Extraction method of natural product extract and application of natural product extract in agar extraction

Abstract

The invention discloses an extraction method of a natural product extract and application of the natural product extract in agar extraction, and the extraction method of the natural product extract comprises the following steps: S20, before obtaining the natural product extract, carrying out electron beam irradiation on a natural product. The electron beam can degrade the molecular structure of the natural product, and can enable the molecules of the extract to absorb energy to generate free radicals, so that the extraction of the extract can be efficiently completed while the cutting of the molecular chain of the extract is realized; professional closed microwave extraction equipment is not needed in the extraction process, so that the extraction cost is greatly reduced; meanwhile, electron beam irradiation is used in the extraction process, so that the extraction process is clean and sterile; and no chemical reagent or solvent is used in the extraction process, so that the pollution to the extract and the environment is avoided, and the purity of the extract can be ensured.

Description

Technical Field

[0001] This invention relates to the field of material extraction technology, specifically to a method for extracting natural extracts and its application in agar extraction. Background Technology

[0002] Currently, the commonly used extraction methods for natural extracts on the market mainly include microwave-assisted extraction, ultrasound-assisted extraction, and enzyme-assisted extraction.

[0003] Compared with traditional methods, these extraction methods (microwave-assisted extraction, ultrasound-assisted extraction, and enzyme-assisted extraction) have advantages such as shorter extraction time, lower energy consumption, and reduced chemical reagent usage. However, they still have certain limitations, such as requiring specialized equipment, higher costs, and a decrease in the quality of the extracted extract. Specifically, microwave-assisted extraction requires specialized closed-loop microwave extraction equipment, which has high maintenance costs. Microwave heating is prone to generating a "hot spot effect," and localized high temperatures can easily damage the extract structure. Furthermore, the heating efficiency depends on the dielectric constant of the material, making it poorly suited for low-moisture or dense raw materials and natural raw materials containing impurities. Ultrasonic-assisted extraction's core technology is... While the impact force generated by cavitation can disrupt the cell walls of natural materials, ultrasound has a limited range of action, uneven energy distribution in large-scale production, and the shear force and localized high temperature of high-intensity ultrasound can easily damage the extract structure (e.g., disrupting the polysaccharide chains of agar). Furthermore, the extraction process lacks sterilization, and the low-temperature environment is prone to microbial growth. Specific enzymes used to disrupt the cell walls of natural materials (such as cellulase and hemicellulase) are expensive to prepare, and their activity is sensitive to process parameters. Enzyme residues require additional purification, which increases costs and leads to extract loss. Moreover, enzyme-catalyzed reactions follow kinetic laws, are time-consuming, and are easily affected by substrate concentration and inhibitors. On the other hand, these extraction methods have low yields, requiring more natural raw materials to obtain the same amount of extract. Finally, these extraction methods lack the sterility of modern processes, increasing the risk of microbial contamination.

[0004] Therefore, it is of great significance to develop a low-cost, efficient, and pollution-free extraction method for natural extracts. Summary of the Invention

[0005] To address at least one of the aforementioned problems, according to one aspect of the present invention, a method for extracting natural extracts is provided.

[0006] The extraction method for this natural extract includes the following steps: S20: The natural substance is irradiated with an electron beam before obtaining the natural extract.

[0007] Because electron beams can degrade the molecular structure of natural products and cause the molecules of the extract to generate free radicals by absorbing energy, the extraction process can efficiently complete the extraction while simultaneously trimming the molecular chains of the extract. The extraction process does not require specialized closed-loop microwave extraction equipment, significantly reducing extraction costs. Since electron beam irradiation is used, the extraction process is kept clean and sterile. Furthermore, because no chemical reagents or solvents are used, it avoids pollution to the extract and the environment, while ensuring the purity of the extract. The extraction method proposed in this application is applicable to the extraction of various natural products, improving extraction rate and purity, and can be applied to the extraction of natural products in multiple fields such as medicine, food, and cosmetics.

[0008] In some embodiments, step S10, which involves soaking the natural material, is included before step S20. The soaking process plays several key roles: First, it cleans and removes impurities. During the growth process, various impurities from the ocean, such as salt, silt, microorganisms, and soluble pigments, adhere to the surface of the natural material. Soaking and cleaning effectively remove these impurities, preventing them from entering the final agar product and affecting the purity, color, and gel properties of the agar. Second, it hydrates and swells, which is the most crucial role. The cell walls and internal structure of dried agar are contracted and shriveled. Through thorough soaking, water molecules penetrate into the algae tissue, allowing the cell walls and agar precursors to fully absorb water and swell. This process increases the contact area with the natural material, making subsequent irradiation treatment and thermal extraction easier on the target substance. It also softens the tissue structure, breaking down some secondary structures such as hydrogen bonds, leading to a looser overall structure and reducing the mechanical strength of the tissue, thus breaking down physical barriers for subsequent extraction. Third, it creates favorable conditions for irradiation (synergistic effect): Irradiation (such as electron beams and gamma rays) acts on substances through high-energy particles, directly breaking down the cell walls and molecular chains of plants. When Gracilaria is fully hydrated, the active particles (such as free radicals) generated by irradiation can transfer energy more evenly and effectively in the aqueous medium and initiate degradation reactions. One of the main goals of irradiation is to degrade the complex structure of polysaccharides and cellulose in the cell wall, thereby weakening the cell wall's strength. The cell wall, which has already expanded and softened after soaking, is more sensitive to irradiation, and irradiation can more efficiently "break it up." This forms a synergistic effect: soaking for physical softening and expansion → irradiation for chemical / structural degradation → ultimately, a significant increase in extraction efficiency.

[0009] In some embodiments, step S20 is followed by step S30: immersing the electron beam-irradiated natural substance in water and then filtering it under pressure to obtain the extract stock solution.

