Required Practical - Food test

Question 1

What is the point of the practical?

Answer 1

To find out if sugars, starch and/or proteins are in foods

Question 2

What chemical do you use to test for starch?

Answer 2

Iodine solution

Question 3

How do you test for starch?

Answer 3

add the iodine solution directly to the substance (liquid or solid form).

Question 4

What colour result signifies starch is present?

Answer 4

Blue/Black

Question 5

What chemical do you use to test for protein?

Answer 5

Biuret solution

Question 6

What colour result signifies protein is present?

Answer 6

Purple

Question 7

What chemical do you use to test for glucose?

Answer 7

Benedicts solution

Question 8

How do you test for glucose?

Answer 8

• Add benedicts solution

- Heat for two minutes in a water bath at boiling point and looking for a colour change

Question 9

What colour result signifies glucose is present?

Answer 9

Brick red (green/yellow/orange if less sugar is present)

Question 10

What chemical do you use to test for lipids?

Answer 10

Ethanol

Question 11

How do you test for a lipid?

Answer 11

• Add ethanol and shake thoroughly

- Then add water and look for a colour change

Question 12

What colour will it be if a lipid is present?

Answer 12

Cloudy/milky

Question 13

What is a lipid?

Answer 13

fatty acids

Question 14

Why shouldn’t you heat a solution too long?

Answer 14

As the starch in a solution might break down and test positive for glucose