JP2004208697A - Cooked shrimp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooked shrimp having the same flavor as that of fresh shrimp even after long term preservation, and also difficult to cause deterioration even when subjected to freezing or thawing. <P>SOLUTION: This cooked shrimp is obtained through the following process: making fresh shrimp having vital reaction in tail part muscle come into contact with 85-98°C hot water, and cooling just after passing a time required for longitudinally crushing strength of a sample picked from the shrimp tale muscle and having 5±0.2 mm thickness detected by a parallel plate-type pressure testing machine at a room temperature to be 15-30 N per 1 cm<SP>2</SP>of the cross-sectional area of the sample followed by immediately cooling the sample. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a heat-treated shrimp, and more particularly, to a novel heat-treated shrimp in which the deterioration of the original taste and texture of fresh shrimp is suppressed by altering the protein component of the fresh shrimp. .

  In general, crustaceans such as shrimps and crabs in fish and shellfish are stiff after death due to the cessation of life reactions after death, followed by oxidation of tissues, browning due to the generation of hydrogen sulfide, and further softening. A phenomenon that leads to decay is seen. In order to delay or prevent the occurrence of such an undesirable deterioration phenomenon in foods, a method of storing frozen foods is generally adopted. However, when eating shrimp, especially shrimp and cherry shrimp, raw (raw) shrimp, after thawing, a part of the bound water contained in the muscular tissue of the shrimp flows out relatively quickly as a drip. For this reason, freezing is not considered to be an appropriate method for preventing the deterioration of taste because the muscle tissue is softened and the taste is lost.

  In addition, there is no effective way to prevent the deterioration of the taste even when raw shrimp such as sweet shrimp are refrigerated and eaten before decay. When the shrimp is heated to fix the bound water to the cell tissue, the quality of the raw shrimp is deteriorated and the flavor is impaired, so that the preservation management of the raw shrimp has been extremely difficult. .

  Under the circumstances as described above, the appearance of a method capable of maintaining the freshness and taste of freshly caught shrimp for a long time has been awaited.

  Therefore, the present invention aims at preserving the flavor of fresh shrimp without deteriorating over a long period of time, maintaining the same flavor as fresh shrimp even after long-term storage, and furthermore, freezing and thawing As a result of conducting various studies to obtain shrimp that is hardly deteriorated even after the treatment, it was found that heat treatment of fresh shrimp under specific conditions is effective. Therefore, by utilizing this new technology, a heat-treated shrimp having a novel performance is provided.

The heat-treated shrimp of the present invention, which can solve the above-mentioned problems, makes fresh shrimp, which maintains a state of living reaction, exposed to hot water of 85 to 98 ° C. and is parallel to the shrimp's tail muscle in the lateral direction. The vertical crushing strength of a sample having a thickness of 5 ± 0.2 mm cut and collected at room temperature by a parallel plate type pressure tester is in the range of 15 to 30 N per 1 cm ² of the cross-sectional area of the sample. It is characterized by cooling immediately after the necessary time has elapsed.

  In producing the heat-treated shrimp of the present invention, the fresh shrimp as a raw material is most preferably in a state of being captured, that is, alive, but is in a dormant state if it maintains a state of living response. It may be one that has been rapidly frozen immediately after its capture, or one that has just been removed from its head or shell, that is, a state that can be moved by stimulation. Then, it is important to start the heat treatment when there is a life reaction of the fresh shrimp or when the life reaction has just stopped and the deterioration has not started. Further, for this heat treatment, it is preferable to use hot water having a temperature of 85 ° C. or higher and up to 98 ° C. as described above, and the hot water used at that time may be fresh water, for example, an aqueous solution containing salts such as seawater. There may be.

  Further, the step of cooling when producing the heat-treated shrimp of the present invention preferably includes a cooling step using cold water of 30 ° C. or less, particularly 25 ° C. or less, and furthermore, primary cooling in contact with warm water of 50 ° C. or less. It is more preferable to include a step and a secondary cooling step of contacting with cold water of 30 ° C. or lower. Further, a freezing step can be included as a final stage of such a cooling step.

  Hereinafter, a method for producing a heat-treated shrimp according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view of an apparatus for heat-treating shrimp after being carried in by the carry-in conveyor C1, and after heating and cooling are finished and carried out again by the carry-out conveyor C2. Here, the heat treatment apparatus D includes a weighing unit 1, a heating unit 2, a first cooling unit 3, and a second cooling unit 4, and the end of the carry-in conveyor C1 faces above the weighing unit 1.

