Product Temperature Response of a Locally Developed Extruder to Maize Processing

Product temperature is a very important system parameter as well as an indicator of extrusion process. In this study, the product temperature response of a single screw extruder developed locally was investigated for the extrusion process of the flour and starch of maize. A factorial experiment in completely randomized design was employed to study the effect of extrusion variables: feed moisture (30, 40, 50 %), extruder temperature (40, 70, 100oC) built up by varying the duration of sampling and screw speed (100, 150, 200 rpm) on product temperature. Product temperature increased with increase in duration of operation. A maximum temperature of 150oC was attained in 30 minutes through viscous dissipation Also, the study revealed that the product temperature is strongly related to the extrusion process parameters under study and the proximate composition of samples. Also, Product temperature increased at 100 and 150 rpm but decreased at 200 rpm. The equations relating the various dependent and independent variables were established to predict the extruder’s performance for maize processing. Quadratic coefficients fit the extrusion data very well, better than linear models.