## 3 Results and Discussion
### Influence of the Foliar MeI and ACP-MeI Treatments on Must Volatile Compounds
In 2020, (E)-\(\beta\)-damascenone (Figure 2a), (Z)-\(\beta\)-damascenone (Figure 2b), and \(\beta\)-cyclocitral (Figure 2d), did not suffer variations in their content in Mej and ACP-Mej grapes with respect to control samples. In this season, \(\beta\)-ionone (Figure 2c) significantly increased its amount in Mej grapes with respect to ACP-Mej and control grapes. The increase of \(\beta\)-ionone with Mej may be justified because \(\beta\)-ionone is a derivative of \(\beta\)-carotene [39], and Mej accelerates its degradation [45]. TDN (Figure 2e) increased its concentration in grapes from both treatments (Mej and ACP-Mej) with respect to control grapes. As for total C\({}_{13}\) norisoprenoids (Figure 2f), in 2020 neither treatment had a significant effect on its amount with respect to control samples. Interestingly, C\({}_{13}\) norisoprenoids, derived from the breakdown of carotenoids via chemical, photochemical and oxidase-coupled degradation or enzymatic cleavage [5], generally unchanged with the Mej treatments in 2020. These results contrast with those obtained by [PERSON] et al., 2019 [38], where the application with Mej decreased the amount of C\({}_{13}\) norisoprenoids. Terpeneoids and C\({}_{13}\) norisoprenoids are very important in the floral aroma of grapes. Respect to the C\({}_{13}\) norisoprenoids, \(\beta\)-damascenone and \(\beta\)-ionone are the most important, since they strongly contribute to the desirable flavor and odor in wines, due to their low perception thresholds [40; 46]. Figure 3 shows the concentration of benzenoids found in the control and in the grapes from the foliar treatments with Mej and ACP-Mej, in 2019 and 2020 seasons. In 2019, 2-phenylethylanol (Figure 3a), eugenol (Figure 3c) and benzyl alcohol (Figure 3d) decreased their concentration in grapes from both treatments (Mej and ACP-Mej) with respect to control grapes, with significantly lower content in ACP-Mej samples. In the study of [PERSON] et al., 2020 [12], 2-phenylethylanol also decreased when Mej is applied to vines. 2-Phenylethanol (Figure 3b) significantly decreased its amount in grapes from ACP-Mej treatment with respect to control and Mej samples. Finally, in 2019, the content of total benzenoids (Figure 3e) decreased with both treatments respect to control samples, with significantly lower content in ACP-Mej grapes. This trend was also observed in the work of [PERSON] et al., 2019 [38]. Regarding to the 2020 season, the concentration of 2-phenylethylanol (Figure 3a) and benzyl alcohol (Figure 3d) increased in ACP-Mej grapes with respect to those from the other two samples. 2-Phenylethanol and benzyl alcohol, which in grapes derive from aromatic amino acids, were the principal benzenoid compounds [5]. The content of 2-phenylethylanol in grapes (Figure 3b) showed no significant differences in Mej treatments with respect to the control. Eugenol was not detected in grapes in this second season (Figure 3c). The concentration of total benzenoids (Figure 3e) significantly increased with the ACP-Mej treatment with respect to the control and Mej ones. Terpenoids, C\({}_{13}\) norisoprenoids, and some benzenoid compounds are the most important grape aroma compounds present in the pulp and skin of the berries in both free and glycoside forms. These compounds are transferred to the wine during the winemaking and depend on the process used [47]. Table 2 shows the concentration of alcohols, carbonyl compounds, C6 compounds, and other compounds in grapes from the control, MeJ, and ACP-MeJ foliar treatments, in 2019 and 2020 seasons. As regards to the alcohols in the 2019 season, the concentration of n-heptanol decreased with both MeJ and ACP-MeJ treatments with respect to the control grapes, being significantly lower the concentration in ACP-MeJ grapes. Both, n-octanol and n-nonanol decreased their concentrations in ACP-MeJ grapes with respect to control and ACP-MeJ samples; while the content of 1-octen-3-ol and 2-ethyl-1-hexanol decreased in grapes from both treatments (MeJ and ACP-MeJ) to the same extent.