Don’t be surprised if the world-renowned Darjeeling tea, known for its characteristic aroma and therapeutic uses, is grown in and around Kolkata, or just about anywhere, in the future.
The generations old mysticism and romanticism of the aroma of Darjeeling tea has been shattered by Swati
Sen Mandi, a Kolkata-based scientist of Bose Institute, who has found that the incomparable muscatel flavour can be induced in any tea with the right doses of ultra-violet rays.
Following the 2010 finding, officials of Ging Tea Estate in Darjeeling have recently approached her for commercialisation of this method. However, the department of biotechnology did not evince interest in trying to turn the remarkable finding into a viable commercial process.
Mandi received a patent from the Kenya Industrial Property Institute in June 2010. The findings have also been published in two international journals – International Journal of Environmental Biology published from the US and African Journal of Biochemistry Research.
“The aroma and anti-oxidant level of Darjeeling tea, which makes it popular all over the world, is just because the leaves are exposed to an optimum level UV rays in the months of February to June, the season when the best tea leaves are plucked,” said Mandi senior professor of Bose Institute and emeritus medical scientist of ICMR.
Incidentally, in tea trade parlance, these teas are called first and second flush, with first flush tea commanding premium prices in all markets.
The question before Mandi was simple. Both Assam tea and Darjeeling tea contain the same genes and grow in similar soil conditions. What then causes the difference? Why Darjeeling tea had a typical aroma and high anti oxidant levels, while Assam tea failed to produce it? The answer could lie in the altitude, as Darjeeling tea grows at an altitude of nearly 4,500 feet and Assam tea grows at an altitude of 350 feet.
Mandi collected samples of both Darjeeling tea and Assam tea and carried on a series of tests in the laboratory of the Bose Institute. She found UV rays had something to do with the aroma and anti-oxidant level of Darjeeling tea.
She then performed some field trials in a tea garden inside IIT Kharagpur with samples of Assam tea. Mandi found that when Assam tea was exposed to optimum level of UV rays, the aroma and anti-oxidant levels increased.
The entire project was undertaken by the Bose Institute and funded by the department of biotechnology.
The amount of UV rays from the sun rises with altitude and between 15 degrees – 35 degrees North latitude. This is the reason due to which Assam tea, which is grown in much lesser heights or tea grown in Nilgiris, which is grown in other latitudes, do not produce the same aroma and antioxidants as that of Darjeeling tea.
Mandi said all plants contain an anti-oxidant compound called ‘flavonoids’. The higher the amount of flavonoid, the greater is the anti-oxidant level and greater the therapeutic use. Flavonoids combine with another compound, in the presence of certain enzymes to produce the characteristic aroma. The stronger the combination, the more would be the aroma. The entire process is enhanced by optimum amount of UV rays.
“In my paper I showed that if any species of tea plant is exposed to optimum levels of UV Rays the amount of flavonoids in it increases. In the long run these flavonoids would bring the aroma,” she said.
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