Introduction
According to Chinese legend, in 2737 B.C., Chinese Emperor Shen Nung sat next to a small cauldron of boiling water. Suddenly, he smelled a wonderful smell and found that leaves from the flowering camellia tree, Camellia sinensis, had fallen in the water. He sipped the water and discovered tea, which more than 4,000 years later, is the world's second most popular drink. Over the past few decades, scientists have taken a closer look at the potential health benefits of tea. |
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What is Tea?
All tea comes from same plant — the Camellia Sinensis. How the leaves are processed and their levels of contact with oxygen determine the resulting types of tea and the polyphenol content. During oxidation, tea leaves undergo natural chemical reactions that result in distinctive color and taste characteristics. This oxidation process reduces the polyphenol content and other nutrients in the tea. |
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How is Green Tea Different?
Black tea undergoes a fermentation process, which oxidizes the leaves and turns them "black". This process deactivates many of the polyphenols, and creates a bitter taste. Oolong tea is oxidized about half as long (semi-fermented) and is then steamed to stop oxidation, and has bitter taste. Green tea is not fermented at all. It is steamed to stop oxidation before it starts, which preserves most of the polyphenols. Green tea contains 60% more polyphenol content than black tea, and has less bitter taste. |
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What are Polyphenols?
Polyphenols (flavonoids) are powerful antioxidants that are 100 times more potent than Vitamin C and 25 times more than Vitamin E. Polyphenols are important for fighting harmful free radicals, which cause degenerative diseases and immune system deficiency.
Studies show that consuming foods high in polyphenols can promote good health, maintain normal weight and stimulates the immune system. Green tea contains higher antioxidants—flavonoid polyphenols than black and oolong teas.
The polyphenols that exist in green tea are mainly (-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), (+)-epicatechin (EC), (-)-gallocatechin gallate (GCG), and (-)-catechin. EGCG is the most powerful and the most abundant of the six major catechins found in green tea. |
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