## 2 Results and Discussion
### Qualitative Analysis of VOCs in Kiwiberry Cultivars
In contrast, \(E\),\(E\)-2,6-dimethyl-1,3,5,7-octateraene, butanoic acid, and _cis_-carvool were lost after pressurization. The major volatile compounds of \(A\). _arguta_ were mainly esters, alcohols, and aldehydes, with ethyl butanoate, ethyl hexanoate, (\(E\))-2-hexenal, and hexanal as the main contributors to its aroma [12]. These authors also reported that 1-penten-3-one, pentanal, 1-octen-3-ol, linalool, terpinen-4-ol, and \(\alpha\)-terpineol substantially contribute to the kiwiberry aroma of the cv Ananasnaya. Moreover, flavor compounds also accumulate in plant tissue material as nonvolatile glycoconjugates, and they have been considered an important potential source of flavor compounds, which can be released from the sugar moiety during either maturation or processing [3]. According to the findings presented in the work of [PERSON] et al. [12], hexanal and 1-octen-3-ol appear in both the bound and free volatile extracts of ripe \(A\). _arguta_. It is well known that HHP induces the disruption of plant cell walls through mechanical damage during compression (pressure build up) and decompression phenomena, which in turn can facilitate both the extractability and release of some compounds from the complexes formed with other plant tissue constituents [2]. This phenomenon was likely responsible for the appearance of new volatiles in the group of samples subjected to the HHP treatment. VOCs identified in the cvs Geneva and Weiki can be grouped into different chemical classes: alcohols, aldehydes, carboxylic acids, esters, ketones, and terpenoids (Figures 1 and 2). The predominant group identified in the native Geneva (Figure 1) are terpenoids (39% of the total number of identified VOCs), followed by aldehydes (22%), esters (17%), alcohols (11%), and ketones (11%). Evidently, the contribution of terpenoids to the VOC profile of Geneva is reduced after HHP treatment. The largest decrease in this contribution (from 39% to 19%) was observed after sample exposure to 650 MPa (irrespective of the processing time). In contrast, a distinct increase was found in the contribution of the alcohols (from 11 to 27%) and aldehydes (from 22 to 31%) to the VOC profile after sample processing at 650 MPa for 5 min and 15 min, respectively. The results presented were consistent with recently published data [9], which showed an increasing trend towards the contribution of alcohols to the VOC profile of kiwifruit juice after processing at 500 MPa for 10 min. Contrary to our results, however, these authors observed a slight reduction in the aldehyde contribution after pressurization, which in turn resulted in a deterioration in the freshness of kiwifruit juice, as aldehydes are mainly desirable compounds, with a grassy aroma. Similarly, the dominant volatile group found in the untreated Weiki were terpenids (Figure 2), and in this case, pressurization decreased their contribution to the VOC profile. The most pronounced drop (from 52% to 41%) was observed after sample exposure to 450 MPa/15 min, 550 MPa/5 min, and 650 MPa/15 min, respectively. On the other hand, the pressurization of Weiki induced an increase in the contribution of aldehydes and alcohols. The most distinct increased in aldehyde (from 7% to 18%) and alcohol (from 11% to 19%) contributions was found after exposure of Weiki to a pressure of 450 MPa for 5 and 15 min, respectively. As mentioned above, the contribution of esters showed an irregular change with pressurization. Exposure of Weiki to higher pressure levels distinctly increased the contribution of ketones, particularly the treatment at 650 MPa/15 min, after which an increase from 4% to 10% was observed. As mentioned above, the profile of the VOCs, with an emphasis on hydrocarbon terpenes, alcohols, esters, or aldehydes, can be altered by HHP processing. Moreover, pressurization can enhance and/or retard various enzymatic and chemical reactions, and this, in turn, can directly affect the content of particular volatiles, as well as their contribution to the kiwiberry aroma [13]. According to [PERSON] et al.