Food tests

Question 1

Test for starch and starting colour and positive test

Answer 1

Iodine
Starting colour - Orange-brown
Positive result - Blue black

Question 2

Test for sugars and starting colour and positive test

Answer 2

Benedict’s
Starting colour - Light blue
Positive result - Green to brick-red

Question 3

Test for lipids and starting colour and positive test

Answer 3

Ethanol
Starting colour - Colourless
Positive result - Cloudy emulsion

Question 4

Test for protein and starting colour and positive test

Answer 4

Biuret
Starting colour - Blue
Positive result - Lilac-purple

Question 5

How to carry out test for starch?

Answer 5

1- Add food sample to test tube
2- Add a few drops of iodine
3- Swirl and note down any colour changes

Question 5

How to carry out test for sugars?

Answer 5

1- Set up traditional water bath with blue bunsen flame
2- Add food sample to a test tube with a few drops of benedict’s solution
3- Put test tube in water bath for 5 minutes ad note colour change

Question 5

How to carry out test for Lipids?

Answer 5

1- Add food sample to a test tube
2- Add a few drops of distilled water and a few drops of ethanol
3- Swirl solution and note down observations

Question 6

How to carry out test for proteins?

Answer 6

1- Add food sample test tube
2- Add a few drops of biuret A and biruet B
3- Swirl solution and note down colour changes