无核白葡萄箱式热风干燥特性及干燥模型研究

摘要

Analysed the drying characteristics of white seedless grape under the conditions of air temperatures(30~45 ℃) and air velocity(0.5~2 m/s),and obtained the available moisture diffusion coeffi-cient and drying activation energy.Finally, non-linear regression analysis was used to develop four common agricultural thin layer-drying models based on the data, and these models were evaluated by coefficient of determination (R2), root mean squared error (RMSE) and chisquare value (χ2).Results: The available moisture diffusion coefficient were rising with the growth of air temperature and air velocity.The drying activation energy (Ea) is calculated to be 22.95 kJ/mol according to Arrhenius formula.According to the statistical parameters from four kinds of models, such as determination (R2), chisquare value (χ2) and root mean squared error (RMSE), the Parabolic model can well predict the moisture change law during drying process of white seedless grape.The results could provide a theoretical basis for white seedless grape drying production.%分析热风温度(30~45 ℃)、热风风速(0.5~2 m/s)等因素对无核白葡萄干燥特性的影响,计算不同条件下水分有效扩散系数(Deff)及干燥活化能(Ea),再采用4种薄层干燥模型对不同试验条件进行非线性拟合,并比较不同条件的R2、RMSE和χ2值.结果表明:在干燥过程中,随着干燥温度及风速的升高,Deff也随之升高,利用阿伦尼乌斯公式计算出无核白葡萄的干燥活化能为22.95 kJ/mol.通过4种模型的R2、RMSE和χ2值比较,Parabolic模型的拟合结果最好,最能描述葡萄干燥过程中水分比的变化规律,可为无核白葡萄干燥生产提供理论依据.