1. Chemical Tests for Glucose, Starch, Proteins and Fats.
Food Tests
Chemical Tests for Glucose, Starch, Proteins and Fats.

2. Test for Glucose
Add 2 mL of blue Benedict’s solution to the solution being tested.
Heat gently in a waterbath.
Positive Test – solution turns green, orange or red colour.

3. Test for Glucose
No Glucose
Positive Test for Glucose

4. Test for Starch
Add a few drops of iodine solution to the solution being tested.
Positive Test – solution turns blue / black colour.

5. Test for Starch

6. Test for Protein Add about 1 mL of blue copper sulfate solution and
Add about 1 mL of sodium hydroxide solution to the solution being tested. Now shake the mixture.
Positive Test – the solution turns purple if protein is present.

7. Test for Protein

8. Test for Fats
Put a spot of water on to a piece of filter paper. Label water.
Put a spot of fat or oil on to a piece of filter paper. Label fat or oil.
Leave to dry.

9. Test for Fats Positive Test:
The Fat or Oil spot will remain clear (translucent) while the water mark will disappear.
Fat / Oil
Water

10. Test for Fats Positive Test:
The Fat or Oil spot will remain clear (translucent) while the water mark will disappear.
Fat / Oil
Water