Method and installation for smoking a food product

Abstract

Method and installation for smoking a food product. A method for preparing a food product, comprising the steps of: Injecting smoke into a tank (32) of a mixer cooled to a temperature that leads to condensation of the smoke, and evacuating the smoke through an exhaust system (7) connected to the tank. Figure for the abbreviated version: Fig. 1

Description

Title of the invention: Method and installation for smoking a food product technical field

[0001] The present invention relates to the preparation of smoked food products, in particular based on meat or fish. Previous technique

[0002] Patent application EPI321041 describes a method for smoking a product This food-grade smoking process relies on the use of a single-jacketed mixer and the injection of a smoking agent, which can be liquid or gaseous, into its rotating vat. The smoking process may be preceded and / or followed by a drying operation.

[0003] When using a liquid smoking agent consisting of smoke condensate, it can be atomized in the tank by maintaining a negative pressure in the tank using a vacuum pump connected to the mixer, for example at a pressure between 20 and 45 mbar. Steam can be injected into the tank at the same time as the smoke condensate.

[0004] When using a gaseous fuming agent, it can be introduced at one axial end of the tank, while the circulation of this fuming agent is ensured within the tank by suction extraction at the opposite end, the pressure in the tank during this phase being between 100 and 500 mbar. A subsequent drying operation is recommended to improve the fixation of the fumes on the treated products.

[0005] Application EP3695726A1 describes a smoking installation comprising a rotating tank into which smoke is injected through an inlet located substantially on the axis of the tank. Smoke extraction is carried out via a duct connected to an extractor. A valve is located downstream of the extractor to regulate the flow rate of smoke extraction to the outside; some of the smoke can be recycled back to the smoke generator. Steam injection can take place in a smoke supply duct upstream of the tank. After the smoke has been evacuated, a vacuum can be created in the tank. Description of the invention

[0006] There is a need to further improve smoking processes and installations in order to benefit from a process that is simple to implement and leads to excellent results in terms of appearance and taste quality of the products.

[0007] The invention aims to meet this need. Summary of the invention

[0008] The invention thus relates to a process for preparing a food product, comprising the steps of: a. Injecting smoke into the food product, in a mixer tank cooled to a temperature that leads to condensation of the smoke, b. Preferably, inject water into the tank, c. Evacuate the smoke through an evacuation circuit connected to the tank.

[0009] Step c) can take place continuously during step a) or intermittently. The same applies to step b).

[0010] Preferably, the mixer tank has a double jacket, and the cooling of this tank is achieved by circulating a refrigerant liquid in the double jacket.

[0011] The invention makes it possible to obtain good fixation of the smoke on the product, thanks to the cooling of the tank, and the injection of water is advantageous because it promotes the condensation of the smoke.

[0012] This results in smoked products that are particularly attractive to the consumer.

[0013] The term "smoke" refers to any smoking agent obtained from plant-based products, in the form of logs, chips, or sawdust, preferably from walnut, beech, oak, apple, fir, cherry, maple, or a mixture thereof. The smoke may be generated by friction. It is also possible to use smoke generated from liquids or smoke flavorings.

[0014] The products placed in the tank can be free to move within it, under the effect of the rotation of the tank.

[0015] Preferably, the smoke is injected using a smoke delivery system comprising an accelerator located upstream of the tank. This accelerator may be located downstream of a smoke generator. It may include a rotating turbine or propeller.

[0016] The overpressure generated at the accelerator outlet is, for example, between 85 and 400 Pa. The gas flow rate at the accelerator outlet is, for example, between 140 and 275 m³ / h.

[0017] Preferably, the admission of the smoke and its evacuation take place on the same side of the tank, preferably its front side, through which the loading and / or unloading of the food product to be treated can also be carried out.

[0018] The water is preferably injected into the tank by atomization, that is, in the form of a mist of fine water droplets. The water injection can be carried out substantially along the longitudinal axis of the tank. The water can be injected intermittently when the mixer is small and continuously when it is large. Large size. The temperature of the injected water can be controlled by means of a heat exchanger, either hot or cold. The process may involve steam injection into the tank, particularly simultaneously with water injection by atomization.

