Whey protein is a mixture of proteins isolated from whey, the liquid material created as a by-product of cheese production. The proteins consist of ?-lactalbumin, ?-lactoglobulin, serum albumin and immunoglobulins. Whey protein is commonly marketed as a dietary supplement, and various health claims have been attributed to it. An authoritative review published in 2010 concluded that the provided literature did not adequately support the proposed claims.
Production of whey
Whey is left over when milk is coagulated during the process of cheese production, and contains everything that is soluble from milk after the pH is dropped to 4.6 during the coagulation process. It is a 5% solution of lactose in water with lactalbumin and some lipid content. Processing can be done by simple drying, or the relative protein content can be increased by removing the lactose, lipids and other non-protein materials. For example, spray drying after membrane filtration separates the proteins from whey.
Commercially produced whey protein from cow's milk typically comes in four major forms:
Concentrates (WPC) have typically a low (but still significant) level of fat and cholesterol but, in general, compared to the other forms of whey protein, they are higher in carbohydrates in the form of lactose -- they are 29%-89% protein by weight.
Isolates (WPI) are processed to remove the fat and lactose -- they are 90%+ protein by weight. Like whey protein concentrates, whey protein isolates are mild to slightly milky in taste.
Hydrolysates (WPH) are whey proteins that are predigested and partially hydrolyzed for the purpose of easier metabolizing, but their cost is generally higher. Highly hydrolysed whey may be less allergenic than other forms of whey.
Native whey protein is extracted from skim milk, not a byproduct of cheese production, and produced as a concentrate and isolate.
There is evidence that whey protein is better absorbed than casein or soy protein.
Whey protein is commonly marketed as a dietary supplement, typically sold in powdered form for mixing into beverages. The products have varying proportions of the major forms above, and are promoted with various health claims. In 2010 a panel of the European Food Safety Authority (EFSA) examined proposed health claims made for whey protein: satiety, weight loss, reduced body fat, increased muscle, increased strength, increased endurance and faster recovery after exercising. The EFSA concluded that the provided literature did not adequately support the proposed claims.
^Morifuji, Masashi (2010). "Comparison of Different Sources and Degrees of Hydrolysis of Dietary Protein: Effect on Plasma Amino Acids, Dipeptides, and Insulin Responses in Human Subjects". J. Agric. Food Chem. 58 (15): 8788-8797.