## 3 Results and Discussion
### Influence of the Foliar MeI and ACP-MeI Treatments on Must Volatile Compounds
In 2019, the concentration of total alcohols decreased with both MeJ treatments respect to the control one (Table 2). In 2020, n-heptanol concentration did not change with either treatment (MeJ and ACP-MeJ). The content of n-octanol decreased in samples from both treatments (MeJ and ACP-MeJ) with respect to the control grapes. The n-nonanol content decreased only in the ACP-MeJ samples with respect to the control and MeJ grapes. In contrast, 1-octen-3-ol and 2-ethyl-1-hexanol only decreased in MeJ grapes relative to control and ACP-MeJ samples. The total alcohols content, in 2020, decreased in MeJ grapes, while ACP-MeJ did not show significant differences with the control (Table 2). Among the carbonyl compounds, in 2019, heptanal and nonanal decreased their concentrations in the grapes from both treatments with respect to the control. The concentration of (E)-2-octenal and (E)-2-nonenal did not show significant differences between treatments. The content of decanol, (E,E)-2,4-hexadienal, (E,E)-2,4-nonadienal, \(\gamma\)-decalactone, and 6-methyl-3,5-heptadiene-2-one, decreased only with the ACP-MeJ treatment with respect to control and MeJ grapes. This same trend was followed by the content of total carbonyl compounds in grapes (Table 2). In 2020, heptanal, nonanal, (E)-2-nonenal, and decanal decreased their concentration when grapevines were treated with MeJ and ACP-MeJ with respect to control grapes. Moreover, the concentration of (E)-2-octenal, (E,E)-2,4-hexadienal, and (E,E)-2,4-nonadenal decreased only when grapevines were treated with the MeJ with respect to the control and ACP-MeJ samples. On the contrary, \(\gamma\)-decalactone decreased its content in ACP-MeJ treated grapes with respect to control and MeJ ones. The concentration of 6-methyl-3,5-heptadiene-2-one in grapes was not affected by the foliar applications. Total carbonyl compounds, in 2020, decreased in MeJ grapes compared to control and ACP-MeJ samples (Table 2). Regarding the C6 compounds, which, in high concentrations, can provide negative notes, in 2019, the concentration of n-hexanol and n-hexanal decreased in ACP-MeJ grapes compared to control and MeJ samples. The content of (Z)-3-hexen-1-ol + (E)-2-hexen-1-ol decreased in both MeJ and ACP-MeJ grapes relative to the control ones. The concentration of (E)-2-hexenal significantly increased in MeJ grapes respect to the control, whereas its content decreased in ACP-MeJ samples (Table 2). Total C6 compounds followed the same trend as the latter compound, as well as was observed by [PERSON] et al., 2019 [38]. In 2020, n-hexanol, (Z)-3-hexen-1-ol + (E)-2-hexen-1-ol, and (E)-2-hexenal increased their concentration in MeJ grapes respect to the other samples; since these compounds were the majority, total C6 compounds followed the same trend. [PERSON] et al., 2018 [34] demonstrated that the application of MeJ increased the content of C6 compounds in the _Vitis vinifera_ L. cv. Tempranillo variety. However, n-hexanal content increased in MeJ grapes, but decreased in ACP-MeJ samples compared to control. In this way, the increase in C6 aldehydes observed in the studied grapes, as a consequence of MeJ treatment, could be due to modification of the pathways involved in the formation of fatty acids [21]. These compounds are responsible for green aromas [40,48]. For the rest of the aroma compounds determined in the _Vitis vinifera_ L. cv. Tempranillo grapes, in 2019, only methyl jasmonate was quantified, which increased its concentration in grapes from ACP-MeJ foliar treatment with respect to control and MeJ samples (Table 2). In 2020, hexyl acetate, which increased its concentration with both treatments (MeJ and ACP-MeJ), and methyl jasmonate, which decreased its concentration with both treatments (MeJ and ACP-MeJ)), were quantified in grapes. The differences in the amount of volatile compounds found between vintages may be due to climatic differences between them. For example, the difference in average precipitation in August (11.5 L/m\({}^{2}\) in 2019 and 32.9 L/m\({}^{2}\) in 2020).