Efficient chamomile essential oil extraction method based on pH regulation and control

Abstract

The invention belongs to the technical field of plant essential oil extraction, and relates to an efficient chamomile essential oil extraction method based on pH regulation, which comprises the following steps: 1, raw material pretreatment; 2, pH regulation soaking: mixing the dried chamomile inflorescence with a buffer solution according to a material-liquid ratio of 1: (8-12), and soaking for 2-6 hours at room temperature; the pH of the soaking solution is 4.4-4.8, 6.3-6.5, 6.9-7.1, 8.4-8.8 and 9.2-9.4, an acidic system is adjusted by a citric acid-sodium citrate buffer solution, an alkaline system is adjusted by a sodium dihydrogen phosphate-sodium hydroxide buffer solution, and a neutral system is pure water; 3, extracting; 4, performing post-treatment; by accurately regulating and controlling the soaking pH, plant cell walls can be promoted to break to release essential oil components, oxidative degradation of active substances such as terpenoids can be reduced, the process is simple, the energy consumption is low, and the obtained essential oil is pure in fragrance, stable in quality and suitable for industrial production in the fields of spices, cosmetics and medicines.

Description

Technical Field

[0001] This invention belongs to the field of plant essential oil extraction technology, specifically relating to a highly efficient extraction method for chamomile essential oil based on pH control. Background Technology

[0002] Chamomile essential oil is rich in various active ingredients such as chamomile extract, flavonoids, and terpenes, possessing anti-inflammatory, soothing, and antioxidant properties. It is widely used in the fragrance, cosmetics, and pharmaceutical industries. Chamomile essential oil extraction refers to a series of processes for separating and obtaining the volatile aromatic components—essential oil—from the chamomile plant. Currently, there are several methods for extracting chamomile essential oil, mainly including: steam distillation, solvent extraction, supercritical fluid extraction, and microwave-assisted extraction. Among these, steam distillation is the traditional extraction method. It involves directly distilling dried chamomile using a simultaneous distillation apparatus. The resulting mixed steam is condensed to obtain an oil-water mixture. After separating the oil and water, the oil phase is dried with anhydrous magnesium sulfate, filtered, and then rotary evaporated to obtain the chamomile essential oil.

[0003] However, existing chamomile essential oil extraction processes have drawbacks, including long extraction times that can damage heat-sensitive aromatic substances in the essential oil, resulting in low extraction efficiency, typically around 0.3%. Therefore, current methods for extracting chamomile essential oil suffer from problems such as low extraction rates, long extraction times, and easy degradation of active ingredients.

[0004] Therefore, there is a need for a chamomile essential oil extraction method that has a high extraction rate, low cost, short processing time, and stable quality to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention addresses the problems of low yield, easy degradation of active ingredients during distillation, and high cost in existing chamomile essential oil extraction processes by providing a highly efficient chamomile essential oil extraction method based on pH control. By precisely controlling the pH of the soaking solution during pretreatment and combining it with steam distillation technology, the method improves the essential oil yield while protecting the integrity of the active ingredients. This method is simple, energy-efficient, and suitable for industrial production.

[0006] This invention provides the following technical solution: a method for efficient extraction of chamomile essential oil based on pH control, comprising the following steps: Step 1, Raw material pretreatment: Select dried chamomile inflorescences that are full in color and free from insect damage; Step 2, pH-adjusted soaking: Mix the dried chamomile inflorescences with buffer solution at a material-to-liquid ratio of 1:8-12 and soak at room temperature for 2-6 hours; the pH of the soaking solution includes: 4.4-4.8, 6.3-6.5, 6.9-7.1, 8.4-8.8, and 9.2-9.4, wherein the acidic system is adjusted by citrate-sodium citrate buffer solution, the alkaline system is adjusted by sodium dihydrogen phosphate-sodium hydroxide buffer solution, and the neutral system is pure water; Step 3, Extraction: Extract the soaked material by steam distillation for 150-240 minutes; Step 4, Post-processing: Separate the oil-water mixture obtained from distillation, take the oil phase, dry it with anhydrous magnesium sulfate, and then rotary evaporate to obtain chamomile essential oil.

[0007] Preferably, in step 1, the moisture content of the dried chamomile inflorescence is ≤8%.

[0008] Preferably, in step 2, the dried chamomile inflorescence and the buffer solution are mixed at a ratio of 1:10.

[0009] Preferably, in step 2, the pH of the soaking solution is 4.5-4.7 or 8.5-8.7.

