羟丙基戊二酸酯复合改性木薯淀粉的性质分析

Analysis of the Properties of Cassava Starch Modified by Hydroxypropylation and Glutaric Anhydride Esterification

摘要:

以木薯淀粉为原料，利用乙醇溶剂法先进行羟丙基醚化改性，再采用戊二酸酐作酯化剂进行处理而制得复合改性淀粉。采用傅里叶变换红外谱仪（FT-IR）、扫描电镜（SEM）和DV-I Prime旋转粘度仪等对样品的微观结构进行表征及其性能分析。红外分析表明改性淀粉在1287 cm-1处出现羟丙基的吸收峰，羟丙基戊二酸复合改性淀粉在1733 cm-1处和1555 cm-1处出现新的酯化吸收峰，说明原淀粉已接入了羟丙基和戊二酸基团。复合变性前后淀粉的表观形貌变化，证实了反应不仅发生在淀粉颗粒表面，也发生在淀粉颗粒内部。旋转粘度仪分析则表明了复合改性后的羟丙基戊二酸酯淀粉的粘度和抗流变性有很大的提升，当DS为0.0362时，淀粉糊的粘度为12100 mPa·s，比羟丙基木薯的粘度提高了6.72倍（羟丙基木薯淀粉的粘度为1800 mPa·s）。

Abstract:

Using cassava starch as the raw material, hydroxypropyl starch was prepared using the ethanol solvent method, and dually modified starch was obtained after the hydroxypropyl starch was treated with glutaric anhydride as an etherification agent. The microstructure and properties of the starch sample were investigated by Fourier transform infrared spectrometer (FT-IR), scanning electron microscope (SEM), and DV-I Prime rotational viscometer. The FT-IR results showed a new hydroxypropyl absorption peak at 1287 cm-1 in the hydroxypropyl starch, and new esterification absorption peaks at 1733 cm-1 and 1555 cm-1 in the hydroxypropyl-glutaric anhydride dually modified starch, which indicated that glutaric acid functional groups and hydroxypropyl groups were attached to the native starch. The surface morphology changes of starch granules before and after the dual modification indicated that the reaction occurred on both the surface and the interior of the starch granules. The rotational viscometry results indicated that the viscosity and rheological properties of the hydroxypropyl-glutaric anhydride-modified starch were significantly improved after the dual modification. When the degree of substitution (DS) was 0.0362, the paste viscosity increased from the original 1800 mPa·s to 12100 mPa·s, which was 6.72 times that of the hydroxypropyl starch.