3种马铃薯改性淀粉的理化性质及结构分析

Physico-chemical Properties and Structural Analysis of Modified Potato Starch

以马铃薯淀粉为材料,制备氧化淀粉、醋酸酯淀粉、氧化醋酸酯淀粉,比较其理化性质,并通过红外光谱(FT-IR)、电子扫描显微镜(SEM)等对其结构进行分析。结果表明:氧化淀粉、醋酸酯淀粉、氧化醋酸酯淀粉比原淀粉透明度高、流动性好、附着力强、涂抹性好。FT-IR实验表明氧化淀粉有羧基的特征吸收峰,而氧化醋酸酯淀粉酯化改性过程中有醋酸酯基团的生成。SEM扫描实验显示氧化淀粉的外形比较规整多为球状或椭球状,表面较光滑;醋酸酯淀粉颗粒形状未发生大的改变,但规整度很差;氧化醋酸酯淀粉颗粒完整,表面粗糙,低取代度的酯化反应仅发生在淀粉颗粒表面。

Modified starches were prepared from native potato starch through introducing acetic ester groups and their structural characteristics were analyzed by FT-IR and SEM. Oxidized potato starch, potato starch acetate and oxidized potato starch acetate exhibited better transparency, adhesiveness and spreadability when compared to native potato starch. FT-IR analysis revealed the presence of characteristic absorption peak of carboxyl groups in oxidized potato starch and the formation of acetate groups in oxidized potato starch acetate. SEM observation showed the spherical or ellipsoidal shape and smooth surface of oxidized potato starch, no detectable change in the shape of potato starch acetate granules, but with poor regularity, and intact oxidized potato starch acetate granules with a low degree of substitution as a result of estertification on their rough surfaces.