1. What is extrusion?
2. What are the advantages of food extrusion?
3. Why must manufacturers consider twin screw technology?
4. How do twin-screw extruders differ from single screw extruders?
5. What are the advantages of twin screw extruders over traditional processing methods?
6. Why invest in CFAM’s extruders?
7. What products are made on twin screw extruders?
8. What are the components of a typical twin-screw extruder?
9. How does a twin screw extruder operate?
10. What is the difference between an expanded product and a formed product?
11. What does an extruder cost?
12. Can I trust CFAM with my product or business concept?
1. What is extrusion?
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.
2. What are the advantages of food 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.
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3. Why must manufacturers consider twin screw technology?
Twin screw food extrusion cooking is the future. Today, extruders can be used for producing both human and animal foods, as well as industrial products. Manufacturers are discovering the many benefits of extrusion cooking over traditional methods, e.g. increased productivity, energy savings, reduced production costs, a minimal impact on the environment, clean process effluents.
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4. How do twin-screw extruders differ from single screw extruders?
The twin-screw extruder (TSE) was developed to overcome the limitations of the single screw extruder. With the TSE you have the following advantages:
• Twin-screw extruders (TSE) are 1.5 to 2.5 times more expensive to acquire.
• TSE’s offers greater flexibility – it can handle a much wider variety of materials.
• TSE’s have a uniform shear rate across the channel depth, a narrower residence time distribution, and better mixing and heat exchange capabilities.
• TSE’s are easy to operate, control and are more flexible and less complex.
• TSE’s are “self-cleaning”.
• Reduced start-up and shut-down costs, which will save time and money especially on high volume production lines.
• It is possible to achieve better product quality with a TSE.
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5. What are the advantages of twin screw extruders over traditional processing methods?
Compared to traditional cooking methods, the advantages are:
• New products: TSE’s give you flexibility and process control which is not always possible with traditional methods.
• High productivity: The TSE acts as a complete processing plant. Extruders can produce over 16 tons per hour of finished product.
• High product quality: It gives you an almost unlimited control over the cooking process and changes can be made quickly during the cooking process.
• Low cost: TSEs are cost-effective to operate because they perform the functions of mixing, blending, cooking and forming.
• Versatility: A wide variety of food can be produced on a TSE, by varying the ingredients and processing conditions.
• Energy efficiency: In some processes, TSE can actually reduce energy needs. Products can be cooked more quickly and efficiently because of more precise temperature and moisture control, and shorter reaction times.
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6. Why invest in CFAM’s extruders?
The following features make CFAM extruders ideally suited for the African continent:
• It has been designed and manufactured in Africa for Africa.
• It is competitively priced.
• The extruders have been designed to be modular – a number of different products can be made on the same extruder.
• The extruders are built and commissioned at the CFAM premises and tested thoroughly. The extruder is dispatched to the client’s site where it can be installed and commissioned within a day.
• To ease the maintenance burden and cost most of the components can be purchased from local outlet shops.
• CFAM can perform maintenance work on the extruders and consequently, plants will not be affected by breakdowns for long periods of time.
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7. What products are made on twin screw extruders?
Extrusion can be used in for example the manufacture of snack products, breakfast cereals, heath bars, crisp breads, ice cream, confectionery and animal food. Plastic and wood composites can also be manufactured.
The following is a comprehensive list of products:
• Pet foods
• Corn-Soy-Blends with cereals and legumes for the N 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, like “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.
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8. What are the components of a typical twin-screw extruder?
The main components are:
• The screws;
• The barrel;
• The drive motor with speed control;
• The gearing mechanism;
• The die; and
• The product cutter.
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9. How does a twin screw extruder operate?
There are three areas: the Feed Area, the Cooking Area and the Forming Area.
In the Feed Area, raw ingredients are continuously fed from storage into the extruder. The twin screws intermesh as they turn, mixing the ingredients. Liquid, usually shortening, water or others, is injected through ports in the barrel to hydrate the grains before cooking. The ingredients are worked into a continuous dough by the screw action.
In the Cooking Area, the dough is subjected to heat from one or all sources of heat i.e. mechanical heat, convective heat or steam heat.
In the Forming Area, the product is given a shape. Depending on the moisture level, temperature, pressure and the geometry, an expanded or formed product can be obtained.
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10. What is the difference between an expanded product and a formed product?
Expanded products
To manufacture expanded products, the pressure and temperature are increased, while the moisture level is accurately controlled. When the product exerts the extruder through the forming die, the change in atmospheric pressure causes the internal moisture to turn to steam. This puffs he fully-cooked dough into an expanded product.
Formed product
To create formed or pelletized products, a high moisture dough is used at a lower temperature. When the extrudate is forced through the forming die, the product takes the shape of the die, instead of expanding. The result is a dense intricately-shaped pellet.
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11. What does an extruder cost?
Please contact us for a quotation.
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12. Can I trust CFAM with my product or business concept?
Yes. If required, a confidentiality agreement can be signed by all parties to ensure the confidentiality of a product or business concept.