EP4266897A1

EP4266897A1 - Foamed, elastic, protein-based product, method for producing such products, more particularly plant protein- and plant fibre-based extruded meat analogues, device for carrying out such a method and use of the product for producing plant protein-based meat analogues

Info

Publication number: EP4266897A1
Application number: EP21824478.8A
Authority: EP
Inventors: Erich Windhab; Joel Zink; Cédric SAX
Original assignee: Eidgenoessische Technische Hochschule Zurich ETHZ
Current assignee: Eidgenoessische Technische Hochschule Zurich ETHZ
Priority date: 2020-12-23
Filing date: 2021-12-06
Publication date: 2023-11-01
Also published as: KR20230129179A; WO2022135732A1; US20240049750A1

Abstract

The invention relates to a product having a foam structure with a set ratio of gas pores open to the product surface and closed to the product surface. The invention also relates to a method with four embodiments according to the invention for the defined mechanical opening of closed foam pores. Furthermore, the invention relates to a device having four embodiments according to the invention for the defined mechanical opening of closed foam pores. The invention also relates to the use of products designed according to the invention as meat analogues or plant protein-based textured multiphase foods, more particularly vegetable or fruit composites. Particular advantages of the invention relate to the targeted influencing of the deformation and texture properties of foamed products and their accessibility from the outside for quick and easy filling of the open pores with fluid systems which introduce additional functionalities into the product.

Description

Foamed, elastic, protein-based product, method for

Manufacture of such products, in particular extruded meat analogues based on plant proteins and plant fibres, apparatus for carrying out such a method and use of the product for the manufacture of meat analogues based on plant proteins

Description Genus

The invention relates to a foamed, elastic, protein-based product.

Furthermore, the invention relates to a method for producing such a product with a defined degree of pore opening.

The invention also relates to a device for carrying out the method according to the invention.

Finally, the invention relates to the use of the product according to the invention as the main component for producing meat analogs based on plant proteins. State of the art

Viscous masses can be foamed in extruders, in which gas is metered in under atmospheric or excess pressure, mixed/dispersed and/or partially or completely dissolved under excess pressure, is then released again by pressure relief and remains partially or completely incorporated in the viscous mass to form a foam /1,2 /.

Another known possibility is the addition of foaming agents, which form a gas as a result of a chemical/physicochemical and/or thermal reaction, which is also partly or completely incorporated into the viscous mass with the aid of mixing/dispersing processes to form a foam. Corresponding viscous masses can be of a synthetic and/or biological nature or also consist of mixtures of such and can be the basis or component of products in the food, cosmetics, pharmaceuticals, building materials or plastics industries. In extruders, viscous masses foamed in this way are conveyed by the extruder screws and pressed through an extruder die. As a result of the narrowing of the flow cross-section at the transition from the extruder housing to the extruder nozzle, a static pressure build-up takes place, which in the nozzle is reduced again to atmospheric pressure at the extruder nozzle outlet with the nozzle cross-section being kept more or less constant via the flow shear stresses prevailing there due to wall friction and internal fluid friction. The pressure build-up in the die inlet zone (before entry into the die) compresses the gas trapped in the foam bubbles and thus reduces the size of the foam bubbles, the pressure reduction in the extruder die down to the outlet atmospheric pressure allows the gas in the foam bubbles to expand again and thus enlarges the foam bubbles. bigger Gas bubbles can be deformed in the nozzle flow compared to smaller gas bubbles at lower flow stresses and, if a critical stress is exceeded, they can be broken up and thus converted into smaller bubbles.

As a rule, the aim is for a material strand with a defined shape to emerge from the extruder nozzle, since the product is also typically shaped by means of the extruder nozzle. The dimensional accuracy of such products is often also an important quality measure. This is achieved, among other things, by realizing a uniform laminar flow in the nozzle, which corresponds to a planar layered flow. If a foamed fluid system is moved in such a nozzle flow, there is increased shearing of the fluid system at the nozzle wall due to the typical parabolic flow profile, whereas no shearing occurs in the middle of the nozzle channel. Cross-mixing of the fluid system flowing in this way does not occur (parallel layered flow) provided the nozzle channel does not have any flow obstacles. The maximum wall shear rate present in the fluid layer in contact with the wall (= speed of the fluid film close to the wall under consideration on its side facing the center of the nozzle channel divided by the fluid film thickness) usually causes the formation of a boundary layer close to the wall. If the fluid system contains disperse components, these are set in rotation as a result of the wall shear rate effective in the fluid layer close to the wall under consideration and experience a dynamic buoyancy force (lift force), which causes the disperse components to separate away from the wall in the center of the nozzle channel. This applies in principle to solid particles /3/ but also to gas bubbles /4/ and leads to a depletion of the fluid layer close to the wall of such disperse components. When extruding meat analogues based on plant proteins, the "High Moisture Extrusion Cooking (HMEC)" process is preferably used. This means high temperature (up to approx. 170°C) and high static pressure (up to approx. 100 bar). Extrusion under product water contents of up to about 70% by weight In an aqueous protein melt produced under these conditions, protein denaturation takes place in the form of protein fibrils that form, which are oriented in the direction of flow in the extruder nozzle inlet flow as a result of stretching flow components that are effective there and as a result of subsequent cooling (to approx. 60°C) in a long (> approx. 1 m) extruder cooling nozzle in this oriented structural state. The cooled product emerges from the extruder nozzle as a smooth strand with typically laminar nozzle flow. The oriented protein fibrils give the product a meaty fibrous texture /5/ As a result of the slow cooling of the product in d The extruder nozzle suppresses a sudden release of water vapor and thus does not disturb the formation of the structure.

The prior art with regard to HMEC extrusion processes for the production of plant protein-based meat analogues is described, for example, in patent specifications US6,635,301 B1, WO2016/150834 A1, EP1182937 A4, WO2009075135,

US20050003071 A1, WO2016150834 A1 and US 10,716,319 B2 are comprehensively described. US 10,716,319 B2 (Method of making a structured protein composition) is considered from a technological point of view as the closest description (closest state of the art) to the technology according to the invention described in this patent application: (Translated abstract from US 10,716,319 B2): “The fibrous composition obtained in the extruder leaves the extruder at a temperature of the composition that is higher than the applicable boiling point of water (e.g. 100 °C at atmospheric pressure or lower if one vacuum port is used). It is believed that this leads to expansion and subsequent collapse of the textured product. It is further believed that the expansion/collapse treatment disturbs the fiber orientation and thus leads to the creation of a more random orientation of the formed fibers. In addition, it is assumed that air pockets (on a micro and macro scale) are formed in the textured product. To fine-tune mouthfeel (bite), tenderness and juiciness, after the texturing process, the extruded product can be hydrated in an aqueous liquid at elevated temperatures, i.e. between 40 and 150°C, to a final moisture content of 50 to 95%. Cut tests are most commonly used to measure extrudate tenderness, such as a Warner Bratzler shear blade // or a Kramer shear cell //. The product of the invention has a heterogeneous structure and a relatively large free volume. This contributes to its relatively high water absorption capacity. This is beneficial because the absorption of aqueous liquids makes it easier to add desired flavor components and allows the product to be varied in terms of juiciness and bite. The extrudate according to the invention is infused into the moist product obtained by extrusion. In contrast to the background art, the extrudate of the present invention does not require drying and rehydration. It remains substantially moist and is then further filled with water or other aqueous composition by infusion. The extrudate preferably has a water content of from 55% to 70% by weight. The structured vegetable protein composition resulting from infusion with an aqueous liquid preferably has a water content of from 70% to 90% by weight. Surprisingly, the above-mentioned infusion can be enhanced (ie drain more quickly and/or allow more water to be incorporated) by an aqueous liquid if the extrudate has been frozen first (and then thawed prior to infusion). Preferably the freezing temperature is below -5°C and -15°C."

The microfoaming of highly viscous and viscoelastic, dough-like, protein and non-protein-based masses by means of extrusion processes is described in WO 2017/081271 A1.

The state of knowledge on food foam systems is, for example, in Peter J. Hailing & Pieter Walstra (1981) Protein-stabilized foams and emulsions, C R C Critical Reviews in Food Science and Nutrition, 15:2, 155203, DQI:10.1080 /1040839810952 7315 and in Ashley J Wilson (1989) Foams: Physics, Chemistry and Structure; Springer Verlag London, ISBN 978-1-4471-3809-9.

The production of open-pore foams is known from the plastics/foams industry (N. Mills (2007); Polymer Foams Handbook; Hardcover ISBN: 9780750680 691;

Imprint: Butterworth-Heinemann). Conventional extrusion processes, in particular cooking-extrusion processes in the field of food, building materials and animal feed applications, produce pores that are only reproducible within wide limits and are not reproducible due to the sudden evaporation of water/solvent at the extruder nozzle outlet. The product (extrudate) experiences the formation of a foam-like structure, which is realized by the sudden evaporation of the water as a result of the pressure drop.

