Tea Leaves Essay

482 Words2 Pages
Tea is made from the young leaves andbuds of the tea plant. Tea leaves are rich incaffeine (an alkaloid). Besides caffeine, tealeaves also contain tannic acid and coloringmatter, such as polyphenolic compounds. The relative amounts of these substances aredifferent in different varieties of tea leaves,which is why, their tastes and flavours aredifferent.The brownish color of the tea is due tothe presence of polyphenolic compounds andsome organic ions like Mn +2 , Fe +3 , etc. Somesimple experiments can be carried out tostudy the components that are responsiblefor the variation in tea flavour in variousbrands of tea. EXPERIMENT - I AIM: Compare the water soluble polyphenol (catechin)content in various samples of tea leaves. REQUIREMENTS: Beakers, conical flasks, funnels,heating arrangement, tea bags of different brands of tea. THEORY: Tea contains upto 30% of the water solublepolyphenols (catechin). These are largely responsiblefor the flavour of the tea. To estimate the extent of these compounds in a given sample, the tea leavesare immersed in hot water for equal time and the lossin weight of tea leaves is determined. PROCEDURE: 1. Weigh exactly 3 g of each of the differentsamples of tea and place them in tea bags.2.Take three or four conical flasks and put 100 mlof hot water into each of them. 3. Put tea bags of different samples of tea in thedifferent conical flasks. After 10 minutes, remove the tea bags and dry them by placing them in anoven.4.When the tea bags become dry, reweigh them.5.Note the flavour of the tea solution obtained. OBSERVATIONS: RESULT: The tea having better taste has morepolyphenol content. EXPERIMENT - II AIM: Compare the tannic acid content of varioussamples of tea. REQUIREMENTS: Beakers, conical flasks, funnels,heating arrangement, various samples of tea, calciumcarbonate, conc. HCl. THEORY: The tannic acid
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