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 s ampling the volatiles in the mouth during eating have been investigate d. Release of volatiles in the mouth is important in determining the p rofile perceived by the receptors in the nose and thus relates directl y to our perception of aroma when food is eaten. Direct introduction o f volatiles from the mouth and nose into a mass spectrometer did not p rovide information on the volatile profile, as the air introduced grea tly reduced the sensitivity of the machine, and volatiles could not be reliably detected above the background noise. Cryogenic trapping on f used silica capillaries followed by gas chromatography and mass spectr ometry did give profiles which were different for headspace, mouthspac e and nosespace. Problems with loss of volatiles after trapping and th e 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 es timated and found to be menthone (8.32 and 24.3 mg m-3 air) and mentho l (2.59 and 4.3 mg m-3 air), respectively. The concentrations of menth one in both headspace and nosespace were below the reported odour thre shold 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 sensitivit y if the technique is to be applied to other foods.