戊二酸酐酯化κ-卡拉胶的制备及理化性质

Preparation and Physicochemical Properties of Glutaric Acid Esterifiedκ-Carrageenan

以κ-卡拉胶为原料,戊二酸酐为酯化剂,探讨了戊二酸酐酯化卡拉胶(GC)的制备过程中戊二酸酐浓度、反应pH、反应温度、卡拉胶浓度和反应时间对产物取代度的影响,得到制备GC的工艺条件:戊二酸酐浓度4%,反应pH8~8.5,反应温度30℃,卡拉胶浓度7.50%,反应时间2 h,取代度为0.077。利用红外光谱、白度仪、粘度仪、扫描电镜和热重分析仪对产物进行表征。结果表明:GC在红外光谱1734 cm-1和在1576 cm-1处峰具有明显的酯羰基和羧基吸收特性,峰值随着取代度的增加更加明显;与原卡拉胶相比,酯化卡拉胶粉末白度略微增加,颗粒表面变得粗糙,表层出现一定凹陷和孔洞,而热稳定性影响不明显;酯化卡拉胶溶液粘度降低,但乳化性及乳化稳定性均得到显著提升(P<0.05)。κ-卡拉胶经戊二酸酐酯化后,改变了其结构与性质,拓宽了κ-卡拉胶的应用范围。

The effects of the concentration of glutaric anhydride,pH value,reaction temperature,carrageenan concentration and reaction time on the degree of substitution(DS)of the product in the preparation of glutaric acid esterified carrageenan(GC)withκ-carrageenan as raw material and glutaric anhydride as esterification agent were studied.The technological conditions for the preparation of GC were obtained as follows:glutaric anhydride concentration 4%,pH value 8~8.5,reaction temperature 30℃,carrageenan concentration 7.50%,reaction time 2 h,DS 0.077.The products were characterized by IR,whiteness,viscosity,scanning electron microscopy and thermogravimetry.The results showed that:the absorption characteristic peaks of ester carbonyl and carboxyl groups appeared in curve of GC at 1734 cm-1 and 1576 cm-1,and the peaks increased with the increase of DS.Compared with the original carrageenan,the whiteness of esterified carrageenan powder increased slightly,the surface of the particles becomed rough,and there were some depressions and holes in the surface layer,but the effect of thermal stability is not obvious;the viscosity of the esterified carrageenan solution decreased,but the emulsifying property and emulsifying stability were improved significantly.Taken together,after esterification with glutaric anhydride,the structure and properties ofκ-carrageenan are changed and the application range ofκ-carrageenan is widened.