A Camellia Oil Rich in Oleanolic Acid and Its Preparation Method

Abstract

This invention provides a method for preparing camellia oil rich in oleanolic acid, comprising the following steps: (1) washing and draining fresh camellia fruit shells and / or tea leaves, then pulverizing them after vacuum freeze-drying to obtain freeze-dried powder A, and pulverizing dried camellia seed kernels to obtain seed kernel powder B. (2) mixing freeze-dried powder A and seed kernel powder B at a mass ratio of 1:(15-20). (3) adding a 25%-35% ethanol aqueous solution as an extraction solvent to the mixed raw materials, wherein the mass-volume ratio (g:mL) of the mixed raw materials to the extraction solvent is 1:(3-4); using a high-speed shearing device to vigorously stir and crush the mixed system for 3-10 minutes to achieve full cell wall disruption of the plant cells. (4) heating and reflux extraction; (5) three-phase separation and solvent reuse. This method has a high efficiency in transferring oleanolic acid from the raw materials to the oil phase.

Description

Technical Field

[0001] This invention belongs to the field of oil processing, specifically relating to a camellia oil rich in oleanolic acid and its preparation method. Background Technology

[0002] Camellia oil is an important woody edible oil in my country, rich in unsaturated fatty acids and possessing high nutritional value. The byproducts of camellia fruit—the shell and leaves—contain abundant triterpenoid active ingredients such as oleanolic acid, which have various physiological activities including antioxidant and anti-inflammatory effects.

[0003] Currently, the active ingredients of camellia oil mainly focus on polyphenols, flavonoids, squalene, sterols, and saponins. There are no reports in the existing technology of simultaneously enriching oleanolic acid from camellia fruit shell into camellia oil. This invention is the first to achieve the efficient transfer of oleanolic acid from camellia by-product to finished oil. However, the extraction of oleanolic acid usually uses high-concentration ethanol separately, which is independent of oil extraction, resulting in a long process flow, low resource utilization rate, and difficulty in efficiently and stably enriching oleanolic acid into camellia oil.

[0004] In addition, even when existing technologies attempt to combine oil extraction with active ingredient extraction, the following problems are often encountered: First, the extraction solvent (such as pure water or organic solvent) does not have a matching solubility for oil and polar active ingredients, making it difficult to achieve simultaneous and efficient extraction of the two; second, the partition coefficient of active ingredients in the oil phase is low, resulting in unsatisfactory enrichment; and third, the solvent consumption during the extraction process is large, recovery is difficult, and wastewater discharge is high, which does not meet the requirements of green manufacturing.

[0005] Therefore, in order to solve the problem of extracting oleanolic acid while ensuring its proper distribution in the oil and improving the oil extraction efficiency, it is of great practical significance to develop a preparation method that can simultaneously extract camellia oil and efficiently enrich oleanolic acid, while also possessing the characteristics of solvent recycling and environmental friendliness. Summary of the Invention

[0006] The purpose of this invention is to provide a simple, efficient, solvent-recyclable, and low-cost method for preparing camellia oil rich in oleanolic acid, which achieves the extraction of camellia oil and the efficient enrichment of oleanolic acid in one step, and solves the problem of solvent recycling, thereby producing high-value-added functional camellia oil.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] A method for preparing camellia oil rich in oleanolic acid, characterized by comprising the following steps:

[0009] (1) Raw material pretreatment: Wash and drain the fresh camellia fruit shells and / or camellia tea leaves, freeze-dry them under vacuum and then pulverize them to obtain freeze-dried powder A. Pulverize the dried camellia seed kernels to obtain seed kernel powder B.

[0010] (2) Raw material compounding: Mix freeze-dried powder A and kernel powder B at a mass ratio of 1: (15-20) until uniform.

[0011] (3) Solvent-assisted cell wall disruption extraction: Add a 25%-35% (v / v) ethanol aqueous solution to the mixed raw materials as the extraction solvent. The mass-volume ratio (g:mL) of the mixed raw materials to the extraction solvent is 1:(3-4). Use a high-speed shearing device (such as a cell wall disruptor) to vigorously stir and break down the mixed system for 3-10 minutes to achieve full cell wall disruption of the plant cells.

[0012] (4) Heating and reflux extraction: The mixture after cell wall disruption is stirred and refluxed at 70-85℃ for 10-20 minutes.

[0013] (5) Three-phase separation and solvent reuse:

[0014] a. The extract is centrifuged at high speed while hot. Since the system contains oil, alcohol, water and fine solids, it naturally forms three distinct phases after centrifugation: the upper layer is the camellia oil phase enriched with oleanolic acid, the middle layer is the ethanol-water phase, and the lower layer is a small amount of residual solid phase.

