AMITY INTERNATIONAL SCHOOL

SESSION 2024-25
CHEMISTRY PROJECT
TOPIC: “STUDY OF EFFECT OF POTASSIUM BISULPHITE
AS FOOD PRESERVATIVE UNDER VARIOUS CONDITIONS “

Submitted by Submitted to
MOHD AHAD KHAN RATNESH SIR

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 Authenticity Certificate

SESSION : 2024-25

THIS IS TO CERTIFY THAT MOHD AHAD KHAN OF AMITY INTER-

NATIONAL SCHOOL OF CLASS XII HAS COMPLETED HIS PROJECT
ON THE TOPIC “STUDY OF EFFECT OF POTASSIUM BISULPHITE AS
FOOD PRESERVATIVE UNDER VARIOUS CONDITIONS” DONE UN-
DER THE SUPERVISION AND GUIDANCE OF OUR CHRMISTRY SIR
Mr. RATNESH SIR IN SESSION 2024-25 AND THIS PROJECT HAS
BEEN CERTIFIED TO NEXT ACADEMIC SESSION SATISFACTORILY.

Signature of Examiner : Date :

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 ACKNOWLEDGEMENT
I, MOHD AHAD KHAN of class XII would like to
express my gratitude towards my chemistry
teacher Mr. RATNESH SIR who gave me this
golden opportunity to explore my skills and im-
agination towards the project entitled as “study
of effect of potassium bisulphate as food pre-
servative under various conditions” and my al-
mighty of course my parents, coworkers and
friends who took this project to next level.

MOHD AHAD KHAN

Class XII

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 INDEX
S. NO. CONTENTS PAGE NO.

1 Purpose of the project 5

2 Introduction 6-7
3 Description of apparatus used in 8
this project
4 Food preservation 9-10
5 Need for food preservation 11
6 Principles of food preservation 12
7 Role of food preservation 13
8 Procedure of food processing 14
9 Procedure 15
10 Study of effect of concentration 16-17
of potassium bisuphite and the
effect of time
11 Study of effect of temperature 18
12 Conclusion 19
13 Safety measures while using 20
KHSO3 as food preservative

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 PURPOSE OF THE PROJECT

The Purpose Of This Project Is To Study The

Effect Of Potassium Bisulphite As a Food Pre-
servative Under Various Conditions Such As
Given Below:

 CONCENTRATION : In chemistry, concentration

can be defined as the measure of the relative proportions

of two or more quantities in a mixture.

 TIME : Time is nothing but the measure of amount of

concentration during any process or activity taking place

on that particular level within the completion of the ac-
tion took place during that process.

 TEMPERATURE : Temperature is the degree or

intensity of heat of that substance which is ex-
pressed according to a comparative scale in graph
and shown by a thermometer.

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 INTRODUCTION
WHAT ARE PRESERVATIVES?
Growth of micro – organisms in a food material can be
inhibited by adding certain chemical substance. How-
ever, 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 permit-
ted for use are:

1. Benzoic acid ( or sodium benzoate i.e.

C7H6O2 )
2. Potassium hydrogen sulphite (or po-
tassium bisulphite i.e. KHSO3) .
 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 it is used as pre-
servative because it is soluble in water and hence
easily mixes with the food product. The efficacy of
benzoic acid and benzoate is thus dependent on
the PH of the food.
 POTASSIUM BISULPHITE is used for the
preservation of colourless food materials such as
fruit juices, squashes, apples and raw mango
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 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 effec-
tive in killing the harmful micro – organisms pre-
sent 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 the project
is to study the effect of potassium bisulphite as
food preservative:

1. At different temperatures,

2. At different concentrations and

3. For different intervals of time.

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DESCRIPTION OF APPARATUS WE ARE GOING
TO USE IN THIS PROJECT ARE AS FOLLOWS :
1) CONICAL FLASKS – It is a glass laboratory flask of a
conical profile with a narrow tubular neck and a flat bottom,
used to manipulate solutions or to carry out titrations.

2) GLASS ROD – a glass rod is a piece of equipment used

to mix chemical and liquids for laboratory purposes. After
every use of glass rod it is recommended that it should be
cleaned to avoid contamination. It is also used as an aid for
transferring the liquid into the funnel.

3) KNIFE – A knife is a tool with cutting edge or blade at-

tached to a handle.

