Study On Preparation And Stability Of ACE Inhibitory Peptide From Common Carp Mussel

The angiotensin I-converting enzyme(ACE)inhibitory peptide,which can be released by gastrointestinal enzyme hydrolysis and regulate blood pres-sure through binding to ACE.Common carp(Cyprinus carpio)is a good resource of protein and favorite to Chinese.China has become the biggest producer of common carp.However,due to limitations in further processing technology,most of the common carps are traded in live,fresh,frozen,and dried forms.Therefore,common carp has a low commercial value and the waste of common carp protein is rather serious in China.In this thesis,we studied the extraction process of ACEIP from common carp mussel,purification of the angiotensin I-converting enzyme inhibitory peptides,identification of peptides and sequence analysis.The main results are as follows:1.This thesis use common carp mussel as the raw material,taking ACE inhibitory activity as index, after screening of alcalase,pepsin,trypsin,papain,the inhibition rate sort of liquid supernantants is alcalase>netural protease>trypsin>pepein?papain.The inhibition rate of alcalase is 86.0 ± 2.29%,higher than the other protease obviously.So Icalase was used to hydrolyze common carp mussel for production of ACEIP2.Taking ACE inhibitory activity as indexes,Response surface methodology design was used to optimize the hydrolysis conditions of common carp mussel protein with alcalase.Response surface methodolgy analyzed(RSM)optimal hydrolysis conditions of common carp mussel were:enzyme to substrate ratio4.32 U/mg,hydrolysis temperature 49?,hydrolysis time 4h.In these conditions,common carp mussel hydrolysates ACE inhibitory activity was 93.26%.3.3KDa ultrafiltration membrane was applied to isolated ACE inhibitory peptides.Fond that the function of molecular mass<3KDa(55.31±1.66%)had higher ACE inhibitory rate(36.03±2.55%).The function with low molecular mass had higher inhibition activity.4.Two step of Rp-HPLC were used to isolate Enzymatic hydrolysate for ACEIP.Finally function P-4 was purified and it's pureness was 95.77%.N-terminal sequence was used to identifited the peptides and sequence analysis,the Amino acid sequence of peptide is Tyr-Leu-Lys(YLK).5.Stability study of YLK against ACE had been studied,the result showed that YLK is belong to inhibitor-type peptides.The purified peptide solutions were subsequently incubated at different temperatures;different time;different pH,incubated with gastrointestinal proteases.We found that YLK still have high ACE inhibitory rate.The all stability studies showed that YLK had good processing adaptability.