Using high-pressure liquid chromatography we studied the distribution of molecular weights in whey-protein hydrolysates using the following commercially obtained proteases : Alcalasa 0.6 L and Protease 660 L, both bacterial in origin, and PEM 2500 S, of animal origin. In each of the systems, the range of molecular weights in the hydrolysate depended solely on the degree of hydrolysis (DH) achieved. For DH greater than or equal to 20, between 65% and 95% of the hydrolysate is made up of peptides with a molecular weight of less than 1,000 Da.