## 3 Results and Discussion  
### Bioactive Characteristics of the White and Red Grape Musst and Wines  
The content of bioactive compounds in grape musts was compared with that of the corresponding wines. Therefore, to determine differences between the bioactive compounds, must-wine interaction was analyzed for the four white and red varieties, highlighted by variance analysis, using the Duncan test (\(p\leq\) 0.05). Figure 1 shows a significant difference between the polyphenic compounds in white musts and wines, demonstrating that fermentation results in the loss of polyphenols. It is noted that, among the varieties taken into study, the must and wine of the Feetesaca Regala variety have the highest total polyphenols contents (563.67 mg GAE/L of must and 471.4 mgGAE/L of wine). Consequently, the antioxidant activity was also the highest, at 12.4294 mmol TE/L. The lowest total polyphenols content corresponds to Riesling Italian must (413.97 mgGAE/L) and Sauvignon Blanc wine (343.29 mmol TE/L), while lower values of antioxidant activity correspond to both must and wine of Sauvignon Blanc. The concentration of tannins in white musts is low, ranging between 10.44 mg/L in the Italian Riesling variety and 15.65 mg/L in the Feetasca Regala variety, while in white wines they were not found due to the white wines' winemaking technology, which only briefly allows contact of the grape juice with the skin. Red musts and wines contain high amounts of tannins, with values between 1414.97 and 4726.6 mg/L in musts and between 1362.7 and 4121.0 mg/L in wines, with higher values corresponding to Merlot must and wine. Compared to the literature data, the total polyphenols contents of the investigated wines were similar to Chardonnay wine (445 mg GAE/L [39] or 379 mg GAE/L [40]) and Italian Riesling (303 mg GAE/L) [41], but they were higher than Sauvignon (262 mg GAE/L) and Terret Sauvignon (289 mg GAE/L) [40], as well as Feetasca Regala (230 mg GAE/L) [16] (Table S2). The antioxidant activity in the literature is close to that obtained in the must and wine from white grapes, specifically Riesling Italian must/wine (8.40/0.09 mmol TE/L) [19] and Feetasca Regala wine (0.93 mmol TE/L) [16] (Table S2). The catechin content in white musts ranged between 104.30 and 282.10 mg catechins/L, with lower values corresponding to the Riesling Italian variety and higher values corresponding to the Feetasca Regala variety. For wines, the catechin content ranged between 18.17 and 63.79 mg catechin/L, with a lower amount in the Muscat Ottonel variety and a higher amount in the Sauvignon Blanc variety (Figure 1). The TCs of the studied white wines were comparable with the literature data for Chardonnay wine (28.7 mg/L), Sauvignon (27.9 mg/L), and Viognier (38.35 mg/L) [40] (Table S2). According to the Duncan test, significant differences (\(p\leq 0.05\)) between the bioactive properties (TPFs, TCs, TTs, AA) of white musts and the corresponding wines were observed for Feetasca Regala and Sauvignon Blanc varieties, mostly based on TPFs and TCs (Figure 1),  
Figure 1: Bioactive characteristics of must and wines of white grape varieties (FR—Feetasca Regala; RI—Riesling Italian; MO—Muscat Ottonel; SB—Sauvignon Blanc): (**a**) Total polyphenols (TPFs) (mg GAE/L); (**b**) total catechins (TCs) (mg catechins/L); and (**c**) antioxidant activity (AA) (mmol TE/L). Different lowercase letters in each graph indicate a significant difference at \(p<0.05\) according to [PERSON]’s multiple range test. while no significant differences were observed in the case of Muscat Ottonel and Riesling Italian musets and wines. The total polyphenols content in red grape musets varied from 3338.89 mg GAE/L for the Cabernet Sauvignon variety to 5611.11 mg GAE/L for the Burgund Mare variety, while the measured values in the corresponding wines varied from 2192.39 mg GAE/L for the Cabernet Sauvignon variety to 2937.10 mg GAE/L for the Merlot variety (Figure 2).