Virgin olive oil aroma: Characterization of some Tunisian cultivars

Fruits from four Tunisian cultivars of Olea europaea L. grown in the North of Tunisia were handpicked at the same ripening degree and processed with a laboratory mill. The oils were submitted to dynamic headspace and their volatile composition was determined. The results showed that the most important contributors to olive oil aroma are C-6 aldehydes, alcohols, and esters. These compounds are biogenerated from polyunsaturated fatty acids through the lipoxygenase (LOX) pathway. Furthermore, they pointed out the predominance of the oxidation of linolenic (LnA) acid over linoleic (LA) acid one. In this predominant part of LOX, the branch A giving rise to trans-2-hexenal, trans-2-hexenol was more important than the branch B giving rise to cis-3-hexenol and cis-3-hexenyl acetate. This pointed out that the isomerization of cis-3-enals forms to trans-2-enal ones is the dominant process of the branch B. The accumulation of the different metabolites in the oils varied according to cultivar indicating a close dependence on the enzymatic store which is genetically determined. (c) 2005 Elsevier Ltd. All rights reserved.