A menthol essential oil emulsion for preventing and treating ham pests and a preparation method thereof

Abstract

The application provides application of peppermint essential oil in prevention and treatment of ham pests and a preparation scheme of a peppermint essential oil emulsion, and belongs to the technical field of ham pest prevention and treatment.The application first discovers a new use of the peppermint essential oil in the prevention and treatment of ham pests, and prepares a peppermint essential oil emulsion from the peppermint essential oil, chitosan, acetic acid, glycerol, Tween 80 and water.The safety of the obtained emulsion is much higher than that of traditional chemical insecticide methods, the method has low cost, is simple to prepare, and has remarkable effects, and the method shows good effects in oviposition repelling of cheese fly adults, pupation inhibition of 3rd instar larvae, pupa emergence inhibition and contact toxicity of 2nd instar larvae.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ham pest control, and particularly relates to a peppermint essential oil emulsion for preventing and treating ham pests and a preparation method thereof. BACKGROUND

[0002] Dry-cured ham is a traditional Chinese delicacy. It is loved by the public because of its unique characteristics such as non-greasy, rich salty flavor, unique flavor, green and healthy. However, during the production process of traditional dry-cured ham, it is easily infested by cheese flies and cheese mites and other pests, which seriously threatens the quality and safety of dry-cured ham. Pests not only infest the inside of ham, causing ham to spoil, deteriorate, and turn black, but also may carry harmful bacteria such as Providencia stuartii, increasing the risk of food safety. Therefore, solving the problem of ham pests is not only crucial to the economic benefits of enterprises, but also related to the health and safety of consumers. Effective control measures are urgently needed.

[0003] At present, the main methods for preventing and treating pests in dry-cured ham include space isolation and chemical insecticides. However, each method has its own limitations. The space isolation method has a wide range of applications. It uses a 600-1200 mesh screen to cover and block cheese fly adults from laying eggs in the ham. However, the dense screen may affect the evaporation of water in the ham, prolong the production cycle, and the control effect on cheese mites is not ideal. On the other hand, although chemical insecticides have a certain control effect, they still pose a food safety risk due to the presence of toxic ingredients such as amyl alcohol and n-pentyl formate.

[0004] Therefore, it is urgent to develop a more green and safe control technology to ensure the quality of ham and the health of consumers. SUMMARY

[0005] Therefore, the present application aims to provide a peppermint essential oil emulsion for preventing and treating ham pests and a preparation method thereof. The present application first discovers the new use of peppermint essential oil in ham pest control, and the prepared peppermint essential oil emulsion is much safer than traditional chemical insecticide methods. This method is low in cost, simple to prepare, and has a significant effect. It shows good results in egg-laying avoidance of cheese fly adults, pupation inhibition of 3rd instar larvae, pupation inhibition of pupae, and contact toxicity of 2nd instar larvae.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] In a first aspect, the present application provides the use of peppermint essential oil in the prevention and treatment of ham pests.

[0008] In a second aspect, the present application provides a peppermint essential oil emulsion for preventing and treating ham pests, characterized in that it comprises the following components by weight:

[0009] Peppermint essential oil 1-10%, chitosan 1-3%, cosolvent aqueous solution 1-3%, plasticizer 0.5-1.5%, emulsifier 0.5-1.5%, and the rest water.

[0010] By using the above scheme, the problem that the strong flavor and high volatility of peppermint essential oil may affect the flavor and taste of food when directly used in food is solved, the influence on the flavor and taste of ham is obviously reduced by using the chitosan (CS) based essential oil emulsion coating, and the action time of peppermint essential oil is prolonged.

[0011] As preferred, the cosolvent aqueous solution comprises one or more of acetic acid, lactic acid, citric acid, malic acid, ascorbic acid, acetic acid, tartaric acid, and phosphoric acid.

[0012] As preferred, the plasticizer comprises one or more of glycerol, tributyl citrate, acetyl tributyl citrate, epoxy soybean oil, sorbitan fatty acid ester, epoxidized linseed oil, and polyethylene glycol.

[0013] As preferred, the emulsifier comprises one or more of Tween, calcium carbonate, Span, fatty acid salt, sulfate salt, gelatin, and gum arabic.

[0014] As preferred, the peppermint essential oil is extracted from the aboveground parts of Mentha haplocalyx Briq. by using the steam distillation method.

[0015] As preferred, the main active ingredients of the peppermint essential oil comprise menthol, limonene, menthone, sabinene, β-pinene, and eucalyptol.