4) APPLE – Apple is a kind of fruit which will help us in

making jam in this experiment.

5) SUGAR – Sugar is nothing but the sweet – tasting, solu-

ble carbohydrates, which we use in our food sometimes.
Simple sugars are called monosaccharide and include glu-
cose (also known as dextrose), fructose, galactose.

6) POTASSIUM BISULPHITE – It is a chemical com-

pound with the chemical formula KHSO3 It is used during the
production of alcoholic beverages as a sterilizing agent .
It is made by the reaction sulphur dioxide and the reaction of
potassium carbonate.
The sulfur dioxide is passed through a solution of the potas-
sium carbonate until no more carbon dioxide is given off. The
solution is concentrated and then allowed to crystallize.

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 MATERIALS REQUIRED FOR THIS PROJECT:

GLASS ROD
SUGAR

CONICAL
FLASKS

(100 Ml) APPARATUS

THAT IS
REQUIRED

APPLES
POTASSIUM
KNIFE
BISULPHITE

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FOOD PRESERVATION
->How we can preserve our food?
We can preserve our food by following methods:

->TRADITIONAL TECHNIQUES:
 CURING :
The earliest form of curing was dehydration or drying, Smok-
ing and salting techniques improve on the drying process and
add antimicrobial agents that aid in preservation. Smoke de-
posits a number of pyrolysis products onto the food, including
the phenols syringol guaiacol and cathechol.Salt accelerates
the drying process using osmosis and also inhibits the growth
of several common strains of bacteria. More recently nitrites
have been used to cure meat, contributing a characteristic
pink colour.[6]

 COOLING :
Cooling preserves food by slowing down the growth and re-
production of microorganisms and the action of enzymes that
causes the food to rot. Before the era of mechanical refrigera-
tion, cooling for food storage occurred in the forms of root cel-
lars and iceboxes. Today, root cellaring remains popular
among people who value various goals, including local
food, heirloom crops, traditional home cooking tech-
niques, family farming, frugality, self-sufficiency, organic
farming, and others.

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  FREEZING :

Freezing is also one of the most commonly used processes,

for preserving a very wide range of foods. For example, pota-
to waffles are stored in the freezer, but potatoes themselves
require only a cool dark place to ensure many months' stor-
age. Cold stores provide large-volume, long-term storage for
strategic food stocks held in case of national emergency in
many countries.

MODERN INDUSTRIAL TECHNIQUES :

 PASTEURIZATION:
Pasteurization is a process for preservation of liquid food. In
this method, milk is heated at about 70 °C (158 °F) for 15–30
seconds to kill the bacteria present in it and cooling it quickly
to 10 °C (50 °F) to prevent the remaining bacteria from grow-
ing. The milk is then stored in sterilized bottles or pouches in
cold places. This method was invented by Louis Pasteur,
a French chemist, in 1862.

 ARTIFICIAL FOOD ADDITIVES :

Preservative food additives can be antimicrobial — which in-
hibit the growth of bacteria or fungi, including mold - or anti-
oxidant, such as oxygen absorbers, which inhibit
the oxidation of food constituents. Common antimicrobial
preservatives include calcium propionate, sodium nitrate,
sodium nitrite, sulfites (sulfur dioxide, sodium bisul-
fite, potassium hydrogen sulfite, etc.), and EDTA.

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  BIOPRESERVATION :
Biopreservation is the use of natural or controlled micro biota
or antimicrobials as a way of preserving food and extending
its shelf life. Beneficial bacteria or the fermentation products
produced by these bacteria are used in biopreservation to
control spoilage and render pathogens inactive in food. Lac-
tic acid bacteria have antagonistic properties that make them
useful as biopreservatives.

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->NEED FOR FOOD PRESERVATION

Preservation of food is done during the months when food is

available at large quantity and therefore at large cost. Rea-
sons of food preservation are as follows:

1) One of the reason of food preservation is that to take

care of the excess produce.
2) The second reason is that they add variety in our meals.
3) Makes transportation of food cheap and easier for us to
live and survive.

