Anyone who has ever tried mints or gum knows the feeling of coldness in the mouth. But few people know why there is a pleasant chill in the mouth?
It is known that we feel cold with cold receptors, which are located on the skin and mucous membranes of our body. If the temperature drops below a certain level, then a nerve impulse is sent to the brain, after which the vessels narrow, and less blood is supplied. However, these receptors react not only to temperature, but also to certain substances, one of which is menthol contained in peppermint. In fact, menthol does not cool the mouth, it only creates the illusion of being cold. It makes all our receptors partially insensitive, except for the cold ones. And they, in turn, send a nerve impulse to the brain, as when exposed to low temperatures.
But red hot pepper, falling on the tongue, causes a "fire" in the mouth due to the substance capsaicin contained in this spice, which stimulates the sensitive system of trigeminal nerve receptors.
Most of the capsaicin is found on the inner walls of the pepper. That is why the burning effect does not occur immediately after biting the pepper, but a little later. In contact with the mucous membrane, even the smallest doses of capsaicin affect certain nerve endings in the tongue, the so-called C-fibers, which react to temperature or mechanical and chemical stimuli. The intense burning sensation goes away only when the hot pepper reaches the esophagus, which contains much less C-fibers. However, for all its "flammability", capsaicin is more useful than harmful - it stimulates the secretion of gastric juice and improves appetite. In addition, capsaicin, which is responsible for the pungent taste and irritating effect of hot pepper, causes massive death of malignant cells by acting on mitochondria - organelles that provide cells with energy.