Membrane Systems in the Food Production. Volume 1 Membrane Systems in the Food Production: Volume 1: Dairy, Wine, and Oil Processing 9783110742992, 9783110742886

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Alfredo Cassano, Enrico Drioli (Eds.) Membrane Systems in the Food Production

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Product-Driven Process Design. From Molecule to Enterprise Edwin Zondervan, Cristhian Almeida-Rivera, Kyle Vincent Camarda,  ISBN ----, e-ISBN ---- Industrial Separation Processes. Fundamentals André B. de Haan, H. Burak Eral, Boelo Schuur,  ISBN ----, e-ISBN ----

Membrane Engineering Enrico Drioli, Lidietta Giorno, Francesca Macedonio (Eds.),  ISBN ----, e-ISBN ----

Membrane Systems in the Food Production Volume 1: Dairy, Wine, and Oil Processing Edited by Alfredo Cassano, Enrico Drioli

Editors Dr. Alfredo Cassano ITM-CNR Institute of Membrane Technology c/o University of Calabria Via P. Bucci 17/C 87036 Rende (CS) Italy Email: [email protected] Prof. Enrico Drioli ITM-CNR Institute of Membrane Technology c/o University of Calabria Via P. Bucci 17/C 87036 Rende (CS) Italy Email: [email protected]

ISBN 978-3-11-074288-6 e-ISBN (PDF) 978-3-11-074299-2 e-ISBN (EPUB) 978-3-11-074307-4 Library of Congress Control Number: 2021933492 Bibliographic information published by the Deutsche Nationalbibliothek The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at http://dnb.dnb.de. © 2021 Walter de Gruyter GmbH, Berlin/Boston Cover image: Albert_Karimov / iStock / Getty Images Plus Typesetting: Integra Software Services Pvt. Ltd. Printing and binding: CPI books GmbH, Leck www.degruyter.com

Contents Dairy, wine, and sugar processing Marcello Alinovi, Germano Mucchetti Chapter 1 Integrated membrane and conventional processes applied to milk processing 3 Geneviève Gésan-Guiziou Chapter 2 Integrated membrane operations in whey processing Youssef El Rayess, Martine Mietton-Peuchot Chapter 3 Integrated membrane processes in winemaking

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E. Ratnaningsih, H. Julian, K. Khoiruddin, D. Mangindaan, I. G. Wenten Chapter 4 Membrane-based beverage dealcoholization 69 Frank Lipnizki, René Ruby Figueroa Chapter 5 Membrane operations in the sugar and brewing industry

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Sourav Mondal, Sirshendu De Chapter 6 Processing of stevioside using membrane-based separation processes Hélène Roux-de Balmann, Sylvain Galier Chapter 7 Electrodialysis in integrated processes for food applications

Vegetable oil processing and aroma recovery José Marchese, Juan J. Torres, Cecilia L. Pagliero, Nelio A. Ochoa Chapter 8 Processing of vegetable oils by membrane technology 215

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Roberto Castro-Muñoz, Grzegorz Boczkaj Chapter 9 Pervaporation in food processing 271 Index

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Dairy, wine, and sugar processing

Marcello Alinovi, Germano Mucchetti

Chapter 1 Integrated membrane and conventional processes applied to milk processing 1.1 Introduction In 2019, more than 395 × 106 tons of milk was produced in the world [1]. Production of fluid milk, dried whole milk, dried skimmed milk, and cheese accounted for 15.4%, 5.3%, 9.7%, and 37.3% of total milk, respectively. The remaining 32.3% of milk was transformed into other products (butter, proteins, fermented milk, etc.). Processing of each of these milk products is traditionally characterized by different operations of separation. Fluid milk stabilization for quality and safety reasons was initially obtained by starting coupling water partial removal by means of heat and mass transfer operations within container heat sterilization of concentrated milk [2]. More than a century went by before fluid milk heat pasteurization became a common practice, and the first standard (61 °C for 30 min) was proposed in the United States [3]. About 65 years went by before cross-flow tangential microfiltration (MF) was industrially applied in France, where the Laiterie de Villefranche sur Saone started to produce the milk called “Marguerite” obtained by mixing raw microfiltered skimmed milk with heat pasteurized cream. Cheese may be considered as the typical result of the selective concentration of some milk components (casein and fat) by separation from the others (whey proteins, lactose, and water) as a consequence of physically, chemically, and microbiologically driven phenomena that occur during cheese making (milk acidification, coagulation, syneresis, etc.). During cheese making, whey is typically separated from the cheese curd by draining the whey fraction through a pierced mold or a cloth, following the enzymatic hydrolysis of the casein micelles and/or by an acidification step. Whey separation can be partially or totally prevented by a preliminary milk preconcentration by ultrafiltration (UF), depending on cheese processes, allowing to obtain a milk permeate, which composition allows for more advantageous applications, e.g. milk powder standardization, than those obtainable from whey. The industrial application of membrane operations to milk processing improved the separation options by introducing new milk products and dairy ingredients in the market, by enhancing the separation specificity (e.g., microbial spores, somatic cells

Marcello Alinovi, Germano Mucchetti, Food and Drug Department, University of Parma, Parco Area delle Scienze 47/A, 43124 Parma, Italy, e-mail: [email protected] https://doi.org/10.1515/9783110742992-001

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(SCs), or native proteins) and efficacy, because of new knowledge about membrane fouling and the introduction of emerging processes such as membrane distillation. The aim of this chapter is to describe the most relevant applications of membrane separation to milk processing, as integrated in the actual manufacturing of some important milk products (fluid milk and cheese) and to compare them with the conventional processes.

