JP7009112B2 - Manufacturing method of processed fish products - Google Patents

Description

Patent Law Article 30 Paragraph 2 Applicable May 10, 2017 Southwest Fisheries Co., Ltd. sells to Umeda Fisheries Co., Ltd.

Patent Law Article 30 Paragraph 2 Applicable May 13, 2017 Southwest Fisheries Co., Ltd. sells to Oita Fisheries Co., Ltd.

Patent Law Article 30 Paragraph 2 Applicable May 11, 2017 Southwest Fisheries Co., Ltd. sells to Kappou Yamashiroya

Patent Law Article 30 Paragraph 2 Applicable May 10, 2017 Southwest Fisheries Co., Ltd. sells to Kasuga Fisheries Co., Ltd.

Patent Law Article 30 Paragraph 2 Applicable April 22, 2017 Southwest Fisheries Co., Ltd. sells to Nippon Suisan Kaisha Co., Ltd.

Patent Law Article 30 Paragraph 2 Applicable May 23, 2017 Southwest Fisheries Co., Ltd. sells to Yamada Fisheries Co., Ltd.

The present invention relates to a method for producing a processed product of farmed fish.

In recent years, consumer interest in taste and safety has increased, and when eating processed fish products such as fillets or sashimi, the freshness and deliciousness of fish meat are further required. In order to meet this demand, various measures have been studied to process fish meat and deliver it to consumers after landing without impairing the freshness as much as possible.

For example, in Patent Document 1, the caught tuna is divided into live fish and dead fish, and only the live tuna is ikejime and processed into a predetermined style of meat. Discloses a method for producing high-freshness frozen tuna meat, which comprises freezing at an ultra-low temperature of about −60 ° C. and storing it in a frozen state under predetermined conditions.
In Patent Document 2, after measuring the fat content of the captured fish on board, the fish is divided into blocks, and then the fat content data is displayed on one side of the fish meat, and then the fish meat data is displayed. A tuna processing system comprising performing a labeled fish meat manufacturing process is disclosed.
In Patent Document 3, the internal organs of the tuna immediately after being picked up from the sea are removed, the tuna is immersed in a cold water tank, and the hollow of the fish from which the internal organs are taken out is cooled by injecting a water stream by a pump. The cooling method is disclosed.

On the other hand, from the viewpoint of securing fishery resources, tuna and the like are actively cultivated (including livestock, hereinafter simply referred to as aquaculture). In aquaculture, since fish are grown under controlled environment and feeding conditions, fat (fat) is carried more than natural fish, and it has become possible to provide high quality processed fish meat.

Japanese Unexamined Patent Publication No. 2002-017243 Japanese Patent Application Laid-Open No. 2003-158993 Japanese Unexamined Patent Publication No. 2005-224159

As described above, since cultured fish have a characteristic that it has a much larger amount of fat than natural fish, it is cut and processed after it has a hardness that is easy to cut. However, as time passes after landing, the freshness decreases, so that the freshness decreases from the time of processing to the time when it reaches the consumer. As a result, it is difficult to utilize the high quality of farmed fish, and there is room for improvement in order to meet the high demands of consumers for freshness and taste.
An object of the present invention is to provide a method for producing a processed product of farmed fish showing high freshness and good taste.

The present invention is as follows.
[1] The cutting process of cutting the cultivated tuna fish immediately after landing into an intermediate having a thickness of 25 cm or less using a cutting tool, and the intermediate after ikejime within 8 hours after ikejime. Obtaining a cooling step of cooling the core temperature to 10 ° C or lower, an aging step of maintaining the core temperature of the intermediate after the cooling step at 0 ° C or higher and 10 ° C or lower, and a processed product derived from the intermediate after the aging step. Processes and methods of manufacturing processed fish products, including.
[2] The production method according to [1], wherein the cooling step comprises cooling the intermediate to a core temperature of 10 ° C. or lower within 4 to 6 hours after ikejime.
[3] The production method according to [1] or [2], wherein the aging step is carried out for 3 days or more.