[0016] As preferred, the peppermint essential oil emulsion further comprises a pharmaceutically acceptable excipient.

[0017] As preferred, the pharmaceutically acceptable excipient comprises a solubilizer, a cosolvent aqueous solution, an emulsifier, a coloring agent, a binding agent, a disintegrating agent, a filling agent, a lubricant, a wetting agent, an osmotic pressure regulator, a stabilizer, a glidant, a flavoring agent, a preservative, a suspending agent, a coating material, an aromatic agent, an anti-adhesion agent, an integrating agent, a penetration enhancer, a pH regulator, a buffer, a plasticizer, a surfactant, a foaming agent, an antifoaming agent, a thickening agent, a complexing agent, a humectant, an absorbent, a diluent, a flocculating agent, a deflocculating agent, a filtering aid, and a release retardant.

[0018] As preferred, the peppermint essential oil emulsion can be prepared into a powder or a spray.

[0019] In a third aspect, the present application provides a preparation method of the peppermint essential oil emulsion for preventing and treating pests of ham, comprising the following steps:

[0020] 1) weighing each raw material according to the weight parts;

[0021] 2) Dissolve chitosan in an aqueous co-solvent solution and mix thoroughly to obtain solution A;

[0022] 3) Mix solution A with the plasticizer until homogeneous to obtain solution B;

[0023] 4) Mix solution B, peppermint essential oil, and emulsifier evenly to obtain a peppermint essential oil emulsion for controlling ham pests.

[0024] Preferably, the mixing temperature in step 2) is 20-30℃ and the time is 2-6h.

[0025] Preferably, the mixing temperature in step 3) is 20-30℃ and the time is 1-3h.

[0026] Fourthly, the present invention provides the application of the above-mentioned peppermint essential oil emulsion in the prevention and control of pests affecting ham, including cheese flies, carrion mites, and red-necked coconut beetles.

[0027] Preferably, the prevention and control methods include repellency, inhibition, contact killing, or fumigation.

[0028] Preferably, the stages of pest control include egg, larva, pupa, and adult stages.

[0029] It contains at least the following beneficial technical effects:

[0030] 1) This invention is the first to discover a new use for peppermint essential oil in the control of pests affecting ham. This use is mainly achieved through the repellent, inhibitory, and lethal effects of peppermint essential oil on different developmental stages of the pests.

[0031] 2) This invention reduces the impact on the flavor and color of ham by mixing chitosan with peppermint oil and emulsifying it.

[0032] 3) The peppermint oil emulsion of this invention is far safer than traditional chemical insecticide methods. This method is low-cost, easy to prepare, and highly effective, demonstrating good results in repelling adult jackflies from oviposition, inhibiting the pupation of 3rd instar larvae, inhibiting the emergence of pupae, and reducing contact toxicity in 2nd instar larvae. This provides insights for the application of peppermint oil in pest control in dried cured ham. Attached Figure Description

[0033] Figure 1 Particle size distribution of peppermint essential oil emulsions at different concentrations;

[0034] Figure 2 Electronic tongue sensory rating chart of adding different concentrations of essential oil emulsions to dry-cured ham;

[0035] Figure 3 Images showing color differences between different groups of ham treated with different essential oil emulsions;

[0036] Figure 4 Illustration of the repellent effect of adding essential oil emulsion to dry-cured ham on cheese fly larvae;

[0037] Figure 5 A diagram showing the local contact toxicity effect of peppermint essential oil emulsion on second-instar larvae of tyrosinus fly;

[0038] Figure 6 The diagram shows the inhibitory effect of peppermint essential oil emulsion on the pupation of third-instar larvae of the botfly through local contact.

[0039] Figure 7 Graph showing the toxicity-inhibiting effect of peppermint essential oil emulsion on the emergence of pupae in jackfly;

[0040] Figure 8 A statistical chart showing the number of eggs laid by adult cheese flies after covering ham with essential oil emulsions of different concentrations.

[0041] Figure 9 Comparative images showing the egg-laying of adult cheese flies on the surface of ham. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0043] The terms “comprising” or “including” in this invention are open-ended descriptions that include the specified ingredients or steps described, as well as other specified ingredients or steps that do not materially affect them.

[0044] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0045] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0046] The peppermint essential oil used in this invention can be selected from any part of peppermint or its plant or extracted.

