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Four cultivars (Gondi, Gasbi, Khalt Dhahbi, and Rtob Ahmar) of Tunisian date palm (Phoenix dactylifera L.) fruits at 3 maturation stages, besser, rutab and tamr, were analyzed for their antioxidant activities (AA) using 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl radicals cation, and reducing power (RP) methods. The total phenolic (TPC), total flavonoid (TFC), and condensed tannins (CTC) contents were measured. Results showed that all samples have the highest TPC, TFC, CTC, and AA at besser stage. A significant correlation (p < 0.05) was found between TPC, TFC, CTC and AA during ripening. Sixteen phenolic compounds were identified and quantified by HPLC. The major ones were caffeic, ferulic, protocatechuic, and catechin for the majority of cultivars. Our data indicate that common date fruits are rich in natural antioxidants that might be more widely used by both the general population and the food industry as a source of bioactive human health promoter phytochemicals.

The behaviour of three European olive varieties, Ascolana Tenera, Koroneiki and Picholine, cultivated in the north of Tunisia, was compared to an autochthonous variety, Chétoui. Most of the quality indices and the fatty acid composition showed significant variations between the olive oils. Among the introduced varieties, the Picholine cultivar had the highest value of oleic acid (61%) whereas the Ascolana Tenera cultivar was noteworthy for its lowest content of phenolic compounds (175 mg/kg) and presented the highest level of palmitic acid. The Chétoui variety presented a high content of oleic and linoleic acids. But all samples, both the autochthonous Chétoui and the introduced cultivars, have similar levels of antioxidant compounds, with the exception of phenols. The aroma composition showed significant differences between the oils from the foreign cultivars. The major volatile component was the C-6 aldehyde fraction whose content varied greatly between the different varieties studied: The E-2-hexenal content ranged from 1.6 mg/kg of oil in the Ascolana Tenera variety to .5 mg/kg for the Picholine and Koroneiki cultivars, whereas the Chétoui variety had the lowest levels of volatile compounds, with the exception of the hexanal level which was tenfold higher than in the foreign cultivars. Therefore, our results showed that two of the introduced varieties, Koroneiki and Picholine, showed good adaptation to the Tunisian cultivation conditions. So far, we claim the possibility to develop the successful cultivation of these latter imported varieties in the country.

Fruits of date palm (Phoenix dactylifera L.) are consumed throughout the world and are a vital component of the diet in most Arabian countries. This study has been carried out to evaluate the total phenolic content and the antioxidant activity of four date palm fruit varieties grown in Tunisia. All measurements were made at the 'tamar' stage-the final stage of fruit ripeness. The date varieties were found to be rich in total phenolic ranging from 209.42 mg of equivalent gallic acid ⁄ 100 g fresh weight in Kentichi to 447.73 mg equivalent gallic acid ⁄ 100 g fresh weight in Allig. The date varieties studied were characterised by a high antioxidant activity ranging from 866.82 for the Deglet Nour to 1148.11 lmol Equivalent Trolox ⁄ 100 g fresh weight for Khouet Kenta by the ABTS method. In fact, the DPPH method revealed that Allig having the lowest antioxidant activity (0.72) followed by Deglet Nour (1.53), Kentichi (1.68) and Khouet Kenta variety (1.96). This study suggest that Tunisian date palm fruit may serve as a good source of natural antioxidants and could potentially be considered as a functional food ingredient.