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 paste 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 10 2023 106 032 . 5 of 10 March 2023, the disclosure of which is hereby incorporated in full 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 exit) 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 process presented.

[0025] Definition of legume protein

[0026] A legume protein is a protein mixture obtained from legumes. These include peas and broad beans, but also 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. Definition of non-legume protein

[0027] 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, pumpkin seeds, corn, rapeseed, and sunflower. Proteins from algae, yeast, fungal mycelium, and / or fungal fruiting bodies also fall under the category of non-pulse proteins.

[0028] 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.

[0029] Definition of concentrate and isolate

[0030] 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.

[0031] A plant protein isolate, for example, is a mixture of a plant protein in which the concentration of the plant 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 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, is sometimes referred to as concentrate or isolate.

[0032] 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.

[0033] Definition of other ingredients

[0034] In some aspects, additional functionality in protein composition, taste, textural composition, visual or haptic properties can be created by at least one further 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 also 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.

[0035] In addition, other ingredients such as salt, spices, but also additional starch, sugar, syrup, fats or oils may be present. These can be added either as part of the raw mass at the beginning or alternatively or additionally during the 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 lead to an adjustment in taste but also to a change in texture. These additional ingredients can be present in free form, but can also be bound in corresponding raw materials in a highly concentrated form, e.g. sugar in syrup

[0036] Another possibility is the addition of functional ingredients, such as flavors, and / or additional special protein or amino acid sources to adjust certain 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. Definition of basic mixture

[0037] 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, which is 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.

[0038] 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.

[0039] 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 varying amounts in the protein mix.

[0040] 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, due to the residual moisture in the protein mixture, is usually somewhat higher in the dough than the water added alone. However, in the finished textured product, it may be lower because some of the water has evaporated.

[0041] Definition of extrudate

[0042] In the following, the dough mass processed in an extruder by kneading or other mechanical processing at the extruder outlet, especially at the end of the screw section, is referred to as the extrudate or viscoelastic mass. The associated process is called extrusion. The texturate then corresponds to the finished, stretch-formed and otherwise processed extrudate.

[0043] Definition of fiber

[0044] 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.

[0045] 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.

[0046] Definition of thermomechanical treatment

[0047] 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.

[0048] Definition of axial and transverse strain

[0049] 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.

[0050] Definition of material temperature

[0051] 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.

[0052] 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.

[0053] By adjusting the viscoelasticity, for example, through a suitable selection of ingredients and 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 wider 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.

[0054] The proposed process is based on a combination of a base mixture of one or more protein mixtures as well as secondary components and water, which is extruded at a dry to medium moisture content (10% by weight to approx. 40% by weight) and at quite high material temperatures. To produce the texturate, a specially shaped die is used, in particular without cooling, to generate a strain deformation that leads to the fiber formation according to the invention. By applying strain-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 allows the contribution of shear stresses to be adjusted, 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.

[0055] This reduces the risk of flow instabilities in the die and enables very well-defined deformation through transverse and / or longitudinal stretching of the extrudate. This allows both transverse and longitudinal tensile stresses to be generated, primarily through the die geometry. Longitudinal tensile stress refers to a tensile stress that is essentially parallel to the extrusion direction. Transverse strain is a strain that is primarily perpendicular or transverse to the extrusion direction of the extrudate.

[0056] In addition, during this process the temperature is in some aspects above 100 ° C and the pressure inside the die is also more than 5 bar. The resulting texturate 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 even 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. At the outlet of the expansion die a directly expanded texturate is formed which can be used after rehydration or after rolling to collapse the pores and produce compact fibrous end products.

[0057] 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.

[0058] 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.

[0059] The type of tensile stress, i.e., transverse and / or longitudinal stress, can be determined by the nozzle geometry. The extent of the tensile stress, both transverse and longitudinal, 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.

[0060] 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 45% by weight and 75% 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 and 75% 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.

[0061] 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% by weight and 35% by weight based on the base mixture. Other possible proportions are 10% by weight, 15% by weight, 20% by weight, 25% by weight, 30% by weight, 45% by weight and 50% by weight and, above all, the respective ranges between two of these values, e.g. between 10% by weight 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.

[0062] Possible proteins include one or a combination of the aforementioned legume proteins, including soy. Mixtures of one or more legume proteins and another protein mixture, particularly a non-legume protein mixture, can also be used. These mixtures are also available as concentrates or isolates, so the pure protein content in the texturate is usually somewhat lower.

[0063] In the process, water is added to the protein mixture in a proportion of between 20% and 50% by weight, based on the base 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 can also 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.

[0064] 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.

[0065] 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.

