A humic acid-cinnamon essential oil emulsion and preparation and application thereof

Abstract

The present application belongs to the technical field of emulsion, and discloses a humic acid-cinnamon essential oil emulsion as well as preparation and application thereof.The present application adds dried tangerine or orange peel fermented product into an alkaline solution, uniformly stirs, seals, and performs heating and oscillation, then centrifugates to obtain supernatant, acidifies and precipitates, and freeze-dries the precipitate to obtain dried tangerine peel-derived humic acid powder.The dried tangerine peel-derived humic acid powder can form a humic acid-cinnamon essential oil emulsion under neutral conditions with pH=5-9.The humic acid-cinnamon essential oil emulsion prepared from the dried tangerine peel-derived humic acid powder has a simple preparation process, high storage stability at room temperature, and excellent antibacterial performance, and can be applied in the fields of medicine, cosmetics, food, etc.

Description

Technical Field

[0001] This invention belongs to the field of emulsion technology, and specifically relates to a humic acid-cinnamon essential oil emulsion and its preparation and application. Background Technology

[0002] Cinnamon essential oil is a natural, renewable antibacterial agent, with cinnamaldehyde (75-90%) as its active ingredient. Cinnamaldehyde exerts its antibacterial effect by disrupting cell walls and damaging intracellular substances. Currently, cinnamon essential oil is increasingly used in food preservation, animal husbandry, and pest control. However, cinnamon essential oil is volatile, sensitive to light, oxygen, and temperature, has poor stability, and low water solubility, which limits its practical application. To address these issues, existing technologies propose encapsulation and emulsification methods to transport cinnamon essential oil.

[0003] Chinese invention patent publication (CN114869805A) discloses a method for preparing cinnamon essential oil microcapsules using a mixture of chitosan, quaternary ammonium salt, gum arabic, acetic acid, and water as a composite wall material solution. The microcapsules prepared by this invention exhibit excellent antibacterial properties against various bacteria and maintain good antibacterial performance for a relatively long period. However, their antibacterial activity is lower than that of pure cinnamon essential oil, and the preparation process is complex.

[0004] Chinese invention patent publication (CN111589385A) discloses a method for preparing cinnamon essential oil microcapsules using chitosan and sodium alginate as wall materials, sodium chloride as a promoter, and calcium chloride as a curing agent. The microcapsules prepared by this method have a more uniform distribution and show improved controlled-release properties compared to microcapsules prepared by traditional methods. However, the preparation process is complex, and the antibacterial effect needs further investigation.

[0005] While microencapsulation of cinnamon essential oil can improve its stability, it reduces its antibacterial activity and is a complex and cumbersome preparation process. Preparing an emulsion to transport cinnamon essential oil can improve its water solubility, reduce the impact of environmental factors on the oil, and delay oxidation, thereby enhancing its stability.

[0006] In Xinhui District of Jiangmen City, my country, a large quantity of tea-juice tangerines are cultivated annually. The peel of these tangerines, after being peeled, dried, and aged, is made into the renowned Xinhui Chenpi (aged tangerine peel). However, the tangerine pulp, after peeling, is plentiful but inexpensive; only a small amount is used for animal feed and beverages, with the majority being discarded. Long-term accumulation of the pulp leads to sourness and foul odor, and the leachate pollutes water bodies and groundwater, impacting urban and rural environmental sanitation. Composting the tangerine pulp and extracting humic acid from the fermentation products for use in emulsion preparation could promote the resource utilization of Chenpi; however, no relevant technologies or research reports have yet been published.

[0007] Based on the above, we have invented a method for preparing cinnamon essential oil emulsion using humic acid derived from fermented tangerine peel pulp as an emulsifier. Summary of the Invention

[0008] In order to overcome the shortcomings and deficiencies of the prior art, the primary objective of this invention is to provide a method for extracting humic acid from fermented tangerine peel pulp. This method is a resource-based and high-value utilization of tangerine peel pulp, which is conducive to the sustainable development of the environment.

