Taste - AbsoluteAstronomy.com

Taste is one of the traditional five sense

Sense

Senses are physiological capacities of organisms that provide inputs for perception. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience, cognitive psychology , and philosophy of perception...

s. It refers to the ability to detect the flavor

Flavor

Flavor or flavour is the sensory impression of a food or other substance, and is determined mainly by the chemical senses of taste and smell. The "trigeminal senses", which detect chemical irritants in the mouth and throat as well as temperature and texture, are also very important to the overall...

of substances such as food

Food

Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals...

, certain minerals, and poison

Poison

In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....

s, etc.

Humans receive tastes through sensory organs called taste bud

Taste bud

Taste buds contain the receptors for taste. They are located around the small structures on the upper surface of the tongue, soft palate, upper esophagus and epiglottis, which are called papillae. These structures are involved in detecting the five elements of taste perception: salty, sour,...

s, or gustatory calyculi, concentrated on the upper surface of the tongue

Tongue

The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...

.

The sensation of taste can be categorized into five basic tastes: sweet, bitterness, sour, salty

Salty

Salty may refer to the following:* salt* Saltiness, one of the five basic tastes* salt * salience* LondonerFictional characters:* Salty the Seal, character in Disney's Pluto cartoons...

, and umami

Umami

Umami , popularly referred to as savoriness, is one of the five basic tastes together with sweet, sour, bitter, and salty.-Etymology:Umami is a loanword from the Japanese meaning "pleasant savory taste". This particular writing was chosen by Professor Kikunae Ikeda from umai "delicious" and mi ...

. The recognition and awareness of umami is a relatively recent development in Western cuisine. MSG

Monosodium glutamate

Monosodium glutamate, also known as sodium glutamate or MSG, is the sodium salt of glutamic acid, one of the most abundant naturally occurring non-essential amino acids....

produces a strong umami taste.

As taste senses both harmful and beneficial things, all basic tastes are classified as either appetitive or aversive, depending upon the effect the things they sense have on our bodies. Sweetness helps to identify energy-rich foods, while bitterness serves as a warning sign of poisons.

The basic tastes contribute only partially to the sensation and flavor

Flavor

of food in the mouth — other factors include smell

Odor

An odor or odour is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors...

, detected by the olfactory epithelium

Olfactory epithelium

The olfactory epithelium is a specialized epithelial tissue inside the nasal cavity that is involved in smell. In humans, it measures about 1 square centimetre and lies on the roof of the nasal cavity about 7 cm above and behind the nostrils...

of the nose; texture, detected through a variety of mechanoreceptor

Mechanoreceptor

A mechanoreceptor is a sensory receptor that responds to mechanical pressure or distortion. There are four main types in the glabrous skin of humans: Pacinian corpuscles, Meissner's corpuscles, Merkel's discs, and Ruffini corpuscles...

s, muscle nerves, etc.; temperature, detected by thermoreceptor

Thermoreceptor

A thermoreceptor is a sensory receptor, or more accurately the receptive portion of a sensory neuron, that codes absolute and relative changes in temperature, primarily within the innocuous range...

s; and spiciness, or piquance

Piquance

Piquance is a sensation associated with the sense of taste. In various Asian countries it has traditionally been considered a basic taste.-Etymology:...

, also called chemesthesis

Chemesthesis

Chemesthesis is defined as the chemical sensibility of the skin and mucus membranes. Chemesthetic sensations arise when chemical compounds activate receptors associated with other senses that mediate pain, touch, and thermal perception. These chemical-induced reactions do not fit into the...

History

In The West

The Western World

"The Western World" is the sixth track from Pennywise's ninth studio album Reason to Believe. It was the album's first single, which also reached number 22 on the Modern Rock Tracks chart, marking the highest initial charting single in Pennywise's career...

, Aristotle

Aristotle

Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...

, who postulated c.

Circa

Circa , usually abbreviated c. or ca. , means "approximately" in the English language, usually referring to a date...

350 BCE that the two most basic tastes were sweet and bitter, was one of the first to develop a list of basic tastes.

Ayurveda

Ayurveda

Ayurveda or ayurvedic medicine is a system of traditional medicine native to India and a form of alternative medicine. In Sanskrit, words , meaning "longevity", and , meaning "knowledge" or "science". The earliest literature on Indian medical practice appeared during the Vedic period in India,...

, an ancient India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

n healing science, has its own tradition of basic tastes, including: astringent

Astringent

An astringent substance is a chemical compound that tends to shrink or constrict body tissues, usually locally after topical medicinal application. The word "astringent" derives from Latin adstringere, meaning "to bind fast"...

, bitter, pungent, salty, sour, and sweet.

Recent discoveries

The receptors

Receptor (biochemistry)

In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

for the basic tastes of bitter, sweet and umami have been identified. They are G protein-coupled receptor

G protein-coupled receptor

G protein-coupled receptors , also known as seven-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein-linked receptors , comprise a large protein family of transmembrane receptors that sense molecules outside the cell and activate inside signal...

s.. The cells that detect sour have been identified as a subpopulation that express the protein PKD2L1. The responses are mediated by an influx of protons into the cells but the receptor for sour is still unknown . The receptor for amiloride-sensitive attractive salty taste in mice has been shown to be a sodium channel.
There is some evidence for a sixth taste that senses fatty substances.

Taste-map myth

Despite a common misconception that different sections of the tongue specialized in different tastes, all taste sensations come from all regions of the tongue.

