CN108602749B  Current Assignee  J CheilJedang Corp  2015

In the method for preparing ferulic acid of the invention, a crude extract containing ferulic acid is first obtained from corn bran. In particular, the invention is characterized in that the crude extract is obtained by alkaline extraction and can be carried out by reacting the corn bran with an alkaline solution. According to an embodiment of the present invention, the alkali extraction may show a significantly high level of ferulic acid extraction rate, compared to hot water extraction, acid extraction and enzyme extraction.
The type of the solvent for alkali extraction is not particularly limited, and an alkali solvent suitable for extracting ferulic acid under alkaline conditions can be used. Specifically, the alkali solvent may be sodium hydroxide or potassium hydroxide, but the alkali solvent is not limited thereto, and a person of ordinary skill in the art may select an appropriate solvent in consideration of the extraction rate of ferulic acid, the price of the solvent, and the like. In addition, the alkali solution may be used at a concentration of 0.5% (w/w) to 1.5% (w/w), particularly 0.75% (w/w) to 1.25% (w/w), more particularly 1% (w/w), but the concentration of the alkali solution is not limited thereto.
The alkali extraction may be performed by reacting the corn bran with an alkali solution after thoroughly mixing. Specifically, the crude extract can be prepared by contacting corn bran with an alkali solution in a ratio of 1: 3 to 1:15, and then reacting at 60 ℃ to 100 ℃ for 1 to 24 hours, more specifically, by mixing corn bran with an alkali solution at a solid-to-liquid ratio of 1:5 to 1:10, and then reacting at 65 ℃ to 95 ℃ for 1.5 to 24 hours, most specifically, by mixing corn bran with an alkali solution at a ratio of 1: 7, followed by reaction at 75 ℃ for 2 hours, but the method of obtaining the crude extract is not limited thereto.
In addition, step (a) may further comprise filtering a crude extract obtained from the above reaction to remove solids.
Step (b) involves removing starch from the crude extract obtained in step (a).
In the present invention, corn bran may be a by-product produced by the corn starch removal process, and thus residual starch may be present therein. If the starch causes viscosity during processing, it may result in reduced efficiency during recovery of the extract and subsequent separation and purification. Thus, a starch removal process may be performed to maximize extraction yield.
The starch removal process may be performed by an enzymatic reaction, particularly by enzymatically reacting the crude extract obtained in step (a) with alpha-amylase, glucoamylase or both alpha-amylase and glucoamylase, but the starch removal method is not limited thereto.
Alpha-amylase and glucoamylase refer to enzymes that catalyze the hydrolysis of starch to glucose and by reaction of these enzymes, residual starch present in the crude extract can be removed.
The specific use concentration of glucoamylase and alpha-amylase may be 0.1% (w/w) to 1.0% (w/w), more specifically 0.5% (w/w) to 1.0% (w/w), but the concentrations of glucoamylase and alpha-amylase are not limited thereto, and the enzyme concentration, reaction temperature and reaction time may be appropriately selected by one of ordinary skill in the art as long as starch can be efficiently removed from the crude extract.
The viscosity of the crude extract can be increased by a starch removal process, and by this process the recovery of the extract can be increased, and the efficiency of the separation and purification process (i.e., post-extraction process) can be increased.
Step (c) involves washing the extracted residue of the corn bran, which is used to obtain a higher extraction yield by washing the residue, taking into account the extraction characteristics of the solid feedstock.
The residue washing may be performed using 1 to 10 volumes, particularly 5 volumes of water, compared to the residual amount of corn bran, but the amount of water is not limited thereto.
The preparation method can also comprise the separation and purification of ferulic acid. That is, high purity ferulic acid can be obtained at a commercial level by performing alkali extraction of corn bran, starch removal and residue washing to extract ferulic acid at a high yield, and then separating and purifying ferulic acid.
In the present invention, the separation and purification process may be performed by various separation and purification processes known in the art, particularly, by a primary purification process using activated carbon and a secondary purification process using an adsorption resin, but the separation and purification process is not particularly limited thereto.