[0015] b. Collect the upper oil phase, distill it under reduced pressure, and recover the trace amounts of ethanol and water dissolved in it to obtain primary camellia oil rich in oleanolic acid.

[0016] c. Collect the middle layer of ethanol-aqueous phase, add a small amount of fresh ethanol to the initial concentration, and then reuse it in step (3) as the extraction solvent for the next batch of materials. This step significantly reduces solvent consumption and wastewater discharge.

[0017] (6) Refining: Primary camellia oil is winterized and filtered at 4-7℃ to obtain refined functional camellia oil.

[0018] Preferably, the mass ratio of raw material A to B in step (2) is 1:15.

[0019] Preferably, in step (3), the ethanol concentration is 30% (v / v) and the material-to-liquid ratio is 1:3.

[0020] Preferably, the extraction temperature in step (4) is 80°C and the extraction time is 15 minutes.

[0021] The present invention also includes tea oil prepared by the method, wherein the oleanolic acid content in the tea oil is 40-60 mg / kg.

[0022] The mechanism of this invention is as follows:

[0023] This invention combines three key operations—"powerful cell wall disruption," "three-phase separation," and "solvent circulation"—with a specific concentration of ethanol-water solution to form a highly efficient, closed-loop extraction and enrichment system. In the initial extraction stage, a shearing device, such as a cell wall disruptor, is used for high-intensity shearing, physically and thoroughly disrupting the cell walls of camellia seeds and byproducts. This exposes oil droplets and intracellular contents (including oleanolic acid) to the solvent, significantly shortening the mass transfer distance and increasing the initial release rate and total amount. Using a low-concentration ethanol-water solution as the medium, during the heating and reflux stage, the dissolved oleanolic acid, due to its partition coefficient between the two phases, is transferred more extensively to the dispersed oil droplets in a dynamic equilibrium. The stable three-phase structure formed after centrifugation achieves clear product separation. The upper oil phase is the target enriched oil, with high purity and easy subsequent processing. The intermediate alcohol-aqueous phase is rich in incompletely transferred oleanolic acid and partially dissolved oily byproducts. After reuse, it can act as a "starter," increasing the initial concentration and mass transfer driving force of the target components in the next batch, forming a virtuous cycle and continuously improving overall extraction efficiency and solvent utilization. The recycling of the alcohol-aqueous phase significantly reduces solvent consumption compared to traditional single-extraction processes, making it economical and environmentally friendly.

[0024] The beneficial effects of this invention are as follows:

[0025] Due to the cell-wall disruption process and optimized solvent system, oleanolic acid exhibits high transfer efficiency from raw materials to the oil phase, resulting in a significant increase in oleanolic acid content in the finished oil (up to >40 mg / kg). Powerful cell-wall disruption greatly shortens the extraction time, resulting in a short overall process cycle. The solvent is recyclable, low-cost, and environmentally friendly: the unique three-phase separation design enables the recycling of the main extraction solvent, significantly reducing ethanol consumption and production costs, while also minimizing the discharge of organic wastewater. Oleanolic acid is uniformly enriched in the oil at a molecular level, resulting in a stable product system that is less prone to precipitation, and its inherent antioxidant properties contribute to improving the oxidative stability of the oil. The one-step process simultaneously completes the extraction, enrichment, and preliminary separation of multiple target products, simplifying the process. Attached Figure Description

[0026] Figure 1 This is the state before separation after the reaction in Example 1. The upper layer is the oil phase, the middle layer is the ethanol-water phase, and the lower layer is the solid residue. Detailed Implementation

[0027] The present invention will be further described below with reference to the embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0028] In the examples and comparative examples, the fresh camellia fruit shells used refer to the shells of mature camellia fruits harvested at the end of October. The blender used is a Mr9200 juicer.

[0029] The oil yield test method in the examples and comparative examples was based on the Chinese Pharmacopoeia 2025 edition, Part I, Loquat Leaf, General Chapter 0512.

[0030] Example 1 (Preferred embodiment of the present invention)

[0031] (1) Raw material pretreatment: Fresh camellia fruit shells are washed, drained, and then pulverized after vacuum freeze-drying to obtain freeze-dried powder A. The dried camellia seeds are pulverized to obtain seed powder B.

[0032] (2) Mix the freeze-dried powder of camellia fruit shell with the powder of camellia seed kernel (1:15).

[0033] (3) Add 1500 mL of 30% ethanol aqueous solution (material-liquid ratio 1:3) and use a high-speed blender (20000 rpm) to shear for 5 minutes.

[0034] (4) Transfer the mixture into the reactor and stir and reflux at 80°C for 15 minutes.

