Study On Separation,Purification And Funtion Of Antioxidative Peptides From Barley Pest (Zophobs Morio L.)

Insect food is Treasury of human Functional Foods. The Zophobs morio L. is rich of proteins,and enzymatic hydrolysis of protein to prepare bioactive peptides have been paid more and more attention and studied.This paper attemped to make antioxidative peptide from Zophobs morio L. protein by protease enzyme,and its biological activities were studied. Exploitation of new antioxidative peptide and making full use of insect functional materials are of both theoretical and practical value.The main results were as follows:(1) Based on single factor test, the response surface was used to find out best conditions, and it was found that the optimum conditions were: time 120min, ratio of protease energy1︰1, substrate concentration 5%, dosage of protease 16mg/g,pH 8.64,and temperature 48.51℃.Under these conditions,DH was 12.96%,YASP was 78.39%.(2)Hydrolysate was separated using a Sephadex G-25 and Sephadex G-15 gel filtration chromatography column and fractionated into four portions.The antioxidative activity of these four portions could be described as:Ⅱ>Ⅲ>Ⅰ>Ⅳ,fractionⅡwas found to possess a strong antioxidative activity. FractionⅡwas separated using strong basidity anion exchage resin into two ingredient,ingredient Ia showed stronger activity than IIa,copmonent Ia was separated using strong-acidion-exchange resin into two component,component Ib exhibited strong scavenging activity to O-2·and·OH,with the scavenging rate reaching 72.89% and 89.43% respectively.(3)The amino acid composition analysis indicated that there were 19 amino acids in Zophobs morio L. ,and there were 8 kind of essential amino acids, the content of essential amino acids was 39.28%.8 kind of amino acids were found after Ib was purified. The content of these amino acids could be described as:Glu>Leu>Ala>Val>Gly>Pro>Asp>Ile. Antioxidant peptide was rich in Leu,Glu,Val,Ala.Compared with Zophobs morio L hydrolyzate,the concentration of each amino acid was increased,so these amino acids may play an important role in Zophobs morio L hydrolyzate.(4)The required concentration for Zophobs morio L hydrolyzate to remove O-2·,·OH,and DPPH·at IC50 level respectively is 13.76mg/mL,19.39 mg/mL,5.2579 mg/mL.While the required concentration for purified-polypeptide to remove O-2·,·OH,and DPPH·at IC50 level respectively is 0.4748mg/mL,0.693mg/mL,0.0496 mg/mL The ability of purified- polypeptide in O-2·,·OH,and DPPH·removing was respectively increased about 29 times,28 times,106 times.Both Zophobs morio L hydrolyzate and purified-polypeptide has some reducing power,and appeared good linear relationship.Within test range,reducing power increased with concentration,both the ability of radical removing and reducing power of purified-polypeptide were better than Vc.