A synthetic menthol oil composition and a method for its preparation

Abstract

The present application relates to the technical field of daily chemicals, and particularly discloses a synthetic menthol oil composition and a preparation method thereof, which comprises the following raw materials: fermented mint leaf extract, L-menthol, menthone, oat fermented powder, essential oil fragrance base, non-ionic surfactant, hydroxypropyl-beta-cyclodextrin, fucose-polypeptide microcapsules and composite adjuvant. The preparation method of the composition is as follows: L-menthol, menthone, essential oil fragrance base and non-ionic surfactant are mixed to form an oil phase; deionized water, hydroxypropyl-beta-cyclodextrin and composite adjuvant are mixed to form an aqueous phase; the oil phase is added to the aqueous phase to emulsify and obtain a microemulsion; finally, fermented mint leaf extract, oat fermented powder and fucose-polypeptide microcapsules are added, and homogenization, degassing and sterilization are performed to obtain the composition. The synthetic menthol oil composition prepared by the present application has the advantages of good fragrance locking, high stability, slow release, long-acting and low irritation, and can be applied to the fields of daily chemicals, medicine or food flavor.

Description

Technical Field

[0001] This invention relates to the field of daily chemical products technology, specifically to a synthetic menthol oil composition and its preparation method. Background Technology

[0002] Peppermint oil, a classic volatile plant essential oil, is rich in active ingredients such as L-menthol and menthone. Due to its unique cooling sensation, antibacterial and anti-inflammatory properties, and invigorating effects, it is widely used in medicine, daily chemicals, oral care, and fragrances. However, the yield and quality of natural peppermint oil are greatly affected by natural factors such as climate, origin, and harvesting season. In recent years, synthetic peppermint oil, made by artificially blending high-purity monomeric components, has emerged. However, traditional synthetic peppermint oil still faces many technical bottlenecks in practical applications.

[0003] First, the main active ingredients in synthetic peppermint oil (such as menthol and menthone) are highly volatile and heat-sensitive. During processing, storage, or high-temperature sterilization, their core aroma and cooling components are easily lost or decomposed, resulting in short-lasting fragrance and poor controlled-release effects. Second, menthol and other monomeric components are strongly lipophilic and poorly soluble in water, easily exhibiting layering, precipitation, or crystallization in aqueous systems. Conventional preparation processes often rely on large amounts of chemically synthesized surfactants for solubilization, which not only compromises the product's naturalness but also easily irritates the skin and mucous membranes, limiting its application in high-quality daily chemical or pharmaceutical formulations. Furthermore, single synthetic components lack the support of exogenous synergistic factors such as polysaccharides and flavonoids found in natural plant extracts, resulting in antioxidant and anti-inflammatory bioactivity far inferior to that of natural essential oils.

[0004] Based on the above statements, the present invention provides a synthetic peppermint oil composition and a method for preparing the same. Summary of the Invention

[0005] To address the problems of easy volatility of core components, poor emulsification stability in aqueous systems, strong irritation, and limited bioactivity in traditional synthetic peppermint oil, this invention provides a synthetic peppermint oil composition and its preparation method.

[0006] In a first aspect, the present invention provides a synthetic peppermint oil composition, employing the following technical solution: A synthetic peppermint oil composition comprising the following raw materials in parts by weight: 8-12 parts fermented peppermint leaf extract, 2-4 parts L-menthol, 1-2 parts menthone, 6-12 parts oat baking powder, 10-18 parts essential oil flavoring base, 10-14 parts nonionic surfactant, 4-6 parts hydroxypropyl-β-cyclodextrin, 4-8 parts fucose-peptide microcapsules, 0.4-0.8 parts compound antioxidant, 0.5-1 part compound preservative, and 30-40 parts deionized water.

[0007] Preferably, the fermented peppermint leaf extract is prepared by the following method: After washing fresh peppermint leaves, add deionized water to make a pulp, then add a compound enzyme for enzymatic hydrolysis. After the enzymatic hydrolysis is completed, the enzyme is inactivated, cooled, and then inoculated with Bacillus subtilis for fermentation. After the fermentation is completed, centrifuge, take the supernatant, add polysorbate-20 to the supernatant, stir well, concentrate under reduced pressure, filter, and obtain fermented peppermint leaf extract.

[0008] Preferably, the fermented peppermint leaf extract is prepared by the following specific method: Fresh mint leaves are washed and pulped with deionized water at a mass ratio of 1:8-12 to obtain mint pulp. Then, 0.3-0.5% (by weight) of a compound enzyme is added to the mint pulp, and the mixture is hydrolyzed at 42-48℃ for 1.5-2.5 hours. After hydrolysis, the enzyme is inactivated at 80-85℃ for 10-15 minutes, and then cooled to 35-38℃. Finally, 2-4% (by weight) of Bacillus subtilis (concentration 10%) is inoculated into the mint pulp. 8 -10 10 Ferment (CFU / mL) at 35-38℃ for 20-28 hours; after fermentation, centrifuge at 4500-5500 rpm for 8-12 minutes, collect the supernatant, add polysorbate-20 to the supernatant at a mass ratio of 100:1-2, stir at room temperature at 200-300 rpm for 10-20 minutes, then concentrate under reduced pressure of 0.08-0.095 MPa at 50-58℃ until the solid content is 22-28%, filter through a 100-200 mesh filter to obtain fermented peppermint leaf extract.

[0009] Preferably, the complex enzyme is composed of a neutral protease with an enzyme activity of 10,000-30,000 U / g and a cellulase with an enzyme activity of 10,000-30,000 U / g in a mass ratio of 1:1-3.

[0010] Preferably, the oat baking powder is prepared by the following method: After the oats are crushed and sieved, they are mixed with deionized water to obtain a fermentation substrate. After sterilization and cooling, a compound strain is inoculated for fermentation. After fermentation, the fermentation product is dried, crushed and sieved to obtain oat baking powder.

