# Quality Characteristics and Antioxidant Activities of Six Types of Korean White Wine
## 3 Results and Discussion
### Antioxidant Activities of Korean White Wine  
Red wine is known to possess a strong antioxidant capacity, which is attributed to the presence of various polyphenic compounds originating from grape skins and seeds [44; 45]. This property serves as a valuable indicator for evaluating the functional quality of wines. In our study, the antioxidant capacity of white wine from each grape cultivar was evaluated based on DPPH, ABTS, and FRAP activities (Figure 3); however, it was not as potent as that in red wine. The VB wine exhibited significantly higher DPPH, ABTS, and FRAP activities than other wines, consistent with the findings of the analysis of total phenolic and flavonoid compounds. [PERSON] et al. (1997) [46] revealed that polyphenic compounds influencing antioxidant activity were more abundant in Vidal grapes than in Chardonnay and Seibel grapes but less abundant in Riesling grapes. Additionally, [PERSON] et al. (2015) compared antioxidant activities of 20 different grape cultivars and demonstrated that red grape cultivars, such as Chasselas Rouge, Red Globe, Delaware, Ruby Seedless, Koo, Hongiseul, and Honey Red, exhibited DPPH activity levels ranging from 48.2 to 87.6 \(\upmu\)g/100 g, FRAP activity levels ranging from 115.0 to 179.0 \(\upmu\)g/100 g, and ABTS activity levels ranging from 11.1 to 39.0 \(\upmu\)g/100 g [47]. In contrast, Vidal grapes displayed relatively lower DPPH, FRAP, and ABTS activity of 34.5, 86.7, and 14.9 \(\upmu\)g/100 g, respectively. However, the Vidal cultivar showed higher antioxidant activity than the commonly cultivated Campbell Early in Korea, which displayed DPPH and FRAP activity levels of 32.8 \(\upmu\)g/100 g and 79.1 \(\upmu\)g/100 g, respectively [47]. This suggests that Vidal grapes exhibit a moderate level of antioxidant capacity among white wines. Our study results highlight that VB, enriched with high polyphenic content relative to other white grape cultivars, demonstrated the most pronounced antioxidant activity.  
Polyphenols and sulfur compounds, which contribute to the antioxidant capacity of wine, are typically more abundant in red wine than in white wine. Nonetheless, recent research has revealed that the antioxidant capacity of Chardonnay wine can be improved by adjusting the contents of amino acids, aromatic compounds, and peptides containing N- and S-compounds through glutathione treatment in the early stages of winemaking [48]. Furthermore, a previous study revealed the role of sulfur compounds in augmenting the radical quenching ability of white wine [49], highlighting the increasing interest in the  
Figure 3: Antioxidant activities of white wines produced using six types of white grapes cultivated in Korea. Different letters within the same column indicate significant differences (\(p<0.05\)).  
wine metabolome. As the mechanisms of antioxidant substances can be classified into two categories--ROS scavengers and transition metal ion chelators, various methods such as ORAC, TRAP, FRAP, CUPRAC, ABTS, and DPPH have been employed to measure antioxidant capacity [50]. The presence of a greater number of procyanidin trimers in Vidal grapes than in other grape cultivars indicate their abundance in phenolic compounds [43], potentially accounting for the relatively higher antioxidant capacity in the VB wine compared with that in other wines in this study.