Types of Food Processing Equipment

8. Extruders

In extrusion cooking a mix of ingedients (usually a flour and water) are forced under pressure and heat through a metal barrel and out through a shaped hole in a metal plate (called a die). The process considerably changes texture and nature of the original ingredient, and gives it a new shape. The resulting product is then cut into shape and sometimes baked or dried afterwards. Although there are piston and roller-type extruders, the most often used type of extruder in the food industry is the screw extruders, which can propel the pasty product forward with a single screw or twin screws.

Schematic representation of food extrusion cooking process

Image source: Oonsivilai, Anant & Oonsivilai, Ratchadaporn. (2008). Parameter estimation of frequency response twin-screw food extrusion process using genetic algorithms. WSEAS TRANSACTIONS on SYSTEMS. 7. 1207-1217.