food tests

• benedict's test tests for sugars
• if the benedict's solution changes colour, then sugar is present in the food
• iodine solution is used to test for starch
• when starch is present, iodine solution will turn blue-black
• to test for proteins, use the biuret test
• when proteins are present, the biuret test will go from blue to purple
• you can test for lipids using sudan III solution
• when lipids are present, the sudan III will separate the mixture, the top layer turning bright red