JP3605759B2 - Pressure treatment method before killing fish immediately - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
Fresh fish, which is said to be lively, is fresh after death, as if it were alive. It often refers to fish that are stiff or stiff after death. Therefore, maintaining the freshness of fresh fish extends the "period to complete rigidity after immediate killing". Recently, the live fish are immediately killed and stored at a temperature of 5 to 15 ° C. higher than 0 ° C., thereby extending the “period until complete rigidity” to maintain freshness.
The present invention relates to a pressurizing treatment method for pre-immediate killing of fish which enables the freshness of such lively-finished live fish to be maintained.
[0002]
[Prior art]
Conventionally, the technique for maintaining the freshness of live fish has been ice storage, but recently, a technique of distributing at the ice temperature or the aforementioned temperature of 5 to 15 ° C. has been developed. In addition, although the transport of live fish requires about 10 times as much water as the fish, a technique using needle anesthesia that requires only 20 to 30% of the amount of water has recently been developed.
[0003]
[Problems to be solved by the invention]
In recent years, the trend of high-quality fish and high-freshness fish has been increasing, and the current situation is that live fish and live fish are traded at high prices in the consumer market. Due to the high cost of using live fish transport vessels and vehicles, and the fact that live fish are closed up to meet the demand of consumers up to large consuming areas far from the landing area, the high price may be due to early morning work. In addition, labor costs will increase.
In addition, frozen transport becomes thawed fish when thawed, and loses its value as a fresh fish in the market. As a technique for maintaining freshness, a technique using needle anesthesia has become widespread in recent years, but it cannot be processed in large quantities, and there is a limit in a place where a small amount of water is required.
In addition, live fish transport is not only available at live fish restaurants, but can be delivered to ordinary households, and from a local production area, a form of transportation that enables high-purity fish to find inexpensive and safe fresh fish is desired. ing.
[0004]
The present invention provides a pressurizing method for fish immediately before killing , which facilitates supply of consumers with high freshness to consumers, which enables reduction of distribution costs and air transportation (air transportation) in transporting live and fresh fish. The purpose is to provide .
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention according to claim 1 provides a method in which fish are charged into a pressurized tank containing fresh water or seawater and air is pumped, and fine air bubbles are formed in fresh water or seawater. It is characterized in that it is generated in seawater and supplied with air, and after a predetermined time, the inside of the pressurized tank is slowly degassed to discharge fishes and to perform live tightening.
[0006]
The invention according to claim 2 is that, in a pressurized tank containing fresh water or seawater, while feeding fish and pumping air, fine air bubbles are generated in freshwater or seawater to supply air, After a predetermined period of time, the inside of the pressurized tank is rapidly degassed to discharge fishes and perform vibrating.
According to the present invention, the fish at the time of excretion are paralyzed by decompression sickness, and their movements are dull.
[0007]
The invention according to claim 3 is that, in a pressurized tank filled with fresh water or seawater, fish are fed and air is pumped, and fine air bubbles are generated in freshwater or seawater to supply air; After a predetermined time, the inside of the pressurized tank is quickly degassed to discharge fish, and the fish are transported while being utilized in an adaptive environment. The fish are discharged slowly and then transferred to a fish cage or live-filled.
According to the present invention, since almost no water is required for transportation, air transportation is also possible. Then, in the pressurization process again, fine air bubbles are similarly generated to give air (oxygen) to the fish body .
[0008]
According to a fourth aspect of the present invention, in any one of the first to third aspects, freshwater or seawater is heated.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the method for instantaneously killing and pressurizing fish according to the present invention will be described with reference to the accompanying drawings.
First, in order to pressurize fish, it is necessary to have a pressurized tank for putting fish together with freshwater or seawater (hereinafter referred to as seawater). The optimal pressure to pressurize fish is 3 atm for eel and 2 atm for tilapia. Since the air is pressurized, an air compressor having a low-pressure variable output is prepared. Further, by injecting air, pressure is applied to the air and seawater in the pressurized tank, and the amount of dissolved oxygen in the seawater increases, so that no particular oxygen gas is required and the apparatus is simplified.
