JP2002300819A - Method for accelerating recovery of discolored cultured laver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate the recovery of a discolored laver caused by the lack of nitrogen and phosphorus in seawater, and shortening the growing period of the cultured laver. SOLUTION: This method for accelerating the recovery of color and gloss of the laver is provided by immersing the discolored cultured laver or a culturing tool attached with the discolored cultured laver in a treating solution obtained by adding and dissolving 0.5-20% sodium chloride, 0.015-0.5% nitrogen and 0.0015-0.15% phosphorous in seawater and then adjusting pH as 1.5-4.0 by adding an acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for promoting the recovery of color loss of laver generated during the cultivation of laver.

[0002]

2. Description of the Related Art In seaweed cultivation, seaweed spores are attached to a seaweed net to raise seedlings until the buds become about 2 to 3 cm in length. The shoots are harvested after the growing stage. In the production process of the cultured seaweed, in relation to the situation of the fishing grounds and the production plan, the seedlings that have completed the seedling raising stage are once withdrawn from the seawater together with the seaweed net, dehydrated and frozen, and stored at an appropriate time. In some cases, the thawed seaweed net is overhanging in seawater again.

However, in recent years, due to environmental changes and abnormal breeding of diatoms, the nitrogen and phosphorus contents required for the growth of laver in the seawater in the sea area of the laver farming and fishing ground have been abnormally reduced, and the normal growth of the laver leaf body has occurred. And the color of the laver changes from black to yellow, a phenomenon commonly called color fading has come to occur frequently. Conventionally, the discoloration phenomenon of the cultured seaweed as described above usually occurred at the time of plucking. However, in recent years, especially in the Ariake Sea of Kyushu and the like, it has also occurred at the seedling raising stage before the above-mentioned frozen storage and before the harvesting, which has had a significant effect on laver production.

[0004] As described above, when the nitrogen and phosphorus contents in seawater decrease so as not to be suitable for the production of laver and the seaweed discolors, the nitrogen and phosphorus contents in the seawater are naturally reduced. If it does not recover until it is in a state suitable for production under normal conditions, it will not return to a normal color. Therefore, if the seaweed discolors, wait for the nitrogen and phosphorus content to recover to a level suitable for production in a natural state while maintaining the seaweed net, or temporarily remove the seaweed net from the sea. It has to be pulled up, dehydrated, frozen and stored, and wait until the nitrogen and phosphorus contents in the seawater return to a normal state and the sea condition improves, then re-extend the laver net. However, while keeping the laver net,
If the nitrogen and phosphorus content in the seawater recovers naturally to an amount suitable for production and waits until the sea condition improves, if the discoloration period is long, the seaweed will have a normal color and luster even if the sea condition improves It will take quite a few days to get back to. Also, once the seaweed net has been pulled out of the sea together with the seaweed net and stored frozen, wait until the sea condition improves, and even if the seaweed net is overhanged, it will take a considerable number of days to return to normal color and luster. Will take. As described above, once the seaweed is discolored, it takes a long time until the color is restored to a normal color and luster, and the production efficiency is reduced.

[0005] Conventionally, in order to recover the discoloration of laver due to the shortage of nitrogen and phosphorus in the seawater as described above, it has been practiced to spray nutrients containing nitrogen and phosphorus into the seawater in the sea area of the laver aquaculture fishing ground. We have been working but have had little effect. In addition, conventionally, in seaweed cultivation, an acid treatment has been performed in order to control diseases of seaweed and diatoms and other algae to increase the production amount. It is known that by performing this acid treatment, diseases such as diatoms and other algae and red rot are controlled, and the color and luster of the nori leaf are improved and the production amount is increased. For example, Japanese Unexamined Patent Publication (Kokai) No. 62-21784 discloses a liquid fertilizer which is also used as an algicide for laver cultivation, comprising an acid buffer containing dilute hydrochloric acid as a main component and nitrates, ammonium salts and phosphates. In the publication, a solution containing sulfur-containing amino acids or the like as a main component contains phosphates such as sodium phosphate and potassium phosphate as nutrients of laver, nitrates such as sodium nitrate and potassium nitrate, and citric acid and malic acid. , A growth promoter containing an organic acid such as phytic acid and saccharides such as glucose and fructose is disclosed in
No. 271985 describes an algae healthy growth promoting substance containing salts such as calcium chloride and calcium oxide and acids such as citric acid, malic acid, fumaric acid and phosphoric acid. These are intended to control the algae and diseases by acid treatment, and at the same time, by using nutrients in combination, to promote the improvement of the quality of seaweed and healthy growth. However, these conventional acid treatments are carried out for the purpose of controlling weeds and diseases with acids, improving the quality with nutrients, and promoting growth.In the past, when the seaweed was discolored, However, no treatment has been performed on nori to promote its recovery, and no effective method has been proposed. Therefore, if the seaweed has discolored, wait until the nitrogen and phosphorus content in the seawater has recovered to an amount suitable for laver production and the sea condition has improved, and the discoloration of the seaweed will recover naturally The fact is that they have been waiting for. A report from the Ariake Fisheries Experimental Station in March 1989, entitled "Study on the Use of Hydrogen Ion Concentration Changes in Nori Culture," states that inorganic acid nitrogen (DIN) and inorganic phosphorus ( Although it has been reported that the absorption of nutrients such as PO ₄ -P) into laver is improved, it has been reported that the absorption of nitrogen and phosphorus decreases immediately after acid treatment as compared with no treatment. There is no description about the effect of promoting the recovery of the dropped seaweed.

