Food Tests Starch + Sugars

Question 1

How do we make the food solution?

Answer 1

1) Take the food sample and grind this with distilled water using a mortar and pestle to make a paste.
2) Transfer the paste into a beaker and add more distilled water
+ Stir so that the chemicals in the food dissolve in the water.

3) Filter the solution to remove suspended food particles.

Question 2

How do we test for starch?

Answer 2

• Place 2cm^3 of food solution into a test tube.
• Add a Few drops of iodine solution.
• If starch is present:
• Iodine will turn blue or black.
• No starch= remains orange.

Question 3

How do we test for sugars?

Answer 3

• Place 2cm^3 of food solution into test tube.
• Add 10 drops of iodine solution (blue).
• Place test tube into a beaker + half fill the beaker with hot water from a kettle.
• Leave for 5 minutes.
  Results:
• ## Sugar is present= Benedicts solution change colour.

Question 4

What does the colours of benedicts solution tells us?

Answer 4

• Approximation in the amount of sugar.
  Green= Small Amount of sugar.
  Yellow= More sugar present.
  Red= Lots of sugar present.

Question 5

When does the benedicts test work?

Answer 5

• Only for reducing sugars e.g Glucose.
• ## Not for non reducing sugars such as Sucrose.