# Comparison of Volatile Profiles of Meads and Related Uniflorl Honeys: Traceability Markers
## 2 Results and Discussion
### Headspace Profiles of the Investigated Mead and the Corresponding Honey Samples
Besides losses of VOCs together with CO2 during fermentation [9], an additional amount of volatiles was lost during heating, which resulted in an additional loss of monoterenes in boiled meads. The total percentage of monoterenes in the meads was reduced to zero or nearly zero (buckwheat, honeydew, canola) except for linden honey where it decreased by about 9- or 19-fold for not boiled and boiled mead, respectively. Higher preservation of monoterenes in this variety in contrast to the other ones undoubtedly has an impact on the final, outstanding aroma. The levels of compounds most abundant in linden honey (\(p\)-cymenene--24.27%, \(p\)-cymen-8-ol--13.21% and 4-isopropylcyclohex-1,3-dienecarbaldehyde-4.72%) significantly decreased in the meads. Only small aliquots of \(p\)-cymenene (0.72-0.80%) and \(p\)-cymen-8-ol (2.97%, only in the not boiled mead) were found, except for 4-isopropylcyclohex-1,3-dienecarbaldehyde, which was not detected. This demonstrated that the not boiled meads retain a bit more of the original honey aroma. The total percentage of benzene derivatives reduced by about half in the case of buckwheat and canola meads, and remained stable in the case of linden, but increased threefold for the honeydew mead. Major compounds from this group present in the honeys were: benzaldehyde (13.11%; 27.34%; 0.90%; 6.64% in buckwheat, canola, linden and honeydew respectively), benzyl alcohol (3.02%; 1.61%; 1.65% in buckwheat, canola, honeydew, respectively), phenylacetaldehyde (5.11%; 2.19% in buckwheat and honeydew, respectively), 4-methylphenol in buckwheat (2.98%) and 2-phenylethanol in canola honey (4.13%). Figure 1: The overall percentages of the different volatile organic compound (VOC) structural groups in the analyzed honeys and meads by HS-SPME. BA, BB, BC—buckwheat honey, not boiled and boiled mead, respectively; CA, CB, CC—canola honey, not boiled and boiled mead, respectively; LA, LB, LC—time tree honey, not boiled and boiled mead, respectively; HA, HB, HC—honeydew honey, not boiled and boiled mead, respectively; CCA, CCB, CCC—glucose–fructose syrup, not boiled and boiled mead, respectively. After fermentation, the levels of major benzene derivatives notably decreased, except for 2-phenylethylanol which was generated abundantly in all the honeys and sugar syrup control, reaching from 11.77 to 50.93%. After fermentation, in all honeys, 2-phenethyl  
Figure 2: Comparison of the representative HS-SPME profiles of linden honey (**a**), not boiled mead (**b**) and boiled mead (**c**). acetate appeared (up to 4.25%) as well as other minor compounds. 2-Phenylathanol is the known fermentation product deriving from L-phenylalanine [10; 11] and 2-phenethyl acetate characterizes fermentation by _Saccharomyces cerevisiae_ yeast [12]. The fluctuations of their abundance in boiled and not boiled meads were very small. The fermentation process and the mode of preparation had strong impact on changes in amounts of different groups of aliphatic compounds in the headspace profiles. The levels of aliphatic hydrocarbons (0.49, 2.98, 42.61% for canola, honeydew, control, respectively) and aldehydes (13.82, 1.58, 13.46% for buckwheat, canola, honeydew, respectively) decreased to zero in the meads. The percentages of aliphatic alcohols, acids and esters significantly increased in the meads in comparison with floral honey types. The increase of aliphatic alcohols and esters was much higher for the not boiled meads than for the boiled ones. In the case of esters, the difference was 2-fold. The increase of aliphatic acids percentage was much higher in the boiled meads, from 2- to nearly 5-fold higher. The difference between percentage of aliphatic acids in honey and the not boiled mead depended on the honey type, i.e., for buckwheat and honeydew honey it was small and for canola and linden the difference was big. The meads were characterized by high total percentage of aliphatic esters synthetized during fermentation [13] reaching from 7.38% to 57.11% and 2-3 times more than in the corresponding honey.