糖渍加应子的热风干燥特性及其表达模型

Characteristics of hot air drying of candied prunes and representation model

该文探讨了糖渍加应子样品在不同温度下热风干燥特性,通过建立数学模型,预测不同热风干燥过程加应子水分变化特性。干燥特性试验表明,加应子热风干燥是内部水分扩散控制的降速干燥过程,40～80℃范围内,温度对干燥速率有显著影响(P<0.05),温度越高,干燥速率越快,前2h,40℃时,干燥速率从3.52×10-2g/(g·h)降至2.03×10-2g/(g·h),降低了42.33%,80℃时,干燥速率由14.64×10-2g/(g·h)降至4.22×10-2g/(g·h),降低了71.17%;80～100℃范围内,样品表面出现结壳硬化现象,温度对干燥速率影响减弱(P>0.05)。结果表明,Page模型适合对加应子干燥过程进行描述和预测;Page模型变形求导得出加应子干燥速率模型,模型拟合度高,可为其干燥工艺的控制提供技术依据。

The drying characteristics of candied prunes at different hot air drying temperatures were investigated, and the moisture content of the prunes in different hot air drying could be predicted by establishing the mathematical models. The results showed that drying process of prunes occurred in the falling rate period, and the moisture transfer was controlled by internal diffusion. The drying rate was significantly influenced by temperature at the range of 40-80℃ （P〈0.05）. The drying rate decreased by 42.33% from 3.52× 10^-2 g/（g-h） to 2.03× 10^-2 g/（g.h） at 40℃ while the drying rate decreased by 71.17% form 14.64×10^-2 g/（g.h） to 4.22×10^-2 g/（g-h） at 80℃ during the drying period of 2 h. And temperature range from 80-100℃ showed lower influence on drying rate （P〉0.05） due to the case hardening effect. Modeling study indicated that Page equation could be suitable to describe the drying process of prunes according to the coefficients of determination （R2,X2）, and good agreement was found when random experimental data was compared with equation prediction. Drying rate equation calculated by the Page equation had good coincidence with experimental study. The results can provide technical bases for the control of drying technology.