[0009] Another objective of this invention is to provide a method for preparing an oil-in-water emulsion of cinnamon essential oil using humic acid derived from fermented tangerine peel pulp prepared by the above method as an emulsifier. The method for preparing the humic acid-cinnamon essential oil emulsion derived from fermented tangerine peel pulp provided by this invention is simple, has good storage stability, uses humic acid as an emulsifier, is environmentally friendly, low-cost, and possesses certain functionalities.

[0010] Another object of the present invention is to provide the application of the above-mentioned humic acid-cinnamon essential oil emulsion. The humic acid-cinnamon essential oil emulsion provided by the present invention has good antibacterial effects against Escherichia coli and Staphylococcus aureus, and its antibacterial effect is better than that of pure cinnamon essential oil.

[0011] The objective of this invention is achieved through the following solution:

[0012] A method for extracting humic acid from fermented tangerine peel pulp, comprising the following steps:

[0013] The fermented tangerine peel pulp is added to an alkaline solution, stirred evenly, sealed, heated and shaken, then centrifuged to collect the supernatant, acidified to precipitate, and the precipitate is freeze-dried to obtain tangerine peel humic acid freeze-dried powder.

[0014] The fermented tangerine peel and pulp can be purchased from the market or prepared by the following method: Mix Chinese medicine residue, dust-removing rice husks, sawdust, and fermentation agent evenly as bedding material and put it into a fermentation tank. Mix soy sauce residue, tangerine peel and pulp with water to form a slurry liquid. Then spray the slurry liquid onto the bedding material. Under natural ventilation conditions, mechanically turn the pile 1 to 3 times every 1 to 3 days and ferment continuously for 1 to 3 months to obtain the fermented tangerine peel and pulp.

[0015] In the preparation of the fermented tangerine peel and pulp, the medicinal residue is at least one of yam, codonopsis, poria cocos, white hyacinth bean, tangerine peel, amomum villosum, atractylodes macrocephala, and five-finger peach; preferably, it is five-finger peach residue.

[0016] In the preparation of the fermented tangerine peel and pulp, the fermentation agent is at least one of *Xanthomonas pseudoxanthomonas*, *Taurella multocida*, *Bacillus sicca*, *Bacillus halophilus*, *Bacillus subtilis*, *Lactobacillus acidophilus*, and fertilizer fermentation bacteria; preferably, it is a compound agent composed of *Xanthomonas pseudoxanthomonas*, *Taurella multocida*, *Bacillus sicca*, *Bacillus halophilus*, *Bacillus subtilis*, and *Lactobacillus acidophilus*; more preferably, it is the yeast source bacteria from Guangzhou Rongxin Technology Development Co., Ltd.

[0017] In the preparation of the fermented tangerine peel pulp, the volume ratio of sawdust, dust-removing rice husks, and traditional Chinese medicine residue in the bedding material is (1-6):(4-10):(0-2.5), and the amount of fermentation agent added is 1 ml. 3 Add 150-450g of fermentation agent to the bedding material.

[0018] In the preparation of the fermented tangerine peel and pulp, the volume ratio of soy sauce residue, tangerine peel and pulp to water is (0.3-1):(1-20):90;

[0019] In the preparation of the fermented tangerine peel and pulp, the moisture content in the fermentation tank is adjusted to 60% to 70% by controlling the spraying amount of the slurry liquid, and the carbon-nitrogen ratio is (20 to 30):1.

[0020] In the method for extracting humic acid from fermented tangerine peel pulp, the alkaline solution is preferably a mixed aqueous solution of sodium pyrophosphate and alkali, wherein the alkali is at least one of sodium hydroxide and potassium hydroxide, and the molar ratio of sodium pyrophosphate to alkali is (0.5-2):(0.5-2).