In more recent extrusion/cooking extrusion processes, a foamed product can also lead to a product with a better controlled foam structure by means of gas metering and gas dispersion or gas dissolution and renucleation of gas bubbles. However, such products typically have closed pores and, as they flow through the extruder die, form a skin layer largely free of foam bubbles and pores as a result of the maximum shear near the wall.

For foam extrusion applications, it is essential to control the foam pore structure in order to adjust the product properties in such a way that the ratio of closed and open pores can be adjusted.

Open pores enable the rapid absorption of liquid by capillary forces in certain applications, e.g. in instant products, closed pores are desirable when setting the lowest possible product density, obtaining a foamy/creamy mouthfeel (food) or reducing the absorption rate of fluid (foam bubbles as mass transport barriers). ). For a certain range of products from different areas of application, the adjustability of the ratio of closed to open pores is essential for the development of certain quality features. Typical examples of this are fish feed pellets which, in terms of their rate of sinking or their swimming behavior, point to certain species of fish, which typically take up their feed from the bottom of the water body (from floating at a certain water depth or swimming from the surface).

So far, there is no industrially relevant solution for food products with a high content of bound water, such as plant protein-based meat analogues, which have up to > 60% intermolecular water formation, in order to close such on the one hand through defined adjustable (i) microfoam formation and (ii) ratio more open To optimize the consistency of the foam pores and thus to optimize the sensory texture and, on the other hand, to realize an adjustable, additional, particularly production-relevant, rapid (second range) fluid absorption capacity in order to optimize e.g. juiciness and certain further processing properties in e.g.

It is known from KR 1020200140499 A to produce a foam structure, with random gas inclusions being produced. It is also proposed to influence a change in the gas inclusion layers and their shape by means of empirical formulation changes, which, however, is again not possible in a targeted manner. A stochastic porous structure is created at the extruder nozzle outlet, which can hardly be influenced in terms of process technology, since it is an uncontrolled rapid expansion. Provided long-chain elastic gluten molecules are present, such steam expansion is counteracted to a greater extent and a less expanded product is thus obtained. This technically uncontrolled production of porous extrudate products is transferred to meat analogues containing gluten.

It is previously known from 2020/0060310 A1 to produce a porous structure by “puffing”. This is understood to mean a sudden expansion which cannot be adequately controlled with regard to the resulting porosity and certainly not with regard to a defined degree of pore opening.

tasks

The invention is initially based on the object of producing a foamed product with a high bound water content, in the case of extruded meat analogy based on a concentrated vegetable protein melt with > 30% by weight vegetable protein content and > 5% by weight vegetable fiber content and a gas volume content in the end product of > 10 vol. % to create, whereby the gas volume is in the form of pores/bubbles, which should be present in an adjustable proportion as pores open to the product surface, e.g. in order to accelerate further liquid absorption, with sensory and/or nutritionally relevant components contained in this liquid in the to ensure product.

Furthermore, the invention is based on the object of providing a method with which such products can be produced. In addition, the invention is based on the object of providing a corresponding device that enables the method.

Finally, there is the object of using such a product, for example for the production of plant protein-based meat analogs/meat alternatives.

Solution of the task concerning a product

This problem is solved by the features of patent claim 1.

Some advantages

The new, foamed products according to the invention allow, via the setting of the foam pore opening degree, a coupled setting of certain sensory and nutritional attributes as "intrinsic" properties of these products, which have not been possible for conventional products of this category or only to a small extent through additional products (sauces, toppings, etc.). ) could be achieved. In the case of foamed, plant-based protein-based meat analogs, the (a) sensory quality attributes that are relevant for the consumer: tenderness, juiciness, crispiness, meat taste/aroma, (b) nutritional functionalities (e.g. through the introduction of bioavailable iron and B -Vitamins) and (c) convenience properties by enabling or improving the ability to cook, roast and grill, made available in a way that can be adjusted. The formation of a foam structure in a highly viscous to semi-solid product significantly influences its mechanical behavior in the direction of a more easily deformable/softer material. With such products in the food sector, such as extruded, foamed plant protein-based meat analogs, one would state a less compact, hard or "tender" consistency through foaming. If it is (A) a closed-cell foam system, the compressibility of the The gas trapped in the pores contributes to the deformation behavior of the foam product. The elastic recovery is supported by the re-expansion of the gas trapped in the pores when a deforming force is removed, and also dominates with a high proportion of gas volume. In the case of (B) open-pored foams, the gas in the pores can of the foam matrix, escape more or less quickly, depending on the pore size.

In the case of foamed foods, which undergo significant deformation by biting and chewing when consumed, a closed foam pore structure (A) enhances the sensory texture impressions of (i) tenderness but also (ii) gumminess in the case of solid structures of the Foam lamellae surrounding gas bubbles and (iii) creaminess (creaminess) in the case of fluid foam lamellae properties. Open-pored, spongy foam structures (B) allow the sensory textural attributes (iv) crunchyness but also (v) brittleness to come to the fore with firm foam lamellar properties. The case of fluid foam lamellar properties is irrelevant for open-pored product systems, since deliquescence of the matrix material leads to a foam with closed pores.

In the case of defined foamed matrices of plant protein-based meat analogues, which have a fixed structure of the foam lamellae surrounding the gas bubbles, the consumer wishes/consumer ideas address in particular fibrousness as sensory texture attributes combined with tenderness and as other important attributes juiciness and Crispness/bite/crispness (crunchiness), often in the context of certain preparation methods (e.g. boiling, roasting, grilling).

In the case of such foamed meat analog products with at least partially open pores, their sensory, nutritional and preparation convenience properties can be significantly expanded in that the pores of the foamed base product are partially or completely filled with functional or functionalized fluids, such fluids after pore filling can also solidify. By means of such "fluid fillings" of the open-pored meat analogues, specific taste and aroma-related sensory and/or nutritional product properties can be ten and, if necessary, optimize the product stability with preserving components.

The filling of open pores can take place, for example, by capillary forces which, given coordinated wetting properties of the filling fluid phase, allow the fluid to be sucked in as a result of the formation of a capillary negative pressure. Since such capillary forces are inversely proportional to the pore diameter, small pore diameters in the range <approx. 500 micrometers are preferable.

The subject of the invention is based on a HMEC technology as described above for the preferred production of plant protein-based meat analogues, with this technology being significantly supplemented by a combination with a micro-foaming process, which takes place in the extruder and in a comparable manner, based on the production of foamed baked goods was described in 121. A defined amount of gas (e.g. N2, CO2) is first dissolved in the aqueous protein melt in the extruder under the high pressure set there and then released again by reducing the pressure in the extruder cooling nozzle. Gas bubbles are nucleated at the beginning of the extruder nozzle and enlarged as the nozzle flow progresses with progressive pressure release, thus forming a foam structure. Furthermore, the description of the present subject matter of the invention is based on this foaming technology and its transferability to the production of meat analogues foamed in this way, produced using HMEC technology. The product-related focus of the subject matter of the invention described below is on the plant protein-based (foamed) meat analogues, which make available innovative adjustment options for sensory and nutritional product characteristics of significant consumer relevance through the adjustability of the ratio of closed to the product surface open pores/pore channels.

The cooling of the product flow from the HMEC extruder close to the wall at the entrance to the extruder nozzle, which begins during the production of meat analogues, allows under the still prevailing high pressure and the already noticeably reduced temperature near the nozzle wall (from typically approx. 140-160°C to approx. 90 °C) as a result of the improved gas solubility at lower temperatures, fewer foam bubbles form near the nozzle wall.

The (i) high shear of the cooling, foamed protein melt in the vicinity of the nozzle wall supports, in addition to the named effect of (ii) improved gas solubility, a (iii) reduction in gas bubbles due to flow effects (dynamic buoyancy forces) in the nozzle wall zone. The "skin layer" of the extruded, foamed meat-analog strand, which is partially or completely depleted of gas bubbles, shields inner foam pores from the environment. As a result of the typically slow product cooling in the Fleischanalog-HMEC Extrusion used long cooled extruder nozzles no more significant residual pressure relaxation occurs at the nozzle outlet, a product skin layer formed as described remains closed. For the micro-foamed products this means the presence of a closed foam pore system.

