tastes

Tastes, or gustation, is the sense by which the tongue and other parts of the oral cavity detect soluble chemical substances. In humans, five basic tastes are generally recognized: sweet, sour, salty, bitter, and umami. Some researchers note proposed additional tastes, such as fat or metallic flavors, but these are not universally accepted as basic tastes.

Taste receptors reside in taste buds, small clusters of receptor cells located on the tongue's taste papillae—fungiform on the tip and sides, circumvallate at the back, and foliate along the edges—as well as in other areas of the mouth and throat. Receptor cells respond to tastants and transmit signals via the sensory nerves VII (facial), IX (glossopharyngeal), and X (vagus) to the brain, where gustatory perception is combined with smell and texture to form flavor.

Each basic taste reflects a different chemical property: sweet from sugars and some amino acids; sour from acids (hydrogen ions); salty from salts, principally sodium ions; bitter from a diverse set of compounds; and umami from glutamates and certain nucleotides. Many tastants act through receptor proteins on the cell surface, initiating neural impulses that are interpreted as specific tastes.

Individual taste sensitivity varies due to genetic differences in taste receptors (for example TAS1R and TAS2R gene families) and other factors such as age, health, and medications. A well-known variation involves the ability to taste the bitter compound PTC or PROP; some people are "supertasters" with heightened taste perception.

In everyday life, taste influences food choice, nutrition, and safety, and interacts with smell, aroma, and texture to create flavor. Scientific study of taste spans neuroscience, physiology, and food science and informs nutrition, product design, and clinical practice related to eating and swallowing.