Abstract:The Changes in release of antioxidant active substances (expressed in polyphenols) and flavonoids, as well as antioxidant activity by oxygen radical absorption capacity (ORAC) of pears (Yali, Mili and Fragrant pear) were determined during in vitro simulated gastrointestinal digestion process. The results showed that the maximum polyphenols release of Yali, Mili and Fragrant pear were 2.11-, 1.51- and 2.24-folder higher than that at timepoint 0 h during the gastric digestion process; the biggest flavonoids release were 1.51, 1.92 and 2.67 times more than that at 0 h as well as the maximum ORAC values raised 1.79, 1.79 and 3.12 times respectivly. In simulated gastric digestion and intestinal digestion, the biggest polyphenols release of Yali, Mili and Fragrant pear were 1.83-, 1.99-, 2.58- and 0.92-, 1.17-, 1.18-folder higher than that at timepoint 0 h (gastric digestion and intestinal digestion separately); the biggest flavonoids release were 0.90, 1.21, 1.79 and 0.49, 0.63, 0.63 times as much as that at 0 h, as well as the maximum ORAC values raised 2.78, 2.15,3.42 and 1.34, 1.42, 1.12 times respectivly. This indicates that pepsin, pancreatin and gastric acid can promote the release of antioxidative substances of pear during simulated gastrointestinal digestion, and the release antioxygen may come from hydrolysis of complexes that polyphenols form with proteins, polysaccharides, lipids, etc.
