A natural surfactant, a preparation method thereof and an application thereof in preparing an emulsion by microfluidic emulsification

Abstract

The present invention belongs to the technical field of natural surfactants, and provides a natural surfactant and a preparation method thereof. The natural surfactant comprises the following components by mass: 15-20 parts of tea saponin, 5-10 parts of tea polyphenols, and 5-10 parts of tea polysaccharide. This natural surfactant can significantly reduce the interfacial tension between the oil and water phases. The present invention also provides an application of the above natural surfactant in the preparation of emulsions, and a microfluidic emulsification device is combined during the emulsion preparation process to achieve a good emulsification effect on the oil phase.

Description

Technical Field

[0001] The present invention belongs to the technical field of surfactants, and particularly relates to a natural surfactant from camellia seeds, a preparation method thereof, and an application thereof in the preparation of emulsions by microfluidic emulsification. Background Art

[0002] Camellia is also known as the tea seed tree and belongs to the Camellia family. It has a wide planting area and rich cultivation experience in China and is one of the important woody oil crops in the 21st century. In recent years, it has been a research hotspot and is favored by many scholars. The camellia outer shell, camellia seed shell, camellia seed kernel, and camellia seed meal after oil extraction all contain a large amount of bioactive substances, including tea oil, tea saponin, tea polyphenols, tea polysaccharides, plant proteins, tannins, caffeine, etc., which have high utilization value. Tea saponin is a natural non-ionic surfactant and also has the functions of sterilization, anti-inflammatory, and antipruritic. Tea saponin also has certain hemolytic activity and insecticidal and antibacterial activities and has been developed and widely used as a biological pesticide; when applied to the human body, tea saponin has a mild nature and no irritation to the skin. Combining its emulsifying performance, foaming ability, and detergency, it is an excellent natural emulsifier. Tea polysaccharides contain many functional factors beneficial to the human body and participate in the body's immune regulation, cell recognition, and material transport between cells, and have the effects of anticoagulation and repair of metabolic disorders. Tea polyphenols are one of the important pharmacodynamic components in camellia seeds. Tea polyphenols have pharmacodynamic effects such as antioxidant, anti-tumor and anti-cancer, antiviral, and antibacterial, and are a natural plant medicinal component. Due to the obvious free radical scavenging ability of tea polyphenols, adding tea polyphenols to tea oil can significantly improve the antioxidant ability of tea oil.

[0003] Microfluidic technology refers to the manipulation of fluid systems at a microscale and is an emerging interdisciplinary subject involving chemistry, fluid physics, microelectronics, new materials, and biomedical engineering. The traditional emulsification technology for preparing suspended microdroplets generally uses a high-speed shearing method, placing oil, water, surfactant, and thickener together in a container and using a high-shear emulsifier for emulsification. Compared with traditional technologies, the microfluidic droplet preparation technology has significant advantages. Microfluidics has low energy consumption, and the droplet size prepared by it is uniform and controllable, and batch production can be achieved through parallel amplification of microfluidic devices. Therefore, using microfluidic technology to prepare emulsions has broad application advantages and prospects.

[0004] Natural vegetable oils such as camellia oil, olive oil, apricot kernel oil, wheat germ oil, etc. often contain a variety of active ingredients beneficial to the skin and are excellent raw materials for cosmetic efficacy. However, natural vegetable oils contain a large amount of unsaturated fatty acids and are extremely susceptible to oxidation and rancidity and the generation of harmful substances such as aldehydes and ketones under the influence of air, light, water, etc. in the environment, which limits the product form and popularization and application of natural vegetable oils. An emulsion is a dispersion system formed by combining two immiscible solutions, usually one solution dispersed in another solution in the form of small droplets. By emulsifying natural vegetable oils, it is possible to better carry and protect lipophilic active ingredients. Therefore, it is very necessary to develop a safe and effective surfactant for the emulsification of natural vegetable oils. Summary of the Invention

[0005] The present invention provides a natural surfactant and a preparation method thereof, and applies it to the preparation of natural vegetable oil emulsion by microfluidic emulsification to improve its bioavailability and environmental tolerance.

