Effect of Some Extrusion Variables on Rheological Properties and Physicochemical Changes of Cornmeal Extruded by Twin Screw Extruder

• Main Authors: Y.K. Chang, f. Martínez-Bustos, h. Lara
• Format: Article
• Language: English
• Published: Brazilian Society of Chemical Engineering 1998-12-01
• Series: Brazilian Journal of Chemical Engineering
• Subjects: Extrusion variables; rheological properties; screw speed
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-66321998000400006

The effect of extrusion variables, such as barrel temperature (100 to 170ºC), feed rate (100 to 500 g/min), feed moisture (20 to 40 g/100 g wet basis), screw speed rate (from 100 to 500 rpm), and slit die rheometer configuration (0.15 and 0.30 cm height) were studied using a co-rotating intermeshing twin-screw extruder coupled to a slit die rheometer on the rheological properties of yellow cornmeal. An increase in feed rate decreased WAI and WSI, but increased the viscosity values. The temperature interacts strongly with screw speed in affecting the WSI. The most important factor in starch degradation was the screw speed. Increasing the screw speed completely modifies the organised structure of starch (crystalline region).