阅读说明：本技术 从含谷维素的米糠油皂脚中分离提取天然阿魏酸的方法 (Method for separating and extracting natural ferulic acid from oryzanol-containing rice bran oil soapstock ) 是由 杨荣 唐克军 李荣明 秦福连 雷素梅 黄莉 于 2020-08-17 设计创作，主要内容包括：本发明公开了一种从含谷维素的米糠油皂脚中分离提取天然阿魏酸的方法,该方法是以含谷维素的米糠油皂脚为原料,并对其依序进行皂化、提取、酸沉分离、淋洗、脱色精制、干燥,最终得到含量≥98%的天然阿魏酸。该方法工序简单,损耗少,提取效率高,生产成本低,且生产过程中不使用有毒有害溶剂,对环境无污染。所得产品含量大于98%,颜色白,10%乙醇溶解澄清透亮,过0.45um滤纸无炭点；可通过国际认可的同位素检测法判定的产品天然度,符合欧美日等发达国家出口要求。(The invention discloses a method for separating and extracting natural ferulic acid from oryzanol-containing rice bran oil soapstock, which takes the oryzanol-containing rice bran oil soapstock as a raw material and carries out saponification, extraction, acid precipitation separation, leaching, decoloration, refining and drying in sequence to finally obtain the natural ferulic acid with the content of more than or equal to 98 percent. The method has the advantages of simple process, low loss, high extraction efficiency, low production cost, no use of toxic and harmful solvent, and no environmental pollution. The obtained product has a content of more than 98%, is white in color, is clear and transparent when dissolved in 10% ethanol, and has no carbon point when passing through 0.45um filter paper; the product naturalness can be judged by an internationally recognized isotope detection method, and the export requirement of developed countries such as Europe, America and the like is met.)

1. A method for separating and extracting natural ferulic acid from oryzanol-containing rice bran oil soapstock is characterized by comprising the following steps: the method comprises the following steps:

(1) saponification: adding 2-4 times of sodium hydroxide by weight of rice bran oil soapstock oryzanol, adding water to make the concentration of alkali liquor be 20% -30%, adding sodium metabisulfite with mass-volume ratio of 0.5-3% and ammonium sulfate with mass-volume ratio of 0.5-5% according to the total volume of water added in the water and raw materials, stirring and dissolving; putting the rice bran oil soapstock containing the oryzanol content into a heating reaction kettle, adjusting the temperature to 95-100 ℃, simultaneously pressurizing by inert gas, and keeping the pressure to 3-6kgf/m²Saponifying for 3-5 hours under high-speed stirring;

(2) extraction: after saponification is finished, recovering carbon dioxide gas for next recycling, adding purified water with 2-4 times of the volume of the raw materials, stirring and extracting for 30min, naturally filtering by using a 100-mesh screen, adding 8-12% alkali liquor with 2 times of the weight of the raw materials into filter residues, extracting for 1-2 h, naturally filtering by using a 100-mesh screen, cooling the filtrate to room temperature, performing plate-and-frame filter pressing, and removing impurities to obtain sodium ferulate saponified solution and saponified residues;

(3) acid precipitation separation: transferring the saponified solution to a ceramic reaction kettle, starting condensed water to stir with the ceramic reaction kettle, adjusting the pH of the saponified solution to 3-6 with 25-35% dilute sulfuric acid, setting the temperature to be less than 60 ℃ in the acid adjusting process, rapidly cooling to 15-25 ℃, centrifuging with a three-foot cloth bag, and collecting precipitates to obtain a ferulic acid crude product; standing the filtrate at 25 deg.C for 12 hr to separate out most of crystal, and vacuum filtering to obtain white sodium sulfate;

(4) leaching: adding 2-5 times of purified water according to the weight of the crude product to carry out leaching on the crude product, and removing sodium sulfate brought out in acid precipitation;

