Immunoregulatory activity octapeptide as well as preparation method and application thereof
By extracting and purifying immunomodulatory active octapeptides from rice bran, the problem of the limited availability of active peptide products from rice bran has been solved. This has enabled the preparation of high-yield and high-purity products, increasing the added value of rice bran and providing its application in immunomodulatory drugs, foods, and health products.
Patent Information
- Application Number
- CN202510870724.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-26
- Publication Date
- 2025-10-31
AI Technical Summary
In the existing technology, there are few high-activity rice bran active peptide products, and there is a lack of effective preparation processes and structural identification, which limits the high-value utilization of rice bran.
An immunomodulatory active octapeptide with the amino acid sequence Val-Val-Pro-Arg-Phe-His-Pro-Met was prepared by extracting and purifying an immunomodulatory active octapeptide from rice bran through specific steps including dissolution, precipitation, enzymatic hydrolysis, membrane separation, and reverse chromatography purification of rice bran protein.
The preparation of immunomodulatory active octapeptides with high yield and high purity was achieved, which increased the added value of rice bran and provided its application in immunomodulatory drugs, food and health products, and it has significant immunomodulatory activity.
Smart Images
Figure CN120865335A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of medicine, specifically relating to an immunomodulatory active octapeptide, its preparation method, and its application. Background Technology
[0002] Bioactive peptides are important functional food ingredients with bioactivities such as immune regulation, antioxidation, and osteoporosis prevention. They are widely used in the production of health foods and other food products and are very popular with consumers. Rice bran is a complex composed of pericarp, seed coat, aleurone layer, and embryo during the rice milling process. It is rich in protein (12%-15%), fat (16%-20%), dietary fiber (14%), and bioactive substances such as γ-oryzanol, tocopherol, and phytic acid. Rice bran protein bioactive peptides exhibit significant physiological regulatory functions due to their unique amino acid sequence and spatial conformation. Existing studies have confirmed that rice bran protein bioactive peptides mainly possess bioactivities such as antioxidation, blood pressure reduction, immune regulation, and low allergenicity. Although there are many reports on rice bran bioactive peptides, products with high bioactive peptide activity are still rare. Therefore, it is necessary to conduct research on the preparation process, structural identification, and activity evaluation of rice bran bioactive peptides to reveal the chemical structure of the main bioactive peptides. This is of great significance for the high-value utilization of rice bran. Summary of the Invention
[0003] The first objective of this invention is to provide an immunomodulatory active octapeptide isolated from rice bran protein.
[0004] The immunomodulatory active octapeptide of the present invention has the following amino acid sequence: Val-Val-Pro-Arg-Phe-His-Pro-Met.
[0005] A second objective of this invention is to provide the application of the above-mentioned immunomodulatory octapeptide in the preparation of immunomodulatory drugs, foods, or health products.
[0006] Preferably, the drug contains pharmaceutically usable excipients.
[0007] Preferably, the drug can be formulated into various available dosage forms, such as powder, injection, suspension, etc.
[0008] A third objective of this invention is to provide an immunomodulatory active drug, food, or health product containing the aforementioned immunomodulatory active octapeptide as an active ingredient.
[0009] A third objective of this invention is to provide a method for preparing an immunomodulatory active octapeptide, characterized in that the immunomodulatory active octapeptide can be artificially synthesized or prepared by the following methods:
[0010] Rice bran was dissolved in water, and the pH was adjusted to 8. The mixture was stirred and extracted to ensure complete protein dissolution. The mixture was first coarsely filtered through gauze to remove insoluble residues, then centrifuged to collect the supernatant. The pH was adjusted to 4.5 to precipitate the protein. The precipitate was collected by centrifugation and freeze-dried to obtain rice bran protein. The rice bran protein was dispersed in water, hydrolyzed with protease, and then the enzyme was inactivated at high temperature. The supernatant of the protein hydrolysate was obtained by centrifugation, separated by membrane separation, and dried to obtain rice bran protein hydrolysate. The rice bran protein hydrolysate was purified using reverse chromatography with a gradient elution of water and ethanol-water solutions. The target active peptide was collected, concentrated, and purified using a Sephadex LH-20 column. After concentration and drying, the target immunomodulatory active octapeptide was obtained.
