Yada Proteins in Food Processing

1. Auflage 2004
ISBN: 978-1-85573-837-9
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 704 Seiten

Reihe: Woodhead Publishing Series in Food Science, Technology and Nutrition

Proteins are essential dietary components and have a significant effect on food quality. Edited by a leading expert in the field and with a distinguished international team of contributors Proteins in food processing reviews how proteins may be used to enhance the nutritional, textural and other qualities of food products.After two introductory chapters, the book discusses sources of proteins, examining the caseins, whey, muscle and soy proteins and proteins from oil-producing plants, cereals and seaweed. Part two illustrates the analysis and modification of proteins, with chapters on testing protein functionality, modelling protein behaviour, extracting and purifying proteins and reducing their allergenicity. A final group of chapters are devoted to the functional value of proteins and how they are used as additives in foods.Proteins in food processing is a comprehensive and authoritative reference for the food processing industry. - Reviews the wide range of protein sources available - Examines ways of modifying protein sources - Discusses the use of proteins to enhance the nutritional, textural and other qualities of food products

Autoren/Hrsg.

Yada, Rickey Y.

Inhaltsverzeichnis

1;Front Cover;1
2;Proteins in Food Processing;4
3;Copyright Page;5
4;Table of Contents;6
5;Contributor contact details;14
6;Chapter 1. Introduction;20
7;Chapter 2. Properties of proteins in food systems: an introduction;21
7.1;2.1 Introduction;21
7.2;2.2 Chemical and physical properties of food proteins;23
7.3;2.3 Factors affecting properties of proteins in food systems;31
7.4;2.4 Structure and function of proteins: classification and relationships;36
7.5;2.5 Future trends;39
7.6;2.6 Sources of further information and advice;41
7.7;2.7 References;41
8;Part I: Sources of proteins;46
8.1;Chapter 3. The caseins;48
8.1.1;3.1 Introduction: the caseins;48
8.1.2;3.2 Heterogeneity of the caseins;49
8.1.3;3.3 Molecular properties of the caseins;52
8.1.4;3.4 The caseins as food constituents and ingredients;55
8.1.5;3.5 The casein micelle: introduction;59
8.1.6;3.6 Properties and stabilisation mechanisms of casein micelles;62
8.1.7;3.7 Structure models of the casein micelle;65
8.1.8;3.8 Stability of casein micelles;70
8.1.9;3.9 Future trends;81
8.1.10;3.10 References;81
8.2;Chapter 4. Whey proteins;91
8.2.1;4.1 Introduction: whey proteins as food ingredients;91
8.2.2;4.2 Analytical methods for determining protein content;96
8.2.3;4.3 Structure of whey proteins;100
8.2.4;4.4 Improving functionality of whey proteins in foods: physical processes and enzymatic modification;104
8.2.5;4.5 Sources of further information and advice;112
8.2.6;4.6 References;113
8.3;Chapter 5. Muscle proteins;119
8.3.1;5.1 Introduction;119
8.3.2;5.2 Structure of muscle proteins and endogenous proteases;120
8.3.3;5.3 Muscle protein functionality;124
8.3.4;5.4 Prepared muscle proteins as functional ingredients;132
8.3.5;5.5 Future trends;135
8.3.6;5.6 Sources of further information and advice;136
8.3.7;5.7 References;137
8.4;Chapter 6. Soy proteins;142
8.4.1;6.1 Introduction;142
8.4.2;6.2 Soybean storage proteins: structure-function relationship of ß-conglycinin and glycinin;144
8.4.3;6.3 Soy protein as a food ingredient: physiochemical properties and physiological functions;148
8.4.4;6.4 Improving soy protein functionality;156
8.4.5;6.5 Conclusion;158
8.4.6;6.6 References;159
8.5;Chapter 7. Proteins from oil-producing plants;165
8.5.1;7.1 Introduction;165
8.5.2;7.2 Oilseed protein characteristics;165
8.5.3;7.3 Factors limiting protein utilization;169
8.5.4;7.4 Extraction and isolation of proteins;175
8.5.5;7.5 Functional properties of proteins;179