[0066] The extrudate produced in this way (also referred to as a highly viscous but at the same time highly elastic matrix) is then strain-deformed at a temperature of greater than 90 °C and in particular more than 100 °C. This takes place by propelling the hot, highly viscous mass, whereby at the same time a strain-deformation is exerted on the mass which is transverse, i.e. essentially perpendicular to the direction of advance. This can be generated, for example, by a special strain-deformation nozzle which does not need to be cooled separately. According to the proposed principle, the strain-deformation mentioned above takes place in a transverse direction, i.e. perpendicular to the advance. This is therefore also referred to as transverse strain, although transverse strain can occur in two directions. In addition, longitudinal strain, i.e. strain in the direction of advance, can also occur. However, this is usually less than the strain in the transverse direction.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. In some aspects, the strains are achieved, among other things, by the extrudate sliding along an inner wall, so that little or no shear flow occurs. It is particularly important to emphasize here that the viscosity of the highly viscous mass should not be too low, as otherwise the required strains cannot be generated.

[0067] In this way, the continued elevated temperature, particularly above the evaporation temperature of water, and the existing pressure result in continuous extensional deformation and the resulting extensional stresses creating long, connected fibers, e.g. up to 30 cm, which resemble a meat structure. The extensionally deformed extrudate leaves the die as a texturate, with a sudden drop in temperature and pressure 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.

[0068] 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. In some aspects, the temperature and pressure increase occur continuously, but can also occur in sections, i.e. with sections of the process in 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 made up of the components of the base 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 kept constant. In some aspects, the temperature increase is designed so that the maximum temperature is reached approximately halfway through the extruder section. Likewise, the temperature can be changed several times during the extrusion process, so that different temperatures are set in different sections.

[0070] Likewise, during kneading and extrusion, the pressure rises to a maximum value. Accordingly, some aspects envisage extrusion at a pressure ranging from 1 bar to 100 bar or higher. Typical ranges are between 20 bar and 80 bar, and in particular, less than 60 bar at the end of the extruder.

[0071] By varying the thermal stress profile during extrusion, the degree of protein-protein interactions and polymerization reactions can be varied, allowing for further adjustment of elasticity and viscosity. This aspect is achieved not only in the extruder itself (i.e., during kneading of the dough), but also, to a lesser extent, during the stretching deformation.

[0072] In some further aspects, a gas is added during kneading, i.e. in the screw section of the extruder, in order to loosen the dough and also the subsequent extrudate. The gas can be added in the screw section of the extruder at one point, for example in the initial area of ​​the extruder, but also at various 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 material of the extrudate and remains bound in the material. Only during the later stretching deformation and particularly at the end when the texturate is exited does the pressure decrease again, so that the gas contributes to loosening the extrudate. The gas used for this purpose can be carbon dioxide, nitrogen and in some cases even air.

[0073] In some cases, a gas-generating material can be added to the dough. This material decomposes during further processing, particularly during kneading in the extruder, and thus contributes to gas formation. A typical material of this type is baking soda (sodium bicarbonate), which decomposes with citrates or other mild acids to form carbon dioxide. In some aspects, both substances are initially added to the basic mix 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 aspects, only baking soda is added, and during kneading, due to the high temperature, it decomposes back into carbon dioxide and sodium carbonate.

[0074] In the proposed method, the expansion die is not actively cooled in some aspects, i.e., the expansion-formed textured material leaves the expansion die at a temperature above 100 °C. Likewise, the expansion forming may be performed at different temperatures, so that in some aspects the expansion forming is divided into several steps, of which individual steps are performed at different temperatures above 100 °C.

[0075] During strain deformation, the flow velocity increases, but the mass flow remains essentially the same. With longitudinal strain, the flow velocity changes along the direction of advance, while with transverse strain it changes perpendicular to this, i.e. the viscous mass is stretched in a direction transverse to the direction of advance. Since there are two transverse directions, it can be provided that during the application of strain stress, a flow velocity is increased in a first direction transverse to the direction of advance, while it remains the same or decreases in a second direction. In this way, the mass flow can be kept constant.

[0076] Accordingly, in some aspects, during the application of a tensile stress, the high-viscosity mass is stretched more along a first direction perpendicular to the advance direction than along the advance direction and a second direction perpendicular to the advance direction and the first direction.

[0077] This elongation 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.

[0078] It is also possible that a propulsion velocity is, at least in part, lower than a flow velocity in a direction perpendicular to the propulsion direction. This means, for example, that in some sections the mass is widened faster than it is propelled.

[0079] 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, also laminar. To avoid rupture of the expansion stresses, it is advisable to keep the static friction between the mass and the wall low so that the mass slides along it. By driving the extrudate forward, the mass is stretched at temperatures above 100 °C and in particular between 105 °C and 115 °C. At the end of this stretching, the temperature of the intermediate product is in some aspects still above 100 °C, for example in the range between 110 °C and 135 °C. In special aspects it can even be above 130 °C. The longitudinal or transverse stretching can take place continuously or in sections.In the first case, for example, this is achieved by a continuous decrease in the cross-sectional area. In some aspects, instead of the cross-section, a ratio of width to height of the inlet and outlet is used, with the ratio also changing. In particular, one of the two sizes decreases between the inlet and outlet. Thus, transverse flows and expansions can be deliberately generated in this way.