[0010] Since the cell walls of natural materials are destroyed by electron beam irradiation, but extract molecules remain inside the cells, when the extract is hydrophilic, this embodiment allows the extract to fully swell and dissolve in an aqueous environment by soaking the natural material. This allows the extract to detach from the cell matrix and dissolve in the water, forming an extract solution. Furthermore, as the extract dissolves, the soaking solution gradually becomes more viscous. This embodiment, through a thorough soaking process, allows the extract molecules to diffuse evenly into the water in a relatively static environment, avoiding significant viscous resistance caused by excessively high local concentrations during the initial pressurization phase. Simultaneously, compared to prolonged high-temperature cooking, electron beam irradiation combined with room-temperature or low-temperature soaking is a gentler physical extraction method, which can reduce the amount of extract dissolved. The thermal degradation of the sub-chains helps maintain the gel strength of the extract. After soaking, we obtain a solid-liquid mixture (natural residue + extract solution), and pressure filtration is key to separating them: First, pressure filtration achieves efficient separation and improves the extraction rate: relying solely on gravity filtration, the viscous extract solution is difficult to completely separate from the natural residue, resulting in a large amount of valuable extract solution adsorbed inside and on the surface of the residue, leading to a low extraction rate; second, pressure (whether positive or negative vacuum) provides a powerful driving force that forces these viscous liquids out of the tiny pores of the residue, maximizing extract recovery and significantly improving the extraction rate; third, pressure filtration shortens filtration time and improves efficiency: for industrial production, time is money. Pressure can greatly accelerate the filtration speed, shorten the entire production cycle, and improve production efficiency. The synergistic effect of combining soaking followed by pressure filtration: 1+1>2. This is because combining soaking and pressure filtration in sequence achieves perfect collaboration: On the one hand, the "loosen first, extract later" strategy: electron beam irradiation is like "loosening the soil" (destroying cell structure), soaking is like "watering" (allowing the extract to dissolve and diffuse), and pressure filtration is like "harvesting" (efficiently separating the product); On the other hand, soaking followed by pressure filtration optimizes the process and saves energy: without sufficient soaking, directly pressurizing dry or insufficiently swollen natural materials requires extremely high pressure, resulting in high energy consumption and poor efficiency; sufficient soaking makes the material "easy to press," thereby reducing the energy consumption and difficulty of the pressurization process.

[0011] In some embodiments, in step S10, soaking the natural substance is achieved by immersing it in water at room temperature for 2-3 hours. This ensures the soaking effect while preventing the extracts in the natural substance from being destroyed by excessively high or low temperatures.

[0012] In some embodiments, in step S30, the electron beam-irradiated natural material is immersed in water for 12 h ± 2 h. This allows for thorough swelling and dissolution of the extract in an aqueous environment through sufficient immersion of the natural material.

[0013] In some embodiments, step S100, which involves cutting the natural material into segments, is included before step S10. This not only improves the soaking efficiency of the subsequent soaking step but also the irradiation efficiency of the subsequent irradiation step, as well as the efficiency of subsequent soaking and pressure filtration.

[0014] In some embodiments, in step S30, the pressure of the extract stock solution obtained by pressure filtration of the natural substance after soaking in water is 0.1 kPa ± 0.02 kPa.

[0015] In some embodiments, step S40 is included after step S30: allowing the filtered extract stock solution to stand for 12h ± 2h. This allows precipitates to be removed, improving the purity of the extract.

[0016] In some embodiments, during step S20, when the electron beam irradiates the natural material, the natural material is laid flat. This flat placement ensures both the efficiency and uniformity of the electron beam irradiation.

[0017] In some embodiments, step S50 is included after step S40: the extract stock solution, which has been left to stand for 12h ± 2h, is dried at 60℃ ± 10℃ for at least 12 hours to obtain the extract. This ensures drying efficiency while preventing high temperatures from causing molecular chain breakage, deformation, or degradation of the extract, thus guaranteeing its quality and avoiding excessive costs. Furthermore, it effectively inhibits the growth of microorganisms (bacteria, molds) inherent to and attached to the natural product, preventing spoilage during storage and pretreatment. For example, by selecting a suitable drying temperature, these enzymes can be effectively inactivated, thereby protecting the integrity of the extract.

[0018] In some embodiments, in step S20, the total absorbed dose range of electron beam irradiation at an absorbed dose rate of 625 Gy / s and / or electron beam irradiation of the natural substance is 10 kGy to 150 kGy. This ensures that the electron beam can degrade the molecular structure of the natural substance and cause the extract molecules to generate free radicals due to energy absorption, thus achieving efficient extraction of the extract while simultaneously trimming the molecular chains of the extract.

[0019] According to one aspect of the present invention, the aforementioned method for extracting natural extracts is provided for use in the extraction of agar.

[0020] The electron beam irradiation method for agar extraction proposed in this application is a green and efficient extraction method. Firstly, the extraction speed is fast, requiring only a few seconds of irradiation to complete agar extraction, saving time, reducing production costs, and improving extraction efficiency compared to other methods. Secondly, the extraction process is clean and sterile, reducing the risk of microbial contamination, which is particularly important in the field of microbiology, as agar is commonly used as a culture medium for bacteria and other microorganisms. Thirdly, the extraction method uses radiation-induced degradation without the use of any chemical reagents, thus avoiding contamination of the extract and improving its purity. Fourthly, the extraction method requires no chemical reagents or solvents, making it an environmentally friendly agar extraction method that generates less waste and consumes less energy compared to other methods. Fifthly, by adjusting the absorbed dose and irradiation time, the degradation products can be controlled and adjusted to obtain the target extract.

[0021] In some implementations, the natural substance is a true red algae.

[0022] In some implementations, the natural material is a Gracilariaceae plant and / or a Gracilariaceae plant. Attached Figure Description

