Abstract:In this paper，the chicken breast was used as the experimental material to extract the myofibrillar protein，and then the peptide was prepared by enzymatic hydrolysis.Based on the single factor experiment，the response surface methodology was used to optimize the myofibrillar protein resistance.The enzymatic hydrolysis process of the oxidized peptide and the identification of the secondary structure of the prepared antioxidant peptide.The results showed that pepsin was the best enzyme for preparing antioxidant peptides；the optimal enzymatic hydrolysis conditions for the preparation of antioxidant peptides by response surface method were pH 2.5 and temperature 35℃.The time was 3 h.Under this condition，the DPPH free radical clearance rate of the peptide obtained by enzymatic hydrolysis was up to 85.38%，the IC50was 6.674 mg/mL，the absorbance value of the reducing ability was up to 0.537，and the ABTS+free radical clearance rate was 64.73%，the IC50value was 281.575 μg/mL；the oxygen radical absorption capacity （ORAC）showed that the fluorescence intensity decayed slowly as the sample concentration increased，the sample antioxidant capacity increased with increasing concentration.Fourier transform infrared spectroscopy（FTIR）showed that the percentage of secondary structure was 15.36%for α -helix，20.22%for β -fold，39.03%for β -turn，and 25.39%for irregular curl.