以三个品种苹果（水晶富士、嘎啦果、青苹果）为原料，通过体外模拟胃肠消化和有机溶剂提取方法提取苹果的生物活性物质，测定提取液的多酚、黄酮及抗氧化活性，分析这三者的变化规律和相关性。结果表明，模拟胃肠消化后，苹果的多酚、黄酮、抗氧化活性显著提高（P < 0.05），在胃肠消化1 h内多酚释放量达到最大值并保持稳定，胃消化阶段最大释放量多酚为消化前的1.36~1.76倍，肠消化为消化前的1.34~2.08倍。苹果多酚主要由游离态多酚组成，有机溶剂提取液的多酚含量高于模拟胃肠消化后提取液多酚（P < 0.05）。模拟胃消化阶段，多酚、黄酮、抗氧化活性之间存在显著正相关（r =0.74~0.99，P < 0.05），而肠消化阶段，抗氧化活性与多酚、黄酮的相关系数r = -0.47~0.47（P <0.05），相关性较低。模拟胃肠消化，可能引起多酚类物质的含量和结构的改变，从而导致多酚、黄酮、抗氧化活性的提高。

Three cultivars of apples (Fuji, Gala, and Granny Smith apples) were used as raw materials for the investigation. Bioactive substances were extracted by in vitro gastrointestinal digestion and organic solvent extraction method. The antioxidant activity, as well as polyphenol and flavonoid contents in the extract, were determined, and patterns in the changes and correlations among these three were analyzed. The results showed that after simulated gastrointestinal digestion, antioxidant activity and polyphenol and flavonoid contents of apples increased significantly (P < 0.05). The amount of released polyphenol reached a maximum level and remained stable during the one-hour gastrointestinal digestion. During gastric digestion, the maximum amount of released polyphenol was 1.36~1.76 times higher than that before gastric digestion. During intestinal digestion, the maximum amount of released polyphenol was 1.34~2.08 times higher than that before intestinal digestion. Apple polyphenols are mainly composed of free polyphenols, and the content of polyphenols in the organic solvent extract was more than that after the simulation of gastrointestinal digestion (P < 0.05). At the simulated gastric digestion phase, a strong correlation (r = 0.74~0.99，P < 0.05) was noted among antioxidant activity and polyphenol and flavonoid contents. However, at the intestinal digestion phase, the correlation among antioxidant activity and flavonoid and polyphenol contents was low (r = -0.47~0.47, P < 0.05). Simulating gastrointestinal digestion may cause changes in the content and structure of polyphenols, leading to increases in antioxidant activity and polyphenol and flavonoid contents.

广东省省国际合作项目（2012B050600031）；深圳市科技计划项目（JCYJ20130331151512026）