Production method of fish frozen product

Abstract

To provide a production method of a fish frozen product, capable of securely obtaining a fish frozen product having excellent freshness (low K value).SOLUTION: A production method of a fish frozen product includes: an immediately killing and extracting blood step of immediately killing ocean-fresh fish and extracting blood therefrom; a shape-forming step of shape-forming the fish immediately killed and subjected to blood extraction into a loin; a vacuum packaging step of vacuum-packaging the loin obtained by shape-forming; a calcium chloride liquid freezing step of charging a vacuum package of the vacuum packaged loin into a tank of a calcium chloride liquid at -35°C or less followed by freezing; a calcium chloride liquid removing step of removing a calcium chloride liquid adhering to a surface of the vacuum package taken out from the tank of the calcium chloride liquid; and a box-packaging step of box-packaging the vacuum package from which the calcium chloride liquid is removed. Specifically, a time from the start of the shape-forming step to the start of the calcium chloride liquid freezing step in each loin is controlled to within 10 minutes so as to manage a K value of the loin to be 5.0 or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing frozen fish products by shaping live fish and producing frozen products.

Background Art

[0002] As a method for instantaneously freezing fish to produce frozen products, Patent Document 1 discloses a freezing method in which, during freezing with calcium chloride brine, at a relatively high product temperature, the fish is once lifted out of the brine and left for a certain period of time at a temperature higher than the brine temperature and lower than the freezing point of the fish, and then immersed again in the brine and frozen to a predetermined product temperature.

[0003] The calcium chloride instant freezing method is superior in terms of cooling efficiency, freezing cost, etc. compared to other freezing methods. Further, according to the freezing method disclosed in Patent Document 1, even when instantaneously freezing a large fish body such as tuna with calcium chloride, frozen fish with good meat color can be produced without causing flesh cracking.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the method of freezing in two stages, such as the freezing method disclosed in Patent Document 1, has a slow passing speed through the ice crystal temperature zone (-2°C to -4°C), and it has been difficult to prevent dripping to maintain umami. When processing live fish to obtain frozen fish products, even if the general calcium chloride instant freezing method is simply adopted, it has never been possible to always produce frozen fish products with good freshness (low K value). The inventor of the present application has arrived at the present invention by repeatedly considering various trials on how to manage what processes when manufacturing frozen fish products using the calcium chloride instant freezing method.

[0006] An object of the present invention is to provide a method for manufacturing a frozen fish product that can always obtain a frozen fish product with good freshness (low K value).

Means for Solving the Problems

[0007] According to the present invention, the method for manufacturing a frozen fish product includes a bleeding step of bleeding the landed fish while it is alive, a shaping step of shaping the bled fish into loins, a vacuum packaging step of vacuum-packaging the loins obtained by shaping, a calcium chloride solution freezing step of freezing the vacuum package of the loins by putting it into a tank of calcium chloride solution at -35°C or lower, a calcium chloride solution removing step of removing the calcium chloride solution adhering to the surface of the vacuum package taken out from the tank of calcium chloride solution, and a boxing and packaging step of boxing and packaging the vacuum package from which the calcium chloride solution has been removed. In particular, by setting the time from the start of the shaping step to the start of the calcium chloride solution freezing step within 10 minutes for each loin, the K value of the loin is controlled to be 5.0 or less.

[0008] As a manufacturing process, it includes a bleeding and draining process, a shaping process, a vacuum packaging process, a calcium chloride solution freezing process, a calcium chloride solution removing process, and a boxing and packaging process. For each loin, the time from the start of the shaping process to the start of the calcium chloride solution freezing process is controlled to be within 10 minutes, so that the K value of the loin is 5.0 or less. When processing live fish to obtain frozen fish products, the time from the start of the work of shaping the fish into loins to the introduction into the calcium chloride solution is very important. As in the present invention, it is essential that this time is within 10 minutes for each loin. It has been confirmed that if this time exceeds 10 minutes, the K value cannot be maintained at 5.0 or less. Therefore, according to the present invention, frozen fish products with good freshness can always be obtained. In addition, after the loin obtained by shaping is vacuum-packaged, it is put into the tank of the calcium chloride solution, so that the loin can be protected from the strong pungency of the calcium chloride solution, and food contamination and food material drying can be achieved. In this specification, the loin refers to four parts, the dorsal side and the ventral side, obtained by dividing each fillet obtained by slicing the fish into three pieces in half.

