A method for enriching polyphenols in rice bran by multi-channel trapping combined cycle adsorption

Abstract

The application discloses a method for enriching polyphenols in rice bran by a multi-channel interception combined circulation adsorption, and comprises the following steps: (1) raw material pretreatment; (2) ultrasonic-assisted organic solvent crude extraction; (3) multi-channel interception combined circulation adsorption treatment; (4) solvent elution; and (5) vacuum concentration. The method takes rice bran as a raw material, enriches polyphenols in the rice bran by a multi-channel interception combined circulation adsorption, and optimizes enrichment conditions of the polyphenols, so that the prepared rice bran polyphenols have high total phenol content, total flavonoid content and in-vitro antioxidant activity, and the method has the advantages of simple operation, high extraction efficiency and reduced solvent consumption. The method can not only improve the utilization value of the rice bran, but also promote the upgrading of the rice industry and reduce waste.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plant secondary metabolite extraction and separation, and particularly relates to a method for enriching polyphenols in rice bran through multi-channel interception combined circulation adsorption. BACKGROUND

[0002] Rice bran is a by-product formed during the rice processing process, accounting for about 6% to 10% of the total amount of brown rice. The content of phenolic substances in rice bran accounts for more than 50% of the total amount of phenolic substances in whole brown rice. These phenolic substances have multiple activities such as anti-inflammatory, antioxidant, and antibacterial. At present, the processing amount of rice bran in China accounts for only 10% to 20%, and the deep processing and high-value utilization thereof are in the initial stage. Most of the rice bran is used as animal feed or treated as garbage, causing serious resource waste and environmental pollution. At present, the separation and purification means of rice bran polyphenols mainly focus on adsorption resin purification technology, high-speed counter-current chromatography separation and purification technology, etc. However, due to the large number of types of rice bran polyphenols and the large difference in molecular structure and polarity, a single means cannot meet the requirements of efficient separation. At present, there are still problems such as low efficiency, limited selectivity, and low purity in the separation and purification process. SUMMARY

[0003] The present application provides a method for enriching polyphenols in rice bran through multi-channel interception combined circulation adsorption, in order to solve the problem of waste of a large amount of by-products during the rice processing process and the environmental pollution caused thereby, and the continuous understanding of the nutritional value of whole grain raw materials, and to solve the practical problems of low extraction efficiency and low purity of plant polyphenols.

[0004] The present application adopts the following technical solutions:

[0005] A method for enriching polyphenols in rice bran through multi-channel interception combined circulation adsorption, comprising the following steps:

[0006] (1) Raw material pretreatment: crushing and sieving the rice bran to obtain rice bran powder; defatting the rice bran powder with n-hexane to obtain defatted rice bran powder; drying the defatted rice bran powder for standby use;

[0007] (2) Ultrasonic-assisted organic solvent crude extraction: mixing the defatted rice bran powder obtained in step (1) with an ethanol solution and performing ultrasonic treatment, and then centrifuging to obtain a rice bran polyphenol crude extract;

[0008] (3) Multi-channel interception combined cycle adsorption treatment: the rice bran polyphenol extract is injected into a multi-channel interception device, the same volume of rice bran polyphenol extract is injected into each interception channel, the rice bran polyphenol extract is uniformly passed through the interception channel to intercept macromolecular impurities, the preliminary separation is completed, the rice bran preliminary separation polyphenol extract is obtained, the rice bran preliminary separation polyphenol extract is directly injected into the corresponding pretreated solid phase extraction column of the cycle adsorber, the solid phase extraction column adsorption loading rate is 30%~50%, then the multi-channel peristaltic pump is started to perform cycle adsorption, when the volume of the effluent in the effluent collection bottle at the outlet of each solid phase extraction column is 1 / 2~2 / 3 of the volume of the rice bran polyphenol extract injected into the corresponding interception channel, the cycle adsorption is stopped, and the effluent is discarded;

[0009] The multi-channel interception device is composed of a plurality of needle filters in parallel, the cycle adsorber includes a solid phase extraction device and a multi-channel peristaltic pump, the solid phase extraction device is provided with solid phase extraction columns matched with the number of interception channels of the multi-channel interception device, and the number of hoses connected to the multi-channel peristaltic pump is matched with the number of solid phase extraction columns;

