Whey Protein Fractionation Overview and Membrane Operations

Milk is defined as the secretion of the mammary glands of mammals with the primary function to satisfy nutritional requirements of neonates. Milk of some animals, especially cows, buffaloes, goats, and sheep, is used for human consumption, either as such or in the form of a range of dairy products. Milk may also be defined as a true solution of lactose and minerals, colloidal dispersion of milk proteins, and emulsion of milk fat. Fat globules are dispersed into the serum phase of milk. Milk proteins are grouped into two main classes – caseins and whey proteins, which are obtained by acid or rennet-induced coagulation of casein and their removal from the serum. The milk serum, basically devoid of caseins, is commonly termed the whey. Depending on a source (Table 1), composition of milk and thus the whey varies.

Table 1 Composition of milk of main mammalian species (Kailasapathy 2008)