不同的二价阳离子(Ca^(2+)、Mg^(2+)、Zn^(2+))对大豆蛋白分级效果的影响

Effect of different divalent cations(Ca^(2+),Mg^(2+),Zn^(2+)) on fractionation of soy protein

向脱脂豆浆中加入不同的二价阳离子(Ca2+、Mg2+、Zn2+),考察它们在大豆蛋白分级过程中对去除亲脂性蛋白的效果。结果显示,三种离子的加入均降低了样品的蛋白提取率,同时总脂含量也有所减少,根据SDS-PAGE分析,在一定的浓度范围内,所减少的蛋白组分可能是与脂紧密结合的组分(仅限CaCl2及MgCl2的添加);同浓度的CaCl2处理所得样品总脂含量减少最多,且其蛋白提取率稍低于MgCl2处理所得样品,但高于ZnCl2处理所得样品,结合TLC分析,表明Ca2+去除亲脂性蛋白的作用效果最好,以此作为沉淀剂的最佳分级条件为:在pH7.0下添加10mmol/L的CaCl2,所得样品蛋白提取率降低了33%,但蛋白含量由88.45%增加到92.58%(干基),同时总脂含量由4.83%降低到2.01%。

Effect of different divalent cations on the removal lipophilic protein from the soy protein was compared.The results indicated that the protein recovery rates and the lipid contents were decreased using divalent cations in the fractionation process.The removed protein might be the protein fraction associated with lipids at a certain concentration of CaCl2 or MgCl2.Lipid content of the sample prepared with CaCl2 was reduced mostly,and the protein recovery rate was a little smaller than MgCl2 treatment,but significantly higher than ZnCl2 treatment.So Ca2＋ was the best precipitation agent which can remove lipophilic protein from the soy protein effectively.The optimized fractionation condition was pH7.0 in the presence of 10mmol/L CaCl2,and the protein recovery rate was decreased by 33%,whereas the protein content increased from 88.45% to 92.58%,and simultaneously the lipid content decreased from 4.83% to 2.01%.