Food Tests

Question 1

How do you complete the food test for lipids

Answer 1

1 Place a small amount of food into a test tube.
2 Add a few drops of ethanol to the test tube.
3 Shake the test tube and leave for 1 minute.
4 Pour the solution into a test tube of water.
5 Ethanol added to a solution gives a cloudy white layer if
a lipid is present.
6 Record your result in the results table.

Question 2

How do you complete the food test for protein

Answer 2

Place a small amount of food in a test tube.
2 Add 1 cm
3 of Biuret reagent.
4 Blue Biuret reagent turns purple if a protein is present.
5 Record your result in the results table.

Question 3

How do you complete food test for sugar

Answer 3

1 Place a small amount of food in a test tube.
2 Add enough Benedict’s solution to cover the food.
3 Place the test tube in a warm water bath for 10 minutes.
4 Blue Benedict’s solution turns brick red on heating if a
sugar such as glucose is present.
5 Record your result in the results table.

Question 4

How do you complete the food test for starch

Answer 4

1 Place a small amount of food on the spotting tile.
2 Add a few drops of iodine solution to the food on the
spotting tile.
3 Yellow–red iodine solution turns blue–black if starch is
present.

Question 5

What colour will the food go if starch is present

Answer 5

Black

Yes or no

Question 6

What colour will the food go if sugar is present

Answer 6

Orange

Question 7

What colour will the food go if protein is present

Answer 7

Blue/purple

Question 8

What colour will the food go if lipids are present

Answer 8

Cloudy water