Insight into the phenolics and antioxidant activity of Indian jujube ( Lamk) peel and pulp subjected to the simulated digestion.

To evaluate the release and activity of Indian jujube phenolics , its peel and pulp were subjected to simulated digestions. The phenolics content and antioxidant activity of the digested samples were determined. The results showed that the total phenolics/flavonoids in the peel were respectively 4.63 and 4.48 times higher than that in the pulp. The release of phenolics and flavonoids respectively increased by 79.75% and 39.98% in the peel and 86.34% and 23.54% in the pulp after the intestinal digestion. The correlation between the total phenolics/flavonoids and antioxidant activity was higher in the peel ( > 0.858,  < 0.01) than that in the pulp. The phenolics profiles of the peel were almost the same after the digestion, and four phenolics including naringenin tri-glycoside, quercetin-3--[(2-hexosyl)-6-rhamnosyl] -hexoside, quercetin-3--pentosylhexoside and quercetin-3--(2-pentosyl -rhamnoside)-4'--rhamnoside were found to be the main flavonoids of Indian jujube peel, and they showed high recovery (>89.88%) during the digestion, implying that these phenolics may play a vital role in the function of Indian jujubes.