According to the present invention, it is possible to provide a method for producing a processed product of farmed fish showing high freshness and good taste.

FIG. 1 is a conceptual diagram showing a site for measuring core temperature. FIG. 2 is a graph showing changes in the temperature of fish meat of Example 1 and Comparative Example 1.

The method for producing a processed product of cultured fish of the present invention comprises a cutting step of dividing a cultured tuna fish immediately after landing into an intermediate having a thickness of 25 cm or less using a cutting device, and the intermediate after cutting. A cooling step of cooling the product to a core temperature of 10 ° C. or lower within 8 hours after ikejime, an aging step of maintaining the core temperature of the intermediate product after the cooling step at 0 ° C. or higher and 10 ° C. or lower, and an intermediate step after the aging step. It includes an acquisition process for obtaining a processed product derived from a product.
According to this production method, the tuna farmed fish immediately after landing is divided into intermediates of a predetermined size, cooled to a core temperature of 10 ° C or lower within 8 hours after ikejime, and then 0 ° C or higher and 10 ° C. Since the fish is kept at the following low temperature, it is possible to obtain a processed product of the farmed fish that shows high freshness and has a good taste even if the farmed fish has a lot of fat.

Further explaining this, the freshness and taste of fish meat can be judged by using the decomposition of adenosine triphosphate (ATP) as an index. That is, in fish muscle, after death, the decomposition of ATP is started by enzymes in the muscle, and ATP is adenosine diphosphate (ADP), adenosine monophosphate (AMP), inosinic acid (IMP), inosin ( It is sequentially decomposed into HxR) and hypoxanthine (Hx). Of these, IMP is known as a umami component also called inosinic acid, and it can be determined that the higher the content of IMP, the higher the freshness and the better the taste. In the present specification, ATP, ADP, AMP, IMP, HxR, and Hx may be collectively referred to as "ATP decomposition-related substance".

In the present invention, the tuna farmed fish immediately after landing, which has a lot of fat and is soft, is divided into intermediates having a thickness of 25 cm or less, so that not only is it easy to handle, but also the core is within 8 hours after ikejime. It can be reliably cooled to a temperature of 10 ° C. or lower. Rigor mortis of tuna is about 10 hours after ikejime, although there are individual differences. In the present invention, the fish body is divided into intermediates immediately before rigor mortis by allowing the core temperature to reach a core temperature of 10 ° C. or less within 8 hours after ikejime and providing a predetermined aging step. Because it cools as a fish, the decomposition of ATP in fish meat can be delayed.

In addition, since this manufacturing method includes a cooling step of cooling the core temperature to 10 ° C or less and an aging step of holding the intermediate after cooling at a temperature of 0 ° C or more and 10 ° C or less after the cooling step, the fish is refrigerated without being frozen. Maintain at. This has the advantage that it does not cause an increase in drip during thawing caused by freezing, a decrease in taste, and an increase in color change.

In the present specification, the term "process" is included in this term not only as an independent process but also as long as the intended purpose of the process is achieved even if it cannot be clearly distinguished from other processes. ..
In the present specification, the numerical range indicated by using "-" shall indicate the range including the numerical values described before and after it as the minimum value and the maximum value, respectively.
As used herein, the amount of each component in a mixture means the total amount of the plurality of substances present in the mixture when a plurality of substances corresponding to each component are present in the mixture, unless otherwise specified. ..

As used herein, the term "less than or equal to" or "less than" with respect to percentage includes 0%, ie, "not contained", unless otherwise stated, or includes values undetectable by current means. Means a range.
The method for producing the processed fish product of the present invention will be described below.

The method for manufacturing the processed product of this cultured fish is a cutting process in which the cultured tuna fish immediately after landing is divided into intermediates having a thickness of 25 cm or less, and the intermediates after cutting are divided within 8 hours after ikejime. It is necessary to include a cooling step of cooling the core temperature to 10 ° C. or lower, an aging step of maintaining the core temperature at 0 ° C. or higher and 10 ° C. or lower after cooling, and an acquisition step of obtaining a processed product derived from the intermediate after the aging step. Depending on the situation, other steps can be included.

