Abstract: Presented are compositions of reduced molecular weight galactomannans, particularly guar gum, which have been oxidized by the enzyme galactose oxidase. Further, the invention relates to a process for enzymatically reducing the molecular weight of a galactomannan wherein the galactomannan is simultaneously or subsequently oxidized using galactose oxidase, optionally in combination with other enzymes including peroxidases and or catalases. This process enables production of high concentrations of oxidized galactomannans, which have particular use in the paper making industry.