Tea is the most consumed beverage in the world. It comes from an evergreen called Camellia sinensis. The health benefits of “tea” is generally appreciated but what is not known to many is how to maximize those benefits. It’s all about the degree of oxidation.
“Green” tea merely refers to the natural state of the Tea Plant; in the United States, the preferred tea is “black” tea. Black tea is green tea that is partially oxidized. While this has certain flavor advantages, much of the health benefits of green tea is lost. So-called white tea is just young green tea and does not have the phytonutrients density as the mature green tea.
Whenever the tea leaf is fragmented, there is a disruption of cellular contents. The cellular contents of tea with sought-after health benefits are a class of compounds called polyphenols, particularly catechins. These are present in the cell’s vacuoles; when they come into contact with the polyphenol oxidase in the cell’s cytoplasm, after cellular disruption, the polyphenol is deactivated.
When tea leaves come into contact with water, particularly at higher temperatures, cell walls are partially disrupted and soluble cellular contents enter solution. Entrained and solubilized oxygen then can oxidize the polyphenols catalyzed by the enzyme polyphenol oxidase and health benefits are reduced.
But we can do something to minimize that regrettable situation.
Effect of acidity
The optimum pH for polyphenol oxidase activity varies but is around 7. However, the enzyme activity rapidly decreases at more acidic pH values as provided by citrus fruits such as lemons or limes .
It has been shown that complete inhibition of polyphenol oxidase activity is found with an ascorbic acid solution .
Citric acid also can inhibit activity, although not as strongly as ascorbic acid . Citric acid exists in much greater than trace amounts in a variety of fruits and vegetables, most notably citrus fruits. Lemons and limes have particularly high concentrations of the acid; it can constitute as much as 8% of the dry weight of these fruits.
How do you take your tea?
Mention should be made of the best way to consume any plant is by eating it, not just consuming that which solubilizes in water. Bulk green tea leaves are quite inexpensive (see an example here) and can be, for example, be added to green smoothies for optimum nutrition. The same oxidative penalties may arise though – see a study I wrote on reducing that problem here.
Here’s how to make a better cup of hot tea
Boil water. Remove from heating source and add the juice from a fresh lemon or lime. Then add tea bag or infuser or raw green tea leaves. Do this for each individual cup of tea – do not store.