Methods for producing animal-derived proteins

Abstract

[Problem] Provided is a production method that is for animal-derived protein and that is capable of efficiently producing fish protein collected through separation from bones. [Solution] The present invention comprises: an enzyme addition step for chopping raw materials including fish and / or process residues thereof, and adding an enzyme liquid thereto; a pressure reduction step for performing, at least once, a reduced pressure / atmospheric pressure operation of subjecting the raw materials processed in the enzyme addition step to vacuum decompression, evaporating water in the raw material, and thereafter, restoring the pressure to atmospheric pressure; an enzymatic degradation step of allowing the mixture to stand at an optimum temperature and an optimum pH for an enzymatic reaction by the enzyme liquid for a predetermined period of time; an enzyme inactivation step for increasing the temperature of the mixture to 90-95°C to inactivate the enzyme in the enzyme liquid at a high temperature; and a bone-meat separation step for, after the enzyme is inactivated, collecting protein of the raw materials by separating the protein from bones using a bone-meat separation device.

Description

[Technical field]

[0001] The present invention relates to a method for producing animal-derived proteins, in particular, a method for producing fish proteins separated from bones. [Background technology]

[0002] It is predicted that in 2050, the world will face a serious crisis of protein supply shortages and climate change. For this reason, the British medical journal "Lancet" published a paper on January 16, 2019, proposing to increase blue foods (animals, plants, algae, etc. originating from marine and freshwater environments) to support the diet of the world population, which is expected to reach 10 billion people by 2050 (see, for example, Non-Patent Document 1). In addition, the EAT-Lancet Committee has stated that in order to provide healthy diets to the world's people, who are said to reach approximately 10 billion people in 2050, and to achieve the "Sustainable Development Goals (SDGs)" and the "Paris Agreement", it is necessary to switch to a healthy diet with a sustainable food system. Furthermore, a paper was published in Nature magazine on September 15, 2021, suggesting that the quality of the diet may be improved by increasing the consumption of blue foods (see, for example, Non-Patent Document 2).

[0003] In 2018, the total production of fishery products in the world was 178.5 million tons, of which 156.4 million tons was used for human consumption, and 22 million tons was used for fish meal, fish oil, and other purposes. Of the fishery products used for human consumption, 45% were fresh, 31% were frozen, 12% were salted and dried, and 12% were other processed products.

[0004] In 2018, the world's marine fish catch was 84.4 million tons, of which fish accounted for 71.93 million tons. The top-ranked South American anchovy (7 million tons) and fifth-ranked European blue whiting (1.71 million tons) are mostly used for fish meal due to their small bodies, while the second-ranked Alaska pollock (3.4 million tons) is mainly used as a raw material for fillets and surimi, resulting in a large amount of what is called "residue" such as heads, fins, skin, backbone, and scales (see, for example, Non-Patent Document 3).

[0005] Fish waste and waste are generated throughout the entire distribution process from fish landing to consumption. Specifically, they occur at three stages: the landing production area stage, the processing production area stage, and the consumption area stage. At the landing production area stage, waste is generated from the primary processing at the production area and the pre-processing process of raw fish for processing, as well as small fish that were not listed and discarded fish with no market value. Processing waste generated at the processing production area stage is waste generated from fillets, paste, canned goods, etc., and the amount generated is extremely large. At the consumption area stage, fish waste is generated mainly by mass retailers, restaurants, school lunch facilities, hotels and inns, etc.

[0006] Fish skeletal muscles are attached to bones, skin, and other skeletal muscles, and perform functions such as moving the skeleton, such as the joints and spine, maintaining posture against gravity, producing energy through muscle contraction, and protecting the internal organs. Skeletal muscles are composed of muscle fibers and interstitium, which is connective tissue mainly made of hard proteins such as tendons and fibers. Examples of hard proteins include collagen and elastin.

[0007] For example, collagen is a protein that mainly constitutes the skin, fascia, ligaments, tendons, and bones of vertebrates, and is the main component of the extracellular matrix (ECM) of animals. The total amount of collagen present in the body is so large that it accounts for about one-third of the total protein in vertebrates such as fish.

[0008] The ability to completely separate these proteins from bones would be of great significance, as it would mean the development of edible protein sources, the solution to food waste, the reduction of methane gas from livestock farming, and the achievement of the SDGs.

[0009] The seafood processing industry has been researching and utilizing myosin, actin, and other components of fish muscle fibers, but these are only a part of the fish muscle protein, and fish also contain many other proteins.

[0010] Frozen surimi, a raw material for the manufacture of various fish paste products including kamaboko, was developed in 1960 by a research group led by Takasuke Nishitani at the Hokkaido Fisheries Experimental Station. The research group mixed sugars and polymerized phosphates with refined fish meat made by soaking and dehydrating Alaska pollock meat, and then froze the mixture to practically prevent the denaturation of fish meat proteins during freezing (see, for example, Non-Patent Document 4). This was a groundbreaking technology for the seafood processing industry, and currently, frozen surimi is used in almost all fish paste products. Frozen surimi is manufactured all over the world because it allows for mass processing and maintains fish prices, and "SURIMI" has become a global lingo. Currently, more than 800,000 tons of frozen surimi are produced annually in countries around the world, including the United States, China, Vietnam, India, and Thailand. This frozen surimi is made by freezing only refined fish meat, and has the advantages of convenient storage and transportation of raw materials before manufacturing various paste products, the advantage of being able to omit manual processes such as cooking the raw fish and soaking it in water, and the advantage of being able to steadily obtain and store raw materials of stable quality throughout the year. However, depending on the type of fish, the yield rate of surimi is poor at 25% to 40%, and a large amount of processing residue is generated during the production process of frozen surimi.