[0080] 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, the 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.

[0081] In some aspects, the transverse extension stress is generated by the extension nozzle in that its entrance has an entrance area that is larger than an exit area of ​​an exit of the extension nozzle. Extension stress can also be generated by an extension nozzle that has a maximum entrance width and a maximum exit width, each in a first direction, and a maximum entrance height and a maximum exit width in a second direction perpendicular thereto, wherein a maximum exit width in the first direction is greater than the maximum entrance width in the first direction and the maximum entrance width in the second direction is smaller than the maximum exit width in the second direction.It is possible in some aspects that a distance of propulsion of the high-viscosity mass in which a tensile stress is exerted on the high-viscosity mass substantially perpendicular to a propulsion direction is less than or equal to a maximum distance along which the high-viscosity mass is strain-deformed.

[0082] 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.

[0083] Due to the low water content in the dough, the viscosity is higher than that of extrudates with a higher water content. The increased viscosity leads to greater tensile stresses due to the differences between the inlet and outlet cross-sections. The length of the die can also play a role. This is helpful for the aspects presented here, as it allows the shape, length, and design of the die to influence the mass flow velocity.

[0084] In some aspects, a length of the nozzle through which the viscous mass is propelled, along which a maximum distance between two opposite regions of the expansion nozzle changes, lies between 0.5 times and 2.5 times this maximum distance. To generate transverse expansion deformations of the viscous mass, for example, the length in a first direction, perpendicular to the length of the nozzle, is changed over the length of the nozzle, e.g. 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 output cross-section is reduced compared to the input cross-section, longitudinal expansions are also caused in addition to transverse expansions.

[0085] 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.

[0086] In some aspects, after strain deformation, the texturate is cooled to a temperature below 100 °C. This can be achieved by flash relaxation, i.e., by releasing the pressure while cooling. Cooling may also begin later than the pressure release. The sudden pressure release at a temperature close to 100 °C, such as between 105 °C and 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.

[0087] 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. Likewise or alternatively, additional sugar can be added, i.e. sugar beyond that 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 so reduce network formation. Possible sugars for this would be glucose, fructose, maltose, syrup, sugary fruit juices and others.Salt can be added up to 1.5% by weight of the basic mixture, colouring ingredients and flavourings up to 2% by weight each.

[0088] With the combination of additional wheat protein, 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.

[0089] 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.

[0090] Some further aspects relate to an extruder arrangement suitable for carrying out the method.

[0091] 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 ejection 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 ejection zone of the mixing extruder and is configured to expand a high-viscosity mass driven through it perpendicular to a direction of advance during advance, in particular in a sliding manner, and to bring about a temperature of the driven high-viscosity mass of greater than 100 °C at the outlet.

[0092] Thus, in the extruder arrangement according to the invention, the highly viscous mass is subjected to a transverse or longitudinal extension deformation with, at the same time, relatively little or no shear stress, so that in plant-based extrudates, a targeted and in particular longitudinal or transverse fiber formation of up to 30 cm begins.

[0093] 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.

[0094] 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 is different from the first material. In a further embodiment, it is provided that sections of the expansion nozzle have different static friction.

[0095] In contrast to metals, plastics have significantly lower heat transfer. Accordingly, in some aspects, in sections where the surface is coated 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 so that the temperature of the extruded material remains essentially constant in these sections. The temperature maintained 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.

[0096] 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.

[0097] Some aspects concern the shape of the inlet cross-section of the expansion nozzle and the outlet cross-section of the nozzle. In some aspects, the expansion nozzle is directly connected to the extruder's discharge zone, with their cross-sections being identical. However, it is possible to couple the extruder and expansion nozzle via a short coupling piece, provided the coupling piece 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, each 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 height in the second direction is smaller than the maximum outlet height in the second direction. In other words, an inlet has a smaller width than the outlet. In contrast, the height of the inlet is greater than the height of the outlet. Thus, the width of the nozzle increases over the length of the nozzle, while the height decreases.

[0098] In some embodiments, the expansion nozzle has a continuous decrease or reduction of the area of ​​the inlet cross-section to the outlet cross-section, or a continuous decrease of the ratio between the inlet ratio H ElnG an g / B Elngan g and the initial ratio H Aus _ g an g / B Ausgan g . 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 at the same time, so that in this way primarily transverse expansion stresses are built up . Here, too, there can be widenings in some sections, so that the nozzle has sections with a constant cross-sectional area or height .

[0099] The length of the nozzle can in some cases be designed such that the length lies in the range between one time and three times the greatest width or height. In particular, in some aspects the nozzle has a first section whose length along the direction of advance is between 0.5 times and 2.5 times the maximum width of the expansion nozzle. However, the nozzle and also the method are in some aspects designed such that the nozzle geometry does not lead to a sudden pressure drop, i.e. the volume of the nozzle does not suddenly increase over its length, so that the mass can expand. This prevents breakage.

