JP4066240B2 - Shellfish freshness maintenance method and transportation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for maintaining the freshness of shellfish and a transport method , and more particularly to a method for maintaining the freshness of shellfish by increasing the concentration of nutrients in shellfish.
The present invention particularly relates to transportation of shellfish (fresh shellfish) as a food from the production area to the consumption area, transportation of shellfish used for the creation and regeneration of natural environments such as tidal flats, and a temporary protection place for inhabiting shellfish on the development site. It can be used effectively for transportation to a relocation site.
[0002]
[Prior art]
Shellfish such as oysters, scallops, swordfish, and clams are cultivated using, for example, natural phytoplankton and suspensions as nutrient sources in inner bays, lakes, and rivers where the effects of waves are relatively small. After being landed, the cultured shellfish purify the filth and fungi accumulated in the body and are usually transported to the consumption area in an anhydrous state. Nutrients stored in the shellfish shellfish during landing are gradually metabolized and reduced during purification and transportation, so that the freshness of the shellfish has been prevented from decreasing so that the freshness of the shellfish is not lost in the consumption area. Various measures are taken.
[0003]
An example of a measure for preventing a decrease in freshness of shellfish is a low-temperature transport method in which shellfish are wrapped in a damp cloth or paper and transported in a low temperature state. In addition, for example, by treating the shellfish with a biological feed such as phytoplankton at the time of purification after landing as described above, nutrients and taste components in the shellfish (hereinafter, both may be collectively referred to as nutrients). ) Has been practiced in the past to enhance the nutrition and maintain the freshness. As an example of a method for enhancing the nutrition of shellfishes during purification treatment, Japanese Patent Laid-Open No. 8-322420 discloses a bivalve shell that adjusts the nutrient content of the bivalve edible portion by feeding a predetermined artificial fine particle feed. A farming method is proposed.
[0004]
[Problems to be solved by the invention]
However, the conventional low-temperature transport method has a problem that it is difficult to control the temperature. It has also been frequently experienced that the freshness of shellfish is significantly reduced during transport due to the lack of strict temperature control, and that shellfish are also weakened or moribund. In addition, even in the case of low-temperature transportation, it is required to perform from landing to packing / shipping (start of transportation) promptly in case the transportation time is extended for some reason.
[0005]
On the other hand, the conventional nutrient enhancement method for storing nutrients in shellfish in preparation for transportation or the like has a problem that it takes time for nutrition enhancement. It takes several weeks for biological feeds such as phytoplankton to be metabolized via the digestive organs of shellfish to improve the state of shellfish. Even when the artificial fine particle feed according to the above publication is used, it takes about 5 days to adjust the nutrient content in the shellfish. In order to enable quick shipment after landing, there is a need for a method that can enhance nutrition in shellfish in a short time.
[0006]
Therefore, an object of the present invention is to provide a method for maintaining the freshness of shellfish, which can easily enhance nutrients in shellfish in a short time.
[0007]
[Means for Solving the Problems]
The present inventor paid attention to the fortification of shellfish with dissolved nutrients dissolved in water instead of the conventional solid feed. Conventionally, shellfish are known to absorb minerals dissolved in water to form shells, and the availability of dissolved minerals by shellfish has been suggested. Moreover, it is estimated that a part of the artificial fine particle feed of the above publication is dissolved in water. However, no specific report has been made yet regarding the absorption of dissolved nutrients by shellfish.
[0008]
The present inventor uses three kinds of bivalves, pearl oyster, scallop, and oyster, to investigate the absorption ecology of dissolved nutrients by shellfish, glutamic acid (glutamic acid), taurine (known as a taste component of shellfish) as nutrients We selected three types of amino acids, taurine) and glycine, and conducted experiments to confirm the absorption ecology of these dissolved amino acids. Divide the three 30 liter tanks into 4 test zones and put seawater. Glutamic acid, taurine and glycine are dissolved in the seawater of the 1st to 3rd test zones of each tank at a concentration of 2.7 μmol / g. The taurine group and glycine group were used, and for comparison, the fourth test group of each water tank was used as a control group with no amino acid added.
