Optimization of enzymatic protein hydrolysis conditions of okara with endopeptidase Alcalase
2017
Ida, E. I. | Sbroggio, M. F. | Kurozawa, L. E. | Montilha, M. S. | Figueiredo, V. R. G.
The production of soymilk and tofu results in an insoluble residue called okara that present 23% of soybean protein. The objective of this study was to optimize the protein hydrolysis conditions of okara with Alcalase@ endopeptidase. A central composite rotational design was carried out to evaluate the influence of enzymatic reaction temperature (40 - 70°C), enzyme:substrate ratio(1.0 - 10.0%, g enzyme/100 g protein) and pH (7.0 - 9.0) on the degree of hydrolysis (DH).Kinetic of reaction curves (DH versus time) were characterized by high initial reaction rates followed by decreases in the reaction rate up to the stationary phase. By the response surface methodology, the process of hydrolysis was optimized in order to get higher values of DH. The results showed a quadratic dependence of DH in respect to all independent variables. The optimum condition of enzymatic hydrolysis was 55°C, enzyme:substrate ratio of 8.8% and pH9.0. Under this condition, a experimental DH of 37.3% was obtained and the predicted model was validated. In addition, the pretreatment of okara using ultrasound was evaluated, aiming to increase the DH. There was significant difference (p < 0.1) on DH value (38.8%) obtained at optimum condition, increasing 4%.
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