稻谷热风、微波干燥品质与玻璃化转变研究

以函数拟合、近红外检测及发芽率测定,研究稻谷热风、微波干燥的去水性能及其蛋白质、直链淀粉含量与出芽品质;结合TG/DSC测试,探讨2种热源干燥稻谷的玻璃化转变对其干燥后品质的影响。结果表明:以对数函数拟合稻谷热风、微波干燥去水性能的准确度高;经2种热源干燥稻谷的蛋白质、淀粉含量过程差异不显著;但热风干燥稻谷初期蛋白质含量差异明显。鲜稻谷发芽率显著低于其经热风、微波干燥后的发芽率,三者分别为0.65±0.19、0.93±0.03、0.77±0.02。随含水率降低,经热风、微波干燥稻谷的热重损失与热流则呈不同趋势变化,二者中点温度均减小,综合影响干谷品质。

Effect of Drying Methods on Quality and Glass Transition Temperature of Rice

The dynamic of rice moisture content during hot air and microwave drying was measured and analyzed. The dynamic property of protein, amylose content and germination ratio of rice were analyzed by near infrared detection and germination observation. Furthermore, the influence of drying method on rice quality was measured by glass transition temperature which was got from the analysis of TG/DSC. Results showed that the fitting accuracy of logarithmic model was higher than exponential model during the process of rice dehydration by both drying methods, and the difference in protein and starch content of dried rice was not significant. However, there were significant differences in protein content between fresh and dried rice by hot air drying. The germination ratio of rice dried by hot air and microwave was much higher than fresh ones, which was 0.93±0.03, 0.77±0.02 and 0.65±0.19, respectively. As the rice moisture content decreased, the mass loss and heat flux of dried rice showed different changing trend and the glass transition temperature decreased as well. All of them had effect on the quality of dried rice. The results could be a reference for improving efficiency and quality during the process of grain drying.