Phenolic composition and antioxidant capacities of ten Algerian date (Phoenix dactylifera L.) cultivars: A comparative study

Phenolic compounds and antioxidant capacities of ten Algerian date (Phoenix dactylifera L.) cultivars were investigated. The total phenolic, flavonoid, flavonol and condensed tannin contents of the different cultivars were measured using colorimetric methods. Free phenolic acid and flavonoid profiles of the date cultivars were analyzed by high performance liquid chromatography with diode array detection (HPLC-DAD), while antioxidant capacities were evaluated in vitro using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl radical and hydrogen peroxide, ferric reducing power, and ferrous ion chelating ability. The results showed that the cultivars exerted different antioxidant capacities, and had different phenolic acid and flavonoid patterns. Among the tested cultivars, Ghazi, Arechti and Sebt Mira possessed the strongest antioxidant capacities and the highest phenolic contents. Four phenolic acids (gallic, ferulic, coumaric and caffeic acids) and five flavonoids (isoquercetrin, quercetrin, rutin, quercetin and luteolin) were identified and quantified.