Abstract This study investigated the effect of microbial transglutaminase cross-linking on the gel properties of soybean-whey mixed protein (SPI-WPI) after ultrasonic pretreatment. The average particle size of SPI-WPI decreased with increasing of ultrasonic time treatment, and minimal particle size was verified after 45 min. Endogenous fluorescence spectroscopy and surface hydrophobicity analysis showed that the SPI-WPI conformation changed after ultrasonic treatment. The polypeptide chain partially expanded inside the protein molecule, the hydrophobic group was exposed, and the protein structure became more stretched. The gel hardness and water holding capacity of the SPI-WPI hybrid system reached a maximum 30 min after ultrasonic treatment. Fourier infrared analysis showed that the secondary structure of the protein changed after ultrasonic modification. A complex is formed between SPI and WPI, and the gel properties of the mixed protein are significantly improved, providing theoretical and technical support for the development of new mixed protein foods.

中文翻译：

---

超声预处理改善转基因微生物转谷氨酰胺酶交联大豆-乳清混合蛋白的凝胶特性

摘要 本研究研究了微生物转谷氨酰胺酶交联对超声预处理后大豆-乳清混合蛋白（SPI-WPI）凝胶特性的影响。SPI-WPI 的平均粒径随着超声处理时间的增加而减小，45 min 后验证最小粒径。内源性荧光光谱和表面疏水性分析表明，超声处理后SPI-WPI构象发生了变化。多肽链在蛋白质分子内部部分扩张，疏水基团暴露，蛋白质结构变得更加拉伸。SPI-WPI 混合体系的凝胶硬度和持水能力在超声处理后 30 分钟达到最大。傅里叶红外分析表明，超声波修饰后蛋白质的二级结构发生了变化。SPI与WPI形成复合物，混合蛋白的凝胶特性得到显着改善，为开发新型混合蛋白食品提供理论和技术支持。