FOOD SCIENCE ›› 2018, Vol. 39 ›› Issue (20): 268-277.doi: 10.7506/spkx1002-6630-201820039

• Processing Technology • Previous Articles     Next Articles

Preparation of Antioxidant Polypeptides from Highly Denatured Soybean Meal by Ultrasonic-Assisted Enzymatic Hydrolysis

YU Donglei1, LI Tingting1, WU Haibo1,2, ZHU Xiuqing1,2,*, SHI Yanguo3,*, WAN Zhaoxiang1, LIU Chuncheng1   

  1. (1. College of Food Science, Northeast Agricultural University, Harbin 150030, China;2. National Soybean Engineering Technology Research Center, Harbin 150028, China;3. College of Food Engineering, Harbin University of Commerce, Harbin 150076, China)
  • Online:2018-10-25 Published:2018-10-24

Abstract: Antioxidant peptides were prepared from highly denatured soybean meal by successive ultrasonic-assisted cellulase hydrolysis and protease hydrolysis in this study. The optimization of the process conditions was carried out using one-factor-at-a-time method and response surface methodology. The optimal conditions for ultrasonic-assisted cellulase hydrolysis were determined as follows: ultrasonic power 300 W, irradiation time 20 min, substrate concentration 8.36 g/100 mL, enzyme dosage 666 U/g, and pH 4.1. Under these conditions, the contents of soluble peptides and polysaccharides in the hydrolysate were (18.51 ± 0.36)% and (10.83 ± 0.32)%, respectively. The hydrolysate was then further hydrolyzed with alkaline protease, and the optimal hydrolysis conditions were obtained as follows: enzyme dosage 61 900 U, pH 9, hydrolysis duration 3 h, and temperature 56.4 ℃. The contents of soluble polypeptide and polysaccharide in the final product prepared under the optimized conditions were (25.47 ± 0.81)% and (13.22 ± 0.49)%, respectively. After purification by ethanol precipitation, DEAE-cellulose 52 ion exchange chromatography and Sephadex G-25 gel chromatography, the hydrolysis product was tested for antioxidant activity. The yield of purified antioxidant polypeptides was 2.18%. The ferric reducing power and superoxide anion radical scavenging capacity of the polypeptides at 1 mg/mL was determined to be (0.495 ± 0.042) mmol/g and (17.02 ± 0.22) U/g, respectively.

Key words: highly denatured soybean meal, ultrasonic-assisted enzymatic hydrolysis, antioxidant products

CLC Number: