EP2051597A1

EP2051597A1 - Process for manufacturing, by cold extrusion, puffed intermediate food products which are stable to heat treatment, from hydrated animal proteins

Info

Publication number: EP2051597A1
Application number: EP06794167A
Authority: EP
Inventors: Nicolas Denis; Olivier Mercier Du Paty De Clam
Original assignee: Ayam SARL
Current assignee: Ayam SARL
Priority date: 2006-07-07
Filing date: 2006-07-07
Publication date: 2009-04-29
Also published as: US20100021593A1; JP2009542244A; CN101505616A; WO2008003837A1

Abstract

Manufacture of intermediate food products and/or of textured finished products that have been puffed to a greater or lesser extent from hydrated animal proteins without the addition of additives or emulsifiers and/or texturizing agents, which are stable to heat treatment, involving the following succession of steps: (1) a raw initial pulp (A4) is prepared from fish fillets; (2) a series of operations is performed to lead to the production of stabilized pulp (B9) which may or may not be kept in the frozen state; (3) this stabilized pulp is introduced into an evacuated stuffer (110) to be fed into a cold-regulated twin-screw extruder (111) with contra-rotating screws, in which a succession of steps of filling (111A) which may or may not be accompanied by the incorporation of mixing additives (112A/B), of mixing (111B) with a view to homogenizing the ingredients, of shearing (111C) so as to increase the number of potential protein re-attachment sites, of puffing (111 E2) with incorporation of air or gas, then of conveying (111F) are carried out in such a way as to obtain a textured food product which has been puffed to a greater or lesser extent and may or may not include inclusions (C11) which is stable to heat treatment and the organoleptic and structural properties of which can be adapted and can differ from those of the raw material used.

Description

Process for the cold extrusion of thermally stable intermediate food products from hydrated animal proteins

DESCRIPTION

HISTORY OF THE INVENTION ⁹

The invention is in the field of the food industry and more particularly in that of the production of textured finished products or foams more or less abundant.

The present invention relates to an innovative process for the transformation and recovery of raw materials of halieutic origin, and, more specifically, a technology for producing novel food products having varied textural and organoleptic qualities, stable to thermal treatments, developed from various marine resources, such as fish, molluscs or crustaceans, by texturing these products in a co-rotating twin-screw extruder thermoregulated cold.

Fish, shellfish or crustaceans have always been widely consumed throughout the world in various forms, and are recognized as having significant nutritional qualities. However, in recent years, lifestyles and consumption have become Westernized and evolved, inducing a certain disaffection for this type of food when presented to consumers in their natural form. For example, the peculiar smell of fish, crustaceans and molluscs, the presence of bones and the inconvenience this may cause are perceived as unfavorable to the consumption of seafood products, especially among younger generations.

Despite this fact, seafood products are recognized as being low-calorie and high-protein foods, which has led to stability and even growth in consumption.

Nevertheless, if these products could be presented in a form more easily consumable, it would be possible to make them more attractive to the majority of consumers.

In order to counter this trend of rejection of fish and to encourage more people to consume seafood, many attempts have been made to develop these products in a more attractive and easily consumable form.

For example, techniques have been developed to produce foods with a fish-shell-like fiber-like texture by gentle cryopreservation of fish or shellfish pulp, or processes that permit the production of shellfish analogues. crab by modeling and heating of surimi paste in molds or by extrusion in a clumping solution to modify the chemical characteristics thereof.

The surimi mentioned above is a term used in Japan for disinherited fish flesh having undergone mechanical treatment, then having been washed with water and added cryoprotectants so as to preserve its shelf life in the frozen state.

From this hydrated concentrate of myofibrillar proteins, a wide variety of food products have been developed which make possible a pleasant consumption of fish flesh proteins with different taste, flavor and organoleptic aspect.

Nevertheless, when the surimi is used as raw material, a water-soluble protein can not be used during the treatment, and therefore its subsequent texturing possibilities are limited.

In addition, the production of such food products requires the implementation of operation of separation, washing and refined refining having the effect of a significant loss of yields often debatable their economic profitability of production.

Various studies have been carried out to develop a process for the production of new food products, in which the raw material, such as fish, shellfish or crustaceans, are relatively easily processed by a mechanism, or by a process. , providing intermediate food products with different intrinsic organoleptic qualities, retaining the water-soluble proteins, which can be subsequently textured and can be pleasantly consumed.

