Plant-based essential oil blend, preparation method therefor, and use thereof

Abstract

A method for preparing a plant-based essential oil blend, comprising: mixing dried lemon slices, mint, and eagle tree tea into a mixed powder, carrying out supercritical carbon dioxide extraction, and collecting the extract; dripwise adding a carboxymethyl-β-cyclodextrin solution to a mixture of eugenol and thymol; carrying out ultrasonic treatment to obtain an ultrasonic mixed solution; letting same stand, performing centrifugation, and collecting a supernatant; carrying out drying treatment to obtain a white powdery inclusion compound; adding lecithin, Tween 80, disodium pyrophosphate, and deionized water to the extract; heating and stirring same, and continuing to add the inclusion compound; homogenizing same to obtain a nano-emulsion; then adding gelatin and propylene glycol; heating and maintaining the temperature; and cooling same to obtain the plant-based essential oil blend. The essential oil blend of the present invention has antibacterial and antioxidant effects, has a strong antibacterial ability against Botrytis cinerea and Penicillium spp, and has a DPPH free radical scavenging rate of greater than or equal to 90%. In the present invention, by means of nano-encapsulation, the essential oil active ingredient is embedded in carboxymethyl-β-cyclodextrin and co-encapsulated with liposomes to achieve slow release, thereby effectively prolonging the antioxidant and antibacterial performance.

Description

A plant-based compound essential oil, its preparation method and application Technical Field

[0001] This invention relates to the field of plant essential oil preparation technology, specifically to a plant compound essential oil, its preparation method, and its application. Background Technology

[0002] Plant essential oils are a class of aromatic substances extracted from different tissues and parts of higher plants, such as flowers, leaves, roots, stems, and fruits. They are volatile, oily liquids composed of phenols, terpenes, aldehydes and ketones, alcohols, acids, and aromatic compounds. Among them, phenols, terpenes, and aldehydes and ketones are the main antibacterial components, while alcohols, ethers, and hydrocarbons also have a certain degree of antibacterial effect. Plant essential oils possess antibacterial, antifungal, and antioxidant properties. As broad-spectrum bactericides, their high efficiency and long-lasting effects have led to their wide application value in various fields. For example, in the food and agricultural products sector, essential oils can be used as functional food additives to impart antioxidant activity and enhance nutritional value. They can also serve as natural preservatives and freshness-preserving agents to delay product spoilage. In the cosmetics and personal care sectors, they can eliminate free radicals in the skin, reduce wrinkles and age spots, inhibit scalp fungi, and suppress oral pathogens. In the pharmaceutical and health product sectors, essential oils can replace antibiotics as natural antibacterial drugs. In the agricultural sector, essential oils can replace chemical pesticides to prevent and control plant diseases.

[0003] However, single essential oils are not ideal for antibacterial and preservative effects, and their antioxidant, antibacterial, and bacteriostatic properties are not long-lasting or durable. Therefore, multiple essential oils need to be used in combination to improve their antibacterial effect. However, when multiple antibacterial essential oils are combined, the significant differences in the properties of their components lead to mutual interference, resulting in poor stability, easy layering, and sedimentation, causing product failure and unsatisfactory durability. Summary of the Invention

[0004] The purpose of this invention is to provide a plant-based compound essential oil.

[0005] Another objective of this invention is to provide a method for preparing plant-based compound essential oils.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A method for preparing a plant-based compound essential oil, characterized by comprising the following steps:

[0008] (1) Take lemon slices and freeze-dry them into dried lemon slices. Mix the dried lemon slices, mint and eagle tea and grind them into a mixed powder.

[0009] (2) Place the mixed powder in a supercritical carbon dioxide extractor for extraction and collect the extract;

[0010] (3) Add carboxymethyl-β-cyclodextrin solution dropwise to the mixture of eugenol and thymol, stir to form a suspension, sonicate to obtain an ultrasonic mixture, centrifuge to collect the supernatant, and dry to obtain a white powdery inclusion complex.

[0011] (4) Add lecithin, Tween 80, disodium pyrophosphate and deionized water to the extract prepared in step (2), heat and stir, and then add the inclusion complex from step (3). Homogenize to obtain nanoemulsion.

[0012] (5) Add gelatin and propylene glycol to the nanoemulsion, heat and keep warm, and then cool to obtain plant compound essential oil.

[0013] Furthermore, based on weight, the amounts of each component used in the preparation process are as follows: 18 parts eugenol, 10-12 parts thymol, 10-15 parts dried lemon slices, 5-8 parts peppermint, 5-8 parts eagle tea, 50-55 parts carboxymethyl-β-cyclodextrin, 10-12 parts gelatin, 5-7 parts propylene glycol, 3-5 parts Tween 80, 0.5-0.7 parts disodium pyrophosphate, 12-15 parts lecithin, and 20-30 parts deionized water.

