CN116963606A

CN116963606A - Foamed elastic protein-based product, method for producing such a product, in particular an extruded meat-like product based on vegetable proteins and vegetable fibers, device for carrying out such a method, and use of the product for producing a meat-like product based on vegetable proteins

Info

Publication number: CN116963606A
Application number: CN202180093327.6A
Authority: CN
Inventors: E·温德哈伯; J·津克; C·萨克斯
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: 2023-10-27

Abstract

The invention relates to a product with a foam structure, which has a regulated proportion of open pores towards the surface of the product up to closed pores. The invention also relates to a method with four embodiments according to the invention for defined mechanical opening of closed foam cells. The invention further relates to a device with four embodiments according to the invention for defined mechanical opening of closed foam cells. The invention also relates to the use of the product designed according to the invention as a meat analogue product or a textured multiphase food based on vegetable proteins, in particular a vegetable or fruit composite. Particular advantages of the invention relate to the targeted influence of the deformation and texture properties of the foamed products, as well as their accessibility from the outside, for simple and rapid filling of open cells with fluid systems, which introduce additional functions into the products.

Description

Foamed elastic protein-based product, method for producing such a product, in particular an extruded meat-like product based on vegetable proteins and vegetable fibers, device for carrying out such a method, and use of the product for producing a meat-like product based on vegetable proteins

Technical Field

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

In addition, the invention relates to a method for producing such a product, which has a defined degree of perforation which is regulated.

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 a main component for the preparation of vegetable protein-based meat-like products.

Background

The viscous material can be foamed in the extruder by: the gas is metered, mixed/dispersed at atmospheric or overpressure and/or partially until completely dissolved at overpressure and then released again by pressure relief and kept partially until completely incorporated into the viscous material to form foam/1, 2/.

Another known possibility is to add foaming agents which, as a result of chemical/physicochemical and/or thermal reactions, form a gas which is also partly until completely incorporated into the viscous material by means of a mixing/dispersing process, forming a foam. The corresponding viscous materials may be synthetic and/or biological in nature or may also consist of mixtures thereof and may be binders or components of products in the food, cosmetic, pharmaceutical, construction or plastics industries. In the extruder, viscous material foamed in this way is conveyed by the extruder screw and is pressed through the extruder nozzle. Due to the narrowing of the flow cross section at the transition from the extruder housing to the extruder nozzle, a static pressure build-up occurs here, which in the nozzle, with the nozzle cross section remaining more or less constant, is reduced again to atmospheric pressure at the extruder nozzle outlet by the flow shear stresses prevailing here due to wall friction and internal fluid friction. The pressure build-up in the nozzle inlet region (prior to entering the nozzle) compresses the gas trapped in the foam bubbles and thus reduces the size of the foam bubbles, reducing the pressure in the extruder nozzle to outlet atmospheric pressure allows the gas in the foam bubbles to re-expand and thus increases the foam bubbles. Larger bubbles may deform in the nozzle flow compared to smaller bubbles at lower flow stresses, and if critical stresses are exceeded they may collapse and thus be converted into smaller bubbles.

In general, the aim is to have a strand of material of a defined shape discharged from the extruder nozzle, since the product shaping is also usually carried out by means of the extruder nozzle. The dimensional accuracy of such products is often an important quality measure as well. This is achieved in particular by achieving a uniform laminar flow in the nozzle, which corresponds to a planar laminar flow. If a foamed fluid system is moved in such a nozzle flow, the shear of the fluid system at the nozzle wall increases due to the typical parabolic flow profile, whereas no shear occurs in the center of the nozzle channel. The fluid systems flowing in this way do not cross-mix (parallel stratification) provided that the nozzle channels do not have any flow obstruction. The maximum wall shear rate present in the fluid layer in contact with the wall (=the velocity of the fluid film near the wall in question on its side facing the centre of the nozzle channel divided by the fluid film thickness) generally leads to the formation of a boundary layer near the wall. If the fluid system contains dispersed components, these will be put in rotation due to the effective wall shear velocity in the fluid layer in question near the wall and undergo dynamic buoyancy (lift), which causes the dispersed components to separate from the wall away towards the centre of the nozzle channel. This applies in principle to solid particles/3/, but also to bubbles/4/, and leads to depletion of the fluid layer close to the wall with such dispersed components.

The "High Moisture Extrusion Cooking (HMEC)" method is preferably used to extrude vegetable protein based meat analog products. This process involves extrusion at high temperature (up to about 170 ℃) and high static pressure (up to about 100 bar), with a water content of the product of up to about 70% by weight. In aqueous protein melts prepared under these conditions, protein denaturation occurs in the form of protein fibrils which, due to the effective elongational flow component there, are oriented in the direction of flow in the extruder nozzle inlet flow and solidify in this oriented structural state by subsequent cooling (to about 60 ℃) in a long (. Gtoreq.about.1 m) extruder cooling nozzle. In the case of a typical laminar nozzle flow, the cooled product exits the extruder nozzle as a smooth strand. The oriented protein fibrils impart a meat-like fibrous texture/5/-to the product. Due to the slow cooling of the product in the extruder nozzle, sudden pressure relief of the water vapour is suppressed and thus the formation of the structure is not disturbed.

The prior art regarding HMEC extrusion processes for the preparation of vegetable protein based meat analog products is for example fully described in patent documents US6,635,301B1, WO2016/150834A1, EP1182937A4, WO2009075135, US20050003071A1, WO2016150834A1 and US10,716,319B2.

US10,716,319B2 (method of making structured protein composition) is considered from a technical point of view to be the closest description to the technology according to the invention described in this patent application (closest to the prior art): (summary translation of US10,716,319B2): "the fiber composition obtained in the extruder exits the extruder at a temperature of the composition above the boiling temperature of the available water (e.g., 100 ℃ at atmospheric pressure or lower if a vacuum port is used). This is believed to result in expansion and subsequent collapse of the textured product. Further, it is believed that the expansion/collapse process interferes with the fiber orientation and thus results in a more random orientation of the formed fibers. Furthermore, it is assumed that air entrainment (on both microscopic and macroscopic scales) is formed in the textured product. In order to fine tune the mouthfeel (bite), tenderness and juiciness, after the texturing process, the extruded product may be hydrated in an aqueous liquid at elevated temperature (i.e. between 40 and 150 ℃) until a final moisture content of 50 to 95% is reached. The cutting test is most commonly used to measure the tenderness of the extrudate, for example using a Warner Bratzler shearing blade// or a Kramer shearing unit//. 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 advantageous because absorption of the aqueous liquid makes it easier to add the desired flavour components and makes it possible to modify the product in terms of juiciness and bite. Infusion into the extrudate according to the invention is carried out into the wet 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 55 to 70 wt%. The structured vegetable protein composition resulting from infusion with an aqueous fluid preferably has a water content of 70 to 90 wt%. Surprisingly, if the extrudate is first frozen (and then thawed prior to infusion), the infusion described above can be improved by an aqueous liquid (i.e., faster drainage and/or allowing more water to be incorporated). Preferably, the freezing temperature is below-5 ℃ and-15 ℃. "

Microfoaming of high-viscosity and viscoelastic, dough-like, protein-based and non-protein materials by means of extrusion processes is described in WO 2017/081271 A1.

The state of knowledge in food foam systems is described, for example, in the following documents: peter j. Hailing&Pieter Walstra (1981) Protein-stabilized foams and emulsions (Protein stabilized foam and emulsion), C R C Critical Reviews in Food Science and Nutrition,15:2,155203, DQI:10.1080/1040839810952 7315and Ashley J. Wilson (1989) Foams:Physics, chemistry and StrStructure; springer Verlag London, ISBN 978-1-4471-3809-9.

The preparation of open-cell foams is known in the plastics/foam industry (N.Mills (2007); polymer Foams Handbook (handbook of Polymer foam); finishing ISBN:9780750680691; version description: butterworth-Heinemann).

Conventional extrusion processes, in particular retort extrusion processes, in the field of food, construction materials and animal feed applications, produce holes which are only within wide limits and are not reproducible due to the sudden evaporation of water/solvent at the extruder nozzle outlet. The product (extrudate) here undergoes the formation of a foam-like structure, which is obtained by the sudden evaporation of water due to the pressure drop.

In newer extrusion/retort extrusion processes, the foamed product can also lead to a product with better control in the foam structure by means of gas metering and gas dispersion or gas dissolution and re-nucleation of bubbles. However, these products typically have closed cells and when they flow through the extruder nozzle, a skin layer is formed that is substantially free of foam bubbles and cells due to the maximum shear forces near the wall.

For foam extrusion applications, the foam cell structure must be controlled significantly in order to adjust the product properties so that the ratio of closed cells to open cells can be adjusted.

In certain applications, such as in ready-to-eat products, the open pores allow the liquid to be desirably rapidly absorbed by capillary forces, closed pores being desirable when setting the lowest possible product density, achieving a foamy/creamy mouthfeel (food) or reducing the rate of absorption of the fluid (foam bubbles acting as a mass transfer barrier).

For a range of products from different application areas, the adjustability of the ratio of closed cells to open cells is important for the appearance of certain quality features. Typical examples for this are fish feed pellets, which are accepted by certain fish in terms of their sinking rate or their swimming behaviour, which usually accept their fish feed from the bottom of the body of water (from floating at a certain water depth or swimming from the surface).

Up to now, there is no industrially relevant solution for food products with a high content of bound water, such as vegetable protein based meat-like products with up to >60% intermolecular water formation, in order to optimize such products on the one hand in terms of their consistency and thus texture organoleptic aspects by defined adjustable (i) micro-foam formation and (ii) ratio of open to closed foam cells, and on the other hand to achieve adjustable additional, especially rapid (in the range of seconds) fluid absorption capacity in connection with preparation, optimizing e.g. juiciness and certain further handling properties during e.g. frying/grilling, as well as taste/aroma and nutritional functionality.

From KR 1020200140499A it is known to prepare foam structures in which random gaseous inclusions are generated. It has also been proposed to influence the change in the gaseous inclusion layer and its shape by means of a change in the empirical formulation, but this cannot be done in a targeted manner. A random porous structure is created at the extruder nozzle outlet, which is hardly affected by the process technology, since an uncontrolled rapid expansion is involved. If long chain elastic gluten molecules are present, this vapor expansion is more and more counteracted, resulting in a product with a lower degree of expansion. The preparation of such process technology uncontrolled porous extrudate products is transferred to gluten-containing meat analog products.

