## 3 Results and Discussion
depending on the grape cultivar. Vitamin C is the vitamin most sensitive to physical and chemical factors such as heat, exposure to oxygen, and the Maillard reaction. There was no correlation between the contents of total soluble solids and vitamin C in the tested grapes. The polyphenol content in plant raw materials is very important for nutritional reasons. The greater the share of polyphenols in the raw material, the greater the potential of the finished product. Therefore, this ingredient should be tested in all raw materials that are intended for processing. The total polyphenol content of the tested grape cultivars ranged from 661.1 to 2041.1 uM GEA\(\cdot\)100 g\({}^{-1}\) f.m. (Table 3). The highest content was found in 'Chardonnay' grapes, while the lowest was found in grapes of the 'Bacchus' cultivar. A study by [PERSON] et al. [21] reported a similar total polyphenol content (780-2050 uM GEA\(\cdot\)100 g\({}^{-1}\) f.m.) in four grape cultivars grown in Turkey. Most of the results reported in the literature concern the analysis of grape skins. Grape skins have a higher polyphenol content and antioxidant activity than grape pulp [23; 24]. The antioxidant activity varied among the different grape cultivars (Table 3), which is due to the different compositions of specific cultivars, which lead to different responses for antioxidant activity. The fruits of the 'Bacchus' cultivar statistically had the lowest total polyphenol content and the lowest FRAP (Table 3). The highest DPPH activity was recorded in 'Chardonnay' grapes, and the highest ABTS and FRAP activities were found in 'Johanniter' grapes. The literature data [25; 26] indicate that polyphenols play an important role in antioxidant activity and, in particular, in scavenging DPPH. The grape cultivars included in this study contained a varied concentration of macronutrients, even though they were grown on the same soil. The grapes of 'Souvignier gris'--pink berries--accumulated the most magnesium and calcium, while phosphorus and potassium were highest in 'Bacchus' grapes (Table 4). The grapes of 'Souvignier gris' also contained significant amounts of potassium but had the least amount of phosphorus. \begin{table}
\begin{tabular}{c c c c c} \hline \multirow{2}{*}{**Cultivar**} & **Polyphenols** & **ABTS \({}^{*}\)** & **FRAP \({}^{*}\)** \\  & **[μM GAE\(\cdot\)100 g\({}^{-1}\) f.m.]** & **DPPH \({}^{*}\)** & **[μMTrolox\(\cdot\)100 g\({}^{-1}\) f.m.]** & **FRAP \({}^{*}\)** \\ \hline ‘Chardonnay’ & 2041.4 \(\pm\) 119.79 a & 547.9 \(\pm\) 52.37 a & 3143.7 \(\pm\) 171.40 b & 398.6 \(\pm\) 31.95 d \\ ‘Bacchus’ & 661.1 \(\pm\) 48.09 e & 435.2 \(\pm\) 41.72 c & 2637.2 \(\pm\) 99.50 d & 207.7 \(\pm\) 12.58 e \\ ’Johanniter’ & 1777.5 \(\pm\) 108.2 b & 535.5 \(\pm\) 32.84 a & 4578.9 \(\pm\) 201.90 a & 622.9 \(\pm\) 62.98 a \\ ‘Muscaris’ & 908.4 \(\pm\) 96.21 d & 513.2 \(\pm\) 52.16 b & 2800.7 \(\pm\) 176.10 c & 512.6 \(\pm\) 517.76 c \\ ‘Solaris’ & 920.7 \(\pm\) 89.67 d & 380.6 \(\pm\) 21.26 d & 2555.8 \(\pm\) 101.70 d & 548.3 \(\pm\) 52.58 b \\ ‘Souvignier gris’ & 1484.9 \(\pm\) 100.0 c & 537.8 \(\pm\) 44.76 a & 4491.6 \(\pm\) 121.20 a & 562.3 \(\pm\) 54.25 b \\ \hline \end{tabular}  
* ABTS. 2.2’-azino-bis-3-ethylbenzothicad; FRAP. ferric reducing antioxidant potential; DPPH. radical scavenging activity; Mean values with different letters (a–e) within the same column are statistically different (\(p=0.05\)). Values expressed as mean \(\pm\) standard deviation.  
\end{table} 
Table 3: Total polyphenol content and antioxidant activity of six cultivars of white whole grape berries.