## 3 Results and Discussion
### Volatile Compounds Identified in Currant Samples Using HS-SPME-GC-FID/MS Method
These C\({}_{6}\) and C\({}_{8}\) compounds are important contributors to the characteristic flavors of many fruits [31], but their profile can be rapidly altered by isomerization or reduction; accordingly, [PERSON] et al. [6] identified the constitutional isomer (E)-3-hexenal. The branched-chain aldehydes 2-methylbutananal and 3-methylbutananal are formed from amino acids, similar to the corresponding alcohols. Benzaldehyde, derived from the shikimate pathway via phenylalanine [31], has been identified as a key component of black currants [14; 17]. Esters are one of the largest groups of volatile constituents in nearly all fruits, contributing to their fruity flavor; they are also important in black currant berries [6; 12; 17]. They can be formed by different reactions: esterification, alcohols, acidosis, or transesterification. These reactions can occur spontaneously or be catalyzed by esterases and lipases [14]. Fatty acids, particularly those with 2, 4, and 6 carbon straight chains, play a major role in ester synthesis, while the source of alcohols and aldehydes for ester synthesis in fruit is not fully understood [31]. Acetic acid and ethanol are most often bound in esters, and [PERSON] [26] also mentions butanoic acid esters as quantitatively important. Four acetates (methyl, ethyl, butyl, and octyl acetate) and five ethyl esters (ethyl butanoate, propanoate, hexanoate, heptanoate, and decanoate) were identified in the samples. Ethyl butanoate and hexanoate were previously recognized as key components of black currants [13; 14; 16]. Based on GC-olfactometry, [PERSON] et al. [16] consider the following esters as the top five most potent compounds in black currant juice aroma: methyl acetate, ethyl propanoate, methyl butanoate, ethyl butanoate, and ethyl hexanoate. Terpenes and their oxygenated derivatives are important volatile compounds in nearly all fruit types, including black currants [8], and their contribution to fruit aroma is well established. Many are stored in plants as glycosides, released by glycosidase activity during maturation. Consequently, they are reported to be indicators of fruit freshness, maturity, botanical and geographical origin, quality, and authenticity [7]. They are derived from saccharides through the metabolic intermediate prevalent acid, which provides the basic structural isoprene unit; many others are formed through transformation of the initial products by oxidation, dehydrogenation, acylation, and other reactions [31]. There has been particular interest in terpen in recent years, mainly because of the biological activity shown by some [11]. Consistent with the literature [7; 9], terpen were numerous in the samples. Eight monoterpenes (\(\beta\)-pinene, sabinene, limonene, \(\delta\)-3-care, \(\alpha\)-terpinene, \(\gamma\)terpinene, terpinolene, and \(\beta\)-phellandrene) and five monoterpenoids (linalol, \(\alpha\)-terpineol, terpinen-4-ol, \(\beta\)-damascenone, and rose oxide) were identified. Terpenoids are known for their strong flavor and represent the characteristic black current flavor, while sesquiterpenes are not considered contributors to black current aroma. The only sesquiterpene found in this study was \(\beta\)-caryophyllene. Limonene, \(\beta\)-phellandrene, linalool, \(\alpha\)-terpineol, \(\beta\)-damascenone, and rose oxide are known as key aroma components of black currants [12,13]. Although most ketones have relatively high flavor thresholds, some, such as the alkan-2-ones, are still important to flavor. They are formed by \(\beta\)-oxidation and decarboxylation of fatty acids, and short-chain (C\({}_{5}\)-C\({}_{11}\)) alkan-2-ones are highly potent flavor molecules found in numerous plants. They are also assumed to be precursors of aroma-active secondary alcohols [31]. Only heptan-2-one was identified in the samples, consistent with [PERSON] et al. [6]. 1-Octen-3-one, along with the corresponding alcohol 1-octen-3-ol, is derived from linoleic acid.