[0035] (5) While still hot, centrifuge at 3000 rpm for 20 minutes. The system clearly separates into three layers:

[0036] The upper oil phase was collected, winterized, and filtered. Trace amounts of solvent were removed under reduced pressure at 55°C to obtain primary camellia oil. The oleanolic acid content was determined to be 52.1 mg / kg, and the oil yield was 94%. The middle ethanol-aqueous phase was collected, and its volume and ethanol concentration were determined. A small amount of anhydrous ethanol was added to restore the concentration to 30% for use in the next batch extraction.

[0037] Comparative Example 1 (without cell wall breaking treatment)

[0038] Without performing the cell wall blending process in step (3), the mixture and solvent were directly added to the reactor to begin reflux extraction, with other conditions the same as in Example 1.

[0039] Results: Due to cell wall obstruction, the oil could not be effectively dissolved, and even extending the extraction time could not increase the oil yield. The oil yield was 87%, and the oleanolic acid content in the obtained camellia oil was 38.7 mg / kg. This demonstrates that cell wall disruption significantly improves the extraction rate and the enrichment efficiency of oleanolic acid.

[0040] Comparative Example 2 (Comparison of different ethanol concentrations)

[0041] Experiments were conducted using 20%, 30%, 40%, 50%, and 70% aqueous ethanol solutions, respectively, following the process described in Example 1 (including cell wall disruption). Except for the different ethanol concentrations, the other conditions were the same as in Example 1.

[0042] Results: The oleanolic acid content in camellia oil was 31.5, 52.1, 48.9, 40.2, and 17.8 mg / kg, with oil yields of 51%, 94%, 91%, 82%, and 45%, respectively. Under high concentrations of ethanol, the oil and solvent were miscible, making centrifugation difficult. A 30% ethanol concentration resulted in the best enrichment effect; excessively high or low concentrations were detrimental to the final enrichment of oleanolic acid in the oil phase.

[0043] Comparative Example 3 (Single-use solvent vs. cyclical use)

[0044] Scheme A (Comparative Example): In Example 1, the intermediate alcohol-aqueous phase is not recovered, and fresh solvent is used each time.

[0045] Scheme B (the present invention): In Example 1, the middle layer alcohol-aqueous phase is recovered, replenished, and recycled 5 times.

[0046] result:

[0047] Oleanolic acid content: The oleanolic acid content in the camellia oil obtained from the first to fifth batches of recycling was 52.1, 53.8, 55.0, 54.3, and 52.9 mg / kg, respectively. All of these values ​​remained at a high level and were slightly higher than the initial values, indicating that solvent recycling has a beneficial effect.

[0048] Solvent consumption: The total ethanol consumption of scheme B is only about 30% of that of scheme A.

[0049] Environmental friendliness: Option B significantly reduces wastewater discharge.

[0050] Example 2

[0051] (1) Raw material pretreatment: Fresh camellia fruit shells are washed, drained, and then pulverized after vacuum freeze-drying to obtain freeze-dried powder A. The dried camellia seeds are pulverized to obtain seed powder B.

[0052] (2) Mix the freeze-dried powder of camellia fruit shell with the powder of camellia seed kernel (1:20).

[0053] (3) Add 1500 mL of 30% ethanol aqueous solution (material-liquid ratio 1:3) and use a high-speed blender (20000 rpm) to shear for 5 minutes.

[0054] (4) Transfer the mixture into the reactor and stir and reflux at 80°C for 15 minutes.

[0055] (5) While still hot, centrifuge at 3000 rpm for 20 minutes. The system clearly separates into three layers:

[0056] The upper oil phase was collected, and trace amounts of solvent were removed under reduced pressure at 55°C to obtain primary camellia oil. The oleanolic acid content was determined to be 40.7 mg / kg, and the oil yield was 93%. The middle ethanol-aqueous phase was collected, and its volume and ethanol concentration were determined. A small amount of anhydrous ethanol was added to restore the concentration to 30% for use in the next batch extraction.

[0057] Example 3

[0058] (1) Raw material pretreatment: Fresh camellia fruit shells are washed, drained, and then pulverized after vacuum freeze-drying to obtain freeze-dried powder A. The dried camellia seeds are pulverized to obtain seed powder B.

[0059] (2) Mix the freeze-dried powder of camellia fruit shell with the powder of camellia seed kernel (1:15).

[0060] (3) Add 1500 mL of 25% ethanol aqueous solution (material-liquid ratio 1:3) and use a high-speed blender (20000 rpm) to shear for 5 minutes.

[0061] (4) Transfer the mixture into the reactor and stir and reflux at 80°C for 15 minutes.

