Alkylresorcinol-containing liposoluble composition and method for producing the same

Abstract

To provide a method for producing an alkylresorcinol-containing liposoluble composition that comprises alkylresorcinol as a liposoluble constituent derived from bran of gramineous cereals, the concentration of alkylresorcinol being more than 5 mass%, and the composition having high purity; and to provide the alkylresorcinol-containing liposoluble composition.SOLUTION: There is provided a method for producing an alkylresorcinol-containing liposoluble composition, the method comprising: adding an alkali to a solution obtained by eluting liposoluble components from bran of gramineous cereals to adjust the pH to 10 or more; adding and mixing n-hexane to the resulting solution; separating by a liquid-liquid separation operation an n-hexane phase containing unnecessary liposoluble components other than alkylresorcinol to obtain an ethanol-containing solvent phase; adding an acid to this solvent phase to adjust the pH to 2 to 6, and adding and mixing n-hexane into the resulting ethanol-containing solvent phase; separating the n-hexane phase by a liquid-liquid separation operation; and volatilizing the n-hexane to obtain the alkylresorcinol-containing liposoluble composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an alkylresorcinol-containing fat-soluble composition and a method for producing the same. [Background technology]

[0002] In recent years, with the rise in health awareness, effective utilization of grains such as wheat and rye, which are rich in nutrients such as dietary fiber, vitamins, and minerals, has been investigated. Grains contain alkylresorcinols. Alkylresorcinols are compounds extracted or synthesized from the seed coats of grass grains and nuts, and are known to have anti-obesity, antioxidant, anti-immune, and other effects. Patent Document 1 describes that alkylresorcinols are localized in a region close to the aleurone layer of wheat husk.

[0003] Patent Document 2 describes the extraction of alkylresorcinols from wheat bran by shaking or stirring a mixture of wheat bran and raw oil and fat, followed by centrifugation to recover alkylresorcinols. However, the amount of alkylresorcinols extracted by this centrifugation method was small. Cited Document 3 describes the extraction of alkylresorcinols from barley or its fermentation products using a fat-soluble solvent. However, specific conditions for efficiently extracting alkylresorcinols have not been fully investigated. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 065869 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-136909 [Patent Document 3] Japanese Patent Publication No. 2020-28227 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, alkylresorcinols have been extracted from the bran of grass grains using an organic solvent, and the resulting extract is then evaporated to give an alkylresorcinol-containing composition. The alkylresorcinol concentration in the composition is 4 to 5% by mass, with the remainder consisting of impurities extracted from the bran.

[0006] In recent years, there has been a demand for a highly pure alkylresorcinol-containing fat-soluble composition that contains alkylresorcinol as a fat-soluble component derived from the bran of a grass family grain and has an alkylresorcinol concentration of more than 5% by mass, but such an alkylresorcinol-containing fat-soluble composition has not been provided.The problem that the present invention aims to solve is to provide a method for producing a highly pure alkylresorcinol-containing fat-soluble composition that contains alkylresorcinol as a fat-soluble component derived from the bran of a grass family grain and has an alkylresorcinol concentration of more than 5% by mass, and the fat-soluble composition. [Means for solving the problem]

[0007] The present inventors have conducted extensive research in light of the above-mentioned problems and have found that an alkylresorcinol-containing fat-soluble composition having a high purity of alkylresorcinol can be obtained by extracting alkylresorcinol from the bran of a grass cereal using an ethanol-containing solvent, adding an alkali to the extract, and then adding an acid to neutralize the extract, and then using n-hexane to volatilize the n-hexane from the resulting extract.The present invention was completed based on these findings.

[0008] The present invention provides a fat-soluble component extraction process in which an ethanol-containing solvent is mixed with bran of a grass family grain to elute fat-soluble components in the bran and recover a solution containing the fat-soluble components; an alkali treatment process in which an alkali is added to the solution obtained in the fat-soluble component extraction process to adjust the pH to 10 or higher; a fat-soluble unnecessary component removal process in which n-hexane is added to and mixed with the solution obtained in the alkali treatment process, and a separation operation is performed to separate an n-hexane phase containing fat-soluble unnecessary components other than alkylresorcinols from the ethanol-containing solvent phase; and The present invention relates to a method for producing an alkylresorcinol-containing fat-soluble composition, which includes a neutralization step of adding an acid to the ethanol-containing solvent phase obtained in the soluble unnecessary component removal step to adjust the pH to 2 to 6, an alkylresorcinol recovery step of adding and mixing n-hexane to the ethanol-containing solvent phase obtained in the neutralization step and separating the ethanol-containing solvent phase from an n-hexane phase containing alkylresorcinol by a liquid separation operation, and a concentration step of volatilizing n-hexane from the n-hexane phase obtained in the alkylresorcinol recovery step.

