Tests For Foods Flashcards
1
Q
Test for proteins?
A
Biuret’s test
2
Q
What colour is biuret’s solution?
A
Pale blue
3
Q
What colour does biuret’s solution turn if protein is present?
A
Purple/mauve
4
Q
Test for lipids?
A
Emulsion test
5
Q
Describe the steps for test for lipids and explain why each is done.
A
Add sample to ethanol- dissolve in organic solvent
Add water to solution- ethanol is soluble in water, so lipid falls out and forms micelles (small droplets) which reflect light and appear white
6
Q
Test for starch?
A
Iodine dissolves in potassium iodide
7
Q
What colour is iodine solution?
A
Brown/orange
8
Q
What colour does iodine solution change to if starch is present?
A
Blue/black
