# Comparison of Volatile Profiles of Meads and Related Uniflorl Honeys: Traceability Markers
## 2 Results and Discussion
### DHLLE Extract Profiles of the Investigated Mead and the Corresponding Honey Samples  
The GC-FID/MS analyses of the DHLLE extracts allowed us to identify 53 compounds from different chemical functional groups (Table 2). In contrast to the HS-SPME extracts, monoterpens were relevant in the DHLLE extracts only for linden honey and meads. The major compound groups dominating the extracts were aliphatic compounds and benzene derivatives. Additionally, nitrogen compounds and furan derivatives were found in the extracts. The comparison between profiles of the meads and the corresponding unifloral honeys showed relevant differences (Figure 3). Within the group of aliphatic compounds, hydrocarbons dominated in the honeys and oxygenated compounds (mainly alcohols, acids and esters) were more abundant in the meads. There were observable trends in the abundance of aliphatic compounds, depending on mead preparation method. The not boiled meads contained more aliphatic hydrocarbons and esters while the boiled meads contained more aliphatic alcohols and acids. The most abundant hydrocarbon in honey was tricosane (up to 25.35%). The not boiled meads contained up to 5.20% of this compound and high percentage of esters, mainly ethyl hexadecanoate (up to 24.98%) and ethyl octadecanoate (up to 37.17%). The boiled meads contained lower percentages of these esters (up to 22.65% and 16.67%, respectively) but also contained higher amounts of acids and alcohols, mainly octadecanoic acid (up to 19.07%), hexadecanoic acid (up to 4.92%) and alcohols, mainly (\(Z\))-octadec-9-en-1-ol (up to 3.81%) and octadecan-1-ol (up to 4.54%). A similar trend was observed for benzene derivatives. The highest total percentage of these compounds was present in the boiled meads. In the not boiled meads it was higher, equal or lower than in the honey, depending on the botanical source. Substantial differences occurred after fermentation: 2-phenylethanol appeared in the meads, more abundant in the boiled (up to 17.11%) and less in the not boiled ones (up to 8.61%). In buckwheat mead, \(p\)-hydroxybenzoic acid level decreased in the not boiled (3.29%) and increased in the bailed (16.11%) meads in contrast to the honey (5.65%). On the other hand, the levels of 2,3-dihydroneofuran in the same honey type were 7.64%, 0.94% and 4.33% for the honey, the not boiled and the boiled mead, respectively. For the honeybee, the biggest differences were observed in homovanillic acid (0.36%, 0.35%, 4.89%) and coniferyl alcohol (0.47%, 1.68%, 3.46%) percentages observed in the honey, the not boiled and the boiled meads, respectively. A significant increase in the case of boiled meads was observed and could be explained by the hydrolysis of non-volatile derivatives of these compounds during cooking, for example. Nitrogen compounds were usually most abundant in the boiled meads. Tryptophan appeared only in the meads and was more abundant in the boiled (up to 4.81%) than in the not boiled ones (up to 1.68%). Buckwheat honey and meads also contained 1-isoquinolencarbonitrile (1.37%, 0.49% 0.93%), 1\(H\)-indole-3-acetonitrile (3.58%, 0.02%, 1.38%) and 1\(H\)-indole-3-carboxaldehyde (3.30%, 0.78%, 5.00%). The latter was previously found in buckwheat honey [8] however detailed research is necessary to verify if these compounds may be considered chemical markers of buckwheat in the honey and mead. Monoterpenes were almost not detected except for linden honey and meads. The latter retained some part of 4-isopropenylcyclohex-1,3-diene-1-carboxylic acid (22.83%, 15.05%, 23.64%) and 4-(1-hydroxy-2-propanyl)cyclohex-1,3-diene-1-carboxylic acid (29.27%, 18.35%, 22.37%) in the honey and the not boiled or the boiled mead, respectively. Interestingly, the not boiled meads retained less of them. DHLE extracts allowed us also to detect some furan compounds: small amounts of 2,4-dihydroxy-2,5-dimethyl-3(2H)-furan-3-one in all the honey and mead samples and \(\gamma\)-valerolactone in the buckwheat honey and meads.