[0010]
In order to increase the amount of dissolved oxygen in water in the closed pressurized tank, as a first means, air in a pressurized air layer in the pressurized tank is sucked, and fine bubbles placed in the bottom of the tank are sucked. there is a method of circulating water in the tank is ejected from the generator (aerator) as fine bubbles.
As a second means, there is a method in which air discharged from an air compressor is directly sent to a fine bubble generator in order to increase the amount of dissolved oxygen in water in a tank. In this case, the pressurized tank is temporarily raised to the set pressure by the air compressor, and then the piping is switched to slightly increase the set pressure and sent to the fine bubble generator. The air is automatically released and the pressure is maintained.
Further, as another setting condition, there is an adaptation temperature at the time of the pressurization processing according to the fish body. Therefore, a hot water circulation device is added to the pressurized tank and used appropriately.
[0011]
From the above, the pressurizing tank 1 of the pressurizing apparatus shown in FIG. 1 which can carry out the method for instantly killing and pressurizing fish of the present invention has a cylindrical shape, and the cylindrical axis is in the vertical direction (horizontal direction). But it is good). The seawater input pump 2 is connected to the pressurized tank 1 by a seawater input pipe 3, and a nozzle 4 at the tip of the seawater input pipe 3 is located above a set water level, and seawater is injected from the nozzle 4 into the pressurized tank 1. . The seawater inlet pipe 3 is provided with a valve (a check valve) 5. A drain nozzle 6 and a valve 7 are provided at the bottom of the pressurized tank 1.
[0012]
An air compressor 8 for putting air into the pressurized tank 1 is provided with a valve 10 and a pressure setting gauge 11 on a pipe 9, and a nozzle 12 of the pipe 9 faces a pressurized air layer above a set water level of the pressurized tank 1. It is provided in. A pressure reducing valve 13 and an automatic pressure adjusting valve (pressure adjusting device: a device having a valve for releasing excess pressure in order to maintain a set pressure) 14 are provided on the upper surface of the pressurized tank 1.
Suction side of the air circulation pump 15 is provided in an upper portion facing the pressurized air layer configuration above water surface of the pressure tank 1, the discharge side is plumbed to a height of more than the set water once, pressurized plumbed downwardly therefrom It is connected to a fine bubble generator 16 arranged at the bottom of the pressure tank 1 . Thereby, seawater does not enter the air circulation pump 15 when seawater is supplied.
[0013]
The hatch 17 for inputting fish is disposed above the pressurized tank 1 and the hatch 18 for discharging fish is disposed on the side of the pressurized tank 1 from which fish can be easily discharged. Size that can accommodate humans.
[0014]
A dissolved oxygen meter 19 for measuring the amount of dissolved oxygen in the pressurized tank 1 is installed at a position where the average value of the water in the pressurized tank 1 can be obtained.
A window 20 is appropriately provided in the pressurized tank 1 to visually check the inside of the pressurized tank 1 during the pressurizing process. A water level gauge is not required when the window 20 is also used for checking the amount of injected water, but a water level sensor is installed when the supply of seawater is automatically stopped.
[0015]
The hot water circulation device 21 includes a heating device (for example, a boiler) 22 and a circulation pump 23, and a suction side pipe is connected to an upper layer of seawater in the pressurized tank 1 and connected to the heating device 22 side of the hot water circulation device 21. Then, the circulation pump 23 side of the hot water circulation device 21 is connected to the lower part of the seawater of the pressurized tank 1 by the discharge side pipe, and the nozzle 24 of the discharge side pipe is arranged along the inner wall of the pressurized tank 1 (tank tangential direction). Toward). A thermometer 25 is provided near the dissolved oxygen meter 19.
