JP2021048839A - Production method of frozen mackerel - Google Patents

Abstract

To provide a high quality mackerel to consumers.SOLUTION: An operator lands, from a crawl W in a ship S, a mackerel ML raised from the sea, and then, immediately kills the mackerel ML on the ship S (ST1). Hereby, the mackerel ML becomes a dead mackerel MD. The operator inputs the mackerel MD into a tank T on the ship S into which ice CI and sea water SW are input (ST2). The operator drains blood from the mackerel MD in the tank T (ST2). The operator performs CAS freezing of the mackerel MD in a CAS freezer FR1 (ST7).SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing frozen mackerel.

Increasingly, consumers who eat raw mackerel become food poisoning due to a parasite called Anisakis. For this reason, it has become more difficult to sell mackerel for raw consumption than it was several years ago.
For this reason, Anisakis is killed by freezing, and the sale of frozen mackerel has been studied in recent years.
However, the frozen mackerel is already discolored at the time of thawing, and it looks unattractive, and a decrease in commercial value is unavoidable.
Therefore, in order to prevent discoloration of mackerel, a technique of adding an additive to mackerel at the treatment stage has been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2003-334035

However, since the mackerel to which the prior art is applied, including the technique described in Patent Document 1 described above, contains additives, the consumer may feel uncomfortable or the taste may be impaired. , It is hard to say that the quality as a product is good.
In other words, it is a situation where high quality mackerel cannot be provided to consumers.

The present invention has been made in view of such a situation, and an object of the present invention is to provide consumers with high-quality mackerel.

In order to achieve the above object, the method for producing frozen mackerel according to one aspect of the present invention is:
After landing the mackerel, the lively step to make the mackerel live, and
A blood draining step for draining blood from the lived mackerel,
A CAS freezing step of freezing CAS on the drained mackerel,
including.

Further, the method for producing frozen mackerel according to one aspect of the present invention is as follows.
The chilling step of chilling the bleeding mackerel with slurry ice is further included.
The CAS freezing step is a step of freezing the CAS with respect to the cooled mackerel.
Can be done.

According to the present invention, it is possible to provide consumers with high-quality mackerel.

It is a figure which shows the outline of the processing process from the time when mackerel is lifted from the sea to the time when frozen mackerel is produced and shipped. It is a flowchart which shows the process from landing of mackerel to temporary storage in a refrigerator. It is a flowchart which shows the process from the unloading from a refrigerator to the shipment of mackerel. It is a figure which shows the relationship between the thawing time and the drip amount when each sample is thawed using a plurality of frozen mackerel including the frozen mackerel produced by the production method to which this invention is applied as a sample. It is a table explaining each sample used in the analytical test. It is a figure which shows the result of the analysis test when each sample was thawed. It is a figure which shows the degree of discoloration of the body when the sample | sample explained in FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an outline of a processing process from when mackerel is lifted from the sea to when it is produced as frozen mackerel and shipped by using the method for producing frozen mackerel to which one embodiment of the present invention is applied. ..
Hereinafter, the method shown in FIG. 1 as an embodiment of the present invention will be referred to as "the present production method".

In the following description, the code ML is attached to the mackerel in the living state, and the code MD is attached to the mackerel in the dead state.
In step ST1, the worker temporarily stores the mackerel ML raised from the sea in the cage W in the ship S. After that, the worker lands the mackerel ML from the cage W. The worker puts the mackerel ML alive on the ship S. In this way, the mackerel ML becomes a mackerel MD by being activated on the ship S.
The term "live" here means that the mackerel ML is immediately killed to make it a mackerel MD.
In the present embodiment, the mackerel ML is made into a mackerel MD by quickly destroying its nerves to put it in a suspended state, then draining blood and immediately killing it, thereby making it "live".

In step ST2, the worker puts the mackerel MD into the tank T on the ship S containing the ice CI and the seawater SW. Then, the worker drains blood from the mackerel MD in the tank T.
When the blood-drained mackerel MD is unloaded, the process proceeds to step ST3.

In step ST3, the worker puts the landed mackerel MD into the slurry ice SI.
Here, the slurry ice SI refers to a mixture of extremely small ice particles and cold water containing salt. The slurry ice SI has a feature that the temperature can be arbitrarily set depending on the salt concentration and the ratio of the amount of extremely small ice particles to the amount of salt water.
Since such slurry ice SI is fine and has a large surface area, the heat of the mackerel MD after the step ST3 is performed is quickly taken away, and it becomes possible to prevent a decrease in freshness. Further, in the mackerel MD after the step ST3 is performed, the ice of the slurry ice SI prevents scratches, deformations, burns, and cracks on the surface of the fish body. By performing the step ST3 in this way, the commercial value of the mackerel MD can be increased.

