MEASUREMENT OF VOLATILE RELEASE IN THE MOUTH

Using extra strong mints as a simple food system, which contains high levels of volatiles and a simple aroma profile, different methods of sampling the volatiles in the mouth during eating have been investigated. Release of volatiles in the mouth is important in determining the profile perceived by the receptors in the nose and thus relates directly to our perception of aroma when food is eaten. Direct introduction of volatiles from the mouth and nose into a mass spectrometer did not provide information on the volatile profile, as the air introduced greatly reduced the sensitivity of the machine, and volatiles could not be reliably detected above the background noise. Cryogenic trapping on fused silica capillaries followed by gas chromatography and mass spectrometry did give profiles which were different for headspace, mouthspace and nosespace. Problems with loss of volatiles after trapping and the presence of water on the traps limited the usefulness of this method. Trapping on Tenax traps overcame some of these problems. and similar profiles to those obtained with cryogenic trapping were obtained. The amounts of two major volatiles in the headspace and nosespace were estimated and found to be menthone (8.32 and 24.3 mg m-3 air) and menthol (2.59 and 4.3 mg m-3 air), respectively. The concentrations of menthone in both headspace and nosespace were below the reported odour threshold value, but menthol was present in concentrations above the odour threshold. The method shows that volatile profiles during eating can be measured, but further development is required to improve sensitivity if the technique is to be applied to other foods.