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Do you know what kind of ingredients green tea contains?
Of course, it is not necessary to be familiar with the ingredients, but if you know that, you can see what kind of effects you can get from green teas.
Unlike black tea, oolong tea and hojicha, green tea are created without fermentation(oxidation) and heating, the change of ingredients doesn’t happen, and its rich ingredients of fresh leaves are remains largely in processed green tea.
In this article, green tea means the tea with same processing of leaves such as sencha, deep-steamed sencha, kabusecha and gyokuro.
Let’s see what’s contained in your cup of green tea!
Green tea ingredients
As I talked, rich ingredients of fresh tea leaves are remains also in green tea leaves.
However, you need to eat whole tea leaves to take all the nutrition in, because some of them are not soluble in water.
(I guess many of you have never try to eat used up tea leaves, but there is a way to eat them deliciously. We will introduce the recipes in another article, look forward to it!)
Amino acids are the ingredients that consist umami of the tea.
There are some kinds such as theanine, glutamic acid, aspartic acid, arginine, serine etc… in particular, theanine occupies about 50% of total amino acid, and is typical ingredients of green tea.
Tea leaves create catechin by resolving theanine when they take the sunlight. The reason why gyokuro and kabusecha are covered before harvest is to maximize the amount of theanine in the leaves.
Amino acids extracts even in low temperature, so cold brew tea also contains amino acids.
Catechin is a one of polyphenols and also called as tannin. This is a typical ingredients of tea, the astringency taste is coming from catechin.
As I talked, gyokuro & kabusecha has more amino acids, means less catechin. The astringency is sometimes weaker than normal green tea.
Caffeine consist the bitterness taste of the tea. This amount is invariable during the processing of black tea leaves, therefore, the amount of caffeine is same before and after processing.
Actually, caffeine is contained about 3% of the weight of the tea leaves, this number is 2~3 times larger than the same amount of coffee beans. However, the amount of caffeine contained in a cup of tea is much smaller than coffee, because the amount of tea leaves(or coffee beans) per cup is different and caffeine is much easier to be extracted from crushing coffee beans.
Caffeine extracted well with 70~80℃ water. Therefore the green tea brewed with low temperature(50~60℃) has less caffeine than the one brewed with high temperature(70~80℃).
Saponin is also an ingredients that consist the bitterness of the tea, but the amount is quite small. Because saponin has a property as a surfactant, it causes tea to foam.
The amount is too small to expect its health benefit, but it is a constitution of bitter taste of the tea.
Actually, there are few aroma components contains in tea leaves before processing.
Through the crumpling process(one of the processings steps of tea leaves), the cell walls of tea leaves are destroyed, and the oxidation is intensified, flower-like or fluit-like aroma component is formed. However, green tea doesn’t contain many aroma components because there are no oxidation process.
About 200 types of components exist in green tea, and more than 600 types exist in black tea and oolong tea.
Green tea aroma is consisted from numerous aroma components such as linalool(lemon-like scent), dimethyl sulfide(seaweed-like scent).
High quality green tea such as gyokuro, kabusecha and also well-made sencha have a same scent called “Ooika”(means “covered scent” because this is scent created while the leaves are covered from sunlight before harvest) it is like a scent of seaweed. Dimethyl sulfide consists this scent.
Actually, dimethyl sulfide alone has stinky scent, but there is quite small amount contained in leaves and also the scent of dimethyl sulfide feel like seaweed-like scent when it is mixed with many other aroma components.
The scent of dimethyl sulfide gradually weakened soon after the leaves are proceeded, so you can feel the scent strongly from the fresh leaves or the leaves soon after you opened it.
Dimethyl sulfide is made from amino acids, so the tea leaves with strong “Ooika” means they have rich amino acids in it. As I talked before, amino acids are the components of umami, so “Ooika” is also the sign of rich umami and high quality.
Green tea leaves contain a lot of vitamin A,C,E,B,β-carotene(precursor of vitamin A) and so on.
You can take vitamin B and C from tea itself because they are soluble in water, but others are soluble in fat. Therefore, you need to eat leaves itself to take all vitamins in.
Chlorophyll is contained in green tea leaves. Since chlorophyll is essential ingredients for photosynthesis, the amount of chlorophyll increase under the situation of less sunlight. Due to this feature, gyokuro and kabusecha have a lot of chlorophyll in it.
However chlorophyll is not soluble in water, you need to eat tea leaves to take them in.
Many ingredients are contained in green tea leaves
Like this, the taste, aroma and color is consisted from many ingredients. The type and quantity differ depends on the types of tea and the processing method, it causes the difference of each green tea.