food tests

• what is the test for sugars?

  Benedict's solution, has to be heated to 75 °c

  it turns blue to green, yellow or brick red
• what is the test for starch?

  Iodine solution

  it turns browny-orange to black or blue-black
• what is the test for proteins?

  Biuret test.

  it turns blue to purple
• what is the test for fats?

  ethanol test

  it turns colourless to white emulsion
• what is the test for lipids?

  Sudan III test.

  will be separated into two layers, top layer will be bright red
• how to take food samples?

  break up piece of food using pestle and mortar

  transfer the ground up food to beaker and add distilled water

  stir with glass rod to dissolve some of the food

  filter the solution using funnel and filter paper to get rid of solid bits of food