Food Tests

Question 1

How do you make a food sample?

Answer 1

• crush food using pestle and mortar
• add distilled water
• stir with a glass rod until some is dissolved
• filter out large pieces of food using filter paper

Question 2

What is the test for starch?

Answer 2

Iodine test
- 5cm3 of food sample
- add several drops of iodine until solution turns brown / orange colour
- shake
- if blue / black, starch is present

Question 3

What is the test for lipids?

Answer 3

Sudan III test
- 5cm3 of food sample, add 3 drops of Sudan III solution , gentle shake, if present red layer on top

Question 4

What is the test for proteins?

Answer 4

Biuret
- add 2cm3 of biuret to 2cm3 of food sample
- shake
- if present solution turns pink / purple

Question 5

What is the test for sugars?

Answer 5

Benedict’s
- 5cm3 of food sample
- prep water bath at 75’C
- add 10 drops of Benedict’s to solution
- put test tub win to water bath
- leave for 5 mins
- if sugar present solution turn yellow / green / brick red depending on concentration

Question 6

How much food sample is used for almost every food test?

Answer 6

5cm3- except for protein which uses 2cm3