[0047] The peppermint essential oil used in the following examples was sourced from Ji'an Guoguang Fragrance Factory.

[0048] Example 1

[0049] Chemical composition analysis of essential oils: A standardized extraction process was used to analyze the chemical composition of the essential oils (Caballero-Gallardoe et al., 2011). First, 5g of essential oil sample was placed in a 20mL headspace vial and equilibrated at room temperature (25±2℃) for 30 min. Next, volatile components were adsorbed using a 50 / 30-μm DVB / Carboxen / PDMS extraction fiber and gently shaken at 50℃ for 30 min using SPME technology. Gas chromatography (GC) analysis was performed using a gas chromatograph equipped with a triple quadrupole mass spectrometer. During analysis, chromatographic separation was performed using a nonpolar HP-5MS column (30m×0.25mm×0.25μm) and a polar HP-Innowax column (30m×0.25mm×0.25μm). The chromatographic conditions were set as follows: initial temperature 50℃, held for 10 min; then increased to 150℃ at a rate of 5℃ / min and held for 3 min; then increased to 240℃ at a rate of 5℃ / min and held for 3 min. Mass spectrometry (MS) employed electron impact ionization (EI+) with an ionization energy of 70 eV, an ion source temperature of 250℃, a transfer line temperature of 240℃, and a mass analysis range of 35-550 amu. GC-MS data, combined with retention indices, were used for compound identification using the NIST17 and Wiley9 databases. The main active ingredients are shown in Table 1.

[0050] Table 1

[0051]

[0052] Example 2

[0053] 1. The repellent effect of peppermint essential oil on cheese fly larvae.

[0054] The repellent effect of peppermint essential oil on tyrosper larvae: This study's tyrosper larvae repellency experiment was adapted from the method of Kumar et al. (2014) to explore the effect of essential oil on the antifeeding behavior of tyrosper larvae. A Piper dish (Φ90mm) was used, divided into two equal parts. Broth was added to the control group, while different concentrations of essential oil-broth mixtures (10%, 50%, 100%) were added to the test group. To prevent the evaporation of water vapor from the broth from affecting the experimental results, a hole was manually made at the top of the dish. 1.0±0.1g of 10mm×10mm×5mm alternating layers of lean and fat ham were placed in each part. At the start of the experiment, 20 tyrosper larvae were placed at the boundary between the control and test groups, and their gravitational behavior was observed and recorded. Records were taken every 12 hours for a total of 48 hours. The repellency rate was calculated as shown in equation (1):

[0055]

[0056] In the formula, Cn is the number of tyrosine flies appearing in the untreated (control) part, and Tn is the number of tyrosine flies appearing in the treated part.

[0057] Statistics show that 50% concentration peppermint essential oil has a repellent effect on tyrosin fly larvae of 66% after 24 hours and 75% after 48 hours; 100% concentration peppermint essential oil has a repellency rate of 72% after 24 hours and 82% after 48 hours.

[0058] 2. Local contact toxicity of peppermint essential oil to second instar larvae of cheeseflies.

[0059] This study, based on the characteristics that second-instar larvae of the terrapin cannot jump and cannot pupate compared to third-instar larvae, referenced and optimized the local contact toxicity test method for human pests from Kumaret et al. (2013) to evaluate the effects of three essential oils on young terrapin larvae. The experiment was conducted in Piper dishes (Φ90 mm). First, the essential oils were diluted with anhydrous ethanol and evenly dispersed on filter paper (0.5-5 μL / cm). 2 The total volume of filter paper was controlled at 636 μL / sheet. The control group was treated with anhydrous ethanol only. After treatment, the filter paper was air-dried in a fume hood at 25°C for 5 min to accelerate solvent evaporation. Subsequently, 10 second-instar larvae were placed in each petri dish, along with 1.0 ± 0.1 g of 10 mm × 10 mm × 5 mm alternating slices of ham. The experiment lasted for 48 h, and larval survival data were recorded. Each group was repeated 5 times. If the second-instar larvae of botflies did not react after 48 h or did not move under strong light, they were considered dead.

[0060] According to statistics, the LC50 of peppermint essential oil's 48-hour contact toxicity to second-instar larvae of tyrosinase was... 30 It is 2.944 μL / cm 2 LC 50 3.66 μL / cm 2 LC 90 It is 6.231 μL / cm 2 .

[0061] 3. Peppermint essential oil has a local contact pupation inhibitory toxicity on third-instar larvae of the botfly.

