Extruders in Food Production

Single-screw extruders
The compression screw of a single-screw cooking extruder has a reduced channel depth that increases shear and mechanical energy input for heating when rotating at high speeds. The resulting friction causes the product to heat up. In some cases, the barrel is equipped with a steam jacket for additional contact heating in the metering section. To increase output and efficiency, steam is usually added in a preconditioner for preheating before the raw materials enter the extruder. Types of single screw extruders include:
Cold forming (pasta type) extruders: Deep grooves, smooth barrels, low shear rates. Little or no cooking required. Used to make pasta, pastry dough, cookies, egg rolls, ravioli, processed meats, and some confectionery.

Chuck extruders: High shear extruders with grooved barrels and multiple shallow grooves in the screw. Used to make puffed snacks and puffed wraps or chucks.
High shear cooking extruders: High shear extruders with variable groove depth screws, HTST equipment. Used to make pet food, ready-to-eat cereals (RTE), confectionery, crispbreads, precooked food ingredients, pregelatinized cornmeal, dry food mixes, instant beverage powders, croutons and bread crumbs, cookies and crackers, enzyme deactivators for whole fat soy flour, imitation nuts, famine relief feeds, textured vegetable protein (TVP), and enzyme deactivators in grains and oilseeds.