Chemosensate-Induced Modulation of the Salivary Proteome and Metabolome Alters the Sensory Perception of Salt Taste and Odor-Active Thiols

Oral stimulation with chemosensates was found to trigger changes in the composition of the salivary proteome and metabolome, which translate into a functional modulation of odor and taste perception. Orosensory intervention with 6-gingerol induced a significant increase in the abundance of salivary sulfhydryl oxidase 1, which was found to catalyze the oxidative decline of odor-active 2-furfurylthiol, thus resulting in a decrease in the odorant levels in exhaled breath, as shown by PTR-MS, and a reduction of the perceived sulfury after-smell. Therefore, sulfhydryl oxidase 1 may be considered as a component of a molecular network triggering oral cleansing mechanisms after food ingestion. Moreover, oral stimulation with citric acid, followed by targeted metabolomics, was found to induce a strong increase in salivary concentrations of minerals and, in particular, sodium ions, whereas the other metabolites were rather unaffected. Because of the elevated basal levels of salivary sodium after citric acid stimulation, NaCl test stimuli were perceived as significantly less salty, most likely due to the decreased sensory contrast. This indicates the modulation of the salivary proteome and metabolome to be a major perireceptor event in fine-tuning odor and taste sensitivity.