1.2 Fluid milk The shelf life of fluid milk is mainly dependent on the type and degree of initial microbial contamination and on the residual enzymatic activity after heat and/or other physical treatment; moreover, the efficacy of milk packaging conditions (clean, ultraclean, or aseptic filling) plays an important role in preventing post-contamination [4, 5]. Pasteurized and extended shelf life (ESL) milk is characterized by the residual presence of a heat-resistant microbial load; for this reason, both pasteurized and ESL milk have to be kept in refrigerated conditions for a relatively short shelf life (up to 30 days), while ultra-high temperature (UHT) and in-bottle sterilized milk are sterile products that can be kept at room temperature for a relatively long shelf life (6 months or more) [5].

1.2.1 MF and bacterial removal The duration and/or the temperature of heat treatment during milk processing can be responsible for high losses of nutritional value and generally unwanted milk changes. An efficacious strategy to extend milk shelf life without modifying these properties is the reduction of raw milk microbial counts by the application of nonthermal treatments [6]. Given the same lethal effect, a lower initial microbial count leads to a lower residual count and to a potentially longer shelf life of the heattreated milk. Centrifugal separation (e.g., bactofugation™) and MF are two competing or synergic operations able to reduce the number of microbial cells contaminating raw milk by separation processes, based on different physical properties, for example, specific gravity (SG) and size, in the order. Bacterial removal from milk by separators, mainly heat-resistant spores, is a relatively old technology [7] applied firstly to fluid milk and then to cheese milk, for example, to hard-cooked Italian cheeses to prevent late blowing defect during ripening [8–10]. Centrifugal separation of microorganisms is mainly based on the SG difference of microbial cells and the continuous phase of milk, as defined by the Stokes law.

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Chapter 1 Integrated membrane and conventional processes

Table 1.1: Composition of milk and characteristics of its particles (dispersion, size, and options of membrane separation). Component

Form of the dispersion of the component

Approximate content

Microorganism

Suspension

1.0% upgrades the classification of “concentrate (WPC)” to “isolate whey protein (WPI)” status.

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The wide range of WPC and WPI containing from 35% to ~90% protein offers a diversity of end uses and market opportunities. At the lower protein end of the range, WPC 35 competes with commodity-produced skimmed milk powder. WPCs containing ~35% protein for instance are used in the manufacture of processed cheese, yogurt, and in various bakery applications. The concentrates are also marketed for use in stews and sauces, because of their thickening properties, and meat patties. Higher protein WPC, on the other hand, are preferred for formula in which industrials wish to achieve a desired ingredient functionality or minimize the amount of nonprotein WPC components added. WPC containing 80% protein (or higher) are for instance used in infant formula.

2.5.1 Pretreatment of whey prior to UF During the past years, several pretreatments of whey have been proposed prior to UF [11]. The majority of them increase the purity of the final concentrates, especially by reducing the residual fat content in cheese wheys; residual fat in cheese wheys, even after skimming by centrifugation, is indeed a factor which limits the upper protein concentration, impairs the functionalities of whey proteins (emulsifying, foaming, and gelling characteristics), and promotes development of off-flavors. Some other pretreatments improve UF performance especially by limiting calcium phosphate precipitation and protein accumulation [12]. Among these pretreatments, some use membrane operations. The first pretreatment of whey, known as the “thermocalcic aggregation process,” was proposed at the end of the 1980s by Pearce [13] and Maubois’s group [14]. This pretreatment relies on calcium addition and pH adjustment under moderate temperature to favor the precipitation of calcium phosphate with residual fat. After several adaptations, the final suggested protocol consists in several steps: whey is first concentrated by UF until a concentration of 4–5, then the pH of the retentate is increased and adjusted to 7.5; the temperature is maintained at 55 °C for 8 min (in order to favor the aggregation of the lipoproteins-Ca); and finally the formed aggregates as well as the small fat globules and bacteria are separated using a 0.1 µm membrane MF. Owing to its high content of phospholipids, whey MF retentate, which represents a volume of no more than 2% of the initial volume of whey [15], has potential as an effective emulsification agent for food applications or cosmetics. The absence of fat in the “clarified” whey (permeate) and high pH strongly reduce the fouling of subsequent UF resulting in longer running time and higher permeation flux. Such a pretreatment of whey accompanied with the introduction of a diafiltration in the UF process allows to easily obtain WPI with 90% protein and high foaming and gelling properties. An adaptation of this pretreatment protocol, comprising calcium addition, pH adjustment, temperature increase, and centrifugation, is applied today to recover proteins with no alteration of their profile from acid wheys.