  The weighing section 1 is provided with an automatic weighing machine 14, and a basket H <b> 1 made of a container with numerous small holes that does not spill the shrimp a is placed on the automatic weighing machine 14. And receive the live shrimp a sent by the carry-in conveyor C1. The basket H1 is not limited to the one having the above structure, but may be a stainless steel wire mesh, and any basket having the same function may be used.

  A frame 10 is erected between the weighing unit 1 and the heating unit 2, and a basket driving unit 11 is installed on the frame 10. The basket drive unit 11 includes a rotating shaft 12 fixed horizontally to the frame 10 and an arm 13 driven to rotate by the rotating shaft 12. Holds the basket H1. Then, when the drive source (not shown) is turned on, it rotates about 120 degrees as shown by the chain line in the figure, and the shrimp a in the basket H1 can be put into the heating unit 2. ing.

  On the other hand, the heating unit 2 includes a water tank 24 for supplying hot water, a steam pipe 25 for supplying steam to the water tank 24, a circulation pipe 26 having both ends opened to the water tank 24, and a middle part of the circulation pipe 26. And a circulating pump 27 provided. The hot water may be fresh water or salt water, and is heated to 85 ° C. to 98 ° C. by blowing steam, and is circulated by the circulation pump 27 so that the temperature of the hot water in the water tank 24 becomes uniform. In such a water tank 24, a basket H2 having the same structure as the basket H1 is disposed, and can receive the live shrimp a inserted by the basket H1.

  A frame 20 stands between the heating unit 2 and the first cooling unit 3, and a basket driving unit 21 is installed on the frame 20. The basket driving unit 21 includes a rotation shaft 22 fixed horizontally to the frame 20 and an arm 23 driven to rotate by the rotation shaft 22. Holds the basket H2. Then, when a drive source (not shown) is turned on, the shrimp rotates about 120 degrees as shown by a chain line in the figure, and the shrimp in the basket H2 can be put into the first cooling unit 3. ing.

  The first cooling unit 3 includes a water tank 34 for holding hot water for cooling, a circulation pipe 35 having both ends opened in the water tank 34, and a circulation pump 36 provided in the middle of the circulation pipe 35. . The warm water may be fresh water or salt water, and natural seawater may also be used. When natural seawater is used as the hot water, a seawater supply pipe is provided to supply the natural seawater to the water tank 34, and excess seawater is externally discharged by a pump 38 via a discharge pipe 37 connected to the bottom. It is configured to discharge. A basket H3 having the same structure as the basket H1 is disposed in the water tank 34 so that the shrimp thrown in by the basket H2 can be received.

  A frame 30 is provided upright between the first cooling unit 3 and the second cooling unit 4, and a basket driving unit 31 is provided on the frame 30. The basket driving unit 31 includes a rotating shaft 32 fixed horizontally to the frame 30 and an arm 33 driven to rotate by the rotating shaft 32. Holds the basket H3. Then, when a drive source (not shown) is turned on, the shrimp in the basket H3 can be turned into the second cooling unit 4 by rotating about 120 degrees as shown by a chain line in the figure. ing.

  The second cooling unit 4 includes a water tank 41 for storing cold water for finally cooling the treated shrimp, and the water tank 41 is formed larger than the water tank 34 of the first cooling unit 3. The cold water in the water tank 41 may be fresh water or salt water, and natural seawater may be used. When natural seawater is used as the cold water, natural seawater at a normal temperature, preferably low-temperature natural water pumped from the middle or deep sea level, is preferably supplied to the water tank 41 via a seawater supply pipe. Further, a blower F1 is provided above the water tank 41, and an end of the carry-out conveyor C2 faces the vicinity of the water tank 41, and the processed shrimp sent out from the water tank 41 by scooping with cold water or the like. At the same time, it is placed on the unloading conveyor C2 to separate the water, and at the same time, it is possible to remove the water to the freezing room (not shown) while removing excess water with the blower F2.

  In the above apparatus, the hot water to be put into the water tank 24 of the heating unit 2 may be, for example, a 1 to 3% aqueous solution of salt, or may contain an amino acid salt in some cases. The temperature of the hot water must be 85 ° C. or higher in order to efficiently modify proteins and the like contained in the muscle tissue of shrimp, but is preferably 90 ° C. or higher, and more preferably 95 ° C. or higher. For example, during the heat treatment of the shrimp, it is desirable to adjust the temperature of the hot water to be in the range of 90 to 98 ° C.