Since the content of ferulic acid in corn bran is less than 3%, it is important to improve the purity of commercial purification process of ferulic acid. In this regard, the present inventors compared various purification methods, and as a result, confirmed that ferulic acid can be most efficiently purified to obtain high purity by a primary purification process using activated carbon and a secondary purification process using an adsorption resin.
In the primary purification process using activated carbon, the activated carbon may be granular activated carbon or powdered activated carbon, but is not limited thereto. The activated carbon may be used in a concentration of 0.1% (w/v) to 2% (w/v), particularly, 1% (w/v) with respect to the concentration of the extract.
The purification process using activated carbon may be carried out in the following order of (1) adsorption with activated carbon using the adsorption phenomenon of ferulic acid on activated carbon, (2) washing of activated carbon with hot water to remove organic substances other than ferulic acid, (3) desorption of ferulic acid to recover ferulic acid, and (4) adjustment of pH to remove solids precipitated by pH.
The desorption may be performed using an alkaline solvent, and the alkaline solvent may be specifically sodium hydroxide or potassium hydroxide, but is not limited thereto. Further, the basic solvent may be used at a concentration of 0.01% (w/w) to 0.5% (w/w), and specifically at 0.05% (w/w) to 0.1% (w/w), but is not limited thereto.
The pH adjusting step in the primary purification process may be adjusting the pH of the process liquid separated by desorption of ferulic acid as described above to pH3-4 to remove impurities by precipitation.
The secondary purification treatment using an adsorption resin may include adsorbing the treatment liquid obtained from the primary purification process onto the adsorption resin and desorbing ferulic acid therefrom.
The type of the adsorption resin used may include, for example, PAD900, Mn100, HP20, PAD600, etc., but the resin is not particularly limited thereto.
The ferulic acid adsorbed to the adsorption resin may be desorbed using an ethanol solvent at a concentration of 15% (w/w) to 35% (w/w), specifically 20% (w/w) to 30% (w/w), more specifically 30% (w/w), but the concentration of the ethanol solvent is not limited thereto.
In addition, the method for preparing ferulic acid of the invention can further comprise crystallizing the isolated and purified ferulic acid to ensure high purity of ferulic acid in commercialization. The crystallization can be appropriately performed by a method known in the art by a person of ordinary skill in the art. For example, the crystallization may be carried out in the following order of (1) condensation of the desorption fraction, (2) hot water dissolution of the precipitate, (3) temperature-decreasing crystallization, and (4) recovery of ferulic acid crystals, but the crystallization process is not limited thereto.
Another aspect of the present invention provides ferulic acid prepared by the above method.
Detailed Description
Hereinafter, the present invention will be described in detail by way of exemplary embodiments. However, these exemplary embodiments are provided for illustrative purposes only, and are not intended to limit the scope of the present invention.
Example 1 screening method for extracting ferulic acid from corn bran
In order to select the most effective method for extracting ferulic acid (i.e. a high value-added material) by using corn bran (i.e. a byproduct generated in the corn processing process) as a raw material, hot water extraction, acid extraction, alkali extraction, enzyme extraction and the like are adopted, and the results are compared. The subsequent process is optimized based on the extraction method that exhibits the best results in the overall process.
After extraction, standard analytical methods were established to assess the content and yield of ferulic acid and by this method ferulic acid was analysed in each of the extraction solutions.
Standard analytical methods for ferulic acid are as follows:
(1) weigh 100mg of each material into three cap tubes.
: the water content of the starting material was also measured and compared with pure ferulic acid (Sigma, > 99%) as a control.
(2) 2M NaOH (5mL) was added to each cap tube, and each cap tube was sealed with a stopper.
(3) The reaction was carried out in a constant temperature water bath at 45 ℃ with intermittent stirring.
: three tubes were suggested for 10, 20 and 40 hours of hydrolysis, respectively. However, the hydrolysis time is flexible depending on the raw material.
(4) After hydrolysis, the sample is vigorously stirred, allowed to stand, and about 2 to 3mL of supernatant is collected and centrifuged.
(5) After centrifugation, the supernatant was collected and filtered through a 0.45 μm filter.
