柑橘在体外模拟胃肠消化过程中总多酚、总黄酮及总抗氧化活性的变化规律

通过体外模拟胃肠消化法模拟柑橘在胃肠道的消化过程，测定模拟胃肠消化过程中总多酚、总黄酮的释放量及总抗氧化活性的变化规律。结果显示，柑橘多酚主要是游离酚，有机化学提取法释放的多酚高于模拟胃肠消化法。模拟胃消化3 h后，与消化0 h相比，宽皮柑、脐橙和金橘的多酚最大释放量是其1.02、0.93、1.21 倍，黄酮最大释放量是其1.46、2.37、2.16 倍，最大抗氧化活性是其1.10、1.23、1.62 倍。体外模拟肠消化4 h后，与胃消化0 h和肠消化0 h相比，宽皮柑、脐橙和金橘的多酚释放量分别为其0.99、0.80、1.29 倍和91%、81%、90%，黄酮的最大释放量分别为其73%、39%、64%和51%、17%、39%，最大抗氧化活性分别为其1.67、1.09、1.76 倍和1.31、0.88、1.22 倍。这表明柑橘在模拟胃肠消化过程中，胃蛋白酶、胰酶、胆汁及胃酸均可以促进抗氧化活性物质释放。

Changes in Total Polyphenols,Total Flavonoids and Antioxidant Activity of Citrus during in Vitro Gastrointestinal Digestion Process

The changes in the release of total polyphenols and total flavonoids, as well as antioxidant activity in terms
of oxygen radical absorbance capacity (ORAC) of citrus (Citrus reticulata, Navel orange and kumquat) during in vitro
simulated gastrointestinal digestion were determined. The results showed that the citrus polyphenols were mainly free
phenols, and that the release of polyphenols via organic solvent extraction method was higher than that from simulated
gastrointestinal digestion. Specifically, the release of polyphenols from Citrus reticulata, Navel orange and kumquat at the
third hour of simulated gastric digestion were 1.02-, 0.93- and 1.21-fold higher than those at 0 h, the release of flavonoids
were 1.46, 2.37 and 2.16 times higher than that at 0 h, and ORAC values were raised 1.10, 1.23 and 1.62 times after 3 h
digestion for the three citrus species, respectively. In addition, after 4 h of simulated intestinal digestion, preceded by 2 h
simulated gastric digestion, the release of polyphenols from Citrus reticulata, Navel orange and kumquat were 0.99-, 0.80-
and 1.29-fold higher than those before gastric digestion, and 0.91-, 0.81- and 0.90-fold higher than those before intestinal
digestion; the release of flavonoids were increased by 73%, 39% and 64% during the gastrointestinal digestion period (namely
2 h gastric digestion followed by 4 h intestinal digestion) and by 51%, 17% and 39% during the intestinal digestion, with
an increase in ORAC values by 1.67, 1.09 and 1.76 times during the whole digestion period, and 1.31, 0.88 and 1.22 times
during the intestinal digestion, respectively. The finding in this study indicate that pepsin, pancreatin, bile and gastric acid
can promote the release of antioxidant substances from citrus during simulated gastrointestinal digestion.