Changes in volatile organic composition of olive oil extracted from cv. ‘Leccino’ fruit subjected to ethylene treatments at different ripening stages

Abstract

BACKGROUND Olive, as a non‐climacteric fruit, is presumed to be ethylene independent with regard to ripening triggering/coordination. Nevertheless, studies have demonstrated that postharvest ethylene treatments induce changes in composition and properties also of non‐climacteric fruits, including aroma profiles, a key quality parameter of extra virgin olive oils. Olive fruit of cv. ‘Leccino’ harvested at two distinct ripening stages (less advanced ripening, LAR; and more advanced ripening, MAR, with Jaén index of 4.58 and 5.10, respectively) were subjected to ethylene (1000 ppm in air) treatment for 24 h before oil extraction. RESULTS Based on multivariate analysis of volatile organic compound (VOCs), the effect of ethylene treatment appeared to be more pronounced in MAR samples. However, differences in organoleptic analysis were also detected in ethylene‐treated LAR olive oils. Ethylene seems to selectively affect linolenic/linoleic acid metabolism, particularly concerning the C5 pathway, and reduce specific defect‐associated compounds. CONCLUSION Exogenous ethylene applied to cv. ‘Leccino’ olives before processing was effective in inducing specific changes in the VOC profiles of the resulting oil. The effect was different depending on the ripening stage of the harvested olives. The lipoxygenase pathway (including the production of C5 compounds) and fermentative‐related compounds appeared to be affected by the treatment. © 2020 Society of Chemical Industry

Geographical origin discrimination of “Ntopia” olive oil cultivar from Ionian islands using volatile compounds analysis and computational statistics

“…1 . The volatile compounds that were identified in the present study are in accordance with previous studies dealing with the cultivar or geographical origin determination of olive oil either from Greece [ 12 , 26 , 28 , 29 ] or other countries [ 16 – 18 , 20 , 22 , 27 , 34 , 38 , 39 ].…”

“…On the contrary, 1,3-bis(1,1-dimethylethyl)benzene was identified in all olive oil samples, recording higher concentration in samples from Zakynthos. This benzene derivative was not reported previously to contribute to the aroma of olive oil of the Koroneiki cultivar from Zakynthos [ 28 ], Picholine marocaine cultivar from Morocco [ 13 ], and Alperujo cultivar from Florence (Italy) [ 39 ], whereas scarce data are available, in general, for this compound in the relevant literature [ 2 , 13 , 22 , 23 , 28 , 39 ]. These phenolic volatiles may give olive oil a bitter and spicy oil flavor [ 2 ].…”

“…Ethanol may give a fermented-like, ripe fruit, and pungent aroma in olive oil, while in combination with other alcohols such as 2-methylpropanol, pentanal, cis -2-penten-1-ol, cis -3-hexenol and octanol may give a sweet and fruity odor, resulting in positive effects to the aroma and quality of olive oil [ 2 ]. Previous studies in the literature dealing with the determination of volatile compounds of olive oil from Morocco (Picholine marocaine cultivar) [ 13 ], Brazil (Arbequina, Arbosana, Picual, Koroneiki, Grapollo, Coratina and Frantoio cultivars) [ 20 ], Greece (Koroneiki cultivar) [ 28 ], and Italy (Leccino cultivar) [ 22 ] did not report the presence of ethanol in the aroma of olive oil samples. However, in the Italian olive cultivar “Alperujo” ethanol was identified in olive oil during the analysis of volatile compounds [ 39 ].…”

“…Finally, 1-propanol was identified only in olive oil samples from Leukada, in small amounts (Table 1 ). 1-Propanol was reported previously to contribute to the aroma of olive oil of the Leccino cultivar from Italy [ 22 ].…”