## 2 Results
### Evolution of Volatile Compounds during the Storage in Bottle  
A total number of 26 volatile compounds were identified in all the wines (Table 4). The main goal of the SPME-GC/MS analysis was not to obtain the absolute concentrations of the volatile compounds present in the wine headspace, but to study the relationships between their relative concentrations (profiles) and the technological variables (wine type/stopper type/storage time) with a multivariate statistical approach. The abundances of the volatile compounds (averages and standard deviations of two replicate bottles) were expressed as relative percentage (internal area) considering all the volatile compounds, as reported in Supplementary Materials (tables of volatile compounds' average peak areas in the studied wines). The most represented compounds were short- and medium-chain esters, which included 17 compounds, followed by higher alcohols, short- and medium-chain organic acids and terpenes. During the bottle storage, more than 80% of the total abundance was represented by seven compounds: isopentyl acetate, 1-hexanol, ethyl hexanoate, 2-phenylethyll alcohol, diethyl succinate, ethyl octanoate \begin{table}
\begin{tabular}{c c c} \hline \hline
**No.** & **Esters** & **LRI [Ref.]** \\ \hline
**2** & Ethyl butanoate & 803 [28] \\
**3** & 2-methylbutanoic acid, ethyl ester & 846 [28] \\
**4** & 3-methylbutanoic acid, ethyl ester & 859 [29] \\
**6** & Isopentyl acetate & 876 [30] \\
**7** & 4-Ethylbenzoic acid, 2-butylester & - \\
**10** & Ethyl hexanoate & 999 [30] \\
**11** & Hexyl acetate & 1011 [30] \\
**14** & 4-Methylbenzaldehyde & 1076 [31] \\
**16** & 4-Ethylbenzaldehyde & 1163 [32] \\
**18** & Diethyl succinate & 1179 [33] \\
**20** & Methyl salicylate & 1192 [30] \\
**21** & Ethyl octanoate & 1194 [34] \\
**22** & Benzenacetic acid ethyl ester & 1243 [30] \\
**23** & 2-Phenylethylacetate & 1255 [30] \\
**24** & Ethyl decanoate & 1392 [30] \\
**25** & Ethyl dodecanoate & 1554 [30] \\
**26** & Ethyl hexadecanoate & 1992 [35] \\ \hline
**No.** & **Alcohals** & **LRI [Ref.]** \\ \hline
**5** & 1-Hexanol & 865 [30] \\
**8** & 1-Heptanol & 969 [30] \\
**9** & 1-Octen-3 ol & 980 [28] \\
**13** & 2-Ethyl hexanol & 1028 [36] \\
**15** & Octanol & 1070 [30] \\
**17** & 2-Phenylethyl alcohol & 1112 [28] \\ \hline
**No.** & **Acids** & \\ \hline
**1** & Acetic acid & 599 [28] \\
**19** & Octanoic acid & 1180 [37] \\ \hline
**No.** & **Terpens** & \\ \hline
**12** & Limonene & 1020 [30] \\ \hline \hline \end{tabular}
\end{table} 
Table 4: List of volatile compounds (LRI, linear retention index). and ethyl decanoate. Over 12 months, the modification of the volatile profile was primarily due to the evolution of these compounds. Ethyl octanoate and ethyl decanoate showed a decreasing trend in the early period of bottle storage (T2-T4), followed by an increase until the 12 th month (T5) in red wines. Isopentyl acetate increased after one month (T2) of bottle storage in the three red wines and reached its maximum abundance at three months (T3), probably as a consequence of acid-catalyzed reactions involving fatty acid esters and resulting in the production of acetate esters [38,39]. The sum of higher alcohols decreased in all four of the wines. This reduction was detected in previous studies [40, 41, 42] and can be explained as the result of the previously cited acid-catalyzed esterification reaction [43]. Concerning the total amount of esters, Merlot is notable for having experienced a slight reduction during the 12 months in wine closed with a conventional stopper, whereas the Merlot, Lagrein rose, Lagrein red and St. Magdalener wines closed with the 'blend' stopper showed a higher total ester content at the end of the storage compared to the start of the storage. This latter trend can occur as a consequence of the esterification of branched acids to form ethyl esters [44, 45, 46].