Method for producing a food product, food product and apparatus

Abstract

A method for producing food products for human consumption using extrusion from less expensive parts of fish material is disclosed. The method includes the steps of providing a fish material containing hard tissue, optionally providing a stabilizing material, optionally grinding the fish material in a grinder with a hole diameter of up to 2 mm to provide fish chunks, performing a first colloidal grinding of the fish material to provide colloidal-ground fish chunks, extruding the colloid-ground fish chunks to provide extruded fish chunks, and performing a second colloidal grinding of the extruded chunks to provide colloid-ground extruded fish chunks as the food product.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a food product. In particular, the present invention relates to a method for producing food products by extrusion from fish material, including less expensive parts of the fish. The present invention also relates to food products produced by the methods of the present invention. [Background technology]

[0002] Extrusion is widely used in the manufacture of a variety of food products. Generally speaking, extrusion is a continuous process using an extruder with one or two screws. Extruders provide the transport, compression, mixing, cooking, shearing, heating, cooling and shaping of raw materials into a final product.

[0003] Anni Nisov et al., Comparison of Whole and Gutted Baltic Herring as a Raw Material for Restructured Fish Product Produced by High-Moisture Extrusion Cooking, Foods 2020, 9 1541, pp. 1-12, discloses the microbiological safety, sensory and structural properties of whole, gutted and gutted fish in high-moisture extrusion cooking incorporating vegetable proteins. Summary of the Invention [Means for solving the problem]

[0004] It has now been found that human food products with satisfactory organoleptic properties, such as appealing taste and texture, can be produced by extrusion from less expensive parts of fish material without the use of stabilizing materials. The fish material may be whole fish or gutted fish, or hard tissue fish material only. The present invention therefore provides a method for producing high value food products with consumer acceptable organoleptic properties from low cost fish material.

[0005] In the context of the present invention, the term "free of stabilizing materials" means that the food product does not contain vegetable protein materials, animal protein materials, egg proteins, vegetable carbohydrate materials, vegetable fiber materials or any mixture of said materials.

[0006] The present invention provides a sustainable method for the efficient use of whole or gutted fish in the production of ready-to-consume food products for human consumption, providing environmental benefits.

[0007] The present invention also provides an economic benefit in that products can be prepared at lower cost, providing a method in which undervalued parts of fish material or of lower hygiene quality can be used.

[0008] The present invention further provides a method for producing a nutritionally enhanced food product.

[0009] Additionally, the present invention provides a method for producing food products that allows for a reduction in global meat production, providing environmental benefits.

[0010] The present invention also provides a method for producing a food product of high microbiological quality that is substantially free of Salmonella bacteria.

[0011] The food product can be used as an ingredient or bulking agent and combined with other food ingredients to produce a variety of food compositions.

[0012] The food products produced by the methods of the present invention are also suitable as animal feed.

[0013] In one aspect, the present invention provides a method for producing a food product from fish material, including less expensive parts of the fish, without the use of stabilizing materials.

[0014] In one aspect, the present invention provides a food product obtainable by the method of the present invention.

[0015] In one aspect, the present invention provides a food product comprising a fish material including fish bones, wherein the calcium content of the food product is in the range of about 0.2% to about 4.0% by weight.

[0016] In a further aspect, the present invention provides a food product produced by the method of the invention or a food composition comprising a food product of the invention.

[0017] In one aspect, the present invention provides the use of a food product of the present invention or a food product produced by a method of the present invention in a food composition.

[0018] In a further aspect, the present invention provides an apparatus comprising means for carrying out the method of the present invention. [Brief explanation of the drawings]

[0019] [Figure 1] 1 shows a schematic process flow diagram of one embodiment of the method of the present invention. [Figure 2] 1 shows a schematic process flow diagram of another embodiment of the method of the present invention. [Figure 3] 1 illustrates an embodiment of the device of the present invention. [Figure 4] 2 shows another embodiment of the device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] In one aspect, the present invention provides a method of producing a food product, comprising: - providing fish material containing hard tissue; - optionally providing a stabilizing material; - optionally grinding the fish material using a grinder with a hole diameter of up to 2 mm to provide fish chunks; - subjecting the fish material to a first colloidal milling to provide colloidal milled fish chunks; - extruding the colloid-comminuted fish chunks to provide extruded fish chunks; - subjecting the extruded fish chunks to a second colloidal milling to provide colloidal milled extruded fish chunks as a food product. The present invention provides a method comprising:

[0021] FIG. 1 illustrates one embodiment of the method of the present invention. FIG. 2 illustrates another embodiment of the method of the present invention. The dotted lines in Figures 1 and 2 indicate optional method steps. These methods may include additional optional method steps not shown.

