Study on Composition and Antioxidant Properties of Sea Cucumber Peptides Prepared by Internal and External Enzymes

Abstract

In order to compare the composition and antioxidant properties of sea cucumber peptides prepared by different methods, sea cucumber peptides were prepared by endogenous enzyme (sea cucumber autolysis) and compared with those prepared by exogenous enzyme (neutral protease, alkaline protease and trypsin). The results showed that the degree of hydrolysis of sea cucumber crude peptide prepared by autolysis method was autolysis 8 h method>autolysis 4 h method>autolysis 2 h method, and the degree of hydrolysis of sea cucumber crude peptide prepared by exogenous enzyme was trypsin method>alkaline protease method>neutral protease method. More than 94% of sea cucumber peptides produced by autolysis for 2, 4 and 8 h were less than 314 Da. The molecular weight of sea cucumber peptides prepared by enzymatic hydrolysis was mainly distributed in 1~8.5 kDa； With the increase of autolysis time, the types of amino acids of sea cucumber peptides prepared by autolysis gradually increased, and the content of flavor amino acids was higher at 8 h. The sea cucumber peptides prepared by autolysis for 2, 4 and 8 h had better hydroxyl radical scavenging ability, DPPH radical scavenging ability and Fe3+ reducing ability than those prepared by enzymatic hydrolysis. At the concentration of 10 mg/mL, the hydroxyl radical scavenging rate of autolysis for 8 h was 93.4%, DPPH radical scavenging rate was 85.8% and Fe3+ reducing force was 0.740. In conclusion, sea cucumber peptides prepared by autolysis method had their own unique advantages. This study can provide theoretical support for the preparation of sea cucumber peptides.

Keywords

• sea cucumber
• enzymatic hydrolysis
• autolysis
• hydrolysis degree
• antioxidant