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Overview
Whey is the residual liquid substance that is obtained by separating the coagulum from milk during cheesemaking. There are important components contained in whey, the most valued of which are the proteins which are highly regarded for their nutritional properties. The major whey proteins are Α-lactalbumin and Β-lactoglobulin. These globular proteins offer the most diverse functional benefits and have the greatest potential when used in further processed foods.
Whey protein concentrates (WPC) are products derived from whey from which the water, minerals and lactose have been removed. The process of protein concentration calls for the use of various separation techniques such as diafiltration, ultrafiltration, electrodialysis and ion-exchange technologies. WPC can be used in fluid, concentrate, or dry product form.
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Composition
WPC is a white to light cream-colored product with a bland, clean flavour. It is obtained by removing sufficient nonprotein constituents from whey so that the finished dry product contains no less than 25percent protein. In food systems, milk proteins contribute significantly to the nutritional benefits of the finished product. The compositions of some typical WPC powders are adjusted accordingly to the desired functionalities.
Caption text Typical composition of some WPC powders %WPC 35 50 65 80 Moisture 4.6% 4.3% 4.2% 4.0% Crude protein 36.2% 52.1% 63.0% 81.0% True protein 29.7% 40.9% 59.4% 75.0% Lactose 46.5% 30.9% 21.1% 3.5% Fat 2.1% 3.7% 5.6% 7.2% Ash 7.8% 6.4% 3.9% 3.1% Lactic acid 2.8% 2.6% 2.2% 1.2% WPC powders should be exempt of Salmonella, Listeria, coagulase-positive Staphylococcus and show a maximum Standard Plate Count of 50,000 colony-forming units/gram (CFU/g) and less than 10 Coliform CFU/g.
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Various uses
The use of many industrial whey products as ingredients in various foods is based not only on the nutritional qualities but also on the desirable functionality of some of these products.
WPC of 35percent protein is commonly used as a replacement for skimmed milk, as well as a stabilizer and fat mimetic in yogurt, bakery mixes, dietetic foods, infant foods, and confections. Its water-binding properties, fat-like mouthfeel, and gelation properties are of particular benefit when used in these further processed products.
WPC of 50, 65 or 80percent protein are especially suited for use in nutritional drinks, soups, bakery products, meat, dietetic foods, low-fat products and protein-fortified beverages. They are especially noted for their ability to completely dissolve in a wide range of pH conditions.
Defatted WPC powder containing 80 - 85percent protein is an excellent alternate ingredient to use in certain applications more notably as an economical egg-white replacer in whipped products such as meringues, modern ice-cream and toppings.
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Functional properties
Whey protein concentrates have many functional properties, most of which are associated with the whey proteins. Some of the basic functionalities that WPC can provide are water binding, whipping/foaming, emulsification, high solubility, gelation, viscosity development and browning. Generally, WPC with higher protein content have improved functionality over those with lower protein content.
Caption text Functional property Waterbinding/hydration Mode of action Proteins can help reduce formula costs as the proteins hold additional water Food system Meats, beverages, breads, cakes, sausages Caption text Functional property Gelation/viscosity Mode of action Protein-protein interactions produce matrix formations and settings Food system Salad dressings, soups, setting cheeses, baked goods, gravies, meats Caption text Functional property Emulsification Mode of action Proteins stabilize fat emulsions Food system Sausages, soups, cakes, salad dressings, infant foods Caption text Functional property Foaming/whipping Mode of action Proteins form stable film. Foaming properties are best when the whey proteins undenatured, not competing with other surfactants at the air/water interface Food system Whipped toppings, chiffon cakes, desserts Caption text Functional property Browning/flavour/aroma Mode of action Proteins contribute to browning by reacting with lactose and other reducing sugars present in a formulation, providing colour to heated products. WPC is bland tasting and contribute no foreign or off-flavours when used as an ingredient Food system Confections, meats in microwave, sauces, breads, low-fat baked goods, soups, dairy products For more information on concentrated and dried dairy products, please visit the University of Guelph's Dairy Science and Technology Web site.
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