Bioactive peptides with ACE-I and antioxidant activity produced from milk proteolysis

In this study, milk was hydrolyzed using protease (Asperigillus oryzae), trypsin, pepsin, or papain at concentrations of 0.001, 0.005, or 0.01 g/100 g milk for 30 or 60 min to produce angiotensin-converting enzyme inhibitory and antioxidant peptides. Results showed that the proteolysis, antioxidant, and ACE-I activity gradually increased with the increase in the enzyme concentration and hydrolysis time. The protease-treated milk had the highest proteolytic and ACE-I activity, while the papain-treated milk had the lowest. The papain-treated milk exhibited the greatest Fe2+ chelating activity. The use of trypsin at concentration of 0.001 g/100 g milk for 60 min produced ACE-I and antioxidant activity without changes in the technological properties of milk.