Although both green and black tea come from the camellia sinensis plant, the quantity and kinds of catechins found in green and black tea vary due to their different processing methods.
How are green and black tea processed?
When green tea is processed the leaves are immediately steamed after picking, this halts the oxidation of the leaves, which means a high concentration of catechins is retained in the leaves.
When black tea is processed the leaves are first withered. The leaves are dried in the open air or air is pumped through the layers of leaves. The leaves are left to oxidise for an extended period and this causes the leaves to change colour from green to coppery brown. During this process the catechins are converted to complex flavanoids known as theaflavins and thearubigins.
The processing of black tea produces the distinctive taste and aroma of black tea, but also means much of catechin content and goodness is destroyed.
What do the catechins in green tea do?
There are four catechins in green tea. The catechins found in green tea are epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), epicatechin gallate (ECg) and epigallocatechin gallate (EGCg) The most active and beneficial catechin in green tea is epigallocatechin gallate (EGCG).
A cup of green tea contains approximately 40-90mg of EGCg.
A cup of black tea contains approximately 5-10mg of EGCG.
Catechins work by neutralizing and inhibiting free radicals which destroy healthy cells and tissues in the body and contribute to aging and disease.
Conclusion
The catechins found in green and black tea differ due to their different processing methods. Green tea is an unfermented tea (not exposed to oxygen after picking) and is able to retain its high catechin content. While black tea is fully fermented (extensively oxidised), which means much of the beneficial catechin components are destroyed.
Although both green and black tea contain catechins, green tea has the higher catechin content of the two. To fully reap all the health benefits of green tea, it is suggested you should drink between 3-10 cups a day. I personally recommend brewing your own green tea leaves rather than using tea bags. The flavour and quality of the leaves is superior and also you can re-brew with the same leaves a few times over.