[0011] Preferably, the oat baking powder is prepared by the following specific method: Oat flour is obtained by pulverizing oats and passing them through a 40-60 mesh sieve. Deionized water is added to the oat flour at a mass ratio of 1:4-6, and the mixture is stirred at 200-300 rpm for 15-25 minutes at room temperature to obtain the fermentation substrate. The fermentation substrate is then sterilized at 115-121℃ for 15-20 minutes, cooled to 35-37℃, and inoculated with a compound microbial culture accounting for 3-5% of the mass of the fermentation substrate. The mixture is then fermented at a constant temperature of 35-37℃ for 36-48 hours. After fermentation, the fermentation product is dried at 55-65℃ until the moisture content is ≤8%, then pulverized and passed through an 80-120 mesh sieve to obtain oat baking powder.

[0012] Preferably, the compound microbial strain consists of *Lactobacillus helveticus* and *Aspergillus oryzae* at an effective viable count ratio of 1-3:1, and the total viable count of the compound microbial strain is 10. 8 -10 10 CFU / mL.

[0013] Preferably, the fucose-peptide microcapsules are prepared by the following method: Soy protein isolate was added to deionized water, stirred evenly, pH was adjusted, and alkaline protease was added for enzymatic hydrolysis. After enzymatic hydrolysis, the enzyme was inactivated, and the supernatant was collected by centrifugation. The supernatant was concentrated through a nanofiltration membrane to obtain a hydrophobic peptide concentrate. The hydrophobic peptide concentrate was mixed with L-fucose and menthol, stirred evenly, and emulsified by high-speed shearing to obtain a promulgated emulsion. The promulgated emulsion was treated with high-pressure microfluidic jet to obtain a nanoemulsion. The nanoemulsion was freeze-dried to obtain fucose-peptide microcapsules.

[0014] Preferably, the fucose-peptide microcapsules are prepared by the following specific method: Add soy protein isolate to deionized water at a mass ratio of 1:25-35, stir at 300-500 rpm for 10-20 min, adjust the pH to 8.0-9.0 with 1 mol / L NaOH solution, add 1.5-2.5% alkaline protease (enzyme activity 50000-150000 U / g) and hydrolyze at 50-55℃ for 3-4 h. After hydrolysis, heat to 85-90℃ to inactivate the enzyme for 10-15 min, centrifuge at 4500-5500 rpm for 10-15 min and collect the supernatant. Concentrate the supernatant through a nanofiltration membrane with a molecular weight cutoff of 1 kDa. The retentate was collected to obtain a hydrophobic peptide concentrate. The hydrophobic peptide concentrate was mixed with L-fucose and menthol at a mass ratio of 10-15:1-4:2-5 and stirred at 45-55℃ and 200-400 rpm for 15-25 min. Then, it was emulsified by high-speed shearing at 8000-12000 rpm for 10-15 min to obtain a proemulsion. The proemulsion was circulated 2-4 times under high pressure microjet at 80-120 MPa to obtain a nanoemulsion. The nanoemulsion was pre-frozen at -80℃ for 6-12 h and then freeze-dried at 10-20 Pa and -50℃ for 18-36 h to obtain fucose-peptide microcapsules.

[0015] Preferably, the essential oil flavoring base is composed of menthol, menthyl acetate, isomenthone, and anethole in a mass ratio of 35-40:25-30:18-22:8-12.

[0016] Preferably, the nonionic surfactant is selected from one or more of PEG-40 hydrogenated castor oil, polysorbate-20, and polysorbate-80.

[0017] Preferably, the composite antioxidant is composed of tea polyphenols and vitamin E acetate in a mass ratio of 1-2:1.

[0018] Preferably, the composite preservative is composed of phenoxyethanol and ethylhexylglycerin in a mass ratio of 8-10:1.

[0019] Secondly, the present invention provides a method for preparing a synthetic peppermint oil composition, employing the following technical solution: A method for preparing a synthetic peppermint oil composition includes the following preparation steps: S1. Mix L-menthol, menthone, essential oil fragrance base and nonionic surfactant, and stir evenly to obtain an oil phase mixture; S2. Mix deionized water, hydroxypropyl-β-cyclodextrin, composite antioxidant and composite preservative, and stir until homogeneous to obtain an aqueous phase; S3. Add the oil phase mixture to the aqueous phase and stir until homogeneous to obtain a microemulsion; S4. Add fermented peppermint leaf extract, oat yeast and fucose-peptide microcapsules to the microemulsion, stir evenly, homogenize, degas under vacuum, sterilize and cool to obtain the synthetic peppermint oil composition.

[0020] Preferably, in step S1, the stirring temperature is 25-35℃, the stirring speed is 300-500 rpm, and the stirring time is 20-30 min.

[0021] Preferably, in step S2, the stirring temperature is 45-55℃, the stirring speed is 400-600 rpm, and the stirring time is 15-25 min.

[0022] Preferably, in step S3, the stirring temperature is 45-55℃, the stirring speed is 600-800 rpm, and the stirring time is 20-40 min.

[0023] Preferably, in step S4, the stirring temperature is 25-35℃, the stirring speed is 400-600rpm, the stirring time is 20-30min; the homogenization pressure is 25-35MPa, the number of homogenizations is 1-3; the negative pressure condition for vacuum degassing is 0.08-0.095MPa, and the vacuum degassing time is 15-25min.

[0024] Thirdly, the present invention provides an application of the above-mentioned synthetic peppermint oil composition in daily chemical products, pharmaceutical preparations or food flavorings.

[0025] In summary, the present invention has the following beneficial effects: 1. In-situ micellar solubilization for efficient aroma locking and activity preservation. Before preparing the concentrated fermented peppermint leaf extract, this invention pre-introduces a surfactant for micelle encapsulation, effectively trapping natural volatile oils and significantly reducing aroma loss during the vacuum concentration process. Combined with subsequent multi-level encapsulation of hydroxypropyl-β-cyclodextrin and fucose-peptide microcapsules, it achieves efficient aroma locking and long-lasting sustained release of the core volatile components.