[0011] Preferably, red rice bran is added to distilled water at a material-to-liquid mass ratio of 1:10, and the pH is adjusted to 8.0 with 1M NaOH solution. The mixture is stirred and extracted for 2 hours to ensure complete protein dissolution. First, it is coarsely filtered through gauze to remove insoluble residues. Then, it is centrifuged at 3000 rpm for 20 minutes, and the supernatant is collected. The supernatant is then extracted with 1M NaOH solution. The pH of the supernatant was adjusted to 4.5 with HCl to precipitate the protein. The precipitate was collected by centrifugation at 3000 rpm for 20 minutes and then freeze-dried to obtain rice bran protein. The rice bran protein was dispersed in water, hydrolyzed with protease, and then the enzyme was inactivated by high temperature. The supernatant of the protein hydrolysate was obtained by centrifugation, separated by membrane separation, and dried to obtain rice bran protein hydrolysate. The rice bran protein hydrolysate was purified into active peptides by reverse chromatography column elution with a gradient of water and ethanol aqueous solution. Specifically, the volume fraction of ethanol was gradually increased from 0% to 20% in increments of 2%. The target active peptide component eluted with 8% ethanol was collected, concentrated, and purified by Sephadex LH-20 column elution with 8% ethanol aqueous solution. The target active peptide component eluted with 8% ethanol was collected, concentrated, and dried to obtain the target immunomodulatory active octapeptide.
[0012] Preferably, after adding protease for hydrolysis, the enzyme is inactivated by high temperature. The supernatant of the protein hydrolysate is obtained by centrifugation, membrane separation, and drying. The rice bran protein hydrolysate is obtained by adding 0.2%-2% alkaline protease according to the mass of rice bran protein, at pH 7.0-10.0 and temperature 35-65℃ for 1-5 hours, then adding 0.2%-2% alkaline protease, at pH 7.0-10.0 and temperature 35-65℃ for 1-5 hours, then adding 0.2%-2% neutral protease, at pH 7.0-9.0 and temperature 45-65℃ for 1-5 hours, then heating to 90℃ and holding for 20 minutes to inactivate the enzyme, centrifuging to obtain the supernatant of the protein hydrolysate, decolorizing with activated carbon, filtering with an ultrafiltration membrane with a molecular weight cutoff of 3000 Daltons, collecting the permeate and spray drying to obtain the rice bran protein hydrolysate.
[0013] A further preferred method involves adding 0.5% alkaline protease according to the mass of the rice bran protein isolate, at pH 9.5 and temperature 65°C, and hydrolyzing for 3 hours. Then, adding 0.5% neutral protease, at pH 8.0 and temperature 60°C, and hydrolyzing for 3 hours, followed by heating to 90°C and holding for 20 minutes to inactivate the enzyme. The mixture is then centrifuged at 5000g for 10 minutes to obtain the supernatant of the protein hydrolysate. This supernatant is decolorized with activated carbon, filtered using an ultrafiltration membrane with a molecular weight cutoff of 3000 Daltons, and the permeate is collected and spray-dried to obtain the rice bran protein hydrolysate.
[0014] Preferably, the rice bran protein is dispersed in water by adding rice bran protein to 5-20 times its weight of water and then stirring to disperse it.
[0015] The fifth objective of this invention is to provide the use of rice bran in the preparation of the above-mentioned immunomodulatory active octapeptide.
[0016] This invention discloses a method for preparing immunomodulatory octapeptides from rice bran, with a yield of 30-70 g / kg (purity of 70-95%). These octapeptides exhibit good immunomodulatory activity and can be applied to the preparation of immunomodulatory drugs, foods, or health products. This invention provides a novel method for the preparation of immunomodulatory octapeptides, which is of great significance for the deep processing and utilization of rice bran, increasing its added value, and promoting the sustainable development of the industry. Attached Figure Description
[0017] Figure 1 It is a secondary mass spectrometer of immunomodulatory peptides;
[0018] Figure 2 It refers to the amount of NO produced by macrophages induced by immunomodulatory peptides. Detailed Implementation
[0019] The following embodiments are further illustrations of the present invention, but not limitations thereof.
[0020] Example 1: Preparation, isolation, and structural identification of an immunomodulatory octapeptide
[0021] I. Preparation and Isolation of Immunologically Active Peptides
[0022] 1) Selection of raw materials: Choose red rice bran.
