Food Tests

• What is the purpose of food tests?

  To identify the type of food molecule a sample contains
• What are the steps to prepare a food sample for testing?

  1. Break up the food using a pestle and mortar
  2. Transfer to a beaker and add distilled water
  3. Stir the mixture to dissolve some food
  4. Filter the solution to remove solid bits
• What is the first step in the Benedict's test for sugars?


  Prepare a food sample and transfer 5cm³ to a test tube
• At what temperature should the water bath be set for the Benedict's test?


  75°C
• What color change indicates the presence of reducing sugars in the Benedict's test?


  The solution changes from blue to green, yellow, or brick-red
• What is the purpose of the iodine solution in food testing?


  To test for the presence of starch
• What color change indicates the presence of starch when using iodine solution?


  The solution changes from browny-orange to black or blue-black
• What is the Biuret test used for?


  To test for the presence of proteins
• What color change indicates the presence of protein in the Biuret test?


  The solution changes from blue to purple
• What is the Sudan III test used for?


  To test for the presence of lipids
• What happens to the mixture in the Sudan III test if lipids are present?


  The mixture separates into two layers, with the top layer being bright red
• What safety precautions should be taken during food tests?

  Wear safety goggles and wash off any spills on skin immediately
• Why is it important to be cautious around the water bath during the Benedict's test?


  Because it can cause burns if not handled carefully
• What is a hazard associated with Sudan III stain solution?


  It is flammable
• What are some common foods that contain starch?

  • Pasta
  • Rice
  • Potatoes
• What are some common foods that contain protein?


  • Meat
  • Cheese
• What are some common foods that contain lipids?


  • Olive oil
  • Margarine
  • Milk
• What are enzymes?


  Biological catalysts that speed up chemical reactions
• What do enzymes do?


  They catalyze biochemical reactions in the body
• Which food contains starch?

  Pasta
• Which enzyme breaks down starch?

  Amylase
• Name a food that contains protein.


  Meat
• Which enzyme breaks down protein?


  Protease
• Name a food that contains lipids.


  Olive oil
• Which enzyme breaks down lipids?

  Lipase
• What are the products of digestion?


  Nutrients such as amino acids, fatty acids, and glucose
• Where does digestion take place?

  In the digestive system
• What is the function of the oesophagus?


  To transport food from the mouth to the stomach
• What is the function of the stomach?


  To digest food using acids and enzymes
• What is the function of the small intestine?


  To absorb nutrients from digested food
• What is the function of the large intestine?


  To absorb water and form waste
• What is the function of the rectum?


  To store waste before it is expelled