food tests - organisation - biology practical

Question 1

To test for starch, what chemical should be used?

Answer 1

iodine solution

Question 2

If iodine is present, what colour will it change into?

Answer 2

from brownie orange to black or blue-black

Question 3

To test for protein, what chemical should be used?

Answer 3

Biuret solution

Question 4

if protein is present, what colour will it change into?

Answer 4

From blue to purple

Question 5

To test for sugars, what chemical should be used?

Answer 5

Benedicts solution

Question 6

How many drops of benedicts solution should be added?

How many degrees should the water bath be heated?

Answer 6

10 drops

75*oC

Question 7

If sugar is present, what colour will it change into?

Answer 7

From blue to brick-red, yellow or green

Question 8

To test for lipids, what chemical should be used?

Answer 8

Sudan III solution

Question 9

how many drops of Sudan III do you add to the food sample?

Answer 9

3 drops

Question 10

What is special about the Sudan III sample?
what does this mean and what colour does it change into?

Answer 10

it stains the lipids meaning that the insoluble separates if lipids is present
The top then changes brick-red