# Quality Characteristics and Antioxidant Activities of Six Types of Korean White Wine
## 3 Results and Discussion
### Volatile Aromatic Compounds in Korean White Wines
In the analysis of volatile ester compounds, PC1 and PC2 explained 44.59% and 25.37% of the variance, respectively. Several ester compounds were closely associated with the CB, SB, and CS wines, which exhibited higher total ester contents compared to the other wines. Specifically, ethyl acetate, propyl acetate, isobutyl acetate, ethyl butanoate, isoamyl acetate, ethyl lexanoate, hexyl acetate, ethyl octanoate, isobutylanoate, methyl salicate, and 2-phenylethylly acetate were significant contributors to the SB and CS wines. The CB wine was notably influenced by isoamyl hexanoate, ethyl nonanoate, ethyl decanoate, isopentyl octanoate, and ethyl 9-hexadecenoate. Ethyl heptanoate and ethyl 4-hydroxybutanoate had an impact on the SM wine, while ethyl isobutyrate and ethyl 9-decenoate were relevant to the VB wine. Lastly, the KN wine demonstrated associations with ethyl propanoate, ethyl 2-hexenoate, and ethyl hexadecanoate. In the analysis of monoterpene compounds, PC1 and PC2 explained 40.56% and 33.94% of the variance, respectively. The loadings were found to be closely associated with the CS and KN wines, which contained higher levels of monoterpene compounds. This suggests that volatile monoterpene compounds played a significant role in influencing the sensory characteristics of these two wines compared to the other wines. Specifically, p-cymene, 4-terpineol, \(\beta\)-citronello, and geraniol were significant contributors to the aroma profile of the CS wine. However, terpinolene, nerol, linalool, and \(\alpha\)-terpineol were influential in shaping the aroma of the KN wine. The other wines were not significantly impacted by monoterpenes, based on the PCA analysis. Figure 4: Biplots of variable loadings and principal component scores from the principal component analysis (PCA) of volatile ester (**left**, 1–30) and monoterpene (**right**, 31–38) compounds. Numbers represent the following compounds: 1, ethyl acetate; 2, ethyl propanoate; 3, ethyl isobutyrate; 4, propyl acetate; 5, isobutyl acetate; 6, ethyl butanoate; 7, isoamyl acetate; 8, isopentyl propanoate; 9, ethyl hexanoate; 10, hexyl acetate; 11, ethyl heptanoate; 12, ethyl 2-hexenoate; 13, heptyl acetate; 14, ethyl octanoate; 15, isoamyl hexanoate; 16, ethyl nonanoate; 17, isobutyl octanoate; 18, ethyl decanoate; 19, isopentyl octanoate; 20, diethyl succinate; 21, ethyl 9-decenoate; 22, isobutyl decanoate; 23, methyl salicate; 24, ethyl 4-hydroxybutanoate; 25, 2-phenylethylly acetate; 26, ethyl dodecanoate; 27, isoamyl decanoate; 28, ethyl hexadecanoate; 29, ethyl 9-hexadecenoate; 30, ethyl octadecenoate; 31, terpinolene; 32, nerol; 33, p-cymene; 34, linalool; 35, 4-terpineol; 36, \(\alpha\)-terpineol; 37, \(\beta\)-citronello; 38, geraniol. \begin{table}
\begin{tabular}{l l l l l l l l l l l} \hline \hline
**Compounds** & **Odor Description** & **Threshold** & \multicolumn{3}{c}{**Unified**} & \multicolumn{3}{c}{**Vehicle Aromatic Compounds (ng/ml)**} & \multicolumn{3}{c}{**CS**} & \multicolumn{3}{c}{**SM**} & \multicolumn{3}{c}{**SS**} & \multicolumn{3}{c}{**NN**} & \multicolumn{3}{c}{**CS**  
\begin{table}
\begin{tabular}{l c c c c c c c c c} \hline \hline
**Compounds** & **Odor Description** & **Threshold** & **OAV** & \multicolumn{5}{c}{**Volatile Amoustical Compounds (log/ml)**} \\ \cline{4-9}  & **Odor Description** & **(log/U)** & **CS** & **SM** & **SS** & **NN** & **VR** & **CS** \\ \hline \multicolumn{9}{l}{**Ester**} \\ \multicolumn