Studies on preparation of the polypeptide extracts from Porphyra haitanensis by composite protease method and ACE inhibitory activity

The content and extraction rate of protein,ACE inhibitory activity,sensory evaluation index and total plate count of extracts from Porphyra haitanensis treated by means of smash,grinding,protease hydrolysis,removing fishy and sterilization were investigated.It was found that the content and extraction rate of protein of laver extracts treated by means of smash,grinding and protease hydrolysis were increased observably and ACE inhibitory activity was also improved. It had great different effects on hydrolysis with various proteases. The results showed that extraction rate of protein reached 85.22% and ACE inhibitory activity was 93.51% using trypsin combined with alcalase,which was better than that with other protease. Besides,it had good removing fishy effects on extracts using 1.5%β-cyclodextrin.What's more,it remains good ACE inhibitory activity of extracts treated by sterilization.