When the hot water is circulated, the pressure water supplied by the circulation pump 23 is jetted from the nozzle 24, circulates horizontally in the pressurized tank 1, and is pumped with a stirring effect so as to eliminate the water temperature difference in the pressurized tank 1. Will be done. If there is an obstacle to the direct entry of seawater into the heater 22, the heater may be heated via a heat exchanger.
[0016]
Next, the operation of pressurizing the fish body will be described.
Since the pressurized tank 1 takes out the fish body after the pressurizing process from the discharge hatch 18 on the side surface, the pressurized tank 1 is installed higher than the floor by a support stand to facilitate the work.
First, the fish discharge hatch 18 provided in the pressurized tank 1 is closed, the valve 7 of the drain nozzle 6 is closed, the seawater input pump 2 is operated to supply seawater to a specified water level, and the fish input hatch 17 is closed. Open and put an appropriate number of fish in the pressurized tank 1. This state can be confirmed by viewing the set water surface from the window 20 provided on the side surface of the pressurized tank 1.
[0017]
Next, the input hatch 17 is closed, the air compressor 8 is operated, and air is fed into the pressurized tank 1 by pressure. When the pressure inside the pressurized tank 1 becomes equal to or higher than the set pressure, the automatic pressure regulating valve 14 operates. It is maintained at the set pressure. As the set pressure, an appropriate pressure (2 to 5 atm) is selected according to the type of fish body, and the pressurizing time is maintained. If necessary for supplying oxygen, the air compression device 8 and the automatic pressure regulating valve 14 may be always operated or may be intermittent.
[0018]
On the other hand, the air circulation pump 15 is operated after the pressure reaches the set pressure, sucks the air in the upper part of the pressurized tank 1, and blows out fine bubbles from the fine bubble generator 16 so as not to give stress to the fish. The bubbles rise in the water and promote the circulation of water, and because the seawater is pressurized, the dissolved oxygen in the water increases, and the amount of dissolved oxygen in the seawater increases almost in proportion to the pressure (Henry's law ).
Here, based on the data read from the dissolved oxygen meter 19, the pressurization value and the degree of generation of fine bubbles are adjusted so as to be under appropriate conditions.
[0019]
Here, since the hot water circulation device 21 is operated depending on the fish, the valves 26, 27, and 28 of this pipe are opened from the beginning, and when the water level reaches the set water level, the circulation pump 23 is operated to inject hot water from the nozzle 24. It will also serve as stirring of seawater.
[0020]
As described above, by increasing the pressure in the pressurized tank 1 to 2 to 5 atm, a dissolved oxygen water having a concentration 1.5 to 4.0 times higher than usual is generated. In the high-concentration dissolved oxygen water in the pressurized tank 1, the respiratory control function of fish is paralyzed for 26 hours or more. During this time, the fish retain oxygen in the muscle cells. For example, the optimal pressure for applying pressure to the fish body is about 3 atm for eel and about 2 atm for tilapia, so that a large amount of pressurization can be performed safely. The pressurizing time is set between about 30 minutes and 3 hours.
[0021]
Next, the method of the present invention for pressurizing fish immediately before killing, particularly the process after pressurizing fish is described.
Explaining with reference to the method 1 of FIGS. 1 and 3, after the pressurization process is completed , the pressure reducing valve 13 is opened and the slow deaeration requires about 10 minutes (about 10 to 15 minutes) (see the method 1 of FIG. 3). Then, the inside of the pressurized tank 1 is returned to the atmospheric pressure, and the treated fish is discharged and taken out from the discharge side hatch 18 together with the seawater, received in a container so that the fish is not damaged, and a live-closing operation is performed on the spot. The fish that have been vigorously processed are transported in a cold storage state. A process for returning the inside of the pressurized tank 1 to the atmospheric pressure by rapid deaeration requiring about one minute (about 30 to 90 seconds) will be described later.