[0100] In some aspects, it is further provided that the at least one first section has the input cross-sectional area or the input cross-section and the at least one third section has the output cross-sectional area or the output cross-section, wherein optionally a length of the at least one first and / or the at least one second section is greater than a maximum extent of the input cross-section in one direction or of the output cross-section. In this context, there may also be a plurality of second sections, which in turn can be designed differently, i.e. with constant or decreasing sections.

[0101] 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.

[0102] 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.

[0103] In this context, for the above-mentioned embodiment, the inner part can be arranged with a central opening, the cross-section of which is optionally different from the cross-sections of the openings surrounding the inner part.

[0104] Finally, in some aspects, a cooling nozzle or cooling tube may also be provided, which is connected to the outlet of the expansion nozzle and is configured to cool the expansion-deformed textured material to below 100 ° C.

[0105] Further advantages of the process and arrangement presented here include the ability to adjust the stretching tension 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0106] 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.

[0107] Figure 1 shows a mixing extruder as it can be used for the proposed process and the extruder arrangement according to the proposed principle;

[0108] Figure 2A shows a first embodiment of an expansion nozzle in cross-sectional view according to the proposed principle;

[0109] Figure 2B shows a section of a simulation to represent transverse strain stresses according to the proposed principle;

[0110] Figures 3A and 3B show two further designs of expansion nozzles according to the proposed principle;

[0111] Figures 4A and 4B show two further designs of expansion nozzles according to the proposed principle in cross-sectional view;

[0112] Figures 5A and 5B1 and 5B2 are each an embodiment of a nozzle for generating a transverse tensile stress and a corresponding simulation;

[0113] Figures 6A and 6B show two further embodiments of nozzles with different cross-sections according to some aspects of the proposed principle;

[0114] Figure 7A shows a further embodiment of a nozzle according to the proposed principle;

[0115] Figures 7B and 7C are simulations without and with adhesion of the embodiment shown in Figure 7A to illustrate some aspects;

[0116] Figure 8 shows another expansion nozzle according to the proposed principle.

[0117] REVISED SHEET (RULE 91) ISA / EP Figures 9A and 9B are two embodiments of processes for producing a textured article according to the proposed principle.

[0118] DETAILED DESCRIPTION

[0119] 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.

[0120] 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.

[0121] Figure 1 shows part of an extruder assembly according to the proposed principle. The extruder assembly is designed with a mixing extruder 1 with a twin worm gear, in which the supplied mass is kneaded by means of two worm gears and driven forward toward 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 several sections 11a, 11b, 11c, 11d, and 11e of the mixing extruder.

[0122] The respective sections are mechanically sealed to one another via flanges or other means. In this way, the mixing extruder shown can be either lengthened by adding individual sections or shortened by removing them. The screw sections 12a, 12b, and 12c are designed in a similar manner, so that they too can be lengthened or shortened by adding or removing individual screw elements.

[0123] 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.

[0124] 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.

[0125] 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 10 and 80 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 applied at one or more points during kneading to ensure an even distribution of the gas throughout the dough.

[0126] 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.

[0127] 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 subjected to elongation deformation by a uniform propulsion.

[0128] Figure 2A 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 also of the outlet region 24 can be shaped differently, for example as shown in Figure 2A, either completely circular, but also round-ended or oval-shaped.

[0129] REVISED SHEET (RULE 91) ISA / EP 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 pitch 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.

[0130] 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.

[0131] To achieve a constant mass flow, this means that the flow velocity depends on the radius of the inlet and outlet areas, or rather on their respective areas. For example, if the inlet area has an area three times larger than the area of ​​the outlet area, the flow velocity in the outlet area must also be increased by a factor of three to ensure the same mass flow.

[0132] Due to the increasing flow velocity, the extruded dough mass is stretched parallel to the direction of expansion. As a result, elongated fiber structures form at the continued high pressure of over 7 bar and the high temperature in the expansion nozzle in the range of over 100 °C. The uniform tapering, 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 could lead to tearing of the extruded mass.

[0133] In another aspect, the coating of the inside of the expansion nozzle can also be provided with a particularly 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 is particularly low-friction, so that the dough being pushed forward 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.

[0134] Figure 2B shows a simulation illustrating the generation of longitudinal extensional flows by continuously decreasing the cross-section along the length of the nozzle. The diagram shows only a cross-section because the nozzle is rotationally symmetric.