We have now succeeded in obtaining satisfactory results, when the raw materials of halieutic origin, such as mechanically desaturated fish flesh, hereinafter called stabilized pulp, are treated by a thermoregulated co-rotating twin-screw extrusion process. Cold. These products can then be easily textured in an industrial manner so as to give a finished product having a texture and an organoleptic appearance in accordance with the expectations of consumers. SUMMARY OF THE INVENTION

The present invention provides a method for processing, processing and upgrading a raw material of halieutic origin presented in the form of stabilized pulp, consisting of the use of a cold extrusion process with the aid of a twin-screw co-rotating thermoregulated extruder. Said stabilized pulp comprising one or more raw materials of halieutic origin selected from the group of fish, molluscs or crustaceans, or a mixture of the abovementioned raw materials and a mixture of additives.

The process implemented, whose purpose is the production of textured products or foams, more or less abundant, from hydrated animal proteins, without the addition of additives or emulsification and / or texturing ingredients, stable to heat treatments (pasteurization, sterilization), associates one or more vacuum pushers feeding a co-rotating twin-screw extruder on which is adapted one or more controlled air incorporation systems.

BACKGROUND AND PRINCIPLE

In the prior art, traditional foams or structured food products made from fish products are generally manufactured in two successive stages:

- hot pre-melt with incorporation of ingredients or additives allowing a pre-emulsion

and then a second step of cold incorporation of the proteins so as to avoid denaturation by heat of the latter.

These methods of the prior art have a number of disadvantages:

- they are difficult to implement continuously and do not correspond to the requirements of industrialization

the temperature required by the first step, around 30 ^° C., may be favorable to the proliferation of the bacterial flora

- obtaining a pre-emulsion requires the use of additives (emulsifiers) or technological ingredients (vegetable oil)

the restructuring of the fibers, resulting from a three-dimensional reorganization of the protein network, is impossible or antagonistic to the production of a more or less expanded foam. DETAILED DESCRIPTION OF THE INVENTION

The present invention is described in detail below.

The advantageous implementation of the invention resides, in a first phase, in the possibility of using one or more raw materials of halieutic origin, selected from the group of fish, shellfish or crustaceans, either separately or in an intimate mixture .

In a preferred application of the invention, the ground meat used, called stabilized pulp, is obtained, in a first step, by differential mechanical separation, as a function of a material density gradient, of the constituent elements of a raw material. previously cleared of inedible parts such as head and viscera.

The broyate then obtained, composed mainly of sarcoplasmic proteins, myofibrillar proteins, water and lipids, undergoes a series of treatments whose purpose is to eliminate the pro-oxidant compounds naturally contained in the flesh of the products of halieutic origin, as well as the components likely to interfere with the myofibrillary proteins during the final texturing step by obscuring the protein re-attachment sites.

In a preferred application of the invention, the ground material obtained by differential mechanical separation, will be washed, dewatered, deodorized and dehydrated so as to obtain a pulp so-called stabilized pulp.

This stabilized pulp, the raw material of the present invention, will or will not be frozen before transformation, with or without the addition of cryoprotectants.

It will be noted that this so-called stabilized pulp does not correspond to what is commonly referred to as surimi-base in that the successive steps of separation and purification do not lead to obtaining a hydrated concentrate of exclusively myofibrillar proteins. nor to obtain a granular dry product devoid of hydrophilic properties, but to a material having retained all its rheological capabilities of subsequent re-texturing despite production yields greater than 45% from the whole raw product.

In a preferred application of the invention, the stabilized pulp will be introduced into a series of apparatus arranged in line comprising, totally or partially, a vacuum pusher, a co-rotating twin-screw extruder, a counterpressure valve, a forming and pre-cooking die and a steam / microwave combi steamer.

In a preferred application of the invention, this stabilized pulp will be introduced into a vacuum pusher for regulating the feed of a thermoregulated co-rotating bis-screw extruder.

In this configuration, the extruder will be composed of a sleeve including two co-rotating screws and provided at its end with a counter-pressure valve.

According to a preferred embodiment of the invention, the sheath of the extruder will be composed of several juxtaposed elements within which will circulate a brine glycol refrigerated so as to control the temperature increases of the pulp, ci introduced, caused by mechanical heating resulting from kneading mechanisms, shearing and compression.

Specifically, the extruder will have the ability to perform, for a short period of time, steps such as transport, compression, mixing, mixing, shearing, heating, swelling and shaping, depending on the desired effects on the extruder. the treated material.

The factors that determine the characteristics of the extruder are essentially related to the profile of co-rotating screws which are composed of interchangeable elements each having a very specific function.

In a preferred application of the invention, the use of a vacuum pusher upstream of the extruder will allow:

- to ensure feeding of the extruder with stabilized pulp free of air

- To regulate the feed rate of the extruder and consequently the intensity of the texturing as a function of the back pressure applied at the outlet of the barrel of the extruder.

A preferred application of the invention will retain the implementation of pressure sensors on each segment of the barrel of the extruder so as to be able to characterize the intensity of the mechanical effects exerted on the pulp.