Since the inside of the pressurized tank 1 is cleaned by increasing the size of the discharge side hatch 18, a cleaning member can easily enter from here.
[0022]
When the fish is taken out of the pressurized tank 1 and immediately killed (vigorized), the supply of oxygen is cut off, the production cycle of ATP (adenosine triphosphate), which is the energy source of the fish, is stopped, and stiffness occurs after death. Oxygen is present in postmortem fish muscle, maintaining the production cycle and delaying postmortem stiffness. It should be noted that IMP (inosinic acid) resulting from the decomposition of ATP is regarded as an important umami component, and the umami taste is doubled in the pressurized fish body because a large amount of ATP is generated as described later.
[0023]
Hereinafter, examples in which fish subjected to pressure treatment are killed immediately will be described for horse mackerel and eel.
The fish bodies of the horse mackerel and eel which were subjected to the pressure treatment were immediately stored at 5 ° C. immediately after the killing. Time) about 1.5 times. In addition, the initial ATP content of both fish species subjected to pressure treatment after immediate killing increased about 1.5 times as compared with the untreated group.
[0024]
In this case, it is possible to prevent softening of the meat quality by slow degassing, maintain a lump feeling when eating, and maintain high freshness for the purpose of utilizing raw food for sashimi such as horse mackerel.
In the case of eel, the IMP content reached the maximum 24 hours later, 6 hours behind the untreated group. Further, unlike the non-treated group, the pH and lactic acid of the treated group subjected to the pressurization treatment showed almost no change from immediately after killing to storage for 30 hours.
From these results, it is inferred that the whole tissue of the fish subjected to the pressure treatment maintained an aerobic state for a while after death.
[0025]
Next, the quality when the eel subjected to the pressure treatment is burnt white will be described.
The white baked was divided into the white baked fish which had been subjected to the pressure treatment (rapidly degassed) and baked immediately. The three types of “slices” that were white-baked after storage at 5 ° C. for 24 hours are compared with respect to three points of “meat swelling”, “appearance (appearance shape)”, and “eating”.
The white baking in the untreated section was all worse than in the control section, and was judged to be low in commercial value. On the other hand, in the white baked in the treated group, even when stored, the appearance of white baked and the swelling of the meat were equivalent to those in the control group, and the taste was higher than that in the control group. It is considered that the enhancement of the umami is due to an increase in the amount of IMP produced due to an increase in ATP due to the pressure treatment. It has been clarified that the present invention is effective for maintaining high freshness and umami of live fish.
[0026]
As another pressurizing method before killing other fish, referring to Method 2 in FIGS. 1 and 3, the pressurizing tank 1 is rapidly degassed within 1 minute after the pressurizing process. After returning to the atmospheric pressure, the treated fish is discharged from the discharge side hatch 18 together with fresh water or seawater, taken out, received in a container without damaging the fish, and a live-closing operation is performed on the spot. The fish that have been vigorously processed are transported in a low-temperature storage condition that is equal to or higher than the ice temperature.
In this vignetting process, the freshness can be kept longer than the conventional one, and the taste can be increased. In addition, it is suitable for fish for cooking and processing where soft meat such as eel is preferred, and can reproduce the melting feeling, which is one of the textures when white-baked. Furthermore, when eels are broken, the storage time until white-burning is extended, and the work force can be dispersed.
[0027]
Further, another method for pressurizing fish immediately before killing will be described with reference to method 3 in FIG.
When the pressurization processing is performed by the above-described pressurization processing apparatus of FIG. 1 and the inside of the pressurization tank is rapidly evacuated, the state of oxygen anesthesia during the pressurization processing changes to a state of decompression sickness, and the movement of the fish becomes dull. The fish in this state are further placed in ice water and their activity is reduced by a temperature shock. Then, the fish is wrapped in moistened newspaper or the like so that the surface does not dry, and the fish is transported.