For a number of applications or final product formats, it is advantageous to create open, spongy pore systems which are able to absorb liquids through outwardly open pores in the porous (spongy) product matrix. Fluids absorbed in such a form can interact with the matrix structure, retain fluid character or solidify or partially solidify under the framework conditions to be set (e.g. temperature). For example, food systems equipped with such open-pored porosity could absorb liquids that impart juiciness to the food in question. For building materials with a corresponding pore structure, suitable fluid systems for impregnation could result in improved resistance to mould/fungus infestation or harmful insects. For applications in wound healing, covering material with a correspondingly open-pored, porous structure can be impregnated with fluids for disinfection or fluid components that promote wound healing.

Against this background, there is great interest in adjusting the pore structure of foamed product systems in an application-specific manner in extrusion processes. Accordingly, the subject of the invention addresses a technology for adjusting the ratio of closed pores/bubbles to open pores/pore channels that are open towards the product surface. In principle, this can also be achieved mechanically by connecting originally closed foam bubbles/pores, provided that these can be brought to coalescence or the formation of connecting channels between them and to the product surface in a defined manner, without significant loss of the total gas volume fraction and fine pores.

According to the invention, the pore volume ratio E=EOP/S (SOP=porosity of the open pores; s=total porosity) is adjustable by means of various specific measures in their individual or coupled application. These pore opening technologies POTi according to the invention can be found in Table 1 and are described in detail below.

POT-1 :

A slit-nozzle aperture (VSDA) according to the invention, which can be adjusted in the gap width, is arranged just before the end or at the end of an optionally shortened extruder slit nozzle and narrowed to a position which reduces the static pressure before entry into the narrowed slit gap to a value of approx. 1.5 -2 bar of the static pressure prevailing after exiting the slit gap, which is typically atmospheric pressure, can be adjusted. With this procedure according to the invention, the strand of extrudate is not Cut off directly at the nozzle exit, but only from a length of 5-10 cm. The shorter length distance between the middle of the extrusion strand and its surface compared to the length of the extruded product strand up to the strand cutting device is approx. 1/2 - 1/6. According to the invention, this brings about a preferred gas pressure relaxation in the product cross-sectional direction and thus towards the product surface. This is due to the significantly greater pressure gradient realized in this direction compared to the pressure gradient prevailing in the strand length direction. The characteristics of the pore channels formed in the direction of pressure release and their opening outwards towards the surface of the extruded strand is decisively determined by the rheological properties of the extruded product at the time it emerges from the extruder die. Lower viscosity (or elasticity) allows more pronounced material deformation under the effect of the relaxation pressure gradient and, as a result, more pronounced pore channel formation.

The embodiment of the geometry of the adjustable slot nozzle device (VSDA) according to the invention enables a different geometric shaping of the course of the flow cross section in the direction of flow. According to the invention, the constriction is preferably abrupt (approx. 90°), which forces the formation of a secondary flow of the extrusion strand fluid in the zone of the widening again of the flow channel cross section. In this follow-on secondary flow zone, the static pressure is significantly lowered and, on the other hand, a roller-like secondary flow is generated, which causes the strand fluid to be mixed transversely to its direction of flow in the vertical direction of the slot nozzle channel. The "inside-out turn" of the extrusion strand material depends on the intensity of the secondary därstrom and their rotation frequency. Since the strand material is located just before the nozzle exit or directly at it, there is no possibility of a renewed formation of a closed skin layer on the product strand, which would lead to renewed pore closure. This results in the formation of pores/pore channels that remain open towards the surface of the extrusion strand.

The products according to the invention, produced by the method according to the invention using the device according to the invention, make available novel extrusion products with a defined foam structure. These form a practical basis for new product developments:

(a) with adjusted volume ratio of open and closed pores (pore opening degree POG),

(b) without skin/surface layer formation when flowing through the extruder die

(c) with adjustable texture properties (tenderness, crispiness, juiciness)

(d) with extended possibilities of taste/aroma/active ingredient optimization through fluid systems incorporated into the open pores, which contain corresponding taste, aroma or active ingredient components that do not go through the extrusion process, thus avoiding their reduction in functionality and their release Accelerate application (consumption and digestion of food, intake of pharmaceutical products) via the open pore channels).

(e) with expanded possibilities for "instant product" production, which allow accelerated wetting and dispersion in liquids More inventive designs

Further inventive developments are described in claims 2 to 10.

Claims 2 to 5 emphasize the important role of the protein content and the set denatured, possibly anisotropically formed protein structure, since the meat analog products that are preferably considered owe their meat-like texture properties to the denatured, fibrillar protein structures.

Claim 2 describes a product in which the protein content is 10-95% by weight in its dry substance, while claim 3 describes a product in which the protein content is 0-100% by weight of vegetable protein. .

The product in claim 4 is characterized in that the protein in the product is in partially to fully denatured form and has a fibrillar structure, while the product according to claim 5 is characterized in that the denatured form has an oriented fibrillar structure.

Claims 6 to 8 take into account ingredients and their quantities which are of particular importance for the setting of the sensory and nutritional corresponding vegan meat analogues. For this purpose, the product according to claim 6 contains a plant fiber content of 0.5 - 20

% by weight, based on the dry substance.

In claim 7 a product is described in which the product contains a proportion of fats or oils of 0.1 - 15% by weight, based on the dry substance, while the product in claim 8 is characterized in that it contains a proportion of flavoring and /or coloring and/or components that increase the nutritional value in addition to the plant fiber content of 0.1 - 5% by weight, based on the dry substance.

Claims 9 and 10 address a surprisingly found special feature of the foamed products according to the invention with an open pore fraction, which represents their volume, shape, structure and texture-related reconstituting work after almost complete drying. The influence of the degree of pore opening has a decisive influence on the acceleration of water transport from the moist product and into the dry product both during drying and during reconstitution.

For this purpose, claim 9 proposes a product which, after drying to a residual water content of <5% by weight and spoilage-free, moisture-controlled storage for several months under room temperature conditions, when brought into contact with water or a water-containing fluid system, is restored to its original volume and texture, without loss of dry substance . Claim 10 describes a product which, after drying to a residual water content of <5% by weight and spoilage-free, moisture-controlled storage for several months under room temperature conditions, is reconstituted when it comes into contact with water or a water-containing fluid system, restoring its original volume and texture.

Solution of the task concerning the procedure

This object is achieved by claim 11, which is characterized in that the method realizes the opening of gas pores or gas bubbles enclosed in the foamed product towards the product surface in an adjustable manner, with an extrusion method of the "High Moisture Extrusion Cooking" type (High Moisture Extrusion Cooking, HMEC ) with gas entry, temporary gas solution and controlled gas bubble nucleation as well as foam formation and five process variants for pore opening: (a) opening by rapid ambient pressure drop (flash opening, FOP), (b) opening by dividing or peeling the product (cut opening). , COP), (c) opening by multiple needle penetration (penetration-opening, POP), (d) opening by forced secondary mixed flow (mix-opening, MOP), and (e) opening by freeze-patterning (freeze-opening, FOP) individually or be applied in coupling, whereby the opening of gas pores trapped in the foamed product or

Gas bubbles towards the product surface is realized in an adjustable manner. Some advantages

The method according to the invention and its configurations can be coupled directly to the HM EC extrusion process and the extrusion parameters to be set for structuring the protein matrix for the pore opening can be directly transferred. Thus, for the mechanism of (a) pore opening by rapid ambient pressure drop (flash opening, FOP), the static pressure built up in the extruder can be maintained up to the end of the die to such an extent that a sufficiently rapid and efficient residual pressure relaxation can be realized at the pore opening. With the mechanisms (b) pore opening by dividing or peeling the product (CUT-Opening, COP) and (c) pore opening by multiple needle penetration (Penetration-Opening, POP), the movement or kinetic energy of the extrudate strand at the end of the die is used for cutting/ peeling or used for needle penetration. To activate the (d) pore-opening mechanism through forced secondary mixed flow (mix-opening, MOP), part of the kinetic flow energy of the extrudate strand is used to generate a cylindrical secondary flow that also periodically oscillates for viscoelastic masses, which is transverse to the flow in the vertical direction of the extruder Slot nozzle causes a thorough mixing, which elongates closed foam pores, moves them towards the surface of the strand and "tears open" the surface structure in such a way that the intensity can be adjusted, so that a part of the correspondingly treated pores, which can also be adjusted, is opened towards the product surface. The adjustability of the degree of pore opening is based on the adjustability of the intensity of the mixed secondary flow, which in turn can be adjusted within wide limits by adjusting a local slot nozzle height reduction and the transport speed of the extrudate strand (e) for pore opening by freeze structuring is used according to the invention on foam structures in order to penetrate primarily large ice crystals for penetrating material partitions between closed pores at a preferably slow freezing rate and thus convert them into open pores. The high water content (up to 60% by weight) of the plant protein-based meat analogues considered as preferred helps to support the formation of ice crystals.

More inventive designs

Further inventive developments are described in claims 12 to 25.

