大米淀粉磷酸酯的制备及其理化性质研究

为合理地利用丰富的大米淀粉资源,以大米淀粉为原料,尿素为催化剂,正磷酸盐为酯化剂,采用响应曲面法确定了制备大米淀粉磷酸酯的最佳工艺条件:磷酸盐用量为淀粉质量的46.61%,催化剂用量为淀粉质量的4.03%,反应pH为5.5,反应时间为4.6 h。在此条件下制得的磷酸酯淀粉的取代度为0.020 34。并用扫描电镜(SEM)对反应前后淀粉颗粒的形貌进行了观察,结果表明,磷酸酯化后,部分淀粉颗粒受到侵蚀。同时研究了大米淀粉磷酸酯的理化性质,包括溶解度、膨胀度、糊化特性、凝沉性、冻融稳定性及黏弹特性。结果表明,相对于原淀粉,磷酸酯淀粉的溶解度、膨胀度、黏度有所提高,糊化温度、凝沉性、凝胶硬度和强度则下降。

Synthesis of rice starch phosphate and study of physicochemical properties

Response surface methodology was employed to optimize conditions for preparation of rice phosphate starch. The optimal reaction conditions are determined to be reaction time of 4.6 h, pH 5.5, concentration of orthophosphate salts of 46.61% of the starch mass and the amount of (NH)₂CO of 4.03% of the starch mass. The morphology was observed using a scanning electron microscope (SEM). The SEM results indicated that granules surface of starch phosphate had been eroded. Properties of rice phosphate starch, including solubility, swelling degree, pasting properties, retrogradation, freeze-thaw stability and viscoelastic properties of starch paste, were systematically studied. The results showed an increase of the solubility, swelling degree and viscosity, and a decrease of the pasting temperature, retrogradation, pasting hardness and strength.