JP6273511B2 - Coloring method in the raw state of crustaceans and method for producing colored crustaceans - Google Patents

Description

Detailed Description of the Invention

  The present invention relates to a method for producing red color in a fresh state without heating crustaceans such as shrimp and salmon having a carotenoid pigment, and a method for producing colored crustaceans.

  Crustaceans such as shrimp and salmon are widely preferred as foods due to their beautiful red appearance and their deliciousness. Many crustaceans are dark red, blue, purple and green in the fresh state, and when heated, they develop a vivid red color for the first time. Dark shrimp, salmon, etc. are colored only by heating, because they are not tasting until they are colored bright red. Coloring of shrimp, salmon, etc. by heating is thought to cause the coloring of the carotenoid pigment, astaxanthin, etc., to combine with the protein to give various colors, but the color is released by heating and the color is bright red. .

  However, if the shellfish such as shrimp and salmon are colored by heating with water, steaming, etc., the protein in the meat is denatured, and the meat quality having the unique sweetness and umami taste is completely altered. Therefore, a so-called blanching coloring method has been proposed in which only shrimp shells are colored by boiling for a short time, and the internal meat quality is kept as fresh as possible (Patent Document 1). In addition, a method of heating crustaceans such as shrimp and salmon with far infrared rays in the presence of water vapor is disclosed (Patent Document 2).

  In the above conventional method, the crustacean coloration method by boiling for a short time is the freshness of the internal flesh in shrimp with a freshly stripped flesh, such as the so-called black tiger, which is commonly referred to as the black tiger for coloring only the shell. While maintaining the state, it is impossible to boil the surface of the stripped body so as to develop a red color. If you try to develop the color on the inside surface of the flesh, the protein in the meat part cannot be kept in a fresh state by heat denaturation. In addition, in the infrared heating method, it is impossible to heat and denature the internal flesh and keep it fresh.

  Therefore, in order to color the surface of the body vividly red while keeping the crustaceans that are dark on the surface of the fresh state in a fresh state, shellfish such as shrimp and shellfish with or without the shell are used. In addition, a crustacean coloring method in a raw state in which a carotenoid pigment is colored red by treatment with an alkaline aqueous solution has been proposed (Patent Document 3).

  However, when the above-mentioned crustacean coloring method is used, dark spots appear on the red colored surface of the shrimp after a while after coloring fresh stripped shrimp. In particular, when the colored product is frozen and shipped, and the user defrosts and waits for a while, dark spots appear to be a big problem. In addition, when a taste test is performed on the peeled shrimp or the like that has developed color by the above method, a slight bitterness may remain and there are some problems in taste.

  As a method for preventing the occurrence of dark spots and bitterness, shellfish such as shrimp and shark are treated with an alkaline aqueous solution, then treated with an acidic solution such as an acetic acid aqueous solution, and neutralized. Neutralize until the surface of the crustacean exfoliate is weakly alkaline and stop neutralization. The red color of the product can be kept clear, dark spots do not occur, and the peeled shrimp and the like that have been color-treated are immersed in a thin seasoning solution made of sugar and salt with sweetness such as sucrose. Therefore, it has been proposed that the slightly bitter taste is eliminated and an excellent taste is exhibited (Patent Literature 4).

  Furthermore, when the crustacean is colored red in the raw state with the above alkaline aqueous solution, it is possible to use a treatment solution having a pH value as low as possible by sequentially immersing the shellfish in a plurality of alkaline aqueous solutions. It has been disclosed that color development can be performed without losing as much as possible the umami component of the crustacean (Patent Document 5).

  In order to prevent blackening on the surface of the shell, especially the surface of the shells of shrimp heads, mustaches, legs, etc. The crustacean shells are blackened by treating the crustaceans in the living state with a crustacean preservation solution containing an ascorbic acid compound and an organic polybasic acid compound and / or amino acid compound, and then refrigerated or frozen. It is disclosed that the occurrence of the above can be prevented. As a comparative example with respect to the examples of the present invention, the crustacean shell to some extent is not sufficient by treating living crustaceans with a treatment liquid containing only a high concentration ascorbic acid compound of 1 g / dL or more. It is disclosed that the blackening of the film can be prevented (Patent Document 6).

