This document is a chemistry project report submitted by a student. It examines the amount of casein present in different milk samples. The project introduces casein and milk, outlines the aim to study casein content, discusses the relevant theory, and describes the materials, procedure, observations, and conclusion. The observations table shows the source, total protein content, and percentage of casein measured in cow, goat, buffalo and store-bought milk.

1. J P Education Academy, 15 – C, Nathmalpur, Green City Road, Gorakhnath,
Gorakhpur – 273 015 |
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J.P. EDUCATION ACADEMY
Live to learn & learn to live
Affiliated to C.B.S.E. Board – New Delhi (10+2)
CHEMISTRY PROJECT
TOPIC: “To Study the amount of Casein present in different
samples of Milk”
SUBMITTED BY: UNDER THE SUPERVISION OF:
ADITYA PRATAP SINGH MISS DEEPIKA TIWARI
CLASS XII – A PGT – CHEMISTRY
Teacher’s Signature Examiner’s Signature Principal’s Signature

2. J P Education Academy, 15 – C, Nathmalpur, Green City Road, Gorakhnath,
Gorakhpur – 273 015 |
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J.P. EDUCATION ACADEMY
ENGLISH MEDIUM C.B.SE. BOARD CO–EDUCATION
Affiliated to C.B.S.E. New Delhi (10+2) / Aff. No. 2131159
15–C, Nathmalpur, Green City Road, Gorakhnath, Gorakhpur–273015
Ph.: (0551) 3251415, Mob.: 9935402452, 9336212362
CERTIFICATE
Student’s Name ADITYA PRATAP SINGH
Std XII Division A Roll No
This to certify that experiment written in the index
has been performed by the student
satisfactorily.
Signature
School Stamp Dated

3. J P Education Academy, 15 – C, Nathmalpur, Green City Road, Gorakhnath,
Gorakhpur – 273 015 |
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Acknowledgement
I express my heartiest and sincere thanks to Miss Deepika Tiwari (Subject Teacher),
Priyamvada Srivastava (Principal) who provided me their valuable time and
information. This project would not have been possible without their valuable
support and guidance. Their continuous support, affectionate encouragement and
patience have greatly eased my burden and made this project possible.
It was a great opportunity for me to work with Chemistry Project, on the topic “To
Study the amount of Casein present in different samples of Milk”. I am indebted to
all for their valuable support and co-operation during the entire tenure of this
project. Not to forget, all those who kept our spirits surging and helped me in
delivering my best.
Last but most important I thank ‘God Almighty’ who guided me and bestowed me
with the wisdom and an opportunity to carry out the project.
Regards
Aditya Pratap Singh
Class: XII–A

4. J P Education Academy, 15 – C, Nathmalpur, Green City Road, Gorakhnath,
Gorakhpur – 273 015 |
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PREFACE
The main objective of a science student is to get as much of practical knowledge as
possible. Being an able to have a practical knowledge by a developing a project is
a lifetime experience. As practical knowledge is as important as theoretical
knowledge we are thankful of having a project.
Through the development of the project I had a great experience of various
strategies that can be apply in development of project. This project is the stepping
a head in our carrier.
I am pleased to present this project. Proper care had been taken in organizing this
project so that it is to comprehend. Also, various scientific concepts have been
implemented.

5. J P Education Academy, 15 – C, Nathmalpur, Green City Road, Gorakhnath,
Gorakhpur – 273 015 |
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INDEX
S.NO DATE TITLE PAGE NO. REMARKS SIGN
1. 14-12-2017 Introduction 6 – 7
2. 14-12-2017 Aim 8
3. 14-12-2017 Theory 9
4. 14-12-2017 Requirements 10 – 12
5. 14-12-2017 Procedure 13
6. 14-12-2017 Observations 14
7. 14-12-2017 Conclusion 15

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Gorakhpur – 273 015 |
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INTRODUCTION
Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of
nutrition for infant mammals (including humans who breastfeed) before they are able
to digest other types of food. Early-lactation milk contains colostrums, which carries the
mother's antibodies to its young and can reduce the risk of many diseases. It contains many other
nutrients including protein and lactose.
As an agricultural product, milk is extracted from non-human mammals during or soon after
pregnancy. Dairy farms produced about 730 million tones of milk in 2011, from 260 million
dairy cows. India is the world's largest producer of milk, and is the leading exporter of skimmed
milk powder, yet it exports few other milk products. The ever increasing rise in domestic
demand for dairy products and a large demand-supply gap could lead to India being a net
importer of dairy products in the future. The United States, India, China and Brazil are the
world's largest exporters of milk and milk products. China and Russia were the world's largest
importers of milk and milk products until 2016 when both countries became self-sufficient,
contributing to a worldwide glut of milk.
FIG. 1 Model of Casein Micelle

