How do you test for non-reducing sugars?

Answer 1

Disaccharides such as sucrose are non- reducing sugars. In order to detect non-reducing sugars, they must be broken down into monomer form by hydrolysis 1.) If the sample isn't already in liquid form grind it up in water. 2.) Add 2cm3(cubed) of the food sample to a test tube with 2cm of benedict's reagent 3.) (gently) boil in a water bath for 5 mins 4.)If a NON-REDUCING sugar is present then the solution will remains BLUE 5.)In this case another 2cm3 of the food sample to 2cm3 of (dilute) hydrochloric acid in a test tube(as the hydrochloric acid hydrolases the disaccharide into its monomer constituents .i.e. sucrose --> glucose + fructose) 6.) (Slowly) add sodium hydrogencarbonate to the test tube(to neutalise the hydrochloric acid as Benedict's reagent can't work in acidic conditions) 7.)Now re-test the solution by heating it with the 2cm3 of Benedict's reagent for 5 mins, this time the solution should turn from blue to orange-brown/brick red because reducing sugars are present(.i.e. glucose and fructose)due to the hydrolysis of the disaccharide (sucrose) Hope this helps :)

Answer 2

The blue color of the solution remains(if you are using Benedict's solution).