Effects of the Ripening Stage on Phenolic Profile, Phytochemical Composition and Antioxidant Activity of Date Palm Fruit

Four cultivars (Gondi, Gasbi, Khalt Dhahbi, and Rtob Ahmar) of Tunisian date palm (Phoenix dactylifera L.) fruits at 3 maturation stages, besser, rutab and tamr, were analyzed for their antioxidant activities (AA) using 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl radicals cation, and reducing power (RP) methods. The total phenolic (TPC), total flavonoid (TFC), and condensed tannins (CTC) contents were measured. Results showed that all samples have the highest TPC, TFC, CTC, and AA at besser stage. A significant correlation (p < 0.05) was found between TPC, TFC, CTC and AA during ripening. Sixteen phenolic compounds were identified and quantified by HPLC. The major ones were caffeic, ferulic, protocatechuic, and catechin for the majority of cultivars. Our data indicate that common date fruits are rich in natural antioxidants that might be more widely used by both the general population and the food industry as a source of bioactive human health promoter phytochemicals.