Written by Dr. Ulla Reutner
The plastics industry has appreciated the advantages of extruders since their inception in the 20th century. They enable polymers to be formed into granules and masterbatches, and ultimately into pipes, window profiles and much more. The continuous process is ideal for efficient mass production, scales well and generates very little waste.
Even though the technology appears to be mature in this area, the drive for innovation remains undiminished. The key drivers are sustainability, new materials and digitalisation. To reuse plastic waste, moisture, solvents and contaminants must be removed from post-consumer plastics – using improved degassing systems. Integrated melt filters and multi-stage extrusion make it possible to produce high-quality recyclates from heavily contaminated plastic waste.
For new materials, extrusion is becoming a development platform, for example in the processing of bioplastics, the production of glass-fibre-filled compounds or the incorporation of functional additives. High-performance extruders enable multi-layer extrusion. Micro- and nano-extruders produce extremely small structures, for example for medical technology. Furthermore, extrusion technology is increasingly being linked with new manufacturing technologies, such as 3D printers. Digitalisation supports all of this, for example through the integration of in-line rheology and other sensor technologies in conjunction with AI-supported process control.
The use of extrusion in the food and feed industry is considerably more recent. Yet even there, it has now been firmly established for decades. Originally used primarily to produce simple, starchy products, it is now a highly flexible tool that integrates mechanical, thermal and, in some cases, chemical process steps into a continuous process. Inside an extruder, raw materials are mixed, kneaded, broken down under pressure and temperature, and shaped through a die. This combination makes the technology particularly efficient and versatile – characteristics that make it virtually indispensable for industrial applications.
Classic applications include breakfast cereals, snack products and various pasta products. It enables the expansion and texturisation of starch at high throughput rates. Extrusion also plays an important role in the confectionery sector, as well as in gluten-free or protein-enriched products. In the animal feed industry, its importance is even more pronounced: dry pet food and the majority of modern aquafeeds are produced using extrusion. Solutions for the extrusion of animal feed will be showcased, for example, at the Interzoo trade fair, taking place from 12 to 15 May 2026 in Nuremberg.
The potential for innovation is even greater here than in the plastics industry. This is particularly evident in the field of alternative proteins. The production of plant-based meat analogues is today largely based on so-called high-moisture extrusion. This process makes it possible to create fibrous, anisotropic structures from plant proteins that are reminiscent of muscle meat in terms of texture. Consequently, extrusion has developed into a key technology for the transformation of protein-based foods. As demand for sustainable protein sources continues to grow, further process engineering innovations are required in this area.
Precise control of structure and process is becoming increasingly important. Whilst extrusion used to be carried out primarily on an empirical basis, the focus is now shifting to microstructural considerations. The texture of plant-based products depends heavily on the interaction between raw material composition and process parameters, such as moisture content or protein composition. Even small changes in the geometry of dies or cooling channels significantly influence fibre formation and porosity. Alternative protein sources such as peas, rice or by-products from the food industry, which are now being used alongside the previously dominant soy, are also driving further technical innovations.
A current focus of development is the production of functional foods with specifically tailored nutrient profiles. Analogous to the formation of masterbatches in the plastics industry, additives can be incorporated into food production using extrusion: for example, vitamins, minerals or other bioactive components via premixing or co-extrusion. However, the thermomechanical stress in the extruder can be critical, as heat- and shear-sensitive substances in particular—such as vitamin C, certain polyphenols or probiotic cultures—can be partially degraded. Accordingly, process design requires careful coordination of the temperature profile, residence time and specific energy input. In practice, gentle screw configurations, reduced process temperatures or downstream application steps are used, amongst other things, to minimise active ingredient losses and ensure the desired functionality in the product.
A key lever lies in energy optimisation, particularly in energy-intensive high-moisture processes. Current developments focus on improved screw geometries, optimised heat transfer and reduced process temperatures. In addition, process parameters are increasingly being optimised on a data-driven basis to precisely control energy input and residence time.
As in the plastics industry, the digitalisation of process control is also gaining importance in food and feed processing. In-line sensor technology, model-based control and, in the future, AI-supported optimisation enable significantly more precise control of product quality. As a result, extrusion is increasingly evolving from an experience-driven process towards a data-driven and more model-based process.
In both the plastics industry and the food and feed industry, the significance of extrusion extends far beyond its traditional role in shaping materials. It is not only an efficient production technology for established products, but also a central platform for innovation. In the plastics industry, it offers new solutions, particularly in material recycling. And in the context of sustainable nutrition, its importance in the food industry is likely to increase significantly in the coming years. Furthermore, truly forward-looking sustainability sectors are also utilising extrusion processes, such as battery manufacturing. There, for example, electrodes for various battery types are extruded – using a water-based process, making it particularly sustainable. Another growing trend is the use of hot-melt extrusion in the pharmaceutical industry, which can increase the bioavailability of certain active ingredients.
