Method for efficiently removing polycyclic aromatic hydrocarbon from propolis and increasing flavone content at same time

Abstract

The invention discloses a method for efficiently removing polycyclic aromatic hydrocarbon in propolis and simultaneously increasing flavone content, which comprises the following steps: (1) crushing and crushing propolis blocks to obtain a propolis raw material; (2) filling the propolis raw material into an extraction kettle and sealing; (3) heating and pressurizing to enable the carbon dioxide and the n-hexane to form a carbon dioxide-n-hexane supercritical mixture; (4) extracting polycyclic aromatic hydrocarbon in the propolis raw material in a supercritical state; (5) after the extraction is completed, decompressing and cooling the system to recover the supercritical carbon dioxide to a gaseous state; condensing the n-hexane into liquid containing polycyclic aromatic hydrocarbon; (6) separating and recovering n-hexane; and (7) carrying out vacuum drying on the propolis extract in the extraction kettle to obtain the propolis product with reduced polycyclic aromatic hydrocarbon content. According to the invention, a supercritical CO2 extraction method is adopted, and n-hexane is used as an entrainer, so that not only is the residue of PAHs in propolis effectively reduced, but also the solvent can be recycled, the product quality is improved, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of natural product active ingredient technology, specifically to a method for efficiently removing polycyclic aromatic hydrocarbons from propolis while increasing flavonoid content. Background Technology

[0002] Propolis is a resinous substance collected by bees from the buds and bark of resin-producing plants, mixed with secretions from their hypopharyngeal and wax glands, and synthesized through repeated metabolism. It is a reddish-brown to greenish-brown powder or resinous lumps with a fragrant aroma. When heated, a waxy substance separates out; it is dispersible in water and also acts as a surfactant.

[0003] Propolis extract is a yellowish-brown or dark brown sticky substance secreted by the Chinese honeybee or the Italian honeybee, belonging to the genus Apis of the family Apidae. Its main components include flavonoids and terpenoids, and it has antibacterial, anti-inflammatory, antiviral, and immune-enhancing effects.

[0004] Polycyclic aromatic hydrocarbons (PAHs) are aromatic hydrocarbons containing two or more benzene rings. They mainly exist in two configurations: non-fused rings, including biphenyls, polyphenylene oxides, and polyphenylene aliphatic hydrocarbons; and fused rings, where two carbon atoms are shared by two benzene rings. Due to their toxicity, genotoxicity, mutagenicity, and carcinogenicity, PAHs can cause various health hazards, and the food industry strictly limits their content in food products. The PAHs in propolis are not produced by bees themselves, but rather originate entirely from environmental pollution and improper collection and processing.

[0005] Removing PAHs from propolis is a technical challenge due to the complex composition of propolis and the tight binding of PAHs to the propolis matrix. Traditional methods for reducing PAHs include activated carbon adsorption and molecular distillation. However, these methods suffer from drawbacks such as loss of bioactive substances, poor removal efficiency, high requirements for equipment configuration, and stringent process requirements. Summary of the Invention

[0006] The technical problem to be solved by this invention is to overcome the technical defects of the prior art and provide a method for efficiently removing polycyclic aromatic hydrocarbons (PAHs) from propolis while increasing the flavonoid content. Based on the principle of "like dissolves like," this invention employs supercritical CO2 extraction with n-hexane as an entrainer. This not only effectively reduces PAH residues in propolis but also allows for solvent recycling, thus improving product quality and reducing production costs. This invention meets the requirements of green processes and is suitable for industrial production.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: A method for efficiently removing polycyclic aromatic hydrocarbons from propolis while increasing flavonoid content, comprising the following steps:

[0008] (1) Raw material pretreatment: The propolis blocks are crushed and pulverized to obtain propolis raw materials;

[0009] (2) Loading: Load the pulverized propolis raw material from step (1) into the extraction vessel and seal it;

[0010] (3) Establishing a supercritical environment: heating and pressurizing the extraction vessel to make carbon dioxide reach a supercritical state and form a carbon dioxide-n-hexane supercritical mixture with n-hexane;

[0011] (4) Extraction: Under supercritical conditions, the carbon dioxide-n-hexane supercritical mixture is used to extract polycyclic aromatic hydrocarbons from the propolis raw material;

[0012] (5) Separation and collection: After extraction, the system is depressurized and cooled to restore the supercritical carbon dioxide to the gaseous state and separate the carbon dioxide by vaporization; n-hexane is condensed into a liquid containing polycyclic aromatic hydrocarbons and the liquid is collected.

