## 3 Results and Discussion
### Volatile Organic Compounds
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**IUPAC Name** & **Chemical Class** & **Concise Flavor Description** & **Relative Abundance, \%** \\ \hline  & & Kefir & \\
3-methylbutan-1-ol & Alcohol & Chemical—alcoholic & 35.75 \\ ethanol & Alcohol & Chemical—alcoholic & 16.41 \\ acetic acid & Acid & Dairy—acidic & 14.11 \\ butane-2,3-diol & Alcohol & Dairy—buttery & 9.87 \\ hexanoic acid & Acid & Animal—animal & 8.89 \\ octanoic acid & Acid & Animal—animal & 7.24 \\
2,7-dimethyloctane-4,5-diol & Alcohol & Fruity—sweet & 4.31 \\ decanoic acid & Acid & Animal—animal & 1.59 \\ hexan-1-ol & Alcohol & Chemical—alcoholic & 1.11 \\ octan-2-one & Ketone & Fruity—apple & 0.72 \\ heptan-2-one & Ketone & Fruity—apple & 41.64 \\ nonan-2-one & Ketone & Herbal—ruta & 16.55 \\ hexanoic acid & Acid & Animal—animal & 11.23 \\ ethyl methyl carbonate & Ester & Fruity—sweet & 6.49 \\ octanoic acid & Acid & Animal—animal & 5.57 \\ undecan-2-one & Ketone & Green—fatty/waxy & 3.33 \\ butanoic acid & Acid & Dairy—buttery & 3.17 \\ hexadecan-1-ol & Alcohol & Green—fatty/waxy & 2.95 \\furan-2-ylmethanol & Aromatic alcohol & Roasted—bread & 2.77 \\ octadecanoic acid & Acid & Green—Fatty/Waxy & 2.48 \\ decanoic acid & Acid & Animal—animal & 1.86 \\ nonanoic acid & Acid & Dairy—buttery & 0.91 \\ tetradecan-2-one & Ketone & Unknown & 0.65 \\ hexadecanoic acid & Acid & Green—fatty/waxy & 0.39 \\ Amasi & & \\
3-hydroxybutan-2-one & Ketone/ Alcohol & Dairy—buttery & 64.44 \\ (acetoin) & Acid & Dairy—acidic & 16.90 \\ hexanoic acid & Acid & Animal—animal & 6.76 \\ octanoic acid & Acid & Animal—animal & 3.34 \\ hexadecan-1-ol & Alcohol & Green—fatty/waxy & 2.74 \\ octadecanoic acid & Acid & Green—Fatty/Waxy & 2.45 \\ dec-1-ene & Alkene & Unknown & 1.90 \\ hexadecanoic acid & Acid & Green—fatty/waxy & 0.89 \\ decanoic acid & Acid & Animal—animal & 0.59 \\ pentyl acetate & Ester & Fruity—tropical & 20.20 \\
2-hydroxypropanamide & Amide & Unknown & 20.04 \\ hexadecanoic acid & Acid & Green—fatty/waxy & 15.16 \\ prop-2-enyl hexanoate & Ester & Fruity—tropical & 6.85 \\ ethyl methyl carbonate & Ester & Fruity—sweet & 5.95 \\ pentyl 2-methylpropanoate & Ester & Fruity—sweet & 5.44 \\ tetradecanoic acid & Acid & Green–fatty/waxy & 5.36 \\ (E)-octadec-11-enoic acid & Acid & Unknown & 5.21 \\ pentyl butanoate & Ester & Fruity—tropical & 4.64 \\ ethyl butanoate & Ester & Fruity—tropical & 2.98 \\ ethyl nonanoate & Ester & Fruity—tropical & 2.76 \\ hexanoic acid & Acid & Animal—animal & 2.27 \\ (E)-hex-2-enoic acid & Acid & Animal—animal & 1.77 \\ pentyl 2-methylbutanoate & Ester & Fruity—apple & 1.38 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Volatile organic compounds determined in kefir, ryazhenka, amasi and mhaewu. For each beverage, all determined VOC were classified according to their flavors, and the overall beverages' theoretical (predicted) flavor profiles are presented in Figure 1C. In general, the theoretical flavor profiles can be very different from the actual flavor because of humans' multisensory flavor perception [20]. However, in the case of the studied beverages, the theoretical flavor profiles and actual flavors were in accordance, which allowed for hypothesizing about the contribution of the detected VOC to the overall flavor. It can be proposed that in all products, all of the animal scents can be attributed to the presence of one or more of the following medium-chain fatty acids: hexanoic, octanoic, decanoic and (E)-hex-2-enoic acid. Previously, the presence of these acids was established for several dairy and cereal-based fermented foods and beverages [43; 44; 45]. Moreover, the presence of hexanoic acid was linked with the pungent, rancid, flowery flavor of yogurt by many researchers [19; 46]. While the buttery under-flavor of kefir can be explained by the presence of 2,3-butanediol (10%), in ryazhenka and amasi, this under-flavor is probably produced by the presence of bubritz (or butanoic) acid (3%) and acetoin (64%), respectively.