[0062] This study aimed to improve the local contact toxicity test method for third-instar larvae of the terrapin (Bacteroides spp.), as described by Kumar et al. (2013), to evaluate the local contact inhibitory effect of essential oils on these larvae. The experiment was conducted in Piper dishes (Φ90 mm). First, the essential oils were diluted with anhydrous ethanol and evenly dispersed on filter paper (0.5-10 μL / cm²). 2The total volume was controlled at 636 μL / sheet. The control group was treated with anhydrous ethanol only. After treatment, the filter paper was air-dried in a fume hood at 25°C for 5 min to accelerate solvent evaporation. Subsequently, 10 third-instar larvae of tyrosinus were added to each petri dish without food. After 5 days of observation, the pupation data of the larvae were recorded, and each concentration group was repeated 5 times. If the third-instar larvae of tyrosinus did not respond to touch and strong light exposure within 24 hours and failed to pupate successfully after 5 days, the third-instar larvae were considered dead, indicating that the pupation process was inhibited.

[0063] Statistical analysis showed that peppermint essential oil inhibited the pupation toxicity of third-instar larvae of the methcathinone fly by 5 days. 30 3.59 μL / cm 2 IC 50 4.986 μL / cm 2 IC 90 It is 11.127 μL / cm 2 .

[0064] 4. Peppermint essential oil has a localized contact toxicity effect on the emergence inhibition of pupae of milk fly.

[0065] This study optimized the method for testing the local contact toxicity of insect pests, aiming to investigate the local contact inhibitory effect of essential oils on tyrosinus pupae (Gong Qingtao et al., 2021). The experiment was conducted in Piper dishes (Φ90 mm). First, the essential oils were diluted with anhydrous ethanol and evenly dispersed on filter paper (0.5-10 μL / cm). 2 The total volume was controlled at 636 μL / sheet. The control group was treated with anhydrous ethanol only. The treated filter paper was air-dried in a fume hood at 25°C for 5 min to accelerate solvent evaporation. Subsequently, 10 tyrosinus pupae were added to each petri dish without food. Larval pupation data were recorded after 30 days, with each concentration group repeated 5 times. If the tyrosinus pupae showed no color change within 48 h and failed to emerge successfully after 30 days, they were considered dead, indicating that pupal emergence was inhibited.

[0066] Statistical analysis showed that peppermint essential oil inhibited the emergence of pupae of jackfly at a concentration of 1 μL / cm². 2 96% was achieved under the specified conditions at 3 μL / cm 2 This can achieve 100% feathering suppression effect.

[0067] 5. The repellent effect of peppermint essential oil on adult cheese flies.

[0068] This study used a repellency device to evaluate the repellent effect of essential oils on adult tyrosperms (Tian, ​​2023). A 2cm × 2cm filter paper soaked in essential oil was placed at the bottom of the device, and an air pump was used to generate a suitable flow rate to ensure air circulation within the device. Broth was added to the control group, while mixtures of essential oil and broth at different concentrations were added to the test group. An adult tyrosperm was then placed in a Y-shaped tube, and its deflection was recorded after 1 minute. Five replicates were set up for each experiment to ensure the reliability of the results.

[0069] Statistics show that peppermint essential oil has a repellent effect on adult jackflies at a concentration of 1 μL / cm³. 2 Under certain conditions, it reached 43%, while 2 μL / cm 2 It can achieve an 83% repellency effect.

[0070] 6. Fumigation toxicity of peppermint essential oil on adult cheese flies.

[0071] This study used a modified Erlenmeyer flask fumigation method, referencing the method of Chen et al. (2018), to evaluate the fumigation toxicity of essential oils to adult bottling flies. Sealed glass Erlenmeyer flasks with a calibrated volume of 250 mL were used, with an actual effective gas volume of 300 mL. Essential oils (0.5 mL / L of air) were added dropwise onto filter paper (4 cm × 4 cm) and placed under the stopper. The control group used only deionized water. Ten adult bottling flies were placed in each Erlenmeyer flask, and 1.0 ± 0.1 g of marbled ham was provided as food. The experiment was repeated four times at each concentration, and mortality data for adult bottling flies were recorded at 1, 2, 6, 12, 24, and 48 hours. Adult bottling flies were considered dead if they were unable to fly and showed no signs of limb movement.