(6) The filtrate (1mL) was collected and transferred to a tube for separation and recovery of the solvent.
(7) 35% HCl (0.2mL) was added thereto to neutralize the recovered solvent (1 mL).
(8) Ethyl acetate (3mL) was added to the neutralized solvent (1mL), stirred, allowed to stand, and the supernatant was recovered. The whole process was repeated 5 times in total to recover ferulic acid.
(9) The recovered ethyl acetate (about 15mL) was dried in a vacuum centrifugal drier at 60 ℃ to completely remove the solvent.
(10) 50% MeOH (5mL) was added to the solid with solvent removed to completely dissolve the solid (standard product was used at a constant volume of 250 mL).
(11) HPLC (column: Capcellpak 18) analysis was performed without dilution.
Further, the conditions for each extraction for selecting the optimum extraction method are as follows.
(1) Acid extraction
1% of H2SO4(1L) was added to corn bran (100g) and reacted at 120 ℃ for 1.5 hours. Then, through CaCO3The resultant was neutralized and filtered. The filtrate was analyzed for ferulic acid by HPLC (column: Capcellpak 18). To determine the amount of ferulic acid destroyed by acid, a standard product of ferulic acid (Sigma,>99%) under the same acid extraction conditions (1% H)2SO4120 ℃ for 1.5 hours). In addition, to determine the amount of ferulic acid destroyed by temperature, a standard product of ferulic acid (Sigma) was used>99%) in purified sterile water at 120 ℃ for 1.5 hours, thereby determining the destruction rate of ferulic acid.
(2) Enzyme extraction
Corn bran (60 g) and sterile water (300 g) were mixed thoroughly. Then, each enzyme was added thereto at a concentration of 5%, mixed, and reacted for 15 hours while stirring in a shaking incubator at 45 ℃. After the reaction, the resultant was filtered to remove solid matter, and then the filtrate was analyzed for ferulic acid by HPLC.
(3) Alkali extraction
500 ml of 1% NaOH or 1% KOH each was added to corn bran (100g), mixed well, and reacted at 75 ℃ or 95 ℃ for 2 hours. After the reaction, the resultant was filtered to remove solid matter, and then the filtrate was analyzed for ferulic acid by HPLC.
(4) Hot water extraction
Sterile water (1L) was added to corn bran (100g) and mixed with stirring. Then, the reaction was carried out at 120 ℃, 140 ℃ and 160 ℃ for 1 hour. The resultant was filtered to remove solid matter, and the filtrate was analyzed for ferulic acid by HPLC.
The yield of ferulic acid extracted from corn bran was analyzed by the above extraction and analysis method (table 1).
[ Table 1] extraction method for screening ferulic acid extracted from corn bran
Figure BDA0001694791690000081
Figure BDA0001694791690000091
As a result, the highest yield of hot water extraction at 160 ℃ was shown to be 39%. In the case of acid extraction, the yield was shown to be about 5.8%, but in the analysis by acid destruction, the destruction was shown to be 94.17%. From these results, it was confirmed that hydrolysis of the substance occurred during the acid extraction, and thus the acid extraction was not suitable as an extraction method of ferulic acid. The enzyme extraction was performed by purchasing commercial enzymes capable of degrading the structural proteins. Ferulic acid within the biomass forms a complex structure with lignin in the form of arabinoxylan. The mechanism of ester bond degradation between lignin and arabinoxylan can be achieved by feruloyl esterase. Commercial enzymes having feruloyl esterase activity are preferably selected and extracted by the above enzyme extraction method. As a result of the extraction, the extraction yield of most enzymes was found to be poor, less than 10%. Enzyme extraction alone may have the advantage of selective extraction; however, it has been demonstrated that the energy of the enzyme alone is not sufficient to break down all the ester bonds between lignin and arabinoxylan. Alkali extraction was performed with 1% NaOH or 1% KOH. The extraction rate of each catalyst is 55.6 percent and 61.6 percent respectively, which is superior to other extraction methods.