Basic tastes

For a long period, it was commonly accepted that there is a finite and small number of "basic tastes" of which all seemingly complex tastes are ultimately composed. Just as with primary color

Primary color

Primary colors are sets of colors that can be combined to make a useful range of colors. For human applications, three primary colors are usually used, since human color vision is trichromatic....

s, the "basic" quality of those sensations derives chiefly from the nature of human perception, in this case the different sorts of tastes the human tongue

Tongue

can identify. Until the twenty-first century, the number of "basic" tastes was considered to be four (bitterness, saltiness, sourness, and sweetness). More recently, a fifth taste, "savory

Umami

" or "umami", has been proposed by a large number of authorities associated with this field. In Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

n countries within the sphere of mainly Chinese

Chinese cuisine

Chinese cuisine is any of several styles originating in the regions of China, some of which have become highly popular in other parts of the world – from Asia to the Americas, Australia, Western Europe and Southern Africa...

, Indian

Indian cuisine

Indian cuisine consists of thousands of regional cuisines which date back thousands of years. The dishes of India are characterised by the extensive use of various Indian spices, herbs, vegetables and fruit. Indian cuisine is also known for the widespread practice of vegetarianism in Indian society...

and Japanese

Japanese cuisine

Japanese cuisine has developed over the centuries as a result of many political and social changes throughout Japan. The cuisine eventually changed with the advent of the Medieval age which ushered in a shedding of elitism with the age of shogun rule...

cultural influence, Piquance

Piquance

Piquance is a sensation associated with the sense of taste. In various Asian countries it has traditionally been considered a basic taste.-Etymology:...

has traditionally been considered a sixth basic taste.

Bitterness

Bitterness is the most sensitive of the tastes, and is perceived by many to be unpleasant, sharp, or disagreeable. Common bitter foods and beverages include coffee

Coffee

Coffee is a brewed beverage with a dark,init brooo acidic flavor prepared from the roasted seeds of the coffee plant, colloquially called coffee beans. The beans are found in coffee cherries, which grow on trees cultivated in over 70 countries, primarily in equatorial Latin America, Southeast Asia,...

, unsweetened cocoa

Hot chocolate

Hot chocolate is a heated beverage typically consisting of shaved chocolate, melted chocolate or cocoa powder, heated milk or water, and sugar...

, South American mate

Mate (beverage)

Mate , also known as chimarrão or cimarrón, is a traditional South American infused drink, particularly in Argentina, Uruguay, Paraguay, southern states of Brazil, south of Chile, the Bolivian Chaco, and to some extent, Syria and Lebanon...

, marmalade

Marmalade

Marmalade is a fruit preserve made from the juice and peel of citrus fruits, boiled with sugar and water. The benchmark citrus fruit for marmalade production in Britain is the "Seville orange" from Spain, Citrus aurantium var...

, bitter melon

Bitter melon

Momordica charantia, called bitter melon or bitter gourd in English, is a tropical and subtropical vine of the family Cucurbitaceae, widely grown in Asia, Africa, and the Caribbean for its edible fruit, which is among the most bitter of all fruits...

, beer

Beer

Beer is the world's most widely consumed andprobably oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. It is produced by the brewing and fermentation of sugars, mainly derived from malted cereal grains, most commonly malted barley and malted wheat...

, bitters

Bitters

A bitters is an alcoholic beverage that is flavored with herbal essences and has a bitter or bittersweet flavor. There are numerous brands of bitters that were formerly marketed as patent medicines but are now considered to be digestifs, rather than medicines...

, olives, citrus peel

Peel (fruit)

Peel, also known as rind or skin, is the outer protective layer of a fruit or vegetable which could be peeled off. The rind is usually the botanical exocarp, but the term exocarp does also include the hard cases of nuts, which are not named peels since they are not peeled off by hand or peeler, but...

, many plants in the Brassicaceae

Brassicaceae

Brassicaceae, a medium sized and economically important family of flowering plants , are informally known as the mustards, mustard flowers, the crucifers or the cabbage family....

family, dandelion greens, wild chicory

Chicory

Common chicory, Cichorium intybus, is a somewhat woody, perennial herbaceous plant usually with bright blue flowers, rarely white or pink. Various varieties are cultivated for salad leaves, chicons , or for roots , which are baked, ground, and used as a coffee substitute and additive. It is also...

, escarole and lemons. Quinine

Quinine

Quinine is a natural white crystalline alkaloid having antipyretic , antimalarial, analgesic , anti-inflammatory properties and a bitter taste. It is a stereoisomer of quinidine which, unlike quinine, is an anti-arrhythmic...

is also known for its bitter taste and is found in tonic water

Tonic water

Tonic water is a carbonated soft drink in which quinine is dissolved. Originally used as a prophylactic against malaria, tonic water usually now has a significantly lower quinine content and is consumed for its distinctively bitter taste...

.

Bitterness is of interest to those who study evolution

Evolution

Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

, as well as various health researchers since a large number of natural bitter compounds are known to be toxic. The ability to detect bitter-tasting, toxic compounds at low thresholds is considered to provide an important protective function. Plant leaves often contain toxic compounds, yet even amongst leaf-eating primates, there is a tendency to prefer immature leaves, which tend to be higher in protein and lower in fiber and poisons than mature leaves. Amongst humans, various food processing

Food processing

Food processing is the set of methods and techniques used to transform raw ingredients into food or to transform food into other forms for consumption by humans or animals either in the home or by the food processing industry...

techniques are used worldwide to detoxify otherwise inedible foods and make them palatable.