[0006] The technical solution of the present invention is as follows: In the first aspect, a natural surfactant is provided, which includes the following components by mass: 15-20 parts of tea saponin, 5-10 parts of tea polyphenols, and 5-10 parts of tea polysaccharides.

[0007] In the second aspect, a preparation method of the above natural surfactant is provided, including the following steps:

[0008] (1) Take defatted oil-tea seeds and crush them until the particle size of the oil-tea seeds is 60±10 mesh, and then dry them.

[0009] (2) Add 70% ethanol to the defatted oil-tea seed powder obtained by crushing the above defatted oil-tea seeds, adjust the pH value to 9±0.5 with an aqueous NaOH solution, ultrasonically extract for 3±0.5 h and then concentrate and separate to obtain a crude oil-tea seed extract.

[0010] (3) After loading the macroporous adsorption resin into the chromatography column, elute with ethanol solutions of different concentration gradients, separate and collect the eluents of tea saponin, tea polysaccharide and tea polyphenols, and concentrate and dry the eluents eluting tea saponin, tea polysaccharide and tea polyphenols respectively.

[0011] (4) Mix and compound the tea saponin, tea polysaccharide and tea polyphenols obtained by concentration and drying in step (3) according to mass to prepare a natural surfactant of oil-tea seeds.

[0012] Preferably, in step (3), the macroporous adsorption resin is DMl30.

[0013] In a third aspect, there is provided an application of the above natural surfactant or a natural surfactant prepared by the above preparation method in the preparation of an emulsion by microfluidic emulsification.

[0014] Preferably, the natural surfactant is used to prepare a natural vegetable oil emulsion, and its preparation method includes the following steps: dissolving the natural surfactant in a buffer aqueous solution as the aqueous phase, using natural vegetable oil as the oil phase, and then mixing and treating the aqueous phase and the oil phase through a microfluidic emulsification device to prepare a natural vegetable oil emulsion.

[0015] Preferably, the method for preparing the natural vegetable oil emulsion includes the following steps:

[0016] (1) Preparation of the aqueous phase: Dissolve the natural surfactant using a phosphate buffer solution, continuously stir at room temperature for 2 ± 0.5 h, and place it in a refrigerator at 4 ± 1 °C overnight as the aqueous phase;

[0017] (2) Preparation of the oil phase: Take 10% of natural vegetable oil relative to the aqueous phase as the oil phase;

[0018] (3) Preparation of the emulsion: Mix and treat the above aqueous phase and oil phase through the microfluidic emulsification device to prepare a natural vegetable oil emulsion.

[0019] Preferably, the microfluidic emulsification device includes a first syringe pump and a first syringe connected to the first syringe pump, a second syringe pump and a second syringe connected to the second syringe pump, as well as a microfluidic chip and a liquid storage tank; the first syringe and the second syringe are respectively used to inject the oil phase and the aqueous phase, the outlets of the first syringe and the second syringe are respectively connected to the first liquid inlet and the second liquid inlet of the microfluidic chip through pipelines, and the liquid outlet of the microfluidic chip is connected to the liquid storage tank through a pipeline.

[0020] Preferably, the first syringe and the second syringe are respectively connected to the microfluidic chip through microfluidic pipelines, and the liquid outlet of the microfluidic chip is connected to the liquid storage tank through a microfluidic pipeline. The emulsion prepared by the microfluidic emulsification device is an oil-in-water or water-in-oil emulsion.

[0021] Preferably, when mixing the aqueous phase and the oil phase using the microfluidic emulsification device, first push the first syringe to fill the microfluidic chip with the oil phase, and then slowly push the first syringe and the second syringe simultaneously to generate an emulsion in the microfluidic chip, which is then collected by the liquid storage tank.

[0022] In a fourth aspect, the present invention also provides a natural vegetable oil emulsion prepared by the above preparation method.

[0023] Compared with the prior art, the present invention has the following enhanced technical effects:

[0024] (1) The present invention uses camellia seeds as raw materials, and the extracted compound of camellia seeds is used as a natural surfactant for the preparation of emulsions, which improves the utilization value of camellia seeds. The prepared natural surfactant is plant-extracted and has high safety.

[0025] (2) The present invention uses the extracted compound of camellia seeds as a natural surfactant, which can significantly reduce the interfacial tension between two phases, promote emulsification, and reduce the overall usage amount of emulsifiers.

