熟化红薯热风干燥特性及数学模型适用性

Drying characteristics and mathematical modeling ofhot air drying of cooked sweet potatoes

为了为红薯干热风干燥工业化提供理论基础,该文研究了不同温度(60、70、80℃)、风速(0.8、1.2、1.6m/s)和厚度(0.6、0.9、1.2cm)条件下红薯的热风干燥特性。比较了12种数学模型在熟化红薯热风干燥中的适用性,结果表明WangandSingh模型的拟合程度最高,R2值、χ2和RMSE值分别为0.998、0.000168和0.0117。计算了不同干燥条件下的有效水分扩散系数Deff和活化能Ea,有效水分扩散系数Deff随着干燥温度、风速和物料厚度的增加而变大,干燥活化能Ea为40.103kJ/mol,可为其干燥工艺的控制提供技术依据。

To provide a theoretical foundation for the industrial production of dried sweet potato,the hot air drying characteristics of sweet potato slices were examined under different temperatures（60,70 and 80℃）,air velocities（0.8,1.2 and 1.6 m/s） and slice thickness（0.6,0.9 and 1.2 cm）,respectively.The drying data were fitted to different semi-theoretical models,such as Newton,Page,modi？ed Page,Henderson and Pabis,Logarithmic,two-term,Wang and Singh,Thomson,diffusion approach,Werma,et al.,modi？ed Henderson and Pabis,and two term exponential models.As a result,the Wang and Singh model gave better predictions than other models with the decision coefficient（R2） of 0.998,chi-square（χ2） of 0.000168 and root mean square error（RMSE） of 0.0117.The effective moisture diffusivity and activation energy were also computed.The results indicated that Deff increased with the increasing of drying temperature,air velocity and material thickness,and activation energy of drying was 40.103 kJ/mol.The results can provide technical bases for the control of drying process of sweet potato.