【作者】 林丽菁；

【导师】 童张法；

【作者基本信息】 广西大学 ， 化学工艺， 2005， 硕士

【摘要】 淀粉磷酸酯是原淀粉与磷酸盐发生酯化反应而生成的一种淀粉衍生物。过去,使用较多的是低取代度(DS≈0.02)的淀粉磷酸酯。目前,较高取代度(DS>0.02)的淀粉磷酸酯广泛应用于造纸、纺织、食品等领域。因此,对高取代度淀粉磷酸酯的生产工艺、产品结构及性能进行研究,具有重大的意义。 首先,用混和正磷酸盐或三聚磷酸钠为酯化剂,干法制备高取代度木薯淀粉磷酸酯。设计单因素实验考察反应条件(酯化剂用量、反应温度、反应时间、反应pH和尿素用量)对产品取代度及反应效率的影响。实验表明干法制备高取代度木薯淀粉磷酸酯的适宜条件为:反应温度140℃～150℃,反应pH5.0,反应时间2h,尿素用量4～5%。通过调整磷酸盐的加入量,可以方便地获得取代度0.02～0.09的木薯淀粉磷酸酯,反应效率约为60%～70%。 然后,用红外光谱(FTIR)、扫描电镜(SEM)、X-射线衍射(XRD)、差示扫描量热分析(DSC)及淀粉-碘复合物吸收光谱分析对木薯淀粉磷酸酯的结构进行表征,并对产品糊的理化性质进行研究。结构分析表明:酯化反应虽在淀粉分子上增加了磷酸基团,但该基团的引入并不能在红外光谱上反映出来;酯化反应后,淀粉颗粒表面出现不同程度的凹陷和裂缝;酯化不仅发生在淀粉颗粒的无定型区,也发生在结晶更多还原

【Abstract】 Starch phosphate (SP) is one kind of starch derivative produced from esterification of starch and phosphate. SP with low degree of substitution(DS)(DS≠0.02) was usually applied in the past. Now SP with higher DS(DS>0.02) is widely used in paper-making, textile, food industry and so on. So the investigations about synthesis, structures and physicochemical properties of SP with high DS are becoming more and more important.Firstly, mixture of orthophosphate (MP) or sodium tripolophosphate (STP) was used as esterifying agent in preparation of cassava starch phosphaite by dry process. The effects of different reaction conditions on DS and reaction efficiency (RE) were testified by single factor experiments. The influence factors include amount of esterifying agent, reaction temperature, reaction time, reaction pH and amount of urea. Results show that the optimum reaction conditions for preparing SP with high DS by dry process as follows: the range of reaction temperature was 140~150℃, the reaction time was 2h, the pH was 5.0 and the range of urea amount was 4%~5%. By adjusting the amount of esterifying agent, SP with DS 0.02~ 0.09 can be prepared easily while RE is about 60%~ 70%.Secondly, the structures of cassava starch phosphate were characterized by infrared spectrum (FTIR), scanning electron microscopy (SEM), x-ray diffraction (XRD), differential scanning calorimetry (DSC) and analysis of starch-iodine compound absorption spectrum. Furthermore, its physicochemical properties were investigated. Structure analysis indicated that -PO4 groups were added in glucose units of starch but it can’t be manifested in the FTIR spectra. There were a certain of dents and splits on SP granules surface. Esterification of starch not only occurred in the amorphous region of starch granule, but also damaged its crystalline region. After esterification of starch, the pasting temperature will decrease and the pasting enthalpy get lower and the range of pasting temperature will get narrow. And partial starch chains were ruptured and partial helix structures of starch were destroyed. The experimental results of SP physicochemical properties indicated that cassava starch paste and SP paste were of the pseudoplastic characteristics. Viscosity of SP paste was relatively stable in high(95℃) or low(55℃) temperature. Transparency of SPpaste with DS ≤0.084 was higher than that of cassava starch. Retro gradation and freeze-thaw stability of SP paste were improved.Finally, the feasibility of preparation cassava starch phosphates by dry process was discussed. The costing and the economic balance about SP prodution and marcketing were evaluated.更多还原