[0014] Furthermore, the dried lemon slices in step (1) are obtained by washing lemons, cutting them into slices with a thickness of about 0.3 to 0.5 cm, and then freeze-drying them.

[0015] Furthermore, the freeze-drying process involves lowering the temperature to -18 to -22°C at a rate of 5 to 7°C / min, holding for 6 to 8 hours, qualitatively determining the temperature, then evacuating to -0.05 to -0.08 MPa, raising the temperature to -8 to -12°C at a rate of 3 to 5°C / min, holding for 2 to 3 hours, then raising the temperature to 12 to 15°C within 1 to 2 hours and holding for 3 to 5 hours, and then raising the temperature to 25 to 30°C within 30 to 60 minutes and holding for 6 to 8 hours. The product is then removed to obtain dried lemon slices.

[0016] Furthermore, in step (2), the extraction is carried out using propylene glycol, anhydrous ethanol and deionized water as entrainers, with a carbon dioxide flow rate of 12-15 kg / h, a pressure of 25-30 MPa, a temperature of 35-40°C and an extraction time of 2-4 h.

[0017] Furthermore, the mass ratio of propylene glycol, anhydrous ethanol, and deionized water in the entrainer is 3-5:15-20:70-75, and the mass ratio of the entrainer to the mixed powder is 1-2:1.

[0018] In this invention, carbon dioxide fluid, which is relatively lipid-soluble, is used as the extractant, while a water-soluble entrainer is selected. On the one hand, the use of ethanol solution in combination with propylene glycol and deionized water as entrainers can enhance the penetration ability of the solvent into lemon slices, peppermint, and eagle tea, thereby improving the extraction efficiency. On the other hand, the synergistic effect of the water-soluble entrainer and carbon dioxide can limit the polarity distribution of the target substances, enabling selective extraction of components with different polarities, thus obtaining extracts with higher antibacterial activity.

[0019] Furthermore, in step (3), the carboxymethyl-β-cyclodextrin solution is obtained by mixing carboxymethyl-β-cyclodextrin and deionized water at a mass ratio of 1:10-15 and stirring and heating at 20-30 rpm to 50-60°C.

[0020] Furthermore, in step (3), the stirring rate is 20-30 rpm and the stirring time is 15-20 min to obtain a suspension.

[0021] Furthermore, in step (3), the frequency of ultrasonic treatment is 35-40 kHz, the temperature is 50-60 ℃, and the ultrasonic treatment lasts for 2-3 hours to obtain an ultrasonic mixture.

[0022] Furthermore, in step (3), the static centrifugation involves cooling the ultrasonic mixture to room temperature, letting it stand for 8 to 10 hours, and then centrifuging it at 8000 to 10000 rpm for 15 to 20 minutes to collect the supernatant.

[0023] Furthermore, in step (3), the drying process involves drying the supernatant under a vacuum of -0.05 MPa to -0.08 MPa and a drying temperature of 40 to 45°C until a constant weight is obtained, resulting in a white powdery inclusion compound.

[0024] Furthermore, in step (4), the heating and stirring temperature is 30-40°C, the stirring speed is 20-30 rpm, and the stirring time is 10-15 min.

[0025] Furthermore, in step (4), the homogenization is started at a homogenization speed of 2000-3000 rpm, and after homogenization for 5-10 minutes, the homogenization speed is increased to 5000-7000 rpm and homogenization continues for 3-5 minutes. Then, the homogenization speed is further increased to 9000-10000 rpm and homogenization continues for 20-30 minutes to obtain the nanoemulsion.

[0026] Furthermore, in step (5), the heating and heat preservation temperature is 40-45℃, and the stirring is carried out at 20-30 rpm for 2-3 hours during the heat preservation process, and then the mixture is naturally cooled to room temperature.

[0027] Most specifically, a method for preparing a plant-based compound essential oil is characterized by comprising the following steps:

[0028] (1) Take lemons, wash them clean, and cut them into slices with a thickness of about 0.3 to 0.5 cm. Cool them down to -18 to -22°C at a rate of 5 to 7°C / min and keep them for 6 to 8 hours. After qualitative analysis, vacuum them to -0.05 to -0.08 MPa and heat them up to -8 to -12°C at a rate of 3 to 5°C / min. Keep them for 2 to 3 hours. Then heat them up to 12 to 15°C within 1 to 2 hours and keep them for 3 to 5 hours. Then heat them up to 25 to 30°C within 30 to 60 minutes and keep them for 6 to 8 hours to obtain dried lemon slices. Mix the dried lemon slices, mint and eagle tea together and grind them. Grind them through a 12-mesh sieve to obtain mixed powder.