[0010] When the multi-channel interception treatment is performed, the outlets of the interception channels of the multi-channel interception device in parallel are respectively connected to the inlets of the corresponding solid phase extraction columns; when the cycle adsorption treatment is performed, the inlets of the hoses of the multi-channel peristaltic pump are respectively connected to the effluent collection bottles at the outlets of the corresponding solid phase extraction columns, and the outlets of the hoses of the multi-channel peristaltic pump are respectively connected to the inlets of the corresponding solid phase extraction columns.

[0011] (4) Solvent elution: each solid phase extraction column is used to elute the adsorbed rice bran polyphenol under negative pressure with methanol, and the eluted rice bran polyphenol is collected.

[0012] (5) Reduced pressure concentration: the eluted rice bran polyphenol is concentrated under reduced pressure to obtain rice bran polyphenol.

[0013] Further, in step (1), the rice bran is crushed and sieved through a 80-100 mesh sieve to obtain rice bran powder.

[0014] Further, in step (1), the rice bran powder is defatted by n-hexane as follows: the rice bran powder and n-hexane are mixed according to a solid-liquid ratio of 1g:8-12mL, stirred at room temperature at 500-700rpm for 1-3h for defatting treatment, centrifuged, and the supernatant is removed; the above operation is repeated 2-3 times to obtain defatted rice bran powder; the defatted rice bran powder is dried at 40-50℃ for 10-16h and is ready for use.

[0015] Further, in step (2), the defatted rice bran powder and 50v / v%-70v / v% ethanol solution are mixed in a solid-liquid ratio of 1g:10-30mL for ultrasonic treatment, the ultrasonic power is 450-550W, the ultrasonic temperature is 35-45°C, and the ultrasonic time is 25-35min, and after ultrasonic treatment, centrifugation is performed to obtain an extract and a residue; the extract is stored at 4-10°C for later use, and the residue is repeatedly extracted 2-3 times according to the above operation, and the 3-4 times of extract are combined to obtain a crude rice bran polyphenol extract.

[0016] Further, in step (3), the parallel multi-channel interception device is a parallel six-channel interception device or a parallel seven-channel interception device or a parallel eight-channel interception device.

[0017] Further, in step (3), the filter membrane pore size of the needle filter is 0.45μm.

[0018] Further, in step (3), the solid-phase extraction column pretreatment is that the solid-phase extraction column is first activated with acetonitrile under the condition of-0.05--0.07MPa, and then balanced with PBS under the condition of-0.05--0.07MPa.

[0019] Further, in step (3), the flow rate of the multi-channel peristaltic pump is 0.75-1.5mL / min.

[0020] Further, in step (4), each solid-phase extraction column is eluted with 2 / 3-3 / 2 volumes of methanol corresponding to the rice bran polyphenol crude extract injected into the interception channel under the condition of-0.05--0.07MPa to elute the adsorbed rice bran polyphenol.

[0021] Further, in step (5), the eluted rice bran polyphenol is concentrated under reduced pressure to 10%-20% of the original volume under the condition of 40-50°C and-0.08Mpa--0.098Mpa to obtain rice bran polyphenol.

[0022] The beneficial effects of the present application are:

[0023] 1、The present application uses rice bran as raw material, and the polyphenols in the rice bran are enriched by multi-channel interception combined circulation adsorption, and the enrichment conditions are optimized, and the prepared rice bran polyphenol has high total phenol content, total flavonoid content and in vitro antioxidant activity, and the operation is simple, the extraction efficiency is high, and the solvent consumption is reduced.

