sitosterol are the best-known vegetable sterols. Vegetable sterols, primarily sitosterol as a fatty acyl ester, have been shown to reduce both serum cholesterol and LDL cholesterol and are promising additions to foods to lower heart disease risk.13 Phytosterols, and to a greater extent phytostanols, inhibit absorption of cholesterol in the intestine, while not being absorbed themselves in signiicant amounts.22 The U.S. Food and Drug Administration (FDA) has approved a health claim for plant sterol/stanols esters: Diets low in saturated fat and cholesterol that include at least 1.3 grams plant sterol esters or 3.4 grams of plant stanol esters, consumed in two meals a day with other foods may reduce the risk of heart disease. Additionally, the claim states that they can reduce cholesterol levels.23 Phytosterols were used as a supplement and as a drug to lower serum cholesterol levels in hypercholesterolemic individuals before the “statin” drugs were introduced. The crystalline nature and poor solubility of free phytosterols limited their use as a

12

Fats and oils: Formulating and ProCessing For aPPliCations

supplement, drug, or in food applications. A major breakthrough occurred when scientist at Raisio Group in Finland discovered that phytostanols fatty acid ester derivatives could be readily incorporated into fatty foods, such as margarine and salad dressings. The phytosterols derived from vegetable oils or “tall oil’ are reined and puriied, hydrogenated to phytostanols, and then esteriied with fatty acids. Stanols derived from tall oil contain primarily sitostanol and campestanol in a ratio of ~92/8; stanols derived from soybean oil contain a sitostanol/campestanol ratio of ~68/32. Both blends appear to have equal eficacy. Clinical studies have shown that stanol esters lower LDL cholesterol levels up to ~14% in adults and children. Phytosterol esters have also been shown to lower serum LDL cholesterol levels in more than 14 eficacy studies. Sterol esters are made by esterifying vegetable oil derived phytosterols with fatty acids; no hydrogenation is required with the sterol esters.22 Commercial sterols are derived from vegetable oils indirectly — soapstock from alkali reining and deodorizer distillate are sources of sterols. Processors distill them from the vegetable oil processing byproducts and market the phytosterol ingredients as free sterols and sterol esters. A pine tree byproduct of the pulp-making process is another source of sterols. Natural sitostanol is rare in plants and the sitostanol used in commercial food applications is produced by catalytic hydrogenation of the two most common plant phytosterols: β-sitosterol and stigmasterol.22 The sterols and stanols are esteriied with fatty acids from vegetable oils, converting them to fatsoluble stanol esters that do not alter the physical properties of food products. Stanol and sterol esters, esteriied with long-chain fatty acids are hydrolyzed into free sterols during digestion in the body. The phytosterols ingredients have been approved for addition to fat-based products, such as spreads, dressings, and low-fat foods like yogurt, cheese, and breakfast cereals. Free sterols incorporate into low-fat foods easier than sterol esters.24 1.7.5 Pigments The color bodies in fats and oils include the carotenes that impart yellow and red colors to the oil, chlorophylls that give it a greenish cast, degraded proteins and carbohydrates that have a brownish cast, gossypol that provides the yellowish color to cottonseed oil, and some other components still not completely identiied, such as the one giving a blue color that is observed occasionally in lard. Beta-carotene, one of several provitaminA compounds, is the main precursor of vitamin A. Its conversion to vitamin A occurs via cleavage of the molecule at the central double bond by the action of the enzyme carotene deoxygenase, which is present in human intestinal mucosa and the liver. The protective action of betacarotene and its oxygenated derivates, known as xanthaphylls, against deleterious effects of radiation on light sensitized cells has been well recognized. This effort has been attributed to the conjugated double bonds capable of quenching singlet oxygen; unfortunately, they also have the capability of forming radicals, which initiate oxidation degradation of oils.12 Carotene concentrations are low in most fats and oils except for palm oil, which contains 0.05 to 0.2%.8 The carotenes are heat sensitive and readily adsorbed by bleaching earths.