8.5.6;7.6 Improving functionality of oilseed protein;181
8.5.7;7.7 Future trends;185
8.5.8;7.8 References;186
8.6;Chapter 8. Cereal proteins;195
8.6.1;8.1 Introduction;195
8.6.2;8.2 Protein function in cereals;197
8.6.3;8.3 Classification of proteins;199
8.6.4;8.4 Gluten: formation, properties and modification;204
8.6.5;8.5 Processing and modification of cereal proteins in cereal products;207
8.6.6;8.6 Future trends;209
8.6.7;8.7 References;211
8.7;Chapter 9. Seaweed proteins;216
8.7.1;9.1 Introduction: seaweed and protein content of seaweed;216
8.7.2;9.2 Composition of seaweed proteins;219
8.7.3;9.3 Algal protein digestibility;221
8.7.4;9.4 Uses of algal proteins in food;226
8.7.5;9.5 Future trends;226
8.7.6;9.6 Sources of further information and advice;229
8.7.7;9.7 References;230
9;Part II: Analysing and modifying proteins;234
9.1;Chapter 10. Testing protein functionality;236
9.1.1;10.1 Introduction;236
9.1.2;10.2 Protein structure: sample characteristics and commercial proteins;238
9.1.3;10.3 Testing functionality;241
9.1.4;10.4 Model foods: foaming;243
9.1.5;10.5 Model foods: emulsification and gelation;249
9.1.6;10.6 Conclusions and future trends;254
9.1.7;10.7 Sources of further information and advice;254
9.1.8;10.8 Acknowledgement;254
9.1.9;10.9 References;254
9.2;Chapter 11. Modelling protein behaviour;264
9.2.1;11.1 Introduction;264
9.2.2;11.2 Computational methodology;265
9.2.3;11.3 Computer-aided sequence-based functional prediction;275
9.2.4;11.4 Future trends;283
9.2.5;11.5 Further information and advice;283
9.2.6;11.6 Conclusion;286
9.2.7;11.7 Acknowledgement;286
9.2.8;11.8 References;286
9.3;Chapter 12. Factors affecting enzyme activity in foods;289
9.3.1;12.1 Introduction;289
9.3.2;12.2 Types of enzymes and post-harvest food quality;289
9.3.3;12.3 Parameters affecting enzyme activity;294
9.3.4;12.4 Future trends;306
9.3.5;12.5 Sources of further information and advice;308
9.3.6;12.6 References;309
9.4;Chapter 13. Detecting proteins with allergenic potential;311
9.4.1;13.1 Introduction;311
9.4.2;13.2 Methods of analysing allergenic proteins;313
9.4.3;13.3 Methods of detecting food allergens;315
9.4.4;13.4 Developing new rapid tests: dip-sticks and biosensors;333
9.4.5;13.5 Future trends;335
9.4.6;13.6 Sources of further information and advice;336
9.4.7;13.7 References;336
9.5;Chapter 14. The extraction and purification of proteins: an introduction;342
9.5.1;14.1 Introduction;342
9.5.2;14.2 Factors affecting extraction;343
9.5.3;14.3 Extraction and fractionation methods;347
9.5.4;14.4 Purification techniques;351
9.5.5;14.5 Future trends;364
9.5.6;14.6 References;365
9.6;Chapter 15. The use of genetic engineering to modify protein functionality: molecular design of hen egg white lysozyme using genetic engineering;371
9.6.1;15.1 Introduction;371
9.6.2;15.2 Lysozyme-polysaccharide conjugates;372
9.6.3;15.3 Constructing polymannosyl lysozyme using genetic engineering;374
9.6.4;15.4 Improving functional properties of lysozymes;378
9.6.5;15.5 Acknowledgement;387
9.6.6;15.6 References;387
9.7;Chapter 16. Modifying seeds to produce proteins;389
9.7.1;16.1 Introduction;389
9.7.2;16.2 Methods of seed modification;391
9.7.3;16.3 Application and use of modified seeds for protein production;399
9.7.4;16.4 Future trends;405
9.7.5;16.5 Sources of further information and advice;406
9.7.6;16.6 References;406
9.8;Chapter 17. Processing approaches to reducing allergenicity in proteins;415
9.8.1;17.1 Introduction: food allergens;415
9.8.2;17.2 Protein allergens of animal origin;416
9.8.3;17.3 Protein allergens of plant origin;418
9.8.4;17.4 General properties of protein allergens: abundance, structural stability and epitopes;420
9.8.5;17.5 Factors affecting protein allergenicity in raw foods;422
9.8.6;17.6 Reducing protein allergenicity during food processing;424