[0024] 2, The multi-channel interception device of the present application is adopted by a plurality of needle filters in parallel, according to the molecular weight difference of polyphenols and impurities, through interception to remove impurities, and to enrich the target polyphenol components. The multi-channel design can make the crude extraction solution of rice bran polyphenols pass through multiple parallel interception channels at the same time, increase the effective filtration area, improve the permeation flux, reduce the interception membrane pollution, and the operation consistency is high. The circulating adsorber includes a solid phase extraction device and a multi-channel peristaltic pump, the solid phase extraction device is provided with a solid phase extraction column matched with the number of interception channels of the multi-channel interception device (i.e. six), and the number of hoses connected to the multi-channel peristaltic pump is matched with the number of solid phase extraction columns (i.e. six). The solid phase extraction column of the circulating adsorber is based on the characteristics of the adsorption carrier, and through external pressure regulation (multi-channel peristaltic pump), the cyclic adsorption and elution of rice bran polyphenols are realized. The hydrophobic polyphenol molecules in the preliminary separation polyphenol extract of rice bran after multi-channel interception treatment are combined on the adsorbent by hydrophobic interaction with the adsorption carrier filled in the solid phase extraction column of the circulating adsorber, while the impurities and other non-target substances have no strong affinity with the adsorption carrier, and directly flow out from the outlet of the solid phase extraction column of the circulating adsorber, under the action of external pressure, so that they flow back to the solid phase extraction column of the circulating adsorber at the inlet of the solid phase extraction column of the circulating adsorber for cyclic adsorption. This cyclic adsorption operation can maximize the adsorption capacity of the adsorption carrier and improve the adsorption efficiency. Compared with the traditional means, the multi-channel interception combined with cyclic adsorption for separating and enriching rice bran polyphenols can efficiently remove impurities, improve extraction efficiency, save solvent, and realize higher purity and more effective enrichment of polyphenols in the extraction product. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The multi-channel interception combined with cyclic adsorption processing schematic diagram of the present application.

[0026] 1 is an interception channel, 2 is a solid phase extraction column, 3 is a flow-out liquid collection bottle, and 4 is a multi-channel peristaltic pump. DETAILED DESCRIPTION

[0027] The present application will be further described below in conjunction with specific examples and drawings, but the present application is not limited by the examples.

[0028] In the following examples and comparative examples, the parallel six-channel interception device is composed of six parallel needle filters (BKMAMLAB, PES material, 25mmx0.45um); the circulating adsorber includes a solid phase extraction device (Labshark) and a multi-channel peristaltic pump (Baoding Rongbai constant flow pump manufacturing Co., Ltd., BT100-2J), the solid phase extraction device is provided with a solid phase extraction column (BKMAMLAB, C18 column, 12mL) matched with the number of interception channels of the six-channel interception device (i.e. six), and the number of hoses connected to the multi-channel peristaltic pump is matched with the number of solid phase extraction columns (i.e. six).

[0029] Example 1

[0030] Step one, raw material pretreatment: rice bran powder was obtained by crushing the rice bran produced in the rice processing process and passing through an 80-mesh sieve; the rice bran powder and n-hexane were mixed according to a solid-liquid ratio of 1:10 (g:mL), stirred at room temperature at 600 rpm for 2 h for defatting treatment, centrifuged at 6000 rpm for 20 min, the supernatant was removed, and the above operation (i.e., mixing with n-hexane-stirring-centrifugation-removing the supernatant) was repeated 3 times to obtain defatted rice bran powder; the defatted rice bran powder was dried in an oven at 40°C for 12 h and then stored for use.

[0031] Step two, ultrasonic-assisted organic solvent crude extraction: the defatted rice bran powder and 60 v / v% ethanol solution were poured into a beaker according to a solid-liquid ratio of 1:20 (g:mL), and the beaker was placed in an ultrasonic cleaner for ultrasonic treatment, with an ultrasonic power of 500 W, an ultrasonic temperature of 40°C, and an ultrasonic time of 30 min; after ultrasonic treatment, centrifugation was performed at 3000 rpm for 25 min to obtain an extract and a residue, the extract was stored at 4°C for use, and the residue was extracted again according to the above operation (i.e., mixing with 60 v / v% ethanol solution-ultrasonic treatment-centrifugation-extract storage for use) for 2 more times; the extract from the three times was combined to obtain a crude rice bran polyphenol extract.

