Animal-derived Casein Whey proteins Gelatin Egg proteins Plant-derived Soy protein Wheat protein

Transcription

1 Table 14.1 Principal non-catalytic proteins that find bulk industrial application. Although most are used as, or added to, human food/animal feed, some also have non-food applications in the pharmaceutical and cosmetics sectors for example. Animal-derived Casein Whey proteins Gelatin Egg proteins Plant-derived Soy protein Wheat protein

2 Table 14.2 Functional properties exhibited by some proteins which renders attractive their addition to selected foods. Functional property Protein (example) Food (example) Viscosity Gelatin Soups, gravies, desserts Gelation Cohesion Milk and egg proteins Whey and egg proteins Confectionery, some meat products Bakery products, pasta, sausages Elasticity Cereal products Bakery products, meats Fat/flavour binding Emulsification Foaming Milk, egg, cereal proteins Milk and egg proteins Milk and egg proteins Confectionery, bakery products Sausages, soups, cakes Cakes, ice creams, whipped toppings

3 Table 14.3 Average composition (% w/v) of the milk of humans and various agriculturally important species. Species Lactose Fat Protein Total solids Human Cow Sheep Goat

4 Table 14.4 The major dairy-based products, how they are produced and their uses. Process Primary product Further products Centrifugal separation Cream Butter, butteroil, ghee Creams: various fat content (HTST pasteurized or UHT sterilized, coffee creams, whipping creams, dessert creams), cream cheeses Skim milk Powders, casein, cheese, protein concentrates Concentration: thermal evaporation or ultrafiltration Concentration and drying In-container or UHT -sterilized concentrated milks Sweetened condensed milk Whole milk powders; infant formulae; dietary products Enzymatic coagulation Cheese 1000 varieties; further products, e.g. processed cheese, cheese sauces, cheese dips, cheese analogues Rennet casein Whey Whey powders, demineralized whey powders, whey protein concentrates, whey protein isolates, individual whey proteins, whey protein hydrolysates, neutraceuticals. Lactose and lactose derivatives Acid coagulation Cheese Fresh cheeses and cheese-based products Acid casein Functional applications, e.g. coffee creamers, meat extenders; nutritional applications Whey Whey powders, demineralized whey powders, whey protein concentrates, whey protein isolates, individual whey proteins, whey protein hydrolysates, neutraceuticals Fermentation Various fermented milk products, e.g. yoghurt, buttermilk, acidophilus milk, bioyoghurt Freezing Ice-cream (numerous types and fomulations) Miscellaneous Chocolate products Source: Fox, P. and McSweeney, P. (1997) Dairy Chemistry and Biochemistry, p. 17. Blackie Academic and Professional, London. Reproduced with kind permission from Springer Science+Business Media B.V.

5 Table 14.5 Methods by which micellar caseins may be extracted from milk on a laboratory scale. Method Details Centrifugation Micelles can be sedimented by centrifugation at 100,000 g for 1 hour. Prior addition of CaCl 2 (0.2 mol/l) causes more extensive aggregation of micelles, allowing their recovery at lower centrifugal speeds Isoelectric precipitation Acidification of milk to ph 4.6 Salting out Addition of ammonium sulfate (to a concentration of 260 g/l) precipitates casein (and also some whey proteins) Ethanol precipitation Addition of ethanol to a final concentration of 40% selectively precipitates casein from solution Cryoprecipitation Cooling of milk to 10 C precipitates casein Ultrafiltration Ultrafiltration of whole milk will concentrate/retain both casein and whey proteins Treatment with chymosin Aggregrated casein micelles precipitate and are easily recovered from milk. κ-casein component is obviously modified Chromatographic purification Methods such as ion-exchange and gel filtration chromatography may be used to partially/fully separate caseins from other milk poteins

6 Table 14.6 Major applications of milk-derived proteins in the food industry. Bakery products Caseins/caseinates/co-precipitates Used in: bread, pastries/cookies, breakfast cereals, cake mixes, pastries, frozen cakes and pastries, pastry glaze Effect: nutritional, sensory, emulsifier, dough consistency, texture, volume/yield Whey proteins Used in: bread, cakes, muffins, croissants Effect: nutritional, emulsifier, egg replacer Dairy products Caseins/caseinates/co-precipitates Used in: imitation cheeses (vegetable oil, caseins/caseinates, salts and water) Effect: fat and water binding, texture enhancing, melting properties, stringiness and shredding properties Used in: coffee creamers (vegetable fat, carbohydrate, sodium caseinate, stabilizers and emulsifiers) Effect: emulsifier, whitener, gives body and texture, promotes resistance to feathering, sensory properties Used in: cultured milk products, e.g. yoghurt Effect: increase gel firmness, reduces syneresis Used in: milk beverages, imitation milk, liquid milk fortification, milk shakes Effect: nutritional, emulsifier, foaming properties Used in: high-fat powders, shortening, whipped toppings and butter-like spreads Effect: emulsifier, texture enhancing, sensory properties Whey proteins Used in: yoghurt, Quarg, Ricotta cheese Effect: yield, nutritional, consistency, curd cohesiveness Used in: cream cheeses, cream cheese spreads, sliceable/squeezable cheeses, cheese fillings and dips Effect: emulsifier, gelling, sensory properties Beverages Caseins/caseinates/co-precipitates Used in: drinking chocolate, fizzy drinks and fruit beverages Effect: stabilizer, whipping and foaming properties Used in: cream liqueurs, wine aperitifs Effect: emulsifier Used in: wine and beer industry Effect: fines removal, clarification, reduce colour and astringency Whey proteins Used in: soft drinks, fruit juices, powdered or frozen orange juices Effect: nutritional Used in: milk-based flavoured beverages Effect: viscosity, colloidal stability Dessert products Caseins/caseinates/co-precipitates Used in: ice-cream, frozen desserts Effect: whipping properties, body and texture Used in: mousses, instant puddings, whipped toppings Effect: whipping properties, film former, emulsifier, imparts body and flavour Whey proteins Used in: ice-cream, frozen juice bars, frozen dessert coatings Effect: skim-milk solids replacement, whipping properties, emulsifying, body/texture Confectionery Caseins/caseinates/co-precipitates Used in: toffee, caramel, fudges Effect: confers firm, resilient, chewy texture; water binding, emulsifier Used in: marshmallow and nougat Effect: foaming, high-temperature stability, improve flavour and brown colour Whey proteins Used in: aerated candy mixes, meringues, sponge cakes Effect: whipping properties, emulsifier