Raw fish that can be transported in the production area are loaded onto a refrigerated truck without using a conventional water tank and transported to the consumption area.
[0028]
The transported fish is again put into the pressurized tank of the pressurized processing device at the consuming area and subjected to pressurized processing. At this time, the same type of pressure processing device may be used, or another type of pressure processing device described later may be used. In this case, the type of the pressure processing apparatus is selected according to the installation conditions at the consuming area.
After pressurizing the fish, the inside of the pressurized tank is slowly degassed. The transported fish are returned to live fish. By performing vignetting in this state, fishes contain oxygen more than usual. Therefore, it is good for fishes that are desired to have freshness, umami, and lumpiness as live fish and fresh fish, and can meet the demands of consumers. On the other hand, it can be transferred to a fish cage and used for live cultivation as appropriate.
In this transport, for example, tilapia can survive twice as long as it is untreated (about 3 hours), and flounder can survive about 2-3 times longer than it does without treatment (about 3 hours). . Accordingly, the transportation equipment and transportation time can be spared, and the transportation cost is reduced to about 1/10 when transported by truck or the like. Unlike conventional live fish transport and needle anesthesia, almost no water is required, so air transport (air transport) is also possible.
[0029]
Next, another pressure processing apparatus that can carry out the pressure processing method for immediately killing fish according to the present invention will be described with reference to FIG.
The pressure treatment device shown in FIG. 2 is different from the pressure treatment device described above in that the fine bubble generator 16 produces fine bubbles that do not give stress to fish without using the air circulation pump 15 shown in FIG. That is, a valve 10 and a pressure setting gauge 11 are attached to the discharge side pipe 9 of the air compression device 8, and are connected to a fine bubble generator 16 installed at the bottom in the pressurized tank 1.
[0030]
The pressure processing apparatus of FIG. 2 feeds fish and freshwater or seawater, closes the charging hatch 17, and then operates the air compression device 8 to pump air into the pressure tank 1. At this time, since the pipe 9 is connected to the fine bubble generator 16, the sent compressed air becomes fine bubbles and rises in the water in the pressurized tank 1 to promote circulation of the water in the pressurized tank 1. The inside of the pressurizing tank 1 is pressurized.
When the pressure inside the pressurized tank 1 becomes equal to or higher than the set pressure, the automatic pressure adjusting valve 14 operates and is maintained at the set pressure. As the set pressure, an appropriate pressure (2 to 5 atm) is selected according to the type of fish body, and the pressurizing time is maintained.
[0031]
On the other hand, fine bubbles must always be generated from the fine bubble generator 16, and in order to maintain the set pressure while sending fresh air even after the inside of the pressurized tank 1 reaches the set pressure, the fine bubble generator Fresh air is supplied to the pressurized tank 16 at a pressure slightly higher than the set pressure of the internal pressure of the pressurized tank 1, and excess air is released outside by the automatic pressure control valve 14 while generating fine bubbles. Therefore, the air circulation pump 15 shown in FIG. 1 is omitted, and the apparatus is simpler.
Description Since pressure treatment of fish does not change as performed by pressure treatment apparatus of FIG. 1 described above will be omitted. Further, the method of pressurizing the fish body immediately before killing is the same as that performed by the pressurizing apparatus shown in FIG.
[0032]
【The invention's effect】
The method for pressurizing fish immediately before killing according to the present invention is as described above. According to the first aspect of the present invention , after pressurizing fish, the inside of the pressurized tank is slowly degassed. By vigorously closing the fish discharged from the pressurized tank, the time to reach full rigidity is delayed, transportation to the consuming area is facilitated, and freshness and umami can be maintained compared to conventional vignetting. Further, since the meat is prevented from being softened, the processing of live fish is effective for maintaining high freshness for the purpose of using raw food.
According to the second aspect of the present invention , after the fish is pressurized, the inside of the pressurized tank is rapidly degassed. When the discharged fish are vigorously used, the time required to reach full rigidity is delayed, but the meat is tenderized, and is suitable for cooking and processing fish where soft meat such as eel is preferred.