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For several years now, direct processing of whey by cross-flow MF remains the only pretreatment available for the defatting of whey. MF was shown to adequately remove residual fat without recourse to the use of physicochemical modifications of whey such as addition of calcium or adjustment of pH. Simultaneously, MF removes casein fines and fat thus contributing to an improved quality of the final product. Ceramic membranes with ~0.2 µm mean pore diameter were initially used at ~50 °C for this application. However, due to their high capital costs, they are now replaced by more affordable spiral wound PVDF membranes, which when operating at low temperature (15 °C). Due to the relatively low membrane prices of spiral wound membranes that compensate the increase in installed surface membrane due to the decrease of permeation fluxes, most of the manufacturers

Figure 2.2: UF plant for whey protein concentration (courtesy of SPX Flow Technology SAS, France).

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of protein concentrates today prefer to operate at a lower temperature (90% w/w) in the desired phosphopeptides. The glycomagropeptide (C-terminal part of the κ-casein released in whey by the action of chymosin) was shown to be separated from sodium caseinate using UF membrane. This peptide has numerous uses (action on satiety, inhibition of Escherichia coli cells’ adhesion to intestinal walls, etc.), and in particular it contains no Phe, which makes it suitable for use as a nutritional protein supplement for patients suffering from phenylketonuria, who do not digest protein with phenylalanine due to their lack in the appropriate degrading enzyme.

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The occurrence of many bioactive peptides in bovine milk is now well established [25], but at present, the industrial-scale production of such peptides is limited by a lack of suitable separation technologies. Among them, membrane techniques, such as NF or UF, are used industrially to produce ingredients that contain bioactive peptides based on casein or whey protein hydrolysates and seem to be the best technology available for the enrichment of bioactive peptides. Growth factors such as transforming growth factor β and insulin-like growth factors I and II have been classically separated from whey by means of cationexchange chromatography [27]. However, some recent developments of membrane applications have enabled the recovery of growth factors from whey [28]. Some attention has already been paid to the recovery of the growth factor from bovine colostrum, which typically contains 10 to 15 times the amount of milk in terms of growth factors. MF and UF separations have then been proposed for the extraction of these compounds [24]. Industrial applications of such separations do not exist yet, but when some solid scientific evidence on their bioactivity in humans is developed, a sustainable market can be expected.

2.8 Conclusions – challenges Membrane operations have revolutionized the field of whey processing in many aspects, and have been part of profound changes in the dairy industry worldwide. In the last 40 years, the approach to whey processing and utilization has changed from considering whey as a simple waste to capitalizing on the opportunities that the whey offers for product innovations. Nowadays, industrial processing of whey is a highly specialized, technologically advanced segment of the dairy industry requiring up-to-date knowledge and focused attention. The UF processes, largely used worldwide for the production of protein concentrates and isolates, partially solve the problems of dealing with large volumes of whey or whey permeate in traditional cheese manufactures. Spiral wound polymeric UF membrane has proven to be the most widely adopted and cost-effective separation process for the production of WPCs. NF and in a lesser extent MF enabled the development of wheybased ingredients. Despite the impressive growth of membrane applications in this sector, membrane technologies have still not been fully exploited for the development of added-value ingredients and products, mainly due to commercial constraints such as immature market demand for value-added ingredients, occurrence of alternative technologies, cleaning issues, or introduction of nondairy equivalents of dairy ingredients. Although a wide variety of fascinating new applications of membrane technology in dairy processes are expected in the next decade, the field of membrane science is nowadays facing important challenges worldwide such as shortage of drinking water

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supplies, global warning, and potential global energy crisis. With the reduction of available water and constant rise of energy costs, it is imperative that control of water and energy uses will be a key factor in the development and growth of membranebased processes in the future. In that context, some recent work of Omont et al. [29] carried out on the fractionation of whey proteins pointed out the potentialities of membrane processes compared with chromatographic techniques. Control of fouling and improvements of cleaning steps will undoubtedly remain as a high-priority research domain, whereas development of new membrane or module designs, coupling of separation operations, optimization to face the compromises, and trade-offs to achieve the best performance of the overall fractionation processes might offer interesting alternatives.

