Tea is the most commonly used soft beverage in the household. It acts as a stimulant for central nervous system and skeletal muscles.It removes fatigue n headache.It is also used for lowering the body temperature. The principal constituent of tea, which is responsible for all these properties,is the alkaloid-caffeine.
It was thought that caffeine is responsible for the taste n flavour of the tea. But pure caffeine is found to be a tasteless substance. So the taste of the tea is due to some other substance present in it.
Purely it is white, crystalline solid in the form of needles.melting point is 1230c. It is the main active principle component of tea leaves. It is present in tea leaves up to 3% and can be extracted by first boiling the
tea leaves with water which dissolves many glycoside compounds in addition to
caffeine. The clear solution is then treated with lead acetate to precipitate the
glycoside compounds in the form of lead complex. The clear filtrate is then extracted with extracts caffeine because it is more soluble in it then water.
Its been experimentally proved tat in 50gms of tea there is 0.60gms (approximately) of caffeine is present. For this reason tea should be excluded from our diet.