In the heat treatment of the shrimp, the contact time between the heating medium such as hot water and the shrimp depends on the type and temperature of the heating medium, the size of the shrimp, the ratio of the amount of the heating medium to the amount of the shrimp, and the like. It is necessary to adjust appropriately. In particular, the longitudinal crush strength of a 5 ± 0.2 mm thick sample taken at room temperature by a parallel plate press at room temperature was obtained by cutting the shrimp tail muscle after heat treatment in parallel with the transverse direction. It is preferable that the sample be brought into contact with the sample within a time period required to reach 15 to 30 N per 1 cm ² of the cross-sectional area of the sample. Such contact time is usually between about 1 minute and 5 minutes, and is preferably selected so that the temperature of the shrimp muscle tissue reaches at least 70-75 ° C.

  The shrimp thus heat-treated is immediately cooled by cold water of 30 ° C. or less. In the cooling step, the temperature of the muscle tissue of the shrimp quickly falls to 65 ° C. or less, preferably 55 ° C. or less, and the muscle tissue is unnecessarily increased. It is desirable that the reforming of the steel does not proceed. However, for preservation of the heat-treated shrimp, it is preferable to cool it further completely. Therefore, the temperature of the cold water is preferably 25 ° C. or less, more preferably 20 ° C. or less, and may be 10 ° C. or less. Then, when completely cooled and then frozen, the properties of the modified muscle tissue can be maintained for a longer period of time.

  Further, in order to further enhance the cooling efficiency with the cold water of 30 ° C. or less, the first cooling step of bringing the shrimp subjected to the heat treatment with the hot water into contact with warm water of 50 ° C. or less provides a primary cooling step of improving the muscle tissue. After the progress is stopped, if cooling is performed in two stages by a secondary cooling step of contacting with cold water of 30 ° C. or less, low-temperature cold water can be effectively used, and cooling can be performed more efficiently. .

The heat-treated shrimp of the present invention thus produced has a thickness obtained by contacting fresh shrimp having a life reaction with hot water of 85 ° C. to 98 ° C. and cutting the tail shrimp in parallel in the lateral direction. A sample of 5 ± 0.2 mm is heat-treated so that the longitudinal crush strength at room temperature by a parallel plate type pressure tester is in the range of 15 to 30 N per 1 cm ^{2 of} cross-sectional area. The shrimp is similar to a fresh shrimp even after being frozen or thawed, so that the muscle tissue is modified so that the taste and texture are not easily deteriorated while at the same time exhibiting a good taste and excellent texture. The effect is obtained that the time during which the taste is maintained without deterioration can be greatly extended.

  On the other hand, if the raw (raw) shrimp, which has started to deteriorate, is used instead of the shrimp that is being used as a raw material for the heat-treated shrimp, the muscular tissue of the shrimp has already undergone stiffness after death, and the softening deterioration has progressed. Even if it tries to improve the preservability by heat treatment, it becomes a boiled shrimp with a completely different taste and texture from the flavor of fresh shrimp, and a mellow taste like the heat-treated shrimp of the present invention cannot be obtained. .

  Hereinafter, an example of producing a heat-treated shrimp from fresh sweet shrimp by carrying out the method for producing a heat-treated shrimp of the present invention using an apparatus having the above-described configuration and installed on an industrial ship will be described.

  The sweet shrimp inhabit the seabed 300 to 500 m below the surface of the water, and the low-temperature seabed of 10 ° C. or lower is routed by a trawl net for an average of about 3 hours and 30 minutes to capture the sweet shrimp. The net is then pulled up on the deck of the ship and the shrimp are placed in the fish tank of the ship. The shrimp swim alive in a metal fish tank filled with natural seawater at 2 ° C to 10 ° C. In.

  After these sweet prawns are scooped out of the fish basin, other bycatch fish are manually removed from the sweet prawns by primary sorting. This is followed by a second sorting by an automatic sorter for sorting by grade and size. The thus-selected live sweet shrimp are immediately placed on the automatic carry-in conveyor C1, and are carried into the heat treatment apparatus D in the same form, or after taking the head or removing the shell.