References [1] [2] [3] [4]

[5] [6] [7] [8] [9] [10] [11]

[12] [13] [14] [15]

Marshall KR. Industrial fractionation of milk proteins: serum proteins. In: Fox PF, ed. Developments in Dairy Chemistry-1. New York, USA, Applied Science Publishers, 1982. Maubois JL. New applications of membrane technology in the dairy industry. Aus J Dairy Technol 1991, 46, 91–95. Gésan-Guiziou G, Boyaval E, Daufin G. Critical stability conditions in crossflow microfiltration of skimmed milk: Transition to irreversible deposition. J Membrane Sci 1999, 158, 211–222. Aydiner C, Sen U, Topcu S, Ekinci D, Altinay AD, Koseoglu-Imer DY, Keskinler B. Techno-economic viability of innovative membrane systems in water and mass recovery from dairy wastewater. J Membrane Sci 2014, 458, 66–75. Wang YN, Wang R, Li W, Tang CY. Whey recovery using forward osmosis – Evaluating the factors limiting the flux performance. J Membrane Sci 2017, 533, 179–189. Christensen K, Andresen R, Tandskov I, Norddahl B, Du Preez JH. Using direct contact membrane distillation for whey protein concentration. Desalination 2006, 200(1–3), 523–525. Hausmann A, Sanciolo P, Vasiljevic T, Kulozik U, Duke M. Performance assessment of membrane distillation for skim milk and whey processing. J Dairy Sci 2014, 97(1), 56–71. Jeantet R, Schuck P, Famelart MH, Maubois JL. Nanofiltration benefit for production of spray-dried demineralized whey powder. Lait 1996, 76, 283–301. Gernigon G, Schuck P, Jeantet R. Demineralization. In: Fuquay JW, Fox PF, McSweeney PLH, ed. Encyclopedia of Dairy Science, 2nd edition. Vol. 4, London, UK, Elsevier, 2011, 738–743, 2011. Largeteau D (Eurodia). Electrodialysis in food processing. Aarhus seminar. 2009. Pouliot Y, Jelen P. Pretreatments of dairy fluids to minimize long-term membrane fouling. In: IDF, Bulletin of the IDF, ed. Fouling and Cleaning in Membrane Pressure Driven Membrane Processes. 1995, Special Issue, International Dairy Federation, Brussels (B) 9504, 80–93. Maubois JL, Ollivier G. Extraction of milk proteins. In: Damodaran S, Paraf A, eds. Foods Proteins and Their Applications. New York, USA, Marcel Dekker Inc., 1997, 579–595. Pearce RJ. Thermal separation of beta-lactoglobulin and alpha-lactalbumin in bovine Cheddar cheese whey. Aust J Dairy Technol 1983, 38, 144–148. Maubois JL, Pierre A, Fauquant J, Piot M. Industrial fractionation of main whey proteins. IDF Bull 1987, 212, 154–159. Baumy JJ, Gestin L, Fauquant J, Boyaval E, Maubois JL. Technologies de purification des phospholipides du lactosérum. Process 1990, 1047, 29–33.

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[16] Gésan-Guiziou G. Separation technologies in dairy and egg processing. In: Rizvi SSH, ed. Separation, Extraction and Concentration Processes in the Food, Beverage and Nutraceutical Industries, Woodhead Publishing Limited. Cambridge (UK), 2010, Chap. 12, 341–380. [17] Korhonen H, Pihlanto A. Technological options for the production of health-promoting proteins and peptides derived from milk and colostrums. Curr Pharm Des 2007, 13, 829–843. [18] Bonnaillie L, Tomasula PM. Whey protein fractionation. In: Onwulata CI, Huth PJ, eds. Whey Processing, Functionality and Health Benefits. Ames, IA, Blackwell Publishing and IFT Press, 2008, 15–39. [19] Muller A, Daufin G, Chaufer B. Ultrafiltration modes of operation for the separation of alpha-lactalbumin from acid casein whey. J Membrane Sci 1999, 153(1), 9–21. [20] Muller A, Chaufer B, Merin U, Daufin G. Prepurification of alpha-lactalbumin with ultrafiltration ceramic membranes from acid casein whey: Study of operating conditions. Lait 2003, 83(2), 111–129. [21] Bramaud C, Aimar P, Daufin G. Whey protein fractionation: Isoelectric precipitation of αlactalbumin under gentle heat treatment. Biotechnol Bioeng 1997, 56, 391–397. [22] Maubois JL, Fauquant J, Famelart MH, Caussin F Milk microfiltrate, a convenient starting material for fractionation of whey proteins and derivates. The importance of whey and whey components in food and nutrition. In: Proc. of 3rd International Whey Conference, Munich, Germany. Hamburg, B. Behr’s Verlag, 2001, 59–72. [23] Korhonen H, Syväoja EL, Vasara E, Kosunen T, Marnila P Pharmaceutical composition, comprising complement proteins, for the treatment of Helicabacter infections and a method for the preparation of the composition. PCT Patent Application WO98/00150. 1998. [24] Piot M, Fauquant J, Madec MN, Maubois JL. Preparation of “serocolostrum” by membrane microfiltration. Lait 2004, 84, 333–342. [25] Korhonen H. Milk-derived bioactive peptides: From science to applications. J Funct Foods 2009, I, 177–187. [26] Brulé G, Roger L, Fauquant J, Piot M Phosphopeptides from casein-based material. US patent 4358465. 1981. [27] Smithers GW. Isolation of growth factors from whey and their application in food and biotechnology industries – A brief review. Bull Int Dairy Fed 2004, 389, 16–19. [28] Gauthier SF, Poulit Y, Maubois JL. Growth factors from bovine milk and colostrum: Composition, extraction and biological activities. Lait 2006, 86, 99–125. [29] Omont S, Froelich D, Gésan-Guiziou G, Rabiller-Baudry M, Thueux F, Beudon D, Tregret L, Buson C, Auffret D. Comparison of milk protein separation processes by life cycle analysis: Chromatography vs filtration processes. Proc Eng 2012, 44, 1825–1827.