JP 61-242565 A JP-A 63-129773 JP-A-6-7075 JP-A-11-89543 JP 2010-22355 A JP 2007-20566 A

  As used herein, the term “shrimp” is expressed as shrim (shrimp), prawn (freshwater shrimp), lobster (lobsters, lobsters, lobsters) when expressed in English. All things are included.

  However, in the coloring method according to the method of Patent Document 4, the crustaceans are treated with an alkaline aqueous solution in a raw state to develop a red color, and then completely neutralized by immersing in an aqueous acid solution to neutralize. Without neutralization, it is necessary to neutralize the shellfish surface until the surface of the shellfish is extremely weakly alkaline, and the treatment requires skill. It is necessary to adjust the soaking time according to the acid concentration and temperature of the acidic solution while estimating the amount of acid required to neutralize the alkali components penetrating into the shellfish body. is there. If the neutralization is too much, dark spots may appear on the surface of the peeled shrimp that develops red color after a while, which impairs the commercial value. In addition, even when neutralization is performed so that the surface of the shellfish strips is weakly alkaline, dark spots may appear on the surface of the shrimp colored in red over time. .

  Therefore, the present invention can easily carry out the step of neutralizing with crustacean stripped shellfish after being processed with an alkaline aqueous solution and then neutralizing with acidic aqueous solution. It is an object of the present invention to provide a method for coloring a crustacean in its raw state and a method for producing a colored crustacean without causing dark spots.

  In order to achieve the above-mentioned object, the present inventor has conducted extensive research, and as a result of treating the peeled shellfish such as shrimp and salmon with an alkaline aqueous solution after removing the shell, an acidic solution such as an acetic acid aqueous solution is used. Later, the crustaceans after neutralization are treated with an aqueous solution containing a reducing compound that is a water-soluble antioxidant that can be used as a food additive. Even after neutralization until it has become neutral, it is possible to keep the red color development on the surface of the flesh after the time has elapsed after freezing or once frozen and thawed, so that dark spots do not occur. As a result, the present invention has been completed.

  That is, the present invention treats crustaceans such as shrimp, shark, etc., excluding shells with an alkaline aqueous solution having a pH of 10 to 14, thereby causing the carotenoid pigment to develop a red color, and then using an aqueous solution of acetic acid or other edible acids. The crustaceans can be used as a food additive in the raw crustacean coloring method in which the surface of the crustaceans is neutralized until it becomes weakly alkaline or neutral. The gist of the method for coloring crustaceans in the raw state is characterized by treating with a blackening-preventing aqueous solution containing a reducing compound, which is a water-soluble antioxidant, at a concentration of 1000 ppm to 0.1 ppm.

  In another embodiment of the present invention, a carotenoid pigment is colored red by treating crustaceans such as shrimp, shark, etc., excluding the shell, with an alkaline aqueous solution having a pH of 10 to 14, followed by an aqueous solution of acetic acid or other edible acids. In the method for producing colored crustaceans, which is neutralized until the peeled surface of the crustaceans is weakly alkaline or neutral, the crustaceans after the neutralization can be used as a food additive. The gist of the present invention is a method for producing a colored shellfish in a raw state, which is characterized by treating with a blackening-preventing aqueous solution containing a reducing compound as an inhibitor at a concentration of 1000 ppm to 0.1 ppm.

  According to the crustacean coloring method of the present invention, the surface of the flesh can be colored red while the meat part of the crustacean is kept in a fresh state, and the appetizing raw food is vividly colored and has no blackening. You can get shrimp and salmon. Shrimp that are not appetizing because the surface of fresh stripped flesh such as shrimp is dark, can be colored with red color while keeping the fresh state by the coloring method of the present invention. It will be suitable.

  Furthermore, according to the crustacean coloring method of the present invention, there is no risk of dark spots appearing on the peeled surface of the crustacean that develops red color after a time after the crustacean coloring process, and its commercial value is increased. There is no loss. Moreover, even after neutralizing the crustaceans to red with an alkaline aqueous solution and then neutralizing to neutrality with an acidic aqueous solution, the crustaceans developed a red color after the time after the crustacean coloring process had elapsed. Since there is no risk of dark black spots appearing on the surface, neutralization can be achieved to neutrality, and since the neutralization is insufficient, there is no risk of bitterness due to the remaining alkali component.