[0009] Preferably, the concentration step provides an alkylresorcinol-containing fat-soluble composition having an alkylresorcinol content of 5.5% by mass or more.

[0010] The acid preferably includes at least one selected from the group consisting of hydrochloric acid, sulfuric acid, and nitric acid.

[0011] Preferably, the bran of the cereal grain of the Gramineae family is obtained by stepwise peeling of the cereal grain of the Gramineae family and collecting the fraction between the outer pericarp of the aleurone layer and the husk.

[0012] The bran of a cereal grain of the Gramineae family preferably includes at least one selected from the group consisting of rye bran and wheat bran.

[0013] The present invention further relates to an alkylresorcinol-containing fat-soluble composition containing alkylresorcinol as a fat-soluble component derived from the bran of a grass family grain and other fat-soluble components, wherein the alkylresorcinol content in the composition is 5.5 mass% or more. [Effects of the Invention]

[0014] The present invention provides a method for producing a highly pure alkylresorcinol-containing fat-soluble composition that contains alkylresorcinol as a fat-soluble component derived from the bran of a grass family grain and has an alkylresorcinol concentration of more than 5 mass%, as well as the fat-soluble composition. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will now be described in further detail. <Alkylresorcinol-containing fat-soluble composition> (Alkylresorcinol) The alkylresorcinol-containing fat-soluble composition of the present invention comprises an alkylresorcinol.

[0016] Alkylresorcinols are lipophilic substances having alkyl groups at the 2-, 4-, 5-, and / or 6-positions of the aromatic ring of resorcinol (1,3-dihydroxybenzene). They are commonly found in plants belonging to the Anacardiaceae, Ginkgoceae, Proteaceae, Ardisiaceae, Primulaceae, Myristicae, Iridaceae, Araceae, Fabaceae, and Poaceae families, as well as in plants such as Artemisia of the Asteraceae family. Among these plants, grasses such as wheat, rye, barley, oat, rice, millet, foxtail millet, barnyard millet, and corn contain relatively large amounts of alkylresorcinols in their edible parts (seeds), and therefore can be suitably used as raw materials for the alkylresorcinol-containing fat-soluble composition of the present invention. For example, the bran and whole grains of edible parts (seeds) of wheat, rye, etc. contain about 0.015 to 0.3 mass % of alkylresorcinols represented by the following formula (I). Fermented products such as miso paste made from wheat or rye are also suitable examples of suitable raw materials for the alkylresorcinol-containing fat-soluble composition of the present invention.

[0017] The bran of the grass cereal is preferably obtained by dehulling the grains of the grass cereal two or more times in stages and collecting a fraction between the pericarp and the husk on the outer side of the aleurone layer. Preferably, 1.5 to 3.5 mass% of the grass cereal grains are removed per dehulling. The fraction between the pericarp and the husk on the outer side of the aleurone layer, in which alkylresorcinols are localized, is preferably a fraction obtained from the first to fifth dehullings, more preferably a fraction obtained from the second and third dehullings, and is used as a raw material for the alkylresorcinol-containing fat-soluble composition of the present invention.

[0018] Examples of the alkylresorcinol include 4-butylresorcinol (rucinol), 4-hexylresorcinol, phenylethylresorcinol, and 1-(2,4-dihydroxyphenyl)-3-(2,4-dimethoxy-3-methylphenyl)-propane.

[0019] The alkylresorcinol of the present invention typically includes alkylresorcinol represented by the following formula (I):

[0020] [ka]

[0021] In formula (I), R1 represents a saturated or unsaturated, linear or branched alkyl group. The number of carbon atoms in the alkyl group represented by R1 is not limited, but is preferably 1 to 237, more preferably 3 to 27, and even more preferably 5 to 27.

[0022] In formula (I), R1 is preferably a saturated or unsaturated linear alkyl group, more preferably a saturated linear alkyl group. Examples of the saturated linear alkyl group represented by R1 include methyl, n-propyl, n-pentyl, n-heptyl, n-nonyl, n-undecyl, n-tridecyl, n-pentadecyl, n-heptadecyl, n-nonadecyl, n-henicosyl, and n-tricosyl.

