Effect of pulsed electric field (PEF) on structures and antioxidant activity of soybean source peptides-SHCMN

•DPPH radical inhibition of antioxidant peptides SHCMN were improved by PEF technology.•Effects on structures of SHCMN was investigated.•The α helix, random coil, β turn and functional groups of SHCMN was analyzed.•Conditions of PEF proceeding were optimized by TFAT. Recently, high-intensity pulsed electric field (PEF) has successfully used in improvement of antioxidant activity. Ser-His-Cys-Met-Asn (SHCMN) obtained from soybean protein was chosen to investigate the phenomenon of antioxidant activity improvement. Effects of PEF treatment on antioxidant activity of SHCMN were evaluated by DPPH radical inhibition. Nuclear magnetic resonance (NMR), mid-infrared (MIR), circular dichroism (CD) were used to analyze structures of SHCMN. Two-factor-at-a-time results show that DPPH radical inhibition of SHCMN is significantly (P