Taste

The taste is one of the five direction of the Man, that which makes it possible to analyze the savor of food put in mouth by the subject.

The sensory cells specialized in the gustation are gathered in spherical structures called gustatory buds located mainly in the papillae. At the Man, there are some approximately: 4000 (extremes: 500 -: 20000). The gustatory buds are mainly localized on the dorsal face of the language (75  %), the remainder being distributed on the soft palate, the pharynx and even the upper part of the esophagus. On the language, the buds are located in the epithelium at the level of the lingual papillae (caliciform, fungiformes and thread-like). Each bud counts 50 with 150  sensory cells surrounded by cells of support. The gustatory bud opens towards the oral cavity by a pore.

Primary savors

In the 19th century, the physiologist Adolph Fick defined four primary or fundamental savors which would be related to four types of sensory receivers and four localizations on the language. One defines of them sometimes five, by adding the Umami (tasty), identified in 1908 by Japanese: Certain theories call upon a less segmented and more synthetic design, based on a total perception.

Thus as of 1939, Carl Pfaffmann called into question this traditional classification, but 1980 should have been awaited so that it is shown definitively that the sapid molecules all are recognized in a specific way by the brain.

According to Hanig (1901), the primary education tastes are perceived by all the papillae, whatever their localization, but the sensitivity to a particular taste is larger in certain areas of the language:

  • the lingual land-mark behind of V (bases) => nerve glosso-pharyngien;

  • salted by the point and the edges of the language (in front of V lingual) => lingual nerve/chorda tympani/facial nerve;
  • acid by the edges of the language => lingual nerve/chorda tympani/facial nerve;
  • sweetened by the point of the language => lingual nerve/chorda tympani/facial nerve.

The classification of the tastes in four primary education tastes is reducing. There are other savors which do not enter this classification:

Moreover, the gustatory answers vary according to the individuals. Thus, for example, the taste of the Phénylthiocarbamide (bitter savor) is not perceived by approximately 35  % of the population. The sapid molecules generate a feeling only beyond certain concentration, one speaks about thresholds of detection.

  • salted: 10  mm;

  • sweetened: 10  mm (saccharose 20  mm);
  • acid: 900  µM (acid citric 2  mm);
  • bitter: 8  µM (quinine 8  µM, strychnin 100  Nm).

Bitter savors are those which have the threshold of detection low. Possible adaptive advantage if it is considered that the majority of the vegetable poisons are bitter.

The various tastes are recognized by specific cells using receivers TRC (50 to 150 receivers by buds). These various cells gather in bud whose composition varies according to the localization. In fact some are the gustatory methods (salted, bitter, sweetened, acid), the histology of the gustatory buds is the same one. Those act like receivers and transmit to the nervous fiber to which they are connected information. It is the variation of this innervation at the lingual level which allows the integration of the gustatory message. The former portion of the language is innervée by the facial nerve (VII (a)) and préférenciellement conveys information in answer to a sweetened stimulation. The posterior portion of the language is innervée by the nerve Glossopharyngien (IX) and the épiglotte by the vagus or pneumogastric (X), this area has a tendency to transmit the message amer.
It is then on the level of the cerebral Cortex, in the area préfrontale of the Cerveau, that all this information (with the Odorat) is processed by the organization.

Related concepts

Sapidity does not constitute approximately that 10% of the whole of the sensory information perceived at the time of the setting in mouth of a food. In addition to the texture and the temperature of food, also enter in account:
  • flaveurs : the retro-nasal smell i.e. the excitation of the olfactive receivers of the nose by molecules released at the time of tasting, or simply during swallowing. The direction of the Sense of smell between thus concerned in the determination of savors: a nose “stopped” following a cold reduces faculty considerably to taste, because that prevents retro-nasal circulation and thus the identification of the aromatic characteristics.
  • pricking : activation of receivers of the pain by certain molecules like the Capsaïcine (receiving TRPV1) of the Pepper or the Piperin of the Pepper. This feeling is known also under the term of feeling of Pseudo-heat .
  • freshness : activation of the receivers of the cold of the oral cavity by connection of molecules of menthol with the ionic channels of type TRP (TRPM8) also activated by the painless cold (temperatures ranging between +5 and +30°C). This feeling is known also under the term of feeling of Pseudo-heat . This effect can also be caused by various synthetic substances. A reaction Endothermique can also generate, in the mouth, a real feeling of cold, as during dissolution of certain sugars (Fructose, Mannitol) and Polyol (Xylitol and Érythritol) especially when the latter are ground very fine, thus offering a large surface for dissolution.
  • astringency : activation of the tactile receivers by an action of tightening of fabrics under the action of certain substances like the Tannin S of the wine.

The French vocabulary maintains a confusion on the level the term “taste” because, in the language running, one says for example “taste of strawberry” or “taste of smoke” to indicate flavors, when they are perceived by Retro-smell. The term Arôme, which would be appropriate in fact, is under-utilized and often included/understood like added or even synthetic flavor (as in “Chewing-gum flavor banana”). Moreover, in certain circumstances, the flavor term would be very surprising (one says “this wine has a taste of stopper rather” than “this wine has a flavor of stopper”, whereas, sensoriellement speaking, this last formulation would be the good one. One will be able to speak about a “wine bouchonné” to solve the dilemma). The direction of the word taste thus varies according to its context.

The taste, that is learned

The taste is very cultural, it is very depend on the dietary habits: a child, for example, who was accustomed to eat sweetened, and to nibble as of his more young age, will have enormously evil to change practices: all that is a little bitter for example will be the subject of a rejection.

The more so as all this starts as of gestation: the fetus/child is accustomed to receive molecules related to food consumed by his/her mother

References

Bonds

External bonds

taste|taste
  • the European ones of the Taste

Fiu-vro: Maitsminõ Simple: Taste

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