[0026] (3) The present invention uses the extracted compound of camellia seeds as a natural surfactant and combines it with a customized microfluidic emulsification device, which has a good emulsification effect on the emulsification of natural vegetable oils. Description of the Drawings

[0027] Figure 1 is the average particle size of the natural vegetable oil emulsion prepared in Example 4.

[0028] Figure 2 is the polydispersity coefficient of the natural vegetable oil emulsion prepared in Example 4

[0029] Figure 3 is the average particle size of the natural vegetable oil emulsion prepared in Example 5.

[0030] Figure 4 is the polydispersity coefficient of the natural vegetable oil emulsion prepared in Example 5.

[0031] Figure 5 is the average particle size of the natural vegetable oil emulsion prepared in Example 6.

[0032] Figure 6 is the polydispersity coefficient of the natural vegetable oil emulsion prepared in Example 6.

[0033] Figure 7 is the hemolysis rate of the emulsions prepared with different emulsifiers in Example 7.

[0034] Figure 8 is a schematic diagram of the microfluidic emulsification device described in the present invention; wherein, 1, the first syringe pump, 2, the second syringe pump, 3, the first syringe, 4, the second syringe, 5, the microfluidic chip, 5-1, the first liquid inlet, 5-2, the second liquid inlet, 5-3, the liquid outlet, 6, the liquid storage tank, 7, the microfluidic conduit. Detailed Embodiments

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] Example 1 Preparation of Natural Surfactant

[0037] Using 70% ethanol as the extraction solvent, bioactive substances were extracted from camellia seeds by ultrasonic-assisted method, and macroporous adsorption resin was used to separate and purify the crude extract of camellia seeds to obtain tea saponin, tea polysaccharide, and tea polyphenols.

[0038] The specific steps are as follows:

[0039] (1) Raw material pretreatment: Take 20 g of defatted camellia seeds and crush them until the particle size of the camellia seeds is 60 mesh, and then dry them.

[0040] (2) Ultrasonic extraction: Add 250 ml of 70% ethanol to the dried camellia seed powder obtained in step (1), and adjust the pH value to 9 with NaOH aqueous solution. After ultrasonic extraction for 3 h, concentrate and separate to obtain the crude extract of camellia seeds.

[0041] (3) Separation and purification: After loading DMI30 macroporous adsorption resin into the chromatography column, elute with 30% ethanol, 50% ethanol, and 60% ethanol, and finally concentrate and dry the eluents of tea saponin, tea polysaccharide, and tea polyphenols.

[0042] (4) Mixing and compounding: Mix and compound the tea saponin, tea polysaccharide, and tea polyphenols extracted, separated, and dried from camellia seeds by mass parts. The obtained camellia seed extraction compound is the natural surfactant of camellia seeds, and its compounding ratio is shown in Table 1 below.

[0043] Table 1 Composition list of camellia seed extraction compound

[0044]

[0045]

[0046] Example 2 Comparison of the surface tension of natural surfactant and conventional surfactant aqueous solutions

[0047] Respectively test the surface tension of the aqueous solution of the camellia seed extraction compound prepared in Example 1 and the aqueous solutions of other conventional surfactants.

[0048] The specific steps are as follows: The natural surfactant aqueous solution obtained by dissolving the camellia seed extract compound prepared in Example 1 in distilled water, and the aqueous solutions of alkylphenol polyoxyethylene ether (OP-10), sodium lauryl alcohol polyoxyethylene ether sulfate (AES), and fatty acid diethanolamide (6501) are respectively used to measure the surface tension at 25 °C with a full-automatic surface tension measuring instrument. The measurement results are shown in Table 2.

[0049] Table 2 Comparison of surface activities of camellia seed extract compound and conventional surfactants

[0050]

[0051] According to the test results in Table 1, it can be seen that the above-mentioned camellia seed extract compounds have a higher effect on reducing the surface tension of water than the conventional surfactants AES and 6501. In particular, the camellia seed extract compound 3 is a good natural surfactant. The camellia seed extract compound in the subsequent examples is preferably the camellia seed extract compound 3.