Therefore, the present inventors examined various extraction methods and confirmed that the alkali extraction method is the most effective method for extracting ferulic acid from corn bran. In addition, it was determined that of both NaOH and KOH, the cheaper NaOH was more effective, and thus NaOH was used in subsequent experiments to optimize extraction conditions.
Example 2 establishment of optimal conditions for high-yield extraction of Ferulic acid
The present inventors have optimized extraction conditions in order to ensure high yield of ferulic acid and efficiency of the purification step after extraction. First, in order to ensure the optimum concentration of the alkaline catalyst and the reaction time, NaOH was added in different concentrations (0%, 0.5%, 0.75% and 1%) to 100g of the feedstock (corn bran), respectively. When the NaOH solution is added, the solid-to-liquid ratio of the raw material to the solution is kept between 1:5, the extraction temperature was set at 95 ℃. In addition, to determine the optimal extraction, the extraction rate of ferulic acid was confirmed by sampling at each time point. The NaOH concentration suitable for the maximum extraction rate was 1% as confirmed by the above method. From these results, it was confirmed that the extraction work was almost completed within 1.5 to 3 hours after the extraction (table 2).
[ Table 2] Ferulic acid extraction yield was varied depending on alkali concentration and time
Figure BDA0001694791690000101
Conditions that may affect the extraction yield include the solid-to-liquid ratio between the feedstock and the alkaline solution. Therefore, the present inventors have conducted experiments and confirmed the optimum ratio of the solid-to-liquid ratio of the raw material to the alkali solution. In view of commercial availability, the solid-to-liquid ratio between the raw material and the alkali solution was set to 1: 5. 1: 7 and 1: 10. The solid-liquid ratio test result proves that the solid-liquid ratio is 1: 7 and 1: the extraction yield of 10 was very similar (table 3).
[ Table 3] extraction yield was varied depending on the solid-to-liquid ratio of raw material to alkali solution
Figure BDA0001694791690000102
Figure BDA0001694791690000111
As can be seen from the above results, in view of commercial applications, the solid-to-liquid ratio of 1: 7 is effective, so that the water consumption and the waste water generation can be reduced.
In addition, in order to confirm the effect of temperature on extraction, it was confirmed that the temperature was 65 ℃ C
Figure BDA0001694791690000112
Effect of extraction yield in the temperature range of 95 ℃ (fig. 1). As shown by the results confirming the effect of temperature on extraction, the extraction rate distribution was similar in the range of 65 ℃ to 95 ℃ and the extraction rate at 1.5 hours after extraction showed a very similar distribution, as in the case of the above results. These results indicate that 1% NaOH shows most of the catalytic effect required for extraction.
Example 3 improvement of extraction yield by enzyme application technique
Corn bran is a by-product of corn processing and is a by-product after removal of corn starch, so that unremoved starch remains in the feedstock (corn bran). In this process starch provides viscosity and significantly inhibits the recovery process of the extracted extract and the post-extraction process. In this regard, the present inventors have studied a method for maximizing the extraction rate by combining an alkali extraction technique with an enzyme technique for removing starch. The method can improve the extraction rate and promote the purification process after extraction to be smoother.
To determine the effect of starch structure in the feedstock on extraction yield, alpha-amylase and glucoamylase for corn processing were used. The extraction effect was examined by setting the reaction temperature of alpha-amylase at 95 deg.c and glucoamylase at 65 deg.c while setting the enzyme concentration at 1%.
To analyze the effect of enzyme application, the following four experimental groups were constructed: (1) alkali extraction, (2) applying glucoamylase for 1 hour and extracting, (3) applying alpha-amylase for 3 hours, reacting with glucoamylase for 3 hours and extracting, and (4) applying alpha-amylase for 1 hour, reacting with glucoamylase for 1 hour, and extracting. The change in extraction rate was confirmed in the above four experimental groups (fig. 2).
