Food tests + Calorimeters

• What is the substrate of amylase?

  Starch ( Carbohydrates )
• What is the substrate of lipase?

  Lipids
• What are proteins broken down into?

  Protease
• What are lipids broken down into?

  fatty acids + glycerol
• What are proteins broken down into?

  Amino acids
• What are the 4 types of chemicals used to test for the presence of different biological molecules?

  Benedict's Solution

  Iodine

  Ethanol

  Potassium hydroxide + Copper Sulphate
• What is used to test for reducing sugars?

  Benedict's Solution
• How do you test for reducing sugars?

  • Blue when first added to sample
  • Heated in water bath 75 degrees
  • Forms coloured precipitate
• What is the colour order from small to lots of sugar for Benedict's solution?

  Blue, Green, Yellow, Orange, Brick red
• What colour does iodine change to when starch is present?

  Blue-Black
• How do you test for starch?

  1-1 drop of starch in each spotting tile

  2-Add a drop of iodine

  3-UNTIL substance stops turning black
• How do you test for lipids?

  1-Ethanol mixed + shaken around for 1 min

  2-Milky emulsion = lipids present
• What else can you cal the KOH + CUSO4 test called?

  Biuret test
• How can protein be tested?

  1-Add few drops of KOH (colourless)

  2-To solution -> so it becomes alkaline

  3-Add CuSO4

  4-Bright blue -> purple if present
• What is calorimetry?

  Method of burning food to see amount of energy within
• Describe the method of calorimetry

  1-Measure mass of food sample

  2-Secure on mounted needle

  3-Add water to boiling tube + secure using clamp + stand

  4-Set fire + hold burning food under tube

  5-When finished burning , measure temp of water again
• What is the formula to calculate calorimetry?

  Energy in food = Mass of H2O x Temp change of H2O x 4.2
• How do you calculate energy per gram of food?

  Energy in food / mass of food