[0010] More preferably, the pH of the soaking solution is 4.59–4.61 or 8.59–8.61.

[0011] Preferably, in step 2, the soaking time is 5 hours.

[0012] Preferably, in step 3, the distillation time is 178–182 min.

[0013] Preferably, in step 4, the oil-water separation is performed by using a separating funnel for static separation, with a static time of 25-35 minutes.

[0014] The beneficial effects of this invention are: 1. Significantly improved yield: Through precise pH control, the release of chamomile essential oil is effectively promoted; experiments show that the essential oil yield reaches up to 1.53% under pH 4.6 conditions, which is more than four times higher than the traditional pure water soaking process and better than most existing conventional processes.

[0015] 2. High quality stability: The use of a buffer system to achieve stable pH control avoids the damage of active ingredients such as chamomile and terpenes to excessively acidic or alkaline environments. The resulting essential oil has a pure aroma and no off-odor. The retention rate of active ingredients is 15% to 20% higher than that of traditional processes.

[0016] 3. Good process economy: Based on steam distillation, only a pH control soaking step is added. No complicated equipment modification is required, which can shorten the distillation time by more than 30% and significantly reduce energy consumption; the buffer solution can be prepared by conventional chemical reagents, which is inexpensive and easy to obtain.

[0017] 4. Wide applicability: The process is simple to operate and the parameters are easy to control, which can be adapted to the production needs of different scales. The obtained essential oils can be directly applied to the fields of fragrance, cosmetics and medicine, and have good industrial promotion value. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of uniformly sized dried chamomile inflorescences selected by the pH-controlled high-efficiency extraction method for chamomile essential oil according to the present invention. Figure 2 This is a schematic diagram of the extraction and post-processing of chamomile essential oil according to the present invention; Figure 3 Line graph showing the effect of different embodiments of the present invention on the yield of chamomile essential oil; Figure 4 This is a schematic diagram of the method steps of the present invention. Detailed Implementation

[0019] The related technologies of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figures 1-4 As shown, the pH-controlled high-efficiency extraction method for chamomile essential oil in this embodiment includes the following steps: Step 1: Raw material pretreatment: Select dried chamomile inflorescences as raw materials. After screening to remove impurities, obtain dried chamomile inflorescences of uniform size. The moisture content of the dried chamomile inflorescences should be ≤8% to reduce errors in the subsequent extraction process.

[0021] Step 2, pH-controlled soaking: Mix dried chamomile inflorescences with buffer solution at a material-to-liquid ratio of 1:10 and soak at room temperature for 5 hours; the pH of the buffer solution is 4.6, 6.4, 7.0, 8.6, and 9.3, respectively. The acidic system is adjusted by citric acid-sodium citrate buffer solution, the alkaline system is adjusted by sodium dihydrogen phosphate-sodium hydroxide buffer solution, and the neutral system is pure water. By precisely controlling the pH, the plant cell wall is broken down, while the degradation of active ingredients during distillation is reduced.

[0022] Step 3, Extraction: Transfer the soaked liquid to a steam distillation apparatus, turn on the distillation system, and distill for 180 minutes.

[0023] Step 4, Post-processing: Pour the oil-water mixture obtained from distillation into a separatory funnel, let it stand for 30 minutes to allow natural separation, and collect the upper oil phase; add anhydrous magnesium sulfate to the oil phase, stir, let it stand and dry for 1 hour, filter out the anhydrous magnesium sulfate, and rotary evaporate to obtain clear and transparent chamomile essential oil; store the obtained essential oil in a cool, dark environment at ≤20℃ in a sealed container to further improve aroma stability.

[0024] Furthermore, the material-to-liquid ratio in step 2 is 1:10. This ratio ensures that the raw materials are fully wetted while avoiding waste caused by excessive buffer solution.

[0025] Furthermore, the soaking described in step 2 at room temperature for 5 hours is the optimal condition for cell wall rupture and the lowest degradation rate of active ingredients.

[0026] Furthermore, the pH of the buffer solution in step 2 is 4.6, which is the optimal environment for the release of chamomile essential oil and can significantly improve the yield.

[0027] Furthermore, the distillation time in step 3 is 180 minutes, which can achieve full extraction of essential oils while avoiding excessive energy consumption and component damage.