According to claims 12 to 21, the pore-opening processes are detailed in their technical implementation by means of mechanisms (a)-(e), (a) mobilizes compressive forces to break open pore boundaries outwards towards the product surface. (b) uses targeted incisions to expose the pore openings, (c) creates connecting channels between the closed product pores and outwards to the product surface through needle penetration, (d) refers to the generation of secondary flows in the extruder cooling nozzle in order to create largely closed flows in the laminar slot nozzle flow Breaking up product skin layers by cross-mixing in the height coordinate direction of the nozzle channel and creating additional superficial transverse channels/channels. For the protein-rich, meat-analogous product systems, which are primarily addressed, an additional flow-dynamic feature of viscoelastic fluid systems can be advantageously used according to the invention. The so-called elastic turbulence effect (partly in which the artificial Material processing related literature also referred to as "melt fracture phenomenon") arises as a result of the elastic deformation energy storage in the converging inlet flow of a slot nozzle aperture (VSDA) designed according to the invention and arranged in a defined manner in the nozzle channel and adjustable with regard to slot channel constriction. In the diverging Outflow flow after the constriction, the previously stored elastic tensile stresses partially relax again through elastic reverse deformation of the viscoelastic fluid (e.g. a protein melt corresponding to meat analogs extruded in HMEC). As surprisingly shown on the basis of rheological laboratory measurements for a large number of polymer melts, the above-described secondary flow ph phenomena with a ratio of the first normal stress difference Ni to the shear stress T from a value of NV T > 1.5 - 2 and becomes particularly effective in a range Ni/ T = 4-5 in order to achieve the described inventive effect of the sinusoidally oscillating secondary mixing flow (OSMS) in the after-run of a local slot die narrowing for cross-mixing in the extruder die for the pore opening towards the product surface, to be used purposefully. The OSMS can thus be set in the range 2<TW/NI<5 in its process-relevant intensity according to the invention, TW and Ni can be measured both in rheometric laboratory measurements using a cone-plate shear gap and in high-pressure capillary rheometric measurements. According to the invention, the latter are also transferred directly to in-line measurements in the extruder slot die. According to the invention, this is done by means of static pressure profile measurements in the nozzle channel before and after the local slot die height reduction or alternatively in the extruder-side die entry zone. According to the invention, the intensity of the OSMS is measured via the amplitude of the static pressure fluctuation in the slot nozzle channel before or after the local slot nozzle height reduction. The setting of a maximum elastic-turbulent OSMS via an adjustable aperture according to the invention for local slot nozzle height reduction is possibly limited by the fact that an excessively fragmented product strand at the nozzle outlet is to be avoided. This is achieved in that the variable slot die aperture (VSDA) device according to the invention is installed in the extruder cooling die, typically in the first two thirds of its length. In this way, the elastically-turbulently mixed product strand is partially evened out again in a defined manner in the laminar layer flow that is restored after the aperture and crack formations in the structure are gradually healed again, if desired. In order to avoid the renewed formation of a skin layer of the product strand with associated pore closure towards the product surface, the degree of OSMS adjustable via the VSDA as described and the length of the extruder nozzle in the aperture wake are matched according to the invention or calibrated specifically for the material system.

Claims 22 and 23 refer to the possibility of drying the products after the pore opening has taken place according to one or a combination of methods (a)-(e) in order thereby to achieve an extended shelf life at ambient temperature storage. According to the invention, the opening of the pores advantageously accelerates the transport of water during drying and also during reconstitution. According to patent claims 24 and 25, the basic conditions for the accuracy of setting the degree of pore opening and the underlying total gas pore volume in the product, which should have or should have an open connection to the product surface, are specified. The resulting bandwidth from (i) a minimum of 10% by volume total gas content (in pore form) with 5% open to (ii) a maximum of 80% by volume total gas content (in pore form) with 90% open is relevant for foamed meat analogues, for example in case (i), for example, to achieve easy penetration with intensively flavoring substances in fluid form, and in case (ii), for example, to homogeneously penetrate 72% of the product volume with a fluid phase that gives consistency/texture and that may solidify after pore filling. In the latter case, application to meat analogues resulted in a scaffolding protein structure with, for example, a vegan pie/sausage filling. In the area between (i) and (ii), "marbled" product structures with an adapted fat/gel insert can be realized in order to further adjust typical meat/fat/connective tissue/gel structures and associated sensory preferred texture properties.

According to claim 25, the gas-filled volume fraction is limited to 80% by volume, since the pore opening mechanisms according to the invention, which are related to rather solid foam products, can no longer be transferred sufficiently non-destructively to the overall product if the foams are too fragile. Solution to the problem relating to the device

This object is achieved by claim 26, which is characterized in that the extrusion nozzle is followed by a cutting device and a conveyor belt that is partially perforated in the middle in sections of the cooling nozzle of an HMEC foaming extruder, and the conveyor belt with the cut-off part of the product lying on it is guided between two vacuum half-shells , which sealingly enclose the conveyor belt and product by pressing against each other from above and below, and these vacuum half-shells are connected to a vacuum storage container via a vacuum line provided with a valve for quick opening and this to a vacuum pump for the sudden application of a partial vacuum to the foamed extruded product are.

The pore opening mechanisms use mechanical, fluid mechanical or thermodynamic principles to open closed pores to the product surface by means of a:

(a) device variant for setting a rapid drop in ambient pressure (flash opening, FOP),

(b) Device variant for cutting or peeling the product (CUT-Opening, COP) in the exit area of the extruder cooling nozzle,

(c) Device variant for multiple needle penetration (penetration opening, POP) directly after the partially cooled product exits the extruder cooling nozzle (d) Device variant for generating a secondary mixed flow (mix opening, MOP) in the extruder cooling nozzle.

(e) Device variant for generating large ice crystals for foam lamella penetration by means of freeze structuring (freeze opening, FOP) in a post-treatment for quench cooling after extruder cooling nozzle exit, which can be used in individual or coupled applications.

The core element of the devices for activating the pore opening mechanisms according to (a) and (d) is a variable slot nozzle aperture (VSDA). Their free cross-sectional area for the passage of the extrudate corresponds exactly to the dimensions of the free cross-section of the extruder slot nozzle when it is 100% open. In the case of a flat, right-angled extruder nozzle slot channel, a cut, rotatably slide-mounted metal cylinder (2) is embedded in the aperture housing (1) in a sealing manner in the upper and lower walls delimiting the flow slot of the aperture device over the entire slot width, perpendicular to the direction of flow. When the aperture is fully open, the gate surfaces of these cylinders are flush with the flow channel wall (3). From outside the aperture housing (1), the metal cylinders (2) can be rotated manually or by means of two servomotors in a controlled or regulated manner so that the aperture narrows on one side or is symmetrical to the longitudinal axis of the nozzle, which at a twist angle of 90° corresponds to the maximum The degree of closure of the slit channel cross section corresponds to (further details, see description of the figures, FIG. 1). Activation of the pore-opening mechanism d) to generate a secondary mixed flow (mix-opening, MOP) in the extruder cooling nozzle can take place solely by means of the VDSA device. In case (d), this is integrated into the nozzle at a position between 10-95% of the nozzle length measured from the nozzle exit end. In the case of a severely disintegrated extrudate structure, this ensures that this reintegrates to a part on the remaining stretch of the die after the passage through the aperture, thus preventing the extrudate strand from disintegrating at the die outlet.

To utilize the pore opening mechanism (a) as a result of sudden residual pressure release, the VDSA device is integrated into the nozzle in a position between 0-10% of the nozzle length measured from the nozzle outlet end. This ensures that the abrupt relaxation of the static residual pressure and thus the opening of the pores towards the extrudate surface only takes place shortly before the nozzle exit or directly at the nozzle exit.

If the extrudate is additionally suddenly subjected to a partial vacuum to open the pores, cut off extrudate parts are post-treated in a separate, quasi-continuously operating vacuum device directly after the nozzle outlet. This additional treatment variant is preferably used for softer extrudates which, in the case of protein-based meat analogs, have a higher die outlet temperature or a higher water content. When using the pore opening variant (c) for multiple needle penetration (Penetration-Opening, POP) directly after the exit of the partially cooled product from the extruder cooling nozzle, in the preferred embodiment of the device according to the invention at the extruder nozzle outlet there are two counter-rotating hollow needle or barb felt needle rollers attached in such a way that the needles penetrating the extrudate from both sides mesh and the rotation of the needle rollers preferably takes place without an auxiliary drive, solely by the feed of the extrudate through the gap between the two needle rollers (for further details see description of the figures, Figure 5).