It is known from 2020/0060310 A1 to form porous structures by "puffing". This is understood to mean abrupt expansion, which is not sufficiently controlled with respect to the porosity produced and, of course, is not properly controlled with respect to the defined cell size.

Disclosure of Invention

Purpose(s)

The invention was initially based on the object of producing a foamed product with a high bound water fraction, which in the case of extruded meat-like products has a vegetable protein fraction of > 30% by weight and a vegetable fiber fraction of > 5% by weight based on the concentrated vegetable protein melt and a gas volume fraction of > 10% by volume in the final product, wherein the gas volume is present in the form of pores/bubbles which should be present in a proportion which can be adjusted as pores opening towards the surface of the product in order to ensure that, for example, accelerated further liquids are absorbed into the product with sensory and/or nutrition-related components contained in such liquids.

In addition, the present invention is based on the object of providing a process which can be used for preparing such products.

The invention is based on the object of providing a corresponding device which enables the method to be carried out.

Finally, a further object is the use of such a product, for example for the preparation of vegetable protein based meat-like products/meat substitutes.

Implementation of objects relating to products

This object is achieved by the features of claim 1.

Some advantages are

The new foamed products according to the invention allow to couple the regulation of specific organoleptic and nutritional properties by regulating the foam cell size as "intrinsic" properties of these products, which is currently not possible with conventional products of this type or can only be achieved to a small extent by adding products (sauces, toppings, etc.). In the case of foamed vegetable protein-based meat-like products, it is thus possible to provide in a matchable adjustment manner by enabling or improving the cooking, frying and grilling capabilities (a) the organoleptic quality attributes decisive for the consumer: tenderness, juiciness, crispiness, meat flavor/aroma, (B) nutritional functions (e.g., by the incorporation of bioavailable iron and B vitamins) and (c) convenience.

The formation of foam structures in high viscosity to semi-solid products has a significant impact on their mechanical behavior in the direction of the more deformable/softer material. In the case of such products in the food field, such as those represented by extruded, foamed vegetable protein-based meat-like products, one may find a less compact, hard or "tender" consistency due to foaming. In the case of (a) closed cell foam systems, the compressibility of the gas enclosed in the cells contributes to the deformation behavior of the foam product. When the deforming force is removed, the reverse expansion of the gas enclosed in the hole supports elastic reverse deformation and is even dominant at high gas volume fractions. In the case of (B) open-cell foam, the gas in the cells can escape more or less rapidly, depending on the cell size, when the foam matrix is deformed. Thus, the deformation behaviour of the matrix material forming the foam lamina dominates the macroscopic deformation behaviour of the foam product.

In the case of foamed foods, which undergo significant deformation upon consumption due to biting and chewing, the closed foam cell structure (a) enhances the sensory texture impression (i) tenderness (softness), and also (ii) rubbery tackiness (gum) in the case of solid structures of the foam lamina surrounding the bubbles, and (iii) creaminess in the case of fluid foam lamina properties.

The open-celled, spongy foam structure (B) allows the organoleptic texture attributes (iv) crispness, but also (v) crispness to be noted in the case of thin solid foam layers. The case of fluid foam lamina properties is not important in the case of open cell product systems, as deliquescence of the matrix material can result in a foam having closed cells.

In the case of a defined foamed matrix of vegetable protein-based meat-like products, which has a solid structure of a thin layer of foam surrounding air bubbles, consumer expectations/consumer ideas particularly suggest that the fibrous properties combined with tenderness (softness) are taken as organoleptic texture properties, and that the juiciness and crispiness/bite/crispiness are taken as other important properties, often also in connection with certain cooking methods (e.g. boiling, frying, broiling).

In the case of such foamed meat analogue products having at least partially open cells, their organoleptic, nutritional and cooking convenience related properties may be significantly extended, as the cells of the foamed base product are partially or completely filled with a functional or functionalizing fluid, wherein such fluid may also solidify after cell filling. By such "fluid filling" of the open cell meat analogue product, the organoleptic and/or even nutritional product properties associated with specific tastes and aromas, and possibly the product stability, may be optimized by preservative components.

For example, the filling of the openings can take place by capillary forces which, in the case of matched wetting properties of the filling fluid, allow the fluid to be sucked in as a result of the formation of a capillary vacuum. Since this capillary force is inversely proportional to the pore diameter, a pore diameter in the range of about 500 microns or less is preferred.

The subject of the present invention is based on the HMEC technology as described above for the preferred preparation of vegetable protein based meat analogue products, wherein the technology is significantly supplemented by a combination with a micro-foaming process which takes place in an extruder and is described in a comparable manner in relation to the preparation of foamed baked goods/2/in. In this case, the amount of gas metered in (e.g. N ₂ ，CO ₂ ) First in the extruder, at the high pressure set there, dissolved in the aqueous protein melt and then depressurized again in the extruder cooling nozzle with a pressure drop. In the method, the bubbles nucleate at the start of the extruder nozzle and become larger in the further advance of the nozzle flow with a sustained release of pressure, thereby forming a foam structure.

Furthermore, the description of the subject matter of the present invention is based on the availability of this foaming technique and its applicability to the preparation of meat-like products produced by HMEC technique, foamed in this way. The product-related emphasis of the subject matter of the invention described below is a vegetable protein-based (foamed) meat-like product that provides innovative tuning options for sensory and nutritional product characteristics with important consumer relevance by the adjustability of the ratio of closed pores/open pores/pore channels towards the product surface.

The close-wall cooling of the product stream exiting the HMEC extruder at the inlet into the extruder nozzle, which starts during the preparation of the meat analogue product, allows the high pressure still prevailing there and in case the temperature near the nozzle wall has been significantly reduced (from typically about 140-160 ℃ to about 90 ℃) fewer foam bubbles are formed near the nozzle wall due to the improved gas solubility at lower temperatures.

In addition to the above-described effect of (ii) improved gas solubility, (i) the high shear of the cooled foamed protein melt in the vicinity of the nozzle wall also supports (iii) bubble depletion by the flow effect (dynamic buoyancy) in the region of the nozzle wall. The "skin layer" of the extruded foamed meat analog product strand, which is thereby partially or completely depleted of air bubbles, protects the inner foam cells from the environment. Since the product is typically cooled slowly in the long cooling extruder nozzle used in the extrusion of meat-like product HMEC, there is no longer a significant residual pressure release at the nozzle outlet, so the product skin layer formed remains closed. For a micro-foamed product this means that a closed foam cell system is present.

For most applications or end product forms, it is advantageous to create an open sponge-like pore system that is capable of absorbing liquid into a porous (sponge-like) product matrix through the outwardly open pores. The fluid absorbed in this form may interact with the matrix structure, maintain fluid characteristics or solidify or partially solidify under the frame conditions (e.g., temperature) to be conditioned. For example, food systems equipped with such open cell porosities can absorb liquids that impart juiciness to the associated food product. Suitable fluid systems for impregnation may lead to improved resistance to mold/fungus attack or pests in order to construct building materials with corresponding pore structures. For application in wound healing, a porous structured cover material with corresponding openings may be impregnated with a fluid for disinfection or a fluid component that promotes wound healing.

In this context, there is a great interest, depending on the application, in adjusting the cell structure of the product system foamed in the extrusion process in a targeted manner.

The subject of the present invention is therefore a technique for adjusting the ratio of closed cells/bubbles to open cells/cell channels open towards the surface of the product. In principle, this can also be achieved mechanically by connecting the initially closed foam bubbles/pores, provided that these can coalesce or form connecting channels between them and at the product surface in a defined manner without significant loss of the total gas volume fraction and the fine porosity.

According to the invention, the pore volume ratio e=epsilon, which can be adjusted by means of various specific measures _OP /ε(ε _OP Porosity of open cell; epsilon = total porosity) are implemented in their individual or coupled applications. POT according to the present invention _i Can be found in table 1 and described in detail below.

POT-1：

The slit nozzle orifice (VSDA) adjustable in gap width according to the invention is arranged adjacent to or at the end of the optionally shortened extruder slit nozzle and narrows to a position that allows the static pressure to be adjusted to a value of ≡1.5-2 bar before entering the narrowed slit gap, said value of about 1.5-2 bar being the value of the static pressure prevailing after leaving the slit gap, which is typically atmospheric pressure. With this process according to the invention, the extrudate strands are not cut directly at the nozzle outlet, but only from a length of 5-10 cm. Whereby the shorter length distance between the centre of the extruded strand and its surface is about +.1/2-1/6 compared to the length of the extruded product strand up to the strand cutting device. According to the invention, this results in a release of the preferred gas pressure in the direction of the product cross section and thus towards the product surface. This is due to the significantly larger pressure gradient achieved in this direction compared to the pressure gradient prevailing in the length direction of the strand. The characteristics of the orifice channels formed in the direction of pressure relief and their opening out to the surface of the extruded strand are determined to a large extent by the rheological properties of the extruded product as it exits the extruder nozzle. The lower viscosity (or elasticity) allows for more pronounced material deformation under the influence of the pressure release gradient and thus allows for more pronounced formation of the pore channel.

The design of the geometry of the adjustable slit nozzle arrangements (VSDA) according to the invention enables to achieve flow cross section profiles with different geometric shaping in the flow direction. According to the invention, the narrowing is preferably abrupt (about 90 °) which forces a secondary flow of the extrusion line fluid in the region of the widened flow channel cross section again. In this subsequent secondary flow region, the static pressure is significantly reduced and, on the other hand, a roller-shaped secondary flow is produced, which results in a mixing of the strand fluid transversely to its flow direction in the height direction of the slot nozzle channel. The "inside-out turn" of the extruded strand material depends on the intensity of the secondary flow and its rotational frequency. Because the strand material is located either adjacent to or directly in front of the nozzle outlet, it is not possible to reform a closed skin layer on the product strand, which can lead to a renewed aperture closure. This results in the formation of retained holes/hole channels that are open to the surface of the extruded strand.