[0135] The propulsion direction of the highly viscous mass is the positive Z direction. Lighter colors indicate a higher flow velocity. The round inlet of the nozzle can be seen in the top corner; the flow velocity there essentially corresponds to the propulsion through the mixing extruder. The inlet geometry of the nozzle defines the overall mass flow, which is the same across all nozzle geometries of the type presented here for reasons of simplicity. The background to this is that a lower mass flow in sections of the nozzle would lead to an expansion of the mass due to the pressure in the nozzle. However, such an expansion carries the risk of destroying the fibers or lowering the vapor pressure of the water present in the mass below the boiling vapor pressure, causing it to condense. Overall, with the present geometries and the proposed principle (although not necessarily excluded), an expansion in the nozzle should not occur.This means that each surface or volume section in the direction of advance must be either the same size or smaller than a previous surface or volume section.

[0136] It can now be seen that the nozzle continuously shrinks in the direction of propulsion, i.e., its cross-section continuously decreases. This results in a continuous increase in the flow velocity of the viscous mass along the length of the nozzle. The low static friction also causes the highly viscous mass to slide along the inner wall of the nozzle, so that, with cross-sections that are not too large, a uniform longitudinal expansion, i.e., an expansion in the direction of propulsion, occurs.

[0137] 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.

[0138] 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 R2 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.

[0139] 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 R4 is reduced to a smaller area of ​​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.

[0140] 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.

[0141] 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 rather only by twice as much, for example. 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 R2, and the flow velocity increases again slightly while the mass flow remains the same.

[0142] On the outlet side, a further rest section 25e of the expansion nozzle 20 is arranged, in which the extruded, stretch-formed material is extruded again. Section 25e forms the end section, at whose outlet 24 the mass exits the nozzle.

[0143] 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 R4 to R3) and thus in its cross-sectional area. Accordingly, the flow velocity increases particularly strongly here, while it increases somewhat less in the following expansion sections (e.g. by a factor of 4 in the first expansion section, and then by twice as much 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.

[0144] 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.

[0145] 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.

[0146] 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 R3in 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.

[0147] 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 tensile stress occurs.

[0148] 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 subjected to greater extensional deformation without wall slippage occurring. Accordingly, shorter extension sections or extension 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 extension sections serve to relax the extruded extrudate somewhat and thus prevent the extrudate from tearing off and the production of shorter fibers.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] In both embodiments, a knife or a similar mechanical device can be arranged at the outlet of the expansion nozzle, which cuts open the circularly ejected textured material and transports it further along a conveyor belt.

[0157] The ring diameter in the outlet area 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.

[0158] Figures 5A to 8 address further aspects, namely that the inlet cross-section does not decrease uniformly (albeit in sections), but rather the inlet reduces in one preferred direction, while in the other direction it actually increases relative to the outlet. This forms an outlet that forms a slot, whereby the ratio of width to height and also the shape of the side surfaces can vary.

[0159] In this regard, Figure 5A shows an embodiment in which the input surface A1 is essentially the same as the output surface A2, but their respective shapes are changed. In particular, Figure 5A shows a square input region. By steadily decreasing the height and simultaneously widening the width, an elongated, narrow transverse slot results in the output region 24, which is approximately twice as wide as the input. Its height, however, has decreased by more than half.

[0160] The expansion nozzle therefore leads to a decreasing height / width ratio over the length of the expansion nozzle. For example, the width 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 which reduce the cross-sectional area of ​​the outlet region 24 compared to the inlet region 23. In the present example in Figure 5A, 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.

[0161] Figure 5B1 shows in the upper part a simulation of the occurring tensile stresses with adhesion and friction effects along the inside. The propulsion direction is now along the Y-axis, the Z-axis corresponds to the width B of the nozzle in part Figure 5A. Due to the friction, the speed at the edge increases only insignificantly over the length shown here, but a broadening of the speed profile in the width can be observed, since the height of the nozzle also decreases continuously in the X-direction. The maximum speed increase, however, occurs due to the friction rather in the middle of the

[0162] CORRECTED SHEET (RULE 91) ISA / EP width (since only half the nozzle is shown here, this must be added for reasons of symmetry).

[0163] The lower figure shows the simulation through the nozzle without friction on the inner walls. Here, a significant increase in velocity occurs at the edge, i.e., in the Z-direction, which causes the tensile stresses.

[0164] Figures 6A and 6B show two further designs, this time with round and oval input cross-sections, respectively. While in Figure 6A this oval shape is transformed in the input area 23 into a rectangular shape with clear corners in the output 24, in Figure 6B the edges are rounded and thus retain at least roughly the same shape as in the input area 23. In this design, the areas of the input and the output are the same, so that only a transverse strain occurs here, but no or only a very slight longitudinal strain. Accordingly, the mass is deformed primarily transversely to the direction of advance. In Figure 6B the areas are again different, so that here too, in addition to a transverse strain of the mass, a longitudinal strain is also generated.

[0165] In all of these arrangements, there is a decrease or change along a first direction (e.g. width of the nozzle) perpendicular to the direction of advance, which is different from 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 longitudinal expansion, i.e. along the length of the expansion nozzle, but also 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 longitudinal as well as transverse expansion in a highly viscous mass in a targeted manner, the intensity of which is controlled by the geometry of the expansion nozzle.

