大米淀粉及其磷酸酯的理化性质研究

对大米淀粉进行酯化,通过改变温度得到不同取代度的大米淀粉磷酸酯,使用扫描电子显微镜、质构仪、快速黏度分析仪、流变仪对大米淀粉及其不同取代度的淀粉磷酸酯的理化性质进行了测定。结果显示:大米磷酸酯淀粉的硬度、回复性、胶性和咀嚼性要低于大米原淀粉,凝聚性和黏着性要高于原淀粉,取代度越大硬度、回复性、胶性和咀嚼性越小,凝聚性和黏着性越大;大米淀粉磷酸酯的开始糊化温度要小于大米原淀粉,峰值黏度、最低黏度、最终黏度、崩解值、消减值要小于大米原淀粉,取代度增大,开始糊化温度降低,峰值黏度、最低黏度、最终黏度、崩解值、消减值增大。大米淀粉经过磷酸酯变性后,黏度增加了,不易回生,稳定性加强了,凝沉性减弱了,且取代度越高,这些性质越明显;大米淀粉磷酸酯和大米淀粉属于剪切稀化流体,在相同剪切速率下,取代度越大的大米淀粉磷酸酯表观黏度越大。

Study on Preparation and Physicochemical Properties of Rice Starch and its Phosphate Ester

Esterfying the starch phosphste to different degrees of substitution,the esterification reaction may be gotten for changing the temperature.The preparation and physicochemical properties of Rice Starch and its Phosphate Ester with different degrees of substitution(DS) were determined using scanning electron microscopy,texture analyzer,rapid viscosity analyzer(RVA) and rheometer.The results were as follows: the hardness,recovery,colloidal and chewing of rice starch phosphate ester were less than those of rice starch,but the cohesion and adhesion were higher than those of rice starch.With the increase in the degree of DS,the hardness,recovery,colloidal and chewing of rice starch phosphate este reduced,and the cohesion and adhesion of the increase with the degree of DS were increased;the gelatinization temperature of the rice starch phosphate ester was less than that of rice starch,and the values of peak viscosity,minimum viscosity,final viscosity,and breakdown and absolute values were less than those of rice starch;with the increase in the degree of DS,the gelatinization temperature of the rice starch phosphate ester was reduced and the values of peak viscosity,minimum viscosity,final viscosity and breakdown and absolute values were increased.Through esterification,the viscosity of the rice starch was increased,it was not easy for retrogradation,its stability was increased and its retrogradation was weakened.The higher the degree of substitution was,the more obvious these natures became.Rice starch and its phosphate belonged to shear-thinning fluid.At the same shear rate,the degree of substitution was higher and the viscosity was more apparent.