## 3 Results and Discussion
### Alcohols  
In WDF_to, alcohols accounted for 15 out of the 102 detected analytes, with an overall TIC area of 369.2 \(\times\) 10\({}^{6}\). During storage, a reduction in their number was observed (14 after 30 days and 7 after 24 months), together with their absolute abundance (184.1 \(\times\) 10\({}^{6}\) after 30 d, 173.6 \(\times\) 10\({}^{6}\) after 24 months). The alcohol class did not define the aroma of Gavina(r) WDF samples predominantly, and this was true for all the three aging steps examined. The results for the alcohol class are shown in Table 3.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & & **WDF\_t0** & **WDF\_t1** & **WDF\_t2** & \\ \hline
**Analyte** & **Aroma** & **LRI** & **Area (\(\times\)10\({}^{6}\))** & **Area (\(\times\)10\({}^{6}\))** & **Area (\(\times\)10\({}^{6}\))** & **Ref** \\ \hline Ethanol & Alcoholic & 466 & 22.5 \(\pm\) 0.2 & 2.16 \({}^{\rm a}\) & - & [26, 27, 31, 32] \\ \hline
2-Methyl-3-buten-2-ol & Grass, earthy, oily & 613 & 1.81 \({}^{\rm a}\) & 1.67 \({}^{\rm a}\) & 39.4 \(\pm\) 0.1 & - \\ \hline
1-Penten-3-ol & Horseradish, green, fruity & 686 & 35.8 \(\pm\) 0.2 & 10.4 \(\pm\) 0.3 & - & [6, 23, 27, 31] \\ \hline
2-Methyl-1-butanol & Alcohol, fatty, wine & 741 & 3.59 \({}^{\rm a}\) & - & - & [6, 26, 31, 32] \\ \hline
1-Pentanol & Fermented, yeast & 765 & 29.8 \(\pm\) 0.08 & 22.1 \(\pm\) 0.3 & 62.8 \(\pm\) 0.4 & [6, 25, 26, 27] \\ \hline
2-Penten-1-ol (Z) & Green, phenolic, ethereal & 768 & 41.8 \(\pm\) 0.2 & 7.84 \(\pm\) 0.06 & - & [23, 27, 29, 31] \\ \hline \hline \end{tabular}
\end{table}
Table 3: Composition of the VOC fraction of Gavina® watermelon pomace WDF identified using HS-SPME-GC-MS analysis: alcohols class.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & & **WDF\_t0** & **WDF\_t1** & **WDF\_t2** & \\ \hline
**Analyte** & **Aroma** & **LRI** & **Area (\(\times\)10\({}^{6}\))** & **Area (\(\times\)10\({}^{6}\))** & **Area (\(\times\)10\({}^{6}\))** & **Ref** \\ \hline
2,3-Pentanedione & Buttery, toasted, & & & & & \\  & caramelized & 698 & 4.20 \({}^{\rm a}\) & 2.83 \({}^{\rm a}\) & - & [23, 26] \\ \hline Acetoin & Sweet, milk, & & & & & \\  & buttery, creamy, & 713 & 15.0 \(\pm\) 0.3 & 4.90 \({}^{\rm a}\) & - & [10] \\ \hline
3-Penten-2-one & Bitter, fruity & 742 & - & 2.58 \({}^{\rm a}\) & - & - \\ \hline
1-(1-Cyclohexen-1-yl)-ethanone & - & 869 & 6.57 \({}^{\rm a}\) & 17.3 \(\pm\) 0.2 & 14.5 \(\pm\) 0.2 & - \\ \hline
3,5-Octadien-2-one (E,Z) & Fatty fruity, & & & & & \\  & green hay & 1000 & 14.1 \(\pm\) 0.2 & 37.9 \(\pm\) 0.2 & - & [26, 37] \\ \hline
3,5-Octadien-2-one (E,E) & Fruity, green, & & & & & \\  & grassy & 1018 & 6.21 \({}^{\rm a}\) & 23.4 \(\pm\) 0.3 & - & [26] \\ \hline
2-Cyclopenten-1-one & - & 1065 & - & 8.49 \(\pm\) 0.06 & - & - \\ \hline \hline \end{tabular} \({}^{\rm a}\) SD \(<\) 0.05. LRI = Linear Retention Index.  
\end{table}
Table 2: _Cont._C9 alcohols were not the most prevalent species in any of the aging steps. This observation is in contrast to that reported in the literature [2, 6, 18, 23, 29, 32]. In fact, these species are considered particularly characteristic of the aroma of _Cucurbiaceae_ fruits including watermelon by imparting \"green, fresh, waxy, and cucumber or melon notes\". However, none of the cited studies examined the Gavina(r) variety. The different genotypes, growing areas, and cultivation methods could explain these differences in the flavor profiles. We identified only 2,6-nonadien-1-ol and 6-nonen-1-ol in WDF_t0.  
The amount of 1-pentanol significantly increased from WDF_t1 to WDF_t2, and progressively imparted fermented notes. This compound mainly originates from the radical oxidation of linoleic acid and, to a lesser extent, from lycopene degradation [25]. Benzyl alcohol was the only aromatic alcohol detected after 30 days (WDF_t1) and, to a lesser extent, after 24 months (WDF_t2) of storage. It imparts sweet, floral, and fruity notes, and is associated with the degradation of phenylalanine.