The threshold for stimulation of bitter taste by quinine averages a concentration of 0.000008 M . The taste thresholds of other bitter substances are rated relative to quinine, which is thus given a reference index of 1. For example, Brucine

Brucine

Brucine is a bitter alkaloid closely related to strychnine. It occurs in several plant species, the most well known being the Strychnos nux-vomica tree, found in South-East Asia.While brucine is related to strychnine, it is not as poisonous...

has an index of 11, is thus perceived as intensely more bitter than quinine, and is detected at a much lower solution threshold. The most bitter substance known is the synthetic chemical denatonium

Denatonium

Denatonium, usually available as denatonium benzoate and as denatonium saccharide, is the bitterest chemical compound known; with bitterness thresholds of 0.05 ppm for the benzoate and 0.01 ppm for the saccharide.It was discovered in 1958 during research on local anesthetics by Macfarlan...

, which has an index of 1,000. It is used as an aversive agent

Aversive agent

Aversive agents are unpleasantly flavored substances added to poisonous household goods in order to discourage children from consuming the poisonous household products. Aversive agents are not intended to be harmful, only unpleasant...

that is added to toxic substances to prevent accidental ingestion. This was discovered in 1958 during research on lignocaine, a local anesthetic, by Macfarlan Smith of Edinburgh

Edinburgh

Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...

, Scotland

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

.

Research has shown that TAS2Rs (taste receptors, type 2, also known as T2Rs) such as TAS2R38

TAS2R38

TAS2R38 is a bitter taste receptor which facilitates the tasting of phenylthiocarbamide and propylthiouracil , although it does not explain supertasting.. Carriers of the PAV allele experience more bitterness from vegetables and consume vegetables less frequently and in lower amounts ....

coupled to the G protein

G protein

G proteins are a family of proteins involved in transmitting chemical signals outside the cell, and causing changes inside the cell. They communicate signals from many hormones, neurotransmitters, and other signaling factors. G protein-coupled receptors are transmembrane receptors...

gustducin

Gustducin

Gustducin is a G protein associated with basic taste and the gustatory system. Due to its relatively recent discovery and isolation, not all is known about its nature and its associated pathways. It is known that it plays a large role in the transduction of bitter, sweet and umami stimuli and...

are responsible for the human ability to taste bitter substances. They are identified not only by their ability to taste for certain "bitter" ligands, but also by the morphology of the receptor itself (surface bound, monomeric). Recently it is speculated that the selective constraints on the TAS2R family have been weakened due to the relatively high rate of mutation and pseudogenization. Researchers use two synthetic substances, phenylthiocarbamide

Phenylthiocarbamide

Phenylthiocarbamide, also known as PTC, or phenylthiourea,is an organosulfur thiourea containing a phenyl ring.It has the unusual property that it either tastes very bitter or is virtually tasteless, depending on the genetic makeup of the taster...

(PTC) and 6-n-propylthiouracil

Propylthiouracil

Propylthiouracil or 6-n-Propylthiouracil is a thioamide drug used to treat hyperthyroidism by decreasing the amount of thyroid hormone produced by the thyroid gland...

(PROP) to study the genetics

Genetics

Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....

of bitter perception. These two substances taste bitter to some people, but are virtually tasteless to others. Among the tasters, some are so-called "supertaster

Supertaster

A supertaster is a person who experiences the sense of taste with far greater intensity than average. Women are more likely to be supertasters, as are individuals of Asian and African descent. The cause of this heightened response is currently unknown, although it is thought to be, at least in...

s" to whom PTC and PROP are extremely bitter. The variation in sensitivity is determined by two common alleles at the TAS2R38 locus. This genetic variation in the ability to taste a substance has been a source of great interest to those who study genetics.

Saltiness

Saltiness is a taste produced primarily by the presence of sodium ions. Other ions of the alkali metals group also taste salty, but the further from sodium the less salty the sensation is. The size of lithium

Lithium

Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly...

and potassium

Potassium

Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

ions most closely resemble those of sodium and thus the saltiness is most similar. In contrast rubidium

Rubidium

Rubidium is a chemical element with the symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group. Its atomic mass is 85.4678. Elemental rubidium is highly reactive, with properties similar to those of other elements in group 1, such as very rapid...

and cesium ions are far larger so their salty taste differs accordingly. The saltiness of substances is rated relative to sodium chloride

Sodium chloride

Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...

(NaCl), which has an index of 1. Potassium, as potassium chloride

Potassium chloride

The chemical compound potassium chloride is a metal halide salt composed of potassium and chlorine. In its pure state, it is odorless and has a white or colorless vitreous crystal appearance, with a crystal structure that cleaves easily in three directions. Potassium chloride crystals are...

- KCl, is the principal ingredient in salt substitute

Salt substitute

Salt substitutes are low-sodium table salt alternatives marketed to circumvent the risk of high blood pressure and cardiovascular disease associated with a high intake of sodium chloride while maintaining a similar taste...

s, and has a saltiness index of 0.6.

Other monovalent

Valence (chemistry)

In chemistry, valence, also known as valency or valence number, is a measure of the number of bonds formed by an atom of a given element. "Valence" can be defined as the number of valence bonds...

cations, e.g. ammonium

Ammonium

The ammonium cation is a positively charged polyatomic cation with the chemical formula NH. It is formed by the protonation of ammonia...

, NH₄⁺, and divalent

Divalent

In chemistry, a divalent ion or molecule has a valence of two and thus can form two bonds with other ions or molecules. An older term for divalent is bivalent....

cations of the alkali earth metal group of the periodic table

Periodic table

The periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus...

, e.g. calcium, Ca²⁺, ions generally elicit a bitter rather than a salty taste even though they, too, can pass directly through ion channels in the tongue, generating an action potential

Action potential

In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and...