When using the pore opening variant (c) by means of cutting or peeling the product (CUT-Opening, COP) in the exit area of the extruder cooling nozzle, a cutting/paring knife arrangement is arranged shortly before the exit or directly at the exit of the extrudate strand from the extruder nozzle. The extrudate strand feed is thus used to implement the cutting forces. Internal foam pores are thus opened towards the newly created product surface. This is indicated in particular when a "skin layer" with fewer foam pores has formed in the nozzle flow.

Some advantages

With the exception of the additional vacuum application to activate the pore opening mechanism (a) to set a rapid drop in ambient pressure (flash opening, FOP) and freeze structuring to activate the pore opening mechanism (e) to penetrate the pore wall using ice crystals (freeze opening FOP). all other devices have a simple structure and are arranged directly in or coupled to the extruder nozzle. This results in the particular advantage of the direct linkability of these mechanisms and the associated device variants. All of these devices are insensitive to contamination, mechanically robust and easy to preset, so that no further manipulations are required during the production process.

The opening of the pores can be carried out effectively and reproducibly by means of the devices configured according to the invention, the quality and degree of the opening of the pores still being determined by the material behavior of the extrudate. This must have a basic strength or yield point which ensures that the open pores produced are not closed again by the matrix mass flowing together. Due to the fact that the pore opening mechanisms (a)-(e) can be superimposed, which is advantageous in accordance with the invention, and the devices according to the invention provided for this purpose, a sufficient pore opening efficiency can also be ensured for critical, soft extrudates.

More inventive designs

Further inventive developments are described in claims 27 to 34. Solution of the task regarding the use

This object is achieved by the features of claim 35, which is characterized in that the resulting foamed product with a set pore opening degree is used as a structured base element for meat analogs, the proteins used being only of vegetable origin and such meat analog base elements used in menus which bring about a gradual to complete filling of the open pores of the structured base element with complemented, fluid sauce or juice or dressing or marinade or topping components.

More inventive designs

A further advantageous use or embodiment is described by the features of claim 36.

Some advantages

Fibril-structured meat analogs that can be produced using high moisture extrusion cooking (HMEC) technology based on plant proteins have a compact structure that does not come close enough to the comprehensive sensory requirements of consumers for really comparable texture, taste and some nutritional properties of meat to be considered as real alternative to be accepted. the The product structures that can be achieved according to the invention with an adjustable ratio of closed and open pores allow the attributes required for meat analogues to be met in that they can be used purposefully on the one hand to give a positive texture (tenderness, crispiness) and on the other hand to give taste (juiciness) via the simple absorption capacity of fluid systems. The fundamental non-restriction of the technology package according to the invention to meat analogues also creates a broad implementation horizon for other foamed food systems. Implementations on pharmaceutical and cosmetic products as well as on construction/construction materials are also application horizons that can be notified.

In the drawing, the invention is illustrated, for example, partly schematically. Show it:

FIG. 1 shows the variable slot nozzle aperture (VSDA) according to the invention for a flat slot nozzle. The following designations apply in Figure 1: 1 = aperture housing, 2 = truncated rotatable, slide-mounted metal cylinder - 2a in O-position with free flow cross-section, 1 b turned clockwise, 2c turned counter-clockwise, 3 = slot nozzle wall, 4a - 4c = Aperture inlet flow for the differently rotated metal cylinder settings according to 2a-2c, 5a - 5c = aperture outlet flow for the differently rotated metal cylinder settings according to 2a-2c, 6 = geometric designations for positioning the metal cylinders, a = angle of rotation of the metal cylinders, ß = angle between metal cylinder center and edges of the gate surface of the metal cylinder. The basis of calculation for the defined reduction in height of the extruder nozzle flat slit channel as a function of the rotation angle 5 of the metal cylinder to be rotated and as a function of the metal cylinder radius R1 as well as the placement of the gate surface (angle ß) and the center coordinate R1 of the metal cylinder thus determined are shown in Figure 8 .

In the case of a flat, right-angled extruder nozzle slot channel, in the upper and lower walls delimiting the through-flow slot of the aperture device, over the entire slot width, at right angles to the direction of flow, a cut, rotatably slide-mounted metal cylinder (2) seals into the aperture housing (1), but is rotatable admitted. When the aperture is fully open, the gate surfaces of these cylinders are flush with the flow channel wall (3). From outside the aperture housing (1), the metal cylinders (2) can be rotated by hand or by means of two servomotors, so that the aperture narrows on one side or symmetrically to the longitudinal axis of the nozzle, which corresponds to the maximum degree of closure of the slot channel cross-section at a twist angle of 90° .

In the case of a ring slot die, which is used for increased extrudate mass flows, the mechanism for adjusting the height of the slot gap is implemented via a concentric, conical design of the inner wall of the die housing and an axially displaceable stamp with a conical tip, as shown in FIG. The following designations apply to Figure 2: 7 = conical nozzle housing, 8 = axial gap setting stamp with conical tip, 9 = insertion stamp guide tube, 10 = tempering fluid inlet into setting stamp guide tube, 11 = tempering fluid outlet from setting stamp guide tube, 12 = tempering fluid channels in inner (12a) and outer (12b) nozzle housing walls as well as in the setting stamp (12c), 13 = guides for axial setting stamp guide tube, 14 = nozzle gap in initial position (14a) and with narrowed gap setting (14b), 15 = annular slot nozzles inner housing wall part, 16 = Flange for connecting annular die parts or with extruder housing

The device according to the invention as shown in FIG. 3 is used for the additional post-treatment according to the application of the pore opening mechanism (a) for pore opening by means of a rapid drop in ambient pressure (flash opening, FOP) by means of partial vacuum application.

The following applies to the designations in FIG. 3: 17=slit nozzle flow channel, 21=extrudate strand, 26=partially perforated conveyor belt, 27a=upper vacuum half-shell, 27b=lower vacuum half-shell, 28a=contact pressure pneumatics for upper vacuum half-shell shell, 28b = contact pressure pneumatics for lower vacuum half-shell, 29 = cut off extrudate part, 30 a,b = pipelines for suction (partial vacuum transmission), 31 = partial vacuum storage container, 32 = vacuum pump, 33 = strand cutting device P0T2: The device implemented according to the invention for opening the pores according to mechanism (c) by means of cutting or peeling the product (CUT-Opening, COP) applies a cutting/paring knife (possibly water jet or laser cutting devices) in the exit area of the extruder cooling nozzle - arrangement as shown schematically in Figure 4 shown.

The designations in FIG. 4 are: 17=slot nozzle flow channel, 18=laminar slot nozzle flow, 19=cutting device for positioning above the slot channel height H, cutting device for positioning above the slot channel width \N.

POT3: The device for realizing the pore opening according to mechanism (c) for multiple needle penetration (Penetration-Opening, POP) is arranged directly after the extruder nozzle exit and combines in the preferred embodiment of the device according to the invention two counter-rotating hollow needle or barb felt needle rollers, where the needles penetrating the extrudate from both sides intermesh as shown in FIG.

The designations in FIG. 5 are as follows: 17=slit nozzle flow channel, 22a=upper needle roller, 22b=lower needle roller, 23=penetration needle (hollow needle or barbed felting needle), 24=conveyor belt dividing device, 25a, b=upper, lower penetration needle rollers pressing Divider (pneumatic/hydraulic/mechanical). POT-4: The device for realizing the pore opening according to mechanism d) for generating a secondary mixed flow (Mix-Opening, MOP) in the extruder cooling nozzle can in principle be limited to the Adjustable Slot Nozzle Aperture (VSDA) device, for in -line control of the intensity of the set secondary mixed flow, however, the coupling with a measuring arrangement according to the invention for determining the static pressure before and after the VSDA device is indicated. This pressure measurement arrangement is shown in combination with the VDSA device in FIGS.

FIG. 7 contains an expansion of the pressure measurement arrangement from FIG. 6 for the case of viscoelastic fluids, as are present in the case of protein melts for the production of meat analogues.

The designations in FIGS. 6 and 7 are as follows: 1=aperture housing, 2=cut, rotatable, slide-mounted metal cylinder—2b rotated clockwise, 3=slit nozzle wall, 4b=aperture inlet flow for rotated metal cylinder clockwise (2b), 5b=aperture outlet flow rotated metal cylinder in clockwise direction (2b), 17 = slot nozzle flow channel, 35 = diaphragm pressure sensor for static pressure measurement P1; 36 = membrane pressure sensor for static pressure measurement P2, 37 = membrane pressure sensor for static pressure measurement P3, 38 = membrane pressure sensor for static pressure measurement P4, 39 = pressure sensor membranes, 40 = connecting flanges, 41 = conical nozzle inlet flow geometry, 42 = membrane pressure sensor for static pressure measurement P5, 43 = P5 - pressure measurement cavity. For pronounced viscoelastic extrusion fluids, such as those corresponding to foamed protein melts, for example, the aforementioned VSDA is installed according to the invention at a greater distance from the die outlet in the extruder die than in the POT-1 technology. In the case of viscoelastic product fluid systems, the aforementioned secondary flows as a result of adjustable channel cross-section narrowing and widening are significantly forced by the effect of elastic turbulence (relaxation of the elastic extra-normal stresses and the resulting reverse deformation of the strand). This effect can be triggered even with a slight narrowing of the slot nozzle cross-section and its expression can be set and used in a targeted manner to create an open pore structure.

