study of milk casein chemistry class 12

1. welcome to my INVESTIGATORY project
Name: Samrat Singharoy
Class:12
Roll no.:27
Subject: Chemistry

2. Study of quantity of casein present in different samples of
Milk.

3. CERTIFICATE
This is to certify that Mas. Samrat Singha Roy of K.V.
G.C. C.R.P.F school, Agartala has completed his project of
Chemistry under my Guidance. He has taken proper care and
shown at most Sincerity in completion of this project. I certify
that Project is up to my expectation and as proper guideline
issued by C.B.S.E.
Date
Signature

4. Acnoledgement
I would like to take this opportunity to express my deep sense of gratitude to my
heartiest and dedicated teacher Mrs. Samarpreet Nayyar mam and our most honourable
principal Mr. Pawan Kumar Sir, who has provided me their valuable time and information.
This project would not have been possible without their kind support and guidance.
Their continuous support, encouragement and patience have greatly eased my burden
and made this project work a success.
It was a great opportunity for me to work in 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 cooperation during the entire tenure of this
project. I would also like to thank my guardian for their inexhaustible source of inspiration
and moral support. Last but not the least, the guidance and supervision of all those who helped
me in making this project were very helpful in bringing this work to a conclusion.
With Warm Regards,
Samrat Singharoy, Class 12

5. preface
The main objective of science is to get as much practical knowledge as possible. Being able to have practical
knowledge by developing a project is a lifetime Experience . Practical knowledge is as important as theoretical
knowledge .we are very pleased by having such a practical project.
In developing this we have to overcome various difficulties . and these difficulties lead to a great experience of
various subjects. which will surely help us in the upcoming future in building our personality.
I am pleased to present this project, Proper care had been taken intriguing this project that it is to comprehend.
And also some scientific concepts have been implemented in making this project.
Thus it is well said that "Everything is theoretically impossible until it is done"

6. History:
Drink to wear: The technology has benefited us in the way
by providing us the alternative to extract milk`s advantage
without actually drink it.
Milk`s potential for cloth: during the First world War, when the
Germans were looking out for some newer sources of fabric, it
was then they discovered milk`s potential for cloth.
How they Processed: The solutions of casein were spun
experimentally to form fibres and it was forced through the jets

7. Into hardening baths forming solid filaments in which the
long casein molecules had been given sufficient orientation
to hold together in typical fibre form.
Why Germans Failed?: These early fibre were of little value
. They were brittle, hard and lacked the resilience and
durability needed for textile use.

8. Different structures of casein

9. introduction
The casein in milk form complexes called micelles that are dispersed in water phase of
milk. The casein micelles consist of subunits of different caseins(a-s1,a-s2,B) held together
by calcium phosphate bridges on the inside, surrounded by a layer of K-casein which helps
to stabilize the micelles in solution
Casein micelles are spherical and are 0.04 to 0.3 um in diameter, much smaller than fat
globules. The casein micelles are porous structure that allow the water phase to move
freely in and out of the micelle. They can be heated to boiling or cooled, and they can they
can be dried and reconstituted without adverse effects. B-casein, along with some calcium
phosphate, will migrate in and out of the micelle with changes in temperature, but this
does not affect the nutritional properties of protein and minerals.

10. Casein synthesized in the secretory cells mammary gland.
Constitute 80% of total milk protein.
Present in the form colloidal suspension.
Casein linked with Ca forming Ca-Caseinate
Present in the form casein complex=casein micelles.
Ca-Caseinate linked with phosphate forming Ca caseinate -Ca phosphate complex or
Casein complex.
K. casein covering the casein micelle so act as stabilizing agent.
The buffalos casein micelle is larger than cow`s casein micelle.so it contains more
phosphate, and Ca.
Alpha and beta casein are water insoluble(hydrophobic) while, K-casein
soluble(hydrophobic)
K-casein composed of protruding chain hairy look (hydrophobic C-terminal)

11. Micelle composed of:
1. Ca- phosphate
2. Hydrophobic interaction between submicelles
3. Hydrophobic C-terminal part of K-casein containing carbohydrates
group project from the micelle giving them hairy look.
All are responsible for the stability and integrity of casein micelle. If
Ca leaves the micelle. If Ca leaves the micelles they will be
disintegrates into submicelles.
K-Casein is the site of attack by renin enzyme or rennet, the micelles
will lose their solubility and start to aggregates to form the curd.

13. Factors Affecting The Stability Of Casein Micelles
1 . PH : Decrease PH leads to Ca phosphate dissociation till reach the
reach the isoelectric point(PH=4.6)----then all phosphate are
dissolved and casein in ppt.
2. Salt : Affect on Ca-phosphate in micelles.
3. Temp: At 4c B-casein begin to dissociate form micelle.
At 0C there is no micellar aggregates
Freezing below zero degree---produce ppt(clots cryo-casein).
At heat ---the protein denaturants and alter micelle structure.
4. Dehydration: Casein micelle may be separated forming gelatinous
mass of the curd.

15. Casein uses:
1 - In Foods: used in binder in meat products
Used as ingredient in ice-cream
2 - Industrial used: used as a casein glue, textiles, casein plastics.
WAYS OF CASEIN PPT?
1-by adding of acids or souring (natural souring or direct addition of acid like
acetic acid or benzoic acid)----it will ppt to iso-electric point.
Ca caseinates Ca lactate (soluble)+casein(ppt),Principle of fermented
milks
2- Renin enzyme(rennet) → Ca caseinate(colloidal)→ Ca-para
caseinate(ppt).
3 -Addition of copper sulphate.