[0023] In formula (I), the position and number of unsaturated bonds in the unsaturated linear alkyl group represented by R1 are not particularly limited. Examples of the unsaturated linear alkyl group include the above-mentioned saturated linear alkyl groups having an unsaturated bond at any position on the carbon chain. In formula (I), the position and number of branches of the saturated or unsaturated branched alkyl group represented by R1 and the position and number of unsaturated bonds are not particularly limited.

[0024] Preferred examples of the compound of the above formula (I) include the following. 5-Pentylresorcinol [olivetol, or 1,3-dihydroxy-5-n-pentylbenzene (C5:0)] 5-heptylresorcinol [or 1,3-dihydroxy-5-n-heptylbenzene (C7:0)] 5-Nonylresorcinol [or 1,3-dihydroxy-5-n-nonylbenzene (C9:0)] 5-Undecylresorcinol [or 1,3-dihydroxy-5-n-undecylbenzene (C11:0)] 5-Tridecylresorcinol [or 1,3-dihydroxy-5-n-tridecylbenzene (C13:0)] 5-pentadecylresorcinol [or 1,3-dihydroxy-5-n-pentadecylbenzene (C15:0)] 5-heptadecylresorcinol [or 1,3-dihydroxy-5-n-heptadecylbenzene (C17:0)] 5-Nonadecylresorcinol [or 1,3-dihydroxy-5-n-nonadecylbenzene (C19:0)] 5-heneicosylresorcinol [or 1,3-dihydroxy-5-n-heneicosylbenzene (C21:0)] 5-tricosylresorcinol [or 1,3-dihydroxy-5-n-tricosylbenzene (C23:0)] 5-Pentacosylresorcinol [or 1,3-dihydroxy-5-n-pentacosylbenzene (C25:0)] 5-heptacosylresorcinol [or 1,3-dihydroxy-5-n-heptacosylbenzene (C27:0)]

[0025] The alkylresorcinol-containing fat-soluble composition of the present invention also contains fat-soluble components other than alkylresorcinol contained in the bran of a grass family grain. The alkylresorcinol content in the alkylresorcinol-containing fat-soluble composition of the present invention is 5.5% by mass or more, preferably 6% by mass or more, and more preferably 7% by mass or more. There is no particular upper limit to the content, but in practice it is 20% by mass or less.

[0026] The alkylresorcinol-containing fat-soluble composition of the present invention may be in the form of a solid such as a powder, a gel, or a solution dissolved in a solvent, and is preferably in the form of a gel.

[0027] The solvent may be Hydrocarbons such as n-hexane, benzene, toluene, etc.; lower alcohols such as methanol, ethanol, n-propanol, isopropanol, and n-butanol; Polyhydric alcohols such as 1,3-butylene glycol, propylene glycol, and glycerin; ethers such as diethyl ether and propyl ether; esters such as butyl acetate and ethyl acetate; ketones such as acetone and methyl ethyl ketone; Examples of the solvent include oils and fats, and organic solvents such as hexane and chloroform. One or more of these solvents can be used.

[0028] Examples of the oils and fats include those commonly used in the food industry, such as medium-chain fatty acid (MCT) oil, salad oil, palm oil, palm olein, palm stearin, lard, beef tallow, milk fat, coconut oil, palm kernel oil, rapeseed oil, soybean oil, corn oil, rice bran oil, cottonseed oil, sunflower oil, sesame oil, olive oil, fractionated oils thereof, hydrogenated oils, and interesterified oils. These oils and fats may be used alone or in combination of two or more.

[0029] The solvent used in the present invention preferably contains at least one selected from the group consisting of fats and oils, ethanol, and n-hexane, more preferably at least one selected from the group consisting of ethanol and n-hexane, and even more preferably n-hexane. The proportion of the at least one selected from the group consisting of fats and oils, ethanol, and hexane in the total amount of the solvent used in the present invention is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass.

[0030] <Method for producing alkylresorcinol-containing fat-soluble composition> The method for producing the alkylresorcinol-containing fat-soluble composition of the present invention (hereinafter sometimes referred to as the production method of the present invention) includes a fat-soluble component extraction step in which an ethanol-containing solvent is mixed with bran of a grass family grain to elute the fat-soluble components in the bran, and a solution containing the fat-soluble components is recovered.

[0031] The content of ethanol in the ethanol-containing solvent is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0032] The production method of the present invention includes an alkali treatment step in which an alkali is added to the solution obtained in the fat-soluble component extraction step to adjust the pH to 10 or higher. The alkali is not limited to a specific alkali. Examples of the alkali include alkali metal hydroxides, alkaline earth metal hydroxides, and salts thereof. The alkali may be solid or liquid, and is preferably added as an aqueous solution.

