## 3 Results and Discussion
### Identification of Sugars  
Sugar content in fruits depends on the species and variety of the tested samples, but it also depends on the weather conditions and the degree of fruit ripeness. For this reason, different total sugar contents may be determined in fruits of the same species and variety. Depending on maturity degree, there might also be sugars contained.  
Three sugars were determined in the tested samples--fructose, sorbitol, and glucose (Table 3). Studies by other authors confirm the presence of fructose, glucose, and sorbitol in fresh chokeberry fruits [27; 31]. In these studies, the main sugar in chokeberry fruit is glucose and there are slightly  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Variant of Chokeberry**} & **ABTS** & **FRAP** & **Photon Emission** \\ \cline{2-4}  & **\(\upmu\)mole/100 g** & **\(\upmu\)mole/100 g** & **-** \\ \hline C 1e & 126.58 \(\pm\) 2.00 a & 95.53 \(\pm\) 1.10 a & 416.3 \(\pm\) 2.84 a \\ C 2e & 109.85 \(\pm\) 8.08 b & 89.12 \(\pm\) 2.04 b & 402.8 \(\pm\) 3.11 b \\ C 3e & 102.79 \(\pm\) 3.69 c & 78.99 \(\pm\) 2.11 c & 398.7 \(\pm\) 3.00 c \\ C 4c & 92.37 \(\pm\) 2.10 e & 55.05 \(\pm\) 2.08 e & 352.2 \(\pm\) 2.45 e \\ C 5c & 95.83 \(\pm\) 1.54 d & 62.19 \(\pm\) 1.37 d & 367.2 \(\pm\) 2.78 d \\ C 6c & 92.19 \(\pm\) 3.69 e & 54.99 \(\pm\) 2.22 e & 349.9 \(\pm\) 2.29 e \\ \hline \hline \end{tabular}
\end{table}
Table 2: Antioxidant activity and ultra-weak luminescence black chokeberry fruits.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Variant of Chokeberry**} & **Fructose** & **Sorbitol** & **Glucose** & **Sum** \\ \cline{2-4}  & \multicolumn{4}{c}{**g/100 g**} \\ \hline C 1e & 1.54 \(\pm\) 0.04 a & 1.97 \(\pm\) 0.03 f & 2.82 \(\pm\) 0.01 c & 6.33 \\ C 2e & 1.41 \(\pm\) 0.03 b & 3.16 \(\pm\) 0.01 a & 3.36 \(\pm\) 0.03 b & 7.93 \\ C 3e & 0.85 \(\pm\) 0.01 f & 2.20 \(\pm\) 0.02 d & 2.69 \(\pm\) 0.02 d & 5.75 \\ C 4c & 1.16 \(\pm\) 0.01 d & 2.69 \(\pm\) 0.01 c & 1.87 \(\pm\) 0.02 e & 5.73 \\ C 5c & 1.01 \(\pm\) 0.01 e & 2.08 \(\pm\) 0.01 e & 1.92 \(\pm\) 0.01 e & 5.01 \\ C 6c & 1.30 \(\pm\) 0.04 c & 2.90 \(\pm\) 0.02 b & 3.76 \(\pm\) 0.04 a & 7.96 \\ \hline \hline \end{tabular} Mean values with different letters (a–e) within the same row were statistically different (\(p=0.05\)), the same letters form one homogeneous group.  
\end{table}
Table 3: Sugar content in black chokeberry fruits.  
less sorbitol and the least fructose were determined. In studies by other authors [3], sorbitol was not found in fresh fruit, but it was present in chokeberry juice. Studies of [PERSON] et al. [31] also indicated fructose, glucose, and sorbitol sucrose. In the above studies, the highest concentration was sorbitol (6.55-12.99 g/100 g FW), while the content of fructose and glucose was at a similar level (glucose 1.53-3.02 g/100 g FW and fructose 2.2-369 g/100 g FW). A similar analogy was obtained in the studies by [PERSON] et al. [27]. In the cited studies, the content of total sugars was significantly higher (10.26-19.70 g/100 g FW) than in the study below (5.01-7.96 g/100 g FW). This may be due to the selected different varieties and locations of cultivation. Studies were conducted on fruit from Bulgaria, which is characterized by greater sunlight than the regions of Cracow in Poland.