food tests Flashcards
1
Q
what is benedict’s solution used for?
A
finding glucose/reducing sugars
2
Q
what is iodine solution used to test for?
A
starch
3
Q
what is Biuret solution used to test for?
A
protein
4
Q
what is emulsion the test for?
A
lipids
5
Q
what colour change occurs in iodine solution when it tests for starch?
A
orange -> blue/black
6
Q
what colour change occurs in benedict’s solution when it tests for glucose?
A
blue -> red, orange, green (red is highest concentration of glucose, green is lowest)
7
Q
what colour change occurs in Biuret solution when it tests for protein?
A
blue -> pale purple
8
Q
what happens when lipids are present in the emulsion test?
A
the solution turns a cloudy white colour, caused by an emulsion forming
9
Q
how do you test for glucose/reducing sugars?
A
- add benedict’s solution to a sample of food solution
- place in a water bath at 80 degrees C for 5 mins
- if a reducing sugar is present, it will turn from blue brick red. it will go orange/green if a lower concentration of it is present.