[0166] Figure 7A shows a further embodiment of such an arrangement, in which the expansion section does not run over the entire length of the nozzle, but only over a partial area, e.g. half of it. Adjoining this is a rest cut, which is longer than the embodiment in Figure 3A. In the embodiment, the inlet area 23 is quite short and designed only as a circular connecting piece. The outlet area 24 of the expansion nozzle is designed as a slot with straight side walls.

[0167] The short inlet section 25d of the expansion nozzle 20 in Figure 7A is followed by an expansion section 25b which tapers in height but at the same time widens. In this section, the outlet height R3in is approximately one third as large as the inlet height or the inlet diameter Ri. The first expansion section 25b is designed with a continuous widening and reduction in height in the direction of the outlet region 24 and has a length LI which is greater than the first rest section 25d in the inlet region of the expansion nozzle, but shorter than a second rest region 25c which adjoins the outlet of the first expansion section 25b. This second rest region 25c is exactly as long as the sum of the first rest section 25d and the first expansion section 25b and also forms the outlet region 24.

[0168] Figure 7B shows a simulation without effects such as adhesion and friction, illustrating the generation of transverse extensional flows by changing the nozzle geometry. The illustration shows one half of the nozzle, which is sufficient for the simulation for reasons of symmetry. The propulsion direction of the highly viscous mass is 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.

[0169] 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.

[0170] As can be seen, the widening and decreasing height of the nozzle cause the flow velocity in the X direction to increase significantly, especially at the edge. 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.

[0171] This transverse tensile stress leads to fiber formation in the extrudate, 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 a uniform propulsion takes place. When the stretch-deformed texturate emerges from the nozzle, it can be cut along the fiber by mechanical means 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.

[0172] The sliding is mainly caused by a combination of low static friction coefficient on the inside of the wall and the viscosity of the mass.

[0173] Figure 7C shows a similar simulation, but now with adhesion effects and friction. While the behavior towards the central region of the nozzle is similar to that in sub-Figure 7B, an overall lower flow velocity is shown here, which also has its maximum at a quarter of the width. This effect is due to the adhesion and friction at the edge. The extruded extrudate should therefore have as little adhesion or friction as possible on the wall of the nozzle in order to produce good tensile stress. This is achieved, among other things, by increasing the viscosity and using suitable materials such as Teflon or other coatings with a low coefficient of static friction. In the subsequent straight section, the conditions are constant again; further tensile stresses are unlikely to occur here, or only to a small extent.

[0174] It has been found that the sliding process leads to the desired result, while excessive adhesion of the extruded extrudate to the wall of the expansion die is rather negative for the required fiber formation.

[0175] Figure 8 shows a further embodiment of an expansion nozzle, which is constructed similarly to the embodiment in Figure 3B. The essential difference, however, lies in the different geometry. While the nozzle in Figure 3B deforms evenly over its length, the embodiment in Figure 8 has, on the one hand, a differently shaped inlet, namely a rectangle with rounded edges, and, on the other hand, the outlet, which is shaped like a slot. This does not result in a uniform taper in the two expansion sections 25b, but rather a widening of the width B in each case, with a simultaneous reduction in the height H. In this embodiment, there are also two longer rest sections, 25d and 25e, as well as a short rest section. Nevertheless, the length of the rest sections in this exemplary embodiment is shorter than the width B of the nozzle at the outlet 24.

[0176] In this exemplary embodiment, the expansion nozzles shown here in Figures 5 to 8 are characterized primarily by the fact that they increase in width while the height is greatly reduced, even though the total area between the inlet and outlet hardly reduces at all. As a result, the advance speed also remains essentially constant, so that only transverse expansion stresses occur, which lead to fiber formation in a direction transverse to the advance. In addition, it can have several shorter or longer expansion sections as well as rest sections in which the advanced dough is not stretched any further or is only stretched slightly. In addition, it is possible in some aspects for the expansion nozzle to comprise further heating or cooling elements in order to be able to generate different temperatures in the individual sections if necessary.

[0177] 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.

[0178] Figures 9A and 9B 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 expansion nozzle geometries presented, a defined and prolonged / continuous expansion is applied to an extrudate with specific, highly viscous behavior—leading to highly efficient expansion of a multiphase system. Shear is reduced due to the geometry and the low static friction provided by the nozzle coating (depending on the geometry), thus largely preventing extrudate breakage during propulsion or even wall slippage.

