B2.1.2 - Food Tests

Question 1

Which solution do we use to test for sugars?

Answer 1

Benedict’s solution

Question 2

Which solution do we use to test for starch?

Answer 2

Iodine solution

Question 3

What colour is Benedict’s solution when it contains no simple sugars?

Answer 3

Blue

Question 4

What colour is iodine solution when there is no starch present?

Answer 4

Orange

Question 5

What colour is iodine solution in the presence of starch?

Answer 5

Blue/Black

Question 6

How do we prepare a food sample?

Answer 6

1. Crush the food with a pestle and mortar.
2. Add a few drops of distilled water and mix well.

Question 7

What is distilled water?

Answer 7

Pure water (it contains no other chemicals)

Question 8

How do you test for starch?

Answer 8

1. Add a few drops of iodine solution to a food sample.
2. If solution turns blue/black starch is present.

Question 9

How can you test for SOLID lipids?

Answer 9

1. Rube the piece of food on filter paper.
2. Hold paper to light source.
3. If paper turns translucent - lipids are present.

Question 10

What does translucent mean?

Answer 10

Slightly see-through

Question 11

How can you test for lipid in a food solution (LIQUID)

Answer 11

1. Add a few drops of ethanol to the food solution.
2. Shake tube and leave for 1 minute.
3. Pour ethanol into a tube of water.
4. If solution turns cloudy - lipids are present.

Question 12

How do you test for simple sugars?

Answer 12

1. Add a few drops of Benedict’s solution to the food sample.
2. Heat the test tube in a water bath.
3. If the solution turns orange/red the food contains simple sugars.

Question 13

How do you test for protein?

Answer 13

1. Add a few drops of copper sulfate to food solution.
2. Add a few drops of sodium hydroxide.
3. If solution turns purple - proteins are present.

Question 14

What colour is copper sulfate solution?

Answer 14

Blue