[0026] 2. Nanoscale self-assembled microcapsules significantly improve system stability. This invention precisely extracts amphiphilic hydrophobic peptides of specific molecular weights, enabling them to self-assemble with L-fucose and menthol into nanoscale microcapsules under high-pressure microfluidic conditions. These microcapsules exhibit high interfacial strength and uniform particle size, effectively preventing the efflux and aggregation of oil phase components, and significantly improving the long-term emulsification stability of the composition in aqueous systems.

[0027] 3. Enhanced biological activity through dual-enzyme co-processing and symbiotic fermentation. In this invention, a neutral protease combined with cellulase is used to degrade the peppermint cell wall, allowing for the full release of endogenous active ingredients. Simultaneously, Lactobacillus helveticus and Aspergillus oryzae are used to symbiotically ferment oats, producing abundant free amino acids, β-glucan, and organic acids. The synergistic effect among these active ingredients overcomes the limitations of traditional peppermint oil's single-effect properties, endowing the product with excellent soothing properties and antioxidant activity.

[0028] 4. Synergistic microemulsification process to construct an ultra-stable clarification system This invention precisely combines nonionic surfactants and hydroxypropyl-β-cyclodextrin, and under precise temperature control and gradient shear / high pressure homogenization, completely solubilizes and uniformly disperses the highly hydrophobic oil-phase flavoring base in the aqueous phase, forming a thermodynamically stable microemulsion system. This ensures that the product remains clear and transparent without separation even after long-term storage or high and low temperature cycling.

[0029] 5. Multiple sustained-release barriers significantly reduce mucosal irritation. This invention constructs a multi-level encapsulation barrier through micellar solubilization, cyclodextrin inclusion, and nanocapsule formation, enabling the stepwise and slow release of irritating components such as L-menthol, effectively desensitizing the instantaneous sensation of intense cold. Combined with the natural anti-allergic and repairing effects of oat fermentation products, this significantly broadens the product's safe application window in daily chemical products, pharmaceuticals, and food flavorings for sensitive skin. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0031] 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.

[0032] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available products.

[0033] Polysorbate-20 was purchased from Hubei Mingya New Material Technology Co., Ltd. PEG-40 hydrogenated castor oil, Dalian Meilun Biotechnology Co., Ltd. Bacillus subtilis was purchased from Shanghai Preservation Microbiology Co., Ltd., accession number: SMHCC D51202; Lactobacillus helveticus was purchased from Wuhan Gray Algae Biotechnology Co., Ltd., product number: HZB118100; Aspergillus oryzae was purchased from Wuhan Gray Algae Biotechnology Co., Ltd., product number: HZB229218.

[0034] Example 1 A synthetic peppermint oil composition comprising the following raw materials in parts by weight: 8 parts fermented peppermint leaf extract, 2 parts L-menthol, 1 part menthone, 6 parts oat baking powder, 10 parts essential oil flavoring base, 10 parts nonionic surfactant, 4 parts hydroxypropyl-β-cyclodextrin, 4 parts fucose-peptide microcapsules, 0.4 parts compound antioxidant, 0.5 parts compound preservative, and 30 parts deionized water.

[0035] The fermented peppermint leaf extract is prepared by the following specific method: Fresh mint leaves were washed and pulped with deionized water at a mass ratio of 1:8 to obtain mint pulp. Then, a compound enzyme (composed of a neutral protease with an activity of 10000 U / g and a cellulase with an activity of 10000 U / g, in a mass ratio of 1:1) was added at 0.3% of the mint pulp mass. Enzymatic hydrolysis was carried out at 42℃ for 1.5 hours. After hydrolysis, the temperature was raised to 80℃ for 10 minutes to inactivate the enzyme, and then cooled to 35℃. Finally, 2% of Bacillus subtilis (concentration of 10%) was inoculated into the mint pulp. 8 The extract was fermented at 35°C for 20 hours (CFU / mL). After fermentation, the extract was centrifuged at 4500 rpm for 8 minutes, and the supernatant was collected. Polysorbate-20 was added to the supernatant at a mass ratio of 100:1. The mixture was stirred at 200 rpm for 10 minutes at room temperature, and then concentrated under reduced pressure of 0.08 MPa at 50°C until the solid content was 22%. The extract was then filtered through a 100-mesh filter to obtain the fermented peppermint leaf extract.

[0036] Oat baking powder is prepared by the following specific methods: Oat flour was obtained by pulverizing oats through a 40-mesh sieve. Deionized water was added to the oat flour at a mass ratio of 1:4, and the mixture was stirred at 200 rpm for 15 minutes at room temperature to obtain the fermentation substrate. The fermentation substrate was sterilized at 115℃ for 15 minutes, cooled to 35℃, and inoculated with a 3% (by weight of) compound microbial culture (composed of *Lactobacillus helveticus* and *Aspergillus oryzae* at a viable viable count ratio of 1:1, with a total viable count of 10). 8 The product was fermented at 35°C for 36 hours (CFU / mL). After fermentation, the product was dried at 55°C until the moisture content was 6%, then pulverized and passed through an 80-mesh sieve to obtain oat baking powder.

[0037] Fucose-peptide microcapsules were prepared by the following specific method: Soy protein isolate was added to deionized water at a mass ratio of 1:25 and stirred at 300 rpm for 10 min. The pH was adjusted to 8.0 with 1 mol / L NaOH solution. Alkaline protease (enzyme activity 50000 U / g) was added at 1.5% of the soy protein isolate mass, and the mixture was hydrolyzed at 50℃ for 3 h. After hydrolysis, the temperature was raised to 85℃ to inactivate the enzyme for 10 min, and the mixture was centrifuged at 4500 rpm for 10 min to collect the supernatant. The supernatant was then concentrated using a nanofiltration membrane with a molecular weight cutoff of 1 kDa. The retentate was collected to obtain a hydrophobic peptide concentrate. The hydrophobic peptide concentrate was mixed with L-fucose and menthol at a mass ratio of 10:1:2 and stirred at 45℃ and 200rpm for 15min. Then, it was emulsified by high-speed shearing at 8000rpm for 10min to obtain a proemulsion. The proemulsion was circulated twice under high pressure microfluidic jet at 80MPa to obtain a nanoemulsion. The nanoemulsion was pre-frozen at -80℃ for 6h and then freeze-dried at 10Pa and -50℃ for 18h to obtain fucose-peptide microcapsules.