Sourness

Sourness is the taste that detects acid

Acid

An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

ity. The sourness of substances is rated relative to dilute hydrochloric acid

Hydrochloric acid

Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

, which has a sourness index of 1. By comparison, tartaric acid

Tartaric acid

Tartaric acid is a white crystalline diprotic organic acid. It occurs naturally in many plants, particularly grapes, bananas, and tamarinds; is commonly combined with baking soda to function as a leavening agent in recipes, and is one of the main acids found in wine. It is added to other foods to...

has a sourness index of 0.7, citric acid

Citric acid

Citric acid is a weak organic acid. It is a natural preservative/conservative and is also used to add an acidic, or sour, taste to foods and soft drinks...

an index of 0.46, and carbonic acid

Carbonic acid

Carbonic acid is the inorganic compound with the formula H2CO3 . It is also a name sometimes given to solutions of carbon dioxide in water, because such solutions contain small amounts of H2CO3. Carbonic acid forms two kinds of salts, the carbonates and the bicarbonates...

an index of 0.06.

Sour taste is detected by a small subset of cells that are distributed across all taste buds in the tongue. Sour taste cells can be identified by expression of the protein PKD2L1 , although surprisingly this gene is not required for sour responses. The mechanism by which animals detect sour is still not completely understood. There is evidence that the protons that are abundant in sour substances can directly enter the sour taste cells. This transfer of positive charge into the cell can itself trigger an electrical response. It has also been proposed that weak acids such as acetic acid, which are not fully dissociated at physiological pH values, can penetrate taste cells and thereby elicit an electrical response. According to this mechanism, intracellular hydrogen ions inhibit potassium channels, which normally function to hyperpolarize the cell. By a combination of direct intake of hydrogen ions (which itself depolarizes the cell) and the inhibition of the hyperpolarizing channel, sourness causes the taste cell to fire action potentials and release neurotransmitter.

The most common food group that contains naturally sour foods is fruit

Fruit

In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

, with examples such as lemon

Lemon

The lemon is both a small evergreen tree native to Asia, and the tree's ellipsoidal yellow fruit. The fruit is used for culinary and non-culinary purposes throughout the world – primarily for its juice, though the pulp and rind are also used, mainly in cooking and baking...

, grape

Grape

A grape is a non-climacteric fruit, specifically a berry, that grows on the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten raw or they can be used for making jam, juice, jelly, vinegar, wine, grape seed extracts, raisins, molasses and grape seed oil. Grapes are also...

, orange

Orange (fruit)

An orange—specifically, the sweet orange—is the citrus Citrus × sinensis and its fruit. It is the most commonly grown tree fruit in the world....

, and sometimes melon

Melon

thumb|200px|Various types of melonsThis list of melons includes members of the plant family Cucurbitaceae with edible, fleshy fruit e.g. gourds or cucurbits. The word "melon" can refer to either the plant or specifically to the fruit...

. Wine

Wine

Wine is an alcoholic beverage, made of fermented fruit juice, usually from grapes. The natural chemical balance of grapes lets them ferment without the addition of sugars, acids, enzymes, or other nutrients. Grape wine is produced by fermenting crushed grapes using various types of yeast. Yeast...

also usually has a sour tinge to its flavor. If not kept correctly, milk

Milk

Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...

can spoil and contain a sour taste.
Sour candy is especially popular in North America including Cry Babies

Cry Baby (gum)

Cry Baby is a brand of extra sour bubble gum manufactured by Tootsie Roll Industries, Inc.Their claim to fame is their incredibly sour coating, which disappears shortly after the gum is chewed...

, Warheads, Lemon drop

Lemon drop

A lemon drop is a sugary, lemon-flavored candy that is typically colored yellow and often shaped like a miniature lemon. They can be sweet or have a more sour flavor....

s, Shock tarts and Sour Skittles

Skittles (confectionery)

Skittles is a brand of fruit-flavoured sweets, currently produced and marketed by the Wm. Wrigley Jr. Company, a division of Mars, Inc. They have hard sugar shells which carry the letter S. The inside is mainly sugar, corn syrup, and hydrogenated palm kernel oil along with fruit juice, citric acid,...

and Starburst. Many of these candies contain citric acid

Citric acid

Citric acid is a weak organic acid. It is a natural preservative/conservative and is also used to add an acidic, or sour, taste to foods and soft drinks...

Sweetness

Sweetness, usually regarded as a pleasurable sensation, is produced by the presence of sugar

Sugar

Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...

s, some proteins and a few other substances. Sweetness is often connected to aldehyde

Aldehyde

An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....

s and ketone

Ketone

In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

s, which contain a carbonyl group. Sweetness is detected by a variety of G protein coupled receptors coupled to the G protein

G protein

gustducin

Gustducin

found on the taste bud

Taste bud

s. At least two different variants of the "sweetness receptors" need to be activated for the brain to register sweetness. The compounds which the brain senses as sweet are thus compounds that can bind with varying bond strength to two different sweetness receptors. These receptors are T1R2+3 (heterodimer) and T1R3 (homodimer), which are shown to be accountable for all sweet sensing in humans and animals. Taste detection thresholds for sweet substances are rated relative to sucrose

Sucrose

Sucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula...

, which has an index of 1. The average human detection threshold for sucrose is 10 millimoles per litre. For lactose

Lactose

Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...

it is 30 millimoles per litre, with a sweetness index of 0.3, and 5-Nitro-2-propoxyaniline

5-Nitro-2-propoxyaniline

5-Nitro-2-propoxyaniline, also known as P-4000 and Ultrasüss, is one of the strongest sweet-tasting substances known, about 4,000 times the intensity of sucrose. It is an orange solid that is only slightly soluble in water. It is stable in boiling water and dilute acids...

0.002 millimoles per litre.

