ACE-inhibitory Effect and Physicochemical Characteristics of Yogurt Beverage Fortified with Whey Protein Hydrolysates

This study investigated the ACE-inhibitory effect of yogurt beverage fortified with hydrolysates as well as the suitability of hydrolysates as a nutraceutical additive to yogurt beverage. Three whey protein hydrolysates hydrolyzed by alcalase, protamex, and trypsin were each added to yogurt beverage at concentrations of 1.25, 2.5, and 5 mg/mL. Yogurt beverage fortified with 2.5 mg/mL of hydrolysates had 61-69% ACE-inhibitory activity, whereas yogurt beverage fortified with 5 mg/ mL of hydrolysates showed 74% ACE-inhibitory activity. There were no significant differences in ACE-inhibitory activity between the alcalase or protamex hydrolysates during storage; however, trypsin hydrolysate exhibited significant differences. On the other hand, physicochemical characteristics such as pH (3.47-3.77), titratable acidity (0.81-0.84%), colority, viable cell count, and sensory qualities were not significantly different among the tested yogurt beverage samples during storage. These results showed that yogurt beverage fortified with whey protein hydrolysates maintained antihypertensive activity and underwent no unfavorable changes in physicochemical characteristics regardless of enzyme type.