Bitter Taste Perception
Taste is the sensation that certain bodies produce on the taste receptor cells. It is mainly determined by chemical reactions detected by taste (tongue) as well as by olfaction (smell). Eighty percent of what is detected as taste comes from the olfactory sensation.. That is why when a person has an upper repertory tract infection the sensation of any type of taste diminishes.
Taste is detected by the tongue and is produced by the taste buds which are able to distinguish among a large variety of tastes: sweetness, sourness, saltiness, bitterness and, since 2010, umami , identified and catalogued by the scientific community as a new taste. (Umami is a difficult taste to describe; it is associated with Orientals foods, especially with those high in monosodium glutamate.)
Specific taste buds are located on certain parts of the tongue. For example, bitter tastes are perceived especially in the lateral posterior part of the tongue, and sweetness in the anterior part.
According to Oxford Dictionary, bitterness is defined as a "sharpness of taste; lack of sweetness". It is a characteristic taste of bile, quinine and other alkaloids that produces a disagreeable and lasting sensation when it is especially intense. There are some thoughts that suggest that bitterness is perceived as such as a defense mechanism.
Researchers at the Howard Hughes Medical Institute (HHMI) at the University of California, and at the National Institute of Dental and Craniofacial Research (NIDCR) have identified a new gene family which codes the proteins that affect bitter taste perception.
Many medicines, such as aspirin, quinine and some antibiotics are bitter. In foods, bitter is often associated with coffee, chocolate, bitter melon, beer, olives, peels of citrus fruits, eggplant, lemon juice and grapefruit. Occasionally, bitter flavoring is used in cocktails.
Gene or region studied