[0029] (2) Place the mixed powder in the extraction vessel of a supercritical carbon dioxide extractor, add the entrainer, set the carbon dioxide flow rate to 12-15 kg / h, the pressure to 25-30 MPa, the temperature to 35-40℃, and the extraction time to 2-4 h. After extraction, collect the extract. The entrainer is composed of propylene glycol, anhydrous ethanol, and deionized water in a mass ratio of 3-5:15-20:70-75, and the mass ratio of the mixed powder to the entrainer is 1:1-2.

[0030] (3) Add a 25%–30% carboxymethyl-β-cyclodextrin solution to the mixture of eugenol and thymol, stir at 20–30 rpm for 15–20 min to form a suspension, sonicate at 35–40 kHz and 50–60 °C for 2–3 h to obtain an ultrasonic mixture, let stand for 8–10 h, centrifuge at 8000–10000 rpm for 15–20 min, collect the supernatant, and dry the supernatant at a vacuum of -0.05 MPa to -0.08 MPa and a drying temperature of 40–45 °C to constant weight to obtain a white powdery inclusion complex.

[0031] (4) Add lecithin, Tween 80, disodium pyrophosphate and deionized water to the extract prepared in step (2), heat to 30-40°C, stir at 20-30 rpm for 15-20 min, and slowly add the white powder inclusion complex prepared in step 4 under stirring conditions. After the addition is complete, continue stirring for 10-15 min, and then place it in a high-speed homogenizer. First, start the homogenization speed at 2000-3000 rpm, homogenize for 5-10 min, then increase the homogenization speed to 5000-7000 rpm, continue homogenizing for 3-5 min, then increase the homogenization speed to 9000-10000 rpm, and continue homogenizing for 20-30 min to obtain a nanoemulsion.

[0032] (5) Heat the nanoemulsion at 20-30 rpm to 40-45°C, add gelatin and propylene glycol, continue stirring for 2-3 hours under heat preservation conditions, and cool to room temperature to obtain plant compound essential oil;

[0033] The components used in the preparation process, by weight, are: eugenol 15-20 parts, thymol 10-12 parts, lemon 10-15 parts, peppermint 5-8 parts, eagle tea 5-8 parts, carboxymethyl-β-cyclodextrin 50-55 parts, gelatin 10-12 parts, propylene glycol 5-7 parts, Tween 80 3-5 parts, disodium pyrophosphate 0.5-0.7 parts, lecithin 12-15 parts, and deionized water 20-30 parts.

[0034] Because a specific extraction process is used, the antibacterial active ingredients in the extract are enhanced, which can improve the antibacterial activity of the final preservative. However, since the extract contains water-soluble and fat-soluble substances, and the remaining effective components, eugenol and thymol, are fat-soluble, the mixture of multiple components with different properties is prone to component stratification. Furthermore, fat-soluble components such as eugenol and thymol are easily volatilized, oxidized, and hydrolyzed. These factors result in poor preservation duration and longevity of the preservative essential oil.

[0035] In this invention, thymol and eugenol are encapsulated with carboxymethyl-β-cyclodextrin and then hydrated together with the extract to form liposomes. This creates a dual loading of lipid-soluble components through encapsulation and membrane embedding, increasing the overall encapsulation efficiency of the liposomes. Carboxymethyl-β-cyclodextrin encapsulates the lipid-soluble eugenol and thymol, forming a pseudo-water-soluble complex. This not only mitigates the volatilization of both components but also prevents their precipitation or aggregation in the aqueous phase due to low solubility. The hydrophilic carboxymethyl group (-COO-) in carboxymethyl-β-cyclodextrin is enriched in the aqueous environment of the liposomes, stabilizing the water-soluble components in the extract, inhibiting phase separation from the lipid-soluble components, and reducing the problems of stratification and sedimentation. The water-soluble components dissolve directly in the water core of the liposomes. During use, water-soluble components are preferentially released rapidly through lipid membrane pores or rupture, achieving rapid onset of action. Secondly, lipid-soluble components in the extract are released slowly. Finally, thymol and eugenol form a dual controlled release with the lipid membrane bilayer through the inclusion effect of carboxymethyl-β-cyclodextrin, resulting in a gradient release with different time effects, which prolongs the duration of the active ingredient's efficacy.

[0036] During the formation of the antibacterial film, if the film is too rigid, it will be difficult to retain moisture, and the antibacterial film will easily fall off. If the film is too soft, it will be easily damaged and deformed. In this invention, gelatin and propylene glycol are used together to form the film. Gelatin provides support for the propylene glycol film, while propylene glycol solves the problem of the gelatin film being too rigid and easy to fall off. The two complement each other, ultimately forming a continuous and smooth antibacterial film with suitable hardness, effectively reducing the loss of moisture from fruits and vegetables. The formation of the continuous antibacterial film allows the antibacterial nanoemulsion to adhere evenly inside, further improving the antibacterial and preservative effects.