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Gossypol, found only in cottonseed oil at about 0.1 to 0.2%, is known to be toxic and affects the color of the oil. Past uses of gossypol as a biologically active agent have included its use as an anticancer agent, as a male birth control drug, and as an herbal medicine to combat bronchitis.25 Cottonseed oil must be chemically reined with caustic soda to remove this pigment. Soybean, canola, and olive oils, plus some tallow fats, have green colors due to chlorophyll or related compounds. The green color from chlorophyll is more prominent when the red and yellow colors are reduced by heat bleaching. Chlorophyll, the green coloring matter of plants, is known to decompose into pheophytins, pheophorbids, and pyropheophorbides, under acidic pH and in the presence of oxygen. The breakdown products are nearly 10 times stronger photosensitizers than the chlorophylls. Singlet oxygen formed during this transfer reacts 1500 times faster with unsaturated fatty acids than ground-state oxygen chlorophyll. Therefore, chlorophylls have a very signiicant impact on oxidative stability and must be removed from oils before they have an opportunity to breakdown and cause irreparable damage.26 1.7.6 Pesticides Pesticides are used to increase agriculture production throughout the world. Studies have shown that a majority of the pesticides applied eventually reach the soil surface, where they gradually spread, translocate to other environments, or eventually degrade. Translocation to oil-bearing plant seeds has also been demonstrated. Processing studies have shown that neither solvent extraction nor bleaching affects the pesticide levels in oils; however, it was found that pesticides are removed by volatilization during deodorization. The use of deodorizer distillates in animal feeds has been forbidden because of the pesticide content.20,27 1.7.7 Trace Metals Plants absorb trace amounts of metals during the growing season and during fats and oils processing. Most are harmful to product quality and human health and reduce the eficiency of the process. Trace quantities of copper, iron, manganese, and nickel substantially reduce the oxidative stability of fats and oils, whereas calcium, sodium, and magnesium reduce the eficiency of the reining, degumming, bleaching, and hydrogenation systems. The metals effects can be diminished by the use of chelating agents at various processing points to sequester the trace metals.28 The most widely used chelating agents are citric and phosphoric acids.

1.8 GEnETICallY ModIfIEd VEGETaBlE oIlS Plant breeding to modify the genetics of crops has been practiced for centuries. Initially, genetic improvements were based on selection from genetic variation in wild and cultivated crops. More recently, plant breeders used crossing and selection techniques to enhance yields, oil contents, and climate adaptation, as well as

14

Fats and oils: Formulating and ProCessing For aPPliCations

to affect changes in oil quality, composition, and resistance to pests or pesticides. Introduction of high-oleic saflower in 1964 and low-erucic acid rapeseed oil, which became known as canola oil in 1978, are examples of successful fatty acid composition modiications using this technology. Mutagenesis, another plant breeding technique where the seed is treated with a chemical or γ radiation to alter its physiological functions, was utilized by the Russians to develop high-oleic sunlower oil. These traditional tools used by plant breeders have been combined with biotechnology to broaden the breeders’ capabilities. The traditional crossing and selection techniques cause thousands of genes to be transferred at each cross, whereas molecular genetic engineering can now transfer or alter a single gene. Genetic engineering can also transfer a gene from one species to another, which is impossible with the traditional methods. The genetic modiication of oilseeds by conventional breeding techniques combined with molecular genetic transformations provides a much broader array of possibilities to improve food products. One of the irst modiied oil compositions produced commercially with this process was high-laurate canola oil. High-laurate canola was engineered by inserting a single gene from the California bay laurel tree, which provides a substantial quantity of lauric fatty acid (C-12:0) in the oil.29 This genetic engineering feat proved that a gene from one plant could be transferred to another to produce an oil with speciic fatty acid groups in selective positions for either performance or nutritional effects. Agronomically, high-laurate canola was a total success, but it failed in the market place. Two reasons were suggested for its failure: (1) potential customers for genetically modiied products were reluctant to commit because of consumer opposition to genetically modiied crops, and (2) the specialty oil was marketed at a premium price, which was twice that of most other oils.30 Genetic varieties have been developed to modify the fatty acid proile of oilseed to create new value-added oils. Regardless of the oilseed variety, most of these efforts have followed the same directions: (1) low saturates for dietary needs, (2) low linolenic for lavor stability, (3) high oleic for health and oxidative stability, and (4) high saturates to replace hydrogenation. Currently, only a few of the trait-enhanced oils have captured any market share. The major reason these improved oils have not found acceptance is the high cost of the oils. Some of the key factors that drive up the costs for these modiied oils are • Lack of competitive ield yields: Most modiied oilseeds provide only about 85 to 95% of the yield potential of the regular oilseed variety. Farmers require a high premium to grow these lower yielding varieties. • Identity preservation systems: Separate handling systems are required at every stage, including seed handling, planting, growing, harvesting, transportation, storage, extraction, and inal processing. • Low trait stability: Environmental effects have caused inconsistent oil compositions in modiied oilseed products.

