Preparation Of Sea Cucumber Polypeptide By Hydrolysis And The Study Of Its Antioxidant Properties

The sea cucumber is rich in nutrient and contains a variety of trace elements that are beneficial to people.It has high nutritional value and commercial value, so many countries pay more and more attention to the deep research and the development of the sea cucumber. With the deep of the theoretical research, the radical is more and more widely known by people and the antioxidants has drawn wide attention. Sea cucumber polypeptide has strong antioxidant activity and therefore has great development potential.The experiment selected papain, neutral protease AS1398and composite trypsin to hydrolysis fresh sea cucumber to get polypeptide under the same conditions. We took a sample every30min and measured its activity of clearing the hydroxyl radical and the superoxide anionthe, all of which was to study the relationship between the antioxidant activity of the three enzymes and the hydrolysis time. The results showed that the sea cucumber peptides from papain had the highest points of scavenging hydroxyl radicals between120-150min and at the60min and the superoxide anion highest point is in120-150min; the sea cucumber peptides from neutral protease had the highest points of scavenging hydroxyl radicals at the60min and the150min and the superoxide anion highest point is at130min; the sea cucumber peptides from composite trypsin had the highest points of scavenging hydroxyl radicals at70min and180min. The sea cucumber peptide from papain had a higher activity of clearing superoxide anion,and the clearance rate was25.10%; the sea cucumber peptide from neutral protease AS1398had a higher activity of clearing hydroxyl radical,the rate is77.00%.Ultrafiltration membrane(10kDa and5kDa) was used to ultrafiltrate the sea cucumber peptides from composite trypsin, and some peptides that is less than5kDa was molecular sieve chromatographied using Sephadex G-25to get two kinds of sea cucumber peptides that have absorption at the280nm. By UV absorption method,, several components of the peptide concentration were measured respectively,and four components’activity of scavenge hydroxyl radicals and superoxide anion were measured at the same time, and then calculated the relative activity of each component. The results showed that the sea cucumber that the molecular weight is less than5kDa were the main distribution peptides to superoxide anion, and clearing the hydroxyl radical sea cucumber peptides were below5kDa component and Mr> lOkDa sea cucumber peptides.