A refined compound mint essential oil and a preparation method thereof

Abstract

The application discloses a refined compound peppermint essential oil and a preparation method thereof. The application realizes targeted removal of miscellaneous gas of the peppermint oil and optimization of the sense by using the compound-molecular distillation combined technology, the operation temperature of the preparation process is low, and decomposition of heat-sensitive substances is avoided; the obtained peppermint essential oil is free of harmful solvent residues, rich in effective components, has a fragrance, is stable in quality, and comprehensively has the effective components of three kinds of peppermint oils, and removes the miscellaneous gas components of the peppermint oil, so that the fragrance purity of the peppermint essential oil is improved, and the fragrance levels are more abundant. The peppermint essential oil of the application is suitable for product development such as food, and has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of natural plant essential oil purification and compounding technology, specifically relating to a refined compound peppermint essential oil and its preparation method. Background Technology

[0002] Traditional single-ingredient peppermint essential oils suffer from drawbacks such as a heavy, unbalanced aroma and a limited range of flavor profiles. While Asian peppermint (Mentha haplocalyx) provides a strong cooling sensation due to its high menthol content, it can be irritating. Peppermint (Mentha ×piperita), despite containing sweet components like menthol, lacks the characteristic cooling sensation of peppermint. Spearmint (Mentha spicata), while possessing a mild grassy aroma, also exhibits earthy and other off-flavors. Blending techniques can enhance the complexity of the peppermint aroma, but undesirable flavors also increase, with oily, woody, and musty notes remaining. Purifying single-ingredient essential oils before blending can mitigate these oily and musty notes to some extent, but using purified oils results in an overly clean and monotonous aroma, and the process is cumbersome, inefficient, and not cost-effective. Summary of the Invention

[0003] To overcome the aforementioned technical bottlenecks, this invention provides a refined compound peppermint essential oil and its preparation method, which is a method for selectively removing various off-odor substances (woody smell, earthy smell, rancid smell, etc.) from peppermint oil and enriching the aroma active ingredients through molecular distillation.

[0004] This invention employs a pre-blending followed by molecular distillation technique to maximize the aroma advantages of various peppermint essential oils, minimize the amount of substances to be separated, and optimize economic efficiency. During the blending process, the aroma components first achieve a good balance, with some undesirable odor substances masking and harmonizing with each other. The remaining small amount of woody and oily odors that cannot be masked are then removed using molecular distillation. This invention targets the synergistic application of three peppermint oils: Asian peppermint, peppermint, and spearmint. Through high-vacuum gradient control and multi-stage condensation temperature matching, it achieves precise separation of off-odor substances from the target aroma components in the peppermint oil, simultaneously removing impurities and enriching menthol.

[0005] The first objective of this invention is to provide a method for preparing refined compound peppermint essential oil, comprising the following steps: S1. Mix Asian peppermint oil, peppermint oil, and spearmint oil to obtain a compound peppermint oil; S2. The compound peppermint oil was subjected to molecular distillation at a temperature of 65°C; the light phase was collected at -5°C and the heavy phase was collected at 40°C. S3. Perform molecular distillation on the heavy phase obtained in step S2 at a distillation temperature of 75℃; collect the light phase at -5℃ and the heavy phase at 40℃. S4. Perform molecular distillation on the heavy phase obtained in step S3 at a distillation temperature of 85℃; collect the light phase at -5℃ and the heavy phase at 40℃. S5. Mix the light phase obtained in step S3 and the light phase obtained in step S4 to obtain refined compound peppermint essential oil.

[0006] Preferably, step S1 is: mixing the three peppermint oils in a volume ratio of Asian peppermint oil: peppermint oil: spearmint oil = 1:0.8-1.5:1.5-2.06 to obtain a compound peppermint oil.

[0007] Preferably, step S1 is: mixing the three peppermint oils in a volume ratio of Asian peppermint oil: peppermint oil: spearmint oil = 1:0.8:1.5 to obtain a compound peppermint oil.

[0008] Preferably, the vacuum degree of molecular distillation in steps S2-S4 is 5-20 Pa and the scraping speed is 300 r / min.

[0009] Preferably, the vacuum degree of molecular distillation in step S2 is 15 Pa, the vacuum degree of molecular distillation in step S3 is 10 Pa, and the vacuum degree of molecular distillation in step S4 is 5 Pa.

[0010] Preferably, the vacuum degree of molecular distillation in step S2 is 20 Pa, the vacuum degree of molecular distillation in step S3 is 15 Pa, and the vacuum degree of molecular distillation in step S4 is 10 Pa.

