## 3 Results
### Vitamins
Freeze-drying berries at 50 \({}^{\circ}\)C with a process duration of 18 h  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Name** & **B1** & **B2** & **B6** & **B3** & **B5** & **C** & **E** & **A** \\ \hline \multicolumn{8}{c}{Black currant} \\ \hline Fresh & 0.0710 \(\pm\) 0.0006\({}^{\circ}\) & 0.0540 \(\pm\) 0.0012\({}^{\circ}\) & 0.0273 \(\pm\) 0.0007\({}^{\circ}\) & 0.3637 \(\pm\) 0.0120\({}^{\circ}\) & 0.3467 \(\pm\) 0.0088\({}^{\circ}\) & 2940.00 \(\pm\) 0.0012\({}^{\circ}\) & 73.670 \(\pm\) 0.0088\({}^{\circ}\) & 168.30 \(\pm\) 0.0008\({}^{\circ}\) & 168.30 \(\pm\) 0.0008\({}^{\circ}\) & 167.370 \(\pm\) 0.0008\({}^{\circ}\) & 169.370 \(\pm\) 0.0007\({}^{\circ}\) \\
18 h & 0.0467 \(\pm\) 0.0012\({}^{\circ}\) & 0.0433 \(\pm\) 0.0009\({}^{\circ}\) & 0.0212 \(\pm\) 0.0006\({}^{\circ}\) & 0.2867 \(\pm\) 0.0088\({}^{\circ}\) & 0.2633 \(\pm\) 0.0008\({}^{\circ}\) & 163.03 \(\pm\) 0.0015\({}^{\circ}\) & 57.800 \(\pm\) 0.0008\({}^{\circ}\) & 137.70 \(\pm\) 0.0007\({}^{\circ}\) \\
20 h & 0.0630 \(\pm\) 0.0027\({}^{\circ}\) & 0.0370 \(\pm\) 0.0012\({}^{\circ}\) & 0.0167 \(\pm\) 0.0019\({}^{\circ}\) & 0.2700 \(\pm\) 0.0015\({}^{\circ}\) & 0.2167 \(\pm\) 0.0008\({}^{\circ}\) & 161.70 \(\pm\) 0.0009\({}^{\circ}\) & 56.300 \(\pm\) 0.0088\({}^{\circ}\) & 131.370 \(\pm\) 0.0005\({}^{\circ}\) \\
22 h & 0.0613 \(\pm\) 0.0009\({}^{\circ}\) & 0.0343 \(\pm\) 0.0009\({}^{\circ}\) & 0.0130 \(\pm\) 0.0012\({}^{\circ}\) & 0.2233 \(\pm\) 0.0120\({}^{\circ}\) & 0.1767 \(\pm\) 0.0088\({}^{\circ}\) & 161.00 \(\pm\) 0.0012\({}^{\circ}\) & 51.330 \(\pm\) 0.0003\({}^{\circ}\) & 127.700 \(\pm\) 0.0008\({}^{\circ}\) \\ \hline \multicolumn{8}{c}{Sba budthorn} \\ \hline Fresh & 0.0350 \(\pm\) 0.0006\({}^{\circ}\) & 0.0577 \(\pm\) 0.0009\({}^{\circ}\) & 0.0289 \(\pm\) 0.0006\({}^{\circ}\) & 0.4727 \(\pm\) 0.0018\({}^{\circ}\) & 0.1497 \(\pm\) 0.0015\({}^{\circ}\) & 196.300 \(\pm\) 0.0009\({}^{\circ}\) & 25.270 \(\pm\) 0.0020\({}^{\circ}\) & 249.300 \(\pm\) 0.0018\({}^{\circ}\) \\
18 h & 0.0280 \(\pm\) 0.0012\({}^resulted in a 20% decrease in vitamin C in black currant and sea buckthorn berries. Further increasing the time of the sublimation process reduces the level of vitamin C insignificantly by 1% in both berries. This can be explained by the fact that the sublimation process is carried out in a vacuum at low temperatures, thereby preserving the level of ascorbic acid [43,58]. According to the research by [PERSON] et al. [59], the content of ascorbic acid in sea buckthorn berries decreased by 45.39%, 53.81%, 74.23%, 77.09%, and 79.93% after vacuum freeze-drying (VFD), pulse-vacuum drying (PVD), infrared drying (IRD), infrared-assisted hot air drying (IR-HAD), and hot air drying (HAD), respectively, compared to fresh samples. The research findings confirm that minimal losses of vitamin C are observed during the freeze-drying of berries. The results obtained are in line with [PERSON] al. [60] where, for papaya and guava, the preservation of vitamin C after freeze-drying was 88 and 63%, respectively. Thus, it was found that the preservation of the total vitamin content after freeze-drying at a 50 \({}^{\circ}\)C temperature, and a duration of 18 and 20 h on average is about 80%. However, increasing the freeze-drying time over 20 h is not recommended, as then there is a sharp decrease in the vitamin content.