[0011] In the fish paste product industry, fish meat extracting machines that physically separate fish meat from bones and skin have been developed since the 1920s, and include stamp type, mesh drum type (roll type), and caterpillar type, all of which operate on the same principle (see, for example, Patent Document 1 and Patent Document 2). The fish is crushed on a mesh plate or drum with countless fine holes, and only the soft meat is pushed out through the holes and separated from the tough bones and skin. The fine fish meat extracted in this way is called "otoshimi."

[0012] For example, in a mesh drum type fish meat harvesting machine, as shown in Fig. 5, a mesh drum 502 with many holes is brought into contact with a rubber belt 503 and rotated in opposite directions. Fish 501 is crushed between the mesh drum 502 and the rubber belt 503, and only fish meat 504 is sent into the inside of the mesh drum 502.

[0013] Currently, such fish meat harvesting machines use fish dresses from which the heads and internal organs have been removed as the separating raw material, and even if these raw materials are pre-processed to extract the meat, a large amount of meat remains, resulting in a low yield. Although it depends on the fish species, the meat extraction yield of fish is generally said to be 60% to 80% for dresses and 25% to 40% for whole fish.

[0014] On the other hand, various efforts have been made to increase the yield of harvested meat, and a meat and bone separator that separates bones and meat by crushing and extruding has been developed (see, for example, Patent Document 3).

[0015] Furthermore, known prior art techniques for introducing enzymes into food ingredients include a method for producing food ingredients in which enzymes are introduced into the tissues of a plant-based food material to soften it while maintaining the original shape of the food material (see, for example, Patent Document 4), and a method for producing soft plant-based foods in which the salt concentration of a seasoning liquid is adjusted, frozen and thawed, and then immersed in an enzyme liquid and reduced pressure to introduce enzymes into the tissues, thereby producing soft plant-based foods that are seasoned and sterilized by pressurized heating without losing their shape (see, for example, Patent Document 5). [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Publication No. 49-072785 [Patent Document 2] Publication No. 50-089991 [Patent Document 3] Special Publication No. 2019-515647 [Patent Document 4] Patent No. 3686912 [Patent Document 5] JP 2006-223122 A [Non-patent literature]

[0017] [Non-Patent Document 1] Willett, W. et al, Food in the Anthropocene: the EAT-Lancet Commission on Healthy Diets from Sustainable Food Systems, Lancet 393, 447-492(2019) [Non-Patent Document 2] Golden, C. et al, Aquatic foods to nourish nations, Nature 598, 315-320 (2021) [Non-Patent Document 3] FAO: The State of World Fisheries and Aquaculture. 2020 [Non-Patent Document 4] Takasuke Nishitani et al.: Research on freezing and application of surimi (part 5) Manufacturing method of frozen surimi as a raw material for kneaded products. Monthly Bulletin of the Hokusui-Shi. 18(4), 14-27(1961) Summary of the Invention [Problem to be solved by the invention]

[0018] However, no fish meat harvesting machine can extract the aforementioned skeletal muscles such as tendons and tendons, or meat attached to fish skin or bones, making utilization of the harvested meat residue a major challenge.

[0019] For example, even when the conventional techniques for softening food described in Patent Documents 4 and 5 are used, how to extract muscle tissue from fish bones remains a major challenge.

[0020] Therefore, in order to solve such problems, an object of the present invention is to provide a method for producing animal-derived proteins that can efficiently produce fish protein that has been separated and harvested from bones. [Means for solving the problem]

[0021] The production method according to claim 1 of the present invention is a method for producing an animal-derived protein, comprising: an enzyme addition step of shredding a raw material consisting of at least one of fish and its processing residues, and adding an enzyme solution; and subjecting the raw material treated in the enzyme addition step to a vacuum pressure reduction; The above Moisture in the raw materials boiling Let The contents were in an expanded state. The method comprises a decompression step, in which a decompression / normal pressure operation is carried out at least once and then returned to normal pressure; an enzymatic decomposition step, in which the enzyme solution is left for a fixed period of time at the optimum temperature and optimum pH for the enzymatic reaction by the enzyme solution; an enzyme inactivation step, in which the temperature is raised to 90°C to 95°C and the enzymes in the enzyme solution are inactivated at high temperature; and a bone and meat separation step, in which, after the enzymes have been inactivated in the enzyme inactivation step, the raw material protein is separated and harvested from the bones using a bone and meat separation device. Effect of the Invention