[0021] In the method for extracting humic acid from fermented tangerine peel and pulp, the concentration of sodium pyrophosphate in the alkaline solution is 0.05-0.2 mol / L, preferably 0.1 mol / L; the mass-to-volume ratio of the fermented tangerine peel and pulp to the alkaline solution is 1 g: 6-20 mL, preferably 1 g: 10 mL.

[0022] In the method for extracting humic acid from fermented tangerine peel pulp, the heating and oscillation refers to heating to 45-60℃ and oscillating for 18-24 hours; preferably, oscillating in a 60℃ air bath constant temperature oscillator for 24 hours. The oscillation is to ensure sufficient contact between the raw materials, and all oscillation speeds can achieve the technical effect of this invention; therefore, the oscillation speed does not need to be limited.

[0023] To ensure complete extraction, after centrifugation and obtaining the supernatant, the precipitate can be repeatedly washed with water until the liquid phase is clear. The resulting washing liquid and supernatant are then combined and proceeded to the next step.

[0024] In the method for extracting humic acid from fermented tangerine peel and pulp, the acidification precipitation refers to adjusting the pH of the filtrate to 1-2. The acid used for acidification is dilute hydrochloric acid with a concentration of 3-6 mol / L, preferably 6 mol / L. The freeze-drying is preferably liquid nitrogen freeze-drying.

[0025] After acidification, it is preferable to wash the precipitate with water at least three times to remove any residual soluble substances, leaving a precipitate that is insoluble in acidic solutions.

[0026] A humic acid derived from tangerine peel prepared by the above method.

[0027] The above-mentioned tangerine peel-derived humic acid was used as an emulsifier in the preparation of cinnamon essential oil oil-in-water emulsion.

[0028] A method for preparing a cinnamon essential oil water-in-oil emulsion includes the following steps:

[0029] (1) Disperse the prepared tangerine peel humic acid freeze-dried powder in water to obtain tangerine peel humic acid solution.

[0030] (2) Add cinnamon essential oil to the humic acid solution of tangerine peel and shear to prepare cinnamon essential oil water-in-oil emulsion.

[0031] The pH of the tangerine peel humic acid solution mentioned in step (1) is 5-9; the pH is adjusted by adding alkali, preferably by using sodium hydroxide solution; the concentration of the tangerine peel humic acid solution is 5-20 mg / ml.

[0032] The relative amounts of tangerine peel humic acid solution and cinnamon essential oil mentioned in step (2) satisfy the following: the volume ratio of cinnamon essential oil to tangerine peel humic acid solution is 1:1-1:4.

[0033] The shearing mentioned in step (2) refers to shearing at 90,000-150,000 rpm for 3-5 minutes, preferably at 10,000 rpm for 4 minutes.

[0034] A cinnamon essential oil emulsion in water prepared by the above method.

[0035] The above-mentioned cinnamon essential oil water-in-oil emulsion has high storage stability at room temperature and excellent antibacterial properties, and can be used in the fields of medicine, cosmetics, and food.

[0036] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0037] (1) The emulsifier used in this invention is humic acid derived from fermented tangerine peel pulp, which is low in cost, easy to obtain, green and environmentally friendly. Furthermore, this humic acid can form an emulsion under neutral conditions of pH 5 to 9, and has a wide range of applications.

[0038] (2) The preparation process of the fermented tangerine peel pulp source humic acid-cinnamon essential oil emulsion in this invention is simple, has high storage stability at room temperature, and has excellent antibacterial properties. It can be applied to the fields of medicine, cosmetics, food, etc. Attached Figure Description

[0039] Figure 1 The image shows the appearance of the commercial humic acid-cinnamon oil emulsion prepared in Comparative Example 4.

[0040] Figure 2 The images show optical micrographs of the humic acid-cinnamon essential oil emulsions derived from fermented tangerine peel pulp prepared in Examples 1-3 and Comparative Example 1. A, b, d, and e correspond to Comparative Example 1 and Examples 1-3, respectively, while c is a magnified view of the optical micrograph of the emulsion from Example 1.

