Leaf mineral profiling and its correlation with oil physicochemical traits from four olive (Olea europaea L.) cultivars grown in Morocco as affected by olive ripening stages

Abstract

We investigated genotypic effects on the olive leaves mineral profile and its correlation with soil minerals. Likewise, olive oil extracted from four Mediterranean cultivars (‘Arbequina’, ‘Haouzia’, ‘Menara’, and ‘Picholine Languedoc’) at early and full ripening stages, was studied in terms of basic quality indices, fatty acids, sterols, pigments, and polyphenols. Our outcomes reveal important variations among cultivars and between ripening stages in terms of olive leaf elemental profiling and oil physicochemical traits, while there were no significant (p < 0.05) differences in soil mineral profiling. However, mineral profiling of leaves, basic quality indices, pigments, and polyphenols content of oils showed important inter-cultivar variations. Regarding fatty acid composition, oleic acid (C18:0) was the most abundant. For phytosterols profile, β-sitosterol was found to be the major phytosterol followed by campesterol. Olive oil from fully ripe fruits was marked by reduced chlorophylls (up to − 67.1%), carotenoids (up to − 68.73%) in ‘Menara’ and polyphenols (up to − 45.95%) in ‘Picholine Languedoc’, but an increase of total sterols (up to + 23.5%, ‘Haouzia’). Likewise, saturated (SFA) and monounsaturated fatty acids (MUFA) tended to decrease (up to − 13.5% and − 6.44%, respectively) found in ‘Menara’. However, ‘Arbequina’ had an inceased SFA (+ 7.35%) and MUFA (+ 8.62%). Polyunsaturated fatty acids tended to increase (up to + 41.98%, ‘Menara’) except for ‘Picholine Languedoc’ (− 7.92%). These outcomes were confirmed by principal component analysis with important positive and negative correlations among minerals and oil physicochemical traits. These results showed that the analyzed components could be considered as specific markers to discriminate the studied cultivars. Graphical abstract