JPH10298175A - Production of water-soluble soybean isoflavone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a water-soluble soybean isoflavone high in water-solubility, capable of manifesting a good stability with the passage of time when dissolving the one by mixing a crude extract of a soybean with cyclodextrin in an aqueous solution, and removing an insoluble material therefrom. SOLUTION: (A) A crude extract obtained from a soybean raw material (preferably soybean hypocotyl, etc., having high content of the isoflavone) is mixed with (B) cyclodextrin in an aqueous solution, and an insoluble material is removed from the obtained mixture to provide the objective water-soluble soybean isoflavone in the method for producing the water-soluble soybean isoflavone. Preferably, the pH of the aqueous solution when mixing the components A with B is regulated so as to be 2-8, and the temperature is regulated so as to be 5-40 deg.C. The aqueous solution preferably includes no organic solvent. A method such as a centrifugation and a filtration can be used for the removal of the impurity. The objective soybean isoflavone useful for prevention, etc., of osteoporosis is cheaply and readily produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a water-soluble soy isoflavone which is effective for preventing osteoporosis and the like.

[0002]

BACKGROUND OF THE INVENTION Isoflavone derivatives are known to be effective for adult diseases such as osteoporosis and hyperlipidemia. Therefore, intake of soybeans rich in isoflavone derivatives is recommended, and various methods for extracting the same have been proposed.

As a method for producing soy isoflavone in large quantities, Japanese Patent Application Laid-Open No. 62-126186 proposes a method in which a soybean extract is brought into contact with a synthetic resin and then the isoflavone is eluted. However, there is a problem that the extract obtained by this method has poor solubility in an aqueous solution and has poor stability in an aqueous solution. This extract precipitates with time at a high concentration, not only in an acidic region in an aqueous solution but also in an alkaline aqueous solution in which the solubility of isoflavones increases.

As a method of stably blending a flavonoid such as isoflavone in an aqueous solution at a high concentration, a method of clathrate with cyclodextrin is known.

For example, JP-A-6-88993 discloses a method of producing an inclusion complex of 7-isopropoxy-isoflavone with cyclodextrin to enhance solubility. JP-A-59-137499 discloses the production of an inclusion compound of rutin with cyclodextrin. However, the use of a purified product of high purity results in a high price, and there is no suggestion about a production method by extraction from soybean.

Japanese Unexamined Patent Publication (Kokai) No. 63-317059 discloses a method for producing boiled soybeans by adding β-cyclodextrin or γ-cyclodextrin during the production of heat-sterilized soybeans and storing the isoflavones. A production method for preventing precipitation of is disclosed. However, its stability in aqueous solutions containing high concentrations of soy isoflavones is unknown.

[0007] Furthermore, isoflavone derivatives are effective for the prevention and treatment of various diseases. For example, it is necessary to take about 50 mg per day to exert their effects on the prevention of osteoporosis. However, daidzin, for example, has a very low solubility in distilled water (25 ° C.) of 0.0033 mg / ml, and in the case of ingesting an effective amount of 50 mg / day as a drink, it is necessary to take a large amount that cannot be taken. , It is necessary to increase the solubility.

[0008] In addition, the intestinal absorption can be enhanced by making it somewhat water-soluble.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a water-soluble soy isoflavone which is dissolved in an aqueous solution at a high concentration and has good aging stability.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors surprisingly mixed a soybean crude extract with cyclodextrin in an aqueous solution to remove insolubles. As a result, it has been found that a water-soluble soy isoflavone having high water solubility and good stability over time during dissolution can be obtained, and the present invention has been completed.

That is, the gist of the present invention is to resuspend a crude soybean extract obtained by solvent extraction or the like in an aqueous solution and mix various cyclodextrins together. Thereafter, insolubles are removed by centrifugation, filtration, or the like. The solution containing the obtained transparent water-soluble soy isoflavone may be used as it is, or further concentrated,
It is a manufacturing method that may be used after solidification, and has a very low manufacturing cost and is easily implemented.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the production method of the present invention, raw soybeans include whole soybeans, dehulled soybeans, defatted hypocotyls, soybean hypocotyls, soybean flour, or broth produced in the step of producing tofu or isolated soybean protein. Whey or the like, preferably soybean hypocotyl or the like having a high isoflavone content is used.

