The effect of cultivar type and ripening on the polyphenol content of date palm fruit

Date Palm (Pheonix dactylifera) fruit contain an array of polyphenols, although how these levels alter with cultivar type and fruit ripening is unclear. Utilising HPLC and LC-ESI-MS/MS, we define and quantify an array of hydroxybenzoic acids, hydroxycinnamic acids and flavonoids in three common cultivars of Dates (Ajwa, Barni and Khalas) at the main ripening stages (kimri, khalal. rutab, tamr). Polyphenols were at highest concentration at earlier stages of ripening, with concentrations reducing with ripening. The khalal stage of the Ajwa cultivar contained significantly higher (P< 0.001) levels of polyphenols than that measured in the Barni and Khalas dates at the same degree of ripening. Furthermore, the Ajwa cultivar was the only one to contain significant quantities of anthocyanidins, in particular at the khalal stage. Our data suggest dates are a significant source of polyphenols, especially if the earlier edible ripening stages are consumed or utilised as food ingredients.