P1: Food Tests

Question 1

What do you use to test for sugars?

Answer 1

Benedict’s Solution.

Question 2

What do you use to test for starch?

Answer 2

Iodine

Question 2

What do you use to test for fats?

Answer 2

Ethanol and distilled water.

Question 2

What do you use to test for proteins?

Answer 2

Biuret reagent

Question 3

How do you test for fats?

Answer 3

Add ethanol and water to the substance, and shake. A white cloudy emulsion will form if lipids are present.

Question 4

How do you test for sugars?

Answer 4

Add Benedict’s solution to the substance, and put in a water bath. The colour will change from blue to green to yellow to orange to brick red.

Question 5

How do you test for starch?

Answer 5

Grind food into a powder with water, filter out the water, and add a drop of iodine on. Food containing the starch will turn a blue-black colour.

Question 6

How do you test for proteins?

Answer 6

Put food in solution, add 1cm^3 of biuret solution to the food.

Question 7

Describe the colour change of biuret solution.

Answer 7

Changes from blue to violet.

Question 8

Describe the colour change of Benedict’s solution.

Answer 8

Blue, to green, yellow, orange to brick-red

Question 9

Describe the colour change of iodine.

Answer 9

Orange brown to blue black.

Question 10

Describe the colour change of ethanol.

Answer 10

No colour change. Cloudy emulsion forms.