[0072] Statistics show that peppermint essential oil has a fumigant effect on adult jackflies at a concentration of 0.5 μL / cm³. 2 LT under conditions 50 The effect time reached 7.061 h (0.212-16.052 h), while 1 μL / cm 2 LT under conditions 50 It can reach 0.872h (0.12-2.296h), and has a very strong fumigation effect.

[0073] Example 2

[0074] 1. Preparation of peppermint oil emulsion for controlling ham pests:

[0075] Chitosan was dissolved in a 1% (v / v) aqueous solution of acetic acid (prepared from acetic acid and water) and mixed at 25°C for 4 hours to obtain solution A;

[0076] Solution A was mixed with glycerol and kept at 25°C for 1 hour to obtain solution B;

[0077] Mix solution B, peppermint essential oil, and Tween 80 evenly to obtain a peppermint essential oil emulsion for controlling ham pests.

[0078] The proportions of each component are shown in Table 2.

[0079] Table 2

[0080]

[0081] 2. Preparation and particle size characterization of peppermint essential oil emulsion

[0082] After sampling the prepared emulsion, it was diluted 10 times with deionized water, and the nanoparticle size and dispersion index were measured using a wide dynamic potential and nanoparticle size analyzer (Wang Qiuping et al., 2022).

[0083] The particle size distribution of peppermint essential oil emulsion is as follows: Figure 1 As shown, overall, the average particle size and dispersion index of the emulsion both increased with increasing EO concentration in peppermint (Ding Hongying et al., 2024). At a lower EO concentration of 1% EO+CS, the average particle size of the emulsion was 221.5 nm (PDI = 0.307), while at 5% EO+CS, the average particle size increased to 422 nm (PDI = 0.322). With further increases in concentration, the average particle size of the 10% EO+CS emulsion was 937.7 nm (PDI = 0.352), but the more concentrated relative volume of the particles indicated a more uniform distribution.

[0084] 3. The effect of essential oil emulsions on the taste of ham

[0085] 10.0±0.1g of air-dried ham was placed in an essential oil emulsion and left to stand for 5 minutes, ensuring the ham was fully coated with the emulsion (approximately 200μL / g). After air-drying at 25℃ for 5 minutes in a fume hood, it was fermented in an incubator for 5 days. The incubator conditions were set at 25±1℃ and 70±5% relative humidity. After 5 days, 5.0±0.1g of the sample was weighed and mixed with 40mL of distilled water (37℃), and homogenized at 3000rpm for 60s using a high-speed homogenizer. Then, it was centrifuged at 2000g for 10 minutes at 4℃, and the supernatant was filtered. 10mL of the filtrate was mixed with 50mL of ultrapure water. The taste value was evaluated using the SA402B electronic tongue two-step cleaning method, with a mixed solution of 0.3mM tartaric acid and 30mM potassium chloride as the reference solution (Liue et al., 2022).

[0086] The multifunctional taste perception system (electronic tongue) can simulate human taste perception and can distinguish different taste signals in a short time. Figure 2The study showed the effects of adding different concentrations of essential oil emulsions to dry-cured ham on the sensory scores of the taste sensory system, including sourness, bitterness, astringency, richness, saltiness, umami, aftertaste bitterness, and aftertaste astringency (Liu, 2023). The results showed that, except for the 100% EO+CS group, the differences in sensory scores among the other treatment groups were small. This indicates that adding an appropriate amount of essential oil emulsion during the fermentation process of dry-cured ham does not significantly affect the ham's texture and flavor. However, the 100% EO+CS group showed significantly lower scores for acidity, richness, and aftertaste astringency, which may mean that the addition of high concentrations of pure essential oils has a significant impact on the ham's flavor, altering its original taste and texture. The following section will focus on the effect of essential oil emulsions on the insect-repellent properties of dry-cured ham.

[0087] 4. The effect of essential oil emulsions on the color of ham

[0088] 5.0±0.1g of air-dried ham was placed in an essential oil emulsion for 5 minutes, ensuring the ham surface was fully coated with the emulsion (approximately 200μL / g). It was then air-dried at 25℃ for 5 minutes in a fume hood and fermented in an incubator for 5 days. Incubator conditions were set at 25±1℃ and 70±5% relative humidity. Color was measured using a colorimeter. Each group was repeated three times (Zhang et al., 2024).

