Composite essential oil nanoemulsion as well as preparation method and application thereof

Abstract

The invention relates to an o / w type high-content composite essential oil nanoemulsion and a preparation method and application thereof.The median particle size of the composite essential oil nanoemulsion is not larger than 45 nm, and the composite essential oil nanoemulsion comprises plant essential oil, polyethylene glycol glycerol ricinoleate with the HLB value being 10-14, a cosolvent, water, vitamin E acetate and ethylene diamine tetraacetic acid disodium salt. The plant essential oil is selected from two or more of carvacrol, cinnamyl aldehyde, capsicum oleoresin and thymol. The compound essential oil nanoemulsion solves the key technical problem of high-content load compound nanoemulsion of various plant essential oils, is beneficial to exerting the synergistic effect of different essential oils, and reduces the addition amount of the essential oils while achieving the same physiological function. Besides, the particle size of the composite essential oil nanoemulsion reaches the nanoscale, the composite essential oil nanoemulsion can form homogeneous-phase clear liquid, can be quickly diffused in a waterline or a water environment, is more beneficial to absorption, has the advantages of good stability and long storage life, and is more competitive in practical application.

Description

Technical Field

[0001] The present invention relates to the technical field of nanoemulsion, and particularly relates to an o / w type composite essential oil nanoemulsion, a preparation method thereof and an application thereof. Background Art

[0002] Plant essential oils such as carvacrol, cinnamaldehyde, thymol, etc. have various physiological activities such as antibacterial, antioxidant, immune regulation, etc., and can be used as feed additives in livestock production. However, most of these plant essential oils are single or compound formulations, and there are the following problems in use: First, most plant essential oils have strong volatility, and during the processes of feed processing, storage and transportation, the essential oil components are likely to volatilize and be lost, resulting in a decrease in the content of their active ingredients, thereby affecting their expected physiological activities. Second, the active ingredients in plant essential oils are prone to chemical changes under conditions such as light, high temperature, oxidation, etc., leading to changes in their structures and functions. For example, cinnamaldehyde is easily oxidized under light to form other inactive or less active substances. Third, most plant essential oils are lipophilic substances and are difficult to be uniformly dispersed in the animal digestive tract, resulting in a limited contact area with the digestive tract mucosa, and thus reducing their absorption efficiency. For example, the solubility of carvacrol and thymol in water is low, and they cannot be directly added to the water line. The application scenarios are limited, which is not conducive to on-site use or rapid supplementation, and it is difficult for animals to effectively absorb them. Fourth, due to the large differences in density and polarity between plant essential oils and feed matrices, it is difficult to be uniformly distributed in the feed after direct addition. This will lead to unstable doses of essential oils ingested by animals, affecting the exertion of their physiological effects. For example, during the feed processing process, essential oils may aggregate in some parts of the feed, while there are almost no essential oil components in other parts. Fifth, in order to achieve antibiotic substitution or certain special effects, the addition amount of plant essential oils is often very high, which is not only uneconomical but also has poor palatability.

[0003] Although some researchers have made plant essential oils into emulsion preparations, in the existing emulsion preparations, the particle size of plant essential oils is relatively large, usually in the micron level, which results in poor absorption effects in animals. The relatively large particle size will limit the contact area between essential oil molecules and the digestive tract mucosa, thereby reducing their bioavailability. In addition, the emulsion with a large particle size has poor stability and is prone to stratification and precipitation, further affecting its uniform distribution in the feed and long-term storage.

[0004] Therefore, it is of great practical significance to develop a new type of feed additive that can effectively solve problems such as large particle size of plant essential oils, poor absorption, single or high-content loading of compound formulations, etc. Summary of the Invention

[0005] An object of the present invention is to provide a clear composite essential oil nanoemulsion with a small particle size, good stability and a long shelf life.

[0006] The second object of the present invention is to provide a method for preparing the composite essential oil nanoemulsion as described above.

