Water-soluble konjac root extract and a method of producing the same

Abstract

The purpose of this invention is to provide a water-soluble konjac extract using a simpler method. By separating and removing fatty acid esters and phytosterols from konjac extract extracted with organic solvents, a water-soluble konjac extract containing less than 500 mg / 100g of fatty acid esters, less than 5,000 mg / 100g of phytosterols, more than 5,000 mg / 100g of glucocerebrosides, and containing sterol glycosides can be provided.

Description

Technical Field

[0001] This invention relates to a water-soluble konjac extract and its manufacturing method. Prior Technology

[0002] Konjac is a traditional Japanese agricultural product, rich in dietary fiber and beneficial components, making it a popular food ingredient. During the production of konjac powder, the raw material for making konjac sheets and konjac noodles, a large amount of konjac jelly is generated as a byproduct. Konjac jelly contains many beneficial components, especially glycosphingolipids, particularly glucocerebroside. Methods for producing glycosphingolipids and other components from konjac jelly are well-known (e.g., Patent Document 1, Patent Document 2, Patent Document 3).

[0003] Glycosphingolipids are digested and absorbed in the body after oral ingestion. They enhance skin hydration and are marketed as functional food products. Furthermore, glycosphingolipids are known to improve skin hydration and alleviate dryness, roughness, atopic dermatitis, and other skin abnormalities when applied directly to the skin. Recently, new functionalities of glycosphingolipids as Alzheimer's disease preventative agents have been discovered (e.g., Patent Document 4). Glycosphingolipids are attracting attention not only in the food industry but also in the pharmaceutical and cosmetic fields.

[0004] Glycosphingolipids are found not only in konjac but also in various other plants such as wheat, rice, corn, peaches, and pineapples. Currently, glycosphingolipids derived from these plants are sold for food and cosmetic purposes. However, plant extracts containing glycosphingolipids are completely insoluble in water as is. Therefore, methods for preparing water-soluble compositions from plant extracts containing glycosphingolipids using emulsifiers such as polyglycerol fatty acid esters are known (e.g., Patent Document 5). When konjac extracts containing glycosphingolipids extracted from konjac are extracted with organic solvents, they also do not completely dissolve or suspend in water as is, but rather precipitate. To make konjac extracts stably soluble in water, emulsifiers such as polyglycerol fatty acid esters, sucrose fatty acid esters, and enzymatically decomposed lecithin have been used to make konjac extracts soluble and suitable for inclusion in various beverages, cosmetics, and pharmaceuticals.

[0005] On the other hand, regarding methods for obtaining extracts containing glycosphingolipids from konjac, methods are known such as introducing a solution obtained by dissolving the crude extract of konjac in methanol into a column chromatography process (e.g., Patent Document 6), introducing a solution obtained by dissolving the crude extract of konjac in petroleum ether into a column chromatography process (e.g., Patent Documents 7-11), and solvent extraction of the crude extract of konjac using alkaline methanol and chloroform (e.g., Patent Document 12). [Previous Patent Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent No. 3992425 [Patent Document 2] Japanese Patent No. 3650587 [Patent Document 3] Japanese Patent No. 4753476 [Patent Document 4] Japanese Re-registration No. 2019-078005 [Patent Document 5] Japanese Patent No. 3395444 [Patent Document 6] Japanese Patent Application Publication No. 2003-221592 [Patent Document 7] Chinese Patent Application Publication No. 102190689 Specification [Patent Document 8] Chinese Patent Application Publication No. 102675139 Specification [Patent Document 9] Chinese Patent Application Publication No. 108623492 Specification [Patent Document 10] Chinese Patent Application Publication No. 102351730 Specification [Patent Document 11] Chinese Patent Application Publication No. 108947864 Specification [Patent Document 12] Japanese Patent Application Publication No. 2011-95550 Summary of the Invention

[0007] [The problem that the invention aims to solve]

[0008] As described above, in the method of Patent Document 5, an emulsifier is used to make the konjac extract soluble. However, depending on the emulsifier used and the combination of the emulsifier with other ingredients, the emulsification stability of the resulting aqueous composition deteriorates. Therefore, a method is desired that can ensure the water solubility of the aqueous composition containing konjac extract without adding an emulsifier.