[0019] Preferably, the amount of water injected remains relatively small so as not to saturate the product and to preserve its attractive appearance. For example, the amount of water injected ranges from 0.2% to 1.5% relative to the mass of the product introduced into the tank. The water is sprayed, for example, at a rate ranging from 0.51 / h to 21 / h in the case of continuous spraying.

[0020] The circulation of fumes in the exhaust system is advantageously achieved without suction, except at the end of the cycle to facilitate the evacuation of fumes from the mixer tank. This avoids the drawbacks of fume recirculation, namely the concentration of certain compounds that could lead to explosive conditions.

[0021] However, when smoking conditions permit, at least partial recirculation of the smoke between the tank and the smoke generator can be provided for, with detection of an accumulation of one or more predefined gaseous compounds likely to lead to explosive operating conditions, as detailed later.

[0022] The smoke exhaust system may vent directly into the atmosphere but preferably includes a damper to control the smoke density in the tank during smoking. This damper is, for example, a passive damper or a damper electrically controlled by a system controller. The damper can be controlled based on the return from a concentration probe of a predefined compound or from an explosimeter, particularly in the event of at least partial smoke recirculation.

[0023] The process may include, as mentioned above, at least partial recirculation of the fumes between the fume generator and the tank. In this case, preferably, the process includes monitoring of the recirculated gases using at least one explosimeter-type sensor. The concentration of certain critical compounds in the recirculated gases, such as the concentration of CO, H2, CH4, and / or VOCs (organovolatile compounds), can be monitored.

[0024] In one example of implementation of the process, the food product is subjected, before smoking, to a preliminary evaporative drying operation in the tank.

[0025] In the presence of a double jacket, this evaporative drying can be done with circulation of a hot fluid in the double jacket.

[0026] Drying the surface prepares it and facilitates the deposition and absorption of smoke, and makes it possible to obtain smoked products that are particularly attractive visually and in terms of taste and consistency.

[0027] Preferably, the cooling of the mixer during the smoking operation is chosen so as to maintain the food product during the smoking operation at a temperature between -10° and +12°C, better between -2°C and +10°C.

[0028] In the presence of a double jacket, the temperature of the fluid circulating in the jacket is set to a temperature adapted to the desired cooling.

[0029] The process can be implemented with the same tank closure cover, through which the injection of smoke, steam, evacuation of smoke, injection of water, and creation of vacuum are carried out.

[0030] In one embodiment, the process is implemented with two different lids, one being used during the creation of the vacuum in the tank and the injection of steam, the other during smoking, with injection of smoke and water and evacuation of the smoke. At least one of these lids, in particular the one used for smoking, can be hinged on a support structure, if necessary, to facilitate its installation and removal.

[0031] The invention also relates, according to another aspect, to a food processing installation, in particular for implementing the smoking process as defined above, this installation comprising: - A double-jacketed mixer tank, or a temperature-controlled enclosure in which the tank is placed, - a cold fluid supply circuit for the double jacket during a smoking operation, or an air conditioning system for the enclosure that generates a sufficient temperature difference with the tank to obtain the desired temperature for the tank, - a smoke generator, - a smoke supply circuit for the tank, preferably including an accelerator upstream of the tank, and preferably downstream of the smoke generator, - a smoke evacuation system, - preferably, a water atomization device in the tank.

[0032] The smoke extraction system can be arranged so that smoke is evacuated by natural circulation, without suction. This allows the smoke to be concentrated in the tank. The installation may include a smoke recirculation system, if necessary, with one or more sensors to prevent the occurrence of dangerous operating conditions.

[0033] The smoke extraction circuit may include a smoke density control valve inside the tank. This allows the smoke extraction to be restricted in order to obtain the desired smoke accumulation in the tank.

[0034] The smoke supply circuit for the tank and the smoke evacuation circuit can open into the tank on the same side of it.

[0035] The installation may include a steam supply to the tank.

[0036] The installation may include a conduit connected to a vacuum source, allowing the tank to be subjected to evaporative drying or vacuum mixing.

[0037] The installation can be arranged to circulate a hot fluid in the aforementioned double jacket when needed, for example to ensure defrosting or during an evaporative drying operation.

