为研究青豆种子在吸附和解吸过程中热量的变化规律,应用非线性回归方法确定了青豆种子等温线最优模型,采用水分活度等量吸附热模型方法,计算了青豆种子平衡含水率在5%~32%(干基)范围内的热动力参数———净等量吸附热与解吸热。结果表明:Halsey模型为青豆种子等温线最优模型,净等量吸附与解吸热分别为105.2~1 865.4 kJ.kg-1和111.6~1 939.0 kJ.kg-1,且随平衡含水率的增加而减少,等量解吸热高于等量吸附热。通过水分活度等量吸附热模型求解的数值在合理的范围之内。
In order to investigate the change regularity of heat in adsorption and desorption process of green soybean seeds,a most suitable model of sorption isotherms for green soybean seeds was estimated by using nonlinear regression method.The thermodynamic parameters including net isosteric heat of adsorption and desorption calculated by using water activity isosteric sorption heat model with equilibrium moisture content between 5% and 32%(dry basis).Results indicated that Halsey model was the optimization isotherm model of green soybean seeds,and the net isosteric heat of adsorption and desorption were 105.2-1 865.4 kJ·kg-1 and 111.6-1 939.0 kJ·kg-1,respectively,which decreased with the increase of equilibrium moisture content.The net isosteric heat of desorption was higher than that of adsorption.The values calculated by the water activity isosteric sorption heat model were in a reasonable range.