In a preferred application of the invention, the profile of the co-rotating screws of the extruder will comprise, in the following order, or in an order determined according to the desired textural characteristics of the finished product:

- a loading area

- a mixing zone of the pulp

- a shear zone a reverse pressure zone by reversing the pitch

- a relaxation area

- a transport area

The loading area will consist of screw elements having a direct and progressive pitch ensuring regular feeding and loading of the extruder.

The mixing zone will have the purpose of perfecting the homogenization of the stabilized pulp. This homogenization may be more or less advanced depending on the desired appearance of the finished product.

The purpose of the shear zone is to micro-dilacerate the stabilized pulp so as to increase the potential number of protein reticlimb sites by forming a continuous and ordered three-dimensional network.

The shear intensity will be controlled, in addition to the value of the inflow given by the vacuum pusher and the length and the specific profile of the elements of the screw, by the pressure applied to the pulp within the following zone constituted by screws with reverse pitch causing a reflux of the material and a tamping plug.

The organization of sub-zones of destructuring coupled with an adequate cooling (T ⁰ <8 ⁰ C in the mass) will ensure a maintenance of the functional properties of the proteins by limiting the phenomenon of micro-heating which occurs in the technologies of the prior art. cutterage type.

The relaxation zone, where the screw elements will be the "kneaders" type, will have the purpose of individualizing the preceding zones and supplying the next transfer zone by creating, within the extruder, a depression of which the intensity will be adjusted according to the backpressure applied by a control valve located at the axial end of the sleeve.

The transfer zone, where the screw elements will be in direct pitch, will have the purpose of enabling the pulp to be conveyed to the exit die, avoiding the flow oscillations that may occur in the expansion zone because of the principle of operation of the mixing discs.

In a preferred application of the invention, the loading zone will comprise several material injection inputs, so as to allow the parametric and simultaneous addition of different ingredients intended to modify the organoleptic appearance of the finished product. A mixture of additives mentioned above means the optional addition of one or more substances or substances to the stabilized pulp in order to adjust its moisture content, hardness, color, taste or cohesion, and to provide as a result, the finished product has the desired texture, flavor and flavor.

Examples of mixing additives described above include soy products and / or vegetable proteins of wheat origin such as whole soybean, defatted soybean or flour, soy protein meal, gluten wheat; the yeast ; starch such as potato starch or cornstarch; cereal flour such as wheat flour and rice flour; milk, milk powder, casein, egg albumen, vegetables and fruits.

These mixing additives can be used alone or in combination.

As described above, the use of the mixing additives is optional. Their assortment and mixing ratios are also variable and adjustable by the operator. When used, they act as a moisture adjuster, hardness adjuster or binder for pulps with a high moisture content, and provide the mouthfeel, flavor, elasticity, flavor and color suitable for finished products sought.

In addition, powdered or liquid additives such as seasonings, spices, flavor enhancers, thickeners and dyes may be optionally employed in the presence or absence of such blending additives.

The mixture of these additives within the stabilized pulp can be produced beforehand within a kneader, but, a preferred application of the invention will retain a parameterizable incorporation of these ingredients within the loading zone of the extruder. .

In a preferred application of the invention, the mixing zone will be composed of a series of flat-profile screw elements ensuring a more or less intimate mixing of the constituent elements of the stabilized pulp, with or without the addition of one or more ingredients. The number of these kneading elements and the induced length of the mixing zone will be determined according to the desire of the operator to have a finished product of more or less homogeneous appearance.

In a preferred application of the invention, the relaxation zone will be composed of two subunits:

- a transfer area

- a zone of proliferation The transfer sub-unit will be characterized by elements of direct pitch screws ensuring conveying of the pulp and inducing a pressure reduction, previously caused by the elements of the backpressure zone, or even a slight depression allowing incorporation of a gas and / or air.

In a preferred application of the invention, the injection of air and / or gas will be carried out at a pressure greater than the pressure existing in the following subunit of expansion and in sufficient quantity to ensure a subsequent expansion of the product. The amount of gas injected is controlled and regulated so as to obtain more or less abundant finished products.

In the following sub-unit of expansion, the screw elements will be kneader type ensuring the incorporation of gas and / or air within the pulp reduced to pasty state, as well as a micro- homogenization and a proliferation of the product. These two actions are highly dependent on the pressure inside the expansion zone, so it will be precisely regulated using a back pressure valve located at the axial end of the sleeve of the extruder.

In another application of the invention, this depression zone will be equipped with a system for incorporating solid compounds in order to obtain inclusions within the protein matrix constituted by the stabilized, textured pulp and more or less abundant.

These inclusions, of size and texture adapted to the wishes of the operator, will be introduced at the level of the depression zone by a controlled rate pusher device.