[0013] (6) Solvent recovery: The liquid separated in step (5) is concentrated to separate and recover n-hexane;

[0014] (7) Product acquisition: Take out the propolis extract after the treatment in steps (5) and (6) from the extraction vessel, and vacuum dry the propolis extract to obtain a propolis product with reduced polycyclic aromatic hydrocarbon content.

[0015] Preferably, in step (1), the propolis block is placed in a crusher and crushed into small pieces of 1-2 cm. Then, the propolis small pieces are pulverized and passed through a 10-mesh sieve to obtain the propolis raw material.

[0016] Preferably, in step (4), the specific extraction conditions are: extraction pressure 35±5 MPa, extraction temperature 40±5℃, mass ratio of n-hexane to supercritical CO2 of (0.2-0.5):1; and extraction time of 8h.

[0017] Preferably, in step (4), the mass ratio of n-hexane to supercritical CO2 is 0.5:1.

[0018] Preferably, in step (5), supercritical carbon dioxide is restored to a gaseous state by means of decompression and cooling: the decompression refers to the pressure being reduced to 0 MPa; the cooling refers to the temperature being reduced to 20 ± 5 °C.

[0019] Preferably, in step (6), the liquid separated in step (5) is dried at -(0.07~0.09)MPa and 65~75℃ to collect and concentrate the liquid and recover n-hexane.

[0020] Preferably, in step (7), the vacuum drying conditions are -(0.08~0.09)MPa and 40~45℃.

[0021] Preferably, in step (1), the flavonoid content of the propolis raw material is 15.35%.

[0022] In this invention, "%" refers to mass percentage.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] (1) The present invention uses supercritical CO2 extraction and n-hexane as an entrainer, which can effectively reduce the residue of PAHs in propolis and improve the removal rate of polycyclic aromatic hydrocarbons; moreover, the solvent used can be recycled, which not only improves the product quality but also reduces the production cost.

[0025] (2) This invention achieves high recovery rate of propolis while efficiently removing polycyclic aromatic hydrocarbons (PAHs) and retaining the effective flavonoids in propolis to the maximum extent. The propolis solid obtained after treatment by the method of this invention has the following characteristics: extremely low PAH residue, only 3.0ppb-3.5ppb; high propolis recovery rate; and effectively improves the purity of flavonoids in propolis, with its content significantly increasing from 15.35% in the raw material to 27.95%.

[0026] (3) The process of this invention is carried out at low temperature, and the separation process uses pressure control rather than high temperature evaporation to separate the solute and solvent, which provides a mild processing environment for the active substances in propolis and effectively prevents oxidation caused by high temperature.

[0027] (4) This invention not only meets the requirements of green process, but is also suitable for industrial production. Detailed Implementation

[0028] To better understand the content of this invention, further description is provided below with reference to specific embodiments. It should be understood that these embodiments are only for further illustration of the invention and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the description of this invention, those skilled in the art may make some non-essential modifications or adjustments to the invention, which still fall within the protection scope of this invention.

[0029] Example 1:

[0030] 1. Propolis block crushing: Place the propolis (flavonoid content 15.35%) block in a crusher and crush it into small pieces of propolis 1-2cm to facilitate subsequent dissolution; then crush the small pieces of propolis and pass them through a 10-mesh sieve to obtain the propolis raw material.

[0031] 2. Loading: Load 200g of the crushed propolis raw material into the extraction vessel and seal it;

[0032] 3. Heating and pressurizing: The extraction vessel is heated by a heating system, and the extraction vessel is pressurized by a compressor to make the carbon dioxide reach a supercritical state.

[0033] 4. Extraction: PAHs in propolis were extracted under supercritical conditions using a mixture of carbon dioxide and n-hexane. Specific conditions were: extraction pressure 37 MPa, extraction temperature 42℃, mass ratio of n-hexane to supercritical CO2 0.2:1, and extraction time 8 h.