The product according to the invention, which is prepared by the method according to the invention using the device according to the invention, makes it possible to obtain a novel extruded product with a defined regulated foam structure. These products form the practically relevant foundation for new product development:

(a) With an adjusted volume ratio of open and closed cells (open cell, POG),

(b) No skin/edge layer formation occurs when flowing through the extruder nozzle

(c) Has adjustable texture characteristics (tenderness, crispness, and juiciness)

(d) With the possibility of an optimization of the flavour/aroma/active ingredient by means of the fluid system absorbed into the openings, which contains the corresponding flavour, aroma or active ingredient components which do not penetrate the extrusion process, thus avoiding their reduction in functionality and accelerating their release through the open pore channels upon application (consumption and digestion of food, ingestion of drugs).

(e) There is an extended possibility of "ready-to-eat product" preparation, which allows for accelerated wetting and dispersion in liquids.

Other embodiments of the invention

Other embodiments of the invention are described in claims 2 to 10.

Claims 2 to 5 emphasize the important role of protein fraction and modified denatured, optionally anisotropically formed protein structure, as the meat-like texture properties of the preferred contemplated meat-like product are significantly attributed to denatured fibrillar protein structure.

To this end, claim 2 describes a product wherein the protein fraction is 10-95% by weight in its dry matter, and claim 3 describes a product wherein the protein fraction comprises 0-100% by weight of vegetable proteins.

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

Claims 6 to 8 contemplate ingredients and their amounts, which are particularly important for regulating the organoleptic and nutritional aspects of the corresponding strictly vegetarian meat-like product.

To this end, the product of claim 6 comprises a plant fiber fraction of 0.5 to 20% by weight on a dry matter basis.

A product is described in claim 7, wherein the product comprises a fraction of fat or oil of 0.1-15% by weight on a dry matter basis, whereas the product in claim 8 is characterized by comprising flavouring and/or colouring components and/or components that increase the nutritional value in addition to the vegetable fibre fraction in a proportion of 0.1-5% by weight on a dry matter basis.

Claims 9 and 10 solve the surprisingly found special features of foamed products according to the invention with cell fraction, which represent their volume, shape, structure and texture-related reconfigurability after almost complete drying. The effect of the degree of perforation has a significant effect on accelerating the output of water from or into the wet product during both drying and reconstitution.

To this end, claim 9 proposes a product which, after drying to a residual water content of < 5% by weight and after storage for several months under humidity-controlled conditions without spoilage at room temperature, is reconstituted to regain its original volume and its texture when contacted with water or an aqueous fluid system, without losing dry matter.

In this connection, claim 10 describes a product which, after drying to a residual water content of < 5% by weight and after storage for several months under humidity-controlled conditions without spoilage at room temperature, is reconstituted to regain its original volume and its texture when contacted with water or an aqueous fluid system.

Implementation of the object concerning the method

This object is achieved by claim 11, characterized in that the method achieves in an adjustable manner the opening of cells or bubbles enclosed in the foamed product towards the product surface, wherein the extrusion method is based on "high-moisture extrusion cooking" (high-moisture extrusion cooking, HMEC), wherein there is gas ingress, temporary gas dissolution and controlled bubble nucleation and foam formation, and the following five method variants are employed individually or in combination for opening the pores: opening (rapid opening, FOP) by rapid drop of ambient pressure, (b) opening (cut opening, COP) by separation or peeling of the product, (c) opening by multiple needle puncture (puncture opening, POP), (d) opening by forced secondary mixed flow (mixed opening, MOP) and (e) opening by freeze structuring (freeze-open, FOP), whereby opening of cells or bubbles enclosed in the foamed product towards the product surface is achieved in an adjustable manner.

Some advantages are

The method according to the invention and its design can be coupled directly to the HMEC extrusion method and can be transferred directly to the extrusion parameters to be set for structuring the protein matrix for opening. Thus, for (a) the mechanism of opening holes by a rapid drop in ambient pressure (fast-open, FOP), the static pressure built up in the extruder can be maintained up to the end of the nozzle, so that a sufficiently fast and efficient residual pressure release for opening holes can be achieved. In the case of mechanisms (b) for opening by separating or peeling the product (cut-open, COP) and (c) for opening by multiple needle penetration (puncture open, POP), the movement or kinetic energy of the extrudate strand at the nozzle tip is used for cutting/peeling or for needle penetration. To activate the mechanism (d) of opening holes by forcing the secondary mixed flow (mix open, MOP)), a portion of the moving flow of the extrudate strands can be used to create an additional periodically oscillating secondary flow for the viscoelastic material in the form of a roll, which results in mixing transverse to the flow in the height direction of the extruder slot nozzle, which thus lengthens the closed foam cells, moves them towards the surface of the strands, and "tears" the surface structure at a strength that can be adjusted so that a portion of the correspondingly treated cells (which can also be adjusted) open towards the product surface. The adjustability of the opening degree is based here on the adjustability of the intensity of the mixed secondary flow, which in turn can be adjusted within wide limits by adjusting the partial slit nozzle height reduction and the conveying speed of the extrudate strands. According to the invention, the mechanism (e) of opening cells by freeze structuring is applied to the foam structure so that at a preferably slow freezing rate mainly large ice crystals pierce the intermediate walls of the material between the closed cells and thus convert them into open cells. Preferably considered are vegetable protein based meat analog products whose high moisture content (up to 60% by weight or less) helps to support ice crystal formation.

Other embodiments of the invention

Other embodiments of the invention are described in claims 12 to 25.

According to claims 12 to 21, the pore opening methods are specified in terms of their technical implementation of the method, by means of the following mechanism (a) the activation of a compressive force to break the pore boundaries outwards towards the product surface; (b) Exposing the hole openings with a targeted incision, (c) creating a connecting channel between the closed product holes and out to the product surface by needle penetration, (d) involving creating a secondary flow in the extruder cooling nozzle forBreaking the mostly closed product skin created in laminar slot nozzle flow by cross-mixing in the direction of the height coordinates of the nozzle channels and creating additional surface transverse channels/transverse grooves. For a preferentially addressed protein-rich meat analogue product system, the additional flow dynamics of the viscoelastic fluid system may be advantageously exploited according to the present invention. The so-called elastic turbulence effect (sometimes also referred to as "melt fracture phenomenon" in the literature relating to plastic processing) is due to the elastic deformation energy storage in the inlet flow convergence of a slit-nozzle orifice (VSDA) device designed according to the invention and arranged in a defined manner in the nozzle channel, being adjustable with respect to the slit channel narrowing. In the narrowed discrete outlet flow, the previously stored elastic tensile stress is again partially relaxed by elastic reverse deformation of the viscoelastic fluid (e.g., corresponding to the protein melt of the HMEC extruded meat analog product). The small flow asymmetry or random variance of the elastic deformation results in a roll-like flow disturbance that forms periodic sinusoidal oscillations. As surprisingly shown on the basis of rheological laboratory measurements of a large number of polymer melts, the above-mentioned secondary flow phenomenon is reflected in a first normal stress difference N ₁ The ratio of the shear stress tau is from N ₁ The value of τ is greater than or equal to 1.5-2, and is N ₁ The range of/τ≡4-5 is particularly effective in order to make effective use of the described inventive effect of sinusoidal oscillating secondary mixing flow (OSMS) after narrowing of the local slit nozzle gap for cross-mixing in the extruder nozzle for opening the holes towards the product surface. The OSMS can thus be adjusted to 2. Ltoreq.τ _W /N ₁ <5 in the intensity to which it relates according to the method of the invention. τ _W And N ₁ The method can be used for measuring the shear gap of the conical plate in rheological laboratory measurement and can also be used for measuring the rheological measurement of the high-pressure capillary. The latter is also directly transferred to the in-line measurement in the extruder slit nozzle according to the invention. According to the invention, this is done by means of static pressure profile measurements in the nozzle channel before and after the partial slit nozzle height reduction or in the extruder side nozzle inlet zone. According to the inventionIn a simplified manner, the intensity of the OSMS is measured via the magnitude of the static pressure fluctuations in the slit nozzle passage before or after the local slit nozzle height is reduced. The adjustment of the maximum elastic turbulence OSMS for local slit nozzle height reduction by means of the adjustable orifice according to the invention may be limited by the fact that: excessive fragmentation of the product strand at the outlet of the nozzle is to be avoided. This is achieved by the adjustable slit nozzle orifice (VSDA) device according to the present invention being typically installed in the first two thirds of the extruder cooling nozzle length. In this way, in the laminar flow restored after the orifice, the elastically turbulent mixed product strand is again partially smoothed in a defined manner and, if necessary, the crack formation in the structure gradually heals again. In order to avoid the re-formation of the skin layer of the product strand, which has an associated hole closure towards the product surface, the degree of OSMS adjustable by the VSDA as described and the length of the extruder nozzle downstream of the orifice are adapted according to the invention or calibrated according to the specific material system.

Claims 22 and 23 refer to the possibility of drying the product after having been perforated according to any one or a combination of methods (a) - (e) in order in this way to achieve an extended shelf life at ambient temperature storage. According to the invention, the opening of the holes advantageously accelerates the transport of water during drying and during reconstitution.

According to claims 24 and 25, basic conditions are specified for adjusting the degree of opening in the product and the accuracy of the total pore volume as a basis, which product should have or be provided with an open connection to the surface of the product. The resulting bandwidth from (i) through (ii): (i) A total gas fraction (in the form of pores) of at least 10% by volume, wherein 5% is open, (ii) a total gas fraction (in the form of pores) of at most 80% by volume, wherein 90% is open, which is important for e.g. foamed meat-like products in order to achieve an easy penetration of strongly flavoured substances e.g. in fluid form in case (i) and a uniform penetration of e.g. 72% of the product volume with a fluid phase imparting a consistency/texture, optionally solidified after pore filling. In the latter case, when applied to meat-like products, a scaffold protein structure is obtained, having e.g. pie/sausage fillings of a strictly vegetarian person. Within the range between (i) and (ii), a "marble-like" product structure with a fat/gel insert tailored to further tailor the typical meat/fat/connective tissue/gel structure and related organoleptically preferred textural properties can be achieved.

According to claim 25, the aerated volume fraction is limited to 80% by volume, because the cell opening mechanism according to the invention associated with very firm (fest) foam products is not sufficient to be transferred nondestructively to the whole product if the foam is too brittle.