[0009] On the other hand, the water solubility of konjac extract obtained by the methods described in Patent Documents 6-12 is not yet clear. Furthermore, the methods described in Patent Documents 7-12 use petroleum ether (mainly pentane) and chloroform, which are not recognized as extraction solvents in the Japanese Food Additives Manufacturing Standards.

[0010] The purpose of this invention is to provide a konjac extract containing many useful components similar to glycosphingolipids, which can be used as a raw material for cosmetics, health foods and pharmaceuticals in aqueous components of food, cosmetics and pharmaceuticals, and a method for manufacturing the same. [Methods for solving problems]

[0011] The inventors of this case confirmed that konjac extract obtained by extracting konjac powder with ethanol is poorly water-soluble. Furthermore, they considered whether selectively removing components other than beneficial components such as glycosphingolipids could make the konjac extract water-soluble. Therefore, the inventors of this case investigated a method that retains the beneficial components contained in the konjac extract while removing components that hinder water solubility.

[0012] As a result, it was discovered that by reducing the content of phytosterols and neutral lipids such as fatty acid esters in konjac extract, the poor water solubility of konjac extract is improved, making it more easily soluble in water. This invention was accomplished based on the insights and successful examples obtained by the inventors in this case.

[0013] That is, the various aspects of one side of the present invention are as follows. (1) A water-soluble konjac extract, wherein the content of fatty acid esters is less than 1,000 mg / 100g. (2) The water-soluble konjac extract as described in (1) contains phytosterols of less than 5,000 mg / 100g. (3) The water-soluble konjac extract as described in (1) or (2), wherein the content of glucocerebroside is 5,000 mg / 100g or more. (4) The water-soluble konjac extract described in any of (1) to (3) contains sterol glycosides of 500 mg / 100 g or more. (5) A food, cosmetic or pharmaceutical product containing a water-soluble konjac extract as described in any one of (1) to (4). (6) A method for manufacturing a water-soluble konjac extract, comprising: an extraction step of extracting konjac extract from konjac powder using an organic solvent, and a separation step of separating fatty acid esters and phytosterols from the aforementioned konjac extract using column chromatography, thereby reducing the content of fatty acid esters to less than 1,000 mg / 100g and the content of phytosterols to less than 5,000 mg / 100g. (7) A method for manufacturing a water-soluble konjac extract, comprising: an extraction step of extracting konjac extract from konjac powder using an organic solvent, and a removal step of removing fatty acid esters and phytosterols from the konjac extract using an organic solvent different from the organic solvent used in the aforementioned extraction step, thereby reducing the content of fatty acid esters to less than 1,000 mg / 100g and the content of phytosterols to less than 5,000 mg / 100g.

[0014] Another aspect of the present invention is as follows. [1] A water-soluble konjac extract, wherein the content of fatty acid esters is less than 500 mg / 100g, the content of phytosterols is less than 5,000 mg / 100g, the content of glucocerebrosides is more than 5,000 mg / 100g, and it contains sterol glycosides. [2] As described in [1], the water-soluble konjac extract contains 500 mg / 100 g or more of the aforementioned sterol glycosides. [3] A food, cosmetic or pharmaceutical product containing a water-soluble konjac extract as described in [1]. [4] A method for manufacturing a water-soluble konjac extract, comprising: The extraction step of extracting konjac extract from konjac flour using the first organic solvent, and... The fatty acid esters and phytosterols were removed from the aforementioned konjac extract using a second organic solvent, thereby obtaining a water-soluble konjac extract removal step; The aforementioned water-soluble konjac extract contains less than 500 mg / 100g of fatty acid esters, less than 5,000 mg / 100g of phytosterols, more than 5,000 mg / 100g of glucocorticoids, and also contains sterol glycosides; and The aforementioned first organic solvent and the aforementioned second organic solvent are different organic solvents from each other, and are different organic solvents from petroleum ether and chloroform. [5] As described in [4], wherein the first organic solvent mentioned above is ethanol. [6] As described in [4], the second organic solvent mentioned above is acetone. [Effects of the Invention]

