直链淀粉、蛋白质及脂类对大米粉热特性的影响

利用差示扫描量热仪(DSC)分别对籼米、粳米、泰国香米及糯米米粉热特性作了研究。实验结果表明:直链淀粉、蛋白质及脂类对米粉糊化熔点、峰值、糊化终点温度及糊化焓变有重要影响。直链淀粉显著影响大米米粉的糊化熔点、峰值和终点温度,高直链淀粉含量的大米米粉的糊化熔点、峰值和终点温度均高于中、低及糯米米粉;高直链淀粉含量的大米蒸煮性差、能耗高、蒸煮时间长,中、低直链淀粉含量的大米蒸煮性好、能耗少、蒸煮时间短。米粉中的蛋白质可能起到升高米粉糊化熔点、峰值及终点温度的作用;大米蛋白质含量越高,大米蒸煮性越差、能耗越高、蒸煮时间越长。米粉中的脂类对米粉热特性的影响较复杂,脂类可能起到降低糊化熔点糊化焓变的效果;大米中脂类含量越高,大米蒸煮性好、能耗少、蒸煮时间短。

Effects of Amylose, Protein and Lipid on the Thermal Properties of Rice Flour

The purpose of this study is to evaluate the thermal properties of rice flour from Indica rice, Japonica rice, Thai rice and Waxy rice by the method of differential scanning calorimeter (DSC).The results indicated that amylose, protein and lipid had significantly influence on the thermal properties of rice flour. The amylose content influence the onset, peak and end temperature of rice flour; and the onset, peak and end temperature of amylose riched rice flour was higher than medium, low and waxy rice flour; the rice with high amylose content had a bad cooking properties, high energy cost, long cooking time. The protein in rice flour maybe increase the onset, peak and end temperature of rice flour, and the higher protein content of rice, the worse cooking properties, higher energy cost and longer cooking time. The lipid maybe decrease the onset and enthalpy of rice flour, and the higher lipid content of rice, the better cooking properties, lower energy cost and less cooking time.