Implementation of the object concerning the device

This object is achieved by claim 26, characterized in that the extrusion nozzle has a downstream cutting device and a downstream conveyor belt, which is partly perforated in the middle of the cross section of the cooling nozzle of the HMEC foaming extruder, and that the conveyor belt together with the cut-out portion of the product placed above is guided between two evacuating half-shells, which close the conveyor belt and the product in a closed manner from above and below in a pressed manner against each other, and in that these evacuating half-shells are connected to a vacuum reservoir via a vacuum line provided with a quick-opening valve and to a vacuum pump in order to apply a partial vacuum to the foamed extruded product.

The cell opening mechanism uses mechanical, fluid mechanical or thermodynamic principles of action, opening closed cells towards the product surface by means of the following device variants:

(a) A device variant for regulating a rapid drop in ambient pressure (quick-open, FOP),

(b) A device variant (cut open, COP) for separating or stripping the product in the outlet region of the extruder cooling nozzle,

(c) A device variant for multiple needle piercing (piercing open, POP),

(d) A device variant (mix open, MOP) for producing a secondary mixed stream in the extruder cooling nozzle.

(e) Device variants (freeze-open, FOP) for producing large ice crystals for foam sheet puncture by means of freeze structuring in post-treatment for quench cooling after the extruder cooling nozzle outlet, which can be used in single or combined applications.

The core element of the device for activating the aperture mechanism according to (a) and (d) is an adjustable slit nozzle orifice (VSDA). When it is in the 100% open state, its free cross-sectional area for the passage of the extrudate corresponds exactly to the size of the free cross-section of the extruder slit nozzle. In the case of a flat rectangular extruder nozzle slot channel, a truncated rotatably slidably mounted metal cylinder (2) is in each case sealingly embedded in the orifice housing (1), in the upper and lower walls of the flow-through slot defining the orifice means, at right angles to the flow direction, over the entire slot width. When the orifice is fully open, the cut surfaces of these cylinders are flush with the flow channel wall (3). The metal cylinder (2) is adjusted in a controlled or adjustable manner by hand or by means of two servomotors from the outside of the orifice housing (1) such that the orifice narrows on one side or symmetrically to the longitudinal axis of the nozzle, which corresponds to the maximum degree of closure of the slit passage cross section at a rotation angle of 90 ° (for more detailed information, see fig. 1 for a description of the drawings).

Activating the opening mechanism d) to produce a secondary mixed stream (mix open, MOP) in the extruder cooling nozzle can be done by means of the VDSA device only. In case (d), the device is integrated into the nozzle at a position between 10-95% of the nozzle length measured from the nozzle outlet end. In the case of a severely disintegrated extrudate structure, this ensures that the disintegrated extrudate structure is partially re-integrated on the remaining section of the nozzle after passing through the orifice, thereby avoiding slumping of the extrudate strands at the nozzle outlet.

In order to use the tapping mechanism (a) due to sudden residual pressure release, the VDSA device is integrated into the nozzle at a position between 0-10% of the nozzle length measured from the nozzle outlet end. This ensures that a sudden release of the static residual pressure occurs just before or directly at the nozzle outlet and thus opens towards the extrudate surface.

If the extrudate is additionally subjected to a partial vacuum suddenly for the purpose of opening a hole, the cut extrudate portion is subjected to a post-treatment in a separate, quasi-continuously operated vacuum device immediately after the nozzle outlet. This additional processing variant is preferably performed for softer extrudates, which in the case of protein-based meat-like products have a higher nozzle outlet temperature or a higher water content.

When using the open-cell variant (c) directly for multiple needle penetration (open penetration, POP) after the partially cooled product leaves the extruder cooling nozzle, in an embodiment of the preferred device according to the invention, at the extruder nozzle outlet two counter-rotating hollow needles or barbed felt needle rolls are mounted in the following manner: the needles that pierce the extrudate from both sides intermesh and the rotation of the needle rollers preferably takes place without auxiliary drive, driven only by the feed of the extrudate through the gap between the two needle rollers (see figure 5 for more details, see the description of the drawings).

When applied in the outlet area of the extruder cooling nozzle by means of a variant (c) of separating or stripping product (cut open, COP) openings, the cutter/debarking knife arrangement is arranged adjacent to the outlet front or directly at the extrudate strand outlet of the extruder nozzle. The extrudate strand feed is thus used to achieve the cutting force. Thus, the foam cells located inside are open towards the newly created product surface. This is especially true when a "skin" is formed in the nozzle flow that is depleted of foam cells.

Some advantages are

Except for the additional vacuum application to activate the opening mechanism (a) to set a rapid ambient pressure drop (flash-open, FOP), and the freeze structuring to activate the opening mechanism (e) to pierce the walls of the holes by means of ice crystals (freeze-open, FOP), all other devices have a simple structure and are arranged directly in or coupled with the extruder nozzle. This results in particular advantages of the direct couplability of these mechanisms and associated device variants. All these devices are insensitive to contamination, mechanically robust and easy to preset, so that no further operations are necessary in the preparation process.

The opening can be performed efficiently and reproducibly by means of a device configured according to the invention, wherein the quality and extent of the opening is also determined by the material behaviour of the extrudate. Such extrudates must have a substantial strength or yield point which ensures that the resulting openings are not re-closed by the merging of the matrix materials. Since the opening mechanisms (a) - (e) and the device according to the invention provided for this purpose can be simply superimposed, which is advantageous according to the invention, a sufficient opening efficiency can be ensured even for demanding soft extrudates.

Other embodiments of the invention

Other embodiments of the invention are described in claims 27 to 34.

Achievement of the object concerning the use

This object is achieved by the features of claim 35, characterized in that the resulting foamed product with a regulated cell opening is used as a structured base element of a meat-like product, wherein the protein used is of vegetable origin only, and that such a meat-like product base element is used in a menu, which brings about a gradual to complete filling of the cell opening of the structured base element by means of a complementary, fluid sauce or juice or condiment or marinade or gravy component.

Other embodiments of the invention

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

Some advantages are

The fibril structured meat-like products that can currently be prepared using High Moisture Extrusion Cooking (HMEC) technology based on vegetable proteins have a compact structure that is not sufficiently close to the consumer's combined organoleptic requirements for truly comparable texture, taste and some nutritional properties of meat to be accepted as a true substitute. The product structure with adjustable proportions of closed cells and open cells that can be achieved according to the invention is able to meet the desired properties of meat-like products, since on the one hand they can be purposefully used to provide a positive texture directly (tenderness, crispness) and a taste (juiciness) through the simple absorption capacity of the fluid system. The basic non-limiting nature of the technical package according to the invention also creates a wide field of implementation for other foamed food systems. The application to pharmaceutical and cosmetic products and to construction/construction materials is also a viable field of application.

Drawings

In the accompanying drawings, the invention is illustrated by way of example (partially schematic). In the figure:

fig. 1 shows an adjustable slit nozzle orifice (VSDA) for a flat slit nozzle in accordance with the present invention. In fig. 1, the reference numerals are as follows: 1 = orifice housing, 2 = truncated, rotatable, slidably mounted metal cylinder-2 a in 0 position with free flow cross section, 1b clockwise, 2c counter clockwise, 3 = slit nozzle wall, 4a-4c = orifice inlet flow adjusted for different rotating metal cylinders according to 2a-2c, 5a-5c = orifice outlet flow adjusted for different rotating metal cylinders according to 2a-2c, 6 = geometric illustration for positioning said metal cylinder, α = rotation angle of metal cylinder, β = angle between metal cylinder center point and said metal cylinder cutting surface edge.

The calculation basis for the height reduction defined in the extruder nozzle flat slot channel as a function of the rotation angle delta of the rotationally adjustable metal cylinder and as a function of the metal cylinder radius R1, as well as the placement of the cutting surface (angle beta) and thus the center point coordinates R1 of the metal cylinder are shown in fig. 8.

In the case of a flat rectangular extruder nozzle slot channel, a truncated rotatably slidably mounted metal cylinder (2) is in each case sealingly but rotatably embedded in the orifice housing (1), over the entire slot width, in the upper and lower walls of the flow-through slot defining the orifice means, at right angles to the flow direction. When the orifice is fully open, the cut surfaces of these cylinders are flush with the flow channel wall (3). The metal cylinder (2) is rotatably adjusted from the outside of the orifice housing (1) by hand or by means of two servomotors, so that the orifice narrows on one side or symmetrically to the longitudinal axis of the nozzle, which corresponds to the maximum degree of closure of the slit passage cross section at a rotation angle of 90 °.

In the case of annular slot nozzles for increased extrudate mass flow, the mechanism of slot gap height adjustment is achieved by a concentric conical design of the inner wall of the nozzle housing and an axially displaceable punch with a conical tip, as shown in fig. 2.

The following reference numerals are applied to fig. 2: 7 = conical nozzle housing, 8 = axial gap adjustment ram with conical tip, 9 = adjustment ram guide tube, 10 = temperature adjustment fluid inlet into adjustment ram guide tube, 11 = temperature adjustment fluid outlet from adjustment ram guide tube, 12 = temperature adjustment fluid channels in inner (12 a) and outer (12 b) nozzle housing walls and in adjustment ram (12 c), 13 = guide rail of axial adjustment ram guide tube, 14 = nozzle gap in initial position (14 a) and with narrowing gap adjustment (14 b), 15 = annular slit nozzle inner housing wall portion, 16 = flange for connecting annular nozzle part or with extruder housing

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

The reference numerals in fig. 3 are as follows: 17 =slit nozzle flow path, 21=extrudate strand, 26=partially perforated conveyor belt, 27a=upper evacuated half-shell, 27b=lower evacuated half-shell, 28a=contact pressure pneumatic device of upper evacuated half-shell, 28b=contact pressure pneumatic device of lower evacuated half-shell, 29=truncated extrudate section, 30a, b=line for suction (partial vacuum transfer), 31=partial vacuum reservoir, 32=vacuum pump, 33=strand cutting device

POT2: the device realized according to the invention for perforating (cut open, COP) by separating or peeling the product according to the mechanism (c), applying a cutter/peeler (possibly a water jet or a laser cutting device) in the outlet area of the extruder cooling nozzle-arrangement, as schematically shown in fig. 4.

The reference numerals in fig. 4 are: 17 Slit nozzle flow path, 18 = laminar slit nozzle flow, 19 = cutting means for positioning above said slit passage height H, cutting means for positioning above slit passage width W.

