Method for extracting flavone component in siraitia grosvenorii leaves based on supercritical carbon dioxide

Abstract

The invention relates to a method for extracting flavone components in siraitia grosvenorii leaves based on supercritical carbon dioxide. The method comprises the following steps: compressing carbon dioxide to a supercritical state and enabling the carbon dioxide to be in full contact with siraitia grosvenorii leaf powder; controlling the carbon dioxide to extract the siraitia grosvenorii leaf powder by adjusting temperature, pressure and flow, and separating and purifying the obtained extract; separating the supercritical carbon dioxide from the extract liquor through reduced pressure evaporation, rotary evaporation or freeze drying to obtain a momordica grosvenori leaf flavone extract; according to the method, a supercritical carbon dioxide extraction technology is adopted, supercritical carbon dioxide is in full contact with siraitia grosvenorii leaf powder by controlling pressure, temperature and flow, flavonoid components are extracted, supercritical carbon dioxide is separated out through methods such as reduced pressure evaporation, rotary evaporation or freeze drying, and the siraitia grosvenorii leaf flavonoids are obtained. The method solves the problems of solvent residue, low extraction efficiency, environmental pollution and the like in the traditional solvent extraction method.

Description

Technical Field

[0001] The invention relates to the technical field of plant extract preparation, in particular to a method for extracting flavonoid components in momordica grosvenori leaves based on supercritical carbon dioxide. Background Art

[0002] As an efficient and environmentally friendly extraction method, supercritical carbon dioxide extraction technology has been widely used in the extraction process of natural products. This technology uses the special properties of supercritical carbon dioxide to effectively extract the target components at a lower temperature, while avoiding the use of traditional organic solvents, reducing environmental pollution and harm to the human body. This technology not only improves the extraction efficiency, but also ensures the quality and safety of the extract, and is widely used in food, medicine, cosmetics and other fields.

[0003] In practical applications, in order to improve the extraction rate of flavonoid components in Momordica grosvenori leaves, a variety of physical and chemical methods are usually used. For example, the traditional steam distillation method can be used, and the flavonoid components are volatilized together with the water vapor by high-temperature heating, and then collected by condensation. Another commonly used method is solvent extraction, which selects a suitable organic solvent (such as ethanol, acetone) to soak the Momordica grosvenori leaves, so that the effective ingredients are dissolved in the solvent, and then separated and purified by filtering, evaporation and other steps. In addition, there is also an ultrasonic-assisted extraction method, which enhances the mass transfer process through the cavitation effect of ultrasound and improves the extraction efficiency.

[0004] However, these traditional methods have many shortcomings in the extraction process. Steam distillation requires higher temperatures, which can easily lead to thermal degradation of flavonoid components and affect the quality of the extract. Although the solvent extraction method is simple to operate, the selection and recovery of organic solvents are relatively complicated, and residual solvents may have adverse effects on product safety and the environment. Although ultrasonic-assisted extraction can increase the extraction rate, the equipment cost is relatively high in large-scale industrial production, and long-term ultrasonic action may cause structural damage to the target components. Therefore, existing extraction methods are difficult to take into account multiple requirements such as high extraction rate, low energy consumption and environmental friendliness. Summary of the invention

[0005] The main purpose of the present invention is to provide a method for extracting flavonoid components from Momordica grosvenori leaves based on supercritical carbon dioxide.

[0006] To achieve the above object, the present invention provides a method for extracting flavonoid components from Momordica grosvenori leaves based on supercritical carbon dioxide, comprising the following steps:

[0007] Wash and remove impurities from monk fruit leaves and dry them;

[0008] Cut the dried monk fruit leaves into small pieces or crush them into coarse powder;

[0009] The monk fruit leaf powder is placed in an extraction container, and the carbon dioxide is compressed to a supercritical state using a high-pressure pump and is fully contacted with the monk fruit leaf powder;

[0010] extracting the monk fruit leaf powder by adjusting the temperature, pressure and flow rate to control the carbon dioxide, and separating and purifying the obtained extract;

[0011] The supercritical carbon dioxide is separated from the extract by reduced pressure evaporation, rotary evaporation or freeze drying to obtain the monk fruit leaf flavonoids extract.