[0037] A plant-based compound essential oil is characterized by the following steps: The extract is prepared by supercritical carbon dioxide extraction of dried lemon slices, peppermint, and eagle tea into a mixed powder; eugenol and thymol are added to a carboxymethyl-β-cyclodextrin solution and ultrasonically treated to prepare an inclusion complex; lecithin, Tween 80, disodium pyrophosphate, and deionized water are added to the extract; the mixture is heated and stirred, and the inclusion complex is continuously added; the mixture is homogenized to form a nanoemulsion; gelatin and propylene glycol are added to the nanoemulsion; the mixture is heated and kept at a constant temperature; and after cooling, the plant-based compound essential oil is obtained.

[0038] Furthermore, based on weight, the amounts of each raw material component in the preservative essential oil are as follows: eugenol 15-20 parts, thymol 10-12 parts, dried lemon slices 10-15 parts, peppermint 5-8 parts, eagle tea 5-8 parts, carboxymethyl-β-cyclodextrin 50-55 parts, gelatin 10-12 parts, propylene glycol 5-7 parts, Tween 80 3-5 parts, disodium pyrophosphate 0.5-0.7 parts, lecithin 12-15 parts, and deionized water 20-30 parts.

[0039] Furthermore, the extraction uses propylene glycol, anhydrous ethanol, and deionized water as entrainers, with a carbon dioxide flow rate of 12–15 kg / h, a pressure of 25–30 MPa, a temperature of 35–40 °C, and an extraction time of 2–4 h.

[0040] Furthermore, the mass ratio of propylene glycol, anhydrous ethanol, and deionized water in the entrainer is 3-5:15-20:70-75, and the mass ratio of the entrainer to the mixed powder is 1-2:1.

[0041] Furthermore, the carboxymethyl-β-cyclodextrin solution is obtained by mixing carboxymethyl-β-cyclodextrin and deionized water at a mass ratio of 1:10-15, and stirring and heating at 20-30 rpm to 50-60°C.

[0042] Furthermore, the ultrasonic treatment frequency is 35-40 kHz, the temperature is 50-60 °C, and the ultrasonic treatment lasts for 2-3 hours to obtain an ultrasonic mixture.

[0043] Furthermore, the homogenization is started at a homogenization speed of 2000-3000 rpm, and after homogenization for 5-10 minutes, the homogenization speed is increased to 5000-7000 rpm and homogenization continues for 3-5 minutes. Then, the homogenization speed is further increased to 9000-10000 rpm and homogenization continues for 20-30 minutes to obtain the nanoemulsion.

[0044] Furthermore, the heating and heat preservation involves stirring the nanoemulsion at 20-30 rpm and heating it to 40-45°C, adding gelatin and propylene glycol, continuing to stir under heat preservation conditions for 2-3 hours, and then naturally cooling it to room temperature.

[0045] The application of the above-mentioned plant compound essential oils in the preservation of fruits and vegetables.

[0046] The present invention has the following technical effects:

[0047] The plant-based compound essential oil of this invention has antibacterial and antioxidant effects. In terms of antibacterial properties, it exhibits strong inhibitory activity against Botrytis cinerea and Penicillium wilt. In terms of antioxidant properties, it has a DPPH free radical scavenging rate of ≥90%. This invention utilizes nano-encapsulation technology to achieve slow release of the active ingredients of the essential oil by encapsulating them in carboxymethyl-β-cyclodextrin and co-encapsulating them in liposomes, effectively prolonging the antioxidant and antibacterial properties. Detailed Implementation

[0048] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0049] Example 1

[0050] A method for preparing a plant-based compound essential oil includes the following steps:

[0051] (1) Take lemons, wash them clean, cut them into slices with a thickness of about 0.3 to 0.5 cm, lower the temperature to -20°C at a cooling rate of 6°C / min, keep it for 7 hours, after qualitative analysis, vacuum to -0.05 to -0.08 MPa, raise the temperature to -10°C at a rate of 4°C / min, keep it for 2.5 hours, then raise the temperature to 14°C within 1.5 hours and keep it for 4 hours, then raise the temperature to 30°C within 40 minutes and keep it for 6 hours to obtain dried lemon slices. Mix 12 parts of dried lemon slices, 6 parts of mint and 6 parts of eagle tea and grind them. Grind them through a 12-mesh sieve to obtain mixed powder.

