Tunisian wild olive (Olea europaea L. subsp. oleaster) oils: Sterolic and triterpenic dialcohol compounds

Abstract The aim of the present investigation is to discriminate seven selected wild olive trees by studying their sterol and triterpenic dialcohol compositions with those of VOOs obtained from Chemlali and Chetoui olive cultivars, all growing in the in the same pedoclimatic conditions. The main sterol found in all the samples is β Sitosterol, followed by Δ5-avenasterol These two major sterols are strongly and negatively correlated, and there is a clear differentiation between cultivars. Thus, MAT22 oleaster shows the highest value for β-sitosterol (87.18%), whereas SB12 oleaster is characterised by the lowest percentage of β-sitosterol (71%) and the highest one of Δ5 -avenasterol (21.73%). For the remaining varieties, the levels of b-sitosterol and Δ-5-avenasterol are within the range of 74–86% and 4–17%, respectively. Two triterpenic dialcohols (erythrodiol and uvaol), were also detected besides the sterolic components. Sterol content of oils was below the upper legal limit of 4% in all nalysed samples, with a range from 1.05% to 3.40%. The statistical analyses (PCA and HCA) can explain the variability of the oil composition according to the cultivar. We note a good discrimination between varieties according to sterol and triterpenic dialcohol data. These components seem to be an effective tool to discriminate between the oleasters.