## 3 Results and Discussion
### Volatile Composition of the Cabernet Sauvignon Wines  
Cabernet Sauvignon wine samples were collected at the end of wine fermentations and were subjected to volatile analysis. A total of 51 volatile compounds were identified and quantified in all wines using HS-SPME-GC-MS, and the concentration is displayed in Table 2 and Table S2. The volatiles detected were further classified into 8 categories, including 4 acetate esters, 15 ethyl esters, 4 other esters, 14 higher alcohols, 5 fatty acids, 2 aldoketones, 1 C13-norispoprenoid, 5 terpen, and 1 lactone (Table 2). One-way ANOVA and [PERSON]'s post hoc analysis was used to evaluate statistical differences among all volatiles. All compounds except 1-octen-3-ol showed significant differences among wine samples produced using the four fermentation modalities (Table 2). Besides volatile concentrations, the analytes were also determined for their odour activity values (OAV), which is widely used to indicate the contribution of each compound to wine aroma [9; 10; 29]. In all wines, concentrations of 14 compounds exceeded their odour thresholds, implying their direct contribution to wine aroma formation. A total of 36 volatiles failed to surpass their detection thresholds, thus imparting sensory perception indirectly via a synergistic effect, which ultimately can lead to global alterations in wine aroma [9; 42]. A special scenario was found in isoamyl lactate, which was described as contributing to cream and nut aromas [32]. This compound was detected above its sensory threshold in LP wines, but not the remaining wines produced with SC monocultures (Table 2). \begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Compounds**} & \multicolumn{1}{c}{**Aroma Threshold**} & \multicolumn{1}{c}{**D-SC**} & \multicolumn{1}{c}{**Tav-SC**} & \multicolumn{1}{c}{**S-LP**} & \multicolumn{1}{c}{**Pra-AF-LP**} & \multicolumn{1}{c}{**Odover Description**} \\ \cline{2-10} \multicolumn{1}{c}{**Compounds**} & \multicolumn{1}{c}{**Aroma Threshold**} & \multicolumn{1}{c}{**Concentration**} & \multicolumn{1}{c}{**OAV**} & \multicolumn{1}{c}{**Concentration**} & \multicolumn{1}{c}{**OAV**} & \multicolumn{1}{c}{**Concentration**} & \multicolumn{1}{c}{**OAV**} & \multicolumn{1}{c}{**Concentration**} & \multicolumn{1}{c}{**OAV**} & \multicolumn{1}{c}{**Concentration**} & \multicolumn{1}{c}{**OAV**} \\ \hline Isomuraurate & 30(1) & 2277.32 \(\pm\) 3.14\(\pm\) & 75.9 & 18032.63 \(\pm\) 0.57\(\pm\) & 61.1 & 1002.0 \(\pm\) 3.84\(\pm\) & 34.0 & 196.18 \(\pm\) 2.67\(\pm\) & 65.9 & Banna [5] \\ Isomura| acetate & 100(1) & 1858.4 \(\pm\) & 5.0 & 0.1  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Compounds**} & \multirow{2}{*}{**Anuma Threshold**} & \multicolumn{2}{c}{**D-SC**} & \multicolumn{2}{c}{**TA-SC**} & \multicolumn{2}{c}{**S-LP**} & \multicolumn{2}{c}{**PreM-LP**} & \multicolumn{2}{c}{**Other Description**} \\ \cline{2-10}  &  
Remarkable differences were found in ester concentrations between wines made by all tested modalities (Table 2). Among the ethyl esters, ethyl acetate and ethyl lactate were the most prevalent in all wines, with both compounds presenting in lower concentrations in SC monoculture wines compared to LP wines. Concentrations of ethyl acetate ranged between 55.398 mg/L (D-SC) and 66.976 (S-LP) mg/L, all were below the level (150 mg/L), at which it was more likely to impart spoilage aromas (i.e., nail polish remover aroma) rather than contributing to fruity notes [33]. A more striking difference was observed for ethyl lactate (fruity and buttery aroma [43]), which was 6 times higher in all LP wines compared to the D-SC wines. Such accumulation can be due to the fact that more lactic acid was available as its precursor in LP wines [9; 10]. Ethyl lactate in TA-SC wines also retained at a higher level than those in the D-SC samples, but the increase was to a lesser extent compared to the LP wines (Table 2).