Food Testing

We can see what’s in food by running different chemical tests.

We can test for starch by dropping iodine solution on to the food solution. If it changes the solution dark blue - black colour, the food contains starch.

To test for lipids you rub some of the food onto a piece of filter paper. Hold the paper up to the light and if the paper is translucent the food contains lipids.

You could also add a few drops of ethanol into a food solution, shake the test tube and leave it for 1 minute.

Poor the ethanol into a test tube of water. If the solution is cloudy the food contained lipids.

Simple sugars, like glucose, can be detected by benedict’s solution.

Originally benedict solution is blue, when added with sugar and heated it becomes orange-red.

To detect proteins you need copper sulphate solution and sodium hydroxide solution.

Copper sulphate solution is pale-blue liquid and Sodium hydroxide solution is colourless liquid.

Add a few drops of copper sulphate and a few drops of sodium hydroxide to the food solution. If the solution turns purple you have protein.