‘Fermentation’ actually begins during rolling when endogenous enzymes are freed to comingle with other leaf components, primarily flavanols. ‘Fermentation’: During ‘fermentation’, tea undergoes significant compositional changes leading to the characteristic colour and flavour of black tea ( Sanderson, 1972). Other types of maceration equipment are now becoming popular, for example, crush, tear, curl (CTC) is gradually replacing orthodox processing in some growing regions ( Graham, 1983). Orthodox rolling involves use of traditional devices that impart a characteristic curl to the leaf. Rolling: The leaves are crushed and macerated, partially destroying cell structure, to allow enzymic oxidation of the flavanols in the presence of oxygen from the atmosphere. Chemical changes, including an increase in caffeine content, begin during this step ( Cloughley, 1983). A uniform moisture distribution is dependent on the uniformity of the flush and is important in maintaining the quality of the finished tea. Warm or ambient air may be circulated through the beds of tea leaves depending on local climatic conditions. Withering: After transport to the tea factory, freshly harvested leaves are spread in layers on trays and belts for up to 18 h in order to reduce the initial moisture content to approximately 60% of the leaf weight ( Graham, 1983). Mechanical harvesting is practised to some extent however, uniformity and, therefore, quality are considered to be superior with the precise selection of leaf that is achievable only by hand selection ( Graham, 1984 Forrest, 1985). Throughout many of the world’s tea growing regions, harvesting is done by hand as it has been for centuries. Flush is used for the manufacture of finished tea ( Graham, 1984). The bushes are usually kept about 1 m tall by pruning and periodic harvesting of new growth, called flush. The plant is a tender evergreen that can grow to heights of 12–14 m ( Forrest, 1985). Kuntze ( Cloughley, 1983), formerly called Thea sinensis ( Graham, 1984). Major exporting countries include Argentina, China, India, Kenya and Sri Lanka ( Forrest, 1985).Īll varieties and cultivars of tea belong to a single species, Camellia sinensis (L.) O. Tea is now grown commercially in tropical and subtropical regions of Asia, Africa and South America. With the opening of ocean routes to the east by European traders during the fifteenth, sixteenth and seventeenth centuries, commercial cultivation gradually expanded to Indonesia and then to the Indian subcontinent, including Sri Lanka. Tea was first cultivated in China and then in Japan. Black and green teas lightly flavoured with other botanicals are sometimes seen these include jasmine tea, scented with jasmine blossoms, and Earl Grey tea, flavoured with bergamot, a type of citrus fruit ( Graham, 1984). Oolong tea, found in some regions of China, is an intermediate variant between black and green tea ( Graham, 1983). Green tea is consumed mostly in Japan, China, North Africa and the Middle East the remainder of the world uses black tea. Today, tea is arguably the most popular beverage in the world ( Graham, 1984).īlack and green tea are the two main types, defined by their respective manufacturing techniques. The beverage’s popularity grew, and its trade became an economic mainstay. The first public sale of tea in England was held in 1657. Tea achieved popularity in the west only during the late seventeenth and eighteenth centuries, although it was brought to Europe in 1559 ( Wickremasinghe, 1978). The first generally accepted reference to tea is found in a Chinese dictionary from 350 AD which stated that the beverage was used as a medicine for various ills ( Schapira et al., 1975). The origin of tea is lost in ancient history, although legend dates it at about 2700 BC ( Woodward, 1980).
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