JP2017085932A - Fish processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fish processing method which can maintain freshness easily for a long time by a method using a linear tool.SOLUTION: In an immediate killing step S2 of a processing method S10 of the present invention, a punch hole 12 penetrates a brain 22 and a medulla oblongata 22a to communicate with a neural arch 26 of a first abdominal vertebra 24a. At this point, an instruction system from a brain 22 of fish 10 is destroyed to restrict a movement of the fish, thus allowing reducing consumption of ATP in a fish body to the minimum. A linear tool 52 used for breaking nerve can be easily inserted into the neural arch 26 through the punch hole 12, thus allowing easy nerve-breaking process.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a processing method for maintaining the freshness of fish by so-called nerve squeezing, specifically, delaying the arrival of post-mortem stiffness. In the present specification, “narrowing” means to destroy and remove the spinal cord, and “bleeding” means to release blood in the body of the fish.

  It is known that the fish body changes roughly in four stages after the fish dies. First, immediately after death, the fish is in the same state as when it is alive. Thereafter, the body of the fish becomes stiff due to post-mortem rigidity, and then the body of the fish is loosened by unraveling the post-mortem rigidity. Eventually, the fish will rot.

  The reason why fish body is stiff after death is that adenosine triphosphate (ATP), which is an energy source of life activity, is decomposed into amino acids by degrading enzymes in the body. It is thought that the structure of myofibrils is weakened by degrading enzymes (proteases). The arrival of these decomposition reactions has been found to be much faster for fish compared to cattle, pigs and chickens.

  In order to maintain the freshness of fish, the arrival of ATP degradation reaction, that is, the arrival of post-mortem stiffness, the state where the fish body is biochemically active, that is, the state where ATP is present in the muscle It is required to maintain. Conventionally, in order to delay the arrival of fish stiffness after death, a method of damaging or destroying / removing the spinal cord passing through the nerve arch of the fish spine has been employed. This process suppresses spinal nerve runaway (nervous runaway) and suppresses the consumption of ATP in muscles due to muscle spasms resulting from nerve runaway that occurs after the death of the fish. For example, Patent Documents 1 to 5 disclose such techniques.

JP-A-7-264968 JP 11-318268 A JP 11-318324 A JP 2009-261351 A JP2013-94165A

  In Patent Document 1, the fish brain is pierced with a blade and destroyed, a knife is inserted from the heel, the spinal cord, the aorta, and the vena cava are cut, the spine near the caudal fin is cut, and the neural arch from the caudal fin side A method of ejecting fluid into the portal and removing the spinal cord, medulla and brain, or a method of sucking the spinal cord, medulla and brain from the caudal nerve arch with a vacuum pump or the like is disclosed. .

  Patent Document 2 discloses a method of losing only the motor function without dying the fish by inserting a piercing tool from the heel and damaging the spinal cord.

  Patent Document 3 discloses a method in which only the motor function is lost by cutting the spinal cord while keeping the fish respiratory function normal.

  Patent Document 4 discloses a linear tool that is inserted into the nerve arch to destroy and remove the spinal cord. Also, a method of providing a linear auxiliary hole with a depth of 1 to 2 cm on the head side of the fish, inserting a linear tool into the spine to destroy and remove the spinal cord, and then cutting the heel to drain the blood. Is also disclosed.

  Patent Document 5 discloses a method in which a tube provided with a bent portion is inserted from the orbit of a fish to reach the nerve arch to secure the insertion path of the linear tool into the spinal cord.

  However, the method disclosed in Patent Document 1 has the following problems. That is, when fluid is ejected from the caudal side into the nerve arch, the fluid and spinal cord are clogged at any of the nerve arches toward the brain, causing the spine to expand, and in the worst case, the spine and fish may burst. There is. In addition, both when jetting fluid into the nerve arch and when sucking the brain and spinal cord from the nerve arch, a dedicated device is required for that purpose, and many processing steps are required, which is troublesome. . Moreover, since it is necessary to cut | disconnect the spine of the part near a caudal fin, the intensity | strength of the part becomes weak. Therefore, for example, when holding the tail fin and lowering the fish to three, there is a disadvantage that it is difficult to cook the fish.

