谷氨酰胺转移酶对大豆分离蛋白膜性能的影响

研究注模前酶作用时间对谷氨酰胺转移酶(TGase)改性大豆分离蛋白(SPI)膜性能的影响。在注模之前，将TGase(8U/g SPI)加入到成膜溶液中，分别在磁力搅拌下作用0、30、60、120min，然后注模成膜。利用质构仪检测蛋白膜的机械性能，结合哈克流变仪的动态黏弹实验及SDS-PAGE 实验进一步分析。注模前适度的酶作用(≤60min)在一定程度上有利于TGase 改性的SPI 膜机械强度的提高，特别是抗拉强度(TS)值；但是，时间不宜过长，因为注模前的酶作用也会诱导SPI 蛋白组分的聚沉反应，从而降低成膜溶液中可溶解蛋白的含量。结果表明，TGase改性SPI 膜时，一方面会诱导蛋白交联；另一方面，交联过多又会导致沉淀；在利用TGase 提高SPI 膜的机械性能时如何把握两者之间的关系，在交联的同时抑制酶促聚沉非常重要。

Effect of Transglutaminase on Properties of Soy Protein Isolate Film

Effect of transglutaminase (TGase) reaction time on the properties of TGase-modified soy protein isolate (SPI) films before casting was studied. Moderate TGase reaction of film-forming solution (≤ 60 min) before casting facilitated the improvement of mechanical properties of SPI films, especially the tension strength (TS) value. However, TGase reaction time should not be excessively extended, because precasting TGase reaction could result in the aggregation of SPI components and decrease of soluble protein content. When TGase was used to modify SPI films, on the one hand, TGase reaction could induce the cross-linking of protein; on the other hand, excessive cross-linking could lead to the precipitation of protein. Therefore, appropriate reaction time for inhibiting aggregation induced by TGase during the cross-linking of protein is very important for TGase-modified SPI film.