[0009]
The reason for setting the amino acid concentration in each test section to 2.7 μmol / g is that the amino acid concentration in seawater is slightly lower than the appropriate value of the amino acid concentration in the shellfish of the bivalve test specimen, This is to confirm uptake. In this experiment, taking into account the amino acids absorbed by shellfish and the excreted substances, the seawater in which the amino acids in each test zone were dissolved was replaced every 24 hours, and the amino acid concentration in the seawater during the experiment was kept constant. did.
[0010]
The first tank contains 20 pearl oysters in each test zone at a water temperature of 23.3 ° C, the second water tank contains 20 scallops in each test zone at a water temperature of 16.4 ° C, and the third water tank conducts tests at a water temperature of 22.5 ° C. 20 oysters were housed in the ward. The experiment was started by ventilating each tank with one air stone, and 5 individuals from each test section of each tank were picked up 24, 48, 72 and 96 hours after the start of the experiment. The amino acid concentration in the meat was measured. The experimental results of the pearl oyster, scallop and oyster are shown in the graphs of FIGS.
[0011]
The graph of FIG. 3 (A) shows the change in glutamic acid concentration in the pearl oyster shell of the first tank, and the graph of FIG. 3 (B) shows the change of taurine concentration in the pearl oyster shell of the taurine and control. The graph of FIG. 5C shows changes in glycine concentration in the pearl oyster shell of the glycine group and the control group. Each graph also shows the amino acid concentration (constant value) in the seawater for each test zone. As can be seen from FIG. 5A, the pearl oyster hardly takes in dissolved glutamic acid into the body. As can be seen from FIG. 5B, pearl oysters do not show statistically significant uptake of dissolved taurine. On the other hand, as shown in FIG. 5C, the pearl oysters actively take dissolved glycine into the body, and the concentration of glycine in the pearl oyster shellfish rapidly increases in a short time in the seawater where dissolved glycine is dissolved. 48 hours after the start of the experiment, the glycine concentration reached a maximum value of 35 to 40 μmol / g (about 6 to 8 times the concentration in the control group). That is, the pearl oyster has a selective uptake ability of dissolved glycine.
[0012]
4A, 4B, and 4C show changes in the concentrations of glutamic acid, taurine, and glycine in the scallop shell of the second tank. As shown in FIGS. 2A and 2C, scallops hardly take up dissolved glutamic acid into the body and do not show significant uptake of dissolved glycine. However, as shown in Fig. 5 (B), the concentration of taurine in scallop shellfish increased in a short time in seawater in which dissolved taurine was dissolved, and about 1.5 times (about approx. 60 μmol / g), which was approximately doubled (about 75 μmol / g) 96 hours after the start of the experiment. That is, scallops have the ability to selectively take up dissolved taurine.
[0013]
5A, 5B, and 5C show changes in the concentrations of glutamic acid, taurine, and glycine in the oyster shell of the third tank. As shown in FIGS. 4A and 4B, oysters do not show significant uptake of dissolved glutamic acid and taurine. However, as shown in FIG. 3C, the concentration of glycine in the oyster shellfish rapidly increased in a short time in seawater in which dissolved glycine was dissolved (approximately 4 in 48 hours after the start of the experiment compared to the control group). Twice, about 6 times in 72 hours). That is, oysters have the ability to selectively take up dissolved glycine.
[0014]
The rapid increase in the concentration in the body shown in the experimental results is not observed in the conventional feeding of food through the digestive tract, and therefore organs other than the digestive tract (hereinafter, sometimes referred to as non-digestive tract). It is thought to be due to absorption of dissolved amino acids from The details of the mechanism of absorption from non-digestive organs are unknown, but it is thought that respiratory organs such as shells of shellfish and sharks are involved in absorption. That is, from the experimental results of FIGS. 3 to 5, it was confirmed that bivalves selectively absorb dissolved amino acids from non-digestive organs depending on the type.