By the only action of the conveying screws of the subsequent transport zone, these inclusions will be intimately mixed with the textured pulp, without their being dilacerated.

In the present specific application of the invention, these inclusions will consist of particles of a density greater than that of the textured pulp and may be made from surimi paste, vegetables or any other food product of interest. for the operator. These inclusions, prepared online or not, in parallel with the operations concerned by the present invention, may have variable shapes and colors and have been added or not extracts modifying their flavor and flavor in opposition to the characteristics of the protein matrix coating.

An advantageous implementation of the invention provides for the use, at the outlet of the extruder barrel, of a configurable back pressure valve arranged in such a way as to precisely regulate the pressure within the expansion zone. Correlatively to the feed parameters of the extruder by the vacuum pusher, the speed of rotation of the screws and the profile of its constituent elements within the expansion zone, the restriction of the product will be adjusted by this pressure valve so that, if a flow difference is recorded between the inlet and the outlet of the extruder, a regulation can be carried out so as to restore the equality between the flows and ensure a constant and regular work to the inside the sheath of the extruder.

In a preferred application of the invention, the product obtained at the outlet of the extruder, composed of textured stabilized pulp, added or not additives and inclusions may be immediately heated to undergo thermal coagulation.

Conventional heating systems using steam, electricity, gas or the like can be used as heating apparatus for heating the product described above. Batch processing or a continuous process may be employed provided that thermal coagulation and pasteurization of said product can be effected.

In a preferred application of the invention, the heating device is composed of a die inserted in a double closed chamber in which is circulated steam at a temperature adjustable. This gentle heating device allows a progressive coagulation of the protein matrix, without excessive cooking, so that the flow within the cooking die can be done in a fluid manner.

An advantageous implementation of the invention will retain that this heating die can, simultaneously with protein coagulation, be used as a forming die so as to have a finished product of section and shape adapted to the wishes of the customer. 'operator.

At this stage of the process of the invention, one will retain the possibility of obtaining a textured product having a more or less fibrous structure and more or less abundant, stable to pasteurization and sterilization heat treatments, without additions of additives or ingredients specific to this type of properties.

Thus, according to the present invention, using a stabilized pulp comprising one or more raw materials of halieutic origin, selected from the group of fish, shellfish or crustaceans according to the economic or commercial interest of the operator, or comprising a mixture of these raw materials and additives, it is possible to obtain a textured food product, stable to heat treatments, whose organoleptic aspects can be adapted and differ from those of the raw material used. In addition to these innovative aspects described above, the advantage of this method lies in the possibility offered to be able to perform all operations online and continuously, industrially, without having to carry out preliminary phases of premixing hot for incorporation of additives or ingredients

Another innovative interest of the invention resides in the possibility of producing a more or less expanded pulp or foam without the prior formation of an emulsion.

SCHEMATIC OF THE INVENTION

The various essential aspects of the invention will be taken up one by one and explained later, but the invention will first be well understood from the description of the example which follows, given with reference to the boards of attached drawings in which:

FIG. A is a block diagram giving the functional diagram of the processing of the raw raw material allowing the production of raw pulp.

- Figure B is a block diagram giving the block diagram of the treatment of the raw pulp for the production of stabilized pulp

FIG. C is a block diagram giving the functional diagram of the treatment of said stabilized pulp for the production, according to the invention, of a textured finished product, or of a foam, more or less abundant and stable to the treatments. thermal.

The method will now be described with reference to Figures A ₁ B and C (unless expressly indicated otherwise), in chronological order of the operating steps (or phases) that constitute it.

Although particularly studied for fish processing and recovery, this method, which is the subject of the invention, is applicable to any type of fish product, be it shellfish or crustaceans, provided that their flesh contains a certain amount of fish. significant amount of myofibrillar proteins capable of forming a protein gel after texturing and / or agglomeration by physical or chemical methods.

Synoptic A:

Phase 1: Etching and evisceration

Although not constituting an essential element of the present invention, nor the object of any of the resulting claims of the present invention, it is stated that the fish ^Integers (A1) Fresh or thawed, used as material crude base are introduced into a mechanical system (101) for an effective separation of the head and viscera, or are processed manually, so as to not retain than the usual edible part (A2).

Phase 2: Production of raw pulp

The headless and eviscerated fish (A2) are introduced into a mechanical separator (102) constituted by an endless conveying screw with variable pitch, then in the heart of a perforated cylindrical sieve allowing a gradual separation of the constituent elements of the material introduced as a function of a density gradient.

During this differential mechanical separation, the washing water (A3) will be injected (103) into the separation tool, the pH and hardness of which will be adjusted so as to solubilize the compounds of the oxidants present in the flesh as well as the sarcoplasmic proteins responsible for subsequent interactions with the myofibrillar proteins constituting the matrix of the finished products object of the present invention.

