聚乙烯醇活性薄膜中紫薯花青素和纳米二氧化钛的释放动力学分析

Analysis on the release kinetics of purple potato anthocyanin and nano-TiO_2 from active poly-(vinyl alcohol) films

将紫薯花青素和纳米二氧化钛掺入聚乙烯醇中,通过溶液流延法制备聚乙烯醇活性薄膜。以紫薯花青素主要成分之一的矢车菊素衡量薄膜中紫薯花青素的释放规律,研究了聚乙烯醇活性薄膜中矢车菊素和纳米二氧化钛向含水食品模拟液、酸性食品模拟液、亲酯性食品模拟液和油性食品模拟液中的释放规律,并基于Fickian+一级动力学模型对试验数据进行拟合表征。研究结果表明:对比4种食品模拟液,聚乙烯醇活性薄膜中矢车菊素和纳米二氧化钛的扩散系数和释放比,在油性食品模拟液中最高,扩散系数分别达到5×10^(-11),1.29×10^(-13) cm^2/s,释放比分别达到0.966和0.357,然后依次为亲酯性食品模拟液和酸性食品模拟液,在含水食品模拟液中的扩散系数和释放比最低,扩散系数分别为1.34×10^(-11),0.85×10^(-13) cm^2/s,释放比分别降至0.25和0.121。聚乙烯醇活性薄膜中矢车菊素和纳米二氧化钛向4种食品模拟液中的释放规律能够用Fickian+一级动力学模型进行表征,且拟合精度R^2均达到0.98以上。通过Fickian+一级动力学模型拟合的4种食品模拟液中矢车菊素和纳米二氧化钛的释放曲线整体变化趋势相似,均呈先快速上升后逐渐平缓的趋势。

The purple potato anthocyanin and nano-titanium dioxide were incorporated into polyvinyl alcohol,and polyvinyl alcohol active films were prepared by solution casting method.In this paper,the release of purple potato anthocyanins from the film was measured by cyanidin,which was one of the main components of purple potato anthocyanins.The release of cyanidin and nano-titanium dioxide into aqueous food simulating liquid,acidic food simulating liquid,lipophilic food simulating liquid and oily food simulating liquid from polyvinyl alcohol active film was studied,the experimental data were fitted and characterized based on Fickian+first-order kinetic model.The results showed that the diffusion coefficient and release ratio of cyanidin and nano-titanium dioxide from the film to the oily food simulating liquids were the highest,the diffusion coefficient was 5 ×10^-11 cm^2/s and 1.29×10^-13 cm^2/s,the release ratio was 0.966 and 0.357,respectively.Then,the lipophilic food simulating liquid and the acidic food simulating liquid were followed,the aqueous food simulating liquid was the lowest,the diffusion coefficient was 1.34×10^-11 cm^2/s and 0.85×10^-13 cm^2/s,the release ratio was decreased to 0.25 and 0.121,respectively.The release law of cyanidin and nano-titanium dioxide into four food simulants from polyvinyl alcohol active films can be characterized by Fickian+ first-order kinetic model,and the fitting accuracy R^2 is above 0.98.The overall variation trend of the Fickian+first-order kinetic model release curve of the cyanidin and nano titanium dioxide in four food simulants was similar,and showing a rapid rise and then gradually flattening.In this paper,the Fickian+first-order kinetic model was used to study the release law of active substances from polyvinyl alcohol active films in these four food simulants with the changes of time,and provide a reference basis for the development of future release active films and the research on controlled-release technology.