Method for refining tea oil through cooperation of multiple physical fields and application of method

Abstract

The invention discloses a method for refining tea oil through cooperation of multiple physical fields and application of the method, and relates to the technical field of cosmetic processing. Crude camellia oil is prepared through combination of microwaves and infrared rays, and then the camellia oil essential oil is prepared through multiple times of decoloration treatment. The method maximally retains the natural flavor and nutrition of camellia seeds, and has the advantages of greenness and environmental protection. The camellia seed oil is high in oil yield and polyphenol content, micronutrients (vitamin E, sterol, squalene and the like) of camellia seeds are reserved to the greatest extent after decolorization, particularly polyphenol functional factors with high content and high activity are enriched, and the reproducibility is good, so that the obtained product is very suitable for the requirements of high-quality cosmetic oil. Production equipment used in the tea oil refining process is conventional equipment in existing grease processing enterprises, new equipment does not need to be added, investment is low, and the tea oil refining process is suitable for large-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of cosmetics processing, and in particular to a method for refining tea oil in a multi-physical field collaborative manner and application thereof. Background Art

[0002] Tea seed oil has important application value in the fields of edible oil and cosmetics because it is rich in active ingredients such as unsaturated fatty acids, vitamin E, and squalene.

[0003] Traditional processes for obtaining camellia crude oil primarily rely on steaming, frying, and pressing, extraction, and low-temperature cold pressing. The refining process typically involves water degumming, alkali refining and deacidification, water washing, filtration and decolorization, high-temperature steam deodorization, winterization and defatting, and finally the finished oil. This process presents several challenges: the high-temperature steaming, frying, and pressing process produces the carcinogen benzopyrene, while the extraction process results in solvent residues. Low-temperature cold pressing fails to destroy the outer protein and phospholipid membranes of the oil, and both processes result in the presence of large amounts of free fatty acids, ultimately increasing the acid value and subsequently generating large amounts of peroxides. Chemical refining, involving steps such as alkali refining and deacidification, and high-temperature steam deodorization, not only significantly reduces the content of nutrients such as vitamins and phytosterols in the finished oil, but also produces wastewater that pollutes the environment.

[0004] Chinese patent CN 10775332 A uses microwave pretreatment water extraction to prepare tea seed oil. Tea seed oil is obtained through microwave irradiation, constant temperature stirring, centrifugation and vacuum drying. Although this method has the advantages of no chemical solvent residue, environmental protection and avoidance of nutrient loss, it is expensive, takes a long time to prepare and has high industrial production costs. Chinese patent CN 116814331 A (A method for preparing and decolorizing camellia oil) uses high-temperature frying and pressing to prepare crude camellia oil. The oil is then treated with a decolorizer (60-80°C) and silica gel-expanded vermiculite-activated carbon (three-layer filtration with gradient cooling, 10-25°C / 20-30°C / -5-0°C) to obtain a clear, translucent refined oil with a golden to tender yellow color. This method effectively removes impurities from the camellia oil without requiring high-temperature deodorization, maximizing the retention of active substances in the oil. However, it produces the carcinogen benzopyrene, and suffers from issues such as a complex decolorization process, difficult-to-control production conditions, and incomplete decolorization, which reduces the quality of cosmetic-grade camellia seed oil.

[0005] The above problems make it difficult for the existing camellia oil production process to simultaneously meet the comprehensive requirements of nutrient retention, safety and industrial production.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for refining tea oil in a multi-physical field collaborative manner and its application to solve the above-mentioned technical problems.

[0008] The present invention is achieved in that: In a first aspect, an embodiment of the present invention provides a method for refining tea oil using a multi-physical field collaborative method, comprising the following steps: The camellia seeds were placed in a microwave field and treated at a power of 400 W to 1200 W for 0 min to 7 min; The microwave-treated camellia seeds are placed in an infrared field and treated at a temperature of 90°C to 160°C for 10 to 20 minutes. Camellia crude oil is obtained by extracting the infrared-treated camellia seeds. Camellia oil essential oil is obtained by decolorizing the camellia crude oil.

[0009] In a second aspect, an embodiment of the present invention provides a use of camellia essential oil prepared by the aforementioned method in the preparation of cosmetics.

[0010] In a third aspect, an embodiment of the present invention provides a cosmetic comprising camellia essential oil prepared by the aforementioned method.