POT3: the device for achieving perforation according to mechanism (c) for multiple needle penetration (open penetration, POP) is arranged directly after the extruder nozzle outlet and in an embodiment of the preferred device according to the invention two counter-rotating hollow needles or barbed felt needle rolls are combined, wherein the needles penetrating the extrudate from both sides intermesh as shown in fig. 5.

Reference numerals in fig. 5 are as follows: 17 Slit nozzle flow path, 22a = upper needle roller, 22b = lower needle roller, 23 = piercing needle (hollow needle or barbed felt needle), 24 = conveyor belt separator, 25a, b = upper and lower piercing needle roller compression separator (pneumatic/hydraulic/mechanical).

POT-4: means for achieving an opening according to mechanism d) for generating a secondary mixed flow (mix open, MOP) in the extruder cooling nozzle, which in principle can be limited to an adjustable slit nozzle orifice (VSDA) means for on-line control of the intensity of the adjusted secondary mixed flow, however, a coupling with a measuring arrangement according to the invention for determining the static pressure before and after the VSDA means is shown. In fig. 6 and 7, this pressure measurement arrangement is shown in combination with the VDSA device.

Fig. 7 includes an extension of the pressure measurement arrangement from fig. 6 for the case of viscoelastic fluids such as those present in the case of protein melts used to prepare meat analog products.

Reference numerals in fig. 6 and 7 are as follows: 1 = orifice housing, 2 = truncated, rotatable, slide mounted metal cylinder-2 b rotated clockwise, 3 = slit nozzle wall, 4b = orifice inlet flow (2 b) of clockwise rotating metal cylinder, 5b = orifice outlet flow of clockwise rotating metal cylinder (2 b), 17 = slit nozzle flow channel, 35 = membrane-pressure sensor P1 for static pressure measurement; 36 Membrane-pressure sensor P2, 37 for static pressure measurement = membrane-pressure sensor P3 for static pressure measurement, 38 = membrane-pressure sensor P4 for static pressure measurement, 39 = pressure sensor membrane, 40 = connection flange, 41 = conical nozzle inlet flow geometry, 42 = membrane-pressure sensor P5 for static pressure measurement, 43 = P5-pressure measurement chamber.

For extrusion fluids of significant viscoelasticity, such as those corresponding to foaming protein melts, the VSDA described above is installed in the extruder nozzle according to the present invention at a greater distance from the nozzle outlet than the POT-1 technology. In viscoelastic product fluid systems, the above-mentioned secondary flows are decisively forced by the action of elastic turbulence (relaxation of elastic abnormal stresses and the resulting reverse deformation of the strands) as a result of the narrowing and re-widening of the adjustable channel cross-section. This effect can be triggered even if the slit nozzle cross section is slightly narrowed, and its characteristics can be specifically adjusted and used to create an open pore structure.

For this purpose, according to the invention, as shown in fig. 6, the static pressure measurement is carried out in one position in the extruder housing before the nozzle inlet cross section (P1), in the extruder slit nozzle at two longitudinal positions (P2, P3), after the nozzle inlet zone (after conical narrowing) (P4), and in the slit nozzle channel before said VSDA (P5), directly opposite to the pressure measurement position P2 (slit nozzle channel underside).

From P2 and P3, the local shear stress τ on the slit nozzle passage wall can be determined _W And the product shear viscosity η is determined knowing the product volumetric flow rate dV/dt measured at the nozzle outlet. When P1 is included, the nozzle inlet pressure loss ΔP can be determined _{An inlet} Which is the sum of (i) and (ii) below, (-)i) Viscous elongational pressure loss ΔP under the action of elongational viscosity of an extrusion fluid _{D, inlet} And (ii) an elastic pressure loss component ΔP due to elastic energy storage _{E, inlet} . By means of the additional static pressure measuring device P5, the purely elastic parameter fluid response can be determined between the measuring points from P5-P2, between P5 and P2, by the reverse deformation caused by elastic stress relaxation. P2-P5 is proportional to the so-called first normal stress difference N1, which is measured in rheological laboratory measurements using the cone-plate shear gap geometry and can be compared to the values measured on-line or from which a calibration can be derived. From P2-P5, the nozzle inlet pressure loss ΔP can be determined therefrom _{An inlet} Elasticity component DP of (2) _{E, inlet} Thereby also obtaining DeltaP _{An inlet} Is a complementary viscous extension component Δp of (a) _{D, inlet} . The arrangement according to the invention of the pressure measurement points P1 to P3 and P4 thus provides separate rheological parameters for (a) the shear viscosity, (b) the elongational viscosity and (c) the elasticity of the extruded material under the given extrusion conditions. In the case of pressure measurement P5, it should be noted in particular that this measurement is not through the membrane of the pressure sensor flush with the wall in the slit nozzle channel as in all other pressure measurements (P1-P4), but at the end of the cavity filled with extrusion fluid, which cavity has a rectangular cross section extending in the flow direction (narrow) (e.g. having a nozzle channel width of 60 mm: 10X 50 mm) for measuring the first normal stress difference from P2-P5. The pressure measurement P4 is made at one location in the slit nozzle passage immediately after the constriction (slit nozzle passage height decrease Δh) produced by means of the VSDA device. In this way, periodic static pressure fluctuations DP4 (t) are captured, which are generated in particular by the forced secondary mixed flow in the subsequent flow of the VSDA. According to the invention, these fluctuations are a measure of the mixing strength according to mechanism (d) indicated and described above and the foam cell opening efficiency associated therewith.

As surprisingly found in laboratory rheology measurements of high volume polymer fluid systems, "elastic turbulence phenomenon" (also known in the plastics industry as melt fracture) is an effective wall shear rate g at the slit nozzle channel wall _w Next, at the firstNormal stress difference and shear stress N ₁ (γ _w )/τ(γ _w ) Appears within a certain range of the ratio of (2). The range is 2-N ₁ (γ _w )/τ(γ _w )<5. The characteristic of the elastic turbulence effect utilized according to the invention is used to open foam cells by forcing a secondary mixed flow, preferably at 2.ltoreq.N, using the mechanism (d) according to the invention ₁ (γ _w )/τ(γ _w )<3.5-5. As the ratio value increases, the secondary mixed flow effect gradually increases. Depending on (i) the rheology of the extruded fluid system (here preferably a vegetable protein based melt for meat analogue preparation) and the average flow rate in the slit nozzle channel, the VSDA device is adjusted with respect to the reduction of the slit nozzle height to obtain the desired degree of secondary mixed flow with associated open cell effect. Thus, by means of a specific calibration according to the material system, quantitative criteria for adjusting the VSDA slit opening for triggering or adjusting the gradual characteristic of the forced "elastic turbulent secondary flow mixing effect" can be determined, which can make the opening of the aperture of the invention possible by means of POT-4 technology and thus the mechanism (d) triggered in an adjustable manner.

The characteristics of the viscoelastic secondary flow effect for POT-4 can result in nearly complete disintegration of the extruded strands. In plastics technology, this undesirable elastic phenomenon is also known as "melt fracture". To avoid this, the VSDA device is installed in accordance with the invention before the extruder nozzle tip>0.2L _D (L _D =nozzle length). Thus, upon completion of the partial disintegration, the extrudate strands "heal" again in the undisturbed nozzle flow after passing through the VSDA to the extent that: a dense cohesive, foamed partially open-celled product strand is produced without disrupting the open cell effect achieved by the elastic turbulent mixing by repeated flow-related "skin formation".

Exemplary configurations of vegetable protein-based meat analog products and cell opening degrees according to the present invention, as achieved using the method of the present invention with the apparatus of the present invention, are shown in fig. 8-10, and described below.

Detailed Description

The basic conditions for the examples given below are:

HMEC extruder: a co-rotating twin screw BCTL extruder from buhler AG, having a screw diameter of 42mm and an extruder length to screw diameter ratio of L/d=28.

Extruder cooling nozzle: l=1.85 m, w=60 mm, h=15 mm

Materials/base formulation: 52.5% water, 0.5% oil, 41.2% Pea Protein Isolate (PPI), pea fibre 5.8%

The method comprises the following steps: screw speed: 230rpm, mass flow rate 37.5kg/h; the nozzle inlet temperature of the melt is 150 ℃; extruder outlet pressure: 18-20 bar, nozzle cooling temperature: 60 ℃ example 1 (see fig. 9): the mechanism of opening the pores is achieved by means of (a) abrupt residual pressure relief and (d) superimposed forced secondary mixed flow.

The different opening degrees are achieved by (a) by means of superimposed opening mechanismsFast pressure drop(static residual pressure relief) and (d)Forced secondary mixed flowRegulating the forced secondary mixed flow by means of mounting onNozzle outletAn adjustable slot-nozzle orifice (VSDA) at the end with a different adjusted slot channel height reduction Δh/%:

picture a: ΔH is approximately 5%/the pore opening degree POG is approximately 3-5%

Picture B: ΔH is about 10%/the pore opening degree POG is about 10-12%

Picture C: ΔH approximately 50%/pore opening degree POG approximately 25-30%

The cell opening degree (POG) was determined according to the following:

POG = VOP open pore volume/VGP total pore volume. VOP was determined as follows: the extruded sample was left in water at room temperature (25 ℃) for 5 seconds and surface dried after removal of free water adhering to the surface of the strand using toilet paper in a defined quick treatment procedure (1 second on each side of the paper layer). This differential weighing before and after treatment yields the mass of water drawn into the product pores open to the product surface by capillary forces. VGP is determined by measuring the volume and mass of the extruded product from which the gas volume fraction or overrun (=relative volume increase due to foaming) relative to the product without foaming is determined.

As can be seen from fig. 9, as the VSDA slit nozzle passageway height decreases by an increasing amount, the extrudate surface shows increased "chipping" as a result of the forced secondary mixing flow being applied while releasing the residual pressure. This is a typical image of the product obtained when the VSDA is installed at the end of the nozzle.

The samples considered in this example, which were untreated with respect to open cell, had a post-foaming gas volume fraction of about 25-35% in an internal foam cell that was ≡ about 98% closed. Example 2 (see fig. 10): the opening mechanism is realized by (d)Forced secondary mixed flowBy means of mountingAt a nozzle length of 0.75m from the nozzle outletIs produced when the slit channel height is adjusted to reduce DH/% ≡15%.

