Biochemical tests
what is the test for lipids?
emulsion test
describe the first step of the emulsion test
add food sample to test tube with 2cm3 of ethanol
describe the second step of the emulsion test
shake the ethanol and food sample, then add 2cm3 of distilled water and shake again
what is the positive result for the emulsion test?
a milky white emulsion formed
what is the test for proteins
biuret solution
what is the first step of the proteins test?
2cm3 of water and 2cm3 of food sample in a test tube
what is the second step of the protein test
drop biuret down the side of the test tube and shake carefully
positive result for biuret
lilac purple colour change
negative result for biuret
bright blue solution