Guide Questions: 1. What is the resulting color for this test? Brick.red erecinitata 2. What carbohydrate is present in milk? Beducina disaccharide - Lactoss C4. Test for Phosphate a To another 1 mL of the fitrate, add 1 ml of ammonium molybdate. b. Observe the formation of the precipitate. Guide Questions: 1. What is the color of the precipitate formed? 2 What are the chemical name and the chemical formula for the precipitate formed? Ammonium Phosehomolvhdate - INHPO:12Mo0 CS. Test for Chlorides a To 1 ml of the filtrate, add 5 drops of silver nitrate solution. Guide Question: 1. Does milk contain chlorides? C6. Test for Calcium a To another 1 ml of the fitrate, add 5 drops of potassium oxalate solution. Guide Questions: 1. What is the color of the precipitate? 2. What is the chemical name and formula for the precipitate formed? C7. Test for Sulfates a To another 1 ml of the filtrate, add 5 drops of barium chloride solution. Observation: Summary of Results (Constituents of Milk) Results Test/Reagents Color Formula of the () result Biuret test Benedicf's test Phosphate Chlorides Calcium

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Experiment 6- Milk
Objective: 1. Identify the different physical properties of milk.
2. Determine the different constituents of milk.
Apparatuses: test tubes, test tube rack, test tube holder, tripod, wire gauze, graduated
cylinder, dropper, beaker, watch glass
Materials: evaporated milk, litmus paper, filter paper, dilute NaOH solution, Cuso,
solution, acetic acid, Benedict's solution, ammonium molybdate solution,
AGNO, solution, BaCi, solufion, KCo, solution
Mik is an emulsion of fat globules and suspension of casein micelles (Ca,
casein, P), all of which are suspended in an aqueous solution.
Mik is the only single food that possesses many nutritional values. However, it
still cannot be considered as a complete single food because it lacks iron and copper,
among other essential nutrients. The proteins are caseins (about 80%), lactalbumin,
and lactoglobulin. The fat contains fatty acids ranging from C, to C Other lipids include
cholesterol and phospholipids. Lactose constitutes the principal carbohydrate. Minerals
and vitamins in varying amounts make up the rest of the nutritional make-up.
Mik fat is believed to have its origin in the phospholipids of the blood. The
lactose of milk is derived from the glucose of the blood. The inorganic salts, ike
calcium, magnesium, sodium, phosphates, citrates, chlorides, and other inorganic
constituents are likewise derived from the blood, some by a simple process of filtration.
The bone acts as a reserve supply of calcium.
Human milk differs from cow's milk in having less casein and ash and more
albumin and lactose.
Mik is a nutritious, cost-efficient source of protein, minerals, and vitamins. Milk
naturally provides more than ten essential nutrients in one tasty, convenient, and
affordable package.
Mik contains calcium, Vit. A, Vit. B12, iodine, riboflavin, potassium, magnesium,
zinc, phosphorus, carbohydrate, and high-quality protein. These days new beneficial
components of milk are being discovered, such as whey protein, sphingomyelin, and
conjugated linoleic acid.
A. Physical Properties
1. Indicator test: Test the reaction of both fresh and sour milk with red and blue
litmus paper.
Red Litmus
Red litmus paper
Milk
Blue litmus
Fresh
Blue litmus paper turns
remains red
red
Sour
Red litmus paper
Blue litmus paper turns
remains red
red
2. Formation and Composition of Film from Milk
a. Place 10 mL of fresh milk in an evaporating dish.
b. Boil and observe the formation of a fim.
Observation: It formed a skin on the surface, which was driod out
by evaporation. The sticky film produced is knnwn as lactndem
c. Remove the fim and then boil again.
Observation: Lass condensed film wan formed,
d. Test the film with Biuret's test and the Acrolein test.
Result with Milk Film
Substance present
Proteins
Test Performed
Biuret's test
Violet color
Acrolein test
Brown stain on the filter Glycerol and triglycerides
раper
Burnt fat odor
e. Get 10 mL fresh milk, then acidify it with acetic acid, and repeat the above
experiment.
Guide Questions:
1. What can you conclude regarding the chemical composition of the film formed?
Mik contains proteins such as lactoglobulin and casein. After boiling, these
proteins are denatured and coagulated with miks fat, forming a skin on the
Furface, then dried cut by evanoration. The stickv film of proteins formed is called
alastoderm.
2. Did you get a film on boiling sour milk?
Yes. In sour milk. the lactosn present in the milk is oxidized with the hele of
bacteria into Lartic Acid, which will acidify the solution: thus, leading to protein
danaturation. Therefore, on heating sour milk. skin formation on milk wil be
increased.
3. Explain the mechanism involved in the formation of the fim.
The fim. which is also knawn as mik skin. is formed due to fatuorotain
interaction. On boiling milk, the water present at the surface will evaporate,
thereby leading to exposure of the fats and proteins molecules which bind and
thus, form milk fim.
B. Curdling of Milk
This refers to the precipitation of milk proteins, especially casein. In infants,
the enzyme rennin helps to bring about curdling. This makes the milk easier to
digest. However, in adults, HCI and pepsin (there is no rennin) are responsible for
curding whatever mik adults take in their diet.
