1.13 Core practical: Investigating macronutrients

Question 1

What chemical is used to test for starch?

Answer 1

Iodine solution

Question 2

What is the method to test for starch?

Answer 2

1- Add the iodine solution directly to the substance to be tested and look for a colour change.

Question 3

What is the result if starch is present?

Answer 3

orange —-> blue/ black

Question 4

What chemical is used to test for reducing sugars?

Answer 4

Benedict’s solution

Question 5

What is the method to test for reducing sugars?

Answer 5

1- Add Benedict’s to the solution to be tested.

2- Heat for 2 minutes in a water bath at boiling point and look for a colour change

Question 6

What is the result is reducing sugars are present?

Answer 6

blue —-> brick red

Question 7

What chemical is used when testing for protein?

Answer 7

Biuret’s solution

Question 8

What is the method for testing for protein?

Answer 8

1- Add a few drops of potassium hydroxide and stir.

2- Add a few drops of copper sulfate solution and stir.

Question 9

What is the result if protein is present?

Answer 9

blue —-> purple

Question 10

What chemical is used when testing for lipids (emulsion test)?

Answer 10

Ethanol

Question 11

What is the method for testing for lipids (fats)?

Answer 11

1- Add ethanol solution to be tested and shake thoroughly

2- Add water and look for colour change

Question 12

What is the result if lipids (fats) are present?

Answer 12

clear —-> cloudy

Question 13

What is a qualitative food test?

Answer 13

Show only whether the substance is present or not (e.g. iodine test)

Question 14

What is a quantitative food test?

Answer 14

Shows a definite measurement of how much of the substance is
there

Question 15

What is a semi quantitative food test?

Answer 15

Give some information of how much of a substance is there but there is no measurement (e.g. benedicts and biuret test)