[0023] 2) Preparation: Add 10 times the mass of water to the rice bran, then stir to disperse and obtain a mixture.
[0024] 3) Preparation of rice bran protein: Adjust the pH of the mixture to 8.0 with 1M NaOH solution, extract for 2 hours with stirring, first coarsely filter with gauze to remove insoluble residue, then centrifuge at 3000 r / min for 20 minutes to remove insoluble precipitate. Collect the supernatant, adjust the pH to 4.5 with 1M hydrochloric acid, centrifuge at 3000 r / min for 20 minutes to collect the precipitate, freeze-dry to obtain rice bran protein.
[0025] 4) Extraction: Add 50g of rice bran protein to 500mL of water, then stir to disperse and obtain rice bran protein isolate.
[0026] 5) Enzymatic hydrolysis: Add 0.5% alkaline protease (Novozymes) according to the mass of rice bran protein isolate, at pH 9.5 and temperature 65℃, and hydrolyze for 3 hours. Then add 0.5% neutral protease (Novozymes), at pH 8.0 and temperature 60℃, and hydrolyze for 3 hours. Raise the temperature to 90℃ and hold for 20 minutes to inactivate the enzyme. Centrifuge (5000g, 10min) to obtain the supernatant of the protein hydrolysate. Decolorize with activated carbon (10%, w / vg / ml) for 24 hours. Filter using an ultrafiltration membrane with a molecular weight cutoff of 3000 Daltons, collect the permeate and spray dry to obtain the rice bran protein hydrolysate.
[0027] 6) Column purification: The rice bran protein hydrolysate was purified using a C18 reversed-phase column (15×460mm) with gradient elution of water and ethanol-water solutions. Specifically, the volume fraction of ethanol was gradually increased from 0% to 20% in increments of 2%. The target active peptide component eluted with 8% ethanol was collected, concentrated, and then purified using a Sephadex LH-20 column (15×460mm) with 8% ethanol-water solution. The target active peptide component eluted with 8% ethanol was collected, concentrated, and dried to obtain the target immunomodulatory active octapeptide.
[0028] The immunomodulatory octapeptide obtained by this method had a yield of 46-70 g / kg and a purity of 90%.
[0029] II. Structural Identification of Immunomodulatory Octapeptides
[0030] The immunomodulatory octapeptide is water-soluble. High-resolution liquid chromatography-mass spectrometry (LC-MS / MS) analysis of this immunomodulatory octapeptide yielded the following results: Figure 1 Based on secondary mass spectrometry information, the amino acid sequence of this immunomodulatory octapeptide was identified as: Val-Val-Pro-Arg-Phe-His-Pro-Met.
[0031] The molecular ion peak of this immunomodulatory octapeptide in cationic mode is m / z = 419.73, z = 2.
[0032] The gamma ion signals at m / z 697.34, 531.24, and 392.7 are for Arg-Phe-His-Pro-Met, Phe-His-Pro-Met, and Val-Pro-Arg-Phe-His-Pro-Met, respectively. The beta ion signals at m / z 767.37, 736.43, 599.37, and 452.3 are for Val-Val-Pro-Arg-Phe-His-Pro, Val-Val-Pro-Arg-Phe-His, Val-Val-Pro-Arg-Phe, and Val-Val-Pro-Arg, respectively. The presence of these signals confirms that the structure of this immunomodulatory octapeptide is Val-Val-Pro-Arg-Phe-His-Pro-Met. After artificial synthesis, the octapeptide was detected by liquid chromatography-mass spectrometry (LC-MS / MS), and the retention time and mass spectrometric fragmentation were found to be consistent with those of the identified substance. Therefore, the structure is determined to be the structure described above.
[0033] III. Activity Assay of Immunomodulatory Octapeptides
[0034] RAW264.7 cells in logarithmic growth phase were seeded into 96-well plates and incubated at 37°C in a CO2 incubator for 24 hours. After discarding the culture medium, DMEM medium containing different concentrations of peptides was added to the wells, while control wells were filled with culture medium without the sample. After further incubation for 24 hours, the culture medium was collected, and the release of nitric oxide (NO) was measured using a nitric oxide assay kit, with three replicates for each test. The NO concentration in the culture medium was calculated based on the standard curve, with cells without sample treatment serving as a blank control.