[0007] The third object of the present invention is to provide an application of the composite essential oil nanoemulsion as described above.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows: On the one hand, the present invention provides a composite essential oil nanoemulsion. Based on the total mass of the composite essential oil nanoemulsion being 100%, the composite essential oil nanoemulsion includes: 15% - 30% of plant essential oil, and the plant essential oil is selected from two or more of carvacrol, cinnamaldehyde, oleoresin capsici, and thymol; 40% - 60% of polyethylene glycol glycerol ricinoleate, and the HLB value of the polyethylene glycol glycerol ricinoleate is 10 - 14; 10% - 30% of co - solvent; 5% - 30% of water; 0.01% - 0.5% of vitamin E acetate; 0 - 0.1% of ethylenediaminetetraacetate, The median particle size of the composite essential oil nanoemulsion is not greater than 45 nm.

[0009] During the extraction process, plant essential oils are usually dispersed in the extraction solvent in the form of droplets, and the particle size of the essential oil droplets is usually between micrometers and several hundred micrometers, with a relatively large particle size. It is difficult to prepare plant essential oil nanoemulsions (usually between 10 nm and 100 nm), especially nanoemulsions with a high content of plant essential oils. The applicant uses polyethylene glycol glycerol ricinoleate with an HLB value of 10 - 14 as an emulsifier, which effectively reduces the oil - water interfacial tension, making it easier for the oil phase and the water phase to form a stable emulsification system. Moreover, it can form an interfacial film with a certain strength and elasticity at the oil - water interface, preventing the aggregation and coalescence of emulsion droplets, and further optimizing the stability and particle size of the nanoemulsion. The applicant also adds co - solvents, vitamin E acetate, etc. Through their synergistic effect with the emulsifier, it can increase the dispersion degree of the emulsifier, assist the emulsifier to better play the role of liquid coating at the oil - water interface, reduce the interfacial tension, reduce oxidative decay, promote the formation of nanoemulsion droplets, and optimize the physicochemical properties of the nanoemulsion, such as particle size distribution, stability, etc.; at the same time, it can also improve the solubility of the oil phase in the water phase, enabling more plant essential oils to be evenly dispersed in the nanoemulsion and increasing the essential oil content in the nanoemulsion. In addition, it can effectively prevent the negative effects caused by low temperature or anti - freeze in cold regions.

[0010] Preferably, the median particle size of the composite essential oil nanoemulsion is 5 nm - 45 nm, such as 5 nm, 15 nm, 30 nm, 35 nm, 40 nm, 45 nm, etc.

[0011] Preferably, the plant essential oil is carvacrol, cinnamaldehyde, oleoresin capsici, and thymol.

[0012] More preferably, the mass content of carvacrol in the compound essential oil nanoemulsion > the mass content of cinnamaldehyde in the compound essential oil nanoemulsion > the mass content of oleoresin capsici in the compound essential oil nanoemulsion > the mass content of thymol in the compound essential oil nanoemulsion.

[0013] In some embodiments, the mass content of carvacrol in the compound essential oil nanoemulsion is 7% - 12%, more preferably 7% - 9%, such as 7%, 7.5%, 8%, 8.5%, 9%.

[0014] In some embodiments, the mass content of cinnamaldehyde in the compound essential oil nanoemulsion is 5% - 10%, more preferably 5% - 7%, such as 5%, 5.5%, 6%, 6.5%, 7%.

[0015] In some embodiments, the mass content of oleoresin capsici in the compound essential oil nanoemulsion is 2% - 5%, more preferably 3% - 5%, such as 3%, 3.5%, 4%, 4.5%, 5%.

[0016] In some embodiments, the mass content of thymol in the compound essential oil nanoemulsion is 1% - 4%, more preferably 1% - 3%, such as 1%, 1.5%, 2%, 2.5%, 3%.

[0017] In some specific and preferred embodiments, based on the total mass of the compound essential oil nanoemulsion being 100%, the compound essential oil nanoemulsion comprises: Carvacrol 7% - 10%, Cinnamaldehyde 5% - 10%, Oleoresin capsici 2% - 5%, Thymol 1% - 4%, Polyethylene glycol glycerol ricinoleate 40% - 60%, Cosolvent 15% - 30%, Water 5% - 30%, Vitamin E acetate 0.01% - 0.2%, Ethylenediaminetetraacetate 0.01 - 0.05%.

[0018] Further, based on the total mass of the compound essential oil nanoemulsion being 100%, the compound essential oil nanoemulsion comprises: Carvacrol 7% - 9%, Cinnamaldehyde 5% - 7%, Oleoresin capsici 3% - 5%, Thymol 1% - 3%, Polyethylene glycol glycerol ricinoleate 45% - 55%, Cosolvent 15% - 25%, Water 5% - 15%, Vitamin E acetate 0.01% - 0.2%, Ethylenediaminetetraacetate 0.01 - 0.05%.

[0019] Preferably, the cosolvent is selected from one or more of polyethylene glycol and propylene glycol.

[0020] Preferably, the ethylenediaminetetraacetate is disodium ethylenediaminetetraacetate.

[0021] Preferably, the water is selected from one or more of purified water, deionized water, and distilled water.

[0022] The second aspect of the present invention provides a method for preparing the composite essential oil nanoemulsion as described above, comprising the following steps: (1) Mix the plant essential oil and vitamin E acetate, and stir evenly to form an oil phase; (2) Mix the oil phase from step (1) with polyethylene glycol glycerol ricinoleate, and stir evenly to form a mixture; (3) Mix the cosolvent and water, and optionally add disodium ethylenediaminetetraacetate, and stir evenly to form an aqueous phase; (4) Mix the mixture from step (2) with the aqueous phase from step (3), and stir evenly to prepare the composite essential oil nanoemulsion.

[0023] The preparation method of the present invention is simple. It only requires simple mechanical stirring to prepare the nanoemulsion, which is easy for large-scale industrial production, has low production costs, and has significant practicality and economy.

[0024] Preferably, the mixing temperatures in steps (1) to (4) are independently selected from 30°C to 60°C, and more preferably from 40°C to 50°C.

[0025] Preferably, the stirring speeds in steps (1) to (4) are independently selected from 1000 r / min to 3000 r / min, and more preferably from 1500 r / min to 2500 r / min.

[0026] The third aspect of the present invention further provides an application of the composite essential oil nanoemulsion as described above, and the application includes adding the composite essential oil nanoemulsion as a feed additive to feed or drinking water.

[0027] Preferably, the addition amount of the composite essential oil nanoemulsion is 50 - 500 g / ton of feed.

[0028] Further preferably, the addition amount of the composite essential oil nanoemulsion is 50-150 g / ton of feed.

[0029] Preferably, the composite essential oil nanoemulsion is diluted and then sprayed onto the feed.

[0030] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The composite essential oil nanoemulsion of the present invention not only has a high essential oil content, but also its particle size can reach the nanometer level, which is more conducive to absorption. At the same time, it also has the advantages of good stability and long shelf life, and can maintain excellent physical and chemical properties during long-term storage and transportation, and is more competitive in practical applications. Description of the Drawings

[0031] Figure 1 It is a physical picture of the composite essential oil nanoemulsion of Example 1. Detailed Embodiments

[0032] The present invention will be further described below in conjunction with the embodiments. However, the present invention is not limited to the following embodiments. The implementation conditions adopted in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0033] Unless otherwise specified, the raw materials involved in the following examples and comparative examples are all commercially available products. Among them, oleoresin capsicum, oil-soluble, Guangdong Tiansheng Food Technology Co., Ltd.; polyethylene glycol, Liaoning Aoke Chemical Co., Ltd., PEG400.

[0034] Example 1: A preparation method of a composite essential oil nanoemulsion, comprising the following steps: (1) Mix 80 parts by mass of carvacrol, 60 parts by mass of cinnamaldehyde, 40 parts by mass of oleoresin capsicum, 20 parts by mass of thymol and 1 part by mass of vitamin E acetate, and stir evenly at 45 °C and a stirring speed of 2000 r / min to prepare an oil phase.

