Glycosidically bound flavour compounds in Quercus petraea Liebl. wood

To isolate the bound aroma compounds (BVC fraction) from Quercus petraea Liebl. heartwood, two different methods, XAD-2 adsorption and liquid-liquid extractions, were applied. Only the extraction procedures permitted, for the first time, the isolation and separation of this fraction. The free volatiles were first extracted with pentane:dicholoromethane in a ratio 2:1 (v/v) and the bound compounds with ethyl acetate. The bound aroma was determined directly by trifluoroacetamide (TFA) derivatives analysis, and indirectly by acid hydrolysis release of aglycons. Analyses were achieved, in each case, by GC-MS (EI and CI): several bound components were isolated and different aglycons identified, e.g. whisky lactones (cis + trans), eugenol, megastigmatrienones, vanillin and syringaidehyde. Each of these can be considered as a source of potential aroma; they have a specific odour in their free form. Copyright (c) 2005 John Wiley & Sons, Ltd.