[0052] Example 3 Surface tension of natural surfactant aqueous solutions with different concentrations at different pH values

[0053] Dissolve the camellia seed extract compound 3 prepared in Example 1 in distilled water to obtain a natural surfactant aqueous solution, adjust the pH value of the natural surfactant aqueous solution with acid and alkali, and measure the surface tension of the natural surfactant aqueous solution with different concentrations and different pH values. It should be noted that the acid and alkali used can be 5M or 1M hydrochloric acid and sodium hydroxide aqueous solutions respectively. In this example, 5 mol / L hydrochloric acid and sodium hydroxide aqueous solutions are preferably used. The measurement results of this example are shown in Table 3.

[0054] Table 3 Surface tension of camellia seed extract compound aqueous solutions with different concentrations at different pH values

[0055]

[0056]

[0057] According to the test results in Table 2, it can be seen that increasing the acidity enhances the ability of the camellia seed extract compound to reduce the surface tension of water, while adding alkali weakens its ability to reduce the surface tension of water. However, with the increase in the concentration of the camellia seed extract compound, the change in the solution pH has no obvious effect on the ability to reduce the surface tension of water. Therefore, when the camellia seed extract compound is used as a surfactant, it can be unaffected within a certain range of acidity and alkalinity.

[0058] Example 4 Test the emulsifying ability and stability of the camellia seed extract compound for common oils and fats

[0059] Using the camellia seed extract complex 3 prepared in Example 1 as a natural surfactant to prepare a natural vegetable oil emulsion, and comparing it with the natural vegetable oil emulsion prepared using tea saponin as an emulsifier, the preparation method includes the following steps:

[0060] (1) Preparation of the aqueous phase: Dissolve the camellia seed extract complex and tea saponin respectively with phosphate buffer solution (0.04 mol / L, pH = 7) and dilute them to different concentrations (0.5 wt%, 1.0 wt%, 2.0 wt%, 3.0 wt%, 5.0 wt%). Continuously stir at room temperature for 2 h, and place it in a 4°C refrigerator overnight to obtain the aqueous phase.

[0061] (2) Preparation of the oil phase: Take 10% of the volume of the aqueous phase of camellia oil as the oil phase.

[0062] (3) Preparation of the emulsion: Perform high-pressure homogenization treatment on the above-prepared aqueous phase and oil phase. Set the homogenization pressure of the high-pressure homogenizer to 100 MPa and the number of homogenization times to 7 times to obtain a natural vegetable oil emulsion. Measure the average particle size and polydispersity index (PDI) of the emulsion, and the results are as Figure 1 and Figure 2 shown.

[0063] According to Figure 1 and Figure 2 the test results, it can be known that the natural vegetable oil emulsion prepared using the camellia seed extract complex has good properties. Its average particle size is close to or less than 1000 nm, PDI is lower than 0.3, and it shows a dose effect with the increase of the concentration of the camellia seed extract complex; and combined with Figure 1 and Figure 2 it can be seen that the natural vegetable oil emulsion prepared using the camellia seed extract complex has superior emulsifying performance to the natural vegetable oil emulsion prepared using tea saponin with the same mass fraction.

[0064] Example 5 tests the emulsifying performance of the camellia seed extract complex combined with a conventional surfactant to form a composite emulsifier

[0065] Using the composite emulsifier prepared by compounding the camellia seed extract complex 3 prepared in Example 1 and sodium dodecyl benzene sulfonate to prepare a natural vegetable oil emulsion, including the following steps:

[0066] (1) Preparation of the aqueous phase: Compound different mass ratios of the camellia seed extract complex and sodium dodecyl benzene sulfonate so that the mass content of the camellia seed extract complex is 0%, 25%, 50%, 75%, 100% respectively, and dissolve them in phosphate buffer solution (0.04 mol / L, pH = 7) to finally form a 3.0 wt% composite emulsifier. Continuously stir at room temperature for 2 h, and place it in a 4°C refrigerator overnight to obtain the aqueous phase.

[0067] (2) Preparation of the oil phase: Take 10% of the volume of the aqueous phase of camellia oil as the oil phase.

[0068] (3) Preparation of emulsion: The aqueous phase and oil phase prepared above were subjected to high-pressure homogenization treatment. The homogenization pressure of the high-pressure homogenizer was set at 100 MPa, and the number of homogenization times was 7 times to obtain a natural vegetable oil emulsion. The average particle size and PDI of the emulsion were measured, and the results are as Figure 3 and Figure 4 shown.

