Flavourzyme酶解大豆分离蛋白对酸奶发酵酸度及流变特性的影响研究

Study on Acidity and Rheological Behaviour of Yogurt Mixed with Enzymatic Soy-protein Hydrolysate

采用3个水解度(DH分别为3.12%、5.77%和8.83%)的大豆分离蛋白Flavourzyme酶解液取代不同量的牛奶(取代度分别为5%、7.5%和10%)用于酸奶发酵,探讨酸奶在发酵过程中的酸度变化和表观粘度变化,研究发酵酸奶在不同剪切速率下的切应力、流变指数和粘度系数。研究结果表明:当DH8.83%的大豆分离蛋白酶解产物替代7.5%～10%的牛奶时,其达到发酵终点所需时间最短。在牛奶中添加10%的DH3.12%大豆分离蛋白的水解产物能显著增加发酵酸奶的表观粘度。采用大豆分离蛋白酶解液替代部分牛奶生产酸奶能有效降低酸奶的柔性,其质构特性属于非牛顿流体。用DH3.12%大豆分离蛋白酶解液代替10%牛奶生产的酸奶在高剪切速率下其切应力远大于对照组。

Acidity change and apparent viscidity change of yogurt mixed with different amount （5%,7.5% and 10%） and different hydrolytic degree （3.12%,5.77% and 8.83%） pea-protein hydrolysate by Flavourzyme were studied in this paper. Rheological shear stress, parameter and viscosity index in different shear rate were studied in yogurt.The result showed that it took shortest time to be the fermentive and for yogurt when milk was mixed with 7.5%～ 10% enzymatic soy-protein hydrolysate which hydrolytic degree was 8.83%. The apparent viscidity of fermented yogurt was increased when milk was mixed with 10% DH 3.12% enzymatic soy-protein hydrolysate. Flexibility of yogurt was reduced when milk mixed with soybean hydrolysate and the yogurt was non-newtonian fluid. Shear stress of yogurt in high shear rate was far higher than CK when milk was mixed with DH 3.12% enzymatic soy-protein hydrolysate.