Green tea extract

Green tea is a type of tea that is made from Camellia sinensis leaves and buds that have not undergone the same withering and oxidation process used to make oolong teas and black teas. Green tea originated in China, but its production and manufacture has spread to many other countries in Asia. Green tea is a type of tea that is made from Camellia sinensis leaves and buds that have not undergone the same withering and oxidation process used to make oolong teas and black teas. Green tea originated in China, but its production and manufacture has spread to many other countries in Asia. Several varieties of green tea exist, which differ substantially based on the variety of C. sinensis used, growing conditions, horticultural methods, production processing, and time of harvest. Although there has been considerable research on the possible health effects of consuming green tea regularly, there is little evidence that drinking green tea has any effects on health. Tea consumption has its legendary origins in China during the reign of Emperor Shennong. A book written by Lu Yu in 618-907 AD (Tang dynasty), 'The Classic of Tea' (simplified Chinese: 茶经; traditional Chinese: 茶經; pinyin: chájīng), is considered important in green tea history. The Kissa Yojoki (喫茶養生記 Book of Tea), written by Zen priest Eisai in 1211, describes how drinking green tea may affect five vital organs, the shapes of tea plants, flowers and leaves, and how to grow and process tea leaves. Steeping, or brewing, is the process of making tea from leaves and hot water, generally using 2 grams (0.071 oz) of tea per 100 millilitres (3.5 imp fl oz; 3.4 US fl oz) of water (H2O) or about 1 teaspoon of green tea per 150 ml cup. Steeping temperatures range from 61 °C (142 °F) to 87 °C (189 °F) and steeping times from 30 seconds to three minutes. Generally, lower-quality green teas are steeped hotter and longer while higher-quality teas are steeped cooler and shorter, but usually multiple times (2-3 typically). Higher-quality teas like gyokuro use more tea leaves and are steeped multiple times for short durations. Steeping too hot or too long results in the release of excessive amounts of tannins, leading to a bitter, astringent brew, regardless of initial quality. The brew's taste is also affected by the steeping technique; two important ones are to warm the steeping container beforehand to prevent the tea from immediately cooling down, and to leave the tea leaf in the pot and gradually add more hot water during consumption. Polyphenols found in green tea include epigallocatechin gallate (EGCG), epicatechin gallate, epicatechins and flavanols, which are under laboratory research for their potential effects in vivo. Other components include three kinds of flavonoids, known as kaempferol, quercetin, and myricetin. Although the mean content of flavonoids and catechins in a cup of green tea is higher than that in the same volume of other food and drink items that are traditionally considered to promote health, flavonoids and catechins have no proven biological effect in humans. Consumption of green tea extract is linked to hepatotoxicity and liver failure. Green tea leaves are initially processed by soaking in an alcohol solution, which may be further concentrated to various levels; byproducts of the process are also packaged and used. Extracts are sold over the counter in liquid, powder, capsule, and tablet forms, and may contain up to 17.4% of their total weight in caffeine, though decaffeinated versions are also available.