| Popis: |
为改善大豆分离蛋白膜的性能，利用碱性蛋白酶制备玉米醇溶蛋白酶解产物（ZH），通过转谷氨酰胺酶（TGase）催化大豆分离蛋白（SPI）与ZH发生交联反应，对反应条件进行了优化；通过控制反应时间得到4种修饰产物（分别为0 h-SPI/ZH、0.5 h-SPI/ZH、1 h-SPI/ZH、1.5 h-SPI/ZH），并对修饰产物制备的膜性能进行研究。结果表明：最佳的TGase催化SPI与ZH交联反应条件为SPI与ZH质量比3.5∶ 1、底物质量浓度40 mg/mL、pH 7.5、酶添加量10 U/g（以蛋白质质量计）、反应温度45 ℃、反应时间1.5 h；随着反应时间的延长，4种修饰产物制备的复合膜抗拉强度和不透明度增加，含水量、断裂伸长率和水蒸气透过率降低；与SPI膜相比，1.5 h-SPI/ZH制备的复合膜的抗拉强度增加了5.5%，含水量与水蒸气透过率分别下降了25.6%和32.2%，不透明度增加了114.2%。综上，采用TGase催化SPI与ZH发生交联，所制的复合膜综合品质较好，为SPI复合膜的开发提供了技术支持。 In order to improve the properties of soybean protein isolates film, the enzymatic hydrolysates of zein (ZH) was prepared by alkaline protease. The cross-linking reaction between soybean protein isolates (SPI) and ZH was catalyzed by transglutaminase (TGase), and the reaction conditions were optimized. Four modified products(0 h-SPI/ZH, 0.5 h-SPI/ZH, 1 h-SPI/ZH, and 1.5 h-SPI/ZH) were obtained by controlling the reaction time, and the properties of the film produced by the modified products were investigated. The results showed that the optimal reaction conditions were as follows: mass ratio of SPI to ZH 3.5∶ 1, substrate mass concentration 40 mg/mL, pH 7.5, TGase addition 10 U/g(based on the mass of protein), reaction time 1.5 h and reaction temperature 45 ℃. With the prolonging of reaction time, the tensile strength and opacity of the composite film prepared by the four modified products increased, while the water content, elongation at break and water vapor transmission rate decreased. Compared with SPI film, the tensile strength of the composite film prepared by 1.5 h-SPI/ZH increased by 5.5%, the water content and water vapor transmission rate decreased by 25.6% and 322%, respectively, and the opacity increased by 114.2%. In conclusion, the overall quality of the composite film prepared by TGase catalyzed cross-linking of ZH and SPI is good, providing technical support for the development of SPI composite film. |
