Food Tests RPA

Question 1

What solution tests for starch

Answer 1

Iodine

Question 2

What colour iodine solution goes from and to

Answer 2

Orange to black

Question 3

How to test for glucose/ reducing sugars

Answer 3

Add food sample to test tube
Add a few drops of Benedict’s solution with a pipette
Leave in a hot water bath for a few minutes
If glucose is present the solution will turn brick red

Question 4

Colour change for Benedict’s solution

Answer 4

Blue to brick red

Question 5

How to test for protein

Answer 5

Add food sample to test tube
Add a few drops of Biuret solution
If protein is present solution will turn purple

Question 6

Colour change for biuret solution

Answer 6

Blue to purple

Question 7

How to test for lipids

Answer 7

Add food sample to test tube
Add a few drops of distilled water and ethanol
Gently shake
If lipids are present a white emulsion forms

Question 8

2 Safety precautions

Answer 8

Wear safety goggles (some of the solutions e.g iodine is an irritant)
Keep ethanol away from flames as it is flammable

Question 9

How to prepare food sample before testing

Answer 9

Grind with pestle and mortar
Add distilled water
Filter with funnel and filter paper (except for lipids as they stick to the filter paper)

Question 10

For which test should we gently shake the test tube

Answer 10

Lipids (using ethanol)