Extruding is a process by which a mixture of ingredients is forced through a pierced plate or die. After passing through the plate, the mixture can be cut to a specified size by blades (think Cheerios!) The machine which forces the mixture through the die is called an extruder, and the mix is known as the extrudate. The extruder consists of a large, rotating screw tightly fitting within a stationary barrel, at the end of which is the die plate.Food products manufactured by extrusion usually have a high starch content such as pasta, breakfast cereals and ready-to-eat snack foods. Other food products often produced by extrusion include some breads (croutons, bread sticks, and flat breads), pre-made cookie dough, and some french fries.
Sausages, hotdogs and chicken nuggets are also food items that are manufactured by extruding. These items are often pre-cooked during the extrusion process using steam to heat the extruding equipment. Extrusion is also used to make confectionery products like chewing gum, licorice, and toffee. Home cooks use the process of extrusion when they use a garlic press, potato ricer or a pastry bag to frost a cake.