[0038] The essential oil fragrance base is composed of menthol furan, menthyl acetate, isomenthone, and anethole in a mass ratio of 35:25:18:8.

[0039] The nonionic surfactant is PEG-40 hydrogenated castor oil.

[0040] The compound antioxidant consists of tea polyphenols and vitamin E acetate in a 1:1 mass ratio.

[0041] The compound preservative consists of phenoxyethanol and ethylhexylglycerin in a mass ratio of 8:1.

[0042] A method for preparing a synthetic peppermint oil composition includes the following preparation steps: S1. Mix L-menthol, menthone, essential oil fragrance base and nonionic surfactant, and stir at 25°C and 300 rpm for 20 min to obtain an oil phase mixture; S2. Mix deionized water, hydroxypropyl-β-cyclodextrin, composite antioxidant and composite preservative, and stir at 45℃ and 400rpm for 15min to obtain the aqueous phase; S3. Add the oil phase mixture to the aqueous phase and stir at 45°C and 600 rpm for 20 min to obtain a microemulsion; S4. Add fermented peppermint leaf extract, oat yeast and fucose-peptide microcapsules to the microemulsion, stir at 25°C and 400 rpm for 20 min, homogenize once at 25 MPa, degas at 0.08 MPa for 15 min, sterilize at 90°C for 20 min, and cool to room temperature to obtain the synthetic peppermint oil composition.

[0043] Example 2 A synthetic peppermint oil composition comprising the following raw materials in parts by weight: 10 parts fermented peppermint leaf extract, 3 parts L-menthol, 1.5 parts menthone, 9 parts oat baking powder, 14 parts essential oil flavoring base, 12 parts nonionic surfactant, 5 parts hydroxypropyl-β-cyclodextrin, 6 parts fucose-peptide microcapsules, 0.6 parts compound antioxidant, 0.75 parts compound preservative, and 35 parts deionized water.

[0044] The fermented peppermint leaf extract is prepared by the following specific method: Fresh mint leaves were washed and pulped with deionized water at a mass ratio of 1:10 to obtain mint pulp. Then, a compound enzyme (composed of a neutral protease with an activity of 20000 U / g and a cellulase with an activity of 20000 U / g, in a mass ratio of 1:2) was added at 0.4% of the mint pulp mass. Enzymatic hydrolysis was carried out at 45℃ for 2 hours. After hydrolysis, the temperature was raised to 82℃ for 12 minutes to inactivate the enzyme, and then cooled to 36℃. Finally, 3% of Bacillus subtilis (concentration of 10) was inoculated into the mint pulp. 9 The extract was fermented at 37℃ for 24 hours (CFU / mL). After fermentation, the extract was centrifuged at 5000 rpm for 10 minutes, and the supernatant was collected. Polysorbate-20 was added to the supernatant at a mass ratio of 100:1.5. The mixture was stirred at 250 rpm for 15 minutes at room temperature, and then concentrated under reduced pressure of 0.085 MPa at 54℃ until the solid content was 25%. The extract was then filtered through a 150-mesh filter to obtain the fermented peppermint leaf extract.

[0045] Oat baking powder is prepared by the following specific methods: Oat flour was obtained by pulverizing oats through a 50-mesh sieve. Deionized water was added to the oat flour at a mass ratio of 1:5, and the mixture was stirred at 250 rpm for 20 minutes at room temperature to obtain the fermentation substrate. The fermentation substrate was sterilized at 120℃ for 18 minutes, cooled to 36℃, and inoculated with a 4% (by weight of) a compound microbial culture (composed of *Lactobacillus helveticus* and *Aspergillus oryzae* at a viable viable count ratio of 2:1, with a total viable count of 10). 9 The product was fermented at 36℃ for 42 hours (CFU / mL). After fermentation, the fermentation product was dried at 60℃ until the moisture content was 6%, then crushed and passed through a 100-mesh sieve to obtain oat baking powder.

[0046] Fucose-peptide microcapsules were prepared by the following specific method: Soy protein isolate was added to deionized water at a mass ratio of 1:30 and stirred at 400 rpm for 15 min. The pH was adjusted to 8.5 with 1 mol / L NaOH solution. Alkaline protease (enzyme activity 100,000 U / g) was added at 2% of the soy protein isolate mass, and the mixture was hydrolyzed at 52℃ for 3.5 h. After hydrolysis, the temperature was raised to 88℃ for 12 min to inactivate the enzyme. The supernatant was collected by centrifugation at 5000 rpm for 12 min. The supernatant was then concentrated using a nanofiltration membrane with a molecular weight cutoff of 1 kDa. The retentate was collected to obtain a hydrophobic peptide concentrate. The hydrophobic peptide concentrate was mixed with L-fucose and menthol at a mass ratio of 12:2:4 and stirred at 50°C and 300 rpm for 20 min. Then, it was emulsified by high-speed shearing at 10000 rpm for 12 min to obtain a proemulsion. The proemulsion was circulated three times under high pressure microfluidic jet at 100 MPa to obtain a nanoemulsion. The nanoemulsion was pre-frozen at -80°C for 9 h and then freeze-dried at 15 Pa and -50°C for 24 h to obtain fucose-peptide microcapsules.

[0047] The essential oil fragrance base is composed of menthol, menthyl acetate, isomenthone, and anethole in a mass ratio of 37:27:20:10.

[0048] The nonionic surfactant is polysorbate-20.

[0049] The compound antioxidant is composed of tea polyphenols and vitamin E acetate in a mass ratio of 1.5:1.

[0050] The compound preservative consists of phenoxyethanol and ethylhexylglycerin in a mass ratio of 9:1.

