Abstract:The enzymatic hydrolysis methods for preparing angiotensin I-converting enzyme（ACE）inhibitory peptides and antioxidant peptides were studied.Three proteases（alkaline protease，neutral protease，and Bacillus subtilis protease）were selected for enzymatic hydrolysis to prepare functional active peptides from mulberry leaves.The ACE inhibition activity was evaluated with ACE inhibition rate and degree of hydrolysis（DH）as the indicators.The antioxidant performance was evaluated based on the scavenging activity against DPPH free radicals and total antioxidant capacity（T-AOC）.The single factor method was employed to optimize the enzymatic hydrolysis conditions including enzymatic hydrolysis pH，substrate concentration，enzyme addition amount，enzymatic hydrolysis temperature，and enzymatic hydrolysis time.The results showed that the enzymatic hydrolysates of three proteases all exhibit ACE inhibitory activity，and the neutral protease hydrolysates had the best effect.The enzymatic hydrolysis conditions were optimized as substrate concentration of 20 g/L，enzyme addition of 7.5%，enzymatic hydrolysis at 55 ℃for 50 min，and pH 7.0.The hydrolysates obtained under these conditions showed the ACE inhibition rate of 81.23% and DH of 21.41%.Measure the antioxidant capacity of three enzymatic hydrolysis products under different protease optimization conditions，the neutral protease hydrolysates showed the highest DPPH free radical scavenging rate（80.702%）and total antioxidant capacity（4.717 mmol/g）.