[0035] (2) Add 500 parts by mass of polyethylene glycol glycerol ricinoleate (HLB = 10-14, Nouryon Surface Chemistry AB, Sweden, Blendol 694 and Blendol 688 are compounded according to a mass ratio of 9:1) to the oil phase in step (1), and stir evenly at 45 °C and a stirring speed of 2000 r / min to prepare a mixture.

[0036] (3) Mix 200 parts by mass of polyethylene glycol, 100 parts by mass of purified water and 0.2 part by mass of disodium ethylenediaminetetraacetate, and stir evenly to prepare an aqueous phase.

[0037] (4) Mix the mixture in step (2) and the aqueous phase in step (3), and stir evenly at 45 °C with a stirring speed of 2000 r / min to prepare a nanoemulsion, as Figure 1 shown.

[0038] Example 2: This example is substantially the same as Example 1, except that: in step (3), disodium ethylenediaminetetraacetate is not added.

[0039] Comparative Example 1: This comparative example is substantially the same as Example 1, except that: ① Polyethylene glycol glycerol ricinoleate is not added, that is, the operation in step (2) is not carried out, and the oil phase in step (1) and the aqueous phase in step (3) are directly mixed and stirred evenly.

[0040] ② The amount of purified water in step (3) is 600 parts by mass.

[0041] Comparative Example 2: This comparative example is substantially the same as Example 1, except that: sodium cholate is used to replace polyethylene glycol glycerol ricinoleate in an equal mass.

[0042] Comparative Example 3: This comparative example is substantially the same as Example 1, except that: lysophosphatidylcholine is used to replace polyethylene glycol glycerol ricinoleate in an equal mass.

[0043] Comparative Example 4: This comparative example is substantially the same as Example 1, except that: polyethylene glycol glycerol ricinoleate with HLB = 8.9 (Brij 683, Clariant Sweden AB) is used to replace the polyethylene glycol glycerol ricinoleate in step (2).

[0044] Comparative Example 5: This comparative example is substantially the same as Example 1, except that: polyethylene glycol glycerol ricinoleate with HLB = 18 (Brij 688, Clariant Sweden AB) is used to replace the polyethylene glycol glycerol ricinoleate in step (2).

[0045] Comparative Example 6: This comparative example is substantially the same as Example 1, except that: the amounts of polyethylene glycol glycerol ricinoleate and purified water are different.

[0046] In this comparative example, the amount of polyethylene glycol glycerol ricinoleate is 400 parts by mass, and the amount of purified water is 400 parts by mass.

[0047] Comparative Example 7: This comparative example is substantially the same as Example 1, except that: the amounts of polyethylene glycol glycerol ricinoleate and purified water are different.

[0048] In this comparative example, the amount of polyethylene glycol glycerol ricinoleate is 300 parts by mass, and the amount of purified water is 500 parts by mass.

[0049] Comparative Example 8: This comparative example is substantially the same as Example 1, except that the amounts of polyethylene glycol glycerol ricinoleate and purified water are different.

[0050] In this comparative example, the amount of polyethylene glycol glycerol ricinoleate used is 200 parts by mass, and the amount of purified water used is 300 parts by mass.

[0051] Comparative Example 9: This comparative example is substantially the same as Example 1, except that the amounts of polyethylene glycol glycerol ricinoleate and purified water are different.

[0052] In this comparative example, the amount of polyethylene glycol glycerol ricinoleate used is 100 parts by mass, and the amount of purified water used is 300 parts by mass.

[0053] Comparative Example 10: This comparative example is substantially the same as Example 1, except that polyethylene glycol is not added in step (3).

[0054] Performance test: 1. Appearance: Observe the appearance and transparency of the sample at rest.

[0055] 2. Median particle size test: Use a laser particle size distribution analyzer to dilute the nanoemulsion to the concentration required for testing by the laser particle size distribution analyzer, and calculate the particle size distribution by measuring light scattering to obtain the median particle size.

[0056] 3. Centrifugal stability: Dilute the nanoemulsion 5 times or 10 times with deionized water, put it into a centrifuge, and centrifuge for 15 min at a rotation speed of (3000 - 10000) / min. After centrifugation, observe whether the sample is layered.

