Factors Affecting the Denaturation and Aggregation of Whey Proteins in Heated Whey Protein Concentrate Mixtures

Whey protein concentrate (65% protein) mixtures, alone or in the presence of NDM, were heated at 66 and 71C for up to 120 min to yield 16, 25, and 35% TS to simulate the formulation of a nutritional product. Addition of low heat NDM to a whey protein concentrate mixture to yield 35% TS resulted in 6 and 20% denaturation after 120 min and 27 and 83% in the whey protein concentrate mixture (16% TS) at 66 and 71T, respectively. The effects of Ca and pH on whey protein denaturation and aggregation (66C) were also studied. A whey protein concentrate mixture (16% TS) dialyzed against simulated milk ultrafiltrate containing 0 to 9 m M Ca and heated (66C); the mixture was progressively more denatured and formed less soluble aggregate and more insoluble precipitate as the Ca increased. When the whey protein concentrate mixture (16% TS) was heated (66'C) at increasing pH (5.8 to 7.0), whey protein denaturation and insoluble precipitate increased. The a-LA denatured more extensively than P-LG at 66 and 71C.