XING Huiying, HUANG Li, DING Bo, ZHAO Wangfeng, ZHAO Jixin, ZHANG Xiaofeng, WANG Xingrui
Effects of in vitro digestion on partition behavior, bioaccessibility and bioavailability of five polyphenolics were evaluated, which included carnosic acid, rutin, chlorogenic acid, EGCG and quercetin. The partition coefficients, contents and antioxidant activity of the five polyphenols after in vitro digestion were determined using ultrasonic-shaking bottle and high performance liquid chromatography (HPLC). The results showed that when lgP value of carnosic acid, rutin, chlorogenic acid and quercetin between 0 and 3 and pH value were 1.5 and 5.8, the four phenolic compounds could cross the gut membranes and be absorbed in intestine with better hydrophilic and hydrophobic properties. However, EGCG was difficult to cross the gut membranes if lgP was less than 0. Likewise, at pH 7.8, EGCG, rutin and chlorogenic acid were not able to cross the gut membranes with their lgP values within the range from -3 to -1. On the contrary, both quercetin and carnosic acid could transport across membranes showing stronger hydrophilic ability. Besides, EGCG and chlorogenic acid showed higher DPPH radical scavenging and ferrous reduction ability. After in vitro digestion, the phenolic bioacceptability index (PAC) of rutin was highest, while PACs of the other four polyphenols were smaller than 1, and the phenolic bioavailability index (PAV) of the five polyphenols were also small than 1. Furthermore, the antioxidant bioacceptability indexes (BAC) of EGCG and chlorogenic acid were high, but the antioxidant bioavailability index (BAV) of quercetin was the highest. Moreover, quercetin showed the highest BAV value, while carnosic acid′s BAV value was lowest which relation to its different polarity and structure. And there were no significant differences in BAV value of rutin, chlorogenic acid and EGCG after in vitro digestion (P<0.05). The present study provided a theoretical basis for the development of functional foods rich in quercetin, chlorogenic acid, EGCG and other polyphenols.