[0015]
Through further experiments, the present inventor confirmed that the above-mentioned selective increase in the body concentration of nutrients other than amino acids was observed, and the same increase in the body concentration of snails other than bivalves and freshwater shellfish. It was found that can be seen. By utilizing such a rapid increase in the body concentration in the shell meat due to the uptake of nutrients from the non-digestive organs, the nutrients in the shell meat can be enhanced in a short time. The present invention has been completed as a result of further experimental studies based on this finding.
[0016]
Referring to the embodiment of FIG. 1, the freshness maintaining method for shellfish according to the present invention is obtained by dissolving glycine 3 in water 2 to obtain a freshness maintaining solution 5, and the freshness maintaining solution 5 contains pearl oysters or oysters that are shellfish 1. It is soaked for 24 to 96 hours to increase the concentration of glycine 3 in the shellfish.
[0017]
In addition, the method for transporting shellfish according to the present invention involves immersing oyster oysters or oysters that are shellfish 1 in a freshness maintenance solution 5 in which glycine 3 is dissolved in water 2 before transport for 24 to 96 hours. Increased body concentration.
[0018]
Shellfish 1 having a selective uptake ability of dissolved glycine 3 , such as pearl oysters and oysters , absorbs glycine 3 from organs other than the digestive tract. The time required for soaking is 24 to 96 hours. In soaking for 24 hours or less, it may be difficult to sufficiently increase the concentration of nutrient 3 in the shellfish. This is because the concentration of nutrient 3 in the body is considered to reach a maximum value. The shell meat includes all parts of the shellfish other than the shell.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment in which glycine is dissolved as nutrient 3, in this case dissolved in seawater 2 to obtain a freshness-maintaining liquid 5 of the present invention. The shellfish 1 is, for example, pearl oyster or oyster having the ability to take up dissolved glycine by non-digestive organs, and the shellfish 1 is placed in the freshness maintenance solution 5 of FIG. 1 for 24 to 96 hours (preferably 48 hours or more for pearl oysters, If soaked for 72 hours or more, the concentration of glycine in the shellfish can be rapidly increased to a higher concentration than that obtained by feeding the feed through the digestive tract (see the experimental results in FIGS. 3 and 5).
[0020]
In FIG. 1, the nutrient 3 is dissolved in the seawater 2, but in the case of freshwater shellfish 1, the nutrient 3 is dissolved in the freshwater 2 to prepare the freshness maintenance liquid 5 of the present invention. Further, the water 2 is not limited to natural water, and as artificial breeding water, for example, seawater 2 can be artificial seawater, and freshwater 2 can be sterilized water.
[0021]
The concentration of the nutrient 3 in the freshness maintenance liquid 5 is not particularly limited as long as the shellfish 1 can be absorbed from the non-digestive organs, and can be a relatively low concentration of, for example, about 2.7 μmol / g. Even if the dissolved concentration of the nutrient 3 in the freshness maintenance solution 5 is low, the concentration of glycine in the shellfish of the shellfish 1, for example, is adjusted to the glycine concentration in the freshness maintenance solution 5 by adjusting the time of immersion in the freshness maintenance solution 5. In comparison, it can be increased to about 4 to 8 times. Therefore, in the present invention, it is expected that the concentration in the body of the nutrient 3 in the shellfish can be efficiently and economically increased by using the freshness maintaining solution 5 in which the dissolved concentration of the nutrient 3 is relatively low.
[0022]
The time for immersing the shellfish 1 in the freshness maintaining solution 5 can be adjusted according to the types of the shellfish 1 and the nutrient 3. In this case, a graph showing the relationship between the soaking time and the concentration in the shellfish as shown in FIGS. 3 to 5 according to the types of the shellfish 1 and the nutrient 3 is prepared, and the nutrient 3 in the shellfish is determined as the desired body concentration. The soaking time can be determined experimentally.