[0028] Example Example 1 A method for efficient extraction of chamomile essential oil based on pH control includes the following steps: 1. Raw material pretreatment: Select dried chamomile inflorescences with a moisture content of less than 8%, screen and remove impurities to obtain chamomile inflorescences of uniform size; 2. pH-adjusted soaking: Mix dried chamomile inflorescences with a citric acid-sodium citrate buffer solution at a material-to-liquid ratio of 1:10 and soak at room temperature for 5 hours; 3. Extraction: Transfer the liquid to a distillation apparatus and distill for 180 minutes; 4. Post-processing: The oil-water mixture was allowed to stand for 30 minutes through a separatory funnel. The oil phase was collected, dried with anhydrous magnesium sulfate, and then rotary evaporated to obtain chamomile essential oil.

[0029] The chamomile essential oil yield obtained in this embodiment was 1.53%, and the aroma was pure and free of any off-flavors.

[0030] Example 2 The difference from Example 1 is that the soaking pH was adjusted to 6.4. The remaining steps are the same as in Example 1.

[0031] A method for efficient extraction of chamomile essential oil based on pH control includes the following steps: 1. Raw material pretreatment: Select dried chamomile inflorescences with a moisture content of less than 8%, screen and remove impurities to obtain chamomile inflorescences of uniform size; 2. pH-adjusted soaking: Mix dried chamomile inflorescences with a citric acid-sodium citrate buffer solution at a material-to-liquid ratio of 1:10 and soak at room temperature for 5 hours; 3. Extraction: Transfer the liquid to a distillation apparatus and distill for 180 minutes; 4. Post-processing: The oil-water mixture was allowed to stand for 30 minutes through a separatory funnel. The oil phase was collected, dried with anhydrous magnesium sulfate, and then rotary evaporated to obtain chamomile essential oil.

[0032] The chamomile essential oil yield obtained in this embodiment was 0.37%, and the aroma was pure and free of any off-flavors.

[0033] Example 3 The difference from Example 1 is that the soaking pH was adjusted to 8.6. The remaining steps are the same as in Example 1.

[0034] A method for efficient extraction of chamomile essential oil based on pH control includes the following steps: 1. Raw material pretreatment: Select dried chamomile inflorescences with a moisture content of less than 8%, screen and remove impurities to obtain chamomile inflorescences of uniform size; 2. pH-adjusted soaking: Mix dried chamomile inflorescences with a sodium dihydrogen phosphate-sodium hydroxide buffer solution at a material-to-liquid ratio of 1:10 and soak at room temperature for 5 hours; 3. Extraction: Transfer the liquid to a distillation apparatus and distill for 180 minutes; 4. Post-processing: The oil-water mixture was allowed to stand for 30 minutes through a separatory funnel. The oil phase was collected, dried with anhydrous magnesium sulfate, and then rotary evaporated to obtain chamomile essential oil.

[0035] The chamomile essential oil yield obtained in this embodiment was 1.37%, and the aroma was pure and free of any off-flavors.

[0036] Example 4 The difference from Example 1 is that the soaking pH was adjusted to 9.3, and the rest of the steps are the same as in Example 1.

[0037] A method for efficient extraction of chamomile essential oil based on pH control includes the following steps: 1. Raw material pretreatment: Select dried chamomile inflorescences with a moisture content of less than 8%, screen and remove impurities to obtain chamomile inflorescences of uniform size; 2. pH-adjusted soaking: Mix dried chamomile inflorescences with a sodium dihydrogen phosphate-sodium hydroxide buffer solution at a material-to-liquid ratio of 1:10 and soak at room temperature for 5 hours; 3. Extraction: Transfer the liquid to a distillation apparatus and distill for 180 minutes; 4. Post-processing: The oil-water mixture was allowed to stand for 30 minutes through a separatory funnel. The oil phase was collected, dried with anhydrous magnesium sulfate, and then rotary evaporated to obtain chamomile essential oil.

[0038] The yield of chamomile essential oil obtained in this embodiment was 0.43%, and the aroma was pure and free of any off-flavors.

[0039] Example 5 The difference from Example 1 is that the feed-to-liquid ratio was adjusted to 1:8 and the distillation time was adjusted to 150 min. The remaining steps are the same as in Example 1.

[0040] A method for efficient extraction of chamomile essential oil based on pH control includes the following steps: 1. Raw material pretreatment: Select dried chamomile inflorescences with a moisture content of less than 8%, screen and remove impurities to obtain chamomile inflorescences of uniform size; 2. pH-adjusted soaking: Mix dried chamomile inflorescences with a citric acid-sodium citrate buffer solution at a material-to-liquid ratio of 1:8, and soak at room temperature for 5 hours; 3. Extraction: Transfer the liquid to a distillation apparatus and distill for 150 minutes; 4. Post-processing: The oil-water mixture was allowed to stand for 30 minutes through a separatory funnel. The oil phase was collected, dried with anhydrous magnesium sulfate, and then rotary evaporated to obtain chamomile essential oil.