[0052] (2) Place the mixed powder in the extraction vessel of a supercritical carbon dioxide extractor, add an entrainer, set the carbon dioxide flow rate to 14 kg / h, the pressure to 28 MPa, the temperature to 38°C, and the extraction time to 3 h. After extraction, collect the extract. The entrainer is composed of propylene glycol, anhydrous ethanol, and deionized water in a mass ratio of 4:18:72, and the mass ratio of the mixed powder to the entrainer is 1:1.5.

[0053] (3) Add a 28% carboxymethyl-β-cyclodextrin solution to a mixture of 18 parts eugenol and 10 parts thymol. Stir at 25 rpm for 18 min to form a suspension. Ultrasonic treatment at 40 kHz and 55 °C for 1.5 h to obtain an ultrasonic mixture. After standing for 9 h, centrifuge at 9000 rpm for 18 min. Collect the supernatant and dry it at a vacuum of -0.05 MPa to -0.08 MPa and a drying temperature of 45 °C to constant weight to obtain a white powdery inclusion complex.

[0054] (4) Add 14 parts of lecithin, 4 parts of Tween 80, 0.6 parts of disodium pyrophosphate and 25 parts of deionized water to the extract prepared in step (2), heat to 35°C, stir at 25 rpm for 18 min, and slowly add the white powdery inclusion complex prepared in step 4 under stirring conditions. After the addition is complete, continue stirring for 12 min, and then place it in a high-speed homogenizer. Start the homogenizer at a speed of 2500 rpm and homogenize for 8 min. Then increase the homogenizer speed to 6000 rpm and continue homogenizing for 4 min. Then increase the homogenizer speed to 9500 rpm and continue homogenizing for 25 min to obtain a nanoemulsion.

[0055] (5) Heat the nanoemulsion at 25 rpm to 40°C, add 10 parts of gelatin and 6 parts of propylene glycol, continue stirring for 2.5 h under heat preservation conditions, and cool to room temperature to obtain plant compound essential oil.

[0056] The number of components used in the preparation process is based on parts by weight.

[0057] Comparative Example 1

[0058] Compared with Example 1, eugenol and thymol were not added with carboxymethyl-β-cyclodextrin but were added directly with the extract in step (4), while the remaining steps were the same as in Example 1.

[0059] Comparative Example 2

[0060] Compared with Example 1, in step (4) when preparing the inclusion complex, hydroxypropyl-β-cyclodextrin was used instead of carboxymethyl-β-cyclodextrin to include eugenol and thymol, and the remaining steps were the same as in Example 1.

[0061] Comparative Example 3

[0062] Compared with Example 1, glycerol is used instead of propylene glycol in step (5), and the remaining steps are the same as in Example 1.

[0063] Antioxidant and antibacterial properties tests of various plant-based compound essential oils:

[0064] (1) The plant compound essential oils prepared in Example 1 and each comparative example were tested using the DPPH free radical scavenging method. The specific operation steps are as follows:

[0065] DPPH solution: Prepare a 0.1 mM DPPH solution with anhydrous ethanol (store away from light).

[0066] Essential oil sample: Dissolve the essential oil in ethanol to prepare a sample solution of 1 mg / mL.

[0067] Reaction: Take 0.1 mL of sample solution + 2 mL of DPPH solution, mix well and react in the dark for 30 min.

[0068] Detection: Using ethanol as a blank control, the absorbance at 517 nm was measured (A). 样品 Simultaneously, the absorbance of "sample + ethanol" (A0, excluding interference from the sample's own color) and "DPPH + ethanol" (Acontrol) was measured.

[0069] Calculate the clearance rate:

[0070] (2) The long-lasting antibacterial effect of various plant compound essential oils was tested using the filter paper method. The diameter of the inhibition zone was used to reflect the antibacterial effect of the essential oils. The test bacteria were *Botrytis cinerea* and *Penicillium expansum*.

[0071] Sterile filter paper discs with a diameter of 6 mm were soaked in essential oil ethanol solutions of different concentrations (final concentration containing 2% ethanol), drained, and then affixed to the inoculation suspension (10). 6 PDA plates (CFU / mL) were incubated at 25°C for 72 h, and the diameter of the inhibition zone was measured. Each group was repeated three times. The results of antioxidant and antibacterial properties are shown in Table 1.

[0072] Table 1:

[0073] It can be seen that the DPPH clearance rate of each group of plant compound essential oils reached over 90%. However, due to the differences in the release mechanism of the active ingredients in the essential oils, the antibacterial and bacteriostatic effects of each group of essential oils showed significant differences.

[0074] Freshly picked strawberries were divided into 6 groups. Five groups were sprayed with the same amount of preservative oil as in Example 1 and the comparative proportions. The remaining group was sprayed with an equal amount of water. The strawberries were then refrigerated at 4°C. After 10 days, the mold, moisture loss, and hardness of the strawberries were observed. The results are shown in Table 1.

