Cold pressing method and plant for the production of an animal food and related animal food

Abstract

The invention relates to a method for producing an animal food (A), in particular for small pets, e.g., cats and dogs. The method comprises a step of preparing a mixture comprising an amount (Q1) of dehydrated and powdered raw materials so that said mixture of said raw materials has a relative humidity lower than 14%, a step of adding to said mixture of said raw materials an amount (G1) of fat, said amount (G1) of fat being present in a percentage of between 10 and 30% relative to said amount (Q1) of raw materials, a step of compacting said mixture and said fat by means of a cold pressing process, while maintaining the temperature at room temperature values, and a step of cutting the product obtained from said cold pressing process to size.

Description

[0001] DESCRIPTION

[0002] TITLE: COLD PRESSING METHOD AND PLANT FOR THE PRODUCTION OF AN ANIMAL FOOD AND RELATED ANIMAL FOOD

[0003] FIELD OF APPLICATION OF THE INVENTION

[0004] The present finding falls in the field of animal food production systems, in particular pets such as cats and dogs which have unique and different nutritional needs relative to other small animals such as herbivores.

[0005] In particular, the present finding relates to an animal food production method, a plant for producing said food and to the food obtained by said method and / or plant.

[0006] BACKGROUND ART

[0007] In the field of animal feed, especially for pets such as cats and dogs, the production of food consisting of compacted agglomerates of raw materials, commonly known by the term extruded kibble, is known.

[0008] According to a known art, said animal food products, henceforth referred to simply as extruded kibble, are obtained by an extrusion process involving the use of very high temperatures a large number of times during the entire production process. The main steps for producing kibble according to the known art comprise:

[0009] - drying raw materials;

[0010] - refining / grinding and mixing raw materials;

[0011] - addition of thickeners / agglomerants / amides which are nutritionally useless but indispensable for the creation of the extruded kibble;

[0012] - adding additives (e.g., preservatives, antioxidants or chemical additives); - conditioning by humidification of the raw material mixture;

[0013] - heating the paste thus formed at temperatures of for example 280°C (and above) and pushing it through extruders of any shape and size;

[0014] - adding nutritional chemical additives, such as vitamins, minerals, etc.);

[0015] - drying the kibble to make it crunchy, passing it through a dryer at temperatures up to 200°C;

[0016] - spraying fat.

[0017] In this last step, the kibble is sprinkled with fat, which acts as a natural appetiser to increase the flavour and make the kibble palatable.

[0018] The production process of kibble by extrusion mentioned above has some drawbacks.

[0019] A first drawback of said process is related to the high temperatures, e.g., 280°C during extrusion and / or 200°C in the final drying step, which have the negative effect of inactivating many of the nutrients contained in the raw materials used, such as vitamins and / or proteins. In particular, the duration of the extrusion at high temperatures is around 20 seconds.

[0020] The temperature and timing of the known extrusion are intended to make the product pass from 80% to 20% moisture.

[0021] A further moisture reduction of up to about 5% is achieved in the final drying step.

[0022] Another drawback of said process is that it generates kibble completely encased in fat which is exposed to the external environment and is therefore subject to oxidation and / or going rancid. This causes the kibble to deteriorate in the short term. To reduce or avoid such a negative effect, additives such as preservatives and chemical antioxidants are normally used during the production process. Not least, this leads to a disruption of digestion, the primary and main stage of which is chewing. In fact, the 'perfect' and entirely equal shape, also externally fatted, are usually swallowed, thus skipping the first fundamental stage of digestion: chewing.

[0023] Furthermore, kibble obtained by the known processes tends to swell in the animal's stomach and is one of the main causes of dreaded gastric torsion.

[0024] This is due precisely to the type of processing. Indeed, the high temperatures of the extrusion step cause the outside of the kibble to harden and the gases, which are generated by evaporation during extrusion, to form bubbles which remain trapped inside the kibble.

[0025] Another drawback of said process is that it requires the addition of starch, because at high temperatures the kibble would fall apart in the absence of the adhesive action provided by the starch.