[0179] For some protein mixtures, strong stretching can also be destructive and lead to fragmentation of the fibers formed if they are subjected to overstretching. Since the stretching stress depends mainly on the change in the speed of the mass flow, the intensity and duration of the stretching can be easily adjusted using geometric factors, making this method very flexible for different protein sources. Figure 9A 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. Plant fibers are hardly present in the isolates in this embodiment.The two isolates are mixed in roughly equal proportions and make up about 55% by weight of the base mixture. 10% by weight of vegetable oil, as well as salt in the range of 1% by weight and sugar in the range of 5% by weight, are also added to the mixture. Flavorings and spices are each in the range of 2% by weight, based on the base mixture. Thus, the solid and oily components make up 73% by weight, with the residual moisture in this mixture amounting to approximately 2.7% by weight (55% * 0.05%).

[0180] 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 slurry.

[0181] The dough is then kneaded into a dough in step S3 under pressure and at an increased temperature. The dough is kneaded in sections and then slightly advanced. In each section, the temperature is rapidly increased from room temperature to over 100 °C, and then maintained at around 130 °C for the remaining kneading and advance steps. The pressure during this process is between 5 and 6 bar.

[0182] In the discharge zone of the mixing extruder, the mass is transferred directly into an expansion die. The expansion die comprises a short inlet section, in which the cross-section remains essentially constant, an elongated expansion section, and an outlet section.

[0183] 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 that could lead to wall slippage or breakage of the extrudate.

[0184] 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.

[0185] 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 9B.

[0186] 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 is fiber and other residual vegetable components, such as salts and minerals.

[0187] For the basic mix, the protein concentrate is mixed at a weight proportion of 75% with water at 25%. No other components are added in this example. This results in the following proportions for the basic mix: 41% by weight pure protein, 36% by weight water, 7.5% by weight oils and fats, 7.5% by weight starch and approx. 7.5% by weight fibers. In step S2', this essentially dry mix is ​​fed into a mixing extruder and the water is slowly added in various successive stages under pressure and with an increase in temperature. In other words, the water is not added all at once, but in several parts during the kneading process. The water is heated while it is being added, so that there is no or only a slight drop in temperature and the dough is kept at a high or increasing temperature during the dough process.The maximum temperature during the kneading process is in the range of approximately 145 ° C.

[0188] 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 in sections and the static sections reduce transverse stresses or distortions in the extrudate so that particularly long fibers are formed. The length of the propulsion, during 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.

[0189] In section S4, the product is suddenly released 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 produced in this way is further processed in subsequent processes in step S4.

[0190] In another alternative example not shown in the figures, a protein mixture is produced from a broad bean concentrate and a wheat protein isolate by mixing them in proportions of 70% to 30% by weight. The broad 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 totaling 20% ​​by weight. The wheat protein isolate has a protein content of 93%, 3% by weight is residual moisture, 2% by weight is starch, and the remainder is oils and fats.

[0191] The mixture specified above results in protein contents in the range of 59.4% by weight, sugar and starch in the range of 18% by weight, a residual moisture content of 8% by weight, and 15% by weight of other components.

[0192] 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 can be further processed using the proposed method.

[0193] The processes described here produce a texturate with a moisture content lower than the water content in the base mix during dough kneading. This is due to water loss during expansion at the exit of the expansion die after or during the stretch-forming step, particularly when the temperature of the extrudate and the pressure are maintained above the vapor pressure of the water at that temperature.

[0194] LIST OF REFERENCE SYMBOLS

[0195] 1 extruder arrangement

[0196] 10 worm gears

[0197] 11a, 11b Extruder section

[0198] 11c, l ld extruder section

[0199] 12a, 12b Screw section

[0200] 12 c screw section

[0201] 14 Inlet mixer

[0202] 15 Water inlet

[0203] Ejection zone

[0204] 20 expansion nozzle

[0205] 21 nozzle body

[0206] 22 expansion section

[0207] 23 Nozzle inlet

[0208] 24 nozzle outlet

[0209] 25a, 25b expansion section

[0210] 25 c, 25d advance section

[0211] 25e advance section

[0212] 26 Expansion section

[0213] 30 , 31 body

[0214] R4, R2Final cross-section

[0215] R3, R4Internal cross-section

[0216] L length

[0217] S mass flow

Claims

PATENT CLAIMS 1. A method for producing a texturate, comprising the steps of: providing a protein mixture which comprises at least a first protein mixture, in particular a legume protein mixture such as a pea protein mixture or a field bean protein mixture, with a weight proportion of between 45% by weight and 80% by weight based on a base mixture; Adding water in a proportion of between 20% and 45% by weight based on the basic mixture to form a dough; Extruding the dough at a maximum temperature between 110 ° C and 160 ° C to form an extrudate ; Exerting an extensional stress on the extrudate substantially perpendicular to a direction of advance at a temperature greater than 100 ° C during advance of the extrudate through an expansion die . 2 . A method according to any one of the preceding claims, wherein the step of extruding comprises a step - kneading the supplied protein mixture and water at an increasing temperature up to a maximum material temperature, wherein optionally the maximum material temperature is in the range of 110 ° C to 160 ° C and in particular between 115 ° C and 135 ° C and in particular between 120 ° C and 145 ° C; and / or - comprising adding gas during kneading of the supplied protein mixture and water; and / or wherein the step of providing a protein mixture to the base mixture comprises adding a gas generating agent to the base mixture, in particular in solid form, and in particular comprising sodium bicarbonate. 3 . Method according to one of the preceding claims, wherein the step of extruding the dough takes place at a pressure of 5 bar to 150 bar; and / or wherein a temperature of the texturate at the outlet of the nozzle is greater than 100 ° C. 4 . A method according to any one of the preceding claims, wherein during the application of an extension stress the extrudate slides substantially along an inner surface of the extension die. 5 . Method according to one of the preceding claims, in which, during the application of an extension stress, the extrudate is stretched more strongly along a first direction perpendicular to the direction of advance than along the direction of advance and a second direction perpendicular to the direction of advance and the first direction.