[0023] Figure 1 This is a schematic flowchart of the extraction method of natural extracts according to the first embodiment of the present invention; Figure 2 This is a schematic flowchart of the extraction method of natural extracts according to the second embodiment of the present invention; Figure 3 This is a schematic flowchart of the extraction method of natural extracts according to the third embodiment of the present invention; Figure 4 This is a schematic flowchart of the extraction method of natural extract according to the fourth embodiment of the present invention; Figure 5 This is a schematic flowchart of the extraction method of natural extract according to the fifth embodiment of the present invention; Figure 6 This is a schematic flowchart of the extraction method of natural extract according to the sixth embodiment of the present invention; Figure 7 A schematic diagram illustrating the reaction mechanism of agar backbone breakage during electron beam irradiation; Figure 8 This is a schematic diagram comparing the one-step electron beam irradiation extraction of agar for the natural extract method of this application with the traditional alkali treatment method, which requires at least four steps. Figure 9 This is a schematic diagram of the Fourier transform infrared spectra of *Gracilaria pulcherrima* seaweed after irradiation treatment with different absorbed doses. Figure 9Figure a in the figure is a schematic diagram of the Fourier transform infrared spectrum of agar for Gracilaria pulidonis after irradiation with different absorbed doses. Figure 9 Figure b in the text is Figure 9 A magnified view of part of figure a in the diagram; Figure 10 Scanning electron microscope (SEM) images of *Gracilaria fusiforme* seaweed treated with different absorbed doses of radiation. Figure 10 The absorbed radiation dose in figure a is 0 kGy; Figure 10 The absorbed radiation dose in Figure b is 10 kGy; Figure 10 The absorbed radiation dose in diagram c is 20 kGy; Figure 10 The absorbed radiation dose in the d-plot is 50 kGy; Figure 10 The absorbed radiation dose in diagram e is 100 kGy; Figure 10 The absorbed radiation dose in the f-figure is 150 kGy; Figure 11 Schematic diagram of TGA (thermogravimetric analysis) curves of agar extracted from different absorbed doses of radiation. Figure 11 Figure a in the diagram), and the schematic diagram of DTG (WeChat business hot spot curve). Figure 11 Figure b in the diagram) and a schematic diagram of DSC (differential scanning calorimetry curve) Figure 11 (Figure c in the text) Figure 12 The effect of different irradiation absorbed doses on the molecular weight of agar; Figure 13 The graph shows the relationship between different absorbed radiation doses and viscosity, gel strength, gel temperature, melting temperature, solution temperature, water retention, transmittance, and color; among them, Figure 13 Figure a in the diagram shows the relationship between the viscosity and gel strength of agar and the absorbed radiation dose. Figure 13 Figure b in the figure shows the relationship between the gelation temperature, melting temperature and solution temperature of different agars; Figure 13 Figure c in the figure is a schematic diagram of the water-holding capacity relationship of agar extracted with different absorption doses; Figure 13 Figure d in the figure shows the relationship between the color change of dissolved agar aqueous solution after irradiation and the absorbed dose in an air environment. Figure 14 The relative intensities of each peak under different irradiation absorbed doses; Figure 15 The image shows the ESR (electron spin resonance) spectrum of agar irradiated with an electron beam; among which, Figure 15 Figure a shows the ESR spectra of agar with different irradiated absorbed doses under room temperature conditions; Figure 15 Figure b shows the ESR spectrum changes of electron beam irradiated agar in air at different test temperatures; Figure 15Figure c shows the ESR spectra of agar annealed at 120°C in air for different durations (10-120 minutes) after irradiation with an absorbed dose of 150 kGy. Figure 15 Figure d in the figure shows the change of ESR spectrum of agar in air at room temperature over time after irradiation with a dose of 150 kGy; Figure 16 This is a schematic diagram showing the relative intensities of the three peaks and the free radical concentration of agar after electron beam irradiation as a function of time; where, Figure 16 Figure a shows the relative intensities of the three peaks observed in the agar after electron beam irradiation; Figure 16 Figure b shows the change in free radical concentration over time in agar irradiated with an absorbed dose of 150 kGy under room temperature air storage conditions. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0025] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising" or "including" include not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The terminology used herein is generally that commonly used by those skilled in the art; in case of any discrepancy with commonly used terminology, the terminology used herein shall prevail.

[0026] Furthermore, for ease of description, spatial relative terms such as “below,” “under,” “lower,” “above,” and “upper” may be used herein to describe the relationship between one element or component and another (or other) element or component as shown in the figure. In addition to the orientation shown in the figure, spatial relative terms are intended to include different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein can be interpreted accordingly.

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Figure 1 An exemplary method for extracting natural extracts according to a first embodiment of the present invention is shown.

[0029] like Figure 1 As shown, the extraction method for this natural extract includes the following steps: S20: The natural substance is irradiated with an electron beam before obtaining the natural extract.

[0030] In some embodiments, during step S20, when the electron beam irradiates the natural material, the natural material is laid flat, for example, in a tray. This ensures both the efficiency and uniformity of the electron beam irradiation, and also makes the material easy to handle.

[0031] In some embodiments, in step S20, the electron beam used to irradiate the natural substance is configured with an electron beam energy of 1.5 MeV ± 0.2 MeV, a power of 80 kW ± 10 kW, and / or an intensity of 1.4 mA ± 0.2 mA.

[0032] In some embodiments, in step S20, electron beam irradiation is performed at an absorbed dose rate of 625 Gy / s (Grey per second), and / or the total absorbed dose of the natural substance to the electron beam irradiation ranges from 10 kGy (kilogray) to 150 kGy, so as to ensure that the electron beam can degrade the molecular structure of the natural substance and enable the molecules of the extract to generate free radicals due to energy absorption, thereby achieving the trimming of the molecular chain of the extract and efficiently completing the extraction of the extract.

[0033] Because electron beams can degrade the molecular structure of natural substances and cause the molecules of extracts to generate free radicals by absorbing energy, the extraction of extracts can be efficiently completed while simultaneously trimming the molecular chains of the extracts. The extraction process does not require the use of specialized closed microwave extraction equipment, which greatly reduces the extraction cost. Since the extraction process uses electron beam irradiation, it can ensure that the extraction process is clean and sterile. Furthermore, since the extraction process does not use chemical reagents or solvents, it will not cause pollution to the extracts and the environment, and can also ensure the purity of the extracts.

[0034] Figure 2An exemplary method for extracting natural extracts according to a second embodiment of the present invention is shown.

[0035] like Figure 2 As shown, the main difference between this embodiment and the first embodiment of the natural extract extraction method is that, before step S20, step S10 is included: soaking the natural substance in water. On the one hand, soaking the natural substance in water can clean it and remove impurities (salt, silt, microorganisms, and soluble pigments, etc.) attached to it. On the other hand, it can cause the natural substance to hydrate and swell, which can increase the contact area of ​​the natural substance, making it easier for subsequent irradiation treatment and thermal extraction to act on the target substance; it can also soften the tissue structure: destroying some secondary structures such as hydrogen bonds, resulting in a looser overall structure and reducing the mechanical strength of the tissue, thus breaking down the physical barrier for subsequent extraction. Furthermore, it can create favorable conditions for irradiation (synergistic effect): irradiation (such as electron beams, gamma rays) acts on the substance through high-energy particles, which can directly break the cell walls and molecular chains of plants.

[0036] In some embodiments, in step S10, soaking the natural product is achieved by immersing the natural product in water at room temperature for 2-3 hours. Controlling the soaking time and temperature during soaking can ensure the soaking effect and prevent the extracts in the natural product from being destroyed due to excessively high or low temperatures.