[0012] Optionally, when controlling carbon dioxide to extract the monk fruit leaf powder, the flow rate of carbon dioxide and the amount of monk fruit leaf used satisfy the following relationship:

[0013]

[0014] Among them, F is the carbon dioxide flow rate, k is a constant, W is the amount of monk fruit leaf, d is the average particle size of the monk fruit leaf particles, P is the extraction pressure, T is the extraction temperature, t is the extraction time; α, β and γ are all empirical coefficients.

[0015] Optionally, the extraction pressure ranges from 20 to 30 MPa, the extraction temperature ranges from 30 to 35° C., and the average particle size of the monk fruit leaf particles is from 50 to 100 meshes.

[0016] Optionally, separating and purifying the obtained extract specifically includes:

[0017] adding water to the extract and mixing, separating water-soluble sugars, amino acids and polysaccharide compounds to form a water solvent layer, and removing the water solvent layer;

[0018] adding chloroform to the extract and mixing them to separate the volatile oil and terpenoid compounds to form a chloroform layer, and removing the chloroform layer;

[0019] adding ether to the extract and mixing, separating carotenoids, fatty acids, and terpenes to form an ether layer, and removing the ether layer;

[0020] Petroleum ether is added to the extract and mixed to separate lipids, oils and waxes to form a petroleum ether layer, which is then removed.

[0021] Optionally, the rotary evaporation specifically comprises the following steps:

[0022] The separated and purified extract was added into a rotary evaporation bottle;

[0023] Start the rotary evaporator and evaporate the carbon dioxide by heating the water bath or oil bath;

[0024] After evaporation is complete, what remains in the rotary evaporation bottle is the monk fruit leaf flavonoids extract.

[0025] Optionally, the reduced pressure evaporation specifically comprises the following steps:

[0026] The separated and purified extract is fed into a reduced pressure evaporation device;

[0027] Control and reduce the internal pressure and temperature of the reduced pressure evaporation equipment to evaporate carbon dioxide in a low temperature environment;

[0028] After reduced pressure evaporation, the carbon dioxide in the solvent is removed, and finally a concentrated monk fruit leaf flavonoid extract is obtained.

[0029] Optionally, freeze drying specifically comprises the following steps:

[0030] Freezing the separated and purified extract to -20°C to -80°C;

[0031] The frozen extract is transferred into a freeze-drying device, and a low-temperature, low-pressure environment is formed inside the freeze-drying device to allow carbon dioxide to sublime directly;

[0032] With the carbon dioxide removed, what remains is a concentrated monk fruit leaf flavonoid extract, usually in the form of a dry powder or solid.

[0033] Optionally, when the carbon dioxide is controlled to extract the monk fruit leaf powder by adjusting the temperature, pressure and flow rate, the temperature and pressure and the solubility of carbon dioxide in a supercritical state satisfy the following formula:

[0034]

[0035] Among them, S is the solubility, T is the temperature, P is the pressure, and A, B, and C are constants.

[0036] The invention discloses an efficient, environmentally friendly and low-cost method for extracting flavone from monk fruit leaves. The method adopts supercritical carbon dioxide extraction technology, controls pressure, temperature and flow rate, makes supercritical carbon dioxide fully contact with monk fruit leaf powder, extracts flavonoid components, separates supercritical carbon dioxide by reduced pressure evaporation, rotary evaporation or freeze drying, and finally obtains a high-purity monk fruit leaf flavonoid extract, thereby solving the problems of solvent residue, low extraction efficiency, environmental pollution and the like in traditional solvent extraction methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The present invention is a flow chart of a method for extracting flavonoid components from Momordica grosvenori leaves based on supercritical carbon dioxide. DETAILED DESCRIPTION

[0038] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. The described embodiments are only possible technical implementations of the present invention, not all possible implementations. Those skilled in the art can completely combine the embodiments of the present invention to obtain other embodiments without creative work, and these embodiments are also within the scope of protection of the present invention.

[0039] Embodiment 1

[0040] Reference Figure 1 In this embodiment, a method for extracting flavonoid components from Momordica grosvenori leaves based on supercritical carbon dioxide is provided, comprising the following steps:

[0041] Step 1: Wash, remove impurities and dry the monk fruit leaves; specifically, first select fresh and healthy monk fruit leaves, remove impurities, wash, air dry or low-temperature dry them to ensure that they are free of pollution. Wash the monk fruit leaves and dry them, or use low-temperature drying, the drying temperature is controlled below 40°C, to avoid high temperature damaging the stability of flavonoid components, and obtain the monk fruit leaf dried material.