[0057] 4. Storage stability: Seal and store the nanoemulsion in the dark at room temperature (25°C) for 90 days. Take it out every 15 days to measure its particle size and compare it with the particle size before storage. If the ratio of the absolute value of the difference in particle size before and after storage to the particle size before storage is less than 10%, it is considered storage stable; otherwise, it is considered unstable.

[0058] 5. Heat treatment stability: Place the nanoemulsion under the conditions of 40°C and 90 ± 5% RH and observe for 3 weeks. Measure its particle size and compare it with the particle size before heat treatment. If the ratio of the absolute value of the difference in particle size before and after heat treatment to the particle size before heat treatment is less than 10%, it is considered heat treatment stable; otherwise, it is considered unstable.

[0059] 6. Shelf life: Seal and store the nanoemulsion in the dark at room temperature (25°C), and regularly detect indicators such as the appearance, particle size, and Zeta potential of the nanoemulsion. At the same time, observe whether there are phenomena such as layering, precipitation, and deterioration until the emulsion no longer meets the quality requirements, so as to determine its shelf life.

[0060] For the performance test data of the above examples and comparative examples, see Table 1.

[0061]

[0062] Nanocapsules with a small particle size can be absorbed by animals more quickly, reducing the degradation and loss of active ingredients in the gastrointestinal tract, thereby improving the bioavailability of nanocapsules. As can be seen from the above table, the nanocapsules prepared in the examples of the present invention have a smaller particle size, with a median particle size of only about 45 nm, and the proportion of active ingredients (carvacrol, cinnamaldehyde, oleoresin capsicum, and thymol) in the nanocapsules is high, approaching 20%. At the same time, the nanocapsules have a long shelf life and better stability, facilitating storage and transportation under different environmental conditions, and can ensure that the nanocapsules do not degrade, deteriorate, or become ineffective during storage and transportation, ensuring that the active ingredients still maintain high activity when reaching the action site, thereby improving the efficacy of the nanocapsules.

[0063] By comparing Example 1 with Comparative Examples 1 to 9, it can be seen that the emulsifier components and dosage have a significant impact on the performance of nanocapsules. Selecting polyethylene glycol glycerol ricinoleate with an HLB value of 10 - 14 as the emulsifier can significantly reduce the particle size of the emulsion to the nanoscale. However, if the dosage of polyethylene glycol glycerol ricinoleate is too small (less than 35% of the total mass of the nanocapsules) or too large (more than 60% of the total mass of the nanocapsules), it will cause the particle size of the emulsion to be too large, with poor stability and a short shelf life.

[0064] By comparing Example 1 with Comparative Example 10, it can be seen that by adding a cosolvent (such as polyethylene glycol), it can act synergistically with other components to improve the stability and shelf life of the nanocapsules.

[0065] By comparing Example 1 with Example 2, it can be seen that by adding disodium ethylenediaminetetraacetate, it can chelate metal ions in the nanocapsules, thereby further improving the stability of the nanocapsules and extending the shelf life.

[0066] Application test: 2000 7-day-old broiler chickens were randomly divided into 5 representative groups, with 400 chickens in each group. They were fed ad libitum and provided with free access to water. The preliminary trial period was 7 days, and the experimental period was 21 days. The control group was fed a basal diet, and in addition to the basal diet, Test Groups 1 to 4 were respectively added with the nanocapsules of Example 1 and Comparative Examples 1 to 3. The addition amount was 100 g / t of the diet (sprayed after dilution with water). The results are shown in Table 2.

[0067]

[0068] Among them, the feed conversion rate = daily feed intake / daily weight gain. The lower the feed conversion rate value, the less feed is required per unit weight gain, and the higher the breeding efficiency.

[0069] It can be seen that, for the nanoemulsion of the embodiment of the present invention, both the growth rate and feed conversion rate of broilers are optimal. This shows that the nano-sized essential oil has better dispersion effect and higher bioavailability when diluted with water and sprayed into the diet. In addition, the applicant further found through research that when the proportion of oleoresin capsici in the nanoemulsion is too low (less than 3% of the total mass of the nanoemulsion) or too high (more than 5% of the total mass of the nanoemulsion), it will lead to a decrease in feed intake and affect the weight gain of broilers.

