## 3 Results
### Organic Acids and Sugars  
Citric acid, followed by quinic acid, was the predominant organic acid in black currant berries, whereas, in sea buckthorn, malic acid was predominant, followed by quinic acid. The results of studies on the effect of freeze-drying on the content of organic acids and carbohydrates of berries after freeze-drying are shown in Table 3.  
It was found that the level of organic acids in the studied samples of fresh black currant berries were: citric acid--3181 mg/100 g, quinic acid--1500.3 mg/100 g, malic acid--515.23 mg/100 g, and tartaric acid--63.56 mg/100 g; the data obtained are consistent with earlier studies by [PERSON] and [PERSON] [28]. The levels of organic acids observed in our studies in sea buckthorn berries were close to those determined earlier by [PERSON] et al. [29], for example, the content of malic acid was 3542.2 mg/100 g, quinic acid was 1764.5 mg/100 g, citric acid was 133.33 mg/100 g, and tartaric acid was 4.96 mg/100 g [29]. It was found that the freezing time of the berries slightly reduces the level of organic acids in the finished product. Thus, in the black currant berry, from the initial content in the fresh berry, the content of citric acid decreased by 15.57% and 16.47%, respectively, at sublimation times of 18 h and 20 h. However, at a sublimation duration of 22 h, a sharp decrease in the citric acid content was observed, which was 34%. A similar decrease was observed for malic acid, so at 18, 20, and 22 h its content was 18.2, 19.7, and 34.5%, respectively. The reduction levels of quinic acid (5%) and tartaric acid (10%) in black currant berries during a drying process lasting 22 h were insignificant. Similarly, for sea buckthorn berries, the highest level of the reduction of citric acid was determined with a freeze-drying process duration of 22 h and was 39%, and for malic and \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Name** & **Citric Acid** & **Malic Acid** & **Quinic Acid** & **Tartary Acid** & **Sacrose** & **Glucose** & **Fructose** \\ \hline  & & & Black currant & & & & \\ \hline Fresh & 3181.0 \(\pm\) 113.503* & 515.23 \(\pm\) 72.797 d & 1500.3 \(\pm\) 0.176 b & 63.500 \(\pm\) 0.185* & 1.8500 \(\pm\) 0.029* & 16.600 \(\pm\) 0.058* & 25.667 \(\pm\) 0.067 a \\
18 h & 2685.7 \(\pm\) 94.669 b & 421.40 \(\pm\) 60.142 d & 1445.2 \(\pm\) 0.057* & 58.000 \(\pm\) 0.149 b & 1.4700 \(\pm\) 0.012 b & 13.777 \(\pm\) 0.015 b & 21.257 \(\pm\) 0.018 b \\
20 h & 2657.2 \(\pm\) 76.302 b & 413.83 \(\pm\) 51.842 d & 1456.2 \(\pm\) 0.145* & 57.500 \(\pm\) 0.153 b & 1.4167 \(\pm\) 0.009 c & 137.243 \(\pm\) 0.019 b & 21.167 \(\pm\) 0.015 b \\
22 h & 2101.4 \(\pm\) 103.308 e & 337.23 \(\pm\) 73.627 e & 1429.4 \(\pm\) 0.14 & 56.000 \(\pm\) 0.150 & 1.4135 \(\pm\) 0.020 e & 13.650 \(\pm\) 0.021 c & 21.135 \(\pm\) 0.023 e \\ \hline  & & & & & & & \\ \hline  & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Effect of freeze-drying on the content of organic acids and sugars in black currant and sea buckthorn berries, mg/100 g dry matter. tartaric acids, was about 14-20%. [PERSON] et al. found that in sea buckthorn berries, the concentrations of malic and citric acids tend to decrease during osmotic dehydration and subsequent air drying, reaching reductions of up to 60-70% in some cases compared to the control samples [61]. Studies on the effect of freeze-drying on the sugar content showed that the main carbohydrates detected in the analyzed berry species were glucose, fructose, and sucrose, which is consistent with the data found by [PERSON] et. al. [62], [PERSON] et. al. [63], and [PERSON] [64]. According to the experiments conducted, it was found that fresh black current berries have a higher content of carbohydrates than sea buckthorn berries.