Method for producing a texturate and extruder assembly

Abstract

The invention relates to a method for producing a texturate, in which a protein mixture is provided, comprising at least one first protein mixture, in particular a pea protein mixture or a broad bean protein mixture, with a weight proportion of between 45 wt.% and 75 wt.% relative to a base mixture. Water is added in a weight proportion of between 25 wt.% and 50 wt.% in relation to the basic mixture to form a dough and the dough is then extruded at a maximum temperature of between 110°C and 160°C to form an extrudate. The extrudate undergoes an elongation deformation at a temperature of greater than 100 °C by feeding the extrudate through an elongation nozzle, wherein the geometry thereof changes over its length such that a longitudinal and / or transverse elongation strain is generated on the mass.

Description

[0001] Method for producing a texture and extruder arrangement

[0002] This application claims priority from German patent application DE 102023106026 . 0 of 10 March 2023, the disclosure of which is hereby incorporated in its entirety by reference.

[0003] The present invention relates to a method for producing a textured product and an extruder arrangement.

[0004] BACKGROUND

[0005] Plant proteins in the form of isolates or concentrates are now used in a variety of meat substitutes. This is due, on the one hand, to increased demand for vegetarian or vegan diets and, on the other, to consumer desire for sustainable and resource-efficient agriculture.

[0006] Vegan food products made from plant proteins have the advantage, among other things, that they can be produced from domestically or locally produced raw materials. Pulses in particular, but also other plant-based substances, have the advantage over soy or other substances that they can be cultivated in a more resource-efficient manner. This is countered by a growing demand for various plant-based food products.

[0007] Traditionally, products based on vegetable proteins are manufactured by dry or wet extrusion. Dry extrusion is carried out at high temperatures T > 130 °C and a moisture content < 30 %. A short, narrow die without cooling is used for extrusion. This enables the production of directly expanded products, so-called TVP (textured vegetable proteins). In dry form, they are rather irregular, porous and glassy and, after being rehydrated, are further processed into the final products. The final product has a sponge-like structure with no appreciable anisotropy and either no or only very short fibers. They bear little resemblance to the sensory properties of meat analogues and are often used in blended products (e.g. burger patties, etc.) rather than for whole products.

[0008] Moisture extrusion (HME) is the current technology used by industry to produce fibrous, plant-based protein products. The resulting products often provide a satisfactory base, exhibiting an anisotropic, meat-like structure, texture, and appearance.

[0009] In such a wet extrusion, the mass is kneaded and pressed through an elongated cooling slot die or an extended cooling couette die. In both cases, the protein-based matrix is ​​extruded at relatively high temperatures (T > 130 °C) and high water contents (>50%) in the screw section of the extruder and then forced to flow through a subsequent cooling die, where the material is continuously cooled (typically to below <100 °C at the die outlet) to prevent expansion, which could destroy the fibrous structures produced in the die section.

[0010] Although this method can be applied to a variety of plant-based raw materials to produce fibrous protein-based products that acceptably resemble meat products in appearance and, to some extent, in taste, they lack either long fiber structures or the desired tenderness, both of which are necessary to successfully replicate the properties of cooked meat.

[0011] It has been shown that the resulting products have fiber-like structures of only short length, whereas real meat consists of longitudinal fibers up to 30 cm long. Depending on the implementation, the fiber length of the plant proteins can be increased somewhat, but the resulting end product is very compact, hard, and exhibits very strong elasticity, which does not lead to the desired mouthfeel of the meat products. There is a need to make further changes to conventional technologies at this point in order to achieve product improvements.

[0012] SUMMARY OF THE INVENTION

[0013] This need is met by the subject matter of the independent patent claims. Further developments and embodiments of the proposed principle are specified in the subclaims.

[0014] Previous research assumed that fiber formation in the molded part and the exit nozzle results from multiphase gel formation at high temperatures and the subsequent deformation of this multiphase system by shear stresses in the molded part , with the mass being cooled to less than 100 ° C in order not to destroy the fibers .

[0015] Although this method has proven successful for producing fibrous protein-based products, typically similar to meat products, controlling the resulting fiber formation remains a challenge. This requires precise control of gel formation, cooling, and shear forces in the molded part, which in turn vary greatly, since such highly elastic materials exhibit wall slip and melt fracture phenomena that significantly affect the deformation history. Wall slip or melt fracture lead to a sudden pressure drop in the die and thus to expansion of the mass, and besides fiber disruption, to unstable behavior.

[0016] As a result, many meat products, especially those with long fiber structures, cannot be adequately imitated using this technology. It can produce fibrous structures that have a parabolic shape (due to shear flow) and a relatively short length, whereas real meat consists of longitudinal fibers up to 30 cm long.

[0017] Furthermore, available die technologies can only be used to texture protein-based matrices with very specific properties. Typically, suitable protein sources should exhibit very high gel strength and viscosity after treatment in the screw section of the extruder, as this significantly influences the shear stresses in the die section (low viscosity, low deformation stresses, no fiber formation). This limits the use of many protein resources that could be cheaper, more sustainable, or healthier.

[0018] Definition of protein mixture

[0019] For the purposes of this application, the term "protein mixture" means a plant protein mixture. Such a plant protein mixture is usually obtained from a single plant species in the manufacturing process, although impurities from other plants may occur to a small extent.

[0020] Unless otherwise stated, a "plant protein" comprises a plant protein mixture from the respective plant; otherwise it is referred to as a "single plant protein". In addition to the actual plant proteins, the mixture can also contain other components such as starch, sugar, fiber, minerals, fats and oils. Likewise, individual amino acids can be part of the protein mixture. The respective amounts are defined in more detail below in the terms concentrate and isolate.

[0021] Similarly, a "pea protein" or a pea-based plant protein is a protein mixture which essentially comprises pea, pea components or proteins of the pea plant and which has been processed accordingly.

[0022] A protein mixture can be obtained from the plant species itself, but can also be the result of a side stream. There are also various side streams, press cakes, and residues that can be used as a protein source and thus represent protein mixtures within the meaning of this definition. These include, but are not limited to, residues from sugar production, the production of alcoholic beverages such as beer and wine, residues and side streams from oil production such as soybean oil, coconut oil, and rapeseed oil, or plant-based milk production such as oat milk, pea milk, or field bean milk.Further examples of various side streams from which protein mixtures can be produced or which contain these include okara (soy pulp), almond pulp, oat pulp, coconut pulp / meat, sunflower cake, rapeseed cake, linseed meal, hemp cake, cashew residues and peanut cake and corn gluten meal, whey protein, casein micelles, potato fruit water, chickpea pulp, lentil residues, spent brewer's yeast and spent malt (beer leavener).

[0023] Other plant proteins that can be processed as concentrate, as isolate (see the definitions there) but also in other forms as protein mixtures include, but are not limited to, textured soy protein, tempeh, hydrolyzed wheat protein, mycoprotein (fungal mycelium, for example from Fusarium venenatum), rice protein, potato protein, corn protein (zein protein), hemp protein, algae protein, e.g. from spirulina or chlorella, rapeseed protein, sunflower protein, cottonseed protein, pumpkin seed protein, quinoa protein, amaranth protein, millet protein, spelt protein, oat protein, barley protein, lemna protein, cassava protein, coconut protein, macadamia protein, cashew protein, chia protein, linseed protein, sacha inchi protein, watermelon seed protein, pistachio protein and yeast protein.

[0024] These proteins can in turn be divided into pulse proteins and non-pulse proteins. Depending on the desired texture, pulse protein mixtures can be combined with non-pulse protein mixtures and processed using the method presented.

[0025] Definition of legume protein

[0026] A legume protein is a protein mixture obtained from legumes. These include peas and broad beans, as well as lentils, mung beans, chickpeas, white beans, and peanuts. Soy also belongs to these, but unless explicitly stated, it should also be considered a legume protein, even though the cultivation of soybeans consumes significantly more resources than other legumes.

[0027] Definition of non-legume protein

[0028] A non-pulse protein is a protein mixture that includes plant proteins that do not originate from a pulse. They are therefore obtained from other crops that are not listed as pulses in the above definition and do not constitute such. In addition to wheat, this includes all other cereals and grains, such as oats, as well as hemp, potatoes, rice, hemp, pumpkin seeds, corn, as well as rapeseed and sunflower. Proteins from algae, yeast, fungal mycelium and / or fungal fruiting bodies also fall under the category of non-pulse proteins.

[0029] In this context, protein mixtures from these plants are also referred to as other protein mixtures and are thus distinguished from protein mixtures from or with legumes.

[0030] Definition of concentrate and isolate

[0031] The terms plant protein isolate and plant protein concentrate each describe plant protein mixtures that differ in the concentration of their protein content. The other components of an isolate or concentrate include fats, sugars including starch and cellulose, which remain in the mixture when the concentrate or isolate is processed. The individual other components are reduced compared to the original concentration, but residues are still present in the isolate or concentrate in varying concentrations due to the various processing options. There is also a small amount of residual moisture in the isolate or concentrate.

[0032] A plant protein isolate, for example, is a mixture of a plant protein in which the concentration of the protein in the mixture is in the range above 85% by weight, for example in the range from 87% to 97% by weight. In a plant protein concentrate, the weight proportion of the plant protein is usually in the range below 80% by weight or even below 70% by weight, for example in the range from 40% by weight to 75% by weight! or even up to approx. 80% by weight. There is also a transition area which, depending on the protein mixture, ranges from 75% by weight to 85% by weight and in which, depending on the manufacturer, protein variant or other parameters, the term concentrate or isolate is used.

