Influence of independent extrusion variables on temperature profile in extruder barrel

Abstract

Extrusion technology is commonly used in fish feed production. In cooking zone of the extruder barrel, sufficient energy is imparted to gelatinize starch and denature proteins. Time in which material will be exposed to high temperatures and pressures depends of the time that material spends in the cooking zone. Length of the cooking zone can be varied by changing independent extrusion variables. In this investigation, screw speed, amount of added oil and total area of die openings were varied. The most severe conditions of 0% of added oil, screw speed of 420 rpm, and 50 mm2 of total area of die openings, resulted in the highest temperatures at measuring points (T1 = 102.6°C, T2 = 104.0°C, T3 = 110.3°C, T4 = 118.8°C). It can be concluded that by changing independent extrusion variables, temperature profile in the barrel can be modified in order to achieve optimal extrusion conditions.

Keywords

• extrusion cooking
• temperature profile
• fish feed