聚乙烯醇薄膜中茶多酚向水中释放的不同动力学模型比较分析

Comparison of Different Kinetic Models for Tea Polyphenols Released from Poly-(vinyl alcohol) Films into Water

研究聚乙烯醇薄膜中茶多酚向水中释放的不同动力学模型表征。通过释放实验研究了薄膜中茶多酚向水中的释放规律,基于4种动力学模型对实验数据进行拟合表征,比较分析了不同模型的拟合效果。结果表明:茶多酚释放率随薄膜中茶多酚质量浓度的增加而降低。对比不同模型的拟合效果,Fickian模型和Fickian+一级动力学模型可以很好地模拟茶多酚的释放(R^2≥97.27),后者更优;Weibull模型的拟合效果较前两个模型差(R2≥85.21),但是该模型可以很好地模拟从释放开始到平衡初期茶多酚的释放(R^2≥92.20);短期释放模型的拟合效果较好(R^2≥91.32),但其扩散系数与由Fickian模型和Fickian+一级动力学模型得到的扩散系数相差较大。总的来看,Fickian+一级动力学模型模拟效果最好,Fickian模型次之,Weibull模型模拟从释放开始到平衡初期过程的效果较好,短期释放模型不适合用于模拟评估聚乙烯醇薄膜中茶多酚整个释放过程中的释放性能。

Different kinetic models describing tea polyphenols(TP)released from poly-(vinyl alcohol)(PVA)films into water were investigated.The release behavior of TP was studied through release experiments.The experimental data were fitted to four kinetic models and the goodness of fit of the models was analyzed.The results showed that the percentage of released TP from PVA films decreased with increasing TP content.The Fickian model and the Fickian+first-order kinetic model could simulate TP release well(R^2≥97.27),with the latter being more effective than the former.Although the Weibull model exhibited worse goodness of fit than the above two models(R^2≥85.21),it could simulate TP release well during the period from the beginning to the initial equilibrium stage(R^2≥92.20).The short-term release model showed good fitness(R^2≥91.32).However,its diffusion coefficient was different considerably from the value obtained by the Fickian model and the Fickian+first-order kinetic models.Among the four kinetic models,the fitness of the Fickian+first-order kinetic model was the best closely followed by the Fickian model.The Weibull model could simulate TP release behavior well during the period from the beginning to the initial equilibrium stage.The short-term release model was not suitable for simulating and evaluating TP release behavior from PVA films during the whole release process.