ACKNOWLEDGMENT

I would like to take this opportunity to thank Mrs Malwinder Kaur, who has been a guiding force for my project report on ‘TANNIC ACID CONTENT OF VARIOUS SAMPLES OF TEA’.

I am also thankful to my friends for their support and encouragement in finding out appropriate material for this work without their help it was not possible to write this report

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Aim:-

‘To compare the tannic acid contents of various samples of tea’.

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Introduction:-

Now days the market is flooded with various brands of tea manufactures and marketed by local companies as well as reputed firms. It is difficult choice for buyers to pick up approximate brand as toxin contents vary from one brand to another brand.

People are not aware of the fact that suitable means are available to test the toxin contents for each brand available in the market which may enable them to test the quality of tea. Most of the people rely on experience and taste to choose a suitable brand. But this is not suitable method

Tannic acid is in fact a slow poison, which accumulates in the body. It has been found to be responsible for certain heart disorders which can cause even death of human beings.

This project is an attempt to evaluate the tannic acid content in various popular brands of tea which are available in the market.

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Theory:-

Tea is made from young leaves and buds of the tea plant. The brownish colour of tea is due to the presence of polyphenolic compounds and some inorganic ions. The tea leaves are rich in caeffin acid.

The tannic acid present in tea leaves is precipitated as calcium tannate by treatment of aqueous solution of tea with calcium carbonate. Calcium carbonate is then hydrolyzed with concentrated HCL and recrystallised from water.

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Apparatus Used:-

Test tubesTest tube standBeakers Chemical balanceWeight boxMeasuring flaskConical flask

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Procedure:-

Weigh 10gm of each of the given samples of tea leaves.

Take 100ml of distilled water in a 400ml beaker and boil it. Then add the first sample of tea leaves to it and boil for 10 minutes then cool and filter the solution

To the filtrate add about 2gm of solid calcium carbonate and boil the contents .tannic acid gets precipitated as calcium tannate by filtration.

Calcium tannate obtained is hydrolysed by warming up with 4 to 5 ml of concentrated HCL. Tannic acid obtained is crystallized from water and weighed.

Repeat the steps with other samples of tea and record the observations.

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Observations:-

CALCUATIONS:-

Percentage of tannic acid =(W2/W1)*100

Result:-

% of a tannic acid in TETLEY tea is =

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Sr No Name of Brand Weight of tea(W1)

Weight of Tannic acid(W2)

1. TETLEY

Observations:-Sr No.

Name of brand

Weight of tea(W1)

Weight of tannic acid(W2)

2. Tata tea

Calculations:-

Percentage of tannic acid=(W2/W1)*100

=

=

Result:-

% of tannic acid in TATA TEA is=

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Observations:-

Sr no. Name of brand Weight of tea(W1) Weight of Tannic acid(W2)

3. LIPTON TEA

Calculations:-

Percentage of tannic acid=(W2/W1)*100

=

=

Result:-

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% of tannic acid in Tetley Tea is=

Observations:-

Sr no Name of brand

Weight of Tea(W1)

Weight of tannic acid (W2)

4 Taj Mahal

Calculations:-

Percentage of tannic acid= (W2/W1)

=

=

Result:-

% of tannic acid in TAJ MAHAL tea is=

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Observations:-

Sr no.

Brand name of tea

Weight of tea leaves taken(X gm)

Weight of tannic acid obtained(Y gm)

% of tannic acid = Y/X * 100

1. Lipton tea

10gm 0.14gm 1.4%

2. Tata Gold

10gm 0.35gm 3.5%

3. Tetley Tea

10gm 0.50gm 5%

4. Taj Mahal

10gm 0.34gm 3.4%

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Conclusions:-

From the above observations following conclusions can be drawn:

1. Lipton tea contains less amount of tannic acid (1.4%).2. Tata Gold and Taj Mahal contains nearly same amount of

tannic acid (3.5%).3. Tannic acid is very high (5%) in Tetley Tea.

Recommendations:-

1. Customers are advised to use lipton tea.

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References:-

1. NCERT text book for class XI.

2. Google

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