Thermoplastic extrusion-the mechanism of the formation of extrudate structure and properties

Systems processed by thermoplastic extrusion can be regarded as heterophase polymer melts of incompatible water‐plasticized biopolymers. In the process of thermoplastic extrusion, proteins and polysaccharides are melted at high pressure and temperature below the temperature region of their thermal decomposition. Dispersed particles of these systems can be deformed in flow. The mixed‐melt anisotropic structure, formed in flow, is fixed by rapid conversion of the melt jet that lets the extruder die from a viscous state to a rubber‐like state and then to a glassy state caused by cooling and drying. Incompatibility of proteins and polysaccharides in their water‐plasticized melt mixtures impacts on structure formation and texturization during thermoplastic extrusion.