The processed fish product obtained by this production method is a processed tuna farmed fish product.
Tuna are generally known to contain a relatively large amount of functional unsaturated fatty acids such as docosahexaenoic acid (DHA).
Examples of tuna species include tuna and Bonitos. Examples of the tuna family include the genus Tuna, the genus Auxis, the genus Mackerel tuna, and the genus Skipjack.

As used herein, the term "cultured fish" means fish that have been bred for a predetermined breeding period on compound feed, moist pellets or live food. "Aquaculture" generally means that artificial seedlings or juveniles aged 0 to 1 years of several hundred g to 5 kg are caught and bred for 3 to 5 years, and in the present specification, those having a size of 5 kg to 300 kg are further bred. It also includes "breeding" in which fish are caught and bred for a short period of time, for example, half a year to a year.

The tuna farmed fish provided for the cutting process are individuals whose weight and obesity have increased during the breeding period. The weight of the cultured tuna fish provided in the cutting step is preferably 40 kg or more, more preferably 60 kg or more, and further preferably 80 kg or more. The obesity degree of the tuna farmed fish provided in the cutting step is preferably 20 or more, more preferably 22 or more, and further preferably 24 or more. Such tuna farmed fish is a fish on which so-called fat (Toro) is abundantly contained in the whole individual, and has high commercial value when made into a processed product, and is preferable as a food. As used herein, "classification of obesity" means a value calculated from the total body weight and fork length of a farmed tuna fish according to the following formula.
{Total weight (g) / [Caudal ramus length (cm)] ³ } x 1000

In the cutting step, the cultured tuna fish immediately after landing is cut into intermediates having a thickness of 25 cm or less using a cutting tool.
When landing, the fish are paralyzed by the commonly used method. Any method may be used for paralysis, and for example, carbon dioxide gas, cold water immersion, electric shocker, or the like can be applied. Of these, it is preferable to apply an electric shocker because it is possible to avoid excessive muscle movement during landing and suppress the generation of so-called burnt meat. “Immediately after landing” means within 5 minutes, preferably within 2 minutes after landing. Ikejime is performed at the time of landing. The term "ikejime" as used herein means a process of paralyzing the tuna (live fish) taken up to bring them into a state of brain death and then further draining blood.

Then, the individual after ikejime is divided. By cutting, an intermediate having a thickness of 25 cm or less can be obtained. As used herein, the term "intermediate" means a portion cut out as a part of an individual of cultured tuna fish. The shape of the intermediate is not particularly limited as long as it has a thickness of 25 cm or less. The intermediates include those in a form obtained by customary deciding (hereinafter, customary processing form). By convention, the usual morning sickness is to first make a so-called "GG" with the gills and internal organs removed, and then cut off the head and tail from the GG to create a "dress (also called headless)" or dress. It is divided into three pieces, the "fillet" with the spine removed, and the "loin", which is the fillet divided into male and female sections, in this order. The intermediates herein also include "blocks" (also referred to as rollers) obtained by further cutting the loin into, for example, two to four pieces in a direction perpendicular to the longitudinal direction of the body. Further, the intermediates in the present specification also include intermediates having a shape different from those of customary processing forms, which are parts of individual fish. There is no particular limitation on the shape of the intermediate having a shape different from that of the customary processing form, and the shape is derived by further removing a part of the customary processing form, and is cut out from the individual fish without depending on the customary processing form. It may have any shape.

The thickness of the intermediate product obtained in the cutting step is 25 cm or less, preferably 23 cm or less. By setting the thickness of the intermediate to a thickness within this range, it is possible to efficiently and surely cool to the target core temperature in the subsequent cooling step. The lower limit of the thickness of the intermediate material varies depending on the state of the individual fish after landing, but may be, for example, 10 cm or 15 cm.