[0033] Depending on the processing and manufacturing process, a plant protein concentrate or plant protein isolate can be obtained from a plant species. Thus, the manufacturing process significantly influences not only the concentration of the plant protein mixture, but also, if necessary, the composition of the remaining components and the residual moisture content.

[0034] Definition of other ingredients

[0035] In some aspects, additional functionality in protein composition, taste, textural composition, visual or tactile properties can be achieved by at least one additional ingredient. It should be noted here, firstly, that the above-mentioned protein mixtures from the various fruits are mixed, both in terms of the different fruits and in terms of concentration. An example would be mixtures of pea protein and broad bean protein, but possibly also additions of wheat or rice protein to a protein mixture from soy or pea.

[0036] Other ingredients such as salt, spices, additional starch, sugar, syrup, fats or oils may also be present. These can be added as part of the raw mixture at the beginning, or alternatively or additionally during processing. It has surprisingly been found that sugar, oils and salts and / or in the form of ingredients containing sugar, salt or oil, e.g. grape juice concentrate or soy sauce, can not only adjust the taste but also change the texture. These additional ingredients can be present in free form, but can also be bound in highly concentrated form in corresponding raw materials, e.g. sugar in syrup.

[0037] Another possibility is the addition of functional ingredients, such as flavors, and / or additional protein or amino acid sources to adjust specific properties or improve human biocompatibility. Generally, the additional mixtures, as well as one or more of the above-mentioned substances, are referred to as additional ingredients or additional components.

[0038] Definition of basic mixture

[0039] A base mix is ​​a combination of a protein mixture, whether from a single plant species or mixtures of several plant species, as plant protein isolate, plant protein concentrate, or a combination thereof, and water added before or during processing. Optionally, additional protein mixtures and / or at least one other ingredient and / or at least one other component can be added.

[0040] When water is added, the resulting mixture forms a dough, which is then further processed in an extruder. Alternatively, the individual components can also be added to the extruder during extrusion.

[0041] The base mix is ​​generally specified in % by weight, based on the weight of all added ingredients. A base mix of 50% protein mix and 50% water is thus created by mixing equal parts of the protein mix and water. However, the total water content in the base mix is ​​slightly greater than 50% because the protein mix itself contains some residual moisture. The same applies to salts, sugars, and fats added to the base mix, as these are also present in the protein mix in varying amounts.

[0042] Accordingly, the individual components in the base mix are slightly offset in terms of their added proportions. This is especially true with regard to the water content, which is usually somewhat higher than the pure water added due to the residual moisture in the protein mixture in the dough, but may be lower in the finished textured product because some of the water has evaporated.

[0043] Definition of extrudate

[0044] In the following, the dough mass produced in the extruder, particularly by kneading, which is subsequently stretch-formed, is referred to as the extrudate or also as the viscous or highly viscous mass. The texturate then corresponds to the finished stretch-formed and otherwise processed extrudate.

[0045] Definition of fiber

[0046] Fibers within the meaning of this application are elastic, cohesive layers that are aligned along a main direction, referred to as the fiber direction. Fibers within the meaning of this application exhibit strong anisotropy, which means that they can be detached or separated from the rest of the product if the fibers are pulled in a direction other than their fiber direction (e.g. from the transverse direction when they are aligned lengthwise, or vice versa). The fibers are therefore relatively loose or detachable if they are pulled in a direction orthogonal to the fiber direction, and elastic and cohesive if they are pulled along the fiber direction. Individual fibers can be detached from the product simply by pulling with the hand.

[0047] Fiber length is defined as the maximum length of the layer that detaches from the product without tearing, while retaining its strong anisotropy and elasticity along the fiber direction. The average fiber length is usually smaller and follows a normal distribution. Unless otherwise stated, the fiber length generally refers to the average fiber length.

[0048] Definition of thermomechanical treatment

[0049] A process during extrusion in which the dough is exposed to a specific temperature range while being mechanically processed. Mechanical processing may include kneading, rolling, rolling, crushing, and other forms in which a force or torque is applied to the dough.

[0050] Definition of axial and transverse strain

[0051] The deformation of the material along the longitudinal (axial) and / or lateral (transverse) axis, which occurs in a nozzle channel mounted after the screw section of the extruder. The material is thereby stretched along the respective axis. If the stretching occurs after the extruder exit, the extrudate is stretched accordingly.

[0052] Definition of material temperature

[0053] The temperature reached by the protein mixture during thermomechanical treatment in the extrusion process. Unless otherwise stated, the temperatures given refer to the material temperature.

[0054] The inventor has recognized that tensile stresses occurring during the processing of plant proteins are more efficient in deformation than shear forces. Suitable control of the occurrence and strength of these forces enables the production of fibrous structures in protein mixtures which are not sufficiently texturized in conventional systems due to insufficient deformation of the matrix. In particular, it is proposed to exploit strong longitudinal and / or transverse tensile stresses with respect to the extrusion direction in order to produce fibrous structures in plant protein-based extrudates at both medium (<50%) and low moisture content (<30%). The proposed principle allows the anisotropy of the texturate to be adjusted, unlike conventional methods, so that it is possible to apply the technique to all types of protein sources and their mixtures.Accordingly, for example, fiber lengths of 1 cm to 30 cm can be produced on average.

[0055] By adjusting the viscoelasticity, for example, through a suitable selection of ingredients and / or deformation stresses during the individual processes, even protein mixtures that would otherwise be difficult or impossible to texture can be textured. This creates a basis for texturing a wide range of proteins (including concentrates), and the texture can be tailored to the requirements of the final product. This makes it possible to create vegan products that resemble fish, chicken, beef, or pork in texture and flavor.

[0056] The proposed process is based on a combination of a base mixture comprising one or more protein mixtures, secondary components, and water, which is extruded at a dry to medium moisture content (10% by weight to approximately 40% by weight) and at relatively high material temperatures. To produce the texturate, a specially shaped die is used, in particular without cooling, to generate continuous elongational deformation which leads to fiber formation according to the invention. By applying the elongation-dominated flow, or more precisely sliding, a longitudinal or transverse velocity component of the hot mass in the die is generated due to a changing shape and / or a decreasing cross-section.The use of different materials as wall material makes it possible to adjust the contribution of shear stresses, which in some cases can be reduced almost to zero by using a PTFE or ceramic wall. Stainless steel has a significantly higher coefficient of friction in this regard, so there is a risk of wall adhesion, resulting in fiber breakage and short fibers. To enable sliding in this case, it is advisable to further increase the viscosity of the material.

[0057] This reduces the risk of flow instabilities in the die and enables very well-defined deformation through longitudinal and / or transverse stretching of the extrudate. This means that both longitudinal and transverse stretching stresses can be generated, primarily through the die geometry. The term longitudinal stretching stress refers to stretching stress that is essentially parallel to the direction of advance. Transverse stretching is stretching that is mainly perpendicular or transverse to the direction of advance of the extrudate. In addition, the temperature in this process is in some aspects above 100 °C and the pressure inside the die is also more than 5 bar and sometimes more than 10 bar. The resulting texture has a meat-like characteristic due to a fibrous structure whose length is greater than 8 cm and in particular greater than 12 cm and sometimes up to 30 cm.The water content of the texturate is in the range of less than 40% by weight, in particular less than 30% by weight.

[0058] At the exit of the expansion die, a direct-expanded texturate is formed, which can be used after rehydration or after rolling to collapse the pores and produce compact fibrous end products.

[0059] Not only can various protein mixtures be textured in this way, but it has been surprisingly discovered that protein mixtures that cannot be textured into long fibers or a long-fiber, meat-like structure under normal conditions can be used. Through further processing, the fibrous structure of the textured product can then be adapted to a desired end product.

[0060] Under conventional manufacturing techniques, however, the expansion would destroy the fibrous structures, but here the resulting product structure is very stable due to the long fiber formation and the high viscoelasticity, the evaporation and expansion at the exit of the expansion nozzle only leads to a loose and delicate product but with intact fiber structure.

[0061] The type of tensile stress, i.e., longitudinal and / or transverse stress, can be determined by the nozzle geometry. The extent of the longitudinal and / or transverse tensile stress can be adjusted by varying the wall material (PTFE, ceramic, or stainless steel) and by varying the design parameters listed in this application. This includes, among other things, the shape of the inlet cross-section, the shape of the outlet cross-section, and the transition thereto. In this way, the type and intensity of the tensile stress can be adjusted, allowing even protein mixtures that are otherwise difficult to produce to be textured.

[0062] In the method for producing a texturate, a base mixture is provided which comprises a protein mixture. The protein mixture has at least a first protein mixture, in particular one or more of an oat protein mixture, a wheat protein mixture, a pea protein mixture or a field bean protein mixture, with a weight proportion of between 40% by weight and 90% by weight, based on a base mixture. Other possible proportions would be 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight and 80% by weight and, above all, the respective ranges between two of these values, for example between 45% by weight and 50% by weight, in each case based on the base mixture.

[0063] In some aspects, the base mixture can also contain several different protein mixtures, in particular vegetable protein mixtures from different plant species. In some aspects, this can also include wheat. A second vegetable protein mixture can, for example, have a proportion of between 5% and 35% by weight based on the base mixture. Other possible proportions are 10%, 15%, 20%, 25%, 30%, 45%, and 50% by weight, and in particular the respective ranges between two of these values, e.g. between 10% and 15% by weight. In general, the second protein mixture should not have a larger proportion of the base mixture than the first protein mixture.