6. Method according to one of the preceding claims, wherein in the step of exerting a tensile stress, a flow velocity is increased in a first direction transverse to the direction of propulsion, while it remains the same or decreases in another second direction.

7. Method according to one of the preceding claims, wherein the step of applying a tensile stress generates a longitudinal tensile stress. 8 . Method according to one of the preceding claims, in which exerting a tensile stress comprises: sectionally transverse strain deformation at temperatures of greater than 100 ° C by advancing the extrudate so that a flow velocity in a direction perpendicular to the direction of advance is increased; and / or sectionally longitudinal strain deformation at temperatures of greater than 100 ° C by advancing the extrudate so that a flow velocity in a direction along the direction of advance is increased; and / or advancing the extrudate such that a propulsion velocity is at least partially lower than a flow velocity in a direction perpendicular to the direction of advance; and / or advancing 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; Propulsion of the extrudate, in which different forces are exerted on the mass during propulsion, each perpendicular to the direction of propulsion; and / or Increasing an average flow velocity of the extrudate within the nozzle to at least twice .

9. Method according to one of the preceding claims, in which an exertion of an extension stress is generated by the extension nozzle, the inlet of which has an inlet area which is larger than an outlet area of ​​an outlet of the extension nozzle.

10. Method according to one of the preceding claims, in which an exertion of an extension stress is generated by the extension nozzle, which has a maximum inlet width and a maximum outlet width in a first direction and a maximum inlet height and a maximum outlet width 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 smaller than the maximum outlet width in the second direction.

11. Method according to one of the preceding claims, in which a distance of advance of the extrudate in which a tensile stress is exerted on the extrudate substantially perpendicular to a direction of advance is less than or equal to a maximum distance along which the extrudate is strain-deformed. 12 . Method according to one of the preceding claims, in which a length along which a maximum distance between two opposite regions of the expansion nozzle changes lies between 0.5 times and 2.5 times this maximum distance. 13 . Method according to one of the preceding claims, in which the exertion of a tensile stress comprises at least two successive tensile stresses, in particular of different strengths, on the extrudate. 14 . 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.

15. An extruder arrangement comprising: a mixing extruder having an inlet zone for supplying a base mixture containing at least one protein mixture and water, a mixing zone, and an ejection zone; wherein the mixing extruder is configured to generate a temperature rise across the zones up to a maximum temperature of between 110°C and 160°C; an expansion nozzle connected to the outlet zone of the mixing extruder, which is configured to expand a highly viscous mass driven through it perpendicular to a direction of advance during advance, in particular in a sliding manner, and to bring about a temperature of the driven highly viscous mass at the outlet of greater than 100°C.

16. Extruder arrangement according to claim 15, wherein an inner side of the expansion nozzle is coated with a fluoropolymer, in particular Teflon, or a ceramic or glass; and / or wherein the expansion nozzle is designed such that the highly viscous mass slides substantially along an inner surface of the expansion nozzle; 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.

17. Extruder arrangement according to one of claims 15 to 16, wherein the expansion nozzle is designed to maintain a temperature of the extruded 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.

18. Extruder arrangement according to one of claims 15 to 17, wherein the expansion nozzle has a continuous decrease of an area of ​​the inlet cross-section to an area of ​​the outlet cross-section.

19. Extruder arrangement according to one of claims 15 to 18, in which 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 width 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 smaller than the maximum outlet width in the second direction.

20. Extruder arrangement according to one of claims 15 to 19, in which the expansion nozzle has a first section whose length along the direction of advance is between 0.5 times and 2.5 times the maximum width of the expansion nozzle.

21. Extruder arrangement according to one of claims 15 to 20, in which the expansion nozzle has a first section with a changing geometry and a second section connected thereto with a substantially constant geometry.

22. Extruder arrangement according to one of claims 15 to 21, wherein the output cross-section in plan view has the shape of a slot with optionally rounded short side surfaces.

23. Extruder assembly according to one of claims 15 to 22, further comprising: a cooling nozzle connected to the outlet of the expansion nozzle and configured to cool the texturate to below 100°C.

Images