Bio Project On Casein Content in Milk

To determine quantity of Casein in different
samples of milk
Submitted by:
Sheen Razdan
XII A
ACKNOWLEDGEMENT
I would like to express my profound and heartfelt gratitude

towards all those who have helped me in making this project. Without
their able guidance, support, cooperation and encouragement this project
would not have been completed on time.
I extend my gratitude to Director Principal Dr. Amrita Vohra and

Principal Senior Secondary Ms. Sandra Cheema for providing the
facilities and moral support extended during the tenure of the project.
I would also like to thank our chemistry teacher, Aarti Mishra for
her guidance, support and encouragement throughout the duration of the
project. Without her constant motivation and help the successful
completion of this project would not have been possible.
I’m thankful to Lab assistance, Vasant Sir for their timely help.
I also acknowledge with deep sense of reverence towards my parents

and other faculty members of the school. I’m sincerely thankful to my
friends for their valuable suggestions given time to time.
BIOLOGY INVESTIGATORY PROJECT
SR. NO. CONTENT PAGE NO.

1 INTRODUCTION 1-5
2 AIM 6
3 MATERIALS 6
4 PROCEDURE 7
5 OBSERVATION 8
6 RESULT 8
7 PRECAUTIONS 9
8 BIBLIOGRAPHY 9
INTRODUCTION
Milk
Milk is a nutrient rich, primary source of nutrition for infant mammals
(including humans), before they are able to digest other types of food. It
is produced by the mammary glands of mammals. Early lactation milk
contains colostrum which carries the mother’s antibodies and many their
nutrients including lactose and proteins. Inter species consumption of
milk is not uncommon, particularly among humans, many of whom
consume the milk of other mammals. Considerable acclaimed health
benefits of milk are related to its proteins, not only for their nutritive
value but also for their biological properties. Scientific evidence
suggests that anticarcinogenic activities, antihypertensive properties,
immune system modulation, and other metabolic features of milk, are
affiliated with its proteins.
Milk is also good for the bones because it offers a rich source of
calcium, a mineral essential for healthy bones and teeth. Cow's milk is
fortified with vitamin D, which also benefits bone health. Calcium
and vitamin D help prevent osteoporosis.
As an agricultural product, milk is extracted from farm animals. Dairy
farms in India produced an estimated 176.35 million tons during the last
financial year. India is the world’s largest producer of milk and the
leading exporter of skimmed milk powder. The US, India, China and
Brazil are the world’s largest exporters of milk and milk products.
Throughout the world, more than 6 billion people consume milk
products. Over 750 million people live in dairy farming households.
Milk as a whole contains water, vitamins –A, D and K, fats,
carbohydrates, proteins, and minerals such as calcium, sodium,
potassium and trace metals. The proportion of these varies from source
to source.
Here is the average composition of milk from different sources-
ANIMALS Water Proteins Casein Whey. Fat. Lactose Ash.

% % % % % % %
Human 87.5 1 0.5 0.5 4.5 7.1 0.2
Buffalo 83.84 4 3.5 0.5 6.1 4.8 0.8
Cow 86.87 3.5 2.8 0.7 3.7 4.8 0.7
Goat 86.5 3.6 2.7 0.9 4 4.7 0.8
Sheep 82 4.6 3.9 0.7 7.2 5 0.8-
0.9
Camel 86.5 3.6 2.7 0.9 4 6.2 0.5
Casein –
Casein (from Latin –caseus “cheese”) is a mixture of phosphoproteins of
differing molecular weights. These proteins are commonly found in
mammalian milk, comprising 80% of the proteins in cow’s milk and
20% - 45% in human milk.
It is the chief protein in milk in pure form. it is an amorphous white
solid, tasteless and odourless while its commercial type is yellowish with
a pleasing odour. Cow’s milk contains 3% casein.
Casein has anticarcinogenic activities and protects the body against
colon cancer, decreases the incidence of chemical induced intestinal
tumors and reduces activity of plaque promoting enzymes. It also shows
Hypocholesterolemic effects by reducing the total cholesterol, LDL-C,
HDL-C and lipoprotein concentrations.
Casein is used in prepared foods in medicines and dietary supplements
and in cosmetics. Minor industrial applications include the seasoning
and dressing of leather, cleaners and polishes for shoes, textiles printing
and sizing, insecticides sprays, soap making and many uses in which
casein serves as a protective colloid emulsifying agent or binder. Major
applications for casein are paper, coatings, glues paints plastics and man
made fibers.
Casein is a lyophilic colloid akin to albumin and gelatin. It is isoelectric
at ph 4.6, and its solubility in water is only 0.01%.
It is amphoteric: below ph 4.6, casein forms moderately soluble salts
such as casein chloride; above ph 4.6 casein forms salts with bases.
Sodium caseinate and other alkali salts are insoluble without limit, while
calcium caseinate, other alkaline earth salts and heavy metal salts are
nearly insoluble. Caseinates readily form gels when slowly coagulated
from concentrated solutions. Formaldehyde forms an insoluble
compound with casein. It is insoluble in most organic solvents.
Casein has a relatively tertiary structure. It is hydrophobic making it
poorly soluble in water.
The structure of Casein-
Amino acid profiling-
For the separation of Casein and whey proteins, milk samples were
centrifuged by centrifugation at 5000g for 15 minutes at 4 degree
Celsius. The skimmed milk heated to 37 degree Celsius was separated
into Whole casein and whey proteins by isoelectric precipitations at ph
4.6 with 1N HCl. After centrifugation at 5000g for 15 minutes at 30C,
the supernatant was collected and dialyzed at 4 degree Celsius. Against
several changes of distilled water, while the precipitated caseins were
washed with acidified distilled water. Both fractions were then freeze
dried for further analysis.
Amino Acid Analysis-

