What kind of Extruder?
An Extruder is not just an Extruder, and most importantly, “any” extruder is not capable of doing “any” kind of extrusion job. Extruders are designed to do specific jobs effectively and efficiently. Some are more flexible than others, but still, there is no single design capable of covering the entire range of Extrusion Applications we are facing today.
Looking at the list of potential Food and Feed products we discussed before again, and it is easy to understand that a wide range of different ingredients will be required to manufacture these individual products.
These ingredients all have different Physical and Food-chemical characteristics. For example, some are high in Fat content and low in Protein, while others have low levels of Fat and high levels of Protein, and so forth. This varying-ingredient-characteristic situation requires Extrusion Operating Conditions controlled to specific levels in order to successfully add value to the ingredients or formulations we are processing.
It is therefore of utmost importance to carefully consider the following before making a decision to invest in an extruder:
- What are the ingredients or formulations to be extruded?
- What are the End Products (and their desired characteristics) we wish to produce by means of Extrusion?
- Are there any Anti-Nutritional Factors to be dealt with?
- Are there any physical characteristics we need to provide to the final product? Examples may include
- Buoyancy in the case of Floating, Slow-Sinking or Sinking Aquatic Feeds
- Texture in the case of TVP (Textured Vegetable Protein) and TSP (Textured Soy Protein)
- Shape and Size in the case of Aquatic Feeds, Petfoods, some Animal Feeds, Snack Foods or RTE Breakfast Cereals.
- “Mouth Feel” in the case of RTE Breakfast Cereals and Snack Foods
hp dezign can assist with Business Modelling and Feasibility Studies helping customers to make sure they make the correct Extrusion Decision.
The following discussion briefly describes typical applications. Please contact hp dezign should you need to discuss your specific aspirations in more detail.
High Shear Extrusion
Over the years High Shear Extruders had been referred to as “Low Cost Extruders” or “Dry Extruders”. We believe “High Shear Extrusion” describes it best.
In general, High Shear Extrusion is the preferred technology for processing ingredients and formulations that are high in Oil Content; high in Moisture Content and where high Shear Rates are required for functional purposes. Typical applications for High Shear Extruders include :
- Oilseed processing – examples are FFS (Full Fat Soybean Meal); Partially Defatted Soybean Meal as well as Partially Defatted Soy Flour (when using Mechanical Oil Presses in conjunction with High Shear Extruders)
- By-Product Processing – There is great potential co-extruding by-products from both animal (for example from meat & fish processing plants) and plant (from vegetable, fruit, cereal processing facilities) origin with other ingredients of physical and nutritional value. The end result is turning cash outflow (when dealing with by-products from processing plants) to cash inflow where we produce by-product meals of value in animal nutrition or products of value to Industry. Examples may include
- Bio-degradable packaging
- Aggregates for functional floor designs in animal husbandry systems
- Organic Fertilisers, etc
- Textured Vegetable Proteins (TVP’s) – these may be produced from a range of ingredients high in natural protein content. TVP includes TSP (Textured Soy Protein) made from Soybeans. High Shear Single Screw Extruders are ideally suited to making Meat Extenders that could be used in both food and petfood applications.
- Raw Material Enhancement – for example starch gelatinisation or dextrinisation.
- Shaped Animal Feeds – High Shear Extruders can make some Shaped Feeds, but have limitations