Youssef El Rayess, Martine Mietton-Peuchot

Chapter 3 Integrated membrane processes in winemaking 3.1 Introduction Membrane filtration has been applied to wine for a long time. At present, the clarification cartridges are integrated in bottling units. Subsequently, in a cross-flow filtration mode, microfiltration (MF) membranes were the first to be applied for wine clarification. Today, cross-flow microfiltration (CFMF) is largely used in enology for must, lees, and wine filtration at different membrane cut-off, from 0.2 to 1.2 μm. The development of reverse osmosis (RO) application in must concentration was practically done in parallel with that of MF in clarification [1]. This chapter is an overview of the application of membrane processes to winemaking. The aim is to present both the application of membrane processes in winemaking and a general philosophy of their development from a process engineering point of view. Several examples illustrate this approach, in particular, applications of nanofiltration (NF) and RO membranes. Reduction of alcohol content is studied with different techniques (NF + evaporation, NF + membrane contactor (MC), decrease of sugar content, etc.). Reduction of sugar content of the musts (ultrafiltration (UF) + NF) could be an alternative process to reduce the alcohol content of the wines and to improve their quality. The volatile acidity or malic acid reduction could also be done by coupling two stages of RO. Since the free acids are poorly retained by the membrane, the permeate after the first stage filtration contains free acids, salts, esters, and other small molecules. Once the permeate is neutralized with pH of the targeted acid, it will be retained by the second stage membrane in a salty form. The other components passing through are reinjected in the initial must or wine. The potassium hydroxide is used for neutralization. The proposed processes integrate different steps: two membrane techniques, a membrane process, and a chemical reaction or new developments (rotating membranes, bipolar membranes, etc.). The principal condition for further development of membrane processes in winemaking is a good understanding of membrane techniques, separation techniques, and characterization of the membrane itself and the product (must or wine) to be filtered.

Youssef El Rayess, Department of Agriculture and Food Engineering, School of Engineering, Holy Spirit University of Kaslik, P.O. Box 446, Jounieh, Lebanon, e-mail: [email protected] Martine Mietton-Peuchot, Université de Bordeaux, ISVV, EA 4577, Unité de recherche OENOLOGIE, F-33882 Villenave d’Ornon, France; INRA, ISVV, USC 1366 OENOLOGIE, F-33882 Villenave d’Ornon, France https://doi.org/10.1515/9783110742992-003

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The second constrain, given the complexity and variability of must and wine composition is not trivial and needs a considerable effort at both industrial and research levels. For the same reasons, the coupling of the membrane and other physical–chemical treatments appears to be a promising research domain.

3.2 Cross-flow microfiltration for must, wine, and lees clarification During red or white winemaking, the filtration process is usually involved in several steps of product elaboration. Filtration in winemaking is used to accomplish two main objectives, clarification and microbial stabilization. In clarification, large particles that affect the visual appearance of wine are removed. In microbial stabilization, bacteria or yeasts are removed with the aim of reducing the probability of refermentation or spoilage. The limpidity and the microbiological stabilization of wine are two essential parameters that could affect wine organoleptic quality. The compounds removed by filtration can be classified into three groups according to their size: solutes (1 µm) [2]. Depending on the objectives of the filtration and wine characteristics, the winemakers choose the most adapted technique. Wineries can perform filtration according to two different main technologies, by using precoat or membrane filters. In order to obtain the required wine quality, different types of filtration equipment are available: drum filtration, plate and frame filtration, cartridges, and cross-flow filtration [3]. A filtration process must be efficient in terms of retention and produce adequate flow rates without prejudice to the quality of the wine. These criteria can be difficult to reconcile due to the fouling by the filtering solution over time. The fouling modifies the flow rate and the retention characteristics. CFMF is well implemented in wine cellars. The first trials of CFMF have been conducted in enology at the beginning of the 1980s with unsatisfactory results in terms of wine quality because the used membranes (UF membranes) were not specific to wine filtration. This technique is an attractive process to wine industry for one-step clarification and microbiological stabilization compared with traditional techniques. In order to have a limpid wine, the winemakers implement successive solid–liquid separations using traditional technologies such as centrifugation, filtration on plates, diatomaceous earth filtration, and the use of exogenic additives. The traditional techniques quickly showed its limits in terms of wine quality, wine loss, and its implementation especially in cellars dealing with huge volumes of wines. In addition, the filtration additives have a negative effect on the environment. Their disposal must be done in special waste treatment sites. In addition to a great simplification of the wine processing line, CFMF offers a number of additional advantages such as elimination of earth use and its associated environmental

