Taste is one of the five bodily senses, mainly determined by the interaction of some chemical substances with specific receptors located in numerous organelles - called taste buds, corpuscles, chalices or taste buttons - grouped in groups of 50-150 units and accommodated in distributed papillae in particular regions of the tongue Especially in the first years of life, taste receptors are also found in other regions of the oral cavity (palate, pharynx, cheek mucosa, epiglottis).
On the lingual surface we 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 on the back of the tongue;
- the acid taste stimulates specific receptors located in the basal (back) 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 mainly located in the posterior part of the pharynx.
Apart from these five basic flavors, all the others, defined as complexes, can be traced back to the combination of two or more taste bases, possibly associated with stimuli of another nature (especially 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-cut 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, albeit with different sensitivity; today, on the contrary, there are studies that suggest the gustatory independence of each single receptor cell. For some tastes, and in particular for bitterness, there are also subclasses of flavors (the existence of five types of amaro) and we should therefore not be surprised if in the near future the list of basic flavors were to further expand. On the other hand, this sense has represented an essential bodily 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 satisfy the needs of our biological machine, thanks to the contribution of the so-called specific hunger or appetite (such as calves that lick iron pipes of their cage or others who do the same with salt).
But what difference is there, exactly, between flavor and taste?
Taste is the sensation produced by certain substances on the receptors of our tongue.
As explained in the article, among the countless types of possible flavors there are four universally recognized as fundamental: sweet, salty, sour, bitter. All the others, defined as complex, can be traced back to combinations of two or more fundamental flavors.
Taste, on the other hand, is something more complex; in fact, it represents that "set of sensations felt with the four fundamental flavors, but also with other sensory spheres, such as tactile, thermal, chemical stimuli and above all with the retronasal olfactory sensation, also known as the gustatory olfactory sensation. D" on the other hand, in winter, when the nose closes due to a cold, the taste (pardon, the taste!) of food is negatively affected.
The integrated set of stimuli coming from the taste receptors is associated, at a central level, with signals of different nature (thermal, tactile, painful, olfactory ...), giving rise to a real gustatory spectacle. During some experiments, for example, it was noted that a sweet and bitter solution appeared sweeter and less bitter if it was added with salt, while the acidity and bitterness were contrasted by the sweet. Similarly, from personal experience, we know that cold milk has a different flavor from the heated one (variations in the temperature of the tongue cause different taste perceptions), just as stale bread has a different flavor than the fresh one (in order to perceive the taste of a substance, this must be in a watery environment, therefore it must be previously solubilized by mucus and saliva).
The number of taste buds, high in childhood, decreases with advancing age and this explains, at least in part, the greater acceptance of the adult of foods systematically rejected by the little ones, such as bitter vegetables.