[0009] It is preferable that the shaping process is a process that starts within 1 hour from the bleeding and draining process in a state where the bled and drained fish is put into a chilled seawater tank at approximately -2°C or lower.

[0010] It is also preferable that the calcium chloride solution freezing process is a process in which each vacuum package obtained by the shaping process is continuously stayed in the tank of the calcium chloride solution for 10 minutes or more.

[0011] In this case, it is preferable that the calcium chloride solution removing process and the boxing and packaging process are processes that end within 5 minutes for each vacuum package.

[0012] Furthermore, in this case, it is more preferable that the bleeding and draining process is a process in which each landed fish is bled and drained within 1 minute from landing.

[0013] It is also preferable that the calcium chloride solution freezing step is a step of forcibly circulating the calcium chloride brine in the tank of the calcium chloride solution into which the vacuum-packed shaped body is introduced.

[0014] It is also preferable that the vacuum packaging step is a step of removing the water adhering to the surface of the loin with water supply paper and then performing vacuum packaging.

[0015] It is also preferable to further include an ultra-low temperature storage step of storing the package obtained by the box packing step in an ultra-low temperature storage.

[0016] It is also preferable that the fish is yellowtail.

Advantages of the Invention

[0017] According to the present invention, by setting the time from the start of the shaping process to the start of the calcium chloride solution freezing process for each loin to within 10 minutes, the K value of the loin is controlled to be 5.0 or less. As a result, it is always possible to obtain a frozen fish product with good freshness. In addition, after the loin obtained by shaping is vacuum-packed, it is put into the tank of the calcium chloride solution, so that the loin can be protected from the strong pungency of the calcium chloride solution, and food contamination and food material drying can be achieved.

Brief Description of the Drawings

[0018]

Figure 1

Modes for Carrying Out the Invention

[0019] Hereinafter, an embodiment of the method for manufacturing a frozen fish product of the present invention will be described with reference to the drawings. In this embodiment, the fish is "yellowtail", and hereinafter, the case of manufacturing a frozen yellowtail product will be described. Of course, the present invention is similarly applicable to large fish other than yellowtail, such as sea bream, bonito, tuna, and others.

[0020] As shown in Fig. 1, the method for manufacturing frozen fish products of the present embodiment includes a bleeding step (step S1) of bleeding live caught sea bream by bleeding them alive, a shaping step (step S2) of shaping the live caught and bled sea bream into loins, a vacuum packaging step (step S3) of vacuum packaging the loins of sea bream obtained by shaping, a calcium chloride solution freezing step (step S4) of putting the vacuum package of the loins into a tank of calcium chloride solution at -35°C or lower for freezing, a calcium chloride solution removing step (step S5) of removing the calcium chloride solution adhering to the surface of the vacuum package taken out from the tank of calcium chloride solution, a boxing and packing step (step S6) of boxing and packing the vacuum package from which the calcium chloride solution has been removed, and an ultra-low temperature storage step (step S7) of storing the package obtained by the boxing and packing step in an ultra-low temperature warehouse. Hereinafter, these steps will be described in detail.

[0021] (Bleeding step, step S1) The sea bream caught from the live basket of sea bream farming is bled alive one by one on board, for example, by inserting a metal rod into the medulla oblongata. The bled alive sea bream is immediately put into a cold seawater tank at around -2°C for bleeding. Although this is just an example, in this case, the sea bream is put in at a ratio of 500 kg (100 pieces) of sea bream per 1 ton of cold seawater. The time from the catch from the live basket to the bleeding alive is within 1 minute. The K value of the sea bream at the time of catch is 1.5, and this K value remains 1.5 even in the cold seawater tank.