The results of the experiments demonstrate that the extraction rate is significantly higher in the group using glucoamylase and alpha-amylase compared to the group performing only the extraction alone. In addition, it was confirmed that the combined use of glucoamylase and alpha-amylase is superior to the extraction using glucoamylase alone in terms of improvement of extraction yield and physical properties. This is believed to be because, as described above, the viscosity is increased by removing the starch component, and as a result, the recovery rate of the extract is increased. By this process, the efficiency of the purification process as a post-extraction process can be improved. Therefore, the present inventors have confirmed that the most important part of the process of extracting ferulic acid from corn bran is the combined use with the current enzyme technology.
In addition, to optimize the enzyme concentration, the change in extraction yield according to glucoamylase concentration was evaluated. The reaction was carried out at a glucoamylase concentration of 0.1%, 0.5% and 1.0% for 2 hours at 65 ℃. In addition, the extraction after glycosylation was performed in 1% NaOH (75 ℃).
When the extraction rate of ferulic acid was increased, the effect of glucoamylase concentration after 0.5% concentration was the same. Therefore, the present inventors were able to optimize the glucoamylase concentration to increase the ferulic acid extraction rate at 0.5%.
The yield is improved by the enzyme treatment step, and a higher extraction yield can be obtained by further washing the residue in consideration of the extraction characteristics of the solid raw material. Thus, the present inventors have confirmed the change in extraction rate caused by washing the extraction residue after extraction. To confirm the effect of post-extraction residue washing, the following four experimental groups were constructed: (1) alkali extraction; (2) washing the residue after alkali extraction; (3) treating with glucoamylase and extracting with alkali; and (4) washing the residue after glucoamylase treatment and alkaline extraction.
The results of the tests of the four experimental groups constructed as described above show that an additional ferulic acid level of about 10% can be ensured when residue washing is performed. In addition, as with the previous results, the experimental group in which glucoamylase was reacted showed an increase in yield of about 13% or more, compared to those in which glucoamylase was not reacted (fig. 4).
It has previously been demonstrated that enzymatic techniques can be used to maximize extraction yield when extracting ferulic acid from corn bran. In this regard, the inventors attempted to confirm the effect of glucoamylase before and after the alkali extraction. Further, in order to improve the recovery rate after extraction, it is expected that the extraction rate can be further improved by washing the extraction residue. For this experiment, the following two experimental groups were prepared: (1) after alkaline extraction, treatment with glucoamylase (0.5% glucoamylase, 65 ℃, 2 hours), washing of the extraction residue (5 times the amount of distilled water compared to the starting material) and (2) first treatment of corn bran with glucoamylase, alkaline extraction and washing of the extraction residue. Two experimental groups were thus prepared, and the extraction rates of the two experimental groups were evaluated (fig. 5).
The results of the experiments confirmed that the group treated with glucoamylase after the alkaline extraction had a higher extraction rate than the group treated with glucoamylase before the alkaline extraction. In this regard, the inventors were able to optimize the use of glucoamylase by alkali extraction followed by glucoamylase treatment to maximize extraction yield.
As described above, the present inventors have optimized a method for extracting ferulic acid from corn bran, which is a byproduct of corn processing, in high yield. Subsequently, the inventors of the present invention performed extraction of ferulic acid based on the above description, and performed development of a high-purity separation and purification technique using an extraction treatment solution. Further, development studies of subsequent high-purity separation and purification methods were conducted by the optimized extraction method described below. The optimized extraction method is as follows. The solid-liquid ratio of the corn bran to the water is 1: 7 (Table 3), 1% NaOH (Table 2), extracted at 75 ℃ for 2 hours (FIG. 1), and then glucoamylase (FIG. 3 and 5) was added in an amount of 0.5% (w/w) and allowed to react at 65 ℃ for 1 hour. After the enzyme reaction, the solid portion was separated by filtration and used as a treatment solution for subsequent high-purity separation and purification processes.
Example 4 development of separation and purification technique for high-purity extraction of Ferulic acid
Since the amount of ferulic acid in corn bran is less than 3%, it is very difficult to improve purity in the purification process after extraction. Therefore, the present inventors tried various methods of ferulic acid purification suitable for food-based methods, and studied purification methods with the highest efficiency and high purity.
