SCREENING OF PROTEOLYTIC-ENZYMES TO ENHANCE FOAMING OF WHEY-PROTEIN ISOLATES

Whey protein isolate (WPI) was modified to enhance foaming characteristics by controlled hydrolysis using proteolytic enzymes. Alcalase, acid fungal protease, chymotrypsin, pepsin and trypsin were used to hydrolyze 5% rehydrated WPI. Degree of hydrolysis was estimated by freezing point depression and terminated at 2.5 to 3% by heating or pH adjustment. Controls were treated under similar conditions but without enzymes. Hydrolysates were separated into permeate and retentate by ultrafiltration and concentrated by reverse osmosis before freeze drying. Foam capacity, stability and surface tension of hydrolysates were measured. Permeate from Alcalase exhibited the best foaming characteristics, comparable to egg white.