[0011] Preferably, the feed rate for molecular distillation in steps S2-S4 is 15 mL / min.

[0012] A second objective of this invention is to provide a refined compound peppermint essential oil prepared according to the method described above.

[0013] A third objective of this invention is to provide the application of the refined compound peppermint essential oil in food, beverages, and daily chemical products.

[0014] The "compound-molecular distillation combined technology" of this invention achieves a breakthrough improvement through the following technical path: 1. Targeted removal of impurities: Molecular distillation technology is used to selectively separate at low temperatures of 65℃-85℃. While retaining core functional components such as menthol and menthone, it effectively removes oily, earthy, and woody odors, significantly improving the purity of the aroma, and simultaneously concentrating key active substances such as peppermint furan and L-carvone.

[0015] 2. Sensory optimization: The blended system combines the cool base of Asian mint, the sweet embellishment of peppermint, and the grassy notes of spearmint to create a balanced three-dimensional aroma with improved odor masking.

[0016] The advantages of this invention's method are that the resulting peppermint essential oil has no harmful solvent residue, is rich in active ingredients, and has a pleasant aroma, making it suitable for food and other product development. Compared to traditional steam distillation, this invention operates at a lower temperature, avoiding the decomposition of heat-sensitive substances, resulting in stable product quality. It combines the active ingredients of three types of peppermint oil while removing impurities, thus improving the purity and complexity of the peppermint essential oil's aroma. Attached Figure Description

[0017] Figure 1 Crude oil analysis chromatogram for compound peppermint oil.

[0018] Figure 2 The light phase analysis spectrum is obtained from molecular distillation at 65°C.

[0019] Figure 3 The spectrum is a rephase analysis spectrum obtained by molecular distillation at 65℃.

[0020] Figure 4 The spectrum is for light phase analysis at 75℃ using molecular distillation.

[0021] Figure 5 The spectrum is a rephase analysis spectrum obtained by molecular distillation at 75°C.

[0022] Figure 6 The light phase analysis spectrum is obtained from molecular distillation at 85℃.

[0023] Figure 7 The spectrum is a rephase analysis spectrum obtained from molecular distillation at 85℃.

[0024] Figure 8 Radar graphs for sensory analysis of refined compound peppermint essential oil, compound peppermint oil and removed fractions. Detailed Implementation

[0025] The following embodiments are further illustrations of the present invention, but not limitations thereof.

[0026] The key information regarding the Asian peppermint oil, peppermint oil, and spearmint oil used in the following examples for compounding is as follows: Asian peppermint oil: CAS 68917-18-0 (Guangzhou Juhui Fragrance & Flavor Co., Ltd.), acid value (calculated as mg KOH / g): ≤1.0, dip value (ester content): 5.6 -18.4 (2.0% - 6.5%), acetylated ester value (equivalent to free alcohol content) ≥150 (45%), total alcohol content ≥50.0%, menthol >50%.

[0027] Peppermint oil: CAS 8006-90-4 (Guangzhou Juhui Flavor & Fragrance Co., Ltd.), ester content: ≥5.0%, total alcohol content: ≥50%, L-menthol: ≥40%, peppermint furan: 2.5%-6.5%.

[0028] Spearmint oil: CAS 6485-40-1 (Guangzhou Juhui Fragrance & Flavor Co., Ltd.), ester content: ≥5.0%, total alcohol content: ≥50%, L-menthol: ≥40%, mentholatum: 2.5%-6.5%.

[0029] The molecular distillation apparatus used in the following examples is a VDL70 (VTA VerfahrenstechnischeAnlagen Gmbh&Co.KG).

[0030] Example 1: Method for preparing refined compound peppermint essential oil using molecular distillation technology 1. Mix the three peppermint oils in a volume ratio of Asian peppermint oil: peppermint oil: spearmint oil = 1:0.8:1.5, and use 1 L of peppermint oil as the raw material.

[0031] 2. Add the raw material to the feed tank of the molecular distillation apparatus, add liquid nitrogen to the cold trap, feed rate is 15 mL / min, scraper speed is 300 r / min, vacuum degree is 15 Pa, distillation temperature is 65℃; collect the light phase at -5℃ and the heavy phase at 40℃.

[0032] 3. Add the heavy phase obtained in step 2 to the feed tank, add liquid nitrogen to the cold trap, feed rate is 15 mL / min, scraper speed is 300 r / min, vacuum degree is 10 Pa, distillation temperature is 75℃; collect the obtained light phase at -5℃ and collect the obtained heavy phase at 40℃.

