Water for treating seafood, method for treating seafood, and method for producing fresh seafood

Abstract

Provided are water for treating seafood, a method for producing the same, and a method for producing seafood whose freshness is maintained. [Solution] Seafood processing water contains electrolyzed water and an alkalizing agent, and has a pH greater than 7.0 and not greater than 10.5. The alkalizing agent is added to acidic electrolyzed water to produce seafood processing water with a pH greater than 7.0 and not greater than 10.5. By applying this seafood processing water to seafood, seafood that has been kept fresh can be produced.

Description

[Technical Field]

[0001] The present invention relates to water for treating seafood, a method for treating seafood, and a method for producing seafood whose freshness is maintained. [Background technology]

[0002] Demand for seafood has been increasing in recent years not only in Japan but also overseas, and technology for processing landed seafood has been attracting attention.

[0003] For example, Patent Document 1 (Japanese Patent No. 7266345) discloses water for processing seafood, which contains carbon dioxide and is acidic electrolyzed water with a pH of 4 to 7, and is used to remove blood, reduce slime, prevent deterioration of flesh, or improve color and luster.

[0004] This document states that seafood generally contains a large amount of trimethylamine oxide (TMAO) in its flesh, which is converted into trimethylamine (TMA) from the time of capture, and that the generation of TMA causes a foul odor and reduces quality. It also states that some seafood products have a foul odor due to residual blood, which requires a long deodorization process such as salting, resulting in higher production costs.

[0005] In the invention of Patent Document 1, acidic electrolyzed water containing carbon dioxide and having a pH of 4 to 7 is used to inhibit the production of TMA in seafood, thereby preventing the quality of the seafood from deteriorating. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7266345 Summary of the Invention [Problem to be solved by the invention]

[0007] Patent Document 1 describes that it is possible to inhibit the reaction in which trimethylamine oxide (TMAO) in seafood is converted to trimethylamine (TMA), but this reaction is a reduction reaction in which trimethylamine oxide is reduced to produce trimethylamine and oxygen, and there is no mention of inhibiting oxidation reactions in the seafood treatment water described in Patent Document 1.

[0008] Generally, when seafood oxidizes, it becomes difficult to maintain its freshness, resulting in discoloration and deterioration of flavor.

[0009] Therefore, an object of the present invention is to provide seafood processing water capable of suppressing oxidation of seafood, a seafood processing method, and a method for producing seafood that maintains freshness. [Means for solving the problem]

[0010] As a result of extensive research to achieve the above-mentioned object, the inventors of the present invention surprisingly discovered that oxidation of seafood can be suppressed by adjusting the pH of electrolyzed water, which is inherently weakly acidic, by adding an alkalizing agent, and thus completed the present invention.

[0011] That is, the present invention can be configured in the following manner. [Aspect 1] Water for seafood processing, containing electrolyzed water and an alkalizing agent, and having a pH greater than 7.0 and not greater than 10.5. [Aspect 2] 2. The seafood treatment water according to claim 1, wherein the alkalinizing agent has a pH of 7.5 or higher. Aspect 3 The seafood processing water according to Aspect 1, wherein the alkalinizing agent is at least one selected from the group consisting of calcium carbonate, magnesium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, trisodium citrate, sodium gluconate, potassium gluconate, sodium lactate, potassium lactate, sodium acetate, disodium dihydrogen pyrophosphate, sodium DL-malate, disodium succinate, and monosodium succinate. Aspect 4 Aspect 4. The water for treating seafood according to any one of Aspects 1 to 3, having a salt concentration of 0.1% by mass to 20% by mass. Aspect 5 Aspect 4. The fish and shellfish treatment water according to any one of Aspects 1 to 3, wherein the concentration of hypochlorous acid is 5 ppm or less. Aspect 6 A method for producing water for treating seafood with a pH greater than 7.0 and less than 10.5, comprising the step of adding an alkalizing agent to acidic electrolyzed water. Aspect 7 A method for producing water for treating seafood according to Aspect 6, wherein the electrolyzed water is acidic electrolyzed water obtained by electrolyzing raw water having a chlorine concentration of 0.1 mg / L or more and 1.0 mg / L or less. Aspect 8 A method for producing seafood whose freshness is maintained, comprising the step of applying the seafood processing water according to any one of aspects 1 to 5 to seafood. Aspect 9 The method of producing seafood of embodiment 8, wherein the application is by spraying, compressing, immersion, running water, or a combination thereof. [Effects of the Invention]

