JP2000239302A - Extraction of fucoidan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extraction method that gives fucoidan of a relatively high average molecular weight with no problem of corrosion of the facility and the like in the production installation. SOLUTION: When fucoidan is extracted from a seaweed, Cladosiphon okamuranus, an organic acid is used in an amount of 1-100 g/1,000 g of the seaweed and the pH in the extraction process is adjusted in the range from 2 to 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for extracting fucoidan from Okinawa mozuku. More specifically, the present invention relates to a fucoidan extraction method capable of efficiently obtaining fucoidan having an average molecular weight within a desired range without causing a problem such as corrosion in a production facility.

[0002]

2. Description of the Related Art Conventionally, fucoidan contained in Okinawa mozuku has an excellent anticholesterol effect, blood clarification effect,
Since it has pharmacological effects such as an anticoagulant effect, an anticancer effect, an anti-AIDS virus effect, and an antigastric ulcer effect, it has been desired to extract it efficiently.

[0003] Japanese Patent Application Laid-Open No. 10-70970 discloses that from Mozuku, hot water at 60 to 100 ° C is used and the weight average molecular weight is 50,000 to 5 under conditions of 30 minutes to 3 hours.
A hot water extract having a neutral sugar content of 50-90% and a sulfur content in the range of 3-17%,
For example, a method for extracting a hot water extract containing fucoidan is disclosed.

[0004] Further, Japanese Patent Application Laid-Open No. 10-165114, and published publication, Applied Glycoscience, Vol. 43, No. 2, p.
143-148, (1996) (published on June 30, 1996) using an inorganic acid (concentration: 0.2 N) such as hydrochloric acid or sulfuric acid as an extractant from cultured Okinawa mozuku, at room temperature for 24 hours. A method of extracting fucoidan over a period of time is disclosed.

Further, Japanese Patent Application Laid-Open Nos. 61-57519 and 61-5752019 disclose that a highly viscous fucoidan-containing solution extracted from seaweed using water, warm water or hydrochloric acid contains β-. A method of dissolving 1,3-glucanase or protease to decompose a high-viscosity imparting substance contained in a fucoidan-containing solution to produce a low-viscosity fucoidan-containing solution, or further producing fucoidan using an ultrafiltration membrane A method for doing so is disclosed.

Further, JP-A-6-62852, JP-A-7-59563 and JP-A-7-59564.
Japanese Patent Application Publication No. JP-A-2003-177334 discloses a fucoidan-degrading enzyme extracted from sea urchins, which has an optimum pH of about pH 3 to 3.5, an optimum temperature of about 50 to 55 ° C., and SDS-polyacrylamide gel electrophoresis. Fucoidan-degrading enzyme having a molecular weight of about 23,000 (JP-A-6-62852),
Is fucoidan-degrading enzyme having a pH of about 4 to 4.5 and an optimum temperature of about 60 ° C. (JP-A-7-59563), and an optimum pH of about pH 3 to 4.0 and an optimum temperature of about Fucoidan-degrading enzyme at around 45 ° C.
No. 59564) discloses a method for producing fucoidan.

[0007]

However, according to the production method disclosed in JP-A-10-70970, the yield of fucoidan is as low as less than 1% based on the raw material used, and
In addition, there was a problem that the content of fucose (uronic acid) contained in fucoidan was small.

Further, in the production method disclosed in Japanese Patent Application Laid-Open No. H10-165114, etc., since a highly corrosive strong acid is used as an extractant, there is a problem that the production equipment is easily corroded. Of course, by using an inorganic material having high corrosion resistance, corrosion of manufacturing equipment can be prevented to some extent, but an inorganic material having high corrosion resistance is extremely expensive or poor in workability. And so on, which was economically disadvantageous. Further, fucoidan obtained by the production method disclosed in the publication and the like has a molecular weight that is too high, and a desired molecular weight, for example, 10,000 to 5,000.
It was not easy to set the value within the range of 0000.
In addition, for example, in order to typically show an anti-AIDS virus action, the average molecular weight of fucoidan is set to 100,000 to 20
It is known that a value in the range of 0.000 is preferred, and similarly, to typically exhibit anti-gastric ulcer action,
It is known that it is preferable to set the average molecular weight of fucoidan to a value of about 200,000. Furthermore, when a strong acid is used as an extractant, the obtained fucoidan
Ultimately, it is necessary to neutralize using a strong base, and thus, there are problems that the number of production steps increases and the amount of impurities contained increases.