  Further, according to the crustacean coloring method of the present invention, the process control when the crustacean is colored with an alkaline aqueous solution and then neutralized with an acidic aqueous solution becomes easy.

  As the crustaceans to be treated by the color development method of the present invention, all edible crustaceans such as shrimp and salmon can be treated, but in particular, fresh and dark brown shrimp, such as bovine shrimp, vaname shrimp, bear shrimp, shinchu web, Suitable for processing shrimp, etc.

  The alkaline aqueous solution used in the color development method of the present invention is a compound that exhibits alkalinity by dissolving in water with metal hydroxides, alkali metal salts, alkaline earth metal salts, and other salts. Even if it remains, the food must be completely safe.

  Examples of the components of the alkaline aqueous solution that can be used in the coloring method of the present invention include potassium carbonate, potassium bicarbonate, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, sodium hydroxide, magnesium carbonate, Ammonium carbonate, sodium phosphate, potassium phosphate, ammonium phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, sodium polyphosphate, potassium polyphosphate, sodium metaphosphate, potassium metaphosphate, tetrasodium pyrophosphate, tetrapotassium pyrophosphate, etc. be able to. These hydroxides or salts can be used alone or in admixture of two or more.

  The concentration of these hydroxide or salt aqueous solution varies depending on the type, but is 0.001% by weight or more. 10-14 are preferable and, as for pH of alkaline aqueous solution, 11-12 are still more preferable. Color development does not occur below pH 10. Moreover, when pH exceeds 14, there exists a possibility that the protein of the crustacean meat part may denature.

  In order to color the surface of the stripped surface with an alkaline aqueous solution of crustaceans, it is preferable to treat the stripped state with the shell removed. Spray the shellfish with an alkaline aqueous solution or immerse the shellfish in an alkaline aqueous solution. The treatment time varies depending on the type, concentration and temperature of the alkaline aqueous solution, but is usually between 1 second and 60 minutes. It is preferable to process in as short a time as possible in order to prevent outflow of meaty umami components.

  The color treatment temperature with an alkaline aqueous solution is preferably in the range of 0 ° C to 70 ° C. If the treatment is carried out at a temperature exceeding 70 ° C. for a long time, the protein is denatured by heat, and the object of the present invention to develop color in a fresh state cannot be achieved.

  When crustacean flakes are treated with an alkaline aqueous solution to invent a red color, it is desirable to provide a plurality of alkaline aqueous solution treatment tanks and sequentially immerse them in the alkaline aqueous solution treatment tanks. Coloring treatment using only one alkaline aqueous solution treatment tank does not produce sufficient red color, or even if it takes a long time to develop color, it can be reddish in a short time by immersing it again in a treatment solution made of fresh alkaline aqueous solution. The processing time can be shortened, the product quality can be prevented from being deteriorated by being immersed in the processing solution for a long time, and a high-quality product can be obtained.

  When performing the alkaline aqueous solution treatment by a plurality of alkaline aqueous solution treatment steps that are sequentially immersed in a plurality of alkaline aqueous solution treatment tanks, it is more preferable to provide a water washing step of washing with cold water between each alkaline aqueous solution treatment step. . When the crustacean exfoliation is processed with an alkaline aqueous solution to develop a red color, if the same processing solution is used many times, the color development rate decreases even if the pHH value of the processing solution hardly changes. It is recognized that The reason for this has not been elucidated, but when the crustacean flesh is immersed in an alkaline aqueous solution, some components are eluted from the crustacean flesh and the components release carotenoid pigments such as astaxanthin bound to the protein. It may be a hindrance to the reaction.

  Therefore, it is possible to immerse in a fresher next-stage treatment liquid by sequentially immersing in a plurality of alkaline aqueous solutions. In addition, by providing a water washing step between each of the plurality of alkaline aqueous solution treatment steps, the treatment solution of the previous alkaline aqueous solution treatment step is brought into the treatment solution of the subsequent treatment step with the shellfish peeled off. And the processing liquid in the next stage can be kept as fresh as possible. This rinsing step is preferably provided at least between the first-stage alkaline aqueous solution treatment step and the second-stage alkaline aqueous solution treatment step. By such an operation, the alkaline aqueous solution at each stage can be repeatedly used a plurality of times without being discarded for each treatment.

