LSE 4

• What is the title of LSE 4?

  Benedict’s Test: Which food samples contain reducing sugars?
• Benedict’s test detects the presence of _.

  reducing sugar
• What metal based reagent is used in Benedict's test?

  copper
• Reducing sugar in solution contain an _ group

  aldehyde
• If reducing sugars are present in the sample, they reduce the _ in benedict’s reagent.

  copper
• The positive result is a red precipitate of

  cuprous oxide
• List the 6 food samples in the experiment.

  Milk

  Groundnut oil

  Wheat flour

  Grape juice

  Egg

  Sucrose
• What is the negative control?

  water
• What is the color of the negative solution?

  blue
• What is the positive control?

  glucose
• What is the color of the positive solution?

  red
• A blue precipitate means that the amount of reducing sugar is

  none
• A red precipitate means that the amount of reducing sugar is

  high
• An orange precipitate means that the amount of reducing sugar is

  medium
• True or False: Negative control is designated for negative result because water contains reducing sugar.

  False
• True or False: Positive control contains glucose, a reducing sugar, so we can be sure of a positive result.

  True
• How many mL of Benedicts’ s reagent is placed in each test tube?

  1
• How many test tubes are used in the experiment?

  8
• How many drops of each samples are added in the test tubes?

  2 to 3
• How long are the test tubes heated in the water bath?

  3 mins
• Which samples showed a positive result?

  Glucose

  Milk

  Grape juice
• Which samples showed a negative result?

  Water

  Groundnut oil

  Egg white

  Sucrose
• Which sample showed a green precipitate?

  wheat flour
• A green precipitate means that the amount of reducing sugar is

  low
• The _ reduces copper (Cu2+) in the benedict’s reagent to form cuprous oxide(Cu+)

  aldehyde
• True or False: Non-reducing sugar such as sucrose do not contain an aldehyde group in solution therefore, it cannot reduce a copper ion in the benedict’s reagent.

  True