## 3 Results and Discussion
### Volatile Compounds
#### 3.4.7 Acetate Esters  
Acetate esters are produced during fermentation by combining higher alcohols and acetyl-CoA through the action of specific yeast alcohol acetyltransferaseness. In contrast to ethyl esters, the concentration of acetates depends more on the yeast-specific activity of acetyltransferases coded by the corresponding genes than on the availability of substrates [48; 49; 50]. The concentration of the most abundant acetate in wine, ethyl acetate, was higher in SPA than in SCE wines (Table 11). This coincided with the higher levels of volatile acidity (expressed as acetic acid) (Table 1) and acetaldehyde (Table 6) found in SPA wines. When present in moderate concentrations, as in this case, ethyl acetate contributes to wine aroma with pleasant fruity notes. Due to its higher concentration, its contribution was likely more significant in wines fermented with _S. paradoxus_. The concentrations of other major acetates, such as isoamyl acetate and 2-phenethyl acetate, were higher in SCE-21 and SCE-22 wines compared to their SPA counterparts, respectively (Table 11). This indicated a higher expression of _ATF_ genes that regulate the activity of acetyltransferases and formation of these acetates in _S. cerevisiae_. Further, the higher levels of isoamyl acetate and 2-phenethyl acetate in SCE wines imply their greater contribution to the aroma of _S. cerevisiae_ compared to _S. paradoxus_ wines. Previous findings on acetate production \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{3}{*}{**Co.**} & \multirow{3}{*}{**Volatile Compounds**} & \multirow{3}{*}{**ID**} & \multirow{3}{*}{**LRI\({}_{\text{L}}\)**} & \multirow{3}{*}{**LRI\({}_{\text{I}}\)**} & \multicolumn{6}{c}{**Differences in Concentration**} \\ \cline{6-11}  & & & & & \multicolumn{3}{c}{**One-Way ANOVA**} & \multicolumn{3}{c}{**Two-Way ANOVA**} \\ \cline{5-11}  & & & & \multicolumn{3}{c}{**2021**} & \multicolumn{3}{c}{**2022**} & & \\ \cline{5-11}  & & & & & **SCE** & **SPA** & **SCE** & **SPA** & **Y** & **H** & \(\mathbf{Y}\times\mathbf{H}\) \\ \hline EE41 & Ethyl tetradeanoate & B, C & 2054 & 2054 & 8.30 & 6.67 & 5.95 & 5.23 & n.s. & n.s. & n.s. \\ EE42 & Ethyl 3-hydroxydecanoate & B, C & 2104 & 2102 & 3.24 & 3.06 & **3.17*** & **1.6*** & **SCE** & **21** & * \\ EE43 & Ethyl pentadecanoate & B, C & 2149 & 2151 & n.d. & n.d. & 0.34 & 0.37 & - & - & - \\ EE44 & Ethyl hexadecanoate & B, C & 2251 & 2241 & 21.30 & 13.04 & 7.38 & 7.42 & n.s. & **21** & n.s. \\ EE45 & Ethyl _cis_-11-hexadecenoate & B, C & 2281 & 2236 & 0.80 & 0.91 & n.d. & n.d. & - & - & - \\ EE46 & Ethyl octadecanoate & B, C & 2463 & 2464 & 0.32 & 0.16 & n.d. & n.d. & - & - & - \\ \hline \hline \end{tabular} Abbreviations: Co.—compound’s code; ID—definition of compounds: A—retention timeout with that of a pure standard; B—mass spectra accordant with that from NIST 2.0, Wiley 8, and FFNNSC 2 mass spectra electronic libraries or literature; C—linear retention index (LRI) accordant with an index from literature (compounds with only B in the ID column were considered tentatively identified); LRL—experimental linear retention index; LRI—linear retention index from literature; n.s.—not significant; n.d.—not detected. One-way ANOVA section: different superscript lowercase letters represent statistically significant differences between the two investigated wines determined by one-way ANOVA at \(p<0.05\) for each harvest year separately. Two-way ANOVA section: designations are reported representing yeast (SCE, SPA) and harvest year (21, 22) with higher concentration determined by two-way ANOVA at \(p<0.05\) with yeast (Y) and harvest year (H) as factors. An asterisk indicates a significant interaction between the two factors (Y \(\times\) H). Significant differences are highlighted in bold.  
\end{table} 
Table 10: \(Cont.\)by _S. paradoxus_ compared to _S. cerevisiae_ are somewhat inconsistent. [PERSON] et al. [12] reported similar results for ethyl acetate as those reported in this study, with increased levels following _S. paradoxus_ fermentation.