[0012] According to the seafood treatment water of the present invention, by adjusting the pH by adding an alkaline agent to electrolyzed water, which is originally weakly acidic, the freshness of seafood can be maintained when the treatment water is applied to seafood. [Brief explanation of the drawings]

[0013] The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and description purposes and should not be used to define the scope of the present invention.

[0014] [Figure 1] This is a photograph showing the state of mackerel fillets five days after various types of seafood treatment water were applied to the mackerel. DETAILED DESCRIPTION OF THE INVENTION

[0015] The seafood processing water contains electrolyzed water and an alkalizing agent. From the viewpoint of maintaining freshness, the seafood processing water has a pH of more than 7.0 and not more than 10.5. The pH of the seafood processing water may be preferably not less than 7.1, preferably not less than 7.3, more preferably not less than 7.6, and even more preferably not less than 7.8, or may be preferably not more than 10.0, more preferably not more than 9.5, and even more preferably not more than 9.0.

[0016] Electrolyzed water can be produced by electrolyzing raw water such as natural water, tap water, or mineral water. The raw water may contain a small amount of chlorine. If the raw water contains chlorine, the chlorine concentration (residual chlorine concentration) may be, for example, 0.1 mg / L or more and 1.0 mg / L or less. The chlorine concentration can be measured, for example, by the DPD method using a residual chlorine meter. The raw water may be electrolyzed using a known electrolytic device such as a diaphragm electrolytic cell, a diaphragm-less electrolytic cell, etc. When a diaphragm electrolytic cell is used, acidic electrolyzed water is used.

[0017] Electrolyzed water processed by an electrolysis device is usually weakly acidic (pH 2.7 or higher but lower than 5) to slightly acidic (pH 5.0 or higher but lower than 6.9), so by adding an alkalizing agent, the pH can be adjusted to a predetermined range to produce water for processing seafood.

[0018] The alkaline agent is used to adjust the pH of electrolyzed water to a predetermined value. The alkaline agent is not particularly limited as long as it can adjust the pH. Examples include calcium carbonate, magnesium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, trisodium citrate, sodium gluconate, potassium gluconate, sodium lactate, potassium lactate, sodium acetate, disodium dihydrogen pyrophosphate, sodium DL-malate, disodium succinate, and monosodium succinate. These substances may be used alone or in combination of two or more. Of these, potassium carbonate and calcium carbonate are preferred. The pH of the alkaline agent may be the value in a 10 mM aqueous solution, for example, pH 7.5 or higher, preferably 8.5 or higher, and more preferably 9.5 or higher.

[0019] In the water for treating seafood, the chlorine concentration (residual chlorine concentration) may be 1.0 mg / L or less, preferably 0.5 mg / L or less, more preferably 0.3 mg / L or less, and even more preferably 0.1 mg / L or less.

[0020] The fish and shellfish processing water may further contain sodium chloride. The salinity can be determined by immersing an ion selective electrode in the liquid, measuring the potential of chloride ions, and converting the measured value into salinity.

[0021] The salt concentration may be, for example, 0.1% by mass to 20% by mass, preferably 0.5% to 10% by mass, and more preferably 1.0% to 3% by mass. In the case of seafood that lives in seawater, the inclusion of salt has the advantage of suppressing discoloration and improving color and luster.

[0022] The seafood processing water may contain hypochlorous acid derived from the electrolysis of raw water, and the inclusion of hypochlorous acid can enhance the sterilization effect. The concentration of hypochlorous acid may be, for example, 5 ppm or less, preferably 3 ppm or less.

[0023] The temperature of the seafood processing water can be set as appropriate, but from the viewpoint of easily maintaining the freshness of the seafood, it may be, for example, 0°C to 20°C, preferably 0°C to 10°C, and more preferably 0°C to 5°C.

