Food Test Experiments

Question 1

Starch

Answer 1

Add a few drops of iodine solution

If the starch goes blue/black it is a positive result

If it stays an orange colour it is a negative result

Question 2

Reducing sugars (e.g. Sugars)

Answer 2

1) Add a few drops of Benedict’s solution
2) Then heat gently for approximately 10 minutes

If it turns to a brick red colour it is a positive result

If it stays a blue colour it is a negative result

Question 3

Proteins

Answer 3

1) Add a few drops of Biuret 1 and Biuret 2
2) Then shake the test tube gently

If it turns into a violet colour it is a positive result

If it stays a blue colour it is a negative result

Question 4

Fats/Lipids

Answer 4

Add a few drops of water and a few drops of ethanol

Then if a white precipitate layer forms it is a positive result