| The extrusion and extrudate properties measured include expansion indices (or puff indices), bulk density, residence time, solid density, moisture content, maximum stress, water solubility index (WSI), water absorption index (WAI), extruder output, crispness and color. The ranges of the three variables considered were 100 - 160°C for barrel temperature, 100 - 200rpm for screw speed, and 15 - 25% for feed moisture content (w.b.). The density of extrudate measured varied between 176kg/m3 and 1100kg/m3 for the extrusion variables considered. The moisture content of the dry extrudate is between 6% and 7.5% with the mean value of 6.75%. Using the experimental results, predictive equations were developed to relate the influence of processing parameters on the... |