According to the third aspect of the present invention , the above-mentioned pressurizing treatment and rapid degassing simplify the transportation mode of fish, and after pressurizing and slow degassing again in the consuming area, vigorously tighten in the consuming area. It is suitable for fish whose cost is reduced and the freshness, umami, and savory taste are preferred in the consuming area as a live fish.
According to the fourth aspect of the present invention , for some fish whose higher water temperature is more suitable for inhabiting, the water temperature is raised, so that the pressure treatment can be performed in a more suitable environment without causing the fish to feel stress.
[0033]
Furthermore, according to the method for processing fish immediately before killing according to the present invention , live fish is put into a pressurized tank having an increased oxygen concentration, and then subjected to pressurizing treatment in an environment where fine bubbles are generated, followed by immediate killing (live closing). In this case, since oxygen is accumulated in the fish body, the decomposition time of ATP is prolonged, the time to reach full rigidity is remarkably increased, and high-quality fresh fish that has been vibrated can be maintained at high freshness. In addition, the freshness holding period can be extended to several stages (about 1.5 times or more) as compared with the conventional technique for keeping fresh fish fresh.
Furthermore, if home delivery is possible, high-quality fresh fish can be eaten not only in live fish restaurants but also in ordinary homes. Because there is no chemical treatment, it is a technology for maintaining freshness that is safe even when cooking at home.
According to the treatment of the present invention, the initial content of ATP is increased, the decomposition time is lengthened by that amount, and high freshness can be maintained. In addition, IMP increases during storage due to the increase in the initial content of ATP, and umami is enhanced. For example, fish whose consumption is concentrated at one time, such as eel, can reduce the labor shortage of laborers and disperse the labor force, and the yield of white-baked products can be maintained and economic effects can be expected.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a pressure processing apparatus that can carry out a pressure processing method for immediately killing fish according to the present invention.
FIG. 2 is a configuration diagram of another pressure processing apparatus capable of performing the pressure processing method for immediately killing fish according to the present invention.
FIG. 3 is a table illustrating three steps of a process of pressurizing fish according to the present invention.
[Explanation of symbols]
1 pressurized tank 3 seawater inlet pipe 6 outlet 8 air compressor
14 Automatic pressure regulating valve
15 Air circulation pump 16 Fine bubble generator 17 Hatch for charging 18 Hatch for discharging 19 Dissolved oxygen meter 20 Window 21 Hot water circulation device 22 Heating device 24 Nozzle

Claims (4)

Into the pressurized tank containing fresh water or seawater, fish are fed and air is pumped, and fine air bubbles are generated in freshwater or seawater to supply air, and after a predetermined time, the inside of the pressurized tank is slowed down A method for pressurizing fish immediately before killing, wherein the fish are degassed and the fish are discharged and vigorously tightened. Fish is put into a pressurized tank filled with freshwater or seawater, and air is pumped.At the same time, fine air bubbles are generated in freshwater or seawater to supply air, and after a predetermined time, the inside of the pressurized tank is rapidly increased. A method for pressurizing fish immediately before killing, wherein the fish are degassed and the fish are discharged and vigorously tightened. Fish is put into a pressurized tank filled with freshwater or seawater, and air is pumped.At the same time, fine air bubbles are generated in freshwater or seawater to supply air, and after a predetermined time, the inside of the pressurized tank is rapidly increased. Degas and discharge the fish, transport the fish while utilizing them in an adaptive environment, pressurize again at the destination using a pressurized tank, and after a predetermined time, slowly deaerate the pressurized tank and discharge the fish And a method of pressurizing fish immediately before being killed, wherein the fish is transferred to a fish cage or vigorously tightened. 4. The method for pressurizing fish immediately before killing according to claim 1, wherein fresh water or seawater is heated.

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