[0042] Step 2: Cut the dried monk fruit leaves into small pieces or crush them into coarse powder; Cut the dried monk fruit leaves into small pieces or crush them into coarse powder. The ideal crushing particle size should be 50-100 meshes, which can increase the contact area between supercritical CO2 and plant materials, thereby improving the extraction efficiency.

[0043] Step 3: Put the monk fruit leaf powder into the extraction container, use a high-pressure pump to compress the carbon dioxide to a supercritical state and make it fully contact with the monk fruit leaf powder; the density and solubility of supercritical CO2 are between gas and liquid, and it has a high solubility and is suitable for dissolving fat-soluble components in plants. However, its viscosity is lower than that of liquid, which allows it to better penetrate the plant cell wall and contact with plant components. And in the supercritical state, the solubility of CO2 is greatly improved, especially when dissolving fat-soluble or non-polar substances, such as flavonoids. The solubility of CO2 can be controlled by adjusting the temperature and pressure to optimize the extraction efficiency of different components.

[0044] The density and solubility of supercritical CO2 are between those of gas and liquid, and it has a high solubility, making it suitable for dissolving fat-soluble components in plants. Supercritical CO2 is transported to the extraction tower through a pipeline and fully contacted with the monk fruit leaf powder. At this stage, carbon dioxide will dissolve the flavonoids in the leaves. Since CO2 has a strong solubility in the supercritical state, bioactive components such as flavonoids can be extracted more efficiently.

[0045] Step 4: Extract the monk fruit leaf powder by adjusting the temperature, pressure and flow rate to control the carbon dioxide, and separate and purify the obtained extract; CO2 contacts the flavonoid molecules in the plant material and releases them from the plant cells through dissolution. The process of supercritical CO2 dissolving flavonoids is mainly a physical dissolution process rather than a chemical reaction. Most flavonoids are hydrophobic compounds, and CO2 has the characteristics of a non-polar solvent in a supercritical state and can dissolve fat-soluble components. Because the chemical structure of flavonoids contains hydrophobic groups such as benzene rings, they have a strong interaction with supercritical CO2 and can therefore be effectively dissolved.

[0046] During the extraction process, supercritical CO2 enters plant tissues through its fluidity and diffusivity, dissolving flavonoids in plant cells. The high diffusivity of CO2 enables it to quickly contact plant materials and remove flavonoid molecules from plant tissues through physical adsorption and dissolution. However, the solubility of supercritical CO2 is affected by temperature and pressure. The solubility of CO2 can be controlled by adjusting temperature and pressure to optimize the extraction efficiency of flavonoids. For example, higher pressure and temperature help increase the solubility of flavonoids. Increasing temperature can increase the solubility of CO2, but too high a temperature may cause degradation of certain heat-sensitive components. Increasing pressure increases the density of CO2, thereby increasing its solubility, especially for non-polar components such as flavonoids, where higher pressure can significantly increase their solubility.

[0047] Step 5: Separate supercritical carbon dioxide from the extract by reduced pressure evaporation, rotary evaporation or freeze drying to obtain the monk fruit leaf flavonoids extract.

[0048] The method of this embodiment adopts supercritical carbon dioxide extraction technology. By controlling the pressure, temperature and flow rate, the supercritical carbon dioxide is fully contacted with the monk fruit leaf powder to extract the flavonoid components. The supercritical carbon dioxide is then separated by reduced pressure evaporation, rotary evaporation or freeze drying, and finally a high-purity monk fruit leaf flavonoid extract is obtained, which solves the problems of solvent residue, low extraction efficiency, environmental pollution, etc. in the traditional solvent extraction method.

[0049] Furthermore, when controlling carbon dioxide to extract monk fruit leaf powder, the amount of carbon dioxide usually refers to the flow rate of CO2; the amount of monk fruit leaf usually refers to the dry weight, and the relationship between the two needs to be optimized through experiments. The ratio of the two is not a fixed value, but is closely related to the extraction conditions, such as extraction temperature, extraction pressure, extraction time and solubility of the target component.

