Biochemical Tests

Question 1

Test for starch?

Answer 1

Add iodine/ potassium iodide solution
Yellow-> blue/black

Question 2

Test for reducing sugars e.g. all monosaccharides and maltose?

Answer 2

Add Benedict’s reagent
Heat to 80 degrees (water bath)
Blue -> orange/green

Question 3

Test for non-reducing sugars (some disaccharides)?

Answer 3

Boil in hydrochloric acid (to hydrolyse the disaccharide into its monosaccharides)
Add hydrogen carbonate solution (to neutralise)
Add Benedict’s reagent
Heat to 80 degrees
Blue -> orange/ green