[0064] One or a combination of the legume proteins mentioned above, including soy, can be used as proteins. Mixtures of one or more legume proteins and another protein mixture, in particular a non-legume protein mixture, can also be used. These mixtures are also available as concentrates or isolates, so that the pure protein content in the texturate is usually somewhat lower. During the process, water is added to the protein mixture in a proportion by weight of between 10% and 50%, based on the basic mixture to form a dough. Other possible proportions of water that can be added are 10%, 15%, 20%, 25%, 30%, 35%, 40% and 45%. In some aspects, the protein mixture in the base mixture may already have an increased residual moisture content.This is taken into account when adding water, so that the total proportion of water in the dough is in some aspects less than 55% by weight, but in particular less than 50% by weight and in particular less than 45% by weight, less than 40% by weight or even less than 35% by weight based on the dough mass.

[0065] The water can be added before kneading, but also during kneading and forming the dough in an extruder. In other words, in some aspects, the base mix can be poured into an extruder, and the water is added separately. In other aspects, the water is partially or completely added to the base mix, and the resulting dough is then added to the extruder for further kneading.

[0066] The method further comprises the step of extruding the dough at a maximum temperature in the range between 110 ° C and 160 ° C, but in particular between 120 ° C and 145 ° C. The term extrusion in this regard means kneading the dough under increased pressure and the above-mentioned temperature, whereby the dough is usually kneaded and driven forward by one or more screw or similar gears. The dough mass is thus extruded at a low moisture content of less than 50 % by weight (down to just over 10 % by weight), but at the above-mentioned high temperatures, so that it can be referred to as dry extrusion or slightly moist extrusion. Due to the lower water content at a medium to low level, the dough mass has a highly viscous, highly elastic matrix in the screw section of the extruder compared to other production processes.The resulting highly viscous but simultaneously highly elastic matrix is ​​then subjected to extensional deformation at a temperature of greater than 90°C and in particular greater than 100°C. This is achieved by forcing the hot, highly viscous mass through a special extension nozzle, which does not require separate cooling. The special extension nozzle is characterized in that an area of ​​its inlet cross-section is larger than an area of ​​its outlet cross-section and, in particular, a length is significantly larger than a maximum diameter of the inlet cross-section, or else that a diameter in one direction differs from a diameter in another direction between inlet and outlet.

[0067] According to the proposed principle, the strain deformation mentioned above occurs either in a longitudinal direction, i.e. along the advance, and / or in a transverse direction, i.e. perpendicular to the advance. This is also referred to as longitudinal strain or transverse strain, whereby transverse strain can occur in two directions. A combination of such strains can be adjusted, for example, using the parameters mentioned above, including a suitable choice of wall material and nozzle geometry. The strain stresses occur, among other things, through the extrudate sliding along the wall, so that little or no shear flow occurs. It is particularly important here that the viscosity of the highly viscous mass should not be too low, since otherwise the required strains cannot be generated.

[0068] In this way, the continued elevated temperature, in particular above the evaporation temperature of water, and the existing pressure result in long, connected fibers resembling a meat structure due to continuous stretching and the resulting tensile stresses. The stretched extrudate leaves the die as a texturate, with a sudden drop in temperature and pressure occurring in some aspects. Due to a not necessarily homogeneous distribution, the expansion leads to a localized, water-rich phase (also referred to as the soft phase), which creates the anisotropy according to the invention. Evaporation makes these water-rich, soft phases even looser. In some aspects, the added protein mixture and water are kneaded at an increasing temperature up to the maximum temperature. The maximum temperature can also be maintained during further kneading of the dough.The temperature and pressure increase occur continuously in some aspects, but can also be discontinuous, i.e., with periods of advancement during which no further heating takes place. The transition from a slurry (usually with a higher water content) to a dough is fluid, with the latter, in particular, representing a kneaded and mechanically almost inseparable mass of the basic mixture and water.

[0069] The maximum temperature in some aspects is in the range of 110°C to 160°C, and more particularly between 115°C and 135°C, and more particularly between 120°C and 145°C. Other temperature ranges for the maximum temperature would be 112°C, 114°C, 116°C, 118°C, 120°C, 122°C, 124°C, 126°C, 128°C, 130°C, 132°C, 134°C, 136°C, 138°C, 140°C, 142°C, 144°C, 146°C, 148°C, 152°C, and 154°C. The temperature can be continuously increased to the maximum temperature during kneading and extrusion of the dough or mass and then held constant. In some aspects, the temperature increase is designed so that the maximum temperature is reached approximately halfway through an extruder section. Likewise, the temperature can be changed several times during the extrusion process, so that different temperatures are set in different sections. Likewise, the pressure increases to a maximum value during kneading and extrusion.Accordingly, in some aspects, extrusion is envisaged to occur at a pressure in the range of 1 bar up to 100 bar or more. Typical ranges are between 20 bar and 80 bar, and in particular less than 60 bar at the end of the extruder.

[0070] By varying the thermal stress profile during extrusion, the degree of protein-protein interactions and polymerization reactions is varied, allowing the elasticity and viscosity to be adjusted to a further extent. This aspect is not only achieved in the extruder itself (i.e. during kneading of the dough), but also to a lesser extent during stretching. In some other aspects, a gas is added during kneading, i.e. in the screw section of the extruder, in order to loosen up the dough and also the subsequent extrudate. The gas can be added at one point in the screw section of the extruder, for example in the initial area of ​​the extruder, but also at different points. In some aspects, the gas is added at a pressure that is later increased during extrusion, particularly in the screw section. This "dissolves" the gas in the extrudate material and remains bound in the material.Only during the subsequent elongation deformation, and especially at the end of the texturized material exit, does the pressure decrease again, allowing the gas to contribute to the loosening of the extrudate. The gas used for this purpose can be carbon dioxide, nitrogen, and, in some cases, nitrogen.

[0071] In some cases air can also be used.

[0072] In some cases, a gas-generating material can be added to the dough. This material decomposes during further processing, particularly during the kneading in the extruder, and thus contributes to gas formation. A typical such material is baking soda (sodium bicarbonate), which decomposes with citrates or other mild acids to form carbon dioxide. Both substances can be added to the basic mix initially as dry materials and only begin to react when water is added. If the water is added in the screw section of the extruder, premature escape of the gas is also prevented. In some applications, only baking soda is added, and during kneading, due to the high temperature, it decomposes back into carbon dioxide and sodium carbonate.

[0073] In the proposed method, in some aspects the expansion nozzle is not actively cooled, i.e. the expansion-deformed texturate leaves the expansion nozzle at a temperature of more than 100 °C. Likewise, the expansion deformation can take place at different temperatures, so that in some aspects the expansion deformation is divided into several steps, of which individual steps are carried out at different temperatures above 100 °C. During expansion deformation the flow velocity is increased, but the mass flow remains essentially the same. In the case of longitudinal expansion the flow velocity changes along the direction of advance, in the case of transverse expansion it changes perpendicular to this, i.e. the viscous mass is stretched in a direction transverse to the direction of advance.This stretching can be achieved, for example, by applying transverse strain deformation at temperatures greater than 100 °C by propelling the highly viscous mass, increasing the flow velocity in a direction perpendicular to the direction of propulsion. Alternatively, longitudinal strain deformation can be applied at temperatures greater than 100 °C by propelling the highly viscous mass, increasing the flow velocity in a direction along the direction of propulsion.

[0074] It is also possible for an advance speed to be at least partially lower than a flow speed in a direction perpendicular to the advance direction. This means that, for example, in some sections the mass is expanded faster than it is advanced. In some aspects the expansion can be influenced by coating the wall, reducing the diameter of the expansion nozzle or reducing the height to width and other parameters. The mass flow remains essentially constant and, due to the high viscosity, laminar. To prevent the tensile stresses from breaking, it is advisable to keep the static friction between the mass and the wall low so that the mass slides along it. By advancing the extrudate, the mass is strain-deformed at temperatures above 100 °C and in particular between 105 °C and 115 °C.At the end of this elongation deformation, the product temperature is still above 100 ° C in some aspects, for example, in the range between 110 ° C and 135 ° C. It can also exceed 130 ° C in special aspects.

[0075] Longitudinal or transverse strain deformation can occur continuously or in sections. In the first case, this is achieved, for example, by a continuous decrease in the cross-sectional area. In some aspects, instead of the cross-section, a ratio of width to height between the inlet and outlet is used, whereby the ratio also changes. In particular, one of the two quantities decreases between the inlet and outlet. Thus, transverse flows and strains can be generated in a targeted manner.

[0076] In the cases mentioned, this means that the flow velocity of the mass is increased in sections, followed by one or more sections in which the flow velocity is essentially constant. The increase in flow velocity can occur along or perpendicular to the direction of propulsion of the mass. Alternatively, the flow can be increased continuously so that extensional deformation occurs over a longer section, possibly even up to the exit of the extension nozzle. In some aspects, a transverse flow velocity (i.e. perpendicular to the propulsion flow direction) is determined by the ratio of the width of the inlet to the width of the outlet. Accordingly, the nozzle can also be short, provided that primarily transverse extensional stresses are generated.

[0077] In some aspects, the time the mass is propelled in sections of constant flow velocity is greater than the time the mass is propelled with increasing flow velocity.