9.8.7;17.7 Reducing protein allergenicity using enzymatic processing;428
9.8.8;17.8 Future trends: low allergen proteins;429
9.8.9;17.9 Acknowledgements;430
9.8.10;17.10 References;430
10;Part III: Applications;438
10.1;Chapter 18. Using proteins as additives in foods: an introduction;440
10.1.1;18.1 Introduction;440
10.1.2;18.2 Rheological properties of proteins;442
10.1.3;18.3 Surfactant properties of proteins;446
10.1.4;18.4 Protein-flavour relationships;449
10.1.5;18.5 Protein structure and techno-functionality;453
10.1.6;18.6 References;456
10.2;Chapter 19. Edible films and coatings from proteins;461
10.2.1;19.1 Introduction;461
10.2.2;19.2 Materials and methods used in protein film formation;462
10.2.3;19.3 Properties of protein film;465
10.2.4;19.4 Treatments used for modifying the functional properties of protein films and coatings;467
10.2.5;19.5 Commercial applications of protein films and coatings;470
10.2.6;19.6 Future trends;473
10.2.7;19.7 Sources of further information and advice;475
10.2.8;19.8 References;476
10.3;Chapter 20. Protein gels;487
10.3.1;20.1 Introduction;487
10.3.2;20.2 Food proteins and their gels;488
10.3.3;20.3 Mechanisms of protein gel formation;493
10.3.4;20.4 Mixed gels;496
10.3.5;20.5 Conclusion and future trends;498
10.3.6;20.6 Acknowledgement;499
10.3.7;20.7 References;499
10.4;Chapter 21. Proteomics: examining the effects of processing on food proteins;502
10.4.1;21.1 Introduction;502
10.4.2;21.2 Protein separation techniques;504
10.4.3;21.3 Using mass spectrometry to identify and characterize proteins;509
10.4.4;21.4 The impact of food processing on soy protein;522
10.4.5;21.5 Conclusion;530
10.4.6;21.6 Acknowledgements;530
10.4.7;21.7 References;531
10.5;Chapter 22. Texturized soy protein as an ingredient;536
10.5.1;22.1 Introduction: texturized vegetable protein;536
10.5.2;22.2 Texturized vegetable protein: raw material characteristics;538
10.5.3;22.3 Soy based raw materials used for extrusion texturization;540
10.5.4;22.4 Wheat and other raw materials used for extrusion texturization;548
10.5.5;22.5 Effect of additives on texturized vegetable protein;550
10.5.6;22.6 Types of texturized vegetable protein;553
10.5.7;22.7 Principles and methodology of extrusion technology;557
10.5.8;22.8 Processing texturized soy protein: extrusion vs. extrusion-expelling;562
10.5.9;22.9 Economic viability of an extrusion processing system for producing texturized soy chunks: an example;568
10.5.10;22.10 Uses of texturized soy protein;573
10.5.11;22.11 References;575
10.6;Chapter 23. Health-related functional value of dairy proteins and peptides;578
10.6.1;23.1 Introduction;578
10.6.2;23.2 Types of milk protein;578
10.6.3;23.3 General nutritional role of milk proteins;581
10.6.4;23.4 Milk protein-derived bioactive peptides;585
10.6.5;23.5 Mineral-binding properties of milk peptides;592
10.6.6;23.6 Hypotensive properties of milk proteins;598
10.6.7;23.7 Multifunctional properties of milk-derived peptides;609
10.6.8;23.8 Future trends;609
10.6.9;23.9 Acknowledgement;610
10.6.10;23.10 References;610
10.7;Chapter 24. The use of immobilized enzymes to improve functionality;626
10.7.1;24.1 Introduction;626
10.7.2;24.2 Modification of carbohydrates;628
10.7.3;24.3 Production of flavors and specialty products;632
10.7.4;24.4 Modification of lipids;634
10.7.5;24.5 Modification of proteins;637
10.7.6;24.6 Future trends;644
10.7.7;24.7 References;645
10.8;Chapter 25. Impact of proteins on food colour;650
10.8.1;25.1 Introduction: colour as a functional property of proteins;650
10.8.2;25.2 Role of proteins in food colour;658
10.8.3;25.3 Improving protein functionality in controlling colour;673
10.8.4;25.4 Methods of maintaining colour quality;675
10.8.5;25.5 Future trends;681
10.8.6;25.6 Sources of further information and advice;681
10.8.7;25.7 References;682
11;Index;688

