Active Learn Quick Quiz 1f.pptx
Chemical food tests can be used to identify which food groups are found in certain items. A calorimeter can be used to measure the amount of energy in an item of food.
Benedict's test:
Benedict's solution is used to identify the presence of reducing sugars. The solution is added to the food sample and heated.
Biuret test:
This test is used to identify protein. Potassium hydroxide is mixed with a sample of food. Copper sulfate solution is added and a colour change may be seen.
Ethanol emulsion test:
This test is used to identify fats and oils (lipids) in a food sample. The food is mixed with ethanol and shaken. Some of this is then added to water and shaken again. If a cloudy emulsion is formed then fats/oils are present.
Iodine test:
This is used to test for the presence of starch in a food sample. Iodine is added to a sample and a colour change from orange to blue-black is a positive result.
Calorimetry:
We can measure the amount of energy in food by burning it in a calorimeter:
Worksheets: