Starch and sucrose both belong to non-reducing sugars, these two substances can be hydrolyzed to reducing sugars catalyzed by amylase, reducing sugars are able to undergo a redox reaction with Ferrin's reagent to produce a brick-red cuprous oxide precipitate, and in the course of the experiment, too much acid or too much alkali will affect the activity of amylase.

Amylase is a general term for enzymes that hydrolyze starch and glycogen, usually through amylase-catalyzed hydrolysis of starch slurry on fabrics.