Chemical Profiles and Antioxidant Activities of Leaf, Pulp, and Stone of Cultivated and Wild Olive Trees (Olea Europaea L.)

In this study, the phytochemical profile including the fatty acids composition and the minerals, the polyphenols, and the proteins contents were quantified on leaves, pulp, and stone of two oleasters trees from southern Tunisia. Two olive cultivars (Zarrazi and Chemlali) were used for comparisons. The antioxidant activities were conducted using the 2,2 '-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and the 2,2-diphenylpicrylhydrazyl (DPPH) assays. Results showed that the pulp and the stone of oleasters (wild olives) were richer in total lipid having, respectively, 16.30% and 9.42% of Dry Weight basis (DW). Qualitatively, the fatty acids profile of pulp and stone from cultivars and oleasters was identical. The oleic acid is the major fatty acid having the highest percentage in the oils from the stone of oleaster1 (69.08%) followed by linoleic acid. However, quantitatively, significant differences in fatty acids composition were noted. The oleaster stones were richer in storage proteins showing that the globulin is the major fraction (50.47%), followed by albumin (25.72%), prolamin (17.61%), and glutelin (6.19%) fractions. Concerning the minerals, results showed that the pulp is richer in potassium (862.87 mg/100 g DW) than leaves (526.50 mg/100 g DW) and stone (136.50 mg/100 g DW). In contrast, the leaves have the highest phosphorus content (42.74 mg/100 g DW). The highest polyphenols content was 711.55 mg/100 g DW in the pulp followed by the leaves and stone. The leaves, pulp, and stone extracts showed high antioxidant activities using DPPH and ABTS assays. The oleasters seem to be a potential source of edible oil, protein, and antioxidants. They could be used as supplements and/or ingredients in oil and fat industries.