The freeze dried samples of casein and weigh protein were then
subjected to determination of amino acid’s composition using an amino
acid analyzer. These samples were hydrolyzed with 6N HCL, under
vacuum at 110C for 24 hours. Excess acid was removed by drying the
hydrolysates in a rotary evaporator at 49C under vacuum. To obtain a
clean solution of the hydrolysate, the dry residues were dissolved in a
known quantity of citrate buffer of pH 2.2 and filtered.
AIM
To determine the quantity of casein in different samples of milk.
MATERIALS
Conical flask
• Beakers
• Funnel
• Measuring cylinder (100 mL) • Watch glass
• Filter paper
• 1% acetic acid
• Different samples of milk • Glass rod
PROCEDURE
1) Take 200 mL of each sample of milk in separate beakers (500 mL).
2) Heat the beakers containing milk sample up to 50- 60oC.
3) Now, add a few drops of 1% acetic acid solution slowly with

constant stirring with a glass rod for 5-10 minutes.
4) After adding acetic acid, casein coagulates as amorphous

substance.
5) Filter the precipitate 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) Weigh dried casein in a watch glass.
9) Repeat this process with all samples of milk. Take 200 mL of each
sample of milk in separate beakers (500 mL).
OBSERVATION
Volume of each milk sample is 20 ml
SAMPLE SOURCE VOLUME WEIGHT % OF

NO. OF MILK CASEIN CASEIN
(ml) (g)
1 Chitale 20ml 0.62 3.1%
2 Patanjali 20ml 0.60 3.0%
3 Amul 20ml 0.38 3.88%
4 Buffallo 20ml 0.63 2.73%
RESULT
According to our analysis of various samples of milk, we conclude that:

Chitale milk contains: 3.1 % casein.
Patanjali milk contains: 3.0% % casein.
Buffalo milk contains: 2.73% casein
Amul milk contains: 3.88% casein.
According to above results, we conclude that Amul milk- Cow’s milk is
most beneficial for human beings.
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.
BIBLIOGRAPHY
1. Kunz et. al, "Human-milk proteins: analysis of casein and casein subunits by
anion-exchange chromatography, gel electrophoresis, and specific staining
methods". Am. J. Clin. Nutr. 51 (1): 37–
46. doi:10.1093/ajcn/51.1.37. PMID 1688683
2. "Industrial Casein". National Casein Company. Archived from the
original on 12 November 2012.
3. "Casein". The Columbia Electronic Encyclopedia (6th ed.). Columbia
University. 2011
4. El-Bakry et. al, "Functional and Physicochemical Properties of Casein and
its Use in Food and Non-Food Industrial Applications". Chemical Physics
Research Journal. 4: 125–138 – via ProQuest.

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To determine quantity of Casein in different

I would like to express my profound and heartfelt gratitude

I extend my gratitude to Director Principal Dr. Amrita Vohra and

I also acknowledge with deep sense of reverence towards my parents

SR. NO. CONTENT PAGE NO.

Here is the average composition of milk from different sources-

ANIMALS Water Proteins Casein Whey. Fat. Lactose Ash.

Amino Acid Analysis-

To determine the quantity of casein in different samples of milk.

1) Take 200 mL of each sample of milk in separate beakers (500 mL).

2) Heat the beakers containing milk sample up to 50- 60oC.

3) Now, add a few drops of 1% acetic acid solution slowly with

4) After adding acetic acid, casein coagulates as amorphous

6) Remove the fat by using a suitable organic solvent like alcohol.

Volume of each milk sample is 20 ml

SAMPLE SOURCE VOLUME WEIGHT % OF

According to our analysis of various samples of milk, we conclude that:

 During filtration, press the casein formed.

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