[0015] The effects of this invention are as follows. According to the invention of (1), konjac extract can be made water-soluble by making the content of fatty acid esters less than 1,000 mg / 100g. According to the invention of (2), konjac extract can be made water-soluble by making the content of phytosterols below 5,000 mg / 100g. According to the invention of (3), a water-soluble konjac extract containing useful components can be obtained by making the content of glucocerebroside 5,000 mg / 100g or more. According to the invention of (4), a water-soluble konjac extract containing useful components can be obtained by making the sterol glycoside content 500 mg / 100 g or more. According to the invention of (5), it can be used in food, cosmetics and pharmaceuticals without the use of emulsifiers. According to the invention of (6), by using column chromatography to reduce the content of fatty acid esters in konjac extract to less than 1,000 mg / 100g and the content of phytosterols to less than 5,000 mg / 100g, a simple method for manufacturing water-soluble konjac extract with water solubility can be provided. According to the invention of (7), by using an organic solvent removal step that is different from the extraction step, the content of fatty acid esters in konjac extract is reduced to less than 1,000 mg / 100g and the content of phytosterols is reduced to less than 5,000 mg / 100g, thereby providing a simple method for manufacturing water-soluble konjac extract with water solubility.

[0016] The present invention provides a water-soluble konjac extract containing many useful components similar to glycosphingolipids, which can be used as a cosmetic ingredient, health food ingredient, and pharmaceutical ingredient, thereby enabling the manufacture of food, cosmetic, and pharmaceutical products containing a liquid composition of glucocerebroside derived from konjac. Simple Explanation of the Diagram

[0017] [Figure 1] Figure 1 is a flowchart showing the method for manufacturing water-soluble konjac extract. [Figure 2] Figure 2 is a graph showing the results of the evaluation of the water solubility of the general samples (a) to (c) described in the following examples. Implementation

[0018] This invention relates to a konjac extract, which is an extract obtained by organic solvent extraction and exhibits improved water solubility. The following describes in detail an embodiment of the konjac extract of this invention. However, the following embodiment is merely an example used to illustrate the invention, and the invention is not limited to this embodiment.

[0019] 1. Raw materials for water-soluble konjac extract, etc. The konjac used in this embodiment can be raw konjac or processed through drying, grinding, pulverizing, heating, etc. Furthermore, konjac can be processed into fine konjac powder, micro-konjac powder, medium-sized konjac powder, coarse konjac powder, or konjac granules, and can also be processed konjac for commercial consumption. Considering that fine konjac powder, micro-konjac powder, and medium-sized konjac powder are produced in large quantities as byproducts during manufacturing and are subsequently discarded, and that these can be obtained cheaply, konjac granules are a preferred example among these.

[0020] Regarding the organic solvent used for extraction in this embodiment (the first organic solvent), any solvent capable of dissolving glucocerebrosides and sterol glycosides, and not reacting further with the useful components in konjac during extraction, thus not affecting the solution of the problem of this invention, can be used. Furthermore, one organic solvent can be used alone, or two or more organic solvents can be mixed. Examples of the first organic solvent include: monovalent primary alcohols such as methanol, ethanol, and isopropanol; other alcohols such as 2-butanol, ethylene glycol, and propylene glycol; oxygen-containing polar organic solvents such as acetone, dimethyl sulfoxide, dimethyl ether, tetrahydrofuran, and diethyl ether; nitrogen-containing polar organic solvents such as dimethylformamide and pyridine; halogen-containing polar organic solvents such as dichloromethane, chloroform, and trichloroethylene; and non-polar or low-polar organic solvents such as hexane and isooctane. Water may be mixed with the organic solvent depending on the situation. Furthermore, high-pressure liquefied or supercritical fluids such as carbon dioxide, ethane, and trifluoromethane can also be used as organic solvents. Among these, when using konjac extract as a food or food additive, ethanol is preferred, but acetone, hexane, water, and supercritical carbon dioxide can also be used as needed. In this case, the ethanol content in the first organic solvent used for extraction is preferably 70% or more, more preferably 80% or more, further preferably 90% or more, and even more preferably 100%. For example, konjac extract obtained using ethanol as the first organic solvent can be called konjac ethanol extract.