[0033] 4. Add the heavy phase obtained in step 3 to the feed tank at a feed rate of 15 mL / min, a scraper speed of 300 r / min, a vacuum of 5 Pa, and a distillation temperature of 85℃; collect the light phase at -5℃ and the heavy phase at 40℃.

[0034] 5. Mix the light phase obtained in step 3 and the light phase obtained in step 4 (i.e., mix the components obtained after removing the light phase collected by distillation at 65℃ and the heavy phase collected by distillation at 85℃) to obtain a refined compound peppermint essential oil with obvious peppermint characteristics, pure aroma, and good aroma layering.

[0035] Example 2: Method for preparing refined compound peppermint essential oil using molecular distillation technology 1. Mix the three peppermint oils in a volume ratio of Asian peppermint oil: peppermint oil: spearmint oil = 1:1.5:2.06, and use 1 L of peppermint oil as the raw material.

[0036] 2. Add the raw material to the feed tank of the molecular distillation apparatus, add liquid nitrogen to the cold trap, feed rate is 15 mL / min, scraper speed is 300 r / min, vacuum degree is 15 Pa, distillation temperature is 65℃; collect the light phase at -5℃ and the heavy phase at 40℃.

[0037] 3. Add the heavy phase obtained in step 2 to the feed tank, add liquid nitrogen to the cold trap, feed rate is 15 mL / min, scraper speed is 300 r / min, vacuum degree is 10 Pa, distillation temperature is 75℃; collect the obtained light phase at -5℃ and collect the obtained heavy phase at 40℃.

[0038] 4. Add the heavy phase obtained in step 3 to the feed tank at a feed rate of 15 mL / min, a scraper speed of 300 r / min, a vacuum of 5 Pa, and a distillation temperature of 85℃; collect the light phase at -5℃ and the heavy phase at 40℃.

[0039] 5. Mix the light phase obtained in step 3 and the light phase obtained in step 4 (i.e., mix the components obtained after removing the light phase collected by distillation at 65℃ and the heavy phase collected by distillation at 85℃) to obtain a refined compound peppermint essential oil with obvious peppermint characteristics, pure aroma, and good aroma layering.

[0040] Example 3: Method for preparing refined compound peppermint essential oil using molecular distillation technology 1. Mix the three peppermint oils in a volume ratio of Asian peppermint oil: peppermint oil: spearmint oil = 1:1.5:2.06, and use 1 L of peppermint oil as the raw material.

[0041] 2. Add the raw material to the feed tank of the molecular distillation apparatus, add liquid nitrogen to the cold trap, feed rate is 15 mL / min, scraper speed is 300 r / min, vacuum degree is 20 Pa, distillation temperature is 65℃; collect the light phase at -5℃ and the heavy phase at 40℃.

[0042] 3. Add the heavy phase obtained in step 2 to the feed tank, add liquid nitrogen to the cold trap, feed rate is 15 mL / min, scraper speed is 300 r / min, vacuum degree is 15 Pa, distillation temperature is 75℃; collect the obtained light phase at -5℃ and collect the obtained heavy phase at 40℃.

[0043] 4. Add the heavy phase obtained in step 3 to the feed tank, add liquid nitrogen to the cold trap, feed at a rate of 15 mL / min, scraper speed of 300 r / min, vacuum of 10 Pa, and distillation temperature of 85℃. Collect the light phase at -5℃ and the heavy phase at 40℃.

[0044] 5. Mix the light phase obtained in step 3 and the light phase obtained in step 4 (i.e., mix the components obtained after removing the light phase collected by distillation at 65℃ and the heavy phase collected by distillation at 85℃) to obtain a refined compound peppermint essential oil with obvious peppermint characteristics, pure aroma, and good aroma layering.

[0045] Example 4 The fractions obtained according to the method in Example 1 were diluted with n-hexane to prepare solutions, which were then injected into a gas chromatograph-mass spectrometer (GC-MS) to analyze the main components of each fraction. The spectra of the light phase at 65°C, the heavy phase at 65°C, the light phase at 75°C, the heavy phase at 75°C, the light phase at 85°C, and the heavy phase at 85°C are shown in the following figures. Figure 2-7 As shown, the data obtained from the analysis are shown in Table 1 (instrumentation method: CTC nonpolar column collection, addition of internal standard to obtain semi-quantitative data, and then calculation of relative content).

