Tea
<h1 class="pgc-h-arrow-right">01.</h1>
The formation mechanism of "back sweet" and "back sweet" of tea soup is different:
[Sweetening]: It is a physical effect, mainly from the sweet substance of the tea itself. It can be felt directly by the taste buds.
[Huigan]: It is a chemical action, which is transformed from bitter taste. When the bitter polyphenol substances in the tea leaves, and the proteins in the oral saliva, are combined with each other and transformed, a new taste is produced, and the throat remains for a long time, which is [back to the sweet]. People often describe the feeling of "returning to sweetness" as: slightly bitter in the mouth, sweet in the aftertaste, bitter and sweet, and so on.
<h1 class="pgc-h-arrow-right">02.</h1>
<h1 class= "pgc-h-arrow-right" > the "sweetening" of the tea soup is different from the "sweetening", and the substance produced is different:</h1>
1. The three main substances that produce [sweetening]:
In the book "Chinese Tea Dictionary" edited by Professor Chen Zongmao, there are 3 major types of substances formed by the sweetness of tea soup:
(1) Monosaccharides and oligosaccharides (soluble sugars) in tea leaves present in a free state.
(2) Sweetened amino acids.
(3) Intermediate product of catechin biosynthesis.
The carbohydrates in tea are very rich. They have the main functions of providing nutrients for tea plants, promoting the growth of branches and leaves, providing energy required for tea plants to breathe, and so on.
(1) Present in tea leaves in a free state: monosaccharides, oligosaccharides (soluble sugars):
These monosaccharides and oligosaccharides (soluble sugars) present in the tea in a free state: they are easily soluble in water, accounting for about 4% to 6% of the dry matter of tea leaves, and are the main source of tea sweetness. There are: glucose, galactose, fructose, rhamnose, maltose, sucrose, etc.
Subdivision of soluble sugars: monosaccharides, disaccharides.
Monosaccharides: It is a sugar substance that can no longer be hydrolyzed. The main monosaccharides are: fructose, glucose, galactose, mannose, arabinose, rhamnose, ribose, xylose, etc. 8 kinds. It is the main substance in the formation of the sweetness of tea soup.
Disaccharides: refers to the sugar substances produced by 2 identical, different, monosaccharides, through a variety of chemical reactions. It can eventually hydrolyze into a monosaccharide substance after producing a variety of chemical reactions. The main disaccharides are: sucrose, maltose, 3 sugars, cottonose, 4 sugars, sumacose, and so on. It is the main substance of the sweetness of tea soup.
(2) Sweetened amino acids (free amino acids):
Amino acids are the basic elements of the synthesis of proteins. Inside the tea leaves, the sweet free amino acids mainly include: threonine, serine, alanine, glycine, hydroxyproline, etc. There is also a part formed in the process of tea processing, mainly including: tryptophan, methionine, leucine, isoleucine, tyrosine, phenylalanine, valine, and so on. These sweetened free amino acids increase the freshness, sweetness, fullness of the tea leaves, and some amino acids are slightly sour.
(3) Intermediate products of catechin biosynthesis:
Catechins are also commonly referred to as "tea tannins". It belongs to the flavanol substances, is the main component of polyphenols in tea, accounts for about 80% of tea polyphenols, and is the main source of bitter taste in tea. Intermediate products that can produce sweet, catechin biosynthesis, include: dihydrochaldone compounds and derivatives, beanin isomeric compounds, etc. These sweet catechin intermediate products can increase the sweetness and sweetness of the tea leaves.
Biluochun
2. [Returning to sweetness] means to be bitter and sweet:
(1) [Back to gan] is the result of the combination of tea polyphenols and proteins:
Tea contains tea polyphenols, which can be combined with proteins to form an impermeable membrane in the oral endoplasm, and the local muscle contraction of the oral cavity causes the astringency of the mouth, so that we feel that the tea we have just drunk will have a bitter feeling. If the polyphenol content of tea is more appropriate, forming a membrane with only one or two layers of single-molecule layer or bilayer layer, this membrane is moderately thick and thin, and there is an astringency in the mouth at the beginning, and later after the membrane ruptures, the local muscles of the oral cavity begin to recover, and the astringent transformation is presented. ”
(Source: Professor Wang Yuefei, Department of Tea Science, Zhejiang University)
(2) The main substances that produce [huigan]:
▷Flavonoids:
Drawing on the fact that "olives are significantly stronger", comparative analysis is carried out with tea leaves. Because the "sweetening" effect of olives is the most powerful and obvious, and through experimental analysis, it is found that the content of flavonoids, polyphenols and substances in olives is higher than that of other plants. This method is used to compare and identify tea leaves. The higher the content of flavonoid substances in tea leaves, the more obvious the "back to sweetness" of tea soup.
▷Theanine:
Theanine, also known as glutamine, has a sweet taste and belongs to the class of free amino acids. It is the main substance of tea raw and sweet. The theanine content in the new tea is about: 1% to 2%, and its content decreases with the fermentation process.
▷Polyphenols:
Polyphenols, accounting for 18%-36% of the total dry matter of tea leaves. In most cases, it has a direct bitter taste, and after transformation, it has a sweet taste. The content of polyphenols is directly proportional to the degree of "back to sweetness" of tea soup. Some teas, the more bitter the more [sweet].
▷Organic acids:
Organic acids account for about 3% of the total dry matter of tea. And the content will increase during the tea making process. The organic acids in tea stimulate the secretion of oral salivary glands, making people feel "back to Ganshengjin".
▷Tea polysaccharides:
Tea polysaccharides are 1 complex category of "acid glycoprotein complex", which is composed of: sugar, pectin, protein (more than 20 kinds of amino acids), minerals, trace elements, etc. Tea polysaccharide is the abbreviation of "tea polysaccharide complex", which accounts for about 20% of the total dry matter of tea leaves. Tea polysaccharide substances, itself has no sweetness, but has a certain viscosity, tea soup will stay in the mouth. At this time, the amylase in the saliva will decompose the tea polysaccharides in the tea soup and transform them into maltose. In this transformation time, people have a feeling similar to "returning to Gan".
jasmine tea
<h1 class="pgc-h-arrow-right">03.</h1>
< h1 class="pgc-h-arrow-right" > finally review the main content of this article:</h1>
1. The difference between tea soup back sweet, sweet back: back sweet is direct, back sweet is tea polyphenols and protein binding.
2. The formation mechanism of "back sweet" and "back sweet" of tea soup is different:
3. The "sweetening" of the tea soup is different from the "sweetness", and the substance produced is different.
4. [Back to sweet]: it is the result of bitter sweetness, which is the result of the combination of tea polyphenols and protein.
5. The 3 main substances of [sweetening]: monosaccharides and oligosaccharides (soluble sugars) that exist in a free state and are in tea. Sweetened amino acids. An intermediate product of catechin biosynthesis.
【Thank you for paying attention to the headline number: leisurely tea tasting】
Rizhao green tea