## 3 Results and Discussion
### Chemical Composition of Black and Red Currant Juices
The average values of potassium are at the lower CoP limit, which may be due to the maturity level of the berries. [PERSON] et al. [29] investigated the mineral content of currants and measured potassium concentrations of 1711-1867 mg/kg for black currant. The high variability of the results limits the applicability of the standard values given in the CoP for black currant; therefore, the values (especially for mineral substances) might have been updated or reevaluated. The Code of Practice does not define the chemical composition (limit values) of red currant juice, so the values are compared with the range given in the food composition and nutrition tables for red currants ([PERSON] et al., 2015) [30]. Contrary to our results, [PERSON] et al. (2015) reported the standard value of the chemical composition for red currant juice: 0.9-5.0 g/kg for sucrose, 7.3-29.0 g/kg for glucose, 18.7-30.0 g/kg for fructose, 2.4-6.4 g/kg for malic acid, 16.9-23.0 g/kg for citric acid, and 260-470 mg/kg for ascorbic acid [30]. On the other hand, consistent with our results for sugars and organic acids are the published results from [PERSON] and [PERSON] (2005 and 2006a), [PERSON] et al. (2011), and [PERSON] et al. (1986) [31; 32; 33; 34]. Compared to black currants, red currant varieties are highly variable in malic acid (0.6-11.4 g/kg) and potassium (466-3493 mg/kg) content. The average values of mineral substances correspond to the values given in the nutritional tables [30]. Similar results for phosphorus and potassium content in six different red currant varieties were documented by [PERSON] et al. (2016) [35]. A lower ash content may indicate increased water content and decreased mineral content due to climatic conditions or natural variability. Titratable acidity and citric acid decrease rapidly during maturation and react to climatic factors like high temperatures. Different type of cultivation soils and regional climates might affect mineral composition. The content of sugars, organic acids, formed number, mineral substances, and anthocyanins can be highly variable and influenced by several factors: climatic conditions (temperature, day length, UV irradiation, pH), natural variability in cultivars, ripeness level, latitude, technological processing, and storage conditions [10; 12; 31]. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Marker**} & \multicolumn{2}{c}{**Black Cumant (BC)**} & \multicolumn{2}{c}{**Red Cumant (BC)**} & \multicolumn{2}{c}{**ANOVA**} & \multicolumn{2}{c}{**Literative Data**} & \multicolumn{2}{c}{**Reference**} \\ \multicolumn{1}{c}{**\(\mathbf{\boldsymbol{\
u}}\)**} & \multicolumn{2}{c}{**VVE**} & \multicolumn{2}{c}{**E**} & \multicolumn{2}{c}{**VVE**} & \multicolumn{2}{c}{**VVE**} & \multicolumn{2}{c}{**BC**} & \multicolumn{2}{c}{**BC**} & \multicolumn{2}{c}{**BC**} \\ \hline \multicolumn{1}{c}{} & \multicolumn{1}{c}{**(\(\mathbf{\boldsymbol{\
u}}\) 10)**} & \multicolumn{1}{c}{**(\(\mathbf{\boldsymbol{\
u}}\) 0)**} & \multicolumn{1}{c}{**(\(\mathbf{\boldsymbol{\
u}}\) 10)**} & \multicolumn{1}{c}{**(\(\mathbf{\boldsymbol{\
u}}\) 10)**} \\ \hline Subrule  
The anthocyanin content (f.w.) of BC and RC juices is presented in Table 4 and Figure 4. In agreement with other studies on BC juices, the four main anthocyanins, delphinidin-3-glucoside (Dp-3-glu), delphinidin-3-rutinoside (Dp-3-rut), cyanidin-3-glucoside (Cy-3-glu), and cyanidin-3-rutinoside (Cy-3-rut), were identified (see Table 4). Other authors found trace amounts of petunidin, peonidine, pelargonidine, cyanidin, delphinidin, and malvinidine derivatives. The HPLC analysis revealed 3-5 peaks in RC juices. According to the standard, the retention time and spectra characteristics of Cy-3-glu and Cy-3-rut were confirmed (RC, Table 4). Other peaks of unknown anthocyanins in RC could probably be cyanidin-3-sophoroside, cyanidin-3-glucosyl-rutinoside, cyanidin-3-xylosyl-rutinoside, and cyanidin-3-sambubioside [13; 45; 46].