Effect of process variables and monoglycerides on extrusion of maize grits using two sizes of extruder

The effect of moisture, temperature and addition of monoglycerides (MG) on the extrusion behaviour of maize gi its was studied using laboratory (MPF-19) and pilot scale (MPF-50) extruders, which were operated under conditions of scale lip by throughput and die size. The extruder responses of pressure, torque and SME and the extrudate proper-ties of expansion and water solubility and absorption indices were measured and compared in the two scales of extruder: Die pressure and torque (expressed as a percentage of maximum) of the MPF-50 extruder were higher compared to those of the MPF-19 extruder; however; the reverse was true for SME, expansion and water solubility index of extrudates. However the general applicability of these results may depend on feedstock particle size because of scale up of the screw-barrel gap. (C) 1998 Elsevier Science Limited All rights reserved.