The method for obtaining a soybean crude extract as a raw material used in the production method of the present invention from the above soybean raw material is not particularly limited, but the following steps can be employed. When a solid material such as whole soybean, dehulled soybean, defatted hypocotyl, soybean hypocotyl, and soybean flour is used as a raw material, first, it is shredded and pulverized by a pulverizer, and an extraction solvent is added to obtain a soybean crude extract solution. As the extraction solvent, organic solvents such as water, alcohols such as methanol, ethanol and isopropanol, and ethers such as acetone are used. Preferably, aqueous alcohol is used, especially 70-90% alcohol, preferably about 80% aqueous alcohol. The extraction can be carried out by immersion at room temperature. However, if the extraction is carried out at about 70 ° C. under reflux, the malonyl compound which is an isoflavone glycoside is decomposed, and the solubilization by cyclodextrin is improved. The obtained soybean crude extract solution is concentrated or dried.

When the soybean crude extract solution has a low isoflavone content, it is further concentrated using a synthetic resin. The crude extract containing a high concentration of isoflavones can be obtained, for example, by the method described in JP-A-62-126186 or the method of Kitagawa et al. (Journal of the Japan Society of Food Industry, 33 (12), 821-82).
5: 1986). As synthetic resins, for example, Diaion HP-20 (manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) which is a porous styrene divinylbenzene resin, Amberlite XAD-2, XAD-4 (manufactured by Rohm and Haas), Dulite S-861, Using S-862 (manufactured by Sumitomo Chemical Co., Ltd.), for example, 1/50 to 1
/ 5 times the amount is packed in a column, and the soybean crude extract solution is purified. As the eluate, a 30-80% aqueous alcohol solution is used. However, glycosides are more easily solubilized by cyclodextrins than aglycones. Therefore, it is possible to recover isoflavones mainly composed of glycosides by using a 30 to 50% aqueous alcohol solution. A more stable beverage in the final product is preferred. The concentrate is further heated and reduced in pressure to completely remove the organic solvent.

According to this step, the isoflavone content in the solid content is 20 to 90%, usually 20 to 70%, preferably 30 to 90%.
A 50% soybean crude extract is obtained. Other components consist of soybean saponin and soybean protein.

The present invention is a method for producing a soybean isoflavone extract in which the stability of the soybean crude extract in an aqueous solution is improved by the following operation. That is, the soybean crude extract is
The various cyclodextrins are suspended and mixed in an aqueous solution. Thereafter, insolubles are removed by centrifugation, filtration, or the like, and transparent water-soluble soy isoflavone is obtained.

First, a crude soybean extract is suspended in water. At that time, the concentration of soy isoflavone is 0.1 to 100 mg / m
1, preferably 0.1 to 10 mg / ml. In addition,
The amount of soy isoflavone can be determined as follows. That is, the appropriately diluted sample is quantified by high performance liquid chromatography under the following conditions. Column: Silica gel reverse phase ODS column, mobile phase: acetonitrile: water:
Acetic acid = 15: 84.9: 0.1 to 35: 64.9: 0.1, flow rate: 1.0 ml / min,
Column temperature: 35 ° C., detection method: UV at 260 nm, and the sum of the amounts of daidzin and genistin in the obtained chromatogram was defined as the amount of soy isoflavone.

As the cyclodextrin to be mixed, α, β, γ-cyclodextrin, G2β-cyclodextrin and G1β-cyclodextrin, or a mixture thereof is used. Particularly, β-cyclodextrin, G2β-cyclodextrin, and G1β-cyclodextrin are preferable. The concentration of cyclodextrin in the aqueous solution is in the range of 2 to 200 mg / ml, preferably 10 to 100 mg / ml. If the amount of cyclodextrin is more than that, it is not desirable from an economic point of view, and depending on the type of cyclodextrin, its own solubility becomes a problem.

The ratio between the crude extract of soy isoflavone and cyclodextrin is 1: 0.5 to 1: 1 by weight.
50, preferably 1: 5 to 1:15.

The weight ratio of soy isoflavone to cyclodextrin is preferably from 1: 2 to 1:20. When the ratio is lower than 1: 2, the soybean saponin or soybean protein which causes an interaction between the components in the extract during the storage period is dissolved, and as a result, precipitation occurs, resulting in insufficient stability. When it is higher than 20, the weight of the cyclodextrin becomes unnecessarily large when powdered, which is not desirable in terms of dosage form and economy. The pH of the aqueous solution at the time of mixing is adjusted to 2 to 8, preferably 3 to 6. The acid for adjusting the pH of the aqueous solution may be any of inorganic acids and organic acids that can be used in foods, such as hydrochloric acid, citric acid, malic acid, acetic acid, phosphoric acid, and ascorbic acid. Is exemplified. When the pH exceeds 8, although it is temporarily dissolved at the time of this step, other components such as soybean saponin and soybean protein in soybean are also dissolved in a large amount, and when added to a liquid beverage such as an acidic beverage, A precipitate forms during storage. When the pH is lower than 2, deterioration of the water-soluble soy isoflavone itself is concerned.

