PAG 09 - 9.4: Emulsion Test

What tests must you carry out to find out whether a sample contains lipid?

An emulsion test

What is the list of apparatus/ equipment needed?

What are the 5 simple steps for carrying out this test?

1 - Place food sample in a test tube

2 - Add 2cm3 of ethanol / twice as much ethanol, and shake it thoroughly

3 - Allow it to settle

4 - Decant into distilled water/ add 2cm3 of distilled water

5 - If lipids are present, the water goes from clear to cloudy

How/ why do these emulsion from?

They form because lipids dissolve in ethanol but not in water. As a result, the lipids form droplets in water, creating an emulsion

What is the positive result of lipids in an emulsion test?

The sample turns into a milky white colour / and emulsion forms

What is the negative result of lipids in an emulsion test?

The sample remains clear/ colourless