17. 4 - By addition of weak acids + alcohol.
5 - By addition of weak acid + heating at 65-75c.
6 - At 80-100c----denature the proteins which bind to casein micelle(K-casein).at
120-140c micelles aggregates forming a gel or ppt.
N.B: The basis for cheese manufacture is addition of renin enzyme which act on
K-casein (lass the stabilizing factor for casein micelle) ----So Kappa Casein become
free and in presence of Ca salt is ppt as clot or curd.
N.B: Psychotropics micro-organisms produce enzymes split K-casein.
It is obtained if casein ppt by any methods of ppt(rennet or acids) -----the
remaining solution called whey protein or milk serum protein
In fresh milk, whey proteins present in the form of colloidal solutions. They
differ than casein micelle which rich in phosphate group while, whey proteins rich
in sulfhydryl group.
Heating milk more than 80c------ formation of sulphate bridge between beta-
lactoglobulin and K-casein---- sulphurous compounds(cooked flavour)----also
sulphur bridge formed between whey proteins.

19. BLOOD SERUM PROTEINS—
1. Immunoglobin (PT in nature)
IgG1,IgG2,IgA,IgM,IgE Transferred from blood to udder Mainly present
in colostrum.
2 . Blood serum albumin
It synthesized in liver then transported to udder via blood. Increasing its
level indicates mastitis. Its level in cow`s milk 0.4g/l.
ENZYMES AND LACTOFERRIN
1. Proteases and peptone enzymes constitute 1-2% of total
milk protein.
2 .Is is called iron binding protein used in food preservation.

21. MEMBRANE PROTEINS: FAT GLOBULE MEMBRANE PROTEIN
It is the protective layer which surrounds the fat globule to stabilized
its emulsion form . Lipolytic enzyme are adsorbed on the membrane
structure there is no reaction once the membrane is intact .When it
broken enzymatic reaction occurs and liberation of fatty acids and
rancid flavour.
N.B: Fat globule membrane broken in case of severe agitation and
homogenization.
NON-PROTEIN NITROGENOUS COMPOUNDS:
Like ammonia, urea, uric acid, creatine, creatinine.

22. INFLUENCE OF HEAT TREATMENT ON MILK PROTEINS
The caseins are stable to heat treatment. Typical high temperature short
time(HTST) pasteurization conditions will not affect the functional and
nutritional properties of casein proteins.
High temperature treatments can cause interactions between casein and
whey proteins that affect the functional but not the nutritional properties.
For example, at high temperatures, B-lactoglobulin can form a layer over the
casein micelle that prevents curd formation in cheese.
The whey proteins are more sensitive to heat than the caseins. HTST
pasteurization will not affect the nutritional and functional properties of the
whey proteins. Higher heat treatments may cause denaturation of B-
lactoglobulin, which is an advantage in the production of some foods(yogurt)
and ingredients because of the ability of the proteins to bind more water.

23. Denaturing causes a change in the physical structure of proteins, but
generally does not affect the amino acid composition and thus the
nutritional properties. Severe heat treatments such as ultrahigh
pasteurization may cause some damage to heat sensitive amino acids
and slightly decrease the nutritional content of milk. The whey protein
A-lactalbumin, however, is very heat stable.

25. AIM:
To study the quantity of casein in different samples of Milk.
Requirements:
1. Beakers(205ml)
2. Filter paper
3. Glass rod
4. Weight box
5. Filtration flask
6. Buchner funnel
7. Test tubes
8.procelain

26. 9. Different samples of milk.
10. 1% of acetic acid solution.
11. Ammonium sulphate solution

27. THEORY
Natural milk is an opaque white fluid secreted by the
mammary glands of female mammal.
The main constituents of natural milk are proteins,
Carbohydrates, 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 become sour because of bacteria present in air.
These bacteria convert lactose of milk into lactic acid which
is sour in taste.

28. 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.

29. procedure
1. Take 200ml of each sample of milk in separate
beakers(500ml)
2. Heat the beakers containing milk samples up-to
50-60`C.
3. Now , add acetic acid ,Casein coagulates as
amorphous substance.
4. After adding acetic acid , Casein coagulates as
amorphous substance.

30. 5-Filter the precipitates with the help of the funnel
and wash the precipitates several times with tap
water.
6-Remove the fat by using a suitable organic solvent
like alcohol.
7-Now ,wash the Casein again with water and dry it.
8-Weight a dried casein in a watch glass.
9-Repeat this process with all samples of milk.

31. Observations:
THE Volume of milk taken in each case=200 ml
SAMPLE
NO.
SOURCE CONTENTS OF
PROTEIN
AMOUNT O
CASEIN(G/ML)
% OF
CASEIN
1. COW MILK 0.60g 0.5 5
2. GOAT MILK 0.65g 0.34 3.24
3. BUFFALO
MILK
0.85g 0.4 4.20

32. RESULT and conclusion:
According to our analysis of various samples of milk, we
conclude that:
Cow milk contains 5 % casein.
Goat milk contains 3.25% casein.
Buffalo milk contains 4.2% casein.
According to above results, we conclude that Cow`s
milk is most beneficial for human beings

33. Precautions:
– During filtration , press the casein formed.
– Use only the required amount of acid for
complete precipitation.
– Use only fresh milk.
– Use same amount of each sample for the
experiment.