we LI EVERWIN VIDHYASHRAM SENIOR SECONDAY SCHOOL, MATHUR, CHENNAI-68 CHEMISTRY INVESTIGATORY PROJECT TO STUDY THE AMOUNT OF CASEIM IN DIFFERENT MILK ACADEMIC YEAR 2024-2025 NAME: MADESH.J CLASS: XII CLEVER CBSE ROLL :CERTIFICATE This is to certify that "J. MADESH" of "XII CLEVER has Successfull completed the chemistry Investigatory project “TO STUDY THE AMOUNT OF CASEIN IN DIFERENT MILK “under the guidance of “Mrs J. JENIFER AROCKIA MARY” and submitted for the practical examination conducted by the CBSE board during the year 2024 - 2025 INTERNAL EXAMINER EXTERNAL EXAMINERACKNOWLEDGEMENT lam grateful to my Chemistry teacher "Mrs. J.JENIFER AROCKIA MARY" and my principal "Mrs.M. ISHWARIYA " who gave the opportunity to perform this experiment and | would also like to show my gratitude towards her for moral support and for guiding me in many matters regarding the topic too. She been very kind and patient while telling me the outlines for this experiment and correcting my doubts. | thank her for her overall support. Also, | am highly thankful to my parents, for the kind support extended by them. Lastly, | would like to thank my group members and friends who helped me a lot in gathering different information, collecting samples of various fertilizers and participating equally in performing the tests involved.INTRODUCTION — Milk is a complete diet as it contains proteins, carbohydrates, fats, minerals, vitamins and water. The average composition of milk from different sources is given below: SOURCE OF | WATER MINERALS | PROTEINS FATS CARBO-HYDRATES: Ms ® ® |@ @) ®) cow 874 07 34 39 49 Human 87.4 Toa 14 40 49 Goat | 87 0.7 33, 42 48 Sheep | 82.6 0.9 55 65 45 Casein is the most predominant phosphoprote is found in milk an cheese. When coagulated with rennet, casein is sometimes called Paracasein. British terminology, on the other hand, uses the term caseinogen for the uncoagulated protein and casein for coagulated protein. As it exists in milk, it is a salt of calcium. Casein is not coagulated by heat. It is precipitated by acids and by rennet enzymes, a proteolytic enzyme typically obtained from the stomachs of calves. The enzyme trypsin can hydrolyze off a phosphate-containing peptone.Casein consists of a fairly high number of praline peptides, which do not interact. There are also no disulphide bridges. As a result, it has relatively little secondary structure or tertiary structure. Because of this, it cannot denature. It is relatively hydrophobic, making it poorly soluble in water. It is found in milk as a suspension of particles called casein micelles which show some resemblance with surfactant-type micellae in a sense that the hydrophilic parts reside at the surface. The caseins in the micelles are held together by calcium ions and hydrophobic interactions. These micelles have negative charge and on adding acid to milk the negative charges are neutralized. Ca” - Caesinate + 2CH,COOH(aq) > Casein+(CH,COO),Ca(aq) The isoelectric point of casein is 4.7. 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 sodium oxalate and sodium acetate.Applications: In addition to being consumed in milk, casein in used in the manufacture of adhesives, binders, protective coatings, plastics (such as for knife handles and knitting needles), fabrics, food additives and many other products. It is commonly used by bodybuilders as a slow-digestive source of amino acids as opposed to the fast-digesting whey protein, and also as an extremely high source of glutamine (post workout). Another reason it is used in bodybuilding, is because of its anti-catabolic effect, meaning that casein consumption inhibits protein breakdown in the body. Casein is frequently found in otherwise nondairy cheese substitutes to improve consistency especially when melted.THEORY —APPARATUS REQUIRED — Funnel, funnel stand , glass rod, filter paper, weight box , test tubes, pestle and mortar. CHEMICALS REQUIRED — (i) Different samples of milk. (ii) Saturated ammonium sulphate solution. (iii) 1% acetic acid solution.PROCEDURE — 1, Wash the beaker (250 ml) with the distilled water and dry it. 2. Take 20 ml of buffalo’s milk in 250 ml beaker and find its weight. 3. Add 20 ml saturated solution of ammonium sulphate slowly with stirring. Fat and casein will separate out as precipitate. 4. Filter the above solution and transfer the precipitate in another beaker. 5. Treat the above precipitate with 30 ml distilled water. Casein dissolves forming milky solution whereas fat remains as such. 6. Warm the above contents of the beaker to 40 - 45°C ona low flame. Now, add 1% acetic acid solution drop wise with stirring when casein gets precipitated. 7. Filter the precipitated casein and wash with distilled water and dry it. 8. Find the weight of dry precipitate. 9. Repeat the whole experiment with cow’s milk, goat’s milk and sheep’s milk.OBSERVATIONS — Volume of milk taken in each case = 20 ml Weight of milk taken = W, g Weight of Casein isolated = W, g Percentage of casein = Weight of Casein x 100 Weight of milk ore een S.no. | Type of milk | Volume of | Weight | Weight of | Percentage of milk taken | of milk Casein casein (ml) (Wig) | (Wig) t Buffalo’s 20 23.09 0.632 2.73% milk 2. | Cow's milk | 20 35.66 | 0.55 | 1.64% 3. | Goat’s milk | 20 23.09 | 0.77 | 3.67%RESULT — Different Samples of milk contains different percentage of casein. Highest percentage of casein is present in Goat's milk. PRECAUTIONS — 1. Handle apparatus and chemicals carefully. 2. Add ammonium sulphate solution very slowly. 3. Stir milk while adding chemicals. 4.Do not disturb milk after adding ammonium sulphate solution and wait some time for fat and casein to precipitate out. 5. Take the amount readings carefully with digital weighing machine only.BIBLIOGRAPHY — www.wikipedia.com www.encyclopedia.com www.caesine-pro.com www.sciencejournals.com www.zetascience.com www.scribd.com www.icar.nic.inThank You