  Even when shrimp having a dark shell such as bull shrimp and vanamae shrimp are treated with an alkaline aqueous solution with a shell, it is difficult to cause the shell to develop a bright red color. Except for these shrimp shells, the strips are colored red, and when selling the shrimp strips that are colored red, depending on the use as a shrimp food, the state of the strips leaving the tail of the shrimp You may need to sell at. At that time, the shrimp tail with a bright red color rather than the dark shrimp tail is more appetizing and the value of the product increases. The shrimp tail shell is made bright red by the blanching method that heats only the tail of the shrimp, and then the shell other than the tail is peeled off to form a stripped state, followed by a color treatment with an alkaline aqueous solution. . Accordingly, the terms “shrimp excluding shells” and “peeled” in the present invention include those that leave only the shrimp tail shell and other portions of the shell.

  As a reducing compound which is a sex antioxidant that can be used as a food additive to be contained in a blackening prevention aqueous solution that is processed after neutralizing colored crustaceans, L-ascorbic acid (vitamin C) or a salt thereof, erythorbic acid or The salt, catechin, tocopherol (vitamin E) or a derivative thereof, sulfite or hyposulfite is used. There are various types of catechins, but any catechin can be used. Tocopherol has 8 types of optical isomers, any of which can be used, and may or may not have optical activity. As sulfites and hyposulfites, sodium salts and potassium salts are preferably used. A mixture of a plurality of these reducing compounds can also be used.

  The concentration of the reducing compound in the blackening prevention aqueous solution is 1000 ppm to 0.1 ppm, preferably 100 ppm to 0.2 ppm, more preferably 10 to 0.3 ppm. Reducing compounds in the blackening-preventing aqueous solution are the treatment of the shellfish stripping with the blackening-preventing aqueous solution at the final stage of the stripping process. If it remains in the product, it will affect the taste of the product. For this reason, it is desirable to use the reducing compound at the lowest possible concentration.

  Crustaceans and the like that have been color-treated with an alkaline aqueous solution are neutralized by washing with a neutralization treatment solution consisting of an acetic acid aqueous solution until pH 7.0 to 10 after washing with water for a short time. A preferred concentration of the acetic acid aqueous solution is 0.1 to 2.0% by weight. The neutralization treatment may not be carried out until the peeled shellfish is completely neutral, but may be neutralized to such an extent that slightly weak alkalinity remains or may be completely neutralized. By completely neutralizing, there is no risk of bitterness due to the remaining alkali component.

  The degree of neutralization is preferably neutralized so that the pH of the surface measured after wiping off the treatment liquid from the surface of the shellfish shells is 7.0-10. More preferably, the neutralized surface is neutralized so that the pH of the surface is 7.0 to 9.0. When the pH of the surface after neutralization exceeds 10, a large amount of alkali components remain in the peeled meat and the like, and the bitterness remains and affects the taste.

  The acidic component of the neutralization treatment liquid is not limited to acetic acid, and may be other edible organic acids or inorganic acids. For example, organic acids such as malic acid, succinic acid, citric acid, hydrochloric acid, and the like can be used, but acetic acid is preferably used from the viewpoint of taste when a trace amount remains after the treatment. Regardless of which acid is used, it is necessary to adjust the final pH of the stripped surface after the neutralization treatment to be in the range of 7.0 to 10. The temperature of the neutralization treatment is 0 to 40 ° C, preferably 10 to 25 ° C, and more preferably 15 to 20 ° C. The time required for the neutralization treatment varies depending on the type and temperature of the neutralization treatment liquid, but usually 1 to 30 minutes are necessary, and 5 to 15 minutes are preferable. This neutralization treatment may be performed by sequentially immersing in two neutralization tanks, but the total immersion time is the above time. If this time is short, the inside of the strip cannot be neutralized, and if it is too long, the crustacean flavor component may flow out and be lost.

  The neutralized crustaceans and the like are washed with water for a short time and then immersed in an aqueous solution for preventing blackening. It is preferable to mix a seasoning with the blackening prevention aqueous solution so that the seasoning liquid is also used. Although the blackening prevention aqueous solution and the seasoning liquid can be prepared separately and processed separately, it is preferable to reduce the number of times of immersion in the processing liquid as much as possible, because the outflow of the umami component of the crustacean can be prevented.

