BIO - food tests

• the Benedict's test is used to test for sugars
• when testing for sugars you must place the test tube into a water bath
• if the food sample contains sugar the solution in the test tube will change from blue to green, yellow or red - it depends on how high the sugar concentration is
• iodine solution is used to test for starch
• if the food sample contains starch the colour of the solution will change from browny-orange to blue or black
• the biuret test is used to test for proteins
• if the food contains protein, the solution will change from blue to purple
• the sudan III test is a test for lipids (ethanol solution)
• the sudan III solution stains lipids
• if the sample contains lipids, the mixture will separate into two layers - the top layer will be bright red