KHSO3 as Preservative

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DELHI PUBLIC SCHOOL

DAGAPUR , SILIGURI

(Affiliated to C.B.S.E.)

Session :- 2012-13

Topic :

Study of effect of Potassium

bisulphite

as a food

preservative

Submitted To:

Submitted By:

Mr. B.GHOSH

H.O.D. Chemistry

12

th

Science

Roll no. =

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C

ertificate

This is to certify that

s/o Mr. Amar Singh is a bonafide

student of class XII

th

_{Science during}

session 2012-2013. He has completed

his project on

Study of effect of

Potassium bisulphite as a food

preservative

successfully under my

guidance and supervision.

Mr. S.P. DAS

Mr. B.GHOSH

(Head of the institution)

(H.O.D.

Chemistry)

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Acknowledgement

Acknowledgement is the most beautiful page in any project’s final pages. More than a formality, this appears to me the best opportunity to express my gratitude.

My project can never begin without you, dear GOD. Rather than saying “thank you” to you, you know that I feel like saying ‘I love you’, to you, always.

I must say thanks to my parents who provide me sufficient money and help in making of this project.

Mr. B.GHOSH , you are real foundation of the project done by me. My project would never have been possible without your guidance. Thank you very much.

Special thanks to my principal who gave support to me and library which provides me helpful books related to this project.

Next on my thanks lists are my friends, teachers, students who really showered constructive feedbacks and suggestions without which this project would not have been in present form.

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INDEX

S. No. Contents Page no. 1. _Objective ₁ 2. _Introduction ₂ 3 _Apparatus ₄

4 _{Materials and Chemicals} ₅

5 _{Theory & Procedure} ₆

6 _{Effect of concentration of sugar} ₇

7 _{Effect of concentration of KHSO}₃ ₈

8 _{Effect of Temperature} ₉

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Conditions

ConcentrationTemperature

Time

Objective:

The objective of this project is to Study of effect of

Potassium bisulphite as a food preservative under

various conditions

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Introduction

Growth of microorganisms in a food material can

be inhibited by adding certain chemical substances.

However the chemical substances should not be

harmful to the human beings. Such chemical

substances which are added to food materials to

prevent their spoilage are known as chemical

preservatives. In our country, two chemical

preservatives which are permitted for use are:

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1. Benzoic acid(or sodium benzoate)

2.Sulphur dioxide(or potassium bisulphite)

Benzoic acid or its sodium salt, sodium benzoate

is commonly used for the preservation of food

materials. For the preservation of fruits, fruit

juices, squashes and jams sodium benzoate is used

as preservative because it is soluble in water and

hence easily mixes with the food product.

Potassium bisulphite is used for the preservation of

colourless food materials such as fruit juices, squashes,

apples and raw mango chutney. This is not used for

preserving coloured food materials because Sulphur

dioxide produced from this chemical is a bleaching

powder. Potassium bisulphite on reaction with acid of the

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juice liberates Sulphur dioxide which is very effective in

killing the harmful micro-organisms present in food and

thus prevents it from getting spoiled.

HSO

3–(aq)

+ H

+ (aq)—————>

H

2

O

(l)

+ SO

2(g)

The advantage of this method is that no harmful

chemical is left in the food.

The aim of this project is to study the effect of

potassium bisulphite as food preservative.

i. At different temperatures.

ii. At different concentrations and

iii.

For different intervals of time.

Apparatus

(9)

Requirements

Beaker

Conical

flasks

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Materials and Chemicals

Peeler Pestle and mortar Glass Knife

4

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Requirements

Potassium Bisulphite

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Theory

Food materials undergo natural changes due to

temperature, time and enzymatic action and become

unfit for consumption. These changes may be checked by

adding small amounts of potassium bisulphite. The

effectiveness of KHSO

3

as preservative depends upon

its concentration under different conditions which may

be determined experimentally.

Sugar Fresh _Fruits

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Procedure:

1. Take fresh fruits, wash them thoroughly with water

and peel off their outer cover.

2. Grind it to a paste in the mortar with a pestle.

3. Mix with sugar and colouring matter.

4. The material so obtained is fruit jam. It may be

used to study the effect of concentration of sugar

and KHSO

3

, temperature and time.

(A) Effect of concentration of

Sugar:

-1. Take three wide mouthed reagent bottles labeled as I II III.

2. Put 100 gms of fruit jam in each bottle.

3. Add 5.0 gms, 10.0 gms and 15.0 gms of sugar to bottle No. I, II and III respectively.

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4. Add 0.5 gm of KHSO3 to each bottle.

5. Mix contents thoroughly with a stirring rod.

6. Close the bottle and allow them to stand for one week or 10 days at room temperature.

7. Observe the changes taking place in Jam every day.

Bottle No. Wt. of jam taken added Wt. of sugar Wt. of KHSO3 Observations (Days) 1 2 3 4 5 I 100 gms 5.00 gms 0.5gm NO Change NO Change NO Change Few Change Few More Change II 100 gms 10.00 gms 0.5 gm NO Change NO Change Few Change Some Change Few more Change III 100 gms 15.00 gms 0.5 gm NO Change Few Change Few Change Some Change More Change RECORD:

Result:

The increase in concentration of sugar

causes

fast decaying

(B)

Effect of concentration of

KHSO

3

:–

1. Take bottles labeled as I, II, III. 2. Put 100 gm of Jam in each bottle. 3. Add 5.0 gm of sugar to each bottle.

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4. Add 1.0 gm, 2.0 gm and 3.0 gm of KHSO3 to bottle No. I,

II and III respectively.

5. Mix the contents thoroughly with a glass rod.

6. Keep all the bottles at room temperature for about 10 days and observe the changes everyday.

RECORD:

Bottle No. Wt. of jam taken added Wt. of sugar Wt. of KHSO3 Observations (Days) 1 2 3 4 5 I 100 gms 5.00 gms 1.0gm _no _no _no _{few some} II 100 gms 5.00 gms 1.0 gm _no _no _no _no _few III 100 gms 5.00 gms 1.0 gm _no _no _no _no _no

Result:

The increase in concentration of KHSO

3

increase

more time of preservation

(C) Effect of

temperature: –

1. Take 100 gm of Jam in three bottles lebelled as I, II and III.

2. Add 10.0 gm of sugar and 1.0 gm of KHSO3 to each bottle.

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3. Mix the contents thoroughly with a stirring rod.

4. Keep bottle No. I in the refrigerator at 0˚C, bottle No. II at room temperature (25˚C) and bottle No. III in a

thermostat at 50˚C. Observe the changes taking place in the jam for 10 days.

RECORD: Bottle No. Wt. of jam taken added Wt. of sugar Wt. of KHSO3 Observations (Days) 1 2 3 4 5 I 100 gms 5.00 gms 2.0gm _no _no _no _no _no II 100 gms 10.00 gms 2.0 gm _no _no _no _no Few Ferme-nted III 100 gms 15.00 gms 2.0 gm _no _no Few Ferme -nted Some Ferme -nted Some more Ferme-nted

Result:

The increase in Temperature causes

fast fermentation of jam

(D)

Effect of

time: –

1. Take three bottles and label them as I, II and III.

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2. To each bottle add 25 g of Jam and 1 g of potassium bisulphite.

3. Keep bottle I for 7 days, bottle II for 14 days and bottle III for 21 days at room temperature.