Tea contains small amounts of theobromine and slightly higher levels of theophylline than coffee. Certain types of tea, such as black and oolong, contain somewhat more caffeine than most other teas. Tea usually contains about half as much caffeine per serving as coffee, depending on the strength of the brew. Tea is another common source of caffeine. Coffee also contains trace amounts of theophylline, but no theobromine. Arabica coffee normally contains less caffeine than the robusta variety. Generally, dark-roast coffee has less caffeine than lighter roasts because the roasting process reduces the bean's caffeine content. In general one serving of coffee ranges from about 40 milligrams for a single shot (30 milliliters) of arabica-variety espresso to about 100 milligrams for strong drip coffee. Caffeine content in coffee varies widely depending on the type of coffee bean and the method of preparation used even beans within a given bush can show variations in concentration. The world's primary source of caffeine is the coffee bean (the seed of the coffee plant), from which coffee is brewed.
Two of caffeine's alternative names, mateine and guaranine, are derived from the names of these plants. Other, less commonly used, sources of caffeine include the yerba mate and guaraná plants, which are sometimes used in the preparation of teas and energy drinks. The most commonly used caffeine-containing plants are coffee, tea, and to some extent cocoa. May be fatal if inhaled, swallowed or absorbed through the skin.Ĭaffeine is a plant alkaloid, found in numerous plant species, where it acts as a natural pesticide that paralyzes and kills certain insects feeding upon them. Chemical and Physical Properties of Caffeine Many natural sources of caffeine also contain widely varying mixtures of other xanthine alkaloids, including the cardiac stimulants theophylline and theobromine and other substances such as polyphenols which can form insoluble complexes with caffeine. In North America, 90% of adults consume caffeine daily.
Beverages containing caffeine, such as coffee, tea, soft drinks and energy drinks enjoy great popularity: caffeine is the world's most widely consumed psychoactive substance. Caffeine is a central nervous system (CNS) stimulant, having the effect of temporarily warding off drowsiness and restoring alertness. Overall, caffeine is found in the beans, leaves, and fruit of over 60 plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding upon them. It is found in the leaves and beans of the coffee plant, in tea, yerba mate, and guarana berries, and in small quantities in cocoa, the kola nut and the Yaupon Holly. Caffeine is sometimes called guaranine when found in guarana, mateine when found in mate, and theine when found in tea. Caffeine is a xanthine alkaloid compound that acts as a stimulant in humans.
Caffeine Molecule C 8H 10N 4O 2 What is in coffee?
0 kommentar(er)
