Food tests

• What is the purpose of the Benedict's test?

  To test for reducing sugars
• What does the iodine test detect?

  Presence of starch in food
• What does the buret test identify?

  Presence of proteins in food
• What is the Sudan 3 test used for?

  To test for lipids in food
• What is the emulsion test for lipids?

  A test for lipids using ethanol and water
• What is the first step in preparing a food sample for testing?

  Break it up using a mortar and pestle
• How do you filter the food sample solution?

  Using a funnel lined with filter paper
• What happens to the Benedict's solution if reducing sugars are present?

  It changes color from blue to green, yellow, or brick red
• What color does the iodine solution turn if starch is present?

  Blue-black color
• What color change indicates the presence of proteins in the buret test?

  From blue to pink or purple
• What is the specific procedure for the buret test in the Edexcel course?

  Add potassium hydroxide followed by copper sulfate
• What indicates the presence of lipids in the Sudan 3 test?

  A bright red layer at the top
• What is the result of the emulsion test if lipids are present?

  A cloudy white color appears
• How much food sample is needed for the Sudan 3 test?

  5 centimeters cubed
• How many drops of Benedict's solution are added in the test?

  About 10 drops
• What temperature should the water bath be set to for the Benedict's test?

  75 degrees Celsius
• What should you do for safety when using the water bath?

  Use a test tube holder and point away
• What is the initial color of the iodine solution before testing?

  Browny orange color
• What is the purpose of shaking the test tube gently after adding reagents?

  To mix the solution thoroughly
• How do the tests for sugars, starch, proteins, and lipids differ in their procedures?

  Each test uses different reagents and methods
• What common step is involved in preparing food samples for all tests?

  Crushing and dissolving the food in water
• What is the significance of the color changes in these tests?

  They indicate the presence of specific nutrients
• What is the final step in the preparation of the food sample?

  Filter out solid bits using a funnel