Food tests

• Before carrying out a test, you need to prepare your food sample:

  • Get a piece of food and break it up in a pestle and mortar
  • Add distilled water and stir to dissolve the food
  • Filter the solution using a funnel lined with filter paper to get rid of the solid bits.
• Benedict's test for glucose:

  • Add Benedict's solution to sample
  • Heat the solution in a water bath
  • If there is glucose present - solution will go from blue to green/yellow in LOW concentration. Orange/brick-red in HIGH concentration.
• Starch test with iodine

  • If the sample contains starch, it will turn from yellow/brown to black
• Biuret test for proteins:

  • If the sample contains proteins, it will go from blue to purple
• Ethanol test for lipids:

  • Add ethanol and gently shake the tube
  • If the sample contains lipids, a white-cloudy emulsion forms at the top.