## 3 Results and Discussion
### Evolution of VOC Profiles During Successive Kefir Grain Passages
\begin{table}
\begin{tabular}{c l c c} \hline
**No.** & **Compound** & **Odor Descriptor** & **ODT** \\ \hline \multicolumn{3}{c}{Organic acids} \\ \hline
2 & Octanoic acid & Sweat, cheese [27] & 0.50 [28] \\ \hline \multicolumn{3}{c}{Alcohols} \\ \hline
3 & 1-Dodecanol & Raw carrot [29] & 0.016 [30] \\ \hline
6 & 1-Hexadecanol & Floral, wavy [31] & 0.75 [32] \\ \hline
7 & 1-Hexanol & Resin, flower, green [31, 33] & 0.0056 [34] \\ \hline
8 & 1-Octanol & Soap, fruity [29, 35] & 0.1258 [36] \\ \hline
9 & 1-Pentanol & Pungent, fermented, bready, yeasts, oil, wine, solvent [37] & 0.12 [38] \\ \hline
10 & 1-Undecanol & Fruity [35] & 0.70 [39] \\ \hline
15 & 2-Heptanol & Mushroom-like [36], green [40] & 0.05823 [34] \\ \hline
16 & 2-Hexanol & Fatty, fruity [36] & 1.5082 [36] \\ \hline
17 & 2-Methyl-1-propanol & Mat [41] & 0.55 [34] \\ \hline
18 & 2-Nonanol & Green, fruity [29, 4, 2] & 0.07 [39] \\ \hline
19 & 2-Phenylethanol & Honey [36], floral, rose-like [43] & 0.5642 [34] \\ \hline
20 & 2-Undecanol & Fruity [42] & 0.041 [42] \\ \hline
21 & 3-Methyl-1-pentanol & Wine, green [36] & 0.0075 [34] \\ \hline
26 & Furfuryl alcohol & Sugar burnt [44] & 4.50 [34] \\ \hline \multicolumn{3}{c}{Aldehydes} \\ \hline
27 & (E)-2-Hexenal & Floral, grass, green apple-like, bitter almond-like [41, 45] & 0.11 [34] \\ \hline
28 & (E)-2-Nonneal & Fatty, green [41] & 0.00029 [34] \\ \hline
32 & 2-Methylbutanal & Nutty [36] & 0.001 [34] \\ \hline
33 & 4-Hydroxy-3-methoxybenzaldehyde & Sweet [41], creamy vanilla-like [46] & 0.053 [41] \\ \hline
34 & 5-Hydroymethylfurfurfural & Sweet, caramel [47] & 1.00 [34] \\ \hline
35 & Benzaldehyde & Bitter almond [29, 36] & 0.75089 [36] \\ \hline \end{tabular}
\end{table} 
Table 1: Odor descriptors and odor detection thresholds (ODTs in mg/L) of volatile organic compounds detected in nonreferenced isovifruit juice (RICG) and various, klovi kef-like beverages, as reported in the literature. \begin{table}
\begin{tabular}{c l c c} \hline
**No.** & **Compound** & **Odor Descriptor** & **ODT** \\ \hline
36 & Furfural & Wood, almond [36] & 14.10 [28] \\ \hline  & Ketones & \\ \hline
37 & 2,6-Dimethyl-4-heptanone & Fruify, sweet [48] & 0.11 [49] \\ \hline
38 & 2-Heptanone & Banana, fruity, floral and musty, fresh cream flavor [29] & 0.005 [50] \\ \hline
39 & 4-Methyl-2-hexanone & Fruify [51] & 0.002455 [34] \\ \hline  & Esters & \\ \hline
43 & 2-Methylbutyl acetate & Banana, fruity [52] & 0.16 [52] \\ \hline
44 & 2-Phenylethyl acetate & Flowery [53], fruity, cooked apple, marmalade [54] & 0.24959 [34] \\ \hline
52 & Ethyl 3-phenylpropanoate & Fruify, floral [55] & 0.014 [46] \\ \hline
53 & Ethyl butanoate & Fruity, apple-like, banana-like, sweet, fragrant [36, 56] & 0.0009 [36] \\ \hline
54 & Ethyl decanoate & Fruity [56] & 0.2 [28] \\ \hline
55 & Ethyl dodecanoate & Fruity, floral [56] & 5.9 [34] \\ \hline
56 & Ethyl hexadecanoate & Fruity, creamy, wavy [57] & 2.00 [58] \\ \hline
57 & Ethyl hexanoate & Fruity, pineapple-like [59] & 0.014 [28] \\ \hline
58 & Ethyl octanoate & Sweet [55], fruity, floral [43] & 0.005 [43] \\ \hline
59 & Heyl acetate & Banana [29], green apple, sweet [60] & 0.67 [52] \\ \hline
60 & Methyl benzoate & Fruity, sweet [53] & 0.0005 [53] \\ \hline
64 & Pentyl acetate & Fruity [56] & 0.043 [56] \\ \hline  & & Furans & \\ \hline
65 & 2,5-Dimethyl-4-hydroxy-3(2H)-furanone & Caramel-like [61] & 0.01 [62] \\ \hline \end{tabular}
\end{table} 
Table 1: _Cont._