[0021] 2. Preparation of water-soluble konjac extract In manufacturing the water-soluble konjac extract of this embodiment, an extraction step is performed by adding an organic solvent to the konjac to extract the useful components from it. The amount of organic solvent used in the extraction is approximately 1 to 30 times the amount of the raw konjac, preferably 1 to 20 times, and more preferably 1 to 10 times.

[0022] The extraction temperature varies depending on the boiling point of the organic solvent used, but is preferably 0°C to 80°C, and more preferably around room temperature to 60°C. The extraction time is preferably 1 hour to 48 hours, and more preferably 2 hours to 20 hours.

[0023] The extraction method can be a single batch operation in which konjac taro and the aforementioned organic solvent are mixed in a stirred tank, but it is not limited to this. Alternatively, fresh solvent can be added to the residue after extraction to perform the extraction operation again, or the organic solvent can be contacted with the extraction feedstock multiple times. That is, regarding the extraction operation, any method can be used, including batch operation, semi-continuous operation, and countercurrent multi-stage contact operation. Furthermore, well-known extraction methods such as Soxhlet extraction can also be used.

[0024] Next, the extraction residue is separated and removed from the extract obtained from the above extraction step. The separation method is not particularly limited, and well-known methods such as suction filters, filter presses, cylinder filter presses, decanters, centrifuges, and filter centrifuges can be used.

[0025] The resulting extract is then sent to a concentration step. The concentration method is not particularly limited; for example, it can be performed using a vacuum concentration apparatus such as an evaporator, a centrifugal thin-film vacuum evaporator, or by solvent removal through heating. Furthermore, when a supercritical fluid is used as the organic solvent for extraction, solvent removal can be performed simply by depressurization after extraction, thus omitting the concentration step.

[0026] In this embodiment, to facilitate the dissolution of konjac extract in water, the various phytosterols are reduced to below 5,000 mg / 100g, preferably below 4,000 mg / 100g, and more preferably below 3,500 mg / 100g; and / or the various fatty acid esters are reduced to below 1,000 mg / 100g, preferably below 500 mg / 100g, and more preferably below 50 mg / 100g. Phytosterols are sterols represented by sitosterol, campesterol, brassicasterol, stigmasterol, and sitostanol, including phytosterols bonded with fatty acids. Furthermore, fatty acid esters are formed by ester bonds between functional groups such as methyl, ethyl, and propyl and the carboxyl groups of C16-C20 saturated and / or unsaturated fatty acids. Phytosterols and fatty acid esters are quantified using the methods described in the examples below.

[0027] On the other hand, in order to enable the water-soluble konjac extract containing useful components to be used in food, cosmetics, and pharmaceuticals, it is preferable that the water-soluble konjac extract contains glucocerebroside and sterol glycosides, which are useful components. Furthermore, the content of glucocerebroside, relative to the total amount of water-soluble konjac extract (100g), is preferably 5,000mg / 100g or more, more preferably 5,000mg / 100g to 50,000mg / 100g, further preferably 10,000mg / 100g to 40,000mg / 100g, and even more preferably 15,000mg / 100g to 30,000mg / 100g or 20,000mg / 100g to 30,000mg / 100g. The content of 1 / 100g and / or sterol glycosides, relative to the total amount of water-soluble konjac extract (100g), is preferably 500mg / 100g or more, more preferably 500mg / 100g to 5,000mg / 100g, further preferably 1,000mg / 100g to 4,000mg / 100g, and even more preferably 1,500mg / 100g to 3,500mg / 100g or 2,000mg / 100g to 3,500mg / 100g.