The mixing is from 5 ° C. to 40 ° C., preferably 15 ° C.
To 25 ° C. If the temperature exceeds 40 ° C., although it is temporarily dissolved in the present step, after cooling, components causing precipitation may be mixed. Further, this aqueous solution must not contain an organic solvent such as ethanol. This is because when this step is performed with an aqueous solution containing an organic solvent,
This is because soy isoflavones having good solubility are obtained temporarily, but then precipitate over time. Therefore,
It is necessary to remove the organic solvent from the raw soybean crude extract in advance.

By the above-mentioned production process, not only soy isoflavones, which are originally poorly water-soluble but also produced by concentrating the soybean extract, are surprisingly soybean saponin and soybean protein before treatment. / 2 to 1/20, and the stability in an aqueous solution is improved.
Furthermore, a clear aqueous solution of soy isoflavone with a high content can be obtained by subjecting the suspension after mixing the above-mentioned crude extract of soybean and cyclodextrin to a process such as centrifugation and filtration.

The centrifugation is preferably performed at 1000 to 400
Perform at 0 rpm for 20-120 minutes.

Further, the mixed suspension is filtered if necessary. The filtration is performed by a filter of about 0.1 to 5 μm such as cellulose acetate.

The soybean isoflavone aqueous solution, which is a filtrate, contains a high concentration of isoflavone and is contained in an amount of about 0.1 to 4.5 mg
/ Ml, so that the solubility of daidzin, a kind of soy isoflavone, was about 1000 times higher than that of 0.0033 mg / ml.

This filtrate may be directly blended into a beverage, or may be concentrated and dried in consideration of preservation up to the blend. As dry weight, soy isoflavone is 0.1-9
0, preferably 0.5 to 50, particularly preferably 1 to 20
% By weight, and the balance is substantially cyclodextrin.

The water-soluble soy isoflavone thus obtained may be provided as a drink, and in that case, 0.1 to 4.5 mg / ml of soy isoflavone can be blended. Further, it may be provided as a solid such as tablets and granules.

[0028]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of experimental examples and examples, but the present invention is not limited thereto.

Experimental Example 1 Examination of cyclodextrin addition conditions Soybean crude extract 50 mg (20 mg as isoflavone amount)
And 100 mg of β-cyclodextrin were suspended in 5 ml of different solvents, pH and temperature in different tubes. At this time, the pH was adjusted with citric acid or an aqueous sodium hydroxide solution. Thereafter, the mixture was shaken for 10 minutes, centrifuged (2000 rpm, 60 min) and filtered through a 0.45 μm filter, and then the filtrate was vacuum-dried to dryness. The obtained powder was again dissolved in 50 ml of water as soy isoflavone in consideration of application in acidic beverages, adjusted to pH = 3.8 with citric acid, and subjected to a stability test at 40 ° C. for one month. Done. Table 1 shows the results.

[0030]

[Table 1]

Influence of pH When this treatment was carried out at pH 9 or higher in an aqueous solution, the filtrate was temporarily completely dissolved, but precipitated in the stability test under any conditions. However, when this treatment is carried out at a pH of 8 or less, it becomes clear that saponins, soybean proteins, etc., which cause an interaction with the solubilized isoflavone during storage during storage and cause precipitation, can be easily separated. Was. Influence of Solvent When this treatment was performed in an alcohol solution, the dried powder of the filtrate containing soy isoflavone was completely dissolved temporarily. However, it precipitated after one month in the stability test. Influence of temperature When this treatment is performed under heating of about 60 ° C,
As in the case of the treatment in the alcohol solution, the filtrate was temporarily completely dissolved, but precipitated in the stability test under any conditions.