[0050] Then in this embodiment, the flow rate of carbon dioxide and the amount of Momordica grosvenori leaves satisfy the following relationship:

[0051]

[0052] Where, F is the carbon dioxide flow rate;

[0053] k is a constant, and its value depends on the specific equipment and experimental conditions;

[0054] W is the dosage of monk fruit leaf, d is the average particle size of monk fruit leaf particles, the smaller the particles, the better the mass transfer, so the flow rate is inversely proportional to the particle size;

[0055] P is the extraction pressure, α is the empirical coefficient, P α Indicates the effect of pressure on flow. Usually, the effect of pressure on flow is positively correlated, and α is usually around 1;

[0056] T is the extraction temperature, β is the empirical coefficient, T β Indicates the effect of temperature on flow rate. Since the solubility of CO2 decreases at higher temperatures, β usually takes a negative value;

[0057] t is the extraction time, γ is the empirical coefficient, t γ Represents the effect of time on flow rate. Usually, extraction time is proportional to flow rate.

[0058] It should be understood that the greater the CO2 flow rate, the higher the dissolution efficiency of the extraction. Although it can increase the extraction speed, it will also lead to an increase in the use of CO2, increase energy consumption and costs, and may lead to the extraction of certain non-target components, which may also bring higher costs and equipment burdens. When the flow rate is too low, the dissolution capacity of CO2 is not strong enough, and the target component may not be effectively extracted. Normally, the flow rate of CO2 should be kept within a reasonable range to avoid excessive use. The amount of monk fruit leaf input should also be determined based on the concentration of the target component and the desired extraction effect. The particle size of monk fruit leaves directly affects the permeability and extraction effect of CO2. Smaller particles help to improve the contact efficiency and solubility of CO2, thereby increasing the extraction rate of the target component.

[0059] In this embodiment, by adopting the above-mentioned technical solution of calculation, the relationship between the carbon dioxide flow rate and the amount of Momordica grosvenori leaf can be accurately controlled to ensure the effective contact between carbon dioxide and Momordica grosvenori leaf powder during the extraction process, thereby improving the extraction efficiency and purity of flavonoid components. At the same time, the introduction of this relationship makes the extraction process more controllable, helps to optimize process parameters, reduce energy consumption, and improve production efficiency.

[0060] Further, the extraction pressure of the present embodiment ranges from 20 to 30 MPa, the extraction temperature ranges from 30 to 35°C, and the average particle size of the Momordica leaf particles is 50 to 100 meshes. By adopting the above technical scheme, the extraction pressure ranges from 20 to 30 MPa, which can ensure that carbon dioxide is in a supercritical state, thereby improving the extraction efficiency and selectivity. At the same time, the extraction temperature ranges from 30 to 35°C, which can avoid the destruction of flavonoid components by high temperature while ensuring the extraction effect. The average particle size of the Momordica leaf particles is 50 to 100 meshes, which helps to increase the surface area, promote the effective release of flavonoid components, and further improve the extraction rate. The optimization of these parameters makes the entire extraction process more efficient and stable, and finally obtains a high-purity Momordica leaf flavonoid extract.

[0061] Furthermore, the extracted liquid in this embodiment may contain a variety of compounds, especially a complex mixture of plant materials. Separating and purifying the obtained extract specifically includes:

[0062] adding water to the extract and mixing, separating water-soluble sugars, amino acids and polysaccharide compounds to form a water solvent layer, and removing the water solvent layer;

[0063] adding chloroform to the extract and mixing them to separate the volatile oil and terpenoid compounds to form a chloroform layer, and removing the chloroform layer;

[0064] adding ether to the extract and mixing, separating carotenoids, fatty acids, and terpenes to form an ether layer, and removing the ether layer;

[0065] Petroleum ether is added to the extract and mixed to separate lipids, oils and waxes to form a petroleum ether layer, which is then removed.

[0066] By adopting the above technical scheme, high-purity flavonoid components can be effectively extracted from Momordica grosvenori leaves. First, by adding water to the extract and mixing, water-soluble sugars, amino acids and polysaccharide compounds can be effectively removed. The presence of these impurities will interfere with the subsequent purification process. Then, chloroform is added to the extract and mixed, and volatile oils and terpenoid compounds can be separated to further reduce the impact of impurities. Subsequently, ether is added to the extract and mixed, and carotenoids, fatty acids and terpenes can be separated to further improve the purity of flavonoid components. Finally, petroleum ether is added to the extract and mixed, and lipids, oils and waxes can be separated to ensure that the final Momordica grosvenori leaf flavonoid extract is pure and free of impurities. This series of separation and purification steps significantly improves the extraction efficiency and purity of flavonoid components, and is suitable for large-scale industrial production.