[0032] Step three, multi-channel interception combined with circulation adsorption treatment: the crude rice bran polyphenol extract was injected into six parallel interception devices, 35 mL of the crude rice bran polyphenol extract was injected into each interception channel, the crude rice bran polyphenol extract passed through the interception channel at a constant speed to intercept macromolecular impurities, and preliminary separation was completed to obtain a rice bran preliminary separation polyphenol extract; the rice bran preliminary separation polyphenol extract was directly injected into the corresponding pre-treated solid phase extraction column (the solid phase extraction column adsorption loading rate was 30%) of the circulation adsorber, and then a multi-channel peristaltic pump was started for circulation adsorption, the flow rate of the multi-channel peristaltic pump was 1 mL / min, when the effluent in the effluent collection bottle at the outlet of each solid phase extraction column was about 20 mL, the circulation adsorption was stopped, and the effluent was discarded; wherein, as shown in the figure, during the multi-channel interception treatment, the outlets of the six parallel interception channels 1 were connected to the inlets of the corresponding solid phase extraction columns 2; during the circulation adsorption treatment, the inlets of the soft tubes of the multi-channel peristaltic pump 4 were connected to the effluent collection bottles 3 at the outlets of the corresponding solid phase extraction columns 2, and the outlets of the soft tubes of the multi-channel peristaltic pump 4 were connected to the inlets of the corresponding solid phase extraction columns 2; the solid phase extraction column pretreatment was that each solid phase extraction column was first activated with 15 mL of acetonitrile at -0.06 MPa, and then balanced with 15 mL of PBS (0.01 mM, pH 7.4) at -0.06 MPa. Figure 1

[0033] ​Step four: solvent elution: each solid phase extraction column was eluted with 30 mL of methanol at -0.06 MPa to elute the adsorbed rice bran polyphenols, and the eluted rice bran polyphenols were collected.

[0034] Step five: reduced pressure concentration: the eluted rice bran polyphenols were concentrated to 15% of the original volume under reduced pressure in a rotary evaporator at 40 °C and -0.098 MPa to obtain rice bran polyphenols.

[0035] Example 2

[0036] In this example, the solid phase extraction column had an adsorbed loading rate of 35%, and the other conditions were the same as in Example 1.

[0037] Example 3

[0038] In this example, the solid phase extraction column had an adsorbed loading rate of 40%, and the other conditions were the same as in Example 1.

[0039] Example 4

[0040] In this example, the solid phase extraction column had an adsorbed loading rate of 45%, and the other conditions were the same as in Example 1.

[0041] Example 5

[0042] In this example, the solid phase extraction column had an adsorbed loading rate of 50%, and the other conditions were the same as in Example 1.

[0043] Comparative Example 1

[0044] Step one: pretreatment of raw materials: rice bran produced during the processing of rice was ground and passed through an 80-mesh sieve to obtain rice bran powder; the rice bran powder and n-hexane were mixed according to a solid-liquid ratio of 1:10 (g:mL) and stirred at room temperature at 600 rpm for 2 h for defatting treatment, and then centrifuged at 6000 rpm for 20 min to remove the supernatant. The above operation (i.e., mixing with n-hexane, stirring, centrifugation, and removing the supernatant) was repeated three times to obtain defatted rice bran powder; the defatted rice bran powder was dried in an oven at 40 °C for 12 h and then stored for use.

[0045] Step two: ultrasonic-assisted organic solvent extraction: the defatted rice bran powder and 60 v / v% ethanol solution were mixed according to a solid-liquid ratio of 1:20 (g:mL) in a beaker, and the beaker was placed in an ultrasonic cleaner for ultrasonic treatment at an ultrasonic power of 500 W and an ultrasonic temperature of 40 °C for 30 min. After ultrasonic treatment, the mixture was centrifuged at 3000 rpm for 25 min to obtain an extract and a residue. The extract was stored at 4 °C for use, and the residue was subjected to the above operation (i.e., mixing with 60 v / v% ethanol solution, ultrasonic treatment, centrifugation, and storing the extract for use) for two more times of extraction. The three extracts were combined to obtain a crude rice bran polyphenol extract.

