Food provides us with the energy to grow and move and helps keep all the parts of our body working properly.
Marathon runners often have a meal high in carbohydrates the night before a race to provide them with the slow releasing energy they need to run.
It is important for us to know then exactly what is in our foods so we can ensure we are getting the balanced diet that our bodies need. Below are a few tests that can be used to show if fats, proteins, starch or sugars are present in the foods we eat.
The Chemical Tests for Carbohydrates
There are two types of carbohydrate. One is starch and the other is sugars.
The test for starch is using a chemical called iodine. When added to something containing starch, iodine will turn from a red/brown colour to a blue/black colour.
The test for sugars is using a chemical called benedict’s solution. When added to something containing sugars, benedict’s solution will turn from blue to orange.
The Chemical Test for Proteins
The test for protein is using a chemical called Biuret solution. When added to something containing protein, Biuret solution will turn from a blue colour to a pink/purple colour.
The Chemical Test for Fats
The test for fats is not quite as simple as the tests for carbohydrates and protein. It requires 2 steps:
Firstly, add the food to be tested to a small amount of ethanol and let it dissolve (the solution may need to be heated in order for it to dissolve fully. DO NOT USE A BUNSEN BURNER OR A NAKED FLAME, ethanol is highly flammable therefore a water bath should be used.)
If the solution remains colourless, there are no fats present. If a layer of cloudy white emulsion forms at the top, then there is fat in this type of food.