At the end of this mechanical separation (102), it will be recovered, on one side a so-called raw pulp (A4) and another dry crushed skin and edges (A5).

Synoptic B:

Phase 1: Washing the raw pulp

Although not constituting an essential element of the present invention, nor the object of any of the resulting claims of the present invention, it is stated that the raw pulp (A4) is introduced into a wash tub (104) where said raw pulp is stirred in the presence of washing water (B1) so as to continue the solubilization mechanisms of undesirable compounds.

Phase 2: Spinning

At the end of this washing (104), the hydrated pulp (B2) will be introduced into a wringer (105) whose object will be to eliminate the proportion of washing water (B3) containing the compounds Solubilized undesirable substances.

Phase 3: Dynamic mixing

So as to perfect the solubilization of certain lipid compounds harmful to the subsequent operations of protein reticlings, the previously washed pulp (B4) will be introduced within a dynamic mixer (106) in the presence of wash water (B5) whose pH and hardness will be similarly adjusted. A deoiled hydrated pulp (B6) will be obtained.

Phase 4: Deodorization

This hydrated and deoiled pulp (B6) will be introduced into a deodorization tank (107) where it will be carried out, by vacuum extraction, the elimination of volatile aromatic compounds (B7) responsible for the flavor of the flesh of fish.

Phase 5: Dehydration

The hydrated pulp, deoiled and deodorized (B8) obtained, will then be introduced into a centrifugal decanter (108), or possibly within a screw press, so as to obtain a so-called stabilized pulp (B9) having a moisture content less than 85%.

Phase 6: Freezing

This stabilized pulp (B9) will then optionally be frozen (109) with or without the addition of cryoprotectants (B10).

Synoptic C:

Phase 1: Feeding the Extruder

The first step of the method that is the subject of the present invention consists in introducing the stabilized pulp (B9) into a vacuum pusher (110).

It is specified that this stabilized pupa (B9), consisting of washed, purified and dehydrated meat of any of the fishery products consisting of the group of fish, molluscs or crustaceans, has been previously thawed as long as the operations of production of stabilized pulp and texturing is not done continuously.

The vacuum pusher (110) must have a quantifiable sequential thrust system and consist of two co-penetrating Archimedean screws and a vacuum stage downstream of a supply hopper.

The stuffing sequence and the amount of product transferred by stuffing sequence can be parameterized, thus characterizing the instantaneous flow rate or the weighted flow rate at the outlet of the pusher, as a function of the regulation instructions specific to the operation of the extruder described below. . The stabilized pulp (C1) obtained at the pusher outlet (110) will be free of air.

Phase 2: Loading the Extruder

In a preferred application of the invention, the extruder (111) is of co-corrative bis-screw type consisting of a sleeve in which are driven two co-penetrating screws rotating in opposite directions.

The two screws consist of a splined shaft supporting interchangeable elements having various functions. In a preferred application of the invention, the profile of the screws will comprise, in the following order, or in a different order determined by the operator according to the desired textural characteristics of the finished product:

- a loading area (111.A)

- a mixing zone (111.B)

a shear zone (111.C)

- a back pressure zone (111.D)

- a relaxation area (111.E)

- a transport zone. (111.F)

According to a preferred embodiment of the invention, the sheath of the extruder (111) will be composed of several juxtaposed elements inside which will be circulated a brine glycol (C.13) and a system thermoregulation (112) so as to control the temperature increases of the pulp, ci introduced, caused by the mechanical heating resulting from mixing mechanisms, shearing and compression. A preferred application of the invention will retain that the temperature at the heart of the injected product should not be greater than 8 ° C so as to avoid protein denaturation or a setting of the product in the sheath.

Specifically, the extruder (111) will have the ability to perform, for a short period of time, such steps as conveying, compressing, mixing, kneading, shearing, heating, swelling, and shaping, as desired. desired effects on the treated material.

The stabilized pulp (C1) will be conveyed by the pusher into the loading zone (111.A) of the extruder (111) by an airtight piping system.

The loading zone (111.A) will be composed of direct and progressive step screw elements ensuring a regular and continuous loading of the extruder. In a preferred application of the invention, the loading zone will comprise several material injection inlets (112.A; 112.B; ...) so as to allow the parametrible and simultaneous addition of different ingredients (C2; C3; ...) intended to modify the organoleptic aspect of the finished product. A mixture of additives mentioned above means the optional addition of one or more substances or substances to the stabilized pulp in order to adjust its moisture content, hardness, color, taste or cohesion, and to provide hence the effect on the finished product the desired texture, flavor and flavor.

These mixing additives (C2; C3; ...) can be used alone or in combination.