Umami

Umami is an appetitive

Appetite

The appetite is the desire to eat food, felt as hunger. Appetite exists in all higher life-forms, and serves to regulate adequate energy intake to maintain metabolic needs. It is regulated by a close interplay between the digestive tract, adipose tissue and the brain. Decreased desire to eat is...

taste and is described as a savory or meat

Meat

Meat is animal flesh that is used as food. Most often, this means the skeletal muscle and associated fat and other tissues, but it may also describe other edible tissues such as organs and offal...

y taste. It can be tasted in cheese

Cheese

Cheese is a generic term for a diverse group of milk-based food products. Cheese is produced throughout the world in wide-ranging flavors, textures, and forms....

and soy sauce

Soy sauce

Soy sauce is a condiment produced by fermenting soybeans with Aspergillus oryzae or Aspergillus sojae molds, along with water and salt...

, and while also found in many other fermented and aged foods, this taste is also present in tomatoes, grains, and beans. Monosodium glutamate

Monosodium glutamate

Monosodium glutamate, also known as sodium glutamate or MSG, is the sodium salt of glutamic acid, one of the most abundant naturally occurring non-essential amino acids....

(MSG), developed as a food additive in 1908 by Kikunae Ikeda

Kikunae Ikeda

was a Japanese chemist and Tokyo Imperial University professor in Chemistry who, in 1908, uncovered the chemical root behind a taste he named umami. He discovered the common component that produced the flavor of meat, seaweed and tomatoes was glutamate, which produces the sensation of umami.He also...

, produces a strong umami taste. A loanword

Loanword

A loanword is a word borrowed from a donor language and incorporated into a recipient language. By contrast, a calque or loan translation is a related concept where the meaning or idiom is borrowed rather than the lexical item itself. The word loanword is itself a calque of the German Lehnwort,...

from Japanese

Japanese language

is a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is a member of the Japonic language family, which has a number of proposed relationships with other languages, none of which has gained wide acceptance among historical linguists .Japanese is an...

meaning "good flavor" or "good taste", is considered fundamental to many Eastern

Eastern world

__FORCETOC__The term Eastern world refers very broadly to the various cultures or social structures and philosophical systems of Eastern Asia or geographically the Eastern Culture...

cuisines and was first described in 1908, although it was only recently recognized in the West

Western world

The Western world, also known as the West and the Occident , is a term referring to the countries of Western Europe , the countries of the Americas, as well all countries of Northern and Central Europe, Australia and New Zealand...

as a basic taste.

Some umami taste buds respond specifically to glutamate in the same way that "sweet" ones respond to sugar. Glutamate binds to a variant of G protein coupled glutamate receptors.

Measuring relative tastes

Measuring the degree by which a substance presents one basic taste can be done in a subjective way by comparing its taste to a reference substance.

Quinine

Quinine

, a bitter medicinal found in tonic water

Tonic water

, can be used to subjectively rate the bitterness of a substance. Units of dilute quinine hydrochloride (1 g in 2000 mL of water) can be used to measure the threshold bitterness concentration, the level at which the presence of a dilute bitter substance can be detected by a human taster, of other compounds. More formal chemical analysis, while possible, is difficult.

Relative saltiness can be rated by comparison to a dilute salt solution.

The sourness of a substance can be rated by comparing it to very dilute hydrochloric acid

Hydrochloric acid

Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

(HCl).

Sweetness is subjectively measured by comparing the threshold values, or level at which the presence of a dilute substance can be detected by a human taster, of different sweet substances. Substances are usually measured relative to sucrose

Sucrose

, which is usually given an arbitrary index of 1 or 100. Fructose

Fructose

Fructose, or fruit sugar, is a simple monosaccharide found in many plants. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed directly into the bloodstream during digestion. Fructose was discovered by French chemist Augustin-Pierre Dubrunfaut in 1847...

is about 1.4 times sweeter than sucrose; glucose

Glucose

Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

, a sugar found in honey and vegetables, is about three-quarters as sweet; and lactose

Lactose

, a milk sugar, is one-half as sweet.

Functional structure

Bitterness:
Research has shown that TAS2Rs (taste receptors, type 2, also known as T2Rs) such as TAS2R38

TAS2R38

are responsible for the human ability to taste bitter substances. They are identified not only by their ability to taste certain bitter ligands, but also by the morphology of the receptor itself (surface bound, monomeric).

Saltiness:
Saltiness is a taste produced best by the presence of cations

Ion

An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...

(such as , or ) and, like sour, it is tasted using ion channel

Ion channel

Ion channels are pore-forming proteins that help establish and control the small voltage gradient across the plasma membrane of cells by allowing the flow of ions down their electrochemical gradient. They are present in the membranes that surround all biological cells...

s.

Other ions of the alkali metals group also taste salty, but the less sodium-like the ion is, the less salty the sensation. As the size of lithium

Lithium

and potassium

Potassium

ions is close to that of sodium, they taste similar to salt. In contrast, the larger rubidium

Rubidium

and cesium ions do not taste as salty.

Other monovalent

Valence (chemistry)

In chemistry, valence, also known as valency or valence number, is a measure of the number of bonds formed by an atom of a given element. "Valence" can be defined as the number of valence bonds...

cations, e.g., ammonium

Ammonium

The ammonium cation is a positively charged polyatomic cation with the chemical formula NH. It is formed by the protonation of ammonia...

, , and divalent

Divalent

In chemistry, a divalent ion or molecule has a valence of two and thus can form two bonds with other ions or molecules. An older term for divalent is bivalent....

cations of the alkali earth metal group of the periodic table

Periodic table

, e.g., calcium, , ions, in general, elicit a bitter rather than a salty taste even though they, too, can pass directly through ion channel

Ion channel

s in the tongue.

