植物单宁酸交联明胶的条件优化及性质分析

Optimization of cross-linking conditions for gelatin with vegetative tannic acid and analysis for its properties

该文用单宁酸作交联剂对明胶进行交联改性,通过响应面法优化反应条件并建立回归模型,并对交联前后的明胶进行十二烷基磺酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)、紫外光谱和黏度等3方面的分析测定,确认单宁酸交联对明胶所产生的交联作用,开发新食品配料交联明胶。结果显示:适宜的交联反应条件为反应温度47.5℃,时间50h,单宁酸添加量80mg/g明胶。性质分析表明,与原料明胶相比交联明胶一些性质发生变化,紫外光谱分析发现交联明胶在276nm出现新吸收峰,表明交联明胶分子中存在苯环;电泳后交联明胶的蛋白质条带色泽明显变浅,且交联度越大条带色泽越浅,此外,交联明胶溶液的黏度明显增大,说明单宁酸交联处理使交联明胶中有更多的大分子物质生成。

Gelatin was modified with tannic acid as a cross-linker in this study.Cross-linking conditions of gelatin were optimized by response surface methodology and corresponding regression model was thus established.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)analysis,ultraviolet absorption spectrum analysis and viscosity determination were conducted to confirm the cross-linking of gelation by tannic acid.The results showed that the optimal cross-linking conditions were as follow:reaction temperature was 47.5℃,reaction time was 50 h and addition level of cross-linker was 80mg·g -1 on gelatin basis.Compared to those of gelatin,some properties of cross-linked gelatin were changed.Ultraviolet absorption spectrum analysis showed that cross-linked gelatin had an additional absorption peak at 276 nm,which indicates the existence of benzene rings in cross-linked gelatin.It was also found that the color of protein bands of cross-linked gelatin in SDS-PAGE analysis became lighter when cross-linking degree of gelatin increased,and relative viscosity of cross-linked gelatin solution increased clearly.All results indicate the formation of higher molecules in cross-linked gelatin as the result of treatment of gelatin with tannic acid.