(5) decoloring and refining: adding purified water into a stainless steel tank, heating to 90-95 ℃, adding one or 2 antioxidants of 0.5-3% of vitamin C or 0.5-3% of sodium metabisulfite in the volume of the solution, adding 1/30-1/50 in the volume of the solution, adding the ferulic acid crude product after being washed by the step (3), after completely dissolved, adding activated carbon accounting for 8-15% of the weight of the crude product, stirring for 5-10 minutes, passing through a carbon rod while hot, rapidly cooling the filtrate to below 25 ℃ through condensed water, and standing to separate out crystals;

(6) and (3) drying: and (3) carrying out suction filtration on the crystallization liquid after crystals are separated out in the step (5) by using medium-speed filter paper, adding a small amount of purified water into a filter cake for cleaning, recycling the mother liquid for 2-3 times, and drying the filter cake at the temperature of below 65 ℃ to obtain the natural ferulic acid.

2. The method of claim 1, further comprising: and (3) adding 8-12% of alkali liquor in the step (2), wherein the concentration of the alkali liquor is less than 8%.

3. The method of claim 1, further comprising: the dry content of the product after the washing in the step (4) is more than or equal to 85 percent.

4. The natural ferulic acid which has the content of more than or equal to 98 percent, the recovery rate of more than or equal to 80 percent, clear ethanol dissolution color, no carbon point and satisfactory naturalness and is separated and extracted by the method of any one of claims 1 to 3.

Technical Field

The invention relates to a plant extraction and separation technology, in particular to a method for preparing natural ferulic acid with extraction content more than or equal to 98% by using rice bran oil soapstock containing oryzanol as a raw material.

Background

Ferulic acid (Ferulic acid) is a kind of phenolic acid, and is widely found in natural plants. Often cross-linked with lignin and polysaccharides constitute part of the cell wall of plants, rarely in a free state. The chemical name of the derivative is 4-hydroxy-3-methoxy cinnamon, the derivative of cinnamic acid (namely cinnamic acid, 3-phenyl-2-acrylic acid) has cis-form and trans-form structures. Trans-ferulic acid is a white to yellowish crystal, cis is a yellow oil, often in the form of a square crystal or a fibrous crystal, generally referred to as its trans-form.

The structural formula is as follows:

the molecular formula is as follows: C10H10O4

CAS number: 1135-24-6

Molecular mass: 194.18

Melting point: 169 to 173 DEG C

Physical properties; ferulic acid is soluble in hot water, slightly soluble in cold water and less stable in aqueous alkali solution; can form sodium salt and has good pH stability. Is easily soluble in methanol, ethanol and acetone, and insoluble in benzene petroleum ether. Is easy to decompose under the action of light.

Ferulic acid has strong oxidation resistance, and can well remove hydrogen peroxide, hydroxyl free radical, superoxide free radical and nitroso peroxide. It also has physiological function regulating effect, and can inhibit free radical producing enzyme and increase free radical eliminating enzyme activity. Besides, ferulic acid has the effects of resisting bacteria and diminishing inflammation, preventing and treating coronary heart disease, protecting female ovaries, inhibiting liver damage and the like, and is an internationally recognized cancer prevention substance in recent years. Ferulic acid is easily absorbed by human body, can be metabolized and discharged from urine, has low toxicity and safe use, and has more and more important medicinal value.

The natural ferulic acid from rice bran is also mainly used as a raw material for producing natural vanillin, is the only internationally accepted raw material for producing natural vanillin by a microbiological method at present, and can pass a natural degree test of isotope identification. At present, rice bran oil soapstock oryzanol sold by rice bran oil manufacturers basically has the content of 15-30 percent.

