investigatory project casein Chemistry final

This is my investigatory class 12 chemistry project on the topic "study of quantity of casein present in various milk samples"

1. CHEMISTRY PROJECT STUDY OF QUANTITY OF CASEIN PRESENT IN DIFFERENT SAMPLES OF MILK BY PALLAVI SARIN CLASS: SUBJECT: CHEMISTRY SESSION: SCHOOL: ROLL NO.

2. CERTIFICATE This is to certify that XXXX XXXX of class XXX , XXXXX School, XXXXXX has successfully completed the investigatory project titled “ STUDY OF QUANTITY OF CASEIN PRESENT IN DIFFERENT SAMPLES OF MILK ” under the guidance and supervision of Ms. XXXXX XXXXX (Chemistry Teacher) during the year 2XXX-2XXX in the partial fulfillment of the Chemistry practical examination conducted by the CBSE. It is further certified that this project is the individual and bonafide work of the candidate . This project in my opinion is completed and ready for presentation. EXTERNAL EXAMINER SUBJECT TEACHER (Ms. XXXXX XXXXX )

3. ACKNOWLEDGEMENT I  would like to express my special thanks of gratitude to my teacher Ms. XXXXXX XXXXXX as well as our principal Ms . XXXX XXXX who gave me the golden opportunity to do this wonderful project on the topic “ STUDY OF QUANTITY OF CASEIN PRESENT IN DIFFERENT SAMPLES OF MILK ”, which also helped me in gaining knowledge about the topic and in learning new things. I take this opportunity to express my deep sense of gratitude for her invaluable guidance, constant encouragement, constructive comments, sympathetic attitude and immense motivation, which has sustained my efforts at all stages of this project work. I am really thankful to them . Secondly I would also like to thank my parents and friends who encouraged me and supported me to do the project to the best of my ability.

4. INDEX AIM APPARATUS AND CHEMICALS REQUIRED PRINCIPLES APPLIED AND THEORY PROCEDURE OBSERVATION RESULT PRECAUTIONS BIBLIOGRAPHY

5. AIM TO STUDY THE QUANTITY OF CASEIN PRESENT IN DIFFERENT SAMPLES OF MILK.

6. APPARATUS AND CHEMICALS REQUIRED APPARATUS 250ML BEAKERS FUNNEL, GLASS ROD PORCELAIN DISH CHEMICAL BALANCES TEST TUBES FILTRATION FLASK BURNER CHEMICALS DIFFERENT SAMPLES OF MILK 1% OF ACETIC ACID SOLUTION SATURATED AMMONIUM SULPHATE SOLUTION

7. THEORY Casein is the name of related phosphoproteins . These proteins are commonly found in mammalian milk, making up 80% of the proteins in cow 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. The most common form of casein is sodium caseinate . As a food source , casein supplies for amino acids, carbohydrates and two inorganic elements, calcium and phosphorus . Casein contains a fairly high number of proline residues, which do not interact. There are also no disulfide bridges. As a result hydrophobic, making it poorly soluble in water. It is found in milk as a suspension of particle called “casein micelles” which show only limited resemblance with surfactant-type micelles in a sense that the hydrophilic parts reside at the surface and they are spherical. However, in sharp contrast to surfactant micelles, the interior of a casein micelle is highly hydrated.

8. The caseins in the micelles are held together by calcium ions and hydrophobic interactions. Several models account for the special conformation of casein in the micelles. One of them proposes the micellar nucleus is formed by several sub micelles, the periphery consisting of K-casein . Another model suggests the nucleus is formed by casein-interlinked fibrils. Finally, the most recent model proposes a double link among the caseins for gelling to take place. All three models consider micelles as colloidal particles formed by casein aggregates wrapped up in soluble K-casein molecules.

9. Finally , the most recent model proposes a double link among the caseins for gelling to take place. All three models consider micelles as colloidal particles formed by casein aggregates wrapped up in soluble κ-casein molecules.

10. Since milk's pH is 6.6, casein has a negative charge in milk. The purified protein is water-insoluble. While it is also insoluble in neutral salt solutions, it is readily dispersible in dilute alkalis and in salt solutions such as aqueous sodium oxalate and sodium acetate. The enzyme trypsin can hydrolyze a phosphate- containingpeptone . It is used to form a type of organic adhesive. Ca 2+- Caseinate + 2CH 3 COOH(aq. )----  Casein(s)+ (CH 3 COOH) 2 Ca

11. Milk is a nutrient-rich, white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for infant mammals (including humans who are breastfed ) before they are able to digest other types of food . Early-lactation milk contains colostrum, 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. Interspecies consumption of milk is not uncommon, particularly among humans, many of whom consume the milk of other mammals. As an agricultural product, milk, also called dairy milk, is extracted from farm animals during or soon after pregnancy . Dairy farms produced about 730 million tonnes 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.

12. 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. Throughout the world, more than six billion people consume milk and milk products. Over 750 million people live in dairy farming households. Milk as a whole contains water, minerals ( Ca, K, Na and trace metals), vitamins(A, D, K ), carbohydrates , proteins and fats. The proportion of these varies from source to source. Average composition of milk from different sources is given ahead.

13. SEPARATION OF CASEIN Natural milk is an opaque white fluid secreted by the mammary glands of female mammal. 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.

14. PROCEDURE 1. 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 slowly and with stirring. Fat along with casein was precipitate out. 2. The solution was filtered and transferred the precipitates in another beaker. Added about 30 ml of water to the precipitate. Only casein dis solves in water forming milky solution leaving fat undissolved. 3. The milky solution was heated to about 40° C and 1% acetic acid solution drop-wise, when casein got preci pitated . 4. Filtered the precipitate, washed with water and the precipitate was al lowed to dry. 5. Weighed the dry solid mass in a previously weighed watch glass . 6. The experiment was repeated with other samples of milk.

15. OBSERVATION TABLE S.NO. TYPE OF MILK WEIGHT OF CASEIN PRESENT PERCENTAGE OF CASEIN (i.e. g/100ml) 1. COW MILK 0.60 3.00% 2. GOAT MILK 0.55 2.75% 3. BUFFALO MILK 0.85 4.25% 4. AMUL MILK 0.75 3.75% Volume of each milk sample is 20 mL.

16. RESULT According to our analysis of various samples of milk, we conclude that: Cow milk contains 3.00 % casein Goat milk contains 2.75 % casein Buffalo milk contains 4.25 % casein Amul milk contains 3.75 % casein According to above results, we conclude that buffalo milk is most beneficial for human beings.

17. 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.

18. BIBLIOGRAPHY Google Images NCERT Chemistry Laboratory Manual Class XII www.chemistrystackexchange.com/ https://en.wikipedia.org/wiki/Casein https://en.wikipedia.org/wiki/Milk https:// www.slideshare.net/dineshpol/amount-of-casein-in-milk