## 3 Results  
### Sensory Evaluation and Moisture Content  
The main indicator determining the quality of freeze-dried berries is the sensory evaluation of the finished product, which depends on parameters such as the shelf temperature and the duration of freeze-drying. Shelf temperature has an effect on the freeze-drying time, the higher the temperature, the less time it takes to dry, but higher temperatures can also worsen the organoleptic performance of the final product, which is consistent with the research by [PERSON] et al. [56]. The sensory evaluation unveiled that both black currant and sea buckthorn berries exhibited a pronounced moisture content and an unattractive appearance when subjected to freeze-drying at shelf temperatures of 35 \({}^{\circ}\)C, 40 \({}^{\circ}\)C, and 45 \({}^{\circ}\)C, with durations of 18, 20, and 22 h. Similarly, this effect was observed at a shelf temperature of 35 \({}^{\circ}\)C with a freeze-drying time of 24 h. Berries subjected to freeze-drying at a shelf temperature of 55 \({}^{\circ}\)C, with durations of 18, 20, and 22 h, as well as at shelf temperatures of 40 \({}^{\circ}\)C, 45 \({}^{\circ}\)C, and 50 \({}^{\circ}\)C, with a freeze-drying time of 24 h, also exhibited an unappealing appearance, a bitter taste, and increased fragility. Furthermore, sea buckthorn berries displayed a dark color. Through a sensory assessment, the optimal drying temperature for both berry types were determined to be a shelf temperature of 50 \({}^{\circ}\)C for durations of 18, 20, and 22 h. The results of this sensory evaluation are depicted in Figure 1.  
The texture of the freeze-dried samples from both black currant and sea buckthorn, freeze-dried at a shelf temperature of 35 \({}^{\circ}\)C for a duration of 18 h, was lower in sea buckthorn, measuring seven points. However, the appearance and aroma scores were lower in black currant, at 5.8 and 7.0 points, respectively. This disparity could be attributed to the elevated moisture content of the berries--black currant samples registered 72.3%, while sea buckthorn samples showed an 83.27% moisture content (refer to Table 1). The samples exhibited increased stickiness and a wrinkled appearance. At a shelf temperature of 40 \({}^{\circ}\)C, the taste and aroma scores were also lower: black currant samples scored 6.8 and 6.7 points, respectively. As it was subjected to a shelf temperature of 45 \({}^{\circ}\)C with a duration of 18 h, the lowest flavor score of 6.6 points was recorded for the black currant samples, as well as for the appearance of the sea buckthorn berry samples (6.6 points). Samples of black currants freeze-dried for 20 h at a shelf temperature of 50 \({}^{\circ}\)C retained their texture exceptionally well, scoring 9.5 points, in contrast to those freeze-dried for 22 h, which received a score of 8.8 points, and those at 18 h, with a score of 7.3 points. Moreover, the taste score for the black currant samples was notably high at 20 h of freeze-drying, achieving a score of 9.2, while those samples freeze-dried for 22 h scored 7.5. The fragrance and appearance of the freeze-dried currants exhibited elevated values after a freeze-drying duration of 20 h. The organoleptic characteristics of freeze-dried sea buckthorn berries, similar to black currant berries, also received high scores after a freeze-drying duration of 20 h.  
Samples that underwent freeze-drying at a shelf temperature of 55 \({}^{\circ}\)C for a duration of 24 h displayed the least favorable organoleptic indicators. The appearance of the black currant samples received a score of 4 points, texture scored 5.7 points, taste was rated at 5.2 points, and aroma reached 4.5 points. The buckthorn samples exhibited a slightly better appearance and flavor compared to the black currant samples, with scores of 5.1 and 5.8 points, respectively. In the sensory evaluation of the black currant and sea buckthorn samples, residual moisture played a significant role, measuring 5.07% and 3.5%, respectively (refer to Table 1).