[0078] Due to the low water content in the dough, its viscosity is higher than extrudates with a higher water content. The increased viscosity leads to greater extensional stresses due to the differences between the inlet and outlet cross sections. The length of the nozzle can also play a role. This is helpful in the aspects presented here in order to influence the speed of the mass flow through the shape, length and design of the extension nozzle. In some aspects, the length of the nozzle through which the viscous mass is propelled is at least a factor of 1 and in particular a factor of 3 to 7 greater than the maximum diameter of the inlet cross section or the greatest extent of the inlet. To generate transverse extensional deformations of the viscous mass, the length is changed in a first direction, perpendicular to the length of the nozzle width across the length of the nozzle, e.g.is increased , while the length in the direction perpendicular to the first direction and perpendicular to the length of the nozzle is reduced over the length of the nozzle . If at the same time the exit cross - section is reduced compared to the entry cross - section , longitudinal strains are also caused in addition to transverse strains .

[0079] Accordingly, it can also be provided to change the strain on the mass in at least two consecutive sections during the advance. This can improve fiber formation. A change in the strain can be achieved, for example, by changing the geometry, but also by changing the coating of the wall of the expansion nozzle. In some aspects, the static and / or sliding friction acting on the mass during the advance can also be changed, for example by changing the wall materials of the expansion nozzle. In this context, it is possible to design the sections during the advance in such a way that longitudinal strain stresses and transverse strain stresses act on the viscous mass in sections.

[0080] In some aspects, after strain deformation, the texturate is cooled to a temperature below 100°C. This can be done by flash relaxation, i.e. by releasing the pressure while cooling. Cooling can also begin somewhat later than the pressure release. The sudden pressure release, particularly close to a temperature of 100°C, such as at 105°C to 110°C, causes any remaining water within the strain-deformed matrix to suddenly evaporate and, in some aspects, leads to a loosening of the texturate.

[0081] Some further aspects deal with the base mix. In some aspects, salt is also added to the base mix to modify the water distribution in the texturate. Moisture otherwise tends to localize in the dispersed phase and therefore makes the continuous phase with less water harder. The added salt content can be up to 2% by weight in some aspects and in particular up to 1.5% by weight!. Likewise or alternatively, additional sugar can be added, i.e. sugar in addition to the proportions already present in the protein mix. In some aspects, the added sugar content is up to 15% by weight, although this amount again depends on the protein mix used. The sugars mentioned above can be used for this. The added sugar is used to replace the large, branched and reactive protein molecules with very small sugar molecules and thus reduce network formation.Possible sugars for this would be glucose, fructose, maltose, syrup, sugary fruit juices and others.

[0082] Other optional ingredients include oils and fats up to 10% by weight, flavorings up to 2% by weight, and colorings up to 2% by weight. The total amount of other ingredients is up to 25% by weight, but usually less than 20% by weight or less.

[0083] With the combination of additional sugar, salt and process parameters such as the temperature during kneading, the gel and bite strength of the matrix and thus of the texture can be adjusted to a desired range.

[0084] In downstream aspects, the texturate produced in this way can be further processed to improve its structure. Possible measures for this include mechanical aspects such as cutting, rolling, pressing, rolling, and the like, as well as drying the intermediate product, as well as deep-frying or coating. All of these measures serve to produce the final product from the texturate produced according to the proposed process.

[0085] Some further aspects relate to an extruder arrangement suitable for carrying out the method .

[0086] The extruder arrangement has a mixing extruder with an inlet zone for feeding in a base mixture, the base mixture containing at least a protein mixture and water and optionally further ingredients according to the aspects mentioned above. The mixing extruder also comprises a mixing zone and an output zone. The mixing extruder is designed to generate a temperature increase across the zones up to a maximum temperature of between 110 °C and 160 °C. Furthermore, an expansion nozzle is connected to the output zone of the mixing extruder and has a length, an inlet cross section and an outlet cross section. The inlet cross section can correspond to the shape and cross section of the output zone of the mixing extruder.

[0087] According to the proposed principle, an area of ​​the exit cross-section is smaller than an area of ​​the entry cross-section and the length is greater than a maximum extension of the entry cross-section in one direction. Alternatively, a reduction of height H to width B between the inlet and outlet of the nozzle is conceivable. Likewise, the expansion nozzle is configured to cause the extruded extrudate to reach a temperature of greater than 100 °C at its outlet. Thus, in the extruder arrangement according to the invention, the extrudate is subjected to longitudinal and / or transverse expansion deformation with, in comparison, little or no shear stress, so that targeted and in particular longitudinal or transverse fiber formation occurs in plant-based extrudates.

[0088] In some aspects, the mixing extruder comprises a two-axis worm gear, in which the supplied protein mixture and the water are formed into a dough at increasing pressure and temperature. In some aspects, the mixing extruder is designed to exert the temperatures and pressures mentioned above in the method. For this purpose, the mixing extruder can contain several sections arranged one behind the other, in which independently operable heating elements are arranged. In this way, various temperature profiles can be generated.

[0089] In some further aspects, an inner side of the expansion nozzle comprises a surface made of a fluoropolymer, in particular Teflon or a ceramic or a glass coating. As a result, in some aspects, the expansion nozzle is designed such that the extrudate essentially slides along an inner surface of the expansion nozzle. Alternatively, another temperature-resistant plastic that is also approved for food use can be provided, which has a different, in particular lower, friction or adhesive force than other materials. The surface can be provided with the corresponding plastic, but it is also possible to manufacture the expansion nozzle at least in sections from plastic.Accordingly, in some aspects, it may be provided that an inner side of a first section of the expansion nozzle comprises a first material, and an inner side of a subsequent second section of the expansion nozzle comprises a second material that differs from the first material. In a further embodiment, it is provided that sections of the expansion nozzle have different static friction.

[0090] In contrast to metals, plastics have significantly lower heat transfer. Accordingly, in some aspects, in sections where the surface is provided with plastic, the temperature of the extruded material will drop less than in sections with a metallic surface. In particular, in some aspects, the expansion nozzle is designed such that the temperature of the extruded material remains essentially constant in these sections. The maintained temperature can in particular be in the range between 110°C and 160°C, in particular between 115°C and 135°C, in particular between 120°C and 145°C, in particular between 115°C and 125°C, in particular between 110°C and 120°C, in particular between 120°C and 135°C, in particular between 120°C and 130°C, in particular between 125°C and 135°C and in particular between 130°C and 140°C.

[0091] In some aspects, the maximum temperature in at least one of the zones is in the range between 110°C and 160°C, and in particular between 115°C and 135°C, and in particular between 120°C and 145°C. Other temperature ranges are between 110°C and 120°C, 115°C and 125°C, 120°C and 130°C, and between 125°C and 135°C. The temperature ranges depend in some aspects on the protein mixture used.

[0092] Some aspects concern the shape of the inlet cross-section of the expansion nozzle and the outlet cross-section of the nozzle. For example, the inlet cross-section of the expansion nozzle can have the same shape as the outlet cross-section. In some aspects, the expansion nozzle is directly connected to the extruder's discharge zone, with their cross-sections being the same. However, it is possible to couple the extruder and expansion nozzle via a short coupling piece, provided the coupling is significantly shorter than the expansion nozzle. Such a coupling piece can have different inlet and outlet cross-sections, thus connecting the extruder and expansion nozzle.In other aspects, the expansion nozzle has a maximum inlet width and a maximum outlet width in a first direction, and a maximum inlet height and a maximum outlet height in a second direction perpendicular thereto, wherein a maximum outlet width in the first direction is greater than the maximum inlet width in the first direction and the maximum inlet width in the second direction is less than the maximum outlet width in the second direction.

[0093] In some embodiments, the expansion nozzle has a continuous decrease or reduction of the area of ​​the inlet cross-section to the area of ​​the outlet cross-section, or a continuous decrease of the ratio between the input ratio HEngang / B E input and the output ratio H AuS gang / B AuSgang • In some other aspects, the expansion nozzle has at least a first section with a constant cross-sectional area, at least one subsequent second section with a decreasing cross-sectional area and at least one subsequent third section with a constant cross-sectional area. In addition, a material of a section with a constant cross-sectional area can be different from a material of a section with a decreasing cross-sectional area. In some aspects, as already mentioned, the nozzle becomes thinner and wider over its length so that, in this way, primarily transverse expansion stresses are built up. Here, too, there can be widenings in certain sections so that the nozzle has sections with a constant cross-sectional area or height.The length of the nozzle can in some cases be designed such that the length lies in the range between one and three times the greatest width or height. However, in some aspects the nozzle and also the method are designed such that the nozzle geometry does not lead to a sudden drop in pressure, i.e. the volume of the nozzle does not suddenly increase over the length, so that the mass can expand. This avoids breakages. In some aspects it is further provided that the at least one first section has the inlet cross-sectional area or the inlet cross-section and the at least one third section has the outlet cross-sectional area or the outlet cross-section, wherein optionally a length of the at least one first and / or the at least one second section is greater than the maximum dimension of the inlet cross-section or the outlet cross-section in one direction.In this context, there may also be several second sections, which in turn may be designed differently, i.e. with constant or decreasing sections.

[0094] In further aspects, the expansion nozzle is designed with an outlet cross-section which, in plan view, has the shape of a circular ring, wherein an inner part surrounded by the circular ring is formed by a body, in particular a cone, which tapers towards the inlet cross-section. The term circular ring is understood below not only to mean a completely round circular ring (i.e. with a center point and constant radius), but also a circular ring which has an oval shape or two interconnected circular segments. Other shapes, up to and including a rectangular or square frame, possibly with rounded corners, are also to be considered, for the sake of simplicity, to be covered by the term circular ring for the purposes of this application.

[0095] In another aspect, the expansion nozzle has an outlet cross-section which, in plan view, has a plurality of openings arranged around an inner part, in particular of the same cross-section, wherein the inner part has a body tapering toward the inlet cross-section. In these embodiments, the tapering body is designed such that a cross-section through the material of the body decreases continuously toward the inlet cross-section of the expansion nozzle.

