Bioactive Peptides Prepared From Sea Cucumber Oven And Oyster

In the present study,sea cucumber ovum and oyster were hydrolyzed by using trypsin,papain,neutrase and alcalase to produce bioactive peptides.The antioxidative activities of these peptides were investigated in DPPH assay,Fenton assay,and reducing power assay.The preparation processing for the bioactive peptides was optimized by single factor experiment and response surface method.In order to examine the relationship between the molecular weight distribution and the activity of peptides,the hydrolysates were fractionated by using a series of ultrafiltration membranes(molecular weight cut-offs of 10,5,3 and 1 kDa)and five fractions with different molecular weight ranges were obtained from each enzyme-derived hydrolysates:<10 kDa,5-10 kDa,3-5 kDa,1-3 kDa and<1 kDa.The resulting peptide fractions were investigated for their antioxidant activities and the results indicated that the peptides below 3 kDa showed the strongest overall antioxidant activity.In order to examine the relationship between the amino acid composition and the activity,the 1-3 kDa peptide fraction was separated by using a semi-preparation high-performance liquid chromatography equipped with an anion ion-exchange column.The effluent fractions were assayed for their DPPH scavenging capacity and the results indicated that the alkaline peptides having short retention time possessed better radical scavenging capacity.The optimum enzymes were selected according to the antioxidation activities,degree of hydrolysis and yield of peptides.Take hydrolysis degree as target,the optimum enzymolysis conditions for the optimum enzymes were ascertained by using single factor experiment and response surface method.The optimum conditions for the production of peptides are listed as below:?Sea Cucumber Ovum:the hydrolytic temperature is 52.06?;the reactive pH is 5.5;the sample-to-solvent ratio is 8.41%;the additive amount of papain is 2500 U/g substrate;the hydrolytic time is 4 h.Under this condition,the theoretic hydrolysis degree,the true hydrolysis degree is 20.27%,20.51%respectively;?Oyster:the hydrolytic temperature is 48.96?;the reactive pH is 7.08;the sample-to-solvent ratio is 7.92%;additive amount of neutrase is 2500 U/g substrate;the hydrolytic time is 4 h.Under this condition,the theoretic hydrolysis degree,the true hydrolysis degree is 39.29%,39.53%respectively.