改性桔皮膳食纤维吸附茶多酚的条件优化及其体外模拟消化稳定性研究

【目的】开展改性桔皮膳食纤维对茶多酚的吸附条件优化及其复合物在模拟消化环境的稳定性研究，为促进茶多酚在健康食品中的应用提供技术支撑。【方法】采用动态高压微射流技术 （DHPM）改性的桔皮膳食纤维对茶多酚进行吸附，研究温度、时间、茶多酚浓度和pH对吸附量的影响，采用响应面法优化吸附条件，并建立模拟胃肠消化模型，考察膳食纤维—茶多酚复合物的消化稳定性。【结果】改性桔皮膳食纤维对茶多酚吸附量与温度呈负相关；随着时间的延长，茶多酚吸附量经历快速提高阶段后趋于平衡， 60 min时吸附量基本达到平衡；茶多酚浓度增至3.0 mg/mL时，其吸附量趋于饱和；溶液pH为7.0时，茶多酚吸附量达最大值。响应面试验结果表明，各因素对茶多酚吸附量的影响程度排序为温度>时间>茶多酚浓度>pH，且温度与时间、温度与茶多酚浓度的交互作用对茶多酚吸附量有显著影响（P<0.05，下同）。改性桔皮膳食纤维吸附茶多酚条件优化为:温度5 ℃，时间61 min，茶多酚浓度3.9 mg/mL， pH 7.0，在此条件下，茶多酚吸附量为54.26 mg/g，与模型理论值（54.46 mg/g）接近。体外模拟消化试验结果显示，改性桔皮膳食纤维—茶多酚复合物经模拟胃和肠道消化环境后，茶多酚保留率分别达92.07%和69.73%，显著高于纯茶多酚的保留率 （84.17%和47.29%）。【结论】改性桔皮膳食纤维可作为茶多酚的天然保护载体，通过吸附结合形成复合物，显著提高茶多酚在胃肠消化环境中的稳定性。

Optimization of adsorption conditions of tea polyphenols by modified citrus peel dietary fiber and its in vitro simulated digestion stability

【Objective】 The optimization of adsorption condition of tea polyphenols by modified citrus peel dietary fiber and the stability of its complex in a simulated digestive environment was explored with the aim of providing technical support for the application of tea polyphenols in healthy food.【Method】 Citrus peel dietary fiber modified using dynamic high pressure microfluidization（DHPM）was adopted to adsorb tea polyphenols to investigate the effects of temperature，time，tea polyphenol concentration and pH on the adsorption capacity.Response surface methodology was applied to optimize the adsorption conditions and a simulated gastrointestinal digestion model was established to investigate the digestive stability of dietary fiber-tea polyphenol complex.【Result】 The adsorption of tea polyphenols by modified citrus peel dietary fiber was negatively correlated with temperature and the amount of tea polyphenols adsorbed rapidly tended towards reach equilibrium over 60 min and was maximal at pH 7.0.Moreover，tea polyphenols adsorbed reached saturation when the concentration of tea polyphenols was increased to 3.0 mg/mL.The results of the response surface tests revealed that temperature had the greatest effect on the adsorption of tea polyphenols，followed by time，tea polyphenol concentration and pH，and the interactions of temperature and time，and temperature and tea polyphenol concentration exhibited significant effects on the adsorption of tea polyphenols（P<0.05，the same below）.The adsorption condition of tea polyphenols by modified citrus peel dietary fiber were optimized at a temperature of 5℃，a time of 61 min，tea polyphenol concentration of 3.9 mg/mL and a pH of 7.0.Under these conditions，the adsorption amount of tea polyphenols by modified citrus peel dietary fiber was 54.26 mg/g，which was close to the model theoretical value（54.46 mg/g）.The in vitro gastric and intestinal digestion tests demonstrated that the modified citrus peel dietary fiber-tea polyphenol complex possessed a tea polyphenol retention rate of 92.07% and 69.73%，respectively which were significantly higher than those of pure tea polyphenols（84.17% and 47.29%）.【Conclusion】As modified citrus peel dietary fiber can form a complex by adsorption and binding to improve the stability of tea polyphenols in the gastrointestinal digestion environment，it can be used as a natural protective carrier of tea polyphenols.