Now only four of seven types of feeling listed by Lomonosov are considered as the purely flavoring. "Caustic" taste appears as a result of irritation of the terminations of painful nerves in an oral cavity. "Sharp" is defined by impurity of olfactory feelings. The taste designated by Lomonosov, "sourish as in unripe fruits", is, apparently, the knitting taste about which origin we already spoke.
Now assume that receptor sites of flavoring cages are rather specific to various types of flavoring incentives, and each flavoring cage can have some types of receptor sites. Interaction of molecules of a flavoring cage leads to its depolarization that is connected, obviously, with change of permeability of sites of a membrane on which receptor places are located.
It is known that at mixture of red and yellow color there is a feeling of the orange; red and green – yellow, violet and green – blue color. An eye is not able to spread out the mixed colors to the components making them.
In this way sour and sweet substances can cause difficult decomposable feelings sweet-sour, peculiar to many grades of apples or fruit drinks. Sour and salty substances can cause emergence of feeling sour-salty which example taste of a cucumber brine can be. Bitter and sweet merge hardly, but bitter cocoa in mix with sugar causes the peculiar conjoint feeling peculiar to chocolate. And here the slitiya bitter with salty and especially bitter does not happen to the sour at all. Mixes of bitter and salty, bitter and sour substances are extremely unpleasant on taste.
It is easy to be convinced of it if to take a slice of unleavened white loaf in a mouth. Starch which is not dissolved in water and is the main carbohydrates containing in such bread, has no taste. Once you chew bread, that is to bring it into contact with a saliva, it develops a distinct sweetish taste, a sign of that the part of starch was split by saliva enzymes to glucose.
After the substance fell victim to the tongue, at first there is a feeling of a touch (that is tactile feeling), and only then – flavoring feelings in the following order: on a language tip the first shows salty taste, behind it sweet, sour and after all bitter; on the basis of language – first of all bitter, then salty and after all sweet. These distinctions too can influence the general feeling of taste somehow.
Now clear are movements of language at hit in a mouth of tasty food – smacking, savoring (by the way, in Polish the word "relish" means taste). At the movement of a tip of language along a hard palate there is a spreading of food on its surfaces which are in structure of food the dissolved particles get into depth of trenches and grooves of language thanks to what their action on flavoring receptors is accelerated and amplifies. Movement of food on surfaces of language has a great influence and on duration of flavoring feeling. Professional tasters use these methods.
All building of a gastronomy which has that physiological value is based on the phenomena of contrast of tastes, their compensation and traces that good, pleasant taste of food promotes its digestion, strengthening release of digestive juice and causing the mood so favorable for the normal course of all corporal processes in an organism.
At research of neurophysiology of flavoring feelings it is necessary to consider the following fact. As true flavoring feelings it is possible to consider only what arise at irritation of flavoring receptors. But along with flavoring kidneys in an oral cavity there is a large number of other sensitive educations which excitement causes feeling of a touch and pressure (tactile receptors), pain and temperature feelings. The substances which are in a mouth can be also a source of olfactory feelings. Any piece of food influences many, and sometimes all these educations, and it is also accepted to call all scale of these feelings taste.
There is an active and passive perception of taste of the substances getting to a mouth. In the first case it is about simple contact of these substances with a surface of language or a throat, in the second – about the feelings occurring at the spreading of substance on a sensitive surface which is made at the movements of language. The qualitative difference thus in flavoring feelings is not present, but taste becomes more distinct.