  Since the methods disclosed in Patent Documents 2 and 3 require skilled techniques, it is difficult to acquire the techniques, and even if the processing is successful, fish in a living state are not carried in water. Therefore, there is a problem that transportation is difficult. In addition, there is a problem in that if the treatment is inadequate and the fish dies, the spinal nerve runaway is inevitable and the freshness decreases. In addition, when a fish is cut as in Patent Document 3, especially in overseas markets, the cut surface is misunderstood as a scratch, but the meat quality near the cut surface is reduced due to moisture absorbed from the cut surface. However, there is a possibility that the value of the product may be lowered, for example, the number of parts that cannot be used as sashimi increases and the yield decreases.

  On the other hand, Patent Document 4 is a device in which the linear tool itself is devised, and according to the method disclosed in the document, the spinal cord of a fish can be easily compared with the methods disclosed in Patent Documents 1 to 3. It can be destroyed and removed. However, it has not led to drastic process improvement from the viewpoint of fish physiology necessary for maintaining long-term freshness and improving meat quality, and there is still room for improvement. Moreover, although it is disclosed that an auxiliary hole is provided on the fish head side, the auxiliary hole only functions as an inlet for inserting the linear tool into the fish body. Fish may go wild and consume ATP.

  Further, in the method of Patent Document 5, there is a problem that when the tube provided with the bent portion is inserted from the eye socket of the fish, the fish is likely to be exposed and ATP is easily consumed.If the processing fails, the eyeball pops out. There is a possibility of deteriorating the product value.

  Therefore, in view of the above-mentioned problems of the prior art, the present invention is a method using a linear tool, which is simpler, and further enables processing of fish that can maintain long-term freshness by a processing technique based on a fish physiological viewpoint. The aim is to provide a method and ultimately improve the value of fresh fish in overseas and Japanese markets.

The present invention relates to a fish processing method comprising an immediate killing process for destroying a fish brain, a nerve tightening process for destroying the spinal cord by inserting a linear tool into the nerve arch of the fish, and a blood draining process for bleeding.
The instant killing step is performed by providing a perforation that penetrates the fish brain and medulla and communicates with the nerve arch of the first abdomen.
The above-mentioned problem has been solved by a fish processing method, wherein the nerve tightening step is performed by inserting the linear tool through the perforation into the nerve arch.

  According to the present invention, since the perforation is provided so as to penetrate the brain and the medulla, the command system from the fish brain is destroyed at that time, and the movement of the fish is suppressed. Furthermore, since the perforation is provided so as to communicate with the nerve arch of the first abdomen, the linear tool can be easily inserted into the nerve arch. Therefore, it is possible to produce a fish that has been squeezed by a simpler method than in the past.

  Moreover, it is good to perform blood bleeding by cut | disconnecting the abdominal aorta or back aorta of a fish. When blood is drained by cutting the spine near the heel and caudal fins in a general way, blood appears to be released, but the blood pressure in the body drops rapidly, Blood remains in the capillaries. On the other hand, since the autonomic nervous system heart moves even if the fish is in a brain dead state by providing a perforation, the blood can be discharged by pumping blood through the heart by cutting the abdominal or dorsal aorta. As a result, blood can be removed from the capillary blood in a short time and efficiently.

  Also in the present invention, blood removal is usually performed after the nerve tightening step. However, depending on the fish, it is preferred that blood removal be performed prior to the instant kill process. This is because the meat quality can be improved.

