Comparison of Phenolic Content and Antioxidant Activity of the Three Date Palm Varieties of Hajmohamadi, Kabkab, and Khasi (Phoenix dactylifera L.) in Different Ripening Stages

Date palm fruit is one of the highly consumed foods with antioxidant compounds and high nutritive value in Iran. In this study, total phenolic compounds and antioxidant capacity of three varieties of date palm (Hajmohamadi, Kabkab, and Khasi) in three stages of ripening were investigated. This was a laboratory study. Palm fruits of Hajmohamadi, Kabkab, and Khasi varieties in three stages of Khalal, Rotab, and Tamar were collected of Behbahan, Khuzestan province, Iran, in November 2012. Hydroalcholic extracts were prepared by maceration method. Total phenolic content was measured by the Folin–Ciocalteu reagent. Ferric reducing antioxidant power (FRAP), diphenylpicrylhydrazyl (DPPH) free-radical scavenging, and total antioxidant capacity tests were used to evaluate the antioxidant capacity of extracts. Phenolic compound content, ferric reducing power, and total antioxidant capacity increased in Hajmohamadi, Kabkab, and Khasi varieties during ripening. Increase in ferric reducing power was significant. The lowest DPPH test result (IC50), in all three varieties during ripening, was observed in the date stage. Ferric reducing power increases during ripening stages. Moreover, the DPPH radical scavenging capacity decreases in the three varieties of dates during ripening