[0022] (Shaping step, step S2) Return to the port, put 5 tons (1000 pieces) of live-killed and bled hamachi that were bled on the same day into a new cold seawater tank (around -2°C) from the cold seawater tank with blood mixing, transport them to the processing factory, and store the cold seawater tank in a refrigerator. The cold seawater tank and the refrigerator are maintained at around -2°C. Then, every predetermined time (for example, every 13 minutes), a predetermined number (for example, 100 pieces) of hamachi are carried into the processing factory in the cold seawater tank (around -2°C), and the shaping process is started. The time from live-killing and bleeding to the start of the shaping process is within 1 hour. In a specific example, the time from live-killing and bleeding on the ship to returning to the port and starting the shaping process at the processing factory is about 1 hour. The K value of the hamachi at the start of the shaping process was 2.0.

[0023] The shaping process is carried out as follows, for example. (1) Cut the hamachi taken out from the cold seawater tank by a machine into the head, kama, body, internal organs, etc. Cut 1000 pieces in 8000 seconds (8 seconds / piece). (2) Cut the obtained body into three slices by a machine to make fillets, and further cut them into 4 loins (segments) on the dorsal and ventral sides. The processing time for 1000 pieces is about 2 hours and 13 minutes, and for 100 pieces it is 800 seconds (about 13 minutes, 8 seconds / piece). (3) Remove the skin of the loin by a machine and wash it with cold water. The K value of the loin during and at the end of the shaping process was 5.0.

[0024] (Vacuum packaging process, step S3) In a separate room, the water adhering to the surface of the loin after finishing the shaping process is removed with disposable water supply paper, placed on a backing paper and put into a vacuum packaging bag, and vacuum-packed. Next, in the separate room, it is confirmed by a metal detector that there are no metal foreign substances, and a weight display seal is attached to each package. In this way, by vacuum-packing the loin, the loin can be protected from the extremely pungent calcium chloride solution and food contamination and food material drying can be avoided. For each loin, the time required for the shaping process and vacuum packaging (that is, the time from the start of the shaping process to the start of the calcium chloride solution freezing process) is within 10 minutes, and in a specific example, it is 8 minutes. For each loin, it is very important that the time from the start of this shaping process to the start of the calcium chloride solution freezing process is within 10 minutes. It has been confirmed that if it exceeds 10 minutes, the freshness will decrease. In this embodiment, the K value of the loin at the end of the vacuum packaging was 5.0. Although it varies depending on the number of landed fish, the number of workers, etc., for all loins, the general time required for the shaping process and vacuum packaging was within 3 hours.

[0025] (Calcium Chloride Solution Freezing Process, Step S4) Immediately after the vacuum packaging is completed, the vacuum-packaged loins are placed into the calcium chloride liquid tank through its inlet. In the calcium chloride liquid tank, a portion of the calcium chloride brine, cooled to -35°C or lower by the brine cooler pump, is sprayed from above the inlet toward the outlet, and a portion of the calcium chloride brine is showered diagonally downward. As a result, the vacuum-packaged loins placed in the calcium chloride liquid tank flow toward the outlet, and the floating vacuum-packaged loins are also cooled. The calcium chloride brine is returned from the bottom of the tank to the brine cooler pump, where it is cooled and pressurized, and sprayed back into the calcium chloride liquid tank, and this forced circulation is repeated. A conveyor is provided near the outlet of the calcium chloride liquid tank, and the vacuum-packaged loins flowing through are successively removed from the calcium chloride liquid tank by this conveyor. In this way, in the calcium chloride bath, the calcium chloride brine cooled to -35°C or less is forced to circulate and sprayed out, so the loin placed in is continuously cooled and instantly frozen with seven times the cooling efficiency compared to air cooling, and passes through the "ice crystal temperature zone" that destroys the flavor of food in an overwhelming amount of time, so that very good flavor is maintained. Furthermore, calcium chloride brine is inexpensive and easy to procure, and the forced circulation significantly improves the freezing capacity compared to the capacity of the calcium chloride bath, making it possible to reduce capital investment. The time spent in the calcium chloride bath for each loin is 10 minutes or more, for example about 15 minutes. Incidentally, in the flowing calcium chloride brine at -35°C or less, the core temperature of a loin of about 500g is cooled to -30°C or less in 5 to 8 minutes. The K value of the loin during its stay in the calcium chloride bath and when it was removed from the calcium chloride bath was 5.0.