[0041] Figure 3 The images show the appearance of the humic acid-cinnamon essential oil emulsion derived from fermented tangerine peel pulp prepared in Examples 1-3 and Comparative Example 1 after storage at room temperature for 0 h and 360 h, respectively. In the images, a and b correspond to Comparative Example 1 and Examples 1-3, respectively, and e is a magnified view of Comparative Example 1 after 360 h of preparation.

[0042] Figure 4 The figures are optical microscope images of Examples 4-7, with the curves representing the emulsion particle size distribution measured by a laser particle size analyzer (MALVERN MS3000). a and d correspond to Examples 4-7 respectively.

[0043] Figure 5 The images show the appearance of the humic acid-cinnamon essential oil emulsion derived from fermented tangerine peel pulp prepared in Examples 4, 5 and Comparative Example 2 after storage at room temperature for different times. a corresponds to Example 5, b corresponds to Example 4, and c corresponds to Comparative Example 2.

[0044] Figure 6 The images show the appearance of Examples 6, 7 and Comparative Example 3 after being stored at room temperature for different times. a corresponds to Example 7, b corresponds to Example 6, and c corresponds to Comparative Example 3.

[0045] Figure 7 The following are characterization diagrams of the antibacterial properties of Example 7. a) shows the inhibitory effect of the humic acid-cinnamon essential oil emulsion derived from tangerine peel fermentation product on *Escherichia coli*; b) shows the inhibitory effect of cinnamon essential oil on *Escherichia coli*; c) shows the inhibitory effect of humic acid derived from tangerine peel fermentation product on *Escherichia coli*; d) shows the antibacterial inhibition of the humic acid-cinnamon essential oil emulsion derived from tangerine peel fermentation product on *Staphylococcus aureus*; e) shows the inhibitory effect of cinnamon essential oil on *Staphylococcus aureus*; and f) shows the inhibitory effect of humic acid derived from tangerine peel fermentation product on *Staphylococcus aureus*. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0047] Example 1

[0048] A tangerine peel humic acid-cinnamon essential oil emulsion with an oil-water volume ratio of 1:3 was prepared, wherein the tangerine peel humic acid solution had a pH of 5 and a concentration of 5 mg / ml.

[0049] (1) Preparation of fermented tangerine peel and pulp: Mix five-finger peach residue, dust-removed rice husks and sawdust in a volume ratio of 2:7:3, and then add 300g / m 3 The compound fermentation agent (Yeast Source Bacteria from Guangzhou Rongxin Technology Development Co., Ltd.) of the bedding material was mixed evenly and fed into the fermentation tank. Soy sauce residue (from Lee Kum Kee), tangerine peel pulp, and water were mixed in a volume ratio of 1:20:90 to form a slurry. The slurry was then sprayed onto the bedding material. The moisture content of the materials in the fermentation tank was 65%, and the carbon-to-nitrogen ratio was 25:1. Under natural ventilation, the material was mechanically turned once a day and fermented continuously for one month to obtain the tangerine peel pulp fermented product. 。

[0050] (2) Preparation of humic acid from fermented tangerine peel and pulp: 15g of fermented tangerine peel and pulp was added to 150ml of a mixture of sodium pyrophosphate and sodium hydroxide (molar ratio of sodium pyrophosphate to sodium hydroxide was 1:1, and both concentrations were 0.1mol / L). After thorough stirring, the mixture was transferred to a 250mL Erlenmeyer flask, sealed with plastic wrap, and placed in a gas bath constant temperature shaker at 60℃ for 24h. After shaking, the mixture was centrifuged at 8000rpm for 5min, and the supernatant was collected. The precipitate was repeatedly washed with deionized water until the liquid phase was clear, and the washing liquid was obtained. The washing liquid and supernatant were combined and filtered. The pH of the filtrate was adjusted to 1-2 with 6mol / L hydrochloric acid to precipitate the humic acid from the fermented tangerine peel and pulp. The precipitate was washed with deionized water and centrifuged at 8000rpm for 5min. The supernatant was discarded, and the process was repeated three times. The final precipitate was humic acid. The precipitate was freeze-dried to obtain lyophilized powder of humic acid from fermented tangerine peel and pulp.