[0069] According to Figure 3 and Figure 4 the test results, the composite emulsifier prepared by compounding the camellia seed extract complex with sodium dodecylbenzenesulfonate has significantly higher emulsifying performance than the single-component emulsifier. Considering the average particle size and polydispersity coefficient of the emulsion comprehensively, when the mass ratio of the camellia seed extract complex reaches 50%, the emulsifying effect is the best. The above results indicate that the camellia seed extract complex can significantly reduce the dosage of the overall emulsifier.

[0070] Example 6: A microfluidic emulsification device was used to prepare a natural vegetable oil emulsion

[0071] Using the camellia seed extract complex 3 prepared in Example 1 as a natural surfactant to prepare a natural vegetable oil emulsion, the preparation method includes the following steps:

[0072] (1) Preparation of aqueous phase: The camellia seed extract complex was dissolved and diluted to different concentrations (0.5 wt%, 1.0 wt%, 2.0 wt%, 3.0 wt%, 5.0 wt%) with phosphate buffer solution (0.04 mol / L, pH = 7), continuously stirred at room temperature for 2 h, and placed in a 4°C refrigerator overnight as the aqueous phase.

[0073] (2) Preparation of oil phase: Taking 10% of the volume of camellia oil relative to the aqueous phase as the oil phase.

[0074] (3) Preparation of emulsion: The aqueous phase and oil phase prepared above were mixed and emulsified through a microfluidic device to obtain a natural vegetable oil emulsion.

[0075] As Figure 8 shown, in this example, the microfluidic device includes a first syringe pump 1 and a first syringe 3 connected to the first syringe pump 1, a second syringe pump 2 and a second syringe 4 connected to the second syringe pump 2, a microfluidic chip 5 and a liquid storage tank 6. Among them, the first syringe 3 extracts the oil phase through the first syringe pump 1, the second syringe 4 extracts the aqueous phase through the second syringe pump 2, the first syringe 3 and the second syringe 4 are respectively connected to the first liquid inlet 5-1 and the second liquid inlet 5-2 of the microfluidic chip 5 through microfluidic conduits 7, and the liquid outlet 5-3 of the microfluidic chip 5 is connected to the liquid storage tank 6 through a microfluidic conduit.

[0076] In this embodiment, when preparing the emulsion using the above-mentioned microfluidic device, first push the first syringe 3 to fill the microfluidic chip 5 with the oil phase. Then, slowly push the first syringe 3 and the second syringe 4 simultaneously to generate an emulsion in the microfluidic chip 5. After collection by the liquid storage tank 6, the average particle size and PDI of the emulsion are measured, and the measurement results are as Figure 5 and Figure 6 shown.

[0077] According to Figure 5 and Figure 6 the results of Figure 1 and Figure 2 it can be seen that for the natural vegetable oil emulsion prepared using the microfluidic emulsification device, its average droplet size and polydispersity coefficient are significantly lower than those of the emulsion prepared without using the microfluidic device, and its emulsion properties are better.

[0078] Example 7 Hemolytic toxicity evaluation of the emulsion prepared from the complex extract of camellia seeds

[0079] In the present invention, the emulsion prepared has a small particle size, which is beneficial for skin penetration and may enter the blood. Moreover, the saponin contained in the camellia seed extract has certain hemolytic activity. Therefore, its potential hemolytic property is evaluated to investigate the blood safety of the emulsion. In vivo hemolysis (rupture of red blood cells) can lead to anemia, jaundice and other pathological conditions.

[0080] The hemolytic toxicities of the complex emulsifiers formed by saponin and the complex extract of camellia seeds with sodium dodecylbenzenesulfonate, and the emulsion prepared using the microfluidic device in combination with the complex extract of camellia seeds are evaluated respectively.