[0051] A method for preparing a synthetic peppermint oil composition includes the following preparation steps: S1. Mix L-menthol, menthone, essential oil fragrance base and nonionic surfactant, and stir at 30°C and 400 rpm for 25 min to obtain an oil phase mixture; S2. Mix deionized water, hydroxypropyl-β-cyclodextrin, composite antioxidant and composite preservative, and stir at 50°C and 500 rpm for 20 min to obtain an aqueous phase; S3. Add the oil phase mixture to the aqueous phase and stir at 50°C and 700 rpm for 30 min to obtain a microemulsion; S4. Add fermented peppermint leaf extract, oat yeast and fucose-peptide microcapsules to the microemulsion, stir at 30°C and 500 rpm for 25 min, homogenize twice at 30 MPa, degas under vacuum at 0.085 MPa for 17 min, heat to 95°C for 25 min for sterilization, and cool to room temperature to obtain the synthetic peppermint oil composition.

[0052] Example 3 A synthetic peppermint oil composition comprising the following raw materials in parts by weight: 12 parts fermented peppermint leaf extract, 4 parts L-menthol, 2 parts menthone, 12 parts oat baking powder, 18 parts essential oil flavoring base, 14 parts nonionic surfactant, 6 parts hydroxypropyl-β-cyclodextrin, 8 parts fucose-peptide microcapsules, 0.8 parts compound antioxidant, 1 part compound preservative, and 40 parts deionized water.

[0053] The fermented peppermint leaf extract is prepared by the following specific method: Fresh mint leaves were washed and pulped with deionized water at a mass ratio of 1:12 to obtain mint pulp. Then, a compound enzyme (composed of a neutral protease with an activity of 30,000 U / g and a cellulase with an activity of 30,000 U / g, in a mass ratio of 1:3) was added at 0.5% of the mint pulp mass. Enzymatic hydrolysis was carried out at 48℃ for 2.5 hours. After hydrolysis, the temperature was raised to 85℃ for 15 minutes to inactivate the enzyme, and then cooled to 38℃. Finally, 4% of the mint pulp mass was inoculated with Bacillus subtilis (concentration of 10...). 10 The extract was fermented at 38℃ for 28 hours (CFU / mL). After fermentation, the extract was centrifuged at 5500 rpm for 12 minutes, and the supernatant was collected. Polysorbate-20 was added to the supernatant at a mass ratio of 100:2. The mixture was stirred at 300 rpm for 20 minutes at room temperature, and then concentrated under reduced pressure of 0.095 MPa at 58℃ until the solid content was 28%. The extract was then filtered through a 200-mesh filter to obtain the fermented peppermint leaf extract.

[0054] Oat baking powder is prepared by the following specific methods: Oat flour was obtained by pulverizing oats through a 60-mesh sieve. Deionized water was added to the oat flour at a mass ratio of 1:6, and the mixture was stirred at 300 rpm for 25 minutes at room temperature to obtain the fermentation substrate. The fermentation substrate was sterilized at 121℃ for 20 minutes, cooled to 37℃, and inoculated with a 5% (by weight of) a compound microbial culture (composed of *Lactobacillus helveticus* and *Aspergillus oryzae* at a viable viable count ratio of 3:1, with a total viable count of 10). 10 The product was fermented at 37°C for 48 hours (CFU / mL). After fermentation, the product was dried at 65°C until the moisture content was 6%, then pulverized and passed through a 120-mesh sieve to obtain oat baking powder.

[0055] Fucose-peptide microcapsules were prepared by the following specific method: Soy protein isolate was added to deionized water at a mass ratio of 1:35 and stirred at 500 rpm for 20 min. The pH was adjusted to 9.0 with 1 mol / L NaOH solution. Alkaline protease (enzyme activity 150,000 U / g) was added at 2.5% of the soy protein isolate mass, and the mixture was hydrolyzed at 55℃ for 4 h. After hydrolysis, the temperature was raised to 90℃ to inactivate the enzyme for 15 min, and the mixture was centrifuged at 5500 rpm for 15 min to collect the supernatant. The supernatant was then concentrated and separated using a nanofiltration membrane with a molecular weight cutoff of 1 kDa. The retentate was collected to obtain a hydrophobic peptide concentrate. The hydrophobic peptide concentrate was mixed with L-fucose and menthol at a mass ratio of 15:4:5 and stirred at 55℃ and 400rpm for 25min. Then, it was emulsified by high-speed shearing at 12000rpm for 15min to obtain a proemulsion. The proemulsion was circulated 4 times under high pressure microjet at 120MPa to obtain a nanoemulsion. The nanoemulsion was pre-frozen at -80℃ for 12h and then freeze-dried at 20Pa and -50℃ for 36h to obtain fucose-peptide microcapsules.

[0056] The essential oil fragrance base is composed of menthol, menthyl acetate, isomenthone, and anethole in a mass ratio of 40:30:22:12.

[0057] The nonionic surfactant is polysorbate-80.

[0058] The compound antioxidant is composed of tea polyphenols and vitamin E acetate in a mass ratio of 2:1.

[0059] The compound preservative consists of phenoxyethanol and ethylhexylglycerin in a mass ratio of 10:1.

[0060] A method for preparing a synthetic peppermint oil composition includes the following preparation steps: S1. Mix L-menthol, menthone, essential oil fragrance base and nonionic surfactant, and stir at 35°C and 500 rpm for 30 min to obtain an oil phase mixture; S2. Mix deionized water, hydroxypropyl-β-cyclodextrin, composite antioxidant and composite preservative, and stir at 55℃ and 600rpm for 25min to obtain the aqueous phase; S3. Add the oil phase mixture to the aqueous phase and stir at 55°C and 800 rpm for 40 min to obtain a microemulsion; S4. Add fermented peppermint leaf extract, oat yeast and fucose-peptide microcapsules to the microemulsion, stir at 35°C and 600 rpm for 30 min, homogenize three times at 35 MPa, degas at 0.095 MPa for 20 min, sterilize at 100°C for 30 min, and cool to room temperature to obtain the synthetic peppermint oil composition.

[0061] Comparative Example 1 This comparative example provides a synthetic peppermint oil composition and its preparation method. The only difference from Example 2 is that the fermented peppermint leaf extract is replaced with an equal mass of ordinary peppermint leaf extract; the other raw material types, amounts, and preparation process parameters are completely consistent with Example 2.

