大野芋薄层干燥特性及收缩动力学模型研究

Studies on Drying Characteristics and Shrinkage Kinetics Modelling of Colocasia gigantea Slices during Thin Layer Drying

为提高大野芋的品质,缩短干燥时间,控制收缩,研究大野芋在薄层干燥中不同温度(50,60,70,80℃)和切片厚度(4,7,10,13 mm)下的干燥曲线和体积收缩变化规律。研究表明:干燥温度和切片厚度对大野芋干燥时间有显著影响,大野芋薄层干燥水分有效扩散系数在3.2087×10-9~1.5010×10-8m2/s之间;干燥温度和切片厚度均对大野芋收缩率有显著影响,采用较低的干燥温度和较厚的切片厚度能够提高收缩率,减少收缩;Weibull分布函数能够很好地描述大野芋的收缩动力学曲线,拟合效果最优。通过阿伦尼乌斯公式计算得到大野芋干燥活化能和收缩活化能分别为35.33 k J/mol和57.19 k J/mol。本研究结果为大野芋在干燥加工中水分迁移和体积收缩变化的预测、调控提供理论依据和技术支持。

The aim of this study was to improve the quality, shorten the drying time and control the shrinkage of Colocasia gigantea（CG） during the drying process. The drying curves and volume shrinkage kinetics models of CG slices were investigated under different drying temperatures（50, 60, 70, 80 ℃） and slice thickness（4, 7, 10, 13 mm） by hot-air thin layer drying. The results demonstrated that drying temperature and slice thickness showed a significant impact on drying time, and the moisture effective diffusivity was between 3.2087×10^-9-1.5010×10^-8 m^2/s. The shrinkage ratio was apparently influenced by drying temperature and slice thickness, and it would have a higher shrinkage ratio under lower drying temperature and thicker slice thickness. The Weibull distribution could well describe the shrinkage curves, for the shrinkage ratio vs. drying time profiled of the model showed high correlation coefficient（R2）, and low root mean squared error（RMSE） and chi-squared（χ2）. The drying activation energy and shrinkage activation energy of CG slices was 35.33 kJ/mol and 57.19 kJ/mol, respectively. The results will provide a reference for the prediction and regulation moisture migration and shrinkage of CG slices during process.