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problems as well as the combination of clarification, stabilization, and sterile filtration in one single continuous operation. For a long time, the development of the CFMF suffered from the significant fouling of the membranes by wine compounds. The consequence of this is a reduction in permeation rates, affecting the economic viability of the process, and a risk of excessive retention of some components, which may affect the product quality. Crude wine after fermentations is a very complex medium with solute molecules as ions, organic acids, and sugars (1 μm). The filtration of complex solutions as wine are characterized by the coexistence of different fouling phenomena such as adsorption, particle capture, deposit formation, and biofilms. The relative contribution of each phenomenon depends on the nature of the filter media, operating conditions, and fluid characteristics. Hermans and Bredee [4] and Hermia [5] developed four empirical models that explain flux decline kinetics. According to these models, four mechanisms are identified: complete blocking, intermediate blocking, standard blocking, and cake formation. In wine filtration, El Rayess et al. [6] showed the coexistence of different fouling mechanisms by a single log–log plot where the log(dt/dV) represented the hydraulic resistance and log (d2t/dV2) represented the variation of the resistance with the filtered volume. Several studies have been conducted in the literature in order to identify the wine molecules responsible for membrane fouling, the fouling mechanisms, and the methods to limit or control membrane fouling. Studies were initiated in mid1980s and were focused on the identification of the most suitable membrane pore size for wine filtration. Studies [7, 8] showed that 0.2 µm as average pore size presented the best results in terms of permeate flux and wine quality. Afterward, works were oriented in order to identify wine compounds responsible of membrane fouling. It was mainly reported in the involvement of polysaccharides and polyphenols in membrane fouling. Polysaccharides and polyphenols belong to wine colloids. The colloid dispersions in wine during filtration may be stable or unstable depending on several physicochemical parameters (pH, surface interactions, hydrodynamics conditions, etc.). The importance of fouling by colloids is dependent on their composition and their complexes and aggregates. Adsorption, adhesion, and aggregation of colloids in liquid media result from a complex balance between their interactions that occur between the different colloids, surfaces, and solvents. Interactions of Lifshtitz–van der Waals, electrostatic repulsion, polar interactions, and forces associated with Brownian motion are the main interactions involved in the cited phenomena. Colloidal systems have very changeable properties depending on their volume fraction or concentration. They can switch from a diluted stable dispersion to unstable state, which results in aggregated colloids. The colloidal stability, which is explained by DLVO theory, is defined by their ability not to aggregate. According to this theory, the stability of

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Youssef El Rayess, Martine Mietton-Peuchot

colloidal suspensions is determined by the balance between attractive energy (van der Waals) and electrostatic repulsion. During wine filtration, the concentration of retained compounds increases at the membrane surface leading to aggregation and eventually membrane fouling. Vernhet et al. [9] studied the effect of wine polysaccharides on an organic polyethersulfone (PES) membrane fouling. They showed that the effects of polysaccharides on fouling are not similar due to the nature of polysaccharides fraction involved in the fouling. It was shown that the pectic polysaccharides of low molecular weight (rhamnogalacturonan type II: RG-II) have no noticeable effect on the permeation flux, whereas mannoproteins play a crucial role in reducing the fluxes. The researchers noticed that the membrane fouling by a given wine is not directly related to its total polysaccharides content but rather to the composition, structure of these polysaccharides, and the balance between different groups of polysaccharides [10]. In 2009, Ulbricht et al. [11] demonstrated that different membrane materials exhibit different levels of polysaccharides adsorption. They showed that larger amounts of polysaccharides were adsorbed on hydrophilic membranes than on hydrophobic membranes. In 2011, El Rayess et al. [12] showed that polysaccharides formed a compact gel layer on the membrane surface and it is dependent on transmembrane pressure. Phenolic compounds have a much more important affinity for membranes than the polysaccharides and there are both quantitative and qualitative differences between the different materials tested. It is worth to notice that polyphenols are amphipathic molecules with hydrophobic aromatic rings and hydrophilic phenolic hydroxyl groups. So, their adsorption involves both hydrophobic effects and the formation of hydrogen bonds. The preferential adsorption of phenolic compounds with low polarity suggests the predominance of hydrophobic interactions [2]. It was shown that an increase in polyphenol concentration in wine leads to a decrease in membrane permeability and thus an increase in membrane fouling [6]. Suspended particles such as yeasts, bacteria, and cell debris play also a role in membrane fouling. Boissier et al. [13] proved that the increase in the total resistance related to yeast deposition is due to the compaction of the cake layer on the surface of the membrane. They also found that fouling is governed more by fine particles (lactic bacteria and colloidal aggregates) than yeast. In 2011, El Rayess [14] showed that yeasts may protect the membrane from colloids fouling whether by forming a secondary membrane or by disturbing the pectic gel layer to be uniformly installed on the membrane surface. To control membrane fouling, it is important to adjust the operating conditions of wine CFMF. Critical flux can be a key parameter of the control of membrane fouling as it is depending on the hydrodynamics and physicochemistry (membrane/solutes interactions) at the same time. El Rayess et al. [12] studied the critical flux for irreversibility (Jci) during wine CFMF. The critical flux for irreversibility (Jci) is defined as the permeate flux above which an irreversible fouling appears on the membrane surface. The method used to determine Jci is the square wave barovelocimetry developed by Espinasse et al. [15]; this method also enables the distinction between