[0022] Fish material suitable for use in the method of the present invention includes any fish species suitable for human consumption, for example salmon or Baltic herring. In one embodiment, the fish material is whole fish or gutted fish. In one embodiment, the fish material comprises hard fish tissue, i.e., fish bones, scales, heads or fins. In one embodiment, the fish material consists of hard tissue selected from fish bones, scales, heads, fins and any mixture thereof. In one embodiment, the fish material includes at least bone. The fish material may also comprise or consist of skin. In one embodiment, the fish material contains up to about 90% by weight of hard tissue selected from fish bones, scales, heads and fins. In one embodiment, the fish material contains about 30% to about 90% hard tissue by weight.

[0023] In the method, fish material including hard tissue is optionally ground in a grinder with a hole diameter of up to 2 mm to provide fish chunks.

[0024] In one embodiment, the method of the present invention includes a pH adjustment step. In one embodiment, the pH of the fish material is adjusted to about 2 to about 6 with a food-grade acid. The food grade acid can be citric acid. In one embodiment, the pH adjustment step is carried out prior to extrusion.

[0025] The fish material is subjected to a first colloid milling step to break down the particles contained in the fish material into smaller pieces. Generally, a "colloid mill" is a machine with a high speed rotor and stator that provides an ultra-fine grinding result while simultaneously emulsifying, homogenizing, and dispersing. The rotor forces the material into the small gap between the rotor and the stator, causing powerful mechanical shear. In the present invention, colloidal milling provides homogeneous, ultra-fine bone particles of bone-containing fish chunks, which beneficially facilitates softening of the bone particles during subsequent wet extrusion. In one embodiment, colloidal milling of fish chunks provides bone particles with an average particle size of greater than 50 μm to about 200 μm. However, individual particles of larger size may also be present.

[0026] In one embodiment of the method of the present invention, a food product is produced that does not contain a stabilizing material. In another embodiment, the method of the present invention comprises the step of including a stabilizing material in the food product. The stabilizing material is utilized to stabilize the extrusion process so that substantial separation of water, oil, and solid materials in the mixture of colloidal comminuted fish chunks and stabilizing material is not observed during extrusion. In one embodiment, the stabilizing material comprises a vegetable protein material, an animal protein material, an egg protein, a vegetable carbohydrate material, a vegetable fiber material, or a mixture of any of the foregoing materials. In one embodiment, the stabilizing material is in powdered form. In one embodiment, the stabilizing material is fish meal. In another embodiment, the stabilizing material is a soy protein concentrate.

[0027] The stabilizing material used in the methods of the present invention exhibits a water holding capacity (WHC) of from about 0.5 g / g of dry stabilizing material to about 13 g / g of dry stabilizing material.

[0028] Water retention was measured as follows. Weigh the centrifuge bottle. Place 15 g of the dry stabilizing material and 60 g of distilled water in a centrifuge bottle. The bottle is placed on a shaker and shaken at 300 rpm for 5 minutes, then centrifuged at 2800 rpm for 20 minutes. The supernatant is decanted and the bottle is weighed. The water holding capacity of the stabilized material is calculated as a percentage based on the dry weight of the stabilized material.

[0029] In embodiments where a stabilizing material is not utilized in the method, the colloidal comminuted fish chunks are extruded to provide a solid extruded fish chunk.

[0030] In embodiments in which a stabilizing material is utilized in the method, the stabilizing material is added to the colloidally pulverized fish mass. The colloidal comminuted fish chunks containing the stabilizing material are then subjected to extrusion to provide extruded fish chunks.

[0031] The colloidal pulverized fish chunks contain about 1% to about 50% by weight of the stabilizing material based on the weight of the colloidal pulverized fish chunks. In another embodiment, the colloidal pulverized fish mass contains from about 1% to about 15% by weight of the stabilizing material.

