rp 4: food tests

• 1. take food sample & grind with distilled water using a mortar & pestle
  2. transfer paste to a beaker & add more distilled water
  3. stir - chemicals in food dissolve in water
  4. filter solution
• test for starch

  iodine - orange turns blue-black if starch is present
• test for protein

  biuret solution - blue, if protein is present turns lilac
• test for lipids

  • do not filter solution
  • distilled water & ethanol
  • shake solution
  • if lipids are present, a white cloudy emulsion forms
• test for glucose

  • benedicts solution
  • heat
  • if glucose is present colour will turn green/orange/red