[0033] The alkali metal of the alkali metal hydroxide preferably includes at least one selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, and francium, more preferably includes at least one selected from the group consisting of lithium, sodium, and potassium, even more preferably includes at least one selected from the group consisting of sodium and potassium, and particularly preferably includes sodium or potassium.

[0034] The alkaline earth metal of the alkaline earth metal hydroxide preferably contains at least one selected from the group consisting of beryllium, magnesium, calcium, strontium, and barium, more preferably contains at least one selected from the group consisting of magnesium, calcium, and barium, even more preferably contains at least one selected from the group consisting of magnesium and calcium, and particularly preferably contains calcium.

[0035] If the pH of the solution prepared in the alkali treatment step is less than 10, the -OH group in formula (I) above may not be sufficiently ionized, and the amount of alkylresorcinol dissolved in the ethanol-containing solvent phase in the fat-soluble unnecessary component removal step described below may be reduced.

[0036] The production method of the present invention includes a fat-soluble unnecessary component removal step in which n-hexane is added to and mixed with the solution obtained in the alkali treatment step, and a separation operation is performed to separate an n-hexane phase containing fat-soluble unnecessary components other than alkylresorcinols from the ethanol-containing solvent phase. The fat-soluble unnecessary components other than alkylresorcinols in the solution obtained in the alkali treatment step migrate to the n-hexane phase, and the alkylresorcinols in the solution migrate to the ethanol-containing solvent phase.

[0037] The production method of the present invention includes a neutralization step of adding an acid to the ethanol-containing solvent phase obtained in the fat-soluble unnecessary component removal step to adjust the pH to 2 to 6. The acid is not limited to a specific acid. Examples of the acid include inorganic acids, organic acids, and salts thereof. The acid may be solid or liquid, and is preferably added as an aqueous solution.

[0038] The inorganic acid preferably includes at least one selected from the group consisting of hydrochloric acid, sulfuric acid, and nitric acid, more preferably includes hydrochloric acid, and even more preferably is hydrochloric acid.

[0039] If the pH of the solution prepared in the neutralization step exceeds 6, the ionized -OH group in formula (I) may not return to the original -OH group in the ethanol-containing solvent phase, possibly resulting in a reduced amount of alkylresorcinol dissolved in the n-hexane phase in the alkylresorcinol recovery step described below. Also, if the pH of the solution prepared in the neutralization step is less than 2, the amount of alkylresorcinol dissolved in the n-hexane phase in the alkylresorcinol recovery step described below may also be reduced.

[0040] Since the ionized --OH group in the formula (I) must be quickly restored to the --OH group, the acid used in the neutralization step is not a buffer solution.

[0041] The present invention includes a concentration step of volatilizing n-hexane from the n-hexane phase obtained in the alkylresorcinol recovery step. The concentration step is carried out, for example, by suctioning the n-hexane phase under reduced pressure with or without heating. [Example]

[0042] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0043] In the examples, various physical properties were measured or calculated as follows.

[0044] <Measurement of pH> The pH of each solution was measured using pH test paper (UNIV manufactured by Toyo Roshi Kaisha, Ltd.).

[0045] <Qualitative and Quantitative Analysis of Alkylresorcinols> Using oleitol (alkylresorcinol having a straight-chain alkyl chain with 5 carbon atoms, manufactured by Sigma-Aldrich) as an alkylresorcinol standard product and Inertsil ODS4 manufactured by GL science as an analytical column, qualitative and quantitative analysis of alkylresorcinols was carried out by high performance liquid chromatography. Regarding the quantification of oleitol and each alkylresorcinol with a different alkyl chain length, the elution positions were specified in advance, and for the measured peak areas, by multiplying with a coefficient which is the value obtained by dividing each molecular weight by the molecular weight of oleitol, they were converted.

[0046] [Example 1] To 30 g of rye bran, 120 g of an ethanol-based solvent (ethanol content 99.5% by mass) composed of ethanol and water was added, and it was stirred at room temperature for 2 hours. Then filtration was carried out to perform solid-liquid separation and a filtrate was obtained. While stirring the filtrate, 30 mL of a 0.1 M aqueous sodium hydroxide solution was added, the pH of the filtrate was adjusted to 12.6, and stirring was continued until the color of the filtrate changed from yellow to a turbid ocher color. The turbid filtrate was transferred to a 500 mL separatory funnel, 200 mL of n-hexane was added, and liquid separation was carried out. It was separated into two layers, an n-hexane layer and an ethanol layer (containing ethanol and water), and the n-hexane layer was removed. The separated ethanol layer was transferred to a 500 mL separatory funnel, 200 mL of n-hexane was added, and a second liquid separation was carried out. It was separated into two layers, an n-hexane layer and an ethanol layer (containing ethanol and water), and the n-hexane layer was removed.

