Abstract: In order to improve the ACE inhibitory rate of hydrolyzed soybean meal, alkaline protease was used in combination with neutral protease, compound protease, trypsin or flavorzyme for stepwise hydrolysis of soybean meal. The results showed that the highest hydrolysis degree, 46.83%, was achieved when soybean meal was sequentially hydrolyzed with alkaline protease followed by trypsin. Further investigations were carried out to optimize the hydrolysis process using response surface analysis. The optimal hydrolysis process was sequential hydrolysis with neutral protease for 2 h at a dose of 5100 U/g followed by trypsin at a dose of 950 U/g for another 2 h. The ACE inhibitory rate of final hydrolysis products was up to 72.21%.

Key words: multienzymctic hydrolysis, ACE inhibitory peptides, Box-Behnken experimental design