[0006]

As described above, conventionally,
For seaweed discoloration due to lack of nitrogen and phosphorus in seawater, there is no known effective method to promote the recovery of seaweed. However, it was necessary to wait for natural recovery, and the cultivation period was long, and reduction in production efficiency due to discoloration was inevitable. In view of the above, an object of the present invention is to provide a method of promoting the recovery of discolored laver, thereby shortening the growing period and improving the production efficiency.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, the color of cultured seaweed that has been discolored due to lack of nitrogen and phosphorus in seawater has been restored. In the course of the process, it was found that the treatment of the laver with an acid treatment agent to which inorganic salts were added significantly accelerated the recovery of the color and luster of the laver, and completed the present invention.

[0008] That is, the method of the present invention for promoting the recovery of discolored cultured seaweed is carried out by dissolving the discolored cultured seaweed or the culture implement having the discolored cultured seaweed in seawater for 0.5 to 20 minutes.
% Of inorganic salts, dissolve and add acid
It is characterized in that it is immersed in a treatment liquid in which H is adjusted to 1.5 to 4.0. The treatment liquid may contain various nitrogen sources and phosphorus sources as nutrients, 0.015 to 0.5% as nitrogen and 0.0015 to 0.15% as phosphorus. Further, as the inorganic salts, sodium chloride, magnesium chloride, calcium chloride, potassium chloride, sodium sulfate, magnesium sulfate, potassium sulfate, iron chloride, iron sulfate and the like can be used. it can. In the present invention, "%" indicating the concentration of each component in the treatment liquid is weight / volume% based on seawater.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The method for accelerating the recovery of discolored cultured seaweed according to the present invention is described, for example, by adding the above-mentioned inorganic salts to seawater pumped from a seaweed aquaculture area.
~ 20% added and dissolved, and if necessary, a nitrogen source or a phosphorus source as a nutrient is added thereto at a predetermined concentration so that the pH is in the range of 1.5 to 4.0. An acid is added and dissolved to form a treatment liquid, and the treated seaweed is immersed in the treated liquid to perform treatment.

The inorganic salts include sodium chloride,
Magnesium chloride, calcium chloride, potassium chloride, sodium sulfate, magnesium sulfate, potassium sulfate, iron chloride, iron sulfate and the like may be used alone or in combination of two or more. In the present invention, the inorganic salts are not used as nutrients for promoting the growth of laver in a conventional acid treatment agent, but promote the recovery of the color of the laver that has been discolored when used in combination with an acid. . As the inorganic salts, it is preferable to use salt in view of solubility in seawater, handleability, cost, and the like. The amount of the inorganic salt added to the treatment liquid is 0.5 to
20%. If the addition amount of the inorganic salts is less than 0.5%,
Since the effect of promoting the recovery of discolored laver is small, and if the amount of the added inorganic salt is more than 20%, the laver may be damaged, it is preferable to be within the above range.

As the above-mentioned acid, any of various inorganic acids, carboxylic acids, organic phosphoric acids and the like conventionally used for acid treatment of cultured laver can be used. Examples of the inorganic acid include sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid and the like. In the case of phosphoric acid, it also serves as a phosphorus source as a nutritional component. The carboxylic acids include malic acid, citric acid, acetic acid, lactic acid, fumaric acid, gluconic acid, maleic acid,
Malonic acid, formic acid, tartaric acid, acrylic acid, crotonic acid, oxalic acid, succinic acid, glutaric acid and the like can be used. Further, phytic acid, metaphosphoric acid, polyphosphoric acid and the like can be used as the organic phosphoric acid. These acids may be used alone or in combination of two or more. These acids have a pH of the processing solution of 1.5 to
It is added in such an amount as to be in the range of 4.0, but the pH of the treatment liquid is adjusted so as not to damage the nori leaf as described below.
It is appropriately adjusted in consideration of the influence on the laver leaf body according to the processing method and the processing time, and the pH of the processing solution is higher when the processing time is longer, and the pH is higher when the processing time is shorter. Set lower.

