Extrusion system for processing extruded food products, and method of processing

Abstract

An extrusion system comprising an extruder and a valve (100), configured to extrude a viscoelastic extruded material from the extruder, with the extruded material flowing through the valve at a volumetric flow rate V, said valve having ac onstriction portion (101) comprising at least a first movable portion (102), with across-sectional area C (103) orthogonal to the extruded material flow direction x and a length L along the extruded material flow direction x, moving towards and away from a center axis of the flow channel to vary the opening width, in which the cross-sectional area C varies along the direction x such that |dC / dx| is inferior to 0.03 m and preferably below 0.01 m throughout the entire length of the valve; and the elongation rate to length ratio ε / L is inferior to 100 m-1.s-1, preferably inferior to 50 m-1.s-1 and preferably inferior to 15 m-1.s-1 throughout the entire length of the valve.

Description

[0001] New PCT Application

[0002] Planted Foods AG

[0003] Vossius Ref.: AG4214 PCT BS

[0004] Extrusion system for processing extruded food products, and method of processing

[0005] 5 TECHNICAL FIELD

[0006] The present invention relates to a system and method for manufacturing food products. More particularly to an extrusion system comprising an extruder and a valve for producing extruded viscoelastic product such as food and particularly extruded plant-based food.

[0007] BACKGROUND

[0008] Current meat consumption is depleting natural resources while fuelling climate change. The current world-wide meat consumption is unsustainable and therefore meat alternatives must be developed to counteract the ever-growing consumption of meat and at least partially replace the consumption of conventional meat.

[0009] Various approaches have been applied for the production of meat alternative products resulting

[0010] 15 in relatively large differences in texture and / or nutritional value. For instance, tofu and some more modern products, such as plant-based sausages and / or meat loafs, are produced by gelation of watery dispersions / solutions of proteins and / or polysaccharides. This approach generally results in products which have relatively low protein contents, e.g., less than meat, and / or soft, silky, springy, and relatively juicy textures which lack a degree of fibrosis which is

[0011] 20 comparable to whole cuts or pieces of animal meat, such as from muscle tissue, respectively.

[0012] Meat alternatives which have higher protein content and a fibrous structure are often produced by extrusion. Most of the final properties of meat alternative are developed during this extrusion, making it essential to maintain a continuous throughput of extruded material to ensure the reproducibility of the product's physical characteristics. This is important for dry

[0013] 25 extrusion but is particularly critical for high-moisture extrusion cooking.

[0014] High moisture extrusion cooking or shear cell processing are often used to produce meat alternative similar to chicken. During this process extruded material, comprising proteins, is molten under relatively high temperature, relatively high pressure and at moisture contents of 40-80% and subsequently cooled in a cooling die under shear resulting in the formation of a

[0015] 30 solidified fibrous structure. The meticulous management of extruded flow rates, particularly with regard to the exit of the cooling die, presents a crucial challenge that requires innovative solutions. In most cases the extruded material flow rate is determined by the extrusion rate of the extruder and by the size of the cooling die and only one combination results in a final product with the desired properties. It is therefore not possible to change the flow rate without

[0016] 35 changing the properties of the food product.

[0017] One of the main problems inherent in existing extrusion systems is the complex interplay between adjusting the flow rate and the resulting properties of the final food product. Attempts to alter flow rates via aperture adjustments, such as displacement pumps (i.e. see JPH084487B2, or JPH084488B2) of can inadvertently lead to unintended changes to the intrinsic attributes of

[0018] 40 the final product. Other attempts to reduce the flow rate using mechanical devices such as dynamic aperture deform the flow profile. One example is described in WO2022135732A1, where a dynamic aperture uses this deformation of the flow profile to generate a new product with completely different properties. Another attempt to change the flow rate is described in EP4059357A1 where they use temperature variations to increase or decrease the viscosity of the material before extrusion, leading to long time before reaching an equilibrium again and some difficulties to maintain a constant and reproducible extruded material flow rate. These attempts can compromise the characteristics of the products and the extruded material flow rate is difficult to control finely.

[0019] More generally, extrusion dies, valves or nozzles typically show a constricting cross section area where the extruded material is pushed through. In a constricting flow the extruded material such as polymers or protein rich food material can exhibit non-Newtonian viscoelastic flow behavior. The deformation of such viscoelastic material typically shows transient, meaning timedependent deformation behavior. Viscoelastic materials undergo transient deformation, meaning the shape of the flow profile changes over time in response to the deformation. As illustrated in Fig. 1. the flow of extruded material presents a parabolic flow profile before the constriction that affects the flow profile of the extruded material with the apparition of vortexes and secondary flows before and after the constriction. The flow profile of the extruded materials gradually returns to its original shape after a relaxing time, exhibiting a delayed response to deformation. This relaxation process occurs at varying time scales and impacts the structure and properties of the extruded material and therefore to the food product.

