Role of human metabolizing enzymes in food perception

International audienceFlavor is the main factor determining food acceptability. Flavor corresponds to the combination of the signals from the gustatory system, the olfactory system and the trigeminal system. Interactions between proteins and flavor molecules in oral/nasal cavities are proposed to modulate flavor perception through a series of events knowns as perireceptor events. Among these proteins involved in this modulation are found enzymes mainly known for their role in the detoxification process. These enzymes are able to recognize a large panel of molecules. We proposed to explore the role of these enzymes in food perception. We demonstrated that enzymatic activities present in the oral epithelium and saliva, and in the olfactory mucus led to odorant molecules metabolization. Enzymes metabolize odorant molecules in order to eliminate them, consequently participating to the termination of the flavor signal. Additionally, the odorant metabolites have their own sensory properties and can also be perceived, contributing to modulate the flavor perception. Using a combination of technics including mass spectroscopy, immunohistochemistry, enzymology and radiocristallography, we identify and characterize different enzymes related to this flavor perception in the oral cavity (at the level of aroma molecules and tastants). This research contributes to clarify the understanding of the metabolization of odorant and tastant molecules in the oral cavity and their consequences on flavor perception