## 2 Results and Discussion
### _Mentha_ spp. honey solvent-free organic extractives composition isolated by HS-SPME. \begin{table}
\begin{tabular}{l l c c c c c} \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**RI**} & \multicolumn{4}{c}{**Area percentage (\%)**} \\ \cline{4-7}  & & & Min. & Max. & Av. & SD. \\ \hline
1. & 2-Furancarboxaldehyde & \(<900\) & 0.0 & 2.1 & 1.07 & 1.05 \\
2. & 3-Methylbutanoic acid & \(<900\) & 0.0 & 1.4 & 0.57 & 0.74 \\
3. & 2,5-Diethyltetrahydroofuran* & 902 & 0.0 & 2.0 & 0.97 & 1.00 \\
4. & 1-(2-Furanyl)-ethanoneone & 914 & 0.0 & 0.4 & 0.23 & 0.21 \\
5. & Benzaldehyde* & 965 & 0.0 & 0.8 & 0.47 & 0.42 \\
6. & Hexanoic acid* & 974 & 0.0 & 0.3 & 0.13 & 0.15 \\
7. & (Z)-Hex-3-enoic acid & 1013 & 0.0 & 1.0 & 0.43 & 0.51 \\
8. & Benzyl alcohol* & 1037 & 0.7 & 1.0 & 0.83 & 0.15 \\
9. & Phenylacetaldehyde* & 1048 & 0.8 & 1.3 & 1.07 & 0.25 \\
10. & _trans_-Linalool oxide (furan type) & 1076 & 1.8 & 2.8 & 2.37 & 0.51 \\
11. & _cis_-Linalool oxide (furan type) & 1091 & 0.9 & 1.9 & 1.43 & 0.50 \\
12. & Linalool* & 1101 & 1.0 & 3.1 & 1.80 & 1.14 \\
13. & Hotrienol & 1106 & 31.1 & 38.5 & 33.90 & 4.01 \\
14. & 2-Phenylethanol* & 1116 & 1.0 & 2.8 & 1.73 & 0.95 \\
15. & \(\alpha\)-Isophorone & 1124 & 0.0 & 0.6 & 0.27 & 0.31 \\
16. & \(p\)-Mentha-1,5,8-triene** & 1138 & 0.0 & 0.5 & 0.23 & 0.25 \\
17. & Lilac aldehyde (isomer l)** & 1159 & 0.0 & 0.5 & 0.23 & 0.25 \\
18. & Neroloxide & 1162 & 0.9 & 1.9 & 1.37 & 0.50 \\
19. & Epoxylinalool & 1178 & 0.0 & 0.3 & 0.13 & 0.15 \\
20. & Benzoic acid* & 1162 & 0.0 & 0.9 & 0.40 & 0.46 \\
21. & Octanoic acid* & 1174 & 0.0 & 1.6 & 0.63 & 0.85 \\
22. & 3,7-Dimethylocta-1,5-dien-3,7-diol & 1191 & 0.0 & 4.7 & 2.13 & 2.38 \\
23. & 2-Methoxy-4-methylphenol & 1199 & 0.5 & 6.0 & 2.73 & 2.89 \\
24. & 5-Hydroymethylfurfural* & 1230 & 0.0 & 1.0 & 0.53 & 0.50 \\
25. & Phenylacetic acid* & 1269 & 0.0 & 0.8 & 0.47 & 0.42 \\
26. & Nonanoic acid* & 1273 & 0.0 & 2.0 & 0.93 & 1.00 \\
27. & 2-Acetylaniline & 1308 & 0.0 & 2.6 & 1.13 & 1.33 \\
28. & 4-Vinyl-2-methoxyphenol & 1322 & 0.0 & 0.9 & 0.57 & 0.49 \\
29. & 3-Hydroxy-4-phenyl-butan-2-one & 1354 & 1.0 & 2.5 & 1.63 & 0.78 \\
30. & _cis_-Isoeugenol & 1366 & 0.0 & 0.5 & 0.20 & 0.26 \\
31. & Decanoic acid* & 1370 & 0.0 & 0.5 & 0.20 & 0.26 \\
32. & _trans_-\(\beta\)-Damascenone & 1388 & 0.0 & 1.5 & 0.67 & 0.76 \\
33. & Methyl vanillate* & 1527 & 0.0 & 0.9 & 0.47 & 0.45 \\
34. & Methyl syringae* & 1744 & 1.0 & 2.4 & 1.87 & 0.76 \\
35. & Nonadecane* & 1900 & 0.0 & 0.6 & 0.27 & 0.31 \\
36. & Hexadecanoic acid* & 1963 & 1.0 & 2.1 & 1.60 & 0.56 \\ \hline \end{tabular}
\end{table} 
Table 2: _Mentha_ spp. honey solvent-free organic extractives composition isolated by HS-SPME. The major honey headspace compound was hotrienol (31.1%-38.5%) followed by _cis_- and _trans_-linalool oxides (0.9-2.8%), linalool (1.0-3.1%) and neroloxide (0.9-1.9%). A representative chromatogram of solvent-free organic extractives obtained by HS-SPME is presented in Figure 3. Hotrienol is known to be a thermally generated product, but the honey samples were not heated and therefore found hotrienol cannot be considered a thermally generated artifact in this case. These findings support a natural occurrence of hotrienol in non-thermally treated honey. Much lower proportions of hotrienol were found in unripe than in ripe honey, suggesting that hotrienol is probably formed during honey ripening [29] within the hive conditions (temperature, pH, enzymes that can lead to the oxidative degradation of linalool or the cleavage of the glycosidic bonds). Hotrienol can be derived either from 2,6-dimethyl-3,7-ocadiene-2,6-diol (or its glycoconjugate form), from the allylic rearrangement of 3,7-dimethyl-1,7-ocadiene-3,6-diol, or from dehydratation of 8-hydroxylinalool [30]. Hotrienol has been reported as a constituent of different honeys and therefore cannot be considered specific for _Mentha_ spp. honey. However its high percentage in the headspace is a notable characteristic of this particular honey.