Characterization of virgin olive oil from Southern Tunisia

Fruits from three Tunisian cultivars of Olea europea L. grown in the southeast of Tunisia were harvested at the maturity stage of ripeness and immediately processed with a laboratory mill. There are as yet no data on the chemical composition of virgin olive oils from the southeast of Tunisia, an area characterized by an arid condition of growth for olive trees. Our results showed significant differences in the analytical parameters examined for the three cultivars such as fatty acid composition, total phenols and o-diphenols, and the content of chlorophylls and carotenoids, confirming the importance of genetic factors in the chemical characteristics of the oil. Headspace solid-phase microextraction (HS-SPME) was applied to the analysis of volatile compounds of virgin olive oils. Forty-eight compounds were isolated and characterized by GC-RI and GC-MS, representing 94.1-98.1% of the total amount. (E)-Hex-2-enal, the main compound extracted by SPME, characterized the olive oil headspace for all samples. So, it was clearly shown that there were qualitative and quantitative differences in the proportion of volatile constituents from oils of the various cultivars.