DELHI PUBLIC SCHOOLDAGAPUR , SILIGURI(Affiliated to C.B.S.E.)

Session :- 2012-13Topic :Study of effect of Potassium bisulphite as a food preservative

Submitted To:Submitted By:Mr. B.GHOSHH.O.D. Chemistry 12th ScienceRoll no. = "The ladder of success doesn't care who climbs it."

Certificate

This is to certify that 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. S.P. DAS Mr. B.GHOSH(Head of the institution)(H.O.D. Chemistry)Success is not final, failure is not fatal

Acknowledgement

Acknowledgement is the most beautiful page in any projects 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. B.GHOSH, 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.

Index

S. No.ContentsPage no.

1.Objective1

2.Introduction2

3Apparatus4

4Materials and Chemicals5

5Theory & Procedure6

6Effect of concentration of sugar7

7Effect of concentration of KHSO38

8Effect of Temperature9

9Effect of Time10

Objective:

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

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 andiii. For different intervals of time.3

ApparatusRequirements

BeakerConical flasks (100 ml)

Peeler

Pestle and mortarGlass Bottles

Knife4Glass rodBalance

Materials and ChemicalsRequirements

PotassiumBisulphite

SugarFresh Fruits

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.BottleNo.Wt. of jam taken addedWt. of sugarWt. of KHSO3Observations (Days)

12345

I100 gms5.00 gms0.5gmNOChangeNOChangeNOChangeFewChangeFewMoreChange

II100 gms10.00 gms0.5 gmNOChangeNOChangeFewChangeSome ChangeFew moreChange

III100 gms15.00 gms0.5 gmNOChangeFewChangeFewChangeSomeChangeMoreChange

RECORD:Result: The increase in concentration of sugarcauses 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:BottleNo.Wt. of jam taken addedWt. of sugarWt. of KHSO3Observations (Days)

12345

I100 gms5.00 gms1.0gmnononofewsome

II100 gms5.00 gms1.0 gmnonononofew

III100 gms5.00 gms1.0 gmnonononono

Result: The increase in concentration of KHSO3increase 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 0C, bottle No. II at room temperature (25C) and bottle No. III in a thermostat at 50C. Observe the changes taking place in the jam for 10 days.RECORD:BottleNo.Wt. of jam taken addedWt. of sugarWt. of KHSO3Observations (Days)

12345

I100 gms5.00 gms2.0gmnonononono

II100 gms10.00 gms2.0 gmnonononoFew Ferme-nted

III100 gms15.00 gms2.0 gmnonoFewFerme-ntedSomeFerme-ntedSome more Ferme-nted

Result: The increase in Temperature causes fast fermentation of jam9

(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:Bottle No.Observations(Days)

71421

INo************

IINoTaste changes******

IIINoNoUnpleasant smell developes

Result: With increase of days, the quality of thejam deteriorates.10