绿茶、橘皮、大豆中酚类物质体外消化前后稳定性及抗氧化活性的研究

谢乐怡; 张兵; 李红艳

doi:10.13386/j.issn1002-0306.2021110224

绿茶、橘皮、大豆中酚类物质体外消化前后稳定性及抗氧化活性的研究

Study on the Stability and Antioxidant Activity of Phenolics in Green Tea, Citrus Peel and Soybean before and after in Vitro Digestion

摘要

摘要: 本研究以富含3类代表性酚类化合物（黄烷醇、黄烷酮和异黄酮）的3种食物（绿茶、橘皮、大豆）作为原料，模拟其在人体口胃肠中的体外消化过程。采用高效液相色谱-二极管阵列检测器/电喷雾-四极杆-飞行时间串联质谱检测器（HPLC-DAD/ESI-Q-TOF-MS）检测体外消化前后酚类化合物的种类及含量变化，同时测定不同消化阶段总酚含量（TPC）、总黄酮含量（TFC）以及抗氧化活性（DPPH、ABTS、FRAP、ORAC）的变化。结果表明，绿茶提取物中检测出4种酚类化合物（表没食子儿茶素、(+)-儿茶素、表没食子儿茶素没食子酸酯和表儿茶素没食子酸酯），大豆提取物中检测出4种酚类化合物（大豆苷、染料木苷、大豆苷元和染料木素），橘皮提取物中检测出2种酚类化合物（柚皮苷和橙皮苷）；三种食物提取物中，经过体外消化后，绿茶提取物中的酚类化合物最不稳定，除(+)-儿茶素外，其余3种酚类物质几乎降解完全，损失率均达95%以上。绿茶、橘皮、大豆提取物的TPC在胃消化阶段显著升高（P<0.05），在肠消化阶段显著降低（P<0.05）。绿茶提取物TFC在口腔和胃消化阶段显著升高（P<0.05），在肠消化阶段显著降低（P<0.05）。橘皮、大豆提取物TFC与TPC变化趋势一致。绿茶提取物的四种抗氧化活性经胃肠消化后呈先升高再降低的趋势。大豆提取液体外消化前后ABTS、FRAP抗氧化活性在口腔阶段显著降低（P<0.05），DPPH、ORAC抗氧化活性在口腔、胃消化阶段显著升高（P<0.05），在肠消化阶段显著降低（P<0.05）。橘皮提取液ORAC抗氧化活性在肠消化阶段显著升高（P<0.05），ABTS、FRAP抗氧化活性在体外消化阶段均表现出和总酚含量变化一致的趋势。

Abstract: In this study, three kinds of foods (green tea, citrus peel and soybean) rich in three representative phenolic compounds (flavanols, flavanones and isoflavones) were used as raw materials to simulate the in vitro digestion process in human oral and gastrointestinal tract. High performance liquid chromatography diode array detector/electrospray ionization quadrupole time of flight mass spectrometry detector (HPLC-DAD/ESI-Q-TOF-MS) was used to detect the variety and content of phenolic compounds before and after the in vitro digestion. The total phenol content (TPC), total flavonoids content (TFC) and antioxidant activity (DPPH, ABTS, FRAP, ORAC) in different digestion stages were determined. The results showed that four phenolic compounds (epigallocatechin, (+)-catechin, epigallocatechin gallate, epigallocatechin gallate) were detected in green tea extract, four phenolic compounds (daidzin, genistin, daidzein and genistein) were detected in soybean extract, and two phenolic compounds (naringin, hesperidin) were detected in citrus peel extract. Among the three food extracts, phenolic compounds in the green tea extract were the most unstable after in vitro digestion, except (+) -catechin, the other three phenolic compounds were almost completely degraded, the loss rate was more than 95%. TPC of green tea, citrus peel and soybean extracts was significantly increased in gastric digestion stage (P<0.05), and significantly decreased in intestinal digestion stage (P<0.05). TFC of green tea extract was significantly increased in oral and gastric digestion stage (P<0.05), and significantly decreased in intestinal digestion stage (P<0.05). TFC and TPC of citrus peel and soybean extract had the same change trend. The four antioxidant activities of green tea extract increased first and then decreased after gastrointestinal digestion. Antioxidant activities of ABTS, FRAP of soybean extract were significantly decreased in oral phase (P<0.05), antioxidant activities of DPPH, ORAC were significantly increased in oral and gastric digestion phase (P<0.05), and significantly decreased in intestinal digestion phase (P<0.05). The ORAC antioxidant activity of citrus peel extract was significantly increased in intestinal digestion stage (P<0.05), and the antioxidant activity of ABTS and FRAP showed a trend consistent with the change of total phenol content in in vitro digestion stage.