[0051] (3) Preparation of humic acid solution from fermented tangerine peel pulp: Take 0.06g of the freeze-dried powder of humic acid from fermented tangerine peel pulp obtained in step (2) and disperse it in 12ml of deionized water to obtain a humic acid solution from fermented tangerine peel pulp with a concentration of 5mg / ml. Add NaOH solution to adjust the pH of the humic acid solution to 5.

[0052] (4) Preparation of humic acid-cinnamon essential oil emulsion from fermented tangerine peel pulp: Take 12 ml of humic acid solution from fermented tangerine peel pulp prepared in step (2), add 4 ml of cinnamon essential oil, and use a disperser to shear at high speed at 10000 rpm for 4 min to obtain humic acid-cinnamon essential oil emulsion from fermented tangerine peel pulp.

[0053] Example 2

[0054] The pH of step (3) in implementation 1 was adjusted to 7, while the rest remained the same as in Example 1. A humic acid-cinnamon essential oil emulsion derived from tangerine peel fermentation product with an oil-water ratio of 1:3 was prepared, wherein the humic acid solution derived from tangerine peel fermentation product had a pH of 7 and a concentration of 5 mg / ml.

[0055] Example 3

[0056] The pH of step (3) in implementation 1 was adjusted to 9. Everything else remained the same as in Example 1, and a humic acid-cinnamon essential oil emulsion derived from tangerine peel fermentation product with an oil-water ratio of 1:3 was prepared, wherein the humic acid solution derived from tangerine peel fermentation product had a pH of 9 and a concentration of 5 mg / ml.

[0057] Example 4

[0058] The step (3) in Example 1 was adjusted as follows: 0.16g of lyophilized humic acid powder from fermented tangerine peel pulp was dispersed in 8ml of deionized water to obtain a humic acid solution with a concentration of 20mg / ml.

[0059] Adjust the pH of step (3) in implementation 1 to 7.

[0060] The step (4) in Example 1 is adjusted as follows: Take 8 ml of humic acid solution from fermented tangerine peel pulp and add 4 ml of cinnamon essential oil to it.

[0061] The rest is consistent with Implementation 1, and an oil-water ratio of 1:2 is used to prepare a humic acid-cinnamon essential oil emulsion derived from tangerine peel fermentation product, wherein the humic acid solution derived from tangerine peel fermentation product has a pH of 7 and a concentration of 20 mg / ml.

[0062] Example 5

[0063] The step (3) in Example 1 was adjusted as follows: 0.32g of lyophilized humic acid powder from fermented tangerine peel pulp was dispersed in 16ml of deionized water to obtain a humic acid solution with a concentration of 20mg / ml.

[0064] Adjust the pH of step (3) in implementation 1 to 7.

[0065] The step (4) in Example 1 is adjusted as follows: Take 16 ml of humic acid solution from fermented tangerine peel pulp and add 4 ml of cinnamon essential oil to it.

[0066] The rest is consistent with Implementation 1, and an oil-water ratio of 1:4 is obtained to prepare a humic acid-cinnamon essential oil emulsion derived from tangerine peel fermentation product, wherein the humic acid solution derived from tangerine peel fermentation product has a pH of 7 and a concentration of 20 mg / ml.

[0067] Example 6

[0068] The step (3) in Example 1 was adjusted as follows: 0.09g of humic acid from fermented tangerine peel pulp was dispersed in 6ml of deionized water to obtain a humic acid solution with a concentration of 15mg / ml.

[0069] Adjust the pH of step (3) in implementation 1 to 7.

[0070] The step (4) in Example 1 is adjusted as follows: Take 6 ml of humic acid solution from fermented tangerine peel pulp and add 6 ml of cinnamon essential oil to it.