[0020] Due to the high viscosity of the extruded material, relaxation takes a considerable amount of time, while the distance between the constriction area and the cooling of the extruded material can be relatively short. Once the extruded material is cooled, the structure of the extruded material is fixed, as a result, the cooled extruded material reflects the flow modification effects.

[0021] In addition, in the case of dynamic apertures or flow reducers, "dead zones" or vortexes may be present before and / or after the narrowing parts. These dead zones are areas where residual materials accumulate and age. These residual, aged materials can exert a negative influence on the properties of food products but also on the hygienic level because bacteria could develop within these dead zones.

[0022] It is evident that there is a significant need to be able to control and adjust the extruded material flow rate without altering the properties of the food product. The change of the extruded flow rate needs to be relatively fast to limit wastes and a fine adjustment of the extruded flow rate is needed.

[0023] SUMMARY

[0024] The present invention achieves these objectives by proposing a system and a method for producing a food product wherein the production rate or flow rate can be adjusted by the means of a controllable valve that can be closed or open or in any position in between without substantially changing the physical properties of the food product.

[0025] Specifically, this invention relates to an extrusion system employing a valve to regulate the flow rate of extruded material post-extrusion, while maintaining the characteristics of the final food product. The valve is specifically designed to prevent the formation of vortexes or secondary flows within the extruded material as it passes through.

[0026] The system describe herein is an extrusion system comprising an extruder and a valve, configured to extrude a viscoelastic extruded material from the extruder, with the extruded material flowing through the valve at a volumetric flow rate V, said valve having a constriction portion , wherein the constriction portion comprises at least a first movable portion, with a cross-sectional area C orthogonal to the extruded material flow direction x and a length L along the extruded material flow direction x, moving towards and away from a center axis of the flow channel to vary the opening width, characterized in that the cross-sectional area C varies along the direction x such that \dC / dx\ is inferior to 0.03 m and preferably below 0.01 m throughout the entire length of the valve; and the elongation rate to length ratio s / L is inferior to 100 m-1.s-1, preferably inferior to 50 m-1.s-1and preferably inferior to 15 m-1.s-1throughout the entire length of the valve.

[0027] By preserving the integrity of the flow profile post-extrusion, this innovation enables the utilization of the valve to manage throughput of final food product by changing its opening. Sensors are used to measure the throughput, and a feedback loop can be used to maintain the desired flow. The valve can be particularly useful in scenarios where multiple streams with multiple cooling dies are concurrently employed, thus enhancing total throughput while maintaining the desired throughput in all streams.

[0028] The valve described herein can be a pinch valve wherein the extruded material flow in an elastically deformable material and a first and / or a second bar are pinching the elastically deformable material to form the first movable portion and / or the second movable portion, preferably the pinching is done by moving the two bars in opposite direction.

[0029] The extrusion system can comprise a plurality of sensors for measuring the aperture of the valve, the physical characteristics of the extruded material and / or extrusion parameter. Those sensors can be connected to a control feedback loop configured to control the aperture of the valve in response to at least one sensor.

[0030] The extrusion system can comprise a plurality of valves and can further comprise a flow splitter, the flow splitter comprises an entry and a plurality of exits, the entry can be connected directly or indirectly to the extruder to split a flow of extruded material into a plurality of streams, the exits can be each connected directly or indirectly to one of the valves.

[0031] A method to produce a food product using the extrusion system is also described. The method comprising:

[0032] -providing an extrusion system comprising an extruder and a valve describe herein wherein the valve is connected to the extruder;

[0033] -receiving, mixing, and conveying a plurality of ingredients in the extruder to produce an extruded material, the plurality of ingredients including a protein powder, and water;

[0034] -conveying the extruded material to the valve.

[0035] A plurality of sensors and a control feedback loop to control the aperture of valve in response to the at least one product sensor can be used.

[0036] A splitter can be located downstream of the extrusion die and configured to split the extruded material into a plurality of streams, each stream comprising at least one valve with an aperture sensor, one product sensor; and the control feedback loop controlling each valve independently in response to each product sensor of each stream. A cooling die configured to structure the food product can be connected directly or indirectly downstream of each valve.

[0037] BRIEF DESCRIPTION OF THE FIGURES

[0038] In Fig. 1 is represented the flow profiles of extruded material during the passage of a comparative valve.

[0039] In Fig. 2 is represented the flow profiles of extruded material during the passage of a valve according to one embodiment.

[0040] In Fig. 3 is represented the valve according to one embodiment.

[0041] In Fig. 4 are represented the valve according to one embodiment in different states, open Fig. 4a, partially closed Fig. 4b and closed Fig. 4c.

[0042] In Fig. 5 is represented the valve partially closed according to another embodiment.

[0043] In Fig. 6 is represented the food product after the cooling die with the valve according to one embodiment on Fig. 6a, with a valve (comparative) on Fig. 6b and without valve on Fig. 6c.

[0044] In Fig. 7 is represented an extruder, a splitting flow device, two valves and two cooling dies according to another embodiment.

[0045] In Fig. 8 is represented a valve in a cooling die according to another embodiment.

