稻谷热变性温度的试验

The Experimental Research on Paddy Thermal Denaturation

用差热分析（ＤＴＡ）方法，测得了稻谷在不同含水量状态下的差热分析曲线，湿基含水量为３０％ 、２４％ 、１８％ 时稻谷的热变性温度分别为３７．８℃、４９．２℃、５８．７℃。回归分析得出了稻谷含水量与热变性温度的关系方程，证明稻谷含水量越高，允许受热极限温度越低。

In this paper, the authors applied the differential thermal analysis (DTA) to study thermal behavior of starch in paddy. DTA curve being different moisture were measured by DTA apparatus. Thermal denaturation temperature (TDT) corresponding with respective moisture (wet basis) 30%, 24%, 18% is 37 8℃, 49 2℃, 58 7℃. The regression equation that reflects the relation between paddy moisture and TDT is θ lim =90 4-1 7 M . The higher is the moisture of paddy, the lower is its TDT. The upper limit temperature for paddy drying can be determined by the equation. The paddy denaturation reason is that the starch of paddy is gelatinating in endothermic reaction. The rice taste of denaturation paddy is bad.