[0089] The effect of peppermint essential oil emulsion on the surface color of ham is shown in Table 3. Figure 3 As shown in the figure. By comparison, it was found that the L* (brightness or lightness) value of the control group C and 10% EO+CS showed no significant difference, indicating that at a 10% concentration of peppermint oil, the emulsion had little effect on the brightness of the ham and could maintain its original color. However, the L values ​​of other groups with added emulsion showed certain differences, significantly increasing the brightness of the ham. The a* (redness value) was generally positive, indicating that the color of all meat samples was predominantly red, and there were no significant differences among all groups except the 1% EO+CS group, suggesting that different concentrations of essential oil emulsion had a relatively consistent effect on the redness value of the meat. Regarding the b* (yellowness value), all groups with added emulsion showed significant differences compared to the control group, indicating that the addition of the emulsion led to an increase in the yellowness value of the ham. This may be due to the interaction between the color of the chitosan emulsion itself and the surface of the ham. The color difference value E* is used to measure the difference between two colors. The results showed that the 10% EO+CS group had the lowest E* value, approximately between 2 and 3. This means that the color difference between group C and the 10% EO+CS group was perceptible, but not significant. This indicates that in practical applications, the effect of 10% peppermint oil emulsion on ham color is acceptable and will not significantly affect the appearance of the ham (Zhang et al., 2024).

[0090] The color difference values ​​between different essential oil emulsion treatment groups are shown in Table 3.

[0091] Table 3

[0092]

[0093] 5. The repellent effect of essential oil emulsions on tyrosin fly larvae.

[0094] To verify the repellent effect of essential oil emulsion on tyrosinfly larvae after application to ham, the repellent effect of essential oil emulsion on tyrosinfly larvae was studied. 5.0±0.1g of ham was placed in essential oil emulsion and left to stand for 5 minutes, ensuring the ham was fully coated with the emulsion (approximately 200μL / g). One portion (2.0±0.1g of ham coated with emulsion) served as the test group, while the other portion (ham treated with pure water) served as the control group. Both groups were air-dried at 25℃ for 5 minutes in a fume hood. Twenty tyrosinfly larvae (multiple instars) were then placed at the boundary between the control and test groups, and the larvae's attraction was observed. Records were taken every 12 hours for a period of 48 hours.

[0095] Peppermint essential oil lotion has a repellent effect on tyrosin fly larvae, such as... Figure 4 As shown, a 5% EO+CS concentration emulsion achieved a repellency rate of over 50% within 12 hours, and the repellency rate stabilized at approximately 69.4% after 36 hours. A 10% EO+CS concentration emulsion achieved a repellency rate exceeding 60% within 12 hours, reaching its peak repellency rate (72.2%) at 48 hours. The repellency effect of essential oil emulsions was somewhat lower than that of pure essential oils. Although the repellency effect of essential oil emulsions was lower than that of pure essential oils, this decrease may be related to the physical properties of the emulsion, such as the dispersibility and volatility of essential oils in the emulsion, which may be affected by the emulsion matrix (Yang et al., 2024). However, essential oil emulsions still showed significant repellency effects, indicating that essential oils in emulsion form can still serve as an effective tyrosinfly repellent (Lucia et al., 2021).

[0096] 6. Local contact toxicity of essential oil emulsions to second instar larvae of tyrosinus flies.

[0097] Place 5.0 ± 0.1 g of ham in an essential oil emulsion and let it stand for 5 minutes to coat the ham surface completely with the emulsion (approximately 200 μL / g). Air dry in a fume hood at 25°C for 5 minutes. Add 10 second-instar larvae of cheese flies to the emulsion-coated ham. Observe and record the mortality data of the second-instar larvae after 48 hours. Repeat the experiment 5 times for each concentration. The mortality criteria for second-instar larvae of cheese flies are the same as in Example 1.

[0098] Peppermint essential oil emulsion's local contact toxicity to second instar larvae of tyrosinus flies is as follows: Figure 5As shown in the figure. Experimental results indicate that at a concentration of 1% EO+CS, the mortality rate of the emulsion against second-instar larvae of methcathinone exceeded 20%, a significantly higher effect than group C and the CS emulsion group. This suggests that the CS emulsion had no significant insecticidal effect on second-instar larvae of methcathinone, while the peppermint oil emulsion exhibited significant insecticidal activity. With increasing peppermint oil concentration, the mortality rate of second-instar larvae of methcathinone also increased significantly. Under the condition of 10% EO+CS, the mortality rate of second-instar larvae reached 76%, showing that the peppermint oil emulsion still maintained a strong insecticidal effect. This result further confirms that peppermint oil emulsion can be used as an effective means of insecticidal treatment for dried cured ham (Giuntie et al., 2019).