[0041] The chamomile essential oil yield obtained in this embodiment was 0.38%, and the aroma was pure and free of any off-flavors.

[0042] Example 6 The difference from Example 1 is that the feed-to-liquid ratio was adjusted to 1:12 and the distillation time was adjusted to 150 min. The remaining steps are the same as in Example 1.

[0043] A method for efficient extraction of chamomile essential oil based on pH control includes the following steps: 1. Raw material pretreatment: Select dried chamomile inflorescences with a moisture content of less than 8%, screen and remove impurities to obtain chamomile inflorescences of uniform size; 2. pH-adjusted soaking: Mix dried chamomile inflorescences with a citric acid-sodium citrate buffer solution at a material-to-liquid ratio of 1:12 and soak at room temperature for 5 hours; 3. Extraction: Transfer the liquid to a distillation apparatus and distill for 150 minutes; 4. Post-processing: The oil-water mixture was allowed to stand for 30 minutes through a separatory funnel. The oil phase was collected, dried with anhydrous magnesium sulfate, and then rotary evaporated to obtain chamomile essential oil.

[0044] The chamomile essential oil yield obtained in this embodiment was 0.25%, and the aroma was pure and free of any off-flavors.

[0045] Example 7 The difference from Example 1 is that the distillation time was adjusted to 150 min. The remaining steps are the same as in Example 1.

[0046] A method for efficient extraction of chamomile essential oil based on pH control includes the following steps: 1. Raw material pretreatment: Select dried chamomile inflorescences with a moisture content of less than 8%, screen and remove impurities to obtain chamomile inflorescences of uniform size; 2. pH-adjusted soaking: Mix dried chamomile inflorescences with a citric acid-sodium citrate buffer solution at a material-to-liquid ratio of 1:10 and soak at room temperature for 5 hours; 3. Extraction: Transfer the liquid to a distillation apparatus and distill for 150 minutes; 4. Post-processing: The oil-water mixture was allowed to stand for 30 minutes through a separatory funnel. The oil phase was collected, dried with anhydrous magnesium sulfate, and then rotary evaporated to obtain chamomile essential oil.

[0047] The yield of chamomile essential oil obtained in this embodiment was 0.47%, and the aroma was pure and free of any off-flavors.

[0048] Example 8 The difference from Example 1 is that the soaking time was adjusted to 2 hours. The remaining steps are the same as in Example 1.

[0049] A method for efficient extraction of chamomile essential oil based on pH control includes the following steps: 1. Raw material pretreatment: Select dried chamomile inflorescences with a moisture content of less than 8%, screen and remove impurities to obtain chamomile inflorescences of uniform size; 2. pH-adjusted soaking: Mix dried chamomile inflorescences with a citric acid-sodium citrate buffer solution at a material-to-liquid ratio of 1:10 and soak at room temperature for 2 hours; 3. Extraction: Transfer the liquid to a distillation apparatus and distill for 180 minutes; 4. Post-processing: The oil-water mixture was allowed to stand for 30 minutes through a separatory funnel. The oil phase was collected, dried with anhydrous magnesium sulfate, and then rotary evaporated to obtain chamomile essential oil.

[0050] The yield of chamomile essential oil obtained in this embodiment was 0.47%, and the aroma was pure and free of any off-flavors.

[0051] Example 9 The difference from Example 1 is that the dried chamomile inflorescences were not soaked. The remaining steps are the same as in Example 1.

[0052] A method for efficient extraction of chamomile essential oil based on pH control includes the following steps: 1. Raw material pretreatment: Select dried chamomile inflorescences with a moisture content of less than 8%, screen and remove impurities to obtain chamomile inflorescences of uniform size; 2. pH-controlled soaking: Mix dried chamomile inflorescences with a citric acid-sodium citrate buffer solution at a material-to-liquid ratio of 1:10, without soaking; 3. Extraction: Transfer the liquid to a distillation apparatus and distill for 180 minutes; 4. Post-processing: The oil-water mixture was allowed to stand for 30 minutes through a separatory funnel. The oil phase was collected, dried with anhydrous magnesium sulfate, and then rotary evaporated to obtain chamomile essential oil.

[0053] The chamomile essential oil yield obtained in this embodiment was 0.34%, and the aroma was pure and free of any off-flavors.

[0054] Example 10 The difference from Example 1 is that the distillation time was adjusted to 240 min. The remaining steps are the same as in Example 1.