[0034] 5. Separation: After extraction, the supercritical carbon dioxide is restored to a gaseous state by reducing pressure (from 37 MPa to 0 MPa) and cooling to 20°C, thereby separating the extract from the solvent. The separated solvent contains PAHs.

[0035] 6. Solvent recovery: The separated extract is dried at -(0.07~0.09)MPa and 65~75℃, collected and concentrated to recover n-hexane.

[0036] 7. Vacuum drying: The extracted propolis extract was vacuum dried at -(0.08~0.09) MPa and 40~45℃ to obtain propolis blocks. The propolis recovery rate was 71.4%, the PAHs removal rate was 95.15%, and the residue was 3.5 ppb.

[0037]

[0038] Example 2:

[0039] 1. Propolis block crushing: Propolis (flavonoid content 15.35%) blocks are placed in a crusher and crushed into small pieces of 1-2cm to facilitate subsequent dissolution; then the small pieces of propolis are pulverized and passed through a 10-mesh sieve to obtain propolis raw material.

[0040] 2. Loading: Load 200g of the crushed propolis raw material into the extraction vessel and seal it.

[0041] 3. Heating and pressurizing: The extraction vessel is heated by a heating system, and the extraction vessel is pressurized by a compressor to make the carbon dioxide reach a supercritical state.

[0042] 4. Extraction: PAHs in propolis were extracted under supercritical conditions using a mixture of carbon dioxide and n-hexane. Specific conditions were: extraction pressure 35 MPa, extraction temperature 40℃, mass ratio of n-hexane to supercritical CO2 0.30:1, and extraction time 8 h.

[0043] 5. Separation: After extraction, the supercritical carbon dioxide is restored to a gaseous state by reducing pressure (from 35 MPa to 0 MPa) and cooling to 25°C, thereby separating the extract from the solvent. The separated solvent contains PAHs.

[0044] 6. Solvent recovery: The separated extract is dried at -(0.07~0.09)MPa and 65~75℃, collected and concentrated to recover n-hexane.

[0045] 7. Vacuum drying: The extracted propolis extract was vacuum dried at -(0.08~0.09) MPa and 40~45℃ to obtain propolis blocks. The propolis recovery rate was 66.7%, the PAHs removal rate was 95.57%, and the residue was 3.2 ppb.

[0046]

[0047] Example 3:

[0048] 1. Propolis block crushing: Place 200.0g of propolis (flavonoid content 15.35%) blocks in a crusher and crush them into small pieces of propolis 1-2cm to facilitate subsequent dissolution; then pulverize the small pieces of propolis and pass them through a 10-mesh sieve to obtain propolis raw material.

[0049] 2. Loading: Load 200g of the crushed propolis raw material into the extraction vessel and seal it.

[0050] 3. Heating and pressurizing: The extraction vessel is heated by a heating system, and the extraction vessel is pressurized by a compressor to make the carbon dioxide reach a supercritical state.

[0051] 4. Extraction: PAHs in propolis were extracted under supercritical conditions using a mixture of carbon dioxide and n-hexane. Specific conditions were: extraction pressure 40 MPa, extraction temperature 45℃, mass ratio of n-hexane to supercritical CO2 0.5:1, and extraction time 8 h.

[0052] 5. Separation: After extraction, the supercritical carbon dioxide is restored to a gaseous state by reducing pressure (from 40 MPa to 0 MPa) and cooling to 25°C, thereby separating the extract from the solvent. The separated solvent contains PAHs.

[0053] 6. Solvent recovery: The separated extract is dried at -(0.07~0.09)MPa and 65~75℃, collected and concentrated to recover n-hexane.

[0054] 7. Vacuum drying: The extracted propolis extract was vacuum dried at -(0.08~0.09) MPa and 40~45℃ to obtain propolis blocks. The propolis recovery rate was 53.56%, the PAHs removal rate was 95.84%, and the residue was 3.0 ppb.

[0055]

[0056] Comparative Example 1

[0057] Compared with implementation 3, the only difference is that in step (3), the mass ratio of n-hexane to critical CO2 is 0.6:1, and the removal rate of PHAs in the prepared propolis extract is 69.32%, with a residual amount of 50.01 ppb.