In addition, powdered or liquid additives such as seasonings, spices, extenders (flavor enhancers), thickeners and dyes may be optionally employed in the presence or absence of such blending additives.

The mixture of these additives within the stabilized pulp can be produced beforehand within a kneader, but, a preferred application of the invention will retain a parameterizable incorporation of these ingredients within the loading zone (111.A. ) of the extruder.

In another preferred application of the invention, the loading zone will be provided upstream with a flowmeter (113.a) for measuring the precise amount of pulp introduced into the sheath of the extruder (111). A specific application will retain that this flow measurement can be achieved by recording the characteristics of pushing sequences of the vacuum pusher (110). The product obtained (C4) at the outlet of the loading zone (111.A) will be a stabilized, air-free pulp mixed with heterogeneous mixture additives (C2; C3; ...).

Phase 3: Mixing the product

The pulp (C4) will be conveyed by the screws of the extruder (111) to a mixing zone (111.B) whose purpose will be to perfect the homogenization of the pulp and possibly the pulp with the mixing additives ( C2; C3; ...)

This homogenization may be more or less advanced depending on the desired appearance of the finished product.

The product obtained is an air-free pulp (C5), with or without addition of mixing ingredients (C2; C3; ...) and more or less homogenized.

Phase 4: Shearing the product

The pulp (C5) will be conveyed by the screws of the extruder (111) to a shear zone (111.C) whose purpose will be to micro-dilacerate the stabilized pulp so as to increase the potential number of reaction sites. protein clashes by forming a continuous and ordered three-dimensional network.

The shear intensity will be controlled, in addition to the value of the inflow given by the vacuum pusher (110) and the length and the specific profile of the elements of the screw, by the back pressure applied to the pulp within the next zone (114.D) consisting of screws with reverse pitch causing a reflux of the material and a tamping plug.

The organization of sub-zones of destructuring coupled with an adequate cooling (T ° <8 ° C in the mass) will ensure a maintenance of the functional properties of the proteins by limiting the phenomenon of micro-heating which occurs in the technologies of the prior art cutterage type.

The product obtained (C6) is an air-free pulp, added more or less intimate with mixing ingredients (C2; C3; ...) and more or less micro-dilacerated. Phase 5: Pressurization of the product

The pulp (C6) will be conveyed by the screws of the extruder (111) to a backpressure zone (111.D) whose purpose will be to create a tamping plug allowing a rise in pressure of the melee.

This back pressure will be generated thanks to the specific profile of the screws which will have an inverted or indirect pitch.

Depending on the number of elements of the screw at this level and the induced length of the backpressure zone (111.D), the efficiency of the shear (111.C) can be modulated.

The product obtained (C7) is an air-free pulp, added in a more or less intimate manner of mixing ingredients (C2; C3; ...) and more or less micro-dilacerated.

Phase 6: Relaxation of the product

The pulp (C7) will be conveyed by the screws of the extruder (111) to an expansion zone (111.E) whose purpose will be to individualize the preceding zones and supply the transfer zone (111.F) by creating, within the extruder, a depression whose intensity will be adjusted according to the back pressure applied by a control valve (113) located at the axial end of the sleeve.

In a preferred application of the invention, the relaxation zone (111.E) will be composed of two subunits:

a transfer zone (111. E1)

- an expansion zone (111. E2)

The transfer sub-unit (111.E1) will be characterized by direct-pitch screw elements ensuring conveying of the pulp (C7) and inducing a reduction in pressure, previously caused by the elements of the backpressure zone. (111.D), or even a slight depression allowing the incorporation of a gas and / or air (C10).

In a preferred application of the invention, the injection of air and / or gas will be carried out at a pressure greater than the pressure existing in the following expansion subunit (111.E2) and in an amount sufficient to ensure subsequent expansion of the product. The amount of gas injected (C10) is controlled and regulated so as to obtain more or less abundant finished products.

In the following sub-unit of expansion (111.E2), the screw elements will be kneader type ensuring the incorporation of gas and / or air (C10) within the pulp (C7) reduced to the state of pasty material, as well as micro-homogenisation and product proliferation.

These two actions are highly dependent on the pressure inside the expansion zone (111.E), so it will be precisely regulated using a back pressure valve (113) located at axial end of the barrel of the extruder.

In another application of the invention, this zone of depression

(111.E) will be equipped with a system of incorporation of solid compounds (C11) in order to obtain inclusions within the protein matrix constituted by the stabilized pulp, textured and more or less abundant.

These inclusions (C11), of size and texture adapted to the wish of the operator, will be introduced at the level of the zone of depression

(111.E2) by a controlled rate pusher device.

By the action of the conveying screws of the subsequent transport zone (111.F), these inclusions will be intimately mixed with the textured pulp, without their being dilacerated.

