Other milk proteins are present in the whey serum and
whey proteins are defined as soluble proteins in the whey
after precipitation of caseins at pH 4.6 and at 20°C. (De Wit,
1981). Serum proteins include a first protein fraction
(80%) consisted of β-lactoglobulin (β-LG), β-lactalbumin (-
LA Da), bovine serum albumin (BSA) and immunoglobulin.
A second non-protein fraction (20%) is composed of
proteose, peptone and nitrogen compounds (Filio, 2006).