Centre Of Foundation Studies, UiTM
Foundation Biology I / BIO091
EXPERIMENT 1: IDENTIFICATION OF BIOLOGICAL MOLECULES IN FOOD
Objectives
1. To carry out tests for reducing sugar, starch, proteins, and lipids.
2. To determine the biological molecules in certain food samples.
Materials : Distilled water, glucose, albumin, starch, vegetable oil, Benedict’s solution, Biuret
reagent, Lugol’s solution, Sudan IV solution and peanuts.
Apparatus : Test tubes, test tube rack, beakers, disposable dropper, spatula, vortex mixer, water
bath or hot plate.
Procedure
1. Set water bath to 95°C or fill half of a 250 ml beaker with water and bring water to boil using a hot
plate.
2. Place eight (8) test tubes in a test tube rack. Each test requires two (2) test tubes.
3. An unknown sample solution is provided and labelled as sample A.
Test for Reducing Sugars
4. Samples: (i) glucose and (ii) sample A.
i) Label 2 test tubes as glucose and sample A.
ii) Pipette 2.0 ml of each solution into each test tube.
iii) Add 2.0 ml of Benedicts solution to each test tube.
iv) Gently shake the test tubes to mix the solutions. Record the initial color of solutions.
v) Place both the test tubes in water bath for 5 minutes.
vi) Remove the test tubes from water bath.
vii) Observe and record the final color of solutions.
Test for Proteins
5. Samples: (i) albumin and (ii) sample A.
i) Label 2 test tubes as albumin and sample A.
ii) Pipette 2.0 ml of each solution into each test tube.
iii) Observe the initial color of Biuret’s reagent.
iv) Add 2.0 ml of Biuret’s reagent to each test tube.
v) Gently shake the test tubes to mix the solutions. Record the initial color of solutions.
vi) After 2 minutes, observe and record the final color of solutions.
Test for Starch
6. Samples: (i) starch and (ii) sample A.
i) Label 2 test tubes as starch and sample A.
ii) Pipette 2.0 ml of each solution into each test tube.
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, Centre Of Foundation Studies, UiTM
Foundation Biology I / BIO091
iii) Observe the initial color of Lugol’s solutions.
iv) Add 2.0 ml of Lugol’s solution to each test tube.
v) Gently shake the test tubes to mix the solutions.
vi) Observe and record the final color of solutions.
Test for Lipids
7. Samples: (i) vegetable oil and (ii) sample A.
i) Label 2 test tubes as vegetable oil and sample A.
ii) Pipette 2.0 ml of each solution into each test tube.
iii) Observe the initial color of Sudan IV solution.
iv) Add 10 drop of Sudan IV solution to each test tube.
v) Homogenize solutions in the test tubes using a vortex mixer.
vi) Add 2.0 ml of distilled water to each test tube.
vii) Observe and record the changes in the solutions.
2
Foundation Biology I / BIO091
EXPERIMENT 1: IDENTIFICATION OF BIOLOGICAL MOLECULES IN FOOD
Objectives
1. To carry out tests for reducing sugar, starch, proteins, and lipids.
2. To determine the biological molecules in certain food samples.
Materials : Distilled water, glucose, albumin, starch, vegetable oil, Benedict’s solution, Biuret
reagent, Lugol’s solution, Sudan IV solution and peanuts.
Apparatus : Test tubes, test tube rack, beakers, disposable dropper, spatula, vortex mixer, water
bath or hot plate.
Procedure
1. Set water bath to 95°C or fill half of a 250 ml beaker with water and bring water to boil using a hot
plate.
2. Place eight (8) test tubes in a test tube rack. Each test requires two (2) test tubes.
3. An unknown sample solution is provided and labelled as sample A.
Test for Reducing Sugars
4. Samples: (i) glucose and (ii) sample A.
i) Label 2 test tubes as glucose and sample A.
ii) Pipette 2.0 ml of each solution into each test tube.
iii) Add 2.0 ml of Benedicts solution to each test tube.
iv) Gently shake the test tubes to mix the solutions. Record the initial color of solutions.
v) Place both the test tubes in water bath for 5 minutes.
vi) Remove the test tubes from water bath.
vii) Observe and record the final color of solutions.
Test for Proteins
5. Samples: (i) albumin and (ii) sample A.
i) Label 2 test tubes as albumin and sample A.
ii) Pipette 2.0 ml of each solution into each test tube.
iii) Observe the initial color of Biuret’s reagent.
iv) Add 2.0 ml of Biuret’s reagent to each test tube.
v) Gently shake the test tubes to mix the solutions. Record the initial color of solutions.
vi) After 2 minutes, observe and record the final color of solutions.
Test for Starch
6. Samples: (i) starch and (ii) sample A.
i) Label 2 test tubes as starch and sample A.
ii) Pipette 2.0 ml of each solution into each test tube.
1
, Centre Of Foundation Studies, UiTM
Foundation Biology I / BIO091
iii) Observe the initial color of Lugol’s solutions.
iv) Add 2.0 ml of Lugol’s solution to each test tube.
v) Gently shake the test tubes to mix the solutions.
vi) Observe and record the final color of solutions.
Test for Lipids
7. Samples: (i) vegetable oil and (ii) sample A.
i) Label 2 test tubes as vegetable oil and sample A.
ii) Pipette 2.0 ml of each solution into each test tube.
iii) Observe the initial color of Sudan IV solution.
iv) Add 10 drop of Sudan IV solution to each test tube.
v) Homogenize solutions in the test tubes using a vortex mixer.
vi) Add 2.0 ml of distilled water to each test tube.
vii) Observe and record the changes in the solutions.
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