  First, live sweet prawns successively carried in by the carry-in conveyor C1 are put into a basket H1 placed on the automatic weighing machine 14 of the measuring section 1, and when the active sweet prawns reach a predetermined amount, the carry-in conveyor C1 is removed. Stop. Simultaneously, the switch of the basket driving unit 11 is turned on, and the basket H1 is rotated about 120 degrees, so that the live sweet shrimp is put into the basket H2 placed in the water tank 24 of the heating unit 2.

  The water tank 24 is filled with hot water such as 1% to 3% saline solution, which is set at a temperature of 85 ° C. to 98 ° C. When the heat treatment is performed for a period of seconds to 10 minutes, preferably for about 1 to 3 minutes, irreversible changes occur in the muscle tissue of the activated shrimp, and it becomes difficult for tissue-bound water to be released. Then, when the switch (not shown) of the basket drive unit 21 is turned on, the arm 23 is operated to rotate the basket H2 in the water tank 24 to the position indicated by the dotted line in the figure and hold the basket H2 inside the basket H2. The processed sweet shrimp is put into a basket H3 placed in a water tank 34 of the primary cooling unit 3.

  The water tank 34 is filled with warm water, such as natural seawater, set at a temperature of 45 ° C. to 50 ° C., and the treated sweet shrimp placed in the basket H3 is immersed in the warm water for at least 30 seconds. Then, the heat treatment of the muscle tissue of the processed sweet shrimp stops any further changes. Thereafter, when the switch (not shown) of the basket driving unit 31 is turned on, the arm 33 is operated, and the basket H3 in the water tank 34 is rotated to a position indicated by a dotted line in the figure, and is held inside the basket H3. The treated sweet shrimp is thrown into the water tank 41 of the secondary cooling unit 4 while removing moisture with the blower F1.

  The water tank 41 is filled with cold water maintained at 1 ° C. to 23 ° C., for example, salt water such as natural seawater or low-concentration saline, mineral water, clear water, and the like. Let cool for 2 seconds. The cooled sweet shrimp thus cooled are scooped up one by one on a carry-out conveyor C2, and transported to a freezing room (not shown) while separating attached water and removing excess water by a blower F2.

  The heat-treated sweet shrimp, which is appropriately divided and frozen as needed, is further packaged in a box or the like, and stored as a product, for example, in a freezer at −20 ° C.

(First embodiment)
After scavenging, the active sweet shrimp A0 sorted to a size of 90 to 120 per kg after scooping was scooped up from the water tank, immediately put into a 2% saline solution at 95 ° C, and heat-treated for about 2 minutes until the muscle temperature reached 71 ° C. Immediately after scooping, it is thrown into seawater at 10 ° C. and cooled, but the muscle of the shrimp loses transparency at this stage and becomes cloudy or white. The shrimp thus treated was further dehydrated and then rapidly frozen at -20 ° C or lower to produce the heat-treated sweet shrimp B1 of the present invention.

The heat-treated sweet shrimp B1 (frozen product) thus obtained is put in a bag made of a polyethylene film together with water, immersed in running water at 5 to 10 ° C. for about 10 minutes, half-thawed, and the shell of the shrimp is peeled off. Immediately after the thaw was completely thawed, the second node of the tail muscle was cut in a direction substantially perpendicular to the axis to prepare a muscle sample having a thickness of 5 ± 0.2 mm and its diameter was measured. Subsequently, the muscle sample was sandwiched between parallel plate-type pressurizing testers (San Kagaku, COMPAC-100, using a disk adapter), and the maximum load value during crushing in the vertical direction until the thickness became 50% ( N) was determined, the longitudinal crush strength (N / cm ² ) per 1 cm ² of the cross-sectional area of the muscle sample was calculated, and the average value of the crush strength obtained for the 10 muscle samples was calculated. Table 1 shows the processing conditions of the shrimp and the test results.

  Thaw heat-treated sweet shrimp B1 (frozen product) in the same manner as above, store it in a refrigerator at 7 ± 2 ° C, and examine how the texture and taste change over time. Then, the quality as food and the holding time of the quality were evaluated. The results are shown in Table 2.

  For comparison, instead of heat-treating for about 2 minutes in a 2% saline solution at 95 ° C., heat them for 4 minutes or 15 minutes, and treat them in the same manner as above. Shrimp B3 was produced. Further, in addition to preparing the freshly prepared shrimp A0 scooped up from the above-mentioned aquarium, the frozen shrimp A1 which was quickly frozen at −20 ° C. or less without washing and then heat-treating the shrimp A0 was also used. Manufactured.

