A supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols

Abstract

The present invention belongs to the technical field of agricultural product extraction, and specifically relates to a supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols. The present invention improves the solubility of supercritical carbon dioxide on apple polyphenols through a composite carrier, ultrasonic assisted treatment and microwave assisted treatment, first uses modified pseudo-boehmite for a first purification treatment, and then cooperates with amino activated carbon for a second purification treatment, so as to synergistically improve the purity of apple polyphenols.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural product extraction, and in particular relates to a supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols. Background Art

[0002] Apple polyphenols are plant active substances in apples. Their structure is mainly composed of a combination of benzene rings and polyhydroxyl groups. Types include anthocyanins, flavan-3-ols, hydroxybenzoic acids, flavonols, and dihydrochalcone. Existing studies have shown that apple polyphenols have anti-cancer, antioxidant, and lipid-lowering functions in the human body. In the food field, apple polyphenols are also used as food preservatives to preserve meat products. Supercritical fluid refers to a fluid at a critical point, a special state between gas and liquid. Carbon dioxide is often used as a solvent due to its stable properties, non-toxicity, and easy separation. Supercritical carbon dioxide fluid extraction technology uses carbon dioxide as a solvent to change the critical pressure or critical temperature of carbon dioxide in a supercritical state, thereby extracting bioactive substances from the extract.

[0003] A Chinese patent (publication number CN111228351A) discloses a method for extracting polyphenols from apple pomace. The invention uses a specific concentration of sodium hydroxide and a specific protective agent to hydrolyze the apple pomace, which can significantly increase the release of bound phenols, extract free phenols and bound phenols at the same time, and improve the extraction efficiency. The total phenols extracted have good antioxidant activity, and the preparation method is simple, the yield is high, and the application range is wide. It is of great significance to promote the comprehensive utilization of apple processing waste, increase product added value, and promote the sustainable development of the industry. However, the patent does not use supercritical carbon dioxide for extraction, nor does it solve the problem of low purity of apple polyphenol extraction.

[0004] Therefore, how to use supercritical carbon dioxide extraction method to extract apple polyphenols and purify apple polyphenols to effectively improve the purity of apple polyphenol extraction has become a direction that needs to be focused on. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols, aiming to solve the problem of low purity of apple polyphenols extracted when using supercritical carbon dioxide for extraction in the prior art.

[0006] The present invention improves the dissolution capacity of supercritical carbon dioxide on apple polyphenols through composite carrying agent, ultrasonic assisted treatment and microwave assisted treatment, performs a first purification treatment in combination with modified pseudo-boehmite, and performs a second purification treatment in combination with amino activated carbon, thereby synergistically improving the purity of apple polyphenols.

[0007] The technical solution of the present invention is as follows:

[0008] The present invention provides a supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols, comprising the following steps:

[0009] Step S1: by weight, 80-100 parts of apple pomace are crushed into 40-60 meshes, then added into 100-120 parts of a composite carrier and stirred for 40-60 minutes, and then subjected to ultrasonic-assisted treatment and microwave-assisted treatment in sequence to obtain an apple pomace slurry;

[0010] Step S2: adding 80 to 100 portions of the apple pomace slurry into a supercritical fluid extraction tank, first filling it with supercritical carbon dioxide, and then performing extraction treatment to obtain a mixture;

[0011] Step S3: after the extraction treatment is completed, the mixture is transferred to a separation kettle for separation treatment to obtain an apple polyphenol extract and a residue;

[0012] Step S4: the apple polyphenol extract is first subjected to a first purification treatment using pseudo-boehmite, then subjected to a second purification treatment using activated carbon, and finally evaporated, concentrated, and dried to obtain purified apple polyphenol.

[0013] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0014] As a preferred technical solution of the present invention, the composite carrying agent is ethanol and methanol; the mass ratio of the ethanol and methanol is (1-3):1.

[0015] As a preferred technical solution of the present invention, the conditions of the ultrasonic assisted treatment include: ultrasonic power of 380-400W, treatment temperature of 56-60°C, and treatment time of 40-60min.

[0016] As a preferred technical solution of the present invention, the conditions of the microwave-assisted treatment include: microwave power of 660 to 700 W, and microwave time of 2 to 4 minutes.

