Friday, June 26, 2020

Tea Encyclopedia Why is tea bitter? Why is it sweet?

Everyone who has drunk tea knows that in the mouth of tea, the bitterness comes first, and then it slowly returns to sweetness, as does Pu'er tea. So the question is, what causes the bitter taste of tea? Why is tea sweet?

We feel that tea is very bitter because the tea leaves contain bitter substances. Such substances in tea are mainly caffeine, theobromine, theophylline, anthocyanins, tea saponins, bitter amino acids and some flavanols. This tea is very bitter, indicating that the alkaloids contained in it dominate the tea soup. (Alkaloids refer to a class of nitrogen-containing organic compounds derived from the biological world. They have similar properties to alkalis and can combine with acids to form salts. Most are optically active and have a special and significant physiological effect on the central nervous system of animals. )

In general, the alkaloid contained in tea has the highest content of caffeine, generally 2%-4%. Caffeine has a bitter taste, and the threshold is low. Chen Zongdao et al. (1992) showed that temperature and pH have an effect on bitter taste sensitivity. As pH and temperature increase, the threshold decreases and the sensitivity increases. The content of caffeine varies greatly in different parts of the tea tree, with the most leaves and fewer stalks, which declines with the aging of leaves in new shoots.

In addition to the bitter taste, some people will feel obvious astringency when drinking tea. Astringency: A food ingredient that stimulates the mouth and causes a feeling of convergence when the protein solidifies. Astringency is not the basic taste of food, but the result of stimulating tactile nerve endings. The astringency is the result of the action of tea polyphenols, which stimulate the mouth and cause protein secretion on the tongue surface, forming a sense of layering.

The bitter taste of tea is caused not only by the internal substances of the tea, but also by external factors. The length of the year in which the tea is stored, the environmental factors of the place of origin of the raw materials, the taste of spring tea is more bitter than the autumn tea, the storage environment, the production process and other factors can affect the bitterness of the tea.

The bitterness of caffeine will not be left in the tongue, and will be quickly dissipated. This bitter taste is the basis of "returning to sweetness". The astringency of the tea soup is because the tea soup contains tea tannins. Tea tannins have an astringent effect, which can solidify the protein of oral single-cell fungi and further converge the local oral muscles. When the bitterness of tea tannin is gone, the astringent transforms, and the local muscles of the oral cavity begin to recover, and the feeling of regenerating appears.

The tea soup contains a certain degree of sweetness, and most of the tea leaves exhibiting sweetness are soluble monosaccharides or disaccharides, such as biructose, glucose, sucrose and maltose. Although sweetness is not the main flavoring substance of tea soup, sweetness can weaken the bitterness to a certain extent and ease the stimulation of tea soup.

Sugars do not produce a sense of sweetness and rejuvenation, which is also the main difference between sweetness and sweetness. Sweetness comes directly, and sweetness is slowly released after the bitter taste.

When the bitter-tasting substance no longer keeps the tongue, it can cause the taste to change and the "illusion" of taste to appear sweet. This illusion should be a reflection of human instinct needs.

Thousands of people drink tea differently, and everyone's perception of tea is also different. The bitter taste of tea is also affected to a certain extent by personal subjective feelings. But overall, the bitter taste and sweetness of tea is its unique taste. Life is like tea, eating bitterly and bitterly, only to be a man, to taste all the bitterness and to come.

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