[0037] Figure 3 An exemplary method for extracting natural extracts according to a third embodiment of the present invention is shown.

[0038] like Figure 3 As shown, the main difference between this embodiment and the second embodiment in the extraction method of natural extracts is that, before step S10, a step S100 is included: cutting the natural substance into segments. Cutting the natural substance before drying not only improves the soaking efficiency of the subsequent soaking step, but also improves the irradiation efficiency of the subsequent irradiation step, and also improves the efficiency of subsequent soaking and pressure filtration. In specific embodiments, the size of the segments can be adjusted according to requirements, and this application does not limit the specific size of the segments.

[0039] Figure 4 An exemplary method for extracting natural extracts according to a fourth embodiment of the present invention is shown.

[0040] like Figure 4 As shown, the main difference between this embodiment and the first embodiment in the extraction method of natural extracts is that, after step S20, a step S30 is included: the natural substance irradiated by an electron beam is immersed in water, and then filtered under pressure to obtain the extract stock solution. In some embodiments, the water used to immerse the natural substance can be tap water or deionized water.

[0041] In some embodiments, in step S30, the electron beam irradiated natural material is soaked in water for 12h±2h to allow the extract to fully swell and dissolve in the water environment through thorough soaking of the natural material.

[0042] In some embodiments, in step S30, the pressure of the extract stock solution obtained by pressure filtration of the natural substance after soaking in water is 0.1 kPa ± 0.02 kPa. In some embodiments, pressure filtration can be carried out in air. In some embodiments, pressure filtration is performed concurrently with filtration, and pressure filtration is stopped when filtration is completed.

[0043] Since the cell walls of natural materials are destroyed by electron beam irradiation, but extract molecules remain inside the cells, when the extract is hydrophilic, this embodiment allows the extract to fully swell and dissolve in an aqueous environment by soaking the natural material. This allows the extract to detach from the cell matrix and dissolve in the water, forming an extract solution. Furthermore, as the extract dissolves, the soaking solution gradually becomes more viscous. This embodiment, through a thorough soaking process, allows the extract molecules to diffuse evenly into the water in a relatively static environment, avoiding significant viscous resistance caused by excessively high local concentrations during the initial pressurization phase. Simultaneously, compared to prolonged high-temperature cooking, electron beam irradiation combined with room-temperature or low-temperature soaking is a gentler physical extraction method, which can reduce the amount of extract dissolved. The thermal degradation of the sub-chains helps maintain the gel strength of the extract. After soaking, we obtain a solid-liquid mixture (natural residue + extract solution), and pressure filtration is key to separating them: First, pressure filtration achieves efficient separation and improves the extraction rate: relying solely on gravity filtration, the viscous extract solution is difficult to completely separate from the natural residue, resulting in a large amount of valuable extract solution adsorbed inside and on the surface of the residue, leading to a low extraction rate; second, pressure (whether positive or negative vacuum) provides a powerful driving force that forces these viscous liquids out of the tiny pores of the residue, maximizing extract recovery and significantly improving the extraction rate; third, pressure filtration shortens filtration time and improves efficiency: for industrial production, time is money. Pressure can greatly accelerate the filtration speed, shorten the entire production cycle, and improve production efficiency. The synergistic effect of combining soaking followed by pressure filtration: 1+1>2. This is because combining soaking and pressure filtration in sequence achieves perfect collaboration: On the one hand, the "loosen first, extract later" strategy: electron beam irradiation is like "loosening the soil" (destroying cell structure), soaking is like "watering" (allowing the extract to dissolve and diffuse), and pressure filtration is like "harvesting" (efficiently separating the product); On the other hand, soaking followed by pressure filtration optimizes the process and saves energy: without sufficient soaking, directly pressurizing dry or insufficiently swollen natural materials requires extremely high pressure, resulting in high energy consumption and poor efficiency; sufficient soaking makes the material "easy to press," thereby reducing the energy consumption and difficulty of the pressurization process.

[0044] Figure 5 An exemplary method for extracting natural extracts according to a fifth embodiment of the present invention is shown.

[0045] like Figure 5As shown, the main difference between this embodiment and the fourth embodiment in the extraction method of natural extracts is that, after step S30, step S40 is included: the filtered extract stock solution is allowed to stand for 12h±2h to remove precipitates and improve the purity of the extract. It is then dried at 60℃±10℃ for at least 12 hours to obtain an extract with a water content of less than 5%. Drying the filtered extract stock solution at 60℃±10℃ ensures drying efficiency while preventing high temperatures from causing molecular chain breakage, deformation, or degradation, thus guaranteeing the quality of the extract and avoiding excessive costs. Furthermore, it effectively inhibits the growth of microorganisms (bacteria, molds) inherent to and attached to the natural product, preventing spoilage during storage and pretreatment. For example, by selecting a suitable drying temperature, these enzymes can be effectively inactivated, thereby protecting the integrity of the extract.

[0046] Figure 6 An exemplary method for extracting natural extracts according to a sixth embodiment of the present invention is shown.

[0047] like Figure 6 As shown, the main difference between this embodiment and the fifth embodiment in the extraction method of natural extracts is that, after step S40, a step S50 is included: the extract stock solution that has been left to stand for 12h±2h is dried at 60℃±10℃ for at least 12 hours to obtain an extract with a water content of less than 5%. Drying the filtered extract stock solution at 60℃±10℃ ensures drying efficiency while preventing high temperatures from causing molecular chain breakage, deformation, or degradation, thus guaranteeing the quality of the extract and avoiding excessive costs. Furthermore, it effectively inhibits the growth of microorganisms (bacteria, molds) inherent to and attached to the natural product, preventing spoilage during storage and pretreatment. For example, by selecting a suitable drying temperature, these enzymes can be effectively inactivated, thereby protecting the integrity of the extract.

[0048] According to one aspect of the present invention, the aforementioned method for extracting natural extracts is provided for use in the extraction of agar.

