Parmeshwari Devi Dhanuka Saraswati

VidhyaMandir(Residential)Gaushala Nagar Vrindaban

(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. G.K. Lawaniya Ravindra Pratap Singh

H.O.D. Chemistry 12th Science

Roll no. =

C ertificate

This is to certify that Ravindra

Pratap Singh s/o Mr. Amar Singh is a

bonafide student of class XIIth

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. Shishupal Singh G.K. Lawaniya

(Head of the institution) (H.O.D. Chemistry)

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. G.K. Lawaniya, 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.

Ravindra Pratap Singh

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 KHSO3 8

8 Effect of Temperature 9

9 Effect of Time 10

Objective:

The objective of this project is to Study of effect of Potassium bisulphite as a food preservative under various conditions

Conditions

Concentration

TemperatureTime

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

1

chemical preservatives which are permitted for use are:

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 juice liberates Sulphur dioxide which is very effective in killing the harmful micro-organisms present in food and thus prevents it from getting spoiled.

HSO3–

(aq) + H+ (aq) H2O(l) + SO2(g)

2

Requirements

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 andiii. For different intervals of time.

Apparatus 3

Requirements

Materials and Chemicals4

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 KHSO3 as preservative depends upon its concentration under different conditions which may be determined experimentally.

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.

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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 KHSO3, 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.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.

BottleNo.

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 NOChange

NOChange

NOChange

FewChange

FewMoreChange

II 100 gms 10.00 gms 0.5 gm NOChange

NOChange

FewChange

SomeChange

Few moreChange

III 100 gms 15.00 gms 0.5 gm NOChange

FewChange

FewChange

SomeChange

MoreChange

6

RECORD:

Result: The increase in concentration of sugarcauses fast decaying

(B)Effect of concentration of KHSO3 :–

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.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:

BottleNo.

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 KHSO3

increase more time of preservation

8

7

(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.

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:

BottleNo.

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 FewFerme-nted

SomeFerme-nted

Some more Ferme-nted

Result: The increase in Temperature causes fast fermentation of jam

(D)Effect of time: – 9

1. Take three bottles and label them as I, II and III.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.4. Note the changes taking place in each bottle and

record the observations.

RECORD:

Bottle No.Observations(Days)

7 14 21I No ****** ******

II No Taste changes

******

III No No Unpleasant smell

developes

Result: With increase of days, the quality of the jam deteriorates.

10