Chapter 3 Integrated membrane processes in winemaking

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reversible and irreversible fouling with the determination of reversible (Rrf) and irreversible (Rif) resistance, respectively. If the permeate flux is the same between these two steps, the fouling associated is considered as totally reversible. If it is not the case, the fouling associated is considered as partly irreversible and the critical flux for irreversibility is determined at the last step where fouling is totally reversible. For all tested macromolecules (tannins, pectins, and mannoproteins) and associate concentrations and in the range of tested pressures (200–1,000 mbar), it was found impossible to determinate a value of the critical flux for irreversibility Jci. This was not the case for filtered wine, where Jci was found beyond 1,000 mbar (Jci ≥ 1.4 × 10−4 m s–1). To improve the efficiency of the filtration process and maintain the state of cleanliness of the membrane filtering surfaces at an acceptable level during the filtration process, most of filtration devices are equipped with a reverse filtering system. Back-flushing, backwashing, and back-pulsing are all methods of operation in which the transmembrane pressure is periodically inverted by the use of a secondary pump, so that permeate flows back into the feed, lifting the fouling layer from the surface of the membrane. The main difference in the methods is mainly the time frame in which the process operates. Technically, the back-pulsing process is very similar to back-flushing or backwashing that is widely used for commercial applications. However, the fundamental difference between a back-pulse and a back-flush is the force and time used to lift accumulated deposits off the membrane. Generally in back-flushing, flow reversal occurs for a few seconds once every several minutes, while back-pulsing occurs at a higher frequency and the pulses applied for a very short time (nhexanol>water. This membrane-aroma affinity resulted in a higher sorption ability of the molecule in the membrane, and hence facilitated permeation. These findings were in agreement with the Hansen solubility parameters [63]. Lemon is widely defined by its multiple aromas, fragrances, and essential oils. In fact, lemon is recognized as one of the most enriched sources of essential oils together with other citric products including bergamot, lime, sweet orange, tangerine, and mandarin [82]. Among the wide range of aromas, lemon contains mainly terpenes, such as limonene, ɣ-terpinene, p-cymene, and α-citral [83], to mention just a few of them. Knowing its potentiality as a source of terpenes, lemon juice was subjected to pervapotive separation of α-pinene, β-pinene, and limonene. Rafia and coworkers utilized a POMS polymer membrane which showed an enhanced β and permeation values when driving force increased [67]. Contrary to PDMS membranes, temperature increment in POM membranes preferentially promoted water transport compared to aromas, compromising the β factor. Therefore, the recovery of terpenes was recommended to be done at low temperatures. A large list of chemical solutes (e.g., carboxylic acids, pyrroles, pyridines, and chlorogenic acids) is responsible for the characteristic taste and aroma of coffee [84]. This product is recognized, commercialized, and consumed worldwide. Of course, the research has recently exerted interest in this typical product for the extraction of chemicals. In this case, 2,3-butanedione and 2-5-dimethyl pyrazine were intentionally separated via organophilic PV (PDMS Pervaptech BV membrane). Weschenfelder et al. [73] notified that the commercial membrane demonstrated high selectivity for 2,3butanedione and 2-5-dimethyl pyrazine according to the β values of 45 and 42, respectively. Together with the acceptable selectivity, the membrane also exhibited a suitable permeate flux of about 0.432 kg m−2 h−1. In addition to the exploration of fruits and natural extracts for the extraction of aromas and fragrances, different wastes, residues, and by-products from agro-foods are pointed out as feasible feedstock of these high added value organics based on the recent trends in food waste valorization for the manufacture of chemicals and materials [15, 85]. These wastes are inherently the result of the various food processing treatments, such as washing, peeling, pressing, among others [86, 87]. In 2002, Souchon and coworkers pioneered the use of food wastes for the separation of organic molecules via PV technology [46]. They acquired characteristic solutes, including S-methyl thio-butyrate, dimethyl trisulfide, and dimethyl disulfide, from cauliflower blanching residues. These sulfur-based components were extracted using PEBA and PDMS membranes, in which they were highly selective for methyl thio-butyrate showing β factors of 1,200 and 307, respectively. The main lack of the membranes was related to their low productivities in terms of permeation.

