## 3 Results
### Comparative Analysis of the Characteristics of the Investigated Red Wines  
The parameters of the individual Regent variety grape musts used for fermentation were as follows: MD must--extract value 22 \({}^{\circ}\)Blg, pH 3.63, total acidity as tartaric acid 5.01 g/L; WJ must--extract value 21 \({}^{\circ}\)Blg, pH 3.56, total acidity as tartaric acid 5.64 g/L; and DB must--extract value 20 \({}^{\circ}\)Blg, pH 3.62, total acidity as tartaric acid 5.7 g/L. Fermentation was controlled by weight loss related to CO\({}_{2}\) release until a constant weight was achieved (Table 3). Table 4 shows the key parameters of the DB, MD, and WJ wines obtained. The differences in the ethanol content between the wines were not statistically significant, with a mean of 11.09% vol. The pH values were significantly lower for DB and MD wines (3.7-3.72) compared to WJ wine (3.88). The total acidity (TA) of DB and WJ wines (4.72-4.92 g/L) was significantly lower than that of MD wine (7.24 g/L). DB and WJ wines were characterised by significantly higher TPC values (about 25-30%) than MD wine. DB, MD, and WJ wines statistically differed in DPPH values, glucose, fructose, and lactic acid contents. The DPPH value was the lowest for MD wine and the highest for WJ wine, which was correlated with TPC values. Malic acid was not detected in any of the wines, whereas lactic acid was present in all the wines, which means that MLF took place. Charts showing differences in the above parameters among the wines studied are included in Supplementary Materials (Figures S1-S5).  
The data presented in Table 4 were analysed using tb-PCA, and the results are shown in Figure 3. MD wine was characterised by the highest values of total acidity, and fructose and lactic acid concentrations, WJ had the highest pH and DPPH values, and DB had the  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Wine** & **Eh\% vol. \({}^{*}\)** & **pH \({}^{*}\)** & **TA g/L \({}^{*}\)** & **TPC mg** & **DPHA** & **Glu g/L \({}^{*}\)** & **Fru g/L \({}^{*}\)** & **LA g/L \({}^{*}\)** & **AA g/L \({}^{*}\)** \\ \hline DB & 11.02 \(\pm\) 0.51 \({}^{\circ}\) & 3.72 \(\pm\) 0.08 \({}^{*}\) & 4.92 \(\pm\) 0.08 \({}^{*}\) & 3369 \(\pm\) 122.82 \({}^{*}\) & 10 \(\pm\) 0.34 \({}^{\circ}\) & 2.01 \(\pm\) 0.06 \({}^{\circ}\) & 0.81 \(\pm\) 0.02 \({}^{\circ}\) & 3.21 \(\pm\) 0.09 \({}^{\circ}\) & nd \\ \hline MD & 11.48 \(\pm\) 0.27 \({}^{\circ}\) & 3.70 \(\pm\) 0.06 \({}^{*}\) & 7.24 \(\pm\) 0.42 \({}^{\circ}\) & 2677 \(\pm\) 299.87 \({}^{*}\) & 7.43 \(\pm\) 0.39 \({}^{*}\) & 1.89 \(\pm\) 0.06 \({}^{\circ}\) & 3.89 \(\pm\) 0.07 \({}^{*}\) & 4.41 \(\pm\) 0.10 \({}^{\circ}\) & 1.40 \(\pm\) 0.05 \({}^{\circ}\) \\ \hline WJ & 10.78 \(\pm\) 0.25 \({}^{*}\) & 3.88 \(\pm\) 0.05 \({}^{\circ}\) & 4.72 \(\pm\) 0.19 \({}^{*}\) & 3495 \(\pm\) 234.65 \({}^{*}\) & 11.63 \(\pm\) 0.43 \({}^{\circ}\) & 1.23 \(\pm\) 0.05 \({}^{\circ}\) & 0.69 \(\pm\) 0.03 \({}^{*}\) & 4.02 \(\pm\) 0.05 \({}^{\circ}\) & 0.66 \(\pm\) 0.03 \({}^{*}\) \\ \hline \hline \end{tabular}  
* Mean values \(\pm\) standard deviations; values with the same superscript letters in the same column and the same variable are not significantly different (\(p<0.05\)). Abbreviations: Eth—concentration of ethanol, TA—total acidity, TPC—total polyphenol concentration, DPPH—analysis of antioxidant activity, Glu—glucose concentration, Fru—fructose concentration, LA—lactic acid concentration, AA—acetic acid concentration; nd—not detected.  
\end{table}
Table 4: Analysis of key parameters of red wines.  
highest glucose concentration. Figure 3 also shows that the lowest glucose and ethanol contents were found for WJ, the lowest lactic acid content was detected in DB, and the lowest TPC value was recorded for MD wine.