[0046] Step three, multi-channel interception combined adsorption treatment: inject the crude extraction of rice bran polyphenols into the parallel six-channel interception device, inject 35 mL of crude extraction of rice bran polyphenols into each interception channel, and uniformly pass the crude extraction of rice bran polyphenols through the interception channel to intercept macromolecular impurities, complete the preliminary separation, and obtain the preliminary separation of rice bran polyphenol extract. The preliminary separation of rice bran polyphenol extract is directly injected into the corresponding pretreated solid phase extraction column (the solid phase extraction column adsorption loading rate is 40%) of the circulating adsorber, adsorbed under the condition of -0.06 MPa, and the effluent in the effluent collection bottle at the outlet of each solid phase extraction column is discarded. During the multi-channel interception treatment, the outlets of the six parallel interception channels are connected to the inlets of the corresponding solid phase extraction columns. The pretreatment of the solid phase extraction column is that each solid phase extraction column is first activated with 15 mL of acetonitrile under the condition of -0.06 MPa, and then balanced with 15 mL of PBS (0.01 mM, pH 7.4) under the condition of -0.06 MPa.

[0047] Step four, solvent elution: each solid phase extraction column is eluted with 30 mL of methanol under the condition of -0.06 MPa to elute the adsorbed rice bran polyphenols, and the eluted rice bran polyphenols are collected.

[0048] Step five, vacuum concentration: the eluted rice bran polyphenols are vacuum concentrated in a rotary evaporator under the condition of 40°C, -0.098 MPa to 15% of the original volume, and the rice bran polyphenols are obtained.

[0049] Comparative example 2

[0050] Step one, raw material pretreatment: the rice bran produced in the rice processing process is crushed and passed through an 80-mesh sieve to obtain rice bran powder; the rice bran powder and n-hexane are mixed according to the solid-liquid ratio of 1:10 (g:mL) for defatting treatment at room temperature and 600 rpm for 2 h, centrifuged at 6000 rpm for 20 min, the supernatant is removed, and the above operation (i.e. mixing with n-hexane, stirring, centrifugation, and removing the supernatant) is repeated 3 times to obtain defatted rice bran powder; the defatted rice bran powder is placed in a 40°C oven for drying for 12 h and is ready for use.

[0051] Step two, ultrasonic-assisted organic solvent crude extraction: the defatted rice bran powder and 60 v / v% ethanol solution are poured into a beaker according to the solid-liquid ratio of 1:20 (g:mL), and the beaker is placed in an ultrasonic cleaner for ultrasonic treatment. The ultrasonic power is 500 W, the ultrasonic temperature is 40°C, and the ultrasonic time is 30 min. After ultrasonic treatment, centrifuge at 3000 rpm for 25 min to obtain the extract and residue. The extract is stored at 4°C for use, and the residue is extracted again according to the above operation (i.e. mixing with 60 v / v% ethanol solution, ultrasonic treatment, centrifugation, and storing the extract for use) for 2 times. The three times of extraction are combined to obtain the crude extraction of rice bran polyphenols.

[0052] Step three, circulating adsorption treatment: the crude extract of rice bran polyphenols is injected into the pretreated solid phase extraction column of the circulating adsorption device, 35 mL of crude extract of rice bran polyphenols is injected into each solid phase extraction column, and the circulating adsorption is started by starting the multi-channel peristaltic pump with a flow rate of 1 mL / min. When the effluent in the effluent collection bottle at the outlet of each solid phase extraction column is about 20 mL, stop the circulating adsorption, and discard the effluent; wherein, during the circulating adsorption treatment, the inlets of the soft tubes of the multi-channel peristaltic pump are connected with the effluent collection bottles at the outlets of the corresponding solid phase extraction columns, and the outlets of the soft tubes of the multi-channel peristaltic pump are connected with the inlets of the corresponding solid phase extraction columns; the pretreatment of the solid phase extraction column is that each solid phase extraction column is first activated with 15 mL of acetonitrile under the condition of-0.06 MPa, and then balanced with 15 mL of PBS (0.01 mM, pH 7.4) under the condition of-0.06 MPa.