288

Roberto Castro-Muñoz, Grzegorz Boczkaj

Essences were successfully separated from the oil extract of bergamot peels [55]. To cope with the complex extraction from this waste, Figoli and coworkers applied an enzyme treatment to preliminary extract bergapten, linalool, linalyl acetate, and limonene. At this point, the properties of PDMS membranes were found adequate to recover the aromas [61]; the study once again confirmed that temperature tends to improve the transport of organic components and hence obtain higher β factors. Martínez et al. [69] introduced the pervaporative separation of various categories of chemicals from brown crab boiling juices. Several alcohols, aldehydes, esters, ketones, furans, hydrocarbons, naphthalene derivates, sulfur compounds, and terpenes were identified and quantified by the authors. The results denoted that Pervap 4060 membrane efficiently separated specific solutes, including 1-(3H)-isobenzofuranone, cis-geranyl acetone, 2,5-dibutylfuran, 4-methyl-2-pentanone, 2,7-dimethylnaphthalene, and 4-methylthiazole (see Table 9.2). Very recently, fruit juice hydrolates were exploited by Dawiec-Liśniewska et al. [88] as a source of aromatic compounds. The aromas are generally present in such byproducts around 1wt.% of the total extract. Based on this, the diluted organics are frequently desired to carry out PV process. Dawiec-Liśniewska et al. [88] concentrated diverse aromas from plum, apple, blackcurrant, and cherry fruit derivates employing a laboratory and semi-technical scale PV setup [88, 89]. To sum up, the authors identified and quantified more than 30 different molecules in the blackcurrant hydrolates, and around 20 and 14 types of molecules were analyzed in apple and cherry hydrolates, respectively. Using a hydrophobic Pervap membrane, impressive β factors for several compounds were estimated of about 5800, 3678, 8602, and 1131 for pentan-1-ol, hexanal, butyl acetate, and heptan-1-ol, respectively. As expected, the highly selective properties of the membranes commonly bring low permeation properties, in this case, the membrane had a flux of 0.180 kg m−2 h−1, and it could be raised (ca. 0.450 kg m−2 h−1) when temperature increased. When the target deals with the enrichment of commercial products, a good alternative can be the extraction of aromas from particular processed food systems. Beer, wine, and cider have been some of the explored at separating specific aromas [65, 90, 91], however, the PV application has been also extended at producing novel market products attending specific needs of the costumers, for example, the production of nonalcoholic products. The following section compiles some case studies addressing such scope.

9.3 Pervaporation in the production of nonalcoholic drinks According to recent reports of the World Health Organization (WHO) [92], consumption of typical alcoholic beverages has tremendously raised in society. A current

Chapter 9 Pervaporation in food processing

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report notifies that the global consumption of alcoholic beverages is calculated to about 54.2 billion liters per year [93], in which beer and wine are found as the most consumed products [94]. Since it has been argued that high consumption of alcoholic beverages contributes to specific diseases, including pancreatitis, hepatitis, fatty degradation of liver, cirrhosis, peptic ulcers, allergenic induction, among others [95–97], there is a current trend in attending consumers’ necessity at producing products with similar physicochemical properties but alcohol-free. To date, it has been demonstrated that the best option for manufacturing such nonalcoholic beverages with the postfermentation removal of ethanol from the commercial products. In this way, PV has been devoted at selectively removing the ethanol; for instance, Catarino and Mendes [66] carried out the manufacture of low-alcohol content beer utilizing a hybrid industrial plant. Figure 9.3 illustrates the developed process implementing PV; this system comprised assisting distillation units with PV.

Figure 9.3: PV assisting the production of nonalcoholic beer. Adapted from [98].

In this work, the authors extracted the aromas from conventional beer using a PVPOMS membrane and subsequently blended into the dealcoholized beer. The industrial protocol led to manufacturing an alcohol-free beer presenting less than 0.5 vol% ethanol, meeting an acceptable flavor profile [66]. Similarly, PV was eventually utilized by Catarino en Mendes [90] for the separation of the aromatic components from wine. Here, the aroma extraction has been referred to meet the organoleptic attributes of the dealcoholized wine.

290

Roberto Castro-Muñoz, Grzegorz Boczkaj

More recently, PV acted as a fundamental unit operation in processing fullflavored low alcohol white wines [74]. PV was able to separate targeted molecules, for example, benzaldehyde, 1-hexanol, isoamylalcohol, hexanal, benzylalcohol, 2phenylethanol, from the grape must, and later embed them intentionally in the fermentation stage. The blending step helped to produce nonalcoholic wines with featured sensorial properties. Commercial beers, such as special beer (presenting 5.5% ABV) and reserve beer (presenting 6.5% ABV) were subjected to pervaporative processing to acquire aromas and flavor ingredients (isobutyl alcohol, ethyl acetate, and isoamyl acetate). Here, such organics were then blended in two different beers, such as low-alcohol beer (presenting