不同pH及离子强度对葡萄籽分离蛋白功能特性的影响

Effects of different p H and ionic strength on functional properties of grape seed protein isolate

以葡萄酒酿造完成后的废弃料赤霞珠葡萄籽为原料,对葡萄籽蛋白质在不同p H及离子强度下的功能特性和亚基组成进行了研究。结果表明:在p H为12,离子强度为0.01时溶解性较好。在等电点附近,葡萄籽分离蛋白的乳化性、溶解性较差。葡萄籽分离蛋白在低盐浓度下有较好的溶解性和乳化性、起泡性、泡沫稳定性;由SDS-PAGE分析可知,在碱性条件下,随pH的升高,葡萄籽分离蛋白亚基聚集,形成了大分子质量的可溶性聚集体,正是这些聚集体的形成造成了溶解度的增加。在低离子强度下,葡萄籽分离蛋白只有部分介于43~66 ku的亚基可溶,随盐离子的不断增加,随后也进入沉淀。

In this paper,Cabernet Sauvignon grape seed was used as raw material after wine brewing,and the functional properties and subunits of grape seed protein under different pH and ionic strength were studied.The results showed that the solubility was higher at pH 12 and the ionic strength was 0.01.The emulsification and solubility of grape seed protein isolate were lower near the isoelectric point.Grape seed protein isolate has high solubility and emulsification,foaming and foam stability at low salt concentration;SDS-PAGE analysis showed that under alkaline conditions,with the increase of pH,the subunits of grape seed protein isolate aggregated and formed soluble aggregates with high molecular weight.It is the formation of these aggregates that causes an increase in solubility.At low ionic strength,only a portion of the grape seed protein isolate is soluble in the 43~66 ku subunit.The salt ions continue to increase and then enter the precipitation.