  Moreover, it is good to pass through the pre-cooling process which maintains the body temperature to the temperature of 5 degreeC or more and lower than natural water temperature after performing blood removal and after stiffening starts after fish death. By this treatment, the collapse of the membrane structure of the sarcoplasmic reticulum in the muscle cell can be delayed, and the release of calcium ions, which cause the onset of postmortem stiffening, into the muscle cell can be delayed. This is similar to the phenomenon called cold shortening in livestock meat, which prevents the promotion of calcium ion release at low temperatures, thereby making it possible to delay the arrival of fish stiffness after the death of fish that have undergone the normal nerve tightening process. The freshness can be maintained for a long time. According to the inventor's knowledge, it has been confirmed that blue fish such as mackerel, which is said to arrive early after death, can delay the arrival of post-mortem stiffness for about 2 to 5 hours.

  In addition, after the pre-cooling step, when the fish has become rigid after death, it is preferable to go through a post-mortem cooling step that maintains the body temperature of the fish at 0 ° C. or higher and 5 ° C. or lower. Thereby, the rise of K value which is a parameter | index of freshness can be suppressed, and the freshness of a fish can be maintained for a long period of time.

  Moreover, it is good to pass through the overhanging process which puts a fish in the water of natural water temperature before providing perforation. Thereby, since the content of ATP in the fish body can be recovered, it is possible to further delay the arrival of post-mortem stiffening of the fish after nerve tightening treatment, and to maintain the freshness of the fish for a longer period.

The figure showing the flow of the 1st processing method of this invention. The partial perspective view which showed the position of each organ in the fish which belongs to a perch. The figure which showed the quick kill process of this invention in the fish 10 of FIG. Sectional drawing of the vertebral body of the fish 10 of FIG. The figure which showed the nerve tightening process of this invention in the fish 10 of FIG. The figure which shows the example of the position of the drilling | piercing of this invention in the fish which belongs to the flatfish. The figure which showed the nerve tightening process of this invention in the fish 100 of FIG. The figure showing the flow of the 2nd processing method of this invention.

  An embodiment of the present invention will be described with reference to FIGS. However, the present invention is not limited to this embodiment.

  The fishes to be processed by the processing method of the present invention are most fishes having a vertebra, for example, blue fish such as sardines, horse mackerel, mackerel, yellowtail, amberjack, hiramasa, Thai, flatfish, flatfish, grouper White fish such as sea bream, scorpionfish and barracuda, and red fish such as bonito and tuna. The present invention can also be applied to freshwater fish.

  FIG. 1 shows the overall flow of the first fish processing method S10 of the present invention. In the processing method S10, after the survival process S1, the immediate kill process S2 is followed by the nerve tightening process S3, the blood removal process S4, the pre-cooling process S5, and the post-mortem cooling process S6.

  Below, each process of processing method S10 is demonstrated. The survival process S1 is performed by storing the fish to be processed in water at a natural water temperature for several hours to overnight. Here, the “natural water temperature” refers to the water temperature of the sea, river, or the like that is the growth environment of fish, or a water temperature that is slightly lower (about 2 ° C.). In addition, as long as the state of the fish can be calmed, the fish may be put in a ginger provided in the sea or the like, or may be put in a water tank.

  By passing through the survival process S1, the state of the fish can be calmed down and the ATP content in the body can be recovered. Restoring the ATP content in the fish body is important in maintaining the freshness of the fish. This is because the fish that rampaged just before landing consumes ATP in the body, and even if the nerve squeezing process is performed, the content of ATP in the body is low, so that the arrival of rigidity after death is accelerated. That is, in order to delay the arrival of stiffness after death, the content of ATP in the body is restored.

  After calming down the fish in the survival process S1, the process proceeds to the immediate kill process S2. Here, first, each organ of the nervous system of fish will be described. The fish 10 shown in FIG. 2 is a fish belonging to the perch, and other fish basically have the same configuration. 2, 3 and 5, illustration of bones such as the ribs 32 (see FIG. 4) is omitted for convenience. A brain 22 is housed in a skull (not shown) of the fish 10 and has a spine 20 formed by connecting a plurality of thrusters 24. Of the thrusters 24, the one closest to the brain 22 is referred to as a “first abdominal vertebra” (reference numeral 24a). A spinal cord 27 passes through the nerve arch of the spine 20 (see FIG. 4), and the brain 22 and the spinal cord 27 are connected. There is a medulla oblonga 22 a between the brain 22 and the spinal cord 27.

