2. KENDRIYA VIDYALAYA NEW CANTT.
ALLAHABAD
DEPARTMENT OF CHEMISTRY
CERTIFICATE
This is to be certify that ABHINAVKUMAR SINGH , a
student of class XII-A has successfully completed the
research on the below mentioned project under the
guidance of Mr. ASHOKKUMAR , chemistry teacher
during the year 2016-17in fulfilment of chemistry
practical examination.
Signature
3. ACKNOWLEDGEMENT
I wish to express my deep gratitude and sincere
thanks to the Principal, B.B. SINGH, Kendriya
Vidyalaya New Cantt., Allahabad for his
encouragement and for all the facilities that he
provided for this project work. I sincerely
appreciate this magnanimity by taking me into
his fold for which I shall remain indebted to his. I
extend my hearty thanks to Mr. Ashok Kumar,
chemistry teacher, who guided me to the
successful completion of this project. I take this
opportunity to express my deep sense of
gratitude for her invaluable guidance, constant
4. encouragement, constructive comments,
sympathetic attitude and immense motivation,
which has sustained my efforts at all stages of
this project work. I can’t forget to offer my
sincere thanks to my family who helped me to
carry out this project work successfully & for
their valuable advice & support, which I received
from them time to time. A special thanks to my
friends to support me in every phase of my life.
8. Introduction
Freshmilk is sweetishintaste. However, whenit is kept for long time at a
temperatureof5degrees it becomesour becauseofbacteriapresent inair.
These bacteriaconvert lactoseofmilkinto lactic acid whichis sour in taste.
In acidic conditionCasein ofmilk starts separatingout as a precipitate.
Whenthe acidity in milkis sufficient and temperature is around36 degree, it
forms semi-solidmass, calledCURD. Casein is present inmilk as calcium
caseinate in the form of micelles. These micelles have anegative charge and
on adding acid to mik, the negative charges are neutrilised.
Milk is a completediet as it contains protein, carbohydrates, fats, minerals,
vitamins and water.
Average compositionof milkfrom different soruces is givenbelow:
9. Casein is the major proteinconstituent presentsinthe milk and is
mixedphospsor-protein.
Casein has isoelectric pHofabout 4.7 and canbe easily separated
around this pH.
Casein readily dissolve in acids and alkalies.
Theory
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 the body of an organism. The
major milk protein casein is found only in milk and
nowhere in the world. The composition of casein is not
constant and depends upon the source of milk.
10. Casein is the name for a family of
related phosphoproteins . These proteins are commonly
found in mammalian milk, making up 80% of the proteins
in cow's milk and between 20% and 45% of the proteins
in human milk. Casein has a wide variety of uses, from
being a major component of cheese, to use as a food
additive, to a binder for safety matches. As a food source,
casein supplies amino acids,carbohydrates, and the two
inorganic elements calcium and phosphorus.
Ca+2 (Casemated) + 2CH3 COOH(aq) Casein(s)+(CH3COO)2 Ca (aq)
11. requirements
Beakers(250 ml)
Filtration Flasks
Measuring Cylinders
Glass rod
Spatula
China Dish
Dropper
Weight Bore
Different samples of Milk
10% Acetic Acid
12. 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.
13. The milky solution was heated to
about 40 degree C and add 10%
acetic acidsolution 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.