[0071] The rest is consistent with Implementation 1, and an oil-water ratio of 1:1 is obtained to prepare a humic acid-cinnamon essential oil emulsion derived from tangerine peel fermentation product, wherein the humic acid solution derived from tangerine peel fermentation product has a pH of 7 and a concentration of 15 mg / ml.

[0072] Example 7

[0073] The step (3) in Example 1 was adjusted as follows: 0.12g of humic acid from fermented tangerine peel pulp was dispersed in 6ml of deionized water to obtain a humic acid solution with a concentration of 20mg / ml.

[0074] Adjust the pH of step (3) in implementation 1 to 7.

[0075] The step (4) in Example 1 is adjusted as follows: Take 6 ml of humic acid solution from fermented tangerine peel pulp and add 6 ml of cinnamon essential oil to it.

[0076] The rest is consistent with Implementation 1, and an oil-water ratio of 1:1 is obtained to prepare a humic acid-cinnamon essential oil emulsion derived from tangerine peel fermentation product, wherein the humic acid solution derived from tangerine peel fermentation product has a pH of 7 and a concentration of 20 mg / ml.

[0077] from Figure 2 As can be seen from b, d, and e, under the conditions of pH=5, pH=7, and pH=9, the humic acid from the fermented product of tangerine peel pulp can stabilize the oil-water interface, encapsulating oil droplets to form an emulsion. Figure 3 The appearance of the emulsion also shows that the lower layer of the emulsion at pH=5, pH=7 and pH=9 is milky white and emulsion-like. The water layer of the emulsion separates, causing the emulsion to separate. This is because the density of cinnamon essential oil is greater than that of water. The emulsion droplets settle in the system due to gravity, but this process does not destroy the emulsion structure.

[0078] Comparative Example 1

[0079] The pH in step (3) of implementation 1 was adjusted to 3. Everything else remained the same as in Example 1.

[0080] like Figure 2 As shown in figure a, under pH=3 conditions, humic acid particles derived from tangerine peel fermentation were adsorbed onto the surface of cinnamon essential oil, but no emulsion droplets were observed. Figure 3 As can be seen from the image, after standing, the upper layer is a clear aqueous phase and the lower layer is a clear oil phase. The oil and water are completely separated, and no emulsion is formed.

[0081] Comparative Example 2

[0082] The step (3) in Example 1 is adjusted as follows: 0.08g of humic acid from fermented tangerine peel pulp is dispersed in 4ml of deionized water to obtain a humic acid solution with a concentration of 20mg / ml.

[0083] Adjust the pH of step (3) in implementation 1 to 7.

[0084] The step (4) in Example 1 is adjusted as follows: Take 4 ml of humic acid solution from fermented tangerine peel pulp and add 8 ml of cinnamon essential oil to it.

[0085] Everything else remains consistent with Implementation 1, such as Figure 5 As shown in c, the prepared emulsion separated into oil and water after being left at room temperature for 24 hours, and a stable emulsion could not be obtained.

[0086] Comparative Example 3

[0087] The step (2) in Example 1 is adjusted as follows: 0.02g of humic acid from fermented tangerine peel pulp is dispersed in 8ml of deionized water to obtain a humic acid solution with a concentration of 2.5mg / ml.

[0088] Adjust the pH of step (2) in implementation 1 to 7.

[0089] The step (3) in Example 1 is adjusted as follows: Take 8 ml of humic acid solution from fermented tangerine peel pulp and add 8 ml of cinnamon essential oil to it.

[0090] Everything else remains consistent with Implementation 1, such as Figure 6 As shown in (d), compared with Examples 6 and 7, Comparative Example 3 demulsified and separated into oil and water after being placed at room temperature for 480 hours.

[0091] Comparative Example 4

[0092] The step (3) in Example 1 was adjusted as follows: 0.12g of commercial humic acid (Shanghai Yuanye Biotechnology Co., Ltd.) was dispersed in 6ml of deionized water to obtain a humic acid solution with a concentration of 20mg / ml.

[0093] Adjust the pH of step (3) in implementation 1 to 7.

