Abstract: Defatted pupa protein was prepared in our laboratory and used further to prepare ACE-inhibitory peptide by enzymatic hydrolysis. The best protease for preparing ACE-inhibitory peptide from pupa protein was chosen out of neutral protease, alcalase, papain, protamex, flavourzyme and trypsin. The hydrolysis process was optimized using response surface methodology. Neutral protease was found to be the best among all investigated proteases. The optimal hydrolysis conditions were determined as follows: substrate concentration of 11.88:100, hydrolysis temperature of 50.22 ℃, hydrolysis pH of 9.46, and enzyme concentration of 7.03%, hydrolysis time of 4 h. Under these conditions, pupa protein hydrolysate with an ACE-inhibitory rate of 41.98% was obtained.

Key words: pupa protein, ACE-inhibitory peptide, enzymatic hydrolysis, process conditions