[0017] The composite carrier has a strong affinity with the extracted apple polyphenols, and can significantly improve the subsequent supercritical carbon dioxide's ability to dissolve apple polyphenols; the ultrasonic-assisted treatment process will produce cavitation effects, mechanical effects, thermal effects, etc. The combination of multi-level effects will produce high shear forces, generate microjets, accelerate the breakage of apple cell walls, enhance solvent penetration, improve mass transfer efficiency, and shorten extraction time; the high-frequency electromagnetic waves of microwave-assisted treatment can directly act on the extract cell system, and polar substances such as water molecules contained in the cells quickly absorb microwave energy and generate a large amount of heat. The cells rupture or break due to internal heat expansion, which accelerates the penetration of the extraction solvent. The combined effect improves the subsequent apple polyphenol extraction efficiency.

[0018] Preferably, the operation of charging supercritical carbon dioxide includes: injecting supercritical carbon dioxide fluid at a temperature of 50-60°C, a pressure of 2.6-2.8MPa, and a carbon dioxide flow rate of 500-700L / h, and maintaining the carbon dioxide flow for 18-24min.

[0019] Preferably, the conditions of the extraction treatment include: extractor temperature of 54-58° C., extraction pressure of 30-34 MPa, and extraction time of 120-150 min.

[0020] As a preferred technical solution of the present invention, the pseudo-boehmite is modified pseudo-boehmite; the preparation method of the modified pseudo-boehmite comprises: adding 4 to 5 parts of diammonium hydrogen phosphate to 20 to 30 parts of deionized water by weight, stirring and dissolving to obtain a diammonium hydrogen phosphate aqueous solution; adding 20 to 30 parts of pseudo-boehmite to 80 to 100 parts of deionized water, stirring for 0.5 to 0.8 hours to obtain a pseudo-boehmite aqueous solution, then dripping the diammonium hydrogen phosphate aqueous solution and stirring for 1 to 2 hours, then dripping a nitric acid aqueous solution with a mass concentration of 20 to 30% to adjust the pH to 5 to 6, stirring for 6 to 8 hours, standing at room temperature for 15 to 20 hours, then heat treating at 110 to 120° C. for 2 to 3 hours, and cooling to room temperature to obtain modified pseudo-boehmite.

[0021] As a preferred technical solution of the present invention, the pseudo-boehmite particle size D 50 The particle size is 10-30 μm, and the specific surface area is 300-400 m 2 / g.

[0022] As a material with high specific surface area and rich pore structure, modified pseudo-boehmite shows excellent performance in the field of adsorption. By introducing phosphate for modification, the acidity of the pseudo-boehmite surface is enhanced, thereby improving the adsorption capacity of the composite carrier, reducing impurities and improving the purity of the final product.

[0023] As a preferred technical solution of the present invention, the activated carbon is amino activated carbon; the preparation method of the amino activated carbon comprises: adding 3 to 5 parts of activated carbon to 16 to 20 parts of nitric acid solution with a mass concentration of 10%, reacting at 70 to 75°C for 4 to 6 hours, filtering the product, washing, and drying to obtain the amino activated carbon.

[0024] As a preferred technical solution of the present invention, the average particle size of the activated carbon is 50 to 100 meshes.

[0025] Amination activated carbon introduces amino groups, which are polar functional groups. On the one hand, they can combine with polar impurities through hydrogen bonds or dipole-dipole interactions. On the other hand, they can also adsorb negatively charged impurities through electrostatic attraction, effectively reducing impurities and improving the purity of apple polyphenols.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention firstly breaks the structure of apple pomace by using a composite carrier, ultrasonic-assisted treatment and microwave-assisted treatment, thereby improving the dissolution capacity of apple polyphenols by subsequent supercritical carbon dioxide; then, a first purification treatment is performed in combination with modified pseudo-boehmite, and the acidity of the pseudo-boehmite surface is enhanced by introducing phosphate, thereby improving the adsorption capacity of the composite carrier; finally, a second purification treatment is performed in combination with amino-activated carbon, and the adsorption capacity of impurities is enhanced by the active group amino group, thereby synergistically improving the purity of apple polyphenols.