In step ST4, the worker removes the scales, head and internal organs from the mackerel MD. Next, the worker cleans the abdomen of the mackerel MD with running water. Then, the worker lowers the three mackerel MDs in the dedicated process of cutting the three pieces. Hereinafter, the fillet F of the mackerel MD obtained as a result of cutting three pieces is referred to as "raw material fillet F". After that, the worker trims and shapes the raw material fillet F. Here, trimming and shaping means adjusting the shape of the raw material fillet F. Hereinafter, the raw material fillet F that has been trimmed and shaped is particularly referred to as "fillet F".

In step ST5, the worker temporarily stores the fillet F in the raw material refrigerator RE.
When the fillet F is temporarily stored in the raw material refrigerator RE in this way, the process proceeds to step ST6.

In step ST6, the worker vacuum-packs the fillet F. Hereinafter, the vacuum-packed fillet F is referred to as a “fillet P”.

In step ST7, the worker performs CAS freezing on the fillet P in the freezer FR1 for freezing CAS (registered trademark) (hereinafter referred to as “CAS freezer FR1”).
The CAS freezing here means that the water molecules inside the material (fillet) are supercooled using a quick freezer (CAS freezer FR1) equipped with a special CAS generator (manufactured by Abbey Co., Ltd.). A technology that maintains, prevents ice crystallization, and freezes the cell tissue of the material without destroying it.

In step ST8, the worker packs the CAS-frozen fillet P in a box. Then, the worker produces the product B by packing the boxed fillet P.
In step ST9, the worker stores the product B in the freezer FR2.
In step ST10, the worker ships the product B from the factory.

In this way, in the present production method, the worker generates the mackerel MD by landing the mackerel ML and then quickly activating it on the ship S, and drains the blood while cooling the mackerel MD. do.
Then, after landing the mackerel MD, the worker cools it with slurry ice SI and then performs a fillet treatment to generate a fillet F. Further, the worker CAS freezes the fillet F and stores it at a low temperature until shipment.
As described above, in this production method, the live step (step ST1), the blood draining step (step ST2), the low temperature maintenance at the distribution and manufacturing timing, and the CAS freezing step (step ST3, step ST5, step ST7). And step ST9) are combined. As a result, when the product B (fillet F of mackerel MD) produced by applying this production method is thawed, the degree of discoloration is suppressed as compared with the conventional one.

Next, with reference to FIG. 2, a detailed flow of the process from the landing of the mackerel ML to the temporary installation of the fillet F in the refrigerator will be described, which corresponds to steps ST1 to ST5 of FIG.
FIG. 2 is a flowchart showing a process from landing of mackerel to temporary storage in a refrigerator.

In step S1, the worker temporarily stores the mackerel ML raised from the sea in the cage W in the ship S. After that, the worker lands the mackerel ML from the cage W.
In step S2, the worker activates the mackerel ML on the ship S.
The above steps S1 and S2 correspond to step ST1 in FIG. 1 described above.

The present production method can produce the following effects by having the steps of step S1 and step S2.
That is, in the past, mackerel that had been caused to die of natural causes by being landed began to rot after death, and its freshness decreased accordingly. In addition, the mackerel may be injured due to the violence of the mackerel between the time it was landed and the time it died of natural causes. In addition, the violence caused fatigue substances to accumulate on the body of the mackerel, and its taste deteriorated.
On the other hand, by applying this production method, the mackerel ML is killed by being activated after landing and becomes a mackerel MD. Therefore, it is possible to prevent scratches on the body of the mackerel MD and deterioration of the taste. In addition, the mackerel MD after being alive in this way has a delayed onset of putrefaction as compared with the case of natural death, so that it is possible to prevent a decrease in freshness.
In this way, in step S2, the mackerel ML is activated on the ship S to generate the mackerel MD, so that it is possible to prevent scratches and deterioration of the taste of the mackerel MD and to improve the freshness. This production method can exert the effect that the decrease can be delayed.