  In order to make it contain in blackening prevention aqueous solution and serve as a seasoning liquid, the seasoning mixed with blackening prevention aqueous solution has preferable 2-15 weight% of sucrose and 1-6 weight% of salt, and sucrose density | concentration is 4-10 weight%. % Is more preferable, and 6 to 8% by weight is still more preferable. The salt concentration is more preferably 2 to 4% by weight. 0-40 degreeC is used for the temperature of blackening prevention aqueous solution and seasoning liquid, and 10-25 degreeC is preferable. The time required for the seasoning varies depending on the type and temperature of the seasoning liquid, but is usually preferably 10 to 30 minutes. If this time is short, the seasoning liquid does not penetrate into the inside of the strip, and if it is too long, the crustacean umami component may flow out and be lost.

  The sweetening component of the seasoning liquid is not limited to sucrose, and the same is true for a seasoning liquid in which salt is added to an aqueous solution of other saccharides having a sweetness equivalent to that of the sucrose aqueous solution at the above concentration to the above concentration. Although sucrose, especially granulated sugar, which is pure sucrose, is used, it is most preferably used because the sweetness is clean, there is no miscellaneous taste, and an unnatural taste is not added to the seasoned strip. In addition to sucrose or other sugars and salt at the above concentrations, umami seasonings and other seasonings may be appropriately added to the seasoning liquid.

  By this treatment with the seasoning liquid, the slight bitterness often observed in the taste test after the color development treatment of crustaceans such as the shrimp of the shrimp is alleviated and hardly observed in the sensory test.

Examples and Comparative Examples

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.

[Example 1]
The strip of bovine shrimp is peeled off, the stomach is opened, and the intestinal tract (back) is removed. As the sterilizing cleaning liquid for foods, a known sterilizing cleaning liquid for foods obtained by diluting an aqueous solution containing sodium hypochlorite obtained by subjecting a dilute sodium hypochlorite aqueous solution or a saline aqueous solution to electroless membrane electrolysis is used.

  The disinfected striped bovine shrimp is immersed for about 2 minutes in a color developing preliminary tank containing an aqueous potassium carbonate solution having a pH of 12.0 and a concentration of 5.0% by weight. Next, color is developed by immersing in a coloring tank containing an aqueous potassium carbonate solution of the same concentration for about 3 minutes. The strip is then washed with running water for about 1 minute to remove most of the potassium carbonate. By this color treatment, the striped shrimp developed a red striped pattern.

  Next, the peeled colored shrimp is dipped in a pre-neutralization tank containing 1.4 wt% acetic acid aqueous solution of pH 3.5 for about 1 minute, and then placed in a neutralization tank containing an acetic acid aqueous solution of the same concentration. Immerse for 10 minutes and finally neutralize until the pH of the stripped surface becomes about 7.5, and the potassium carbonate impregnated inside the stripped surface is almost neutralized. The strip is then washed with running water for about 1 minute.

  Next, the neutralized bovine shrimp was immersed in an anti-blackening aqueous solution and seasoning solution containing 0.0001% by weight of L-ascorbic acid, 7% by weight of granulated sugar and 3% by weight of sodium chloride for about 10 minutes. The resulting colored shrimp strips were drained and shaped, vacuum packaged and frozen to obtain a product. It is preferable to keep the temperature during each treatment step of the above-mentioned stage bacteria, color development, neutralization and seasoning at 20 ° C. or less.

  When the frozen shrimp of the boiled shrimp obtained in the color development step was thawed and allowed to stand at 10 ° C. for 12 hours, dark black spots did not appear on the colored surface of the striped bull shrimp. As a result of a taste test of the dehydrated bovine shrimp, the taste was almost the same as that of the raw striped shrimp, and no bitterness was felt.