Fig. 10 shows a predominantly smooth extrudate surface with clearly visible flow patterns derived from forced secondary mixing streams. These patterns "heal" due to subsequent nozzle flow (here another 0.75m. over the nozzle length, which reduces to a small extent the degree of opening achieved by the final product, but allows to produce a quality-related structural pattern according to the invention to a large extent from the consumer's point of view, reflecting the natural distribution of structural non-uniformities, as is evident in meat products (in the example shown: salmon/fish or marble-like magical beef structure).

The sample considered in this example, which was untreated with respect to open cells, had a gas volume fraction after foaming of about 15% in an internal foam cell that was ≡about 98% closed.

Example 3 (see fig. 11): the opening mechanism is realized by (d)Forced secondary mixed flowBy means of mountingAt a distance from Nozzle outlet at nozzle length of 0.3mIs adjustable-slit nozzle orifice (VSDA)When the slit channel height is adjusted to decrease DH/% -15%.

Fig. 11 shows an enlarged image of the surface of the product. The wavy stripe pattern structure is clearly visible. (H) The brighter (foam-enhanced) and (D) darker (foam-reduced) areas in a stripe arrangement alternate. Zone H originates from an internal strand foam structure that is delivered to the product surface by forced secondary mixed flow. Zone D originates from the original "surface cortex" of foam cells depletion.

The sample considered in this example, which was untreated with respect to open cells, had a gas volume fraction after foaming of about 30% in an internal foam cell that was ≡about 98% closed. The degree of opening (POG) achieved is about 18-20%.

Example 4 (see fig. 12): opening holes by means of (b) a cutting/stripping mechanism, which is created by means of an adjustable cutting device mounted at the outlet end of the nozzle.

Figure 12 shows a foamed, continuously cut extrudate strand. The open cell structure being cut out can be detected on the cut surface. An open cell of about 10-15% is achieved in the illustrated embodiment. The present examples are based on extrudates having a gas volume fraction of about 15-20%.

2-5% of the total volume of the openings is believed to be sufficient to enrich the sensory (aroma, taste) and nutritional (B vitamins, minerals (Fe, zn)) of the vegetable protein-based meat analog product described in the examples. To increase the juiciness of the product, 10% or more is relevant, depending on the water content of the product matrix.

The features described in the claims and in the description and apparent from the drawing may be essential for the implementation of the invention, both alone and in any combination.

List of reference numerals

1. Orifice shell

2. Metal cylinder

3. Slit nozzle wall

4a orifice inlet flow

4b orifice inlet flow

4c orifice inlet flow

5a orifice outlet stream

5c orifice outlet stream

6. Geometric representation for positioning the metal cylinder

7. Nozzle housing, cone shape

8. Gap adjusting punch head, axial direction

9. Guide tube for adjusting punch

10. Temperature regulating fluid inlet

11. Temperature regulating fluid outlet

12. Temperature-regulating fluid channel

12a temperature-regulating fluid passage, inside

12b temperature-regulating fluid passage, outside

12c temperature-regulating fluid passage in a regulating punch

13. Guide rail

14. Nozzle gap

14a nozzle gap in the starting position

14b through narrowing of the nozzle gap

15. Annular slit nozzle

16. Flange

17. Slotted nozzle flow channel

18. Laminar flow slit nozzle flow

19. Cutting device

20 -

21. Extrudate strands

22a needle roller, upper

22b needle roller, lower

23. Puncture needle

24. Conveyor belt separating device

25a puncture needle roller contact pressure separating device, upper part

25b puncture needle roller contact pressure separating device, lower

26. Conveyor belt, partly perforated

27a vacuumizing half shell, upper part

27b vacuum half shell, lower

28a contact pressure pneumatic device, upper

28b contact pressure pneumatic means, lower

29. Extrudate section, cut off

30a line for aspiration

30b tubing for aspiration

31. Partial vacuum storage vessel

32. Vacuum pump

33. Wire cutting device

34 -

35. Membrane-pressure sensor

36. Membrane-pressure sensor

37. Membrane-pressure sensor

38. Membrane-pressure sensor

39. Pressure sensor membrane

40. Connecting flange

41. Nozzle inlet flow geometry, taper

42. Membrane-pressure sensor

Angle of rotation of alpha metal cylinder 2

Beta is the angle between the metal cylinder centre point and the edge of the cutting surface of the metal cylinder 2

Rotation angle of delta metal cylinder 2

R ₁ Radius of metal cylinder

L _D Nozzle length

Reference to the literature

/1/V.Lammers1,A.Morant,J.Wemmer,E.Windhab(2017)；High-pressure foaming properties of carbon dioxide-saturated emulsions；Rheol Acta(2017)56:841-850

2/E.Windhab, V.Lammers (2017); patent: teigbasiertes Lebensmittelprodukt sowie Vorrichtung und Verfahren zur Herstellung des teigbasierten Lebensmittelprodukts; patent application number DE 10 2016 111 518 A1

/3/L.Zeng,F.Najjar,S.Balachandar,P.Fischer(2009)；Forces on a finite-sized particle located close to a wall in a linear shear flow；Physics of Fluids 21,033302,2009

4/D.Legendre, J.Magnaudet (1998); the lift force on a spherical bubble in a viscous linear shear flow; j Fluid Mech (1998), volume 368, pages 81.+ -. 126. #1998Cambridge University Press)

/5/P.J.Fellows(2016)；Food Processing Technology:Principles and Practice；Woodhead Publishing Series in Food Science,Technology&Nutrition；Woodhead Publishing,2016；ISBN 0081005237,9780081005231

/6/P.J.Hailing&P.Walstra(1981)Protein-stabilized foams and emulsions,C R C Critical Reviews in Food Sci.&Nutrition,15:2,155203,DOI:10.1080 / 1040839810952 7315

7/Ashley J. Wilson (1989) Foams: physics, chemistry and Structure; springer-Verlag London, ISBN 978-1-4471-3809-9.

8/N.Mills (2007); polymer Foams Handbook; finely packed ISBN 9780750680 691; version description: butterworth-Heinemann).

/9/US6,635,301 B1

/10/WO2016/150834 A1

/11/EP1182937 A4

/12/WO2009075135

/13/US20050003071 A1

/14/WO2016150834 A1

/15/US10,716,319 B2

/16/WO 2017/081271 A1

/17/KR 1020200140499 A

/18/US2020/0060310 A1

Claim (modification according to treaty 19)

1. A foamed, resilient protein-based product having a dry matter fraction of 20-60 wt%, a bound water fraction of ≡40 wt% and an air cell structure, wherein the following parameters are adjusted:

(i) The ratio of open gas-filled pores (OP) towards the product surface to closed gas-filled pores (GP) in the product volume is adjusted in the range of 0.05-0.95 with a precision of +/-0.05 for values of >0.1 for this ratio; and

(ii) The gas volume fraction was adjusted between 0.1 and 0.8 with a precision of +/-0.05.

2. The product according to claim 1, characterized in that it has a protein fraction of 10-95% by weight in its dry matter.

3. The product according to claim 1 or 2, characterized in that the protein fraction comprises 0-100 wt.% of vegetable proteins.

4. The product according to claim 1 or any one of the following claims, wherein the protein in the product is present in a partially to fully denatured form and has a fibrillar structure.

5. The product of claim 4, wherein the denatured form has an oriented fibrillar structure.

6. The product according to claim 1 or any one of the following claims, characterized in that it comprises a plant fiber fraction of 0.5-20% by weight on a dry matter basis.

7. The product according to claim 1 or any one of the following claims, characterized in that it comprises a fat or oil number of 0.1-15% by weight on a dry matter basis.

8. A product according to claim 1 or any one of the following claims, characterized in that the product comprises flavouring and/or colouring components and/or components that increase the nutritional value in addition to the vegetable fibre fraction in a proportion of 0.1-5% by weight on a dry matter basis.

9. The product according to claim 1 or any one of the following claims, wherein after drying to a residual water content of 5% by weight or less and storage under humidity control conditions for several months without spoilage at room temperature, the product is reconstituted to regain its original volume and its texture upon contact with water or an aqueous fluid system without loss of dry matter.

10. The product according to claim 1 or any one of the following claims, wherein after drying to a residual water content of 5% by weight or less and storage under humidity-controlled conditions without spoilage for several months at room temperature conditions, the product is reconstituted to regain its original volume and its texture upon contact with water or an aqueous fluid system.

11. A method of preparing a product according to claim 1 or any one of the following claims, characterized in that the method achieves opening of cells or bubbles enclosed in the foamed product towards the surface of the product in such a way that: the gas volume fraction is between 0.1 and 0.8, preferably 0.1-0.5, the accuracy of the adjustment in terms of the volume ratio of open pores to closed pores towards the surface of the product is +/-0.05, the ratio ranging from 0.1-0.9, wherein the extrusion process is based on the "high moisture extrusion cooking" (High Moisture Extrusion Cooking, HMEC) type, with gas entry, temporary gas dissolution and controlled bubble nucleation and foam formation, and the following five process variants are employed individually or jointly for opening pores: (a) opening by rapid drop of ambient pressure (rapid opening, FOP), (b) opening by separation or peeling of product (cut opening, COP), (c) opening by multiple needle puncture (puncture opening, POP), (d) opening by forced secondary mixed flow (mixed opening, MOP) and (e) opening by freeze structuring (freeze opening, FOP).

12. The method according to claim 11, characterized in that the closed pores are opened towards the product surface by means of an opening mechanism (a) by a rapid drop in ambient pressure (flash-open, FOP) and (b) by separating or stripping the product in the outlet area of the extruder cooling nozzle (cut open, COP) and an opening mechanism (d) by a forced secondary mixed flow in the extruder cooling nozzle (mix open, MOP) by means of an opening mechanism (c) by freeze structuring after the partially cooled product leaves from the extruder cooling nozzle.

13. The method according to claim 11 or 12, characterized in that opening the closed pores towards the product surface by means of (a) a rapid drop in ambient pressure (quick-open, FOP) is achieved by maintaining the static pressure by means of an adjustable slit-nozzle orifice (VSDA) until the pressure level in front of the adjacent nozzle outlet is ≡2 bar, said slit-nozzle orifice being mounted at or in front of (+.10 cm) the extruder nozzle outlet depending on the viscosity of the exiting fluid material is adjusted to the static pressure prevailing before said VSDA in such a way that the opening of the inner pores towards the product surface gives the number fraction of pores open towards the product surface also for product specific adjustment, based on the total number of closed pores and open pores.

