What is extrusion?
Extrusion is one of the most energy efficient cooking processes, it is environmentally friendly with no waste streams. It is also ideally suited for processing of agricultural waste and by-products. Generally, extrusion is defined as a process of forcing material through a defined opening. For this to happen, the material must be either completely or partly in a fluid form so that it doesn't block the opening when operating under reasonable pressure conditions.
Examples of extruded foods include pastas, breakfast cereals, cookie dough, potato chips, baby food, dry pet food and ready-to-eat snacks. Examples of fibre polymer products are window and door frames, fibre polymer wood analogue panels, deck panels etc.
Examples of extruded foods include pastas, breakfast cereals, cookie dough, potato chips, baby food, dry pet food and ready-to-eat snacks. Examples of fibre polymer products are window and door frames, fibre polymer wood analogue panels, deck panels etc.
What are the advantages of extrusion?
Extrusion is one of the most energy efficient and environmentally-friendly processes to produce pre-cooked ready-to-eat products. Extrusion has wide applications in the food, feed, powder paint and plastics industries. There are numerous opportunities in the market for the development and marketing of extruded products. The potential of using extrusion to add value to products is largely untapped in Africa.
Benefits of extrusion
- Continuous high throughput processing of foodstuffs.
- Processing of relatively dry, viscous materials.
- Improved textural and flavour characteristics of foods.
- Control over the thermal changes of food constituents.
- Use of unconventional ingredients.
- Reduced effluents.
- Enormous energy saving as a result of highly energy efficient processes
Products made by twin-screw extruders
Extrusion can be used in the manufacture of snack products, breakfast cereals, health bars, crisp breads, ice cream, confectionery and animal food. Plastic and wood composites can also be manufactured. Here is a comprehensive list of products:
- Pet foods
- Corn-Soy-Blends with cereals and legumes for the UN or World Food Programme.
- Infant food.
- Extruded oilseeds into crude oil and partially defatted cakes/granules/flour.
- Bioreactor or bio-extrude with enzymes to obtain high density grain products.
- Extruded, floating or suspended pellets for fish.
- Wood/plastic composite products/structures.
- Extruded composite cereals from e.g. wheat, sorghum, cassava, barley, rice, peanuts, millets, peas, beans, sweet potatoes, green bananas, plantain.
- Third generation (3G) extrudates or high density, expandable, snack pellets to be puffed in hot oil or a microwave oven, e.g. “nik naks”.
- Texturised Vegetable Protein (TVP®) for instance soy-mince.
- Extruded pasta noodles from composite cereal flours.
- Protein-enriched snacks and breakfast cereal flakes (extruded/rolled, toasted).
- Extruded cereal-substrates for ethanol fermentation and extruded ethanol-by-products.
- Intermediate-extruded, meat analogues.
- High-moisture extrusion cooking (HMEC) or restructured/processed, whole-muscle meat alternatives or textured, vegetarian soy-based meat analogues.
- Starch-based, low-density, direct-expanded foams as packing material/fillers.
- Bio-degradable (edible) extruded starch plus polymers as packaging films.
- Extrusion cooking of breading to coat nuggets of chicken, fish, cutlets etc.
- Co-extrusion of multi-layered, multi component snacks simultaneously.