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What substances are contained in tea?
If someone asks you this, you may open your mouth and answer: "There are tea polyphenols in tea leaves..." The first thing you mentioned may be tea polyphenols. It can be seen that we are not strangers to tea polyphenols.
There are more than 700 known compounds in tea that have been isolated and identified, and tea polyphenols are its most important characteristic ingredients, so they are often talked about by us. However, how many tea lovers really understand tea polyphenols? I'm afraid many people can't even say what ingredients tea polyphenols contain, right?
So, xiao understand today to briefly sort out the relevant knowledge points of tea polyphenols and share it with you. In order to facilitate memory, xiaoyi simplifies it as much as possible!
▲Tea polyphenols
1, tea polyphenols are not a substance, but a variety of substances. It refers to the many different phenols and their derivatives contained in tea, referred to as "polyphenols" or "tea polyphenols".
2. Tea polyphenols mainly contain four categories: catechins (flavanols), flavonoids, anthocyanins, and phenolic acids, of which catechins account for the majority, accounting for about 70% of the total polyphenols.
First, let's look at a relationship diagram, so that everyone can see the composition of tea polyphenols at a glance. In fact, each category can also be subdivided below, if it is not a researcher, there is no need to remember too detailed!
▲Tea polyphenols main substance composition diagram, the proportion of substances in the figure is the proportion of the dry weight of the tea leaves (understand the tea emperor chart, click to view the large picture)
3. Catechin is a white solid, easily soluble in hot water, methanol and other solvents.
4. Catechin is easy to oxidize, polymerize and condense under the action of light, high temperature, alkaline or oxidase, and can be automatically oxidized into yellow-brown substances in the air.
5. Flavonoids are mostly bright yellow crystals, and their aqueous solutions are greenish yellow, so they have a greater effect on the formation of green tea soup color.
6. The anthocyanins in general tea only account for 0.01% of the dry weight, and the purple bud tea can reach 0.5-1%; while the anthocyanins account for about 2-3%.
7. Anthocyanins, also known as anthocyanins, are a class of water-soluble natural pigments widely present in plants in nature, which are flavonoid compounds. It is also the main coloring substance in the petals of plants, and the colorful colors such as fruits, vegetables, and flowers are mostly related to it.
Plants with high anthocyanin content in nature are mostly purple, such as blueberries, grapes, eggplant, purple potatoes, purple cabbage, and the familiar purple juan tea.
▲Purple Juan tea tree
8. Anthocyanin, originally colorless, can be completely oxidized into colored oxides in black tea fermentation. After hydrochloric acid treatment, the anthocyanin can also form a red substance. Therefore, anthocyanins are also known as "occult anthocyanins".
9. The phenolic acids in tea are mostly white crystals, easily soluble in water and aqueous ethanol, and they are mostly condensed derivatives of gallic acid, caffeic acid and chicken nanoic acid.
10. Phenolic acids are indispensable substances for the synthesis of ester catechins, and the product of ester catechins that are continuously hydrolyzed is a factor involved in the formation of tea soup taste.
The complex changes of polyphenols in the production process of black tea (especially the fermentation process) can be roughly divided into three parts: 1, unoxidized polyphenols, mainly residual catechins, and mainly ester catechins; 2, non-water-soluble transformation products; 3, water-soluble oxidation products, mainly theaflavins (tf), thearubicin (tr), theaflamin (tb).
▲Changes of black tea polyphenols in the production process (understand the tea emperor drawing, please indicate the source when reprinting)
The above is the main knowledge point about tea polyphenols, but these are only from the perspective of chemical composition to do combing, there are many knowledge points about the efficacy of tea polyphenols, we will talk about it later!
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