红枣薄层干制数学模型研究

以电热鼓风恒温干燥箱在不同温度下干燥红枣，研究红枣的干燥特性，选取7个常用的薄层干燥数学模型，并采用非线性回归法对实验数据进行拟合，从而建立红枣薄层干燥数学模型。结果表明：红枣的干燥过程可分为2个阶段，加速期和降速期，没有出现恒速期；比较各模型的相关系数(R2)、均方根误差(RMSE)和卡方值(χ2)，结果Page模型拟合效果最好，R2为0.99921，χ2为0.0088687，RMSE为0.0082514，并考察了热风温度对Page模型常数k和n的影响。经验证，该模型能很好地描述红枣热风恒温干燥过程水分比的变化规律，可用于预测红枣的干燥过程。

Mathematical Modeling of Thin-layer Drying of Red Dates (Ziziphus jujuba Mill)

In order to explore the drying regularity of red dates and provide a theoretical foundation for the drying of red dates, the drying characteristics of red dates were evaluated in a laboratory scale dryer. The drying experiments were carried out at 50, 60 ℃ and 70 ℃ at a constant air velocity. Seven commonly used thin-layer drying mathematical models were selected and used to fit the experimental data using non-linear regression analysis for establishing a suitable mathematical model that describes the drying of red dates. The results indicated that the drying process involved two stages, acceleration phase and deceleration phase, without a constant-rate phase. The performance of different drying models was investigated by comparing their coefficients (R2), chi-square values (χ2) and root mean square errors (RMSE). Among these models, the Page model was the most suitable model for describing the drying curve of red dates with a R2 of 0.99921, χ2 of 0.0088687 and RMSE of 0.0082514. The effect of drying air temperature on the rate constant and coefficient of the Page model was also explored. Therefore, this model can adequately describe the change regulation of water content according to the comparison of experimental values and predicted values.