[0046] Analysis of the chromatogram of the compound peppermint oil according to step 1 of the method in Example 1 is as follows: Figure 1 As shown. The proportions of each component are as follows: 2,5-diethyltetrahydrofuran 0.01%, methylpinene 1.31%, 3-methylcyclohexanol 0.01%, camphene 0.01%, 3-methylcyclohexanone 0.01%, juniperene 0.55%, cis-p-menthol 0.04%, ethylpinene 1.99%, 3-octanone 0.03%, ethylmyrcene 0.21%, 3-octanol 0.20%, trans-p-menthol 0.03%, pseudolimonene 0.13%, butyl-3-carene 0.04%, 1,4-cineole 0.02%, methylterpinene 0.10%, p-menthene 0.02%, p-cymene 0.64%, D-limonene 1.98%, 1,8-cineole 2.47%, and propylterpinene 0.03%. Octyl alcohol 0.06%, trans-hydrated sapindus mucilage 0.02%, isoterpinene 0.01%, tetrahydrolinalool 0.01%, linalool 0.05%, isomenthol 0.03%, menthone 25.52%, menthofuran 15.86%, neomenthol 3.02%, isomenthone 5.23%, menthol 27.65%, isomenthol 0.23%, neoisomenthol 0.33%, methylterpineol 0.53%, menthyl acetate 0.01%, menthone 0.84%, carvone 0.06%, piperone 1.20%, decanol 0.03%, menthyl acetate 7.55%, mentholactone 0.02%, bourbonene 0.27%, caryophyllene 1.45%, methyl humulene 0.05%.

[0047] Table 1. Percentage of each component in the fraction obtained at different temperatures Example 5: Sensory Evaluation Experiment 1. Experimental Methods The refined compound peppermint essential oil was scored using an olfactory sensory evaluation method.

[0048] Sample preparation: Experimental group: The refined compound peppermint essential oil prepared in Example 1.

[0049] Control group 1: The compound peppermint oil prepared according to step 1 of the method in Example 1 (i.e., the volume ratio of each component is Asian peppermint oil: peppermint oil: spearmint oil = 1:0.8:1.5), that is, the compound peppermint oil without molecular distillation.

[0050] Control group 2: According to the method of Example 1, the removed fractions (i.e., the light phase collected by distillation at 65°C and the heavy phase collected by distillation at 85°C) were mixed as control group 2.

[0051] Blank group: purified water (used for evaluators' olfactory calibration).

[0052] Seven volunteers with no olfactory impairment and no history of smoking were recruited as evaluators. The evaluators were trained according to the evaluation dimensions and references shown in Table 2 to ensure a consistent understanding of each dimension.

[0053] Table 2 Evaluation Dimensions and References 2. Experimental Results The results are shown in Table 3 and Figure 8 As shown, the refined blended peppermint essential oil obtained through molecular distillation removes most of the components that negatively affect the sensory quality of peppermint oil, such as oily, earthy, and woody odors. The refined blended peppermint essential oil, after distillation and recombination, combines the characteristic aromas of three types of peppermint, resulting in better aroma purity and a significantly enhanced aroma complexity.

[0054] Table 3 Sensory evaluation scores

Claims

1. A method for preparing refined compound peppermint essential oil, characterized in that, Includes the following steps: S1. Mix Asian peppermint oil, peppermint oil, and spearmint oil in a volume ratio of 1:0.8:1.5 to obtain a compound peppermint oil; S2. The compound peppermint oil was subjected to molecular distillation at a temperature of 65°C; the light phase was collected at -5°C and the heavy phase was collected at 40°C. S3. Perform molecular distillation on the heavy phase obtained in step S2 at a distillation temperature of 75℃; collect the light phase at -5℃ and the heavy phase at 40℃. S4. Perform molecular distillation on the heavy phase obtained in step S3 at a distillation temperature of 85℃; collect the light phase at -5℃ and the heavy phase at 40℃. S5. Mix the light phase obtained in step S3 and the light phase obtained in step S4 to obtain refined compound peppermint essential oil.

2. The method according to claim 1, characterized in that, The vacuum degree of molecular distillation in steps S2-S4 is 5-20 Pa and the scraping speed is 300 r / min.

3. The method according to claim 2, characterized in that, The vacuum degree of molecular distillation in step S2 is 15 Pa, the vacuum degree of molecular distillation in step S3 is 10 Pa, and the vacuum degree of molecular distillation in step S4 is 5 Pa.

4. The method according to claim 2, characterized in that, The vacuum degree of molecular distillation in step S2 is 20 Pa, the vacuum degree of molecular distillation in step S3 is 15 Pa, and the vacuum degree of molecular distillation in step S4 is 10 Pa.

5. The method according to claim 1, characterized in that, The feed rate for molecular distillation in steps S2-S4 is 15 mL / min.

6. A refined compound peppermint essential oil prepared by the method according to any one of claims 1-5.

7. The application of the refined compound peppermint essential oil according to claim 6 in food and daily chemical products.

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