Preparation,Antioxidant Activity And Mechanism Of Antioxidant Peptide From Duck Meat

Excess radicals produced by the metabolism might attack DNA and protein,and develop many chronic diseases.Synthetic antioxidants,e.g.BHT and BHA,might possess toxicity.As an effective alternative,natural antioxidant peptides have received more and more attention.Hydrolysis is the major method for preparing antioxidant peptides.Duck meat is abundant in protein,but so far,research on duck meat-derived antioxidant peptides have been rarely reported.In this respect,antioxidant peptides from duck meat were prepared by hydrolysis technique.Hydrolysate was purified by ultrafiltration,gel filtration chromatography,and semi-preparative liquid chromatography,and identified by liquid chromatography-tandem mass.Peptide sequences were synthesized and their antioxidant activities were determined.Antioxidant capacity of peptides in Caco-2 cells were also evaluated using ROS radical scavenging activity,cellular antioxidant activity(CAA value),antioxidant enzymes activities and malondialdehyde(MDA)content.Specific research contents and conclusions of this article were as follows:1.Study on preparation of antioxidant peptides from duck meat by hydrolysisCheap proteases including alcalase,neutrase and papain were selected as experimental enzymes in this study.DPPH radical scavenging capacity was used as an indicator.Hydrolysate prepared by neutrase possessed the strongest radical scavenging capacity.The hydrolysis conditions were optimized by single-factor experiments and response surface method(RSM),and appropriate modifications were performed considering the actual condition.Verification experiment was then carried out and the model was reliable.Optimal hydrolysis conditions were:enzyme dosage 1500 U/g,hydrolysis time 1 h,hydrolysis temperature 35? and hydrolysis pH 6.5.DPPH radical scavenging capacity of hydrolysate was 69.53±1.48%.2.Study on purification,identification and structure-activity relationship of antioxidant peptides from duck meatPeptide component was purified by ultrafiltration,gel chromatography and semi-preparative liquid chromatography.Amino acid sequence was identified by Nano-LCESI-LTQ-Orbitrap MS/MS.11 novel and traceable antioxidant peptide sequences were sequenced.These peptides were synthesized and their antioxidant effects were measured.AGPSIVH displayed the best DPPH inhibition,LLCVAV exhibited active reducing power,and FLLPH and LLCVAV were effective ABTS scavengers.3.Study on intracellular antioxidant activity of antioxidant peptides from duck meatAntioxidant capacity of active peptide components in oxidized Caco-2 cells(intestinal epithelial cell model)was investigated.Hydrogen peroxide(H2O2)was used as an oxidative stress inducer.Results showed that peptides did not have significant toxicity,scavenged ROS radicals,enhanced antioxidant enzymes activities and inhibited lipid peroxidation in Caco-2 cells.This indicated that antioxidant peptide from duck meat was an effective antioxidant stress inhibitor,and could be used as the component of functional foods.