Here, in the present production method, the mackerel ML raised from the sea in step S1 before step S2 is put into the cage W on the ship S. At that time, if the mackerel ML is kept in the cage W for a long time, it comes into contact with other fish in the cage W and the body is injured. In addition, the stress caused by contact causes fatigue substances to accumulate, and the taste of mackerel ML deteriorates.
Therefore, in step S1, the shorter the time from when the mackerel ML is temporarily stored in the cage W to when it is landed, the more it is possible to prevent the mackerel ML from being scratched and the taste from being deteriorated. , The above-mentioned effect becomes more remarkable.

After step S2 having such an effect, the following steps of step S3 are performed.
That is, in step S3, the worker puts the mackerel MD into the tank T on the ship S in which the ice CI and the seawater SW are put. Then, the worker drains blood from the mackerel MD in the tank T.

The present production method can achieve the following effects by having such a step S3.
That is, even if the mackerel ML is activated and becomes the mackerel MD, if the mackerel MD is left at room temperature, histamine that causes allergy-like food poisoning is produced, so that there is a risk of developing histamine-producing bacteria. Will be higher. Therefore, it is desirable to control the mackerel MD at a low temperature. Therefore, in the present production method, in step S3, the live mackerel MD is put into the tank T containing the ice CI and the seawater SW, that is, the low temperature tank T.
Furthermore, even if the mackerel MD is kept alive, if it is left untreated without sufficient blood drainage, blood will circulate in its body, causing a decrease in freshness and a fishy odor. Since the remaining blood of mackerel MD is oxidized, its body discolors when it is thawed after freezing. Therefore, in this production method, in order to prevent the mackerel MD from being deteriorated in freshness or discolored, the mackerel MD obtained as a result of being activated in step S2 is immediately drained in step S3.
In this way, in the step S3, the mackerel MD obtained as a result of the activation of the mackerel ML is drained on the ship S, so that the mackerel MD loses its freshness, smells, and its body. Since the effect of preventing discoloration of mackerel and the use of ice CI when draining blood keeps the mackerel MD at a low temperature, it is possible to further prevent the deterioration of freshness and the risk of food poisoning caused by histamine. This production method can exert the effect of being able to suppress the above.

The above step S3 corresponds to step ST2 in FIG. 1 described above.

In step S4, the worker lands the mackerel MD.
In step S5, the worker puts the landed mackerel MD into the slurry ice SI. Here, it is preferable that a slurry ice SI having a salt concentration of 1.5% is adopted. When the salt concentration of the slurry ice SI reaches 1.5%, the center temperature of the mackerel MD (hereinafter referred to as "core temperature") while being charged into the slurry ice SI becomes -1.5 ° C to 1.0 ° C. This is because it is kept within the range of.
In step S6, the worker transports the mackerel MD in the state of being charged into the slurry ice SI to the processing facility. During this period, the core temperature of the mackerel MD is maintained at, for example, −1.5 ° C. to 1.0 ° C.
The above steps S4 to S6 correspond to step ST3 in FIG. 1 described above.

In step S7, the worker removes scales from the mackerel MD.
In step S8, the worker removes the head and internal organs of the mackerel MD.
In step S9, the worker washes the abdomen of the mackerel MD with running water.
In step S10, the worker produces the raw material fillet F by lowering three mackerel MDs in a dedicated process for cutting three sheets.
In step S11, the worker cleans the raw material fillet F with running water.
In step S12, the worker produces the fillet F by trimming and shaping the raw material fillet F.
The above steps S7 to S12 correspond to step ST4 of FIG. 1 described above.

In step S13, the worker carries the fillet F into the refrigerator RE and temporarily stores it. The temperature inside the refrigerator at this time is preferably 10 ° C. or lower. This is because by setting the temperature in the refrigerator R to 10 ° C. or lower, it is possible to prevent a decrease in the freshness of the fillet F and prevent the generation of histamine-producing bacteria that cause the generation of histamine.
The above step S13 corresponds to step ST5 of FIG. 1 described above.

As described above, with reference to FIG. 2, the detailed flow of the process from landing to storage in the refrigerator corresponding to steps ST1 to ST5 of FIG. 1 has been described.
Next, with reference to FIG. 3, a detailed flow of the process from unloading the mackerel from the refrigerator to shipping, which corresponds to steps ST6 to ST10 of FIG. 1, will be described.