Mik is converted into curd or yogurt by the process of fermentation. Milk
consists of globular proteins called casein. The curd foms because of the chemical
reaction between the lactic acid bacteria and casein. During fermentation, the
bacteria use enzymes to produce energy (ATP) from lactose. The byproduct of ATP
production is lactic acid. Lactic acid acts on globular proteins present in the milk and
denatures them. This denaturation destroys the tertiary and quaternary structures of
Transcribed Image Text:Experiment 6- Milk Objective: 1. Identify the different physical properties of milk. 2. Determine the different constituents of milk. Apparatuses: test tubes, test tube rack, test tube holder, tripod, wire gauze, graduated cylinder, dropper, beaker, watch glass Materials: evaporated milk, litmus paper, filter paper, dilute NaOH solution, Cuso, solution, acetic acid, Benedict's solution, ammonium molybdate solution, AGNO, solution, BaCi, solufion, KCo, solution Mik is an emulsion of fat globules and suspension of casein micelles (Ca, casein, P), all of which are suspended in an aqueous solution. Mik is the only single food that possesses many nutritional values. However, it still cannot be considered as a complete single food because it lacks iron and copper, among other essential nutrients. The proteins are caseins (about 80%), lactalbumin, and lactoglobulin. The fat contains fatty acids ranging from C, to C Other lipids include cholesterol and phospholipids. Lactose constitutes the principal carbohydrate. Minerals and vitamins in varying amounts make up the rest of the nutritional make-up. Mik fat is believed to have its origin in the phospholipids of the blood. The lactose of milk is derived from the glucose of the blood. The inorganic salts, ike calcium, magnesium, sodium, phosphates, citrates, chlorides, and other inorganic constituents are likewise derived from the blood, some by a simple process of filtration. The bone acts as a reserve supply of calcium. Human milk differs from cow's milk in having less casein and ash and more albumin and lactose. Mik is a nutritious, cost-efficient source of protein, minerals, and vitamins. Milk naturally provides more than ten essential nutrients in one tasty, convenient, and affordable package. Mik contains calcium, Vit. A, Vit. B12, iodine, riboflavin, potassium, magnesium, zinc, phosphorus, carbohydrate, and high-quality protein. These days new beneficial components of milk are being discovered, such as whey protein, sphingomyelin, and conjugated linoleic acid. A. Physical Properties 1. Indicator test: Test the reaction of both fresh and sour milk with red and blue litmus paper. Red Litmus Red litmus paper Milk Blue litmus Fresh Blue litmus paper turns remains red red Sour Red litmus paper Blue litmus paper turns remains red red 2. Formation and Composition of Film from Milk a. Place 10 mL of fresh milk in an evaporating dish. b. Boil and observe the formation of a fim. Observation: It formed a skin on the surface, which was driod out by evaporation. The sticky film produced is knnwn as lactndem c. Remove the fim and then boil again. Observation: Lass condensed film wan formed, d. Test the film with Biuret's test and the Acrolein test. Result with Milk Film Substance present Proteins Test Performed Biuret's test Violet color Acrolein test Brown stain on the filter Glycerol and triglycerides раper Burnt fat odor e. Get 10 mL fresh milk, then acidify it with acetic acid, and repeat the above experiment. Guide Questions: 1. What can you conclude regarding the chemical composition of the film formed? Mik contains proteins such as lactoglobulin and casein. After boiling, these proteins are denatured and coagulated with miks fat, forming a skin on the Furface, then dried cut by evanoration. The stickv film of proteins formed is called alastoderm. 2. Did you get a film on boiling sour milk? Yes. In sour milk. the lactosn present in the milk is oxidized with the hele of bacteria into Lartic Acid, which will acidify the solution: thus, leading to protein danaturation. Therefore, on heating sour milk. skin formation on milk wil be increased. 3. Explain the mechanism involved in the formation of the fim. The fim. which is also knawn as mik skin. is formed due to fatuorotain interaction. On boiling milk, the water present at the surface will evaporate, thereby leading to exposure of the fats and proteins molecules which bind and thus, form milk fim. B. Curdling of Milk This refers to the precipitation of milk proteins, especially casein. In infants, the enzyme rennin helps to bring about curdling. This makes the milk easier to digest. However, in adults, HCI and pepsin (there is no rennin) are responsible for curding whatever mik adults take in their diet. Mik is converted into curd or yogurt by the process of fermentation. Milk consists of globular proteins called casein. The curd foms because of the chemical reaction between the lactic acid bacteria and casein. During fermentation, the bacteria use enzymes to produce energy (ATP) from lactose. The byproduct of ATP production is lactic acid. Lactic acid acts on globular proteins present in the milk and denatures them. This denaturation destroys the tertiary and quaternary structures of
proteins. The globular proteins are converted into fibrous proteins, thus giving a thick
texture to the mik due to the coagulation of the proteins.
Procedure:
a. Place 1 mL of fresh milk
b. Add 2 drops of rennin solution and 0.26% HCI.
a. Heat the test tube to 40'C in a water bath for 15 minutes.