[0022] According to the present invention, fish protein separated from bones can be efficiently produced. This allows energy saving and water saving in food production compared to traditional methods, and reduces the burden on the environment, while allowing muscle tissue of fish and other animals to be separated from bones with high work efficiency and without waste. In addition, the material separated from bone and meat can be used as a raw material for fish protein, fish peptides, fish oil, and fish bone calcium by further undergoing solid-liquid separation and oil-water separation processes, which is of great industrial significance in terms of utilizing underutilized fish and manufacturing and processing residues, reducing food waste, and creating a new source of edible protein. [Brief description of the drawings]

[0023] [Figure 1] 1 is a flow chart of a representative example of a meat and bone separation process of the present invention. [Figure 2A] 1 is a light microscope photograph showing yellowfin tuna meat immediately after freezing. [Figure 2B] 1 is a light microscope photograph showing yellowfin tuna flesh after 50 days of frozen storage at -18°C. [Figure 3A] 1 is an electron microscope photograph showing the tissue structure of flounder muscle fiber immediately before the decompression step. [Figure 3B] 1 is an electron microscope photograph showing the tissue structure of soleus muscle fibers immediately after the decompression step. [Figure 4A] 1 is an electron microscope photograph showing the cross-sectional structure of flounder muscle tissue immediately before the decompression step. [Figure 4B] 1 is an electron microscope photograph showing the cross-sectional structure of flounder muscle tissue immediately after a decompression process. [Diagram 5] FIG. 1 is a diagram for explaining a conventional technique for physically separating fish meat from bones and skin using a mesh drum type fish meat harvester. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the present invention, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the present invention.

[0025] In order to solve the above-mentioned problems of the conventional technology, the present invention aims to provide a method for efficiently producing fish protein separated from bones by carrying out a treatment having a high effect of separating meat and bones.

[0026] In order to achieve the above object, the inventors have conducted extensive research and have come up with the following technical method. The principle of this method is that it consists of four steps: (1) slow freezing, (2) vacuum decompression, (3) simultaneous internal and external enzyme decomposition, and (4) meat and bone separation.

[0027] In the basic procedure of the specific operation, first, a slow freezing operation is performed in which raw materials consisting of at least one of raw or heat-denatured fish and its processing residues are frozen through a slow freezing temperature range of about -7°C to -20°C (freezing step). After that, the frozen raw materials are cut into small pieces, and an enzyme solution is added and thawed while stirring (enzyme addition step). If possible, the thawed raw materials are heated to a predetermined temperature (the optimum temperature for the enzyme reaction by the added enzyme solution) in order to reduce the load on the vacuum pump in the subsequent vacuum decompression operation. This stirring may be performed during the vacuum decompression operation described later. This heating may also be performed during the vacuum decompression operation described later or during the simultaneous internal and external decomposition operation of the enzyme.

[0028] Next, with the enzyme solution added, a vacuum pump is used to reduce the pressure. After that, the contents are expanded and the pressure is returned to normal. This process of reducing and then increasing the pressure to normal can be repeated once or several times as necessary, and then the pressure is returned to normal (pressure reduction step).

[0029] Next, an internal and external simultaneous decomposition operation of enzymes that advance the enzymatic reaction at a specified temperature is carried out (enzymatic decomposition process). Once the desired degree of decomposition is reached, the temperature is raised and the enzymes in the treated material are inactivated by heat treatment or the like (enzyme inactivation process). By inactivating the enzymes by heat, the decomposition stops and unwanted bacteria are killed. Furthermore, collagen from fish skin, connective tissue, etc. that cannot be completely decomposed is thermally denatured and becomes gelatin, making it easier to collect. The enzyme compounding, each procedure, and temperature control must be changed depending on the raw materials and equipment used.

[0030] The meat is then sent to a meat and bone separator, where it is subjected to a meat and bone separation process (meat and bone separation step), and then the product is manufactured through the subsequent dehydration and purification steps. When the amount of raw material is small, the meat and bone may be separated using a strainer or sieve instead of the meat and bone separator.

[0031] A representative example of the bone and meat separation process including the above four operations will be described below with reference to the flow chart in FIG. 1. The slow freezing operation included in the representative example shown in FIG. 1 is not an essential operation in the present invention, as described in Example 4 below. That is, the raw material may be chopped into small pieces while still raw, and then an enzyme solution may be added and stirred, followed by a vacuum decompression operation. However, it is more preferable to add this operation, since the loosening of the tissue caused by the slow freezing operation can increase the muscle tissue destruction and enzyme introduction speed due to the volume expansion and contraction in the decompression process. In addition, a pressurization operation can be performed instead of the vacuum decompression operation, but the vacuum decompression operation is preferable in that it can efficiently introduce the enzyme into the inside of the fish meat. These operations allow the enzyme to penetrate every corner of the tissue, eliminating the time difference between the enzyme reaction on the surface and inside of the fish meat. Furthermore, in the flow chart in FIG. 1, heating is performed before the "(2) vacuum decompression operation" to reduce the load on the vacuum machine, but the "(2) vacuum decompression operation" may be performed before heating.

[0032] First, steps S101 and S102 are carried out for the slow freezing operation. First, in step S101, the raw fish is slowly frozen. This causes ice crystals to form and grow inside the raw fish, loosening the bonds of the muscle tissue inside the raw fish. Then, proceeding to step S102, the raw fish after slow freezing is chopped and thawed to obtain chopped material.

