Human olfactory self-adaptation for structurally-related monoterpenes

Olfactory adaptation influences the temporal perception of flavour. Self-adaptation and cross-adaptation phenomena are sensory effects which may explain discrepancies between the changes in stimulus concentration measured in the breath and changes in perceived sensory intensities during consumption. Olfactory self-adaptation was studied for a group of monoterpenes including (−)-menthol, thymol, (+)-carvone and (−)-carvone. The stimuli were delivered at a weakly perceptible intensity delivered by an automated dynamic olfactometer. The sensory responses were measured by the time-intensity (TI) method and subjects received a constant odour stimulation of 6 min followed by a recovery period without stimulation. Salient differences in self-adaptation were observed between the compounds and between subjects.