FIG. 3 is a flowchart showing a processing process of mackerel from unloading from the refrigerator to shipping.
In step S21, the worker carries out the fillet F from the refrigerator.
In step S22, the worker washes the fillet F with chiller sterilized water. Here, the chiller sterilized water refers to a mixture of chiller water and sodium hypochlorite. The temperature of the chiller water at this time is preferably 10 ° C. or lower, and the concentration of sodium hypochlorite mixed in the chiller water is preferably 200 ppm.
In step S23, the worker wipes off the water in the fillet F.
In step S24, the worker creates the fillet P by vacuum-packing the fillet F.
The above steps S21 to S24 correspond to step ST6 of FIG. 1 described above.
In step S25, the worker performs CAS freezing on the packaged fillet P.
The above step S25 corresponds to step ST7 of FIG. 1 described above.

The present production method can produce the following effects by having the step S25.
That is, in normal freezing, the cell tissue is destroyed by crystals formed by collecting water molecules in the material and the material is damaged, and when the material is thawed, the damage causes the so-called drip inside the cell. Nutrients and water flow out. The drip contains a large amount of the umami component of the material, for example, IMP (inosin-phosphoric acid), which is known as the umami component when the material is mackerel, and the outflow of these contains a decrease in taste. Will be invited. In addition, the moisture of the material also flows out, which inevitably reduces the texture.
In addition, when slowly frozen in a normal freezing device, the lipids in the material are oxidized due to the influence of oxygen in the air. Especially when the material is mackerel, the lipid is particularly easily oxidized, and the influence of this oxidation causes deterioration of taste and texture.
Therefore, in step S25, as described above, CAS freezing is performed on the packaged fillet P to instantly freeze the fillet F (mackerel MD) to the center while keeping the tissue alive. Can be done. Therefore, this production method can exert the effect that the outflow of umami components such as IMP and water and the oxidation of mackerel can be suppressed at the time of thawing.
Furthermore, by lowering the temperature of CAS freezing to -30 ° C or lower, the parasite Anisakis attached to the body of fillet F (mackerel MD) is killed, so the risk of food poisoning caused by Anisakis can be reduced. The effect can also be achieved by this production method.

In step S26, the worker inspects the packaged fillet P for metal.
In step S27, the worker packs the packaged fillet P into a box.
In step S28, the worker packs the boxed fillet P.
The above steps S26 to S28 correspond to step ST8 in FIG. 1 described above.

In step S29, the worker stores the product B in the freezer FR2. The temperature inside the freezer at this time is preferably −30 ° C. or lower.
The above step S29 corresponds to step ST9 in FIG. 1 described above.

In step S30, the worker ships the product B from the factory.
The above step S30 corresponds to step ST10 in FIG. 1 described above.

As described above, this production method is used in the livelihood on board (step ST1 in FIG. 1 and step S2 in FIG. 2) and blood removal (step ST2 in FIG. 1 and step S3 in FIG. 2), distribution and manufacturing process. Core temperature control at low temperature (step ST3, step ST5, step ST9 in FIG. 1, step S3 in FIG. 2, step S5, step S13, step S22 and step S29), and CAS freezing step (step ST7 in FIG. 1 and step S29). This is a method in which step S25) of FIG. 2 is combined.
As a result, this production method has the effect of providing consumers with mackerel that does not discolor itself, is highly safe, and maintains its original taste and texture.

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.

The distribution and manufacturing process of mackerel has been divided from the past, and the temperature control of mackerel is entrusted to each process. For example, a worker in a certain process does not know the management status of mackerel in the previous process, and does not inform the worker in the next process of the management status of mackerel in his own work. Moreover, he does not know the influence of the management status of mackerel in his own work on the mackerel as a product.
In other words, even if the worker sets the control temperature independently in each process, that temperature is not always the best temperature for the mackerel as a product.
From the above, it is desirable that the temperature of mackerel is controlled in a series in the distribution and manufacturing process of mackerel.
Therefore, for example, the record of the control temperature of mackerel in the distribution and manufacturing process may be managed as data, and the most suitable temperature control standard for mackerel may be introduced into the distribution and manufacturing process.

Moreover, the above-mentioned temperature control standard and the freshness of mackerel may be linked.
Here, the k value is used as an index indicating the freshness of mackerel, and the k value fluctuates depending on the environment such as the outside air temperature. Therefore, the control temperature of mackerel can be finely adjusted based on the relationship between the k value and the control temperature of mackerel. That is, by adjusting the control temperature of mackerel according to the k value, it is possible to obtain mackerel with a certain degree of freshness.
That is, by thoroughly controlling the core temperature of mackerel in the distribution and manufacturing processes, it is possible to provide mackerel of stable quality.

