Whey Protein Denaturation in Concentrated Skimmilks

Abstract

The relative denaturation susceptibility of whey proteins in skimmilk and its concentrates was studied by heating milks of 9 to 44% total solids for 5, 10, 15 and 20 rain at 75 and 80 C. Results indicated that solids are more critical than temperature variations. Denaturation at 80 C for 20 rain decreased from 80 to 59 to 39% as the total solids increased from 9 to 28 to 44%. An equation relating percentage denaturation with time, temperature and solids was derived from the ex-perimentaI data. Although denaturation susceptibility of whey proteins in skimmilk, expressed as percentage denatured, is reduced by concentration, the actual rate of reaction is normal first order for heating in excess of five minutes.