Li Ning, Zhang Zhihui, Cui Yifan, Shi Jiahui, Sun Xiaotong, Liu Yi-An, Wang Xibo, Xu Ning
College of Food Science, Northeast Agricultural University, Harbin, China.
College of Agriculture, Northeast Agricultural University, Harbin, China.
J Sci Food Agric. 2023 Jan 30;103(2):811-819. doi: 10.1002/jsfa.12192. Epub 2022 Sep 12.
Using transglutaminase (TGase) is a new method to improve protein properties in order to promote protein glycosylation. This article mainly studies soy protein isolate (SPI) and glucosamine to improve the freeze-thaw stability of emulsion under the action of TGase. The degree of glycosylation was studied by the content of free amino groups and the degree of conjugation. The optimal conditions for preparing soy protein isolate-glucosamine (SPI-G) conjugate were determined by a response surface optimization model based on single-factor experiments using the creaming index of the emulsion after the first freeze-thaw cycle as the response value.
The results showed that the emulsion had the lowest creaming index when the conditions of protein concentration was 20 g L , mass ratio of SPI-G was 5:3 (w/w), enzyme addition amount was 10 U g , and reaction time was 2 h. The optimized modified product was measured for the creaming index after the first freeze-thaw cycle. It was found that the creaming index of the modified product SPI-G after the first freeze-thaw cycle was 9.02%, which was less than and close to the optimized model predicted value. The creaming index and optical microscopy results after three freeze-thaw cycles confirmed that the freeze-thaw stability of the SPI-G samples was significantly enhanced after optimization of the response surface model.
It showed that glycosylation promoted by TGase could improve the freeze-thaw stability of SPI emulsion, thereby broadening the application of SPI in food. © 2022 Society of Chemical Industry.
使用转谷氨酰胺酶（TGase）是改善蛋白质特性以促进蛋白质糖基化的一种新方法。本文主要研究大豆分离蛋白（SPI）和氨基葡萄糖在TGase作用下对乳液冻融稳定性的改善。通过游离氨基含量和共轭程度研究糖基化程度。以首次冻融循环后乳液的乳析指数为响应值，在单因素实验基础上，通过响应面优化模型确定制备大豆分离蛋白 - 氨基葡萄糖（SPI - G）共轭物的最佳条件。
结果表明，当蛋白质浓度为20 g·L、SPI - G质量比为5:3（w/w）、酶添加量为10 U·g且反应时间为2 h时，乳液的乳析指数最低。对优化后的改性产物进行首次冻融循环后的乳析指数测定。发现改性产物SPI - G首次冻融循环后的乳析指数为9.02%，小于且接近优化模型预测值。三次冻融循环后的乳析指数和光学显微镜结果证实，响应面模型优化后SPI - G样品的冻融稳定性显著提高。
结果表明，TGase促进的糖基化可提高SPI乳液的冻融稳定性，从而拓宽SPI在食品中的应用。© 2022化学工业协会。
