# The Impact of GoLo Technology on the Quality Properties of Dealcoholised Wines
## 3 Results and Discussion
### Volatile Compound Analysis
It highlights that compounds such as esters, terpenes, and aldehydes were generally lost in significant percentages across all wine types after this process, with losses approaching nearly 100% in white and rose wines for esters (Table 5). Also, Table 5 shows values with negative numbers, indicating an increase in the concentration of certain aromas after the dealcoholisation process using GoLo technology. This phenomenon occurs in rose wines for norisoprenoids, in red wines for alcohols and phenols, and in white wines for alcohols, phenols, and norisoprenoids. The loss of compounds is linked to the GoLo system technology [5] but also to other dealcoholisation systems such as pervaporation with a PDMS membrane [46]. During the first distillation column process, all volatile compounds are directed towards the final product. However, the efficiency of this separation depends on the volatility of the compound; high-molecular-weight esters are less volatile, while phenols and alcohols, which are more volatile, can be lost more readily compared to esters and terpenes. Figure 5: Heatmap of concentration (ng/mL) of each wine studied after dealcoholisation process using GoLo technology. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Aroma Groups** & **\%R Range** & **\%R Average** & **\%T Range** & **\%T Average** & **\%W Range** & **\%W Average** \\ \hline Esters & 90.2 to 99.3 & 94.9 & 46.1 to 81.2 & 63.2 & 83.8 to 99.5 & 96.1 \\ Alcohols & 32 to 54.3 & 45.2 & (\(-\)98.1) to (\(-\)17.8) & (\(-\)41.46) & (\(-\)62.6) to 2.2 & (\(-\)39.2) \\ Aldehydes & 81.6 to 100 & 95.2 & 48.9 to 100 & 86.3 & 67.5 to 100 & 91.0 \\ Acids & 75.7 to 91.2 & 83.5 & (\(-\)34.7) to 25.2 & 3.6 & 3.7 to 53.4 & 16.2 \\ Terpenes & 52.1 to 89.3 & 72.4 & 74.3 to 90.6 & 79.2 & 4.3 to 76.8 & 45.0 \\ Norisoprenoids & (\(-\)47.2) to 39.8 & (\(-\)11.01) & 11.2 to 38.5 & 21.7 & (\(-\)45.9) to 3.3 & (\(-\)6.9) \\ Phenols & 38.9 to 52.2 & 47.3 & (\(-\)76.3) to 9.8 & (\(-\)16.6) & (\(-\)94) to 16.2 & (\(-\)50.7) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Percentage of reduction (positive values) and increase (negative values) for each aroma group analysed. The concentration of certain compounds did not show a consistent pattern, as they varied significantly across different wine types. For instance, phenylethyl alcohol, which was the most concentrated compound in all wine, demonstrated different trends. Thus, in rose wines, the concentration decreased from 11.785 ng/mL to 10.452 ng/mL (a loss of 13%). In contrast, in white wine, it increased from 15.462 ng/mL to 21.601 ng/mL (a gain of 40%). Red wines showed a more uniform concentration, ranging from 17% to 98%. These observations suggest that, during the distillation process, the more soluble and less volatile compounds increase in concentration after the dealcoholisation process, and this increase is greater depending on the complexity of the matrix (greater for red wines than white wines), so further investigation is needed to understand their behaviour completely. The results presented in Figures 4 and 5 encompass all types of wine without differentiation, as both the lateral dendrogram and the analysed aroma content reveal similarities among different wine varieties that may initially appear distinct. For instance, Figure 4 illustrates that, prior to the dealcoholisation process using GoLo technology, there are notable similarities between Rose 3 (Garnacha) and White 2 (Verdejo), as well as between Red 3 (Garnacha) and Rose 6 (Merlot). This suggests that, despite the differences in grape varieties, there are relationships based on similar aroma profiles, which may be altered following the dealcoholisation process using GoLo technology. Specifically, the samples of Red 3 and Rose 6 become dissimilar mainly due to variations in terpen, aldehydes, and esters. Rose 6 experiences reductions of 71%, 99.9%, and 95% in these aroma components, respectively, while Red 3 exhibits reductions of 70%, 99.9%, and 95%.