Food tests

Question 1

What is the test for starch?

Answer 1

Iodine test

Question 2

What is the test for lipids?

Answer 2

Emulsion test

Question 3

What is the test for proteins?

Answer 3

Biuret test

Question 4

What is the test for reducing sugars?

Answer 4

Benedicts test

Question 5

What is the test for NON reducing sugars? (any sugar that gives negative benedicts test)

Answer 5

Acid hydrolysis

Question 6

Whats the method + result for the iodine test?

Answer 6

1. Add sample to dimple in spotting tile
2. Add a few drops of iodine in KI solution

Result: Blue/black colour

Question 7

What is the method + result for the emulsion test?

Answer 7

1. Add ethanol to test tube
2. Add sample + shake vigorously to dissolve
3. Add cold water

Result: Cloudy emulsion

Question 8

Whats the method + result for biuret test?

Answer 8

1. Add sample solution to test tube
2. Add biuret solution
3. Observe colour change

Result: Purple/lilac colour

Question 9

Whats the method + result for the benedicts test?

Answer 9

1. Add sample to test tube
2. Add benedicts reagent
3. Heat in waterbath + observe colour change

Result: Brick red precipitate, green/red colour

Question 10

Whats the method + result for the acid hydrolysis test?

Answer 10

1. Add sample + HCL to test tube
2. Boil in waterbath
3. Neautralise with NaHCO3 powder (effervescence will occur)
4. Check pH with indicator paper
5. Carry out benedicts test

Result: Brick red precipitate, green/red

Question 11

How do u work out uncertainty?

Answer 11

Value of smallest division / 2