黄芪水提取物吸湿模型的拟合

Fitting of moisture adsorption models for Astragali Radix aqueous extract

目的拟合黄芪水提取物吸湿模型。方法煎煮法制备水提取物,重量法绘制提取物的吸湿动力学曲线和吸附/解吸等温线,对吸湿数据进行拟合。以均方根误差(RMSE)、残差平方和(RSS)和决定系数(R2)为评价指标,优化拟合模型。结果吸湿动力学曲线的双指数模型,以及吸附/解吸等温线的Peleg模型为拟合效果最佳的2个模型(R2最接近于1,RMSE和RSS最接近于0)。其中,各吸附/解吸等温线都属于第Ⅱ种类型"S"等温线,而解吸等温线平衡含水率高于吸附等温线,故出现明显的滞后现象,并属于H3型。结论双指数模型和Peleg模型分别能较好地拟合黄芪水提取物的吸湿动力学曲线和吸附/解吸等温线。

AIM To fit the moisture adsorption models for Astragali Radix aqueous extract. METHODS For the aqueous extract prepared by decocting,the moisture adsorption kinetics curve and adsorption / desorption isotherms were drawn by gravimetry,and then the data on moisture adsorption were fitted. The fitted models were optimized according to evaluation indices of root mean square error（ RMSE）,residual sum of squares（ RSS） and coefficient of determination（ R-2）. RESULTS The double exponential model for moisture adsorption kinetics curve and Peleg model for adsorption / desorption isotherms were considered as the two best models with regard to their fitting effects（ R-2 values were the closest to 1,RMSE and RSS values were the closest to 0）. Among them,various adsorption / desorption isotherms all belonged to type II（ ＂S＂isotherm）,while the higher equilibrium moisture content of desorption isotherm than that of adsorption isotherm contributed to obvious type H3 hysteresis phenomenon. CONCLUSION Double exponential model and Peleg model can well fit the moisture adsorption kinetics curve and adsorption / desorption isotherms of Astragali Radix aqueous extract,respectively.