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->PRINCIPLES OF FOOD PRESERVATION

A good method of food preservation is one that slows

down or prevents altogether the action of the agents of
spoilage. Also, during the process of food preservation it
shouldn’t be damaged. The principles of food preserva-
tion are as follows:

a) Removal of micro – organisms or inactivating

them: This is done by air, water (moisture), lower-
ing or increasing temperature, increasing the con-
centration of salt or sugar or acid in foods. F or the
preservation of green leafy vegetables, the water
should be removed from the leaf so that micro or-
ganisms cannot survive. This is done by drying the
green leaves till all the moisture evaporates.
b) Inactivating enzymes: Enzymes found in
foods can be inactivated by changing their condi-
tions such as temperature or moisture. One of the
method for preservation of peas is that to put them
in boiling water for few minutes. It will inactivate the
enzymes present in peas.

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->ROLE OF FOOD PRESERVATION
1. Eliminates any potential microbiological harm to the
consumer.

2. Maintains quality of food (sensory perceptions)

3. Maintains nutritional value within the food product.

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PROCEDURE OF FOOD
PROCESSING

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 PROCEDURE
1. Take 500 g fresh apples. Wash them thoroughly
and peel off the outer layer. Remove the seeds and
crush the apples in a mixer.

2. Add about 100 g of sugar and heat the contents

slowly for about 10 minutes to prepare jam.

3. During heating keep on stirring the contents.

4. Use this jam for performing the following experi-

ments.

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->STUDY OF EFFECT OF CONCENTRATION OF
POTASSIUM BISULPHITE AND THE EFFECT OF
TIME
1) Add 50 g of jam in each of the four conical flasks .

2) To flask A add 0.1 g , flask B 0.2 g , flask C 0.5 g and

flask D 1.0 g of potassium bisulphate.
3) Mix the contents in each flask an leave them undis-
turbed at room temperature.
4) For some days check for any growth of micro – organ-
isms after each day and record the observations in a ta-
ble.

OBSERVATIONS:
Sample Wt. of Wt. Wt. of Observation (Days)
No. of Jam of KHSO3
1 2 3 4 5
Bottle Added Sugar

A) 50 g 5g 0.1 g No No No Few Few

change change change change more
change

B) 50 g 10 g 0.2g No No Some Some Few

change change change change more
change

C) 50 g 15 g 0.5 g No Few Some Some More

change change change change change

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RESULT: As the concentration of potassium bisul-
phite is increased, the growth of micro – organisms ap-
pears after more days.The minimum concentration of po-
tassium bisulphate required for preserving jam is ap-
proximately 1 % .

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->STUDY OF EFFECT OF TEMPERATURE
1) Take three conical flasks and label them as A, B and
C. Add 50 g of jam in each of the three flasks.
2) Add 0.5 of potassium bisulphate to each of the three
conical flasks.
3) Keep flask A in a refrigerator, flask B at room tem-
perature and flask C in an oven maintained at a tem-
perature of 60 ◦ c , leave them undisturbed for few
days.
4) Check for any growth of micro - organisms after
each day and record the observations.

OBSERVATIONS :
Sample Wt. of Wt. of Wt. of Observation (Days)
No. of Jam Sugar KHSO3
1 2 3 4 5
Bottle Added

A) 50 g 5g 0.5 g No No No Few Some

B) 50 g 5g 0.5 g No No No No Few

C) 50 g 5g 0.5 g No No No No No

RESULT: The growth of micro – organisms occurs

earliest in the flask kept at room temperature. The
preservation of jam by potassium bisulphate is maximum
at lower temperature (0-5◦ C).

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->CONCLUSIONS OF THIS PROJECT:
This experiment shows us that KHSO3 is the
viable food preservative whose increased
concentration can increase time for preserva-
tion .The fermentation of food present is di-
rectly proportional to temperature conditions.

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->SAFETY MEASURES WHILE USING
KHSO3 AS FOOD PRESERVATIVE :
People with sulphite sensitivity might react poorly to potassi-
um bisulphite. A sulphite sensitivity usually causes asthma
symptoms such as wheezing or difficulty breathing. Some
people may also experience anaphylaxis, which is a life-
threatening allergic reaction. If you have a sensitivity to sul-
phites, you should avoid any food that contains potassium bi-
sulphite .

->How It Works ?
When potassium bisulphite is dissolved in water, it forms a
sulfurous acid. The acid lowers the pH of the food, which
helps inhibit the growth of harmful organisms, including bac-
teria such as E. coli, as well as yeast and mold. The bisul-
phite oxidize and lose some of its antimicrobial power.also
prevents browning or discoloration of food Potassium bisul-
phite is more stable than potassium sulfite. In humid condi-
tions, however, the dry salt may

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