[0094] The step (4) in Example 1 is adjusted as follows: Take 6 ml of commercial humic acid solution and add 6 ml of cinnamon essential oil to it.

[0095] Everything else remained consistent with Example 1, resulting in a commercial humic acid-cinnamon essential oil mixture with an oil-to-water ratio of 1:1. The commercial humic acid solution had a pH of 7 and a concentration of 20 mg / ml. The appearance of the commercial humic acid-cinnamon essential oil emulsion prepared in Comparative Example 4 is shown in the figure below. Figure 1 As shown in Comparative Example 4, oil and water separation occurred. Clear oil droplets adhered to the surface of the glass bottle, while the upper layer was a clear aqueous phase, which could not form an emulsion.

[0096] Test method:

[0097] Elemental analysis: The N, C, H, and O content of commercial humic acid (Shanghai Yuanye Biotechnology Co., Ltd.) and the humic acid from the fermented tangerine peel pulp in Example 2 of this invention were determined using an elemental analyzer (Elementar Vario EL cube) at pH=7. The results are shown in Table 1 below.

[0098] Table 1

[0099]

[0100] Elemental composition and atomic ratios can reflect the molecular structure and origin of humic acid. Table 1 above shows the elemental composition and atomic ratios of humic acid from fermented tangerine peel pulp and commercial humic acid from lignite. Compared to commercial humic acid, humic acid from fermented tangerine peel pulp has higher N, H, and O content and lower C content, resulting in higher N / C, H / C, O / C, and [(N+O) / C] ratios. The higher N / C ratio of humic acid from fermented tangerine peel pulp is mainly due to the addition of more protein raw materials (soy sauce residue) during composting; a higher H / C ratio indicates lower aromaticity; a high O / C ratio indicates the presence of more aliphatic compounds; [(N+O) / C] is called the polarity index, and a higher [(N+O) / C] ratio indicates stronger polarity of humic acid from fermented tangerine peel pulp.

[0101] Microstructure of the emulsion: A small amount of fresh emulsion was used to prepare a glass slide specimen, and the microstructure was observed at 400× magnification under a Macody optical microscope (BA410EMotic).

[0102] Emulsion storage stability: Observe the changes in appearance of the emulsion after storage at room temperature for different periods of time.

[0103] Characterization of emulsion antibacterial properties:

[0104] Take 50 μL of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 43894) cultures (OD600 = 0.1), respectively, transfer them to LB solid agar medium (Guangdong Huankai Microbial Technology Co., Ltd.), spread them evenly, and let the bacterial solutions air dry naturally.

[0105] A filter paper disc (d = 0.6 cm) was placed in the center of a plate, and 10 μL of the humic acid-cinnamon oil emulsion derived from the fermented tangerine peel pulp prepared in Example 7 was added to the filter paper disc. The plate was incubated at 37°C for 24 hours. The diameter of the inhibition zone was measured, with each measurement taken three times and the average value recorded. Each bacterium was tested in at least three replicates. Cinnamon oil alone and the humic acid solution derived from the fermented tangerine peel pulp were used as controls, with 10 μL added to each. The size of the inhibition zone was as follows: Figure 7 As shown in Table 2, the diameter of the inhibition zone is as follows.

[0106] Table 2

[0107]

[0108] Measurement data showed that the inhibition zones of the emulsion and cinnamon essential oil against *Escherichia coli* were smaller than those against *Staphylococcus aureus*. This is because the lipopolysaccharides on the cell wall of *E. coli* effectively limit the diffusion of hydrophobic substances. Simultaneously, *E. coli* possesses a membrane, which also resists the effects of adverse external environments. Conversely, the hydrophobic compound cinnamon essential oil can penetrate the peptidoglycan layer of *Staphylococcus aureus*. Furthermore, data indicated that the humic acid-cinnamon essential oil emulsion derived from tangerine peel fermentation products reduced the volatility of cinnamon essential oil, improving its antibacterial properties.