  In the quick kill process S2, as shown in FIG. 3, immediately after the fish in the water is taken out, the perforations 12 are provided using the piercing tool 50. The piercing tool 50 is preferably a needle-like one such as an ice pick. The perforation 12 is provided so as to penetrate the brain 22 and the medulla 22a of the fish 10 and communicate with the nerve arch 26 (see FIG. 4) of the first abdominal vertebra 24a. How to provide the perforation 12 for the fish differs depending on the fish, but if the position of the nerve arch of the fish brain, medulla oblongata and first abdomen is grasped by dissecting the fish beforehand, Good.

  Here, since the perforations 12 are provided so as to penetrate the brain 22 and the medulla oblongata 22a, the command system from the brain 22 of the fish 10 is destroyed at this point. Thereby, since the movement of the fish 10 is suppressed instantaneously, the operation of the nerve narrowing step S3 described later can be easily performed in a state where consumption of ATP in the fish body is minimized. In the present invention, since only the small perforations 12 remain on the appearance of the fish 10, scars are hardly conspicuous, and it is possible to prevent a decrease in the commercial value of the fish. Moreover, since it is not necessary to cut the spine side or the head side spine, the strength of the caudal part can be maintained, and the meat quality near the cut surface is reduced due to moisture absorbed from the cut surface. Things can also be prevented.

  In the case of the fish 10 or a fish having a skeleton similar thereto, the perforation 12 may be provided by piercing the piercing tool 50 from the center position of both eyes of the fish, but the piercing tool from a position slightly approaching either eye. 50 should be provided. The center position of both eyes of the fish 10 has a hard skull and it is difficult to pierce the piercing tool 50. From the position slightly approaching one of the eyes, the piercing tool 50 is relatively easy to pierce and the immediate kill process S2 is performed. This is because it can be easily performed. Moreover, since the perforation 12 is not conspicuous when the fish 10 is used for appearance, the commercial value can be improved.

  Next, the nerve tightening step S3 will be described. As shown in FIG. 4, the vertebral body 24 of the fish 10 includes a rib 32, and further, a nerve arch 26 through which the spinal cord 27 passes and a blood arch 36 through which the dorsal artery 34 passes are formed. Above the nerve arch 26 is a nerve spine 28. As described above, the spine 20 (see FIG. 2) of the fish 10 is formed by connecting a plurality of vertebral bodies 24, and thus the nerve arch 26 and the hemodynamic arch 36 are formed over the entire spine 20. .

  In the present invention, the fish 10 is already provided with the perforations 12 communicating with the nerve arch 1 of the first abdominal vertebra 24a by the immediate killing step S2. Therefore, as shown in FIG. 5, if the linear tool 52 is inserted along the perforation 12, the linear tool 52 can be easily guided to the nerve arch 26. The linear tool 52 is inserted into the nerve arch 26 and moved back and forth over the entire spine 20 to destroy and remove the spinal cord 27 of the fish 10. The linear tool 52 is a wire-like instrument made of elastic metal or resin, and has a diameter corresponding to the thickness of the spinal cord depending on the fish species so that the spinal cord can be reliably destroyed and removed. . As described above, according to the present invention, since the linear tool 52 is easily inserted into the nerve arch 26 and no special tool is required, the nerve tightening step S3 can be easily performed.

  By the way, the vertebral bodies constituting the fish spine are usually smaller from the head toward the tail, and the nerve arch is also narrowed accordingly. For this reason, when a linear instrument is inserted by cutting the spine on the caudal side, only a thin linear instrument can be inserted, so that the spinal cord in the nerve arch of the spine on the head side tends to remain. On the other hand, according to the configuration in which the linear instrument 52 is inserted from the first abdominal vertebra 24a of the fish 10 as in the present invention, the thick linear instrument 52 can also be inserted. It can be prevented from remaining inside.