[0099] 7. The essential oil emulsion exhibits local contact pupation inhibition toxicity against 3rd instar larvae of the tyrosinase.

[0100] 5.0 ± 0.1 g of ham was placed in an essential oil emulsion and left to stand for 5 minutes, ensuring the ham was fully coated with the emulsion (approximately 200 μL / g). The treated ham was then placed in the center of a Piper dish (Φ90 mm) and air-dried at 25°C for 5 minutes in a fume hood. Ten third-instar larvae of tyrosinus were added to the emulsion-coated ham. After 5 days, the pupation data of the third-instar larvae were observed and recorded. Each concentration group was repeated 5 times. The criteria for judging the inhibition of pupation of third-instar larvae of tyrosinus were the same as in Example 1.

[0101] Peppermint essential oil emulsion has a local contact pupation inhibitory toxicity effect on 3rd instar larvae of tyrosinus flies, such as... Figure 6 As shown.

[0102] Experimental data showed that at a concentration of 1% EO+CS, the emulsion inhibited the pupation of third-instar larvae of methcathinone by more than 30%, a significantly higher effect than group C and the CS emulsion group. This indicates that the CS emulsion did not significantly inhibit the pupation process of third-instar larvae of methcathinone, while the addition of peppermint oil significantly enhanced the pupation inhibition toxicity of the emulsion (Erland et al., 2015). With increasing peppermint oil concentration, the local contact pupation inhibition toxicity of the emulsion on third-instar larvae also significantly increased. Under the condition of 10% EO+CS, the pupation inhibition rate of third-instar larvae could reach 60%. Although the inhibition rate of the essential oil emulsion did not reach the effect of pure peppermint oil, it still showed a significant inhibitory effect compared with the control group. The results further confirm that peppermint oil emulsion can be used as an effective means of controlling methcathinone in dried ham (Parichanone et al., 2023).

[0103] 8. The essential oil emulsion inhibits the toxicity of pupae emerging from the larvae of the botfly.

[0104] 5.00±0.01g of ham was placed in an essential oil emulsion and left to stand for 5 minutes, ensuring the ham was fully coated with the emulsion (approximately 200μL / g). The treated ham was then placed in the center of a Piper dish (Φ90mm) and air-dried at 25°C for 5 minutes in a fume hood. Ten tyrosperm pupae were then added to the emulsion-coated ham. After 30 days, the pupation data of the third instar larvae were observed and recorded. Each concentration experiment was repeated 5 times. The criteria for judging the inhibition of tyrosperm pupal emergence were the same as in Example 1.

[0105] Peppermint essential oil emulsion has a local contact effect on inhibiting the emergence of botulism in botulism flies, such as... Figure 7 As shown in the experimental data, group C, the CS emulsion group, and the 1% EO+CS group all failed to exhibit significant pupal emergence inhibition toxicity, indicating that the pupation inhibition effect of low concentrations of peppermint essential oil on jackfly pupae is limited. However, when the concentration was increased to 5% EO+CS, the emulsion significantly reduced the pupal emergence rate of jackfly pupae to below 50%. At a concentration of 10% EO+CS, the pupal emergence rate of jackfly pupae further decreased to 8%. The results indicate that the pupal emergence inhibition effect of peppermint essential oil is reduced after being made into an emulsion, and only in the presence of higher concentrations of peppermint essential oil can the emulsion effectively inhibit the pupal emergence process of jackfly pupae.

[0106] 9. The repellent effect of essential oil emulsions on the oviposition of adult tyrosin flies.

[0107] 5.0 ± 0.1 g of ham was immersed in an essential oil emulsion for 5 minutes to coat the ham surface completely (approximately 200 μL / g). Control group C was simply immersed in water. The treated ham was placed in the center of a Piper dish (Φ90 mm), and 10 adult tyrosinus flies (male:female = 1:1) were added. The dish was sealed with plastic wrap, and a hole was punctured with a 1 mL sterile syringe needle to ensure air circulation. The number of tyrosinus eggs on the ham was recorded after all 10 adult tyrosinus flies had died. Each group was repeated three times.