[0038] The installation may include a single cover to which are connected the smoke supply circuit for the tank, the smoke evacuation circuit, the steam supply, the conduit connected to the vacuum source, and a water and air inlet to the water atomization device.

[0039] Alternatively, the installation includes two covers, one being used for evaporative drying and the other for smoking.

[0040] The cover used during evaporative drying is connected to the vacuum source and the steam supply.

[0041] The lid used during smoking is connected to the smoke supply circuit, the smoke evacuation circuit, and the water and air intake.

[0042] At least one of these two lids, in particular the one used for smoking, may be hinged on a support structure. In this case, the smoke evacuation circuit may include a pivoting fitting that rotates with the lid. Brief description of the drawings

[0043] The invention will be better understood upon reading the detailed description that follows, a non-limiting example of its implementation, and upon examination of the accompanying drawing, in which:

[0044] [Fig. 1] [Fig. 1] schematically represents, in perspective, with transparency to show certain details, a first example of a smoking installation according to the invention, with a single lid,

[0045] [Fig.2] [Fig.2] schematically represents, in perspective, with transparency to show certain details, a second example of a smoking installation according to the invention, with a double lid, when using the lid for evaporative drying,

[0046] [Fig.3] [Fig.3] represents the installation of [Fig.2] when using the lid for smoking,

[0047] [Fig.4] [Fig.4] illustrates a variant with a hinged lid of the installation shown in Figures 2 and 3,

[0048] [Fig. 5] illustrates steps of an example of a process according to the invention, and

[0049] [Fig.6] is a view analogous to [Fig.5] of a variant of the process. Description of the implementation methods

[0050] Figure 1 shows an example of a smoking installation 90 according to the invention, comprising a mixer 2 having a double-walled tank 32, the front of which has a frustoconical wall closed in its center by a front cover 22 allowing the introduction and removal of food products. The tank can be emptied via the front cover 22. When the tank has an internal paddle, the tank can be rotated in the opposite direction to the direction of travel during emptying. The efficiency of emptying can be improved by installing the rear legs on lifting jacks, if necessary.

[0051] The tank may include, as illustrated, an inspection hatch 31, which may allow cleaning of the inside of the tank, or even, in some cases, be used for loading the tank. This loading may also be carried out using another inspection hatch (not shown) by means of a conveyor.

[0052] The double jacket 3 may include a coil or a corrugated sheet providing a helical conduit, in which a heat transfer fluid circulates.

[0053] The tank 32 is rotatable and can rotate in a cradle 33 around its longitudinal axis thanks to a set of rollers (not apparent) carried by the cradle 33.

[0054] The installation 90 comprises a smoke generator 1, known per se, equipped in the upper part with an accelerator 4 connected to a primary pipe 11 which connects via a smoke circuit isolation valve 10 to a secondary pipe 12, itself connected to an injection / extraction system 35. The latter is supported by the front cover 22 by means of a rotating fitting 36, centered on the longitudinal axis of the tank.

[0055] The double jacket 3 is supplied from the rear of the tank with a heat transfer fluid whose temperature is chosen according to the operation to be carried out in the tank, smoking or evaporative drying, or simply to control the temperature of the product. This fluid is preferably glycol water.

[0056] A cold water and air intake pipe 19 connects to the injection system 35, which includes a water or air / water nozzle for atomizing the water, which can be sprayed according to a cone 14 with an axis substantially parallel to the longitudinal axis of the tank, as illustrated.

[0057] The installation may also include a steam supply pipe 20, connecting to the injection / extraction system 35, the latter being, for example arranged to deliver steam along a cone 13 with an axis substantially parallel to the longitudinal axis of the tank.

[0058] The diffusion of the smoke in the tank can take place along a cone 15 with an axis substantially parallel to the longitudinal axis of the tank.

[0059] The installation includes a smoke evacuation circuit 7, connected to the injection / extraction system 35 by a pipe 17.

[0060] The evacuation circuit 7 may include a valve 8 for isolating the smoking circuit, allowing, depending on its degree of opening, the regulation of the smoke density inside the tank.