As used herein, the term "thickness of an intermediate" means the distance from the bottom of the portion that is at the highest position when a specific surface of the intermediate is placed as the bottom.
When measuring the thickness of an intermediate, place the intermediate on a mounting table with a flat mounting surface. At this time, the posture in which the intermediate can be stably maintained without falling is set as the reference posture. If the bottom surface is curved or uneven, the intermediate material is lightly pressed against the mounting surface so that the entire surface of the bottom surface is in contact with the mounting surface as much as possible. However, when the intermediate is pressed against the mounting surface, the intermediate is pressed so that the thickness does not significantly change from the actual thickness as a result of excessive pressing in the thickness direction.
Regarding the identification of the bottom surface of the intermediate material, the surface having the largest surface area among the surfaces along the longitudinal direction of the intermediate material is defined as the bottom surface. When determining the surface with the largest surface area, the fine irregularities provided on the surface are not taken into consideration, and when an intermediate is placed on the mounting surface, each surface is compared as a plane facing the mounting surface. And decide. For those having a lenticel on one surface along the longitudinal direction of the intermediate, the surface having the lenticel may be the bottom surface.

As the intermediate, the maximum thickness of the intermediate is 25 cm or less, and the portion of the intermediate is 1/2 or more, more preferably 2/3 or more, still more preferably 3/4 or more of the length in the longitudinal direction of the intermediate. The thickness is preferably 10 cm or more. With an intermediate having such a shape, the temperature of the intermediate can be easily controlled. As a result, in the cooling step described later, it is possible to efficiently and surely cool to the target core temperature while avoiding the risk of freezing.

The length (distance in the longitudinal direction) and width (distance in the direction perpendicular to the longitudinal direction in a plan view) of the intermediate are not particularly limited, and for example, the size of the loin is generally 65 cm to 90 cm in length. Those having a width of 25 cm to 35 cm can be mentioned.

For the cutting, a cutting tool capable of cutting individual fish to a predetermined size may be used. Preferably, the cutting tool is a relatively short kitchen knife having a blade length of 50 cm or less, for example, 20 cm or more and less than 30 cm, and more preferably 20 cm or more and 28 cm or less. By using such a cutting tool, it is possible to reliably cut the fish immediately after landing. In particular, since farmed fish have a lot of fat, they are soft immediately after landing, and it is difficult to cut them reliably and efficiently with a knife with a long blade, which is usually used for cutting. In this respect, by using a knife with a short blade length, even a farmed fish with a lot of fat can be cut reliably and efficiently. The cutting tool is not limited to a kitchen knife, and may be a cutter, a knife, a cutting machine, or the like having the above-mentioned blade length. Further, if an intermediate having the desired thickness can be obtained, a cutting tool to be used in the whole or a part of the cutting process can be appropriately selected.

Further, it is preferable to tilt the blade portion of the cutting tool with respect to the surface of the fish body for cutting. The angle between the blade of the cutting tool and the fish body at this time is preferably 45 ° or less, more preferably 40 ° or less, and further preferably 10 to 30 ° with respect to the surface of the fish body. preferable. By setting the angle between the blade and the fish in such a range, even the fish immediately after landing can be separated more reliably. For example, when inserting knives on both sides of the center line on the back side of the dress, the angle of the blade of the knives with respect to the fish is 45 ° or less, preferably 40 ° or less, more preferably 10 to 10 while firmly fixing the fish body. At 30 °, you can insert the knife until you can see the nerve spines.

The angle between the blade of the cutting tool and the fish when cutting is the surface of the blade facing the fish when the blade is tilted and the blade is brought into contact with the fish, and the fish. Specified as the angle formed with the surface of the. The angle between the blade of the cutting tool and the fish body can be specified from, for example, a photograph taken from the side at the time of cutting and the obtained photographic image. When the surface of the fish body in contact with the blade portion is curved, the tangent line at the contact point between the blade portion and the fish body is obtained and specified as the angle between the tangent line and the blade portion.
At the time of cutting, it is more preferable to firmly fix the fish body. As the fixing method, there is no particular limitation on the method of holding the fish body by personnel or by using a fixing device. The fixing method can be appropriately selected in consideration of the size, efficiency and the like of the fish.
Regarding the angle between the blade of the cutting tool and the fish body when cutting, and the cutting method, the target was explained as a fish body, but the fish body here refers to the individual fish itself and the process of cutting. Both pieces of the resulting individual fish are included.