[0028] (2) The composite carrier of the present invention has a strong affinity with the apple polyphenols to be extracted, and can significantly improve the subsequent supercritical carbon dioxide's ability to dissolve apple polyphenols; the ultrasonic-assisted treatment process will produce cavitation effects, mechanical effects, thermal effects, etc., and the combination of multiple effects will produce high shear forces, generate microjets, accelerate the rate of apple cell wall breakage, enhance solvent penetration, improve mass transfer efficiency, and shorten extraction time; the high-frequency electromagnetic waves of microwave-assisted treatment can directly act on the extract cell system, and polar substances such as water molecules contained in the cells quickly absorb microwave energy and generate a large amount of heat. The cells rupture or break due to internal heat expansion, which accelerates the penetration of the extraction solvent. The combined effect improves the subsequent apple polyphenol extraction efficiency.

[0029] (3) The present invention uses modified pseudo-boehmite for the first purification treatment. As a material with a high specific surface area and rich pore structure, modified pseudo-boehmite exhibits excellent performance in the field of adsorption. By introducing phosphate for modification, the acidity of the pseudo-boehmite surface is enhanced, thereby improving the adsorption capacity of the composite carrier, reducing impurities, and improving the purity of the final product.

[0030] (4) The present invention uses amino activated carbon for the second purification treatment. Aminated activated carbon introduces amino groups. Amino groups are polar functional groups. On the one hand, they can combine with polar impurities through hydrogen bonds or dipole-dipole interactions. On the other hand, they can also adsorb negatively charged impurities through electrostatic attraction, thereby effectively reducing impurities and improving the purity of apple polyphenols. DETAILED DESCRIPTION

[0031] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0032] The sources of some components in the embodiments and comparative examples are as follows:

[0033] Apple pomace, purchased from Shaanxi Xianyang Aguo Anna Juice Co., Ltd.;

[0034] Ethanol, CAS No. 64-17-5, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0035] Methanol, CAS No. 67-56-1, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0036] Pseudo-boehmite Ⅰ, model YY-12, particle size D 50 The surface area is 12 μm and the specific surface area is 385 m 2 / g, purchased from Harbin Yinyi Technology Co., Ltd.;

[0037] Pseudo-boehmite II, model YY-13, particle size D 50 The surface area is 5 μm and the specific surface area is 505 m 2 / g, purchased from Harbin Yinyi Technology Co., Ltd.;

[0038] Pseudo-boehmite III, model YY-SB, particle size D 50 The surface area is 50 μm and the specific surface area is 265 m 2 / g, purchased from Harbin Yinyi Technology Co., Ltd.;

[0039] Diammonium hydrogen phosphate, CAS No. 7783-28-0, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0040] Nitric acid, CAS7697-37-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0041] Activated carbon I, product number C299105, average particle size 100 mesh, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0042] Activated carbon II, product number A768977, average particle size 200 mesh, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0043] Activated carbon III, product number A805342, average particle size 12 mesh, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0044] Preparation of modified pseudo-boehmite: by weight, 5 parts of diammonium hydrogen phosphate were added to 30 parts of deionized water, stirred and dissolved to obtain a diammonium hydrogen phosphate aqueous solution; 30 parts of pseudo-boehmite I (particle size D 50 The surface area is 12 μm and the specific surface area is 385 m 2 / g) was added into 100 parts of deionized water, stirred for 0.8h to obtain a pseudo-boehmite aqueous solution, then the diammonium hydrogen phosphate aqueous solution was added dropwise and stirred for 2h, then a 30% mass concentration of nitric acid aqueous solution was added dropwise to adjust the pH to 6, stirred for 8h, allowed to stand at room temperature for 20h, then heat treated at 120°C for 2h, and cooled to room temperature to obtain modified pseudo-boehmite.

[0045] Preparation of aminated activated carbon: By weight, add 5 parts of activated carbon I (average particle size is 100 mesh) to 20 parts of 10% nitric acid solution, react at 75°C for 4 hours, filter the product, wash and dry to obtain aminated activated carbon.

