Extrusion expanded cereal

Extrusion is a process in which foods are rapidly cooked under heat and pressure generated as the product progresses through an extruder barrel.

It is typically used in grain and soy-based products with applications in pet foods, expanded breakfast cereals, expanded or puffed snacks, textured vegetables proteins, meat analogs and pasta.

Extrusion cookers are used extensively in the ready-to-eat (RTE) cereal industry to cook doughs that are cold formed into various shapes and then gun or tower puffed. These products are what is called indirect expanded RTE breakfast cereal. In some instances, these types of cereals are referred to as half products because the cereal is only halfway through the extrusion process.

Cereals that have high amounts of lipids are more difficult to expand due to dough slippage within the extruder barrel. This type of cereal usually requires high moisture and high temperature before significant puffing will occur.

 Snack foods and cereals that expanded on exiting the extruder are called direct expansion. These are typically made from cereals grains such as corn, wheat, rice, and oats. Direct expanded snack products are typically produced in a high-shear cooking extruder at temperature greater than 100°C. In the extruder, pressure is high enough to keep the water in liquid form.

Ingredients for snack products are mixed and blended prior to being fed into the extruder. For some products the cereal grain is premoistened prior to being introduced by some feeding device into the extruder. The cooking process in extrusion generally enhances digestibility of the starches and proteins and can be effective in removing anti-nutrients.
Extrusion expanded cereal