## 2 Results and Discussion
### Concentration of Individual Aromas in the Different Families of Volatile Compounds
#### 2.3.4 Terpenes and Norisoprenoids  
The linalool, \(\beta\)-damascenone, citronellol, and meridolol found in the wines analyzed are responsible for varietal aromas [49] and may contribute to improving the perception of the fruity, citrus, and floral aromatic aromas in wines [50]. Linalool and citronellol have aromas of lavender and green lemon, respectively [35], while meridolol imparts aromas that are sweet and fruity [51]. Other compounds like C13-norisoprenoids (including \(\beta\)-damascenone) may have a great sensorial impact on wines and are normally related with floral and exotic fruit aroma notes [24]. Furthermore, some researchers have suggested that this compound also has an indirect impact on wine aroma by enhancing the fruity notes of the ethyl esters [52].  
As can be observed in Table 3, linalool, citronellol, meridol were found in trace amounts. However, the norisoprenoid \(\beta\)-damascenone was found in higher concentrations, and presented significant differences in MT103 wine, respective to Verdejo wine, which could suggested that MT103 has more varietal character than Verdejo wine. With respect to individual aromas, \(\beta\)-damascenone was again present at highest concentrations in the MT103 wine, although high concentrations were also found in two more wines; MS30 and MV67. Furthermore, it was not possible to quantify \(\beta\)-damascenone for MV7 in 2018 (Table 3), and MV67 decreased its concentration by half in 2019 (Table 4). On the other hand, [PERSON] et al. [42] found no significant difference in \(\beta\)-damascenone levels based on the harvest date in Cabernet Sauvignon wines. However, [PERSON] et al. [10] observed a statistically significant harvest time-dependent decreasing trend (\(-15\) days, \(-7\) days, and \(0\) days or full ripeness) for \(\beta\)-damascenone in Pinot Noir and Barbera wines.  
Lower concentrations were found in 2019 with respect to the 2018 season (Table 4). [PERSON] et al. [36] also found lower concentrations of terpenes in Albillo and Muscat wines made from less mature grapes. However, MV67 and MV7 wines presented higher concentrations of terpenes in 2019 for reasons that are not immediately clear, so further studies over more successive years are needed to establish their varietal character or even to study the concentration of bound terpenes. In the present study, terpene concentrations were slightly higher in wines made from mature grapes (2018). This agrees with the findings of [PERSON] et al. [53], who found that the monoterenoid content tended to increase with ripening, while other varietal chemicals (C13 norisoprenoids) increased up to maturity and decreased thereafter. Our study, too, suggests that mature grapes provide a higher level of terpenes (Figure 1D, Tables 3 and 4). [PERSON] et al. [54] also affirmed that advanced grape maturity and greater exposure to the sun favor the accumulation of varietal compounds in the berry. The total h of sunshine recorded between the months of veraison and maturation confirm that the grapes would have received 1732 h of sunshine in 2018, compared with 1717 h in 2019, which would explain the higher concentration of terpenes in 2018.  
Finally, the Verdejo wine had lower terpene concentrations than the wines made from all the white crosses studied in both seasons, which suggests that the crosses might produce more aromatic wines and be good candidates for producing wines with an aromatic quality similar to or higher than that of Verdejo wine.