[0035] Experimental results are as follows Figure 2 As shown, Figure 2 The immunomodulatory activity of this immunomodulatory octapeptide was demonstrated using the amount of NO produced by macrophages as an indicator. Compared with the blank control, the immunomodulatory octapeptide produced a significant NO-promoting effect even at the lowest dosage (0.2 mg / mL), confirming its significant immunomodulatory activity. Within the dosage range of 0.2–1.5 mg / mL, the immunomodulatory activity of this octapeptide showed a clear dose-response relationship. At a dosage of 1.5 mg / mL, the NO concentration reached as high as 4.6 μM.
[0036] Example 2:
[0037] I. Preparation and Isolation of Immunologically Active Peptides
[0038] 1) Selection of raw materials: Choose red rice bran.
[0039] 2) Preparation: Add 5 times the mass of water to the rice bran, then stir to disperse and obtain a mixture.
[0040] 3) Preparation of rice bran protein: Adjust the pH of the mixture to 8.5 with 1M NaOH solution, extract for 1 hour with stirring, first coarsely filter with gauze to remove insoluble residue, then centrifuge at 3000 r / min for 20 minutes to remove insoluble precipitate. Collect the supernatant, adjust the pH to 5.0 with 1M hydrochloric acid, centrifuge at 3000 r / min for 20 minutes to collect the precipitate, freeze-dry to obtain rice bran protein.
[0041] 4) Extraction: Add 50g of rice bran protein to 500mL of water, then stir to disperse and obtain rice bran protein isolate.
[0042] 5) Enzymatic hydrolysis: Add 0.75% alkaline protease (Novozymes) according to the mass of rice bran protein isolate, at pH 8.5 and 50℃, and hydrolyze for 3 hours. Then add 0.35% neutral protease (Novozymes), at pH 7.0 and 50℃, and hydrolyze for 2 hours. Raise the temperature to 90℃ and hold for 20 minutes to inactivate the enzyme. Centrifuge (5000g, 10min) to obtain the supernatant of the protein hydrolysate. Use activated carbon (10%, w / v) for decolorization for 24 hours. Filter using an ultrafiltration membrane with a molecular weight cutoff of 3000 Daltons, collect the permeate and spray dry to obtain the rice bran protein hydrolysate.
[0043] 6) Column purification: The rice bran protein hydrolysate was purified using a C18 reversed-phase column (15×460mm) with gradient elution of water and ethanol-water solutions. Specifically, the volume fraction of ethanol was gradually increased from 0% to 20% in increments of 2%. The target active peptide component eluted with 10% ethanol was collected, concentrated, and then purified using a Sephadex LH-20 column (15×460mm) with elution of 10% ethanol-water solution. The target active peptide component eluted with 10% ethanol was collected, concentrated, and dried to obtain the target immunomodulatory active octapeptide.
[0044] The yield of the immunomodulatory octapeptide obtained by this method was 35-68 g / kg, and the purity was 85%.
[0045] Example 3:
[0046] I. Preparation and Isolation of Immunologically Active Peptides
[0047] 1) Selection of raw materials: Choose red rice bran.
[0048] 2) Preparation: Add 15 times the mass of water to the rice bran, then stir to disperse and obtain a mixture.
[0049] 3) Preparation of rice bran protein: Adjust the pH of the mixture to 9.0 with 1M NaOH solution, extract for 3 hours with stirring, first coarsely filter with gauze to remove insoluble residue, then centrifuge at 3000 r / min for 20 minutes to remove insoluble precipitate. Collect the supernatant, adjust the pH to 5.5 with 1M hydrochloric acid, centrifuge at 3000 r / min for 20 minutes to collect the precipitate, freeze-dry to obtain rice bran protein.
[0050] 4) Extraction: Add 50g of rice bran protein to 750mL of water, then stir to disperse and obtain rice bran protein isolate.
[0051] 5) Enzymatic hydrolysis: Add 1% alkaline protease (Novozymes) according to the mass of rice bran protein isolate, pH 8.5, temperature 50℃, and hydrolyze for 5 hours. Then add 1% neutral protease (Novozymes), pH 7.0, temperature 50℃, and hydrolyze for 5 hours. Raise the temperature to 90℃ and hold for 20 minutes to inactivate the enzyme. Centrifuge (5000g, 10min) to obtain the supernatant of the protein hydrolysate. Use 10% activated carbon (w / v) for decolorization and debittering. Filter using an ultrafiltration membrane with a molecular weight cutoff of 3000 Daltons. Collect the permeate and spray dry to obtain the rice bran protein hydrolysate.
