## 3 Results
### Volatile Compounds in Kiwiberry Juice and Fruit Juices
The apple juice showed also the highest concentration of esters (\(p<0.05\)) with methyl acetate, hexyl acetate, and methyl pentanoate, which was considered to contribute to the positive aroma (fruity, sweet, green, apple). In a mixture of kiwiberry and apple juice, the presence of newly formed compounds such as 2-hexanol, 3-mercapto-4-methyl-2-pentanone and hexyl acetate was observed with the characteristic odors described as fruity, blackcurrant and apple, respectively. The kiwiberry juices with the addition of 50% APJ and 40% APJ showed the highest number of detected volatile compounds. Juice containing 50% APJ showed the highest concentration of esters and alcohols among all tested mixed juices. With the increasing concentration of kiwiberry juice in samples, the higher concentration of ketones and alkanes in the samples was identified. Volatile organic compounds detected in kiwiberry juice, pear juice and their mixtures are listed in Table 3, while the relative content of volatile compounds is presented in Figure 2. The conducted measurements of the pear juice (PEJ) identified the presence of seven volatile constituents that belonged to five compound categories: three esters, two alcohols, one aldehyde, and one alkene. In pear and kiwiberry juice mixes, small differences in the number of detected compounds were observed. In the mixture of kiwiberry and pear juice, the presence of newly formed compounds was observed, belonging to the alcohol compound category, mainly 2-hexanol and (Z)-3-hexen-1-ol, which contributes to fruity, earthy, floral, and fresh odor notes. The compounds 2-propanol, (Z)-1,2,-dicholoroethene, ethyl methacrylate, and hexyl acetate were detected in pear juice as well as in all tested juice mixes, regardless of the used concentration of pear juice. The volatile compounds detected in kiwiberry juice have the strongest effect on the volatile profile in sample 90 PEJ (90% of kiwiberry juice and 10% of pear juice), mainly methyl 2,3-pentanedione with the apple, fruity odour, and 2-propenoate, which were found to serve as negative features to the aroma. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline
**Chem. Family \({}^{*}\)** & **KI MXT-5 \({}^{*}\)** & **KI MXT-1701 \({}^{b}\)** & **Possible Matches** & **Sensory** & **Kbj** & **APJ** & **90 KBJ** & **80 KBJ** & **70 KBJ** & **60 KBJ** & 50 KBJ** \\  & & & **Compounds** & **Descriptors \(**\)** & **–** & **10 APJ** & **20 APJ** & **30 APJ** & **40 APJ** & **50 APJ** \\ \hline Al & 441 & 512 & methanol & alcoholic, strong & x & x & x & x & x & x & x \\ A & 469 & 665 & propenal & almond, cherry & x & x & x & x & x & x & x \\ Al & 496 & 600 & 2-propanol & acetone, etheral & x & x & x & x & x & x & x \\ An & 496 & 513 & pentane & alkane & x & & & & & & \\ E & 588 & 693 & butane-2,3-dione & buttery, & & & & & & & \\ E & 614 & 683 & methyl-2-propenoate & acid & x & & & & & & \\ Ae & 615 & 683 & dichloroethene & sweet & & x & x & x & x & x & x \\ K & 700 & 790 & 2,3-pentanedione & apple, fruity & x & & & & & \\ A & 802 & 895 & hexanal & grassy, green, & & & & & & & \\ Al & 803 & 896 & 2-hexanol & fruity, winey & & & & x & x & x & x \\ E & 815 & 887 & ethyl methacrylate & acid & x & x & x & x & x & x & x \\ Al & 873 & 982 & 1-hexanol & fatty, floral, frailty & & & & & & & \\ Al & 859 & 949 & (Z)-3-hexen-1-ol & floral, earthy, fresh & & & & & & & \\ E & 1011 & 1087 & hexyl acetate & apple, fruity, green & & x & x & x & x & x & x & x \\ \hline \hline \end{tabular}  
* (A)—aldehyde, (Al)—alcohol, (E)—ester, (K)—ketone, (An)—alkane; \({}^{*}\) The sensory descriptions for the listed compounds are taken from ArochemBase; \({}^{*}\) Kovats index for non-polar column; \({}^{b}\) Kovats index for slightly polar column.  
\end{table} 
Table 3: Characterization of the main volatile compounds identified in the headspace of kiwiberry and pear juice and their mixes.