大豆水分解吸-吸附等温线拟合模型

Water Desorption and Adsorption Isotherms of Soybeans

为给在干燥、贮藏及运输过程中保证大豆的品质提供理论依据,实验测定了大豆在室温(25℃)条件下的水分解吸-吸附等温线。采用非线性回归分析,应用常见的5种模型Oswin、Halsey、Hendenson、GAB、Chung-Pfost对大豆在室温条件下测得的水分进行解吸-吸附等温线拟合分析,以确定最佳拟合模型及其参数。结果表明:大豆的解吸等温线属于第Ⅱ种类型;吸附等温线属于第Ⅲ种类型;在整个水分活度范围内,大豆的解吸-吸附等温线均存在着滞后现象;最佳的解吸-吸附等温线拟合方程都是Oswin模型,它们的决定系数均高于0.993;Oswin模型拟合大豆解吸等温线的参数A和B分别为0.075和0.500,吸附等温线的参数A和B分别为0.075和0.498。

The desorption and adsorption isotherms of soybeans were determined at room temperature(25 ℃).Five commonly used models including Oswin,GAB,Halsey,Hendenson,and Chung-Pfost were applied to fit the experimental data and to determine the best model as well as its parameters with non-linear regression analysis.The results indicated that the desorption isotherm of soybeans belonged to type II,but the adsorption isotherm of soybean belonged to type III.Within the whole scope of water activity,there was a hysteresis loop for soybean desorption-adsorption isotherms.The Oswin model demonstrated the best fitting model for soybean desorption-adsorption isotherms with coefficient of determination r2 > 0.993.The parameters A and B of Oswin model for desorption were 0.075 and 0.500,and those for adsorption were 0.075 and 0.498,respectively.