[0062] (5) While still hot, centrifuge at 3000 rpm for 20 minutes. The system clearly separates into three layers:

[0063] The upper oil phase was collected, and trace amounts of solvent were removed under reduced pressure at 55°C to obtain primary camellia oil. The oleanolic acid content was determined to be 47.9 mg / kg, and the oil yield was 62.1% (reducing the ethanol concentration led to a decrease in oil yield and difficulty in demulsifying the system, but the oleanolic acid content did not change significantly; therefore, the preferred ethanol concentration in this invention is 30%-35%). The middle ethanol-aqueous phase was collected, and its volume and ethanol concentration were measured. A small amount of anhydrous ethanol was added to restore the concentration to 30% for use in the next batch extraction.

[0064] Example 4

[0065] (1) Raw material pretreatment: Fresh camellia fruit shells are washed, drained, and then pulverized after vacuum freeze-drying to obtain freeze-dried powder A. The dried camellia seeds are pulverized to obtain seed powder B.

[0066] (2) Mix the freeze-dried powder of camellia fruit shell with the powder of camellia seed kernel (1:15).

[0067] (3) Add 1500 mL of 35% ethanol aqueous solution (material-liquid ratio 1:3) and use a high-speed blender (20000 rpm) to shear for 5 minutes.

[0068] (4) Transfer the mixture into the reactor and stir and reflux at 80°C for 15 minutes.

[0069] (5) While still hot, centrifuge at 3000 rpm for 20 minutes. The system clearly separates into three layers:

[0070] The upper oil phase was collected, and trace amounts of solvent were removed under reduced pressure at 55°C to obtain primary camellia oil. The oleanolic acid content was found to be 50.5 mg / kg, and the oil yield was 87.3%. The middle ethanol-aqueous phase was collected, and its volume and ethanol concentration were determined. A small amount of anhydrous ethanol was added to restore the concentration to 30% for use in the next batch extraction.

[0071] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and substance defined by the claims of the present invention; and such modifications or substitutions are still within the scope defined by the claims of the present invention.

Claims

1. A method for preparing camellia oil rich in oleanolic acid, characterized in that, The steps are as follows: (1) Raw material pretreatment: Wash and drain the fresh camellia fruit shells and / or camellia tea leaves, freeze-dry them under vacuum and then pulverize them to obtain freeze-dried powder A. Pulverize the dried camellia seed kernels to obtain seed kernel powder B. (2) Raw material compounding: Mix freeze-dried powder A and kernel powder B evenly at a mass ratio of 1: (15-20); (3) Solvent-assisted cell wall breaking extraction: Add an ethanol aqueous solution with a volume concentration of 25%-35% to the mixed raw materials as the extraction solvent, and use a high-speed shearing device to stir and break the mixed system for 3-10 minutes; (4) Heating and reflux extraction: The mixture after cell wall disruption is stirred and refluxed at 70-85℃ for 10-20 minutes to obtain the extract; (5) Three-phase separation: The extract is centrifuged to separate the upper oil phase, and the solvent and water are removed to obtain camellia oil rich in oleanolic acid.

2. The method for preparing camellia oil rich in oleanolic acid according to claim 1, characterized in that, In step (3), the mass-volume ratio of the mixed raw materials to the extraction solvent is 1:(3-4), with units of g:mL.

3. The method for preparing camellia oil rich in oleanolic acid according to claim 1, characterized in that, The solvent described in step (5) is reused. The specific steps are as follows: a. The extract from step (4) is separated by high-speed centrifugation while it is still hot, and three phases are formed after centrifugation; b. Collect the upper oil phase, distill it under reduced pressure, and recover the trace amounts of ethanol and water dissolved in it to obtain primary camellia oil rich in oleanolic acid; c. Collect the middle layer of ethanol-water phase, add fresh ethanol to the initial concentration, and then reuse it in step (3) as the extraction solvent for the next batch of materials.

4. The method for preparing camellia oil rich in oleanolic acid according to claim 3, characterized in that, Camellia oil is obtained by winterizing and filtering primary camellia oil at 4-7℃.

5. The method for preparing camellia oil rich in oleanolic acid according to claim 1, characterized in that, In step (2), the mass ratio of freeze-dried powder A to kernel powder B is 1:

15.

6. The method for preparing camellia oil rich in oleanolic acid according to claim 1, characterized in that, In step (3), the ethanol concentration is 30% (v / v) and the material-to-liquid ratio is 1:

3.

7. The method for preparing camellia oil rich in oleanolic acid according to claim 1, characterized in that, In step (4), the extraction temperature is 80℃ and the extraction time is 15 minutes.

8. A camellia oil prepared by the method according to any one of claims 1-7, wherein the camellia oil contains 40-60 mg / kg of oleanolic acid.

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