[0032] In one embodiment, the extrusion is carried out at a moisture content of at least 20%. In one embodiment, the extrusion is wet extrusion to provide an extruded mass. In the context of the present invention, the term "wet extrusion" means that the colloidal comminuted fish mass, optionally containing stabilizing materials, that is extruded has a moisture content of at least 30%. In one embodiment, the moisture content is in the range of 30% to about 70%. If the moisture content is lower than 30%, it may be difficult to carry out the extrusion process due to the dryness of the colloidal ground fish chunks in the extruder. On the other hand, if the moisture content is higher than 70%, the liquid may separate improperly from the dry matter of the colloidal crushed fish chunks.

[0033] Extrusion can be carried out in a single or twin screw extruder. The combination of shear and tearing in the extrusion step with moisture causes softening of the hard tissues of the fish and provides a unique structure to the final food product.

[0034] In one embodiment, the extrusion is carried out at a temperature of from about 100°C to about 400°C. Depending on the extruder used in the process, the extruder must include at least one heating segment having a temperature of at least 100°C. Additionally, there may be a further heating segment in which extrusion may be carried out at less than 100°C, for example 70°C. In one embodiment of the present invention, an extruder is used that includes multiple heating segments, each operating at a different temperature. In one embodiment, the temperature of the heating segment increases as the mass moves forward in the extruder.

[0035] The duration of the extrusion step depends on the construction and settings of the equipment.

[0036] In one embodiment, the extrusion in the present method is carried out using a speed of about 100 rpm to about 1000 rpm. In another embodiment, the extrusion is carried out using a speed of about 200 rpm to about 600 rpm. In one embodiment, about 500 rpm is utilized in the extrusion.

[0037] In one embodiment, the extrusion provides an extruded mass at a temperature of at least 100°C.

[0038] In one embodiment, the extruded mass is cooled to a temperature of about +60°C to about -30°C. In one embodiment, cooling of the extrusion mass takes place within the extruder before the mass is discharged from the extruder. Cooling in the extruder is conveniently carried out in a cooling die. When the extruded mass is cooled within the extruder, the temperature of the mass exiting the extruder can range from about 1°C to about 80°C, or from about 1°C to about 60°C. In one embodiment, the temperature of the extruded mass is in the range of about 30°C to about 60°C.

[0039] In another embodiment of the present invention, colloidal comminuted fish chunks, optionally containing stabilizing materials, in an extruder are forced through holes in the end of the extrusion cylinder that may be equal to or smaller than the cylinder area. If the temperature exceeds 100°C, the extruded mass loses some of the water vapor when it leaves the process. The mass will have a different taste, smell, structure (viscosity, cutting properties, etc.) compared to processes that include a cooling die step, and will react differently in post-processing.

[0040] Extrusion of the colloidally comminuted fish chunks, optionally containing a stabilizing material, provides a solid extruded fish chunk which is further subjected to a second colloidal comminution to further break up the particles in the extruded chunks and improve the sensory properties of the resulting food product. The second colloidal milling may be the same as or different from the first colloidal milling. In one embodiment, water and / or oil is added to the extruded mass prior to colloidal milling to enhance the chopping effect of the colloidal milling.

[0041] Secondary colloidal comminution of the solid extruded fish mass provides a ready-to-consume food-grade product with attractive sensory properties. The double colloidally milled food product has a smooth texture with no visible bone particles present. The food product has an average particle size of up to 50 μm. In one embodiment, the average particle size is in the range of about 25 μm to about 50 μm. In another embodiment, the average particle size is in the range of about 1 μm to about 15 μm.

[0042] The extrusion process reduces the microbial load of the fish material, allowing the use of fish of lower hygiene quality. The microbial load increases during the process by approximately 1000-10 12 double decrease.

[0043] The extruded food products produced by the methods of the present invention can mimic the texture, flavor, and mouthfeel of meat.

[0044] The methods of the present invention provide food products that exhibit increased nutritional value. By using the calcium-containing part of the fish material, namely the bone, the calcium content of the food product produced by this method is increased. In one embodiment, the food product has a calcium content of about 0.2% to about 4.0% by weight. In another embodiment, the calcium content of the food product is from about 0.3% to about 2.0% by weight. In a further embodiment, the calcium content of the food product is from about 1.2% to about 1.5% by weight.

[0045] The method of the present invention provides a food product having a protein content of about 5% to about 30% by weight, a fat content of about 2% to about 30% by weight, a dry matter content of about 30% to about 70% by weight, and a pH of about 3 to about 7.5.

