Preparation of soybean anti-oxidation polypeptides by extrusion processing combined with enzymatic hydrolysis

• 1、The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
• 2、Jiangsu Quanying Biotechnology Co. ,Ltd., Suqian 223800, China

Abstract：In order to obtain soybean peptide with high antioxidant activity, soy protein isolate (SPI) was pretreated by extrusion, and then alcalase was used to carry out further hydrolysis to prepare soybean antioxidant polypeptides. The results showed that extrusion pretreatment destroyed the spatial structure of SPI, such as α-helix disappeared, random curl appeared, β-sheet content decreased and β-turn content increased, making the structure more disordered, which was beneficial to the hydrolysis of protease. The optimum conditions for the preparation of soybean anti-oxidation polypeptides (ESPIH)by extrusion processing combined with enzymatic hydrolysis were as follows: substrate concentration was set to 70 mg/ml, temperature was set to 40 ℃, pH was set to 9, substrate-enzyme (S:E, g:g) was set to 4:100, time was set to 20 min, and the scavenging rate of DPPH was up to 90.81%. The scavenging rates of DPPH, superoxide radicals, and hydroxyl radicals and total reducing power of ESPIH were significantly higher than SPIH at different concentrations. The above-mentioned results indicated that extrusion pretreatment could change the secondary structures of soy protein and was an effective mean to enhance the antioxidant activity of soybean peptide.

Keywords： extrusion enzymatic hydrolysis anti-oxidation activity