Sourness:
Sourness is acid

Acid

ity, and, like salt, it is a taste sensed using ion channel

Ion channel

s. Hydrogen ion channels detect the concentration of hydronium ions that are formed from acids and water. In addition, the taste receptor PKD2L1 has been found to be involved in tasting sour.

Sweetness:
Sweetness is produced by the presence of sugar

Sugar

s, some proteins, and a few other substances. It is often connected to aldehyde

Aldehyde

An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....

s and ketone

Ketone

s, which contain a carbonyl group. Sweetness is detected by a variety of G protein-coupled receptor

G protein-coupled receptor

s coupled to a G protein

G protein

that acts as an intermediary in the communication between taste bud and brain, gustducin

Gustducin

. These receptors are T1R2+3 (heterodimer) and T1R3 (homodimer), which account for sweet sensing in humans and other animals.

Umami-ness:
The amino acid

Amino acid

Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

glutamic acid

Glutamic acid

Glutamic acid is one of the 20 proteinogenic amino acids, and its codons are GAA and GAG. It is a non-essential amino acid. The carboxylate anions and salts of glutamic acid are known as glutamates...

is responsible for umami, but some nucleotide

Nucleotide

Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...

s (inosinic acid

Inosinic acid

Inosinic acid or inosine monophosphate is a nucleotide monophosphate. Inosinic acid is important in metabolism. It is the ribonucleotide of hypoxanthine and the first nucleotide formed during the synthesis of purine. It is formed by the deamination of adenosine monophosphate, and is hydrolysed...

and guanylic acid) can act as complements, enhancing the taste.

Glutamic acid binds to a variant of the G protein-coupled receptor

G protein-coupled receptor

, producing an umami

Umami

taste.

Further sensations

The tongue can also feel other sensations not generally included in the basic tastes. These are largely detected by the somatosensory system.

Calcium:
In 2008, geneticists discovered a CaSR

CASR

CASR may stand for:*State highways in California, the highways in the US state of California*Centre for Automotive Safety Research, the road safety research centre based in the University of Adelaide*Calcium-sensing receptor...

calcium receptor on the tongues of mice

MICE

-Fiction:*Mice , alien species in The Hitchhiker's Guide to the Galaxy*The Mice -Acronyms:* "Meetings, Incentives, Conferencing, Exhibitions", facilities terminology for events...

. The CaSR receptor is commonly found in the gastrointestinal tract

Gastrointestinal tract

The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....

, kidneys, and brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

. Along with the "sweet" T1R3 receptor, the CaSR receptor can detect calcium as a taste. Whether closely related genes in mice and humans means the phenomenon exists in humans as well is unknown.

Coolness:
Some substances activate cold trigeminal receptors even when not at low temperatures. This "fresh" or "minty" sensation can be tasted in spearmint

Spearmint

Mentha spicata syn. M. cordifolia is a species of mint native to much of Europe and southwest Asia, though its exact natural range is uncertain due to extensive early cultivation. It grows in wet soils...

, menthol

Menthol

Menthol is an organic compound made synthetically or obtained from peppermint or other mint oils. It is a waxy, crystalline substance, clear or white in color, which is solid at room temperature and melts slightly above. The main form of menthol occurring in nature is -menthol, which is assigned...

, ethanol, and camphor

Camphor

Camphor is a waxy, white or transparent solid with a strong, aromatic odor. It is a terpenoid with the chemical formula C10H16O. It is found in wood of the camphor laurel , a large evergreen tree found in Asia and also of Dryobalanops aromatica, a giant of the Bornean forests...

. Caused by activation of the same mechanism that signals cold, TRPM8

TRPM8

Transient receptor potential cation channel subfamily M member 8 , also known as the cold and menthol receptor 1 , is a protein that in humans is encoded by the TRPM8 gene.-Function:...

ion channels on nerve cells

Neuron

A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...

, unlike the actual change in temperature described for sugar substitutes, this coolness is only a perceived phenomenon.

Dryness:
Some foods, such as unripe fruits, contain tannins or calcium oxalate

Calcium oxalate

Calcium oxalate is a chemical compound that forms needle-shaped crystals, known in plants as raphides. A major constituent of human kidney stones, the chemical is also found in beerstone, a scale that forms on containers used in breweries...

that cause an astringent or rough sensation of the mucous membrane of the mouth. Examples include tea

Tea

Tea is an aromatic beverage prepared by adding cured leaves of the Camellia sinensis plant to hot water. The term also refers to the plant itself. After water, tea is the most widely consumed beverage in the world...

, red wine, rhubarb

Rhubarb

Rhubarb is a group of plants that belong to the genus Rheum in the family Polygonaceae. They are herbaceous perennial plants growing from short, thick rhizomes. They have large leaves that are somewhat triangular-shaped with long fleshy petioles...

, and unripe persimmon

Persimmon

A persimmon is the edible fruit of a number of species of trees in the genus Diospyros in the ebony wood family . The word Diospyros means "the fire of Zeus" in ancient Greek. As a tree, it is a perennial plant...

s and banana

Banana

Banana is the common name for herbaceous plants of the genus Musa and for the fruit they produce. Bananas come in a variety of sizes and colors when ripe, including yellow, purple, and red....

s.

Less exact terms for the astringent sensation are "dry", "rough", "harsh" (especially for wine), "tart" (normally referring to sourness), "rubbery", "hard" or "styptic".

When referring to wine, "dry" is the opposite of "sweet" and does not refer to astringency. Wines that contain tannins and so cause an astringent sensation are not necessarily classified as "dry," and "dry" wines are not necessarily astringent.

In the Indian Ayurvedic tradition one of the 6 tastes is astringency (kasaaya).