In the present specific application of the invention, these inclusions (C11) will consist of particles of a density greater than that of the textured pulp (C7) and may be made from surimi paste, vegetables or any other food product of interest to the operator. These inclusions, prepared online or not, in parallel with the operations concerned by the present invention, may have variable shapes and colors and have been added or not extracts modifying their flavor and flavor in opposition to the characteristics of the protein matrix coating.

The product obtained (C8) is a more or less expanded pulp, more or less intimate addition of mixing ingredients (C2; C3; ...) and / or inclusions.

Phase 7: Transfer of the product

The pulp (C8) will be conveyed by the screws of the extruder (111) to a transport zone (111.F) whose purpose will be to allow the pulp to be conveyed to the outlet die (114) by dispensing flow oscillations that can occur in the expansion zone (111.E) due to the operating principle of the mixing discs.

The screw elements of the transport zone (111.F) will be in direct pitch.

The product obtained (C9) is a more or less expanded pulp, added more or less intimate mixing ingredients (C2; C3; ...) and / or inclusions and conveyed at a constant rate. Phase 8: Pressure regulation

It will be disposed at the axial outlet of the barrel of the extruder (111) a counter-pressure valve (113) whose purpose will be to regulate the pressure within the expansion zone (111.E).

In correlation with the feeding parameters of the extruder by the vacuum pusher (110), the speed of rotation of the screws and the profile of its constituent elements within the expansion zone (111.E), the restriction of the product ( C9) will be adjusted by this backpressure valve (113) so that, if a flow difference is recorded between the inlet and the outlet of the extruder, regulation can be effected so as to restore the equality between the flows and ensure a constant and regular work inside the sheath of the extruder.

A mass flow meter (113.b) will be disposed downstream of the back pressure valve (113) to measure the outflow compared to the incoming flow measured at the inlet of the extruder by the flow meter (113.a).

The product obtained (C12) is a more or less expanded pulp, added more or less intimate mixing ingredients (C2; C3; ...) and / or inclusions and conveyed at a constant rate.

Phase 9: Forming and pre-cooking

It will be disposed at the outlet of the counter-pressure valve (113) a forming die and pre-cooking (114) allowing progressive coagulation of the protein matrix and its simultaneous forming.

An advantageous implementation of the invention will retain that this heating die can, simultaneously with coagulation protein, be used as forming die so as to have a finished product of section and shape adapted to the wishes of the operator.

The product obtained (C14) will be a textured pulp, more or less abundant, more or less intimate addition of mixing ingredients (C2; C3; ...) and / or inclusions and shaping

These finished products (C14) may be packaged as they are in vacuum or modified atmosphere trays as fresh or semi-fresh products, or they may be canned, with or without the addition of lapping sauce.

As already pointed out, the invention finds a privileged application in the field of the industrial recovery of fish flesh, but it remains generally applicable to the processing of any type of fish product, be it molluscs or crustaceans, provided that their flesh contains a significant amount of myofibrillar proteins capable of forming a protein gel after texturing and / or agglomeration by physical or chemical methods.

It goes without saying that the invention can not be limited to this example, but that it extends to multiple variants or equivalents to the extent that its definition given in the appended claims is respected.

Claims

What is claimed is:

1 - Process for the production by cold extrusion of foamed foodstuffs, stable to heat treatment, with or without inclusions, from stabilized pulp of products of halieutic origin comprising the succession of the following steps taken in this order: a pulp is prepared stabilized pulp (B9) is introduced this stabilized pulp within a vacuum pusher (110) for feeding a cold-heat-cooled co-rotating bis-screw extruder (111) is carried out a succession of kneading, shearing, swirling and transfer operations within the extruder and then introducing the product into a forming and precooking die (114)

2 - Process according to claim 1 characterized in that the stabilized pulp (B9) is a hydrated compound of proteins of halieutic origin whose production yields, from the whole raw product, is greater than 45%

3 - Process according to claims 1 and 2 characterized in that said stabilized pulp (B9) can be frozen, with or without cryoprotectants, before use.

4 - Process according to claim 1 characterized in that the stabilized pulp (B9) is introduced into a vacuum pusher (110) having a quantifiable sequential thrust system.

5 - Process according to claim 1 characterized in that the vacuum pusher (110) continuously feeds a co-rotating bis-screw extruder (111)

6 - Process according to claim 1 characterized in that the stabilized pulp (B9) may be added with mixing additives (C2; C3; ..) whose purpose will be to adjust the moisture content, hardness, color, taste and cohesion of the finished product and to provide the finished product with the desired texture, flavor and flavor.

