In this experiment, different kinds of proteases were screened to prepare Angiotensin converting enzyme(ACE) inhibitory peptides from Sardine(Sardina melamosticta),and the process of preparing ACE-inhibitory peptides was optimized. The results showed that the combination of papain and Alcalase were the optimal enzymes for preparing ACE-inhibitory peptides from sardine. The optimal conditions of enzymatic hydrolysis were :30%(W/V) of sardine in water was hydrolyzed with 4000 U papain per gram of sardine at70...