[0046] DETAILED DESCRIPTION

[0047] The present invention comprises an extrusion system with a valve placed after the extruder, said valve having the purpose of controlling the flow rate of the extrudate without creating secondary flows, such as represented in Fig. 2. In this figure most of the deformation of the flow profile of the extruded material happens over a distance substantially equal to the constriction length applied by the valve without any secondary flows or vortexes.

[0048] The extrusion system includes one or more feeders which supply one or more respective ingredients to an extruder which includes one or more rotating screws which are disposed and rotatable within a stationary barrel.

[0049] The extruded material can be of any type of viscoelastic material such as plastic, polymers, elastomers, caoutchouc, proteinaceous material and / or food ingredients, etc.

[0050] Foods ingredients may include, for example, one or more alternative protein powders for example, plant-based flours, water, oil, and may also include additives, fillers, processing aids, and the like. The one or more feeders introduce the ingredients into the extruder. The extruder mixes and advances the ingredients and extrudes an extruded material through a die. The extruded material may then undergo one or more post-processing operations to transform the extruded material exiting the die into a final product that can be a food product and / or a meat substitute product.

[0051] Any kind of extrusion systems can be used such as but not limited to single-screw extrusion, double-screw extrusion, cold extrusion, hot extrusion, high moisture extrusion or dry extrusion.

[0052] The extrusion system can be a wet extrusion system to produce food products with a fibrous structure created by wet texturization. Wet extrusion systems can be high moisture extrusion cooking or shear cell processing. Wet texturization means that a protein-containing formulation is mixed with a water phase, preferably subjected to a temperature of above 100°C under shear, followed by cooling under shear which results in the formation of a fibrous structure. Wet texturization, in particular, refers to texturization at a water content of 40-80 wt%. Remarkably, in wet textured food products, the fibers are substantially aligned due to the controlled cooling and solidification under a specific flow profile, which can be of particular importance for the present invention. As the material flows through pipes and / or the cooling die, a velocity gradient forms due to thermal conduction. This gradient results in a parabolic flow profile, where the extruded material's center moves faster than its periphery, influencing the product's physical properties, such as fibrosity.

[0053] The outer side of the extruded material, in contact with the pipe or cooling die, moves slower than the central portion due to thermal conduction from the pipe. Consequently, this creates a parabolic flow profile, which plays a crucial role in determining the physical properties of the meat substitute product, including its fibrous texture. The current innovation incorporates a flow rate controlling valve positioned after the extrusion and before the cooling die to adjust the extruded material's flow rate without altering the parabolic flow profile shape.

[0054] Wet textured food products are preferably produced by high moisture extrusion cooking in an extruder, more preferably in a twin-screw extruder, at a moisture content of above 40 wt% and below 80 wt%, even more preferably between 45 wt% and 70 wt%, and at a protein content of above 10 wt%, preferably above 15 wt%, even more preferably above 20 wt%. In particular, the mixture of protein, water and other components is sheared and heated in the extruder to above 100°C, preferably above 120°C and subsequently cooled in a cooling die to below 100°C before exiting the machine to avoid puffing and form a fibrous structure.

[0055] The term "fibrous structure" refers to a structure in which aggregated high aspect ratio elements or "fibers" and / or fiber sheets, in particular consisting of proteins, result in anisotropy characteristics regarding structure and mechanical properties of the fibrous structure. Preferably, the fibrous structure has a high degree of alignment in one direction defined by the flow profile. The fibrous structure is formed in the wet texturization process as proteins and other components are stretched and / or aligned by application of shear. The fibrous structure is comprised of multiple fiber bundles, aggregated fibers, and / or fiber sheets, sometimes referred to as "fibers".

[0056] Alternatively, the extrusion system can be a dry extrusion system to produce food products with a porous structure. Dry extrusion system is a system by which a pressurized molten protein mixture exits the extruder; the sudden drop in pressure causes rapid expansion into a porous structure. This porous structure provides pores or channels.

[0057] The proteins incorporated in the extruder can be from one protein source. Alternatively, proteins comprise pea protein and at least one other protein source, preferably from plants. Alternatively, the proteins can be from at least peas, sunflowers and oats. Alternatively, the proteins can be from at least pea and yeast. Alternatively, the proteins can be from at least pea and soy. Alternatively, the proteins can be from soy as the only protein source. Alternatively, the proteins can be from pea as the only protein source.

[0058] The valve used with this extrusion system is controlled to regulate the flow rate of the extruded material passing through it. The valve is configured to receive extruded material from the extruder, with the extruded material flowing through the valve at a volume flow rate V = — , with V a volume of extruded material, along the flow direction x being the flow direction of the extruded material.

