Published: 09.09.2022

Reading time ca. 6 Min.

Success Story Clextral

Extrusion of meat substitute products

Meat substitute products could be part of the solution to feeding a rapidly growing world population. Kubota Brabender Technologie has successfully partnered with Clextral, a French manufacturer of extrusion plant and equipment, in this market for many years.

One of the greatest challenges of the 21st century will be to feed the growing world population, while taking environmental protection and animal welfare into consideration. Global meat consumption has more than doubled in the last 50 years. The consequence of this is that the extreme increase in industrial livestock production has had a massive environmental impact. The negative effects of excessive meat consumption on human health have also been proven. And last but not least, this raises ethical questions in relation to animal welfare.

Foto: Some sources of vegetable protein from left to right: chickpeas, peas and soybeans.

Some sources of vegetable protein from left to right: chickpeas, peas and soybeans.

Flexitarians and meat substitutes

These worrying developments have given rise to a new food trend: a conscious reduction in people’s personal meat consumption. Although so-called flexitarians regularly eat meat, they are mindful of quality and the environment, and try to incorporate healthy, plant-based, protein-rich alternatives to traditional meat products - meat substitutes - in their diets. They resemble real meat in terms of flavor, appearance and texture, but consist of plant-based proteins containing highly effective essential amino acids, which are free of cholesterol, low in fat as well as rich in protein, fiber and nutrients. The most important sources of plant-based proteins include wheat gluten, soya beans, peas, lentils, fava beans, chickpeas, runner beans and lupins.

Clextral: the food extrusion expert

Since the late 1990s, French manufacturer of extrusion plant and equipment Clextral has been working together with food processors and food research centers on the development of convenience foods made of fibrated protein products, which consist of extruded fibrous proteins. In the past few years, the sales figures for textured vegetable proteins in Europe, Asia, America and Australia have increased steadily. Since 2001, Clextral has held a patent for High Moisture Extrusion Cooking – one of the two twin-screw extrusion processes used to manufacture meat substitute products from proteins.

The end products of the High Moisture Extrusion Cooking process have the potential to help feed the growing world population on a sustainable basis in the future.
Emmanuel Lavocat, food extrusion process engineer at Clextral

Two extrusion processes: HMEC and TVP

In addition to the High Moisture Extrusion Cooking (HMEC) process, there is also a “dry” process called TVP (Textured Vegetable Protein). The two extrusion processes differ from one another in terms of the configuration of the extruder and the die used. In the dry extrusion process, Clextral usually feeds a premix made of soya powder or pea concentrate with a protein content of between 50 and 60 percent into the extruder. Using a simple die produces an extrudate with a spongy texture and a low moisture content of 10 to 23 percent as it exits the extruder die and of around 8 percent as it exits the dryer following extrusion. That is why it still has to be rehydrated when being processed into finished products in the food processing industry and when being consumed by consumers at home.

High Moisture Extrusion Cooking (HMEC)

Plant-based raw materials like peas or soya are also used in the HMEC process, although in the form of isolate or concentrate with a higher protein content of 70 to 80 percent. The difference compared to the dry process is that HMEC involves thermomechanically processing – “cooking” – the proteins at temperatures in excess of 120 degrees Celsius and at a high moisture content of 50 to 70 percent, as well as relatively long dwell times. This process enables fiber formation and takes place in a complex screw and barrel configuration within the twin-screw extruder, where the specific screw configuration features a high length to diameter ratio.

Emmanuel Lavocat, food extrusion process engineer at Clextral, describes it as follows: “In their original state, proteins are like woolen threads that are interwoven. During the cooking process in the extruder, they are disentangled, unfolded and cut into small pieces. In the die, they are then re-crosslinked to produce even filaments of good quality.”

Cooling die influences texture

A long cooling die is positioned behind the screw-barrel configuration, and it plays a key role in the HMEC process. The setup of its cooling channels, the cross-sectional area and aperture dimensions all have a major impact on the texture and quality of fiber formation. For example, both rough surfaces featuring relatively short, thick, cross-sectionally oriented fibers as well as smoother surfaces with long. thin, laminar-flow-oriented fibers are feasible. Each of these products is used for specific food applications, for example, as analog chicken strips or analog pulled pork. HMEC creates intermediate products, the structure and texture of which closely resembles the muscles found in meat. Further processing also enables flavor, olfactory and visual features to be added.

Look into the future

“The end products of the High Moisture Extrusion Cooking process have the potential to appeal to consumers, who have previously viewed analog meats with skepticism,” says Emmanuel Lavocat with conviction – and they could help to feed the growing world population on a sustainable basis in the future.

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Interview with Clextral

FLUX spoke with Jérôme Mottaz (JM), Head of Engineering and R&D, and Emmanuel Lavocat (EL), food extrusion process engineer, both from Clextral, about the partnership with Kubota Brabender Technologie and about future market trends.

FLUX: Mr. Mottaz, what role does feeding play in the manufacturing process?
JM: Industrial food production always involves absolute precision. That is why accurate feeding is very important for the whole process. All ingredients have to be put into the extruder in precisely measured quantities. The degree of precision applied at the start of the process ultimately influences all the parameters of the end product. You can always rely on Kubota Brabender Technologie’s gravimetric feeders functioning with absolute precision.

FLUX: How do you find the right feeder for each of your customers’ applications?
JM: In our Technical Center in Firminy, we can test the different quantities involved in almost all food applications. Kubota Brabender Technologie has provided us with a large number of different gravimetric feeders to enable us to do this. This enables us to try out the required raw materials and specific formulations on different feeders. At the same time, we can draw on Kubota Brabender Technologie’s expertise and their technical centers around the world at any time.

FLUX: What benefits do Kubota Brabender Technologie’s feeding systems provide?
EL: Food safety plays an overriding role in food manufacturing. The special Hygienic Design concept incorporated in Kubota Brabender Technologie’s feeders reliably meets that requirement. What we particularly value is that Hygienic Design can be flexibly adapted to meet the specific requirements of the customer – from minimum requirements to a very high standard, High Hygienic Design. Furthermore, it also highlights two other very important aspects: the feeders have an excellent standard of cleanability and are easy to operate.

FLUX: In which direction might the market for meat substitute products be headed in the future?
EL: Raw material diversity will increase. We are already testing many new raw materials, such as chickpeas, fava beans or lentils, which are equally suitable for wet extrusion. However, given their limited availability on the world market, they are still too expensive. But this may change in the future, as many consumers reject genetically modified products like soya, because of ethical and health concerns.

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FLUX: What does that mean in technology development terms?

JM: A major challenge is enhancing performance while keeping the same level of spec. Our R&D team is already addressing this issue. Product expertise and process know-how are the key issues in creating the best analog meats from various sources of protein.

FLUX: Mr. Mottaz, Mr. Lavocat, many thanks for the interesting conversation!

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