Classification and assessment of antioxidant activity and phenolic content of different varieties of date palm (Phoenix dactylifera) fruits from Iran

Edible parts of date palm fruits (DPF) from Iran have been evaluated for their antioxidant activities (AA) and total phenolic content (TPC) using Trolox equivalent antioxidant capacity, TEAC, and Folin–Ciocalteu methods, respectively. Seven kinds of soft dates (SD), namely Berehi, Mordasang, Mazafati, Kabkab, Khanizi, Shahabi and Medjool dates; four types of semidry dates (SDD), namely Piarom, Zahedi, Halavi and Karoot dates; and one kind of dry date (DD), Rabbi date were used. The AA of the DPF were in the range of 21.31–29.94, 33.36–35.85 and 33.71 µmol Trolox equivalents/100 g fresh weight, while TPC contents were in the range of 250.75–328.57, 356.55–398.23, and 361.46 mg gallic acid equivalents (GAE)/100 g fresh weight for SD, SDD and DD, respectively. Results show that there was a linear relationship between AA and TPC. Finally, transmittance FT-IR spectra of the extracted methanolic date samples were used to develop classification model based on their TPC content.