[0028] Glucocerebrosides and sterol glycosides are poorly soluble in water, or more accurately, lipophilic. However, konjac contains phospholipids such as phosphatidylcholine, which act as emulsifiers, allowing some of the glucocerebrosides and sterol glycosides to dissolve in water. However, konjac extracts also contain a certain concentration or higher of fatty acid esters and phytosterols in addition to glucocerebrosides and sterol glycosides. It is believed that these inhibit the role of phospholipids as emulsifiers, hindering the dissolution of glucocerebrosides and sterol glycosides in konjac extracts in water. The present invention provides a water-soluble konjac extract that, compared to konjac extracts, increases the content of glucocerebrosides and sterol glycosides while reducing the content of fatty acid esters and phytosterols, thereby becoming a water-soluble konjac extract.

[0029] When considering its use as a food product, the method for manufacturing water-soluble konjac extract preferably uses organic solvents (acetone, ethanol, glycerol, ethyl acetate, methyl acetate, diethyl ether, cyclohexane, dichloromethane, 1,1,2-trichloroethylene, edible oils, 1,1,1,2-tetrafluoroethane, 1-butanol, 2-butanol, 2-butanone, 1-propanol, 2-propanol, propylene glycol, hexane, methanol, etc.) listed in the food additive manufacturing standards as the first and second organic solvents. Therefore, it is preferable not to use petroleum ethers such as pentane and chloroform. The water-soluble konjac extract is preferably substantially free of petroleum ethers and chloroform.

[0030] The method for producing a water-soluble konjac extract of the present invention is a method that reduces phytosterols and fatty acid esters. The method for producing a water-soluble konjac extract of the present invention involves using a resin and an organic solvent different from that used in the extraction step.

[0031] The method using resins involves a column chromatography step to separate phytosterols and fatty acid esters from konjac extract. The separation step is not particularly limited as long as it separates the useful components, glucocerebrosides and sterol glycosides, from the phytosterols and fatty acid esters. Examples of separation steps include those using silica gel, ion exchange resins, affinity resins, gel filtration, hydrophobic chromatography resins, and synthetic adsorbents.

[0032] A method using an organic solvent different from that used in the extraction step involves removing phytosterols and fatty acid esters from konjac extract using a second organic solvent (a different organic solvent than that used in the extraction step). Preferably, the removal step uses a second organic solvent that is difficult to dissolve as useful components such as glucocerebrosides and sterol glycosides, but readily dissolves phytosterols and fatty acid esters. Examples of such a second organic solvent include, for example, acetone, hexane, supercritical carbon dioxide, and mixtures thereof, with acetone being the most preferred. The acetone content in the second organic solvent is preferably 70% or more, more preferably 80% or more, further preferably 90% or more, and even more preferably 100%.

[0033] By using organic solvents different from those used in the extraction step, or organic solvents with different compositions than those used in the extraction step, phytosterols and fatty acid esters can be removed efficiently.

[0034] Following the extraction step, for the konjac extract from which the organic solvent used in the extraction step has been removed, a removal step is performed by adding a different organic solvent than that used in the extraction step to remove phytosterols and fatty acid esters. This removal step can be conducted in the same manner as the extraction step. Specifically, the amount of organic solvent used for removing phytosterols and fatty acid esters is preferably 1 to 30 times the amount of the konjac extract, more preferably 5 to 20 times, and even more preferably 5 to 10 times, and the dissolution of the organic solvent can be promoted by stirring or similar means. To simplify operation and increase the yield of water-soluble konjac extract, it is preferable to perform the extraction and removal steps continuously. That is, in a preferred embodiment of the method of the present invention, the konjac extract obtained from the extraction step is not used for other processing, but rather for the removal step.

[0035] The processing temperature varies depending on the boiling point of the solvent used, but it is preferably 0℃~80℃, and even better is around room temperature~60℃.

[0036] Processing time, for example, is 1 hour to 48 hours, preferably 2 hours to 20 hours.

