Methyl jasmonate application to increase volatile compounds of Vitis labrusca L. grape berries cultivated under subtropical conditions

There has been increased demand for eco-friendly means to improve the bioactive content of fruits. Various studies have focused specifically on methyl jasmonate (MJ), a plant growth regulator. Field applications of MJ appear to induce secondary metabolism in Vitis vinifera L. grapes; however, few studies have focused on the species Vitis labrusca L., even though its cultivars represent approximately 80% of processed grapes in Brazil. Therefore, this study aimed to evaluate the best period for MJ application on V. labrusca L. grapes in the field and the impact on free volatile compounds. The project was conducted in Rio Grande do Sul state in south Brazil over two consecutive years. Free volatile compounds were extracted through solid-phase microextraction, identified using gas chromatography-mass spectrometry (GC-MS), and the results were analyzed by multivariate statistics. Optimal results were found when MJ application occurred during two periods, véraison and pre-harvest. For both harvests, an increase in esters and aldehyde levels without interference in organic acid content was found. Increasing volatile compounds in V. labrusca grapes could be an interesting area for future study, since a decrease in total content occurs during processing, particularly for juice and jellies.