Preparation And Functional Analysis Of Bioactive Peptides Derived From Viscera Of Sea Cucumber

Sea cucumber is an ancient marine with rich protein content and low content of cholesterol and fat,having high nutritional and medicinal value.During processing of sea cucumber,quite amount of internal organs was produced.Studies have shown that the sea cucumber visceral is rich in protein,mucopoly saccharide,saponins and other active substances.In the present study,visceral of sea cucumber were used as raw material to prepare the bioactive peptides,and the antihypertensive effect was verified by animal experiments.Firstly,the basic components of sea cucumber visceral were measured.The content of protein was 64.06%and crude fat was 8.77%of the dry base.Amino acid composition analysis revealed that there are 17 kinds of amino acids,and the highest content is Aspartic acid and the essential amino acids accounted for 38.30%.Afterpre-treatment,Tricine-SDS-PAGEelectrophoresisanalysisand angiotensin-converting enzyme?ACE?inhibition rate as the assessment indicators,the sea cucumber visceral was hydrolyzed by neutral protease,alkaline protease,flavor protease and complex protease,after comparison,alkaline protease was selected as the optimal hydrolytic enzyme.By single factor and response surface experiments to explore with enzyme amount,temperature,time and material liquid ratio on the product of ACE inhibition rate,the results showed that the optimum process condition is enzyme dosage of 1.90%,at pH 8.3 and temperature of 55?with duration of 73 min.At this time,the ACE inhibition rate of enzyme solution was 91.32%.Using ultrafiltration membrane to decolor the hydrolyzed solution,the decolorization rate was higher than 90%,the treated solution almost revealed no odor.Spray drying was subsequently performed to get sea cucumber visceral bioactive peptide powder.The molecular weight of the visceral peptides was analyzed by high performance gel filtration chromatography.89.39%of the components were found to be less than 1000 Da.The L*value of the determination of sea cucumber visceral peptide was 87.31,with a high brightness and a pale yellow.Half scavenging effect(IC₅₀)of the ACE inhibition activity,DPPH·and Fe²⁺chelating capacity were 1.7,3.8 and 1.6 mg/m L respectively,when reduction force was 1,the concentration of sea cucumber visceral peptide was 3.6 mg/mL.Sea cucumber viscera peptides simulated gastric intestinal solution and have good stability after digestion.When the pH value of 5,the sea cucumber visceral peptide solubility of the worst,the solubility is best at 70?.A single medication at different doses of sea cucumber viscera peptide?100 mg/kg and 300mg/kg?,captopril?10 mg/kg?were intragastric administered to spontaneously hypertensive rats?SHRs?,and the changes of blood pressure in each group were observed.Comparing with the control group,the study shows that low dose group and high dose group of the blood pressure after treatment of 8 h were reduced by 36 mmHg and 49 mmHg;the blood pressure in positive control group which was given Captopril?10 mg/kg?decreased by 60 mmHg in 8 h.But after 24h,the blood pressure returned to the original blood pressure.The results showed that the peptide had a certain antihypertensive effect,and with the increase of the dose of sea cucumber visceral peptide,the blood pressure of SHRs decreased gradually.The preparation process of the sea cucumber visceral peptide was amplified,the yield of peptide powder was 48.42%.The IC₅₀ value of the ACE inhibition rate and DPPH·clearance rate was 2.6 mg/mL and 4.7 mg/m L respectively.Comparing with the small test,the activities both decreased.This study provides a reference for the industrial preparation of sea cucumber visceral peptides.