Food tests

Test for starch

Add Iodine & it goes blue black

Test for lipids

Emulsion test

Test for Protein

Biuret test

Test for reducing sugars

Benedicts test

Test for a non reducing sugar

Basically just a longer Benedict's a standard Benedicts test must be performed first

Process for emulsion test

Dissolve lipid in alcohol and add water, if positive it forms a milky white emulsion

Process for Biurete

Dissolve sample in water and add Biuret solution, of protein present it turns from blue to purple

Temperature for Benedict’s

Over 60c

Process for Benedict’s test

Dissolve sample, add equal Benedict’s solution, heat for 5 mins, if reducing sugar present turns from blue to brick red

Non reducing sugar process

After Benedict’s has come back negative dissolve new sample in water then add equal vol dilute HCl, heat for 5 min, neutralise with sodium bicarbonate till stops fizzing, add Benedict’s solution, heat form5 mins. Of positive turns from blue to brick red/orange

What is the HCl for

To hydrolyse bonds between dipepteides