Food Tests

Question 1

What is used to test for starch?

Answer 1

Iodine solution.

Question 2

What is a positive result for starch?

Answer 2

Blue-black colour.

Question 3

What is used to test for reducing sugars?

Answer 3

Benedict’s reagent and heating in a water bath for 2–3 minutes.

Question 4

What is a positive result for reducing sugars?

Answer 4

Colour changes from blue → green → yellow → orange → brick red (depending on sugar concentration).

Question 5

What is a negative result for reducing sugars?

Answer 5

Solution remains blue.

Question 6

What is used to test for proteins?

Answer 6

Biuret reagent.

Question 7

What is a positive result for proteins?

Answer 7

Purple or lilac colour.

Question 8

What is a negative result for proteins?

Answer 8

Solution remains blue.

Question 9

What is the test for fats (lipids)?

Answer 9

Emulsion test – add ethanol, then water.

Question 10

What is a positive result for fats?

Answer 10

Milky-white emulsion appears.

Question 11

What is used to test for Vitamin C?

Answer 11

DCPIP solution.

Question 12

What is a positive result for Vitamin C?

Answer 12

DCPIP blue colour disappears.