Selecting an extrusion design that is not suited for your application is a costly mistake. It can result in a range of problems including but not limited to high scrap rates, undesirable throughput, high equipment costs, excessive energy consumption, and long post-extrusion drying or cooking times. It is necessary to possess a basic understanding of extruder operation and design.
In this blog, we’ll present a small guide to choosing the right food extrusion machinery.
How Extrusion Works
The primary concept of extrusion revolves around transforming ground food products into different shapes. There are numerous situations where this is necessary like manufacturing dog food. Here, multiple ingredients like beef, potatoes, carrots, corn, chicken, and other ingredients are combined into small, bite-sized pellets. The only way to achieve this is via the process of extrusion.
Different Types of Extrusion Methods
Modern food extruders offer an incredible amount of functionality and variability. These machines are widely used within the food industry due to their ability to create a continuous, rapid process to make several food products in a relatively short amount of time. It is a system consisting of several unit operations like mixing, cooking, forming, cutting, and kneading, all contained within a single piece of equipment.
The process starts by receiving and characterizing raw ingredients that are vital for maintaining product consistency. These raw ingredients undergo preconditioning and/or mixing using equipment such as preconditioners and ribbon blenders to maintain uniformity as they are inserted into the extruder. Though it must be stated that both preconditioning and mixing are not mandatory for certain products.
The main extrusion process is the cooking stage where the raw ingredients are converted into formed and cooked products. The post-extrusion process involves cutting the extruded food products into the appropriate size, drying the product to achieve the desired moisture levels, coating or seasoning for a specific flavor, and tasting the product for quality before it’s finally sent on for packaging.
Aside from the major processes, there may exist a couple of additional steps depending on the type of product being manufacturer and its intended use. The extrusion process involves applying high temperature, shear, and pressure on the food ingredients for a small period of time. The process serves to convert solid food ingredients into a melted state, which is then forced via the die positioned at the end of the extruder.
Once the melt exits the extruder, it experiences a sharp drop in pressure which causes it to cool down, expand rapidly, and transform into the cooked product. The final texture and quality of the food product depends on numerous factors including extrusion processing conditions, the properties of the ingredient mixture, and post-processing conditions.
Owing to the flexibility offered by food extruders, it is used for a range of applications within the food industry. Common examples include:
- Chewing gum, licorice, and caramel
- Animal feeds
- Oilseed meals
- Pasta products
- Precooked soy flours
- Potato and corn snacks
- Precooked starches
- Transforming casein into caseinate
- Flavor encapsulation
- Chocolate conching
- Gelatin gel confectionaries
- Snacks with internal fillings
- Instant rice puddings and pre-cooked flours
Now, let’s move on to selecting the right food extrusion equipment.
Selecting the Right Equipment
When it comes to selecting equipment best suited to your operations, it’s imperative to establish your space constraints, throughput requirements, product profile specifications, and input power requirements. The extruder manufacturer generally requests a sample needed for laboratory testing using your product material. This information is vital when determining the right feed requirements, die and screw design, and equipment size.
After the extruder size is determined, the drive options must be considered. A compact design ensures more flexibility when fitting new lines or designing a new facility. Multiple drive options also add to the flexibility. Utilizing a gear motor requires less maintenance and ensures compact designs. Factors like space constraints often dictate drive designs.
Ancillary equipment is crucial for bringing out desired characteristics within the end product. In certain pelletizing applications, extruding onto conveyor belts proves sufficient; however, in other cases, it may prove necessary to add an oscillating or vibrating conveyor.
Finally, pelletizing requires a die face cutter. Profile applications, on the other hand, demand downstream cutting and wrapping in certain cases. Multiple hold plates are common features in pelletizing whereas a forming die may range from a basic cylindrical shape to more complex designs like ones used for pretzels, topping bits, and certain types of pasta.
In conclusion, working with experienced manufacturers opens the door to consultation services that can help you determine the best course of action. CFAM is an established food extrusion equipment manufacturer that fits the description and can help you determine the best type of food extrusion equipment!
Get in touch with us today for more information.