7 Table 14.6 (Continued) Pasta products Used in: macaroni, pasta and imitation pasta Effect: nutritional, texture, freeze-thaw stability, microwaveable Meat products Caseins/caseinates/co-precipitates Used in: comminuted meat products Effect: emulsifier, water binding, improves consistency, releases meat proteins for gel formation and water binding Whey proteins Used in: frankfurters, luncheon meats Effect: pre-emulsion, gelation Used in: injection brine for fortification of whole meat products Effect: gelation, yield Convenience foods Used in: gravy mixes, soup mixes, sauces, canned cream soups and sauces, dehydrated cream soups and sauces, salad dressings, microwaveable foods, low-lipid convenience foods Effect: whitening agents, dairy flavour, flavour enhancer, emulsifier, stabilizer, viscosity controller, freeze-thaw stability, egg yolk replacement, lipid replacement Textured products Used in: puffed snack foods, protein-enriched snack-type products, meat extenders Effect: structuring, texturing, nutritional Pharmaceutical and medical products Special dietary preparations Ill or convalescent patients Dieting patients/people Athletes Astronauts Infant foods Nutritional fortification Humanized infant formulae Low-lactose infant formulae Specific mineral balance infant foods Casein hydrolysates: used for infants suffering from diarrhoea, gastroenteritis, galactosaemia, malabsorption, phenylketonuria Whey protein hydrolysates used in hypoallergic formulae preparations Nutritional fortification Intraveneous feeds Patients suffering from metabolic disorders, intestinal disorders for postoperative patients Special food preparations Patients suffering from cancer, pancreatic disorders or anaemia Specific drug preparations β-caseinomorphins used in sleep or hunger regulation or insulin secretion Sulfonated glycopeptides used in treatment of gastric ulcers Miscellaneous products Toothpastes Cosmetics Wound treatment preparations Source: Fox, P. and McSweeney, P. (1997) Dairy Chemistry and Biochemistry. Blackie Academic and Professional, London. Reproduced with kind permission from Springer Science+Business Media B.V.

8 Table 14.7 Composition (%) of rennin-derived whey. Lactose 4.77 Protein 0.82 Fat 0.07 Lactic acid 0.15 Calcium 0.05 Potassium 0.13 Sodium 0.07 Phosphorus 0.06 Water 93.0

9 Table 14.8 Some physicochemical characteristics of the major (bovine) whey proteins. β-lactoglobulin α-lactalbumin Serum albumin IgG Concentration (g/l) Molecular mass (kda) ~150 No. of amino acid residues ~1360 No. of cysteine residues Isoelectric point (pi) Glycosylated? No No No Yes

10 Table 14.9 Amino acid composition (%) of gelatin. Glycine 23.0 Alanine 7.8 Valine 2.25 Leucine 2.9 Isoleucine 1.26 Cysteine 0.09 Methionine 0.9 Phenylalanine 2.0 Proline 16.2 Hydroxyproline 12.7 Serine 0.36 Threonine 1.7 Tyrosine 0.45 Aspartate 6.0 Glutamate 10.2 Arginine 7.3 Lysine 3.7 Histidine 0.72

11 Table Major food and non-food applications of collagen-derived gelatin. Food applications Gelling agent Stabilizer Thickener Emulsifier Foaming agent Pharmaceutical/medical Gelatin-based capsules Thickening agents for pastes Gelling agent for suppositories Gelatin-based surgical sponges Other uses Glue manufacture Binder in match heads Sizing agent for paper/textile manufacture Photographic films Manufacture of rubber substitutes

12 Table Major protein types found in egg white. Immunoglobulins are found in egg white and yolk. Refer to text for further details. Protein Per cent of egg white Molecular mass (kda) pi Ovalbumin (egg albumen) Ovotransferrin (conalbumin) Ovomucoid Lysozyme Ovomucin (α and β) (α), 400 (β) Immunoglobulins (various) <1.0 Vary Vary

13 Table The major globulin-based seed proteins found in soybean. 7S Globulins β-conglycinin, a kda glycoprotein γ-conglycinin, a 170 kda glycoprotein Basic 7S globulin, a 168 kda glycoprotein 11S Globulins Glycinin, a kda protein

14 Table Some sweet/taste-modifying proteins and their sources. Protein Source Molecular mass (kda) Sweetness (relative to sucrose on a weight basis) Thaumatin Fruit of Thaumotococcus daniellii Monellin Fruit of Dioscoreophyllum cumminsii Mabinlin Seeds of Capparis masaikai Pentadin Berries of Pentadiplandra brazzeana Miraculin Berries of Richadella dulcifica 28.0 Tasteless Curculin Fruits of Curculigo latifolia