biological molecules test Flashcards
what is the test for starch?
iodine solution
explain the test for starch
- place food sample on a spotting tile
- add a few drops of iodine solution to the sample
- blue - black colour indicates starch
what is the test for glucose / reducing sugars?
benedicts solution
explain the test for glucose / reducing sugars?
- place food sample in a boiling tube
- add benedict’s solution to the sample of food in solution
- place in a water bath at 80•c for 5 minutes
- a change from blue to brick red if present
(if green, yellow or orange means less sugar present)
what is the test for protein?
biuret test
explain the test for protein
- place food sample in a boiling tube
- add enough biuret solution for colour to be pale blue
- if protein is present colour will change to mauve / purple
what is the test for lipids?
ethanol test
explain the test for lipids?
- Place food sample in a test tube
- Add small amount of ethanol and shake to dissolve any lipid in the alcohol.
- Add equal volume of water
- Cloudy white colour ( emulsion will form) indication presence of lipid
benedicts solution is used to test for
reducing sugars (glucose0
benedicts solution colour change
blue to brick red
how do I remember benedicts solution
christmas sugar
iodine is used to test for
starch
iodine solution colour change
orange to blue-black
how do I remember iodine
bumblebee
biuret is used to test for
protein
biuret solution colour change
(light)blue to pale purple
how do I remember biuret
snowflakes
(et) proTEin biurET
emulsion is used to test for
lipids
emulsion colour change
colourless to a cloudy white emulsion
how do I remember emulsion
snowing