Further, for example, in the distribution and manufacturing processes, not only the k value but also the value of TBA indicating the amount of IMP and the degree of oxidation of the lipid of mackerel may be associated with the above-mentioned temperature control standard. Based on the correlation between the k value, the IMP amount, and the TBA value, the basis for the high freshness of mackerel can be shown numerically.
By indicating the quality of mackerel numerically in this way, it is possible for those who purchase mackerel to stably obtain high quality mackerel.

This production method is not limited to mackerel, and may be applied to other types of fish.

Summarizing the above, the frozen mackerel production method to which the present invention is applied suffices to have the following configuration, and various other embodiments can be adopted in addition to the above-described embodiment.
That is, the method for producing frozen mackerel includes a live step (for example, step ST1 in FIG. 1 and step S2 in FIG. 2) for activating the mackerel after landing the mackerel (for example, mackerel ML in FIG. 1).
A blood draining step (step ST2 in FIG. 1 and step S3 in FIG. 2) for draining blood from the lived mackerel (for example, mackerel MD in FIG. 1)
A CAS freezing step (step ST7 in step 1 and step S25 in FIG. 2) in which CAS freezes the mackerel from which blood has been drained.
including.

This can have the effect of providing consumers with high-quality mackerel.
Hereinafter, this effect will be specifically described.

The present inventors conducted the following first experiment.
A. After landing the mackerel, the workers did not drain the blood on the ship, and after landing the mackerel, the mackerel was made into a fillet without cooling, and the fillet was frozen by CAS. As a result, the thawed mackerel discolored.
B. After landing the mackerel, the workers did not drain the blood alive on the ship, and after landing the mackerel, they cooled it and made it into a fillet, and then the fillet was frozen by CAS. As a result, the thawed mackerel discolored.
C. After landing the mackerel, the workers drained the blood lively on the ship, and after landing the mackerel, the mackerel was made into a fillet without cooling, and the fillet was frozen by CAS. As a result, it was found that the color of the thawed mackerel became much better.
D. After landing the mackerel, the workers drained the blood lively on the ship, and after landing the mackerel, it was cooled and then made into a fillet, and the fillet was frozen by CAS. As a result, almost no discoloration was seen in the thawed mackerel.

From the results of Experiment A and Experiment B, it was found that the mackerel was discolored when it was thawed only by CAS freezing.
From the results of Experiment C, it was found that the color of the mackerel at the time of thawing was significantly improved by removing the liveliness and blood of the mackerel against the freezing of CAS.
That is, the method for producing frozen mackerel to which the present invention is applied has three steps: CAS freezing, liveliness, and blood removal. Since these three steps are executed to produce frozen mackerel, the effect of eliminating discoloration of the body during thawing can be obtained.

Also, by freezing the mackerel with CAS, Anisakis is killed. Then, by subjecting the mackerel to a low temperature treatment called CAS freezing, the risk of deterioration of freshness and the generation of histamine is reduced. This has the effect of obtaining a highly safe mackerel.
In addition to CAS freezing, the risk of deterioration of freshness and generation of histamine is further reduced by performing low temperature treatment as in the above-described embodiment in the steps of liveliness and blood removal.
Furthermore, when CAS is frozen, the effect that the original taste and texture of mackerel can be obtained can be obtained.

Summarizing the above, the method for producing frozen mackerel to which the present invention is applied has the effect that it is possible to provide mackerel that does not discolor itself, is highly safe, and maintains the original taste and texture. Play.

Further, a cooling step (step ST3 in FIG. 1 and step S5 in FIG. 2) of cooling the drained mackerel with slurry ice is further included.
The CAS freezing step is a step of freezing the CAS with respect to the chilled mackerel.
Can be done.
As a result, the above-mentioned effect of not discoloring the body, being highly safe, maintaining the original taste and texture, that is, being able to provide high-quality mackerel becomes more remarkable. ..

The inventors conducted the second experiment shown below in order to demonstrate the above-mentioned effect.
The results of the second experiment will be described with reference to FIGS. 4 to 7.