[0037] The removal process can be a single batch operation, but is not limited to this. Fresh organic solvent can be added again to the residue after the first treatment to repeat the process, or the organic solvent can be brought into contact with the konjac extract multiple times. That is, in terms of operation method, any of the following can be used: batch operation, semi-continuous operation, or countercurrent multi-stage contact operation. Furthermore, well-known treatment methods such as Soxhlet extraction can also be used.

[0038] The waste (residue) generated by the use of organic solvents is separated and removed. The separation method is not particularly limited, and well-known methods such as suction filters, filter presses, cylinder filter presses, decanters, centrifuges, and filter centrifuges can be used.

[0039] The resulting water-soluble konjac extract can be used as is, depending on the need, by removing the organic solvents used in column chromatography or other methods. The water-soluble konjac extract can be dissolved using the organic solvents used in the extraction process. Afterwards, by removing the organic solvents, a solid water-soluble konjac extract can be obtained.

[0040] The water-soluble konjac extract of the present invention, obtained by the method described above, contains 5,000 mg / 100g or less of various phytosterols and / or 1,000 mg / 100g or less of various fatty acid esters. When these contents exceed 5,000 mg / 100g and / or 1,000 mg / 100g respectively, the konjac extract will not completely dissolve in water, and undissolved matter will exist, which will become precipitate over time and become difficult to dissolve stably in water. Alternatively, the konjac extract that is temporarily dissolved in water will precipitate over time, and a portion of the water-insoluble konjac extract will precipitate out. By reducing the phytosterols in konjac extract to less than 5,000 mg / 100g and / or reducing the fatty acid esters to less than 1,000 mg / 100g, water-soluble konjac extract can be used as a raw material for cosmetics, food, and pharmaceuticals in a water-soluble form.

[0041] This invention relates to a water-soluble konjac extract, which contains a large amount of sphingolipids and sterol glycosides that play important roles in skin moisturizing and dementia prevention. By adding it to food and cosmetics, it can bring about excellent effects. Examples of food products include: health foods and beverages, staple foods such as bread, udon noodles, buckwheat noodles, and rice; snacks such as biscuits, cakes, jellies, puddings, candies, chewing gum, and yogurt; soft drinks; alcoholic beverages; coffee, tea, and milk. Examples of cosmetic products include: lotions, emulsions, moisturizers, perfumes, lip balms, and lipsticks applied to the skin; hair growth products, hair-promoting agents, hair oils, styling products, hair sprays, hair dyes, hair conditioners, and eyelash products applied to the hair; facial cleansers, facial soaps, shampoos, hair conditioners, and hair washes used for washing the face and hair; and bath products. [Example]

[0042] The following embodiments are shown to illustrate the invention in more detail. However, each embodiment and its combination is an example only. Appropriate additions, omissions, substitutions, and other modifications of the components are possible without departing from the spirit of the invention. The invention is not limited to the embodiments, but only to the scope of the claims.

[0043] The measuring device and measuring method used in the following embodiments will be described.

[0044] (1) Quantitative methods for phytosterols and fatty acid esters Quantitative analysis of phytosterols and fatty acid esters was performed using gas chromatography (GC). An Agilent Technologies HP 6890 series GC system was used. Detection of each component was performed using a flame ionization detector (FID). Phytosterol separation was achieved using an Agilent Technologies HP-5MS column (30 m long, 0.25 mm diameter, 0.25 μm film thickness). The detector temperature was set to 300 °C, the flow rate to 1.0 mL / min (carrier gas: helium), the syringe temperature to 150 °C, the injection volume to 1 μL, and the split ratio to 50:1. The column oven temperature was initially set at 250 °C, increased to 300 °C at a rate of 10 °C / min, and held for 10 minutes. Fatty acid ester separation was achieved using an Agilent Technologies DB-WAX column (60 m long, 0.25 mm diameter, 0.25 μm film thickness). The detector temperature was set to 280℃, the flow rate to 1.0 mL, and the split ratio to 50:1. The column oven temperature was set to an initial temperature of 50℃, held for 1 minute, then increased to 200℃ at a rate of 25℃ / min, and then increased to 230℃ at a rate of 3℃ / min, held for 13 minutes.