[0061] The installation 90 may include a high-vacuum inlet circuit 6, connected to the injection / extraction system 35 via an isolation valve 16. A venting connection 21, connected to a primary vacuum line 18, allows the pressure in the tank to be controlled, if necessary via a solenoid valve (not shown).

[0062] The operation of the installation 90 can be controlled by a programmable logic controller (PLC).

[0063] We will now describe, with reference to [Fig.5], different stages of an example of a smoking process according to the invention.

[0064] The food product to be smoked is introduced in step 100 into the mixer tank through the front cover 22 or otherwise. It may be a smoked product or other.

[0065] The tank may have been previously cooled by circulating the cooling fluid in the double jacket at a temperature between 0 and 2°C, in particular if smoking takes place after brining and / or drying in a mixer. The setpoint temperature of the cooling fluid is for example -5°C.

[0066] Next, with the cover 22 in place, the tank can be rotated while smoke is injected in step 101.

[0067] During this injection, gas circulation can take place in the tank, the smoke being pushed into the tank by the accelerator 4 while the smoke-laden air escapes through the exhaust circuit 7, depending on the degree of opening of the valve 8.

[0068] Water can be atomized intermittently in the tank at step 103, during the smoking operation.

[0069] Steam can also be injected at step 105, at the same time as water is atomized.

[0070] The low temperature of the food product contained in the tank, as well as the presence of atomized water, promotes the condensation of the smoke on the food product.

[0071] Once the smoking operation has been carried out, the food product can be extracted from the tank through the front cover 22 or otherwise, in step 106.

[0072] It may be advantageous, particularly for all products of animal origin, to have a drier surface and therefore better adhesion of the smoke to the product, to subject the food product, before the smoking stage, to an evaporative drying operation.

[0073] In this case, the process may include, as illustrated in [Fig. 6], between the food product introduction and smoke injection steps, an evaporative drying step 110 during which a vacuum is generated in the tank while the double jacket 3 receives a hot fluid. In an alternative embodiment, the tank does not have a double jacket, although this is preferred as a means of compensating for the endothermic nature of the evaporative drying reaction.

[0074] Evaporative drying includes, for example, the creation of a vacuum in the tank via the pipe 6 such that the absolute pressure in it is between 0.1 and 20 mbar, better 0.1 and 15 mbar, the double jacket 3 of the tank being brought to a temperature between 5 and 60 °C, better 5 and 50 °C, by circulating in it a fluid at a suitable temperature.

[0075] In the variant of the installation 90 illustrated in figures 2 and 3, two different covers are used respectively for evaporative drying and smoking.

[0076] In [Fig.2], the installation 90 is shown with a lid 24, in place, used during evaporative drying, and a lid 25, in standby, used during smoking.

[0077] The cover 25 is shown in place on [Fig.3], the cover 24 being then in standby.

[0078] The cover 24 is connected to the high vacuum inlet pipe 6, the primary vacuum pipe 18 and the steam inlet pipe 20, and has its own swivel fitting.

[0079] The cover 25 is connected to the secondary smoke inlet pipe 12, to the smoke outlet pipe 17 and to the water and air inlet pipe 19.

[0080] Assuming that evaporative drying and smoking are carried out successively, the lid 24 is first fixed to the tank, for example using three fasteners. The lid is connected to the vacuum system via the pipe 6.

[0081] After mixing, the inside of the tank is brought back to atmospheric pressure using the primary vacuum line 18, then the cover 24 is detached, for example by removing the three fasteners, and the cover 24 is slid on a guide bar and wedged at the end of the stroke.

[0082] The smoking lid 25 is then put in place of the lid 24. It is attached in the same way with the three fasteners. If the pipes 12 and 17 are not connected, they are connected, and then the smoking process is started.

[0083] One of the covers 24 and 25, for example the cover 25 used for smoking, can be mounted in an articulated manner on a support structure 91, using a swivel fitting 92 connected to the evacuation circuit 7, as illustrated in [Fig.4].

[0084] Of course, the invention is not limited to the examples just described.

[0085] For example, it is possible to make the mixer differently, for example with mixing blades and a fixed tank.