In the production methods disclosed in JP-A-61-57519 and JP-A-61-5752019, when hydrochloric acid, which is a strong acid, is used as an extractant, JP-A-10-165114. In the case where water or warm water (40 ° C., 14 hours) is used as an extractant, there are problems such as corrosiveness and molecular weight similar to those described in
There was a problem that the extraction efficiency was extremely low as in the case of Japanese Patent Application Publication No. 0-70970.

Further, JP-A-6-62852, JP-A-7-59563 and JP-A-7-59564.
If the production method using the fucoidan-degrading enzyme disclosed in Japanese Patent Application Publication, no corrosive problem of the production equipment is observed, but only using such fucoidan-degrading enzyme, the yield of fucose contained in fucoidan is low. The problem was seen.

Therefore, the inventors of the present invention diligently studied the above problems, and found that by performing swelling treatment before enzymatic treatment, the production equipment was not corroded and fucoidan was not excessively decomposed, and The inventors have found that a high extraction rate can be obtained, and have completed the present invention. That is, an object of the present invention is to provide a method for extracting fucoidan using an enzyme capable of efficiently obtaining fucoidan having an average molecular weight within a desired range without causing a problem such as corrosion in a production facility.

[0012]

SUMMARY OF THE INVENTION The present invention is a method for extracting fucoidan from Okinawa mozuku, wherein an organic acid is used as an extractant and the pH of the extraction step is adjusted to a value within the range of 2 to 6. Features. By using an organic acid in this way, there is no problem of corrosiveness to production equipment or molecular weight of fucoidan, and further, there is no need to neutralize with a strong base. Further, since the pH in the extraction step is limited to a predetermined range, excellent extraction efficiency can be obtained.

In carrying out the extraction method of the present invention, the amount of the organic acid used is preferably set to a value within the range of 1 to 100 g per 1000 g of Okinawa mozuku. By thus limiting the amount of the organic acid used, excellent extraction efficiency of fucoidan can be obtained, and the amount of impurities contained can be reduced.

In carrying out the extraction method of the present invention, the organic acid is citric acid, acetic acid, propionic acid, butyric acid,
It is preferably at least one compound selected from the group consisting of valeric acid, stearic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, phthalic acid, glycolic acid, and benzoic acid. By using such kind of organic acid, excellent extraction efficiency can be obtained, and there is no problem of corrosiveness to production equipment and molecular weight of fucoidan.

In carrying out the extraction method of the present invention, the temperature of the extraction step is preferably set to a value within the range of 25 to 95 ° C. By limiting the extraction temperature in this way, excellent extraction efficiency is obtained, and the production control is also improved.

In carrying out the extraction method of the present invention, the extraction time in the extraction step is preferably set to a value within the range of 0.5 to 72 hours. By limiting the extraction time in this way, excellent extraction efficiency is obtained, and the economy is improved.

In carrying out the extraction method of the present invention, it is preferable to use at least one inorganic acid selected from the group consisting of formic acid, hydrochloric acid, sulfuric acid and nitric acid, together with the organic acid. As described above, by using the inorganic acid in combination, excellent extraction efficiency can be obtained, and economic efficiency can be improved. In addition, since the organic acid and the inorganic acid are used in combination, the amount of the inorganic acid used is reduced, so that the problems of corrosiveness to production equipment and the molecular weight of fucoidan are also reduced.

In carrying out the extraction method of the present invention, the average molecular weight of fucoidan is adjusted to 10,000 to 1.0.
It is preferable that the value be in the range of 00,000. By limiting the average molecular weight of fucoidan in this way,
For example, it can exhibit excellent anti-AIDS virus action and anti-gastric ulcer action.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. It should be noted that the following description is merely an outline to the extent that the extraction method of the present invention can be understood. Therefore, the present invention is not limited only to the following description.

[First Embodiment] The first embodiment is a method for extracting fucoidan which sequentially includes the following steps (1) to (3). (1) Pretreatment process of Okinawa mozuku (2) Extraction process of fucoidan (3) Post-treatment process of fucoidan

(1) Pretreatment Step of Okinawa Mozuku In extracting Okinawa fowl from fucoidan,
In order to improve the extraction efficiency and reduce the amount of impurities, it is preferable to perform pretreatment (thawing, desalting, and crushing).

