Black Tea Dimeric and Oligomeric Pigments—Structures and Formation

Many of us consume tea daily, but it is surprizing how few know where it comes from or how it is made. Tea comes from the tea plant the botanical name for which is Camellia sinensis (L.) O. Kuntze.1 This is a white-flowered evergreen indigenous to the rainforests of Assam, Northwest Burma and South West China, but now cultivated in over 30 countries around the world in places as far apart as Argentina, China, Papua New Guinea, and Turkey. However, since most tea leaves are plucked by hand, the largest plantations are most often found in countries with low manual labor costs. Two main varieties of tea are cultivated; Camellia sinensis var sinensis and C. sinensis var assamica. There is some controversy as to whether these are varieties or two distinct species.1 C. sinensis var. sinensis L, is grown mainly in China and Japan; it is a slow-growing bush, has small narrow leaves and is used for green tea manufacture. The second variety Camellia sinensis var. assamica is grown primarily in India and Africa, is fast growing, has a treelike habit, large broad leaves, and is the source material for black tea. In its cultivated state, it is pruned to approximately 3 feet for ease of harvesting the young shoots (flush), from which the tea is manufactured. This process (plucking) is carried out every 7–14 days during the growing season.