Podcast
Questions and Answers
Which of the following is NOT a component of proteins?
Which of the following is NOT a component of proteins?
What is the purpose of the Benedict's test?
What is the purpose of the Benedict's test?
In the Biuret's test for proteins, a positive result is indicated by what color change?
In the Biuret's test for proteins, a positive result is indicated by what color change?
A solution turns cloudy white after performing an emulsion test. What can you conclude?
A solution turns cloudy white after performing an emulsion test. What can you conclude?
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What is the purpose of shaking the ethanol and food sample mixture in the emulsion test?
What is the purpose of shaking the ethanol and food sample mixture in the emulsion test?
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Which of the following is NOT a function of proteins in the body?
Which of the following is NOT a function of proteins in the body?
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What is the main difference between the iodine test for starch and the Benedict's test for glucose?
What is the main difference between the iodine test for starch and the Benedict's test for glucose?
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What is the function of lipids in the body?
What is the function of lipids in the body?
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Flashcards
Starch test
Starch test
Test for starch using iodine solution.
Benedict’s test
Benedict’s test
Test for glucose using Benedict's solution.
Positive glucose test
Positive glucose test
Color changes to green, orange, or brick red.
Biuret's test
Biuret's test
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Lipid test
Lipid test
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Protein structure
Protein structure
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Structure of lipids
Structure of lipids
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Elements in proteins
Elements in proteins
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Study Notes
Starch Test
- Iodine solution is used to test for starch.
- Place a small sample of the food on a spotting tile.
- Add 2-3 drops of iodine solution to the food sample.
- Observe the colour change.
- Negative result (no starch): orange/brown
- Positive result (starch present): blue/black
Glucose Test
- Benedict's solution is used to test for glucose (simple sugars).
- Prepare a sample of food.
- Put 5 ml of food sample into a test tube.
- Add 5 ml of Benedict's solution, mix thoroughly.
- Place the test tube in a water bath at 80°C for 10 minutes.
- Record the colour change after 10 minutes.
- Negative result (no glucose): blue
- Positive results:
- Low glucose concentration: green/yellow
- Medium glucose concentration: orange
- High glucose concentration: brick red
Protein Test
- Biuret's test is used.
- Prepare a 5 ml sample of the food.
- Add 5 ml of Biuret's solution.
- Mix the solutions thoroughly.
- Observe the colour change.
- Negative result (no protein): solution remains blue.
- Positive result (protein present): solution turns purple.
Lipid Test
- Emulsion test is used to detect lipids.
- Place a small spatula of the food sample in a test tube.
- Add 5 ml of ethanol and shake until the food dissolves (to make it soluble).
- Add 5 ml of water and mix.
- Observe the result.
- Positive result (lipids present): solution turns cloudy white.
- Negative result (no lipids): solution remains clear.
Food Preparation for Testing
- Prepare the food sample (example: bread).
- Place the food sample into a mortar and add a small amount of water.
- Grind the food using a pestle.
- Add 5 ml of water and mix thoroughly.
- Fold filter paper and place it into a funnel.
- Filter the food sample into a small beaker.
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Description
This quiz covers essential biological tests used to identify the presence of starch, glucose, and proteins in food samples. You will learn about the procedures, color changes observed, and the importance of these tests in food analysis. Test your knowledge and understanding of these vital biochemical tests.
