Selection of a representative extraction method for the analysis of odourant volatile composition of French cider by GC–MS–O and GC × GC–TOF-MS

The experimental conditions of a representative odour extraction method were determined after testing eight SPME, dynamic headspace and purge-and-trap procedures. Headspace SPME with a Car/PDMS fibre was evidenced to be the most suitable method to obtain representative extract of cider odour. This method was applied to extract the volatile compounds of two French ciders and gas chromatography–mass spectrometry–olfactometry (GC–MS–O) was used to analyse the odourant profile and the aroma-active compounds of these ciders. Thirty-six odourant zones were perceived in one cider and 24 in the other. Comprehensive two-dimensional gas chromatography combined with time-of-flight mass spectrometry was used to identify odour-active compounds which were undetermined after the first chromatographic separation. Ethyl 2-methylbutanoate, 2-phenylethanol, ethyl butanoate, ethyl 2-methylpropanoate, ethyl hexanoate, oct-1-en-3-one, 2-phenylethyl acetate, ethyl dodecanoate, 3-methyl-1-butanol and 2-methylbutanoic acid were among the most potent odourants in both ciders, as well as oct-1-en-3-one, which could be identified only by comprehensive GC. Thanks to the association of the two methods, 80% of the aroma-active compounds were identified, some of them being present at trace levels in ciders.