[0059] The valve has a constriction portion of variable opening width. The constriction portion is made of any deformable materials such as plastic or caoutchouc that can deform without breaking. The constriction portion can have any shape as long as the variation of the cross section C of the constriction portion along the flow direction x is changing smoothly, without sudden variation such as \dC / dx\< is inferior to 0.03 m and preferably below 0.01 m throughout the entire length of the valve. The constriction portion comprises at least a first movable portion moving towards and away from a center axis of the flow channel to vary the opening. The movable portion is the part of the constriction portion that is deformed to reduce the flow rate of the extruded material. The deformation can be done by any possible way placed inside the constriction portion for example with the use of piezoelectric devices, contracting under the effect of electrical voltage, inclusion of magnetic materials in the constriction portion that will move under magnetic field. Alternatively, an actuator positioned adjacent to the constriction portion applying pressure.

[0060] In one embodiment presented in Fig. 3, the valve 100 present a constriction portion 101 of variable opening width, wherein the constriction portion comprises a movable portion 102 that can move towards and away from a center axis of the flow channel to vary the opening width of the valve. The constriction portion presents a cross-sectional area C 103 varying along the direction of the extrudate flow material direction x.

[0061] In operation, the material flows from extruder through the valve. The movable portion of the valve can be adjusted by any means such as actuator mechanisms to vary the size of the aperture through which the extruded material passes. By controlling the aperture size, the flow rate of the extruded material can be precisely regulated.

[0062] The invention presented herein shows a moderate variation in cross section C along a direction orthogonal to the material flow direction x. Due to the viscoelasticity of the extruded material, it is only possible to maintain a laminar flow through the valve only if the variation of the cross- sectional area C along the extrudate flow material direction x remain small i.e. \dC / dx\\s inferior to 0.03 m and preferably below 0.01 m throughout the entire length of the valve. It is also mandatory to consider the volumetric flow rate V of the extruded material in the valve. We can define the elongational rate e (Luger et al. 2019):

[0063] . _ V 1 dx dC wherein V is the volume flow rate of a cross-section C of the extruded material. To take into account the geometry of the valve, the inventor has discovered that the ratio of the elongation rate to the length e / L should be kept as low as possible. Indeed, due to the viscoelasticity of the extruded material, the more the extruded material is elastic the longer the movable portion of the valve needs to be. Therefore, the elongation rate to length ratio e / L is inferior to 100 m-1.s-1, preferably inferior to 50 m-1.s-1and preferably inferior to 15 m-1.s-1throughout the entire length of the valve to maintain a laminar flow without vortexes.

[0064] The movement of the movable part can be done in order to have the elongation rate to length ratio e / L is inferior to 100 m-1.s-1, preferably inferior to 50 m^.s^and preferably inferior to 15 nr1.s1throughout the entire length of the valve at all time to maintain a laminar flow without vortexes. Such valves can be used with different devices such as any kind of pipes, flow control device, cooling die, flow distributors such as splitters and / or extrusion cone and can be located before, after and / or before and after in such devices.

[0065] In one embodiment the valve is located directly or indirectly after the extruder to produce porous products. "Directly" means that the valve is connected to the extruder without pipe or any device between them and, on the contrary, "indirectly" means that a pipe or other devices or tools are connected between the extruder and the valve.

[0066] In another embodiment the valve is connected directly or indirectly after the extruder and directly or indirectly before a cooling die.

[0067] In Fig. 4a is represented a valve 200 according to one embodiment comprising a constriction portion 201, an inlet end attached to an upstream pipeline and an outlet end attached to a downstream pipeline, two bars 204 positioned adjacent to the constriction portion 201. The valve is configured to circulate extruded material from the upstream pipeline to the downstream pipeline. The valve is controlled to constrict the constriction portion 201 to adjust the extruded material flow rate passing the valve 200. The constriction portion 201 being open has a maximum opening substantially equal to the inner cross section of the upstream pipeline.

[0068] The extruded material flow rate is determined by the amount of extruded material passing through the constriction portion per time unit. As the volume and mass of material passing through this section maintain a direct relationship, both aspects can be used indifferently in this description.

[0069] Fig. 4b presents the valve 200 where the constriction portion 201 is partially closed, reducing the extruded material flow rate passing through the valve 200. The aperture of the valve is defined by the opening of the constriction portion 201 when a force is exerted by the two bars 204 on the constriction portion 201. The constriction portion 201 gradually flattens under the applied force, reducing the internal passage height and therefore reducing the passage of extruded material through the valve 200. The valve 200 can have an aperture comprised between closed and fully open. During this constriction, the constriction portion 201 is deformed by the action of two convex bars 204. In this embodiment the constriction portion 201 comprises a narrowing zone 207 where the material flow is constricted before an expansion zone 208 where the material flow is decompressed before the outlet end. The narrowing zone 207 presents a moderate decrease in cross-sectional area. The expansion zone 208 exhibits a moderate increase of the cross-sectional area. The moderate increase of the cross-sectional area in the expansion zone 208 can be the opposite of the moderate decrease of the cross-sectional area in the narrowing zone 207 or it can be different. The shape of the narrowing zone 207 and / or the expansion zone 208 can follow any mathematical function such as polynomial, tangent, hyperbola tangent, exponential and / or logarithm. The movable portion being the sum of the narrowing zone 207 and the expansion zone 208.

