Green Tea Project

By Jorge Wei

Discovery of Tea

Tea relates to chemistry because of all the reactions that happen while the tea plant is growing, once the leaves of the tea plant touch hot water, and again when that tea-water concoction enters your body. Being a plant, tea is a solid element, but we call it by the same name when the leaves from that plant are infused into a beverage, so tea is also a liquid.

Tea was brought into use as a drink around 2700 BC by the Chinese Emperor Shen Nong. Some say that Emperor Shen Nong discovered tea accidentally one day when he was outside and asked his servants for something to drink. They were boiling some water for him to drink when leaves from a tree were blown into the hot water, resulting in the Emperor's water turning a brownish colour, yielding a refreshing drink which the emperor enjoyed very much. In some accounts of the origin of Green Tea, the emperor is credited as being the creator of this magnificent drink still widely popular these many centuries later.

Green tea is a naturally occurring substance. All people need to make tea is hot water and either tea leaves or a tea bag. Small twigs and flower buds are also present in harvested tea. Steeping the leaves of tea in hot water creates the infusion beverage known to us as tea. Before tea was invented people drank wine or alcohol, but since tea was "discovered" it has been preferred it for its refreshing quality and delightful taste and health promoting benefits. At first, tea was imbibed only by the rich and powerful but as years passed it seemed that everyone who could acquire it, wished to drink tea.

Harvesting and Storing Green Tea

When tea was first made, fresh leaves were simply added to hot water. A multi-step process for curing tea leaves was invented early on, and is still in use today. The number and type of steps involved in curing tea leaves determines whether tea will be White [least processed], Green [minimally processed], Oolong [medium-processed] or Black [most processed]. First, the leaves get picked. During the initial harvesting period, oxygen enters the leaves' membranes, and clorophyll is released from them, both of which processes which make the tea leaves darker. This is referred to as the oxidation process, or fermentation.

Oxidization of green tea leaves is stopped early because the leaves won't stay green if they are left to dry on their own. In order to stop the oxidation process get pan fried in China for the characteristic mild flavour of Chinese green tea at about 100º C for just under an hour, or are steamed in Japan, within a maximum of two hours after the leaves are picked. Halting the oxidation process also preserves tea's polyphenol content. Green tea leaves will be rolled and dried after heating. While the leaves are being rolled their oil comes out of the leaves, giving the leaves their beautiful smell.

Tea is produced from the leaves of the Asian plant Camellia Sinensis, an evergreen bush which also produces white flowers. It grows best in soil with a slightly acid content of 5-5.6 pH. Tea can be associated with a leaf size, a region - such as Ceylon or Darjeeling, its final storage method such as Pekoe (cut) or gunpowder (rolled), as well as by the curing process which will determine tea's color. The major health benefits associated with tea are found most abundantly in green and oolong teas, and to a much lesser degree in black teas.

Antioxidant Benefits of Green Tea

Green tea is a very healthy drink for people to consume. It’s got tons of ingredients to keep people healthy and lively. Green tea is noted for having possibly the highest concentration of all tea products of the polyphenol catechins, which have a honeycomb chemical structure and are powerful antioxidants that neutralize free radical cells caused by oxidate stress. Free radical cells cause cancer, the breakdown of neurons needed by the brain to transmit signals throughout our bodies and other health issues.

Free radical cells are cells that due to oxidative stress have acquired an extra neuron which has no pair and is looking for one. These bad cells go around the body looking for other cells which can be enticed to yield up one of their elements to pair with the "free radical" element. A free radical cell often cause a cascade effect where cells that gave up a paired element in response to the free radical's need for a partner element to stabilize itself, themselves become unstable. And then go on to destabilize cells around them in the same way. Free radical cells stop being destructive when during the antioxidant process they acquire the extra element they need to pair with the free radical contained within them.

Green tea is best known popularly for its antioxidant properties. The powerful antioxidants found in green tea are attributed by some with the ability to heal cancerous free radicals to the extent that cancer can be reversed in early stages. Carrying out their antioxidant function, polyphenols transform damaging free radical cells into the whole, healthy, cells that a person’s body needs.

Green tea is also being studied for its apparent ability to inhibit MPTP which relieves symptoms of Parkinsons and to relieve Alzheimer's by coincidentally boosting production of the neurotransmitter acetylcholine (ACh) and inhibiting the production of cholinesterases (AChE) which breaks down that neurotransmitter. The principal polyphenol in green tea is (-)-epigalochatechin-3-gallate (EGCG). Green tea polyphenols are also referred to as (GTP) or green tea catechins (GTC).

Green tea can lower people's cholesterol and helps with diabetes by helping the body break down food and convert it into useful energy. It can protect the liver from getting damaged by the toxins in alcohol and can help people maintain heart health and lose weight with its main ingredient, the phytochemical catechin. The level of catechins found in green tea is higher than the levels in red wine and grape juice, and provide the same heart disease prevention protection. It also provides dental benefits by reducing oral bacteria plaque and periodontal disease, especially when used as a mouthwash, reduces gastrointestinal gas, has a beneficial effect on memory and can be used to heal wounds and control bleeding.

Other Health Benefits

Tea also contains L-theanine, a chemical substance which lowers anxiety. Perhaps this quality is what makes the sharing of tea drinking a pleasant activity in which to participate. It also happens to be a very healthful one. Many studies have linked the reduction of stress with improved health, and shared company is another way to reduce it.

Green tea has pH values ranging from 4 to 5.9. Its health benefits are thought to be most effective at lower pH values. We can compare these value with water, which has a pH of 7. pH above 7 is alkaline and below is acid. Several sources I reviewed put the optimal quantity of green tea at two cups a day and some sources warned that its effect may become toxic after 5 cups. From these statements I conclude that it may be best to vary green tea consumption with oolong.

The average cup of green tea contains from 50 to 150 mg polyphenols. A recent New Zealand study found that to produce the maximum yield of catechin polyphenols and EGCG, green and oolong teas must be steeped at as close to the boiling temperature as possible. When steeped in water temperatures of 100º C double the health elements are present in tea compared to when tea is steeped in water of 60-80º C.

My Thoughts on Tea

I think that tea is an excellent substance that’s been put to good use by people for thousands and thousands of years, and that the success of tea as a beverage which provides both sensory enjoyment and physical wellness, is largely due to its production being very little tampered with. As of 2005, 450 patents had been applied for worldwide on tea, or Camellia Sinensis. I personally don’t think people will find a way to make this natural product better than it already is. I don't think that anyone, or any entity, should be permitted to establish ownership of it, either. Tea is a product of our earth and it ought to belong to everyone. After Emperor Shen Nong first discovered the enjoyment of tea in 2700 BC, people soon learned how to harvest and preserve this wonderful leaf, and in the wisdom of ancient culture, they knew enough to leave it alone after that. Tea now, as it did 5000 years ago, tastes as good as it can taste and is as healthy for people as it can possibly be.


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