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How is the color, taste and aroma of tea produced? From a piece of fresh tea

Apr 28,2024 | taetea

Drinking tea is drinking an aqueous solution, which is actually similar to vegetable soup.
Tea is mainly water and various substances that have color, taste and aroma.
Where do these substances come from? What exactly is in a piece of tea? What exactly do they do?

Tea polyphenols
Tea polyphenols in tea are an important class of compounds, accounting for 20% to 35% of the total dry matter of tea.
Tea polyphenols include four major categories of substances: catechins, flavonoids, anthocyanins, phenolic acids and depsipphenolic acids.
Tea polyphenols are an important difference between tea and other plants, and also the primary component of tea's health care function.
The content of polyphenols in tea is affected by many factors, including environment, tea tree variety, and degree of tenderness.
Among them, catechin accounts for about 70% of the total amount of tea polyphenols, and is an important component that affects the color, aroma and taste of tea.
The protein content in tea leaves accounts for 20% to 30% of the dry matter, but only 1% to 2% of the water-soluble protein can be directly utilized.
This part of water-soluble protein is one of the components that form the taste of tea soup.
amino acid
Amino acids in tea are the basic substances that make up protein, and their content accounts for 1% to 4% of the total dry matter.
It has been found that tea contains 26 kinds of amino acids, including theanine, glutamic acid and aspartic acid.
The content of amino acids in different seasons shows a trend of high in spring, low in autumn and middle in summer, which is why spring tea is more refreshing.
Amino acids are the main contributors to the taste and aroma of tea. They can neutralize the bitterness of polyphenols and caffeine, and at the same time evolve a variety of charming aromas. They are an indispensable part of high-grade tea.
The alkaloids in tea include caffeine, theobromine and barkine.
Among them, the content of caffeine is the largest, accounting for about 2% to 5% of the total dry matter.
Caffeine has a bitter taste, and the content of different parts of the tea tree varies greatly, with the most in the leaves and less in the stems. Summer tea has a higher content than spring tea, but the content varies with leaf aging and seasonal changes.
Caffeine is easily soluble in water, is an important substance that forms the taste of tea, and can also be used as one of the characteristics to distinguish true and false tea.
Caffeine has a variety of pharmacological effects on the human body, such as refreshing, diuretic, promoting blood circulation and helping digestion.
Tea contains a variety of sugars, including water-soluble monosaccharides and disaccharides, and water-insoluble polysaccharides such as starch, cellulose, hemicellulose, and lignin.
The content of these sugars accounts for about 20% to 25% of the total dry matter of tea.
Among them, polysaccharide is an important component to measure the tenderness of tea. When the tea tenderness is low, the polysaccharide content is high; when the tenderness is high, the polysaccharide content is low.
Tea leaves also contain substances such as pectin, which are metabolites of sugar, and their content accounts for about 4% of the total dry matter.
These substances are beneficial to the manual kneading and shaping during the tea processing process, and also have a great influence on the viscosity of the tea soup.
Water-soluble pectin is one of the main components that form the thickness and glossiness of tea soup.
organic acid
There are many kinds of organic acids in tea, and the content is about 3% of the total dry matter.
Most of these organic acids are free organic acids, such as malic acid, citric acid, succinic acid and oxalic acid.
Organic acids formed during tea making, such as palmitic, linoleic, and vinyl acids, are also important.
The organic acid in tea is one of the main components of tea aroma. It has been found that there are 25 kinds of organic acids in the aroma components of tea.
Although some organic acids themselves have no aroma, they are converted into aroma components after oxidation, such as linoleic acid, etc.; some organic acids are good adsorbents for aroma components, such as palmitic acid.
Lipid substances in tea include fat, phospholipids, glycerolipids, sugar esters and thioesters, etc., accounting for about 8% of the total dry matter.
These substances have a positive effect on the formation of tea aroma.
In the protoplasm of the tea tree body, lipid substances can regulate the penetration of substances and regulate the substances entering cells.
Pigment is one of the main components in tea, which can be divided into two types: fat-soluble and water-soluble.
Fat-soluble pigments mainly include chlorophyll, lutein and carotene, etc., which are insoluble in water and play an important role in the color of tea.
Water-soluble pigments include flavonoids, anthocyanins, and oxidation products of tea polyphenols, which also affect the color of tea leaves.
The color of the six major teas is closely related to the content, composition and transformation of pigments in the tea.
Aromatic substances
Aromatic substances refer to the general term of volatile substances in tea.
Although the content is not much, the types are very complex. According to analysis, there are more than 300 kinds of aroma components in tea.The main components include alcohols, phenols, aldehydes, ketones, acids, esters, lactones, nitrogen-containing compounds, sulfur-containing compounds, hydrocarbons, and oxides.
The aromatic substances in fresh leaves are mainly alcohol compounds. The low-boiling-point green leafy alcohol has a strong green grass smell, and the high-boiling-point agaralool and phenylethyl alcohol have the characteristics of light fragrance and floral fragrance.
Tea is rich in vitamins, and its content accounts for 0.6% to 1% of the total dry matter.
Vitamins are divided into water soluble and fat soluble.
Fat-soluble vitamins include vitamin A, vitamin D, vitamin E, and vitamin K, among which vitamin A is more abundant.
The water-soluble vitamins include vitamin C, vitamin B1, vitamin B2, vitamin B3, vitamin B5, vitamin B11, vitamin P and inositol, among which vitamin C has the most content.
Certain nutrients can be absorbed by drinking tea, but fat-soluble vitamins cannot be directly absorbed and utilized.
In summary, the different kinds of chemical components in tea interact with each other to create the unique aroma and taste of tea. Therefore, knowing these ingredients is crucial to making high-quality tea.