Caffeine is permitted in the USA in nonalcoholic carbonated cola-type beverages at a content of up to 0.02% by weight of the finished product ( Anon., 1987b US Food and Drug Administration, 1988). In the Federal Republic of Germany, approximately 500 tonnes of caffeine are obtained annually from the decaffeination of coffee, while some 3000–3300 tonnes are produced synthetically ( Menthe, 1985).Īpproximately 80–90% of caffeine extracted from green coffee is used in the beverage industry and most of the remainder and synthetic caffeine are used in pharmaceutical applications ( Anon., 1987a, 1988). It is estimated that 60% of caffeine used in the USA is synthetic ( Anon., 1986).Ĭaffeine is also produced in China, the Federal Republic of Germany, Italy, Japan, the Netherlands and Switzerland ( Anon., 1987a, 1988, 1989a Stabilimento Farmaceutico ‘Cau. US synthetic production capacity was reported to have been expanded in 1989 by an additional 500 000 pounds (227 000 kg) ( Anon., 1989a). Caffeine is produced from green coffee by two companies in the USA ( Anon., 1987a) and synthetic caffeine by one ( Anon., 1989a). Estimates for the amount of caffeine sold in the USA ranged from 8 to 12 million pounds (3632–5448 thousand kg) in 1986, 80% of which was used in soft drinks ( Anon., 1986). US imports of caffeine and its derivatives totalled 6.9 million pounds (3133 thousand kg) in 1987 ( Anon., 1988), 5.3 million pounds (2406 thousand kg) in 1986, 5 million pounds (2270 thousand kg) in 1985 ( Anon., 1987a) and 6.2 million pounds (2815 thousand kg) in 1980 ( Hirsh, 1984). US imports of caffeine in 1988 totalled 6 345 310 pounds (2900 thousand kg), while exports during this period were 753 515 pounds (342.1 thousand kg) ( US Bureau of the Census, 1989). The US International Trade Commission did not report domestic production from green coffee beans or of synthetic caffeine for 1986 ( US International Trade Commission, 1987). Contemporary figures for the production of caffeine in the USA could not be obtained production in 1962 totalled 1 959 000 pounds (889 400 kg), while caffeine imports totalled 1 807 000 pounds (820 400 kg) ( Huber, 1964). Most of the caffeine produced in the USA prior to 1945 was obtained by methylation of theobromine extracted from cocoa the methylation agents used were dichloromethane and dimethyl sulfate. Synthetic production of caffeine involves the methylation of various xanthines (primarily theobromine) ( Halsey & Johnston, 1987) and theophylline ( Stanovnik et al., 1982 Nesterov et al., 1985) or the reaction of theophylline with carbon monoxide and methanol ( Bott, 1982) total synthesis can be achieved with dimethyl carbamide and malonic acid ( Anon., 1987b). The extraction yields in the production of natural caffeine have declined significantly in recent years, following the increasing use of water-based as opposed to direct solvent-based extraction procedures. Pressurized carbon dioxide is employed to remove caffeine from tea in the production of decaffeinated tea ( Anon., 1986). Refining processes are needed to provide the pure caffeine of commerce. Caffeine has been obtained as a by-product from the manufacture of caffeine-free coffee ( Budavari, 1989), initially by water and then by solvents, e.g., trichloroethylene (see IARC, 1979a, 1987), dichloromethane (see IARC, 1979b Anon., 1986 IARC, 1987), ethyl acetate ( Anon., 1986, 1987a), water-carbon dioxide processes ( Anon., 1987a), and also using oil from spent coffee grounds to remove caffeine from green coffee beans ( Anon., 1986). Extraction procedures involve three methods: direct decaffeination of green coffee beans with solvents, extraction from tea dusts and wastes and fragments of tea leaves, and extraction from cola nuts ( McCutheon, 1969 Menthe, 1985 Halsey & Johnston, 1987). Caffeine is produced commercially by both extraction and synthetic procedures.
0 Comments
Leave a Reply. |