[0086] It is particularly advantageous for the tank to be double-walled. However, in one embodiment, the tank is cooled by installing it in a temperature-controlled chamber at a temperature chosen to bring the tank to the desired temperature, for example, a cold room with an ambient temperature at least 5°C below the desired cooling temperature for the tank at the beginning of the cooling cycle. The same can be done for heating the tank, if the chamber's temperature control allows it to be heated.

Claims

Demands

1. A process for preparing a food product, comprising the steps of: a. Injecting smoke into contact with the food product, into a tank (32) of a mixer cooled to a temperature leading to condensation of the smoke, b. Evacuating the smoke through an evacuation circuit (7) connected to the tank.

2. Method according to claim 1, the tank being double-jacketed (3) and the cooling of the tank being effected by circulation of a refrigerant liquid in the double jacket (3).

3. A method according to one of the two preceding claims, the smoke being injected using a smoke delivery circuit comprising an accelerator (4) placed upstream of the tank (11).

4. A method according to any one of the preceding claims, the admission of smoke and its evacuation taking place on the same side of the tank.

5. A method according to any one of the preceding claims, comprising injecting water into the tank.

6. Method according to claim 5, the water being injected at a predefined temperature.

7. A method according to any one of claims 5 and 6, the water being injected into the tank by atomization.

8. A method according to any one of claims 5 to 7, the quantity of water injected being between 0.2 and 1.5% of the mass of the product introduced into the tank.

9. A method according to any one of the preceding claims, the smoke evacuation circuit comprising a shutter (8) allowing control of the smoke density in the tank during smoking.

10. A method according to any one of the preceding claims, the circulation of smoke in the evacuation circuit taking place without suction.

11. A method according to any one of the preceding claims, comprising at least partial recirculation of the fumes between the tank and a fume generator, with detection of an accumulation

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19. of one or more predefined gaseous compounds capable of leading to explosive operating conditions. A method according to any one of the preceding claims, wherein the food product is subjected, before smoking, to a preliminary evaporative drying operation in the tank. A method according to claim 12, the tank comprising a double jacket (3), the evaporative drying being carried out with the circulation of a hot fluid within the double jacket. A method according to any one of the preceding claims, with reference to claim 2, the temperature of the fluid circulating in the envelope (3) during the smoking operation being chosen so as to maintain the food product during the smoking operation at a temperature between -10°C and +12°C, preferably between -2°C and 10°C. A method according to any one of the preceding claims, comprising a steam injection, in particular simultaneously with a water injection into the tank by atomization. Food processing plant, comprising: - A double-jacketed mixer tank (32) (3), or a temperature-controlled enclosure in which the tank is placed, - a cold fluid supply circuit for the double jacket (3) during a smoking operation, or an air conditioning system for the enclosure capable of generating a sufficient temperature difference with the tank to obtain the desired temperature for the tank, - a smoke generator (1), - a supply circuit (11, 10, 12) for the smoke tank, - a smoke evacuation circuit (7). Installation according to claim 16, the tank (32) comprising a double jacket (3). Installation according to one of claims 16 and 17, comprising a water atomization device in the tank. Installation according to any one of claims 16 to 18, the smoke extraction circuit being arranged so that the smoke is evacuated by natural circulation, without suction.

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26. Installation according to any one of claims 16 to 19, the smoke extraction circuit comprising a smoke density adjustment shutter (8) inside the tank. Installation according to any one of claims 16 to 20, the smoke supply circuit to the tank and the smoke evacuation circuit opening into the tank on the same side of it. Installation according to any one of claims 16 to 21, comprising a steam supply (20) to the tank. An installation according to any one of claims 16 to 22, comprising a conduit (6) connected to a vacuum source, allowing the tank to be subjected to evaporative drying. Installation according to claims 17 and 23, being arranged to circulate a hot fluid in the double jacket during an evaporative drying operation. Installation according to any one of claims 16 to 24, comprising an accelerator (4) upstream of the tank, and preferably downstream of the smoke generator (1). An installation according to any one of the preceding claims, comprising two covers (24; 25), one (24) being used for evaporative drying and the other (25) for smoking.

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