Food Tests Required Practical

Question 1

How do you test for lipids?(7 steps)

Answer 1

1) put some food in test tube
2) add some drops of ethanol
3) shake test tube and leave for 1 minute
4) pour solution into test tube of water
5) If the ethanol solution gives a cloudy white layer on top of the water, lipids are present
6) record in table
7) repeat for other food

Question 2

How do you test for protein?(5 steps)

Answer 2

1) place food in test tube
2) add 1cm cubed of Biuret reagent
3) if Biuret reagent turns purple then protein is present
4) record in table
5) repeat for other food

Question 3

How do you test for starch? (5 steps)

Answer 3

1) place some food on spotting tile
2) add some drops of iodine solution to the food
3) if the iodine turns blue/black starch is present
4) record in results table
5) repeat for other food

Question 4

How do you test for sugar?(6 steps)

Answer 4

1) put some food in test tube
2) add Benedict’s solution to cover all food
3) place tube in warm water bath for 10mins
4) if solution turns brick red, sugar is present
5) record in table
6 repeat for other food

Question 5

What colour is iodine solution originally?

Answer 5

Yellow/red

Question 6

What colour does iodine solution become if starch is present?

Answer 6

Blue/black

Question 7

What colour is Benedict’s solution originally?

Answer 7

Blue

Question 8

What colour does Benedict’s solution become if sugar is present?

Answer 8

Brick red

Question 9

What colour is ethanol originally?

Answer 9

Colourless

Question 10

What happens to ethanol when there are lipids present?

Answer 10

Cloudy layer on water

Question 11

What colour is Biuret reagent originally?

Answer 11

Blue

Question 12

What colour does Biuret regeant become if proteins are present?

Answer 12

Purple