Process for the separation of lactulose

The invention relates to a process for the separation of lactulose from a mixture of lactulose and lactose in the presence of a weak acid capable of reversibly forming a complex with lactulose, by using an electrodialysis equipment including an anode and a cathode compartment separated by a plurality of parallel compartments comprising alternating diluate and concentrate compartments, wherein adjacent compartments are separated from each other by permselective membranes; which process is characterized by: (a) continuously passing an alkaline aqueous solution of lactulose, lactose and said complex forming weak acid through the diluate compartments, each diluate compartment being bound by a bipolar membrane at its lateral side facing the cathode and at its opposite lateral side by an anion exchange membrane, separating said compartment from its adjacent concentrate compartment; (b) continuously passing a carrier fluid through the concentrate compartments, each concentrate compartment being bound at its lateral side facing the anode by a bipolar membrane and at its opposite lateral side by said anion exchange membrane; and (c) maintaining an electric potential between anode and cathode which transports complexed lactulose preferentially to lactose from said diluate compartments to said concentrate compartments, in order to enrich the carrier fluid with complexed lactulose. The invention further relates to an electrodialysis equipment for use in the above process.