[0023]
[Experimental example]
Using a freshness maintaining solution 5 in which the nutrient (glycine) 3 shown in FIG. 1 was dissolved and using a oyster as the shellfish 1, an experiment for confirming the freshness maintaining effect according to the present invention was conducted. In this experiment, a oyster immersed for 24 hours in freshness-maintaining liquid 5 having a glycine concentration of 2.7 μmol / g and a oyster immersed for 24 hours in seawater without glycine for control were immersed in fresh water. And compared mortality over time.
[0024]
Referring to the graph of FIG. 2 showing the experimental results, neither individual died until 5th day, but about 80% of the target oysters died after 6th day. On the other hand, the oysters immersed in the freshness maintenance solution 5 of the present invention have a mortality rate of only about 20% even on the sixth day, and it can be confirmed that the survival rate is excellent in a severe environment of breeding in fresh water. It was. In addition, it took another 3 days for the mortality of the oysters immersed in the freshness maintenance solution 5 of the present invention to reach 80%. From this, it was confirmed that the freshness-maintaining liquid 5 of the present invention can maintain the freshness of shellfish for a long period of time by immersion for an extremely short time of 24 hours.
[0025]
Although the details of the mechanism by which an increase in the concentration of glycine in shellfish leads to the maintenance of freshness are unknown, gluconeogenesis, in which amino acids are decomposed for energy production as a general metabolic pathway when sugars and proteins are deficient ) Is known (see, for example, Rikio Shinohara et al. “Easy to understand biochemistry-for understanding of diseases and nutrition-” Yodogawa Shoten (first edition on September 20, 1997) pp88-91), In this experiment, it is considered that glycine was used as an energy source by increasing the concentration of glycine in the body, and the freshness could be maintained for a long time.
[0026]
The present invention can be widely applied to shellfish capable of taking up dissolved nutrients from non-digestive organs, and the freshness of shellfish can be reduced by a very simple method of immersing shellfish in a freshness maintenance solution in which nutrients are dissolved. Can be prevented. In addition, since the concentration of nutrients in the shellfish can be increased only by immersing in the freshness-maintaining liquid for a short time of about 24 to 96 hours, it can be said to be a freshness-maintaining method with immediate effect. Furthermore, as described later, the present invention can be expected to be used in a wide range of fields including transportation of shellfish and artificial culture, and can be said to be a practical means for increasing the commercial value of shellfish.
[0027]
Thus, the provision of “a method for maintaining the freshness of shellfish that can easily enhance nutrients in shellfish in a short time”, which is an object of the present invention, can be achieved.
[0028]
【Example】
The present invention can be effectively used when the shellfish 1 is landed and transported. For example, the shellfish 1 is immersed in the freshness maintenance liquid 5 for a required time before being transported after landing and the concentration of the nutrient 3 in the shellfish is increased. As described above, for example, if oysters or pearl oysters are immersed in the freshness maintenance solution 5 in which glycine is dissolved for about 24 to 48 hours, the in-vivo concentration of glycine that can be used as an energy source can be easily increased. In addition to the case, the freshness of the shellfish can be suppressed even when the transportation time is extended for some reason or when strict temperature control is not possible.
[0029]
The present invention can also be expected to be used for artificial culture of shellfish. In conventional farms, the nutritional status of shellfish has been unstable due to the dependence on the natural feed environment. There were no effective improvement measures against sudden changes in the environment, and the vitality of shellfish sometimes fluctuated due to the quality of the natural environment. Although attempts have been made to use artificial fine particle feeds or the like, it is not easy to increase the concentration of specific nutrients in the body. According to the present invention, the concentration of a specific nutrient in shellfish can be increased by an extremely simple process, which can be said to have a great practical meaning. For example, the mortality rate of shellfish 1 is reduced by immersing shellfish 1 in the freshness maintenance solution 5 of the present invention in which glycine is dissolved and increasing the concentration of glycine in the season when shellfish 1 is easily consumed, such as during the spawning activity period. Can be expected.