[0049] The essence of electron beam irradiation extraction of agar is to physically disrupt cell structure using high-energy rays (high-energy rays, such as electron beams and gamma rays, when penetrating algae cells, their energy is absorbed by components in the cell wall such as cellulose and hemicellulose, directly destroying the dense structure of the cell wall through radiation cleavage effect), and precisely cleaving the agar molecular chains through free radical chemistry. During irradiation, the agar molecules absorb energy, leading to the generation of free radicals (such as...). Figure 7As shown, under electron beam irradiation, whether directly or indirectly, free radicals are formed. These free radicals can interact with other molecules to initiate various reactions. By understanding the generation, stability, and interaction patterns of free radicals, the extraction process can be optimized to obtain higher yields of high-quality agar. For example, the higher the irradiation dose, the higher the concentration of free radicals generated, and the higher the concentration of free radicals, the more reactions can be initiated. Furthermore, since the radiation dose can affect the concentration of free radicals generated, the desired molecular chain of agar can be obtained by adjusting the irradiation dose.

[0050] The electron spin resonance (ESR) curve of electron beam-irradiated agar typically exhibits three symmetrical peaks (indicating the formation of free radicals on electron beam-irradiated agar, while unirradiated agar lacks free radicals, such as...). Figure 15 As shown); and the intensity of these peaks increases proportionally with the absorbed dose (e.g. Figure 15 As shown in Figure a), the absorbed dose range of the samples was 0–150 kGy. The ESR spectrum of the original *Gnaphalium affine* at room temperature did not show any signal corresponding to free radicals. However, the ESR spectrum of the irradiated *Gnaphalium affine* showed characteristic signals indicating the presence of free radicals. With increasing absorbed dose, the intensity of the ESR signal corresponding to free radicals in the irradiated sample gradually increased, while its peak position in the ESR spectrum remained unchanged (e.g., ...). Figure 15 (As shown in Figure a). This change in signal intensity reflects a corresponding change in the concentration level of free radicals captured in the irradiated agar due to the increase in absorbed dose. According to... Figure 15 As shown in Figure b, when the temperature during electron beam irradiation is above 90℃, the three symmetrical peaks of the electron spin resonance (ESR) curve of electron beam-irradiated agar weaken to almost nothing. According to... Figure 15 As can be seen from Figure c, after annealing agar with an absorbed dose of 150 kGy in air at 120°C for 10 minutes, the three symmetrical peaks of the electron spin resonance (ESR) curve of agar weaken to almost none.

[0051] The ESR spectra obtained from the treated agar were predominantly symmetrical, with a vertical g-factor (g⊥) of 2.008 for the hyperfine lines. However, some asymmetry was also observed in the spectra, which was thought to be due to peak overlap of the peroxide radical spectrum—since peroxide radicals typically exhibit asymmetric peaks, and their vertical g-factor (g⊥) is 2.008 ± 0.002.

[0052] like Figure 15As shown, the signal corresponding to peak 3 is mainly attributed to the formation of secondary alkyl radicals, which are generated by the irradiation of monosaccharide segments. The signal intensity increases with increasing absorbed dose. Since monosaccharide segments account for 75% of the agar composition, the signal of peak 3 mainly originates from the secondary alkyl radicals formed by the irradiation of these segments, and the response increases with increasing absorbed dose. Peak 2 corresponds to tertiary alkyl radicals derived from the initial irradiation-induced radicals, showing a significant change with increasing absorbed dose. The sharp increase in radical concentration at the initial absorbed dose can be attributed to the high sensitivity of polysaccharide polymers to high-energy radiation—significant chain scission occurs even at low absorbed doses, leading to a sharp increase in radical concentration. The signal of peak 1 is relatively weak and shows a steady upward trend with increasing absorbed dose. The relevant radicals mainly include tertiary alkyl radicals located on the ring and secondary alkyl radicals attached to the ring. The effect of this phenomenon is as follows: Figure 15 As shown in Figure a.

[0053] Figure 14 The linear relationship between absorbed dose and initial free radical concentration was shown in the dose range of 10–150 kGy, indicating that the concentration of free radicals increases with increasing irradiation dose.

[0054] ESR spectroscopy revealed the presence of both alkyl radicals and peroxy radicals in the irradiated agar. These radicals can react with oxygen molecules—due to the amorphous structure of agar, oxygen molecules easily diffuse into it. The radicals readily react with atmospheric oxygen to form peroxides and hydroperoxides.

[0055] The half-life of a free radical refers to the time required for its concentration level to decrease by half due to various chemical reactions. The actual half-life varies significantly depending on the type of free radical, its environment, and other substances that may interact with it. To investigate the effect of storage time on the degradation characteristics of free radicals, researchers periodically recorded the ESR spectra of irradiated agar after storing it at room temperature for different periods. Figure 15 As shown in Figure d, free radicals gradually decay during storage in air. The changes in the ESR spectrum over time are attributed to the coalescence or transformation of free radicals during storage. Figure 15 The d-plot shows that the decay rates of peaks 2, 1, and 3 decrease sequentially, with the recombination of secondary alkyl radicals being the main cause of this decay phenomenon. When the storage time reaches 3 days, the radical rearrangement process becomes dominant, causing the decay rates of peaks 1 and 3 to be faster than that of peak 2. The weakening of the ESR signal at room temperature is mainly due to the interaction of radicals with oxygen to generate peroxides.

[0056] Figure 16Figure a in the diagram shows the correlation between storage time and free radical concentration: the spectral profile of the sample stored in air for 15 days remained basically unchanged, while the free radical concentration decreased to about 50% of the initial value. This phenomenon indicates that the decay of free radicals at room temperature is mainly achieved through reaction and recombination with oxygen in the ambient air.

[0057] The decay behavior of free radicals in air is mainly affected by oxygen content. Due to its lower density and more rigid molecular chains, agar exhibits less free radical recombination, resulting in a longer free radical lifetime compared to other polymers. Free radicals react with oxygen in the air to form peroxide free radicals, whose decay is accelerated by oxidation. Simultaneously, to determine the half-life of irradiated agar, the peak with the fastest decay, 3 (…), is used… Figure 16 As shown in Figure b, its half-life is determined to be 10 days.