Efforts to reduce or eliminate trans fatty acids have caused several food companies to change to the trait-enhanced oils to avoid the use of partially hydrogenated

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oils. The increased demand is projected to accept the premium pricing and provide the identity preservation systems required.31 Nutrition presents a tremendous potential for genetically engineered oilseeds since it is an emerging arena. As medical science deines features and beneits desirable in oils for human and animal nutrition, plant geneticists can probably develop plants with the desirable characteristics. Development of oilseeds rich in omega-3 long-chain unsaturated fatty acids have already had some success. Australian researchers have accomplished conversion of α-linolenic to EPA fatty acid with a desaturase gene from the zebra ish and an elongase gene from the nematode. They also inserted both a desaturase and elongase gene from microalga Pavlova salina to synthesize DHA.32 Saflower seed oil containing 65% γ-linolenic omega-6 fatty acid has been developed with commercialization expected in 2008.33 Soybeans, developed with traits from other plants, have increased levels of stearidonic (C-18:4) omega-3 fatty acid, a short chain polyunsaturated fatty acid that acts like EPA (C-20:5) fatty acids in the human body.34 Linseed, a rich source of linolenic and linoleic fatty acids has proved to be a disappointment for genetic engineers. Transgenic plants produced intermediate longer chain fatty acids, but only small quantities of the long-chain EPA and arachidonic fatty acids. Apparently, the endogenous biochemistry of linseed limits production of the long-chain EPA fatty acid.

1.9 SoYBEan oIl Soybean oil is obtained from soybeans, Glycina maxima, which are grown in several countries of the world. Soybeans are native to eastern Asia, where ancient Chinese literature indicates that soybeans have been an important part of their diet for centuries. Even though soybean oil currently fulills over 60% of the U.S. edible fats and oils requirements, it is a relatively new food crop for the United States. Soybeans were grown in the United States as early as 1804, but remained an agricultural curiosity and minor crop for over a century.35 European successes with soybean utilization in soap and cattle feed inluenced similar experimentation in the United States, which led to processing of imported soybeans in 1911 and domestic soybeans in 1915. The early ventures were hampered by dificulties in obtaining a suitable supply of soybeans, a lack of processing experience, and development of a market for the soybean oil and meal. Soybean oil, high in polyunsaturates, linoleic, and linolenic fatty acid, is classiied as a semidrying oil. Initially, soybean oil was identiied as an industrial oil, but as a paint oil it dried slowly and developed “after tack,” whereas as an edible oil it tasted like paint. Despite the lavor and odor deiciencies, World War II shortages drove soybean oil production to 0.3 billion pounds in 1938 and further to 1.3 billion pounds in 1945. Fats and oils processors were incorporating as much soybean oil into formulations as possible to take advantage of the 4 to 9¢ per pound discount over cottonseed oil. In many products, hydrogenated soybean oil blended into a formulation without a noticeable lavor degradation; however, lavor was still the limiting factor for acceptance of soybean as a food oil. The soybean oil lavor problem had to be solved before it would be accepted by the food industry.36

