INDIRA GANDHI MEMORIAL

HIGH SCHOOL(DUM DUM)

AISSCE-2024-25
CHEMISTRY INVESTIGATORY PROJECT

NAME – MAHIR MASHDEE

CLASS-XII
ROLL NO.-
 11
BIBLIOGRAPHY
1. WEBSITES:

• www.wikipedia.org

• www.aogie.com

• www.ask.com

• www.pharmaceutical-drugmanufacturers.com

• www.answers.yahoo.com

2. BOOKS:

• Comprehensive Practical Manual for class XII.

• Pradeep's New Course Chemistry.

• NCERT Class XII Part II.

I would like to express my special thanks of gratitude to
my teachers Ms. Pratyusha Sengupta and Mrs.
Shovajita Sikder who gave me the golden opportunity
to do this wonderful project on the topic "Potassium
bisulphite as a food preservative," which also helped
me in doing a lot of research and I came to know about
so many new things for which I can really be thankful
to them.
 This is to certify that this "Chemistry Investigatory
Project" on the topic "Potassium bisulphite as a food
preservative" has been completed by MAHIR MASHDEE
of Class XII under the guidance of my chemistry
teachers Ms. Pratyusha Sengupta and Mrs. Shovajita
Sikder in particular fulfillment of curriculum of CBSE
leading to award of AISSCE Examination of the year
2024—25.

SIGNATURE OF EXTERNAL SIGNATURE OF INTERNAL

 I, MAHIR MASHDEE bearing roll number
hereby declare that the project on the topic "Potassium
bisulphite as a food preservative" has been submitted
to the head of the department of chemistry of Indira
Gandhi Memorial High School, Dum Dum for fulfillment
of standard XII AISSCE 2024—2025. This project has
been done by me, MAHIR MASHDEE under the
supervision of my chemistry teachers Ms. Pratyusha
Sengupta and Mrs. Shovajita Sikder.

SIGNATURE OF STUDENT
SL.NO TOPIC

1 OBJECTIVE

2 INTRODUCTION

3 AIM

4 APPARATUS REQUIRED

5 MATERIALS & CHEMICALS

6 THEORY

7 PROCEDURE

8 EFFECT OF CONCENTRATION OF SUGAR

9 EFFECT OF CONCENTRATION OF KHSO₃

10 EFFECT OF TEMPERATURE

11 EFFECT OF TIME

12 RESULTS, CONCLUSIONS & SUGGESTIONS

13 BIBLIOGRAPHY
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**OBJECTIVE**

The objective of this project is to study the effect of potassium bisulphite as a food preservative
under various conditions.
 **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 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:

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 a
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, apple and raw mango chutney. This is not used for preserving coloured food materials
because sulphur dioxide produced from this chemical is a bleaching agent. Potassium bisulphite on
reaction with acid of the juice liberates sulphur dioxide which is very effective in killing the harmful
microorganisms present in food stuffs and thus prevents it from getting spoilt.

**The advantage of this method is that no harmful chemical is left in the food.** The Manitoba
Agriculture, Food and Rural Initiatives reports that this product works to prevent the growth of
mould, yeast and bacteria in foods. It is also an additive for homemade wine. Potassium bisulphite is
found in some cold drinks and fruit juice concentrates. Sulphites are common preservatives in
smoked or processed meats and dried fruits. In spray form, it may help prevent foods from
discolouring or browning.
 **AIM**

The aim of this project is to study the effect of potassium bisulphite as a food preservative:

i. At different temperatures.

ii. At different concentrations and for different intervals of time.

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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 KHSO3 8

8 Effect of Temperature 9

9 Effect of Time 10
10 BIBLIOGRAPHY 11
 Objective:

The objective of this project is to Study of effect

of Potassium bisulphite as a food preservative under
various conditions

Concentration

Conditions

Time Temperature
 1
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:
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.

2
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)

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 3

Requirements

4
Materials and Chemicals

Requirements

5
 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.
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.

6
 (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.

RECORD:

Bottle Wt. of Wt. of Wt. of Observations (Days)

No. jam taken sugar KHSO3 1 2 3 4 5
added

I 100 gms 5.00 gms 0.5gm NO NO NO Few Few

Change Change Change Change More
Change

II 100 gms 10.00 gms 0.5 gm NO NO Few Some Few

Change Change Change Change more
Change

III 100 gms 15.00 gms 0.5 gm NO Few Few Some More
Change Change Change Change Change

Result: The increase in concentration of sugar

causes fast decaying
7
 (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:

Bottle Wt. of Wt. of Wt. of Observations (Days)

No. jam taken sugar KHSO3 1 2 3 4 5
added

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
 (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:

Bottle Wt. of Wt. of Wt. of Observations (Days)

No. jam taken sugar KHSO3 1 2 3 4 5
added

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 Some Some
Ferme Ferme more
-nted -nted Ferme
-nted

Result: The increase in Temperature causes

fast fermentation of jam
9
 (D) Effect of time: –

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:

Observations(Days)
Bottle No. 7 14 21
I No ****** ******
II No Taste ******
changes
III No No Unpleasant smell
developes

Result: With increase of days, the quality of the

jam deteriorates.

10