[0024] The seafood treatment water can suppress oxidation of seafood and can be applied to various seafood. Examples of seafood include saltwater fish (red fish such as mackerel, sardines, herring, horse mackerel, bonito, and tuna, white fish such as sand lance, pacific saury, yellowtail, yellowtail, amberjack, red sea bream, alfonsino, tilefish, black porgy, rockfish, flounder, plaice, cod, whiting, sea bass, blackfin sea bass, Spanish mackerel, shishamo, conger eel, and Atka mackerel, and cartilaginous fish such as rays and sharks), freshwater fish (e.g., eel, salmon, trout, sweetfish, yamame trout, and char), shellfish (scallops, clams, These include bivalves such as clams, clams, oysters, mussels, cockles, giant clams, surf clams, razor clams, blood shells, sea cucumbers, mussels, and mussels, as well as gastropods such as turban shells, abalone, turban shells, whelks, and tokobushi clams, crustaceans (shrimp, mantis shrimp, crabs, etc.), cephalopods (octopus, squid, etc.), echinoderms (sea urchins, sea cucumbers, etc.), mammals (whales, dolphins, etc.), fish eggs (mullet ovaries, salmon roe, etc.), and seaweed (sea lettuce, nori, wakame, kelp, etc.).

[0025] The present invention also encompasses a method for producing seafood whose freshness is preserved, which includes a step of applying seafood processing water to the seafood. The step of applying the seafood processing water to the seafood is not particularly limited, and the seafood processing water can be applied by spraying, compressing, immersion, running water (for example, spraying or sprinkling), or a combination thereof.

[0026] When spraying seafood treatment water onto seafood, the seafood treatment water may be applied to the surface of the seafood using a spray bottle or the like.

[0027] When seafood is applied with seafood treatment water, the seafood may be wrapped and held in paper, cloth, or the like that has been previously impregnated with seafood treatment water. The holding time is not particularly limited, but may be, for example, the time when the seafood treatment water comes into contact with the surface of the seafood by wrapping, or the holding time may be extended as necessary.

[0028] When soaking seafood, the seafood may be soaked in seafood processing water for a predetermined period of time. The state of the seafood during soaking is not particularly limited, but it is preferable to soak the seafood before cutting it into fillets. The immersion time may be, for example, the time when the seafood processing water comes into contact with the surface of the seafood, and the holding time may be extended as necessary.

[0029] The seafood treatment water may be used as running water when washing the seafood, may be applied to the seafood by spraying it from a hose, or may be sprayed on the seafood like a shower.

[0030] These application methods (e.g., spraying, compressing, immersion, and running water) may be used in combination of two or more, and when combined, the order is not particularly limited. For example, the seafood may be immersed after running water, or the seafood may be immersed, removed, and further run water over it.

[0031] The timing of application may be immediately after catching the fish, or may be a predetermined time after catching the fish, or may be any time until the fish is served as a meal. Preferably, it is as close to immediately after catching the fish as possible in order to maintain the freshness of the fish. [Example]

[0032] The present invention will be described in more detail below by showing examples and comparative examples, but the present invention is not limited to these examples and comparative examples. In the following examples and comparative examples, various physical properties were measured by the following methods.

[0033] [Application test for mackerel] The mackerel obtained was immersed in the processing water (15-20°C) obtained in the test example for approximately 1-5 seconds, and then cut into fillets 5 days after immersion. The condition of the fish was observed for the condition of the internal organs immediately after cut into fillets, the firmness of the flesh when cut into fillets, and the condition of the blood vessels and color of the flesh 2 hours after cut into fillets, and evaluated using the following criteria.

[0034] (Built-in state) A: It does not turn reddish-black and is elastic. B: It has not turned reddish-black, but it has lost its elasticity. C: Not only has it turned reddish-black, but it has also lost its elasticity.