To summarize the method of purifying extracted ferulic acid, a purification process comprising 6 steps in total and having a final purity of 98% or more was performed as follows:
1) adsorption of activated carbon: the phenomenon that ferulic acid is adsorbed on activated carbon is utilized;
2) hot water washing of activated carbon: removing organic substances except ferulic acid;
3) desorbing ferulic acid in the activated carbon: ensuring that the ferulic acid has higher purity;
4) and (3) pH adjustment: removing solids precipitated by pH;
5) adsorption and desorption of the adsorbent resin: the maximum purity is achieved by purification; and
6) powder crystallization: ensuring a product purity of 98% or higher.
(1) Process for purifying ferulic acid by activated carbon
Ferulic acid is a lignin-based organic material with structural features that are adsorbed on activated carbon. Therefore, for easy purification, the present inventors selected activated carbon under conditions that yield of adsorption and separation and purity after desorption improve optimally according to the type of activated carbon (granular activated carbon and powdered activated carbon), and attempted to apply the selected activated carbon to the process. The ferulic acid solution extracted by the optimized extraction conditions described in the above examples was used for ferulic acid purification with high efficiency and high purity.
When ferulic acid extract from corn bran is added to activated carbon (powdered activated carbon or granular activated carbon), the adsorption rate of ferulic acid is 95% or more. Specifically, in order to improve the adsorption efficiency, tests were performed using powdered activated carbon and granular activated carbon, and the adsorption level of ferulic acid in both types of activated carbon was 95% to 99%.
However, powdered activated carbon shows excellent results in the desorption process compared to granular activated carbon, and thus subsequent purification of activated carbon is performed using powdered activated carbon. The adsorption can be carried out under various temperature conditions, and the inventors finally carried out the adsorption at room temperature. In addition, in order to optimize the appropriate amount of activated carbon, the amount of activated carbon was checked at a level of 0.1% (w/v) to 2% (w/v). As a result, a suitable amount of activated carbon relative to the amount of extract was evaluated as 1% (w/v). The desorption solvent for desorbing ferulic acid adsorbed in activated carbon was evaluated based on the concentration of NaOH as an alkaline solvent (0.05% to 0.5%), and the results showed that the purity and desorption rate of the desorbed ferulic acid were similar at 0.05% NaOH and 0.1% NaOH (table 4).
[ Table 4]
Figure BDA0001694791690000141
In order to improve the purity of ferulic acid in the purification process of the activated carbon, the activated carbon is washed by hot water (90 ℃), and the principle of desorption according to temperature after organic matters in the activated carbon are adsorbed is adopted. As a result, about 11.6% of impurities were further removed after hot water washing (table 5).
[ Table 5]
Figure BDA0001694791690000142
Figure BDA0001694791690000151
This hot water washing process facilitates desorption of ferulic acid adsorbed on activated carbon by removing organic substances other than ferulic acid, and has the effect of improving purity after desorption.
Then, in order to further improve the purity of the purified ferulic acid, the inventors utilized the sedimentation effect of the residual organic substances present in the extract due to pH. When the treated solution desorbed with activated carbon was adjusted to pH3 to 4 with an acidic solution (HCl), a large amount of impurities were precipitated, and an additional 10% or more increase in purity was achieved by this adjustment (table 5). The effect of precipitating the organic substances by lowering the pH can remove the viscous substances and ensure physical properties enabling the transfer into the subsequent adsorption resin process. In addition, the purity of the ferulic acid is improved from about 2% to about 30% after extraction by the activated carbon and the method for improving the purity.
Based on these results, as conditions for primary purification of high-purity ferulic acid, 1% (w/w) powdered activated carbon was added to the extract filtrate, reacted at room temperature for 1 hour, adsorbed onto activated carbon, and washed with the same volume amount of hot water (90 ℃) of the extract (Table 5), followed by desorption with the same volume amount of 0.05% NaOH of the extract (Table 4). The separated solution was neutralized to pH3-4 with 6N HCl and the primary purified solution was obtained by filtration (table 5). The primary purified solution obtained is used as a solution for the adsorption resin process of the subsequent process.