[0081] According to the principle that the heme released by the rupture of red blood cells has the maximum absorption in the visible light wavelength range, the hemolysis degree of the test solution is detected by spectrophotometry. A 4% red blood cell suspension (v / v, 0.5 mL) and the sample solution are incubated at 37 °C for 6 h, and the supernatant after low-speed centrifugation is collected and the absorbance at 562 nm is measured. Here, the supernatant of the 4% red blood cell suspension (v / v, 0.5 mL) incubated and centrifuged with deionized water is used as the positive control. Calculate the hemolysis rate Hemolysis (%) = A / A 0 × 100, A: the absorbance of the red blood cell solution added with deionized water; A 0 : the absorbance of the red blood cell solution added with the sample solution. The hemolytic toxicity results of the emulsions prepared with emulsifiers of different concentrations are as Figure 7 shown. According to Figure 7 the results of

[0082] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Application of a natural surfactant in the preparation of an emulsion by microfluidic emulsification, characterized in that, the natural surfactant is used to prepare a natural vegetable oil emulsion, and the preparation method comprises the following steps: adding the natural surfactant into a buffer aqueous solution for dissolution to serve as the aqueous phase, using natural vegetable oil as the oil phase, and then mixing and treating the aqueous phase and the oil phase through a microfluidic emulsification device to prepare a natural vegetable oil emulsion; by mass, the natural surfactant consists of the following components: 15-20 parts of tea saponin, 5-10 parts of tea polyphenols, and 10 parts of tea polysaccharide.

2. The application according to claim 1, characterized in that, the preparation method of the natural surfactant comprises the following steps: (1) Take defatted oil-tea seeds and crush them until the particle size of the oil-tea seeds is 60±10 mesh, and then dry them; (2) Add 70% ethanol to the defatted oil-tea seed powder obtained after crushing the defatted oil-tea seeds, and adjust the pH value to 9±0.5 with an NaOH aqueous solution, and perform ultrasonic extraction for 3±0.5 h and then concentrate and separate to obtain a crude extract of oil-tea seeds; (3) After loading the macroporous adsorption resin into the chromatography column, elute it with ethanol solutions of different concentration gradients, separate and collect the elution solutions of tea saponin, tea polysaccharide and tea polyphenols, and concentrate and dry the elution solutions eluting tea saponin, tea polysaccharide and tea polyphenols respectively; (4) Mix and compound the tea saponin, tea polysaccharide and tea polyphenols obtained by concentration and drying in step (3) according to mass parts to prepare a natural surfactant.

3. The application according to claim 2, characterized in that, in step (3), the macroporous adsorption resin is DMl30.

4. The application according to claim 1, characterized in that, the preparation of the natural vegetable oil emulsion comprises the following steps: (1) Preparation of the aqueous phase: Dissolve the natural surfactant with a phosphate buffer solution, continuously stir at room temperature for 2±0.5 h, and place it in a refrigerator at 4±1°C overnight to serve as the aqueous phase; (2) Preparation of the oil phase: Take 10% of the natural vegetable oil relative to the aqueous phase as the oil phase; (3) Preparation of the emulsion: Mix and treat the above aqueous phase and oil phase through the microfluidic emulsification device to prepare a natural vegetable oil emulsion.

5. The application according to claim 1 or 4, characterized in that, the microfluidic emulsification device comprises a first syringe pump and a first syringe connected to the first syringe pump, a second syringe pump and a second syringe connected to the second syringe pump, as well as a microfluidic chip and a liquid storage tank; the first syringe and the second syringe are respectively used for injecting the oil phase and the aqueous phase, the outlets of the first syringe and the second syringe are respectively connected to the first liquid inlet and the second liquid inlet of the microfluidic chip through pipelines, and the liquid outlet of the microfluidic chip is connected to the liquid storage tank through a pipeline.

6. The application according to claim 5, characterized in that, the first syringe and the second syringe are respectively connected to the microfluidic chip through microfluidic pipelines, and the liquid outlet of the microfluidic chip is connected to the liquid storage tank through a microfluidic pipeline.

7. The application according to claim 6, characterized in that, When mixing the aqueous phase and the oil phase using the microfluidic emulsification device, first push the first syringe to fill the microfluidic chip with the oil phase, and then slowly push the first syringe and the second syringe simultaneously to generate an emulsion in the microfluidic chip, which is then collected by the liquid storage tank.

8. A natural vegetable oil emulsion, characterized in that it is prepared by using the preparation method of the natural vegetable oil emulsion in the application described in claim 4.

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