Thawing and desalting Okinawa mozuku (cultured and natural Okinawa mozuku)
After harvesting, it is often salted or refrigerated in order to improve the storage stability. Therefore, it is generally preferable to desalt or thaw in the pretreatment step. Specifically, after washing the surface salt with tap water, for example, 10
It is preferable to immerse the okinawa mozuku in a 00 liter container at a rate of 250 kg while flowing water for 0.5 to 5 hours.

Crushing In order to increase the extraction efficiency, it is preferable to crush Okinawa mozuku into small pieces. The size of the small piece is not particularly limited, but specifically, it is preferable to set the length (long side) to a value in the range of 0.1 to 50 mm using a cutter mixer or the like, The value is more preferably in the range of 0.5 to 30 mm, and even more preferably in the range of 1 to 5 mm.

(2) Step of extracting fucoidan As conditions for determining the extraction efficiency and molecular weight of fucoidan,
The extraction conditions (type of organic acid, amount of organic acid used, extraction temperature, extraction time, extraction pH value, stirring conditions) in the first embodiment will be described.

Kinds of Organic Acids In carrying out the extraction method, citric acid, acetic acid, propionic acid, butyric acid, valeric acid, stearic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, phthalic acid It is preferable to use at least one organic acid selected from the group consisting of glycolic acid and benzoic acid. In addition, citric acid is preferably used because the pH value is easily adjusted and a high extraction efficiency is obtained. Furthermore, even when citric acid and another organic acid are used in combination, the amount of the organic acid used is set to 100%.
Weight percent, the amount of citric acid used was 5%
The value is preferably at least 0% by weight, more preferably at least 70% by weight, even more preferably at least 90% by weight.

Amount of Organic Acid Used In carrying out the extraction method of the present invention, the amount of the organic acid used should be 1 to 10 per 1000 g of Okinawa mozuku.
The value is preferably within a range of 0 g. The reason for this is
When the amount of the organic acid is less than 1 g, the extraction efficiency per unit time may be remarkably reduced. On the other hand, when the amount of the organic acid exceeds 1000 g, the amount of impurities increases, This is because the extraction efficiency may decrease. Therefore, since the balance between the extraction efficiency and the amount of impurities contained becomes better, the amount of the organic acid to be used is reduced by 2 g per 1000 g of Okinawa mozuku.
Preferably, the value is in the range of 50 to 50 g, and 5 to 30 g.
More preferably, the value is within the range of g.

Extraction Temperature In carrying out the extraction method of the present invention, the extraction temperature is preferably set to a value within the range of 25 to 95 ° C. The reason for this is that if the extraction temperature is lower than 25 ° C., the extraction efficiency may be significantly reduced. On the other hand, if the extraction temperature is higher than 95 ° C., production control becomes difficult or fucoidan is excessively decomposed. This is because there are cases where Therefore, it is preferable to set the extraction temperature to a value in the range of 30 to 90 ° C., and to set the value to a value in the range of 50 to 88 ° C. since the balance between the extraction efficiency and the production control becomes better. Is more preferred.

Extraction pH Value In carrying out the extraction method of the present invention, the pH value at the time of extraction must be within a range of 2 to 6. The reason for this is that if the pH value is less than 2, the corrosiveness to the production equipment increases, while if the pH value exceeds 6, the extraction efficiency is significantly reduced. Therefore, since the balance between the corrosiveness to the production equipment and the extraction efficiency becomes better, the pH value at the time of extraction is set to 3.0 to 3.0.
Preferably, the value is in the range of 5.5,
More preferably, the value is in the range of 5.0.

Extraction Time In carrying out the extraction method, the extraction time in the extraction step is preferably set to a value within the range of 0.5 to 72 hours. The reason is that when the extraction time is less than 0.5 hours,
This is because the extraction efficiency may be significantly reduced, while if the extraction time exceeds 72 hours, it may be economically disadvantageous. Therefore, since the balance between economy and extraction efficiency becomes better, it is preferable to set the extraction time to a value within the range of 1 to 24 hours.
More preferably, it is set to a value within the range of 5 to 5 hours.

Stirring Conditions In carrying out the extraction method, in the extraction vessel,
It is preferred to stir. Specifically, it is preferable to stir using a stirring blade at a rotation speed of 5 to 200 rpm, more preferably stirring at a rotation speed of 10 to 100 rpm, and more preferably stirring at a rotation speed of 20 to 80 rpm. preferable. The reason is that the rotation speed of the stirring blade is 5 rpm
When the rotation speed of the stirring blades exceeds 200 rpm, air bubbles are apt to be entrained, and on the other hand, the extraction efficiency is lowered and the production equipment is large. This is because it may be.

