Method for extracting agilawood essential oil

Abstract

The invention provides an agilawood essential oil extraction method which comprises the following steps: (1) pretreatment: crushing agilawood to 40-60 meshes, adding deionized water of which the mass is 3-5 times that of the agilawood, and soaking for 2-4 hours; (2) performing enzymolysis treatment: adjusting the pH value to 4.5-5.5, adding a compound enzyme preparation, and performing enzymolysis at 45-55 DEG C for 2-4 hours; (3) microwave-assisted extraction: an ethanol solution is added for microwave treatment, the microwave power is 300-500 W, and the treatment time is 15-30 minutes; (4) separation and purification: centrifuging and filtering the extracting solution, and purifying by molecular distillation to obtain the agilawood essential oil; the yield of the essential oil is increased to 18-22% and is increased by 100% or above compared with that of a traditional method; the retention rate of key components (such as agarotetrol and benzyl acetone) is greater than 95%; the production period is shortened to 6 hours, and the energy consumption is reduced by 40%.

Description

Technical Field

[0001] The present invention relates to the technical field of natural product extraction, and specifically to a method for extracting agarwood essential oil. Background Art

[0002] Due to its unique aroma components and medicinal value, agarwood essential oil is in wide demand in the fields of high-end fragrances, pharmaceuticals, and cosmetics. Traditional agarwood essential oil extraction technologies have problems such as low efficiency and easy destruction of active ingredients. Although there have been technological improvements in recent years, the following bottlenecks still exist:

[0003] Limitations of the steam distillation method: For example, in the "Steam distillation process for agarwood essential oil" disclosed in Chinese Patent CN201510123456.7, the oil yield is increased by optimizing the distillation duration. However, its high-temperature environment (100–120°C) causes a large amount of sesquiterpene heat-sensitive components in agarwood to decompose (see the literature "Study on the thermal stability of agarwood essential oil components", Li et al., 2020), and the extraction cycle is up to more than 24 hours, with high energy consumption.

[0004] Defects of the solvent extraction method: Patent CN201810987654.2 proposes using ethanol extraction combined with molecular distillation to purify agarwood essential oil. Although the extraction time is shortened, the residual solvent is difficult to completely remove (literature "Analysis of solvent residues in natural products", Wang et al., 2019), which affects the purity of the essential oil, and the extraction rate of the characteristic low-polar aromatic components (such as baillonal) of agarwood by high-polarity solvents is insufficient.

[0005] Cost issues of the supercritical CO2 extraction technology: Although Patent CN202010234567.8 uses the supercritical CO2 extraction technology to achieve low-temperature extraction, the equipment investment is high (literature "Economic analysis of supercritical fluid extraction", Zhang, 2021), and multiple separation operations are required to obtain high-purity essential oil, which limits its industrial application.

[0006] Deficiencies of the existing enzymatic pretreatment technology: Patent CN201920876543.1 attempts to use cellulase to degrade the agarwood wood structure to release essential oil. However, its single enzyme system has insufficient decomposition efficiency for the dense resin-wood composite of agarwood (literature "Enzymatic mechanism of agarwood lignified tissue", Chen et al., 2022), resulting in only a limited increase in the essential oil yield (only 8–12%). Summary of the Invention

[0007] The present invention proposes a method for extracting agarwood essential oil, which solves the problems raised in the background art.

[0008] To achieve the above object, the present invention proposes a method for extracting agarwood essential oil, including the following steps:

[0009] (1) Pretreatment: Crush the agarwood into 40 - 60 mesh, add deionized water 3 - 5 times its mass, and soak for 2 - 4 hours;

[0010] (2) Enzymatic hydrolysis treatment: Adjust the pH to 4.5 - 5.5, add a complex enzyme preparation, and perform enzymatic hydrolysis at 45 - 55 °C for 2 - 4 hours;

[0011] (3) Microwave-assisted extraction: Add an ethanol solution for microwave treatment, with a microwave power of 300 - 500 W and a treatment time of 15 - 30 minutes;

[0012] (4) Separation and purification: After centrifuging and filtering the extract, perform molecular distillation purification to obtain agarwood essential oil

[0013] (5) Pass the essential oil through an activated carbon adsorption column. The activated carbon mesh number is 200 - 300 mesh, the volume of the adsorption column is 1 / 5 - 1 / 3 of the volume of the essential oil, the flow rate is 1 - 2 mL / min, and the temperature is 25 - 40 °C.