[0096] In this context, for the above-mentioned embodiment, the inner part can be arranged with a central opening, the cross-section of which optionally differs from the cross-sections of the openings surrounding the inner part. Finally, in some aspects, a cooling nozzle or cooling tube can also be provided, which is connected to the outlet of the expansion nozzle and configured to cool the expansion-formed textured material to below 100°C.

[0097] Further advantages of the process and arrangement presented here include the ability to adjust the stretching stress through the nozzle geometry, as well as the processing of various proteins that were previously difficult to texture. Dry, durable texturates can be produced, which, thanks to their long-fiber structure, can be further processed in a variety of ways. Another advantage is the more efficient use of energy, since the stretching nozzle, unlike conventional manufacturing processes, does not require cooling, which also simplifies scalability.

[0098] BRIEF DESCRIPTION OF THE DRAWINGS

[0099] Further aspects and embodiments according to the proposed principle will become apparent with reference to the various embodiments and examples which will be described in detail in conjunction with the accompanying drawings.

[0100] Figure 1 shows a mixing extruder as it can be used for the proposed process and the extruder arrangement according to the proposed principle;

[0101] Figure 2 shows a first embodiment of an expansion nozzle in cross-sectional view according to the proposed principle;

[0102] Figures 3A and 3B show two further designs of expansion nozzles according to the proposed principle;

[0103] Figures 4A and 4B show two further designs of expansion nozzles according to the proposed principle in cross-sectional view;

[0104] Figures 5A and 5E show further embodiments of expansion nozzles according to the proposed principle; Figures 6A and 6B are two embodiments of methods for producing a textured article according to the proposed principle

[0105] Figure 7 shows an excerpt from a simulation to illustrate transverse strain stresses.

[0106] DETAILED DESCRIPTION

[0107] The following embodiments and examples show various aspects and their combinations according to the proposed principle. The embodiments and examples are not always true to scale. Likewise, various elements may be shown enlarged or reduced in size to emphasize individual aspects. It goes without saying that the individual aspects and features of the embodiments and examples shown in the figures can easily be combined with one another without thereby impairing the inventive principle.

[0108] Furthermore, the individual figures, features, and aspects are not necessarily shown in the correct size, and the proportions between the individual elements may not always be correct. Some aspects and features are emphasized by being shown enlarged. However, terms such as "top", "above", "below", "below", "larger", "smaller", and the like are correctly represented with reference to the elements in the figures. This makes it possible to infer such relationships between the elements from the illustrations.

[0109] Figure 1 shows part of an extruder arrangement according to the proposed principle. The extruder arrangement is designed with a mixing extruder 1 with a twin worm gear, in which the fed mass is kneaded by means of two worm gears and driven forwards towards an outlet of the mixing extruder. For this purpose, the mixing extruder 1 comprises a motor with a gear 10, to which the two worm gears are anchored. Connected to this are a plurality of sections 11a, 11b, 11c, 11d and 11e of the mixing extruder. The respective sections are mechanically tightly connected to one another via flanges or in some other way. In this way, the mixing extruder shown can either be lengthened by adding individual sections or shortened by removing them.The screw sections 12a, 12b and 12c are designed in a corresponding manner so that they can also be lengthened or shortened by adding or removing individual screw elements.

[0110] In particular, the mixing extruder 1 according to the proposed principle comprises two inlet sections 11a with associated screw elements 12b. The inlet sections 11a each have an opening for supplying the base mixture or water. In detail, in the illustrated embodiment, the base mixture is fed via a hopper 14 into a first section 11a of the mixing extruder 1. Subsequently, the water is also added via an inlet 15, so that the two first extruder sections 11a primarily serve for a first mixing to form a dough from the water and the supplied base mixture.

[0111] Connected to the first sections 11a are a plurality of further sections 11b, 11c, and 11d, some of which are filled with different screw elements 12a. As can be seen in Figure 1, the screw elements serve both to advance the dough and to knead it while increasing the pressure and temperature.

[0112] For this purpose, the individual sections are equipped with several heating elements (not shown here) which can be controlled separately and independently of one another. This means that different temperature profiles and thus different temperatures of the advanced dough can be set in the individual sections 11a to 11e. Furthermore, the individual screw elements in the respective sections are also designed differently. Some screw elements are used to knead the mass from the base mixture and the added water in order to produce a dough with a continuous phase. At the same time, the pressure in these areas is increased to between 15 and 20 bar through the kneading and the further advancement of the added base mixture. In addition, feeds for gases can be provided in other screw elements, which serve to add a gas to the dough during kneading to loosen it.The supplied gas is bound by the pressure in the screw section of the extruder. The feed is controlled and occurs at one or more points during kneading to ensure an even distribution of the gas throughout the dough.

[0113] With a simultaneous increase in temperature, or a high temperature, for example, in the range of 120°C to 160°C, and a pressure of several bar, polymerization of the protein mixture with the water and the other components occurs, resulting in a gel-like, highly viscous mass. This mass is kneaded in different ways by the individual screw elements 12a and propelled in small pieces to an exit section 11e of the mixing extruder 1.

[0114] The outlet section 11e of the mixing extruder 1 has a slightly conical shape on the outlet side with an ejection zone 13 to which an expansion nozzle according to the proposed principle is connected either directly or via an intermediate piece. However, for reasons of clarity, this is not shown but is explained in the further figures 2 to 5B in some exemplary embodiments. The dough mass located in this outlet section is thus pressed under high pressure in the range of several bar, for example up to 25 bar, through the ejection zone into the expansion nozzle and there is subjected to elongation deformation by a uniform forward propulsion.

[0115] Figure 2 shows such an embodiment of an expansion nozzle according to the proposed principle for explaining some aspects of the invention. The expansion nozzle 20 comprises an expansion body 21 with an inlet region 23 and an outlet region 24. The inlet region 23 has a diameter or an area that is significantly larger than the diameter or the area of ​​the outlet region 24. The shape of the inlet region 23 and the outlet region 24 can be shaped differently, for example as shown in Figure 2 here, either completely circular, but also round-ended or oval-shaped.

[0116] The inlet region 23 is connected either directly to the discharge zone of the mixing extruder 1 or via a tubular intermediate piece 30 to the discharge zone 13. In the present exemplary embodiment, the expansion nozzle comprises an inner region which is referred to as the expansion section 22 and is characterized by a cross-section which continuously tapers at the same gradient over the length L of the expansion nozzle. In other words, the diameter (or radius) Ri and the respective area in the inlet region 23 are continuously reduced over the length of the expansion nozzle down to the cross-section R2 and the respective area of ​​the outlet section 24. In the cross-sectional view of the nozzle 20 shown here, the tapered part thus forms a parallelogram with the two parallel sides corresponding to the inlet section 23 and the outlet section 24.Viewed three-dimensionally, it is a truncated cone, whereby the respective base and end surfaces can be either circular or round-ended with a conical inlet, as shown.

[0117] The length L of the expansion nozzle is at least three to four times the diameter Ri in the inlet area. Due to the tapered cross-section here, the flow velocity of the dough is continuously increased at a constant mass flow rate as it advances through the expansion nozzle 20. In the exemplary embodiment, the flow velocity also increases evenly due to the uniformly decreasing cross-section.

[0118] In order to achieve a constant mass flow, this means that the flow velocity depends on the radius of the inlet and outlet areas and on their areas. If, for example, the inlet area has an area that is three times as large as the area of ​​the outlet area, the flow velocity in the outlet area must also be increased accordingly by a factor of three to ensure the same mass flow. Due to the increasing flow velocity, the advanced dough mass is stretched parallel to the direction of advance. As a result, elongated fiber structures form at the continued high pressure of over 7 bar and the high temperature in the expansion nozzle of over 100 °C.The uniform taper, which can be controlled in particular by adjusting the length of the expansion nozzle as well as the inlet and outlet cross-sections, prevents wall slippage and shear stress, which leads to tearing of the excavated mass.

[0119] In another aspect, the coating of the inside of the expansion nozzle can also be provided with a special low-friction material. In addition to stainless steel, which is used in food production, among other applications, a plastic such as Teflon can also be considered. This material is particularly low-friction, so that the dough being advanced is subjected to greatly reduced or almost non-existent shear stress at the edge. This creates long fibers in the dough along the direction of advance.

[0120] Depending on the proteins used and the base mixture for the extrudate, different elongation stresses are required to prevent material breakage. It may also be necessary to allow the extruded mass to "rest" for a while after elongation so that the fibers can align. Accordingly, the elongation dies can also be designed differently with multiple sections. Figures 3A and 3B show two such embodiments, in which the elongation die is formed from various rest sections and sections with elongation deformation.

[0121] Figure 3A shows an expansion nozzle 20 with a nozzle body 21, which has a round inlet area 23 on the inlet side and a correspondingly round outlet cross-section 24 on the outlet side. In this embodiment, the diameter Ri of the inlet cross-section is approximately four times as large as the diameter R2 of the outlet cross-section 23. This results in the area of ​​the inlet section being given by Ri 2 n = ( 8R2) 2 n is therefore approximately 16 times the area of ​​the outlet section. It follows that the flow velocity at the outlet must also be approximately 16 times that at the inlet of the expansion nozzle to ensure the same mass flow.

[0122] The expansion nozzle of Figure 3A comprises several sections in its interior. On the inlet side, a first section 25d is provided which is essentially cylindrical and in which the area of ​​the inlet cross section remains constant over the length of section 25d. Connected to this is a first expansion section 25a, in which the area of ​​the inlet cross section Ri is reduced to a smaller area of ​​the cross section R3. In this first expansion section, the flow velocity thus increases while the mass flow remains constant, and the dough being forced forward is subjected to a first expansion stress. The area in the outlet region of the first expansion section is approximately M the area of ​​the inlet region 23; the flow velocity will therefore accelerate fourfold.