Fattiness:
Recent research has revealed a potential taste receptor called the CD36 receptor

CD36

CD36 is an integral membrane protein found on the surface of many cell types in vertebrate animals and is also known as FAT, SCARB3, GP88, glycoprotein IV and glycoprotein IIIb . CD36 is a member of the class B scavenger receptor family of cell surface proteins...

which reacts to fat

Fat

Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...

(fatty acid

Fatty acid

In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...

s, more specifically). This receptor was found in mice

House mouse

The house mouse is a small rodent, a mouse, one of the most numerous species of the genus Mus.As a wild animal the house mouse mainly lives associated with humans, causing damage to crops and stored food....

.

Heartiness (kokumi):
Some Japanese researchers refer to the kokumi of foods laden with alcohol

Alcohol

In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....

and thiol

Thiol

In organic chemistry, a thiol is an organosulfur compound that contains a carbon-bonded sulfhydryl group...

-groups in their amino acid extracts, and this sensation has also been described as mouthfeel.

Numbness:
Both Chinese and Batak Toba cooking include the idea of 麻 (má or mati rasa), a tingling numbness caused by spices such as Sichuan pepper

Sichuan Pepper

Sichuan pepper is the outer pod of the tiny fruit of a number of species in the genus Zanthoxylum , widely grown and consumed in Asia as a spice. Despite the name, it is not related to black pepper or to chili peppers...

. The cuisines of Sichuan

Sichuan

' , known formerly in the West by its postal map spellings of Szechwan or Szechuan is a province in Southwest China with its capital in Chengdu...

province in China and of the Indonesia province North Sumatra often combine this with chili pepper

Chili pepper

Chili pepper is the fruit of plants from the genus Capsicum, members of the nightshade family, Solanaceae. The term in British English and in Australia, New Zealand, India, Malaysia and other Asian countries is just chilli without pepper.Chili peppers originated in the Americas...

to produce a 麻辣 málà, "numbing-and-hot", or "mati rasa" flavor.. These sensations although not taste fall into a category of Chemesthesis

Chemesthesis

.

Spiciness:

Substances such as ethanol and capsaicin

Capsaicin

Capsaicin 2CHCH=CH4CONHCH2C6H3-4--3- ) is the active component of chili peppers, which are plants belonging to the genus Capsicum. It is an irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact...

cause a burning sensation called Chemesthesis

Chemesthesis

, piquance, spiciness, hotness, or prickliness by inducing a trigeminal nerve reaction together with normal taste reception. The sensation of heat is caused by the food's activating nerves that express TRPV1

TRPV1

The transient receptor potential cation channel subfamily V member 1 ', also known as the capsaicin receptor and the vanilloid receptor 1, is a protein that, in humans, is encoded by the TRPV1 gene...

and TRPA1

TRPA1

Transient receptor potential cation channel, subfamily A, member 1, also known as TRPA1, is a protein which in humans is encoded by the TRPA1 gene....

receptors. Two main plant-derived compounds that provide this sensation are capsaicin

Capsaicin

from chili pepper

Chili pepper

s and piperine

Piperine

Piperine is the alkaloid responsible for the pungency of black pepper and long pepper, along with chavicine . It has also been used in some forms of traditional medicine and as an insecticide. Piperine forms monoclinic needles, is slightly soluble in water and more so in alcohol, ether or...

from black pepper

Black pepper

Black pepper is a flowering vine in the family Piperaceae, cultivated for its fruit, which is usually dried and used as a spice and seasoning. The fruit, known as a peppercorn when dried, is approximately in diameter, dark red when fully mature, and, like all drupes, contains a single seed...

. The piquant ("hot" or "spicy") sensation provided by chili peppers, black pepper, and other spices like ginger and horseradish plays an important role in a diverse range of cuisines across the world—especially in equatorial and sub-tropical climates, such as Ethiopian

Cuisine of Ethiopia

Ethiopian cuisine and Eritrean cuisine characteristically consist of spicy vegetable and meat dishes, usually in the form of wat , a thick stew, served atop injera, a large sourdough flatbread, which is about 50 centimeters in diameter and made out of fermented teff flour...

, Peruvian

Peruvian cuisine

Peruvian cuisine reflects local cooking practices and ingredients—and, through immigration, influences from Spain, China, Italy, West Africa, and Japan. Due to a lack of ingredients from their home countries, immigrants to Peru modified their traditional cuisines by using ingredients...

, Hungarian, Indian

Indian cuisine

, Korean

Cuisine of Korea

Korean cuisine originated from ancient prehistoric traditions in the Korean peninsula evolving through a complex interaction of environmental, political, and cultural trends....

, Indonesian, Lao

Cuisine of Laos

Lao cuisine is the cuisine of Laos, which is distinct from other Southeast Asian cuisines. Laos shares borders with neighboring countries and as a result, Lao cuisine has strongly influenced the neighboring cuisine of Northeastern Thailand and some Lao culinary influences have also reached...

, Malaysian, Mexican

Mexican cuisine

Mexican cuisine, a style of food that originates in Mexico, is known for its varied flavors, colourful decoration and variety of spices and ingredients, most of which are native to the country. The cuisine of Mexico has evolved through thousands of years of blending indigenous cultures, with later...

, Southwest Chinese

Southwest China

Southwest China is a region of the People's Republic of China defined by governmental bureaus that includes the municipality of Chongqing, the provinces of Sichuan, Yunnan and Guizhou, and the Tibet Autonomous Region.-Provinces:-Municipalities:...

(including Szechuan cuisine

Szechuan cuisine

Szechuan cuisine, Sichuan cuisine, or Szechwan cuisine is a style of Chinese cuisine originating in the Sichuan Province of southwestern China famed for bold flavors, particularly the pungency and spiciness resulting from liberal use of garlic and chili peppers, as well as the unique flavour of...

