Authors

Abstract

To improve the quality of paddy, reduce post-production losses, and ensure processing efficiency, this paper proposes a variable-temperature drying process based on the glass transition phenomenon, using the relationship between paddy moisture content and glass transition temperature. An optical three-dimensional scanning method was employed to obtain the paddy grain particle model. Subsequently, a heat and mass transfer model for paddy was constructed to analyze the temperature distribution and moisture migration behavior during drying. Experiments were conducted using a constant temperature of 40 ℃ and heating amplitudes of 5 ℃, 10 ℃, and 15 ℃ to investigate the drying characteristics and quality evolution of paddy. The simulation results showed that the average errors for moisture content and temperature were 1.58% and 2.66%, respectively. Compared with constant temperature drying at 40 ℃, the variable-temperature drying with heating amplitudes of 5 ℃, 10℃, and 15℃ reduced the drying time by 19, 58, and 63 minutes, respectively. Among the tested conditions, the 5 °C heating amplitude yielded the best results, with a crack increase rate of only 2.5% and a head rice yield of 68.3%. These findings offer valuable insights for understanding the mechanism of variable-temperature drying and for optimizing the drying process of paddy.

Abstract in Chinese

为提高稻谷品质、减少产后损失、保障加工质量等方面，本文通过稻谷含水率与玻璃化转变温度之间的关系，提出基于玻璃化转变的变温干燥工艺。采用光学三维扫描方法获取稻谷颗粒模型，再次基础上构建稻谷传热传质模型解析稻谷温度、水分的迁移规律。以40℃恒温及5℃、10℃、15℃的加热幅度为变量，开展试验探究稻谷干燥特性及其品质变化趋势。研究结果显示，模型模拟含水率的平均误差为1.58%，温度的平均误差为2.66%。与40℃恒温干燥相比，5℃、10℃和15℃升温幅度分别使干燥时间缩短了19分钟、58分钟和63分钟。其中，5℃升温幅度的干燥工艺裂纹增率仅为2.5%，整精米率达到68.3%。研究结果为变温干燥机理及工艺优化提供参考。