漆酶诱导大豆分离蛋白-甜菜果胶双网络凝胶的构建

大豆分离蛋白是食品工业中常用的凝胶材料,但其对环境较为敏感,所成凝胶具有机械性能单一,成形性较差等缺点,而多糖对蛋白质的修饰可以改善蛋白质的凝胶性质。本研究通过向大豆分离蛋白中添加适量甜菜果胶,调节大豆分离蛋白和甜菜果胶浓度来构建双网络凝胶,以达到改善蛋白质单一网络凝胶的机械和质构特性的目的。实验中通过酶促和加热两步处理,得到大豆分离蛋白-甜菜果胶双网络凝胶。随着大豆分离蛋白浓度的提高,双网络凝胶的弹性也随之提高。而甜菜果胶浓度越高,双网络凝胶的硬度和咀嚼性越大。当大豆分离蛋白浓度为11%,甜菜果胶浓度为1.5%,加酶量为100 nkat/g底物时,所获的凝胶具有最高的持水率(95.28%)。当大豆分离蛋白浓度为8%,甜菜果胶浓度为2.5%,加酶量为100 nkat/g底物时,双网络凝胶的硬度和咀嚼性分别为4.25/g和4.06/J。大豆分离蛋白-甜菜果胶双网络凝胶的构建,改善了凝胶的机械性能及持水能力,形成了更加有序的三维网状结构。

Laccase-induced Construction of Edible Double-network Gels Based on Soy Protein and Sugar Beet Pectin

Soy protein isolate is commonly used as a gel material in the food industry. However, it is sensitive to the environment, with low mechanical property and poor formability. The gelation properties of the proteins could be improved by protein modification using polysaccharides. In the present study, an appropriate amount of sugar beet pectin was added to soy protein isolate, and the concentrations adjusted to construct double-network gels, in order to achieve the goal of improving the mechanical and textual properties of the protein single-network gel. A two-step process (thermal treatment and laccase catalysis) was applied to the construction of double-network gel. With increasing concentrations of soy protein isolate, the springiness of the double-network gel was improved; with increasing concentrations of sugar beet pectin, the hardness and chewiness of the double network gel was enhanced. When the concentration of soy protein isolate was 11%, the concentration of sugar beet pectin was 1.5%, and the enzyme dosage was 100 nkat/g substrate, the highest water holding capacity (95.28%) of the double network gel was achieved. When the concentration of soy protein isolate was 8%, the concentration of sugar beet pectin was 2.5%, and the enzyme dosage was 100 nkat/g substrate, the hardness and the chewiness of the double network gel were 4.25/g and 4.06/J, respectively. The construction of soy protein isolate-sugar beet pectin double-network gels improved the mechanical property and water holding capacity of gels, resulting in the formation of a more ordered gel network structure.