[0035] (Blood vessel condition) A: The blood vessels are a vivid red color, and the boundary between the blood vessels and the flesh is clearly defined. B: The blood vessels have turned a dull red, making it difficult to distinguish the boundary between the blood vessels and the flesh. C: The blood vessels have turned a dark red, making it difficult to distinguish the boundary between the blood vessels and the flesh.

[0036] (Flesh color) A: The flesh has a transparent color, similar to the state immediately after the treatment water was applied. B: The treated water has turned white compared to the state immediately after application, and is inferior in terms of transparency. C: The treated water has turned red compared to the state immediately after application.

[0037] (Firmness of the flesh when filleted) A: The body feels firm. B: The flesh is soft and not firm. C: The body is limp and falling apart.

[0038] [Test Example 1] (pH 2.0) Using tap water as the raw water, acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation), and citric acid was added to obtain water for seafood processing with a pH of 2.0.

[0039] [Test Example 2] (pH 5.0) Using tap water as the raw water, acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation), and citric acid was added to obtain water for seafood processing with a pH of 5.0.

[0040] [Test Example 3] (pH 7.1) Using tap water as the raw water, acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation), and potassium carbonate was added to obtain water for seafood processing with a pH of 7.1.

[0041] [Test Example 4] (pH 7.2) Using tap water as the raw water, acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation), and potassium carbonate was added to obtain water for seafood processing with a pH of 7.2.

[0042] [Test Example 5] (pH 8.0) Using tap water as the raw water, acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation), and potassium carbonate was added to obtain water for seafood processing with a pH of 8.0.

[0043] [Test Example 6] (pH 10.0) Using tap water as the raw water, acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation), and potassium carbonate was added to obtain water for seafood processing with a pH of 10.0.

[0044] [Test Example 7] (pH 12.0) Using tap water as the raw water, acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation), and potassium carbonate was added to obtain water for seafood processing with a pH of 12.0.

[0045] [Test Example 8] (pH 7.1 + salt concentration 3.0%) Salt was added to the fish and shellfish treatment water obtained in Test Example 3 to obtain fish and shellfish treatment water with a salt concentration of 3.0% and a pH of 7.1.

[0046] [Test Example 9] (pH 7.2 + salt concentration 3.0%) Salt was added to the water for treating seafood obtained in Test Example 4 to obtain water for treating seafood with a salt concentration of 3.0% and a pH of 7.2.

[0047] [Test Example 10] (pH 8.0 + salt concentration 3.0%) Salt was added to the water for treating seafood obtained in Test Example 5 to obtain water for treating seafood with a salt concentration of 3.0% and a pH of 8.0.

[0048] [Test Example 11] (Non-electrolyzed water of pH 8.0) Potassium carbonate was added to tap water to obtain water for processing seafood with a pH of 8.0.

[0049] The chlorine concentration and electrical conductivity of tap water and the water obtained in Test Example 5 are shown in Table 1. Although chlorine was detected in tap water by the DPD method, it was not detected as a chlorine concentration in the treated water because it existed as chloride ions.

[0050] [Table 1]

[0051] [Table 2]

[0052] As shown in Table 2, in Test Example 1 (pH 2.0), Test Example 2 (pH 5.0), and Test Example 7 (pH 12.0), the condition of the blood line was poor despite the use of electrolyzed water, and the blood line was a dark red in all test plots. On the other hand, in Test Examples 3 to 5 and 8 to 10 (pH 7.1, pH 7.2, pH 8.0), the condition of the blood line was very good in all test plots by adjusting the pH of the electrolyzed water with an alkaline agent. In Test Example 6 (pH 10.0), the condition of the blood line was slightly worse, but it was still good compared to the poor condition of the blood line in Test Example 1 and other samples.

[0053] Regarding the flesh color, the flesh was able to maintain a transparent color in Test Examples 3 to 6 and 8 to 10 (pH 7.1, pH 7.2, pH 8.0, pH 10.0). On the other hand, the transparency of the flesh color was slightly poor in Test Example 2 (pH 5.0), and the flesh color turned red in Test Example 1 (pH 2.0) and Test Example 7 (pH 12.0).