(2) Treating high-purity ferulic acid by adsorption resin process
The extraction purity of ferulic acid obtained from the extraction process was about 1.5% to about 2.5%, and the purity of ferulic acid obtained from the activated carbon purification process was about 30% (table 5). The purity of ferulic acid which can be used as a commodity is more than 98%. For this purpose, the present inventors have performed a resin process and a crystallization process to obtain ferulic acid with high purity. The treatment solution used for the resin process was a treatment solution with a purity of 30%, which was subjected to primary purification from the extract using activated carbon (table 5).
The resin process has also been demonstrated to have the effect of an anionic resin. However, it was confirmed that the adsorption resin is superior in purity and yield of ferulic acid, and therefore high-purity treatment was performed using PAD900(Purolite) resin, which was confirmed by testing for each type of adsorption resin. The adsorption resin treatment test was performed at room temperature, where SV was maintained in the range of 3 to 6 at the time of adsorption and SV was maintained at 10 at the time of desorption. The total amount of adsorbent resin used in the test was 14 mL. The concentration of ferulic acid subjected to primary purification in activated carbon was 0.66g/L, and the adsorption capacity was 41.5 g-ferulic acid/L-resin. According to the test results of the desorption solvent (ethanol) concentration (20% to 80%), the separation pattern of high-purity (79% to 85%) ferulic acid was observed in the low-concentration ethanol desorption solvent. When the crystallinity of ferulic acid in each fraction was examined, crystallinity was observed in desorbed ferulic acid with ethanol concentrations of 20% and 30% (table 6).
[ Table 6]
Figure BDA0001694791690000161
Figure BDA0001694791690000171
The above results indirectly confirm that ferulic acid of the same purity has impurities that inhibit the crystallinity of ferulic acid even though it is desorbed at different ethanol concentrations. Therefore, the present inventors were able to optimize the ethanol concentration as desorption solvent during the adsorption resin process.
As described above, for the adsorption resin process, after adsorption onto PAD900 adsorption resin, desorption with 30% ethanol yielded high purity ferulic acid (80%). The subsequent crystallization process was carried out with reference to a treatment solution with a purity of 80%, which was subjected to extraction of corn bran, primary purification by activated carbon and purification by means of an adsorption resin.
(3) Ensuring the commercial purity of ferulic acid by crystallization
Ferulic acid was crystallized using the fractions of the desorption fraction described above (20% ethanol and 30% ethanol) to ensure a purity of 98% or more (commercial purity). The crystallization was carried out in the following order: 1) concentration of the desorbed fraction (10 times), 2) dissolution of the precipitate (100mL) in hot water, 3) crystallization by temperature control (cooling), and 4) recovery of ferulic acid crystals.
As a result of this procedure, the recovery rate of the input solution to the crystals by concentration precipitation was 81.8%, and the recovery rate of the crystallization rate after dissolution in hot water was 88%. The purity of the final ferulic acid was 98.7%, thus the final yield of the crystallization process was 72% recovered in commercial quality (table 7, figure 6).
[ Table 7]
Figure BDA0001694791690000172
The final purity of ferulic acid obtained by the above method was 98.7%, which was similar to the level of standard product (99%), and ferulic acid was produced as a product suitable for the 98% purity level of ferulic acid currently commercialized.
Based on these results, the present inventors have invented a method for efficiently mass-producing ferulic acid as a high value-added material using corn bran, which is an economical raw material, in the presence of various solvents (IPA, hexane, ethanol, etc.) conventionally produced using raw oil refined materials (i.e., by-products produced from existing rice bran oil preparations), as a raw material, and which is mass-produced by simple extraction, purification and crystallization processes, thereby achieving high yield.
From the above description, those skilled in the art to which the present disclosure pertains will appreciate that the present disclosure may be embodied in other specific forms without changing the technical concept or essential features of the present invention. In this regard, the exemplary embodiments disclosed herein are for illustrative purposes only and should not be construed to limit the scope of the present disclosure. On the contrary, the present disclosure is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments that are within the spirit and scope of the disclosure as defined by the appended claims.