[0052] 6) Column purification: The rice bran protein hydrolysate was purified using a C18 reversed-phase column (15×460mm) with gradient elution of water and ethanol-water solutions. Specifically, the volume fraction of ethanol was gradually increased from 0% to 20% in increments of 2%. The target active peptide component eluted with a volume fraction of 6% ethanol was collected, concentrated, and then purified using a Sephadex LH-20 column (15×460mm) with elution of 6% ethanol-water solutions. The target active peptide component eluted with a volume fraction of 6% ethanol was collected, concentrated, and dried to obtain the target immunomodulatory active octapeptide.
[0053] The immunomodulatory octapeptide obtained by this method had a yield of 42-60 g / kg and a purity of 95%.
[0054] Example 4:
[0055] I. Preparation and Isolation of Immunologically Active Peptides
[0056] 1) Selection of raw materials: Choose red rice bran.
[0057] 2) Preparation: Add 10 times the weight of water to the rice bran, then stir to disperse and obtain a mixture.
[0058] 3) Preparation of rice bran protein: Adjust the pH of the mixture to 8.0 with 1M NaOH solution, extract for 2 hours with stirring, first coarsely filter with gauze to remove insoluble residue, then centrifuge at 3000 r / min for 20 minutes to remove insoluble precipitate. Collect the supernatant, adjust the pH to 4.5 with 1M hydrochloric acid, centrifuge at 3000 r / min for 20 minutes to collect the precipitate, freeze-dry to obtain rice bran protein.
[0059] 4) Extraction: Add 50g of rice bran protein to 1000mL of water, then stir to disperse and obtain rice bran protein isolate.
[0060] 5) Enzymatic hydrolysis: Add 0.5% alkaline protease (Novozymes) according to the mass of rice bran protein isolate, at pH 9.5 and 60℃, and hydrolyze for 3 hours. Then add 0.5% neutral protease (Novozymes), at pH 8.0 and 60℃, and hydrolyze for another 3 hours. Increase the temperature to 90℃ and maintain for 20 minutes to inactivate the enzyme. Centrifuge (5000g, 10min) to obtain the supernatant of the protein hydrolysate. Decolorize with activated carbon (10%, w / vg / ml) for 24 hours. Filter using an ultrafiltration membrane with a molecular weight cutoff of 3000 Daltons, collect the permeate, and spray dry to obtain the rice bran protein hydrolysate.
[0061] 6) Column purification: The rice bran protein hydrolysate was purified using a C18 reversed-phase column (15×460mm) with gradient elution of water and ethanol aqueous solution. Specifically, the volume fraction of ethanol was gradually increased from 0% to 20% in increments of 2%. The target active peptide component eluted at a volume fraction of 12% ethanol was collected, concentrated, and then purified using a Sephadex LH-20 column (15×460mm) with elution of 12% ethanol aqueous solution. The target active peptide component eluted at a volume fraction of 12% ethanol was collected, concentrated, and dried to obtain the target immunomodulatory active octapeptide.
[0062] The immunomodulatory octapeptide obtained by this method had a yield of 30-46 g / kg and a purity of 90%.
Claims
1. An immunomodulatory active octapeptide with the following amino acid sequence: Val-Val-Pro-Arg-Phe-His-Pro-Met.
2. The use of the immunomodulatory octapeptide according to claim 1 in the preparation of immunomodulatory drugs, foods or health products.
3. The application according to claim 2, characterized in that, The drug contains pharmaceutically usable excipients.
4. The application according to claim 2, characterized in that, The drug can be formulated into various available dosage forms, such as powder, injection, suspension, etc.
5. An immunomodulatory drug, food, or health product, characterized in that, It contains the immunomodulatory octapeptide as described in claim 1 as an active ingredient.
