biological molecules test Flashcards
1
Q
what is the test for starch?
A
iodine solution
2
Q
explain the test for starch
A
- place food sample on a spotting tile
- add a few drops of iodine solution to the sample
- blue - black colour indicates starch
3
Q
what is the test for glucose / reducing sugars?
A
benedicts solution
4
Q
explain the test for glucose / reducing sugars?
A
- 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)
5
Q
what is the test for protein?
A
biuret test
6
Q
explain the test for protein
A
- 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
7
Q
what is the test for lipids?
A
ethanol test
8
Q
explain the test for lipids?
A
- 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
9
Q
benedicts solution is used to test for
A
reducing sugars (glucose0
10
Q
benedicts solution colour change
A
blue to brick red
11
Q
how do I remember benedicts solution
A
christmas sugar
12
Q
iodine is used to test for
A
starch
13
Q
iodine solution colour change
A
orange to blue-black
14
Q
how do I remember iodine
A
bumblebee
15
Q
biuret is used to test for
A
protein
