Green Tea Modern Benefit,Applicable Uses and Research New findings.Green Tea Extract.Green Tea Polyphenols.

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Brief Introduction of Tea Bioactive Compounds.

Green Tea Extract INCI Name Camelia Sinensis Extract EINECS ELINCS No 283-519-7 CAS 84650-60-2 Tea Polyphenols photo picture image Chemical analysis has revealed that green tea contains significant amounts of water-soluble vitamins and minerals, particularly zinc, manganese, potassium, niacin, folic acid and vitamin C. In fact, one cup of green tea has more vitamin C than an orange. Researchers at the University of Kansas attributed green tea with 100 times the antioxidant strength of vitamin C, and 25 times that of vitamin E. A United States Department of Agriculture study found that the antioxidant capacity of green tea is better than twenty-two various fruits and vegetables.

 1.Flavonoids:

 Flavanols are the most abundant class of flavonoids in tea. Flavanol monomers are also known as catechins. The principal catechins found in tea are epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG). When catechins are enzymatically oxidized by polyphenol oxidase during fermentation, they form Polymers known as theaflavins and thearubigins. Unfermented teas are rich in catechins, while fermented teas are rich in theaflavins and thearubigins (see Types of Tea above). Tea is also a good source of another class of flavonoids, called flavonols. Flavonols found in tea include kaempferol, quercetin, and myricitin. The flavonol content of tea is less affected by processing, and flavonols are present in comparable quantities in fermented and unfermented teas. Unlike flavanols, flavonols are usually present in tea as glycosides (bound to a sugar molecule).

 2.Caffeine:

 All teas contain caffeine, unless they are deliberately decaffeinated during processing. The caffeine content of different varieties of tea may vary considerably and is influenced by factors like brewing time, the amount of tea and water used for brewing, and whether the tea is loose or in teabags. In general, a mug of tea contains about half as much caffeine as a mug of coffee. The caffeine contents of more than 20 green and black teas prepared according to package directions are presented in the table below. The caffeine content of oolong teas is comparable to green teas. There is little information on the caffeine content of white teas, since they are often grouped together with green teas. Buds and young tea leaves have been found to contain higher levels of caffeine than older leaves, suggesting that the caffeine content of some white teas may be slightly higher than that of green teas.

Caffeine Content of Teas and Coffee
Type of Tea Caffeine (mg/liter) Caffeine (mg/8 ounces)
Green 40-211 9-50
Black 177-303 42-72
Coffee, brewed 306-553 72-130

 3.Fluoride:

 Tea plants accumulate fluoride in their leaves. In general, the oldest tea leaves contain the most fluoride. Most high quality teas are made from the bud or the first four leaves-the youngest leaves on the plant. Brick tea, a lower quality tea, is made from the oldest tea leaves, and is often very high in fluoride. Symptoms of fluoride excess (dental and skeletal fluorosis) have been observed in Tibetan children and adults who consume large amounts of brick tea. Unlike brick tea, fluoride levels in green, oolong and black teas are generally comparable to those recommended for the prevention of dental caries (cavities). Thus, daily consumption of up to one liter of green, oolong, or black tea would be unlikely to result in fluoride intakes higher than those recommended for dental health. The fluoride content of white tea is likely to be less than other teas, since white teas are made from the buds and youngest leaves of the tea plant. The fluoride contents of 17 brands of green, oolong, and black tea are presented in the table below . These values do not include the fluoride content of the water used to make the tea.

Fluoride Content of Teas
Type of TeaFluoride (mg/liter)Fluoride (mg/8 ounces)
Green1.2-1.70.3-0.4
Oolong0.6-1.00.1-0.2
Black1.0-1.90.2-0.5
Brick tea2.2-7.30.5-1.7

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citations1.Green Tea Modern Benefit,Applicable Uses and Research New findings.Green Tea Extract.Green Tea Polyphenols.

last edit date:8th,May.2009.