Composition of volatile compounds of honey of various floral origin and beebread collected in Lithuania

Honey is collected from various flowering plants and its composition, particularly volatile flavour compounds to some extent depends on the nectar source. Therefore, some volatile constituents may be indicators of honey origin. In this study the volatile profiles of 15 honey samples of different botanical origin and one beebread sample are characterised. Volatiles were collected by means of SPME and analysed by GC/MS. Botanical source of honey samples was established by the melissopalynological method: 11 of analysed samples were unifloral rape honeys, 1 clover, 1 caraway and 2 polyfloral. In total 93 compounds in honey and 32 in beebread were identified. They involve different classes of chemical compounds, including alcohols, ketones, aldehydes, acids, terpenes, hydrocarbons, benzene, and furan derivatives. Benzaldehyde and benzenacetaldehyde were the only compounds found in all 15 honey sample. Dimethyl sulphide, pentanenitrile, benzylnitrile were identified in 14 honeys; isobutane, octanoic and nonanoic acids in 13 samples; furfural, linalool and nonanal in 12 samples; octanal, lilac aldehyde C, hotrienol and decanal in 11 samples and finally 2-methylbutanenitrile in 10 honey volatile fractions. Remarkable variations were observed in the composition of volatiles in honey from different sources. In addition, volatile profiles of honey samples were analysed after 3 months of storage and it was found that the amount of headspace volatiles in the majority of samples decreased.     

Gas chromatographic–mass spectrometric investigation of the chemical composition of beebread

Beebread consumption has a very long tradition; however, its composition and bioactive properties have not been studied thoroughly up to now. This study is expected to expand the knowledge of chemical composition of this bee product as a natural remedy and functional food ingredient. With the help of successive extraction with organic solvents of different polarity, more than 200 compounds were extracted from five samples of beebread and then identified by GC–MS method. The content of some phenol compounds (p-coumaric acid, kaempherol, isorhamnetin) with antioxidant properties has been determined quantitatively. Different content of free aminoacids have been detected in the analyzed samples, which is assumed to be caused by Maillard reaction between aminoacids and carbohydrates.