Extrusion Cooking for Fortified Blended Foods (FBFs)

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.

Dry extrusion is preferred for the production of Super Cereals. This type of extrusion does not require an external source of heat or steam. All the cooking is accomplished by friction capitalizing on the inherent moisture and/or oil for providing lubrication. The dry extruder can process material bearing 8-22% moisture without the need for drying the extrudate.

Wet extrusion is considered more appropriate for the manufacturing of Super Cereals plus.

The advantages of extrusion are summarised in the scheme next.

Other processing techniques which can apply for the thermal treatment of the raw materials are:

The validation of these techniques is necessary to the extent of ensuring that WFP requirements for product stability, product self-life, energy density and acceptability are met.