umami

Meaning: Umami is the savory, "meaty" taste quality. It is produced chiefly by glutamate (as in MSG, aged cheese, tomatoes, and meat broths) and is generally thought to signal protein-rich food. Gustation is a chemical sense. Tastants dissolve in saliva and bind receptors on taste receptor cells in taste buds, which sit in papillae on the tongue. Umami and sweet are detected by G protein-coupled receptors, while salty and sour depend more on ion movement through channels. Taste signals travel through cranial nerves to the brainstem, then the thalamus, then the gustatory cortex.

On the MCAT: Expect umami in a list of the five basic tastes in a sensation and perception passage or question. You may be asked to name the taste produced by glutamate, or to tell taste (a receptor-level sensation) from flavor, which combines taste with smell and texture. A common setup is a stuffy nose making food seem bland, because the olfactory contribution to flavor is reduced while taste is largely intact.

Common confusion: Students often recall the "tongue map," with each taste confined to its own zone. In fact, all basic tastes can be detected across the tongue, though sensitivity varies somewhat by region. Also, MSG contains sodium, but umami is a response to glutamate, not to saltiness.