[0058] Agar is a polysaccharide extracted from specific types of seaweed, primarily from the Gracilaria and Gracilaria families. Due to its unique physicochemical properties, agar is widely used in the food, pharmaceutical, and cosmetic industries. Traditional agar extraction methods involve boiling seaweed in water, adding alkali or acidic chemicals to dissolve the agar, and then separating it from other components through filtration, precipitation, or centrifugation. Currently, chemical techniques such as alkali extraction are widely used in agar extraction from Gracilaria seaweed. Alkali treatment can effectively improve gel strength by removing sulfate groups from agar, but this process leads to significant depolymerization of polysaccharide chains, resulting in decreased agar yield and altered properties. Furthermore, alkali extraction is a complex process involving soaking and mechanical stirring, which is not only energy-intensive but also requires high temperatures and long extraction times. Figure 8 As shown, the electron beam irradiation method of this application for agar extraction requires only one electron irradiation step to break down molecular chains with a degree of polymerization (n) into molecular chains with a degree of polymerization (a). In contrast, the alkali treatment method requires four steps to break down molecular chains with a degree of polymerization (n) into molecular chains with a degree of polymerization (b). These four steps are: first, alkali treatment; second, dealkalization; third, rinsing and soaking; and fourth, acidification, where a < b << n. Therefore, the electron beam irradiation method of this application for agar extraction not only has fewer steps (only one) than the alkali treatment method (four steps), but also yields molecular chains with a lower degree of polymerization than those obtained by the alkali treatment method. The electron beam irradiation method for agar extraction proposed in this application achieves: efficient dissolution (disruption of cell barrier), molecular modification (reduction of sulfate content and regulation of molecular weight), and green energy saving (no strong alkali required, simplified steps); it compresses the traditional multi-step extraction process into one step, while simultaneously enabling targeted regulation of agar quality, providing a revolutionary solution for seaweed processing.

[0059] The electron beam irradiation method for agar extraction proposed in this application is a green and efficient extraction method. Firstly, the extraction speed is fast, requiring only a few seconds of irradiation to complete agar extraction, saving time, reducing production costs, and improving extraction efficiency compared to other methods. Secondly, the extraction process is clean and sterile, reducing the risk of microbial contamination, which is particularly important in the field of microbiology, as agar is commonly used as a culture medium for bacteria and other microorganisms. Thirdly, the extraction method uses radiation-induced degradation without the use of any chemical reagents, thus avoiding contamination of the extract and improving its purity. Fourthly, the extraction method requires no chemical reagents or solvents, making it an environmentally friendly agar extraction method that generates less waste and consumes less energy compared to other methods. Fifthly, by adjusting the absorbed dose and irradiation time, the degradation products can be controlled and adjusted to obtain the target extract.

[0060] In some embodiments, the natural substance is a true red algae.

[0061] In some embodiments, the natural substance is a Gracilariaceae plant and / or a Gracilariaceae plant.

[0062] The following specific examples illustrate the extraction method of natural extracts.

[0063] Example 1 The first step is to cut the seaweed (Gracilaria lemaneiformis, also known as sea lettuce) into small pieces; The second step is to soak a suitable amount of small sample pieces in water. The third step involves laying the sample flat in a tray and irradiating it with an electron beam at an absorbed dose rate of 625 Gy / s. The electron beam energy is 1.5 MeV, the power is 80 kW, and the intensity is 1.4 mA, resulting in a sample with a total absorbed dose of 50 kGy. The fourth step involves immersing the electron beam-irradiated sample in water for 12 hours, then pressing it at 0.1 kPa and filtering it to obtain the original agar extract solution. Fifth step: Let the obtained agar stand for 12 hours; Step 6: Dry the filtered agar extract stock solution at 60°C for 12 hours to obtain agar.

[0064] Example 2 The first step is to cut the seaweed into small pieces; The second step is to soak a suitable amount of small sample pieces in water. The third step involves laying the sample flat in a tray and irradiating it with an electron beam at an absorbed dose rate of 625 Gy / s. The electron beam energy is 1.3 MeV, the power is 70 kW, and the intensity is 1.2 mA, resulting in a sample with a total absorbed dose of 10 kGy. The fourth step involves immersing the electron beam-irradiated sample in water for 14 hours, then pressing it at 0.12 kPa and filtering it to obtain the original agar extract solution. Fifth step: Let the obtained agar stand for 10 hours; Step 6: Dry the filtered agar extract stock solution at 50°C for 14 hours to obtain agar.

[0065] Example 3 The first step is to cut the seaweed into small pieces; The second step is to soak a suitable amount of small sample pieces in water. The third step involves laying the sample flat in a tray and irradiating it with an electron beam at an absorbed dose rate of 625 Gy / s. The electron beam energy is 1.7 MeV, the power is 90 kW, and the intensity is 1.6 mA, resulting in a sample with a total absorbed dose of 150 kGy. The fourth step involves immersing the electron beam-irradiated sample in water for 10 hours, then pressing it at 0.08 kPa and filtering it to obtain the original agar extract solution. Fifth step: Let the obtained agar stand for 14 hours; Step 6: Dry the filtered agar extract stock solution at 70°C for 12 hours to obtain agar.

[0066] Example 4 The first step is to cut the seaweed into small pieces; The second step is to soak a suitable amount of small sample pieces in water. The third step is to lay the sample flat in the tray and irradiate it with an electron beam at an absorbed dose rate of 625 Gy / s to obtain a sample with a total absorbed dose of 20 kGy. The fourth step involves immersing the electron beam-irradiated sample in water for 13 hours, then applying a pressure of 0.11 kPa and filtering to obtain the original agar extract solution. Fifth step: Let the obtained agar stand for 11 hours; Step 6: Dry the filtered agar extract stock solution at 50°C for 13 hours to obtain agar.

[0067] Example 5 The first step is to cut the seaweed into small pieces; The second step is to soak a suitable amount of small sample pieces in water. The third step is to lay the sample flat in the tray and irradiate it with an electron beam at an absorbed dose rate of 625 Gy / s to obtain a sample with a total absorbed dose of 100 kGy. The fourth step involves immersing the electron beam-irradiated sample in water for 11 hours, then pressing it at 0.09 kPa and filtering it to obtain the original agar extract solution. Fifth step: Let the obtained agar stand for 13 hours; Step 6: Dry the filtered agar extract stock solution at 65°C for 15 hours to obtain agar.