For this purpose, according to the invention, as shown in Figure 6, static pressure measurements are carried out at a position in the extruder housing in front of the nozzle inlet cross section (P1) at two longitudinal positions in the extruder slot nozzle (P2, P3) after the nozzle inlet zone (after the conical narrowing), after the VSDA (P4), and (P5) in the slot nozzle channel in front of the VSDA, directly opposite (slot nozzle channel underside) to the pressure measurement position P2.

From P2 and P3, the local shear stress TW on the slot nozzle channel wall and, knowing the product volume flow dV/dt determined at the nozzle outlet, the product shear viscosity q can be determined. Including P1, it is possible to determine a nozzle inlet pressure loss APein, which is the sum of (i) a viscous extensional pressure loss APo.ein under the effect of the extensional viscosity of the extruded fluid and (ii) an elastic pressure loss component APE.ein as a result of elastic energy storage. tion, results. By means of the additional static pressure measurement P5, a purely elastic parameter fluid response can be determined between the measuring points for P5 and P2 from P5-P2 through reverse deformation as a result of elastic stress relaxation. P2-P5 is proportional to the so-called first normal stress difference N1, which is measured in rheometric laboratory measurements using cone-plate shear gap geometry and can be compared with the values determined in-line or a calibration can be derived from this. The elastic component DPE.ein of the nozzle inlet pressure loss APein can be determined from P2-P5, and thus the complementary viscous expansion component APo.ein of APein is also obtained. The arrangement according to the invention of the pressure measurement points P1-P3 and P4 means that there are separate rheological parameters for (a) the shear viscosity, (b) the elongational viscosity and (c) the elasticity of the extruded mass under the given extrusion conditions. In the case of the pressure measurement P5, it should be noted that this is not carried out like all other pressure measurements (P1-P4) via a membrane of the pressure sensor flush with the wall in the slot die channel, but at the end of a cavity filled with the extrusion fluid, which is used to measure the first normal stress difference from P2 -P5 has a (narrow) rectangular cross-section extending in the direction of flow (eg: with a nozzle channel width of 60 mm: 10 x 50 mm). The pressure measurement P4 takes place at a position in the slot nozzle channel immediately after the constriction created by means of the VSDA device (height reduction of the slot nozzle channel AH). In this way, periodic, static pressure fluctuations DP4(t) generated in particular by a forced secondary mixed flow in the VSDA wake are recorded. According to the invention, these are a measure of the mixing intensity and the associated resulting foam pore opening efficiency according to mechanism (d) identified and described above.

As was surprisingly found in laboratory rheometric measurements for a large number of polymer fluid systems, the "elastic turbulence phenomenon" (also called melt fracture in the plastics industry) shows up in a certain range of the ratio of the first normal stress difference to the shear stress NI(YW)/T(YW). effective wall shear rate g _w on the slot nozzle channel wall. This range is 2<NI(YW)/T(YW)<5. The expression of the elastic turbulence effect used according to the invention for using the mechanism (d) according to the invention of foam pore opening by forced secondary mixed flow preferably takes place in the range 2<NI(Y) /T(YW) < 3.5-5. As this ratio value increases, the secondary mixed flow effect is gradually increased. Depending on (i) the rheology of the extruded fluid system (here preferably vegetable protein-based melt for meat analog production) and the mean flow velocity in the slot nozzle channel, the VSDA device is adjusted with regard to the slot nozzle height reduction in such a way that the intended degree of secondary mixed flow with a correlated pore opening effect results. Thus, by means of material system-specific calibration, a quantitative criterion for setting the VSDA slot opening to trigger or set a gradual expression of the forced "elastic-turbulent secondary flow mixing effect" can be determined, which leads to the pore opening according to the invention using the POT-4 technology and the thus triggered Mechanism (d) enabled in an adjustable manner. The development of the viscoelastic secondary flow effect used for POT-4 can lead to an almost complete disintegration of the extrudate strand. In plastics technology, this undesirable elastic phenomenon is also referred to as "melt fracture". In order to avoid this, the VSDA device is installed according to the invention >0.2 LD (LD=nozzle length) in front of the end of the extruder nozzle. The consequence of this is that the extrudate strand, in the event of partial disintegration in the undisturbed nozzle flow, "heals" again after passing through the VSDA to such an extent that a compact, cohesive, foamed, partially open-pored product strand results without the through repeated flow-related "skin formation". destroying the pore opening effect achieved by elastic-turbulent mixing.

Exemplary representations of plant protein-based meat analog product structures and degrees of pore opening according to the invention achieved with the devices according to the invention using the method according to the invention are described below in FIGS. 8-10.

The basic conditions for the examples given below are:

HMEC extruder: Corotating twin screw BCTL extruder from Bühler AG with a screw diameter of 42 mm and an extruder length to screw diameter ratio of L/D = 28.

Extruder cooling nozzle: L = 1.85m, W = 60mm, H = 15mm

Material/basic recipe: 52.5% water, 0.5% oil, 41.2% pea protein isolate (PPI), pea fiber 5.8% Process conditions: screw speed: 230 rpm; mass flow 37.5 kg/h; Nozzle entry temperature of the melt: 150° C.; Extruder outlet pressure: 18 - 20bar, nozzle cooling temperature: 60°C

Example 1 (see FIG. 9): Pore opening mechanism by means of (a) sudden residual pressure relaxation and (d) superimposed forced secondary mixed flow.

Different degrees of pore opening were adjusted by means of the superimposed pore opening mechanisms by (a) rapid pressure drop (static residual pressure relaxation) and (d) forced secondary mixed flow, generated by means of the adjustable slot nozzle aperture (VSDA) installed at the nozzle outlet end with different settings of the slot channel height reduction AH / %:

• Figure A: AH = 5% / resulting degree of pore opening POG « 3 - 5%

• Figure B: AH « 10% / resulting degree of pore opening POG = 10 -12%

• Figure C: AH « 50% / resulting degree of pore opening POG « 25 -30%

The degree of pore opening (POG) was determined according to:

POG = VOP open pore volume/VGP total pore volume. VOP was determined by placing an extruded sample in water at room temperature (25°C) for 5 s and, after removing the strand surface, free water adhering to it using household paper in a defined, quick handling procedure by placing it on both sides once on a layer of paper for 1 s each , superficially dried. The differential weighing before and after such treatment resulted in the product product pores open towards the surface mass of water sucked in by capillary forces. VGP was determined by determining the volume and mass of the extruded product, from which the proportion of gas volume or overrun (= relative increase in volume due to foaming) was determined in comparison to the non-foamed product.

As can be seen from FIG. 9, the surface of the extrudate shows increasing “fissures” as the height of the VSDA slot die channel increases, as a result of the imposed forced secondary mixed flow with simultaneous residual pressure relaxation. This is a typical image of the resulting product when installing the VSDA at the nozzle end.

The samples taken into account in this example, untreated with regard to pore opening, had a gas volume fraction after foaming of approx. 25-35% by volume in >approx. 98% closed inner foam pores.

Example 2 (see Figure 10): Pore opening mechanism by means of (d) forced secondary mixed flow, generated by means of an adjustable slot nozzle aperture (VSDA) installed with a nozzle length of 0.75 m from the nozzle outlet when the slot channel height reduction is set DH / % ~ 15%.

FIG. 10 shows a predominantly smooth extrudate surface with clearly visible flow patterns originating from the forced secondary mixed flow. These "heal" as a result of the subsequent nozzle flow (here over a further 0.75m of the nozzle length. This reduces the required for the end product to a small extent. targeted degree of pore opening, but allows the production of quality-relevant structural patterns according to the invention to a large extent from the consumer's point of view, which reflects a natural distribution of structural inhomogeneities as in meat products (in the example shown: salmon/fish or marbled Wagyu beef structures). The degree of pore opening achieved under the boundary conditions selected in this example is 18-20%.

The samples taken into account in this example, untreated with regard to pore opening, had a gas volume fraction after foaming of approx. 15% by volume in >approx. 98% closed inner foam pores.

Example 3 (see FIG. 11): pore opening mechanism by means of (d) forced secondary mixing flows. generated by means of an adjustable slot nozzle aperture (VSDA) installed with a nozzle length of 0.3 m from the nozzle outlet when the slot channel is set to a height reduction DH / % ~ 15%.

