胡萝卜真空干燥特性及动力学

探究胡萝卜真空干燥过程中系统压力和温度对胡萝卜干燥特性的影响。结果表明:在同一系统压力下, 温度越高, 干燥速率越快;在同一干燥温度下, 系统压力越小, 干燥速率越快。通过应用Fick扩散定律描述胡萝卜的水分迁移规律, 在研究的温度范围内其有效水分扩散系数在6.717~18.594×10^-10之间变化。根据Arrhenius方程得到胡萝卜厚度为4和6mm的活化能分别为31.46和33.06 k J/mol。通过非线性回归方法将MR与五个薄层干燥模型进行拟合, 参照评价指标R²、RMSE及χ²等, 对多个模型进行综合分析, 其中Midilli and Kucuk模型显示出更好的拟合效果。

Vacuum Drying Characteristics and Kinetics of Carrot Slices

The effect of the pressure and drying temperature on the drying characteristics of carrotslices was investigated.The results show that the drying-rate significantly depends on the pressure and drying temperature.For example, at a fixed pressure, the drying-rate increased with an increase of the temperature; and at a given temperature, the dryingrate increased with a decrease of the pressure.Fick's diffusion law well describes the moisture diffusion of carrot slices, and the effective moisture diffusion coefficient varied from 6.717 × 10^-10 to 18.594 × 10^-10 inthe temperature of interest.The activation energies of the carrot slices, 4 mm and 6 mm in thickness, were estimated with Arrhenius equation to be 31.46 and 33.06 k J/mol, respectively.Among the five thin-layer low temperature drying models available for data fitting in the non-linear regression method, Midilli and Kucuk model best fited the carrot slices drying.