[0068] Schematic diagram of Fourier transform infrared spectra of Gracilaria pulidonis after irradiation with different absorbed doses, as shown in Figure 1. Figure 9 As shown, according to Figure 9 It can be seen that the FT-IR (Fourier Transform Infrared) spectra obtained with irradiated absorbed doses of 10 kGy to 150 kGy are at 1376 cm⁻¹. -1 and 1250cm -1 The characteristic peaks observed at [location missing] confirm the presence of ester-sulfate groups, indicating that the product obtained by electron beam irradiation possesses certain chemical and biological activity, while the product obtained without electron beam irradiation lacks ester-sulfate groups. Simultaneously, the FT-IR (Fourier Transform Infrared) spectra obtained with irradiated absorbed doses of 10 kGy to 150 kGy show peaks at 1081 cm⁻¹. -1 The absorption peak at 1250 cm⁻¹ corresponds to the vibration of the galactose skeleton, indicating that the product obtained by electron beam irradiation is agar (because the galactose skeleton is the basic structural unit of agar); moreover, the absorption peak of *Gnaphalium affine* treated with electron beam irradiation at 1250 cm⁻¹ corresponds to the vibration of the galactose skeleton. -1 A significant characteristic peak was observed at this location, consistent with the results of the highest sulfate content test, indicating that electron beam-assisted extraction can effectively remove the unstable sulfate group at the C6 position of galactose, thereby improving the intensity of the obtained agar. Furthermore, an 804 cm⁻¹ peak was observed in the FT-IR (Fourier Transform Infrared) spectra obtained with irradiated absorbed doses ranging from 10 kGy to 150 kGy. -1 With 846cm -1The significant characteristic peaks at the C-2 and C-4 positions of the 3,6-endoether-L-galactose and D-galactose units, respectively, correspond to the vibrations of the sulfate groups at these positions. This indicates that the agar extracted using the electron beam irradiation method described in this application has better quality. (The sulfate group is a characteristic functional group of the agar sugar chain. The intact retention of the sulfate group at the C-4 position indicates that irradiation did not damage the core chemical structure of the agar. This avoids excessive degradation of chain segments or loss of groups, resulting in a more stable basic framework for the gel network and providing structural support for subsequent performance. The presence of the sulfate group enhances the interaction between agar molecules, improving gel strength and toughness, making it more durable after molding at the same concentration, and exhibiting stronger functional activity and compatibility. The sulfate group is a key site for agar to exert biological activities (such as antibacterial and adsorption promotion). Its intact retention results in more prominent functional activity. When mixed with other substances (such as biological reagents and food additives), the chemical properties are more stable, less prone to reaction leading to performance degradation, and have better compatibility.) The FT-IR (Fourier Transform Infrared Spectroscopy) spectra obtained with irradiated absorbed doses of 10 kGy to 150 kGy show a peak at 850 cm⁻¹. -1 The presence of a faint characteristic peak nearby confirms the presence of a sulfate group at the C4 position of D-galactose-4-sulfate, indicating that the agar extracted using the electron beam irradiation method described in this application has better quality (e.g., higher purity and application compatibility). This is because the irradiation extraction process does not introduce additional chemical reagents and does not damage the characteristic groups, indicating that the product has fewer impurities and higher purity; moreover, the structure is stable and the functional groups are intact, making it suitable for more demanding application scenarios (such as high-precision microbial culture and medical carrier materials), and its applicability is wider.

[0069] Scanning electron microscope (SEM) images of *Gnaphalium affine* obtained by irradiating it with different doses of electron beam using the extraction method described in this application are shown below. Figure 10 As shown, according to Figure 10 It is known that exposure to ionizing radiation causes changes in the microstructure of Gracilaria fusiforme: within the absorbed dose range of 0 kGy to 150 kGy, as the absorbed dose increases, the surface of Gracilaria fusiforme gradually becomes smooth and other structural defects appear. Specifically, SEM (scanning electron microscopy) image analysis shows that the unirradiated sample maintains an intact fibrous structure, indicating that irradiation treatment is insufficient to destroy its internal structure and effectively extract internal active ingredients. With increasing absorbed dose, the molecular structure of Gracilaria fusiforme dissociates, resulting in a significant change in the surface morphology of the irradiated Gracilaria fusiforme compared to the unirradiated sample; due to the breakage of molecular chain segments and the reduction of impurities, the surface of the irradiated Gracilaria fusiforme exhibits an increased granular structure; when the absorbed dose continues to increase, the sample gradually transforms into a gel state and loses its fibrous structure. This phenomenon strongly confirms that high-dose treatment can effectively break molecular chains, thereby promoting the dissolution of internal active ingredients.

[0070] The thermal stability of agar is a key property determining its practical application and service temperature. This study determined the thermal stability of radiation-treated agar using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA was used to examine the thermal degradation process of molecular chains, while DSC was used to assess the migration rate of molecular chains during heating. Figure 11 As shown in Figure a, the initial decomposition temperature of agar did not change significantly with increasing absorbed dose. This is because the water molecules adsorbed by the agar molecules cause the initial decomposition temperature to stabilize at approximately 80℃. Simultaneously, both the maximum decomposition temperature and the decomposition intensity decreased sharply with increasing absorbed dose, indicating a significant decrease in molecular weight during irradiation. This result is consistent with the molecular weight analysis data. Figure 12 In addition, the residual amount gradually increases at 800℃, which may be due to the cross-linking of some molecular chains during irradiation, resulting in an increase in the degree of intermolecular cross-linking and thus a gradual increase in the residual char amount. Figure 11 Thermogravimetric curves (TGA) of different agar samples are shown. With increasing absorbed dose, the weight loss intensifies, and the pyrolysis peak shifts towards lower temperatures. The approximately 2%-10% mass loss observed in the 50-200℃ temperature range can be attributed to the presence of trace amounts of free water in the samples. The water loss rate can also be used to assess the water-holding capacity of the samples: with increasing absorbed dose, the dehydration rate increases synchronously, indicating that high-energy radiation disrupts the main chain segments, reducing the degree of cross-linking between agar molecules, thus leading to a decrease in water retention capacity. This demonstrates that radiation is an effective method for extracting agar from seaweed. Simultaneously, the water loss rate was observed to be lower in the high-absorbed-dose radiation group than in the low-dose group, possibly due to the reduced thermal stability of agar containing more sulfate groups in high-dose radiation. In the 200-350℃ temperature range, all samples exhibited rapid weight loss. Subsequently, the mass change tended to level off, but it was clearly observed that the magnitude of mass loss decreased with increasing absorbed dose, attributed to the presence of sulfonic acid groups. Figure 11 b as Figure 11 The first derivative curve of a more precise figure reveals the trend: as the absorbed dose increases, the peak intensity continuously weakens, further illustrating that high-energy radiation can break the chemical bonds of agar molecules, thereby enabling the effective utilization of agar molecules. DSC technology determines the thermal properties of agar (such as melting temperature and heat capacity) by measuring the heat flow changes during sample heating / cooling. Figure 11 As shown in c, all samples exhibit two endothermic peaks: the first broad peak is located near 125℃, which originates from small molecule compounds and water molecules generated by molecular chain breakage; the second endothermic peak is located near 175℃. As the absorbed dose increases, this peak becomes significantly broader and shifts towards lower temperatures, indicating that the molecular weight of agar decreases significantly with increasing radiation dose. This result is consistent with the conclusions of TGA and previous experiments.

