food tests practical

Cards (18)

what does the biuret test, test for? 
protein
what does the benedict's test, test for? 
sugars (reducing sugars)
what is the iodine test testing for? 
starch
what does the sudan 111 test, test for? 
Lipids
what colour does the biuret test change to if protein is present? 
pink/purple (from blue)
what colour does the benedict test change to if sugars present? 
yellow/green/brick red (from blue) depending on concentration
what colour does the iodine test turn if start is present? 
blue/black (from orange)
what happens to the Sudan 111 test is lipids are present? 
a red layer separates forms at the top (the Sudan 111 solution stains the lipids)
how much benedict's solution do you add to the test tube? 
10 drops
what temperature should the water bath be in the benedict test? 
75 degrees celsius
how much food sample do you need for the benedict test. 
5cm cubed
how long should the test tube be in the water bath (benedict test)? 
5 minutes
how much food sample do you need for the biuret test? 
2cm cubed
how much biuret solution do you need for the test? 
2cm cubed
how much iodine do you need for the test? 
a few drops
how much food sample do you need for the iodine test? 
5cm cubed
how much food sample do you need for the sudan 111 test? 
5cm cubed (unfiltered)
how much sudan 111 stain solution do you need for the test? 
3 drops