The slicing step preferably further comprises trimming the intermediates obtained by slicing. As a result, the shape of the intermediate can be adjusted to improve efficiency in the subsequent processing, and pinholes and the like in the storage bag can be eliminated in the cooling step and the aging step after the splitting step. For trimming, any instrument that can adjust the shape of the intermediate can be used without limitation. As such a trimming tool, a cutting tool, scissors or the like used at the time of cutting can be used.

In trimming, although it depends on the type of trimming tool, in general, the angle of the blade with respect to the body is tilted to an angle almost parallel to the body, for example, 10 ° or less, preferably 5 ° or less, and the trimming tool is used to sharpen thinly. It is preferable to use. As a result, even if the intermediate has high elasticity, trimming can be performed efficiently and reliably.

In the cooling step, the intermediate after cutting is cooled to a core temperature of 10 ° C. or less within 8 hours after ikejime. In other words, it is known that the muscles of the fish at the time of ikejime have a core temperature of about 30 ° C. Therefore, the core temperature of the fish at the time of ikejime should be 10 ° C or less within 8 hours after the ikejime. Ikejime.

In the present specification, the "cooling step" means a step until the core temperature becomes 10 ° C. or lower. The core temperature is the temperature of the portion corresponding to the central portion of the intermediate, and can be, for example, the temperature of the boundary between the bloody muscle and the normal muscle (see FIG. 1). At the time of measurement, as shown in FIG. 1, a thermometer A may be inserted between the blood line muscle 10 and the normal muscle 12 for measurement. The measurement is not particularly limited as long as the inside of the fish meat can be measured. For example, a wire-shaped thermometer (Custom Co., Ltd., waterproof digital thermometer CT-310WP) or a data logger (KN Laboratories Co., Ltd., Thermocron G type) can be used. By measuring the temperature of this site, it is determined that the entire intermediate is at the specified temperature. In the cooling step, the first measurement is carried out 30 to about 60 minutes after the start of cooling, and then the measurement is carried out every 15 to 30 minutes, and the measurement is terminated when 10 ° C. or lower is confirmed.

The time until the core temperature becomes 10 ° C. or less is within 8 hours after ikejime. Within 8 hours after ikejime, the splitting and cooling can be reliably completed before rigor mortis begins. As a result, the decomposition of ATP in muscle can be delayed, and a processed product with high freshness can be provided. The time until the core temperature becomes 10 ° C. or lower is preferably 7 hours or less, and more preferably 6 hours or less. The minimum time required for the core temperature to reach 10 ° C. or lower is not particularly limited, but it is preferably adjusted within a range in which the intermediate does not freeze. The time for reaching the core temperature of 10 ° C. or lower is preferably 4 to 6 hours after ikejime, for example, from the viewpoint of freezing prevention and efficiency.

As long as the temperature of 10 ° C. or lower can be reached within 8 hours, there is no particular limitation on the cooling method. From the viewpoint of ease of transition to the aging process in the subsequent stage, prevention of freezing, etc., immersion in cold water having a water temperature of 0 ± 2 ° C., for example, ice water can be mentioned. By immersing in such ice water, the core temperature lowering rate becomes about 10 to 5 ° C. per hour. When soaking in ice water, the intermediate may be contained in a bag or the like. The size, shape and material of the bag containing the intermediate can be appropriately selected as long as the cooling effect is not impaired, such as a polyethylene bag. In order to prevent the infiltration of cooling water due to pinholes, a thickness of about 0.05 mm to 0.1 mm can be used.