[0071] according to Figure 13As shown in Figure a, the gel strength initially increases and then decreases with increasing absorbed dose: at lower doses, molecular chain cross-linking dominates, leading to increased strength (which begins to decline when the absorbed dose is around 15 kGy); however, as the dose continues to increase, the strength decreases again due to the breakage of sulfonic acid groups; at high absorbed doses, *Gnaphalium affine* exhibits a significant lysis trend, further inhibiting the increase in gel strength. The viscosity of irradiated agar also shows a similar pattern: at low doses, it slightly increases due to the dominance of molecular chain cross-linking (reaching its highest viscosity at around 20 kGy); combined with… Figure 13 As shown in Figure a, the curves of gel strength versus absorbed radiation dose and viscosity versus absorbed radiation dose reveal that a critical point is reached at an absorbed dose of 50 kGy. Beyond this critical point, the decrease in viscosity is primarily due to cleavage. It is noteworthy that the functional properties of agar are correlated with the absorbed dose, but the effect is most significant at lower doses (50 kGy). Therefore, 50 kGy is considered the optimal absorbed dose.

[0072] according to Figure 13 As shown in Figure b, the gelation temperature, melting temperature, and solution temperature of agar decrease with increasing radiation dose after the absorbed radiation dose reaches approximately 50 kGy.

[0073] Figure 13 Figure c shows the relationship between the percentage of transmittance and water retention of agar samples at a wavelength of 700 nm and the absorbed radiation dose. The transparency of agar varies significantly with the absorbed dose. High-dose irradiation has a dual effect on the properties of agar: on the one hand, radiation induces the formation of certain conjugated structures in the molecular chains, which deepens the color of the product; on the other hand, the free radicals generated by radiation accelerate the oxidation of organic matter (especially coloring proteins) in the product, resulting in a significant decrease in the transparency of agar with increasing absorbed dose. Agar exhibits optimal transmittance at an absorbed dose of approximately 50 kGy, and its transmittance decreases with increasing or decreasing absorbed radiation dose on both sides of this 50 kGy level. The abundant hydroxyl groups in agar endow it with excellent hydrophilicity, significantly enhancing its water-binding capacity. Radiation-induced micro-crosslinking at low absorbed doses enhances water absorption and retention properties, and the three-dimensional network of hydrophilic polymers can absorb and retain a large amount of water. However, with increasing dose, the dominant effect of molecular micro-crosslinking gradually shifts to radiation-induced degradation, leading to the destruction of the three-dimensional network structure and a sharp decrease in water retention. This result is consistent with the conclusions of the aforementioned study on the physicochemical properties of irradiated agar.

[0074] Figure 13The photograph in Figure d shows the color change of dissolved agar solution after irradiation in an air environment. It can be observed that the color of the solution gradually deepens with increasing absorbed dose. As the absorbed dose continues to increase, the transparency and color of the resulting agar become significantly more pronounced. This is mainly due to the free radical coupling or transformation during irradiation, which alters the light absorption characteristics and affects the color. In addition, it can also induce oxidation of the polymer matrix, changing the chromophore structure and thus affecting the color performance.

[0075] according to Figure 13 It can be seen that the functional properties of agar are related to the absorption dose, but the effect is most significant at a lower dose (50kGy). At this dose, the viscosity of agar is relatively low, the gel strength is relatively high, and the melting temperature is relatively low. Overall, the extracted agar has the best comprehensive performance at a dose of 50kGy.

[0076] The experimental data above demonstrates the crucial role of electron beam irradiation-induced free radicals in the entire process. By balancing chain scission and cross-linking reactions (e.g., by controlling the absorbed dose), agar with ideal gel strength and transparency can be obtained. Agar obtained through electron beam irradiation exhibits ideal properties: high gel strength, moderate viscosity, and low dissolution, melting, and gelation temperatures.

[0077] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A method for extracting natural extracts, characterized in that, Includes the following steps: S20: The natural substance is irradiated with an electron beam before obtaining the natural extract.

2. The method for extracting natural extracts according to claim 1, characterized in that, The process includes step S10 before step S20: soaking the natural substance; and / or The process includes step S30 after step S20: immersing the electron beam-irradiated natural substance in water and then filtering it under pressure to obtain the original extract solution.

3. The method for extracting natural extracts according to claim 2, characterized in that, In step S10, soaking the natural substance is achieved by: immersing the natural substance in water at room temperature for 2-3 hours; and / or In step S30, the natural substance irradiated by electron beam is immersed in water for 12h±2h.

4. The method for extracting natural extracts according to claim 2, characterized in that, The process includes step S100 before step S10: cutting the natural material into segments; and / or In step S30, the pressure of the extract stock solution obtained by pressure filtration of the natural substance after soaking in water is 0.1 kPa ± 0.02 kPa.

5. The method for extracting natural extracts according to claim 4, characterized in that, Following step S30, step S40 is further included: allowing the filtered extract stock solution to stand for 12h ± 2h; and / or In step S20, the natural material is laid flat when the electron beam irradiates it.

6. The method for extracting natural extracts according to claim 5, characterized in that, The process includes step S50 after step S40: drying the extract stock solution that has been left to stand for 12h±2h at 60℃±10℃ for more than 12 hours to obtain the extract.

7. The method for extracting natural extracts according to any one of claims 1 to 6, characterized in that, In step S20, the total absorbed dose range of electron beam irradiation and / or electron beam irradiation of natural substances is 10kGy to 150kGy, with an absorbed dose rate of 625Gy / s.

8. The application of the extraction method of the natural extract according to any one of claims 1 to 7 in the extraction of agar.

9. The application of the extraction method for natural extracts according to claim 8 in the extraction of agar, characterized in that, The natural substance is a plant belonging to the class Rhodophyta.

10. The application of the extraction method for natural extracts according to claim 9 in the extraction of agar, characterized in that, The natural substances are plants of the Gracilariaceae family and / or the Glechoceae family.

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