## 3 Results and Discussion
### Effect of Cultivar on Volatile Composition of Currants  
As confirmed by many authors, fruit volatile profiles can be influenced by various pre-harvest (e.g., cultural practices) and post-harvest (e.g., processing, storage) factors [31]. Considering that the tested currants were cultivated under the same conditions, harvested at full ripeness, and analyzed fresh, the cultivar is the main factor influencing their variability. However, very few publications compare currant cultivars. We can mention studies by [PERSON] et al. [6], [PERSON] et al. [7], [PERSON] et al. [10], and [PERSON] et al. [17], who compared several black currant cultivars (none of which overlapped with ours) and confirmed the significant effect of cultivar on aroma compound composition. Only [PERSON] and [PERSON] [11] analyzed differences in the terpene composition of 'Ben Hope', a well-established cultivar grown in the UK, describing the terpene fraction as largely associated with the distinctive black currant aroma. In the case of red currants, [PERSON] [26] analyzed Jonkheer [PERSON]', 'Rovada', and 'Tatran'--cultivars also included in our study. Many studies do not mention cultivars at all, meaning that most of the cultivars we analyzed have not yet been the subject of published research. The variance in the content of compounds identified in red/white/black currants is provided in Supplementary Material Table S2. Consistent with previous studies, alcohols, aldehydes, and esters were the major classes of volatile compounds and quantitatively predominated in nearly all varieties. In contrast, [PERSON] et al. [6] also found terpen to be predominant in several black currant cultivars. Despite the similar number of compounds identified, significant differences in the proportions of most volatiles were observed between cultivars within both the red/white and black currant groups (see Table S2). This is consistent with the findings of other authors [7; 9], who also found differences between cultivars in the quantitative rather than the qualitative composition of compounds. A comparison of volatile compounds in single cultivars within red/white/black currant variants is provided in Supplementary Material Table S3. Comparing individual compound classes, alcohols ranged from 11.5% to 48.5% in red/white currants and were less abundant in black currants (9.2-37.4%). The following alcohols were present in all cultivars (concentration range in parentheses): ethanol (87.6-1090.2 ug/kg), butan-1-ol (0-53.2 ug/kg), pentan-1-ol (0-14.4 ug/kg), hexan-1-ol (4.7-45.8 ug/kg), butan-2-ol (3.4-98.2 ug/kg), and 1-octen-3-ol (0-38.5 ug/kg), with ethanol quantitatively predominating. The differences between cultivars were significant for all detected alcohols except (E)-3-hexen-1-ol (\(p\) = 0.33). This compound was found in minimal concentrations (0-6.2 ug/kg) and only in eight red and black cultivars (see Table S3). Consistent with [PERSON] [26], it was not present in white currants. (E)- and (Z)-3-hexen-1-ol, in contrast to [PERSON] [26], where these compounds were found to be predominant in black currants, were present only in small quantities (<6.6 ug/kg) in our samples. Aldehydes ranged from 15.1% to 30.2% in red/white cultivars and from 21.1% to 37.4% in black cultivars, with ethanol predominating in nearly all cultivars. Ethanol (19.6-455.7 ug/kg), hexanal (18.9-85.6 ug/kg), 2-methylbutanal (13.7-231.1 ug/kg), 3-methylbutanal (37.3-266.6 ug/kg), octanal (3.3-136.6 ug/kg), and nonanal (0-17.9 ug/kg) were present in all cultivars. [PERSON] et al. [17] found that hexanal, nonanal, and (E)-2-octenal to significantly contribute to the overall aroma of black currants. These compounds were also predominantly present in our black cultivars. Significant differences were found between cultivars for all detected aldehydes except decanal (\(p\) = 0.09). In contrast to [PERSON] et al. [17], who considered this compound a significant contributor to black currant aroma, it was found in minimal concentrations (0-6.4 ug/kg) in 10 red and black cultivars.