Figure 11 shows an enlarged image of the product surface. The wavy stripe pattern structures are clearly visible. (H) lighter (more foamed) and (D) darker (less foamed) areas alternate in strips. The H areas originate from the inner strand foam structure, which is conveyed to the product surface by the forced secondary mixed flow. The D-areas originate from the original "surface-

skin layer". The samples taken into account in this example, untreated with regard to pore opening, had a gas volume fraction after foaming of approx. 30% by volume in >approx. 98% closed inner foam pores. The degree of pore opening (POG) achieved is approx. 18-20%.

Example 4 (see FIG. 12): pore opening by means of (b) cutting/peeling mechanism produced by means of an adjustable cutting device installed at the nozzle outlet end.

Figure 12 shows a foamed, continuously cut strand of extrudate. Open pore structures can be detected on the cut surface. A pore opening degree of approx. 10-15% was achieved in the example shown. The extrudates on which this example is based had about 15-20% gas by volume.

A total volume of open pores of 2-5% is rated as sufficient for enriching the plant protein-based meat analogues described as an example with sensory (aroma, taste) and nutritional (B vitamins, minerals (Fe, Zn)). To increase product juiciness, > 10% is relevant, depending on the water content of the product matrix.

The features described in the patent claims and in the description and evident from the drawing can be essential for the realization of the invention both individually and in any combination. Reference List

aperture housing

metal cylinder

Slot nozzle wall a Aperture inlet flow b »j ,j c a Aperture outlet flow c » »J c

Designations, geometric for the positioning of the metal cylinders

Nozzle housing, conical

Gap adjustment punch, axial

Adjustment plunger guide tube 0 Tempering fluid inlet Tempering fluid outlet Tempering fluid channels a Tempering fluid ducts, inner b Tempering fluid ducts, outer c Tempering fluid ducts in the adjustment stamp Guides Nozzle gap a Nozzle gap in initial position b Narrowed gap setting through the nozzle gap Ring slot nozzles Flange Slot nozzle flow channel Laminar slot nozzle flow Cutting device Extrudate strand a Needle roller, upper b Needle roller, lower Penetration needle conveyor belt dividing device a penetration needle roller pressure dividing device, upperb penetration needle roller pressure dividing device, lower conveyor belt, partially perforated a vacuum half-shell, upper b vacuum half-shell, lower a contact pressure pneumatics, upper b contact pressure pneumatics, lower extrudate part, cut off a Piping for exhaust b Piping for exhaust Partial vacuum storage tank Vacuum pump String cutter Diaphragm pressure transducer 37 diaphragm pressure transducer

38

39 pressure transducer membranes

40 connecting flanges

41 nozzle inlet flow geometry, conical

42 Diaphragm pressure transducer a Angle of rotation of the metal cylinder 2 ß Angle between the center of the metal cylinder and the edges of the cut surface of the

metal cylinder 2 ö angle of rotation of metal cylinder 2

Ri metal cylinder radius

LD nozzle length

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Claims

Foamed, elastic, protein-based product with a dry matter content of 20-60% by weight, a bound water content of 40% by weight and a gas pore structure, the ratio of gas-filled pores (OP) open towards the product surface to gas-filled pores enclosed in the product volume ( GP) is set in the range of 0.05 - 0.95. Product according to Claim 1, characterized in that the product has a protein content of 10 - 95% by weight in its dry matter. Product according to Claim 1 or 2, characterized in that the protein content consists of 0-100% by weight vegetable protein. Product according to Claim 1 or one of the following claims, characterized in that the protein in the product is present in a partially to completely denatured form and has a fibrillar structure. Product according to Claim 4, characterized in that the denatured form has an oriented fibrillar structure. Product according to Claim 1 or one of the following claims, characterized in that the product contains a plant fiber content of 0.5 - 20% by weight, based on the dry substance. Product according to Claim 1 or one of the subsequent claims, characterized in that the product contains a proportion of fats or oils of 0.1 - 15% by weight, based on the dry substance. Product according to Claim 1 or one of the following claims, characterized in that the product contains a proportion of flavoring and/or coloring and/or components which increase the nutritional value in addition to the vegetable fiber proportion of 0.1 - 5% by weight, based on the dry substance. Product according to claim 1 or one of the subsequent claims, characterized in that the product after drying to a residual water content of <5 wt.

54 nem water-containing fluid system, restoring its original

Volume and texture without loss of dry matter. Product according to Claim 1 or one of the following claims, characterized in that the product, after drying to a residual water content of <5% by weight and storage under room temperature conditions for several months without spoilage, in a moisture-controlled manner, when brought into contact with water or a water-containing fluid system, with its original volume being restored and its texture, reconstituted. Process for producing a product according to Claim 1 or one of the following claims, characterized in that the process realizes the opening of gas pores or gas bubbles enclosed in the foamed product towards the product surface in an adjustable manner, with an extrusion process of the "high moisture extrusion cooking" type (High Moisture Extrusion Cooking, HMEC) with gas entry, temporary gas dissolution and controlled gas bubble nucleation as well as foam formation and five process variants for pore opening: (a) opening by rapid ambient pressure drop (flash opening, FOP), (b) opening by dividing or peeling the product (Cut-Opening, COP), (c) Opening by multiple needle penetration (Penetration-Opening, POP), (d) Opening by forced secondary mixed flow (Mix-Opening, MOP) and (e) Opening by freeze structuring (Freeze - Opening, FOP)

55 be applied individually or in combination, whereby the opening of gas pores or gas bubbles enclosed in the foamed product towards the product surface is realized in an adjustable manner. The method according to claim 11, characterized in that the opening of closed pores to the product surface by means of the opening mechanisms (c) by multiple needle penetration (penetration opening, POP) and (e) by freeze structuring after the exit of the partially cooled product from the extruder cooling nozzle, by means the opening mechanisms (a) through a rapid drop in ambient pressure (flash opening, FOP) and (b) through dividing or peeling of the product (CUT opening, COP) in the exit area of the extruder cooling nozzle and the opening mechanism (d) through forced secondary mixed flow (Mix-Opening, MOP) in the extruder cooling nozzle. The method according to claim 11 or 12, characterized in that the opening of closed pores towards the product surface by means of (a) rapid ambient pressure drop (flash opening, FOP) by maintaining the static pressure until just before the nozzle exit at a pressure level of 2 bar by means of an adjustable slot - Nozzle aperture (VSDA), which is installed at the extruder nozzle outlet or just (< 10 cm) in front of it, depending on the viscosity of the exiting fluid mass, to a static pressure prevailing in front of the VSDA in such a way that the inner pores open towards the product surface

56 is given for a likewise product-specifically set proportion of the pores open towards the product surface, based on the total number of closed and open pores. The method according to claim 11 or one of the following claims, characterized in that the opening of closed pores to the product surface by means of (a) pore opening by rapid ambient pressure drop (flash opening, FOP) by abruptly applying a partial vacuum of

100 mbar′ for an extrudate strand section, after it has been cut off, in a quasi-continuously operating vacuum chamber device. Method according to Claim 11 or one of the subsequent claims, characterized in that the opening of closed pores towards the product surface takes place by means of (b) cutting or peeling of the product (CUT-Opening, COP) by the extrudate strand via a slot nozzle in the extruder End built-in cutting device is continuously cut open or its surface layers are peeled off. Method according to claim 11 or one of the following claims, characterized in that the opening of closed pores to the product surface takes place by means of (c) multiple needle penetration (penetration opening, POP) and thereby connecting channels with diameters of 0.1 - 2 mm between internal closed pores or bubbles and the product surface. The method according to claim 11 or one of the following claims, characterized in that the opening of closed pores towards the product surface by means of the mechanism according to the invention of (d) forced secondary mixed flow (mix opening, MOP) takes place, with local cross-sectional constriction of the extruder slot die by means of an adjustable slit-nozzle aperture (VSDA) built into the extruder cooling nozzle via an adjustable slit gap height reduction made with this in the wake of the constriction produced, a roller-shaped secondary flow, which is also adjustable in terms of its intensity and associated mixing efficiency in the direction of the slot height extension of the nozzle gap, is generated, with Alignment of the roller flow rotation axes across the nozzle slot width transverse to the main flow direction. The method of claim 11 or one of the subsequent claims, characterized in that the opening of closed pores to the product surface by means of the inventive mechanism of (d) forced secondary mixed flow (Mix-Opening, MOP) takes place, with viscoelastic aqueous protein melts and other viscoelastic fluid systems by local narrowing of the cross-section of the extruder slot nozzle by means of a built adjustable slit-nozzle aperture (VSDA) in the wake of a constriction made by means of this adjustable narrowing by slit nozzle height reduction, a in its intensity and associated mixing efficiency in the direction of the slit height extension of the nozzle gap so that also adjustable roller-shaped, periodically fluctuating secondary flow is generated, with alignment of the roller flow Rotation axes across the nozzle slot width transverse to the main flow direction, and using an inventive in-line measurement of the amplitude of the sinusoidally oscillating temporal, static pressure profile before or after the VSDA, the degree of intensity of the secondary flow mixing effect is described quantitatively and by adjusting the nozzle slot gap width within the VSDA device is adjusted gradually. The method according to claim 11 or one of the following claims, characterized in that the gap narrowing by adjusting the slot height using the adjustable slot-nozzle aperture (VSDA) according to the invention in accordance with in-line or off-line in a cone-plate shearing gap rheometrically measured viscous and elastic material parameters of the extruded fluid mass takes place under extrusion conditions, with the viscous properties being described by the shear stress T as a function of the shear rate y, the elastic properties by the first normal stress difference Ni as a function of the shear rate y and the narrowing of the slot die gap is carried out in such a way that for the ratio N _X /T below that in the constricted

