title: Heat-induced inactivation mechanisms of Kunitz trypsin inhibitor and Bowman-Birk inhibitor in soymilk processing.
abstract: Trypsin inhibitor activity (TIA) is an important antinutritional factor in soymilk. In this study, the effects of NaCl preaddition on TIA and the heat-induced TIA inactivation mechanisms were examined. The results showed that Kunitz trypsin inhibitor (KTI) and Bowman-Birk inhibitor (BBI) contributed 74% and 26% to raw soymilk TIA, respectively. The heat-induced quick KTI incorporation into protein aggregates was the reason for its quick TIA inactivation. The heat-induced slow cleavage of one BBI peptide bond was the reason for its slow TIA inactivation. Heat-induced protein aggregate formation had little effect on BBI inactivation owing to the fact that BBI and its degradation product tended to remain in the supernatant (197,000g, 1h) in all conditions used in this study. NaCl could accelerate the KTI incorporation into protein aggregates and the cleavage of one BBI peptide bond, which supplied a simple and quick method for low TIA soymilk processing.
authors: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China.
authors: Yeming
authors: Y
authors: Chen
authors: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China.
authors: Zhicun
authors: Z
authors: Xu
authors: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China.
authors: Caimeng
authors: C
authors: Zhang
authors: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China.
authors: Xiangzhen
authors: X
authors: Kong
authors: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China. Electronic address: yfhua@jiangnan.edu.cn.
authors: Yufei
authors: Y
authors: Hua
mesh_terms: D003296:Cooking; D006358:Hot Temperature; D055550:Protein Stability; D041942:Soy Milk / Q000737:chemistry*; D013025:Glycine max / Q000737:chemistry*; D014358:Trypsin Inhibitor, Bowman-Birk Soybean / Q000737:chemistry*; D014361:Trypsin Inhibitors / Q000737:chemistry*
chemical_list: D014358:Trypsin Inhibitor, Bowman-Birk Soybean; D014361:Trypsin Inhibitors
keywords: Bowman-Birk inhibitor (BBI); Chymotrypsin inhibitor activity (CIA); Disulfide bond; Kunitz trypsin inhibitor (KTI); NaCl; Peptide bond cleavage; Protein aggregate; Soymilk; Trypsin inhibitor activity (TIA)