[0033] Next, steps S103 to S105 are performed for the vacuum decompression operation and the simultaneous internal and external decomposition operation of the enzyme. First, in step S103, an enzyme liquid is added to the shredded material obtained in step S102. By cutting the raw material, the surface area increases, the thawing speed increases, and the enzyme liquid to be added can easily penetrate into the raw material. Next, proceeding to step S104, the shredded material after the enzyme liquid is added is placed in a vacuum decompression device, and the shredded material is repeatedly subjected to reduced pressure and normal pressure at a predetermined temperature. During the decompression in step S104, the moisture inside the muscle in the shredded material vaporizes (boils) and expands, and when the pressure returns to normal, the vaporized moisture liquefies and contracts. In the process of repeated expansion and contraction, the muscle tissue inside the shredded material is destroyed by a force that physically stretches it. Furthermore, when the pressure returns to normal and the material contracts, the enzyme liquid that was added to the shredded material in advance in step S103 replaces the moisture in the tissue inside the shredded material, filling the voids in the muscle tissue and penetrating every corner. The predetermined temperature here is a temperature set according to the properties of the added enzyme, and is a temperature at which the enzyme that has permeated the muscle tissue in step S104 has the activity to decompose hard proteins such as collagen at the bone-meat junction or myofibrillar proteins both inside and outside the muscle tissue. After that, in step S105, the shredded material to which the enzyme solution has been added after the process in step S104 is heated to a high temperature to inactivate the added enzyme.

[0034] Finally, step S106 is executed for the meat and bone separation operation. In step S106, the meat and bone are separated by the meat and bone separator, and the process ends.

[0035] As described above, in the present invention, muscle tissue of fish and the like is efficiently separated and harvested from bones by the bone meat separation process shown in FIG. 1, and animal-derived protein is produced.

[0036] Each of steps S101 to S106 will be described in detail below.

[0037] (Step S101: Slow freezing of raw fish) This process involves freezing and storing the raw fish at -7°C to -20°C. There are no particular limitations on the raw fish, but single fish species such as small sardines, anchovies, horse mackerel, mackerel, and blue whiting, as well as underutilized and under-utilized small fish and exterminated fish can be used. In addition, fish ilium and meat residues produced by surimi processing, end meat, backbone, and head fins produced by canning, filleting, and sashimi processing can also be used, and even fish that have been freezer burned due to long-term excessive refrigeration or fish that have been denatured by heating can be used as raw materials.

[0038] When water freezes, the water molecules align through hydrogen bonds and become crystalline. The volume becomes 1.1 times that of the liquid state. The slow freezing and thawing process causes ice crystals to form and grow inside the cells and muscle tissue of the raw material, expanding the volume and destroying the cells and muscle tissue. In other words, during the slow freezing and thawing process, the ice crystals grow and become larger, and when they reach a state commonly known as "porosity," the cells and muscle tissue in the raw material are destroyed and their bonds with the bone become loose.

[0039] Normally, the size and number of ice crystals that form during freezing depend on the temperature at which they crystallize. In other words, the speed at which ice crystal seeds form (ice nucleation rate) and the speed at which these seeds grow (crystal growth rate) depend on the temperature at which ice crystals begin to form within the food. When ice crystals form at low temperatures, many ice nuclei form, but because their growth rate is slow, the ice crystals become small. On the other hand, when ice crystals form at high temperatures, only a few ice nuclei form and because their growth rate is fast, the ice crystals become large.

[0040] During frozen storage, when the environmental temperature rises, some of the ice crystals melt. At that time, the relatively small ice crystals disappear and become liquid water, but the larger ice crystals remain. When the temperature drops again, the remaining ice crystals grow according to phase equilibrium. If this melting and crystal growth is repeated, the small ice crystals gradually disappear and the larger ice crystals grow larger and larger. This slow freezing process utilizes these principles to destroy muscle tissue using the force of ice crystal growth during frozen storage.

[0041] Figures 2A and 2B show optical microscope photographs of yellowfin tuna meat taken at 200x magnification. Figure 2A shows yellowfin tuna meat immediately after freezing, and Figure 2B shows yellowfin tuna meat after 50 days of frozen storage at -18°C. These photographs were taken at 200x magnification using a BX50 system optical microscope (Olympus Corporation). It can be seen that as storage time increases, ice crystals grow larger, loosening the muscle tissue and creating a state of so-called "porosity."

[0042] (Step S102: Shredding and defrosting) This process is a process of appropriately cutting the frozen or raw materials taken out of the freezer. By cutting the materials, the surface area increases, the thawing speed increases, and the enzyme solution added in step S103 can easily penetrate into the materials. Here, a frozen cutter is used, but a silent cutter or frozen cutting machine can also be used. A vacuum cutter with both cutting and vacuum decompression functions is even better.

