Types of tea

Everyday my parents make a cup of tea in morning and afternoon. They drink it everyday. We drink a black tea here. My parents like to  add sugar in it. There are many types of tea and every country has a different tradition when it comes to drinking tea.

Black tea is consumed principally in Europe, North America and North Africa (except Morocco) while green tea is drunk throughout Asia; oolong tea is popular in China and Taiwan.

All tea is produced from the leaves of the tropical evergreen C.Sinensis. There are three main types of tea with black tea made via a post-harvest “fermentation,” an autoxidation catalyzed by polyphenol oxidase. After picking, leaves for green tea are steamed to inactivate polyphenol oxidase prior to drying. Oxidization is a chemical reaction that takes place when tea leaves are picked and begin to wither and die.

White tea doesn’t oxidation. They also have the lowest amount of caffeine and most likely have the highest antioxidant properties.

Green tea is not allowed to oxidize and is quickly dried, pan fried or oven fired to dehydrate the tea leaves for storage.  This process retains many  of the polyphenols, catechins, and flavonoids that are associated with the health benefits of drinking green tea.

Oolong tea is produced by a partial oxidation of the leaf, intermediate between the process for green and black tea. Oolong tea falls somewhere between green tea and black tea in the amount of time the tea leaves are allowed to oxidize.  Two terms often used to describe oolong tea are “green” and “amber” style.  The “amber” styles are allowed to oxidize slightly more than the “green style” oolong tea.  This results in a variety of smooth teas available that bear the makers style and tradition. Oolong tea commonly served in Chinese restaurants or sold as “weight loss tea” due to its high caffeine content which encourages fat metabolism. Each cup has around 10-15% of the caffeine in cup of coffee. Oolong tea can be processed in two main ways, either as long curly leaves or rolled into tight balls similar to gunpowder tea, sometimes called dragon pearl tea.

Approximately 76% to 78% of the tea produced and consumed worldwide is black, 20% and 22% is green and less than 2% is oolong.

Tea is an important dietary source of flavanols.  Tea consumption has been inversely associated with the development and progression of atherosclerosis. Elevated blood pressure can accelerate the atherosclerotic process, and evidence linking reduced blood pressure with tea consumption has been reported in studies of green tea polyphenols in hypertensive animals and among black tea drinkers in Norway . Habitual moderate strength green or oolong tea consumption, 120 mL/d or more for 1 year, significantly reduces the risk of developing hypertension in the Chinese population.

Evidence for the anticarcinogenic potential of tea polyphenols has been provided by  numerous in vitro and experimental studies describing their action to bind directly to carcinogens, induce Phase II enzymes such as UDP-glucuronosyl transferase and inhibit heterocyclic amine formation.

Tea is already one of the most popular beverages worldwide and there are many benefits for our  body. So do you want to drink a glass of tea?


References

McKay, Diane L,. et al. 2002. The Role of Tea in Human Health: An Update. USA.  Journal of the American College of Nutrition, Vol. 21, No. 1, 1–13

Yang, Yi-Ching MD, MPH., et al. 2004. The Protective Effect of Habitual Tea Consumption on Hypertension. ARCH INTERN MED/VOL 164