[0053] Step four, solvent elution: each solid phase extraction column is eluted with 30 mL of methanol under the condition of-0.06 MPa to elute the adsorbed rice bran polyphenols, and the eluted rice bran polyphenols are collected.

[0054] Step five, vacuum concentration: the eluted rice bran polyphenols are vacuum concentrated in a rotary evaporator under the condition of 40°C and-0.098 MPa to 15% of the original volume to obtain rice bran polyphenols.

[0055] The total phenol content, total flavonoid content, total antioxidant capacity (FRAP), DPPH radical scavenging capacity, and ABTS radical scavenging capacity of the rice bran polyphenols prepared in each example and comparative example are determined, and each index is determined according to the literature (Fractionation of phenolic compounds from hickory by-products using solid-phase extraction-sonication: Chemical composition, antioxidant and antimicrobial activity [J]. Food Chemistry, 2024, 460: 140633.).

[0056]

[0057] As shown in the above table, it is found by comparing examples 1-5 and comparative examples 1-2 that the multi-channel interception combined cycle adsorption enrichment of rice bran polyphenols can effectively improve the total phenol content, total flavonoid content and in vitro antioxidant capacity of rice bran polyphenols, and it has the best total phenol content, total flavonoid content, total antioxidant capacity, DPPH free radical scavenging capacity and ABTS free radical scavenging capacity, which are: 352±5.8mg GAE / g DW, 142±2.6mg RE / g DW, 73.8±0.60mmol Fe 2+ / g DW, 5.16±0.15μg / mL(IC50), 2.11±0.03μg / mL(IC50). The physicochemical indexes of rice bran polyphenols treated by multi-channel interception combined adsorption or only cycle adsorption are not good.

[0058] In summary, the present application uses rice bran as raw material, and is treated by multi-channel interception combined cycle adsorption enrichment technology, and the enrichment conditions are optimized, and the prepared rice bran polyphenols have high total phenol content, total flavonoid content and in vitro antioxidant activity, and the operation is simple, the extraction efficiency is high, and the solvent consumption is reduced. The present application not only can improve the utilization value of rice bran, but also can promote the upgrading of rice industry and reduce waste.

[0059] Although the present application has been disclosed as above with preferred embodiments, it is not intended to limit the present application, and anyone skilled in the art can make various modifications and modifications without departing from the spirit and scope of the present application, therefore the protection scope of the present application should be defined by the claims.

Claims

1. A method for the multi-channel cut-off combined cycle adsorption enrichment of polyphenols in rice bran, characterized by, The method comprises the following steps: (1) raw material pretreatment: crushing and sieving the rice bran to obtain rice bran powder; defatting the rice bran powder with n-hexane to obtain defatted rice bran powder; drying the defatted rice bran powder for later use; (2) ultrasonic-assisted organic solvent crude extraction: mixing the defatted rice bran powder obtained in step (1) with an ethanol solution and performing ultrasonic treatment, and then centrifuging to obtain a rice bran polyphenol crude extract; (3) multi-channel interception combined cycle adsorption treatment: injecting the rice bran polyphenol extract into a parallel multi-channel interception device, injecting the same volume of rice bran polyphenol crude extract into each interception channel, and uniformly passing the rice bran polyphenol crude extract through the interception channels to intercept macromolecular impurities, thereby completing preliminary separation to obtain a rice bran preliminary separation polyphenol extract; directly injecting the rice bran preliminary separation polyphenol extract into a corresponding pretreated solid-phase extraction column of a cycle adsorber, setting the solid-phase extraction column adsorption loading rate to 30%-50%, starting a multi-channel peristaltic pump to perform cycle adsorption, and when the volume of the effluent in the effluent collection bottle at the outlet of each solid-phase extraction column is 1 / 2-2 / 3 of the volume of the rice bran polyphenol crude extract injected into the corresponding interception channel, stopping the cycle adsorption and discarding the effluent; The parallel multi-channel interception device is composed of a plurality of parallel needle filters, the cycle adsorber comprises a solid-phase extraction device and a multi-channel peristaltic pump, the solid-phase extraction device is provided with solid-phase extraction columns matching the number of interception channels of the multi-channel interception device, and the number of hoses connected to the multi-channel peristaltic pump matches the number of solid-phase extraction columns; During the multi-channel interception treatment, the outlets of the interception channels of the parallel multi-channel interception device are respectively connected to the inlets of the corresponding solid-phase extraction columns; during the cycle adsorption treatment, the inlets of the hoses of the multi-channel peristaltic pump are respectively connected to the effluent collection bottles at the outlets of the corresponding solid-phase extraction columns, and the outlets of the hoses of the multi-channel peristaltic pump are respectively connected to the inlets of the corresponding solid-phase extraction columns; (4) solvent elution: eluting the adsorbed rice bran polyphenols from each solid-phase extraction column under negative pressure with methanol, and collecting the eluted rice bran polyphenols; (5) reduced-pressure concentration: reducing the pressure to concentrate the eluted rice bran polyphenols, thereby obtaining rice bran polyphenols.