[0075] Table 1:

[0076] It can be seen that in Comparative Example 1, without the use of carboxymethyl-β-cyclodextrin for pre-encapsulation, the effective preservative components relied solely on liposome loading, failing to achieve a gradient release. While the effective components were rapidly released in the early stages of preservation, resulting in significantly superior preservation compared to other examples, the preservation effect declined noticeably in the later stages, failing to achieve long-term preservation. In Comparative Example 2, hydroxypropyl-β-cyclodextrin was used instead of carboxymethyl-β-cyclodextrin. Due to differences in the hydrophilicity of the groups, the synergistic effect with liposomes was not significant, leading to a significant decrease in overall preservation effect compared to Example 1. The unsatisfactory preservation effect of Comparative Example 3 may be due to the poor performance of the antibacterial film structure.

[0077] Furthermore, the products of Example 1 and each comparative example were sprayed onto the surface of bananas and placed at 25°C for 28 days. The inhibitory effect on interphase ripening was then tested. The results are shown in Table 2.

[0078] Table 2:

[0079] To investigate the effect of extracts obtained under different entrainer conditions on the preservation performance of the final preservation essential oil, extracts obtained under different entrainer conditions with the same amount of entrainer were used in the subsequent preparation of preservation essential oil for strawberry preservation tests. The same batch of strawberries was divided into multiple groups, and each group was sprayed with preservation essential oil corresponding to different entrainers. In addition, the antioxidant properties of the corresponding essential oils in each group were further tested. The results are shown in Table 3.

[0080] Table 3:

[0081] In the table above, the "ethanol + acetone + deionized water" group uses acetone to replace propylene glycol in an equal amount. It can be seen that the use of a composite of ethanol + propylene glycol + deionized water as an entrainer in this invention results in a superior overall preservation effect of the extracted active ingredients. The absence of any one of these components leads to a decrease in the performance of the extracted active ingredients, and a significant reduction in their antioxidant effect.

[0082] Example 2

[0083] A method for preparing a plant-based compound essential oil includes the following steps:

[0084] (1) Take lemons, wash them clean, cut them into slices with a thickness of about 0.3 to 0.5 cm, lower the temperature to -18°C at a rate of 5°C / min, keep it for 8 hours, after qualitative analysis, vacuum to -0.05 to -0.08 MPa, raise the temperature to -8°C at a rate of 3°C / min, keep it for 3 hours, then raise the temperature to 15°C within 2 hours and keep it for 3 hours, then raise the temperature to 30°C within 30 minutes and keep it for 6 hours to obtain dried lemon slices. Mix 10 parts of dried lemon slices, 5 parts of mint, and 5 parts of eagle tea and grind them. Grind them through a 12-mesh sieve to obtain mixed powder.

[0085] (2) Place the mixed powder in the extraction vessel of a supercritical carbon dioxide extractor, add the entrainer, set the carbon dioxide flow rate to 12 kg / h, the pressure to 30 MPa, the temperature to 35°C, and the extraction time to 4 h. After extraction, collect the extract. The entrainer is composed of propylene glycol, anhydrous ethanol, and deionized water in a mass ratio of 3:15:70, and the mass ratio of the mixed powder to the entrainer is 1:1.

[0086] (3) Add a 30% carboxymethyl-β-cyclodextrin solution to a mixture of 15 parts eugenol and 10 parts thymol. Stir at 20 rpm for 20 min to form a suspension. Ultrasonic treatment at 35 kHz and 60 °C for 2 h to obtain an ultrasonic mixture. After standing for 10 h, centrifuge at 8000 rpm for 20 min. Collect the supernatant and dry it at a vacuum of -0.05 MPa to -0.08 MPa and a drying temperature of 40 °C to constant weight to obtain a white powdery inclusion complex.

[0087] (4) Add 12 parts of lecithin, 3 parts of Tween 80, 0.5 parts of disodium pyrophosphate and 20 parts of deionized water to the extract prepared in step (2), heat to 30°C, stir at 20 rpm for 20 min, and slowly add the white powdery inclusion complex prepared in step 4 under stirring conditions. After the addition is complete, continue stirring for 10 min, and then place it in a high-speed homogenizer. Start the homogenizer at a speed of 2000 rpm and homogenize for 5 min. Then increase the homogenizer speed to 5000 rpm and continue homogenizing for 3 min. Then increase the homogenizer speed to 9000 rpm and continue homogenizing for 20 min to obtain a nanoemulsion.

[0088] (5) Heat the nanoemulsion at 20 rpm to 40°C, add 10 parts of gelatin and 5 parts of propylene glycol, continue stirring for 2 hours under heat preservation conditions, and cool to room temperature to obtain plant compound essential oil.

