| Angiotensin-I converting enzyme (ACE) inhibitory peptides were prepared from pumpkin seed protein using ball-milling assisted enzymolysis method. With ACE inhibition rate and degree of hydrolysis as indicators, the protease was screened and the effects of ball-milling time, enzymolysis time, substrate mass concentration, pH and enzymolysis temperature were studied by single factor experiment. Then the ball-milling assisted enzymolysis conditions were optimized by response surface methodology with ACE inhibition rate as indicator. The results showed that the enzymolysis efficiency of pumpkin seed protein could be improved significantly by ball-milling pretreatment. The optimal ball- milling assisted enzymolysis conditions were obtained as follows: using alkaline protease, ball-milling time 6 min, enzymolysis time 10 h, substrate mass concentration 0.08 g/mL, pH 8.5 and enzymolysis temperature 55 ℃. Under these conditions, the ACE inhibition rate of ACE inhibitory peptides could reach (86.65±0.55)%. |