In the aging step, the core temperature of the intermediate after the cooling step is maintained at 0 ° C. or higher and 10 ° C. or lower. By setting the holding temperature to 0 ° C. or higher and 10 ° C. or lower, ATP decomposition in the intermediate can proceed slowly.
That is, since the aging process is started as early as 8 hours after ikejime, not only the content of AMP in the muscle can be increased at the start of the aging process, but also the decomposition rate of AMP at the very initial stage can be reduced. Can be slowed down. Therefore, the rate of decomposition of AMP and the subsequent production and decomposition of ATP decomposition-related substances are adjusted according to the holding conditions in the aging step, so that the content of IMP in fish meat is in a high range at the time of desired shipment. It is possible to set to.

The holding conditions include holding time, holding temperature, and the like. The retention time can be 3 days or more, 4 days or more, 5 days or more, 6 days or more, or 7 days or more from the viewpoint of adjusting the content of ATP decomposition-related substances in fish meat, and the upper limit of the retention time. The value can be 10 days or less in terms of the content of residual IMP. The holding time is more preferably 7 days or more and 8 days or less.

The core temperature of the intermediate product at the start of the aging process is the core temperature at the end of the cooling process. The core temperature after the start of aging may be 10 ° C. or lower, preferably 4 ° C. or lower, and more preferably 3 ° C. or lower. The lower limit of the core temperature in the aging step may be any temperature as long as the intermediate to be cooled does not freeze, and may be, for example, 1 to 3 ° C.

During the aging process, the fish meat may be protected by a protective member. Examples of such a protective member include water-absorbing paper for suppressing a decrease in the water content in fish meat.

In this manufacturing method, after the aging process, the intermediate product after aging is further divided into a desired size as a processed product, and during or after the aging process, the processed product is transported to a desired consumption area. It can include steps and the like. The order of these optional steps is not particularly limited if possible.

In the acquisition step, after the aging step, a processed product derived from the intermediate is obtained. The processed product obtained in the acquisition step is obtained by advancing the decomposition of ATP in the fish meat through the aging step and adjusting the content or the content ratio of the umami component in the fish meat in the tuna farmed fish. Therefore, the processed product can exhibit good taste while exhibiting high freshness. The processed product obtained in the acquisition process is not particularly limited in form as long as it is derived from the intermediate product used in the aging process. It may be a small piece cut into small pieces. The acquisition process means a stage in which the aging process is completed and the product is shipped, and may be at the time of shipment.

The high freshness and good taste of processed products are determined by methods known in the art, such as the content of ATP decomposition-related substances, the content of lactic acid, the content of free amino acids, the freshness K value, and the a * value on a color difference meter. , The evaluation can be made based on one or more indexes appropriately selected from the pH of the processed product and the like.

The content of ATP decomposition-related substances is measured by liquid chromatography using 1260 Infinity manufactured by Agilent Technologies. For the column, "InterSustain (registered trademark) AQ-C18 (3 μm, 3.0 x 150 mm) manufactured by GL Science Co., Ltd. is used. After applying the sample to the column, 50 mM triethylamine (TEA) (pH 5.0, H ₃ PO ₄ ) is used. ): Elute from the column with methanol (95: 5) (v / v) to detect and quantify ATP degradation-related substances at a measurement wavelength of 260 nm.

The evaluation can be performed, for example, based on the content of IMP among the ATP decomposition-related substances. It can be evaluated that the higher the content of IMP, the better the taste.
It can also be evaluated based on the ratio of the total content of two or more ATP decomposition-related substances to the content of IMP. For example, the higher the ratio of the content of IMP to the total content of ATP, ADP, AMP, IMP, HxR and Hx, the better the taste can be evaluated.
As another example, it can be evaluated that the lower the ratio of the total content of HxR and Hx to the total content of ATP, ADP, AMP and IMP, the better the freshness. In this case, it can be 50% or more, preferably 60% or more, and more preferably 70% or more on a weight basis.

The freshness K value is an index expressed by the following formula, and is a numerical value of the freshness determination evaluation by measuring the progress of decomposition of ATP.
K value = (HxR + Hx) / (ATP + ADP + AMP + IMP + HxR + Hx) x 100
The smaller the K value, the smaller the ratio of the total amount of HxR and Hx to the total amount of ATP and ATP decomposition-related substances, and the decomposition from IMP to HxR or Hx has not progressed sufficiently, that is, This means that a large amount of ATP decomposition-related substances up to IMP remains. The K value of the processed product obtained by this method can be 35% or less, preferably 15% or less, and more preferably 10% or less.

