Flavour from the molecules to the behaviour

Oral enzymatic detoxification system: Insights obtained from proteome analysis to understand its potential impact on aroma metabolization

The oral cavity is an entry path into the body, enabling the intake of nutrients but also leading to the ingestion of harmful substances. Thus, saliva and oral tissues contain enzyme systems that enable the early neutralization of xenobiotics as soon as they enter the body. Based on recently published oral proteomic data from several research groups, this review identifies and compiles the primary detoxification enzymes (also known as xenobiotic-metabolizing enzymes) present in saliva and the oral epithelium. The functions and the metabolic activity of these enzymes are presented. Then, the activity of these enzymes in saliva, which is an extracellular fluid, is discussed with regard to the…

Impact of aldehyde dehydrogenases and aldo-keto reductases on human olfactory peri-receptor events

International audience

The Relationship Between Salivary Redox, Diet, and Food Flavor Perception.

The mouth is the gateway for entrance of food and microorganisms into the organism. The oral cavity is bathed by saliva, which is thus the first fluid that food and microorganisms will face after their entrance. As a result, saliva plays different functions, including lubrication, predigestion, protection, detoxification, and even transport of taste compounds to chemoreceptors located in the taste buds. To ensure its function of protection, saliva contains reactive harmful compounds such as reactive oxygen species that are controlled and neutralized by the antioxidant activity of saliva. Several antioxidant molecules control the production of molecules such as reactive oxygen compounds, neu…

Activités oxydo-réductrices dans la salive : modulation par l’alimentation et importance pour la perception sensorielle des aliments

Resume La salive est un fluide complexe contenant des electrolytes, des molecules organiques, des microorganismes, des debris alimentaires et cellulaires, mais aussi des proteines de differentes natures qui lui permettent d’assurer de nombreuses fonctions. La salive a entre autres un role dans le controle et la modulation des dommages resultant de mecanismes oxydants en bouche. Cet article introduit les principaux composes salivaires impliques dans le stress oxydant et ceux impliques dans la neutralisation de ces especes oxydantes, le maintien du potentiel redox et la reparation des dommages issus de l’oxydation des biomolecules en bouche. Il propose un etat des lieux des connaissances sur …

Impact of Oral Microbiota on Flavor Perception: From Food Processing to In-Mouth Metabolization.

International audience; Flavor perception during food intake is one of the main drivers of food acceptability and consumption. Recent studies have pointed to the oral microbiota as an important factor modulating flavor perception. This review introduces general characteristics of the oral microbiota, factors potentially influencing its composition, as well as known relationships between oral microbiota and chemosensory perception. We also review diverse evidenced mechanisms enabling the modulation of chemosensory perception by the microbiota. They include modulation of the chemosensory receptors activation by microbial metabolites but also modification of receptors expression. Specific enzy…

Diversity of Omega Glutathione Transferases in mushroom-forming fungi revealed by phylogenetic, transcriptomic, biochemical and structural approaches

International audience; The Omega class of glutathione transferases (GSTs) forms a distinct class within the cytosolic GST superfamily because most of them possess a catalytic cysteine residue. The human GST Omega 1 isoform was first characterized twenty years ago, but it took years of work to clarify the roles of the human isoforms. Concerning the kingdom of fungi, little is known about the cellular functions of Omega glutathione transferases (GSTOs), although they are widely represented in some of these organisms. In this study, we re-assess the phylogeny and the classification of GSTOs based on 240 genomes of mushroom-forming fungi (Agaricomycetes). We observe that the number of GSTOs is…

In-mouth metabolism and production of flavor sulfur compounds by oral microbiota enzymes

Flavor perception is the main factor in the acceptance of food. Cysteine derivatives are aroma precursors present in a number of plant-based foods (vegetables, fruits, as well as beverages such as wine). They have low odorant properties, but become odorant when metabolized into aroma sulfur compounds in the oral cavity. These sulfur compounds are sometimes associated with food aversion. Therefore, it is desirable to improve our knowledge of the entailed enzymatic mechanisms and design strategies aiming at controlling their release in-mouth. The involved enzymes are presumably carbon-sulfur lyases (C-S lyases) from the oral microbiota, but evidences are scarce. Recently, we showed that saliv…

Molecules of the flavor

Perception of weeds and their ecosystem (dis)services by farmers, advisors, experimenters and researchers in France

Development of a new in vitro model of oral mucosa to investigate a new hypothesis on the molecular origin of astringency

Astringency is described as an oral tactile perception occurring during the consumption of tannin-rich foods. This sensation, mediated by the trigeminal nerves, participates negatively to the flavor of foods leading to the rejection of food with high astringency by the consumer. The exact molecular mechanism of its origin and the nature of the sensory receptors activated are still under debate. Up to recently, the main hypotheses involved changes in the lubrication properties of the oral cavity triggering the activation of mechanoreceptors. Recently, we have put a new hypothesis involving the mucin MUC1 forward as an explanation of the origin of astringency. MUC1 is a transmembrane mucin wi…

Is there a role for salivary detoxification enzymes in taste perception?

International audience

Role of oxidoreductase enzymes in olfactory perireceptor events

Role of human metabolizing enzymes in food perception

Flavor 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 sa…

Metabolism of flavor sulfur precursors by the oral microbiota

Mucin MUC1: a key protein in oral physiology and the molecular mechanisms of sensory perception of astringency

Interactions between odorants and glutathione transferases in the human olfactory cleft

AbstractXenobiotic metabolizing enzymes and other proteins, including odorant-binding proteins located in the nasal epithelium and mucus, participate in a series of processes modulating the concentration of odorants in the environment of olfactory receptors (ORs) and finely impact odor perception. These enzymes and transporters are thought to participate in odorant degradation or transport. Odorant biotransformation results in 1) changes in the odorant quantity up to their clearance and the termination of signaling and 2) the formation of new odorant stimuli (metabolites). Enzymes, such as cytochrome P450 and glutathione transferases (GSTs), have been proposed to participate in odorant clea…