[0070] The aperture of the valve 200 can be fully open with the maximum aperture presented in Fig. 4c, closed with an aperture equal to 0 presented in Fig. 4a, or partially closed presented in Fig. 4b.

[0071] The valve 200 being open shouldn't substantially affect the flow profile structure of the extruded material through the valve 200. In other words, when bars 204 does not apply any force on the constriction portion 201, the flow profile of the extruded material shouldn't change substantially. The constriction portion 201 is made of a material that can be pinched without breaking such as plastic, rubber, or any other suitable elastically deformable materials. For use in food production, the valve's inner surface should meet the necessary standards for being food grade. Also, the inner surface of the valve should be substantially smooth to not alter the flow profile close to the inner surface of the valve.

[0072] The two bars used to compress the constriction portion 201, can have any shape such as a cubic, cylindrical or any other shape. In one embodiment presented in Fig.4a to Fig.4c the bars are semi-cylindrical or convex. In another embodiment, bars have a specific design and geometry to specifically shape the narrowing zone 207 and / or the expansion zone 208.

[0073] Bars can be used to exert pressure on the constriction portion 201, employing a diverse range of methods such as but not limiting to the utilization of actuators, pneumatic systems, magnetic forces, hydraulic mechanisms, manual force application, servo motors, and / or robotic automation. Additionally, sensors can be used to measure the bar position and therefore used to automatically control the pinching mechanism in a closed loop system for example.

[0074] In one embodiment presented, in Fig. 5, the bars 304 are cubic and the movable portion comprises a narrowing zone 307 where the material flow is constricted before a resistance zone 309. The resistance zone 309 has a substantially equal opening and the extruded material flows without substantial disturbance of the flow profile until an expansion zone 308 where the material flow is decompressed before the downstream pipeline. The aperture of the valve can be fully closed, fully open or partially closed.

[0075] In one embodiment the material used is flexible enough to create a resistance zone 309, a narrowing zone 307 and / or an expansion zone 308. In this embodiment, the movable portion can extend before and / or after the pressure zone applied by the bar.

[0076] In another embodiment, bars have a specific design and geometry to specifically shape the narrowing zone, the expansion zone and / or the resistance zone.

[0077] Maintaining a small and regular deformation of the cross-sectional area C over a long movable portion after extrusion is crucial to have a food product with the same or similar properties as those obtained if the extrusion occurs without the valve. After extrusion, extruded material exhibits high viscosity, and any abrupt geometric constraints will lead to creation of secondary flow patterns such as vortices and eddies. Non-negligible secondary flow alters the flow profile and the physical properties of the food product. In the valve described herein, the combination of a non-abrupt narrowing zone, a non-abrupt expansion zone allows to minimize the abrupt geometric constraints. In other words, the small variation of the opening in the valve along the passage of the extruded material in the valve allows the extruded material do not exhibit substantial macroscopic deformation of the flow profile after the valve.

[0078] In one embodiment the valve comprises an aperture sensor that measures the aperture of the valve. The sensor can be of any kind and for example measure the aperture via the position of the bar, or bars, compared to it, or to their, initial position, or by optical means, magnetic means, mechanical means etc.

[0079] In one embodiment, the extrusion system, comprising the extruder and the valve, further comprises a plurality of product sensors, said product sensors can be flow rate sensors, pressure sensors, temperature sensors and any other relevant sensors. Product sensors can be located after the extruder, at the valve after the constriction portion, before the constriction portion and / or along the constriction portion. Products sensors can measure any parameters related to the food process fabrication such as any extrusion parameter but not limiting to temperature of the endplate, ratio of ingredients, cooling power of the cooling dies, pressure, speed of the screws, quantity of material extruded per time unit. Alternatively, products sensors can measure a physical characteristic of the extruded material such as moisture content, fibrosity, stiffness, color, etc.

[0080] In one embodiment a control feedback loop is used to control the valve. The control feedback loop is configured to receive data from the aperture sensor and the product sensor. If the value from the product sensor is different from a target value defined by an operator or by a software, then the control feedback loop can adjust the extruded material flow rate by changing the aperture of the valve to reach the target value. The control feedback loop is configured to control the aperture of the valve in response to at least one product sensor.

[0081] Extrusion systems can have a natural oscillation frequency observable as pressure variation or oscillation. With product sensors such as pressure sensors, the control feedback loop and the valve, it is possible to measure the pressure and by actuating the valve to dampen these pressure oscillations.