Experimental Example 2 Examination of the amount of cyclodextrin added 50 mg of soybean crude extract (20 mg as isoflavone amount)
And various cyclodextrins 1, 10, 50, 10
0, 150, 200 and 300 mg were added according to the cyclodextrin addition conditions obtained in Experimental Example 1 (pH <9, 2
(0 ° C.) suspended in a test tube containing 5 ml of an aqueous solution, shaken for 10 minutes, centrifuged (2000 rpm, 60 min) and filtered through a 0.45 μm filter, and then the filtrate was dried in vacuo and dried. Hardened. The obtained powder was again dissolved in 50 ml of water as 50 mg of soy isoflavone,
The pH was adjusted to 3.8 with citric acid, and a stability test at 40 ° C. for one month was performed. Table 2 shows the results.

[0033]

[Table 2]

Influence of the structure of soy isoflavone Compared with aglycone, the use of glycosides showed good solubility, especially the glycosides from which the malonyl derivative had been removed had the highest solubility. Influence of the amount of cyclodextrin added When the amount of cyclodextrin added was 100 mg or less, the filtrate was completely dissolved temporarily, but a precipitate was formed in the stability test. However, when the amount of cyclodextrin added was 100 mg or more, the stability was good in any case. Effect of the type of cyclodextrin The solubility of G2β-CD and CD containing G2β-CD, which are branched cyclodextrins, was higher than that of unbranched β-CD.

Example 1 As a soybean raw material, 50 kg of soybean hypocotyl was pulverized, and refluxed and extracted at about 70 ° C. with 250 L of an 80% aqueous alcohol solution, and the soybean crude extract solution was concentrated to about 50 L by vacuum concentration. The solution was adsorbed on Diaion HP-20 (manufactured by Mitsubishi Kasei Kogyo), and the soybean crude extract solution was purified. As eluate, 4
A 0% alcohol solution was used. The organic solvent was completely removed from the concentrate by heating and reduced pressure. By this step, 950 g of a soybean crude extract having a soybean isoflavone content of 42% in the solid content was obtained. This crude soybean extract was used as a starting material for the production method of the present invention. First, the crude soybean extract was suspended in 95 L of water to a concentration of 10 mg / ml as soybean isoflavone. The pH was adjusted to pH 5 by adding malic acid powder little by little. G2β-cyclodextrin was added to a concentration of 50 mg / ml. About 2 hours 20 ℃
And stirred. Then, using a centrifuge, 2500
Centrifugation was performed at rpm for 60 minutes. Further, filtration was performed with a filter of about 1 μm. The obtained transparent solution was concentrated by heating to obtain 600 g of a water-soluble soy isoflavone. The soy isoflavone content of this product was 19% by weight.

Example 2 50 Kg of defatted hypocotyl as a soybean material was pulverized, and refluxed and extracted with 250 L of an 80% aqueous alcohol solution at about 70 ° C., and the soybean crude extract solution was concentrated to about 40 L by vacuum concentration. The solution was adsorbed on Diaion HP-20 (manufactured by Mitsubishi Kasei Kogyo), and the soybean crude extract solution was purified. As eluate, 4
A 0% alcohol solution was used. The organic solvent was completely removed from the concentrate by heating and reduced pressure. By this step, 900 g of a soybean crude extract having a soybean isoflavone content of 35% in the solid content was obtained. This crude soy extract was used as starting material in the next step. First, the soybean crude extract was used as soybean isoflavone so as to have a concentration of 8 mg / ml in 110 L of water.
Was suspended. The pH is adjusted by adding malic acid powder little by little.
5 was prepared. 100m Iso-Elite-P manufactured by Nikken Kagaku
g / ml. The mixture was stirred at 25 ° C. for about 2 hours. Thereafter, centrifugation was performed at 2500 rpm for 60 minutes using a centrifuge. Further, filtration was performed with a filter of about 1 μm. The obtained transparent solution was concentrated by heating to obtain 550 g of a water-soluble soy isoflavone. The soy isoflavone content of this product was 15% by weight.

[0037]

Industrial Applicability According to the present invention, there is provided a method for producing a water-soluble soy isoflavone which is dissolved in an aqueous solution at a high concentration and has good stability over time.

Claims (4)

[Claims] 1. A method for producing a water-soluble soy isoflavone, comprising mixing a crude extract obtained from a soybean material with cyclodextrin in an aqueous solution and removing insolubles. 2. The production method according to claim 1, wherein the pH of the aqueous solution at the time of mixing the crude extract with cyclodextrin is 2 to 8. 3. The temperature of the aqueous solution at the time of mixing the crude extract with cyclodextrin is 5 ° C. to 40 ° C.
The manufacturing method as described. 4. The method according to claim 1, wherein the aqueous solution at the time of mixing the crude extract with cyclodextrin does not contain an organic solvent.