Food tests

Question 1

Test for glucose

Answer 1

1. Add benedict’s solution into sample solution in test tube
2. Heat at 60-70deg in water bath for 5 minutes
3. Take test tube out of water bath and observe the colour
4. A positive test will show the colour change from blue to orange or brick red

Question 2

Test for starch

Answer 2

1. We can use iodine to test for presence of starch in a food sample
2. Add drops of iodine to food sample
3. A positive test will show a colour change from orange-brown to blue-black

Question 3

Test for protein

Answer 3

1. Add drops of biuret solution to the food sample
2. A positive test sill show a colour change from blue to violet/purple

Question 4

Test for lipids

Answer 4

1. Food sample is mixed with 2cm^3 of ethanol and shaken
2. The ethanol is added to an equal volume of cold water
3. A positive test swill show a cloudy emulsion forming