Fructose contains a keto group, yet it reduces Fehling solution and Tollen's reagent. Why ?

Fructose although contains a ketone group yet it acts as a reducing sugar. This is explained by the formation of glucose from fructose by enolisation. Enolisation results in the formation of glucose from fructose and vice versa. (Lobry de Bruyn Van Ekenstein rearrangement).