16

Fats and oils: Formulating and ProCessing For aPPliCations

During World War II, German edible oil processors developed a formula or process to cure soybean oil reversion. The process included the addition of citric acid to the deodorized oil, which chelate trace prooxidant metals. Objective lavor and odor evaluations substantiated that trace metals were a signiicant contributor to the soybean oil lavor problem. Other edible fats and oils can tolerate copper and iron in the ppm range, but soybean oil lavor is ruined by as little as 0.5 ppm iron and 0.01 ppm copper. This information caused edible oil processors to immediately adopt metal deactivators, of which citric acid is still the most popular, and they promoted the removal of brass valves and conversion of cold rolled steel deodorizers to stainless steel for processing. Another effective precaution identiied was nitrogen blanketing of all oils during the critical high temperature processing steps, including packaging. Effective preventive measures had been identiied, but investigations still had not determined the cause of the off-lavor development with soybean oil. Circumstantial evidence pointed to the 7 to 8% linolenic fatty acid content. A classic experiment interesteriied 9% linolenic fatty acid into cottonseed oil, which typically contains less than 1% of the C-18:3 fatty acid. Subsequent lavor panels identiied this modiied product as soybean oil. This result presented three alternatives for improving the lavor stability of soybean oil: (1) breed it out, (2) extract it out, or (3) hydrogenate it out. Hydrogenation to reduce the linolenic fatty acid content was chosen as the most practical short-term approach.37 Soybean salad oil with reduced linolenic fatty acid content (3 to 4%) was introduced to the U.S. market in the early 1960s. This product was lightly hydrogenated and subsequently winterized to remove the hard fractions developed during hydrogenation. This soybean salad oil was quickly accepted by the retail salad oil consumers and also industrially as a component of salad dressings, mayonnaise, margarines, and shortenings.38 In the 1970s, improvements in soybean seed handling, oil extraction, and oil processing produced a reined, bleached, and deodorized (RBD) oil that was more acceptable for industrial users and was eventually introduced to the retail market. The processing techniques that helped achieve this improved lavor and oxidative stability and others that followed were: 1. Inactivation of the lipoxygenases enzymes that oxidize the polyunsaturated fatty acids and the phospholipases enzymes that catalyze the conversion of phospholipids to a nonhydratable form during oil extraction.39 2. Degumming to remove phospholipids, both the hydratable and nonhydratable forms. 3. Bleaching to remove oxidation products40 and the chlorophyll pigment that has a role in photosynthesis.41 4. Milder processing temperatures. 5. Use of stainless steel transfer lines and tanks for storage and process vessels.42 6. Metal chelating.43 7. Nitrogen protection for the oil throughout processing.44

Soybean oil has become a popular vegetable oil for foodstuffs due to its nutritional qualities, abundance, economic value, and wide functionality. Usage in the United States has increased more than 12-fold over the past 55 years. Soybean oil has been the dominant oil source in the United States since it exceeded cottonseed

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oil usage in 1950 and lard in 1953; it provided more than 61% of all the oil used for liquid oils, shortenings, margarines, and specialty fats and oils in 2005. 1.9.1 Soybean oil Composition and Physical Properties Soybean oil is a very versatile oil as far as processing and product formulation are concerned in that it (1) reines with a low loss; (2) is a natural winter or salad oil; (3) has heat-sensitive color pigments that deodorize to a red color much less than 1.0 Lovibond; (4) develops large, easily iltered crystals when partially hydrogenated or fractionated; (5) has a high iodine value that permits hydrogenation of basestocks for a wide variety of products; (6) has a tocopherol level of about 1300 ppm as crude and retains more than the 500 ppm level required for oxidative stability; and (7) contains both omega-6 and omega-3 essential fatty acids.45 The triglyceride structure of soybean oil is characterized by an almost total absence of saturated fatty acids in the sn-2 position, random distribution of oleic and linolenic fatty acids on all glycerol positions, and a high proportion of linoleic fatty acid in the sn-2 position.46 The typical characteristics and physical properties for soybean oil are as follows:8,11,14,47-50 Soybean oil Composition and Physical Properties Characteristics

Typical

range

speciic gravity, 25/25°C

0.9175

0.917 to 0.921

refractive index, 25°C

1.4728

1.470 to 1.476

iodine value

131

123 to 139

saponiication number

192

189 to 195

unsaponiiable matter, %

0.6

0.6 to 1.6

titer, °C

24

melting point, °C

–22

–20 to –23

—

–16 to –10

solidiication point, °C

—

Cloud point, °C

–9

—

Cold test, hours

25

—

aom stability, hours

12

12 to 15

oxidative stability index, (110°C), hours

2

2.2 to 3.3 56 to 165

tocopherol content, ppm α-tocopherol

100

β-tocopherol

23

16 to 33

γ-tocopherol

842

593 to 983

δ-tocopherol

363

328 to 411

Fatty acid composition, % C-14:0 myristic

0.1