交联羟丙基羧甲基复合改性玉米淀粉的性能研究

Properties of Corn Starch Modified by Cross-linked Hydroxypropyl Carboxymethyl Compound

摘要:

以玉米淀粉为原料，利用乙醇溶剂法进行羟丙基醚化改性，再采用环氧氯丙烷交联剂和一氯乙酸进行处理而制得复合改性淀粉。采用傅里叶变换红外谱仪、X射线衍射仪和扫描电镜等对玉米原淀粉、羟丙基淀粉、交联羟丙基淀粉、羟丙基羧甲基淀粉和交联羟丙基羧甲基淀粉的微观结构进行了表征。红外分析表明改性淀粉在1287 cm-1处出现羟丙基的吸收峰，同时在1328~1603 cm-1处出现了-COO-吸收峰，说明原淀粉已接入了羟丙基和羧甲基基团。利用X-射线衍射分析改性淀粉仍属A型衍射图，证实了反应主要发生在无定形区。复合变性前后淀粉的表观形貌变化，证实了淀粉其反应不仅发生在淀粉颗粒表面，也发生在淀粉颗粒内部。讨论了改性淀粉的理化性质，结果表明交联羟丙基羧甲基淀粉具有良好的透明性、冻融稳定性、流变性。

Abstract:

Corn starch was used to prepare hydroxypropyl starch by ethanol solvent, and then hydroxypropyl starch was modified using epichlorohydrin as cross-linked agent and chloroacetic acid as etherification agent. The microstructures of corn starch, hydroxypropyl starch, cross-linked hydroxypropyl starch, hydroxypropyl carboxymethyl starch, cross-linked hydroxypropyl carboxymethyl starch were analyzed by Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Modified corn starch showed new absorption peaks at 1287 cm-1 and 1328~1603 cm-1, which indicated that carboxymethyl and hydroxypropyl groups were attached to the native starch. A type X-ray spectra was assigned to modified starch, which confirmed the reaction mainly occurred in the amorphous region. The surface transformation change of starch granules before and after modification was observed, showing that the reaction occurred both inside and outside starch granules. Physical and chemical characteristics of modified corn starch showed that cross-linked hydroxypropyl carboxymethyl starch had good properties of transparency, freeze-thaw stability and rheology.