The processed fish product obtained by the production method of the present invention is rich in fat (toro) peculiar to farmed fish and has a good taste, and can be used as a food with high commercial value showing high freshness. can.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the present invention is not limited thereto. Unless otherwise specified, "%" is based on mass.

[Example 1]
(1) Breeding of tuna 1500 tuna with a body weight of about 3 kg and a fork length of about 55 cm were housed in a 40 m × 45 m abalone cage, and breeding was started. Mackerel and sardines were used as feeds, and they were usually fed once a day and once every two days in winter. The breeding started in July and was carried out for more than 3 years, paralyzed by electricity and landed. Immediately after landing, blood was removed, squeezed, and the fins and internal organs were removed by the usual method to obtain tuna GG. The weight of the obtained tuna GG was 80 kg or more, and the obesity degree was 24 or more.

(2) Cutting The cutting was carried out in a cutting room at room temperature of 18 to 20 ° C. For the cutting board, I chose one that is said to be non-slippery. Regarding the fixing of the fish body, it was only held by hand, and no fixing device was used. The worker wore vinyl gloves on both hands, and also wore cut-resistant gloves on the hand without the kitchen knife.
Using a knife with a blade length of 20 to 28 cm, the head and tail were cut off from the GG of the tuna, and then the knife was put on the dorsal side and then the ventral side according to the usual procedure, and the fish meat was cut into loins.
In the cutting process, when first inserting knives on both sides of the back center line of GG, cut the surface to a depth of several mm, and then make the blade of the knife about 10 to 30 ° to the fish body. At an angle, I carefully cut it with a blade until I could see the nerve spines. Also, when carving, I picked it up lightly so that I couldn't avoid it, and proceeded with the process carefully. The ventral side was also cut in the same way. Since it is within a few hours after landing, the body is elastic, but by carefully slicing with a relatively short knife, we were able to reliably obtain each of the four loins.

Then, trimming was also performed to adjust the shape of the loin. At the time of trimming, the knife was operated so as to scrape the knife at 5 ° or less, which is almost parallel to the body.

As described above, loin was obtained 3 hours after ikejime. The length of the loin was 65 cm to 90 cm, and the thickness was 15 cm to 23 cm when measured with the lenticel down.

(3) Cooling and aging The loin obtained in (2) above is wrapped in water-absorbent paper and then directly stored in a plastic bag, and placed in a 500 L polyethylene container box containing ice water (water temperature 0 ° C ± 2 ° C). , The whole loin was submerged so that the whole was in ice water. After that, check the temperature of ice water as appropriate, adjust the water temperature to the range of 0 ° C ± 2 ° C, cool the loin while measuring the core temperature as described later, and mature after it falls below 10 ° C. Was done.

[Comparative Example 1]
The tuna bred under the same conditions as the tuna used in Example 1 were landed and then stored in ice water for 2 days in the state of GG while measuring the core temperature in the same manner as in Example 1. The GG after storage was cut 52 hours after ikejime using a normally used kitchen knife (blade length 30 cm). I broke it with a blade against my body and got four loins. The length of the loin was 65 cm to 90 cm, and the thickness was 15 cm to 23 cm when measured with the lenticel down.

[evaluation]
(1) Core temperature measurement The core temperature was measured every 15 minutes to 1 hour. In the case of loin, a thermometer (manufactured by Custom Co., Ltd., waterproof digital thermometer CT-310WP) was inserted into the boundary between the blood line muscle and the normal muscle around the center of the loin for measurement (see FIG. 1). In the case of GG, a data logger (Cermocron G type manufactured by KN Laboratories Co., Ltd.) was installed at the part where a notch was made for blood removal at the time of landing (at the base of the pectoral fin, around the center of the body). The core temperature was measured as shown in Table 1 and continued up to 52 hours after ikejime.
The results are shown in Table 1 and FIG. In FIG. 2, white circles indicate Example 1 and black circles indicate Comparative Example 1. At the time of division, white triangles (Example 1) and black triangles (Comparative Example 1) are shown. Arrows indicate the approximate timing of rigor mortis.