[0043] (Step S103: Adding enzyme solution) This step is a step of adding an enzyme solution to the raw material (shredded material) cut into small pieces in step S102. The shredded raw material is added to a reduced pressure digestion tank (or as is in the case of a vacuum cutter), and a protein-degrading enzyme (protease) solution of a predetermined concentration or fruit pulp juice is added and stirred. Here, actinidin, a type of protease, is used, but other plant enzyme preparations such as papain, bromelain, ficin, and ginger protease, animal enzyme preparations such as pepsin, trypsin, and chymotrypsin, and microbial protein-degrading enzyme preparations such as sumizyme, or plants such as kiwi fruit, maitake mushroom, papaya, and pineapple, or extracts thereof, may be used alone or in combination. The amount of enzyme preparation used is 0.01% by weight to 1.0% by weight, preferably 0.03% by weight to 0.5% by weight, more preferably 0.05% by weight to 0.10% by weight, and the amount of pulp juice used is 0.5% by weight to 10.0% by weight, preferably 1.0% by weight to 5.0% by weight, more preferably 1.5% by weight to 3.0% by weight. After adjusting the pH to the optimum reaction pH range of the enzyme, for example, pH 6.5, with sodium bicarbonate or acetic acid, in order to reduce the load on the vacuum pump in the next step, the mixture is heated to a predetermined temperature (the optimum temperature for the enzyme reaction by the enzyme solution). For example, the mixture is heated to 30°C to 75°C, preferably 40°C to 65°C, more preferably 45°C to 60°C. However, the timing of this heating may be during the subsequent vacuum decompression operation or during the simultaneous internal and external decomposition operation of the enzyme.

[0044] (Step S104: Repeatedly subjecting the shredded material to reduced and normal pressure) This process consists of a decompression process and an enzymatic decomposition process. In the decompression process, the shredded material is subjected to a vacuum decompression and then returned to normal pressure, and this decompression and normal pressure operation is carried out at least once. The inside of the fish meat and the joints of the bones and meat expand due to the evaporation of water by the vacuum decompression, and then the pressure is returned to normal pressure, causing the inside of the fish meat and the joints of the bones and meat to shrink. This repeated process of expansion and contraction stretches and destroys the muscle tissue. In the decompression process, when the shredded material is returned to normal pressure from the decompressed state, the enzyme solution added in advance replaces the water in the tissue, and the enzyme solution fills the voids in the muscle tissue of the shredded material, penetrating every corner. In the enzymatic decomposition process, the raw material is placed under optimal temperature and pH conditions for the enzyme reaction by the enzyme solution in this state, and the muscle tissue is decomposed both inside and outside at the same time.

[0045] (Decompression process) In the decompression process, the vacuum cutter after the enzyme is added or the vacuum pump of the heated raw material decomposition tank is operated, and the water in the raw material is evaporated and the contents expand. The decompressed state is maintained for 10 seconds at the point where the muscle tissue is destroyed by the force of this expansion. The raw material is then returned to normal pressure. If necessary, this decompression and normal pressure operation is repeated once or several times in the decompression process. This allows the enzyme solution added in advance to penetrate all the voids in the raw material tissue at once when the shredded material is returned to normal pressure.

[0046] According to the vapor pressure curve of water, the boiling point of water is 101.325 kPa at 100°C, 19.865 kPa at 60°C, 0.611 kPa at 0°C, and 0.107 kPa at -20°C. When vaporizing the water in the shredded muscle tissue in the decompression process, the vacuum requirement is less severe at higher temperatures than at lower temperatures, and the load on the vacuum pump is lighter. For example, at 60°C, which is the optimal temperature for the enzyme reaction using a plant-based protein-degrading enzyme solution, water vaporizes when the pressure drops below about 19.865 kPa. Therefore, it is desirable to carry out the decompression process at a specified temperature (the optimal temperature for the enzyme reaction using the enzyme solution).

[0047] When moisture in muscle tissue evaporates by reducing the pressure of raw materials at a specified temperature, Boyle's law states that the volume of gas V is proportional to the absolute temperature T and inversely proportional to the pressure P. If the number of moles of gas is n and the gas constant is R, the gas equation of state PV=nRT holds true. For example, if the specified temperature is 60°C: 19.865kPa x V = 1mol x 8.31 x (273 + 60), so V = 139.3L. 1mol of water is 18g = 0.018L, so the volume of water expands by 139.3 / 0.018 = 7739 times. In other words, when the pressure is reduced at 60°C, the volume of water expands by more than 7000 times. By similar calculations, the volume of water expands by more than 12000 times at 50°C and more than 19000 times at 40°C. This repeated expansion and contraction further physically tears and destroys the muscle tissue that was loosened during slow freezing, making it easier for the enzyme solution to penetrate during contraction and also making the bone and meat separation process easier.

[0048] Figure 3A is an electron microscope photograph showing the structure of the flounder muscle fiber tissue immediately before the decompression process, and Figure 3B is an electron microscope photograph showing the structure of the flounder muscle fiber tissue immediately after the decompression process. These electron microscope photographs were taken using a JSM-5600LV scanning electron microscope (JEOL Ltd.) in low vacuum mode at 15 kV and 250x magnification. It can be seen that after the volume expansion due to water evaporation caused by the decompression, the muscle fiber tissue is shredded and destroyed.

