TG酶添加方式对乳清浓缩蛋白-羟丙基甲基纤维素复合膜成膜性能的影响

Effects of TG Addition Sequence on Property of Whey Protein Concentrate-Hydroxypropyl Methyl Cellulose Composite Films

为了研究转谷氨酰胺酶(TG)改性乳清浓缩蛋白(WPC)-羟丙基甲基纤维素(HPMC)混合膜的最佳成膜方式,文章在制备WPC-HPMC混合膜的不同阶段添加TG酶,研究复合膜和成膜溶液的成膜性能以及结构表征。将WPC与HPMC混合后添加TG酶交联,制备WPC-HPMC-TG膜。调整TG酶的添加方式,将TG酶与WPC交联后添加HPMC,制备WPC-TG-HPMC膜。SDS-PAGE结果证实TG酶可以促进蛋白质分子间发生交联,形成大分子聚合物。FTIR分析结果表明,TG酶交联乳清蛋白能够引起蛋白质二级结构发生改变。与WPC-HPMC-TG膜相比,WPC-TG-HPMC膜具有更好的机械性能和流变性能,这说明TG酶交联WPC的能力强于TG酶交联WPC-HPMC混合物。因此,TG酶合适的添加方式对改善WPC-HPMC混合膜的成膜特性具有积极的影响。

The objective of this research was to investigate the optimal film formation method of transglutaminase(TG)modified whey concentrated protein(WPC)-hydroxypropyl methyl cellulose(HPMC)composite film.In this study,TG was added at different sequence of the preparation of WPC-HPMC composite film,and the film-forming properties and structural characterization of both the composite films and the film-forming solutions were studied.After WPC mixed with HPMC,TG was added to cross-link to prepare WPC-HPMC-TG film.Adjusting the addition sequence of TG,HPMC was added after TG cross-linked with WPC to prepare WPC-TG-HPMC film.The result of SDS-PAGE proved that TG could cause cross-linking between protein molecules to form macromolecular polymers.FTIR analysis confirmed TG cross-linking whey protein could cause changes in protein secondary structure.Compared with WPC-HPMC-TG film,the mechanical and rheological properties of WPC-TG-HPMC film were better,which made it clear that the ability of TG to crosslink WPC was stronger than that of TG to crosslink WPC-HPMC mixture.In conclusion,the appropriate addition sequence of TG was crucial to improve the performance of WPC-HPMC composite films.