[0054] Furthermore, regarding the firmness of the flesh when filleted, Test Example 1 (pH 2.0), Test Example 2 (pH 5.0), and Test Example 7 (pH 12.0) all lost their firmness and began to crumble. On the other hand, Test Example 3 (pH 7.1) and Test Example 8 (pH 8.0) were able to maintain their firmness. Furthermore, although the flesh became slightly softer in Test Example 4 (pH 7.2), in Test Example 9 (pH 7.2 + salt), which had salt added, the flesh became firm like Test Example 8. Therefore, considering that Test Example 6 (pH 10.0) was in a state similar to that of Test Example 4, it appears that adding salt can improve the flesh quality.

[0055] Regarding the condition of the internal organs, in Test Example 1 (pH 2.0), Test Example 6 (pH 10.0), and Test Example 7 (pH 12.0), the internal organs turned dark red and lost their elasticity. On the other hand, in Test Examples 8 and 10 (pH 8.0), the internal organs did not discolor and were able to maintain their elasticity. Furthermore, in Test Example 3 (pH 7.1), the internal organs lost their elasticity, but in Test Example 8 (pH 7.1 + salt), which had salt added, the internal organs were able to maintain the elasticity of Test Example 8.

[0056] Furthermore, among test examples 1 to 10, very good results were obtained by using test examples 5 and 10, which are electrolyzed water with a pH of 8.0, whereas when test example 11 (non-electrolyzed water with a pH of 8.0) was used, the fish could not be maintained in good condition.

[0057] In the experiments, the temperature of the treatment water when applied was 15 to 20°C, but for seafood, it is preferable to apply treatment water at a lower temperature. For example, better results can be expected if the treatment water is at 0 to 10°C, more preferably 0 to 5°C.

[0058] [Bacterial testing for mackerel] Mackerel was immersed in the treatment water obtained in Test Example 5 and stored in a refrigerator at 2°C. After that, the mackerel was stored for 5 days after immersion and the occurrence of general viable bacteria, coliform bacteria, and Staphylococcus aureus was investigated by requesting Bureau Peritas FEAC Co., Ltd. In addition, sterilized seawater was immersed in the mackerel instead of the treatment water, and the occurrence of bacteria was similarly investigated. The results of the survey are shown in Table 3.

[0059] [Table 3]

[0060] As shown in Table 3, when the treatment water of Test Example 5 (pH 8.0) was used, the proliferation of general viable bacteria was significantly suppressed compared to when sterilized seawater was used.

[0061] As described above, the preferred embodiment of the present invention has been described. However, those skilled in the art will easily imagine various changes and modifications within the obvious scope after reading the specification and drawings. Therefore, such changes and modifications are to be construed as falling within the scope of the invention as defined by the claims.

Claims

1. A method for producing water for treating seafood having a pH greater than 7.0 and not greater than 10.5, comprising the step of adding an alkalizing agent to acidic electrolyzed water.

2. 2. The method for producing water for treating seafood according to claim 1, wherein the electrolyzed water is acidic electrolyzed water obtained by electrolyzing raw water having a chlorine concentration of 0.1 mg / L or more and 1.0 mg / L or less.

3. 2. The method for producing water for treating seafood according to claim 1, wherein the alkalizing agent has a pH of 7.5 or higher.

4. 2. The method for producing seafood treatment water according to claim 1, wherein the alkalizing agent is at least one selected from the group consisting of calcium carbonate, magnesium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, trisodium citrate, sodium gluconate, potassium gluconate, sodium lactate, potassium lactate, sodium acetate, disodium dihydrogen pyrophosphate, sodium DL-malate, disodium succinate, and monosodium succinate.

5. A method for producing seafood processing water described in any one of claims 1 to 4, wherein the salt concentration of the seafood processing water is 0.1 mass% to 20 mass%.

6. A method for producing seafood treatment water described in any one of claims 1 to 4, wherein the concentration of hypochlorous acid in the seafood treatment water is 5 ppm or less.

7. A method for producing seafood treatment water described in any one of claims 1 to 4, wherein the residual chlorine concentration of the seafood treatment water is 1.0 mg / L or less.

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