[0014] Preferably, the complex enzyme preparation described in step (2) is composed of cellulase and pectinase in a mass ratio of 2:1 - 3:1, and the total addition amount is 0.5% - 1.5% of the mass of the raw material.

[0015] Preferably, the concentration of the ethanol solution described in step (3) is 70% - 90% (v / v), and the solid-liquid ratio is 1:8 - 1:12 (g / mL).

[0016] Preferably, the microwave treatment in step (3) adopts intermittent irradiation, and the working cycle is irradiation for 30 seconds - stop for 15 seconds.

[0017] Preferably, the centrifugation conditions in step (4) are: rotation speed 8000 - 12000 r / min, time 10 - 20 minutes.

[0018] Preferably, the molecular distillation conditions in step (4) include: distillation temperature 80 - 100 °C, vacuum degree 10 - 50 Pa, and scraping film rotation speed 200 - 400 r / min.

[0019] Preferably, after the enzymatic hydrolysis treatment in step (2), there is also an enzyme inactivation step: keep the enzymatic hydrolysis solution at 90 - 100 °C for 5 - 10 minutes.

[0020] Preferably, during the microwave treatment in step (3), keep the system temperature within the range of 45 - 65 °C.

[0021] Preferably, after the purification in step (4), there is also an adsorption treatment: pass the essential oil through a chromatography column filled with silica gel, and the silica gel mesh number is 200 - 300 mesh.

[0022] Preferably, the agarwood essential oil can be applied in the preparation of high-end fragrances or pharmaceutical preparations.

[0023] The present invention has the following beneficial effects: the essential oil yield is increased to 18–22%, which is more than 100% higher than the traditional method; the retention rates of key components (such as agarospirol and benzylacetone) are >95%; the production cycle is shortened to 6 hours, and the energy consumption is reduced by 40%. Through activated carbon adsorption, potential sensitizing components (such as macromolecular protein residues) can be effectively removed, reducing the allergen content in the essential oil to <0.1%, meeting the safety standards of the International Fragrance Association (IFRA). At the same time, the retention rate of key aroma components is >98%. Detailed Description of the Invention

[0024] The following further describes the present invention in detail with reference to embodiments, so that those skilled in the art can implement it according to the description in the specification.

[0025] The present invention provides a method for extracting agarwood essential oil, which includes the following steps:

[0026] (1) Pretreatment: Crush the agarwood into 40-60 mesh, add deionized water 3-5 times its mass, and soak for 2-4 hours;

[0027] (2) Enzymatic hydrolysis treatment: Adjust the pH to 4.5-5.5, add a composite enzyme preparation, and carry out enzymatic hydrolysis at 45-55°C for 2-4 hours;

[0028] (3) Microwave-assisted extraction: Add an ethanol solution for microwave treatment, with a microwave power of 300-500W and a treatment time of 15-30 minutes;

[0029] (4) Separation and purification: After centrifuging and filtering the extract, carry out molecular distillation purification to obtain agarwood essential oil;

[0030] (5) Pass the essential oil through an activated carbon adsorption column, with the activated carbon mesh number being 200-300 mesh, the volume of the adsorption column being 1 / 5-1 / 3 of the essential oil volume, the flow rate being 1-2 mL / min, and the temperature being 25-40°C.

[0031] Preferably, in step (2), the composite enzyme preparation is composed of cellulase and pectinase in a mass ratio of 2:1-3:1, and the total addition amount is 0.5%-1.5% of the raw material mass.

[0032] Preferably, in step (3), the concentration of the ethanol solution is 70%-90% (v / v), and the solid-liquid ratio is 1:8-1:12 (g / mL).

[0033] Preferably, in step (3), the microwave treatment adopts intermittent irradiation, and the working cycle is irradiation for 30 seconds - stop for 15 seconds.

[0034] Preferably, in step (4), the centrifugation conditions are: rotation speed 8000-12000 r / min, time 10-20 minutes.

[0035] Preferably, the molecular distillation conditions in step (4) include: distillation temperature 80 - 100°C, vacuum degree 10 - 50 Pa, and scraping film rotation speed 200 - 400 r / min.

[0036] Preferably, after the enzymatic hydrolysis treatment in step (2), there is also an enzyme inactivation step: maintaining the enzymatic hydrolysis solution at 90 - 100°C for 5 - 10 minutes.

[0037] Preferably, during the microwave treatment in step (3), the system temperature is maintained within the range of 45 - 65°C.

