## 3 Results and Discussion
### Total Polyphenol and Anthocyanin Content and the Antioxidant Activity  
Results of phenolic compound content and the antioxidant activity of table grape skins were shown in Table 2. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Color Coordinates**} & \multicolumn{5}{c}{**Table Grape Varieties**} \\ \cline{2-6}  & **Autumn Royal** & **Black Magic** & **Red Globe** & **Red Globe (Pink)** & **Palieri** \\ \hline L* & 47.76 \(\pm\) 1.20 d & 48.35 \(\pm\) 0.46 d & 62.11 \(\pm\) 0.74 b & 70.92 \(\pm\) 0.87 a & 53.00 \(\pm\) 0.53 c \\ a* & 12.14 \(\pm\) 0.31 c & 12.62 \(\pm\) 0.43 b & 16.22 \(\pm\) 0.10 a & 5.26 \(\pm\) 0.10 d & 12.65 \(\pm\) 0.34 b \\ b* & \(-\)1.35 \(\pm\) 0.18 e & \(-\)0.43 \(\pm\) 0.13 d & 4.08 \(\pm\) 0.25 b & 10.92 \(\pm\) 0.24 a & \(-\)0.05 \(\pm\) 0.05 c \\ C* & 12.22 \(\pm\) 0.32 c & 12.63 \(\pm\) 0.43 b & 16.73 \(\pm\) 0.09 a & 12.12 \(\pm\) 0.22 c & 12.65 \(\pm\) 0.34 b \\ h (\({}^{\circ}\)) & 353.66 \(\pm\) 0.76 c & 358.05 \(\pm\) 0.58 b & 14.12 \(\pm\) 0.89 e & 64.31 \(\pm\) 0.68 d & 359.8 \(\pm\) 0.24 a \\ \hline \hline \end{tabular} a  
\end{table} 
Table 1: Color parameters of table grape skins. The range of TPC in grape skins was 2.58-8.37 mg GAE/g FW (fresh weight), with the highest content found in the Black Magic variety and the lowest in the Red Globe pink variety. Similar results have been previously reported by [PERSON] et al. [5] for skins of some red grape varieties (99-169 mg GAE/100 g FW). TPC value for Autumn Royal, provided by [PERSON] et al. [20], was 118 mg GAE/100 FW, which was significantly lower than TPC observed in our study (7.13 mg GAE/g DW = 169 mg GAE/100 g FW) but the final result was shown by the authors for the whole berries, not for skins. TPC values obtained by [PERSON] et al. [21] for grape skins were in a wide range from 7.94 to 44.64 mg GAE/g DW. The lowest TPC value appeared for the Euro-American hybrid [21], which was similar to the TPC of the Black Magic variety from our study (Table 2). [PERSON] et al. [22] reported 3.5 times lower TPC in skins of the Red Globe variety (456.3 mg GAE/kg FW) in comparison to our results (6.77 mg GAE/g DW = 1529 mg GAE/kg FW). In this study, ACN content varied from 0.10 mg Cyglu/g DW for the Red Globe pink variety to 5.83 mg Cyglu/g DW for the Autumn Royal variety. Since ACNs are responsible for the color of red grape varieties, dark-colored grapes contained the highest content of these compounds, which was also observed by [PERSON] et al. [19]. The antioxidant activity (DPPH) of table grapes ranged in a wide range from 32 to 90 \(\upmu\)mol/g DW. Among the varieties, Black Magic and Red Globe showed the highest antioxidant activity, whereas the lowest was determined for Red Globe pink. Similar results were shown by [PERSON] et al. [21] and [PERSON] et al. [5] for some red varieties cultivated in Europe and America, [PERSON] et al. [22] for the Red Globe variety. Whereas [PERSON] et al. [20] reported two times lower radical scavenging activity for the Autumn Royal variety (172 mg TE/100 g FW) in comparison to our results (62.21 \(\upmu\)mol TE/g DW = 369 mg TE/100 g FW). Since the antioxidant activity has been previously reported to be significantly correlated with the phenolic compounds [5; 19; 20], the correlation coefficients were calculated. Generally, the higher the content of phenolic acids and polyphenols, the higher antioxidant activity was. In our study, the correlation coefficient (R Spearman) between DPPH and TPC values was 0.736 (\(p\) = 0.000), whereas between DPPH and ACN was only 0.282, but it was statistically significant (\(p\) = 0.047). Although among all varieties, Autumn Royal was characterized by the highest ACN content (5.83 mg Cyglu/g DW) and high TPC value (7.13 mg GAE/g DW), its antioxidant activity was similar to the antioxidant activity of the Pallieri variety and lower in comparison to the Red Globe, showing ACN equaled to 1.25 mg Cyglu/g DW and TPC equaled to 6.77 mg GAE/g DW.