Food Tests

Question 1

What is the test for sugar

Answer 1

Prepare a food sample and transfer 5cm3 to a test tube.
Prepare a water bath so that it’s set to 75°C
Add some Benedicts solution to the test tube using a pipette
Place the test tube in the water bath and leave it for 5mins (make sure it is pointing away from you)
If there is little sugar it will turn green and loads of sugar it will turn yellow/brick-red

Question 2

What is the test for starch

Answer 2

Make a food sample and transfer 5cm3 of your sample to a test tube
Add a few drops of iodine solution and gently shake the tube to mix the contents. If it contains starch the solution will go from orange to blue-black.

Question 3

What is the test for proteins

Answer 3

Prepare a sample of your food and transfer 2cm3 to a test tube.
Add 2cm3 of Biuret solution to the sample and mix by gently shaking.
If it contains protein the solution will go from blue to purple

Question 4

What is the test for lipids

Answer 4

Prepare a sample of the food your testing, transfer 5cm3 to a test tube.
Use a pipette to add 3 drops of Sudan III stain solution to the test tube and gently shake it.
If the sample contains lipids, this mixture will seperate into two layers, the top layer will be bright red