7 - Process according to claim 1 characterized in that the co-rotating screw extruder bis consists of a sleeve in which are driven two co-penetrating screws rotating in opposite directions and comprising, in the following order or in a different order, several differentiated working areas, namely:

- A loading area (111.A)

- A mixing zone (111.B)

- A shear zone (111.C) - A back pressure zone (111.D)

- A relaxation area (111.E)

- A transport zone (111.F)

8 - Process according to claims 1, 5 and 7 characterized in that the sheath of the co-rotating bis-screw extruder (111) is composed of several juxtaposed elements within which will be circulated a brine glycol chilled in order to control the rise in the temperature of the pulp caused by the mechanical micro-heating resulting from the kneading, shearing and compression mechanisms.

9 - Process according to claims 1, 6 and 7 characterized in that the loading zone (111.A) of the extruder (111) is equipped with direct and progressive step screw elements and one or more injection inlets.

10 - Process according to claims 1, 6 and 7 characterized in that the loading area will be provided upstream of a flow meter (113. a) for accurately measuring the amount of pulp (C1) introduced into the extruder ( 111)

11 - Process according to claims 1, 5 and 7 characterized in that the mixing zone (111.B) is composed of flat profile screw elements ensuring a more or less intimate mixture of the constituent elements of the stabilized pulp (C1 ), with or without one or more mixing ingredients.

12 - Process according to claims 1, 5 and 7 characterized in that the shear zone (111.C) consists of co-penetrating gear-type screw elements ensuring a more or less thorough tearing of the pulp (C5) whose utility is to increase the potential number of protein re-snap sites by forming a three-dimensional and ordered network.

13 - Process according to claims 1, 5 and 7 characterized in that the backpressure zone (111.D) consists of screw elements with reverse or indirect pitch whose utility is to create a tamping plug and to increase the pressure within the sheath in order to modulate the shear effect (111.C)

14 - Process according to claims 1, 5 and 7 characterized in that the expansion zone (111.E) consists of two subunits:

- a transfer sub-unit (111.E1)

- a sub-unit of expansion (111.E2)

15 - Process according to claim 14, characterized in that the transfer sub-unit (111.E1) comprises screw elements with a direct pitch ensuring a conveying of the pulp (C7) and inducing a reduction of the pressure within the sheath of the extruder or even a slight depression allowing the incorporation of gas and / or air (C10)

16 - Process according to claim 14, characterized in that the expansion subunit (111.E2) comprises kneader type screw elements ensuring the incorporation of gas and / or air within the pulp ( C7), as well as a micro-homogenization and a more or less intense proliferation of the product.

17 - Process according to claims 1, 5 and 7 characterized in that the product transfer zone (111.F) consists of screw elements with direct pitch whose purpose will be to allow the conveying of the pulp (C8) to the outlet die (114) by avoiding flow oscillations that may occur in the expansion zone (111.E) due to the operating principle of the mixing discs.

18 - Process according to claims 1, 14, 15 and 16 characterized in that is disposed at the axial outlet of the extruder (111) a configurable back pressure valve (113) for regulating the pressure within the expansion zone (111.E) and the differential between the inflow and outflow of the extruder.

19 - Process according to claim 18 characterized in that the parameterization of the back-pressure valve is made by differential measurement of the incoming flow, recorded by the mass flow meter (113.a), and the outflow, recorded by the mass flow meter. (113.b)

20 - Process according to claims 1, 14, 15 and 16 characterized in that the depression zone (111.E) can be equipped with a system for incorporating solid compounds (C11) for the purpose of obtaining inclusions within the protein matrix constituted by the stabilized, textured pulp and more or less abundant (C7).

21 - Process according to claim 1 characterized in that a forming die and pre-cooking (114) is disposed at the outlet of the counterpressure valve (113) allowing a progressive coagulation of the protein matrix and its forming simultaneous.

22 - Process according to claim 21 characterized in that the forming die and pre-cooking (114) consists of a die shaped and section adapted to the needs of the operator, inserted into a double-walled enclosure at within which is circulated steam at a temperature modulable.

23 - Installation for the implementation of the method according to claim 1 characterized in that all operations described above are performed online and continuously 24 - Installation for implementing the method according to claim 1 characterized in that the operations described above can be modulated so as to obtain a finished product, more or less textured, more or less fibrous, more or less added ingredients mixing, more or less overrun and more or less added inclusions.

25 - Process according to claim 1 characterized in that the finished finished product obtained has a thermal stability pasteurization treatments or sterilization may be implemented later.

26 - Process according to claim 1 characterized in that the more or less thorough expansion of the product is obtained without adding additives of emu Isification

27 - Process according to claim 1 characterized in that the raw material used consists of stabilized pulp made from one or more products of fish origin, jointly or separately, selected from the group of fish, shellfish or crustaceans as long as their flesh contains a significant amount of myofibrillar protein capable of forming a protein gel after texturing and / or agglomeration by chemical or physical methods.