## 3 Results and Discussion
### Physical and Chemical Analysis of Grapes and Wines
#### 3.1.2 Physicochemical Analysis of the Three Different Groups of Petit Manseng Wines
The differences in total phenol, tartaric acid ester, and flavanol content among the three groups of wine samples were significant (\(p<0.05\)), and the total phenol and tartrate content in group B and C samples was higher than in group A samples (Tables 3 and 4). Total phenols, including flavonoids and non-flavonoids, are crucial for wine color stability and sensory quality. As shown in Table 4, the content of total phenols in Group C (413.67 \(\pm\) 0.58 mg/L) is the highest, followed by Group B (332.67 \(\pm\) 2.52 mg/L) and Group A (321.67 \(\pm\) 1.15 mg/L). Higher total phenols enhance antioxidant capacity, which helps maintain the stability of wine color during aging. The significant difference among groups (\(p<0.05\)) indicates different phenolic accumulation levels, potentially affecting color intensity and hue. Tartrate, mainly potassium tartrate, is the salt form of tartaric acid. In the table, tartrate content follows Group C (18.68 \(\pm\) 0.56 mg/L) \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Color-Related Parameters**} & \multicolumn{3}{c}{**Wine Samples**} \\ \cline{2-4}  & **A Group** & **B Group** & **C Group** \\ \hline L* & 95.47 \(\pm\) 0.46 a & 95.44 \(\pm\) 0.46 a & 91.95 \(\pm\) 0.33 b \\ A* & \(-\)8.28 \(\pm\) 0.03 a & \(-\)7.50 \(\pm\) 0.14 b & \(-\)7.19 \(\pm\) 0.01 c \\ B* & 42.96 \(\pm\) 1.46 b & 45.03 \(\pm\) 1.39 b & 52.80 \(\pm\) 0.27 a \\ Chromaticity & 0.58 \(\pm\) 0.02 c & 0.62 \(\pm\) 0.01 b & 0.86 \(\pm\) 0.01 a \\ hue & 3.34 \(\pm\) 0.04 a & 2.87 \(\pm\) 0.17 b & 2.89 \(\pm\) 0.09 b \\ Total phenols (mg/L) & 321.67 \(\pm\) 1.15 c & 332.67 \(\pm\) 2.52 b & 413.67 \(\pm\) 0.58 a \\ Tartrate (mg/L) & 15.64 \(\pm\) 0.31 c & 16.71 \(\pm\) 0.17 b & 18.68 \(\pm\) 0.56 a \\ Flavanols (mg/L) & 36.82 \(\pm\) 0.27 c & 35.51 \(\pm\) 0.32 b & 38.24 \(\pm\) 0.85 a \\ \hline \hline \end{tabular} Note: Information is presented as ‘mean \(\pm\) standard deviation’ and different letters in the same column indicate significant differences (\(p<0.05\)).  
\end{table} 
Table 4: Wine Color Related Parameters. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Physical and Chemical Indicators**} & \multicolumn{3}{c}{**Wine Samples**} \\ \cline{2-4}  & **A Group** & **B Group** & **C Group** \\ \hline Alcohol content/\% & 12.03 \(\pm\) 0.02 c & 12.12 \(\pm\) 0.01 b & 12.27 \(\pm\) 0.05 a \\ pH & 3.42 \(\pm\) 0.04 c & 3.55 \(\pm\) 0.03 b & 3.71 \(\pm\) 0.03 a \\ Total acid/(g/L) & 7.29 \(\pm\) 0.06 b & 7.34 \(\pm\) 0.07 b & 7.61 \(\pm\) 0.04 a \\ Volatile acids/(g/L) & 0.77 \(\pm\) 0.02 b & 0.69 \(\pm\) 0.04 c & 0.86 \(\pm\) 0.01 a \\ Free sulfur/(mg/L) & 48 \(\pm\) 1.00 c & 51 \(\pm\) 1.18 b & 53 \(\pm\) 0.11 a \\ Total sulfur/(mg/L) & 152 \(\pm\) 1.00 c & 157 \(\pm\) 0.37 b & 162.33 \(\pm\) 0.58 a \\ glycerol/(g/L) & 8.28 \(\pm\) 0.04 c & 9.89 \(\pm\) 0.02 b & 15.69 \(\pm\) 0.07 a \\ \hline \hline \end{tabular} Note: Information is presented as ‘mean \(\pm\) standard deviation’ and different letters in the same column indicate significant differences (\(p<0.05\)).  
\end{table} 
Table 3: Physical and chemical markers of wine specimens. Group B (16.71 \(\pm\) 0.17 mg/L) > Group A (15.64 \(\pm\) 0.31 mg/L). It reflects wine's physical stability (crystallization risk during storage) and indirect acid-base balance. Different from free tartaric acid, tartrate represents the \"bound state\" of tartaric acid, influencing color-related pH--pigment interactions. Including tartrate in the table complements tartaric acid data, providing insights into wine stability and color-related chemical equilibria. Flavanols (e.g., catechins, proanthocyanidins) play a key role in wine color development. Group C has the highest flavanol content (38.24 \(\pm\) 0.85 mg/L), followed by Group A (36.82 \(\pm\) 0.27 mg/L) and Group B (35.51 \(\pm\) 0.32 mg/L). These polyphenols enhance color via copigmentation and polymerization with anthocyanins. The three groups of wine samples exhibited similar luster, as well as a yellow-green hue.