[0058]

[0059] Comparative Example 2

[0060] Compared with implementation 3, the only difference is that in step (4), the extraction pressure is 45 MPa, the removal rate of PHAs in the prepared propolis extract is 80.71%, and the residual amount is 13.92 ppb.

[0061]

[0062] Comparative Example 3

[0063] Compared with implementation 3, the only difference is that in step (5), the extraction temperature is 50°C, the removal rate of PHAs in the prepared propolis extract is 90.45%, and the residual amount is 6.89 ppb.

[0064]

[0065] In the above embodiments and comparative examples, the PAHs detection method was performed in accordance with GB5009.265-2021.

[0066] The foregoing description is not intended to limit the invention, nor is the invention limited to the examples given. Any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the invention should also be considered within the protection scope of the invention.

Claims

1. A method for efficiently removing polycyclic aromatic hydrocarbons from propolis while simultaneously increasing flavonoid content, characterized in that, Includes the following steps: (1) Raw material pretreatment: The propolis blocks are crushed and pulverized to obtain propolis raw materials; (2) Loading: Load the pulverized propolis raw material from step (1) into the extraction vessel and seal it; (3) Establishing a supercritical environment: heating and pressurizing the extraction vessel to make carbon dioxide reach a supercritical state and form a carbon dioxide-n-hexane supercritical mixture with n-hexane; (4) Extraction: Under supercritical conditions, the carbon dioxide-n-hexane supercritical mixture is used to extract polycyclic aromatic hydrocarbons from the propolis raw material; (5) Separation and collection: After extraction, the system is depressurized and cooled to restore the supercritical carbon dioxide to the gaseous state and separate the carbon dioxide by vaporization; n-hexane is condensed into a liquid containing polycyclic aromatic hydrocarbons and the liquid is collected. (6) Solvent recovery: The liquid separated in step (5) is concentrated to separate and recover n-hexane; (7) Product acquisition: Take out the propolis extract after the treatment in steps (5) and (6) from the extraction vessel, and vacuum dry the propolis extract to obtain a propolis product with reduced polycyclic aromatic hydrocarbon content.

2. The method for efficiently removing polycyclic aromatic hydrocarbons and increasing flavonoid content in propolis according to claim 1, characterized in that, In step (1), the propolis block is placed in a crusher and crushed into small pieces of 1-2 cm. Then the small pieces of propolis are pulverized and passed through a 10-mesh sieve to obtain the propolis raw material.

3. The method for efficiently removing polycyclic aromatic hydrocarbons and increasing flavonoid content in propolis according to claim 1, characterized in that, In step (4), the specific extraction conditions are as follows: extraction pressure 35±5 MPa, extraction temperature 40±5℃, mass ratio of n-hexane to supercritical CO2 of (0.2-0.5):1; extraction time of 8h.

4. The method for efficiently removing polycyclic aromatic hydrocarbons and increasing flavonoid content in propolis according to claim 3, characterized in that, In step (4), the mass ratio of n-hexane to supercritical CO2 is 0.5:

1.

5. The method for efficiently removing polycyclic aromatic hydrocarbons and simultaneously increasing flavonoid content in propolis according to claim 1, characterized in that, In step (5), supercritical carbon dioxide is restored to a gaseous state by reducing pressure and cooling: the pressure is reduced to 0 MPa; the temperature is reduced to 20 ± 5 °C.

6. The method for efficiently removing polycyclic aromatic hydrocarbons and increasing flavonoid content in propolis according to claim 1, characterized in that, In step (6), the liquid separated in step (5) is dried at -(0.07~0.09)MPa and 65~75℃ to collect and concentrate the liquid and recover n-hexane.

7. The method for efficiently removing polycyclic aromatic hydrocarbons and simultaneously increasing flavonoid content in propolis according to claim 1, characterized in that, In step (7), the vacuum drying conditions are -(0.08~0.09)MPa and 40~45℃.

8. The method for efficiently removing polycyclic aromatic hydrocarbons and increasing flavonoid content in propolis according to claim 1, characterized in that, In step (1), the flavonoid content of the propolis raw material is 15.35%.

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