[0123] Subsequently, the dough, thus stretched, is advanced over a second cylindrical section 25c. In this section, the diameter and thus also the cross-sectional area and thus the flow velocity are again constant, so that the dough undergoes a certain rest phase during the advance.

[0124] Connected to this is a second expansion section 25a, in which the inlet side diameter R3 and thus the area is reduced again to the outlet side diameter R4. This reduction is somewhat smaller, so that the flow velocity does not increase as much as in the first expansion section, but for example only by twice as much. Also connected to this is a further rest section 25c, which in turn is followed by a final expansion section 25a. In this, the inlet side diameter R4 is now narrowed to the outlet side diameter R3, and the flow velocity increases again slightly with the mass flow remaining the same. A further rest section 25e of the expansion nozzle 20 is now arranged on the outlet side, in which the extruded, stretch-deformed material is extruded again. The section 25e forms the end section, at the outlet 24 of which the mass emerges from the nozzle.

[0125] The expansion sections 25a present here are each designed with a different gradient, with the first expansion section on the left having the greatest reduction in diameter (from Ri to R3) and thus in its cross-sectional area. Accordingly, the flow velocity increases particularly sharply here, whereas in the following expansion sections it increases somewhat less in each case (e.g. by a factor of 4 in the first expansion section, and then by double in each case). The different sections 25d, 25c and the exit section 25e serve primarily to ensure that the dough being forced forward can rest between the individual expansion sections and that no further expansion stress is exerted on it.

[0126] In this context, it may be advisable to coat the inside of the expansion sections with a suitable material to further reduce friction and adhesion of the dough to the inside of the expansion sections. This further reduces potential shear forces, particularly in the area of ​​the tapered sections, so that only the expansion stress due to the decreasing cross-sectional area acts on the dough as it is forced forward.

[0127] Figure 3B shows a further embodiment of such an arrangement in which the expansion sections are significantly longer than the rest sections, in contrast to the embodiment in Figure 3A. In the embodiment, the inlet region 23 and also the outlet region 24 of the expansion nozzle are no longer circular, but rectangular. However, other inlet cross-sectional shapes and outlet cross-sectional shapes are also possible in this context; moreover, the shape of the inlet cross-section can also be selected to be different from the shape of the outlet cross-section, so that during the expansion sections or also the rest sections the shape changes accordingly. This change is designed in such a way that as little shear force as possible is exerted on the dough mass as the dough is forced forward due to the change in shape, but rather the dough is mainly subjected to expansion deformation.

[0128] The inlet section 25d of the expansion nozzle 20 in Figure 3B is followed by a conically tapered and narrowing first expansion section 25b. In this section, the outlet diameter R3 is approximately one third as large as the inlet diameter Ri. The first expansion section 25b is designed with a continuous taper in the direction of the outlet region 24 and has a length LI that is greater than the first rest section 25d in the inlet region of the expansion nozzle and also a second rest region 25c adjoining the outlet of the first expansion section. This second rest region 25c is short, only one fifth to one quarter of the length of the expansion section 25b, and then merges into a second, shorter expansion section 25b. On the outlet side, this expansion is in turn connected to a further rest section 25e, which simultaneously forms the outlet region 24.

[0129] The three exemplary embodiments demonstrate that, depending on the implementation, the length of the expansion sections can be selected differently from the possible rest sections. The taper in the respective expansion sections depends on the extrudate used and its ability to form long-fiber structures when a tensile stress occurs.

[0130] If the extrudate has a lower viscosity, it is advisable to reduce the cross-sectional area over a longer distance and thus subject the extrudate to only low tensile stresses so that the extruded extrudate does not tear off and lead, for example, to wall slippage or warping. Extrudates made from dough with a higher viscosity, on the other hand, can be stretched to a greater extent without wall slippage occurring. Accordingly, shorter stretching sections or stretching sections with a greater taper could be provided here so that the flow velocity is increased while the mass flow remains the same. Rest sections between individual stretching sections serve to relax the extruded extrudate somewhat and thus prevent the extrudate from tearing off and the production of shorter fibers.

[0131] In some aspects, the material should be output as a texturate, whereby the texturate as a single strand should only have a small volume at each exit. This is particularly the case when the extrudate travels with too large a volume and corresponding tensile stress, thus leading to wall slippage or warping. This can occur if the tensile deformation is large at the edge of the expansion die, but is still too small inside the propelled extrudate mass. In the laminar flows present here, shear forces can occur particularly in the interior, which impair long fiber formation.

[0132] Figures 4A and 4B show an embodiment for preventing such a break, in which the expansion nozzle 20 has a conical body 30 in the outlet region 24. This conical body is designed as a cone, the truncated cone of which terminates at the outlet region 24 and the tip of which points in the direction of the inlet region 23 with its diameter RI.

[0133] In the embodiment of Figure 4A, the cone is designed such that its cone tip ends within the expansion nozzle. In other words, the expansion nozzle is divided into two sections. The inside of the expansion nozzle is designed such that the side walls of the expansion nozzle taper continuously at a constant gradient over the entire length L. A second region 25B adjoining the first section 25a contains the cone 30. The gradient dx / dy is defined as the decrease in diameter towards the exit region.

[0134] The slope of the cone 30 in the direction of the outlet region 24 is slightly greater than the corresponding taper of the inner side surfaces of the expansion nozzle 21. In this exemplary embodiment, a greater expansion stress is therefore built up along the inner side of the cone surface than on the outlet side. This means that the extruded mass, which moves along the cone surface, experiences a slightly greater expansion stress than the material on the other side. The first section 25a is important here, however; in this section, the extrudate is stretched as a volume material, primarily in its edge region, while an inner region of this mass is only deformed to a greater extent by the conical surface of the cone 30 during propulsion.

[0135] With this arrangement it is thus achieved that the tensile stresses on both sides of the extrudate along the inside of the expansion nozzle and along the conical surface of the body 30 are essentially the same.

[0136] In an alternative embodiment, the cone tip can be shifted toward the inlet area, so that the overall slope of the cone surface is reduced. With such a design, the rising interior of the expansion nozzle and the slope of the cone surface can be adjusted accordingly.

[0137] In a further exemplary embodiment, the tip of the conical body 30 is in the same plane as the inlet region 23 with its diameter Ri. This embodiment is shown as an example in Figure 4B, wherein the inner surface of the expansion nozzle 20 is now formed by a tube with a constant cross-section. The expansion of the dough is now generated by the gradient of the conical body 30 (i.e. the increasing cross-section of the conical body) over the length of the expansion nozzle. In this exemplary embodiment, too, the coating of the conical body 30 can be different from the coating of the inside of the expansion nozzle 20, so that wall slippage and shear forces occurring during movement are reduced as much as possible.

[0138] In both embodiments, a knife or similar mechanical device can be arranged at the outlet of the expansion nozzle. This knife cuts open the circularly ejected textured material and transports it further along a conveyor belt. The ring diameter in the outlet region depends on the base area of ​​the conical body and the inner diameter of the respective expansion nozzle 20. With a constant mass flow, this results in an increase in the flow velocity and a resulting expansion stress, which essentially depends on the area of ​​the outlet side compared to the area of ​​the inlet side of the expansion nozzle.

[0139] In some further aspects, it is conceivable to squeeze the matrix mass not as a complete ring or as a complete material, but in the form of several noodle-like strands. This has the advantage that the total surface area of ​​the squeezed-out material is larger relative to the volume compared to other embodiments.

[0140] Figures 5A and 5B each show such an embodiment. In Figure 5A, a first section 25d is connected on the inlet side to the discharge zone of the mixing extruder. The inlet section 25d has a uniform diameter or cross-sectional area up to a second section 25b. Introduced into this section is a conical body 31, the tip of which coincides with the interface between the two sections 25d and 25b. The conical body 31 opens towards the outlet side 24, wherein in the cross-section here too, similar to that in partial Figure 4A, openings are present between the inside of the expansion nozzle 20 and the conical body 31. In plan view, these openings are implemented by a plurality of smaller circular outlet openings 24. In this way, the advanced extrudate is stretched in the region of the section 25b by the slope of the conical body 31 and then pressed through the plurality of circular openings 24.

[0141] Figure 5B shows a further embodiment in which the conical body 31 is replaced by a more complicated shape 31a. In addition, the inlet-side section 22 has a tapered cross-section from the inlet cross-section Ri to the section cross-section R3, to which the body 31a adjoins. Here, too, a plurality of circular outlet openings are provided in the region 24 through which the material passes. The elongation deformation in this second section 26 is increased due to the additional body 31a and, in particular, mass elements of the extruded extrudate are also subjected to elongation deformation which are arranged centrally in the middle of the extrudate in the first section 22 and thus experience only slight deformation.

[0142] The various expansion nozzles of the form presented here are suitable for producing longitudinal fibrous structures in an extrudate and making this available as a texturate for further processing.

[0143] The various shapes and the strength of the expansion deformation can be adjusted using a corresponding geometry based on the length of the expansion nozzle and the individual cross-section. This makes it possible to texture even materials that tend to tear or break if stretched too far.

[0144] In this embodiment, the stretching nozzle is distinguished primarily by the fact that its length is significantly increased compared to its inlet or outlet cross-section. Furthermore, it can have several shorter or longer stretching sections as well as resting sections in which the dough is not stretched further or only slightly in the longitudinal direction. Furthermore, it is generally possible for the stretching nozzle to comprise additional heating or cooling elements in order to be able to generate different temperatures in the individual sections if necessary.