[0067] Furthermore, the rotary evaporation of this embodiment specifically includes the following steps: adding the separated and purified extract to a rotary evaporation bottle; starting the rotary evaporator, evaporating the carbon dioxide by heating a water bath or an oil bath; after the evaporation is completed, what remains in the rotary evaporation bottle is the Momordica leaf flavonoids extract. By adopting the above technical scheme, the supercritical carbon dioxide in the extract can be effectively removed, thereby obtaining a pure Momordica leaf flavonoids extract. Specifically, the separated and purified extract is added to a rotary evaporation bottle, and the carbon dioxide is rapidly evaporated by heating a water bath or an oil bath using a rotary evaporator, thereby ensuring the effective removal of carbon dioxide and improving the purity of the extract. After the evaporation is completed, what remains in the rotary evaporation bottle is a high-purity Momordica leaf flavonoids extract.

[0068] Furthermore, in this embodiment, when the carbon dioxide is controlled to extract the monk fruit leaf powder by adjusting the temperature, pressure and flow rate, the temperature and pressure and the solubility of carbon dioxide in a supercritical state satisfy the following formula:

[0069]

[0070] Among them, S is the solubility, T is the temperature, P is the pressure, and A, B, and C are constants.

[0071] This formula shows that solubility has a certain relationship with temperature and pressure. The appropriate combination of temperature and pressure will increase the solubility of the target component, thereby improving the extraction efficiency. By adopting the above technical solution, the solubility of supercritical carbon dioxide in the extraction process can be accurately controlled to ensure the effective extraction of the flavonoid components of monk fruit leaves. The application of this formula makes it possible to optimize the extraction conditions under different temperature and pressure conditions, improve the extraction rate and purity of the target product, and reduce energy consumption and costs.

[0072] Embodiment 2

[0073] As another embodiment of the present invention, the difference between this embodiment and embodiment one is that this embodiment adopts the method of reduced pressure evaporation, and reduced pressure evaporation specifically includes the following steps: adding the separated and purified extract to the reduced pressure evaporation equipment; controlling and reducing the internal pressure and internal temperature of the reduced pressure evaporation equipment so that carbon dioxide evaporates under low temperature environment; after reduced pressure evaporation, the carbon dioxide in the solvent is removed, and finally a concentrated Momordica leaf flavonoid extract is obtained. By adopting the above technical scheme, the carbon dioxide in the extract can be effectively removed to ensure the high purification of the Momordica leaf flavonoid extract. Specifically, by controlling the pressure and temperature inside the reduced pressure evaporation equipment, carbon dioxide can be efficiently evaporated under low temperature environment, thereby avoiding the influence of high temperature on flavonoid components and ensuring the quality and activity of the extract. After reduced pressure evaporation, the carbon dioxide in the solvent is completely removed, and finally a high-concentration, high-purity Momordica leaf flavonoid extract is obtained.

[0074] Embodiment 2

[0075] As another embodiment of the present invention, the difference between this embodiment and embodiment 1 is that this embodiment adopts a freeze drying method. Freeze drying specifically includes the following steps: freezing the separated and purified extract to -20°C to -80°C; transferring the frozen extract to a freeze drying device, controlling the freeze drying device to form a low temperature and low pressure environment, so that carbon dioxide is directly sublimated; with the removal of carbon dioxide, what remains is a concentrated Momordica leaf flavonoid extract, usually in the form of dry powder or solid. By adopting the above technical scheme, the freeze drying step can effectively remove supercritical carbon dioxide from the extract while maintaining the stability and activity of the Momordica leaf flavonoid extract. Specifically: freezing the separated and purified extract to -20°C to -80°C can effectively fix the structure of the extract, prevent chemical changes or physical damage during subsequent processing, and ensure the integrity of the flavonoid components. Transferring the frozen extract to a freeze drying device, controlling the freeze drying device to form a low temperature and low pressure environment, so that carbon dioxide is directly sublimated. This process not only avoids the destruction of flavonoid components by high temperature, but also efficiently removes solvents and retains more biologically active substances. As the carbon dioxide is removed, what remains is a concentrated extract of monk fruit leaf flavonoids, usually in the form of dry powder or solid. This form is convenient for storage and transportation, and is also convenient for further processing and application, such as the preparation of health products, medicines, etc.

