Food tests

• To prepare a food sample for a food test you must:

  • Grind up the food using a pestle and mortar
  • add water and stir to dissolve food
  • filter to remove lumps of food
• Benedicts test is for reducing sugars, it is a colour change from blue to brick red.
• Iodine tests for starch and goes orange to blue/black
• Biuret tests for proteins which goes from blue to purple.
• the 2 tests for lipids are:

  • the emulsion test
  • sudan III stain test which leave a red layer separate on top of solution if lipid present.