[0082] In one embodiment the valve comprises a cleaning arrangement located after the movable portion, configured to empty at least part of the valve from extruded material, from the cleaning arrangement to the end of the valve. Alternatively, the cleaning arrangement is configured to empty the extruded material from the cleaning arrangement to the end of the downstream of the extrusion system. The downstream extrusion system can comprise a die, a cooling die, splitter, in line sensors, and any other devices or apparatus used to produce food. When the valve is in closed position and the flow rate is null, the cleaning arrangement can be used and can expel the extruded material. The cleaning arrangement can push the extruded material out with a fluid such as air, nitrogen, carbon dioxide, steam, pressurized water, foaming fluid or a combination thereof. Alternatively, the cleaning arrangement can push the extruded material out with a solid piece having the shape of the inner shape of the outlet end. The solid piece can be made of metal, ceramic, plastic or any other material suitable. The solid piece can be pushed by employing a diverse range of methods such as but not limiting to the utilization of actuators, pneumatic systems, magnetic forces, hydraulic mechanisms, servo motors.

[0083] The temperature of the valve can be controlled by heating or cooling the constriction portion, alternatively the constriction portion can be thermically insulated by an insulating material or by a multiple jacketed structure.

[0084] It is understood that other pipes and / or devices such as sensors, flow regulation devices, structuring devices and / or injection devices can be placed before and / or after the valve.

[0085] It is possible to compare several valves together by calculating the ratio of the elongational rate divided by the length of the movable portion e / L of the extruded material at a given volume flow rate through the valve can be calculated and the variation of the cross-sectional area C in function of the flow direction of the extrudate material x. Those two characteristics values are calculated for 6 valves. Two comparative valves, usually used to modify the flow rate of viscoelastic material such as extruded plant-based products, are compared to 4 valves of the present invention with different movable portion shapes.

[0086] All the extruded materials are composed of 35 wt% of soy proteins, 1 wt% of vegetable oil and 64 wt% of water. The extrusion temperature at the end plate of the extruder is 139°C, the end plate pressure is 12 bar. The pressure after the valve is reduced to 6 bar in the cooling die which is cooled at 60°C. The first comparative valve is the valve described in WO2022135732A1 and presents a constriction portion length equal to 0.7 cm and a maximum opening of 1 cm. When the valve is half closed the volumetric flowrate is 7.576.10sm3.s-1, the maximum value of e / L is 1973 m-1.s-1and the maximum variation of the cross section |dC / dx|is equal to 0.0882 m.

[0087] The second comparative valve is an industrial valve from Volt select named Hygienic Diaphragm Valve DV4515 and presents a constriction portion length equal to 9.8 cm and a maximum opening of 5 cm. When the valve is half closed the volumetric flowrate is 1.01.10'4m3.s-1, the maximum value of s / L is 152 m-1.s-1and the maximum variation of the cross section \dC / dx\\s equal to 0.0395 m.

[0088] The first valve according to one embodiment has a narrowing zone and an expansion zone with a shape of tangent hyperbola, and presents a constriction portion length equal to 10 cm and a maximum opening of 1.3 cm. When the valve is half closed the volumetric flowrate is 5.051.10'7m3.s-1, the maximum value of s / L is 3 m-1.s-1and the maximum variation of the cross section \dC / dx\\s equal to 0.0045 m.

[0089] The second valve according to one embodiment has a narrowing zone and an expansion zone with a shape of a hyperbola, and presents a constriction portion length equal to 100 cm and a maximum opening of 6 cm. When the valve is half closed the volumetric flowrate is 1.073.10'4m3.s-1, the maximum value of s / L is 0.1 m-1.s-1and the maximum variation of the cross section \dC / dx\\s equal to 0.0068 m.

[0090] The third valve according to one embodiment has a narrowing zone and an expansion zone with a shape of a hyperbola, and presents a constriction portion length equal to 10 cm and a maximum opening of 1.3 cm. When the valve is half closed the volumetric flowrate is 5.051.10'7m3.s-1, the maximum value of s / L is 1.4 m-1.s-1and the maximum variation of the cross section|dC / dx| is equal to 0.0001 m.

[0091] The fourth valve according to one embodiment has a narrowing zone and an expansion zone with a shape of hyperbola, and presents a constriction portion length equal to 50 cm and a maximum opening of 6 cm. When the valve is 84% half closed the volumetric flowrate is 7.576.10'5m3.s-1, the maximum value of s / L is 0.4 m-1.s-1and the maximum variation of the cross section|dC / dx| is equal to 0.029 m.

[0092] The fifth valve according to one embodiment has a narrowing zone and an expansion zone with a linear shape, and presents a constriction portion length equal to 17 cm and a maximum opening of 6 cm. When the valve is 27% half closed the volumetric flowrate is 1.14.10'4m3.s-1, the maximum value of s / L is 86.1 m-1.s-1and the maximum variation of the cross section|dC / dx| is equal to 0.024 m.

[0093] Fig. 6a presents extruded materials after extrusion passing through the third valve presented previously partially closed and then texturization through a cooling die.

[0094] Fig. 6b presents extruded materials after being extruded, passing through a comparative valve described in WO2022135732A1 and then texturization through a cooling die.

[0095] Fig. 6c presents extruded materials after extrusion and texturization through a cooling die, without valve.