14. A method according to claim 11 or any one of the following claims, characterized in that opening the closed holes towards the product surface is achieved by (a) opening the holes by a rapid drop in ambient pressure (snap-open, FOP) by suddenly applying a partial vacuum of 100 mbar or less to the extrudate strand portion in a quasi-continuously operated vacuum chamber device after it has been cut.

15. A method according to claim 11 or any one of the following claims, characterized in that opening the closed holes towards the product surface is achieved by means of (b) separation or peeling of the product (cut open, COP) by continuously cutting the extrudate strands or peeling off the surface layers thereof using a cutting device mounted at the end of the extruder slit nozzle.

16. A method according to claim 11 or any one of the following claims, wherein the opening of the closed pores towards the product surface is performed by means of (c) multiple needle punctures (puncture opening, POP), thereby creating a connecting channel between the inner closed pores or bubbles and the product surface of 0.1-2mm diameter.

17. A method according to claim 11 or any one of the following claims, wherein the opening of the closed pores towards the product surface is performed by means of a mechanism (d) according to the invention: (d) Forced secondary mixed flow (mix open, MOP), wherein by local cross-section narrowing of the extruder slit nozzle by means of an adjustable slit-nozzle orifice (VSDA) mounted inside the extruder cooling nozzle, a roll-shaped secondary flow is produced which is also adjustable in terms of its strength and accompanying mixing efficiency in the direction of the slit height extension of said nozzle gap, via an adjustable slit gap height reduction with the slit-nozzle orifice after the resulting narrowing, wherein the roll flow rotation axis is oriented transversely to the main flow direction over the nozzle slit width.

18. A method according to claim 11 or any one of the following claims, wherein the opening of the closed pores towards the product surface is performed by means of a mechanism (d) according to the invention: (d) Forced secondary mixed flow (mix open, MOP), wherein for viscoelastic aqueous protein melt and other viscoelastic fluid systems, by achieving local cross-section narrowing of the extruder slit nozzle by means of an adjustable slit-nozzle orifice (VSDA) installed therein, by means of a slit nozzle height reduction after narrowing by means of an adjustable thereof, a secondary flow is produced which is also an adjustable roll-shaped periodic fluctuation in terms of its intensity and accompanying mixing efficiency in the slit height extension direction of the nozzle gap, wherein the roll flow rotation axis is oriented transversely to the main flow direction over the nozzle slit width, and wherein the intensity of the secondary flow mixing effect is quantitatively described by means of an online measurement of the amplitude of the variation curve of the static pressure of sinusoidal oscillations before or after the VSDA over time according to the invention, and is stepwise adjusted by adjusting the nozzle slit gap width within the VSDA device.

19. The method according to claim 11 or any one of the following claims, characterized in that the gap narrowing is achieved by adjusting the slit height by means of an adjustable slit-nozzle orifice (VSDA) according to material parameters of viscosity and elasticity of an extruded fluid material under extrusion conditions measured rheologically in a cone-plate-shear gap, either on-line or off-line, according to the invention, wherein the viscosity properties are described by shear stress τ as a function of shear rate γ, and the elasticity properties are described by a first normal stress difference N as a function of shear rate γ ₁ Described, and the gap of the slit nozzle is narrowed byImplemented in such a way as to satisfy the apparent wall shear rate gamma for dominance in the narrowed slit nozzle gap _sw The ratio N of ₁ In terms of/τ, the relation 2.ltoreq.N is maintained ₁ /τ)<5。

20. The method according to claim 11 or any one of the following claims, characterized in that the online measurement of the static pressure profile before or after the VSDA in a simplified manner only considers the magnitude of the static pressure oscillation fluctuations as a precondition for adjusting the slot gap narrowing, the secondary flow mixing effect thereby occurring in the subsequent flow of the orifice and the opening of the associated internal closed foam cells towards the slot nozzle wall and thus towards the extrudate surface and creating new cell channels or gaps that are open towards the product surface.

21. A method according to claim 11 or any of the following claims, characterized in that the opening of closed cells towards the surface of the product is performed by means of (e) freeze structuring, wherein the rapid cooling of the product is performed after the extrusion nozzle outlet, and the cooling post-treatment is performed within the temperature range between-1 and-20 ℃, preferably under periodic temperature control, within these limits.

22. A method according to claim 11 or any one of the following claims, wherein the product is gently dried after partial aperturing to a residual water content that allows humidity controlled product storage at room temperature for months without microbial or enzymatic spoilage.

23. A method according to claim 11 or any one of the following claims, wherein the product is reconstituted by absorption of water or fluid after partial aperturing and gentle drying to a residual water content that allows humidity controlled storage of the product for months at room temperature.

24. Device for carrying out the method according to claim 11 or any one of the following claims, characterized in that (i) a cutting device and/or (ii) an adjustable slit nozzle orifice (VSDA) are integrated in the temperature-regulated extruder nozzle channel and/or (iii) a rapid vacuum device and/or (iv) a fluid infusion device and/or (v) a cooling/freezing device are arranged downstream of the extruder nozzle and these devices are coupled with an adapted measuring sensor/measuring technique which measures the extent of the effect of the regulated opening of the foam cells of a specific proportion by means of the devices (i) - (v).

25. The device according to claim 24, characterized in that the extrusion nozzle has a downstream cutting device (33) and a downstream conveyor belt (26), which is partly perforated in the middle of the cross section of the cooling nozzle of the HMEC foaming extruder, and that the conveyor belt (26) together with the cut-out portion of the product placed above is guided between two evacuating half-shells (27 a,27 b), which close the conveyor belt (26) and the product in a closed manner pressed against each other from above and below, and in that these evacuating half-shells are connected to a vacuum reservoir (31) via a vacuum line provided with a quick-opening valve and the vacuum reservoir is connected to a vacuum pump in order to suddenly apply a partial vacuum to the foamed extruded product.

26. The apparatus according to claim 25, characterized in that in the extruder nozzle outlet, a cutter or a fine cutting line or a water jet or a laser cutting device, which is embedded in a slit nozzle channel to ensure guiding of the product strand, is arranged with a small blade width of 2mm or less, so that (i) the surface layer with a layer thickness of 1mm or less is cut or peeled off, or (ii) the product strand is divided in the middle in the slit height direction.

27. Device according to claim 25 or 26, characterized in that at the nozzle outlet two rotatable suspended needle rollers (22 a,22 b) are arranged, equipped with barbed solid needles-felt needles-or hollow needles with a needle diameter of between 0.3-5mm, between which extruded product formed in a band as extrudate strand (21) is guided, and the needle penetration depth is adjusted between 1-20mm, depending on the shape of the product, and the penetration number density is adjusted between 1-49/cm ² Between them.

28. The apparatus according to claim 25 or any one of the following claims, characterized in that one slit-nozzle orifice (VSDA) is arranged adjustable in gap width between 10-100% of the slit channel height of the extrusion nozzle, between 10-50% of the nozzle length in case of pure viscous flow properties of the unhardened or partially hardened fluid system of case (a), between 5-95% of the nozzle length in case of viscoelastic flow properties of the unhardened or partially hardened fluid system of case (B), before the nozzle end of the cooled extruder slit nozzle, or directly at the nozzle end.

29. The device according to claim 25 or any one of the following claims, characterized in that the slit-nozzle orifice (VSDA) adjustable in the gap width between 10-100% of the slit channel height of the extrusion nozzle corresponds exactly to the dimension of the free extruder slit nozzle cross section in its 100% open state, and in the case of existing flat rectangular extruder nozzle slit channels, truncated rotatably slidably mounted metal cylinders are sealingly embedded in the upper and lower walls of the flow-through slit defining the orifice device in each case at right angles to the flow direction, wherein the cutting surfaces of these cylinders are flush with the flow channel wall when the orifice is fully opened, and that an adjustable narrowing of the orifice on one side or symmetrically to the longitudinal axis of the nozzle is achieved, which corresponds to the maximum degree of closure of the slit channel at a rotation angle of 90 ° when the rotation of the cylinder from the outside is effected by hand or by means of a servomotor.

30. The apparatus according to claim 25 or any one of the following claims, characterized in that the inserted slit-nozzle orifice (VSDA) adjustable in gap width between 10-100% of the extrusion nozzle slit channel height corresponds exactly to the size of the free extruder-slit nozzle cross-section in its 100% open state, and in the case of extruder nozzles for higher throughput efficiency with annular gap, a piston-like ram with a conical attachment is arranged to narrow the annular slit gap, which preferably determines a defined narrowing of the annular slit gap by means of defined axial insertion into the extruder outlet nozzle accomplished by means of a servo motor, which outlet nozzle is conically designed to accommodate the extruder annular slit nozzle.

31. The device according to claim 25 or any of the following claims, characterized in that according to the invention the extruder cooling nozzle and the extruder nozzle inlet are equipped with 4-5 sensors (P1-P4, P5) for static pressure measurement, wherein preferably one of the sensors (P1) is arranged flush with the wall before the extruder nozzle inlet and three of the sensors (P2-P4) are arranged in the extruder slit nozzle, wherein two (P2, P3) are flush with the wall before the slit channel constriction regulated by means of the VSAD, and one (P4) is also arranged flush with the wall, directly in the outlet flow of the slit channel constriction, and in case of viscoelastic fluid properties an additional fifth sensor (P5) for static pressure measurement is placed directly on the opposite side of the slit channel with respect to sensor P2, but not flush with the wall, but in a cavity (43) inserted in the bottom of the slit nozzle, and wherein the rectangular cavity has a cross-sectional dimension of the range of preferably 1 x-6 cm-4 cm (1 x-3 cm).

32. The device according to claim 25 or any one of the following claims, characterized in that the sensors P1 to P3 for static pressure measurement are integrated flush with the wall into a flat slit flow channel for online detection of apparent rotational viscosity and shear viscosity in the nozzle inlet flow, and that the sensors P2 and P5 for static pressure measurement are mounted in the flow channel height direction orthogonal to the flow direction and directly opposite each other, P2 being mounted flush with the wall in the flow channel, P5 not being mounted flush with the wall but on the cavity bottom with rectangular cross section for determining the pressure difference proportional to the elastic normal stress difference, and that the sensor P4 is integrated in the flow channel flush with the wall and after the adjustable slit-nozzle orifice (VSDA) in the flow direction for measuring the oscillating pressure fluctuations caused by the secondary flow.

