This document summarizes a chemistry investigatory project on the effect of potassium bisulphite as a food preservative. The student studied the effect of various conditions including: 1) Concentration of sugar and potassium bisulphite on food preservation 2) Temperature on food fermentation 3) Time on food quality deterioration The results showed that increasing the concentration of potassium bisulphite increased preservation time, while higher sugar concentration caused faster decay. Higher temperatures also increased fermentation rate. Over time, even with potassium bisulphite, food quality deteriorated.

1. Techno Academic Sr. Sec. School
Lucknow
(AFFILIATED TO C.B.S.E)
​CHEMISTRY- INVESTIGATORY PROJECT ON THE TOPIC:
Study of effect of Potassium bisulphite as
a food preservative
Submitted to: ​ Submitted by:
1

2. ​“​Intelligence plus character - that is the goal of true education.”
​CERTIFICATE
This is to certify that the project work titled ​“​Study of
effect of Potassium bisulphite as a food preservative”
submitted by ​Saurabh Maurya ​(class XII​th - ​
PCB)in partial
fulfilment of the credit for the chemistry project
evaluation from ​“Techno Academic Sr. Sec. School,
Lucknow”​,as Prescribed by ​CBSE ,​is the bonafide work of
the student done under the guidance and supervision of
Mr. Rajesh Singh, ​Chemistry Teacher, during session
2020-2021​, as a project report.
NAME: SUBJECT:
ROLL NO. : CLASS:
DATE: SCHOOL:
Examiner's sign.
Principal's sign. Teacher's sign.
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3. ACKNOWLEDGEMENT
Our project can never begin without you, dear ​GOD​.
Rather than saying “thank you” to you, you know that we
feel like saying ‘I love you’, to you, always.
We must say thanks to our ​parents who provided us
with sufficient money and help in making this project.
Classmates ​are the real foundation of the project done
by us. Thank you very much. Special thanks to our
Principal​, our ​Vice Principal and our chemistry teachers,
Mr.Rajesh Singh,​who gave support to us and the library
which provides all useful books related to this project.
Next on our thank list are our ​friends, teachers who
really showered constructive feedback and suggestions
without which this project would not have been in present
form.
SaurabhMaurya
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4. ​DECLARATION
We hereby declare that the project work
entitled ​“​Study of effect of Potassium bisulphite as a food
preservative​” ​submitted to the​“Techno Academic Sr.
Sec. School, Lucknow”​, ​is a record of original
work done by us, except for quotations and
summaries which have been duly
acknowledged, under the guidance of
"​Mr.Rajesh Singh, Chemistry Teacher,
TASSS​". The project has not been accepted
for any credits based on investigatory
projects previously.
SAURABH MAURYA
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5. ​INDEX
5
SL.NO. TOPIC
PAGE
NO.
1 OBJECTIVE 6
2 INTRODUCTION 7
3 AIM 9
4 APPARATUS REQUIRED 10
5 MATERIALS & CHEMICALS 11
6 THEORY 12
7 PROCEDURE 13
8 EFFECT OF CONCENTRATION OF SUGAR 13
9 EFFECT OF CONCENTRATION OF KHSO​3 14
10 EFFECT OF TEMPERATURE 15
11 EFFECT OF TIME 16
12 RESULTS,CONCLUSIONS & SUGGESTIONS 17
13 BIBLIOGRAPHY 18

6. OBJECTIVE​:​ ​The objective of this
project is to study the effect of
Potassium bisulphite as a food
preservative under various
conditions.
6

7. 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 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, apple and raw
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8. 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 micro-organisms present in foodstuffs
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
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.
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9. A​IM​:​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​.
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10. APPARATUS:
10

11. MATERIALS AND CHEMICALS:
11

12. 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. An ideal method of food preservation
has the following characteristics:
#1.It improves shelf-life and safety by
inactivating spoilage and pathogenic
microorganisms,
#2.It does not change organoleptic (smell,
taste, colour, texture, etc.) and nutritional
attributes,
#3.It does not leave residues,
#4.It is cheap and convenient to apply and
#5.It encounters no objection from
consumers and legislators.
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13. 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.Put 100 gms of fruit jam in each bottle.
2. Add 5.0 gms, 10.0 grams and 15.0 grams of sugar to
bottle No. I, II and III respectively.
3. Add 0.5 gm of KHSO​3​ to each bottle.
4. Mix contents thoroughly with a stirring rod.
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14. 5. Close the bottle and allow them to stand for one
week or 10 days at room temperature.
6. Observe the changes taking place in Jam every day​.
RECORD:
Result: ​The increase in concentration of sugar
causes​ ​fast decaying
(B)Effect of concentration of ​KHSO​3​ :–
1. Put 100 gm of Jam in each bottle.
2. Add 5.0 gm of sugar to each bottle.
3. Take bottles labeled as I, II, III.
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Bottle
No.
Wt. of
jam taken
added
Wt. of
sugar
Wt. of
KHSO​3
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

15. 4. Add 1.0 gm, 2.0 gm and 3.0 gm of KHSO​3​ 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:
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 labeled as I,
II and III.
2. Add 10.0 gm of sugar and 2.0 gm of KHSO​3​ to
bottle No. I, II and III respectively.
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Bottle
No.
Wt. of
jam taken
added
Wt. of
sugar
Wt. of
KHSO​3
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 2.0gm no no no no few
III 100 gms 5.00 gms 3.0 gm no no no no no

16. 3. Mix the contents thoroughly with a stirring rod.
4. Keep bottle No. I 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:
Result:​ The increase in temperature causes
faster fermentation of jam.
(​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.
16
Bottle
No.
Wt. of
jam
taken
added
Wt. of
sugar
Wt. of
KHSO​3
Observations (Days)
1 2 3 4 5
I 100 gms 10.00
gms
2.0gm No
change
No
change
No
change
No
change
No
change
II 100 gms 10.00
gms
2.0 gm No
change
No
change
No
change
No
change
Slight
change
III 100 gms 10.00
gms
2.0 gm No
change
No
change
Slight
change
Some
change
Some
more
change

17. RECORD:
Result: ​With increase of days, the ​quality of the
​jam deteriorates.
RESULTS,​ ​CONCLUSIONS AND SUGGESTIONS
From the experiment, we can conclude that KHSO​3 acts as a viable
food preservative whose increased concentration can increase time
for preservation. But an increase in concentration of sugar content in
the food material causes fast decaying. Also, the experiment shows
that rate of fermentation of food stuff is directly proportional to
temperature conditions. On passage of time, even in the presence of
KHSO​3, ​the food gets spoiled. Though potassium bisulphite is a good
food preservative (class II preservative), it can trigger lung irritation
and asthma. So, our suggestion is that the usage of food
preservatives must be reduced to the extent possible.
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Bottle No.
Observations(Days)
7 14 21
I No ****** ******
II No Taste
changes
******
III No No Unpleasant smell
develops

18. BIBLIOGRAPHY:
Reference books:
▪ NCERT CLASS 12 CHEMISTRY BOOKS- PART
I, II
▪ CONCISE INORGANIC CHEMISTRY - BY
J.D.LEE
▪ NCERT LABORATORY MANUAL - CLASS
12 CHEMISTRY
Reference websites:
▪ www.google.co.in
▪ en.wikipedia.org
▪ www.ncert.nic.in
▪ www.livestrong.com
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