[0046] In one embodiment, the food product is heat treated at a temperature ranging from about 110° C. to about 400° C. to further improve the sensory properties and texture of the product. Heat treatment can be carried out, for example, by cooking in oil at, for example, 150-300°C, grilling, pan-frying, drying by heat at, for example, 200-400°C, freeze-drying at -70°C or below, microwave heating or infrared irradiation.

[0047] Heat treatment coupled with extrusion of fish material, such as whole fish, containing valuable parts such as fish bones and other hard tissues, provides ready-to-eat food products for human consumption that exhibit unique and attractive taste and structure and texture.

[0048] The sensory properties of the food product may be further improved by adding ingredients commonly used in food manufacturing, such as flavorings, aromas, salt, emulsifiers, carbohydrates, fiber, oils and fats, to the food product produced by the method of the present invention.

[0049] The extruded food products produced by the methods of the present invention can be combined with other food ingredients to provide a variety of food compositions that differ in appearance, taste and structure. Thus, in one aspect, the present invention provides the use of a food product produced by the method of the present invention as an ingredient or bulking agent in the production of a food composition. The food products produced by the methods of the present invention may be included in foodstuffs in amounts up to about 50% by weight without any adverse effect on the sensory properties of the food composition.

[0050] In one embodiment, the food product is mixed with water in a 3:1 (w / w) ratio to provide moist fish chunks. Salt may be added to the moist fish mass to provide, for example, about 2% salt by weight of the mass. The moist fish chunks can then be added to the fish fillets by needling them into the fish fillets, for example in a ratio of 1:10 (w / w). The injection is suitably carried out in several injection steps.

[0051] In another aspect, the present invention provides a food product comprising a fish material including fish bones, wherein the calcium content of the food product is in the range of about 0.2% to about 4.0% by weight. In another embodiment, the calcium content of the food product is from about 0.3% to about 2.0% by weight. In a further embodiment, the calcium content of the food product is from about 1.2% to about 1.5% by weight.

[0052] The food product of the present invention has a protein content of about 5% to about 30% by weight. The fat content of the food product is from about 2% to about 30% by weight. The dry matter content of the food product is about 30% to about 70% by weight. The pH of the food product is from about 3 to about 7.5.

[0053] In another aspect, the present invention provides a food product produced by the method of the present invention or a food composition comprising a food product of the present invention.

[0054] In a further aspect, the present invention provides an apparatus for carrying out the method of the present invention, comprising means for carrying out the method of the present invention. One embodiment of the device of the present invention is shown in FIG. Another embodiment of the device of the present invention is shown in FIG. The dotted lines indicate arbitrary units. The device may include further optional units not shown.

[0055] In one embodiment, the means - Any meat grinder for grinding fish ingredients to provide fish chunks; - a first colloid mill optionally connected to the meat grinder and configured to receive the fish chunks; an extruder connected to the first colloid mill and configured to receive the colloid-ground fish mass and provide an extruded mass; - a second colloid mill connected to the extruder and configured to receive the extruded mass and provide the food product; Includes:

[0056] The following examples are presented to further illustrate the invention without limiting it thereto.

[0057] The calcium content of the food products was determined according to the standard SFS-EN ISO11885, 2009.

[0058] The level of aerobic microorganisms was determined according to standard NMKL86:2013.

[0059] Salmonella levels were determined according to ISO / DIS20976-2.

[0060] Example 1 100 kg of fish (gutted salmon) containing a total of approximately 90% head, scales and fins, and 10% muscle mass was colloidally ground into fine fish chunks with hard tissue particles approximately 100 μm in diameter.

[0061] The microfish chunks were kept at approximately 4°C. The mass was then dumped into a silo connected to a conveyor screw connected to a hopper of approximately 30 litres capacity. The mass was led from the hopper by an auger and screw to the extruder in a controlled manner at about 55 kg / h. The moisture content of the mass was about 65% by weight. The mass was extruded at 170 rpm. The heating zones of the extruder were adjusted to temperatures of 60°C, 70°C, 80°C, 100°C, 120°C, 150°C and 170°C.

[0062] The extruder was provided with a cooling die. The first zone of the cooling die was set at 35°C and the last zone was set at 35°C. The extrusion process took approximately 1 minute.

[0063] The extruded solid fish chunks exited the cooling die at a temperature below 100°C. Only small amounts of vapor were released in the process. Solid fish chunks and some amount of separated oil exited the end of the cooling die.