[0108] Essential oil emulsions can serve as ideal repellents for adult ham fly larvae (Quallsetal., 2020). Experimental results regarding the repellent effect of peppermint essential oil emulsions on adult ham fly oviposition are as follows: Figure 8 and Figure 9 As shown. From Figures 4-5 and Figures 4-6The images of ham surface egg count clearly show a significant difference in the number of adult botfly eggs laid between different essential oil concentration groups. There was no significant difference in egg count between the control group (C) and the CS group, indicating that pure CS emulsion has no significant effect on the oviposition behavior of adult botflies without added essential oil, meaning that the CS emulsion itself does not have a repellent effect. However, the oviposition-repelling effect on adult botflies gradually increased with increasing essential oil concentration. In the 10% EO+CS emulsion, the number of adult botflies laying eggs was only in the single digits, with a repellency rate as high as 99%. Overall, even a 1% EO+CS concentration emulsion can achieve an oviposition-repelling effect of over 50%, indicating that ham coated with essential oil emulsion has a significant repellent effect on adult botflies (Parichanone et al., 2023).

[0109] 10. Fumigation toxicity of essential oil emulsions to adult tyrosin flies.

[0110] 5.0 ± 0.1 g of ham was immersed in an essential oil emulsion for 5 minutes to coat the ham surface completely (approximately 200 μL / g). The treated ham was then placed at the bottom of a calibrated 250 mL Erlenmeyer flask, with the meat wrapped in gauze. The actual effective gas volume of the Erlenmeyer flask was 300 mL. The flask was sealed with a stopper, and the mortality data of adult jackflies were recorded at 1, 2, 6, 12, 24, and 48 hours. Each experiment was repeated four times. The control group used deionized water. The results are shown in Table 4.

[0111] Table 4. Fumigation toxicity of peppermint oil emulsion to adult strata flies.

[0112]

[0113] Example 3

[0114] 1. Prepare a peppermint oil emulsion for controlling ham pests using the method in Example 2, the difference being that citric acid is used as the cosolvent; epoxidized soybean oil is used as the plasticizer; and Span is used as the emulsifier.

[0115] 2. Prepare a peppermint oil emulsion for controlling ham pests using the method in Example 2, the difference being that acetic acid is used as the cosolvent; polyethylene glycol is used as the plasticizer; and gum arabic is used as the emulsifier.

[0116] The test was conducted using the same method as in Example 2, and the results were similar to those in Example 2 with no significant difference. This demonstrates that the present invention, when tested with peppermint essential oil in the form of an emulsion, achieved significant results.

[0117] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A peppermint oil emulsion for controlling pests in ham, characterized in that, It comprises the following components in parts by weight: peppermint oil 1-10%, chitosan 1-3%, aqueous solubilizer 1%, plasticizer 0.5-1.5%, emulsifier 0.5-1.5%, and the balance being water; The preparation method of the peppermint essential oil emulsion for controlling ham pests includes the following steps: 1) Weigh each raw material according to the stated weight proportions; 2) Dissolve chitosan in an aqueous co-solvent solution and mix thoroughly to obtain solution A; 3) Mix solution A with the plasticizer until homogeneous to obtain solution B; 4) Mix solution B, peppermint essential oil, and emulsifier evenly to obtain a peppermint essential oil emulsion for controlling ham pests.

2. The peppermint essential oil emulsion according to claim 1, characterized in that, The co-solvent aqueous solution includes one or more of acetic acid, lactic acid, citric acid, malic acid, ascorbic acid, acetic acid, tartaric acid, and phosphoric acid.

3. The peppermint essential oil emulsion according to claim 1, characterized in that, The plasticizer includes one or more of glycerol, tributyl citrate, acetylated tributyl citrate, epoxidized soybean oil, dehydrated sorbitan fatty acid ester, epoxidized linseed oil, and polyethylene glycol.

4. The peppermint essential oil emulsion according to claim 1, characterized in that, The emulsifier includes one or more of Tween, calcium carbonate, Span, fatty acid salts, sulfate salts, gelatin, and gum arabic.

5. The peppermint essential oil emulsion according to claim 1, characterized in that, In step 2), the mixing temperature is 20-30℃ and the time is 2-6h.

6. The application of the peppermint essential oil emulsion according to claim 1 in the control of pests in ham, characterized in that, The pests affecting ham include cheese flies, carrion mites, and red-necked coconut beetles.

7. The application according to claim 6, characterized in that, The methods of prevention and control include repellency, suppression, contact killing, or fumigation.

8. The application according to claim 6, characterized in that, The stages of pest control for ham include the egg, larva, pupa, and adult stages.

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