1. Food tests Flashcards
1
Q
Starch
A
Add 5 drops of iodine to the sample
Positive result = brown to blue black
2
Q
Benedicts test for reducing sugar
A
Add 1ml Benedicts reagent to sample
Heat to 95°C for 3 minutes in water bath
Positive result = Brick red precipitate forms
3
Q
Non reducing sugar test
A
Carry out benedicts test and get a negative result
Add dilute Hydrochloric acid to sample and boil
Netrualise with NaHCO3 until it stops fizzing
Add benedicts reagent and heat
Positive result - blue before hydrolysis, brick red after
4
Q
Emulsion test for lipids
A
Dissolve sample in ethanol
Add water
Positive result - White emulsion forms
5
Q
Biuret test for proteins
A
Add biuret reagent
Positive result - pale blue to lilac