[0089] Example 3

[0090] A method for preparing a plant-based compound essential oil includes the following steps:

[0091] (1) Take lemons, wash them clean, cut them into slices with a thickness of about 0.3 to 0.5 cm, lower the temperature to -22°C at a cooling rate of 7°C / min, keep it for 6 hours, after qualitative analysis, vacuum to -0.05 to -0.08 MPa, raise the temperature to -12°C at a rate of 5°C / min, keep it for 2 hours, then raise the temperature to 12°C within 1 hour and keep it for 5 hours, then raise the temperature to 25°C within 60 minutes and keep it for 8 hours to obtain dried lemon slices. Mix 15 parts of dried lemon slices, 8 parts of mint and 8 parts of eagle tea and grind them. Grind them through a 12-mesh sieve to obtain mixed powder.

[0092] (2) Place the mixed powder in the extraction vessel of a supercritical carbon dioxide extractor, add the entrainer, set the carbon dioxide flow rate to 15 kg / h, the pressure to 25 MPa, the temperature to 40°C, and the extraction time to 2 h. After the extraction is completed, collect the extract. The entrainer is composed of propylene glycol, anhydrous ethanol, and deionized water in a mass ratio of 5:20:75, and the mass ratio of the mixed powder to the entrainer is 1:2.

[0093] (3) Add a 25% carboxymethyl-β-cyclodextrin solution to a mixture of 20 parts eugenol and 12 parts thymol. Stir at 30 rpm for 15 min to form a suspension. Ultrasonic treatment at 40 kHz and 50 °C for 3 h to obtain an ultrasonic mixture. After standing for 8 h, centrifuge at 10000 rpm for 15 min. Collect the supernatant and dry it at a vacuum of -0.05 MPa to -0.08 MPa and a drying temperature of 45 °C to constant weight to obtain a white powdery inclusion complex.

[0094] (4) Add 15 parts of lecithin, 5 parts of Tween 80, 0.7 parts of disodium pyrophosphate, and 30 parts of deionized water to the extract prepared in step (2). Heat to 40°C and stir at 30 rpm for 15 min. Under stirring conditions, slowly add the white powdery inclusion complex prepared in step 4. After the addition is complete, continue stirring for 10-15 min. Then place it in a high-speed homogenizer. Start the homogenizer at 3000 rpm and homogenize for 10 min. Then increase the homogenizer speed to 7000 rpm and continue homogenizing for 5 min. Then increase the homogenizer speed to 10000 rpm and continue homogenizing for 30 min to obtain a nanoemulsion.

[0095] (5) Heat the nanoemulsion at 30 rpm to 45°C, add 12 parts of gelatin and 7 parts of propylene glycol, continue stirring for 3 hours under heat preservation conditions, and cool to room temperature to obtain plant compound essential oil.

Claims

1. A method for preparing a plant-based compound essential oil, characterized in that, Includes the following steps: (1) Take lemon slices and freeze-dry them into dried lemon slices. Mix the dried lemon slices, mint and eagle tea and grind them into a mixed powder. (2) Place the mixed powder in a supercritical carbon dioxide extractor for extraction and collect the extract; (3) Add carboxymethyl-β-cyclodextrin solution dropwise to the mixture of eugenol and thymol, stir to form a suspension, sonicate to obtain an ultrasonic mixture, centrifuge to collect the supernatant, and dry to obtain a white powdery inclusion complex. (4) Add lecithin, Tween 80, disodium pyrophosphate and deionized water to the extract prepared in step (2), heat and stir, and then add the inclusion complex from step (3). Homogenize to obtain nanoemulsion. (5) Add gelatin and propylene glycol to the nanoemulsion, heat and keep warm, and then cool to obtain plant compound essential oil.

2. The method for preparing a plant-based compound essential oil as described in claim 1, characterized in that: Based on weight, the amounts of each component used in the preparation process are as follows: eugenol 15-20 parts, thymol 10-12 parts, lemon 10-15 parts, peppermint 5-8 parts, eagle tea 5-8 parts, carboxymethyl-β-cyclodextrin 50-55 parts, gelatin 10-12 parts, propylene glycol 5-7 parts, Tween 80 3-5 parts, disodium pyrophosphate 0.5-0.7 parts, lecithin 12-15 parts, and deionized water 20-30 parts.

3. A method for preparing a plant-based compound essential oil as described in claim 1 or 2, characterized in that: The extraction in step (2) uses propylene glycol, anhydrous ethanol and deionized water as entrainers, with a carbon dioxide flow rate of 12-15 kg / h, a pressure of 25-30 MPa, a temperature of 35-40°C and an extraction time of 2-4 h.

4. The method for preparing a plant-based compound essential oil as described in claim 3, characterized in that: The mass ratio of propylene glycol, anhydrous ethanol, and deionized water in the entrainer is 3-5:15-20:70-75, and the mass ratio of the entrainer to the mixed powder is 1-2:

1.

