限制性酶水解对大豆分离蛋白乳状液酸诱导凝胶的影响

Effect of limited enzymatic hydrolysis on the acid-induced gel of soybean protein isolate emulsion

旨在为生产质量更高、口感更佳的大豆基酸奶类产品提供理论指导,采用不同蛋白酶(木瓜蛋白酶、菠萝蛋白酶、中性蛋白酶、风味蛋白酶、胃蛋白酶)对大豆分离蛋白(SPI)进行限制性酶水解处理,以SPI水解物及其对照品未经酶水解的SPI(HUE)为原料制备SPI乳状液酸诱导凝胶,对HUE和SPI水解物的亚基组成及分子质量进行表征,并分析了限制性酶水解对SPI乳状液酸诱导凝胶机械性能、摩擦学特性以及微观结构的影响。结果表明:经木瓜蛋白酶水解后SPI的7S、11S组分几乎完全消失,经菠萝蛋白酶、中性蛋白酶、风味蛋白酶水解后SPI的7S组分明显减少,11S组分无明显变化,经胃蛋白酶水解后SPI的11S组分几乎消失,而7S组分无明显变化;与HUE制备的凝胶相比,经酶水解后SPI制备的凝胶其硬度和摩擦系数均降低,经木瓜蛋白酶水解后制备的凝胶网络结构不均匀,持水力降低,而经风味蛋白酶水解后制备的凝胶的持水力和微观结构的均匀程度提高。综上,经过合适的蛋白酶适当水解,可以制备硬度更低、持水力更好、摩擦系数更低、微观结构更均匀的SPI乳状液酸诱导凝胶。

To provide theoretical guidance for the production of soybean based yogurt products with higher quality and better taste,soybean protein isolate(SPI)was subjected to limited enzymatic hydrolysis by different proteases(papain,bromelain,neutral protease,flavor protease,pepsin),and the SPI hydrolysates and the control samples HUE(no enzymolysis)were used to prepare acid-induced gel.The subunit composition and molecular weight of HUE and SPI hydrolysates were characterized.The effects of limited enzymatic hydrolysis on the mechanical properties,tribological properties and microstructure of acid-induced gel prepared by SPI emulsion were analyzed.The results showed that the 7S and 11S components of SPI almost disappeared after papain hydrolysis.The 7S components of SPI hydrolyzed by bromelain,neutral protease and flavor protease decreased significantly,while the 11S components had no significant change.After hydrolysis with pepsin,the 11S components of SPI almost disappeared,while the 7S components had no obvious change.Compared with the gel prepared with HUE,the hardness and friction coefficient of the acid-induced gel prepared with SPI hydrolysates decreased,the gel prepared with SPI hydrolysates by papain hydrolysis exhibited uneven network structure and reduced water holding capacity,while the gel prepared by flavor protease hydrolysis showed improved water holding capacity and microstructure uniformity.In conclusion,acid-induced gel prepared with SPI emulsion with lower hardness,better water holding capacity,lower friction coefficient and more uniform microstructure can be prepared by proper hydrolysis of appropriate proteases.