Co-extrusion of corn meal and polydextrose for making high fiber snack food: effects of extrusion screw speed on the product quality
High fiber snack foods are attracting consumers’ attention due to their health benefits. In this research, corn meal and polydextrose are co-extruded with a twin-screw extruder and the screw speed is varied from 150 to 190 rpm. The objective of the research is to evaluate the effects of screw speed on the product quality. As the screw speed is increased, the expansion ratio and crispness of the fried extrudate are enhanced while the bulk density and hardness are reduced. Increase in screw speed results in increased water absorption index and water solubility index of the product. As the screw speed is increased, the mechanical energy of the extrusion process is also increased. The screw speed has significant correlation with the expansion index, bulk density and texture properties of the fried extrudate (p < 0.05).