[0046] Example 1

[0047] This embodiment provides a supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols, comprising the following steps:

[0048] Step S1: by weight, 100 parts of apple pomace are crushed into 60 meshes, then added into 120 parts of a composite carrier (90 parts of ethanol and 30 parts of methanol), stirred for 60 minutes, and then subjected to ultrasonic assisted treatment (ultrasonic power of 400 W, treatment temperature of 60° C., treatment time of 40 minutes) and microwave assisted treatment (microwave power of 700 W, microwave time of 2 minutes) in sequence to obtain an apple pomace slurry;

[0049] Step S2: adding 100 portions of the apple pomace slurry into a supercritical fluid extraction tank, first filling it with supercritical carbon dioxide (under the conditions of temperature of 60° C., pressure of 2.8 MPa, carbon dioxide flow rate of 700 L / h, injecting supercritical carbon dioxide fluid, and keeping the carbon dioxide flowing for 18 min), and then performing extraction treatment (extractor temperature of 58° C., extraction pressure of 34 MPa, extraction time of 120 min), to obtain a mixture;

[0050] Step S3: after the extraction treatment is completed, the mixture is transferred to a separation kettle for separation treatment to obtain an apple polyphenol extract and a residue;

[0051] Step S4: the apple polyphenol extract is first subjected to a first purification treatment using modified pseudo-boehmite, then subjected to a second purification treatment using amino-activated carbon, and finally evaporated, concentrated, and dried to obtain purified apple polyphenol.

[0052] Example 2

[0053] This embodiment provides a supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols, comprising the following steps:

[0054] Step S1: by weight, 80 parts of apple pomace are crushed into 40 meshes, then added into 100 parts of a composite carrier (50 parts of ethanol and 50 parts of methanol) and stirred for 40 minutes, and then subjected to ultrasonic assisted treatment (ultrasonic power of 380 W, treatment temperature of 56° C., treatment time of 40 minutes) and microwave assisted treatment (microwave power of 660 W, microwave time of 4 minutes) in sequence to obtain an apple pomace slurry;

[0055] Step S2: adding 80 parts of the apple pomace slurry into a supercritical fluid extraction tank, first filling it with supercritical carbon dioxide (under the conditions of temperature of 50° C., pressure of 2.6 MPa, carbon dioxide flow rate of 500 L / h, injecting supercritical carbon dioxide fluid, and keeping the carbon dioxide flowing for 24 minutes), and then performing extraction treatment (extractor temperature of 54° C., extraction pressure of 30 MPa, extraction time of 150 minutes), to obtain a mixture;

[0056] Step S3: after the extraction treatment is completed, the mixture is transferred to a separation kettle for separation treatment to obtain an apple polyphenol extract and a residue;

[0057] Step S4: the apple polyphenol extract is first subjected to a first purification treatment using modified pseudo-boehmite, then subjected to a second purification treatment using amino-activated carbon, and finally evaporated, concentrated, and dried to obtain purified apple polyphenol.

[0058] Example 3

[0059] This embodiment provides a supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols, comprising the following steps:

[0060] Step S1: by weight, 90 parts of apple pomace are crushed into 50 meshes, then added into 110 parts of a composite carrier (60 parts of ethanol and 50 parts of methanol) and stirred for 50 minutes, and then subjected to ultrasonic assisted treatment (ultrasonic power of 390 W, treatment temperature of 58° C., treatment time of 50 minutes) and microwave assisted treatment (microwave power of 680 W, microwave time of 3 minutes) in sequence to obtain an apple pomace slurry;

[0061] Step S2: adding 90 parts of the apple pomace slurry into a supercritical fluid extraction tank, first filling it with supercritical carbon dioxide (under the conditions of temperature of 55° C., pressure of 2.7 MPa, carbon dioxide flow rate of 600 L / h, injecting supercritical carbon dioxide fluid, and keeping the carbon dioxide flowing for 22 minutes), and then performing extraction treatment (extractor temperature of 56° C., extraction pressure of 32 MPa, extraction time of 140 minutes), to obtain a mixture;

[0062] Step S3: after the extraction treatment is completed, the mixture is transferred to a separation kettle for separation treatment to obtain an apple polyphenol extract and a residue;

[0063] Step S4: the apple polyphenol extract is first subjected to a first purification treatment using modified pseudo-boehmite, then subjected to a second purification treatment using amino-activated carbon, and finally evaporated, concentrated, and dried to obtain purified apple polyphenol.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 1 is that in step S1, the amount of ethanol in the composite carrying agent is changed to 30 parts, and the amount of methanol is changed to 90 parts.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 1 is that in step S1, the amount of ethanol in the composite carrying agent is changed to 100 parts, and the amount of methanol is changed to 20 parts.

[0068] Comparative Example 3

[0069] The difference between this comparative example and Example 1 is that no ultrasonic auxiliary treatment is performed in step S1.

[0070] Comparative Example 4

[0071] The difference between this comparative example and Example 1 is that microwave-assisted treatment is not performed in step S1.

