First of all, let's look at a picture of the material composition contained in a tea leaf.
The two general types related to the "color" of tea are pigments and tea polyphenols.
The colored substances contained in plants can be called "pigments". There are also many pigments in tea, which are generally referred to as tea pigments.
There is a class of pigments in tea that are soluble in water, called water-soluble pigments, which mainly affect the color, taste and other quality characteristics of tea soup.
Water-soluble pigments are a general term for water-soluble pigment substances.
Tea pigments are found in fresh leaves and finished teas and are the constituents that make up the shape of the tea leaves, the tea soup and the color of the leaf bottom.
Among them, it can be divided into two categories: one is the substance that exists in the fresh leaves, that is, pigment, and the other is produced during processing, that is, the oxidation of tea polyphenols.
Naturally present in the fresh leaf leaves are anthocyanins, anthocyanins, etc.; in the tea processing, there are theaflavins, thearubicins and theaflamins, etc., and the pigment substances play an important role in the formation of tea quality.
Of course, this kind of pigment is a natural product, is positive and valuable, and we will also meet some tea leaves that are artificially dyed, and this pigment in these dyeing parts has a certain negative significance for the body and is not good.
<h1 class="pgc-h-arrow-right" data-track="10" > pigment substance</h1>
Pigments that are already present in fresh leaves include fat-soluble and water-soluble.
1. Fat-soluble pigment
Fat-soluble pigments are chemicals that mainly include chlorophyll and carotenoids, which are insoluble in water,
Fat-soluble pigments also play an important role, mainly determining the color of dry tea and the color of the bottom of the leaves, which is one of the important factors in the formation of tea quality.
A. Chlorophyll
Generally, the content of chlorophyll in yellow-green leaves and large leaf species is low, and the content of dark green and small leaf species is relatively high. In terms of production, when processing green tea, it is better to require a high proportion of chlorophyll b; while black tea, oolong tea, white tea, yellow tea, etc. have low requirements for chlorophyll content.
B. Carotenoids
The carotene in tea was first isolated and identified in tea in 1965, accounting for about 0.06% of the dry weight of fresh leaves, and the general mature leaves have a high content relative to young leaves, which has an important impact on the color and appearance of tea leaves.
In tea making, especially black tea production, carotene will be greatly oxidized and degraded to form ionone compounds, which is beneficial to the formation of the color and aroma of black tea.
(The picture above is purple bud tea)
2. Water-soluble pigment
A general term for colored substances that can be dissolved in water. Generally refers to the oxidation products of anthocyanins, anthocyanins and catechins.
The anthoclavins in the water-soluble pigment belong to the yellow pigment and are an important component of the green tea soup color.
Anthocyanins belong to the purple pigment, which have an effect on dry tea, tea soup, and leaf bottom, and also increase the bitterness of the taste.
Purple bud tea and purple crane tea are teas with particularly high anthocyanin content, and their bud leaves are purple, and the taste will be slightly bitterer than ordinary teas, and the style is unique.
<h1 class="pgc-h-arrow-right" data-track="26" > tea polyphenol oxidation product</h1>
The pigments in the tea processing process are water-soluble. There are three types of them, which are oxidized by tea polyphenols, so they have an important influence on the color and taste of tea soups.
In the core processes such as yellow tea stuffiness, black tea fermentation, and oolong tea shaking, tea polyphenols are oxidized to form theaflavin and thearubicin, which are further oxidized and polymerized into theaflavin.
(For example, the greening of oolong tea is affected by mechanical force, and some tissues of leaf margin cells are damaged, which promotes the oxidation, polymerization and condensation of polyphenolic compounds, produces colored substances and promotes the formation of aromatic compounds.) ）
Therefore, the several substances produced contain each other, that is, "you have more and I am less" . Their content ratio is very important in tea and requires a specific proportion to present the best taste, bright and clear soup color.
1. Theaflavins
Theaflavin, a golden pigment present in black tea, is the product of tea fermentation. In biochemistry, theaflavins are a class of polyphenol hydroxyl groups with the structure of tea phenol ketones.
The purifier of theaflavin is an orange-yellow needle-like crystal with a distinct orange-yellow color in its aqueous solution.
The more theaflavins, the brighter the soup color. Theaflavin has strong astringency, has a certain freshness, is weakly acidic, and is extremely active and easy to oxidize.
Since its discovery in 1957, it has been a hot topic of research, and its structural properties and physiological and pharmacological properties have also been continuously explored, and it is known as "soft gold in tea".
2. Thearubicin
Thearubicin is an orange-brown pigment present in black tea, which is the product of tea fermentation.
In biochemistry, tea red is a class of heterogeneous red or maroon-red phenolic substances with great molecular differences, which play an important role in free radical scavenging and antioxidants.
Therefore, thearubicin is a strong antioxidant that can help aging bodies resist biological oxidation.
3. Theaflamin
Theaflamin is further oxidized and polymerized by tea polyphenols, theaflavins and thearubicins, which are tan or brownish red, which is the main reason for the dark brown and dark color of black tea soups, and the chemical properties are relatively stable.
epilogue
There are many substances in tea, and these substances interact with each other and complete each other, thus forming the tone of a cup of tea, which is indispensable.
With the display of soup color substances, we can also make a basic judgment on the quality of tea, and secondly, these pigment substances have certain health value, so they are very important.