## 3 Results and Discussion
### Evolution of VOC Profiles During Successive Kefir Grain Passages

Table 3: Odor activity values (OAVs) of the volatile organic compounds detected in the different kiwi keft-like beverages obtained from the second keft grain-passage (24–48 h). \begin{table}
\begin{tabular}{l l c c c c c c c c c} \hline \hline
**No.** & **Compound** & **Dev1-48 h** & **Dev2-48 h** & **Dev3-48 h** & **Dev4-48 h** & **Dev5-48 h** & **Dev6-48 h** & **Dev7-48 h** & **Dev4-48 h** & **Dev9-48 h** \\ \hline  & \multicolumn{8}{c}{Ketones} \\ \hline
23 & 2.6-Dimethyl-4-heptanone & 5.82 & 4.18 & 3.73 & 9.55 & 12.00 & 10.73 & 4.27 & 6.09 & 7.55 \\ \hline
24 & 2-Heptanone & – & – & – & 42.00 & – & – & – & – & – \\ \hline
25 & 4-Methyl-2-hexanone & – & – & – & – & – & – & – & – \\ \hline  & \multicolumn{8}{c}{Esters} \\ \hline
26 & 2-Methylbutyl acetate & 1.38 & – & 0.94 & – & – & – & – & – & – \\ \hline
27 & 2-Phenylethyl acetate & 0.12 & – & – & – & 0.68 & 1.20 & 0.20 & – & – \\ \hline
28 & Ethly 3-phenyl/propanoate & – & – & – & – & – & – & – & – \\ \hline
29 & Ethly butanoate & – & – & – & – & – & – & – & – \\ \hline
30 & Ethly decanoate & – & – & 1.35 & – & – & 6.10 & 1.15 & – & 0.90 \\ \hline
31 & Ethly dodecanoate & – & – & 0.02 & – & – & 0.10 & 0.02 & – & 0.03 \\ \hline
32 & Ethly hexadecanoate & – & – & – & – & – & – & – & – \\ \hline
33 & Ethly hexadecanoate & 73.57 & – & 29.29 & 9.29 & – & 42.14 & 8.57 & – & – \\ \hline
34 & Ethly octanoate & 24.00 & 22.00 & 56.00 & 98.00 & – & 86.00 & 92.00 & – & 52.00 \\ \hline
35 & Heayl acetate & – & – & – & – & – & – & – & – & – \\ \hline
36 & Methyl benzoate & 365.38 & 134.62 & 288.46 & – & – & – & – & 211.54 & – \\ \hline
37 & Pentiy acetate & 1.40 & – & – & – & – & 8.37 & – & – & – \\ \hline  & \multicolumn{8}{c}{Furans} \\ \hline
38 & 2,5-Dimethyl-4-hydroxy-3(2H)-furanone & 10.00 & 16.00 & 58.00 & 27.00 & – & 49.00 & 31.00 & 21.00 & 28.00 \\ \hline  & \multicolumn{8}{c}{**Number of VOCs with OAVs \(\geq\) 1.0**} & 12 & 8 & 10 & 11 & 4 & 14 & 8 & 8 & 10 \\ \hline \hline \end{tabular}
\end{table} 
Table 3. Cont. \begin{table}
\begin{tabular}{l l c c c c c c c c c c} \hline \hline
**No.** & **Compound** & **Bev1-72 h** & **Bev2-72 h** & **Bev3-72 h** & **Bev4-72 h** & **Bev5-72 h** & **Bev6-72 h** & **Bev7-72 h** & **Bev8-72 h** & **Bev9-72 h** \\ \hline  & & & & & & Organic acids & & & & & \\ \hline
1 & Octanoic acid & – & – & – & – & – & – & – & 0.38 & – & – \\ \hline  & & & & & & Alcohols & & & & & \\ \hline
2 & 1-Dodecanol & – & 9.38 & 20.00 & 29.38 & – & – & – & – & 8.75 \\ \hline
3 & 1-Hexadecanol & – & 0.76 & 1.63 & 1.08 & – & – & – & 0.44 & 0.53 \\ \hline
4 & 1-Hexanol & – & – & – & 66.07 & – & – & – & – & 46.43 \\ \hline
5 & 1-Octanol & – & – & – & – & – & – & – & – & 3.42 \\ \hline
6 & 1-Pentanol & 63.00 & 40.58 & 25.58 & 16.67 & 39.25 & 62.67 & 41.25 & 21.75 & 47.75 \\ \hline
7 & 1-Undecanol & – & 0.37 & 0.39 & 0.70 & – & 1.09 & 0.30 & 0.79 & 0.39 \\ \hline
8 & 2-Heptanol & – & – & – & – & – & – & – & 1.99 \\ \hline
9 & 2-Hexanol & – & – & – & – & – & – & – & – \\ \hline
10 & 2-Methyl-1-propanol & 1.20 & 1.11 & 0.89 & 0.65 & 2.15 & 1.69 & 0.51 & 0.84 & 1.36 \\ \hline
11 & 2-Nonanol & – & – & – & – & – & – & – & – & – \\ \hline
12 & 2-Phenylethanol & 2.80 & 2.98 & 1.58 & 1.21 & 2.43 & 4.20 & 3.35 & 1.38 & 2.23 \\ \hline
13 & 2-Undecanol & – & – & 3.17 & 8.05 & – & 11.46 & 2.93 & 16.10 & 6.59 \\ \hline
14 & 3-Methyl-1-pentanol & – & – & – & – & – & 13.33 & – & – \\ \hline
15 & Furfuryl alcohol & 0.10 & 0.03 & 0.04 & 0.06 & – & 0.05 & 0.06 & 0.22 & – \\ \hline \hline \multicolumn{11}{c}{Aldehydes} \\ \hline
16 & (E)-2-Hexenal & – & – & - & 1.73 & – & – & – & – & 1.45 \\ \hline
17 & (E)-2-Nonneal & – & – & 338.98 & 406.78 & – & 542.37 & 610.17 & 847.46 & 440.68 \\ \hline
18 & 2-Methylbutanal & – & – & – & – & – & – & 320.00 & – \\ \hline
19 & 4-Hydroxy-3-methoxybenzaldehyde & 10.38 & 4.34 & 5.85 & 7.36 & – & 4.91 & 6.60 & – & 7.55 \\ \hline
20 & 5-Hydrosymethylfurfural & – & – & – & – & – & – & 0.78 & – \\ \hline \hline \end{tabular}
\end{table}