4. Conclusions
The functional properties of paper coated with caseinate and caseinate/chitosan bilayer coatings were investigated as a function of coating weight, caseinate contents, and coating application methods. At high caseinate content, caseinate/chitosan bilayer coatings prepared by application of chitosan as a second layer on wet caseinate-coated paper showed lower WVP than the pure caseinate-coated paper. Tensile properties of coated papers were shown to be mainly dependent on the coating weight. The application of a chitosan layer on the dried preformed caseinate coatings provided paper with the highest water vapor barrier and mechanical properties and the resulting caseinate/chitosan-coated papers showed good appearance, flexibility, and adhesion between the bilayer coating and the cellulosic substrate. These bilayer systems seemed to be appropriate coating materials for paper-packaging materials.