The nutrient nitrogen sources include ammonium chloride, ammonium nitrate, ammonium sulfate,
Examples thereof include ammonium salts such as ammonium phosphate, nitrates such as sodium nitrate and potassium nitrate, urea, amino acids and the like, and they can be used alone or in combination of two or more. The amount of addition of these nitrogen sources to the processing solution is 0.015 to 0.5% as nitrogen.
If the amount of nitrogen to be added is less than the above range, the effect of the addition cannot be expected, and even if it exceeds the above range, no further improvement in the effect can be seen. Further, as a phosphorus source, phosphoric acid, ammonium phosphate, sodium phosphate,
Potassium phosphate, sodium polyphosphate, potassium polyphosphate, sodium metaphosphate, potassium metaphosphate,
Phytic acid and the like can be mentioned, and they can be used alone or in appropriate combination of two or more kinds. The amount of these phosphorus sources added to the processing solution is 0.0015 to
0.15%. If the amount of phosphorus to be added is less than the above range, the effect of addition cannot be expected, and even if it is added beyond the above range, no further improvement in the effect can be seen.

Further, the above-mentioned treatment liquid may contain
Known nutrient components including sugars, amino acids and the like, as well as decomposed products of plants and animals such as waste liquids during the production of corn starch can also be added.

There is no particular limitation on the method of treating color-washed laver with the above-mentioned treatment liquid, and known acid treatment methods such as a so-called immersion treatment, a short-time treatment with a mogul boat or the like, and a pass-through treatment. The same processing method as described above can be employed. In the immersion treatment, the treatment liquid is stored in a vessel such as a treatment tank on a ship, and a culture tool such as laver or a laver net to which laver is attached is dipped in the treatment liquid. In the case of a method that requires a relatively long treatment time, such as this immersion treatment, the concentration of the inorganic salts to be added to the treatment liquid should be as low as 0.5 to 5% and the pH should be 1.7 or more. preferable. The processing time of this soaking process may be about 2 to 15 minutes in a normal case.
In addition, the method called processing by mogul boat or through processing is carried out in a short time by immersing the ship under a nori culture net and passing the processing solution stored in the processing tank on the ship under the nori net. In the case of such a short-time treatment, the concentration of the inorganic salts added to the treatment solution is 5 to 20%.
In this case, the pH can be set higher than that in the immersion treatment, and the pH of the treatment liquid can be reduced to about 1.5. The processing time in the case of the processing by the mogul boat or the through processing is usually about 10 seconds to 2 minutes.

The treatment of the seaweed that has been discolored as described above is performed at a stage where the insufficient nitrogen and phosphorus content in the seawater recovers in a natural state, and the color and luster of the seaweed recovers accordingly. It is effective, which promotes the restoration of the color and luster of the laver. For example, after the laver has been discolored, continue to keep the laver net and wait until the nitrogen and phosphorus contents are suitable for production in a natural state, and then process at the stage where the laver recovers, or After the seaweed has faded, once the seaweed net is pulled out of the sea, dehydrated and frozen and stored, wait for the nitrogen and phosphorus content in the seawater to return to a normal state and improve the sea condition After the seaweed net is overhanged again, the treatment is performed at the stage after a lapse of a few days. Further, after the above processing, the same processing may be repeated at predetermined intervals, for example, at intervals of several days to one week.

[0016]

EXAMPLE (Experiment 1) Using decolorized and dried frozen seaweed leaves from the Ariake Sea of Kyushu, containing 0.2 mg / L of nitrogen and 0.02 mg / L of phosphorus after returning to freezing. Cultured in artificial seawater. In the meantime, the seaweed leaf bodies were washed twice on the third day after freezing and one week after the freezing, with the treatment solution of each test group in which the organic acids, salt, nitrogen, phosphorus, etc. shown in Table 1 were added and dissolved in artificial seawater. Processed. In the treatment method using the treatment liquid, the laver leaf taken out from the artificial seawater was immersed for 5 minutes in the case of the treatment liquids of Examples 1 to 5 and Comparative Examples 2 to 4, and Examples 6 to 10 and Comparative Example 5 In the case of the treatment liquids of Nos. To 7, they were immersed for 20 seconds and returned to artificial seawater again after the treatment. Nori leaf bodies having a size of about 5 cm were used in each test group. The culture temperature is 10 ° C and the light and darkness is 1
The cycle was two hours. The amount of seawater used for culture per test plot was 500 ml, and was replaced every other day. During this period, the color of the nori leaf was observed, and the color return state over time was examined. The results are shown in Table 1. The color of the nori leaf body is visually determined based on the color strength of the nori leaf body of the untreated test plot at the time of each judgment, and the more + in the table, the deeper the leaf color is Is shown. The lactic acid used was 80% by weight.

