亚硫酸钠处理对小麦面筋蛋白特性的影响

Effect of Na_2SO_3 on the Properties of Wheat Gluten Protein

小麦面筋蛋白用食品级亚硫酸钠处理后,其游离巯基、二硫键以及总巯基的数量发生了变化,进而导致蛋白质的表面疏水性、热特性、水解度、溶解度和乳化性的改变。结果表明,随着亚硫酸钠浓度的增加,面筋蛋白中二硫键含量降低,巯基含量升高,而总巯基含量保持平稳;处理后的面筋蛋白疏水性得到改善,当亚硫酸钠含量为1.0 mg/g时疏水性达到最大值33.68;原始样品的热特性参数值均高于处理后的样品,处理组变性温度先下降到59.8℃后升高到63.37℃,当亚硫酸钠含量为1.0 mg/g时的热焓值最小;初始时水解速率最大,而各样品的水解度值无明显差异,随着酶解时间的延长,水解度均不断增大并逐渐趋于平衡,原始样品与处理组的差距也加大,样品6的水解度高达16.99%;溶解度不断提高,乳化活力指数由8.7 m2/g提高到34 m2/g,乳化稳定性则由最初的4.8 min提高到14.8 min,提高趋势逐步趋于平缓。

The disulphide bond, free sulfhydryl group, and total sulfhydryl group contents of wheat gluten protein had changed after being treated with Na2SO3 of different concentrations, which resulted in altered surface hydrophobicity,thermal characteristics, degree of hydrolysis, solubility, and emulsifying activity. The results showed that the free sulfhydryl groups of wheat gluten protein increased and the disulphide bonds decreased, while the total sulfhydryl groups changed little to some degree. The hydrophobicity had been improved and reached a maximum（33.68） when the concentration of Na2SO3 was 1.0 mg/g; The thermal characteristic parameters of original sample were higher than those treated with Na2SO3, the denaturation temperature first decreased to 59.8 ℃ and then increased to 63.37 ℃, the enthalpy was the lest when the sample was treated with 1.0 mg/g Na2SO3; The hydrolysis rate was the highest and there was no obvious difference in hydrolysis degree among all samples at the initial stage. With the extension of enzyme solution time, the hydrolysis degree became increasing and gradually balanced while the gap widened between original sample and treated samples. Inside, the value of sample 6 run at 16.99%; The solubility had been improved. The emulsifying activity index became increasing from 8.7 m2/g to 34.0 m2/g and emulsion stability was from 4.8 min to 14.8 min.