The research on ferulic acid is more in China, but the prior industrial production of natural ferulic acid is mainly obtained by alkaline hydrolysis and refining. There are many patents reporting that the method for preparing natural ferulic acid from rice bran oil processing waste or leftover soapstock also can be used for extracting natural ferulic acid from waste liquid in the preparation process of other plant dietary fibers; through searching, the relevant documents are as follows:

chinese patent CN 20101016926 discloses a process for separating and extracting natural ferulic acid with content more than or equal to 98% from waste of rice bran oil processing, which is characterized in that: the method takes the waste generated in the processing process of rice bran oil as a raw material, and prepares a white powder product with the natural ferulic acid content of more than or equal to 98 percent by ethanol washing → saponification and filtration → acidification and filtration → ethanol dissolution and filtration → ion exchange resin refining → decolorization → concentration → suction filtration → vacuum drying. The patent adopts high-temperature concentrated alkaline aqueous solution to hydrolyze oryzanol into ferulic acid in a non-dissolved state, the reaction conditions are severe, and the conversion effect is slightly poor: ferulic acid is refined by adopting ion exchange resin, is unstable under alkaline conditions and is easy to oxidize and deteriorate, and the treated resin generates more waste water and pollutes the environment.

Chinese patent CN2013105315669 discloses a process for extracting more than or equal to 98% of natural ferulic acid from leftovers of processed rice bran oil, which specifically comprises the steps of using the leftovers of the processed rice bran oil as extraction raw materials, degreasing and decoloring with n-hexane, and deodorizing with more than 80% of edible ethanol: then saponifying for 2 times by using a sodium hydroxide aqueous solution with certain concentration and temperature, naturally filtering by using a stainless steel filter screen, adjusting the saponified solution by using dilute sulfuric acid, and performing suction filtration: adjusting the pH of the precipitate to 9-10 by using dilute alkali, refining by using ion exchange resin, eluting impurities, desorbing by using an alkali alcohol solution, decoloring and filtering: the filtrate passes through a resin column to remove harmful metal ions; separating ethanol from the effluent by pervaporation membrane technology, recrystallizing the product, and washing, filtering and vacuum drying the crystallized product to obtain the product. In the patent, oryzanol is hydrolyzed into ferulic acid by adopting high-temperature concentrated alkali solution, the amount of the needed alkali solution is large, and the hydrolysis time is long; ferulic acid is refined by adopting ion exchange resin, is unstable under alkaline conditions and is easy to oxidize and deteriorate, and the treated resin generates more waste water and pollutes the environment.

Chinese patent 201911358319.0 discloses a method for preparing natural ferulic acid by taking soapstock containing oryzanol as a raw material, which comprises the following steps: the natural ferulic acid is prepared by alkali alcohol hot-melt filtration, acid precipitation separation, normal-temperature organic solvent decolorization, alkali alcohol hot reflux hydrolysis, cold separation, acidification and cold desalination, ultrafiltration membrane refining, alumina decolorization, solvent recovery and solid-liquid separation, drying and the like. The method comprises the steps of firstly increasing the content of oryzanol in raw materials to 50-70%, then carrying out hot-melt reflux hydrolysis by using an alkaline alcohol solvent, and obtaining high-purity pure white natural ferulic acid through the synergistic effect of oryzanol purification and decolorization before hydrolysis and ferulic acid alcohol solution refining and decolorization after hydrolysis. Has the advantages of high yield, high purity, complete decolorization and low requirement on raw materials; but the method has the disadvantages of complicated process, long production period and obviously increased production cost because the solvent is used to increase the oryzanol content and then the resin is decolored and refined.

Chinese patent CN201910799833.1 discloses a simple method for extracting and purifying ferulic acid from green wheat bran, which comprises the following steps: crushing green wheat kernel bran serving as a raw material, and then soaking the crushed green wheat kernel bran at room temperature by using a certain feed-liquid ratio (g/ml) and alkali liquor mass fraction for extraction; then centrifuging the water extract, adjusting the pH value to acidity, performing suction filtration, repeatedly extracting with ethyl acetate, collecting an organic phase, and performing rotary evaporation to recover ethyl acetate: dissolving ferulic acid in the dry matter with boiling distilled water, freeze drying, crystallizing, and collecting to obtain high purity ferulic acid. The patent is soaked with alkaline solution at room temperature, the extraction efficiency is low, and whether effective extraction can be carried out needs to be further proved: through simple extraction and distilled water crystallization, the obtained ferulic acid has low purity, and the application in high-end markets is limited: and the freeze drying cost is extremely high, and the economic feasibility is not realized.

