Gas chromatography-mass spectrometry-olfactometry was used for the analysis of volatile compounds and key odorants of three less studied Tunisian olive oil cultivars for the first time. A total of 42 aroma compounds were identified and quantified in extra virgin olive oils. The present study revealed that the most dominant volatiles in olive oil samples qualitatively and quantitatively were aldehydes and alcohols, followed by terpenes and esters. Indeed, chemometric analysis has shown a correlation between chemical compounds and sensory properties. The determination of aroma-active compounds of olive oil samples was carried out using aroma extract dilution analysis. A total of 15 aroma-active compounds were detected in the aromatic extract of extra virgin olive oil, of which 14 were identified. On the basis of the flavor dilution (FD) factor, the most potent aromatic active compound was hexanal (FD = 512) in Fakhari olive oil, (FD = 256) in Touffehi oils, and (FD = 128) in Jemri olive oil.

Dynamics of squalene, sterol, aliphatic alcohol, pigment, and triterpenic diol accumulations in olive oils from adult and young trees of the Oueslati cultivar were studied for two consecutive years, 2013-2014 and 2014-2015. Data were compared statistically for differences by age of trees, maturation of olive, and year of harvesting. Results showed that the mean campesterol content in olive oil from adult trees at the green stage of maturation was significantly (p < 0.02) above the limit established by IOC legislation. However, the mean values of campesterol and Δ-7-stigmastenol were significantly (p < 0.01) above the limits in oils from young trees at the black stage of ripening. Principal component analysis was applied to alcohols, squalene, pigments, and sterols having noncompliance with the legislation. Then, data of 36 samples were subjected to a discriminant analysis with "maturation" as grouping variable and principal components as input variables. The model revealed clear discrimination of each tree age/maturation stage group.

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Trees of the olive (Olea europaea L.) cultivar Zalmati grown in Zarzis (Mednine) with different main climate traits (temperature, precipitation, humidity, and wind) were studied for 3 years to evaluate the impact of climate on the quality of olive oil. The effect on quality indices, free fatty acids, peroxide value, UV spectrophotometry, pigment content, and phenol and O-diphenol concentrations, of the three harvesting periods was considered. Linking to the purity parameters (fatty acid, triacylglycerol, total phenols, and tocopherols composition), our results showed a trivial reduction in fatty acid composition and polyphenols content caused by the high temperature. In fact, precipitation strongly affects the pigment content, which showed a significant decrease during rainy seasons. Nevertheless, principal component analysis allowed us to highlight the correlation between parameters and indicates that 57.8% of the variation of monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), MUFA/PUFA, α-tocopherol, C 18:1, and C 18:2 amounts was explained by the mean temperature.

This paper reports the quality indices, the volatile components, phenolic compounds and the oxidative stability of monovarietal Tunisian cultivar (cv. Neb Jmel) extra-virgin olive oils cultivated in eight regions. Headspace solid-phase microextraction and HPLC–DAD were applied to analyze and quantify the volatile and phenolic compounds of the obtained extra-virgin olive oils. Twenty compounds have been identified and quantified, revealing the complex profile of Neb Jmel EVOO, composed, in order of abundance, by secoiridoids, phenolic alcohols, lignans, flavonoids and phenolic acids. A total of 40 volatile compounds belonging mainly to esters, aldehydes, ketones, aliphatic alcohols and hydrocarbons were determined. Significant differences in the proportions of volatile and phenolic constituents of oils from different geographical origins were observed. The major volatile component was the C6 aldehyde (hexanal and (E)-2-hexenal) fraction, whose content was highly variable between the areas studied. The content of (E)-2-hexenal ranged from 50.9 % in the Melloulech EVOO to approximately 39.8 % for El-Ala EVOO