[0026] The main aim of the present invention is therefore to solve or at least partially overcome the drawbacks characterising the solutions known in the background art.

[0027] It is a main aim of the present invention to propose a system for the production of kibble by means of cold pressing, which allows to obtain a product which preserves the nutritional properties contained in the starting materials as much as possible.

[0028] It is another aim of the present invention to propose a system for the production of kibble by means of cold pressing which allows to reduce or eliminate the use of preservatives and / or chemical antioxidants.

[0029] It is a further aim of the present invention to propose a system for the production of kibble by means of cold pressing which allows to avoid the deterioration of the product, e.g., oxidation or going rancid in the short term.

[0030] Moreover, thanks to the invention it is possible to optimise resources, e.g., energy, and have a drastically reduced environmental impact.

[0031] It is an aim of the present invention to propose a system for the production of kibble by means of cold pressing which allows for such hardness and palatability without resorting to intrusive cooking, a large number of steps and the use of countless energy and nutritionally irrelevant ingredients, so that it arouses natural interest in the animal and stimulates chewing by using raw materials of animal origin with a relevant fat content.

[0032] EXPOSURE AND ADVANTAGES OF THE INVENTION

[0033] Such and other aims are achieved by virtue of the features of the invention reported in the independent claims 1, 9 and 24. The dependent claims outline preferred and / or particularly advantageous aspects of the invention.

[0034] In particular, in a first aspect thereof, the present invention provides a production method of animal food, in particular for small pets, specifically food for cats and dogs which have specific and different nutritional needs relative to other herbivorous animals. Said method comprises the steps of:

[0035] - preparing a mixture comprising an amount of dehydrated and powdered raw materials so that said mixture of said raw materials has a relative humidity lower than 14%; - adding to said mixture of said raw materials an amount of fat, said amount of fat being present in a percentage of between 10 and 30% relative to said amount of raw materials;

[0036] - compacting said mixture and said fat by means of a cold pressing process while maintaining the temperature at room temperature values;

[0037] - cutting the product obtained from said cold pressing process to size.

[0038] In a preferred embodiment, the mixture of said raw materials has a relative humidity of between 7 and 12%.

[0039] Preferably, the amount of fat is present in a percentage of between 14 and 15% relative to the amount of raw materials.

[0040] According to a preferred embodiment, the raw materials comprise meat and / or fish and / or fruit and / or vegetables and / or herbs.

[0041] In a preferred embodiment, the powdered raw materials have a particle size lower than 1 mm, in particular around 750 microns.

[0042] Preferably, said fat comprises animal fat and / or vegetable fat.

[0043] According to a preferred embodiment, the fat used has a melting point such that at room temperature it is in a fluid, preferably liquid, form.

[0044] In a preferred embodiment, the cold pressing process has a duration lower than 6 seconds.

[0045] In another aspect thereof, the invention concerns a plant for the production of animal food comprising:

[0046] - a mixing unit adapted to receive an amount of dehydrated and powdered raw materials and an amount of fat;

[0047] - a cold pressing unit comprising a die comprising at least one pressing hole extending longitudinally along a main axis, wherein the length of said pressing hole measured along said main axis is between 100 and 200 mm and wherein the outlet surface area of said pressing hole measured in a plane perpendicular to said main axis is between 20 and 40 mm2;

[0048] - a cutting unit arranged downstream of said cold pressing unit for cutting to size the product mechanically pressed by said die.

[0049] In a preferred embodiment, the length of the pressing hole is 150 millimetres.

[0050] Preferably, the outlet area of the pressing hole measured in said plane perpendicular to said main axis is 28 square millimetres.

[0051] According to a preferred embodiment, the pressing hole comprises a first section of a truncated cone shape and a second section of a cylindrical shape on which the outlet of the pressing hole is identified.

[0052] In a preferred embodiment, the cold pressing unit comprises means for pushing the product to be mechanically pressed through said at least one pressing hole.

[0053] Preferably, the die has an annular shape which extends around a central axis and comprises a plurality of pressing holes.

[0054] According to a preferred embodiment, said annular die is rotating.