[0017]

[Table 1]

As shown in Table 1, in Examples 2 and 3, the color of the laver was clearly improved on the day after the treatment as compared with the untreated or the treatment of the comparative example, and the effect of improving the discoloration state was observed. Therefore, in Example 4, a slight effect was observed on the day after the treatment. After the second day, the comparative example also showed some effects, but was inferior to the examples. 2
After the second treatment, the difference in the effect of improving color fading between the example and the comparative example became more remarkable. Further, among the examples, a higher effect of improving discoloration was observed when nitrogen and phosphorus were added.

(Experiment 2) In the same manner as in Experiment 1, the seaweed leaves that had been dehydrated and frozen were used. After reconstitution, they were cultured in artificial seawater. With the treatment solution of each test group in which salt, nutrients, etc. were added and dissolved,
The nori leaf was treated twice on the third day after freezing and one week after that, and the color of the nori leaf was observed in the same manner as in Experiment 1 to examine the color return state over time. The results are shown in Table 2. In the treatment method using the treatment liquid, laver leaves taken out from artificial seawater were used in Examples 11 to 16 and Comparative Examples 9 to 14.
In the case of the treatment solution of Example 17, the sample was immersed for 5 minutes.
In the case of the treatment liquids of No. 9 and Comparative Examples 15 to 17, they were immersed for 20 seconds and returned to artificial seawater again after the treatment. In addition, "times" about the acid treatment agent and the laver extract described in Table 2 is the dilution ratio of the acid treatment agent and the laver extract in the treatment liquid (artificial seawater).

[0020]

[Table 2]

As shown in Table 2, in Example 12, the color of the laver was clearly improved on the day after the treatment as compared with the untreated or the treatment of the comparative example, and the effect of improving the discoloration was observed. Example 13 also showed some effects the day after the treatment. After the second day, the comparative example also showed some effects, but was inferior to the examples. 2
After the second treatment, the difference in the effect of improving color fading between the example and the comparative example became more remarkable. Furthermore, among the examples, a higher discoloration improvement effect was observed when a laver extract containing nitrogen and phosphorus was added.

As is evident from the results in Tables 1 and 2, in the examples in which the nori leaf was washed out by discoloration of a nori leaf body in a treatment solution obtained by adding salt to an acid or an acid treatment agent, the leaves were compared with the case of no treatment. It can be seen that the color of the body becomes dark and the recovery of the discolored laver is promoted. Further, by using a nutritional component in addition to the acid, the acid treating agent and the salt, the recovery of discoloration is further promoted. On the other hand, when the treatment is performed using only the acid or the acid treatment agent and the treatment liquid obtained by simply adding the nutrient to the acid or the acid treatment agent,
There is no noticeable difference in the color of the nori leaf body compared to the case of no treatment,
It is clear that a simple acid treatment or a combination of an acid treatment and a nutrient can hardly provide the effect of facilitating the recovery of discoloration.

[0023]

As described above, according to the present invention, the recovery of discoloration of seaweed is promoted by immersing the seaweed in an acid-treated solution to which inorganic salts have been added in the process of recovering the discolored cultured seaweed. Thus, the recovery period until the discolored laver becomes a normal color is shortened, and a decrease in the production efficiency of cultured laver due to discoloration can be suppressed.

Continuation of the front page (72) Inventor Hiroshi Tsubota 17-1 Fukakusa Shinmonjochocho, Fushimi-ku, Kyoto-shi, Kyoto Prefecture Familia Heights Kyoto Fushimi Stage I 911 F-term (reference) 4B019 LC03 LK01 LP02 LT01

Claims (4)

[Claims] The discolored cultured seaweed or a culture tool to which the discolored cultured seaweed is attached is dissolved in seawater by adding 0.5 to 20% of inorganic salts, and an acid is added to adjust the pH to 1. 5-
A method for promoting recovery of discolored cultured seaweed, which is immersed in a treatment solution adjusted to 4.0. 2. The method according to claim 1, wherein the treatment liquid contains 0.015 to 0.5% of nitrogen and 0.0015 to 0.15% of phosphorus. Method. 3. The inorganic salt is at least one selected from the group consisting of sodium chloride, magnesium chloride, calcium chloride, potassium chloride, sodium sulfate, magnesium sulfate, potassium sulfate, iron chloride and iron sulfate. 3. The method for accelerating the recovery of cultured seaweed that has faded according to 1 or 2. 4. The method according to claim 1, wherein the inorganic salt is salt.