[0062] Specifically: Common peppermint leaf extract is prepared by the following specific method: Fresh peppermint leaves were washed and pulped with deionized water at a mass ratio of 1:10 to obtain peppermint pulp. The peppermint pulp was centrifuged at 5000 rpm for 10 min, and the supernatant was collected. Polysorbate-20 was added to the supernatant at a mass ratio of 100:1.5. The mixture was stirred at 250 rpm for 15 min at room temperature, and then concentrated under reduced pressure of 0.085 MPa at 54 °C until the solid content was 25%. The extract was then filtered through a 150-mesh filter to obtain ordinary peppermint leaf extract.

[0063] Comparative Example 2 This comparative example provides a synthetic peppermint oil composition and its preparation method. The only difference from Example 2 is that ordinary oat flour is used to replace oat baking powder by the same mass; the other raw material types, amounts and preparation process parameters are completely consistent with Example 2.

[0064] Specifically: Ordinary oat flour is produced through the following specific methods: Oat flour is pulverized through a 50-mesh sieve, dried at 60°C until the moisture content is 6%, then pulverized and sieved through a 100-mesh sieve to obtain ordinary oat flour.

[0065] Comparative Example 3 This comparative example provides a synthetic peppermint oil composition and its preparation method. The only difference from Example 2 is that fucose-peptide microcapsules are replaced with peptide microcapsules of equal mass; the other raw material types, amounts, and preparation process parameters are completely consistent with Example 2.

[0066] Specifically: Peptide microcapsules were prepared by the following specific methods: Soy protein isolate was added to deionized water at a mass ratio of 1:30 and stirred at 400 rpm for 15 min. The pH was adjusted to 8.5 with 1 mol / L NaOH solution. Alkaline protease (enzyme activity 100,000 U / g) was added at 2% of the soy protein isolate mass, and the mixture was hydrolyzed at 52℃ for 3.5 h. After hydrolysis, the temperature was raised to 88℃ for 12 min to inactivate the enzyme, and the mixture was centrifuged at 5000 rpm for 12 min to collect the supernatant. The supernatant was then subjected to a molecular weight cutoff of 1 kDa. The hydrophobic peptide concentrate was obtained by nanofiltration membrane concentration and separation, and the retentate was collected. The hydrophobic peptide concentrate was mixed with menthol at a mass ratio of 12:6 and stirred at 300 rpm for 20 min at 50 °C. Then, it was emulsified by high-speed shearing at 10000 rpm for 12 min to obtain the proemulsion. The proemulsion was circulated three times under high pressure microjet at 100 MPa to obtain the nanoemulsion. The nanoemulsion was pre-frozen at -80 °C for 9 h and then freeze-dried at -50 °C for 24 h at 15 Pa to obtain the peptide microcapsules.

[0067] Comparative Example 4 This comparative example provides a synthetic peppermint oil composition and its preparation method. The only difference from Example 2 is that, in the preparation process of fermented peppermint leaf extract, only neutral protease is used for enzymatic hydrolysis, and cellulase is not used; the other raw material types, amounts, and preparation process parameters are completely consistent with those of Example 2.

[0068] Specifically: Fermented peppermint leaf extract is prepared by the following specific method: Fresh mint leaves were washed and pulped with deionized water at a mass ratio of 1:10 to obtain mint pulp. Then, 0.4% (by weight of the mint pulp) of neutral protease (enzyme activity 20000 U / g) was added, and the mixture was hydrolyzed at 45℃ for 2 hours. After hydrolysis, the temperature was raised to 82℃ for 12 minutes to inactivate the enzyme, and then cooled to 36℃. Finally, 3% (by weight of the mint pulp) of Bacillus subtilis (concentration 10) was inoculated. 9 The extract was fermented at 37℃ for 24 hours (CFU / mL). After fermentation, the extract was centrifuged at 5000 rpm for 10 minutes, and the supernatant was collected. Polysorbate-20 was added to the supernatant at a mass ratio of 100:1.5. The mixture was stirred at 250 rpm for 15 minutes at room temperature, and then concentrated under reduced pressure of 0.085 MPa at 54℃ until the solid content was 25%. The extract was then filtered through a 150-mesh filter to obtain the fermented peppermint leaf extract.

[0069] Comparative Example 5 This comparative example provides a synthetic peppermint oil composition and its preparation method. The only difference from Example 2 is that in the preparation process of fermented peppermint leaf extract, only cellulase is used for enzymatic hydrolysis, and neutral protease is not used; the other raw material types, amounts and preparation process parameters are completely consistent with Example 2.

[0070] Specifically: Fermented peppermint leaf extract is prepared by the following specific method: Fresh mint leaves were washed and pulped with deionized water at a mass ratio of 1:10 to obtain mint pulp. Then, 0.4% (by weight of the mint pulp) of cellulase (enzyme activity 20000 U / g) was added, and the mixture was enzymatically hydrolyzed at 45℃ for 2 hours. After hydrolysis, the temperature was raised to 82℃ for 12 minutes to inactivate the enzyme, and then cooled to 36℃. Finally, 3% (by weight of the mint pulp) of Bacillus subtilis (concentration 10) was inoculated. 9 The extract was fermented at 37℃ for 24 hours (CFU / mL). After fermentation, the extract was centrifuged at 5000 rpm for 10 minutes, and the supernatant was collected. Polysorbate-20 was added to the supernatant at a mass ratio of 100:1.5. The mixture was stirred at 250 rpm for 15 minutes at room temperature, and then concentrated under reduced pressure of 0.085 MPa at 54℃ until the solid content was 25%. The extract was then filtered through a 150-mesh filter to obtain the fermented peppermint leaf extract.

[0071] Comparative Example 6 This comparative example provides a synthetic peppermint oil composition and its preparation method. The only difference from Example 2 is that only Lactobacillus helveticus is used for fermentation in the preparation of oat yeast, and Aspergillus oryzae is not used. The other raw material types, amounts and preparation process parameters are completely consistent with those of Example 2.

