![]() ![]() Since caffeine has a stimulant effect on the central nervous system (CNS), it can ward off drowsiness and increase the capacity for mental or physical labor. The main effects of caffeine include increased alertness and a mild diuretic effect. Among teas that have been roasted at high temperature, such as Hojicha, the caffeine is sublimated (changed directly from a solid to a gaseous state) and is said to decrease. Although there is not a great difference in caffeine content depending on the period in which the tea is picked, such as between Ichibancha and Nibancha, similar to catechin and amino acid (theanine), there is a higher caffeine content in young shoots and mature leaves tend to contain less. This is an effect of caffeine, which is present in tea. Since theanine does not break down if it is not exposed to light, teas high in theanine and low in catechin may be produced by using covered culture.ĭrinking tea when tired from work or study can make a person feel refreshed. Theanine is broken down when exposed to light, producing ethylamino, which in turn changes into catechin. Theanine is produced in the roots of the tea bushes, and migrates to the leaves. In teas that have been grown using cover culture to block out most light, such as Gyokuro, the generation of catechins is suppressed, giving such teas a lower catechin content than Sencha (approximately 10% as polyphenols). The catechin content of young shoots (first or second leaf) is higher than mature leaves (third or fourth leaf). Ichibancha has a catechin content of approximately 12-14%, while Nibancha has a catechin content of approximately 14-15%. This is what gives oolong and black teas their distinctive reddish color. In oolong and black teas, the action of oxidizing enzymes produces oxidized polymers (complex catechins, such as theaflavins and thearubigins).Unlike catechins, which are colorless in aqueous solution, these oxidized catechins become orange or red. In green tea, since the process for making crude tea involves halting the action of oxidizing enzymes, most of the catechins remain unoxidized. In addition, during the manufacturing process for tea beverages, owing to heat processing, some catechins change form.Įpigallocatechin gallate → Gallocatechin gallateĬatechins oxidize extremely easily. There are four main types of catechins found in tea leaves. Michiyo Tsujimura in 1929 at RIKEN (The Institute of Physical and Chemical Research) in Japan. Catechin was first isolated from the Indian plant extract catechu (from the plant acacia catechu, a tree of the fabaceae family, acacia genus), from which it derives its name. Prevention of fetal neural tube defects (NTD)Ĭatechins are a type of polyphenol and are the main astringency component in green tea, long known as tannins. Relaxation effect (promotes α wave production) Tooth decay prevention, antibacterial effectīad breath prevention (deodorizing effect) ![]()
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