Food Tests

• Carbohydrates

  Include starch and sugars such as glucose
• All chemicals used in these tests are potentially hazardous, so safety goggles must be worn
• Testing for Starch: IODINE SOLUTION

  • Place the sample in a test tube and add iodine solution.
  • A color change from BROWN-ORANGE to BLUE-BLACK signifies the presence of starch.
• Testing for Proteins: BIURET TEST

  • Combine the food sample with Biuret solution in a test tube.
  • Gently shake; a change to PURPLE indicates protein. If no protein, the solution remains BLUE.
• Testing for Lipids: SUDAN III TEST:

  • Add the food sample and Sudan III stain solution to a test tube without filtering.
  • Gently shake the tube. Lipid presence will show as a separate BRIGHT RED LAYER
• Testing for Sugars: BENEDICTS REAGENT

  • Add the food sample to a test tube, mix in Benedict's solution.
  • Heat the tube in a WATER BATH at 75°C for 5 minutes.
  • A color change indicates the presence of reducing sugars, with the color varying from BLUE to GREEN to YELLOW or BRICK-REDdepending on sugar concentration.