2. The method of claim 1, wherein the method is a multi-channel cut-off combined cycle adsorption enrichment of polyphenols in rice bran, characterized by, In step (1), the rice bran is crushed and sieved through an 80-100-mesh sieve to obtain the rice bran powder.

3. The method of claim 1, wherein the method is a multi-channel cut-off combined cycle adsorption enrichment of polyphenols in rice bran, characterized by, In step (1), the defatting of the rice bran powder with n-hexane is performed as follows: mixing the rice bran powder with n-hexane at a material-liquid ratio of 1 g:8-12 mL, stirring at room temperature and at 500-700 rpm for 1-3 h for defatting treatment, centrifuging to remove the supernatant, repeating the above operation 2-3 times, and drying the defatted rice bran powder at 40-50 °C for 10-16 h for later use.

4. The method of claim 1, wherein the multi-channel trapping combined cycle adsorption enrichment of polyphenols in rice bran is characterized by, In step (2), the defatted rice bran powder and 50v / v%-70v / v% ethanol solution are mixed according to the solid-liquid ratio of 1g:10-30mL for ultrasonic treatment, the ultrasonic power is 450-550W, the ultrasonic temperature is 35-45°C, and the ultrasonic time is 25-35min, and after ultrasonic treatment, centrifugation is performed to obtain an extract and a residue; the extract is stored at 4-10°C for later use, and the residue is repeatedly extracted 2-3 times according to the above operation, and 3-4 times of the extract are combined to obtain a crude rice bran polyphenol extract.

5. The method of claim 1, wherein the method is a multi-channel cut-off combined cycle adsorption enrichment of polyphenols in rice bran. In step (3), the parallel multi-channel interception device is a parallel six-channel interception device or a parallel seven-channel interception device or a parallel eight-channel interception device.

6. The method of claim 1, wherein the method is a multi-channel trapping combined cycle adsorptive enrichment of polyphenols in rice bran. In step (3), the filter membrane pore size of the needle filter is 0.45μm.

7. The method of claim 1, wherein the method is a multi-channel trapping combined cycle adsorptive enrichment of polyphenols in rice bran. In step (3), the solid-phase extraction column pretreatment is that the solid-phase extraction column is first activated with acetonitrile under the condition of-0.05--0.07MPa, and then balanced with PBS under the condition of-0.05--0.07MPa.

8. The method of claim 1, wherein the method is a multi-channel trapping combined cycle adsorptive enrichment of polyphenols in rice bran. In step (3), the flow rate of the multi-channel peristaltic pump is 0.75-1.5mL / min.

9. The method of claim 1, wherein the method is a multi-channel trapping combined cycle adsorptive enrichment of polyphenols in rice bran. In step (4), 2 / 3-3 / 2 volumes of methanol corresponding to the rice bran polyphenol crude extract injected into each solid-phase extraction column are used to elute the adsorbed rice bran polyphenols under the condition of-0.05--0.07MPa.

10. The method of claim 1, wherein the method is a multi-channel trapping combined cycle adsorptive enrichment of polyphenols in rice bran. In step (5), the eluted rice bran polyphenols are concentrated to 10%-20% of the original volume under the condition of 40-50°C, -0.08Mpa--0.098Mpa, to obtain rice bran polyphenols.

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