OPTIMISATION DES CONDITIONS D’EXTRACTION DES POLYPHENOLS DE DATTES LYOPHILISEES (Phoenix dactylifera L) VARIETE GHARS

Abstract

This work was conducted to optimize extraction conditions of polyphenols from date fruit variety Ghars (Kimri I or Kh’lal). The effects of solvent type (methanol and ethanol), solvent/water ratio, sample/solvent ratio and extraction time were studied. High values of total polyphenols content (PPt) were obtained at an 80/20 solvent/water ratio, at a 1/6 solid/liquid ratio and at 5 hours. The optimization results showed that the methanol was the most efficient solvent for polyphenols extraction. The evolution of total polyphenols content during three stages of ripening (Kimri I or Kh’lal I, Khalal or Bser and Tmar) was studied. The PPt content decreased from 892.14 mg EAG/10g of dry weight (DW) at Kimri I stage to 4.22 mg EAG/10g DW at Tamr stage.