Novel chitosan–pectin composite membranes with enhanced strength, hydrophilicity and controllable disintegration

Novel composite porous membranes made of basic and acidic polysaccharides (i.e. chitosan and pectin) were developed. Three types of chitosan/pectin composite membranes were fabricated: PEC-type (by polyelectrolyte complex (PEC) formation between chitosan and pectin); PEC/Ca-type (by PEC and calcium ion-mediated ionic crosslinking toward pectin); and PEC/covalent-type membranes (by PEC and EDC/NHS-mediated covalent bond). Tensile strengths (about fourfold that of pure chitosan membranes), hydrophilicity and water uptake capability of the composite membranes were significantly greater than membranes composed of chitosan or pectin only. Such composite membranes had faster disintegration rates which could be controlled by the content of pectin. Addition of calcium ions or EDC/NHS further increased the tensile strengths of the composite membranes (by about 1.5-fold) and also changed the profile of disintegration. Such chitosan/pectin composite membranes, due to their enhanced strength, hydrophilicity and controllable disintegration behavior, have potential as edible sponges or disintegrant carrying food or drug.