[0049] Figure 4A is an electron microscope photograph showing the cross-sectional structure of flounder muscle tissue just before the decompression process, and Figure 4B is an electron microscope photograph showing the cross-sectional structure of flounder muscle tissue just after the decompression process. These electron microscope photographs were taken using a JSM-5600LV scanning electron microscope (JEOL Ltd.) in low vacuum mode at 15 kV and 250x magnification. It can be seen that after the volume expansion due to water evaporation caused by decompression, the cross-section of the muscle fibers is torn and destroyed.

[0050] (enzyme decomposition process) In the enzymatic decomposition step, after the decompression step, the raw material is returned to normal pressure and kept at the predetermined temperature in a raw material decomposition device such as a heating kneader, a heating kettle, or a Joule heater for a certain period of time, specifically 10 to 120 minutes, preferably 15 to 60 minutes, and more preferably 20 to 40 minutes, to carry out the enzymatic decomposition and cleavage reaction of connective tissues and muscle proteins. The certain period of time may be any period of time required to reach a predetermined target decomposition degree.

[0051] (Step S105: Enzyme inactivation) In this process, the raw material decomposition tank after the enzymatic decomposition process is heated with stirring and left at 90°C to 95°C for 60 minutes to inactivate the enzymes in the enzyme solution. During this process, some of the collagen that is not completely decomposed is softened by gelatinization, reducing its breaking strength and making it easier to collect.

[0052] (Step S106: Separation of meat and bone) This step is a bone and meat separation step in which bones are removed from the raw material after enzymatic decomposition. Here, a bone and meat separator was used, but various meat extractors, strainers, refiners, sieve-type presses, etc. may also be used.

[0053] The principles and embodiments of the present invention will be described below with reference to examples. However, the following examples are merely for explaining the method of the present invention and its core idea, and those skilled in the art can modify the specific embodiments and application scope based on the idea of ​​the present invention. Therefore, the contents of this specification do not limit the present invention.

[0054] Example 1 The meat residues (bones, skin, fins, tendons, etc.) from the production of raw surimi of white croaker (Pennahia argentata) were frozen in a -18℃ freezer for one month, then shipped out and chopped with a food cutter. After that, 3% green kiwi fruit juice was added to the raw material, the pH was adjusted to 6.5, and the mixture was mixed and packed into a heat-resistant and pressure-resistant bag, and the pressure was reduced using a tabletop vacuum packaging machine. When the contents expanded, the vacuum was stopped, the reduced pressure was maintained for 10 seconds, the pressure was returned to normal, and the pressure was reduced again, and the heat-resistant and pressure-resistant bag containing the raw material was sealed. The sealed heat-resistant and pressure-resistant bag was placed in a constant temperature water bath at 60℃, and the enzyme decomposition reaction was carried out while maintaining the temperature at 60℃. After 20 minutes, the temperature was raised and the mixture was left at 90℃ for 60 minutes to inactivate the enzymes in the enzyme solution. The bones and muscle tissue decomposition products were then separated using a sieve and used for the next product manufacturing process.

[0055] Example 2 The filleted backbone of farmed Basa fish (Pangasius bocourti) was frozen in a -18℃ freezer for six months, then removed from the freezer and put into a vacuum Stephan cutter to cut it into pieces. 5% green kiwi fruit pulp was added to the raw material, the pH was adjusted to 6.3, and the vacuum pump was turned on while stirring to reduce the pressure. When the contents expanded, the vacuum was stopped, the reduced pressure was maintained for 10 seconds, and the pressure was returned to normal. The raw material was then loaded into a tabletop Joule heating tofu manufacturing device, heated by electrical current, and enzyme decomposition reaction was carried out while maintaining the temperature at 60℃. After 20 minutes, the temperature was raised and the mixture was left at 95℃ for 60 minutes to inactivate the enzymes in the enzyme solution. The bones and muscle tissue decomposition products were then separated by straining through a sieve and used for the next product manufacturing process.

[0056] Example 3 A block (55 x 37 x 5 cm) of frozen Japanese anchovy (Engraulis japonica) is frozen in a -18°C freezer for 12 months, then removed from the freezer and placed in a vacuum bowl cutter. The raw material is then chopped into small pieces using the vacuum bowl cutter, and a papain solution is added to the vacuum bowl cutter so that the final concentration is 0.05%, and sodium bicarbonate solution is used to adjust the pH to 7.0. The vacuum pump is then started, and the raw material expands due to the evaporation of moisture inside. When the contents become expanded, the vacuum is stopped, the reduced pressure is maintained for 10 seconds, and a reduced pressure / normal pressure operation is performed to return the pressure to normal. The same reduced pressure / normal pressure operation is performed again. The raw materials were then removed, placed in a heating kneader and heated to 60°C, where the enzymatic decomposition reaction was carried out. After 20 minutes, the temperature was raised and the mixture was left at 95°C for 60 minutes to inactivate the enzymes in the enzyme solution. The bone and muscle tissue decomposition products were then separated using a sieve and used in the next product manufacturing process.