Then, a muscle sample prepared by shelling the active shrimp A0 to which neither the heat treatment nor the freezing treatment is applied, and a muscle sample obtained by unpacking and shelling the frozen heat-treated shrimp B2 and B3 in the same manner as described above are prepared. The directional crushing strength was determined, and the chronological changes in the texture and taste of the shrimp stored in a refrigerator at 7 ± 2 ° C. were examined, and the food was evaluated. The results of these tests are also shown in Tables 1 and 2.
(Second embodiment)
Next, the frozen sweet shrimp A1 prepared in the first example was thawed, put in a 2% saline solution at 97 ° C. in a shelled state, and heat-treated for 1 minute, 3 minutes, and 15 minutes, respectively. Other than that, it processed similarly to the 1st Example, cooled, and further frozen, and manufactured frozen shrimp sweet shrimp C1, C2, and C3, respectively.

  Also, the frozen sweet shrimp A1 was half-thawed, then shelled, put into a 2% saline solution at 90 ° C., and heat-treated for 2 minutes, 5 minutes, and 15 minutes, respectively. , Cooled and further frozen to produce frozen and heat-treated sweet shrimp D1, D2 and D3, respectively.

  These frozen sweet shrimp A1, frozen heat-treated sweet shrimp C1, C2, and C3, and frozen heat-treated sweet shrimp D1, D2, and D3 were thawed in the same manner as in the first embodiment, and muscle samples were prepared. In addition to determining the crush strength in the longitudinal direction, the frozen shrimp are also thawed and stored in a refrigerator at 7 ± 2 ° C in the same manner as the thawed shrimp described above, and the texture and taste of the shrimp are determined. Changes over time were examined and evaluated as food. The test results are shown in Tables 1 and 2, respectively.

According to the above results, since the heat-treated shrimp of the present invention has been subjected to an appropriate heat treatment so that the crushing strength (N / cm ² ) is 15 to 30, the active shrimp is not heat-treated. It can be seen that the flavor is further improved as compared with the raw sashimi of A0, that it has a mellow taste and a prettier texture, and that the change in taste is moderate. In addition, since the muscle tissue is also modified, the elasticity is maintained, it is hard to cause deterioration such as softening and dehydration, and not only the taste and texture are excellent, but also the preservability is clearly improved. I understand that.

When the crushing strength (N / cm ² ) of the heat-treated shrimp exceeds 30 which is the upper limit of the range of the present invention, there is no problem in terms of the difficulty of deterioration, but the muscular tissue of the shrimp becomes hard. It will be understood that the taste and texture deteriorate, so that it is preferable to suppress the heat treatment so as not to be excessive within a range in which the storage stability can be improved.

  As described above, the heat-treated shrimp of the present invention, which has a taste and texture that is close to or rather exceeds the taste and texture of fresh shrimp, can be directly used as a raw material as well as raw material. Even if it is dried, it retains abundant taste components as it is, so it is not only useful as a frozen preserved food, but also can be used as a dry preserved food. Therefore, in the form of a fresh or dried product, it can be used as a compounding material for various processed foods, or as a material for various seasonings, or as a raw material for producing various proteins or amino acids. Depending on the application, secondary processing such as crushing, shredding, and pulverization may be added to obtain a product.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the apparatus which implements the manufacturing method of the shrimp which concerns on this invention.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Measuring part 2 Heating part 3 Primary cooling part 4 Secondary cooling part C1 Loading conveyor C2 Unloading conveyor H1 basket H2 basket H3 basket

Claims (5)

A fresh shrimp, which is in a state where there is a life reaction, is brought into contact with hot water of 85 to 98 ° C., and a sample having a thickness of 5 ± 0.2 mm obtained by cutting the shrimp tail muscle in parallel in a horizontal direction, A heat treatment characterized in that the sample is cooled immediately after a time necessary for the longitudinal crush strength at room temperature by a parallel plate type pressure tester to be in the range of 15 to 30 N per 1 cm ² of cross-sectional area of the sample. shrimp.   The heat-treated shrimp according to claim 1, wherein the shrimp is a sweet shrimp.   3. The heat-treated shrimp according to claim 1, wherein the fresh shrimp has been rapidly frozen so that the life response of the tail muscle can be restored, or has been thawed to restore the life response. 4.   The heat-treated shrimp according to any one of claims 1 to 3, wherein the fresh shrimp has not lost its life response even after its head or shell has been removed.   The heat-treated shrimp according to any one of claims 1 to 3, wherein the cooling includes freezing.

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