Modeling of twin-screw extrusion cooking of corn meal and sugar beet fiber mixtures

A statistical model was established for extrusion cooking of corn meal and sugar beet fiber mixtures in a twin-extruder. The operational variables included screw speed of the extruder, addition level of sugar beet fiber and fiber particle size. Specific mechanical energy (SME) input, product temperature (T), pressure before die (DP) and gelatinized starch content (GS) were measured and used to characterize the physical and chemical properties of extrudates. The results showed that these predictor variables could explain 79-96% of the variations in product length, diameter, specific volume, breaking strength and water absorption index. Color attributes of the product also depended on the fiber particle size. It showed that the empirical model proposed by Meuser and coworkers is applicable to the complex food system.