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Gorakhpur – 273 015 |
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The major milk protein casein is found only in milk and now here in the world. The composition
of casein is not constant and depends upon the source of milk.
Average composition of milk from different sources is given below:
Source of Milk Water
(%)
Mineral
(%)
Protein
(%)
Fats
(%)
Carbohydrates
(%)
Cow 87.1 0.7 3.4 3.9 4.9
Human 87.4 0.2 1.4 4.0 4.9
Goat 87.0 0.7 3.3 4.2 4.8
Sheep 82.6 0.9 5.5 6.5 4.5
Casein is a major protein constituent in milk and is a mixed phosphor-protein. Casein has
isoelectric pH of about 4.7 and can be easily separated around this isoelectric pH. It readily
dissolves in dilute acids and alkalies. Casein is present in milk as calcium
Casein ate in the form of micelles. These micelles have negative charge and on adding acid to
milk the negative charges are neutralized.
Ca2+ −Caseinate + 2CH3COOH(aq) → Caesin + (CH3COOH)2Ca
FIG. 2 Diagram showing the action of rennet on the Casein Micelle. The enzyme in rennet
cleaves the Casein releasing a large peptide. The surface of the Micelle changes from being
hydrophilic and negatively charged to hydrophobic and neutral. As a consequence, the
Micelle aggregate to trap fat globules and microorganism in developing curd.

8. J P Education Academy, 15 – C, Nathmalpur, Green City Road, Gorakhnath,
Gorakhpur – 273 015 |
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AIM
“To Study the Amount of Casein present
in different samples of Milk”

9. J P Education Academy, 15 – C, Nathmalpur, Green City Road, Gorakhnath,
Gorakhpur – 273 015 |
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THEORY
Natural milk is an opaque white fluid Secreted by the mammary glands of Female mammals. The
main constituents of natural milk are Protein, Carbohydrate, Mineral Vitamins, Fats and Water
and are a complete balanced diet. Fresh milk is sweetish in taste. However, when it is kept for
long time at a temperature of 5 degree it become sour because of bacteria present in air. These
bacteria convert lactose of milk into lactic acid which is sour in taste. In acidic condition casein
of milk starts separating out as a precipitate. When the acidity in milk is sufficient and
temperature is around 36 degree, it forms semi-solid mass, called curd.
FIG. 3 Structure of Milk
FIG. 4

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Gorakhpur – 273 015 |
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REQUIREMENTS
 Beakers [250 ml]
 Filtration Flasks
 Measuring Cylinder
 Glass Rod
 Spatula

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 China Dish
 Dropper
 Weight Machine
 Different samples of milk
 Acetic Acid [10%]

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Gorakhpur – 273 015 |
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
Saturated Ammonium
Sulphate
 Burner
 Water [H2O]
 Filter Paper

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PROCEDURE
A clean dry beaker has been taken, followed by putting 20 ml of cow’s milk into it and
adding 20 ml of saturated ammonium sulphate solution slowly and with stirring. Fat along
with Casein was precipitate out.
The solution was filtered and transferred the precipitates in another beaker. Added about 30
ml of water to the precipitate. Only Casein dissolves in water forming milky solution leaving
fat undissolved.
The milky solution was heated to about 40° C and adds 10% acetic acid solution drop-wise,
when casein got precipitated.
Filtered the precipitate, washed with water and the precipitate was allowed to dry.
Weighed the dry solid mass in a previously weighed watch glass.
The experiment was repeated with other samples of milk.
FIG. 5 Protein Chain with Peptide Bond
NOTE: R = Amino Acid Group
FIG. 6

14. J P Education Academy, 15 – C, Nathmalpur, Green City Road, Gorakhnath,
Gorakhpur – 273 015 |
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OBSERVATIONS
Sample No. Source Content of Proteins % of Casein
1. Cow Milk 0.60 3.00
2. Goat Milk 0.65 3.25
3. Buffalo Milk 0.85 4.20
4. Amul Milk 0.75 3.88

15. J P Education Academy, 15 – C, Nathmalpur, Green City Road, Gorakhnath,
Gorakhpur – 273 015 |
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CONCLUSION
 Different samples of milk contain different percentage of Casein.
FIG. 7