5. A method for preparing a plant-based compound essential oil as described in any one of claims 1-4, characterized in that: The carboxymethyl-β-cyclodextrin solution in step (3) is obtained by mixing carboxymethyl-β-cyclodextrin and deionized water at a mass ratio of 1:10-15 and stirring and heating at 20-30 rpm to 50-60°C.

6. The method for preparing a plant-based compound essential oil as described in claim 5, characterized in that: In step (3), the ultrasonic treatment frequency is 35-40 kHz, the temperature is 50-60 ℃, and the ultrasonic treatment lasts for 2-3 hours to obtain an ultrasonic mixture.

7. A method for preparing a plant-based compound essential oil according to any one of claims 1-6, characterized in that: In step (4), homogenization is started at a homogenization speed of 2000-3000 rpm. After homogenizing for 5-10 minutes, the homogenization speed is increased to 5000-7000 rpm and homogenization continues for 3-5 minutes. Then, the homogenization speed is further increased to 9000-10000 rpm and homogenization continues for 20-30 minutes to obtain a nanoemulsion.

8. The method for preparing a plant-based compound essential oil as described in claim 7, characterized in that: In step (5), the heating and heat preservation temperature is 40-45℃. During the heat preservation process, the mixture is stirred at 20-30 rpm for 2-3 hours, and then naturally cooled to room temperature.

9. A method for preparing a plant-based compound essential oil, characterized in that, Includes the following steps: (1) Take lemons, wash them clean, and cut them into slices with a thickness of about 0.3 to 0.5 cm. Cool them down to -18 to -22°C at a rate of 5 to 7°C / min and keep them for 6 to 8 hours. After qualitative analysis, vacuum them to -0.05 to -0.08 MPa and heat them up to -8 to -12°C at a rate of 3 to 5°C / min. Keep them for 2 to 3 hours. Then heat them up to 12 to 15°C within 1 to 2 hours and keep them for 3 to 5 hours. Then heat them up to 25 to 30°C within 30 to 60 minutes and keep them for 6 to 8 hours to obtain dried lemon slices. Mix the dried lemon slices, mint and eagle tea together and grind them. Grind them through a 12-mesh sieve to obtain mixed powder. (2) Place the mixed powder in the extraction vessel of a supercritical carbon dioxide extractor, add the entrainer, set the carbon dioxide flow rate to 12-15 kg / h, the pressure to 25-30 MPa, the temperature to 35-40℃, and the extraction time to 2-4 h. After extraction, collect the extract. The entrainer is composed of propylene glycol, anhydrous ethanol, and deionized water in a mass ratio of 3-5:15-20:70-75, and the mass ratio of the mixed powder to the entrainer is 1:1-2. (3) Add carboxymethyl-β-cyclodextrin solution dropwise to the mixture of eugenol and thymol, stir at 20-30 rpm for 15-20 min to form a suspension, sonicate at 35-40 kHz and 50-60 ℃ for 2-3 h to obtain an ultrasonic mixture, let stand for 8-10 h, centrifuge at 8000-10000 rpm for 15-20 min, collect the supernatant, and dry the supernatant at a vacuum of -0.05 MPa to -0.08 MPa and a drying temperature of 40-45 ℃ to constant weight to obtain a white powdery inclusion complex; (4) Add lecithin, Tween 80, disodium pyrophosphate and deionized water to the extract prepared in step (2), heat to 30-40°C, stir at 20-30 rpm for 15-20 min, and slowly add the white powder inclusion complex prepared in step 4 under stirring conditions. After the addition is complete, continue stirring for 10-15 min, and then place it in a high-speed homogenizer. First, start the homogenization speed at 2000-3000 rpm, homogenize for 5-10 min, then increase the homogenization speed to 5000-7000 rpm, continue homogenizing for 3-5 min, then increase the homogenization speed to 9000-10000 rpm, and continue homogenizing for 20-30 min to obtain a nanoemulsion. (5) Heat the nanoemulsion at 20-30 rpm to 40-45°C, add gelatin and propylene glycol, continue stirring for 2-3 hours under heat preservation conditions, and cool to room temperature to obtain plant compound essential oil; The components used in the preparation process, by weight, are: eugenol 15-20 parts, thymol 10-12 parts, lemon 10-15 parts, peppermint 5-8 parts, eagle tea 5-8 parts, carboxymethyl-β-cyclodextrin 50-55 parts, gelatin 10-12 parts, propylene glycol 5-7 parts, Tween 80 3-5 parts, disodium pyrophosphate 0.5-0.7 parts, lecithin 12-15 parts, and deionized water 20-30 parts.

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