[0045] As standard reagents, β-sitosterol (manufactured by TAMA Biochemical), campesterol (manufactured by TAMA Biochemical), stigmasterol (manufactured by Sigma), ethyl linoleate (manufactured by Sigma), ethyl palmitate (manufactured by Fujifilm and Koichi Chemical), and a qualitative fatty acid methyl ester mixture (FAME Mix, C4-C24) (manufactured by Sigma) were used. A qualitative fatty acid ethyl ester mixture was prepared from the qualitative fatty acid methyl ester mixture by transesterification. These standard reagents were used to measure phytosterols and fatty acid esters.

[0046] (2) Quantitative methods for glucocerebroside and sterol glycosides Quantitative analysis of glucocerebrosides and sterol glycosides was performed using high-performance liquid chromatography (HPLC). A Shimadzu LC-20A HPLC system was used, with a Shimadzu ELSD-LTIII evaporative light scattering detector. An Inertsil SIL100A column was used. The solvent was chloroform:methanol = 9:1 (volume ratio), and measurements were performed at a flow rate of 1.0 mL / min at 37°C. As standards, glucocerebrosides derived from konjac (manufactured by Nagara Science) and β-sitosterol-3-o-glucoside (manufactured by Fujifilm and Hikari Pure Chemicals) were used for the measurements.

[0047] [Reference Example 1] 1 kg of konjac powder was fed into a stirred tank, and 2 L of ethanol was added. The mixture was stirred at room temperature for 2 hours. The resulting mixture was then separated into extract and residue by filtration. The extract was concentrated using an evaporator to obtain 10.7 g of a brownish-red, waxy concentrate (konjac extract). The extract was analyzed for phytosterols, fatty acid esters, glucocerebrosides, and sterol glycosides using the methods described above. The results are shown in Table 1. Furthermore, 1 g of konjac extract was stirred for 10 minutes in a beaker containing 1 L of 70°C warm water and then allowed to return to room temperature. The konjac extract precipitated as a waxy precipitate at the bottom of the beaker, entirely in an unstable, water-insoluble state. Additionally, using methanol instead of ethanol also yielded a brownish-red, waxy concentrate of konjac extract. However, the konjac extract obtained in this way is not stably soluble in water.

[0048] [Example 1] The konjac extract obtained in Reference Example 1 (10.0 g) was dissolved in 100 mL of chloroform, and the resulting solution was passed through a 300 mL glass column filled with silicone. The silicone column was then washed with chloroform at three times its capacity, followed by washing with chloroform / methanol (9 / 1) at one times its capacity. Next, the adsorbed konjac extract was precipitated from the silicone column by passing chloroform / methanol (8 / 2) at twice its capacity. The chloroform / methanol solvent was removed from the precipitated solution using an evaporator, yielding 3.2 g of light brown, blocky solid (water-soluble konjac extract). This water-soluble konjac extract was analyzed in the same manner as in Reference Example 1. The results are shown in Table 1. Furthermore, 1g of this water-soluble konjac extract was stirred for 10 minutes in a beaker containing 1L of 70°C warm water and then allowed to return to room temperature. The result was that the water-soluble konjac extract was completely dissolved in water, with no precipitation observed. Moreover, the resulting aqueous solution was sealed and placed in a 40°C thermostat for one week; no precipitation occurred, and it remained completely dissolved in water.

[0049] [Example 2] The mixture obtained by adding 10.0 g of the konjac extract obtained in Reference Example 1 to 100 mL (10 times the amount) of acetone was stirred at room temperature for 2 hours, and then filtered to separate the acetone solution and residue. The residue was dissolved by adding 100 mL of ethanol, and then immediately filtered to obtain an ethanol solution. The ethanol was removed from this ethanol solution using an evaporator, yielding 4.6 g of light brown, blocky solid (water-soluble konjac extract). This water-soluble konjac extract was analyzed in the same way as in Reference Example 1. The results are shown in Table 1. Furthermore, 1 g of this water-soluble konjac extract was stirred for 10 minutes in a beaker containing 1 L of warm water at 70°C, and then allowed to return to room temperature. The result showed that the water-soluble konjac extract was completely dissolved in water, and no precipitation was observed. Furthermore, the resulting aqueous solution was sealed and placed in a thermostat at 40°C for one week. No precipitation occurred, and it remained completely dissolved in water.