[0026] (Calcium chloride solution removal process, step S5) The vacuum-packaged loins were successively removed from the calcium chloride tank by the conveyor, and showered with 15°C fresh water from above and below to remove the calcium chloride liquid adhering to the surface of the vacuum-packaged loins. The K value of the loins in this calcium chloride liquid removal process was 5.0.

[0027] (Case packing process, step S6) The vacuum packages of loin from which the calcium chloride solution has been removed are boxed and packed at a rate of each number according to customer requirements. For example, in a 10 kg cardboard box, they are boxed and packed 20 at a time (20 loins / box). The working time for removing the calcium chloride solution and box-packing each vacuum package of loin is within 5 minutes, and in a specific example, it is 3 - 4 minutes. The K value of the loin at the completion of box-packing was 5.0. Although it varies according to the number of fish landed, the number of workers, etc., for all loins, the general time from the process of bleeding and exsanguination to the start of the ultra-low temperature storage process was within 6 - 8 hours.

[0028] (Ultra-low temperature storage process, step S7) The boxed packages are placed on a pallet 20 boxes (200 kg) at a time when boxed in a 10 kg cardboard box, and are carried into a -40°C ultra-low temperature storage by a forklift for storage. For each vacuum package of loin, the time from being taken out of the calcium chloride solution tank to starting ultra-low temperature storage is about 10 minutes. The K value of the loin at the time of being carried into the ultra-low temperature storage was 5.0.

[0029] It has been confirmed that the loin stored in a -40°C ultra-low temperature storage shows no discoloration of the body color even after 12 months, and this state is maintained even after 3 years, for example.

[0030] As described in detail above, in this embodiment, it includes a bleeding and blood-letting process, a shaping process, a vacuum packaging process, a calcium chloride solution freezing process, a calcium chloride solution removing process, a boxing and packing process, and an ultra-low temperature storage process as manufacturing processes. In particular, in order to maintain the K value of the loin at 5.0 or less, the time from the start of the shaping process to the start of the calcium chloride solution freezing process for each loin is set within 10 minutes. When processing live fish to obtain frozen fish products, the time from the start of the operation of shaping the fish into loins to the introduction into the calcium chloride solution is very important. It has been confirmed that if this time exceeds 10 minutes, the K value cannot be maintained at 5.0 or less. According to this embodiment, since this time is controlled within 10 minutes, frozen fish products with good freshness can definitely be obtained. Also, after the loin obtained by shaping is vacuum-packaged, it is put into the tank of the calcium chloride solution, so the loin can be protected from the intense sharpness of the calcium chloride solution, and food contamination and food material drying can be achieved.

Example

[0031] The relationship between the time from the start of the shaping process to the start of the calcium chloride solution freezing process and the K value for each loin was actually tested and confirmed. Specifically, receiving the caught sea bream (live fish) at the port, after performing bleeding and blood-letting processing in the same way as in the embodiment, shaping it into loins, immediately vacuum-packaging it, then instantaneously freezing it in the calcium chloride solution, and storing it in an ultra-low temperature warehouse at -45°C. The time from bleeding to the start of shaping into loins was 5 minutes, and the caught sea bream was put into a cold seawater tank at around -2°C for processing. The indoor temperature in the processing factory was 15°C.

