TO STUDY THE QUANTITY
OF CASEIN
PRESENT IN
DIFFERENT SAMPLES OF
MILK
Made By
S. GIRI PRASANNA
XII – A
KENDRIYA VIDYALAYA NO.1
JIPMER CAMPUS, PUDUCHERRY.
CHEMISTRY INVESTIGATORY PROJECT
CERTIFICATE
Certified that this project work is done by ________________________.
Registration Number __________ under my supervision in partial fulfilment of
AISSCE Practical Examination – 20 conducted by the Central Board of
Secondary Education
Internal Examiner
External examiner
Principal
SHRI JOSE MATHEW
KV NO.1, JIPMER CAMPUS, PUDUCHERRY
ACKNOWLEDGEMENT
I, GIRI PRASANNA.S, feel proud to present my Investigatory project
in Chemistry on the topic “study of casein present in different samples
of milk” which aims to analyse the presence of casein in milk.
I wish to express my deep gratitude and sincere thanks to the
Principal, Shri Jose Mathew for his encouragement and for all the
facilities that he provided for this project work.
This project wouldn’t have been feasible without the proper and
rigorous guidance of my Chemistry teacher Mrs. Nekki Yadav who
guided me throughout this project in every possible way. An
investigatory project involves various difficult lab experiments which
have to be carried out by the student to obtain the observations and
conclude the report on a meaningful note. These experiments are very
critical and in the case of failure, may result in disastrous
consequences Thereby, I would like to thank Mrs. Nekki Yadav for
guiding me on a step by step basis and ensuring that I completed all
my experiments with ease.
INDEX
S.NO.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
TOPIC
ACKNOWLEDGEMENT
INTRODUCTION
ABOUT CASEIN
AIM
REQUIREMENTS
THEORY
PROCEDURE
OBSERVATIONS
CONCLUSION
BIBLIOGRAPHY
PAGE
3
5
6
7
7
8
9
10
11
12
INTRODUCTION
Milk is a white fluid secreted by the mammary glands
of living organisms. It is the food of exceptional inters
probability. Milk is also known to contain all sorts of
micronutrients essential for a body of an organism. The
major milk protein Casein is found only in milk and
nowhere in the world. The composition of milk from
different sources is given below:
SOURCE WATER MINERAL PROTEIN FATS
OF MILK
(%)
(%)
(%)
(%)
COW
HUMAN
GOAT
SHEEP
87.1
87.4
87
82.6
0.7
0.2
0.7
0.9
3.4
1.4
3.3
5.5
3.9
4.0
4.2
6.5
CARBOHYDRATES
(%)
4.9
4.9
4.8
4.5
ABOUT CASEIN
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 the isoelectric pH. It readily
dissolves in dilute acids and alkalies. Casein is
present in milk as calcium caseinate in the
form of micelles. These micelles have
negative charge and on adding acid to milk,
the negative charges are neutralized.
This is how ALPHA CASEIN structure looks
like:
Aim
To study the quantity of casein in different
samples of milk.
REQUIREMENTS
1. Beakers(250 ml)
2. Filter Paper
3. Glass Rod
4. Weight Box
5. Filtration Flask
6. Buchner Funnel
7. Test Tubes
8. Porcelain
9. Different samples of Milk
10. 1% of Acetic acid solution
11. Ammonium Sulphate Solution
THEORY
Natural Milk is an opaque white fluid secreted
by the mammary glands of female mammal.
The main constituent of natural milk are
Protein, Carbohydrate, Mineral, Vitamins, Fats
and Water and is 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 becomes 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.
PROCEDURE
1. A clean dry beaker has been taken, followed by
putting 20ml of saturated ammonium sulphate
solution slowly and with stirring. Fat along with
casein was precipitate out.
2. The solution was filtered and transferred the
precipitates to another beaker. Added about 30ml
of water to the precipitate. Only casein dissolves in
water forming milky solution leaving fat
undissolved.
3. The milky solution was heated to about 40 degrees
and add 1% of acetic acid solution drop-wise,
when casein got precipitated.
4. Filtered the precipitate. Washed with water and
the precipitate was allowed to dry.
5. Weighed the dry solid mass in a previously
weighed watch glass.
6. The experiment was repeated with other samples
of milk.
OBSERVATIONS
After following the above procedure, the final
observations we get are:
SAMPLE
NO.
1.
2.
3.
4.
CONTENTS AMOUNT
SOURCE
OF
OF
PROTEIN
CASEIN
(g/ml)
Cow Milk
0.60
0.5
Goat Milk
0.65
0.34
Buffalo
0.85
0.4
Milk
Packet
0.75
0.39
Milk
% OF
CASEIN
5
3.25
4.20
3.88
CONCLUSION
According to above brief analysis of casein milk, we
are able to conclude that:
1. Amount of casein present in Cow Milk is 5%.
2. Amount of casein present in Goat Milk is 3.25%.
3. Amount of casein present in Buffalo’s Milk is
4.2%.
4. Amount of casein present in Packet Milk is
3.88%.
So according to above analysis, we can finally
conclude the Cow Milk is the best milk or
beneficial milk for human beings.
BIBLIOGRAPHY
 Comprehensive Practical Chemistry Class 12
 http://www.google.com/=casein+milk
 http://en.wikipedia.org/wiki/Casein