甘薯淀粉辛烯基琥珀酸酯物化性质的研究

Characterization of Octenyl Succinate Anhydride Modified Sweet Potato Starch

摘要:

以甘薯淀粉为参照，采用扫描电镜分析、红外光谱、差示扫描量热分析、快速粘度分析等现代仪器分析方法对甘薯淀粉辛烯基琥珀酸酯的颗粒形貌、结构特征、热力学特性、黏度特性等物化性质进行了测定和研究。结果表明，甘薯淀粉经辛烯基琥珀酸酐酯化后，其颗粒表面出现不同程度的凹陷和破裂，说明酯化反应发生在淀粉颗粒表面；产品的红外光谱在1718 cm-1和1554 cm-1处出现新的吸收峰，其中1718 cm-1处的吸收峰表明酯羰基的存在，说明分子中引入了新的官能团，1554 cm-1处出现的特征峰是缘于RCOO-不对称的伸缩振动；产品的起始糊化温度、峰值糊化温度、糊化结束温度和糊化热焓值降低，说明淀粉结晶结构的致密程度下降；随着产品取代度的增加，淀粉糊峰值粘度升高，出峰时间提前，糊化温度降低。

Abstract:

The granule morphology, structure, thermal property, and viscosity property of octenyl succinate anhydride (OSA) modified sweet potato starch were investigated by modern instrument analytical methods including scanning electron microscope(SEM), fourier transforms infrared (FTIR), differential scanning calorimeter (DSC), and rapid viscosity analyzer (RAV) with the comparison of the native sweet potato starch. Results showed that a certain dents and splits were observed on the surface of OSA sweet potato starch, indicating that the esterification occurred on the surface of starch granule. New absorption peaks were detected at 1718 cm-1 and 1554 cm-1 by FT-IR spectrum, the peak that at 1718 cm-1 suggested the formation of ester carbonyl groups, and another new peak appeared at 1554 cm-1 ascribed to the asymmetric stretching vibration of carboxylate (RCOO-). The onset transition temperature (To), peak transition temperature (Tp), completion transition temperature (Tc) and gelatinization enthalpy of OSA sweet potato starch were decreased, indicating that the crystallinity of starch was decreased. With the increased degree of substitution (DS), the peak viscosity of starch paste was increased, peak time was advanced, and pasting temperature was decreased.