Chinese patent CN201310713194.5 discloses a method for extracting ferulic acid from waste liquid generated in the preparation process of corn bran dietary fiber. The method comprises the following steps: centrifuging the waste liquid, concentrating and steaming, and adjusting the pH value of the waste liquid after removing impurities and ethanol by using concentrated hydrochloric acid; adsorbing the acidified waste liquid by using macroporous adsorption resin; eluting the saturated resin with ferulic acid by adopting ethanol: concentrating the eluate, extracting with ethyl acetate, collecting ester phase, concentrating under reduced pressure, and volatilizing ethyl acetate to obtain the final product. In the patent, a simple macroporous adsorption resin adsorption and ethyl acetate extraction process is adopted, so that a high-purity ferulic acid product is difficult to obtain.

Chinese patent CN201310553863.7 discloses a ferulic acid purification process, which mainly comprises the steps of preparing ferulic acid extract, removing solvent in the solution, purifying alkali liquor, purifying ferulic acid, preparing ferulic acid crystals, preparing finished ferulic acid products and the like. The method takes an associated product or/and crude YY-oryzanol in the process of producing rice fatty acid by rice bran as a raw material to prepare the ferulic acid extracting solution, and then purifies the ferulic acid extracting solution by a membrane combined purification process to obtain a finished product of the ferulic acid. This patent has utilized high concentration alkali waste, can realize with membrane technology, whether have the membrane can be able to bear the strong alkali, needs further to demonstrate: whether white ferulic acid with the content of 98 percent can be directly obtained by the membrane process or not and the product recovery rate can reach, further evidence is required.

Chinese patent CN201310196719.2 discloses a method for preparing ferulic acid, which comprises the following steps: extracting a cellulosic raw material by using a low-concentration alkaline alcohol-water mixed solution to obtain alkaline hydrolysis liquid containing ferulic acid, then removing soluble macromolecular impurities by ultrafiltration, concentrating ultrafiltration permeate by nanofiltration, acidifying the concentrated solution, standing at a low temperature for crystallization or extracting by an organic solvent to obtain a ferulic acid product, wherein the patent uses the low-concentration alkaline alcohol-water mixed solution to extract the ferulic acid, and needs further evidence on how to extract the ferulic acid, whether the ultrafiltration and the nanofiltration have a membrane capable of bearing the pH value of the alkaline hydrolysis liquid or not;

chinese patent CN201310191601.0 discloses a method for preparing ferulic acid. The method specifically comprises the following steps: s1. mixing the cellulose raw material with NaOH-ethanol-water solution, stirring, treating at 65-75 deg.C for 1-3 hr, filtering, and concentrating to obtain ferulic acid extractive solution: and s2, performing ultrafiltration on the ferulic acid extract in the step I by using ultrafiltration equipment with the molecular weight cutoff of 1000-10000, and performing nanofiltration treatment on the ultrafiltered filtrate, wherein the nanofiltration conditions are as follows: nanofiltration membranes with molecular interception amount of 100-180 and effective interception area of 0.2-0.3 m are adopted; s3, crystallizing the trapped fluid subjected to nanofiltration of S2 at the temperature of 1-5 ℃ and the pH value of 1.0-3.0, and performing suction filtration, washing crystals and drying to obtain ferulic acid solid. The patent uses low-concentration alkaline alcohol-water mixed solution to extract ferulic acid, and needs further evidence on how to extract the efficiency, whether ultrafiltration and nanofiltration have membranes capable of bearing the pH value of alkaline hydrolysis liquid.