[0145] Figures 5C to 5E address a further aspect, namely that the input cross-section does not reduce uniformly (although in sections), but the input reduces in one preferred direction, whilst in the other direction it actually increases in size relative to the output. Figure 5C shows an embodiment in this regard in which the input 23 with its area A1 relative to the output region 24 with its area A2 remains essentially the same, but its shape is changed. In particular, a square input region is provided in Figure 5C. By constantly reducing the height and simultaneously increasing the width, this results in an elongated, narrow transverse slot in the output region 24 which is approximately twice as wide as the input. Its height has, however, decreased by more than half.

[0146] The expansion nozzle therefore leads to a decreasing height / width ratio over the length of the expansion nozzle. For example, the width B can increase by a factor of 3, while the height H decreases by the same factor. However, other factors are also possible in this context, whereby the cross-sectional area of ​​the outlet region 24 also decreases compared to the inlet region 23. In the present example in Figure 5C, the height of the nozzle at the outlet decreases significantly more than the width increases. As a result, the overall area of ​​the outlet is smaller than the cross-sectional area at the inlet. Accordingly, in this exemplary embodiment, there is not only a transverse flow velocity and thus an expansion of the mass perpendicular to the forward direction, but also a longitudinal expansion.

[0147] Figures 5D and 5E show two further designs, this time with round and oval inlet cross-sections, respectively. While in Figure 5D this oval shape in the inlet region 23 is transformed into a rectangular shape with clear corners in the outlet 24, in Figure 5E the edges are rounded and thus retain at least roughly the same shape as in the inlet region 23. In this design, the areas of the inlet and the outlet are the same, so that only a transverse flow occurs here, but no or only a very slight longitudinal flow. Accordingly, the mass is deformed primarily transversely to the direction of propulsion. In Figure 5E the areas are again different, so that here too, in addition to a transverse stretching of the mass, a longitudinal stretching is also generated.

[0148] In all of these arrangements, a decrease or change occurs along a first direction (e.g. width of the nozzle) perpendicular to the direction of advance and differently along a second direction perpendicular to the direction of advance (e.g. height H). Accordingly, the unequal decrease in the two different spatial directions not only causes a longitudinal expansion, i.e. along the length of the expansion nozzle, but also a transverse expansion, i.e. along the width B or the height H. The transverse expansions are in turn different due to the different heights and widths. This design makes it possible to bring about a longitudinal as well as a transverse expansion in a highly viscous mass in a targeted manner, the intensity of which is controlled by the geometry of the expansion nozzle.

[0149] Figure 7 shows a simulation illustrating the generation of transverse extensional flows by changing the nozzle geometry. The image shows a quarter of the nozzle, which is sufficient for the simulation due to symmetry reasons. The propulsion direction of the highly viscous mass is in the Y direction. Lighter colors indicate a higher flow velocity. The nozzle inlet can be seen in the upper corner; the flow velocity there is essentially the same. The nozzle inlet geometry defines the entire mass flow.

[0150] It can now be seen that the nozzle widens in the x-direction in the direction of advance, but at the same time becomes thinner, i.e. the dimensions in the z-direction decrease. Put simply, the nozzle becomes wider but also thinner in the direction of advance. This transition does not occur over the entire length of the nozzle, but in a very short section, which corresponds to about half or a third of the length of the nozzle. The ratio of the maximum width in the x-direction to the length of the nozzle, i.e. W / L, is approximately 2, i.e. the nozzle is significantly wider than it is long.

[0151] As can be seen, the flow velocity increases significantly, especially at the edge, due to the enlargement and decrease in the height of the nozzle. Therefore, a tensile stress is exerted on the viscous mass that is essentially perpendicular to the propulsion in the Y direction. This is referred to as a transverse tensile stress. However, the mass does not adhere to the wall, but rather slides off it. The simulation shows that hardly any shear forces occur that could lead to separation.

[0152] This transverse tensile stress leads to fiber formation in the highly viscous mass, the orientation of which is perpendicular to the forward direction. At about halfway along its entire length, the nozzle has reached its final height (in the Z direction) and width, so that no further transverse tensile stresses are generated, but rather uniform propulsion takes place. When the mass, deformed in this way, emerges from the nozzle, it can be cut along the fibers using mechanical measures to produce pieces of the same width and, depending on the propulsion speed, of different lengths. It is also possible to insert an extension nozzle after the transverse nozzle, which can be used for cooling or to build up pressure. This allows the temperature and pressure of the mass flow to be better controlled.

[0153] The nozzles shown here can be combined as desired with regard to their individual sections, geometries, and wall coatings to control fiber formation and prepare the desired end product. Particular attention should be paid to a highly viscous mass, so that sliding occurs primarily on the side walls.

[0154] Figures 6A and 6B show examples of the steps in a process for producing a texturate according to the proposed principle, as can be produced using the extruder arrangement and expansion nozzles shown in the figures. The process takes advantage of the fact that a dough mix with a lower water content leads to increased interaction between the individual proteins and polymers during kneading of the dough in the extruder arrangement, so that the resulting dough has a significantly increased viscosity. The viscoelasticity can be adjusted by adding sugar and salt, as well as by suitable thermomechanical treatment using the proposed extruder arrangement (e.g. the use of a two-axis screw drive).With the presented geometries of the stretching nozzle, a defined and prolonged / continuous stretch is applied to an extrudate with specific high-viscosity behavior - which leads to a very efficient stretching of a multi-phase extrudate. Shear is reduced due to the geometry and the low static friction due to the coating of the nozzle (depending on the geometry), so that breakage of the extrudate during propulsion or even wall slippage is largely avoided. With some protein mixtures, strong stretching can also be destructive and lead to fragmentation of the formed fibers if they are subjected to overstretching. Since the stretching stress depends mainly on the change in the velocity of the mass flow, the intensity and duration of the stretching can be easily adjusted using geometry factors, making this process very flexible for different protein sources.

[0155] Figure 6A shows a first embodiment of the proposed method. In step S1, a protein mixture is provided. This comprises a protein isolate from wheat and a protein isolate from pea protein. The proportion of proteins in the respective isolates is approximately 90% by weight, with a residual moisture content in the range of approximately 5% by weight and other components. In this embodiment, vegetable fibers are hardly present in the isolates. The two isolates are mixed in approximately equal proportions and make up approximately 55% by weight of the basic mixture. Likewise, 10% by weight of vegetable oil is added to the mixture, as well as salt in the range of 1% by weight and sugar in the range of 5% by weight, based on the basic mixture. Flavorings and spices are in the range of 2% by weight. The solid and oily components therefore make up 73% by weight, with the residual moisture in this mixture being approx.2.7% by weight (55% * 0.05%).

[0156] In step S2, water is added to the mixture in a concentration of approximately 27% by weight and mixed to form a light dough. This results in approximately 30% water by weight in the resulting dough.

[0157] The dough is then kneaded into a dough in step S3 under pressure and with an increase in temperature. The dough is kneaded in sections and then advanced slightly. In each section, the temperature is quickly increased from room temperature to over 100 °C and then kept in the range of 130 °C for the remaining kneading and advancement steps. The pressure here is over 5 to 6 bar. The mass is transferred directly into an expansion die in the discharge zone of the mixing extruder. The expansion die comprises a short inlet section in which the cross-section remains essentially the same, an elongated expansion section and an outlet section.

[0158] In this embodiment, in step S4 the mass is subjected to longitudinal expansion at a temperature of approximately 125°C, the stress of which results from a continuous reduction of the inlet cross-section to the outlet cross-section. The area of ​​the inlet cross-section is 8 times larger than the outlet cross-section. The expansion takes place over a distance which is 3 to 4 times larger than the diameter of the inlet cross-section. Therefore, due to the constant mass flow, the flow velocity over this distance also changes by a factor of 8, as a result of which the extrudate is stretched primarily in its length. In the middle section of the expansion nozzle, the static friction is reduced by a suitable coating, so that the extruded extrudate does not get stuck and no major shear forces occur which could lead to wall slippage or breakage of the extrudate.

[0159] The temperature does not change significantly during the expansion deformation, i.e., the texturate at the end of the expansion die has a temperature of approximately 125 °C. At the outlet, rapid expansion occurs due to the pressure drop. This creates a porous structure in the texturate without destroying the long-fiber structure produced by the expansion stress.

[0160] Another example of a method for producing a textured article having a fibrous structure whose length may be greater than 10 cm is shown in Figure 6B .

[0161] In step S1, a protein mixture is also prepared. In the example, this comprises a protein concentrate made from pea protein. The pure protein content in the concentrate is around 55% by weight. The remaining 45% by weight in the concentrate is divided into a residual moisture content of 15% by weight, vegetable oils and fats at approximately 10% by weight, and starch in the range of 10% by weight. The remaining 10% by weight are fibers and other residual vegetable components, such as salts and minerals.

[0162] For the base mix, the protein concentrate is mixed at a weight ratio of 75% with water at 25%. No other components are added in this example. This results in the following proportions for the base mix: 41% pure protein, 36% water, 7.5% oils and fats, 7.5% starch, and approximately 7.5% fiber.

[0163] In step S2', this essentially dry mixture is fed into a mixing extruder and the water is slowly added in successive stages under pressure and at an increased temperature. In other words, the water is not added all at once, but in several parts during the kneading process. The water is heated during addition so that there is little or no temperature drop and the dough is kept at a high or increasing temperature during the kneading process. The maximum temperature during the kneading process is in the region of approximately 145°C.