59 Apparent wall shear rate y _S w prevailing in the slot die gap

relation 2<(Ni/r)<5 holds. Method according to Claim 11 or one of the subsequent claims, characterized in that the in-line measurement of the static pressure profile before or after the VSDA only simplifies the amplitude of the oscillatory fluctuations in the static pressure as a basis for setting the narrowing of the slit gap, the thus in the aperture - Follow-up flow generated secondary flow mixing effect and the associated opening of inner closed foam pores to the slot nozzle wall and thus to the extrudate surface and the generation of new pore channels or gaps open to the product surface. Method according to Claim 11 or one of the following claims, characterized in that the opening of closed pores towards the product surface takes place by means of (e) freeze structuring, with rapid cooling of the product taking place after the extrusion die exit and subsequent cooling treatment in the temperature range between -1 and -20° C, preferably with periodic temperature control, is carried out within these limits.

60 Method according to Claim 11 or one of the subsequent claims, characterized in that the product, after partial pore opening has taken place, is gently dried to a residual water content which allows moisture-controlled product storage at room temperature for several months without microbiological or enzymatic spoilage phenomena occurring. Method according to Claim 11 or one of the following claims, characterized in that the product is reconstituted by water or fluid absorption after partial opening of the pores and gentle drying to a residual water content which allows moisture-controlled product storage at room temperature for several months. Method according to Claim 1 or one of the subsequent claims, characterized in that the degree of pore opening for values 0.1 is set with an accuracy of +/- 0.05. Method according to Claim 1 or any subsequent claims, characterized in that the gas volume fraction (= porosity) is also set between 0.1 and 0.8 with an accuracy of +/- 0.05.

61 Device for carrying out the method according to Claim 11 or one of the following claims, characterized in that the extrusion nozzle is followed by a cutting device (33) and a conveyor belt (26) partially perforated in the middle in sections of the cooling nozzle of an HMEC foaming extruder and the conveyor belt (26) with the cut-off part of the product lying on top is guided between two vacuum half-shells (27a, 27b) which, pressing against each other from above and below, enclose the conveyor belt (26) and the product in a sealed manner, and these vacuum half-shells are used for the sudden application of a partial vacuum to the foamed , extruded product are connected to a vacuum storage tank (31) via a vacuum line provided with a quick opening valve and this is connected to a vacuum pump. Device according to claim 26, characterized in that in the extruder nozzle outlet, embedded in the slot nozzle channel to ensure product strand guidance, cutting knives with a small blade width of 2 mm or thin cutting wires or water jet or laser cutting devices are arranged in such a way that either (i) cutting or peeling off of the surface layers with a layer thickness of <1 mm or (ii) the product strand is divided in the middle in the slot height direction.

62 Device according to claim 26 or 27, characterized in that at the nozzle outlet two rotatably suspended needle rollers (22a, 22b) equipped with solid needles with barbs - felting needles - or hollow needles with needle diameters between 0.3 - 5 mm are arranged, between which the strip-like extruded datstrang (21) formed extruded product is guided and the needle penetration depth is set to between 1-20 mm, depending on the product shape, and the puncture number density is set to between 1-49/cm ² . Device according to Claim 26 or one of the following claims, characterized in that a slot nozzle aperture (VSDA) adjustable in the gap width between 10-100% of the slot channel height of the extrusion nozzle in case (A) purely viscous flow properties of the non-solid or partially solidified Fluid system between 10-50% of the nozzle length before the nozzle end of the cooled extruder slot die and in case (B) viscoelastic flow properties of the non-solid or partially solidified fluid system between 5-95% of the nozzle length before the nozzle end of the cooled extruder slot die or directly at the nozzle end. Device according to Claim 26 or one of the following claims, characterized in that the slot nozzle aperture (VSDA), which can be adjusted in the gap width between 10-100% of the slot channel height of the extrusion nozzle, in its 100% open state exactly the dimensions of the free extruder slot nozzle cross-section and for the case of a present flat, rectangular

63 angled extruder nozzle slot channel in the upper and lower wall delimiting the flow slot of the aperture device over the entire slot width, at right angles to the direction of flow, a cut, rotatably slide-mounted metal cylinder is sealingly embedded in each case, with the cut surfaces of these cylinders being flush with the flow channel wall when the aperture is fully open, as well as when the cylinders are rotated externally by hand or by means of a servomotor, an adjustable narrowing of the aperture occurs on one side or symmetrically to the longitudinal axis of the nozzle, which corresponds to the maximum degree of closure of the slot channel at a twist angle of 90°. Apparatus according to claim 26 or one of the following claims, characterized in that the slot nozzle aperture (VSDA) used, which can be adjusted in the gap width between 10- 100% of the slot channel height of the extrusion nozzle, in its 100% open state exactly the dimensions of the free extru - corresponds to the slit nozzle cross-section and, in the case of an extruder nozzle with an annular gap for higher throughput rates, a piston-like ram with a conical attachment is arranged to narrow the annular slit gap in such a way that its defined axial insertion, preferably by means of a servomotor, into the for adapting the extruder annular slit nozzle conically designed extruder outlet nozzle defines a defined narrowing of the annular slot gap.

64 Device according to Claim 26 or one of the following claims, characterized in that the extruder cooling nozzle and the extruder nozzle inlet are equipped according to the invention with 4-5 sensors (P1-P4, P5) for static pressure measurement, with one of the sensors (P1) preferably being flush with the wall in front of the extruder nozzle inlet and three of the sensors (P2-P4) in the extruder slot die, of which two (P2, P3) are flush with the wall in front of the slot channel constriction set using VSAD and one (P4) is also flush with the wall directly in the outlet flow of this slot channel constriction, and in the case of viscoelastic fluid properties an additional one fifth sensor for static pressure measurement (P5) directly opposite sensor P2 on the opposite side of the slotted duct, but not flush with the wall, but placed in a cavity (43) inserted in the bottom of the slotted duct nozzle, and this cavity forms a cuboid bulge of the slotted nozzle with a rectangular cross-section , preferably in the Has dimension ranges (1-1 .5) x (4-6) cm and a depth of 3-6 cm. Device according to Claim 26 or one of the following claims, characterized in that the sensors for static pressure measurement P1 to P3 for the in-line detection of apparent extensional and shear viscosities in the nozzle inlet flow are integrated flush with the wall in the flat slot flow channel, as are the sensors for static pressure measurement P2 and P5 to determine an elastic normal stress difference proportional pressure difference in the flow channel height direction orthogonal to the flow direction and directly opposite each other, P2 flush with the wall in the flow channel, P5 not flush with the wall, other

65 which are installed on the bottom of a cavity with a rectangular cross-section and the sensor P4 for measuring the oscillatory pressure fluctuations caused by the secondary flow, flush with the wall and in flow direction after the adjustable slot nozzle aperture (VSDA), is integrated in the flow channel. Device according to Claim 26 or one of the subsequent claims, characterized in that the extruder nozzle outlet is connected to a cooling immersion bath for cooling the extrudate strand to below -20°C, preferably to below -50°C, and, according to the invention, two freezing chambers are connected downstream for periodic - 1 -2 h period duration - product rearrangement, these freezing chambers being set to constant -1 °C and -20 °C. Use of the product according to claim 26 or one of the following claims, characterized in that the resulting foamed product with an adjusted degree of pore opening is used as a structured basic element for meat analogues, the proteins used being only of vegetable origin and such meat analogue basic elements being used in menus which bring about a gradual to complete filling of the open pores of the structured basic element through complemented, fluid sauce or juice or dressing or marinade or topping components.

66 Use according to claim 35, characterized in that the product is used as a component in cheese, confectionery, baked goods, waffles and chocolate confectionery.

67