Flavour index and aroma profiles of fresh and processed honeys

This paper discusses the importance of flavour profiling in detecting indicative parameters for quality control of fresh and heated honey. Flavour compounds of six unifloral honeys (Lavandula stoechas, Castanea sativa, Dorycnium pentaphyllum, Rosmarinus officinalis, Eucalyptus sp and Robinia pseudoacacia) were investigated. The aroma extracts were obtained by a two-step procedure involving (i) preliminary steam distillation under reduced pressure to evaluate the methylpyrazines generated in heated honeys by spectrophotometry (flavour index) and (ii) Likens-Nickerson's simultaneous steam distillation and solvent extraction (SDE) method with added NaCl. A combined total of 64 compounds were detected by gas chromatography/mass spectrometry (GC/MS), 58 of which were identified. Some compounds appeared to be characteristic of the floral source, particularly in Spanish lavender (methylated aliphatic acids and aromatic esters), eucalyptus (2,3-pentanedione, acetoin, 1-hexyl alcohol, 2-acetyl-5-methylfuran, furfuryl propionate, 2-phenylacetaldehyde and nerolidol), chestnut (acetophenone and 2-aminoacetophenone), rosemary and D pentaphyllum (aromatic acids and esters, 2-phenylacetaldehyde, farnesol and thymol) honeys. Robinia honey samples were characterised by very low levels of aromatic compounds. Twenty-six flavour compounds were statistically closely related to the floral origin of the honeys (P less than or equal to 0.05). The flavour index was evaluated progressively in heated honeys, whereas in fresh honeys it showed a minimal value. (C) 2003 Society of Chemical Industry.