JAWAHAR higher SECONDARY SCHOOL

NEYVELI(AFFLIATED TO C.B.S.E)

SESSION : 2014-2015

CHEMISTRY- INVESTIGATORY PROJECT

ONStudy of effect of Potassium bisulphite as

a food preservative

Submitted to Submitted by MRS.D.SANGEETHA

N.R.ARUN KAUSHIK

Chemistry Teacher, S.BALAJI

CLASS 12, JHSS V.MANOJ PREVEEN Class-12, Section-A “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 S.BALAJI (class XIIth - PCM group) in partial fulfilment of the credit for the chemistry project evaluation from “JAWAHAR HIGHER SECONDARY SCHOOL, NEYVELI” , is the bonafide work of the student done under the guidance and supervision of Mrs.D.Sangeetha, Chemistry Teacher,JHSS during session 2014-2015, as a project report.

NAME: SUBJECT:

REGISTRATION NO. : CLASS:

DATE: PLACE:

INTERNAL EXAMINER EXTERNAL EXAMINER

ACKNOWLEDGEMENTOur 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 sufficient money and help in making of this project.

Mrs.D.Sangeetha, you 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.C.H.Anil Reddy and Mr.G.Venkatesh who gave support to us and library which provides all useful books related to this project.

Next on our thank list are our friends, teachers who really showered constructive feedbacks and suggestions without which this project would not have been in present form.

N.R.ARUN KAUSHIK

V.MANOJ PREVEEN

S.BALAJI

DECLARATION

We hereby declare that the project work entitled “Study of effect of Potassium bisulphite as a food preservative” submitted to the “JAWAHAR HIGHER SECONDARY SCHOOL, NEYVELI” is a record of original work done by us, except for quotations and summaries which have been duly acknowledged, under the guidance of "Mrs.D. Sangeetha, Chemistry Teacher, JHSS ". The project has not been accepted for any credits based on investigatory projects previously.

N. R. ARUN KAUSHIK

V. MANOJ PREVEEN

S. BALAJI

INDEX

SL.NO. TOPICPAGE NO.

1 OBJECTIVE 1

2 INTRODUCTION 2

3 AIM 4

4 APPARATUS REQUIRED 5

5 MATERIALS & CHEMICALS 6

6 THEORY 7

7 PROCEDURE 8

8EFFECT OF CONCENTRATION OF SUGAR 9

9EFFECT OF CONCENTRATION OF KHSO3 10

10 EFFECT OF TEMPERATURE 11

11 EFFECT OF TIME 12

12RESULTS,CONCLUSIONS & SUGGESTIONS 13

13 BIBLIOGRAPHY 14

14 NOTES 14

OBJECTIVE

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

Conditions

Concentration

TemperatureTime

INTRODUCTIONGrowth 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 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 food stuffs and thus prevents it from getting spoilt.

HSO3–(aq) + H+

(aq) H2O(l) + SO2(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.

AIMThe 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.

Requirements

APPARATUS

Requirements

MATERIALS AND CHEMICALS

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. 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.

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.

(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 gms and 15.0 gms of sugar to bottle No. I, II and III respectively.

3. Add 0.5 gm of KHSO3 to each bottle.4. Mix contents thoroughly with a stirring rod.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.

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 NOChan

ge

NOChang

e

NOChang

e

FewChang

e

FewMore

Change

II 100 gms 10.00 gms 0.5 gm NOChan

ge

NOChang

e

FewChang

e

SomeChang

e

Few moreChang

e

III 100 gms 15.00 gms 0.5 gm NOChan

ge

FewChang

e

FewChang

e

SomeChang

e

MoreChang

e

RECORD:

Result: The increase in concentration of sugarcauses fast decaying

(B)Effect of concentration of KHSO3 :–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.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 2.0gm no no no no few

III 100 gms 5.00 gms 3.0 gm no no no no no

Result: The increase in concentration of KHSO3

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 2.0 gm of KHSO3 to bottle No. I, II and III respectively.

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

10.00 gms

2.0gm Nochange

Nochang

e

Nochange

Nochange

Nochange

II 100 gms

10.00 gms

2.0 gm Nochange

Nochang

e

Nochange

Nochange

Slight change

III 100 gms

10.00 gms

2.0 gm Nochange

Nochang

e

Slight change

Some change

Some more

change

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.

Bottle No.Observations(Days)

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

II No Taste changes

******

III No No Unpleasant smell develops

RECORD:

Result: With increase of days, the quality of the

jam deteriorates.

RESULTS, CONCLUSIONS AND SUGGESTIONS

From the experiment, we can conclude that KHSO3 acts as a viable food preservative whose increased concentration can increase time for preservation. But increase in concentration of

sugar content in the food material causes fast decaying. Also, the experiment shows that rate of fermentation of food stuffs is directly proportional to temperature conditions. On passage of time, even in the presence of KHSO3, 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.

BIBLIOGRAPHYReference 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

NOTES