Effect of in vitro digestion on antioxidant capacity of pomegranate co-products extracts

From value-addition viewpoint, the aim of this study was to evaluate the stability of antioxidant capacity of pomegranate fruit co-products in different solvent extracts using the FRAP, DPPH ̇ and ABTS ̇+ assays during in vitro digestion. Antioxidant capacity in the investigated assays were in the order of peel > marc > juice throughout the in vitro digestion irrespective of the extraction solvents used. Peel extracts showed between 5 to 75-fold of antioxidant capacity than juice and marc extracts. Interestingly, contrary to the anti-radical activities measured by DPPH and ABTS assays, the FRAP values increased significantly in gastric phase of digestion for all the extracts followed by 10 to 26% decrease in the duodenal digests. Findings from this study also showed that pomegranate antioxidant during in vitro digestion may not reflect the pre-digested antioxidant capacity. Thus, it is important to provide biologically relevant information that reflect antioxidant activity after in vitro digestion.