[Example 2]
In exactly the same manner as in Example 1, after the boiled shrimp strips were sterilized, the same color development treatment was performed, then immersed in water for 1 minute, and then immersed in a neutralization tank containing a 2.0 wt% acetic acid aqueous solution. Neutralize until the pH of the stripped surface reaches about 7.5, and substantially neutralize the potassium carbonate impregnated inside the stripped surface. The strip is then washed with running water for about 1 minute. Using the resulting colored bovine shrimp peeled off, a blackening-preventing aqueous solution and seasoning solution containing 0.001% by weight of erythorbic acid, 7% by weight of granulated sugar and 3% by weight of salt, and other processing conditions were the same. By processing, drained and shaped, vacuum packaged and frozen. When this was thawed and allowed to stand at 10 ° C. for 5 hours, no blackening occurred on the surface of the stripped colored shrimp. In addition, a taste test was performed on the stripped bovine shrimp, and there was almost no difference in taste between the raw striped shrimp and no bitterness.

[Comparative Example 1]
In exactly the same manner as in Example 1, after the boiled shrimp strips were sterilized, the same color development treatment was performed, then immersed in water for 1 minute, and then immersed in a neutralization tank containing a 2.0 wt% acetic acid aqueous solution. Neutralize until the pH of the stripped surface reaches about 7.5, and substantially neutralize the potassium carbonate impregnated inside the stripped surface. The strip is then washed with running water for about 1 minute. The resulting colored shrimp strips were shaped by draining them as they were without being treated with an anti-blackening aqueous solution and a seasoning solution, vacuum-packed and frozen. When this was thawed and allowed to stand at 10 ° C. for 5 hours, some dark black spots were generated on the surface of the colored shrimp strips. A taste test was conducted on the thawed strip of bovine shrimp and a slight bitter taste was felt.

Example 3
In Example 1, vanamae shrimp was used as a crustacean, and it was immersed in a pre-immersion tank containing 6.25% by weight of potassium carbonate and a color treatment solution of pH 11.45 as a color treatment solution with occasional stirring for 15 minutes. Then, it was immersed for 15 minutes in a coloring immersion tank containing the same coloring treatment solution. This was washed with water and neutralized in the same manner as in Example 1 and neutralized until the surface of the stripped meat reached pH 7.0. The neutralized vaname shrimp stripped sodium sulfite 0.00003% by weight, granulated sugar 7% by weight and salt 3 It was immersed for about 10 minutes in a blackening-preventing aqueous solution and seasoning solution containing% by weight. The resulting colored striped shrimp was drained and shaped, vacuum packaged and frozen to obtain a product. The obtained lobster shrimp colored in red.

  When the frozen product of the shrimps obtained in the color development step was thawed and allowed to stand at 10 ° C. for 12 hours, dark black spots did not appear on the colored surface of the strip of shrimps. When the striped striped shrimp was taste tested, the taste was almost the same as that of the raw striped shrimp, and no bitterness was felt.

[Comparative Example 2]
After sterilization treatment and color development treatment of the striped shrimp of the same name as in Example 3, after 30 minutes washing with water and neutralization treatment, it is immersed in a seasoning liquid containing no reducing compound and containing the same concentration of seasoning, After freezing the colored shrimp, the frozen product was thawed and allowed to stand at 10 ° C. for 5 hours. As a result, many small dark spots were formed on the surface of the striped shrimp.

Example 4
The shelled shrimp with its head removed is sterilized by washing with a sterilizing washing solution for food, and only the tail part is soaked in 90-95 ° C hot water for 2 minutes to blanch, and only the tail shell is red. The color was developed. After cooling this, peel off the shells other than the tail shell and wash with a food sterilization cleaning solution. Washed with water. This strip was put into a first color developing tank containing a color developing solution of potassium carbonate 6.25% by weight and pH 11.45 and immersed for 15 minutes with occasional stirring. The stripped material was taken out from the first color developing tank and washed with cooling water, and then placed in a second color developing tank containing a color developing solution having the same concentration as described above, and immersed for 15 minutes with occasional stirring. The peeled strip that had undergone color development was taken out of the second color treatment tank and washed with cooling running water, and then the belly was opened to remove the internal organs. This was washed with water and neutralized in the same manner as in Example 3 and neutralized until the peeled surface became pH 7.0. The neutralized striped shrimp was added to 0.001% by weight of L-ascorbic acid, 7% by weight of granulated sugar and It was immersed for about 10 minutes in a blackening-preventing aqueous solution and seasoning solution containing 3% by weight of sodium chloride. This strip was washed with cooling water, drained, placed in a tray, vacuum-packed and rapidly frozen to obtain a product. The obtained lobster shrimp colored in red.

