Forming, moulding, extruding
Forming/moulding and extruding are operations to achieve a certain shape of solid materials.
Field of application
Forming/moulding is an operation widely applied in the production of chocolate, bread, biscuits, confectionery and pies. Moulding is also an important process step in cheesemaking.
Extrusion is widely used in the production of meat sausages, confectionery products and starchbased snack foods.
Description of techniques, methods and equipment
a) Forming/moulding
The material to be moulded is in a viscous form and is fed into the appropriate mould. As the moulding process progresses the material becomes firmer and solidifies, up to the point that it becomes a fixed shape.
b) Extrusion
Extrusion can be seen as a continuous process of shaping. The material is kneaded under high pressure and pressed continuously through openings of the required shape. In cooking extruders, the material is also heat-treated (cooked), to solubilise starches. Extruders can contain one or two screws. The rotation of the screws transports and mixes the material and produces pressure build-up.