[0064] The levels of aerobic microorganisms in the solid fish mass obtained from the extrusion were measured at 30°C / 72h. The extruded fine fish chunks exhibited over 1,000,000 pmy / g, whereas the solid fish chunks exhibited less than 100 pmy / g. The levels of aerobic microorganisms measured indicate that a food-grade product for human consumption has been obtained.

[0065] Water was added to each solid fish chunk in a ratio of 1:10 (w / w), and the mixture was left at 30°C for 20 minutes to be absorbed into the chunks and mixed. The batches of mass were then milled in a colloid mill. Colloidal milling provided comminuted fish chunks, a ready-to-consume food product with attractive sensory properties.

[0066] The food product had a calcium content of 2% by weight.

[0067] The food products showed a 7-log reduction in Salmonella, indicating complete elimination of Salmonella.

[0068] Colloidal ground fish chunks were mixed with water in a 3:1 (w / w) ratio to provide hydrous fish chunks. Salt was added to provide a moist fish mass containing 2% salt by weight. The moist fish chunks were added to the salmon fillets at 2°C by needle insertion into the salmon fillets in a ratio of 1:10 (w / w) in a total of 50 separate injection steps.

[0069] Example 2 80 kg of fish (gutted salmon) containing a total of approximately 70% bones, heads, scales and fins and 10% skin was minced in a meat grinder with 2 mm holes. The ground mass was then colloidally milled into fine fish mass with hard tissue particles having a diameter of approximately 100 μm.

[0070] The crushed fish chunks were mixed properly with 20 kg of fish meal powder (Baltic herring with a protein content of 66% by weight). The WHC of the fish meal powder was 2.2 g per 1 g of dry stabilized material. The resulting mixture was kept at approximately 4°C. The mixture was then poured into a silo connected to a conveyor screw connected to a hopper of approximately 30 litres capacity. The mixture was directed from the hopper by an auger and screw into the extruder in a controlled manner at about 55 kg / h.

[0071] The mixture of ground fish chunks and fish meal powder was introduced into an extruder with an integrated cooling die. The moisture content of the mixture was about 55% by weight. The mixture was extruded at 170 rpm. The heating zones of the extruder were adjusted to temperatures of 60°C, 70°C, 80°C, 100°C, 120°C, 150°C and 170°C. The first zone of the cooling die was set at 35°C and the last zone was set at 35°C. The extrusion process took approximately 1 minute.

[0072] The extruded solid mass exited the cooling die at a temperature below 100°C. Only small amounts of vapor were released in the process. A solid mass and some amount of separated oil exited the end of the cooling die.

[0073] The level of aerobic microorganisms in the solid mass obtained from the extrusion was measured at 30°C / 72h. The extruded mixture exhibited over 1,000,000 pmy / g, while the solid mass exhibited less than 100 pmy / g. The levels of aerobic microorganisms measured indicate that a food-grade product for human consumption has been obtained.

[0074] The food product, ie the solid extruded mass, had a calcium content of 1.2% by weight.

[0075] The solid mass showed a 7-log reduction in Salmonella, indicating complete elimination of Salmonella.

[0076] The solid mass was ground in a meat grinder with holes of 2 mm diameter. Both sunflower oil and water were added to the ground mass in a ratio of 2:10 (w / w) respectively and left at 4°C for 60 minutes to be absorbed into the mass. The batch of chunks was then milled in a colloid mill. Colloidal milling provided a milled mass that was a ready-to-consume food product with attractive sensory properties.

[0077] The ground mass may also be used as an ingredient in a food composition in an amount of up to 50% by weight of the total weight of the food composition.

[0078] Example 3 Extruded mass was produced in a similar manner to Example 2, except that 80 kg of gutted salmon head and fish bones and some muscle mass were used. Instead of fish meal powder, soy protein concentrate with a protein content of 66 wt% and a WHC of 4.5 g per g of dry stabilizing material was used as raw material.

[0079] The pH of the fish mass was adjusted to 5 by adding 10% aqueous citric acid to the mass.

[0080] The colloidal milled extruded mass was torn into particles with a particle size of approximately 1-5 mm. Fresh salmon fillet was added to the particles in a ratio of 85:15 (w / w), followed by 10% boiled potato chunks. The resulting mixture was ground in a meat grinder equipped with a 5 mm sieve to provide a dough.