[0072] Comparative Example 5

[0073] The difference between this comparative example and Example 1 is that in step S4, pseudo-boehmite I is used instead of modified pseudo-boehmite to perform the first purification treatment.

[0074] Comparative Example 6

[0075] The difference between this comparative example and Example 1 is that in step S4, pseudo-boehmite II is used instead of pseudo-boehmite I to prepare modified pseudo-boehmite.

[0076] Comparative Example 7

[0077] The difference between this comparative example and Example 1 is that in step S4, pseudo-boehmite III is used instead of pseudo-boehmite I to prepare modified pseudo-boehmite.

[0078] Comparative Example 8

[0079] The difference between this comparative example and Example 1 is that in step S4, activated carbon I is used instead of aminated activated carbon for the second purification treatment.

[0080] Comparative Example 9

[0081] The difference between this comparative example and Example 1 is that in step S4, activated carbon II is used instead of activated carbon I to prepare the amination activated carbon.

[0082] Comparative Example 10

[0083] The difference between this comparative example and Example 1 is that in step S4, activated carbon III is used instead of activated carbon I to prepare the amination activated carbon.

[0084] The purity of the apple polyphenols extracted by the methods provided in the above embodiments and comparative examples was tested, and the testing method was as follows: high performance liquid chromatography was used, the chromatographic column used was Apollo-C18 (250×4.6 mm, 5 μm), the column temperature was 30° C., the mobile phase was methanol: water = 72:28, the flow rate was 1 mL / min, and the injection volume was 20 μL; sample solution was prepared, 2 mg of the apple polyphenols of the embodiments and comparative examples were weighed, and each was diluted to 10 mL with the mobile phase for testing.

[0085] The above performance test data is shown in Table 1.

[0086] Table 1 Performance test results

[0087] Apple polyphenol purity (%) Example 1 99.3 Example 2 99.1 Example 3 99.2 Comparative Example 1 94.7 Comparative Example 2 95.1 Comparative Example 3 96.3 Comparative Example 4 95.8 Comparative Example 5 91.4 Comparative Example 6 91.9 Comparative Example 7 92.2 Comparative Example 8 90.1 Comparative Example 9 90.7 Comparative Example 10 91.3

[0088] From the above content, it can be seen that the purity of apple polyphenols extracted by the technical solution of the present invention is 99.1-99.3% (Examples 1-3); compared with Example 1, step S1 changes the amount of ethanol in the composite carrier to 30 parts and the amount of methanol to 90 parts. Due to the small amount of ethanol, the composite carrier is not effective, the extraction effect is reduced, and the purity of apple polyphenols is reduced (Comparative Example 1); compared with Example 1, step S1 changes the amount of ethanol in the composite carrier to 100 parts and the amount of methanol to 20 parts. Due to the excessive amount of ethanol, the composite carrier is not effective. Compared with Example 1, the ultrasonic-assisted treatment was not performed in step S1, and the purity of apple polyphenols was reduced (Comparative Example 3); Compared with Example 1, the microwave-assisted treatment was not performed in step S1, and the purity of apple polyphenols was reduced (Comparative Example 4); Compared with Example 1, pseudo-boehmite I was used in step S4 instead of modified pseudo-boehmite for the first purification treatment, and the purity of apple polyphenols was reduced (Comparative Example 5); Compared with Example 1, pseudo-boehmite II was used in step S4 instead of pseudo-boehmite I for the first purification treatment. In the preparation of modified pseudo-boehmite, due to the small particle size of pseudo-boehmite II and the large specific surface area, the modification effect is not good, the purification effect is poor, and the purity of apple polyphenols is reduced (Comparative Example 6); compared with Example 1, in step S4, pseudo-boehmite III is used to replace pseudo-boehmite I to prepare modified pseudo-boehmite. Due to the large particle size of pseudo-boehmite II and the small specific surface area, the modification effect is not good, the purification effect is poor, and the purity of apple polyphenols is reduced (Comparative Example 7); compared with Example 1, activated carbon I is used to replace amino activated carbon in step S4. The second purification treatment was performed, and the purity of apple polyphenols decreased (Comparative Example 8); compared with Example 1, activated carbon II was used instead of activated carbon I in step S4 to prepare amino activated carbon. Since the mesh number of activated carbon II was too large, the modification effect was not good, and the purification effect was worse, so the purity of apple polyphenols decreased (Comparative Example 9); compared with Example 1, activated carbon III was used instead of activated carbon I in step S4 to prepare amino activated carbon. Since the mesh number of activated carbon III was too small, the modification effect was not good, and the purification effect was worse, so the purity of apple polyphenols decreased (Comparative Example 10).