[0047] The ethanol layer separated in the second separation was stirred, and 31 mL of 0.1 M hydrochloric acid was added to adjust the pH of the ethanol layer to 4.0 for neutralization. The color of the ethanol layer changed from a cloudy ochre to yellow, and stirring was continued until the cloudiness disappeared. The yellow ethanol layer was transferred to a 500 mL separatory funnel, and 200 mL of n-hexane was added to separate the layers. The n-hexane layer and the ethanol layer (containing ethanol and water) separated into two layers, and the n-hexane layer was collected and saved. The separated ethanol layer was transferred to a 500 mL separatory funnel, and 200 mL of n-hexane was added to separate the layers again. The n-hexane layer and the ethanol layer (containing ethanol and water) separated into two layers. The separated ethanol layer was removed, and the n-hexane layer was collected.

[0048] The recovered n-hexane layer was transferred to a recovery flask, and the pressure was reduced using an evaporator to volatilize the n-hexane, yielding 170.3 mg of a gel-like alkylresorcinol-containing composition. The alkylresorcinol content in the fat-soluble components contained in the alkylresorcinol-containing composition was 17.8% by mass. The recovery rate of alkylresorcinol from the alkylresorcinol-containing composition relative to the alkylresorcinol in the filtrate after solid-liquid separation was 78.3%.

[0049] [Comparative Example 1] To 30 g of rye bran, 120 g of an ethanol-based solvent (ethanol content: 99.5% by mass) consisting of ethanol and water was added, and the mixture was stirred at room temperature for 2 hours. The mixture was then filtered, and solid-liquid separation was performed to obtain a filtrate. The filtrate was transferred to a recovery flask and reduced pressure using an evaporator to obtain 2.0 g of an alkylresorcinol-containing composition. The alkylresorcinol content in the alkylresorcinol-containing composition was 5.1% by mass.

Claims

1. A fat-soluble component extraction step of mixing the bran of a grass family grain with an ethanol-containing solvent to elute fat-soluble components in the bran and recovering a solution containing the fat-soluble components; an alkali treatment step of adding an alkali to the solution obtained in the fat-soluble component extraction step to adjust the pH to 10 or more; a fat-soluble unnecessary component removal step of adding and mixing n-hexane to the solution obtained in the alkali treatment step, and separating the n-hexane phase containing fat-soluble unnecessary components other than alkylresorcinols from the ethanol-containing solvent phase by a liquid separation operation; a neutralization step of adding an acid to the ethanol-containing solvent phase obtained in the fat-soluble unnecessary component removal step to adjust the pH to 2 to 6; an alkylresorcinol recovery step of adding and mixing n-hexane to the ethanol-containing solvent phase obtained in the neutralization step, and separating the ethanol-containing solvent phase from an n-hexane phase containing alkylresorcinol by a liquid separation operation; A method for producing an alkylresorcinol-containing fat-soluble composition, comprising a concentration step of volatilizing n-hexane from the n-hexane phase obtained in the alkylresorcinol recovery step.

2. 2. The method for producing an alkylresorcinol-containing fat-soluble composition according to claim 1, wherein the concentration step produces an alkylresorcinol-containing fat-soluble composition having an alkylresorcinol content of 5.5% by mass or more.

3. 2. The method for producing an alkylresorcinol-containing fat-soluble composition according to claim 1, wherein the acid comprises at least one selected from the group consisting of hydrochloric acid, sulfuric acid, and nitric acid.

4. A method for producing an alkylresorcinol-containing fat-soluble composition as described in claim 1, characterized in that the bran of the grass family grain is obtained by gradually peeling the grass family grain and collecting the fraction between the outer pericarp and the husk of the aleurone layer.

5. 5. The method for producing an alkylresorcinol-containing fat-soluble composition according to claim 1, wherein the bran of a cereal of the Gramineae family comprises at least one selected from the group consisting of rye bran and wheat bran.

6. An alkylresorcinol-containing fat-soluble composition comprising an alkylresorcinol as a fat-soluble component derived from the bran of a grass family grain and other fat-soluble components, wherein the alkylresorcinol content in the composition is 5.5 mass% or more.

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