[0096] On Fig. 6a and Fig. 6c, we can observe two undisturbed extruded materials with a flow profile having substantially the same characteristic parabolic shape and a smooth regular surface. Fig. 6b presents an extruded material with a non-parabolic flow profile. This appears because of secondary flows present after the valve with a large variation of the cross-sectional area over a short deformation length, creating secondary flows and vortexes. Therefore, the shape of the flow profile of the extrudate material is drastically changed, resulting in different physical properties of this food product.

[0097] In another embodiment the valve comprises two movable portions or more positioned at, at least two distinct positions along the constriction portion.

[0098] In another embodiment the valve can have a plurality of bars, which can work together to create a larger movable portion or a movable portion with a specific shape. Alternatively, the plurality of bars can work individually to create a plurality of movable portions along the constriction portion.

[0099] In another embodiment the inner cross section of the inlet end opening, and the outlet end opening have different sizes. One or several bars can be used to both change the flow rate of the extruded material but also to have a reduction or an enlargement of the outlet end compared to the inlet end. The valve can be used after the extruder and without any other device after the valve. In other words, after the valve, the extruded material is flowing into air and possibly used as a food product. In one embodiment, the cross section area of the inlet end opening of the valve is larger than the cross section area of the outlet end opening of the valve, this allow to control the flow rate but also to increase the shear of the extrudate and therefore elongate the flow profile of the extrudate without creating any secondary flow. Alternatively, the cross section area of inlet end opening of the valve is smaller than the cross section area of the outlet end opening of the valve, this allow to control the flow rate but also to decrease the shear of the extrudate and therefore reducing the elongation of the flow profile of the extrudate without creating any secondary flow.

[0100] It is understood that several valves can be used in series i.e. one after the other, with or without other devices between them.

[0101] In another embodiment presented Fig. 7, a flow splitter 710 comprising an entry and a plurality of exits, is connected at the end of the extruder die to split the flow of extruded material into a plurality of streams. At each flow splitter 710 exits are connected the inlet end of one valve 700 and the outlet end of each of said valve 700 is connected to a different cooling die 720. This configuration allow to have one extruder feeding a plurality of cooling dies. A plurality of products sensors can be added along the system comprising the extruder, the splitter, at least 2 valves with each having an aperture sensor and at least 2 cooling dies, each cooling dies connected to a different valve. Pressure sensors can be added before and / or after the constriction portion. Flow rate sensors can be added before and / or after the cooling dies. The control feedback loop is configured to receive data from the aperture sensors and the product sensors. If the value from the product sensors is different from a target value defined by an operator or by a software, then the control feedback loop can adjust the extruded material flow rate by changing the aperture of the valve, or valves, to reach the target value. The control feedback loop is configured to control the aperture of the valve in response to at least one product sensor. The target value can be defined by an operator, a software and can be an extrusion parameter or a physical characteristic of the extruded material. The control feedback loop can also control other parameters related to the food process fabrication such as any extrusion parameter but not limiting to temperature of the endplate, ratio of ingredients, cooling power of the cooling dies, pressure, speed of the screws, quantity of material extruded per time unit.

[0102] For usual plant-based food product high moisture extrusion systems, the cooling capacity of the cooling die is limiting the total amount of extruded material, therefore having multiples cooling dies after the extruder allows to increase the production rate of the food product. This embodiment has the advantage of having a plurality of cooling dies therefore augmenting the production rate compared to the precedent embodiment but also to adapt the production rate of the food product. Valves also allow to finely tune the flow rate into each cooling die, therefore having substantially the same food product produced by all streams at the same time. In other words, the differences in terms of food product flow rates between each stream can be less than 10% and preferably less than 5%. Alternatively, each valve is configured to have a specific flow rate, which may be identical or different from the others; therefore, the food products produced at each stream have similar or different properties. In other words, if the different streams have the same cooling die, different food products can be produced at the same time if different flow rates are applied to each valve. Alternatively, if the cooling dies are different, the flow rate of each valve can be adapted to compensate for the differences of the cooling dies and thus obtain the same food product.

[0103] In one embodiment fine tuning of the opening of the valve and of the cooling power of the cooling die make it possible to produce the same food product with substantially the same physical properties by changing the quantity per time unit of extruded material flowing in the cooling die and / or by changing the cooling power of the cooling die. In one embodiment this is obtained by having substantially the same temperature of the extruded material at the end of the cooling die regardless of the size of the opening of the valve. The temperature difference between extruded materials exiting different dies should be lower than 10°C and preferably lower than 5°C and more preferably lower than 3°C.

[0104] This embodiment makes it possible to use the valve to stop the production for specific streams and have other streams continuing to produce. The nonproducing streams can be cleaned with the cleaning device of the valve. It is also possible to remove and / or change the cooling die if needed. The valve can then open and resume production into said streams.

