food tests

• What should food be prepared as before testing?

  Ground into small pieces
• What reagent is used to test for glucose?


  Benedict’s Reagent
• What temperature should the Benedict’s reagent be heated to for testing glucose?


  Above 65 degrees Celsius
• What color change indicates the presence of glucose when using Benedict’s reagent?


  Blue to brick red, orange, green, or yellow
• Which reagent is used to test for protein?


  Biuret reagent
• What color change indicates the presence of protein when using Biuret reagent?


  Blue to lilac
• What reagent is used to test for starch?


  Iodine
• What color change indicates the presence of starch when using iodine?


  Orange/brown to blue/black
• Which reagent is used to test for lipids?


  Ethanol
• What indicates the presence of lipids when using ethanol and water?


  Clear to cloudy
• What is a method to test for fats using filter paper?


  Rubbing food onto filter paper
• What color change indicates fat presence on filter paper?


  Translucent
• What is the positive result for protein using Biuret reagent?

  Turns blue to purple/lilac
• What is the positive result for starch using iodine?

  Turns from orange/brown to blue/black
• What is the positive result for simple sugars using Benedict’s solution?

  Turns from blue to red, orange, yellow, or green
• What is the positive result for fats using ethanol and water?

  Turns from clear to cloudy
• What are the steps to test for starch using iodine?

  1. Put food in a spotting tile
  2. Add a few drops of iodine solution
  3. Observe color change: orange to blue-black
• What are the steps to test for glucose using Benedict’s solution?

  1. Place food in a test tube
  2. Cover with Benedict’s solution
  3. Heat gently in a water bath to 80°C for 5 minutes
  4. Observe color change: blue to orange-red
• What are the steps to test for protein using Biuret solution?

  1. Add food to a test tube
  2. Add 1cm³ of Biuret solution
  3. Observe color change: blue to purple
• What are the steps to test for fats using ethanol?

  1. Add food to a test tube
  2. Cover with ethanol
  3. Add water
  4. Observe: cloudy white indicates fat
• What are the main nutrients and their functions in the body?

  • Carbohydrates: Energy and insulation
  • Protein: Health (teeth and bones)
  • Fats: Digestive health
  • Water: Major component of bodily fluids
  • Vitamins: Growth and repair
  • Minerals: Prevent deficiency diseases
  • Fibre: Energy
• What is the importance of food in our diet?

  • Source of energy
  • Building blocks for new growth
  • Contains a mixture of nutrients
• What safety precautions are needed when conducting food tests?

  • Use gloves and goggles
  • Handle reagents carefully
  • Follow proper disposal methods
• What is the significance of describing the tests in an exam?

  • Name chemicals used
  • Describe usage and color changes
  • Explain negative results and safety precautions
• What is the required practical for food tests?

  Testing 3-4 foods for starch, sugar, fat, and protein
• What should be completed in the results table during food tests?

  Observations for starch, sugar, protein, and fat
• What is the importance of reproducibility in results?

  Ensures reliability of the test outcomes
• What is the role of carbohydrates in the body?

  Provide energy and insulation
• What is the role of proteins in the body?

  For health, e.g., teeth and bones
• What is the role of fats in the body?

  Support digestive health
• What is the role of water in the body?

  Major component of bodily fluids
• What is the role of vitamins in the body?

  Growth and repair
• What is the role of minerals in the body?

  Prevent deficiency diseases
• What is the role of fibre in the body?

  Energy