Amina Bouseta

Characteristic aroma profiles of unifloral honeys obtained with a dynamic headspace GC-MS system

The volatile compounds of 84 unifloral honeys (from 14 unifloral sources in 10 countries) were studied with a dynamic headspace gas chromatograph coupled directly to a mass spectrometer system. The average concentrations of the 47 compounds identified are tabulated, together with relevant chromatographic data. Some compounds appeared to be characteristic of the floral source, particularly in lavender (caproaldehyde (hexanal) and heptanal), fir (acetone), eucalyptus (diketones, sulphur compounds, alkanes) and dandelion and rape (three unidentified compounds) honeys. It is concluded that further studies on less volatile compounds are needed in order to further characterize aromas of unifloral honeys and to differentiate honeys derived from floral sources such as chestnut, orange, lime and robinia. Some compounds, such as alcohols, branched aldehydes and furan derivatives, reflected the microbiological purity and processing and storage conditions of the honeys, rather than their floral origins.

Floral quality and discrimination of Lavandula stoechas, Lavandula angustifolia, and Lavandula angustifolia×latifolia honeys

Portuguese lavender honeys are generated from the nectar of Lavandula stoechas, whereas French lavender honeys are exclusively derived from Lavandula angustifolia, Lavandula latifolia, or hybrids of these two species. In the framework of the floral origin authentication of such honeys, volatile compounds from L. stoechas, L. angustifolia, and L. angustifolia×latifolia unifloral honeys were investigated. The aromatic profiles of French and Portuguese lavender honey samples showed major qualitative and quantitative differences, but no volatile compound is characteristic of L. stoechas honeys only. As expected, n-hexanal, n-heptanal, phenylacetaldehyde, and n-hexanol, previously proposed to authenticate French lavender honeys, were found at concentrations far above the published discrimination thresholds. Coumarin, previously proposed to characterize French lavender honeys, emerges here rather as an indicator of the freshness of lavender honey, being mainly released from glycosides during storage. Lastly, L. angustifolia honeys were distinguishable from hybrid-derived samples by their lower phenylacetaldehyde and higher heptanoic acid content.