Effects of Enzymatic Hydrolysis on the Foaming Properties of Whey Proteins

Changes in the foaming properties of whey proteins concentrate (WPC) subjected to enzymatic hydrolysis were studied. Activity and stability of the foam generated from the enzymatic hydrolysis of WPC with two proteases: Trypsin from porcine pancreas (analytical quality) and Alcalase 2.4 L FG (Alcalase) (commercial food grade) were analyzed. WPC solution at concentration 100 mg/mL in 50 mM phosphate buffer, pH 8,0 were hydrolyzed with Trypsin and Alcalase at the ratio of enzyme/substrate 1:100 and 1:250, respectively. The reactions were stopped by heating. The relationship between the concentrations of different species with hydrolysis time was studied by means of electrophoretic techniques and it was found that Alcalase hydrolyzed more efficiently than Trypsin. For Alcalase hydrolysates of WPC the degree of hydrolysis, for 60 minutes of treatment, was about 45% while for Trypsin hydrolysates, with the same treatment time, was around 7%. Foams were obtained by bubbling. We could observe little variation on the activity of the foams obtained with both enzymatic treatments for all times of hydrolysis. Foams obtained from Trypsin hydrolysates were more stable than the ones obtained from Alcalase hydrolysates. Although foams formed with WPC hydrolysates using Alcalase were less stable than their counterparts obtained with Trypsin, faster hydrolysis, availability and lower cost make Alcalase a very good choice when you want to work with additives obtained by hydrolysis of WPC having improved foam stability.