[0105] One embodiment, the valve is added to an existing device. For example, in a cylindrical cooling die 800, as depicted in Fig. 8. It is possible to incorporate the valve at the same place as the cone positioned at the entrance of a cooling die. This cone evenly divides the extrudate flow into a cylindrical shape, enhancing the cooling process and physical structure of the extruded material. In this setup, the valve is at the entrance of the cooling die, within the cone. In this embodiment the cone should be made of a flexible material capable of being deformed by the pressure applied to it by the valve. The valve can comprise a first movable portion shaped like a ring concentric with the extruder pipe and adjacent to the cone's inner surface. This can be done for example by applying a bar 830 having the shape of a ring on the movable portion and actuating the bar to move the movable portion. One bar is enough but a second bar 840 with the shape of a ring or a cylinder can be positioned concentric with the extruder pipe and adjacent to the outer surface of the cone. During the constriction, the bar or the two bars can move toward the center of the center axis of the flow channel and / or toward each other and then decrease the aperture of the cone, reducing the flow rate without creating disturbances such as secondary flow or vortexes in the extrudate flow profile.

[0106] The valve described herein can also be used for other purposes than producing food products.

Claims

Claims:

1. An extrusion system comprising an extruder and a valve, configured to extrude a viscoelastic extruded material from the extruder, with the extruded material flowing through the valve at a volumetric flow rate V, said valve having a constriction portion, wherein the constriction portion comprises at least a first movable portion, with a cross-sectional area C orthogonal to the extruded material flow direction x and a length L along the extruded material flow direction x, moving towards and away from a center axis of the flow channel to vary the opening width, characterized in that the cross-sectional area C varies along the direction x such that \dC / dx\ is inferior to 0.03 m and preferably below 0.01 m throughout the entire length of the valve; and the elongation rate to length ratio e / L is inferior to 100 m-1.s-1, preferably inferior to 50 m-1.s-1and preferably inferior to 15 m-1.s-1throughout the entire length of the valve.

2. The extrusion system comprising an extruder and a valve according to claim 1, wherein the constriction portion comprises a second movable portion, the second movable portion facing the first movable portion, and the second movable portion moves towards and away from a center axis of the flow channel to vary the opening width.

3. The extrusion system comprising an extruder and a valve according to claim 1 or 2, wherein the aperture of the valve is modulated by moving the first movable portion and / or the second movable portion, the valve can be open, close or partially close.

4. The extrusion system comprising an extruder and a valve according to any of the preceding claims, wherein the constriction portion of the valve is made in an elastically deformable material that can be pinched by a first and / or a second bar and the extruded material flow in said elastically deformable material deformed to form the first movable portion and / or the second movable portion, preferably the pinching is done by moving the two bars in opposite direction.

5. The extrusion system comprising an extruder and a valve according to claim 4, wherein the first bar and / or the second bars are convex, forming a first convex movable portion and / or a second convex movable portion.

6. The extrusion system comprising an extruder and a valve according to claim 4 or 5, wherein the elastically deformable material is made of rubber.

7. The extrusion system comprising an extruder and a valve according to claims 4 to 6, wherein more than one bar are used to create the first movable portion and / or second movable portion.

8. The extrusion system comprising an extruder and a valve according to any of the preceding claims, wherein the valve comprises at least one aperture sensor for measuring the aperture of the valve, the aperture sensor and the extrusion system comprise at least one product sensor configured to measure physical characteristic of the extruded material and / or extrusion parameter, the extrusion system adjusting extrusion parameters according to the data received from the at least one aperture sensor and the at least one product sensor.

9. The extrusion system comprising an extruder and a valve according to claim 8, further comprises a control feedback loop configured to control the aperture of the valve in response to at least one product sensor.

10. The extrusion system comprising an extruder and a valve according to any of the preceding claims, comprising a plurality of valves and further comprising a flow splitter, the flow splitter comprising an entry and a plurality of exits, the entry being configured to receive the extrudatefrom the extruder to split a flow of extruded material into a plurality of streams, the plurality of valves being connected downstream of the exits and optionally a plurality of dies configured to structure the food product, being connected downstream of the valves.

11. The extrusion system comprising an extruder and a valve according to any of the preceding claims, wherein the valve comprises a cleaning arrangement located downstream of the movable portion, configured to empty part of the valve and expel the extruded material downstream of the valve.

12. A method to produce a food product comprising:-providing an extrusion system comprising an extruder and a valve according to any of claims 1 to 11, wherein the valve is connected to the extruder;-receiving, mixing, and conveying a plurality of ingredients in the extruder to produce an extruded material, the plurality of ingredients including a protein powder and water; and-conveying the extruded material to the valve.

13. The method according to claim 12, wherein the extrusion system comprises at least a product sensor and a control feedback loop to control the aperture of valve in response to the at least one product sensor.

14. The method according to claim 13, wherein a splitter is located downstream of the extrusion die and configured to split the extruded material into a plurality of streams, each stream comprising at least one valve with an aperture sensor, one product sensor; and the control feedback loop controlling each valve independently in response to each product sensor of each stream.

15. The method according to claims 12 to 14, wherein a plurality of dies configured to structure the food product is each connected directly or indirectly downstream of each valve.

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