[0057] Example 4 The meat residues (bones, skin, fins, tendons, etc.) from the production of Alaska pollock (English name: Alaska pollock; scientific name: Gadus chalcogrammus) paste are obtained by cooling on ice, put into a silent cutter while raw, cut into pieces, and then transferred to a vacuum decompression decomposition tank, where actinidin solution is added to a final concentration of 0.1%, heated while stirring, and adjusted to pH 6.5 using sodium bicarbonate solution and acetic acid. When the temperature reaches 60°C, heating is stopped. After that, the vacuum pump is operated while maintaining the temperature at 60°C, and the raw material expands due to the evaporation of moisture inside at around 18kPa. When the contents become expanded, the vacuum is stopped, and the reduced pressure state is maintained for 10 seconds, followed by a reduced pressure / normal pressure operation to return to normal pressure. The same reduced pressure and normal pressure operations were repeated once more, after which the enzymatic hydrolysis reaction was carried out while maintaining the temperature at 60°C. After 20 minutes, the temperature was raised and the solution was left at 90°C for 60 minutes to inactivate the enzymes in the enzyme solution. The bone and muscle tissue hydrolysates were then separated using a bone and meat separator and used in the next product manufacturing process.

[0058] Example 5 The head, scales, backbone, fins, etc. left over from the fillet production of Pacific cod (Gadus macrocephalus) are placed in a freezer and frozen in a -18℃ freezer for six months, then removed from the freezer and put into a vacuum bowl cutter. While chopping, bromelain solution is added to a final concentration of 0.1%, and the pH is adjusted to 6.5 using sodium bicarbonate and acetic acid. After that, the vacuum pump is started and the raw material expands due to the evaporation of the moisture inside. When the contents become expanded, the vacuum is stopped, the reduced pressure is maintained for 10 seconds, and a reduced pressure / normal pressure operation is performed to return to normal pressure. After the same reduced pressure / normal pressure is performed again, the raw material is removed and put into a continuous Joule heating line, where an enzymatic decomposition reaction is carried out while maintaining the temperature at 60℃ by electrical heating. After keeping it warm for 20 minutes, the temperature is raised and it is left at 95℃ for 60 minutes to inactivate the enzymes in the enzyme solution. After that, the bones and muscle tissue decomposition products are separated by a strainer and used for the next product manufacturing process.

[0059] Example 6 Frozen products such as backbone, skin, and fins left over from the production of sashimi of Yellowfin tuna (Thunnus albacares) are frozen in a -18℃ freezer for six months, then removed from the freezer, put into a frozen cutter, and chopped into small pieces. The products are then transferred to a vacuum decompression tank, where actinidin solution is added to a final concentration of 0.1%, heated while stirring, and adjusted to pH 6.5 using sodium bicarbonate and acetic acid. When the temperature reaches 60℃, heating is stopped. After that, while maintaining the temperature at 60℃, the vacuum pump is operated, and the raw materials expand at around 18kPa due to the evaporation of moisture inside. When the contents become expanded, the vacuum is stopped, and the reduced pressure state is maintained for 10 seconds, followed by a reduced pressure / normal pressure operation to return to normal pressure. The same reduced pressure and normal pressure operations were repeated once more, after which the enzymatic hydrolysis reaction was carried out while maintaining the temperature at 60°C. After 20 minutes, the temperature was raised and the solution was left at 90°C for 60 minutes to inactivate the enzymes in the enzyme solution. The bone and muscle tissue hydrolysates were then separated using a bone and meat separator and used in the next product manufacturing process.

[0060] Example 7 After washing the exterminated black bass (Micropterus), they are arranged in a freezer pan and frozen in a -18℃ freezer for one month, then taken out and put into a frozen cutter to chop them into pieces, then transferred to a vacuum decompression decomposition tank, where green kiwi fruit extract is added to a final concentration of 1%, heated while stirring, and adjusted to pH 6.5 using sodium bicarbonate and acetic acid. When the temperature reaches 60℃, heating is stopped. After that, while maintaining the temperature at 60℃, the vacuum pump is operated, and the raw material expands at around 18kPa due to the evaporation of moisture inside. When the contents become expanded, the vacuum is stopped, and the reduced pressure state is maintained for 10 seconds, followed by a reduced pressure / normal pressure operation to return to normal pressure. After repeating the same reduced pressure and normal pressure operation once more, the enzymatic hydrolysis reaction was carried out while maintaining the temperature at 60°C. After 20 minutes, the temperature was raised and the solution was left at 90°C for 60 minutes to inactivate the enzymes in the enzyme solution. After that, the bone and muscle tissue hydrolysates were separated using a bone and meat separator and then used in the next product manufacturing process.

[0061] Example 8 A frozen block of Japanese barracuda (Sphyraena japonica) that had been left in a freezer for 3 years and 4 months and whose proteins had denatured due to freezer burn, making it unsuitable as a normal edible ingredient, was taken out, put into a frozen cutter and chopped, then transferred to a vacuum decompression tank, where minced maitake mushrooms were added to a final concentration of 2%, heated while stirring, and adjusted to pH 7.0 using sodium bicarbonate solution. When the temperature reached 55°C, heating was stopped. After that, while maintaining the temperature at 55°C, the vacuum pump was operated, and the ingredients expanded at around 14kPa due to the evaporation of moisture inside. When the contents became expanded, the vacuum was stopped, and the reduced pressure state was maintained for 10 seconds, followed by a reduced pressure / normal pressure operation to return to normal pressure. The same reduced pressure and normal pressure operations were repeated once more, after which the enzymatic hydrolysis reaction was carried out while maintaining the temperature at 55°C. After 30 minutes, the temperature was raised and the solution was left at 90°C for 60 minutes to inactivate the enzymes in the enzyme solution. The bone and muscle tissue hydrolysates were then separated using a bone and meat separator and used in the next product manufacturing process.

