Mechanical and thermomechanical properties of films based on whey proteinsas affected by plasticizer and crosslinking agents

The plasticizing effect of glycerol and the crosslinking effect of formalde hyde and calcium chloride on the mechanical and thermomechanical properties of whey protein-based films were studied. Increased plasticizer content in creased the percentage of solubility in water and decreased the mechanical resistance, apparent Young modulus, and glass transition temperature of the whey protein films. The incorporation of formaldehyde as a crosslinking ag ent enhanced the mechanical properties and insolubility behavior and increa sed the glass transition temperature. The addition of a low concentration o f CaCl2 in the film formulation did not significantly effect the functional properties of the films. These changes could be partially explained by the modifications in cohesion between the protein chains because of changes in type, intensity, and distribution of the intermolecular interactions.