Food Extrusion

Food extrusion is a food processing technique that forces soft mixed ingredients through an opening in a perforated plate or die shaped to produce the required form, after which the extruded food is cut to size by blades; the machine that forces the mix through the die is called an extruder, and the mix itself is the extrudate, typically driven by a large rotating screw fitted tightly within a stationary barrel ending in the die. The term is sometimes used interchangeably with extrusion cooking, in which the food is cooked with heat as it is forced through the die. Extrusion allows mass production of food through a continuous, efficient process that ensures uniformity in the finished product; foods made by extrusion without simultaneous cooking include pasta, breads such as croutons, breadsticks and flatbreads, pre-made cookie dough and sausages, while foods made by extrusion cooking include many breakfast cereals, ready to eat snacks, confectionery, some baby foods, full-fat soy flour, textured vegetable protein, some beverages, and dry and semi-moist pet foods.