Abstract:Soybean meal, the main by-product of soybean oil processing, contains almost all the proteins in soybeans and has broad application prospects. In this study, soybean meal antioxidant peptides were prepared from ultrasonic-assisted enzymatic hydrolysis. Through single factor and response surface tests, the optimum technological parameters were determined as follows: substrate concentration of 9% (mass fraction), enzyme amount of 6 665.39 U/g, enzyme hydrolysis at pH 8.0 under 50 ℃ for 4.0 h and ultrasound for 9 min under 300 W. The components with molecular weight less than 1 000 were obtained through ultrafiltration membrane and identified by LC-MS/MS. An antioxidant pentapeptide from soybean meal was obtained. Its amino acid sequence was Ile-Trp-Asn-Leu-Asn (IWNLN), and the IC50 value of ABTS radical scavenging ability was （0.06±0.003） mg/mL. At a concentration of 0.01 mg/mL, the ORAC value was （7.614±0.138） mg TE/mg, and the IC50 value of hydroxyl radical scavenging ability was （0.008±0.001） mg/mL. This study provides an experimental basis for the optimization of production process and the confirmation of functional factor sequence of soybean meal antioxidant peptide, and provides a new idea for the development of soybean meal protein peptide functional products.
