Define Reaction for Nelson-Somogyi Method?

The reagent used for enolization contains alkaline solution of cupric sulfate and Rochelle salt. Rochelle salt in the reagent prevents precipitation of cupric hydroxide by forming soluble dissociable complex with cupric ions. This complex provides a continuous supply of cupric ions for reaction with the enediol form of sugar. Sodium sulfate is included in the reaction mixture to minimize the entry of atmospheric oxygen into the solution that would cause reoxidation of cuprous oxide.