Characterization of sterolic and alcoholic fractions of some Algerian olive oils according to the variety and ripening stage

The present study reported for the first time the evolution of some minor compounds (sterols and aliphatic alcohols) composition of four Algerian olive oils according to the cultivar and the maturity stage during the season (2013/2014). Olive samples were collected during eight different harvesting dates. The studied cultivars were Chemlal, Aghenfas, Buichret and Mekki. Ten sterolic compounds, triterpene dialcohols (erythrodiol + uvaol) and seven fatty alcohols were identified and characterized. The results showed a decreasing level of total sterols, β-sitosterol, triterpenic dialcohols, total aliphatic alcohols, tetracosanol (C24), and an increasing level of Δ5-avenasterol according to the maturity process. Linear discriminant analysis (LDA) enabled the classification of the studied varieties on the basis of analytical data and a correct classification rate of 96.5% and 88.6% was achieved using the original and cross validation method respectively. The most discriminating variables have been: cholesterol, campestanol, Δ7-stigmastenol, Δ7-avenasterol, clerosterol, alcohol C22, alcohol C25, alcohol C27