Food Tests

• What is the first step in the food testing procedure?

  Tare the food sample and grind it in warm distilled water using a mortar and pestle.
• Why do you add distilled water after grinding the food sample?

  To create a paste that can be transferred for further testing.
• What is the purpose of filtering the solution in the food testing procedure?

  To remove solid bits of food.
• What is the test for starch in food samples?

  • Place 2cm³ of food solution into a test tube.
  • Add a few drops of iodine solution.
  • Observe color change: brown-orange to blue-black indicates starch presence.
• What color change indicates the presence of starch when iodine is added?

  The solution changes from brown-orange to blue-black.
• What is the procedure to test for sugars in food samples?

  • Place 2cm³ of food solution into a test tube.
  • Add 10 drops of Benedict's solution.
  • Heat in a warm water bath for 5 minutes.
  • Observe color change: blue to green, yellow, or red indicates sugar presence.
• What does a color change from blue to green, yellow, or red indicate in the sugar test?

  It indicates the presence of sugars, with color intensity showing the amount.
• How long should the test tube be left in the warm water bath during the sugar test?

  5 minutes.
• If a food solution turns blue-black after adding iodine, what does this mean?

  Starch is present in the food sample.
• If a food solution changes from blue to red after the Benedict's test, what can be concluded?

  A high amount of sugars is present in the food sample.