[0055] In a preferred embodiment, the pressing holes extend radially relative to said central axis in said die and said pushing means of the product to be mechanically pressed are arranged at the central axis of the die.

[0056] Preferably, the pushing means comprise one or more rollers adapted to radially push outwards the product to be mechanically pressed and against the die.

[0057] According to a preferred embodiment, the mixing unit comprises a hopper for feeding the die and is adapted to receive said dehydrated and powdered raw materials and said fat mixed uniformly.

[0058] In a preferred embodiment, the mixing unit comprises conveyor means for conveying said dehydrated and powdered raw materials and said fat to said hopper.

[0059] Preferably, the conveyor means comprise a rotatable worm screw.

[0060] According to a preferred embodiment, the plant further comprises a grinding unit arranged upstream of said mixing unit to reduce raw materials into powder and make them uniform.

[0061] In a preferred embodiment, the plant further comprises a drying unit arranged upstream of said mixing unit to dehydrate said mixture of said fresh raw materials to residual relative humidity values lower than 14%.

[0062] Preferably, the plant further comprises aeration means for conveying air and / or steam to said die.

[0063] In a further aspect, the invention relates to animal food obtained by a cold pressing process, wherein the food comprises:

[0064] - a mixture comprising an amount of raw materials;

[0065] - an amount of fat, wherein said amount of fat is between 10 and 30% relative to said amount of raw materials and said fat is distributed internally in said mixture of said raw materials.

[0066] In a preferred embodiment, said amount of fat is present in a percentage of between 14 and 15% relative to said amount of raw materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Further features and advantages of the invention will be more apparent after reading the following description provided by way of a non-limiting example, with the aid of the figures illustrated in the accompanying tables, wherein:

[0068] - Figure 1 : illustrates a side view of an animal food production plant according to a preferred embodiment of the invention;

[0069] - Figure 2: illustrates in axonometric view a detail of the plant of Figure 1 in a non-operational open configuration for illustration purposes only;

[0070] - Figure 3: illustrates an enlarged detail of Figure 2;

[0071] - Figure 4: illustrates a sectional view of the element of Figure 3;

[0072] - Figure 5: illustrates an enlarged detail of Figure 4;

[0073] - Figure 6: illustrates a food obtained by means of the plant of Figure 1.

[0074] DESCRIPTION OF THE INVENTION

[0075] With reference to Figure 1, the number 1 denotes as a whole a plant in accordance with a first preferred embodiment of the invention.

[0076] The plant 1 allows the production of food A, shown in Figure 6, consisting of a compacted raw material agglomerate.

[0077] In particular, said raw materials are balanced according to the nutritional requirements of pets recognised as carnivores and / or opportunistic carnivores.

[0078] From now on, we will also refer to such food A by the term kibble or raw kibble to differentiate it from the aforementioned known art. The kibble A according to the embodiment illustrated and obtained by means of the plant 1 preferably has the shape of a small cylinder. It is clear that the external shape of the kibble A is not limiting and in embodiment variants can take on different shapes compatible with the production method carried out by a plant according to the invention.

[0079] The plant 1 essentially comprises a mixing unit 10, a cold pressing unit 30 and a cutting unit 80 arranged downstream of said cold pressing unit 30 for cutting the product mechanically pressed by the cold pressing unit 30 to size.

[0080] The plant 1 according to the invention allows, as mentioned, the production of kibble A consisting of an agglomerate of raw materials.

[0081] The raw materials used generally comprise foods such as meat and / or fish and / or fruit and / or vegetables and / or herbs which have been appropriately minced / pulverised.

[0082] By way of example, the following raw materials can preferably be used: dehydrated meat, egg yolk, rice, barley, flax, pumpkin, carrot, red beet, goji berries, banana, cranberries, apricot, apple, pear, rosemary, oregano, rose hip, ginger, turmeric, nettle, willow bark, filipendula, MSM (methylsulphonylmethane), devil's claw, spirulina algae, green-lipped mussel, echinacea angustifolia, bearberry, solidago goldenrod, marshmallow root, valerian, dandelion.

[0083] In a preferred embodiment, the plant 1 is fed with raw materials which have already been suitably dehydrated and minced in powder form.

