## 3 Results and Discussion  
All grapes were harvested at the agrotechnical date at which the wine was planned to be produced. All grape cultivars were characterized by a high dry matter content, resulting in notable quantities of waste in the winemaking process (Table 2). This may also indicate that the grapes were harvested too early. The grapes of Bacchus and Chardonnay were characterized by a lower dry matter content due to their soft and thinner skins. This was previously confirmed by [PERSON] et al. [4], showing that the skins of hybrid cultivar grapes are thicker than _V. vinifera_ skins, which contributes to their increased resistance to disease. The content of the total soluble solids for each individual trial was sufficient for allocating these grapes for wine making, except for 'Bacchus' and 'Chardonnay', both of which would require chaptalization (Table 2). The highest level of total soluble solids was found in the 'Solaris' grape variety, which is characterized by its adaptation to the cool climate and early harvesting date. 'Muscaris' grapes accumulated slightly lower sugars, labeled as total soluble solids, whereas 'Johanniter' and 'Souvignier gris' had similar sugar contents. Similarly, in the research of [PERSON] et al. [4], 'Solaris' and 'Muscaris' grapes tended to accumulate more sugar than the 'Johanniter' and 'Souvignier gris' grapes. The values obtained by [PERSON] et al. [20] support this investigation but have not been statistically confirmed. No correlation was found between the quantity of total soluble solids and vitamin C and acidity in the test trials, indicating the different nature of the selected cultivars. However, the acidity of the hybrid cultivars was higher than in [PERSON] et al. [4] and the three-year averages in [PERSON] et al. [20], while the reaction pH was lower. The vitamin C content, determined as the ascorbic acid content in the grape cultivars tested, was low. This ingredient is an important antioxidant, and its content is important both in the raw materials and the products. The highest concentration of ascorbic acid was found in 'Chardonnay' (1.36 mg\(\cdot\)100 g\({}^{-1}\) f.m. ), and the lowest was found in 'Johanniter' (0.86 mg\(\cdot\)100g\({}^{-1}\) f. m.), as shown in Table 2. In a studies by [PERSON] et al. [21], the vitamin \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Cultivar** & **Dry Matter\%** & \begin{tabular}{c} **Total Soluble** \\ **Solids**\({}^{\circ}\)**Brix** \\ \end{tabular} & **pH** & \
\begin{tabular}{c} **Total Acidity** \\ **g\(\cdot\)100 g\({}^{-1}\)** * \\ \end{tabular} &
\begin{tabular}{c} **Vitamin C** \\ **mg\(\cdot\)100 g\({}^{-1}\) f.m.** \\ \end{tabular} \\ \hline ‘Chardonnay’ & 33.35 \(\pm\) 1.76 c & 17.6 \(\pm\) 1.26 d & 2.71 \(\pm\) 0.08 b & 0.72 \(\pm\) 0.08 c & 1.36 \(\pm\) 0.10 a \\ ‘Bacchus’ & 32.99 \(\pm\) 1.95 d & 15.7 \(\pm\) 0.99 e & 2.64 \(\pm\) 0.06 a & 0.56 \(\pm\) 0.09 d & 1.10 \(\pm\) 0.09 b \\ ‘Johanniter’ & 36.06 \(\pm\) 2.98 a & 20.3 \(\pm\) 1.72 c & 2.93 \(\pm\) 0.06 c & 0.93 \(\pm\) 0.10 a & 0.86 \(\pm\) 0.09 d \\ ‘Muscaris’ & 33.23 \(\pm\) 4.25 c & 22.0 \(\pm\) 2.16 b & 2.92 \(\pm\) 0.04 c & 0.94 \(\pm\) 0.09 a & 1.18 \(\pm\) 0.09 b \\ ‘Solaris’ & 34.11 \(\pm\) 2.58 b & 23.0 \(\pm\) 2.31 a & 2.96 \(\pm\) 0.05 d & 0.83 \(\pm\) 0.09 b & 0.96 \(\pm\) 0.08 c \\ ‘Souvignier gris’ & 35.56 \(\pm\) 2.58 a & 20.8 \(\pm\) 1.04 c & 2.93 \(\pm\) 0.04 c & 0.85 \(\pm\) 0.09 b & 0.93 \(\pm\) 0.09 c \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Dry matter content, total soluble solids, pH, acidity, and vitamin C of grape samples. C content was 10 times higher (13.67 to 15.55 mg 100 g\({}^{-1}\) f.m.) in grapes cvs. 'Aplhonse Lavalle', 'Red Globe', 'Trakya Ilkeren', and 'Buca Razaikis'. Such a difference may result from the differences in cultivars and harvest date as well as the methods used to determine vitamin C. In a study conducted by [PERSON] [22], the vitamin C content in grapes grown in Turkey was slightly higher than the vitamin C levels reported in this study (1.54-5.77 mg\(\cdot\)100 g\({}^{-1}\) f.m.)