Lesson 1.5: Investigation: Testing for Nutrients

Fats are an important nutrient in your diet.  Another name for fats is lipids.  What are the tests for fats or lipids? 

Watch the following video clip to see what the tests are and how they are done.

Now, answer the following questions about the test for fat.

 

Question 1. What chemical is used to test for fat in a food?

Question 2. Explain how the test is performed.

Question 3. What happens in the test if fat is in a food?

Question 4. What happens if no fat is in the tested food?

Question 5. What other test can be used to test for fats?

Question 6. Explain how this test is performed.

Question 7. What happens in the test if fat is in a food?

Question 8. What happens if no fat is in the tested food?

 

Check your answers with those that follow.

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 1. What chemical is used to test for fat in a food?

Sudan IV is used to test for fat (lipids). 

Question 2. Explain how the test is performed.

Add a small amount of Sudan IV solution to the food (the food should be in solution if it is not a liquid) and shake for two minutes.

Question 3. What happens in the test if there is fat in a food?

If fat is in the food, Sudan IV will dissolve, and the fats will turn pink or red. 

Question 4. What happens if there is no fat in the tested food?

If no fat is in the tested food, the Sudan IV will not dissolve, and the solution will not take on the pink colour.

Question 5. What other test can be used to test for fats?

The translucence test is the other test used for fats. 

Question 6. Explain how the test is performed.

Rub a small amount of the food onto a piece of unglazed brown paper.

Question 7. What happens in the test if there is fat in a food?

If fat is in the food, the paper will be translucent where the fat was absorbed by the paper. 

Question 8. What happens if no fat is in the tested food?

If no fat is in the tested food, the brown paper remains opaque (you cannot see through it).

 


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