High protein concentrations even in the dry process
4/2/2024 Insights Interview

High protein concentrations even in the dry process

Plant-based proteins are becoming increasingly important for nutrition. However, the process engineering and energy requirements for their production are high. In an interview with Industry Insight, Markus Eggenmüller explains what is important and what the machine manufacturer Hosokawa Alpine is working on to optimise the process.

Markus Eggenmüller, Head of Sales Food Division at Hosokawa Alpine Markus Eggenmüller, Head of Sales Food Division at Hosokawa Alpine

What technical challenges do you see in the production of plant-based proteins?

Producing plant-based proteins from raw materials such as wheat, soya, peas, lentils or other pulses is simple in principle. However, demand is increasing and with it the need to scale up the technology – industrial plants are already processing several tonnes per hour in some cases. In addition, the quality requirements are becoming more stringent, because ultimately the aim is to achieve the right flavour and the required texture. To achieve this, the processes must be optimised and adapted to the requirements of the food industry.

What are the special process engineering features of the production of plant proteins?

With the new foods and especially with protein shifting, we mainly work with dehulled goods. These are finely ground in classifier mills, for example. The aim of deagglomeration is to separate the proteins from the starch granules. The product is left in the grinding chamber for a long time so that the cell structure can be broken down finely enough. The protein-rich fraction is then separated from the starch-rich fraction at approx. 16 to 20 µm in a multiple separator. The protein concentrate is then processed in an extruder into patties, for example, or further processed. Alternatively, protein isolates are produced in a wet process.

That sounds like classic mechanical process engineering. What are the special features of protein production?

It's true, it's essentially a classic technology that has only been improved in nuances. For example, the separators are optimised to achieve better selectivity. But compared to the traditional production of animal feed from pulses, completely new qualities and varieties are being defined for human nutrition. There are specific specifications as to how high the protein values should be. And this is where it gets technically exciting: depending on the variety used, up to 70 % protein content can be achieved in dry processes - that is close to isolate. So if we succeed in eliminating the wet process through a suitable combination of specially cultivated raw materials and mechanical process technology and the products also achieve the required properties, then we can save a lot of effort and energy.

What role does sensor technology play in this?

A very important one. We need to gain a better understanding of the relationships between the raw materials used and the end product that can be achieved with the help of technology. And this is only possible with appropriate sensors. Until now, samples have often been taken and analysed in the laboratory - which of course takes far too long for process control and largely forces manufacturers to fly blind. Online sensor technology, e.g. using near infrared, promises a remedy here - however, the boundary conditions are challenging: the pipelines have enormous diameters and fine grinding naturally produces flammable and explosive dusts, which is why explosion protection must also be taken into account. But if we understand the processes with the help of sensor technology, we can ultimately control them in a targeted manner.

We also work together with breeders and farmers so that they can grow what is needed for the new protein products. Those who bring together this expertise from all interfaces create real added value for their customers.

Powdered plant protein produced by dry fractionation Powdered plant protein produced by dry fractionation

High-protein flours through dry fractionation

Hosokawa Alpine offers two processes for the production of high-protein and high-starch speciality flours: the precision process and the standard process. In dry fractionation, the smaller protein particles and the larger starch particles are deagglomerated and the finer protein particles are then separated from the coarser starch particles.

The Zirkoplex ZPS classifier mill is used in the precision process, while the finely ground product is fractionated using the Turboplex ATP classifier. This results in two products: a fine protein concentrate and a coarse starch concentrate.

Production plant for plant proteins at Müllers Mühle Production plant for plant proteins at Müllers Mühle
Hosokawa Alpine's standard process for dry fractionation involves efficient fine grinding with the Contraplex CW II pin mill and high-performance sifting of the finely ground product with the ATP air classifier. For some products with a high fibre and/or oil content, the Contraplex CW II mill is recommended to efficiently deagglomerate these components. In addition to the extraction of proteins from cereals or pulses, other valuable protein sources such as sunflower extraction meal, pseudocereals, guar gum, locust bean grits and food by-products from brewing and oil extraction processes can also be processed. This enables not only the extraction of valuable proteins, but also the fractionation of other valuable ingredients such as dietary fibre.


Armin Scheuermann

Armin Scheuermann

Chemical engineer and freelance specialised journalist