## 3 Results and Discussion
### Chemical Composition of Black and Red Currant Juices
The value of total anthocyanins in our case is calculated as the sum of all anthocyanins, as many authors do [4; 47; 10; 13; 14; 44]. In some studies, it is calculated as the equivalent of cyanidin-3-glucose [8; 13; 33], but this can be assumed to underestimate the results, because Cy-3-glu is one of the least abundant anthocyanins in black current [13]. Student's \(t\)-test revealed significant differences (\(p<0.01\)) in the anthocyanin profile of black current juices depending on different treatments (E/WE) for two anthocyanins, Dp-3-glu and Cy-3-glu, and significant differences (\(p<0.05\)) for Dp-3-rut (Table 4). In contrast, Student's \(t\)-test showed no significant differences (\(p>0.05\)) in the anthocyanin content of BC juices depending on the year of harvest. The total amount of anthocyanins (TACy) and the content of individual anthocyanins (except Cy-3-rut) are approximately 1.5 times higher in enzyme juice samples than in non-enzyme juices. Anthocyanins are more abundant in the skin than in the flesh, so enzyme preparations are used to release them [8; 38]. Student's \(t\)-test showed no significant differences (\(p>0.05\)) in the anthocyanin content of RC juices depending on the year of harvest or different processes. The cut-off values for RC 2020/2021 were for Cy-3-rut (\(p=0.068\)). The PCA analysis (Figures 2 and 3) shows the relationship between chemical composition and the year of harvest (2020/2021) and technological processing (E/WE). For blackcurrent, the distribution of the PCA analysis was within minerals against other markers, and for red currant, sugars and ash were selected. For red currant juices, 16 chemical \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Black Currant (BC)**} & \multicolumn{2}{c}{**Student’s**} \\
**Marker** & **E** & **WE** & **Literature** & **\(t\)-Test** & **Reference** \\  & **(\(n=16\))** & **(\(n=6\))** & **Data** & **\(p\)-Values** & **\(p\)-Values** \\ \hline Dp-3-glu & & & & & \\ (“Cy-3-glu) & & & & & \\ Dp-3-rut & 243.6 \(\pm\) 89.5 b & 151.1 \(\pm\) 61.9 a & 11.5–311.4 & \(<\)0.05 & [4;10,11; 13; 14; 36; 38; 40; 44; 44; 45; 46; 47; 48] \\ Cy-3-glu & & & & & \\ Cy-3-rut & 117.9 \(\pm\) 49.0 & 102.8 \(\pm\) 50.7 & 11.4–211.4 & NS & [4;10,11; 13; 14; 36; 38; 40; 44; 45; 46; 47; 48] \\ Sum of unknown & nd & nd & 0.0–14.4 & - & [10; 38; 40; 45; 46; 47; 48] \\ TACy* & 411.9 \(\pm\) 140.7 & 284.1 \(\pm\) 117.7 & 29.4–586.6 & NS & [4; 6; 8; 10; 11; 13; 14; 28; 33; 36; 38; 40; 44; 45; 47; 48] \\ \hline  & \multicolumn{2}{c}{Red currant (RC)} & \multicolumn{2}{c}{Student’s} \\ Marker & E & WE & Literature data & \(t\)-test & Reference \\ (\(n=10\)) & (\(n=6\)) & & & \(p\)-Values & \\ \hline Dp-3-glu & & & & \\ (“Cy-3-glu) & nd & nd & 0.0–0.2 & - & [10; 38; 45; 46; 47] \\ Dp-3-rut & nd & nd & \(\prec\)LOD & - & [10; 38; 45; 46; 47] \\ Cy-3-rut & 20.7 \(\pm\) 8.0 & 20.9 \(\pm\) 4.6 & 0.2–28.9 & NS & [10; 38; 45; 46; 47; 49] \\ Cy-3-rut & 10.2 \(\pm\) 4.4 & 10.0 \(\pm\) 3.5 & 1.6–17.5 & NS & [10; 38; 45; 47; 49] \\ Sum of unknown & 11.9 \(\pm\) 10.1 & 5.1 \(\pm\) 2.2 & 0.0–12.5 & NS & [10; 38; 46; 47] \\ (“Cy-3-glu) & & & & & \\ TACy* & 42.8 \(\pm\) 14.3 & 36.1 \(\pm\) 7.1 & 4.7–31.7 & NS & [2; 10; 33; 38; 39; 47] \\ \hline  & \multicolumn{2}{c}{Note: Data are presented as mean \(\pm\) SD; \(n=\) number of samples. * The concentration of delphinidin-3-rutinoside and sum of unknown anthocyanin were calculated using a calibration series from the cyanidin-3-glucoside standard; the total anthocyanins (TACy) were calculated as the sum of all anthocyanins. nd = not detected. SDs followed by a different lowercase letter in a row are significantly different (\(p<0.05\)), as analysed by Student’s \(t\)-test. NS = not significant.} \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Anthocyanin content [mg/100 g.f.w.] in BC and RC juices (E/WE). compounds were used for the PCA analysis, as no sucrose was detected (<0.1 g/kg) in RC juices.