(3) Post-treatment step of fucoidan In the first embodiment, in order to finally obtain fucoidan, the extract obtained in the extraction step is subjected to post-treatment (centrifugation, desalting, concentration, powdering). Is preferred.

Centrifugation After the obtained extract is stored in a filter cloth of a centrifuge,
By performing centrifugation, solid-liquid separation can be performed. That is, by performing the centrifugation treatment, it is possible to efficiently separate a solid content such as impurities from a solution containing a large amount of fucoidan. Here, the centrifugation treatment conditions are not particularly limited. For example, after confirming that the extract obtained in the extraction step has reached a temperature of 40 ° C. or less,
3,000-100,000 rpm, 1-3
Preferably, the time is 0 minutes.

Desalting The liquid obtained by centrifugation is preferably subjected to ultrafiltration using an ultrafiltration apparatus, for example, under the condition of a molecular weight cut off of 6,000 or less. By performing the ultrafiltration treatment in this way, excluding low molecular weight components,
A solution containing a large amount of fucoidan component can be obtained as an ultrafiltration concentrate, and as a result, fucoidan having a salt content and a molecular weight within a predetermined range can be efficiently obtained. Until the salt concentration in the filtrate (ultrafiltration concentrated solution) measured by the salt meter becomes 0.1% by weight or less, the ultrafiltration comprising the ultrafiltration concentration and the pressurization of the filtered water is performed. It is preferable to repeat the treatment.

Concentration It is preferable that the concentration of fucoidan in the obtained ultrafiltration concentrate is adjusted to a value of, for example, two times or more by using a reduced pressure concentrator. By concentrating in this manner, pulverization in a subsequent step becomes easy, and fucoidan powder can be obtained in high yield.

Powderization For example, using a spray drying device or a freeze drying device,
Fucoidan powder excluding impurities can be efficiently obtained. When a spray-drying device is used, a fusing agent such as dextrin is added to a fucoidan concentrated solution obtained by a reduced-pressure concentrating device in an amount of 50 to 500 parts by weight per 100 parts by weight of fucoidan so that powdering is easy. It is preferable to add within the range.

[Second Embodiment] The second embodiment is also a method for extracting fucoidan that sequentially includes the above steps (1) to (3), as in the first embodiment. However, (2)
In the fucoidan extraction step, a mixture of an organic acid and an inorganic acid is used as an extractant. Therefore, for such an extractant,
I will explain mainly.

First, as the organic acid used in the second embodiment, those similar to those described in the first embodiment can be used. Therefore, description of the organic acid here is omitted. The inorganic acid used in the second embodiment includes, for example, at least one selected from the group consisting of formic acid, hydrochloric acid, sulfuric acid, and nitric acid. However, in order to effectively prevent corrosion on manufacturing equipment,
Even when an inorganic acid is added, the pH at the time of extraction needs to be a value within the range of 2 to 6. Therefore, when the total amount of the extractant is 100% by weight, the amount of the inorganic acid used is 5%.
It is preferably set to a value of less than 0% by weight, more preferably to a value in the range of 0.1 to 30.0% by weight, and still more preferably to a value of 1.0 to 10.0% by weight. Value within the range.

When an organic acid and an inorganic acid are used as the extractant, the amount of the inorganic acid needs to be relatively small, so that the extraction efficiency may be reduced. Is preferably within a relatively high temperature range of 40 to 95 ° C, more preferably a value within a range of 50 to 95 ° C, and even more preferably a value within a range of 60 to 90 ° C. .

As a modification of the second embodiment, it is preferable to use an organic acid and an inorganic acid separately. However, even in such a case, it is preferable that the amount of the inorganic acid be within the above-mentioned range in order to effectively prevent corrosion of the manufacturing equipment.

[0040]

[Example 1] (Manufacture of fucoidan) 250 kg of salted okinawa mozuku (origin: Nakijin) was washed three times with running water to remove salt on the surface and then in a 1,000 liter container. And immersed in tap water for 1 hour while flowing water.
Next, the Okinawa mozuku was taken out of the container, and the length (long side) of the Okinawa mozuku was set to about 2 mm using a cutter mixer. Fucoidan was extracted from the fragmented Okinawa mozuku under the following extraction conditions, and finally 5 kg of fucoidan powder was produced under the following post-treatment conditions.

