The date, fruit of the date palm, constitute the staple food of Saharan people. The study of its composition enables not only its valuation, but also offers it the possibility of being used as raw material in various bioproducts eleboration. The objective sought through this study aims to the chemical characterization and evaluation of the antioxidant activity of three varieties of dates : Ghars (date with soft consistency), Deglet-Nour (date with semi-dry consistency) and Degla-Beida (date with dry consistency) of Ouargla oasis harvesting at "Tmar" stage (full maturity). Sugars were identified by thin layer chromatography, the minerals were analyzed by atomic absorption spectrophotometer, the cellulose by Weende’s method, pectins by calcium pectate. The phenolic compounds were measured using Folin-Ciocalteu method, the flavonoids by aluminum trichloride method of and the condensed tannins by the butanol-HCl method. The antioxidant activity was measured by the inhibition test of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical. The results showed that the three varieties of dates are rich in iron, magnesium and potassium and constitute a significant source of calcium. The variety Deglet-Nour is the richest in phenolic compounds with 14.23±0.73 mg of gallic acid equivalents/100 g of dates. The flavonoids content ranges between 0.20±0.05 and 2.39±0.08 mg of rutin equivalents/100 g of dates, the the condensed tannins varies between 0.008±0.00 and 0.06±0.08 mg of tannic acid equivalents/100 g of dates. The ethyl acetate extract of the variety of date Ghars has a high antioxidant activity with an EC50 of 5.72 mg/ml. These results show that the dates of Saharan region of Ouargla can be a good source of natural antioxidants and minerals.

Username
Password