Biochemical food test

• Iodine solution

  Is used to test for starch. Add the iodine solution directly in the substance to be tested and look for a colour change. It should turn black if starch is present
• Biuret’s solution


  Is used to test for protein. Add biuret’s to the suspension to be tested and wait for a colour change. It should turn purple if protein is present.
• Benedict’s solution


  This is used to test for reducing sugars. Add benedict’s solution to the suspension and heat for 2 minutes in a water bath of boiling point. After this look for a colour change - 2cm deep of benedicts.

  jf the sugars are present it will turn brick red
• Emulsion test


  Is used to find lipids. Add ethanol to the solution to be tested and shake thoroughly. Then add water and look for a colour change. It should turn cloudly/milky if lipid is present