无机盐对酶促大豆蛋白胶凝特性的影响

为了探究无机盐对大豆蛋白酶促胶凝过程热动力学特性及凝胶强度的影响规律,以大豆分离蛋白分散液(Dispersion of soybean protein isolate,DSPI,4%,m/m)为材料,以木瓜蛋白酶为凝固剂进行酶促胶凝试验,测定不同无机盐种类及浓度下的胶凝时间,并通过Arrhenius方程求出反应活化能;以凝胶强度为指标,利用Box-Behnken中心组合设计试验建立以Ca2+浓度、温度及酶添加量为参数的凝胶强度模型。结果表明添加无机盐(Na Cl、KCl、Ca Cl2、Mg Cl2和Mg SO4)可降低酶促DSPI凝胶的活化能,但Arrhenius曲线仍呈线性关系,说明无机盐可加快反应速度,但胶凝反应仍遵循同一机理;显著性检验及响应面分析表明所建凝胶强度模型拟合度较高,木瓜蛋白酶添加量对凝胶强度影响显著(P0.05),Ca Cl2添加量与温度的交互作用对凝胶强度的影响极显著(P0.01),Ca Cl2和温度同时较高或较低时,均不利于提高凝胶强度。

Effects of salts on the properties of enzymatic-induced soybean protein gels

To investigate the effects of salts on the thermal dynamic properties and gel strength of enzymatic-induced soybean protein gel, dispersions of soybean protein isolate (4%, m/m) were coagulated by papain with presence of NaCl, KCl, CaCl2, MgCl2 and MgSO4 at various concentrations respectively. Then the gelling time and gel strength were determined accordingly. Arrehnou plot was dserived from the gelling time as the function of temperature. A gel strength model was established via Box-Behnken center-united design experimentation considering the three parameters: the concentration of Ca2 , gelling temperature and the amount of papain. The results showed that adding salts (NaCl, KCl, CaCl2, MgCl2 and MgSO4) lowered the activation energy of gelation. However, the Arrhenius plot kept linear relationship, which suggested same gelation mechanism. According to the results of significance analysis, the gel strength mold displayed a good fitness. The response surface analysis revealed that the amount of papain affected the gel strength significantly (p<0.05) and the interaction of the Ca2 concentration and temperature highly significantly (p<0.01). When the values of temperature and Ca2 concentration were simultaneously higher or lower would both result lower gel strength.