## 3 Results and Discussion
### Influence of Variety
[45] reported that fructose and glucose levels in high quality wines is low (0.71 \(\pm\) 0.73 and 0.32 \(\pm\) 0.44 g L\({}^{-1}\), respectively), however, in some sweet and sparkling wines fructose and glucose levels can be much higher. [PERSON] et al. [46] reported the mean glucose and fructose contents were less than 1.23 and 4.97 g L\({}^{-1}\). Content of alcohol in wines varied between 11.50 and 13.80% with the mean 12.52%. Mean content of alcohol in chardonnay wines was 12.73 \(\pm\) 0.65%, in pinot blanc 12.46 \(\pm\) 0.21% and in pinot gris 12.37 \(\pm\) 0.82%. The highest content of alcohol was observed in chardonnay from Nitrianska w.r. and the lowest in pinot gris from Malokarpatska w.r.  
White wines typically show lower content of phenolic compounds compared to red ones. The most dominant polyphenols in white wines are hydroxycinamic acid derivatives, hydroxybenzoic acids, flavonoids and flavan-3-ols that are related to wine sensorial properties, such as the chromatic characteristics, colour stability, bitterness and astringency [27]. Our wines presented relatively high values of total polyphenols, ranging from 329 to 403 mg GAE L\({}^{-1}\) for chardonnay, from 283 to 379 mg GAE.L\({}^{-1}\) for pinot blanc and 256 to 381 mg GAE L\({}^{-1}\) for pinot gris wines. The highest content of total polyphenols was found in chardonnay from the Juznoslovenska wine-growing region (403.64 \(\pm\) 9.41 mg GAE L\({}^{-1}\)). In all other chardonnay wine samples, the TPC levels exceeded a content of 300 mg GAE L\({}^{-1}\). In comparison with the chardonnay wines from Montenegro (TPC 226 mg GAE L\({}^{-1}\)) [47], the content in Slovak chardonnay wines was higher in more than 100 mg GAE L\({}^{-1}\). Our results are also in agreement with experiments by [PERSON] et al. [30] and [PERSON] et al. [31], who examined the antioxidant activity, total phenolic and flavonoid contents in monovarietal wines of Welschriesling, chardonnay. According to their results, Slovak white wines were high in polyphenols (average content was 303.2 mg GAE.L\({}^{-1}\) in Welschriesling, resp. 355.6 mg GAE L\({}^{-1}\) in chardonnay). Total antioxidant activity presents one of the important characteristics of wine. In general, a higher level of antioxidants is connected with higher levels of polyphenols. In our study, all wines presented relatively high values for the antioxidant activity, ranged between 51.06 and 72.53% of inhibition of DPPH (average: 63.30% for chardonnay, 58.62% for pinot blanc and 64.45 for pinot gris wines). Our results for antioxidant activity were correlated with previously published data for white wines [30; 31; 48]. According to several studies, polyphenolic compounds have shown a different behaviour towards DPPH free radical, both in terms of capacity and rate of scavenging [49; 50]. The antioxidant activity of phenolic compounds is related with their chemical structure. Higher activity has been reported in the compounds with a high number of hydroxyl groups. The contribution of each polyphenol to the antioxidant activity of wines is different, so the activity of wines depends on their phenolic profile. [PERSON] et al. [50] examined correlation between the several polyphenol compounds and their antioxidant activity. A good positive correlation was observed between antioxidant activity and quercetin content, and rutin and procyanidin B1 showed a reasonable correlation (approx. 0.55). No correlation was found between caftaric acid, the predominant major phenolic compound in wines. In our study, some wine samples showed different trend connected with high TPC values and lower TAA or lower TPC and higher TAA values, what was confirmed in all three batches of wines. A phenolic profile and presence of other kinds of antioxidants in wines was not followed. To quantify the relationship among each of the chemical parameters, Pearson correlation was used. Weak positive correlation was found between TPC and TAA (r = 0.33), glucose and fructose content (r = 0.25) and malic acid and fructose (r = 0.47).