[0084] The raw material powder has small granule sizes, preferably granules with a particle size lower than 1 mm, in particular around 750 microns.

[0085] In an embodiment variant, not illustrated, the raw material powder is obtained on-site by arranging up a suitable grinding unit upstream of the mixing unit 10 to reduce the starting raw materials into powder.

[0086] The mixing unit 10 is shaped to receive a first amount of raw materials in powder form and a first amount of fat.

[0087] The mixing unit 10 preferably comprises a hopper 12 which feeds the subsequent cold pressing unit 30. The hopper 12 is preferably positioned in an upper area of the plant 1 which facilitates the subsequent conveying of the mixed material to the cold pressing unit 30 below by falling.

[0088] The mixing unit 10 is further equipped with conveyor means 14 of the raw material powder and fat to the hopper 12.

[0089] The conveyor means 14 preferably consist of a rotatable worm screw 14a, or auger.

[0090] The auger 14a transports the raw materials and fat from a loading area 15a, where they are mixed, to the hopper 12.

[0091] The fat used for the production of kibble A is preferably an animal fat and / or a vegetable fat. The function of the fat is to balance the nutritional content of the kibble A.

[0092] The fat used according to the present invention is in fluid, preferably liquid, form, considering the working room temperature. In other words, such fat has a melting point such that at room temperature it is in fluid form, preferably liquid.

[0093] The hopper 12 feeds the next and underlying cold pressing unit 30. The cold pressing unit 30 comprises a die 32 having a plurality of pressing holes 34 through which the product is mechanically pressed and slid to the respective outlets 36.

[0094] The cold pressing unit 30 is equipped with special pressing means 40 of the product to be mechanically pressed through said pressing holes 34.

[0095] According to an aspect of the present invention, the pressing holes 34 have a particular shape, as described in detail below. Reference will be made below to the description of one of said holes, it being clear that what is described for one hole can be extended to each of the other holes of the die 32.

[0096] According to the preferred embodiment illustrated and described, the die 32 has an annular shape extending around a central axis X where a hollow central part 33 delimited by the annular inner surface 32a of the die 32 is identified. The pressing holes 34 are preferably uniformly distributed along said die 12 and extend radially relative to the central axis X from said hollow central part 33.

[0097] Also according to the preferred embodiment illustrated and described, the die 32 is rotatable, in operation, about the central axis X. Suitable rotation means 35 allow the rotation of the die 32 and preferably comprise at least one power unit or gearmotor.

[0098] The pushing means 40 are preferably arranged at said central axis X of the die 32, in particular at the hollow central part 33 of the die 32.

[0099] Preferably the pushing means 40 comprise at least one roller 45a, 45b which radially pushes outwards the product to be mechanically pressed and against the die 32, in particular to said pressing holes 34. The figures depict a preferred embodiment wherein the pushing means 40 comprise a pair of rollers 45a, 45b side-by-side extending along respective rotation axes parallel to each other and to said central axis X.

[0100] In operation, the rotational movement of each roller 45a, 45b causes the product to be dragged on its outer surface and forcibly conveyed to said pressing holes 34. To facilitate the movement of the product, the outer surface of each roller 45a, 45b is non-smooth, preferably provided with ribs.

[0101] According to the preferred embodiment illustrated and described, the rollers 45a, 45b are mounted idle and the rotation movement is imparted to the rollers 45a, 45b by friction between the outer surface of each roller which is placed in contact with the inner annular surface 32a of the rotating die 32.

[0102] The speed and shape of the rollers 45a, 45b allow pressure to be exerted on the product to be mechanically pressed, with values around 20 tonnes per square centimetre.

[0103] Preferably, moreover, product conveyors 42 are also arranged between the hopper 12 and the pushing means 40. The conveyor means 42 preferably comprise a propeller 42a adapted to axial pushing the product coming from the hopper 12 towards the hollow central part 33 of the die 32.