6. A method for preparing the immunomodulatory active octapeptide of claim 1, characterized in that, The immunomodulatory octapeptide is synthesized artificially or prepared by the following methods: Rice bran is dissolved in water, the pH is adjusted to 8, and the mixture is stirred to extract the protein. The protein is then fully dissolved. The mixture is first coarsely filtered through gauze to remove insoluble residues, and then the supernatant is collected by centrifugation. The pH is adjusted to 4.5 to precipitate the protein, and the precipitate is collected by centrifugation and freeze-dried to obtain rice bran protein. The rice bran protein is dispersed in water, hydrolyzed with protease, and the enzyme is inactivated by high temperature. The supernatant of the protein hydrolysate is obtained by centrifugation, separated by membrane separation, and dried to obtain rice bran protein hydrolysate. The rice bran protein hydrolysate is purified into active peptides using reverse chromatography column elution with a gradient of water and ethanol-water solutions. The target active peptide components are collected, concentrated, and purified using a Sephadex LH-20 column. After concentration and drying, the target immunomodulatory active octapeptide is obtained. Preferably, the rice bran protein is dispersed in water by adding 5-20 times its mass of rice bran protein and then stirring to disperse it.
7. The method according to claim 6, characterized in that, Red rice bran was added to distilled water at a material-to-liquid mass ratio of 1:
10. The pH was adjusted to 8.0 with 1M NaOH solution, and the mixture was stirred and extracted for 2 hours to fully dissolve the protein. The mixture was first coarsely filtered through gauze to remove insoluble residues, then centrifuged at 3000 rpm for 20 minutes. The supernatant was collected, and the pH was adjusted to 4.5 with 1M HCl to precipitate the protein. The precipitate was collected after centrifugation at 3000 rpm for 20 minutes and freeze-dried to obtain rice bran protein. The rice bran protein was dispersed in water, hydrolyzed with protease, and then the enzyme was inactivated at high temperature. The supernatant of the protein hydrolysate was obtained by centrifugation, separated by membrane separation, and dried to obtain rice bran protein hydrolysate. The rice bran protein hydrolysate was purified using reverse-phase chromatography to obtain active peptides. A gradient elution with water and ethanol was used, specifically increasing the ethanol volume fraction from 0% to 20% in increments of 2%. The target active peptide component eluted with 8% ethanol was collected, concentrated, and then purified using Sephadex. Purification was performed using an LH-20 column, followed by elution with an 8% (v / v) ethanol aqueous solution. The target active peptide fraction eluted with an 8% (v / v) ethanol concentration was collected, concentrated, and dried to obtain the target immunomodulatory active octapeptide.
8. The method according to claim 6, characterized in that, After hydrolysis with protease, the enzyme is inactivated by high temperature. The supernatant of the protein hydrolysate is obtained by centrifugation, membrane separation, and drying. To obtain rice bran protein hydrolysate, 0.2%-2% alkaline protease is added according to the mass of rice bran protein, at pH 7.0-10.0 and temperature 35-65℃ for 1-5 hours. Then, 0.2%-2% alkaline protease is added, at pH 7.0-10.0 and temperature 35-65℃ for 1-5 hours. Then, 0.2%-2% neutral protease is added, at pH 7.0-9.0 and temperature 45-65℃ for 1-5 hours. The temperature is raised to 90℃ and held for 20 minutes to inactivate the enzyme. The supernatant of the protein hydrolysate is obtained by centrifugation, decolorized with activated carbon, filtered using an ultrafiltration membrane with a molecular weight cutoff of 3000 Daltons, and the permeate is collected and spray-dried to obtain rice bran protein hydrolysate.
9. The method according to claim 7, characterized in that, After adding protease for hydrolysis, the enzyme is inactivated by high temperature. The supernatant of the protein hydrolysate is obtained by centrifugation, separated by membrane separation, and dried to obtain rice bran protein hydrolysate. The process involves adding 0.5% alkaline protease according to the mass of the isolated rice bran protein, at pH 9.5 and temperature 65℃, for 3 hours of enzymatic hydrolysis. Then, 0.5% neutral protease is added, at pH 8.0 and temperature 60℃, for 3 hours of enzymatic hydrolysis. The temperature is then raised to 90℃ and maintained for 20 minutes to inactivate the enzyme. The supernatant of the protein hydrolysate is obtained by centrifugation at 5000g for 10 minutes. The supernatant is decolorized with activated carbon, filtered using an ultrafiltration membrane with a molecular weight cutoff of 3000 Daltons, and the permeate is collected and spray-dried to obtain the rice bran protein hydrolysate.
10. The use of rice bran in the preparation of the immunomodulatory active octapeptide according to claim 1.