HUMAN TASTE TEST: Taste is the ability to respond to dissolved molecules and ions called tastants, which humans detect via taste receptor cells, clustered into taste buds. The tongue has about 10,000 taste buds. When these detect food particles, they send signals to the brain carrying information about their "taste." Each taste bud contains 50-100 taste cells, representing the five taste sensations: salty, sour, sweet, bitter and umami (the response to acidic salts like MSG, often used as a flavor enhancer in Asian dishes, processed meats, and processed cheeses, often labeled "savory"). Recent research indicates the existence of a sixth taste, one for calcium.
Each taste cell has receptors that bind to specific molecules and ions responsible for the various taste sensations, which connect to a sensory neuron leading back to the brain. So taste -- like all sensations -- resides in the brain. That's the reason different people like different things. Although a single cell may have several types of receptors, one may be more active than the others, so certain tastes will be preferred by that individual. Also, no single taste cell contains receptors for both bitter and sweet tastants.
THE NOSE KNOWS: Our sense of taste is partially enhanced by smell, which is why food may taste bland when we have a cold that blocks the nasal passages. Nerve receptor cells within the nose detect odors carried into the organ by air, and transmit signals to the brain through the olfactory nerve.
This report has also been produced thanks to a generous grant from The Camille and Henry Dreyfus Foundation, Inc.