  Next, the blood removal step S4 of the present invention will be described. In the processing method S10, the blood removal step S4 is performed after the nerve tightening step S3 and before the pre-cooling step S5 described later. Here, the vascular system of the fish 10 will be described. As shown in FIG. 2, the fish 10 has a heart 30. Although not shown in detail, blood sent from the heart 30 returns to the heart 30 through the abdominal aorta 31, the dorsal aorta 33, and the dorsal artery 34 passing through the blood arch 36 of the vertebral body 24.

  Blood removal may be performed by inserting a blade between the lid 42 and the lid 44 and cutting the abdominal aorta 31 or the dorsal aorta 33 or both. By passing through the immediate killing step S2, the fish 10 is in a brain dead state and the command system from the brain 22 is destroyed, but since the heart 30 of the autonomic nervous system is moving, the abdominal aorta 31 or the dorsal aorta 33 or This is because by cutting both of them, blood can be discharged by pumping blood through the heart 30. As a result, blood can be removed from the capillary blood in a short time and efficiently.

  As described above, in the processing method S10, the life support function of the fish is cut off through the immediate killing step S2, the nerve tightening step S3, and the blood removal step S4, so that it is not necessary to transport the fish in water. Therefore, the transportation cost can be reduced as compared with the case where the fish is transported alive.

  Next, the precooling step S5 will be described. The pre-cooling step S5 is a step of lowering the body temperature of the fish that has undergone the nerve narrowing step S3 and the blood draining step S4 to a state that is 5 ° C. or higher and lower than the natural water temperature, and maintains the fish body temperature until the post-mortem stiffness starts. Specifically, although it varies depending on the type and size of fish, habitat, season, etc., the body temperature is 5 ° C. or more and lower than the natural water temperature by putting the fish in 5-15 ° C. water or in a refrigerator for a certain period of time. This is done by lowering the temperature and maintaining that state. For example, a precooling time of about 15 to 30 minutes is set for a fish weighing about 1 kg. In addition, when the fish is saltwater fish and put in water, it is preferable to use ice and water, and use seawater as the water. Thereby, since the osmotic pressure difference with the fish body can be reduced and the absorption of moisture into the fish body can be suppressed, the meat quality can be maintained in a good state. In addition, precooling process S5 can also be performed while transporting a fish.

  It is said to be “cold shortening”, when the body temperature drops below 5 ° C. before the start of stiffness after the death of the fish, the membrane structure of the sarcoplasmic reticulum collapses, calcium ions are released in a short time, and the arrival of stiffness after death is accelerated. A phenomenon occurs. On the other hand, if the body temperature of the fish is higher than about 7 ° C., the digestion rate of ATP increases and the arrival of stiffness after death may be accelerated, and the growth rate of bacteria also increases, which is a problem in freshness management. In addition, when the fish is cooled in seawater, if the water temperature is 10 ° C. or higher, Vibrio parahaemolyticus that is a resident bacterium in the seawater also grows, so care must be taken when setting the precooling water temperature.

  Even after the pre-cooling step S5, it is practically impossible to avoid the stiffness of fish after death. However, it is possible to suppress the decomposition rate of ATP in the fish body by appropriately controlling the temperature according to the state of the fish body. The temperature management for this is the post-hardening cooling step S6. The freshness of fish is generally represented by a freshness index K value, and the lower the K value, the better the freshness. After the death of fish, the K value increases with time, but after the arrival of post-mortem stiffness, the K value is decreased by cooling the fish so that the body temperature of the fish is maintained at 0 ° C. or more and 5 ° C. or less in the cooling step S6 immediately after the death. Can be suppressed, and the freshness of the fish can be maintained for a longer period of time. Note that the post-mortem cooling step S6 can also be performed while the fish is being transported.