Solution tested
Result
Test tube with Rennin sol'n + 0.25% HCI
C. Constituents of Milk
C1. Preparation of Casein
a. Dlute 10 ml of canned milk by adding 2 ml of water to a beaker.
b. Add dilute acetic acid drop by drop until a precipitate is formed. Avcid adding
an excess of the acid to avoid the dissolving of the precipitate.
Filter off the precipitate, which is presumably casein. Save the filtrate for the
experiment on coagulable proteins.
c2. Test on Casein/Test for Proteins
a. Dry the precipitate between sheets of filter paper.
b. Place the casein precipitate in a test tube and add 10 drops of Biuret
reagent.
c. Shake well and observe any change in color.
Guide Questions:
1. What is the resulting color obtained from the Biuret test?
The formation of violet coloration confirms the presence of proteins.
2. Does milk contain protein (casein)?
Yes. Cassin is one of two maior proteins found in milk, aoonunting for
pround B0% of protein content.
d. Boil the filtrate from procedure C1. Filter any precipitate that may form upon
boiling. If no precipitate is formed, then no need to filter. Use the filtrate for
the next four tests.
C3. Test for Carbohydrates
a. To 1 mL of the filtrate, add 2 ml of Benedict's solution.
b. Heat the mixture in water,
Guide Questions:
1. What is the resulting color for this test?
Brinkred pracinitate
2. What carbohydrate is present in milk?
Baducina disaccharida - Lactosa
C4. Test for Phosphate
a. To another 1 ml of the fitrate, add 1 ml of ammonium molybdate.
b. Observe the formation of the precipitate.
Guide Questions:
1. What is the color of the precipitate formed?
2. What are the chemical name and the chemical formula for the precipitate
formed?
Ammonium Phosnhomolvhdate - (NHAPO12Mo0
CS. Test for Chlorides
a. To 1 ml of the filtrate, add 5 drops of silver nitrate solution.
Guide Question:
1. Does milk contain chlorides?
CG. Test for Calcium
a. To another 1 ml of the filtrate, add 5 drops of potassium coxalate solution.
Guide Questions:
1. What is the color of the precipitate?
2. What is the chemical name and formula for the precipitate formed?
C7. Test for Sulfates
a. To another 1 ml of the filtrate, add 5 drops of barium chloride solution.
Observation:
Summary of Results (Constituents of Milk)
Results
Formula of the () resullt
Test/Reagents
Color
Biuret test
Benedict's test
Phosphate
Chlorides
Calcium
Transcribed Image Text:proteins. The globular proteins are converted into fibrous proteins, thus giving a thick texture to the mik due to the coagulation of the proteins. Procedure: a. Place 1 mL of fresh milk b. Add 2 drops of rennin solution and 0.26% HCI. a. Heat the test tube to 40'C in a water bath for 15 minutes. Solution tested Result Test tube with Rennin sol'n + 0.25% HCI C. Constituents of Milk C1. Preparation of Casein a. Dlute 10 ml of canned milk by adding 2 ml of water to a beaker. b. Add dilute acetic acid drop by drop until a precipitate is formed. Avcid adding an excess of the acid to avoid the dissolving of the precipitate. Filter off the precipitate, which is presumably casein. Save the filtrate for the experiment on coagulable proteins. c2. Test on Casein/Test for Proteins a. Dry the precipitate between sheets of filter paper. b. Place the casein precipitate in a test tube and add 10 drops of Biuret reagent. c. Shake well and observe any change in color. Guide Questions: 1. What is the resulting color obtained from the Biuret test? The formation of violet coloration confirms the presence of proteins. 2. Does milk contain protein (casein)? Yes. Cassin is one of two maior proteins found in milk, aoonunting for pround B0% of protein content. d. Boil the filtrate from procedure C1. Filter any precipitate that may form upon boiling. If no precipitate is formed, then no need to filter. Use the filtrate for the next four tests. C3. Test for Carbohydrates a. To 1 mL of the filtrate, add 2 ml of Benedict's solution. b. Heat the mixture in water, Guide Questions: 1. What is the resulting color for this test? Brinkred pracinitate 2. What carbohydrate is present in milk? Baducina disaccharida - Lactosa C4. Test for Phosphate a. To another 1 ml of the fitrate, add 1 ml of ammonium molybdate. b. Observe the formation of the precipitate. Guide Questions: 1. What is the color of the precipitate formed? 2. What are the chemical name and the chemical formula for the precipitate formed? Ammonium Phosnhomolvhdate - (NHAPO12Mo0 CS. Test for Chlorides a. To 1 ml of the filtrate, add 5 drops of silver nitrate solution. Guide Question: 1. Does milk contain chlorides? CG. Test for Calcium a. To another 1 ml of the filtrate, add 5 drops of potassium coxalate solution. Guide Questions: 1. What is the color of the precipitate? 2. What is the chemical name and formula for the precipitate formed? C7. Test for Sulfates a. To another 1 ml of the filtrate, add 5 drops of barium chloride solution. Observation: Summary of Results (Constituents of Milk) Results Formula of the () resullt Test/Reagents Color Biuret test Benedict's test Phosphate Chlorides Calcium
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