[0030]
Although scallops do not absorb dissolved glycine from non-digestive organs, the body concentration of taurine, known as a taste component, can be increased by immersing it in the freshness maintaining solution 5 in which taurine is dissolved. In conventional shellfish farming, it has been pointed out that the amino acid composition and content in shellfish vary depending on the season and the like, and the flavor varies depending on the shipping time. In the cultivation of scallops, if the taurine concentration in the scallop is increased with the freshness maintaining solution 5 of the present invention, the seasonal variation of the flavor of shellfish can be minimized and the effect of increasing the food value of shellfish can be expected. In the case of pearl oysters, for example, during the operation of pearl nucleation, the glycine body concentration is increased by immersing in the freshness-maintaining liquid 5 of the present invention for the required time, so that the oyster oysters are expected to recover their physical strength early after surgery. it can.
[0031]
【The invention's effect】
As described above, the freshness maintaining method and transporting method of the shellfish according to the present invention includes dissolving glycine in water to obtain a freshness maintaining solution, and immersing the pearl oyster or oyster in the freshness maintaining solution for 24 to 96 hours. Since the concentration of glycine in the body is increased, the following remarkable effects are exhibited.
[0032]
(I) The fall of the freshness of shellfish can be prevented effectively by the very simple process which only immerses shellfish in the freshness maintenance liquid which melt | dissolved the nutrient for the required time.
(B) a body concentration of nutrients in immersion for a short time can be increased significantly, Ru can be said that the Freshness method with immediate effect.
(C) By immersing the shellfish in a freshness-maintaining liquid before landing and transporting the shellfish, it is possible to prevent a decrease in freshness of the shellfish during transportation and to reduce the mortality rate.
(D) In the case of pearl oysters, rapid recovery of physical strength after surgery can be expected if the glycine concentration in the glycine is increased with a freshness maintenance solution during pearl nucleus surgery.
(E) It can be expected that the concentration of specific nutrients in shellfish can be increased, the flavor of shellfish can be kept constant regardless of the season, and the food value of shellfish can be increased.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an embodiment of the present invention.
FIG. 2 is a graph showing a freshness maintaining effect according to the present invention.
FIG. 3 is a graph showing the selective absorption ability of dissolved glycine by pearl oysters.
FIG. 4 is a graph showing the selective absorption ability of dissolved taurine by scallops.
FIG. 5 is a graph showing the selective absorption ability of dissolved glycine by oysters.
[Explanation of symbols]
1 ... Shellfish (Ako-gai or oyster) 2 ... Water (freshwater, seawater)
3 ... Nutrient (glycine) 5 ... Freshness maintenance solution

Claims (6)

A method for maintaining the freshness of shellfish in which glycine is dissolved in water to make a freshness maintenance solution, and oyster oysters or oysters are immersed in the freshness maintenance solution for 24 to 96 hours to increase the concentration of glycine in shellfish. The freshness maintenance method of Claim 1 WHEREIN: The freshness maintenance method of shellfish which raises the density | concentration in a glycine in the shellfish of a pearl oyster or a oyster by 48 times or more compared with the case where it does not immerse. The freshness maintenance method of Claim 1 or 2 WHEREIN: The freshness maintenance method of the shellfish which makes the glycine density | concentration in the said freshness maintenance liquid below the appropriate value of the shell internal body concentration of a pearl oyster or a oyster. A method of transporting oyster or oyster is shellfish, transport of glycine before transport the oyster or oyster in freshness liquid dissolved in water and immersed 24-96 hours made by increasing glycine body concentration in shellfish meat and shellfish Method. 5. The method for transporting shellfish according to claim 4, wherein the glycine concentration in the oyster or oyster shell is not soaked by the soaking for 48 hours as compared to a case where it is not soaked. 6. The method for transporting shellfish according to claim 4 or 5, wherein the glycine concentration in the freshness maintenance liquid is not more than the appropriate value of the concentration in the shell of pearl oyster or oyster .

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