Separation of Casein from Milk

697 Words3 Pages
I. Title: Date: November 8, 2012 Name: Di Jin Section:Thursday II. Purpose: To isolate the protein casein from a sample of milk and to calculate the percentage of casein in milk, which is the purpose of this experiment. III. Materials & equipment: - Milk - Water - 30 mL 95% ethanol - 15 drops Glacial acetic acid - 100 mL Graduated cylinder - 125 mL Erlenmeyer flask - Bakers (50 mL and 400 mL) - Electronic balance - Thermometer - Paper cups - Cheese cloth - Rubber band - Buchner filtering apparatus: ring stand, utility clamp, filter paper, vacuum flask, buchner funnel, rubber hose, neoprene adapters(one small and one large). - Heating apparatus: Bunsen burner, ring stand, ring support, wire gauze, burette clamp IV. Procedure: Weigh a flask on an electronic balance. Record data. Using a 100 mL graduated cylinder, measure 80 mL milk, then pour the 80 mL milk into the flask and weigh it again. Record data. 2. Set up the heating apparatus: A ring stand is positioned a few inches higher on the stand from the bunsen burner which is placed at the base of the ring stand. The wire gauze is placed on the ring support. Clamping the thermometer above the beaker by using a burette clamp. 3. Using the distilled water to fill 1/3 of a 400 mL beaker. Put the flask with milk in the beaker which is filled with water, and place it on the wire gauze. Put the thermometer into the milk(under the milk). Turn on the Bunsen burner and warm the milk reach to 50~60 degrees Celsius. 4. The milk was taken out from the water, then 15~20 drops glacial acetic acid were added. The milk was stirred with a stirring rod (every five drops were observed) until a white solid has formed. 5. Put cheesecloth on the top of 50 mL beaker, also using a rubberband to tie it. Separating the liquid and solid when the mixture was poured
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