Extraction container: made of stainless steel 304 / capacity 500 liter / with a stirrer Extractant: citric acid Extractant usage: 10 g / Okinawa mozuku 1000 g Extraction temperature: 88 ° C. Extraction pH: 3.0 Extraction time: 1 hour Stirring Conditions: Use of propeller / Rotation speed 50 rpm Centrifugation: Rotation speed 100,000 rpm / 60 minutes Ultrafiltration treatment: Molecular weight cut off of 6,000 or less / Processing time 180 minutes Concentration treatment: Concentration of fucoidan concentration about twice : Spray-drying method (Dextrin is used as a shaping agent at a weight ratio of 1: 1) / Average particle diameter (equivalent to 100 mesh)

(Evaluation of fucoidan) (1) Component evaluation The content of fucoidan in the obtained fucoidan powder was measured by an anthrone sulfate method, and found to be 54.0% by weight.
Met. The amount of the sulfated-fucose-containing polysaccharide in the obtained fucoidan was measured by a carbazole method, and was found to be 36.0% by weight. In addition, the amount of sulfuric acid in the obtained fucoidan was measured by ion chromatography and found to be 13.3% by weight. 550 ° C
When the ash content in the obtained fucoidan was measured by the heat ashing method, it was 22% by weight or less, and when the water content in the obtained fucoidan was measured by the 105 ° C. heat drying method, it was 6% by weight or less. Was.

(2) Yield The yield of the obtained fucose was calculated on the basis of the used amount of Okinawa mozuku as a raw material. As a result, a high value of 2.0% was obtained.

(3) Average molecular weight The average molecular weight (average weight molecular weight) of the obtained fucoidan was measured by gel filtration method to be 180,000.
Met. Accordingly, it was confirmed that the average molecular weight was within the range of the preferable average molecular weight of the present invention.

(4) Number of bacteria The number of general bacteria of the obtained fucoidan was measured by a standard agar medium method, and it was confirmed that the number was less than 300 per 1 g of unit weight. Moreover, when the obtained Escherichia coli group of fucoidan was measured by the BGLB method, it was confirmed to be negative.

(5) Anticancer activity 1 μm of the obtained fucoidan was added to human promyelocytic leukemia cells (50,000) cultured on a Petri dish by a standard agar medium method.
g / ml was added and culture was continued in that state.
As a result, the number of cells was reduced to about 30,000 at the culturing time of 18 hours, and further culturing was continued. At the culturing time of 40 hours, the number of cells was reduced to 0 (disappearing). On the other hand, in the control without addition of fucoidan, the number of cells increased to about 60,000 at 18 hours of culturing time, and the number of cells increased to about 150,000 at culturing time of 40 hours after culturing was continued. did. Therefore, it was confirmed that the obtained fucoidan has an excellent anticancer effect on human promyelocytic leukemia cells.

(6) Induction of apoptosis 1 μm of the obtained fucoidan was added to human promyelocytic leukemia cells (50,000) cultured on a Petri dish by a standard agar medium method.
g / ml was added, culture was continued in that state, and apoptosis (percentage of dead cells) was measured. As a result, at the start of culture, apoptosis was about 20%, but at 22 hours of culture, apoptosis increased to about 70%, and at 48 hours of culture, apoptosis was further increased by about 90%.
At 70 hours incubation time, apoptosis further increased to about 100%, and all cells became dead cells. On the other hand, in the control to which fucoidan was not added, at the start of culture, the culture time was 22 hours, 48 hours, and 7 hours.
At 0 hours, each apoptosis was about 20%, with no change in apoptosis. Therefore, it was confirmed that the obtained fucoidan has an excellent apoptosis-inducing effect on human promyelocytic leukemia cells.

(7) Corrosion A small piece (length 10) of stainless steel 304 constituting the extraction container
cm, width 2.54 cm, thickness 0.1 mm) to 100 m
1 of the extractant and kept at a temperature of 90 ° C.
No corrosion was observed after 000 hours and after 2,000 hours.

Example 2 (Production of fucoidan) Fucoidan was produced in the same manner as in Example 1 except that the extraction temperature was increased from 88 ° C. to 95 ° C., and the extraction time was changed from 1 hour to 0.5 hour. .

(Evaluation of fucoidan) As in Example 1,
For the obtained fucoidan, (1) component evaluation, (2)
The yield, (3) average molecular weight, (4) bacterial count, (5) anticancer activity, (6) apoptosis-inducing activity, and (7) corrosiveness were evaluated. Similar results were obtained.