[0050] [Table 1]

[0051] [Example 3] Similar to the method described in Reference Example 1, 10.0 g of konjac extract obtained from konjac powder was mixed with 100 mL (10 times the amount) of acetone. After stirring at room temperature for 2 hours, the mixture was separated into an acetone solution and a residue by filtration. The residue was then dissolved by stirring with 100 mL of ethanol to obtain an ethanol solution.

[0052] Since the fatty acid esters that hinder the solubility of konjac extract in water have been extracted in acetone solution, konjac extract with a fatty acid ester content of 320 mg / 100g (sample (b)) and konjac extract with a fatty acid ester content of 750 mg / 100g (sample (c)) were prepared by mixing a certain amount of the acetone solution with the ethanol solution. After removing the solvent from the obtained konjac extract by vacuum distillation, the solubility of the resulting light brown lumpy solid in water was evaluated. The water-soluble konjac extract of Example 2 (fatty acid ester content of 29 mg / 100g; sample (a)) was also evaluated.

[0053] The sample was added to warm water at 70°C at a concentration of 1 g / L and stirred. The resulting mixture was then allowed to return to room temperature. A photograph of the solution is shown in Figure 2. As shown in Figure 2, compared to samples (a) and (b), which dissolved in water with almost no visible precipitate, sample (c) was almost insoluble in water and produced a coagulated precipitate.

[0054] Thus, it was determined that konjac extract with a fatty acid ester content of less than 750 mg / 100g was a water-soluble konjac extract.

[0055] [Example 4] Except that the amount of acetone was increased to 5 times (50 mL) and 20 times (200 mL), the procedure was carried out in the same manner as in Example 2 to attempt to obtain a water-soluble konjac extract. As a result, when the amount of acetone was increased to 5 times and 20 times, the water-soluble konjac extract could also be obtained by carrying out the procedure in the same manner as in Example 2. [Cross-reference to related applications]

[0056] This application claims priority to Japanese Patent Application No. 2021-215581, filed on December 24, 2021, the entire contents of which are incorporated herein by way of disclosure.

[0057] Furthermore, all records in all documents referenced in the detailed description of the invention in this case, including Patent Documents 1 to 12, are incorporated herein by way of disclosure.

[0058] none

Claims

1. A water-soluble konjac extract, wherein the content of fatty acid esters is less than 500 mg / 100g, the content of phytosterols is less than 5,000 mg / 100g, the content of glucocerebrosides is more than 5,000 mg / 100g, and it contains sterol glycosides.

2. The water-soluble konjac extract as requested in item 1, wherein the content of the sterol glycoside is 500 mg / 100g or more.

3. A food, cosmetic or pharmaceutical product containing a water-soluble konjac extract as claimed in claim 1.

4. A method for producing a water-soluble konjac extract, comprising: an extraction step, extracting konjac extract from konjac powder using a first organic solvent, and a removal step, removing fatty acid esters and phytosterols from the konjac extract using a second organic solvent, thereby obtaining a water-soluble konjac extract; wherein the water-soluble konjac extract contains less than 500 mg / 100g of fatty acid esters, less than 5,000 mg / 100g of phytosterols, more than 5,000 mg / 100g of glucocorticoids, and contains sterol glycosides; and wherein the first organic solvent and the second organic solvent are different organic solvents from each other, and are different from petroleum ether and chloroform.

5. The method for producing water-soluble konjac extract as claimed in claim 4, wherein the first organic solvent is ethanol.

6. The method for producing water-soluble konjac extract as claimed in claim 4, wherein the second organic solvent is acetone.

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