Green Tea Ingredients
Chemical Composition and Constituents
The most important green tea ingredients are catechins, theanine and caffeine. A guide to green tea chemical composition and constituents.
Green
tea ingredients are extremely complex. It contains as many as 200 bioactive
compounds.
Not only are they complex, being plant material, their levels also extreme variable and change with location, harvesting season and making process.
The largest and most important
chemical compound is polyphenols. Why are polyphenols so important? This is because they contain flavonoids - an
important class of antioxidants.
But high levels of polyphenols make bad green tea. This is because they are
astringent (a dry mouth feeling) tasting. Therefore Chinese and Japanese green tea plants tend to have lower level of
polyphenols than black tea plants.
Green tea drinkers are compensated by the presence of another delicious
compound: theanine, which I will explain later. The best green tea is harvested in spring when the theanine to polyphenol
ratio is the highest.
According to scientist Graham Harold, dried tea extract can contain 30% to
40% of catechins. The four main catechins are:
- Epigallocatechin-3-gallate (also known as EGCG)
The star of the show, of course, is EGCG. Found in the highest
concentration in green tea, it is the most active and best researched of all green
tea ingredients.
Put it simply, it explains most of green tea health benefits.
It has been found to be over 100 times more effective in neutralizing free
radicals than vitamin C and 25 times more powerful than vitamin E.
It also tops other antioxidants, such as butylated hydroxyanisole (BHA),
butylated hydroxytoluene (BHT) and resveratol.
Dried leaves can contain 7% to 14% of other
flavonoids compounds.
About two thirds of these flavonoids are flavonols. Also powerful antioxidants, they are
known to be anti-histamine and anti-inflammatory.
Dry green tea contains 2% to 3% of theogallin, which is unique only to tea. It
also contains depsides such as chlorogenic acid and coumarylquinic acid.
Dried tea extract contains 4% to 6% of theanine, an amino acid found only in tea. It is what gives tea the characteristics flavour. Catechins and caffeine taste
bitter and astringent, but theanine tastes sweet and fresh.
Catechins have been drumming their benefits in recent years. But it is for theanine that tea lovers have yearned for centuries.
Feel caffeined out? Lacking some sleep? Feeling stress? Theanine stimulates
alpha brain waves, calms the body and promotes relaxed awareness. It is the interplay between catechins, theanine and caffeine that makes green
tea such a fascinating beverage.
Theanine - 10 Astonishing Facts To Know
Caffeine is a plant alkaloid found in coffee, tea and cocoa. It acts as
natural pesticide, protecting plants against certain insects feeding on them.
Green tea contains alkaloids known as methylxanthines such as caffeine,
theobromine and theophylline.
Graham found that fresh leaves contain, on average, 3% to 4% of caffeine and
very small amounts of the other methylxanthines.
Are you ready to explode the myths about caffeine?
Green Tea Caffeine
Green tea contains several B vitamins and C vitamin. Being less processed
than black tea, these vitamins are left intact in the tea-making process.
Other green tea ingredients include 6% to 8% of minerals such as aluminium,
fluoride and manganese.
Green tea also contains organic acids such as gallic and quinic acids,
and 10% to 15% of carbohydrate and small amount of volatiles.
Harold N, Graham PD (1992). Green tea composition, consumption and polyphenol
chemistry. Journal of preventive medicine and hygiene. 1992
May;21(3):334-50.
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