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.
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.