[0081] To the dough was added 2.0% by weight of salt and spices including black pepper powder, chili powder, cumin powder, garlic powder, onion powder and dill. The dough was kneaded for about 20 minutes until a smooth mass was obtained. The mass was formed into 5cm balls, placed on oiled aluminium foil and baked in an oven at 200°C for approximately 15 minutes, until the internal temperature of the kebab-like mass reached 80°C.

[0082] The product was cooled to +4°C and vacuum packed.

[0083] The resulting fishball-like food product exhibited an appealing taste and texture.

[0084] Example 4 100 kg of fresh rainbow trout (Oncorhynchus mykiss), including head and spine, totaling approximately 70% of the hard tissue, was minced in a meat grinder with a hole diameter of 2 mm. The ground mass was then colloidally milled into fine fish mass.

[0085] The colloidal milling mixture was kept at approximately 4°C. The mixture was then poured into a silo connected to a conveyor screw connected to a hopper of approximately 30 litres capacity. The mixture was directed from the hopper by an auger and screw into the extruder in a controlled manner at about 30 kg / h.

[0086] The mixture was directed into an extruder equipped with an integrated cooling die. The water content of the mixture was about 50% by weight. The mixture was extruded at 130 rpm. The heating zones of the extruder were adjusted to temperatures of 60°C, 70°C, 80°C, 120°C, 150°C, 160°C and 180°C. The first zone of the cooling die was set at 30°C and the last zone was set at 30°C. The extrusion process took approximately 1 minute.

[0087] The extruded solid mass exited the cooling die at a temperature below 100°C. Only small amounts of vapor were released in the process. A solid mass and some amount of separated oil exited the end of the cooling die.

[0088] The level of aerobic microorganisms in the solid mass obtained from the extrusion was measured at 30°C / 72h. The extruded mixture exhibited over 1,000,000 pmy / g, while the solid mass exhibited less than 100 pmy / g. The levels of aerobic microorganisms measured indicate that a food-grade product for human consumption has been obtained.

[0089] The solid mass showed a 7-log reduction in Salmonella, indicating complete elimination of Salmonella.

[0090] Both rapeseed oil and water were added to the ground mass in a ratio of 1:15 (w / w) respectively and mixed mechanically. The batch of chunks was then milled in a colloid mill. Colloidal milling provided a milled mass that was a ready-to-consume food product.

[0091] The composition of the ready-to-consume food product was as follows: calcium 1.3 wt% (CP-MS: SFS-EN ISO11885, 2009; NMKL1616, 1998), fat 24 wt% (AOAC n:o922.06(LA1004P)(TL95)), carbohydrate 0%, protein 14 wt% (SFS-EN ISO14891:2002; SFS-EN ISO16634-1:2009; SFS-EN), sodium 0.1 wt% (SFS-EN ISO11885, 2009; NMKL161, 1998 (TL25), ash content 3% by weight (NMKL173 / 2005(LA1007P)(TL95)), moisture 55% by weight (NMKL169:2002(LA1005P)(TL95)), energy content 1200kJ / 100g.

[0092] The food product may also be used as an ingredient in a food composition in an amount of up to 70% by weight of the total weight of the food composition.

[0093] It will be obvious to those skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above, but may vary within the scope of the claims.

Claims

1. 1. A method of producing a food product, comprising: - providing fish material containing hard tissue; - optionally providing a stabilizing material; - optionally grinding said fish material in a grinder with a hole diameter of maximum 2 mm to provide fish chunks; - subjecting said fish material to a first colloidal milling to provide colloidal milled fish chunks; - extruding said colloid-comminuted fish chunks to provide extruded fish chunks; - subjecting said extruded fish chunks to a second colloidal milling to provide colloidal milled extruded fish chunks as a food product.

2. 10. The method of claim 1, wherein the fish material containing hard tissue is whole ungutted or gutted fish containing at least one of fish bones, scales, heads, and fins.

3. 3. The method according to claim 1 or 2, wherein the fish material contains up to 90% by weight, in particular from about 30% to about 90% by weight, of hard tissue selected from fish bones, scales, heads and fins.

4. The method according to any one of claims 1 to 3, wherein the fish material contains fish bones.

5. 5. The method according to any one of claims 1 to 4, wherein the stabilising material is selected from a vegetable protein material, an animal protein material, an egg protein, a vegetable carbohydrate material, a vegetable fibre material and any mixture of said materials.