[Example 3] (Production of fucoidan) Citric acid and hydrochloric acid (hydrochloric acid concentration: 0.02N) were mixed and used as an extractant instead of citric acid, and the pH of the extraction step was adjusted to 3.0. Fucoidan was produced in the same manner as in Example 1 except that the fucoidan was 2.0.

(Evaluation of fucoidan) As in Example 1,
For the obtained fucoidan, (1) component evaluation, (2)
The yield, (3) average molecular weight, (4) bacterial count, (5) anticancer activity, (6) apoptosis-inducing activity, and (7) corrosiveness were evaluated. Comparable results were obtained.

[Examples 4 and 5] (Production of fucoidan) As Okinawa mozuku, raw Okinawa mozuku (Example 4) and salted product (Example 5) produced from Chinen were used instead of salted products produced from Nakijin. Otherwise, fucoidan was produced in the same manner as in Example 1.

(Evaluation of fucoidan) As in Example 1,
For the obtained fucoidan, (1) component evaluation, (2)
The yield, (3) average molecular weight, (4) bacterial count, (5) anticancer activity, (6) apoptosis-inducing activity, and (7) corrosiveness were evaluated. The result equivalent to 1 was obtained.

[Comparative Example 1] (Production of fucoidan) Instead of citric acid, 0.2 N hydrochloric acid was used as an extractant, the pH value in the extraction step was adjusted from 3.0 to 2.0, and the extraction temperature was adjusted. Was changed from 88 ° C. to 25 ° C., and the extraction time was changed from 2 hours to 16 hours, thereby producing fucoidan in the same manner as in Example 1.

(Evaluation of fucoidan) As in Example 1,
About the obtained fucoidan, (1) component evaluation, (3)
The average molecular weight and (7) corrosivity were evaluated. As a result, corrosivity due to the extractant was confirmed, and the average molecular weight of the obtained fucoidan was 100,000. In addition, about component evaluation, it was equivalent to Example 1.

[Comparative Example 2] (Production of fucoidan) Fucoidan was produced in the same manner as in Comparative Example 1 except that the extraction temperature in Comparative Example 1 was changed from 25 ° C to 95 ° C.

(Evaluation of fucoidan) As in Example 1,
About the obtained fucoidan, (1) component evaluation, (3)
The average molecular weight and (7) corrosivity were evaluated. As a result, further corrosiveness due to the extractant was confirmed, and the average molecular weight of the obtained fucoidan was 70,000 or less.
In addition, about component evaluation, it was equivalent to Example 1.

[0059]

As described in detail above, according to the method for extracting fucoidan of the present invention, an organic acid is used as an extractant, and the pH value is restricted to a predetermined range. Fucoidan having a desired average molecular weight can be efficiently obtained without problems such as corrosion. Further, according to a preferred embodiment of the method for extracting fucoidan of the present invention, an organic acid and an inorganic acid are used in combination as an extractant, and the pH value is restricted to a predetermined range, so that corrosion and the like in production equipment are prevented. Not only is there no problem, but higher extraction efficiency can be obtained.

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Claims (7)

[Claims] 1. A method for extracting fucoidan from Okinawa mozuku, wherein an organic acid is used as an extractant and the pH of the extraction step is set to a value within the range of 2 to 6. 2. Per 1000 g of the Okinawa mozuku,
The method for extracting fucoidan according to claim 1, wherein the amount of the organic acid used is a value within a range of 1 to 100 g. 3. The organic acid is citric acid, acetic acid, propionic acid, butyric acid, valeric acid, stearic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, phthalic acid, glycolic acid, The method for extracting fucoidan according to claim 1 or 2, wherein the method is at least one compound selected from the group consisting of benzoic acid. 4. The method for extracting fucoidan according to claim 1, wherein the temperature in the extraction step is a value within a range of 25 to 95 ° C. 5. An extraction time of the extraction step is 0.5 to 72.
5. A value within a time range.
The method for extracting fucoidan according to any one of the above. 6. The method according to claim 1, wherein at least one inorganic acid selected from the group consisting of formic acid, hydrochloric acid, sulfuric acid, and nitric acid is used together with the organic acid. How to extract fucoidan. 7. The fucoidan having an average molecular weight of 10,
The method for extracting fucoidan according to any one of claims 1 to 6, wherein the value is within a range of 000 to 1,000,000.