[0070] The above has described the present invention in detail. The purpose is to enable those skilled in this field of technology to understand the content of the present invention and implement it. However, it should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A composite essential oil nanoemulsion, characterized in that, Based on the total mass of the composite essential oil nanoemulsion being 100%, the composite essential oil nanoemulsion comprises: Plant essential oil 15% - 30%, and the plant essential oil is selected from two or more of carvacrol, cinnamaldehyde, oleoresin capsici, and thymol; Polyethylene glycol glycerol ricinoleate 40% - 60%, and the HLB value of the polyethylene glycol glycerol ricinoleate is 10 - 14; Cosolvent 10% - 30%; Water 5% - 30%; Vitamin E acetate 0.01% - 0.5%; Ethylenediaminetetraacetate 0 - 0.1%, The median particle size of the composite essential oil nanoemulsion is not greater than 45 nm.

2. The compound essential oil nanoemulsion according to claim 1, characterized in that, The median particle size of the composite essential oil nanoemulsion is 5 nm - 45 nm.

3. The compound essential oil nanoemulsion according to claim 2, wherein The composite essential oil nanoemulsion is a homogeneous liquid and is transparent.

4. The composite essential oil nanoemulsion according to claim 1, characterized in that, The plant essential oil is carvacrol, cinnamaldehyde, oleoresin capsici, and thymol, and the mass content of carvacrol in the composite essential oil nanoemulsion > the mass content of cinnamaldehyde in the composite essential oil nanoemulsion > the mass content of oleoresin capsici in the composite essential oil nanoemulsion > the mass content of thymol in the composite essential oil nanoemulsion.

5. The composite essential oil nanoemulsion according to claim 4, characterized in that, The mass content of carvacrol in the composite essential oil nanoemulsion is 7% - 12%; and / or, The mass content of cinnamaldehyde in the composite essential oil nanoemulsion is 5% - 10%; and / or, The mass content of oleoresin capsici in the composite essential oil nanoemulsion is 2% - 5%; and / or, The mass content of thymol in the composite essential oil nanoemulsion is 1% - 4%.

6. The composite essential oil nanoemulsion according to claim 1, wherein Based on the total mass of the composite essential oil nanoemulsion being 100%, the composite essential oil nanoemulsion comprises: Carvacrol 7% - 10%, Cinnamaldehyde 5% - 10%, Oleoresin capsici 2% - 5%, Thymol 1% - 4%, Polyethylene glycol glycerol ricinoleate 40% - 60%, Cosolvent 15% - 30%, Purified water 5% - 30%, Vitamin E acetate 0.01% - 0.2%, Ethylenediaminetetraacetate 0.01 - 0.05%.

7. The composite essential oil nanoemulsion according to claim 1, characterized in that The cosolvent is selected from one or more of polyethylene glycol and propylene glycol; and / or, The ethylenediaminetetraacetate is disodium ethylenediaminetetraacetate.

8. The preparation method of the composite essential oil nanoemulsion according to any one of claims 1 to 7, characterized in that, Comprises the following steps: (1) Mix the plant essential oil and vitamin E acetate, and stir evenly to prepare an oil phase; (2) Mix the oil phase of step (1) with polyethylene glycol glycerol ricinoleate, and stir evenly to form a mixture; (3) Mix the cosolvent and water, add ethylenediaminetetraacetate, and stir evenly to prepare an aqueous phase; (4) Mix the mixture of step (2) with the aqueous phase of step (3), and stir evenly to prepare the composite essential oil nanoemulsion.

9. The preparation method of the composite essential oil nanoemulsion according to claim 8, characterized in that, The mixing temperature of steps (1) to (4) is independently selected from 30°C - 60°C; and / or, The stirring speed of steps (1) to (4) is independently selected from 1000 r / min - 3000 r / min.

10. Use of the composite essential oil nanoemulsion according to any one of claims 1 to 7, said use comprising adding the composite essential oil nanoemulsion as a feed additive to feed or drinking water.

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