Carbohydrates - Reducing Sugars
Reducing sugars are those sugars capable of reducing copper (II) ions in a solution to copper (I) oxide. The reducing sugars include:
(1) all aldoses (whether in the straight chain or cyclic form)
(2) 
-hydroxyketoses. An -hydroxyketose contains the group below. Fructose is an example.
(3) disaccharides that contain a hemiacetal or hemiketal. Maltose (left) is a reducing sugar. Sucrose (right) is not.
Continue and read about carbohydrate tests.