Chinese patent CN202010289498.3 discloses a method for separating and purifying ferulic acid from rice bran oil refining soapstock, which comprises the steps of carrying out alkaline hydrolysis and filtration on the rice bran oil refining soapstock, injecting the obtained filtrate into a dynamic axial compression column, taking 70-90% volume fraction ethanol solution as a mobile phase, carrying out on-line detection after balancing for 20-30min, collecting eluent corresponding to chromatographic peaks, concentrating, crystallizing and drying the eluent to obtain a finished product. The recovery rate of the product produced by the patent is still a few points, but the process is complex, a resin column is used, the production period is long, the cost is high, an ultraviolet detector is required to be used for monitoring at any time in the production process, a laboratory can be used for preparing small samples, and the method is not suitable for industrial large-scale production.

Disclosure of Invention

Aiming at the defects of low efficiency, environmental pollution, complex treatment process and the like of extracting and preparing natural ferulic acid in the prior art, the invention provides a method for separating and extracting natural ferulic acid with the content of more than or equal to 98 percent by taking rice bran oil soapstock containing oryzanol as a raw material.

The technical method for realizing the aim of the invention is as follows:

a method for separating and extracting natural ferulic acid from oryzanol-containing rice bran oil soapstock comprises the following steps:

(1) saponification: rice bran oil soapAdding 2-4 times of sodium hydroxide by weight of oryzanol, adding water to make the concentration of the alkali liquor be 20% -30%, adding sodium metabisulfite with the mass-volume ratio of 0.5-3% and ammonium sulfate with the mass-volume ratio of 0.5-5% according to the total volume of the added water and the water carried in the raw materials, stirring and dissolving; putting the rice bran oil soapstock containing the oryzanol content into a heating reaction kettle, adjusting the temperature to 95-100 ℃, simultaneously pressurizing by inert gas, and keeping the pressure to 3-6kgf/m²Saponifying for 3-5 hours under high-speed stirring;

(2) extraction: after saponification is finished, recovering carbon dioxide gas for next recycling, adding purified water with 2-4 times of the volume of the raw materials, stirring and extracting for 30min, naturally filtering by using a 100-mesh screen, adding 8-12% alkali liquor with 2 times of the weight of the raw materials into filter residues, extracting for 1-2 h, naturally filtering by using a 100-mesh screen, cooling the filtrate to room temperature, performing plate-and-frame filter pressing, and removing impurities to obtain sodium ferulate saponified solution and saponified residues;

(3) acid precipitation separation: transferring the saponified solution to a ceramic reaction kettle, starting condensed water to stir with the ceramic reaction kettle, adjusting the pH of the saponified solution to 3-6 with 25-35% dilute sulfuric acid, setting the temperature to be less than 60 ℃ in the acid adjusting process, rapidly cooling to 15-25 ℃, centrifuging with a three-foot cloth bag, and collecting precipitates to obtain a ferulic acid crude product; standing the filtrate at 25 deg.C for 12 hr to separate out most of crystal, and vacuum filtering to obtain white sodium sulfate;

(4) leaching: adding 2-5 times of purified water according to the weight of the crude product to carry out leaching on the crude product, and removing sodium sulfate brought out in acid precipitation;

(5) decoloring and refining: adding purified water into a stainless steel tank, heating to 90-95 ℃, adding one or 2 antioxidants of 0.5-3% of vitamin C or 0.5-3% of sodium metabisulfite in the volume of the solution, adding 1/30-1/50 in the volume of the solution, adding the ferulic acid crude product after being washed by the step (3), after completely dissolved, adding activated carbon accounting for 8-15% of the weight of the crude product, stirring for 5-10 minutes, passing through a carbon rod while hot, rapidly cooling the filtrate to below 25 ℃ through condensed water, and standing to separate out crystals;

(6) and (3) drying: and (3) carrying out suction filtration on the crystallization liquid after crystals are separated out in the step (5) by using medium-speed filter paper, adding a small amount of purified water into a filter cake for cleaning, recycling the mother liquid for 2-3 times, and drying the filter cake at the temperature of below 65 ℃ to obtain the natural ferulic acid with the content of more than or equal to 98 percent.