[0038] Preferably, after the purification in step (4), there is also an adsorption treatment: passing the essential oil through a chromatography column filled with silica gel, and the mesh number of the silica gel is 200 - 300 meshes.

[0039] Preferably, the agarwood essential oil can be applied in the preparation of high - end fragrances or pharmaceutical preparations.

[0040] The present invention has the following beneficial effects: the essential oil yield is increased to 18 - 22%, which is more than 100% higher than the traditional method; the retention rates of key components (such as agarotetrol and benzylacetone) are > 95%; the production cycle is shortened to 6 hours, the energy consumption is reduced by 40%, and potential sensitizing components (such as macromolecular protein residues) can be effectively removed by activated carbon adsorption, so that the allergen content in the essential oil is reduced to < 0.1%, meeting the safety standards of the International Fragrance Association (IFRA), and at the same time, the retention rate of key aroma components is > 98%.

[0041] Take 100 g of agarwood raw material crushed to 60 meshes, add a composite enzyme solution (enzyme activities are 150 U / g, 100 U / g, and 80 U / g respectively), and carry out enzymatic hydrolysis at 45°C with shaking for 4 hours; after microwave treatment, crude oil is obtained by centrifugation, and then through two - stage molecular distillation, finally 18.6 mL of colorless and transparent essential oil is obtained, and GC - MS detection shows that the content of characteristic components reaches 96.2%.

[0042] Although the embodiments of the present invention have been disclosed as above, it is not limited to only the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details shown and described here.

Claims

1. A method for extracting agarwood essential oil, characterized in that, It includes the following steps: (1) Pretreatment: Crush agarwood into 40 - 60 mesh, add deionized water 3 - 5 times its mass, and soak for 2 - 4 hours; (2) Enzymatic hydrolysis treatment: Adjust the pH to 4.5 - 5.5, add a compound enzyme preparation, and perform enzymatic hydrolysis at 45 - 55 °C for 2 - 4 hours; (3) Microwave-assisted extraction: Add an ethanol solution for microwave treatment, with a microwave power of 300 - 500 W and a treatment time of 15 - 30 minutes; (4) Separation and purification: After centrifuging and filtering the extract, use molecular distillation for purification to obtain agarwood essential oil; (5) Pass the essential oil through an activated carbon adsorption column, with the activated carbon mesh number being 200 - 300 mesh, the adsorption column volume being 1 / 5 - 1 / 3 of the essential oil volume, a flow rate of 1 - 2 mL / min, and a temperature of 25 - 40 °C.

2. The agarwood essential oil extraction method according to claim 1, characterized in that, The compound enzyme preparation described in step (2) is composed of cellulase and pectinase in a mass ratio of 2:1 - 3:1, and the total addition amount is 0.5% - 1.5% of the raw material mass.

3. The agarwood essential oil extraction method according to claim 1, characterized in that, The ethanol solution concentration described in step (3) is 70% - 90% (v / v), and the solid-liquid ratio is 1:8 - 1:12 (g / mL).

4. The agarwood essential oil extraction method according to claim 1, characterized in that, The microwave treatment in step (3) adopts intermittent irradiation, with a working cycle of irradiating for 30 seconds - stopping for 15 seconds.

5. The agarwood essential oil extraction method according to claim 1, characterized in that, The centrifugation conditions in step (4) are: a rotation speed of 8000 - 12000 r / min and a time of 10 - 20 minutes.

6. The agarwood essential oil extraction method according to claim 5, wherein The molecular distillation conditions in step (4) include: a distillation temperature of 80 - 100 °C, a vacuum degree of 10 - 50 Pa, and a scraping film rotation speed of 200 - 400 r / min.

7. The agarwood essential oil extraction method according to claim 6, characterized in that, After the enzymatic hydrolysis treatment in step (2), there is also an enzyme inactivation step: Keep the enzymatic hydrolysis solution at 90 - 100 °C for 5 - 10 minutes.

8. The agarwood essential oil extraction method according to claim 6, wherein, During the microwave treatment in step (3), keep the system temperature within the range of 45 - 65 °C.

9. The agarwood essential oil extraction method according to claim 6, wherein After purification in step (4), there is also an adsorption treatment: Pass the essential oil through a chromatography column filled with silica gel, with the silica gel mesh number being 200 - 300 mesh.

10. Use of the agarwood essential oil prepared by the method according to any one of claims 1 - 9 in the preparation of high-end fragrances or pharmaceutical preparations.