6. The method according to any one of claims 1 to 5, wherein the stabilizing material is a powder.

7. The method according to any one of claims 1 to 6, wherein the stabilising material is fish meal or soy protein concentrate.

8. 8. The method of any one of claims 1 to 7, wherein the first colloidal milling provides colloidal milled fish chunks comprising particles greater than 50 μm up to about 200 μm in size.

9. The method of any one of claims 1 to 8, wherein a food product is produced that does not contain stabilizing materials.

10. 9. The method according to any one of claims 1 to 8, wherein the stabilising material is provided to and added to the colloidal comminuted fish mass before the extrusion.

11. 11. The method of claim 10, wherein the stabilizing material is added in an amount of about 1% to about 50% by weight, in particular about 1% to about 15% by weight, based on the weight of the colloidal-ground fish mass.

12. 12. The method according to any one of claims 1 to 11, wherein the extrusion of the colloidal-comminuted fish mass is carried out at a moisture content of at least 20%, in particular in the range of about 30% to about 70%.

13. The method of any one of claims 1 to 12, wherein the pH is adjusted to about 2 to about 6 with a food grade acid prior to extrusion.

14. The method of any one of claims 1 to 13, wherein the extrusion is carried out at a temperature of from 100°C to about 400°C.

15. A method according to any one of the preceding claims, wherein the temperature of the extruded mass is at least 100°C.

16. 16. The method according to any one of claims 1 to 15, wherein the extrusion is carried out using a speed of about 100 rpm to about 1000 rpm, in particular a speed of about 200 rpm to about 600 rpm, more particularly about 500 rpm.

17. 17. The method according to any one of claims 1 to 16, wherein the food product has an average particle size of up to 50 μm, in particular between about 25 μm and 50 μm, more particularly between about 1 μm and about 15 μm.

18. 18. The method according to any one of claims 1 to 17, wherein the food product has a calcium content of from about 0.2% to about 4.0% by weight, in particular from about 0.3% to about 1.5% by weight, and more particularly from about 1.2% to about 1.5% by weight.

19. 19. The method of any one of claims 1 to 18, wherein the food product has a water holding capacity (WHC) of from about 0.5g per gram of dry stabilizing ingredient to about 13g per gram of dry stabilizing ingredient.

20. The food product has the following characteristics: a protein content of about 5% to about 30% by weight; - a fat content of from about 2% to about 30% by weight; - About 30% to about 70% by weight of dry matter, - pH about 3 to about 7.5 The method according to any one of claims 1 to 19, comprising at least one of:

21. A food product obtainable by the method according to any one of claims 1 to 20.

22. 1. A food product comprising a fish material, including fish bones, wherein the calcium content of the food product is in the range of about 0.2% to about 4.0% by weight, particularly about 0.3% to about 1.5% by weight, and more particularly about 1.2% to about 1.5% by weight.

23. 23. The food product according to claim 22, wherein the food product has an average particle size of up to 50 μm, in particular between about 25 μm and 50 μm, more particularly between about 1 μm and about 15 μm.

24. 24. The food product of any one of claims 22 to 23, wherein the food product has a water holding capacity (WHC) of from about 0.5g to about 13g per gram of dry stabilizing ingredient.

25. The food product has the following characteristics: a protein content of about 5% to about 30% by weight; - a fat content of from about 2% to about 30% by weight; - About 30% to about 70% by weight of dry matter, - pH about 3 to about 7.5 The food product according to any one of claims 22 to 24, having at least one of:

26. 26. Use of a food product according to any one of claims 21 to 25 or a food product produced by a method according to any one of claims 1 to 20 in a food composition.

27. A food product produced by the method of any one of claims 1 to 20 or a food composition comprising the food product of any one of claims 21 to 25.

28. Apparatus comprising means for carrying out the method according to any one of claims 1 to 20, said means comprising: - an optional meat grinder for grinding the fish material to provide fish chunks; a first colloid mill, optionally connected to said meat grinder and adapted to receive said fish chunks; an extruder connected to the first colloid mill and configured to receive the colloid-ground fish chunks and provide an extruded chunk; a second colloid mill connected to said extruder and configured to receive said extruded mass and provide a food product; 1. An apparatus comprising:

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