(2) Content of ATP decomposition-related substances The freshness of the fish meat of Example 1 and Comparative Example 1 was evaluated as follows based on the contents of ATP and ATP decomposition-related substances.
The content of the ATP decomposition-related substance was measured by liquid chromatography by 1260 Infinity manufactured by Agilent Technology, and "InterSustain (registered trademark) AQ-C18 (3 μm, 3.0 x 150 mm) manufactured by GL Science was used as the column. After applying the sample to the column, elution from the column with 50 mM triethylamine (TEA) (pH 5.0, H ₃ PO ₄ ): methanol (95: 5) (v / v) was performed and ATP degradation was performed at a measurement wavelength of 260 nm. Related substances were detected and quantified. The results are shown in Table 2.

As shown in Table 1 and FIG. 2, in Example 1 in which the cutting was performed 3 hours after ikejime, the core temperature of the obtained loin fell below 10 ° C. 4 hours after ikejime, and then 2 It was kept at about ℃ (aging). As shown in Table 2, a large amount of ATP remains in the fish meat 1 hour after the cutting in Example 1, and even if it is 48 hours after the cutting (52 hours after the ikejime), the IMP The content was as high as 10 μmol / g or more. The IMP was 10.38 μmol / g even at 76 hours after ikejime.

On the other hand, in Comparative Example 1, the core temperature of the fish fell below 10 ° C. 10 hours after landing (stored in GG), and rigor mortis started at this point.
In Comparative Example 1, in which the fish was cut 52 hours after ikejime (core temperature 2 ° C), the fish meat (flesh) was moderately hard at the time of cutting and could be easily cut with a kitchen knife. As shown in, IMP was already the main ATP decomposition-related substance in fish meat at the time of ikejime. The content of IMP is 9.71 μmol / g 24 hours after ikejime (76 hours after ikejime) and 9.03 μmol / g 48 hours after ikejime (100 hours after ikejime). It can be seen that the decomposition of IMP has started, which is even lower than that at the time of ikejime. Moreover, even 48 hours after the same division as in Example 1, the content of IMP was lower than that in Example 1.

When the fish meat of Example 1 and Comparative Example 1 were eaten for 76 hours after ikejime, the processed product of Example 1 having a high IMP content was clearly more delicious. After that, when the processed product obtained in the aging period of 7 to 8 days was eaten by continuing the aging as it was, the processed product of Example 1 was more delicious.

As described above, according to the present invention, it is possible to obtain a processed tuna farmed fish product which is rich in fat, exhibits high freshness, and has a good taste.

Claims (6)

A cutting process that cuts the tuna farmed fish immediately after landing into an intermediate with a thickness of 25 cm or less using a cutting tool.
A cooling step that cools the intermediate after cutting to a core temperature of 10 ° C or less within 8 hours after ikejime.
The aging process that keeps the core temperature of the intermediate after the cooling process at 0 ° C or higher and 10 ° C or lower, and
After the aging process, the acquisition process to obtain the processed product derived from the intermediate, and the acquisition process.
How to make processed fish products, including. The production method according to claim 1, wherein the cooling step comprises cooling the intermediate to a core temperature of 10 ° C. or lower within 4 to 6 hours after ikejime. The manufacturing method according to claim 1 or 2, wherein the aging step is carried out for 3 days or more. The production method according to any one of claims 1 to 3, wherein the content of the intermediate inosinic acid is 10 μmol / g or more in 52 hours after ikejime. The production method according to any one of claims 1 to 4, wherein an electric shocker is used for ikejime of the tuna farmed fish. The production method according to any one of claims 1 to 5, wherein the tuna farmed fish is ikejime within 5 minutes after landing.

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