Effect of agricultural sites on differentiation between Chemlali and Neb Jmel olive oils.

The chemical composition, oxidative stability, aroma and sensory profiles of virgin olive oils from two Tunisian cultivars, Chemlali and Neb Jmel, grown in two different locations, the center and south of Tunisia, have been evaluated. There were significant differences between the oils from both cultivars when grown in the two different environments. At higher altitude, the oils showed a greater amount of oleic acid, phenols and a higher oxidative stability, while at lower altitude, the oils had higher saturated and linoleic acid contents. The aroma profiles in Chemlali and Neb Jmel cultivars were also influenced by the pedoclimatic conditions, as shown by the difference in volatiles as a function of the geographical area. The volatile compounds of the monovarietal virgin olive oils were identified and compared using headspace solid-phase microextraction (HS-SPME) technique coupled with GC-MS and GC-FID. The proportions of different classes of volatiles of the oils have shown significant differences throughout the obtained oils. These results suggest that besides the genetic factor, the agronomic conditions affect the volatile formation and, therefore, the organoleptic properties of VOO, and can be used to discriminate and characterize the Chemlali and Neb Jmel olive oils from each region.