Characterization of the volatile profile of thistle honey using headspace solid-phase microextraction and gas chromatography–mass spectrometry

In this study, a headspace solid-phase microextraction method was developed for the characterization of the volatile fraction of thistle honey and compared with a dynamic headspace extraction method. A DVB/CAR/PDMS fibre was used. The effects of extraction time, equilibration time and salt addition on extraction yield were evaluated. The volatile fraction of seven Italian thistle honey samples was extracted under the optimized conditions and analyzed by gas chromatography–mass spectrometry. Characterization of the volatile profile was performed in terms of nature and relative amount of the extracted compounds. A total of 40 compounds, belonging to different chemical classes, were identified. The relative amounts of 16 compounds found in all the analyzed thistle honeys, i.e. nonanal, furfural, decanal, 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran, benzaldehyde, α-linalool, lilac aldehyde (isomer IV), hotrienol, phenylacetaldehyde, 4-oxoisophorone, benzyl alcohol, 2-phenylethanol, a not identified compound, octanoic acid, nonanoic acid and methyl anthranilate, were calculated and submitted to statistical analysis, in order to define for each compound a typical range. On the basis of the obtained data, a characteristic set of values was defined for thistle honey volatile fingerprint. The developed model proved to be effective in recognizing the botanical origin of thistle honey.