Modeling product quality during twin-screw food extrusion

The product quality attributes PQA (bulk density, color b index, and moistu re content), of extrudates produced using a twin-screw food extruder with t wo different screw configurations (A and B) were evaluated and analyzed as a function of operating and process variables. Relationships were obtained using multiple linear regression methods. Results showed that PQA became le ss sensitive to changes in operating variables when using screw configurati on B (two reverse kneading paddles added to the shear section of the extrud er). Models of on-line measured PQA (extrudate moisture and color b index) could be used in the design of extrusion process control systems.