Food tests - Organisation P1

Question 1

What does iodine test for?

Answer 1

Starch

Question 2

What does Benedict’s solution test for?

Answer 2

Reducing Sugars

Question 3

What does biuret test for?

Answer 3

Proteins

Question 4

What does emulsion test for?

Answer 4

Lipids

Question 5

What colour does iodine change from and to when starch is present?

Answer 5

Orange-brown to Blue-black

Question 6

What colour does biuret change from and to when protein is present?

Answer 6

Blue to purple

Question 7

What colour does emulsion change from and to when lipid is present?

Answer 7

No emulsion to white emulsion (milky white)

Question 8

What colour does Benedict’s solution change from and to when reducing sugars are present?

Answer 8

Blue to green to yellow/orange to red

Blue means no reducing sugars. It ascends from green to red.

Question 9

Explain the method for biuret.

Answer 9

1. Add a few drops of food solution into the test tube
2. Add a similar amount of biruet to the test tube
3. Results will be shown - Blue to purple

Question 10

Explain the method for iodine.

Answer 10

1. Make sure that the food solution is not solid but a bit liquid, grind it with a pestle and mortar
2. Add a few drops of iodine onto the spotting tile
3. Results will be shown - orange/brown to blue/black

Question 11

Explain the method for Benedicts.

Answer 11

1. Add food solution to test tube
2. Add few drops of Benedicts solution
3. Boil some water
4. Pour the boiling water into a water bath.
5. Place test tubes in water bath
6. Results will be shown

Question 12

Explain the method for emulsion.

Answer 12

1. Add food solution into test tube
2. Add few drops of distilled water
3. Add a few drops of ethanol
4. Shake the test tube gently
5. Results would be shown.