Leseproben

3 The caseins
P.F. Fox; A.L. Kelly    University College, Cork, Ireland 3.1 Introduction: the caseins
There are two main types of proteins in milk, which can be separated based on their solubility at pH 4.6 at 20°C. Under these conditions, some of the proteins precipitate; these are called caseins. The proteins that remain soluble at pH 4.6 are known as serum or whey proteins. Approximately 80% of the total nitrogen in bovine, ovine, caprine and buffalo milk is casein; however, casein represents only ~40% of the protein in human milk. About 3% of the total nitrogen in bovine milk is soluble in 12% trichloroacetic acid (TCA) and is referred to as non-protein N (NPN); its principal constituent is urea. The fat globule membrane contains several specific proteins, including many enzymes, at trace levels; these represent ~1% of the total protein in milk. Probably because of their ready availability, the milk proteins have been studied since the very beginning of protein chemistry. The first research paper on milk proteins (curd) appears to have been published by J. Berzelius in 1814. The term ‘casein’ appears to have been used first in 1830 by H. Broconnet, i.e., before the term ‘protein’ was introduced in 1838 by G. J. Mulder, whose studies included work on milk proteins. Early researchers were very confused as to the nature of proteins; they believed that there were three types of protein: albumin (e.g., egg white), fibrin (muscle) and casein (milk curd), each of which occurred in both animals and plants (Johnson, 1868). The caseins were considered to be those plant or animal proteins that could be precipitated by acid or by calcium or magnesium salts. The preparation of casein from milk by isoelectric precipitation was improved and standardised by Hammarsten (1883); milk was diluted 1:5 with water and made to 0.1% acetic acid (which gave apH of ~4.6); isoelectric casein is still often referred to as casein nach Hammarsten. The preparation of isoelectric casein was further refined by van Slyke and Barker (1918). Isoelectric casein was considered initially to be homogeneous; the first evidence that it is heterogeneous was published by Osborne and Wakeman (1918). Further evidence of heterogeneity, based on fractionation with ethanol-HCl mixtures, was presented by Linderstrøm-Lang and Kodama (1925) and Linderstrøm-Lang (1925, 1929). However, heterogeneity was not generally accepted until the application of free boundary electrophoresis to the study of milk proteins by Mellander (1939), who showed that isoelectric casein consists of three proteins, a-, ß- and ?-caseins, representing 75, 22 and 3% of total casein, respectively. Heterogeneity was also demonstrated by analytical ultracentrifugation (Svedberg et al., 1930; Pedersen, 1936) but protein-protein association is now known to be mainly responsible for the heterogeneity observed on ultracentrifugation. The a-casein resolved by free boundary electrophoresis is, in fact, a mixture of three proteins: as1-, as2- and ?-caseins. Waugh and von Hippel (1956) resolved a-casein into calcium-sensitive (as-) and calcium-insensitive (?-) fractions. The as-casein fraction was resolved further into two distinct proteins, now known as as1- and as2-caseins, by Annan and Manson (1969). The very extensive literature on various aspects of milk proteins has been reviewed at regular intervals, including textbooks by McKenzie (1970, 1971), Fox (1982, 1989, 1992), Walstra and Jenness (1984), Wong (1988), Barth and Schlimme (1988), Cayot and Lorient (1998) and Fox and McSweeney (1998, 2003). All the principal milk proteins have been isolated and characterised thoroughly at the molecular and physico-chemical (functional) levels. However, the milk proteins are still an active and fertile subject for research: knowledge of the structure of the caseins is being refined, new biological functions are being identified and the genetic control of milk protein synthesis is being elucidated, creating the possibility of altering the protein profile of milk and exploiting the mammary gland to synthesise exogenous, possibly pharmaceutically-important, proteins. In this chapter, the heterogeneity, molecular and functional properties of the caseins, the structure and properties of the casein micelle, the role of caseins as food ingredients and bioactive peptides derived from the caseins will be discussed. 3.2 Heterogeneity of the caseins