[0076] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, device, article or method including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, device, article or method. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, device, article or method including the element.

[0077] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for extracting flavonoid components from Momordica grosvenori leaves based on supercritical carbon dioxide, characterized in that: The following steps are involved: Wash and remove impurities from monk fruit leaves and dry them; Cut the dried monk fruit leaves into small pieces or crush them into coarse powder; The monk fruit leaf powder is placed in an extraction container, and carbon dioxide is compressed to a supercritical state using a high-pressure pump so as to be in full contact with the monk fruit leaf powder; extracting the monk fruit leaf powder by adjusting the temperature, pressure and flow rate to control the carbon dioxide, and separating and purifying the obtained extract; The supercritical carbon dioxide is separated from the extract by reduced pressure evaporation, rotary evaporation or freeze drying to obtain the monk fruit leaf flavonoids extract.

2. The extraction method according to claim 1, characterized in that When the carbon dioxide is controlled to extract the Momordica grosvenori leaf powder, the flow rate of the carbon dioxide and the amount of the Momordica grosvenori leaf satisfy the following relationship: Among them, F is the carbon dioxide flow rate, k is a constant, W is the amount of monk fruit leaf, d is the average particle size of the monk fruit leaf particles, P is the extraction pressure, T is the extraction temperature, t is the extraction time; α, β and γ are all empirical coefficients.

3. The extraction method according to claim 2, characterized in that The extraction pressure ranges from 20 to 30 MPa, the extraction temperature ranges from 30 to 35° C., and the average particle size of the Momordica grosvenori leaf particles is from 50 to 100 meshes.

4. The extraction method according to claim 1, characterized in that The separation and purification of the obtained extract specifically includes: adding water to the extract and mixing them to separate water-soluble sugars, amino acids and polysaccharide compounds to form a water solvent layer, and removing the water solvent layer; adding chloroform to the extract and mixing them to separate volatile oil and terpenoid compounds to form a chloroform layer, and removing the chloroform layer; adding ether to the extract and mixing them to separate carotenoids, fatty acids, and terpenes to form an ether layer, and removing the ether layer; Petroleum ether is added to the extract and mixed to separate lipids, oils and waxes to form a petroleum ether layer, and the petroleum ether layer is removed.

5. The extraction method according to claim 1, characterized in that The rotary evaporation specifically comprises the following steps: The separated and purified extract was added into a rotary evaporation bottle; Start the rotary evaporator and evaporate the carbon dioxide by heating the water bath or oil bath; After evaporation is complete, what remains in the rotary evaporation bottle is the monk fruit leaf flavonoids extract.

6. The extraction method according to claim 1, characterized in that The reduced pressure evaporation specifically comprises the following steps: The separated and purified extract is fed into a reduced pressure evaporation device; Controlling and lowering the internal pressure and internal temperature of the reduced pressure evaporation device to evaporate carbon dioxide under low temperature conditions; After reduced pressure evaporation, the carbon dioxide in the solvent is removed, and finally a concentrated monk fruit leaf flavonoid extract is obtained.

7. The extraction method according to claim 1, characterized in that The freeze drying specifically comprises the following steps: Freezing the separated and purified extract to -20°C to -80°C; The frozen extract is transferred into a freeze-drying device, and a low-temperature, low-pressure environment is formed inside the freeze-drying device to allow carbon dioxide to sublime directly; With the carbon dioxide removed, what remains is a concentrated monk fruit leaf flavonoid extract, usually in the form of a dry powder or solid.

8. The extraction method according to claim 1, characterized in that When the carbon dioxide is controlled by adjusting the temperature, pressure and flow rate to extract the monk fruit leaf powder, the temperature, pressure and the solubility of carbon dioxide in the supercritical state satisfy the following formula: Among them, S is the solubility, T is the temperature, P is the pressure, and A, B, and C are constants.

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