Test for glucose (a reducing sugar)
1. Add Benedict's solution into sample solution in a test tube
2. Heat at 60 - 70 °c in water bath for 5 minutes
3. Take a test tube out of a water bath and observe the color
A positive test will show a color change from blue to orange or brick red
Test for starch using iodine
1. We can use iodine to test for the presence or absence of starch in a
food sample
2. Add drops of iodine solution to the food sample
A positive test will show a color change from orange-brown to blue-black
Test for protein
1. Add drops of Biuret solution to the food sample
A positive test will show a color change from blue to violet / purple
Test for lipids
1. Food sample is mixed with 2cm3 of ethanol and shaken
2. The ethanol is added to an equal volume of cold water
A positive test will show a cloudy emulsion forming