[0089] In summary, the present invention improves the solubility of supercritical carbon dioxide on apple polyphenols through a composite carrier, ultrasonic-assisted treatment and microwave-assisted treatment, first uses modified pseudo-boehmite for the first purification treatment, and then uses amino-activated carbon for the second purification treatment, thereby synergistically improving the purity of apple polyphenols.

[0090] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols, characterized in that: The following steps are involved: Step S1: by weight, 80-100 parts of apple pomace are crushed into 40-60 meshes, then added into 100-120 parts of a composite carrier and stirred for 40-60 minutes, and then subjected to ultrasonic-assisted treatment and microwave-assisted treatment in sequence to obtain an apple pomace slurry; Step S2: adding 80 to 100 portions of the apple pomace slurry into a supercritical fluid extraction tank, first filling it with supercritical carbon dioxide, and then performing extraction treatment to obtain a mixture; Step S3: after the extraction treatment is completed, the mixture is transferred to a separation kettle for separation treatment to obtain an apple polyphenol extract and a residue; Step S4: the apple polyphenol extract is first subjected to a first purification treatment using pseudo-boehmite, then subjected to a second purification treatment using activated carbon, and finally evaporated, concentrated, and dried to obtain purified apple polyphenol.

2. The supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols according to claim 1, characterized in that: The composite carrier is ethanol and methanol; the mass ratio of ethanol to methanol is (1-3):

1.

3. The supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols according to claim 1, characterized in that: The conditions of the ultrasonic-assisted treatment include: ultrasonic power of 380-400W, treatment temperature of 56-60°C, and treatment time of 40-60min.

4. The supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols according to claim 1, characterized in that: The conditions of the microwave-assisted treatment include: microwave power of 660-700 W and microwave time of 2-4 min.

5. The supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols according to claim 1, characterized in that: The operation of charging supercritical carbon dioxide includes: injecting supercritical carbon dioxide fluid under the conditions of temperature of 50-60°C, pressure of 2.6-2.8MPa, and carbon dioxide flow rate of 500-700L / h, and keeping the carbon dioxide flowing for 18-24min.

6. The supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols according to claim 1, characterized in that: The extraction treatment conditions include: extractor temperature of 54-58° C., extraction pressure of 30-34 MPa, and extraction time of 120-150 min.

7. The supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols according to claim 1, characterized in that: The pseudo-boehmite is modified pseudo-boehmite; The preparation method of modified pseudo-boehmite comprises: adding 4 to 5 parts of diammonium hydrogen phosphate to 20 to 30 parts of deionized water by weight, stirring and dissolving to obtain a diammonium hydrogen phosphate aqueous solution; adding 20 to 30 parts of pseudo-boehmite to 80 to 100 parts of deionized water, stirring for 0.5 to 0.8 hours to obtain a pseudo-boehmite aqueous solution, then dripping the diammonium hydrogen phosphate aqueous solution and stirring for 1 to 2 hours, then dripping a nitric acid aqueous solution with a mass concentration of 20 to 30% to adjust the pH to 5 to 6, stirring for 6 to 8 hours, standing at room temperature for 15 to 20 hours, then heat treating at 110 to 120° C. for 2 to 3 hours, and cooling to room temperature to obtain modified pseudo-boehmite.

8. The supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols according to claim 1, characterized in that: The pseudo-boehmite particle size D 50 The particle size is 10-30 μm, and the specific surface area is 300-400 m 2 / g.

9. The supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols according to claim 1, characterized in that: The activated carbon is amino activated carbon; The preparation method of the aminated activated carbon comprises: adding 3 to 5 parts of activated carbon to 16 to 20 parts of nitric acid solution with a mass concentration of 10% by weight, reacting at 70 to 75° C. for 4 to 6 hours, filtering the product, washing, and drying to obtain the aminated activated carbon.

10. The supercritical carbon dioxide extraction method for efficiently extracting apple polyphenols according to claim 1, characterized in that: The average particle size of the activated carbon is 50 to 100 meshes.