[0104] With reference to the pressing hole 34, as shown in the detail of Figure 5, it extends longitudinally along a main axis Y. According to an aspect of the present invention, the length of the pressing hole 34 measured along the main axis Y is between 100 and 200 mm and the outlet area of the pressing hole 34 measured in a plane P perpendicular to the main axis Y is between 20 and 40 mm2. In a preferred embodiment, the length of the pressing hole 34 measured along the main axis Y is 150 mm and the outlet area of the pressing hole 34 is approximately 28 square millimetres.

[0105] The pressing hole 34 preferably comprises a first section 34a of a truncated cone shape and a second section 34b of a cylindrical shape on which the outlet 36 of the pressing hole 34 is identified. The mechanically pressed product exiting the pressing holes 34 therefore has a cylindrical shape.

[0106] The first section 34a of a truncated cone shape preferably has a taper of 30°, which facilitates the entry of a greater amount of product and favours processing speed.

[0107] In embodiment variants, the pressing hole 34 could have different shapes, e.g., have a single truncated cone section or have non-circular sections, e.g., polygonal or mixtilinear. The pressed product may therefore have a non-cylindrical shape, e.g., prismatic in the case of a polygonal section.

[0108] Furthermore, while the die 32 preferably has an annular shape, which optimises the number of pressing holes and the cold pressing efficiency, in embodiment variants the die may have different shapes, such as a flat shape to define a corresponding flat die.

[0109] The cutting unit 80 preferably comprises a blade or several blades 82 arranged at a predetermined distance D relative to the outer annular surface of the rotating die 32, where the outlets 36 of the cold pressing holes 34 are identified. The pressed product exiting the pressing holes 34 is therefore cut to a length which is according to the rotation speed of the rotating die 32 of said distance D and the number of blades 82 and their arrangement around the rotating die 32. A casing 60 preferably wraps the die 32 to collect and convey the cut product to a lower funnel-shaped collection portion 62. Preferably, a sieve 64 is positioned in the collection portion 62 or after it to ensure the passage of mechanically pressed product (kibble A) of the desired size. Furthermore, preferably, suction means 70 allow the removal of residual powder generated during the cutting step obtained by the cutting unit 80.

[0110] The plant 1 is also preferably equipped with aeration means 65 associated with the die 32. Preferably, the aeration means 65 are associated with the casing 60 and comprise one or more inlet holes 65a of a fluid.

[0111] In a first preferred form of using the aeration means 65, a cooling air flow of the cold pressing unit 30, in particular the die 32, is introduced inside the casing 60. This advantageously allows working temperatures to be maintained at desired values and with a desired degree of humidity, in particular according to the raw materials used and the amounts involved. For example, in the production of fish kibble using a high amount of fat, e.g., around 30%, it is advantageous to keep the temperature low to facilitate kibble compaction.

[0112] Preferably, the air introduction holes 65a are positioned in opposite positions around the central axis X with the effect of generating an air vortex at the die 32 which increases the cooling effectiveness thereof.

[0113] In another preferred form of using the aeration means 65, a flow of stream is introduced inside the casing 60.

[0114] The addition of steam during the mechanical pressing step has been proven to increase the production rate of the plant 1. In particular, this has the advantage that it allows the product to pass through the pressing holes 34 more quickly.

[0115] This has been verified, for example, in the production of cow kibble, which contains a great deal of fibrous raw materials and a low percentage of fat.

[0116] In a further preferred form of using the aeration means 65, both an air and steam flow is introduced inside the casing 60, with the aforementioned advantages.

[0117] The plant 1 described advantageously allows the implementation of the method for producing kibble A according to a preferred embodiment of the invention. In particular, the method for producing kibble A according to the invention comprises the steps of:

[0118] - preparing a mixture comprising a first amount QI of powdered raw materials;

[0119] - adding to said mixture a first amount G1 of fat, said first amount G1 of fat being present in a percentage between 10 and 30% relative to the first amount QI of raw materials, preferably such a first amount QI of raw materials and such a first amount G1 of fat being conveyed to the hopper 12 by means of the auger 14a;

[0120] - compacting the mixture of raw materials and the fat by means of a cold pressing process while maintaining the temperature at room temperature, preferably through said cold pressing unit 30;

[0121] - cutting the product obtained from the cold pressing process to size, preferably through a cutting unit 80, to obtain kibble A.