[0062] Example 9 The small fish of the sea bream are put into a frozen pan and stored in a freezer at -20℃ for three months, then put into a frozen cutter and chopped into pieces, then transferred to a vacuum decompression decomposition tank, actinidin solution is added to a final concentration of 0.1%, heated while stirring, and adjusted to pH 6.5 using sodium bicarbonate solution and acetic acid. When the temperature reaches 60℃, the heating is stopped. After that, while maintaining the temperature at 60℃, the vacuum pump is operated, and the raw material expands due to the evaporation of moisture inside at around 18kPa. When the contents become expanded, the vacuum is stopped, and the reduced pressure is maintained for 10 seconds, and then a reduced pressure / normal pressure operation is performed to return to normal pressure. After performing the same reduced pressure / normal pressure operation once again, the enzyme decomposition reaction is performed while maintaining the temperature at 60℃, and after 20 minutes, the temperature is raised and the enzyme in the enzyme solution is inactivated by leaving it at 90℃ for 60 minutes. Then, the bone and muscle tissue decomposition products are separated by a sieve and subjected to the next product manufacturing process.

Claims

1. A method for producing an animal-derived protein, comprising the steps of: An enzyme addition step of shredding a raw material consisting of at least one of fish and its processing residues and adding an enzyme liquid; a depressurization step in which the raw material treated in the enzyme addition step is vacuum-depressurized, the water in the raw material is boiled, and the raw material is expanded, and then the pressure is returned to normal pressure; an enzymatic decomposition step of leaving the enzyme solution at an optimal temperature and optimal pH for a certain period of time; an enzyme inactivation step of inactivating the enzyme in the enzyme solution at a high temperature of 90°C to 95°C; The method for producing the present invention further comprises a bone and meat separation step of separating and harvesting the raw material protein from the bones using a bone and meat separator after the enzyme is inactivated in the enzyme inactivation step.

2. The method further comprises a freezing step of slowly freezing the raw material, 2. The method according to claim 1, wherein the raw material is chopped in the enzyme addition step while the raw material is in a frozen state, and the enzyme is added after the raw material is thawed.

3. 3. The method according to claim 2, wherein in the freezing step, the raw material is subjected to a slow freezing temperature range of -7°C to -20°C.

4. The method according to any one of claims 1 to 3, characterized in that the enzyme solution contains an enzyme preparation, and an enzyme consisting of a pulp juice and an extract thereof, either singly or in combination, of at least one of Maitake mushroom, kiwi fruit, papaya, and pineapple, the amount of the enzyme preparation used being 0.01% by weight to 1.0% by weight, and the amount of the pulp juice used being 0.5% by weight to 10.0% by weight, relative to the raw material, and the pH is adjusted to an optimal reaction pH range for the enzyme with sodium bicarbonate or acetic acid.

5. The method according to claim 4, characterized in that the amount of the enzyme preparation used is 0.03% by weight to 0.5% by weight relative to the raw material.

6. The method for producing a fermentation product according to claim 5, characterized in that the amount of the enzyme preparation used is 0.05% by weight to 0.10% by weight relative to the raw material.

7. The method according to claim 4, characterized in that the amount of the pulp juice used is 1.0% by weight to 5.0% by weight relative to the raw material.

8. The method according to claim 7, characterized in that the amount of the pulp juice used is 1.5% by weight to 3.0% by weight relative to the raw material.

9. 5. The method according to claim 4, wherein the enzyme preparation comprises at least one of a plant-derived enzyme preparation, an animal-derived enzyme preparation, and a protease preparation derived from a microorganism.

10. The method according to claim 9, characterized in that the plant-based enzyme preparation comprises at least one of actinidin, papain, bromelain, ficin, and ginger protease.

11. The method according to claim 9, characterized in that the animal enzyme preparation comprises at least one of pepsin, trypsin, and chymotrypsin.

12. The method according to claim 9, characterized in that the protease preparation derived from a microbial system is Sumizyme.

13. 2. The method according to claim 1, wherein the decompression and normal pressure operation in the decompression step is carried out after the raw material is heated to the optimum temperature.

14. The manufacturing method according to claim 1, characterized in that after the enzyme is added to the chopped raw material in the enzyme addition step, the raw material is vacuum-decompressed while being stirred in the decompression step, and the raw material is heated to the optimal temperature in the enzymatic decomposition step.

15. 2. The method according to claim 1, wherein the optimum temperature is between 30°C and 75°C.

16. The manufacturing method described in Claim 15, characterized in that the optimal temperature is 40°C to 65°C.

17. The manufacturing method described in Claim 16, characterized in that the optimal temperature is 45°C to 60°C.

18. 2. The method according to claim 1, wherein in the bone and meat separation step, the raw material protein can be separated and collected from the bones using a sieve.

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