Required practical 4: Food tests

Question 1

What should be done to the food sample before the test?

Answer 1

Should be grinded up with distilled water in a pestle and mortar until it is a paste.
Then transfer to a beaker and add more distilled water, stir so the chemicals in the food dissolve into water. Finally filter the solution to remove left over food particles.

Question 2

When testing for glucose what else is required to see if it’s present?

Answer 2

Heat, place test tube in a larger beaker with hot water for 5 minutes

Question 3

What should be added when testing for starch, and if present what colour will it go?

Answer 3

Iodine and it will turn blue/black

Question 4

What is added to test for glucose, and what colour will it go if glucose is present?

Answer 4

Benedicts solution, and will go green if there is a small amount of glucose and yellow if there is more but red if a lot

Question 5

When testing for protien what is added and what colour will it go if present?

Answer 5

Biuret solution and will change to purple or lilac colour

Question 6

What is done different to food samples when testing for lipids and why?

Answer 6

It shouldnt be filtered because lipid molecules can stick to filter paper

Question 7

What is added when testing for lipids and what colour should it go?

Answer 7

Ethanol and will go white/cloudy if present