[0122] According to an aspect of the present invention, the initial step of preparing a mixture comprising a first amount QI of powdered raw materials requires the use of dehydrated raw materials with a relative humidity lower than 14%. More preferably, the mixture has a relative humidity of between 7 and 12%.

[0123] For this purpose, preferably, the plant 1 may comprise a drying unit upstream of the mixing unit 10 to dehydrate the raw material mixture to residual relative humidity values lower than 14%.

[0124] According to a first advantageous aspect, the method and plant 1 according to the invention adds the fat directly inside the raw material mixture in a step before their compaction / cold pressing. Advantageously, the fat in the kibble A is distributed inside the raw material mixture and is not arranged outside the kibble A, as is the case with known kibble types. This is due to the fact that the fat G1 remains trapped inside the kibble as the friction of the product as it passes inside the pressing hole 34 of the die 32 generates a hardened outer surface of the kibble A which retains the fat therein.

[0125] This allows to eliminate the amount of fat exposed to the external environment with corresponding elimination of problems related to oxidation and / or rancidity of the fat and deterioration of the kibble in the short term. This allows to avoid the use of additives, such as preservatives and chemical antioxidants, used in the production of known kibble types. Furthermore, the possibility of distributing the fat inside the kibble allows the use of a greater amount of fat, preferably between 10 and 30%, which is an optimal amount for the animal diet.

[0126] According to another advantageous aspect, the method and plant 1 according to the invention in which raw materials are used in powder form and dehydrated with low moisture values allows to improve the compression factor of the raw materials with each other and the agglomeration speed during the cold pressing process. In particular, said moisture values allow the cold pressing process at room temperature, avoiding the high working temperatures of the known systems. Advantageously, the nutrients contained in the raw materials used, such as vitamins and / or proteins, are not inactivated by high temperatures.

[0127] Furthermore, the improved compression factor allows to obtain an end product-kibble which occupies up to 50% less space relative to a similar known product.

[0128] In a further advantageous aspect, the shape of the pressing holes 34 of the die 32 and the working pressure with which the product is compressed through the holes 34 itself allows the cold pressing process to be carried out in fractions of a second and allows the compaction of the raw materials and fat at the above-mentioned low relative humidity values of the raw materials. Furthermore, the speed of the cold pressing process avoids the heating of the product typically caused by high friction against the walls of the pressing hole, keeping the working temperatures below 40°C.

[0129] The product / kibble A obtained by the method and plant 1 according to the invention also advantageously has a higher digestibility relative to the known types of kibble. The compactness of the kibble A made according to the invention gives it a consistency such as to easily crumble and dissolve in the animal's stomach, speeding up digestion time and improving the digestibility thereof relative to the known types of kibble.

[0130] The above shows how the method and / or plant and / or food according to the invention achieves the intended aims.

[0131] It must be understood that what described above has an exemplary and non-limiting purpose; therefore, possible variants of detail that may be necessary for technical and / or functional reasons, are considered from now falling within the same protective scope defined by the hereinafter reported claims.

Claims

CLAIMS1. Method for producing animal food (A) characterised in that it comprises the steps of:- preparing a mixture comprising an amount (QI) of dehydrated and powdered raw materials so that said mixture of said raw materials has a relative humidity lower than 14%;- adding to said mixture of said raw materials an amount (Gl) of fat, said amount (Gl) of fat being present in a percentage of between 10 and 30% relative to said amount (QI) of raw materials;- compacting said mixture and said fat by means of a cold pressing process while maintaining the temperature at room temperature values;- cutting the product obtained from said cold pressing process to size.

2. Method according to claim 1, characterised in that said mixture of said raw materials has a relative humidity of between 7 and 12%.

3. Method according to claim 1 or 2, characterised in that said amount (Gl) of fat is present in a percentage of between 14 and 15% relative to said amount (QI) of raw materials.

4. Method according to any one of the preceding claims, characterised in that said raw materials comprise meat and / or fish and / or fruit and / or vegetables.