The four proteins in bovine casein, as1-, as2-, ß- and ?-, represent approximately 38, 10, 36 and 12%, respectively, of whole casein. Each of the caseins exhibits microheterogeneity, for one or more reasons: • variation in the degree of phosphorylation • variation in the degree of glycosylation in the case of ?-casein • genetically controlled amino acid substitutions, leading to genetic polymorphism • formation of disulphide-linked polymers in the case of as2- and ?-caseins • proteolysis by indigenous proteinases. 3.2.1 Phosphorylation of the caseins
All of the caseins are phosphorylated: most molecules of as1-casein contain 8 PO4 residues but some contain 9; ß-casein usually contains 5 PO4 residues but some molecules contain 4; as2-casein contains 10, 11, 12 or 13 PO4 residues; most molecules of ?-casein contain only 1 PO4 residue but some contain 2 or perhaps 3. The phosphate groups of the caseins are esterified as monoesters of serine or, to a very minor extent, of threonine. The phosphate group for phosphorylation is provided by ATP and transfer is catalysed by casein kinases. A specific sequence, Ser.X.A (where X is any amino acid and A is an anionic residue, i.e., Glu, Asp or SerP), is required for phosphorylation. As a result of this requirement, not all Ser residues are phosphorylated; furthermore, although a few Ser residues in the sequence cited above are not phosphorylated, probably for steric reasons, no Ser residue without an adjacent anionic residue is phosphorylated. Most of the phosphoserine residues in the caseins occur in clusters. The phosphate groups per se are very important from a nutritional viewpoint but they also bind polyvalent cations strongly. In milk, the principal cation bound is calcium, with smaller amounts of other cations, including Zn; these cations are very important nutritionally. Binding of cations causes charge neutralisation and precipitation of as1-, as2- and ß-caseins. ?-Casein, which usually contains only 1 PO4 residue, binds cations weakly and is not precipitated by them; furthermore, it can stabilise up to ten times its weight of calcium-sensitive caseins through the formation of micelles, the significance of which will be discussed below. 3.2.2 Glycosylation of the caseins
?-Casein is the only glycosylated casein; it contains galactose, galactosamine and N-acetylneuraminic (sialic) acid, which occur either as trisaccharides or tetrasaccharides attached to theronine residues in the C-terminal region. ?-Casein may contain 0 to 4 tri- or tetra-saccharides and there are at least nine variants differing in carbohydrate content and type. The presence of oligosaccharides in the C-terminal region of ?-casein increases its hydrophilicity. 3.2.3 Genetic polymorphism of the caseins
All the caseins exhibit genetic polymorphism, which involves the substitution of 1 or 2 amino acids or, very rarely, the deletion of a sequence of amino acid residues, e.g., as1-CN A and as2-casein D (Ng-Kwai-Hang and Grosclaude, 2003). Polymorphism is determined by simple Mendelian genetics. To date, 32 genetic variants of the bovine caseins have been identified. However, since genetic polymorphism is normally detected by electrophoresis, only substitutions that cause a change in charge are detected. It is almost certain that there are numerous undetected (silent) substitutions involving uncharged residues; such variants can be detected by mass spectrometry. The presence of certain genetic variants in milk has a significant effect on some of its properties, e.g., protein content and profile, cheesemaking properties and heat stability. Goats may possess so-called null alleles, as a result of which a particular protein is absent from the milk; obviously, such an event has a major impact on the properties of milk. To date, null variants have not been detected in cattle. 3.2.4 Disulphide linking of caseins
as2- and ?-caseins contain two cysteine residues, which normally exist as intermolecular disulphide bonds; as2-casein usually exists as disulphide-linked dimers but up to at least ten...