And (3) adding 8-12% of alkali liquor in the step (2), wherein the concentration of the alkali liquor is less than 8%.

In the above technical scheme:

sodium metabisulfite: molecular formula of Na2S2O5 molecular weight is 190.09 CAS No. 7681-57-4, it is white or yellow crystal powder or small crystal, it has strong SO2 smell, specific gravity is 1.4, it is dissolved in water, the aqueous solution is acidic, when it contacts with strong acid, it releases SO2 to produce corresponding salt, when it is left in air for a long time, it is oxidized into Na2S2O6, SO the product can not be stored for a long time. Above 150 ℃ SO2 is decomposed. It is often used as antioxidant.

Vitamin C, also called ascorbic acid, is a water-soluble vitamin. The molecular formula is as follows: C6H8O 6; molecular weight: 176.12, respectively; CAS number: 50-81-7; is colorless crystals; melting point: 190 ℃ and 192 ℃; the acid is oxidized and decomposed in solution, has strong reducibility and is often used as an antioxidant.

Ammonium sulfate: molecular formula (NH4)2SO4 molecular weight 132.14CAS number 7783-20-2, and is colorless crystal or white granule. Has no odor, and is used as salting-out agent and osmotic pressure regulator.

The invention has the following outstanding advantages:

1. the invention adopts high temperature and high pressure to carry out saponification reaction for 3-5 hours under high speed stirring, and compared with the traditional strong alkali saponification reaction for 8-12 hours, the invention has high conversion efficiency and short saponification time;

2. the method ensures that the saponification reaction of the alkali liquor environmental concentration is complete, and then the alkali liquor is extracted by water, compared with the traditional method of directly increasing the amount of alkali liquor saponification, the method has the advantages that the yield is the same, the usage amount of sodium hydroxide is reduced by more than 60%, the production cost is saved, and the discharge of high-concentration alkali liquor wastewater is reduced;

3. the invention adopts inert gas pressurization and antioxidant addition, has short reaction time, ensures that ferulic acid is not easy to oxidize and deteriorate, has the dry content of crude product of 85-90 percent and the recovery rate of 89-93 percent calculated according to the conversion of oryzanol into ferulic acid, and improves the recovery rate by about 8 percent compared with the direct large-time saponification of alkali liquor;

4. compared with other reagents, the direct saponification extraction is adopted, the method has the advantages that impurities are removed firstly, the oryzanol content is increased, then direct saponification reaction of high-concentration alkali liquor is carried out directly, or reflux saponification reaction of high-alcohol alkali liquor is carried out, the process is simple, the operation is easy, and the efficiency is high;

5. in the production process, no reagent is used, and the product has no problems of solvent residue and the like;

6. the content of the product obtained by the invention is more than 98 percent, the product is white in color, the product is dissolved by 10 percent ethanol, clear and bright, and no carbon point exists after the product passes through 0.45um filter paper; the product naturalness can be judged by an internationally recognized isotope detection method, and the export requirement of developed countries such as Europe, America and the like is met.

Detailed Description

The present invention will be further described with reference to the following examples.

According to the embodiment of the invention, the soapstock raw material containing oryzanol is purchased in Guangxi, the oryzanol accounts for 25 percent, the water accounts for 35 percent, the sodium hydroxide manufacturer is Xinjiang Tianye, the sulfuric acid manufacturer is Guangxi Liuhua, the water is prepared by pure water equipment in a workshop, and other required raw materials are all purchased from the market.

In the embodiment of the invention, an ultraviolet spectrophotometer (UV) is adopted to detect the oryzanol content, a liquid chromatograph (HPLC) is adopted to detect the ferulic acid content, and the naturalness verification standard is as follows: specific activity of 14C: > 14D PM/g.c; the carbon isotope 13C/12C < -35.