Influence of chemical modification of whey protein conformation on hydrolysis with pepsin and trypsin

The whey protein conformation was modified by sulfitolysis. The modified wh ey protein was fractioned into the precipitate and soluble fractions by low ering pH. The modified whey proteins and the two protein fractions were hyd rolyzed with pepsin and trypsin. The modified whey proteins hydrolyzed more readily than intact proteins, and the formation of the peptides <2000 Da c orrelated with the rate of the hydrolysis of both proteins. The rate of the hydrolysis of the precipitate fraction was higher than that of the soluble fraction, while the rate of the intact protein was variably lower or highe r than that of the soluble fraction. Generally, the rate of the formation o f peptides <2000 Da correlated with that of the hydrolysis of both fraction s. The beta -lactoglobulin antigenicity of both fractions decreased markedl y during pepsin hydrolysis and approached zero in trypsin hydrolysis within 30 min. (C) 2001 Elsevier Science Ltd. All lights reserved.