CONTRIBUTION OF AIR-AND BONE-CONDUCTION TO THE CREATION OF SOUNDS PERCEIVED DURING SENSORY EVALUATION OF FOODS

The noises perceived during sensory evaluation of foods are transmitted to the innerear by both air and bone conduction. The contribution of the two conductions was studied for six foods "croquant" (crunchy), "craquant" (crackle) and "croustillant" (crispy), by six panelists. It was studied by reconstituting the attenuation of the air and bone conduction records needed to imitate sound actually heard during sensory evaluation of foods. The eating technique (bite or chew) modified the contribution of air- and bone-conduction to auditory sensation. Differences were shown between foods, but they could not clearly distinguish between the kinds of food. Modifying the attenuation of the air- and bone-conduction records was not enough. The bone-conduction records had to be attenuated over a frequency range around 160 Hz, which is the resonance frequency of the mandible. The air-conduction records had to be attenuated at a frequency range around 160 Hz and amplified at a frequency range around 3,500 Hz in order to match the action of the middle-ear muscles which behave differently when sounds were generated inside or outside the mouth.