33. The apparatus according to claim 25 or any one of the following claims, characterized in that the extruder nozzle outlet is connected to a cooling impregnation bath for cooling the extrudate strands below-20 ℃, preferably below-50 ℃, and in accordance with the invention two freezing chambers are connected downstream for periodic (1-2 hours duration) product rearrangement, wherein these freezing chambers are adjusted to be constant-1 ℃ and-20 ℃.

34. Use of a product according to claim 25 or any of the following claims, characterized in that the resulting foamed product with an adjusted (i) cell size of between 0.1-0.9 and (ii) gas volume fraction of between 0.1 and 0.8, each with an adjustment accuracy of +/-0.05, is used as a structured base element of a meat analogue product, wherein the protein used is of vegetable origin only, and such meat analogue product base element is used in a menu, bringing about a gradual to complete filling of the cells of the structured base element by means of a complementary, fluid sauce or juice or dressing or marinade or gravy component.

35. Use according to claim 34, characterized in that the product is used as a component in cheese, candy, baked goods, wafer and chocolate candy.

Claims

1. A foamed, resilient protein-based product having a dry matter fraction of 20-60 wt%, a bound water fraction of ≡40 wt% and an air cell structure, wherein the ratio of open gas filled cells (OP) towards the surface of the product to closed gas filled cells (GP) in the volume of the product is adjusted in the range of 0.05-0.95.

11. A method for the preparation of a product according to claim 1 or any of the following claims, characterized in that the method achieves in an adjustable manner the opening of cells or bubbles enclosed in a foamed product towards the surface of the product, wherein the extrusion method is based on the "high moisture extrusion cooking" (High Moisture Extrusion Cooking, HMEC) type, with gas entry, temporary gas dissolution and controlled bubble nucleation and foam formation, and the following five method variants are employed for opening the pores, alone or in combination: opening (rapid opening, FOP) by rapid drop of ambient pressure, (b) opening (cut opening, COP) by separation or peeling of the product, (c) opening by multiple needle puncture (puncture opening, POP), (d) opening by forced secondary mixed flow (mixed opening, MOP) and (e) opening by freeze structuring (freeze opening, FOP), whereby opening of cells or bubbles enclosed in the foamed product towards the product surface is achieved in an adjustable manner.

13. The method according to claim 11 or 12, characterized in that opening the closed pores towards the product surface by means of (a) a rapid drop in ambient pressure (quick-open, FOP) is achieved by maintaining the static pressure by means of an adjustable slit-nozzle orifice (VSDA) installed at or adjacent (10 cm) to the extruder nozzle outlet, depending on the viscosity of the exiting fluid material, until the pressure level in front of the nozzle outlet is ≡2 bar, in such a way that the opening of the inner pores towards the product surface gives a fraction of the number of pores open towards the product surface, based on the total number of closed pores and open pores, which are also adjusted specifically for the product.

19. The method according to claim 11 or any one of the following claims, characterized in that the gap narrowing is achieved by adjusting the slit height by means of an adjustable slit-nozzle orifice (VSDA) according to material parameters of viscosity and elasticity of an extruded fluid material under extrusion conditions measured rheologically in a cone-plate-shear gap, either on-line or off-line, according to the invention, wherein the viscosity properties are described by shear stress τ as a function of shear rate γ, and the elasticity properties are described by a first normal stress difference N as a function of shear rate γ ₁ The gap narrowing with the slit nozzle is described as being implemented in such a way that the apparent wall shear prevailing in the narrowed slit nozzle gap is satisfiedCut rate gamma _sw The ratio N of ₁ In terms of/τ, the relation 2.ltoreq.N is maintained ₁ /τ)<5。

23. A method according to claim 11 or any one of the following claims, wherein the product is reconstituted by absorption of water or fluid after partial aperturing and gentle drying to a residual water content that allows humidity controlled product storage for months at room temperature conditions.

24. The method according to claim 1 or any one of the following claims, wherein the value of the cell opening is adjusted to be ≡0.1 with a precision of +/0.05.

25. The method according to claim 1 or any one of the following claims, characterized in that the gas volume fraction (=porosity) is also adjusted between 0.1 and 0.8 with a precision of +/-0.05.

26. Device for carrying out the method according to claim 11 or any one of the following claims, characterized in that the extrusion nozzle has a downstream cutting device (33) and a downstream conveyor belt (26), which is partly perforated in the middle of the cross section of the cooling nozzle of the HMEC foaming extruder, and that the conveyor belt (26) together with the cut-out portion of the product placed above is led between two evacuating half-shells (27 a,27 b), which close the conveyor belt (26) and the product in a tight manner pressed against each other from above and below, and in that these evacuating half-shells are connected to a vacuum reservoir (31) and the vacuum reservoir is connected to a vacuum pump via a vacuum line equipped with a quick-opening valve in order to suddenly apply a partial vacuum to the foamed extruded product.

27. The apparatus according to claim 26, characterized in that in the extruder nozzle outlet, a cutter or a fine cutting line or a water jet or a laser cutting device of a small blade width of 2mm or less is arranged to be embedded in a slit nozzle channel to ensure guiding of the product strand so that (i) the surface layer with a layer thickness of 1mm or less is cut or peeled off, or (ii) the product strand is divided in the middle in the slit height direction.

28. Device according to claim 26 or 27, characterized in that at the nozzle outlet two rotatable suspended needle rollers (22 a,22 b) are arranged, equipped with barbed solid needles-felt needles-or hollow needles with a needle diameter of between 0.3 and 5mm, between which extruded product formed in the form of an extrudate strand (21) in the shape of a strip is guided, and the needle penetration depth is adjusted between 1 and 20mm,depending on the shape of the product, and the puncture density is adjusted to 1-49/cm ² Between them.

29. The apparatus according to claim 26 or any one of the following claims, characterized in that one slit-nozzle orifice (VSDA) is arranged adjustable in gap width between 10-100% of the slit channel height of the extrusion nozzle, between 10-50% of the nozzle length in case of pure viscous flow properties of the unhardened or partially hardened fluid system of case (a), between 5-95% of the nozzle length in case of viscoelastic flow properties of the unhardened or partially hardened fluid system of case (B), before the nozzle end of the cooled extruder slit nozzle, or directly at the nozzle end.

30. The device according to claim 26 or any one of the following claims, characterized in that the slit-nozzle orifice (VSDA) adjustable in the gap width between 10-100% of the slit channel height of the extrusion nozzle corresponds exactly to the dimension of the free extruder slit nozzle cross section in its 100% open state, and in the case of existing flat rectangular extruder nozzle slit channels, truncated rotatably slidably mounted metal cylinders are sealingly embedded in the upper and lower walls of the flow-through slit defining the orifice device in each case at right angles to the flow direction, wherein the cutting surfaces of these cylinders are flush with the flow channel wall when the orifice is fully opened, and that an adjustable narrowing of the orifice on one side or symmetrically to the longitudinal axis of the nozzle is achieved, which corresponds to the maximum degree of closure of the slit channel at a rotation angle of 90 ° when the rotation of the cylinder from the outside is effected by hand or by means of a servomotor.

31. The apparatus according to claim 26 or any one of the following claims, characterized in that the inserted slit-nozzle orifice (VSDA) adjustable in gap width between 10-100% of the extrusion nozzle slit channel height corresponds exactly to the size of the free extruder-slit nozzle cross-section in its 100% open state, and in the case of extruder nozzles for higher throughput efficiency with annular gap, a piston-like ram with a conical attachment is arranged to narrow the annular slit gap, which preferably determines a defined narrowing of the annular slit gap by means of defined axial insertion into the extruder outlet nozzle accomplished by means of a servo motor, which outlet nozzle is conically designed to accommodate the extruder annular slit nozzle.

32. The device according to claim 26 or any of the following claims, characterized in that according to the invention the extruder cooling nozzle and the extruder nozzle inlet are equipped with 4-5 sensors (P1-P4, P5) for static pressure measurement, wherein preferably one of the sensors (P1) is arranged flush with the wall before the extruder nozzle inlet and three of the sensors (P2-P4) are arranged in the extruder slit nozzle, wherein two (P2, P3) are flush with the wall before the slit channel constriction regulated by means of the VSAD, and one (P4) is also arranged flush with the wall, directly in the outlet flow of the slit channel constriction, and in case of viscoelastic fluid properties an additional fifth sensor (P5) for static pressure measurement is placed directly on the opposite side of the slit channel with respect to sensor P2, but not flush with the wall, but in a cavity (43) inserted in the bottom of the slit nozzle, and wherein the rectangular cavity has a cross-sectional dimension of the range of preferably 1 x 6 cm-4 cm (1 x-3 cm).

33. The device according to claim 26 or any one of the following claims, characterized in that sensors P1 to P3 for static pressure measurement are integrated flush with the wall in a flat slit flow channel for online detection of apparent rotational viscosity and shear viscosity in the nozzle inlet flow, and that sensors P2 and P5 for static pressure measurement are mounted in the flow channel height direction orthogonal to the flow direction and directly opposite each other, P2 being mounted flush with the wall in the flow channel, P5 not being mounted flush with the wall but on the bottom of a cavity having a rectangular cross section for determining the differential pressure proportional to the elastic normal stress difference, and that sensor P4 is integrated in the flow channel flush with the wall and after an adjustable slit-nozzle orifice (VSDA) in the flow direction for measuring the oscillating pressure fluctuations caused by the secondary flow.

34. The apparatus according to claim 26 or any one of the following claims, characterized in that the extruder nozzle outlet is connected to a cooling impregnation bath for cooling the extrudate strands below-20 ℃, preferably below-50 ℃, and in accordance with the invention two freezing chambers are connected downstream for periodic (1-2 hours duration) product rearrangement, wherein these freezing chambers are adjusted to be constant-1 ℃ and-20 ℃.

35. Use of a product according to claim 26 or any of the following claims, characterized in that the resulting foamed product with adjusted cell size is used as a structured base element of a meat-like product, wherein the protein used is of vegetable origin only, and that such meat-like product base element is used in a menu, which brings about a gradual to complete filling of the cells of the structured base element by means of a complementary, fluid sauce or juice or a seasoning or marinade or gravy component.

36. Use according to claim 35, characterized in that the product is used as a component in cheese, candy, baked goods, wafer and chocolate candy.