1. Starter Look at food labels Why is it useful to put the ingredients and nutritional value of food on labels? What is a food scientist? What is the Foods Standards Agency?

2. Food Tests Learning objectives: All students must: Carry out food tests for starch, sugars, protein and fat. Most students should: Describe why food labels are important. Some students could: Describe the food tests

3. Video How do scientists come up with food labels? Watch the video and think about: – What amounts of energy and nutrients should we be eating? – Why is it important to test foods and create food labels?

4. Testing for Starch Add a few drops of orange iodine solution to your food sample. If starch is present the sample will turn blue black. Testing for Glucose Add some water to your food in a test tube to make a solution. Add an equal volume of blue Benedict’s solution and heat in a water bath. If glucose is present the solution will turn green,orange or brick red depending on how much glucose is present. Testing for Protein Add some water to your food sample in a test tube and shake it. Then add a few drops of blue biuret solution. If protein is present the solution will turn lilac or blue depending on how much protein is present. Testing for Fats Mix the food sample with a third of a tube of ethanol and shake well. Filter the mixture to remove any solids. Add some clean water to the filtrate. If fat is present a white emulsion will form and float.

5. Complete Table FOOD STARCH TEST GLUCOSE TEST PROTEIN TEST FAT TEST observationconclusionobservationconclusionObservationconclusionobservationconclusion A B C D Testing foods for nutrients.

6. Plenary Identify any risks associated with the practical methods for testing foods in the lab. Explain how risks can be minimised. Imagine students do not have a water bath and are considering heating ethanol solution using a bunsen burner. Evaluate the risk associated with this method. Should this risk be taken.

7. TASK: Food Test Summary Divide a piece of paper into quarters. Describe the method for each nutrient in a different quarter of your paper. Include drawings to help you remember! – Test For Starch – Test For Glucose – Test For Protein – Test For Fats