Effect of different drying modes on phenolics and antioxidant potential of different parts of wild pomegranate fruits

Drying of different parts of wild pomegranate fruits such as arils, flavedo (peel), albedo (inner membrane) and pomace (residue remains after juice extraction from arils) were carried out with four different methods viz. natural sun drying (D-1), solar tunnel drier (D-2), mechanical cabinet (D-3) and oven (D-4) drying. Different attributes such as yield, drying time, moisture, total phenols (TP), total flavonoids (TF) and antioxidant properties of dried samples (arils, flavedo, albedo and pomace) were evaluated separately during the study. Out of which, one drying method (D-3) with one fruit part (flavedo) was selected for comparison on the basis of highest TP, TF, DPPH antioxidant activity (AA), metal chelating activity (MA) and ferric reducing antioxidant power (FRAP). The functional groups of mechanical cabinet dried arils and flavedo were analyzed by FTIR, which indicates the presence of significant amount of phytochemicals in flavedo than arils. Further, effect of drying temperature shows that lyophilized flavedo had comparatively higher L* (33.40), a* (3.68), b* (13.78) values, TP (61.87 mg GAE/g), TF (8.48 mg QuE/g), AA (91 %), MA (63.86 %) and FRAP (3.40 mu M Fe2+/g) as compared to mechanical cabinet dried flavedo. The study concluded that lyophilized wild pomegranate fruit flavedo could be utilized in pharmaceutical and nutraceutical industries to make various functional/nutraceutical foods.