), and Thai

Cuisine of Thailand

Thai cuisine is the national cuisine of Thailand. Blending elements of several Southeast Asian traditions, Thai cooking places emphasis on lightly prepared dishes with strong aromatic components. The spiciness of Thai cuisine is well known. As with other Asian cuisines, balance, detail and variety...

cuisines.

This particular sensation, called Chemesthesis

Chemesthesis

, is not a taste in the technical sense, because the sensation does not arise from taste buds and a different set of nerve fibers carry it to the brain. Foods like chili peppers activate nerve fibers directly; the sensation which is interpreted as "hot" results from the stimulation of somatosensory (pain/temperature) fibers on the tongue. Many parts of the body with exposed membranes but without taste sensors (such as the nasal cavity, under the fingernails, surface of the eye ([cornea]) or a wound) produce a similar sensation of heat when exposed to hotness agents. In Asia

Asia

n countries within the sphere of mainly Chinese

Chinese cuisine

, Indian

Indian cuisine

, and Japanese

Japanese cuisine

cultural influence, Piquance

Piquance

Piquance is a sensation associated with the sense of taste. In various Asian countries it has traditionally been considered a basic taste.-Etymology:...

has traditionally been considered a sixth basic taste.

Temperature:
Temperature can be an essential element of the taste experience. Food and drink that—within a given culture—is considered to be properly served hot is often considered distasteful if cold and vice versa. For example alcoholic beverages, with a few exceptions, are usually best when served cold but soups are usually only eaten hot. A cultural example is soda

Soda

- Food and beverages :* Soft drink, a beverage product* Carbonated water, also known as "soda water"* Ice cream soda, a dessert dish* Soda cracker, or saltine cracker* Soda bread, a variety of quick bread- Science, technology, and biology :...

. In North America it is almost always preferred cold, regardless of season. In South America lukewarm soda is almost exclusively consumed in winter.

Supertasters

A supertaster is a person whose sense of taste is significantly more sensitive than average. The cause of this heightened response is thought to be, at least in part, due to an increased number of fungiform papillae.

Aftertaste

Aftertastes arise after food has been swallowed. An aftertaste can differ from the food it follows. Medicine

Medicine

Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....

s and tablets may also have a lingering aftertaste, as can certain artificial flavor compounds, such as aspartame

Aspartame

Aspartame is an artificial, non-saccharide sweetener used as a sugar substitute in some foods and beverages. In the European Union, it is codified as E951. Aspartame is a methyl ester of the aspartic acid/phenylalanine dipeptide. It was first sold under the brand name NutraSweet; since 2009 it...

(artificial sweetener).

Acquired taste

An acquired taste is an appreciation for a food or beverage that is unlikely to be enjoyed at first taste. Many of the world's delicacies

Delicacy

A delicacy is a food item that is considered highly desirable in certain cultures. Often this is because of unusual flavors or characteristics or because it is rare....

are considered to be acquired tastes.

Innervation

Taste is brought to the brainstem by 3 different cranial nerves:

Facial nerve
Facial nerve
The facial nerve is the seventh of twelve paired cranial nerves. It emerges from the brainstem between the pons and the medulla, and controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue and oral cavity...

for the anterior 2/3 of the tongue and soft palate
Soft palate
The soft palate is the soft tissue constituting the back of the roof of the mouth. The soft palate is distinguished from the hard palate at the front of the mouth in that it does not contain bone....

.
Glossopharyngeal nerve
Glossopharyngeal nerve
The glossopharyngeal nerve is the ninth of twelve pairs of cranial nerves . It exits the brainstem out from the sides of the upper medulla, just rostral to the vagus nerve...

for the posterior 1/3 of the tongue.
Vagus nerve
Vagus nerve
The vagus nerve , also called pneumogastric nerve or cranial nerve X, is the tenth of twelve paired cranial nerves...

for the small area on the epiglottis
Epiglottis
The epiglottis is a flap that is made of elastic cartilage tissue covered with a mucous membrane, attached to the entrance of the larynx. It projects obliquely upwards behind the tongue and the hyoid bone, pointing dorsally. The term, like tonsils, is often incorrectly used to refer to the uvula...

.

Disorders of taste

ageusia
Ageusia
Ageusia is the loss of taste functions of the tongue, particularly the inability to detect sweetness, sourness, bitterness, saltiness, and umami . It is sometimes confused with anosmia - a loss of the sense of smell...

(complete loss of taste)
dysgeusia
Dysgeusia
Dysgeusia is the distortion of the sense of taste. Dysgeusia is also often associated with ageusia, which is the complete lack of taste, and hypogeusia, which is the decrease in taste sensitivity. An alteration in taste or smell may be a secondary process in various disease states, or it may be...

(persistent abnormal taste)

External links

Researchers Define Molecular Basis of Human "Sweet Tooth" and Umami Taste
Statistics on Taste at National Institute on Deafness and Other Communication Disorders
National Institute on Deafness and Other Communication Disorders
The National Institute on Deafness and Other Communication Disorders , a member of the U.S. National Institutes of Health, is mandated to conduct and support biomedical and behavioral research and research training in the normal and disordered processes of hearing, balance, smell, taste, voice,...

. An informative overview with good list of references.

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

History

Recent discoveries

Taste-map myth

Basic tastes

Bitterness

Saltiness

Sourness

Sweetness

Umami

Measuring relative tastes

Functional structure

Further sensations

Supertasters

Aftertaste

Acquired taste

Innervation

Disorders of taste

Further reading

External links