[0109] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A cinnamomum oil-in-water emulsion, characterized in that Prepared by the following method: (1) dispersing the dried Chenpi-source humic acid powder in water to obtain a Chenpi-source humic acid solution; (2) adding cinnamon essential oil to the Chenpi-source humic acid solution to prepare a cinnamon essential oil oil-in-water emulsion by shearing; The dried Chenpi-source humic acid powder is prepared by the following method: The Chenpi-source humic acid powder is prepared by the following method: adding the Chenpi-pomelo meat ferment to an alkaline solution, stirring uniformly, sealing and heating and oscillating, then centrifuging to obtain the supernatant, acidifying and precipitating, freezing and drying the precipitate to obtain the dried Chenpi-source humic acid powder; The Chenpi-pomelo meat ferment is prepared by the following method: mixing traditional Chinese medicine residues, dust-removing rice hulls, wood flour and fermentation inoculum uniformly as bedding and feeding into a fermentation tank, mixing soy sauce residues, Chenpi-pomelo meat and water into a slurry, then spraying the slurry on the bedding, mechanically turning the pile once to three times every 1 to 3 days under natural ventilation conditions, continuously fermenting for 1 to 3 months to obtain the Chenpi-pomelo meat ferment; In the preparation of the Chenpi-pomelo meat ferment, the traditional Chinese medicine residues are Radix Fici Hirtae; In step (1), the pH of the Chenpi-source humic acid solution is 5-9, and the concentration of the Chenpi-source humic acid solution is 5-20 mg / ml; In step (2), the relative amount of the Chenpi-source humic acid solution and the cinnamon essential oil satisfies the volume ratio of 1:1-1:

4.

2. The cinnamon essential oil oil-in-water emulsion according to claim 1, characterized in that: In the preparation of the Chenpi-pomelo meat ferment, the fermentation inoculum is a complex inoculum composed of Pseudomonas, Trower's bacteria, Bacillus siamensis, Haloterrigena taiwenensis, Bacillus subtilis and Lactobacillus acidophilus; The preparation of the Chenpi orange meat ferment, the volume ratio of wood chaff, dust-free chaff and traditional Chinese medicine residue in the padding is (1-6):(4-10):(0-2.5), and the amount of bacterial agent added is 1 m 3 The corresponding 150-450 g of fermentation bacterial agent is added in the padding. In the preparation of the Chenpi-pomelo meat ferment, the volume ratio of the soy sauce residues, Chenpi-pomelo meat and water is (0.3-1):(1-20):90; In the preparation of the Chenpi-pomelo meat ferment, the water content in the fermentation tank is adjusted to 60%-70% and the carbon-nitrogen ratio is (20-30):1 by controlling the spraying amount of the slurry.

3. The cinnamon essential oil oil-in-water emulsion according to claim 1, characterized in that the alkaline solution is a mixed aqueous solution of sodium pyrophosphate and a base, wherein the base is at least one of sodium hydroxide and potassium hydroxide, and the molar ratio of sodium pyrophosphate to base is (0.5-2):(0.5-2); In the preparation of the Chenpi-pomelo meat ferment, the concentration of sodium pyrophosphate in the alkaline solution is 0.05-0.2 mol / L, and the mass-volume ratio of the Chenpi-pomelo meat ferment and the alkaline solution is 1 g:6-20 mL.

4. The cinnamon essential oil oil-in-water emulsion according to claim 1, characterized in that: the heating and oscillation refers to heating to 45-60℃ and oscillating for 18-24h; The acidification and precipitation refers to adjusting the pH of the filtrate to 1-2, and the freeze-drying is liquid nitrogen freeze-drying.

5. The cinnamon essential oil oil-in-water emulsion according to claim 1, characterized in that in step (2), the shearing refers to shearing at 90000-150000 rpm for 3-5 min.

6. Use of the cinnamon essential oil oil-in-water emulsion according to any one of claims 1-5 in cosmetics. ​ ​ ​

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