[0072] Specifically: Oat baking powder is prepared by the following specific methods: Oat flour was obtained by pulverizing oats through a 50-mesh sieve. Deionized water was added to the oat flour at a mass ratio of 1:5, and the mixture was stirred at 250 rpm for 20 minutes at room temperature to obtain the fermentation substrate. The fermentation substrate was sterilized at 120°C for 18 minutes, cooled to 36°C, and inoculated with 4% (4% by mass) of *Lactobacillus helveticus* (concentration 10). 9 The product was fermented at 36℃ for 42 hours (CFU / mL). After fermentation, the fermentation product was dried at 60℃ until the moisture content was 6%, then crushed and passed through a 100-mesh sieve to obtain oat baking powder.

[0073] Comparative Example 7 This comparative example provides a synthetic peppermint oil composition and its preparation method. The only difference from Example 2 is that, in the preparation of oat yeast, only Aspergillus oryzae is used for fermentation, and Lactobacillus helveticus is not used; the other raw material types, amounts and preparation process parameters are completely consistent with those of Example 2.

[0074] Specifically: Oat baking powder is prepared by the following specific methods: Oat flour was obtained by pulverizing oats through a 50-mesh sieve. Deionized water was added to the oat flour at a mass ratio of 1:5, and the mixture was stirred at 250 rpm for 20 minutes at room temperature to obtain the fermentation substrate. The fermentation substrate was sterilized at 120°C for 18 minutes, cooled to 36°C, and inoculated with 4% Aspergillus oryzae (concentration 10%) by weight of the fermentation substrate. 9 The product was fermented at 36℃ for 42 hours (CFU / mL). After fermentation, the fermentation product was dried at 60℃ until the moisture content was 6%, then crushed and passed through a 100-mesh sieve to obtain oat baking powder.

[0075] Performance testing 1. Detection Object Synthetic peppermint oil compositions prepared in Examples 1-3 and Comparative Examples 1-7.

[0076] 2. Testing Methods (1) Appearance and high and low temperature emulsification stability test Stability under static and centrifugal conditions: Take 10 mL of each sample and place it in a transparent glass bottle, seal it, and let it stand at room temperature (25℃) for 30 days. Record whether layering, turbidity, or precipitation occurs. Take another 5 mL of each sample and centrifuge it at 4000 rpm for 30 min to observe whether layering occurs.

[0077] High and low temperature cycling stability: Each group of samples was first frozen in a -15℃ freezer for 24 hours, then removed and brought to room temperature, and immediately transferred to a 45℃ constant temperature oven for 24 hours. This constitutes one cycle, and a total of 3 cycles were repeated. The appearance of each group of samples was observed after the cycling was completed.

[0078] (2) Determination of fragrance retention and volatile oil residue (headspace GC-MS method) Test method: Quantitative determination was performed using the open-top evaporation method combined with gas chromatography-mass spectrometry (HS-GC-MS): 2.0 g of each sample was accurately weighed and placed in a 20 mL sterile headspace vial, which was then placed in a constant temperature oven at 37 °C and left to stand open for 48 h. The headspace vials were then capped and sealed before (0 h) and after 48 h.

[0079] Measurement conditions: headspace heating equilibrium temperature 80℃, equilibrium time 30 min; chromatographic column HP-5MS; peak area of ​​characteristic aroma components above the sample: L-menthol and menthone was quantitatively analyzed using a high efficiency analytical system.

[0080] The calculation formula is: Residual rate of characteristic volatile components (%) = (characteristic peak area after 48 hours of open storage / characteristic peak area after 0 hours of open storage) × 100%.

[0081] (3) Evaluation of sustained-release and long-lasting cooling sensation (sensory evaluation) Personnel selection: Select 10 professional sensory evaluators (half male and half female) who have undergone standardized training.

[0082] Test method: Take 0.2g of each sample and apply it evenly to a 3cm×3cm area on the inner forearm of the evaluator. Taking the moment of application as time 0, at 5min, 15min, 30min, 60min, 120min and 180min after application, the evaluator quantifies the intensity of the cooling sensation on the local skin (0-10 points: 0 points is no sensation, 10 points is extremely cold stimulation).

[0083] Evaluation indicators: Record the onset time (the time when the score reaches 3 points) and the duration of the cooling sensation (the time when the score remains greater than 1 point).

[0084] (4) Human skin irritation test (closed patch test) Test method: Thirty volunteers with healthy skin were selected. Each sample was diluted with deionized water to a menthol content of 0.5%. A closed-cell skin patch test kit was used. 0.02 mL of the test solution was added to the patch test chamber and applied to the flexor surface of the volunteer's forearm. The patch was left on for 24 hours before being removed.

[0085] Results observation: Skin reactions (erythema, edema, etc.) at the application site were observed by a professional dermatologist at 1 hour and 24 hours after the patch was removed, and were scored according to the standard.

[0086] Scoring criteria: 0 points for no irritation; 1 point for mild erythema (barely visible); 2 points for obvious erythema (clear borders); 3 points for severe erythema accompanied by edema.

[0087] 3. Statistical processing methods All experiments were performed in triplicate, and results are expressed as mean ± standard deviation. One-way ANOVA was used for comparisons between groups, and a p-value < 0.05 was considered statistically significant.

[0088] 4. Test Results and Analysis The specific test results are shown in Table 1.

[0089] Table 1 Performance test results of the synthetic peppermint oil composition

[0090] As shown in Table 1, the synthetic peppermint oil compositions prepared in Examples 1-3 all exhibited excellent performance in terms of appearance stability, volatile oil residue, sustained-release cooling effect, and skin irritation, with Example 2 showing the best overall performance.

[0091] Compared to Example 2, Comparative Example 1 used ordinary peppermint leaf extract without enzymatic hydrolysis and fermentation. Its L-menthol and menthone residue rates were significantly reduced, the duration of the cooling sensation was significantly shortened, and the skin irritation score was increased. This indicates that the combined enzymatic hydrolysis and Bacillus subtilis fermentation treatment not only significantly improved the aroma-locking ability of the volatile oils but also effectively reduced the product's irritation.

