# Quality Characteristics and Antioxidant Activities of Six Types of Korean White Wine
## 3 Results and Discussion
### Volatile Aromatic Compounds in Korean White Wines  
Even under similar climatic, soil, and environmental conditions, the chemical composition of grapes can vary significantly across different grape cultivars [52]. Diverse volatile aromatic compounds, such as esters, higher alcohols, monoterenes, and acids, can be produced during the fermentation process owing to the presence of various volatile aromatic compounds (precursors) in different grape cultivars, all of which play a vital role in determining wine quality [34; 53]. In the six different white grape cultivars examined in this study, the distribution of volatile aromatic compounds differed significantly after alcohol fermentation. Through GC-MS analysis, 2 acels, 3 acids, 4 aldehydes, 16 higher alcohols, 30 esters, and 8 monoterenes were identified (Table 4). The acetal group, which is abundantly found in distilled alcoholic beverages, contributes to pleasant aromas such as apple, pineapple, cherry, and fruity aromas [54]. Among the six white wines, the SM and KN wines exhibited higher levels of the acetal group than the other wines. Acids also contribute to wine aroma. Short-chain acids such as acetic, propanoic, and butanoic acids are formed as metabolites of alcoholic fermentation, whereas medium-chain acids such as hexanoic, octanoic, decanoic, and dodecanoic acids are possibly formed as intermediates in long-chain fatty acid biosynthesis [55]. In the current study, three long-chain acids, namely, heptanoic, octanoic, and decanoic acids, were detected, with distinctive distribution patterns in each wine. Low levels of heptanoic acid were detected across all the wines, whereas high levels of octanoic acid were found in the SB and CS wines. Conversely, higher levels of decanoic acid were observed in the CB, KN, and CS wines than in other wines. Interestingly, the CS wine had significantly higher levels of both octanoic \begin{table}
\begin{tabular}{l c c c c c} \hline \hline
**Item** & **CB** & **SM** & **SB** & **KN** & **VB** & **CS** \\ \hline Hue & 3.26 \(\pm\) 0.04 e & 3.91 \(\pm\) 0.02 b & 3.50 \(\pm\) 0.10 d & 3.78 \(\pm\) 0.09 c & 2.53 \(\pm\) 0.01 f & 4.74 \(\pm\) 0.06 a \\ Intensity & 0.16 \(\pm\) 0.01 c & 0.17 \(\pm\) 0.01 c & 0.11 \(\pm\) 0.00 d & 0.16 \(\pm\) 0.01 c & 0.38 \(\pm\) 0.02 a & 0.21 \(\pm\) 0.01 b \\ [PERSON]’s color values & & & & & & \\ L & 61.24 \(\pm\) 0.11 a & 60.69 \(\pm\) 0.23 b & 61.03 \(\pm\) 0.13 ab & 60.39 \(\pm\) 0.13 c & 58.96 \(\pm\) 0.16 d & 60.90 \(\pm\) 0.19 ab \\ a & 0.19 \(\pm\) 0.00 c & 0.30 \(\pm\) 0.01 b & 0.22 \(\pm\) 0.01 c & 0.04 \(\pm\) 0.01 d & 1.70 \(\pm\) 0.10 a & \(-\)0.19 \(\pm\) 0.03 e \\ b & 1.04 \(\pm\) 0.09 e & 2.67 \(\pm\) 0.13 c & 0.12 \(\pm\) 0.01 f & 1.44 \(\pm\) 0.06 d & 7.76 \(\pm\) 0.25 a & 4.93 \(\pm\) 0.18 b \\ \hline \hline \end{tabular} Different letters within the same column indicate significant differences (\(p<\) 0.05).  
\end{table} 
Table 3: Hue, intensity, and Hunter’s color values of white wines produced using six types of white grape cultivars grown in Korea. and decanoic acids, whereas other wines showed higher levels of only one of these acids. Acetaldehyde, an intermediate product in the formation of ethanol and glycerol during fermentation, can impart an off flavor when present in high concentrations [56]. However, the wines examined in this study contained low levels of acetaldehyde (<5.05 \(\upmu\)g/mL). Similarly, other aldehydes were detected in low levels, indicating that the variation in their levels among grape cultivars was relatively small compared with that of other volatile compounds. Higher alcohols constitute the largest amount of volatile aromatic compounds in wine and serve as crucial precursors for ester formation [34]. The higher alcohol content in each wine varied significantly among grape cultivars in this study, with isoamyl alcohol and 2-phenylethanol identified as the primary components. These two compounds were most prominently detected in the SM and KN wines, whereas the SB wine showed the lowest levels.