Taste is one of the five bodily senses, determined mainly by the interaction of certain chemicals with specific receptors located in numerous organelles - called taste buds, corpuscles, goblets or gustatory buttons - grouped in small groups of 50-150 units and received in distributed papillae in particular regions of the language. Especially in the first years of life the taste receptors are also found in other regions of the oral cavity (palate, pharynx, cheek mucosa, epiglottis).
On the lingual surface one can distinguish regions specialized in the recognition of different flavors. The main and traditional characteristics (or bases) of taste are four:
- the bitter taste is recognized by the papillae present in the back of the tongue;
- the acid taste stimulates specific receptors located in the basal (posterior) part of the tongue;
- the salty taste is perceived in the lateral and apical part (tip) of the tongue;
- the sweet taste sensitizes the apical part of the organ.
Alongside these four universal flavors, a fifth has recently been introduced, called umami .
The umami receptors are located mainly in the posterior part of the pharynx.
Outside of these five fundamental tastes, all the others, defined complex, can be traced back to the combination of two or more bases of taste, possibly associated with stimuli of other nature (above all olfactory). The spicy taste of a food is instead evoked by the stimulation of pain receptors.
In any case, this sensory subdivision is not clear and the physiological mechanism that leads to the perception of taste is rather complex; until a few years ago, for example, it was believed that every single taste cell could recognize more than one taste, even if with different sensitivity; today, on the contrary, there are studies that suggest the gustatory independence of every single receptor cell. For some tastes, and in particular for bitterness, there would also exist subclasses of flavors (the existence of five types of bitter has been demonstrated) and we should therefore not be surprised if in the near future the list of basic flavors should further expand . On the other hand, this sense has represented an essential body quality in the history and evolutionary process of man. Thanks to it, we can not only recognize the presence of potentially beneficial or toxic substances (bitter taste), but also meet the needs of our biological machine, thanks to the contribution of the so-called specific hunger or appetite (like calves that lick iron pipes of their cage or others that do the same with salt).
But what difference exists, exactly, between taste and taste?
Taste is the sensation produced by certain substances on the receptors of our language.
As explained in the article, among the innumerable types of flavor there are four universally recognized as fundamental: sweet, salty, sour, bitter. All the others, defined complex, can be traced back to combinations of two or more fundamental flavors.
Taste, on the other hand, is something more complex; it represents in fact that set of sensations perceived with the four basic flavors, but also with other sensory spheres, such as tactile, thermal, chemical stimuli and above all with the retronasal olfactory sensation, also called gustatory sensation. On the other hand, in winter, when the nose closes due to a cold, the taste (pardon, taste!) Of food is negatively affected.
The integrated set of stimuli from the taste receptors is associated, at the central level, with signals of different nature (thermal, tactile, pain, olfactory ...), giving rise to a real gustatory show. During some experiments, for example, it was noticed that a sweet and bitter solution appeared sweeter and less bitter if it was added with salt, while acidity and bitterness were contrasted by the sweet. In the same way, from personal experience, we know that cold milk has a different taste from the heated one (temperature variations of the tongue cause different taste perceptions), just as stale bread has a different flavor than fresh (to be able to perceive the taste of a substance, this must be in a watery environment, then be previously solubilized by the mucus and saliva).
The number of taste buds, elevated in childhood, decreases with advancing age, which explains, at least in part, the greater acceptance by adults of foods systematically rejected by children, such as bitter vegetables.