[0164] In step S3, the extrudate is subjected to tensile stress. The extrudate is propelled forward in sections without tensile stress and then stretched in sections. The latter occurs when the flow velocity of the extrudate is increased at the same mass flow rate. The stretching deformation in sections and the rest sections reduce transverse stresses or distortions in the extrudate, so that particularly long fibers are formed. The length of the propulsion, in which the flow velocity is increased in sections, is significantly greater than the diameter of the inlet cross section. Furthermore, in this design the increase in flow velocity in the tapered sections of the stretching nozzle is different. In particular, the flow velocity is only increased slightly at the beginning, but increases further during the propulsion. This prevents the fiber formation from breaking.In section S4, the product is suddenly depressurized at the exit. At the same time, the temperature drops slowly, not suddenly, to below 100 °C. This causes some of the water bound in the texturate to evaporate, leading to pore formation. The texturate thus produced is further processed in subsequent processes in step S4.

[0165] In a further alternative example not shown in the figures, a protein mixture is produced from a field bean concentrate and a wheat protein isolate by mixing them in proportions of 70% by weight to 30% by weight. The field bean concentrate contains, in addition to a protein content of 45% by weight, starch and sugar at 25% by weight, residual moisture of 10% by weight and fibers, oils and other components amounting to 20% by weight. The wheat protein isolate has a protein content of 93%, 3% by weight is residual moisture, 2% by weight starch and the rest oils and fats. The mixture given above results in protein contents in the range of 59% by weight, 4% by weight sugar and starch in the range of 18% by weight, a residual moisture of 8% by weight and 15% by weight remaining components.

[0166] This mass can then be mixed with water, for example, to create the base mixture, with 20% water being added to the 80% by weight of this mixture. This results in a total of 47.5% by weight of proteins and 26.4% by weight of water. The remainder, 14% by weight, is made up of starch and sugar, along with the other components. This base mixture is further processed according to the proposed method.

[0167] The processes described here produce a texturate whose moisture content is lower than the water content in the base mix during kneading of the dough. This is due to the water loss during expansion at the outlet of the expansion die after or during the stretch-forming step, especially if the temperature of the extrudate and the pressure are maintained above the vapor pressure of the water at that temperature. LIST OF REFERENCE SYMBOLS

[0168] 1 extruder arrangement

[0169] 10 worm gears

[0170] 11a, 11b Extruder section

[0171] 11c, l ld extruder section

[0172] 12a, 12b Screw section

[0173] 12 c screw section

[0174] 14 Inlet mixer

[0175] 15 Water inlet

[0176] 13 Ejection zone

[0177] 20 expansion nozzle

[0178] 21 nozzle body

[0179] 22 expansion section

[0180] 23 Nozzle inlet

[0181] 24 nozzle outlet

[0182] 25a, 25b expansion section

[0183] 25 c, 25d advance section

[0184] 25e advance section

[0185] 26 expansion section

[0186] 30 , 31 body

[0187] Ri , R2 final cross-section

[0188] Rs , R4 internal cross section

[0189] L length

[0190] S mass flow

Claims

PATENT CLAIMS 1. A method for producing a texture, comprising the steps: Providing a protein mixture which comprises at least a first protein mixture, in particular a legume protein mixture or a wheat protein mixture, with a weight proportion of between 40% by weight and 90% by weight based on a base mixture; Adding water in a proportion of between 10% and 50% by weight based on the basic mixture to form a dough; Extruding the dough to a maximum temperature between 110°C and 160°C to form a highly viscous mass; Stretching of the highly viscous mass at a temperature greater than 100°C by propelling the highly viscous mass through a stretching nozzle whose geometry changes over its length in such a way that a longitudinal and / or transverse stretching stress is generated on the mass.

2. The method according to claim 1, wherein the water is added to the protein mixture in an extruder; and / or a gas generating agent, in particular in solid form, is added to the base mixture, in particular comprising sodium bicarbonate, before adding water.

3. A method according to any one of the preceding claims, wherein the extruding step comprises a step of kneading the supplied protein mixture and water at an increasing temperature up to the maximum material temperature; and / or comprises adding gas during kneading of the supplied protein mixture and water.

4. Method according to one of the preceding claims, wherein the maximum material temperature is in the range from 110°C to 160°C and in particular between 115°C and 135°C and in particular between 120°C and 145°C.

5. A method according to any one of the preceding claims, wherein the step of extruding the dough is carried out at a pressure of 5 bar to 150 bar. 6 . Method according to one of the preceding claims, wherein a temperature of the texturate at the outlet of the nozzle is greater than 100 ° C.

7. Method according to one of the preceding claims, wherein in the step of stretching the flow velocity is increased at least in one direction and / or during the stretching the extrudate is stretched longitudinally and optionally also transversely and is simultaneously propelled forward. 8 . Method according to one of the preceding claims, in which the step of stretching comprises: stretching sectionally at temperatures greater than 100 ° C, in particular by driving the extrudate forward, so that a flow velocity is increased; and / or Propelling the extrudate at a substantially constant flow velocity, wherein a time at a substantially constant flow velocity is greater than a time during which the flow velocity is increased; and / or propelling the extrudate in which forces of different magnitude are exerted on the mass during propulsion, each perpendicular to the direction of propulsion; and / or in which the extrudate is stretched more along a first direction perpendicular to the direction of propulsion than along a second direction perpendicular to the direction of propulsion and the first direction; and / or increasing an average flow velocity of the extrudate within the nozzle to at least twice the amount. 9 . Method according to one of the preceding claims, in which a Distance of the advance of the high-viscosity mass by at least factor 1 and especially by a factor of 3 to 7 larger than one from the maximum diameter of the inlet cross-section and the maximum screw diameter. 10 . Method according to one of the preceding claims, in which the shear stress is changed in at least two successive sections during the advance.

11. Method according to one of the preceding claims, further comprising: Cooling to a temperature below 100 ° C to form the texture after the stretch forming step .

12. Extruder arrangement, comprising: a mixing extruder, with an inlet zone for feeding a base mixture which contains at least a protein mixture and water, a mixing zone and an output zone; wherein the mixing extruder is designed to generate a temperature increase across the zones up to a maximum temperature of between 110 ° C and 160 ° C; an expansion nozzle connected to the output zone of the mixing extruder, which has a length, an inlet cross section and an outlet cross section, wherein the outlet cross section is shaped differently than the inlet cross section, so that a longitudinal or transverse expansion is generated on the mass; and the expansion nozzle is configured to bring about a temperature of the advanced, highly viscous mass of greater than 100 ° C at the output.

13. Extruder arrangement according to claim 12, wherein an inner side of the expansion nozzle is coated with a fluoropolymer, in particular Teflon; or an inner side of a first section of the expansion nozzle comprises a first material, and an inner side of a subsequent second section of the expansion nozzle comprises a second material different from the first material. 14 . Extruder arrangement according to one of claims 12 to 13, in which the maximum temperature in at least one of the zones is in the range between 110 ° C and 160 ° C and in particular between 115 ° C and 135 ° C and in particular between 120 ° C and 145 ° C.

15. Extruder arrangement according to one of claims 12 to 14, wherein the expansion nozzle is designed to maintain a temperature of the propelled material, in particular in the range between 110 ° C to 160 ° C and in particular between 115 ° C and 135 ° C and in particular between 120 ° C and 145 ° C 16. Extruder arrangement according to one of claims 12 to 15, wherein an area of ​​the inlet of the expansion nozzle is larger than an area of ​​the outlet cross-section.

17. Extruder arrangement according to one of claims 12 to 16, wherein the expansion nozzle has a continuous decrease in the inner diameter from the inlet cross-section to the outlet cross-section.

18. Extruder arrangement according to one of claims 12 to 17, wherein the expansion nozzle has at least one section in which a reduction in diameter along a first direction perpendicular to the advancing direction is greater than a reduction along a second direction perpendicular to the first direction and advancing direction; and / or the expansion nozzle has at least one section in which an increase in diameter occurs along a direction perpendicular to the advancing direction, wherein an area of ​​the inlet cross-section is greater than an area of ​​the outlet cross-section; the expansion nozzle has at least a first section with a constant cross-sectional area, at least one second section with a decreasing cross-sectional area and at least one third section with a constant cross-sectional area;and / or optionally a material of a section with a constant cross-sectional area is different from a material of a section with a decreasing cross-sectional area.; 19. Extruder arrangement according to claim 18, wherein the at least one first section has the inlet cross-section and the at least one third section has the outlet cross-section, wherein optionally a length of the at least one first and / or the at least one second section is greater than the diameter of the inlet cross-section or the outlet cross-section.

20. Extruder arrangement according to one of claims 12 to 19, wherein the output cross-section has the shape of a circular ring in plan view, wherein an inner part surrounded by the circular ring is formed with a body tapering in the direction of the input cross-section, in particular a cone.

21. Extruder arrangement according to one of claims 12 to 20, in which the outlet cross-section in plan view has a plurality of openings arranged around an inner part, in particular of the same cross-section, wherein the inner part has a body tapering towards the inlet cross-section.

22. Extruder arrangement according to claim 21, wherein the inner part is arranged with a central opening, the cross section of which is optionally different from the cross sections of the openings surrounding the inner part. 23 . Extruder arrangement according to one of claims 12 to 22, further comprising: a cooling element, in particular a cooling nozzle, which is connected to the outlet of the expansion nozzle and is configured to cool the expansion-deformed, highly viscous mass to below 100 ° C.

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