  The present invention can also be applied to flounder fish as shown in FIG. Since the basic procedure is the same as described above, detailed description is omitted, but in the quick kill process, as shown in the figure, a straight stab tool (not shown) such as an ice pick is used to A perforation 112 may be provided so as to penetrate the brain 122 and the medulla 122a and communicate with the nerve arch of the first abdominal vertebra 124a. Then, as shown in FIG. 7, the linear tool 52 is inserted along the perforation 112, further inserted into the nerve arch (not shown), and moved forward and backward over the entire spine 120, so that the fish 100 The spinal cord 127 is destroyed and removed. Conventionally, when squeezing the fish of a flounder fish, it has been common to cut the tail or head and insert a linear tool into the nerve arch. However, according to the present invention, even in the case of flounder fish, the linear tool 52 can be easily inserted into the nerve arch by simply providing the perforation 112 as shown in FIG. It can be processed as a beautiful fish.

  Next, the second processing method S20 of the present invention will be described with reference to FIG. Since the specific content of each process is the same as that of processing method S10, the description is abbreviate | omitted. In the processing method S20, the order of the blood removal step S4 is different from the processing method S10, and the blood removal step S4 is performed after the survival step S1 and before the immediate killing step S2. By performing the blood removal step S4 before the immediate killing step S2 as in the processing method S20, the meat quality can be improved depending on the type of fish. For example, the cultured red sea bream that has undergone the blood removal step S4 in the processing method S20 has a tendency to fade in color immediately after being killed, but as the body matures through rigor after death, the transparency of the color increases and blood It has been found by the inventor that it can be used as sashimi with little raw odor. This is because the blood in the fish body is almost completely released in the blood removal step S4 in the processing method S20, so that after the death of the fish, deterioration of the body due to breeding of germs in the blood and the raw odor peculiar to the blood of the fish can be suppressed. Conceivable. In the case of the cultured red sea bream of the above example, freshness and texture can be maintained for one day or longer for sashimi use, compared to other cultured red sea bream that has been subjected to nerve squeezing.

  As described above, according to the present invention, it is possible to provide a method for processing fish that is simple and can maintain freshness for a long period of time.

S10, S20 Fish processing method S1 Live-over process S2 Immediate kill process S3 Narrowing process S4 Blood removal process S5 Pre-cooling process S6 Post-hardening cooling process 10, 100 Fish 12, 112 Perforation 22, 122 Brain 22a, 122a Medullary 24a, 124a First abdominal vertebra 26 Nerve arch 27, 127 Spinal cord 31 Abdominal aorta 33 Back aorta 52 Linear tool

Claims (7)

In a fish processing method having an immediate killing process for destroying the fish brain, a nerve tightening process for inserting a linear tool into the nerve arch of the fish to destroy the spinal cord, and a blood draining process for blood removal,
The instant killing step is performed by providing a perforation that penetrates the fish brain and medulla and communicates with the nerve arch of the first abdomen.
The nerve tightening step is performed by inserting the linear tool from the perforation into the nerve arch.
Fish processing method.   The fish processing method according to claim 1, wherein the blood removal step is performed by cutting the abdominal or dorsal aorta of the fish.   The fish processing method according to claim 1 or 2, wherein the blood removal step is performed after the nerve tightening step.   The method for processing fish according to claim 1 or 2, wherein the blood removal step is performed before the instant killing step.   The fish processing method according to any one of claims 1 to 4, further comprising a precooling step of maintaining the body temperature of the fish at 5 ° C or higher and lower than a natural water temperature after the blood removal step until the fish starts to stiff after death. .   6. The method for processing fish according to claim 5, further comprising a post-hardening cooling step for maintaining the body temperature of the fish at 0 ° C. or higher and 5 ° C. or lower when the fish has become rigid after the pre-cooling step.   The method for processing a fish according to any one of claims 1 to 6, further comprising a survival step of placing the fish in water at a natural water temperature before the instant killing step.

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