FIG. 4 is a diagram showing the relationship between the thawing time and the amount of drip when a plurality of frozen mackerels including frozen mackerel produced by the production method to which the present invention is applied are used as samples and each sample is thawed.
As described above, the drip that flows out from the material is formed by destroying the cell tissue of the material at the time of thawing, and thereby the water and umami components in the material flow out. Therefore, it means that the smaller the amount of drip, the better the quality of the sample because the water content and the umami component in the material are retained.

First, each sample will be described.
Product Z is a sample (frozen mackerel) produced by the production method of the present invention, and is produced by the following processing step. First, the mackerel ML is landed, and then the workers drain the blood on the ship to make it a mackerel MD. After that, the mackerel MD is landed and then put into the slurry ice SI to be cooled. After that, the mackerel MD is processed into a fillet F by a worker, and CAS is frozen in the state of the fillet F.

On the other hand, Specimen 1 and Specimen 2 are specimens (frozen mackerel) produced by a conventional production method.
Specimen 1 is a sample (frozen mackerel) produced by the following production method. First, after the mackerel ML is landed, it is made into a mackerel MD by the workers because it is not alive and blood drained (naturally killed) on the ship. After that, the mackerel MD is landed and then put into a container containing ice CI and seawater SW to be cooled. After that, the mackerel MD is processed into a fillet F by a worker, and CAS is frozen in the state of the fillet F.
Specimen 2 is a sample (frozen mackerel) produced by the following production method. First, after the mackerel ML is landed, it is made into a mackerel MD by the workers because it is not alive and blood drained (naturally killed) on the ship. After that, the mackerel MD is unloaded and then put into a container containing a seawater SW. After that, the mackerel MD is processed into a fillet F by a worker, and CAS is frozen in the state of the fillet F.

Then, the inventors thawed each of Product Z, Specimen 1 and Specimen 2 by leaving them in a refrigerator at 5 ° C. for 24 hours or more. Next, the inventors measured the amount of drip generated in each sample for each standing time. The numerical values in the table of FIG. 4 indicate the weight of each sample, and the numerical values in parentheses indicate the amount of change in weight (the amount of drip generated from the sample) as compared with the sample before thawing.
Further, here, in order to clarify the comparison with the product Z produced by the production method of the present invention, a frozen mackerel of another company's product that may have been produced by some conventional production method (hereinafter, abbreviated as "other company's product"). The inventors thawed the product under the same conditions as the product Z (leave it in a refrigerator at 5 ° C.), measured the amount of drip generated, and displayed the results in the rightmost column in the table of FIG. Indicated.

From the results 24 hours after thawing in FIG. 4, in product Z, the amount of drip generated at the time of thawing was the smallest at 4 g. On the other hand, in the sample 2, the amount of drip generated at the time of thawing was the largest at 10 g.
That is, it was confirmed that the quality of the product Z was the best and the quality of the sample 2 was not the best after 24 hours of thawing.

As described above, the sample 2 is CAS-frozen in a state in which the naturally killed mackerel ML is not cooled (only put into the seawater SW). On the other hand, the product Z is a product that has been lived, drained, chilled with slurry ice SI, and frozen by CAS.
As described above, CAS freezing itself has been conventionally used as one of the freezing methods for suppressing the occurrence of drip as compared with the usual freezing method. However, as the result of FIG. 4 shows, the quality of the sample 2 in which this CAS freezing is simply performed is not good.
On the other hand, the quality of product Z, which is not only the CAS freezing, but also the treatment of the CAS freezing, which is a combination of the treatment of liveness, blood removal, and cooling with slurry ice SI. Is the best.
Therefore, it was shown that the quality can be improved because the drip generated at the time of thawing can be significantly suppressed by further treating the liveness, blood removal, and cooling with slurry ice SI in combination with CAS freezing.

Next, with reference to FIGS. 5 and 6, an analytical test in which each sample is thawed will be described using a plurality of frozen mackerel including frozen mackerel produced by the production method to which the present invention is applied as samples.

First, each sample will be described with reference to FIG.
FIG. 5 is a table illustrating each sample used in the analytical test.

