Chitosan-based Maillard products for enzyme immobilization in multilayers structure: Its application in electrochemical sensing

•Water-soluble chitosans were obtained by Maillard reaction with glucose or lactose.•Chit derivatives enable immobilization of glucose oxidase and lactate oxidase.•A highly efficient glucose biosensor was obtained by assembling G-Chit and GOx.•The analytical response was tested in milk samples with negligible matrix effects.