In 2012, the composition of the volatile odorant frac- tion of four aromatic caramels was investigated using gas chroma- gtography coupled either to olfactometry (GC–O) or mass spectrometry (GC–MS) (Paravisini et al., 2012). Seventy-six zones on the chromatograms appeared to be odour-active according to the GC–O study. Unfortunately, only 49 odorant compounds could be identified by GC–MS analysis, due to the complexity of the car- amel volatile fraction which cannot be solved with one-dimen- sional GC analysis. The number of compounds was too high for a single column peak capacity so the separation was highly compro- mised. Moreover, the presence of numerous oxygenated heterocy- clic compounds such as furans and furanones exhibiting similar interactions with the column stationary phase, led to numerous co-elutions, so that the perceived odour could not be related to a single identified compound.