Product Z is the same as that shown in FIG.
On the other hand, each of Specimen 3 to Specimen 5 is a sample (frozen mackerel) produced by each of several conventional production methods.
Specimen 3 is a sample (frozen mackerel) produced by the following production method. After being landed, the mackerel ML is naturally killed on board by a worker and made into a mackerel MD. After that, the mackerel MD is landed and then put into the slurry ice SI to be cooled. After that, the mackerel MD is processed into a fillet F by a worker, and CAS is frozen in the state of the fillet F.
Specimen 4 is a sample (frozen mackerel) produced by the following production method. First, the mackerel ML is landed and then naturally killed on board by a worker to be made into a mackerel MD. After that, the mackerel MD is landed and then put into a container containing ice CI and seawater SW to be cooled. After that, the mackerel MD is processed into a fillet F by a worker, and is frozen in a normal freezing device in the state of the fillet F.
Specimen 5 is a sample (frozen mackerel) produced by the following production method. First, the mackerel ML is landed and then naturally killed on board by a worker to be made into a mackerel MD. After that, the mackerel MD is unloaded and then put into a container containing a seawater SW. After that, the mackerel MD is processed into a fillet F by a worker, and is frozen in a normal freezing device in the state of the fillet F.

Then, the inventors thawed the product Z and each of the samples 3 to 5 by leaving them in a refrigerator at 5 ° C. Next, the inventors conducted an analytical test shown in FIG. 6 on each of the thawed samples.
FIG. 6 is a diagram showing the results of an analytical test when each sample was thawed.

As a first test, the inventors measured the IMP content per unit weight contained in each sample.
As described above, IMP is known as an umami component and is said to flow out as part of the drip generated when the material is thawed. Therefore, the larger the amount of the umami component contained in the thawed sample, the better the quality.

From the measurement results, the IMP content of product Z was the highest at 0.23 g / 100 g. On the other hand, in Specimen 3, the IMP content was the lowest at 0.17 g / 100 g.
From this, it was confirmed that the quality of product Z was the best and the quality of sample 3 was not the best.

Specimen 3 is a mackerel ML that has died of natural causes and is CAS-frozen in a state where it has been chilled with slurry ice SI. On the other hand, the product Z is a product that has been lived, drained, chilled with slurry ice SI, and frozen by CAS.
That is, the sample 3 in which the naturally killed mackerel ML is only CAS-frozen in a state where it has been cooled with slurry ice SI cannot suppress the outflow of IMP (umami component). That is, the quality of the sample 3 is not good.
On the other hand, Product Z is a combination of not only chilling and CAS freezing by slurry ice SI, but also lively and blood draining treatment for this chilling and CAS freezing.
Therefore, the outflow of IMP (umami component) at the time of thawing can be significantly suppressed by combining the chilling with slurry ice SI and the freezing of CAS, and the treatment of liveliness and blood removal, so that the quality of mackerel is good. Was shown to be able to be obtained.

As a second test, the inventors measured the TBA value of each sample.
As described above, the TBA value is an index indicating the degree of oxidation of the lipid of the material. Therefore, the smaller the TBA value, the smaller the degree of oxidation of the lipid of the material, and the better the quality.

From the measurement results, the TBA value of product Z was the smallest at 15 nmol / g. On the other hand, in sample 3, the TBA value was the highest at 74 nmol / g.
From this, it was confirmed that the quality of product Z was the best and the quality of sample 3 was not the best.

Specimen 3 is a mackerel ML that has died of natural causes and is CAS-frozen in a state where it has been chilled with slurry ice SI. On the other hand, the product Z is a product that has been lived, drained, chilled with slurry ice SI, and frozen by CAS.
That is, the sample 3 in which the naturally killed mackerel ML was only CAS-frozen in a state where it was cooled with slurry ice SI could not suppress the oxidation of lipids. That is, the quality of the sample 3 is not good.
On the other hand, Product Z is a combination of not only chilling and CAS freezing by slurry ice SI, but also lively and blood draining treatment for this chilling and CAS freezing.
Therefore, it is possible to suppress the oxidation of lipids at the time of thawing by further combining the treatment of chilling with slurry ice SI and the freezing of CAS, and the treatment of liveliness and blood removal, so that a high-quality mackerel can be obtained. It was shown that it can be done.

As a third test, the inventors measured the k-value of each sample.
As described above, the k value is an index indicating the freshness of the material. Therefore, the smaller the k value, the more fresh the sample is maintained and the better the quality. It is also generally said that if the k value is 20% or less, it can be used as sashimi.

From the measurement results, in product Z, the k value was the smallest, 1% or less. On the other hand, in sample 3, the k value was 22%, which was overwhelmingly high.
From this, it was confirmed that the product Z had the highest quality so that it could be used as sashimi, while the sample 3 had the lowest quality so that it was unsuitable for use as sashimi.

