Contribution of irrigation and cultivars to volatile profile and sensory attributes of selected virgin olive oils produced in Tunisia.

Nowadays, a significant increase in intensively and irrigated managed olive orchards has occurred in Tunisia in the hope to increase the olive production. Aromatic profile with sensory analysis were considered in virgin olive oils from Arbequina, Coratina and Koroneiki cultivars grown intensively under three irrigation treatments (T1, T2 and T3 equivalent to 50%, 75% and 100% ETc.). Results showed that the aromatic quality depends first on the irrigation level applied and second on the cultivar. From sensory analysis, hay-like and greasy were the principal off-flavour detected. As the amount of supplied water increased, volatiles showed different behaviours depending on cultivar and the most important changes occurred in the release of the three alcohols ((E)-2-penten-1-ol, 1-hexanol, (E)-2-hexen-1-ol and phenylethyl alcohol) and hexanal. The most effective by irrigation regimes in separating cultivars were (E)-2-hexenal, (Z)-2-penten-1-ol, (E)-2-hexen-1-ol, fruity, bitter and pungent sensory descriptors. In conclusion, the data obtained herein proved the heavy influence of the cultivar in comparison with irrigation regimes.