Tea

Tea is a drink, which is made by infusion of the leaves of the tea bushes.
Very refreshing because of the content of caffeine, essential oils and tannins (tea tannin).
Caffeine content in tea ranging from 1.2 to 3%, a significant part of it is in connection with tannins. Essential oil of tea, which are contained in a very small number (about 0,006%), add fragrance to drink and have a stimulating effect on the body, complementing the effects of caffeine. Tannins - tannins (8 - 15%) - define the taste, color, tartness of tea, the majority of them has a P-vitamin activity and antimicrobial activity. In tea contains organic acids (mainly oxalic and citric), having a value in education taste bouquet. The basic parameters of quality of tea, and research methods specified in a special Guest (№ 1936-64).

Tea is rich in fluorine (75-100 parts per 1 million parts of dry matter). Its content depends on the ability to absorb fluorine from the soil by plants (tea tree), from fertilizers, from the age of tea leaf, time of collection and the geography of tea. The amount of fluoride in the ready drink depends on its fortress, the duration of infusion and other Boiling so-called essence leads to increased content of fluorine and the change of taste. The best taste and aroma possesses tea, nastaivalsya 5 min; in 1 glass contains about 0.2 mg of fluoride. In the UK, where they drink tea all residents regardless of age, the child only from the tea gets 1,26 mg of fluorine per day, and an adult is 2.33 mg In Iran consumption of this drink is the highest in the world - 48000 tons per year (here drink it more than in England)in Poland - about 21,000 tons per year.
In such teas, as Assamese, Darjeeling, Ceylon and other, 100 g of dry leaf contains from 10.25 until 15,25 mg of fluoride. Chinese teas can be from 3 to 400 ppm, as the Chinese use to spray tea Bush fluorine-containing pesticides. Milk is usually to 0.17 ppm of fluoride, but if the cows drink water, in which, for example, contained 8 ppm of fluoride, the amount of this element in milk is increased to 0.3 ppm. So with tea also need to be careful! Perhaps, from this point of view, do not drink too strong tea.

Tea - leaves of the tea plant, processed industrially. The infusion of tea in hot water, bearing the same name, is widely used by many people as a tasty drink belongs to the group of drinks containing alkaloids. The main types of tea: tea (black and green), brick, tiled; more common tea black tea. The most important constituent of tea: tannin (tea tannin, caffeine, extractive substances (see table).

The most important part of the different kinds of tea
The objects of research Constituent of tea (in % to dry. substances)
tannin caffeine extractive substances
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Kind of tea:
green
yellow
red
black
brick (from old calloused leaves)
25,0

24,5
21,7
17,5
14,7
10,0
2,35

2,30
2,30
2,35
2,35
1,20
44,3

45,4
43,1
40,3
38,2
28,5

During processing of the tea leaves most parts undergoes biological transformation, which essentially determines the quality of tea (color of the drink, flavor and taste) as the product of industrial manufacturing.
Tannin tea represent a mixture of different organic compounds; most of them belong to the catechins (see) and their derivatives. The latter has a high P-vitamin activity (see Vitamin P). A significant part of tannins is lost when fermentation, representing an important process in the technology of production of black tea. In this regard, in green tea (not fermented) tannins more than black and P-vitamin activity it almost 1.5 times higher. Tannins have antimicrobial properties.
Caffeine (see) - the most important part of tea, he drink owes its tonic effect on the body. The amount of caffeine in tea varies from Botanical varieties of raw materials and types of tea from 2-3% to 5% (dry substance); especially its a lot of young leaves of a Bush. In the higher grades of Georgian tea quantity reaches 3% of the stock, and in the lower 1,96-1,71%.
The essential oils contained in tea, add fragrance to drink. Tea also contains vitamin C, thiamine and Niacin. A significant part of vitamin C in the fermentation process sheet collapses: green leave it - 226 mg%, and the black tea remains to 17.4 mg%; thiamine black tea - 94,4 mcg%; nicotinic acid black tea - 15 240 mcg%in the green - 10 260 mcg%. Ash tea - its about 5% - contains potassium (40%), calcium (4,24%), magnesium (6,47%), phosphorus and other