  When the frozen vaname shrimp obtained in the above step was thawed and allowed to stand at 10 ° C. for 12 hours, no dark black spots appeared on the colored surface of the striped shrimp. When the striped striped shrimp was taste tested, there was almost no difference in taste between the raw striped shrimp and no bitterness.

  The color developing solution in the second color developing tank of Example 4 above can be used repeatedly, even if it is used in at least two treatments, the color developing ability does not decrease, and the use amount of the color developing solution is reduced. The burden of waste liquid treatment accompanying disposal of the treatment liquid can be reduced.

  Shrimp such as bull shrimp and vanamae shrimp that are colored in red with an alkaline aqueous solution are widely used as sushi, etc., and the crustacean coloring method of the present invention prevents the shrimp from blackening. Can be widely used in industry.

Claims (7)

By treating shellfish such as shrimp and cocoon without shells with an alkaline aqueous solution of pH 10 to 14, the carotenoid pigment is colored red, and then treated with an aqueous solution of acetic acid or other edible acid, In the method for coloring crustaceans in a raw state, where the surface of the shellfish skin is neutralized until it becomes weakly alkaline to neutral, the crustaceans after neutralization are treated with L-ascorbic acid or a salt thereof, erythorbic acid Or a crustacean coloring method in a raw state, characterized by treating with a blackening-preventing aqueous solution containing a salt thereof at a concentration of 10 ppm to 0.3 ppm. By treating shellfish such as shrimp and cocoon without shells with an alkaline aqueous solution of pH 10 to 14, the carotenoid pigment is colored red, and then treated with an aqueous solution of acetic acid or other edible acid, In a method for coloring crustaceans in a raw state in which the surface of the crustacean flesh is neutralized until it becomes weakly alkaline to neutral, the crustaceans after neutralization are treated with catechin, tocopherol or a derivative thereof at 100 ppm to 0. A method for coloring crustaceans in a raw state, characterized by treatment with a blackening-preventing aqueous solution containing a concentration of 2 ppm.   The shell in the raw state according to claim 1 or 2, wherein the blackening prevention aqueous solution is a seasoning liquid containing 2 to 15% by weight of sucrose or other sugars having a concentration exhibiting an equivalent sweetness and 1 to 6% by weight of sodium chloride. Coloring method.   In the step of treating the crustaceans with the alkaline aqueous solution, a plurality of alkaline aqueous solution treatment steps are provided in which a plurality of treatment tanks for the alkaline aqueous solution are provided, and the crustaceans are sequentially immersed in the plurality of alkaline aqueous solution vessels. The method for coloring crustaceans in the raw state according to 2 or 3. In the step of treating the crustacean with the alkaline aqueous solution, a plurality of treatment tanks for the alkaline aqueous solution are provided, and in the plurality of alkaline aqueous solution treatment steps for sequentially immersing the crustaceans in the plurality of alkaline aqueous solution vessels, The raw shellfish coloring method according to claim 4, wherein a water washing step of washing with cold water is provided during the aqueous solution treatment step or at least between the first alkaline aqueous solution treatment step and the second alkaline aqueous solution treatment step. In the neutralization step of neutralizing an aqueous solution of the acid, a plurality of processing tanks of an aqueous solution of acid, according to claim 1, 2, 3, 4 immersed in an aqueous solution bath of sequential plurality of acid該甲shells such, or 5. A method for coloring a crustacean in a raw state according to 5 . By treating shellfish such as shrimp and cocoon without shells with an alkaline aqueous solution of pH 10 to 14, the carotenoid pigment is colored red, and then treated with an aqueous solution of acetic acid or other edible acid, In the method for producing a colored crustacean that is neutralized until the surface of the peeled shellfish is weakly alkaline to neutral, the shellfish after neutralization is treated with L-ascorbic acid or a salt thereof, erythorbic acid or a salt thereof 10- 0.3 ppm or catechin, tocopherol or a derivative thereof from 100 ppm to 0. A method for producing a colored shellfish in a raw state, characterized by treatment with a blackening-preventing aqueous solution containing a concentration of 2 ppm.