Extrusion is the process of forcing a material through a specifically designed opening. Material is continuously metered into an inlet hopper and then transported forward by the rotating screw. as the material approaches the die, there usually is an increase in pressure and temperature.
Mechanical disruption of the cell walls and starch of plant products occurs during extrusion cooking, facilitating digestion, and absorption. This mechanical breakdown of starches reduces the viscosity of gruels made from extruded cereals to enhance their caloric and nutrient density. The high-temperature heat treatment effectively pasteurizes the product. A good packaging is required to provide resistance to moisture and insects.
Extrusion cooking is the recommended method for manufacturing Fortified Blended Foods.