[0032] Regarding the instant frozen product samples with the time from the start of the shaping process to the start of the calcium chloride solution freezing process set to 4 minutes, 7 minutes, 10 minutes, 11 minutes, 15 minutes, and 25 minutes, tests were conducted to measure the K value for each. This test was carried out at the Fukuoka Food Inspection Office of the Japan Food Inspection General Incorporated Foundation, which is a registered inspection agency of the Ministry of Health, Labour and Welfare, on October 29, 2024. The test method for the K value was the high-performance liquid chromatography method. The test results are shown in Table 1.

[0033]

Table 1

[0034] From Table 1, it was clearly proven that when the time from the start of the shaping process to the start of the calcium chloride solution freezing process exceeded 10 minutes to 11 minutes (Sample 4), the K value became 7 and the freshness decreased, and when the time from the start of the shaping process to the start of the calcium chloride solution freezing process was within 10 minutes (Samples 1, 2, and 3), the K value was maintained at 5 or less and the freshness could be maintained.

[0035] All of the above-described embodiments are illustrative of the present invention and not restrictive, and the present invention can be implemented in various other modified and changed forms. Therefore, the scope of the present invention is defined only by the scope of the claims and its equivalent scope.

Explanation of Signs

[0036] S1 Live tying and blood draining process S2 Shaping process S3 Vacuum packaging process S4 Calcium chloride solution freezing process S5 Calcium chloride solution removal process S6 Boxing and packaging process S7 Ultra-low temperature storage process

Claims

1. The method for producing frozen fish comprises a live-killing and bleeding step of killing and draining the blood of landed fish, a shaping step of shaping the live-killed and bled fish into loins, a vacuum packaging step of vacuum-packaging the shaped and processed loins, a calcium chloride liquid freezing step of placing the vacuum-packaged loins in a tank of calcium chloride liquid at -35°C or lower and freezing them, a calcium chloride liquid removing step of removing the calcium chloride liquid adhering to the surface of the vacuum-packaged products removed from the tank, and a boxing step of boxing the vacuum-packaged products from which the calcium chloride liquid has been removed, wherein the time from the start of the shaping step to the start of the calcium chloride liquid freezing step for each loin is controlled to be within 10 minutes, so that the K value of the loin is controlled to be 5.0 or less.

2. The manufacturing method of the frozen fish product according to claim 1, characterized in that the shaping process is a process that starts within one hour of the live-killing and bleeding process in a state where the live-killed and bleeding fish is placed in a cold seawater tank at approximately -2 ° C or less.

3. 2. The method for producing frozen fish products according to claim 1, characterized in that the calcium chloride liquid freezing step is a step of allowing each vacuum packaged body obtained by the shaping processing step to remain in the tank of calcium chloride liquid for 10 minutes or more.

4. 4. The method for producing frozen fish products according to claim 3, wherein the calcium chloride liquid removing step and the boxing step are completed within 5 minutes for each vacuum package.

5. 5. The method for producing frozen fish products according to claim 4, wherein the step of bleeding the fish while it is alive is a step of bleeding the fish while it is alive within one minute after it is landed.

6. 2. The method for producing frozen fish products according to claim 1, characterized in that the calcium chloride liquid freezing step is a step of forcibly circulating calcium chloride solution in the tank into which the vacuum-packaged shaped bodies are placed.

7. 2. The method for producing frozen fish products according to claim 1, wherein the vacuum packaging step is a step of removing water adhering to the surface of the loin with water-absorbing paper and then vacuum packaging the loin.

8. 2. The method for producing frozen fish products according to claim 1, further comprising an ultra-low temperature storage step of storing the packaged body obtained by the boxing step in an ultra-low temperature storage.

9. 2. The method for producing frozen fish products according to claim 1, wherein the fish is yellowtail.

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