[0092] Compared to Example 2, Comparative Example 2 used unfermented ordinary oat flour, resulting in a decrease in volatile oil residue and duration of cooling sensation, as well as an increase in skin irritation score. This indicates that the active metabolites produced by the symbiotic fermentation of oats by *Lactobacillus helveticus* and *Aspergillus oryzae* play a key role in enhancing the product's antioxidant activity and soothing and anti-allergic effects.

[0093] Compared to Example 2, Comparative Example 3 used peptide microcapsules without L-fucose. Upon centrifugation, oil separation occurred, and after high and low temperature cycling, complete demulsification and layering were achieved, significantly reducing the residual volatile oil, shortening the duration of the cooling sensation by nearly half, and significantly increasing the skin irritation score. This indicates that the introduction of L-fucose enhances the interfacial membrane strength and aqueous dispersion stability of the microcapsule, and is a core factor in ensuring long-term emulsification stability and achieving long-lasting sustained release.

[0094] Compared with Example 2, Comparative Example 4, which used only neutral protease for enzymatic hydrolysis, and Comparative Example 5, which used only cellulase for enzymatic hydrolysis, showed a significant decrease in the residual volatile oil and a weakened aroma-locking effect. This confirms that the combined use of neutral protease and cellulase has a synergistic effect on cell wall disruption and volatile oil release in peppermint leaves.

[0095] Compared to Example 2, Comparative Example 6, which fermented oats using only *Lactobacillus helveticus*, and Comparative Example 7, which fermented oats using only *Aspergillus oryzae*, showed a decrease in volatile oil residue, duration of cooling sensation, and skin irritation score. This indicates that the symbiotic fermentation system formed by *Aspergillus oryzae* and *Lactobacillus helveticus* is superior to single-strain fermentation in terms of metabolite diversity and functional activity.

[0096] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A synthetic peppermint oil composition, characterized in that, The ingredients include the following parts by weight: 8-12 parts fermented peppermint leaf extract, 2-4 parts L-menthol, 1-2 parts menthone, 6-12 parts oat baking powder, 10-18 parts essential oil flavoring base, 10-14 parts nonionic surfactant, 4-6 parts hydroxypropyl-β-cyclodextrin, 4-8 parts fucose-peptide microcapsules, 0.4-0.8 parts compound antioxidant, 0.5-1 part compound preservative, and 30-40 parts deionized water.

2. The synthetic peppermint oil composition according to claim 1, characterized in that, The fermented peppermint leaf extract was prepared by the following method: After washing fresh peppermint leaves, add deionized water to make a pulp, then add a compound enzyme for enzymatic hydrolysis. After the enzymatic hydrolysis is completed, the enzyme is inactivated, cooled, and then inoculated with Bacillus subtilis for fermentation. After the fermentation is completed, centrifuge, take the supernatant, add polysorbate-20 to the supernatant, stir well, concentrate under reduced pressure, filter, and obtain fermented peppermint leaf extract.

3. The synthetic peppermint oil composition according to claim 2, characterized in that, The complex enzyme is composed of a neutral protease with an enzyme activity of 10,000-30,000 U / g and a cellulase with an enzyme activity of 10,000-30,000 U / g in a mass ratio of 1:1-3.

4. The synthetic peppermint oil composition according to claim 1, characterized in that, The oat baking powder is prepared by the following method: After the oats are crushed and sieved, they are mixed with deionized water to obtain a fermentation substrate. After sterilization and cooling, a compound strain is inoculated for fermentation. After fermentation, the fermentation product is dried, crushed and sieved to obtain oat baking powder.

5. The synthetic peppermint oil composition according to claim 4, characterized in that, The compound microbial strain consists of *Lactobacillus helveticus* and *Aspergillus oryzae* at a viable viable count ratio of 1-3:1, and the total viable count of the compound microbial strain is 10. 8 -10 10 CFU / mL.

6. The synthetic peppermint oil composition according to claim 1, characterized in that, The fucose-peptide microcapsules were prepared by the following method: Soy protein isolate was added to deionized water, stirred evenly, pH was adjusted, and alkaline protease was added for enzymatic hydrolysis. After enzymatic hydrolysis, the enzyme was inactivated, and the supernatant was collected by centrifugation. The supernatant was concentrated through a nanofiltration membrane to obtain a hydrophobic peptide concentrate. The hydrophobic peptide concentrate was mixed with L-fucose and menthol, stirred evenly, and emulsified by high-speed shearing to obtain a promulgated emulsion. The promulgated emulsion was treated with high-pressure microfluidic jet to obtain a nanoemulsion. The nanoemulsion was freeze-dried to obtain fucose-peptide microcapsules.

7. The synthetic peppermint oil composition according to claim 1, characterized in that, The essential oil flavoring base is composed of menthol, menthyl acetate, isomenthone, and anethole in a mass ratio of 35-40:25-30:18-22:8-12.

8. The synthetic peppermint oil composition according to claim 1, characterized in that, The composite preservative is composed of phenoxyethanol and ethylhexylglycerin in a mass ratio of 8-10:

1.

9. A method for preparing a synthetic peppermint oil composition according to any one of claims 1-8, characterized in that, The preparation steps include the following: S1. Mix L-menthol, menthone, essential oil fragrance base and nonionic surfactant, and stir evenly to obtain an oil phase mixture; S2. Mix deionized water, hydroxypropyl-β-cyclodextrin, composite antioxidant and composite preservative, and stir until homogeneous to obtain an aqueous phase; S3. Add the oil phase mixture to the aqueous phase and stir until homogeneous to obtain a microemulsion; S4. Add fermented peppermint leaf extract, oat yeast and fucose-peptide microcapsules to the microemulsion, stir evenly, homogenize, degas under vacuum, sterilize and cool to obtain the synthetic peppermint oil composition.

10. The use of a synthetic peppermint oil composition as described in any one of claims 1-8 in daily chemical products, pharmaceutical preparations or food flavorings.

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