5. Method according to any one of the preceding claims, characterised in that said powdered raw materials have a particle size lower than 1 mm, in particular around 750 microns.

6. Method according to any one of the preceding claims, characterised in that said fat comprises animal fat and / orvegetable fat.

7. Method according to any one of the preceding claims, characterised in that said fat has a melting point such that at room temperature it is in a fluid, preferably liquid, form.

8. Method according to any one of the preceding claims, characterised in that said cold pressing process has a duration lower than 6 seconds.

9. Plant (1) for the production of an animal food (A) characterised in that it comprises:- a mixing unit (10) adapted to receive an amount (QI) of dehydrated and powdered raw materials and an amount (Gl) of fat;- a cold pressing unit (30) comprising a die (32) comprising at least one pressing hole (34) extending longitudinally along a main axis (Y), wherein the length of said pressing hole (34) measured along said main axis (Y) is between 100 and 200 mm and wherein the outlet surface area of said pressing hole (34) measured in a plane perpendicular (P) to said main axis (Y) is between 20 and 40 mm2;- a cutting unit (80) arranged downstream of said cold pressing unit (30) for cutting to size the product mechanically pressed by said die (32).

10. Plant (1) according to claim 9, characterised in that said length of said pressing hole (34) is 150 millimetres.

11. Plant (1) according to claim 9 or 10, characterised in that said outlet surface area of said pressing hole (34) measured in said plane perpendicular to said main axis (Y) is equal to 28 square millimetres.

12. Plant (1) according to any one of claims 9 to 11, characterised in that said pressing hole (34) comprises a first section (34a) of a truncated cone shape and a second section (34b) of a cylindricalshape on which the outlet of said pressing hole (34) is identified.

13. Plant (1) according to any one of claims 9 to 12, characterised in that said cold pressing unit (30) comprises means for pushing (40) the product to be mechanically pressed through said at least one pressing hole (34).

14. Plant (1) according to any one of claims 9 to 13, characterised in that said die (32) has an annular shape which extends around a central axis (X) and comprises a plurality of pressing holes (34).

15. Plant (1) according to claim 14, characterised in that said annular die (32) is rotating.

16. Plant (1) according to claim 14 or 15, characterised in that said pressing holes (34) extend radially relative to said central axis (X) in said die (32) and said pushing means (40) of the product to be mechanically pressed are arranged at said central axis (X) of said die (32).

17. Plant (1) according to claim 16, characterised in that said pushing means (40) comprise one or more rollers (45a, 45b) adapted to radially push outwards said product to be mechanically pressed and against said die (32).

18. Plant (1) according to any one of claims 9 to 17, characterised in that said mixing unit (10) comprises a hopper (12) for feeding said die (32) and is adapted to receive said dehydrated and powdered raw materials and said fat.

19. Plant (1) according to any one of claims 9 to 18, characterised in that said mixing unit (10) comprises conveyor means (14) for conveying said dehydrated and powdered raw materials and said fat to said hopper (12).

20. Plant (1) according to claim 19, characterised in that saidconveyor means (14) comprise a rotatable worm screw (14a).

21. Plant (1) according to any one of claims 9 to 20, characterised in that it further comprises a grinding unit arranged upstream of said mixing unit (10) to reduce raw materials into powder.

22. Plant (1) according to any one of claims 9 to 21, characterised in that it further comprises a drying unit arranged upstream of said mixing unit (10) to dehydrate said mixture of said raw materials to residual relative humidity values lower than 14%.

23. Plant (1) according to any one of claims 9 to 23, characterised in that it further comprises aeration means (65) for conveying air and / or steam to said die (32).

24. Animal food (A) obtained by a cold pressing process, comprising:- a mixture comprising an amount (QI) of raw materials;- an amount (Gl) of fat, wherein said amount (Gl) of fat is between 10 and 30% relative to said amount (QI) of raw materials and said fat is distributed internally in said mixture of said raw materials.

25. Food (A) according to claim 24, characterised in that said amount (Gl) of fat is present in a percentage of between 14 and 15% relative to said amount (QI) of raw materials.

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