Chemical Properties
A shrub native to Ethiopia and now cultivated in tropical and equatorial regions. It can grow 10 m (33 ft) tall, but is
pruned to 4 to 5 m (13 to 16 ft) when cultivated. The branches are long with persistent leaves and white flowers. The ovary develops
into an ovoidal berry. The berry turns red as it ripens and contains two seeds (beans). The raw beans are gray or yellow in color; the
exact color depends on the quality of the bean. When roasted, the beans darken. Coffee has a distinct aroma and bitter taste.
Occurrence
Coffee is found in Central and South America.
Uses
Coffee is used to increase alertness, mood, exercise tolerance, and to enhance bronchodilation. Historically, coffee was administered by mouth for asthma, headache, and colds, or by rectum as an antidote for opium poisoning. It is used in herbal medicine to stimulate the appetite and facilitate digestion. Coffee promotes peristalsis and accelerates circulation (Felter, 1922). It may prevent onset of Parkinson's disease and gallstones (Jellin et al, 2008).
Composition
Roasted coffee beans are known to contain over 1,000 compounds identified as volatile flavor components.
These volatiles include pyrazines, aldehydes, furans, acids and thiols. Pyrazines (2-methoxy-3-isopropyl pyrazine, 2-methoxy-
3-isobutyl pyrazine, etc.) contribute as much as 14% of volatiles in roasted coffee. Three furanones also contribute to the
aroma/flavor characteristic of roasted coffee, which include 4,5-dimethyl-3-hydroxy-2(5H)-furanone, 5-ethyl-4-methyl-3-hydroxy-
2(5H)-furanone and 2,5-dimethyl-4-hydroxy-3(2H)-furanone. Constituents present in the oil of the bean include furfural,
sulfur derivatives and volatile acids. The stimulation effect of coffee is due to the presence of alkaloids (caffeine, adenine,
guanine, xanthine, etc.).