Specimen 3 is a mackerel ML that has died of natural causes and is CAS-frozen in a state where it has been chilled with slurry ice SI. On the other hand, the product Z is a product that has been lived, drained, chilled with slurry ice SI, and frozen by CAS.
That is, the sample 3 in which the naturally killed mackerel ML was only CAS-frozen in a state where it was chilled with slurry ice SI could not maintain its freshness after its thawing. That is, the quality of the sample 3 is not good.
On the other hand, Product Z is a combination of not only chilling and CAS freezing by slurry ice SI, but also lively and blood draining treatment for this chilling and CAS freezing. S
Therefore, the freshness of mackerel can be maintained even after thawing by combining the treatment of chilling with slurry ice SI and freezing of CAS, and the treatment of liveliness and blood removal, so that high-quality mackerel can be obtained. It was shown that it can be done.

From the analysis results of the IMP content, TBA value, and k value of each sample described with reference to FIGS. 5 and 6, the quality of the sample produced by the conventional production method is not good, while the present It was proved that the quality of the mackerel produced by the production method was good.

Finally, the discoloration of the mackerel after thawing will be described.
FIG. 7 is a diagram showing the degree of discoloration of the body when each sample is thawed. That is, FIG. 7 is a diagram showing the degree of discoloration of the body when the sample described in FIG. 4 is thawed.
As explained above, discoloration of the body is said to occur due to the oxidation of blood remaining in the body of the material. Therefore, from the viewpoint of preventing the fishy odor caused by the remaining blood and the appearance, it means that the quality is better as the body does not discolor.

The inventors thawed each of Product Z, Specimen 1 and Specimen 2 by leaving them in a refrigerator at 5 ° C. for 24 hours or more. Next, the inventors observed the degree of discoloration of the body of each sample every time it was left to stand.
Further, here, in order to clarify the comparison with the product Z produced by the production method of the present invention, the inventors of other companies also use the same conditions as the product Z (leave in a refrigerator at 5 ° C.). It was thawed and the degree of discoloration of the body was observed.

From the results shown in FIG. 7, no discoloration was observed in the product Z even 24 hours after thawing. On the other hand, discoloration was observed in all the samples other than product Z from 4 hours after thawing.
That is, it was confirmed that the quality of the product Z was the best after thawing, and the quality of each of the other samples was not good.

Specimen 1 is a mackerel ML that died of natural causes and was CAS-frozen in a state of being chilled with ice CI.
Further, the sample 2 is a mackerel ML that has died of natural causes and has been CAS-frozen in a state where it has not been chilled (only put into the seawater SW).
On the other hand, the product Z is a product that has been lived, drained, chilled with slurry ice SI, and frozen by CAS.
That is, even if the sample 1 was CAS-frozen in a state where the mackerel that had died of natural causes was cooled by slurry ice SI, only CAS freezing was performed for the mackerel that died of natural causes. It was confirmed that even in the sample 2 made, discoloration of the body at the time of thawing is unavoidable. That is, the quality of each of Specimen 1 and Specimen 2 is not good.
On the other hand, Product Z is a combination of this chilling and CAS freezing, and the treatment of liveliness and blood removal.
That is, it was shown that by combining liveness, blood removal, cooling with slurry ice SI, and CAS freezing, discoloration of the body during thawing can be suppressed, so that high-quality mackerel can be obtained.

From the above results, it was shown that the frozen mackerel produced by the production method of the present invention has better quality than the frozen mackerel produced by the conventional production method.
That is, by using the production method of the present invention, it becomes possible to provide consumers with high-quality mackerel.

ML ... mackerel, MD ... mackerel, W ... raw sardine, S ... ship, CI ... ice, T ... tank, SI ... slurry ice, RE ... refrigerator, FR1・ ・ ・ CAS freezer, FR2 ・ ・ ・ Freezer

Claims (2)

In the production method of frozen mackerel
After landing the mackerel, the lively step to make the mackerel lively,
A blood draining step for draining blood from the lived mackerel,
A CAS freezing step of freezing CAS on the drained mackerel,
Production method of frozen mackerel including. The chilling step of chilling the bleeding mackerel with slurry ice is further included.
The CAS freezing step is a step of freezing the CAS with respect to the chilled mackerel.
The method for producing frozen mackerel according to claim 1.

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