Virgin olive oil volatile compounds from lipoxygenase and characterization of monovarietal olive oils obtained from different Tunisian mills

The aim of this study was to evidence the differences on the aroma compounds of Chétoui monovarietal olive oils collected from different oil mills from Béja region (Northwestern Tunisia). The volatile compounds of the studied oil samples were separated, identified and quantified, using a HS-SPME coupled to GC-MS. The products of lipoxigenase (LOX) cascade were generally the major components of volatile fraction of olive oil. In this study we are interested to evaluate the C5 and C6 compounds that already been identified as responsible for positive odour properties of olive oil. The C6 compounds were the major components in all virgin olive oil headspaces; they ranged between 94.9 (Slouguia Mill) and 99.3% (Nefza 1 Mill) from the whole LOX products. In addition to the C6 compounds, the headspace of tested olive oils shows a small amount of C5 compounds, between 0.7 and 5.1% of total LOX products. Results demonstrated a large variability in qualitative and quantitative aroma composition according to the oil mill location. Most of the Chétoui oil samples from Béja region revealed high amounts of LOX products. Chétoui cultivar is widely grown in different sites of Béja. It is influenced by the different climatic conditions. The obtained oils strongly differed according to the production area.