[0055] A method for efficient extraction of chamomile essential oil based on pH control includes the following steps: 1. Raw material pretreatment: Select dried chamomile inflorescences with a moisture content of less than 8%, screen and remove impurities to obtain chamomile inflorescences of uniform size; 2. pH-adjusted soaking: Mix dried chamomile inflorescences with a citric acid-sodium citrate buffer solution at a material-to-liquid ratio of 1:10 and soak at room temperature for 5 hours; 3. Extraction: Transfer the liquid to a distillation apparatus and distill for 240 minutes; 4. Post-processing: The oil-water mixture was allowed to stand for 30 minutes through a separatory funnel. The oil phase was collected and dehydrated with anhydrous magnesium sulfate. After rotary evaporation, chamomile essential oil was obtained.

[0056] The yield of chamomile essential oil obtained in this embodiment was 0.32%, and the aroma was pure and free of any off-flavors.

[0057] Comparative experiment Using traditional pure water soaking (pH=7.0) as a control group, the process of Example 1 of this invention was compared with that of the present invention. The results are shown in the table below:

[0058] As shown in Table 1 above, the method of this invention is significantly superior to traditional processes in terms of essential oil yield, retention of active ingredients, and extraction efficiency. This invention achieves efficient and green preparation of chamomile essential oil by precisely controlling pH and optimizing extraction parameters. This method not only significantly improves essential oil yield and quality but also effectively controls production costs by simplifying the process, reducing equipment modification requirements and energy consumption. Experimental data fully verify its technical advantages and the feasibility of industrial application, providing an innovative solution for the field of natural plant essential oil extraction and promoting the technological upgrading and sustainable development of related industries.

[0059] In summary, this invention, through precise control of the soaking pH, can promote the rupture of plant cell walls to release essential oil components, while reducing the oxidative degradation of active substances such as terpenes. Moreover, the process is simple, energy consumption is low, and the resulting essential oil has a pure aroma and stable quality, making it suitable for industrial production in the fields of fragrance, cosmetics, and pharmaceuticals.

[0060] It should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for efficient extraction of chamomile essential oil based on pH control, characterized in that, Includes the following steps: Step 1, Raw material pretreatment: Select dried chamomile inflorescences that are full in color and free from insect damage; Step 2, pH-adjusted soaking: Mix the dried chamomile inflorescences with buffer solution at a material-to-liquid ratio of 1:8-12 and soak at room temperature for 2-6 hours; the pH of the soaking solution includes: 4.4-4.8, 6.3-6.5, 6.9-7.1, 8.4-8.8, and 9.2-9.4, wherein the acidic system is adjusted by citrate-sodium citrate buffer solution, the alkaline system is adjusted by sodium dihydrogen phosphate-sodium hydroxide buffer solution, and the neutral system is pure water; Step 3, Extraction: Extract the soaked material by steam distillation for 150-240 minutes; Step 4, Post-processing: Separate the oil-water mixture obtained from distillation, take the oil phase, dry it with anhydrous magnesium sulfate, and then rotary evaporate to obtain chamomile essential oil.

2. The method for efficient extraction of chamomile essential oil based on pH control according to claim 1, characterized in that, In step 1, the moisture content of the dried chamomile inflorescence is ≤8%.

3. The method for efficient extraction of chamomile essential oil based on pH control according to claim 1, characterized in that, In step 2, the dried chamomile inflorescences and the buffer solution are mixed at a ratio of 1:

10.

4. The method for efficient extraction of chamomile essential oil based on pH control according to claim 1, characterized in that, In step 2, the pH of the soaking solution is 4.5-4.7 or 8.5-8.

7.

5. The method for efficient extraction of chamomile essential oil based on pH control according to claim 4, characterized in that, The pH of the soaking solution is 4.59–4.61 or 8.59–8.

61.

6. The method for efficient extraction of chamomile essential oil based on pH control according to claim 1, characterized in that, In step 2, the soaking time is 5 hours.

7. The method for efficient extraction of chamomile essential oil based on pH control according to claim 1, characterized in that, In step 3, the distillation time is 178–182 min.

8. The method for efficient extraction of chamomile essential oil based on pH control according to claim 1, characterized in that, In step 4, the oil-water separation is performed by using a separating funnel for static separation, with a static time of 25-35 minutes.

9. The method for efficient extraction of chamomile essential oil based on pH control according to any one of claims 1-8: characterized in that, The yield of chamomile essential oil was 0.30% to 1.53%.

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