微波-超声辅助乳清分离蛋白糖基化工艺优化

Optimization of Microwave-Ultrasound Assisted Glycosylation Process of Whey Protein Isolate

为提高湿美拉德法低聚半乳糖(galactooligosaccharides,GOS)糖基化改性乳清分离蛋白(whey protein isolate,WPI)的接枝度并减少反应过程中副产物的产生,采用短时微波-超声蛋白改性和低温水浴糖基化的方法,考察微波-超声次数、WPI∶GOS(质量比)、水浴温度、水浴时间对GOS改性WPI的接枝度和乳化性能的影响。以接枝度为响应值,优化WPI-GOS缀合物制备工艺。优化结果为微波-超声3次、WPI∶GOS(质量比)2.8∶1、水浴温度61.3℃、水浴时间61.7 min。该工艺下,WPI-GOS接枝度为(62.48±0.74)%,GOS对WPI结构与功能改性效果明显,WPI-GOS缀合物具有较好的乳化性能、pH稳定性和热稳定性,反应产物白度高,褐变程度低。该研究结果可为蛋白糖基化改性提供一种新的方法和理论依据。

In order to improve the grafting degree of whey protein isolate(WPI)modified by glycosylation of galactooligosaccharides(GOS)by wet Maillard method and reduce the production of by-products during the reaction,the method of short-time microwave-ultrasound protein modification and low-temperature water bath glycosylation is used to investigate the effects of microwave-ultrasound times,WPI∶GOS(mass ratio),water bath temperature and water bath time on the grafting degree and emulsification performance of WPI modified by GOS.With grafting degree as the response value,the preparation process of WPI-GOS conjugate is optimized.The optimization results are as follows:microwave-ultrasound for three times,WPI∶GOS(mass ratio)is 2.8∶1,water bath temperature is 61.3℃and water bath time is 61.7 min.Under such process,the grafting degree of WPI-GOS is(62.48±0.74)%.GOS has a significant effect on modifying the structure and function of WPI,and the WPI-GOS conjugate has good emulsification performance,pH stability and thermal stability.The product has high whiteness and low browning degree.The results can provide a new method and theoretical basis for protein glycosylation modification.