[0011] The present invention has the following beneficial effects: The multi-physical field collaborative camellia oil refining method and its application provided in the embodiment of the present invention adopts microwave and infrared to produce camellia crude oil, and then produces camellia oil essential oil through multiple decolorization treatments; this method retains the natural flavor and nutrition of camellia seeds to the greatest extent, and has the advantages of being green and environmentally friendly. The camellia seed oil production of the present invention has a high oil yield and a high polyphenol content. After decolorization, the micronutrients (vitamin E, sterols, squalene, etc.) of the camellia seeds are retained to the greatest extent, and in particular, high-content, high-activity polyphenol functional factors are enriched, and the reproducibility is good, making the obtained product very suitable for the requirements of high-quality cosmetic oils. The production equipment used in the tea oil refining process of the present invention are all conventional equipment in existing oil processing enterprises, and no new equipment is required, with low investment and suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0013] Figure 1Photos of camellia oil obtained after different microwave times, infrared times, and decolorization: (A) from left to right: microwave time 0 min, 1 min, 2 min, 3 min, 4 min, 5 min, and 6 min; (B) from left to right: infrared time 4 min, 8 min, 12 min, 16 min, and 20 min; (C) from left to right: camellia crude oil, first camellia oil essential oil, second camellia oil essential oil, and third camellia oil essential oil; Figure 2 The 3D results of DPPH value and brightness value of camellia crude oil under three single factors: microwave time, infrared temperature and infrared time: (A) 3D surface plot of DPPH value of camellia crude oil under different microwave times; (B) 3D surface plot of DPPH value of camellia crude oil under different infrared temperatures; (C) 3D surface plot of DPPH value of camellia crude oil under different infrared times; (D) 3D surface plot of brightness value of camellia crude oil under different microwave times; (E) 3D surface plot of brightness value of camellia crude oil under different infrared temperatures and (F) 3D surface plot of brightness value of camellia crude oil under different infrared times. DETAILED DESCRIPTION

[0014] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0015] Camellia oil, one of China's oldest woody edible plant oils, is known as the "Oriental Olive Oil." Its medicinal value was first documented in the Compendium of Materia Medica: "Camellia oil has a cooling nature, cools blood, stops bleeding, clears heat and detoxifies. It treats liver blood deficiency, repels parasites, benefits the stomach, and improves eyesight." It also states, "Camellia seeds, bitter and fragrant, treat wheezing, coughs, and remove impurities." The Compendium of Materia Medica Supplement states that it possesses hemostatic, detoxifying, and antiseptic properties. Furthermore, numerous medical classics, including the Chinese Pharmacopoeia and the Dictionary of Traditional Chinese Medicine, list camellia oil as a traditional Chinese medicine. Research has shown that camellia oil is rich in unsaturated fatty acids and oleic acid, a composition very similar to olive oil. Therefore, it is considered a highly nutritious and relatively stable edible oil. Furthermore, it is rich in unsaponifiable substances such as polyphenols, phytosterols, and other functional components, contributing to its antioxidant, anti-obesity, antibacterial, anti-inflammatory, and anti-tumor properties. Camellia oil is also recommended by the Food and Agriculture Organization of the United Nations as a healthy edible oil.

[0016] Taking into account the technical difficulties associated with existing camellia oil production processes, the present invention provides an efficient camellia oil preparation and decolorization process. This process, while ensuring that the active substances in the camellia oil are not lost, completely decolorizes the oil and enables industrialized production using a simple and efficient refining method. The production equipment employed is conventional equipment found in existing oil processing companies, eliminating the need for new equipment, requiring minimal investment, and being suitable for large-scale production. Specific implementation methods are as follows: In a first aspect, an embodiment of the present invention provides a method for refining tea oil using a multi-physical field collaborative method, comprising the following steps: The camellia seeds were placed in a microwave field and treated at a power of 400 W to 1200 W for 0 min to 7 min; The microwave-treated camellia seeds are placed in an infrared field and treated at a temperature of 90°C to 160°C for 10 to 20 minutes. Camellia crude oil is obtained by extracting the infrared-treated camellia seeds. Camellia oil is obtained by decolorizing the camellia crude oil.

[0017] It should be noted that the embodiments of the present invention utilize microwave and infrared physics fields to pretreat camellia seeds. The combined use of these two technologies, with their complementary advantages, effectively promotes the dissolution of active substances during the extraction process, thereby improving the extraction efficiency of camellia oil. The process for refining camellia oil is simple, time-efficient, and highly safe, with easily controlled production conditions. It retains the active ingredients of the crude camellia oil to the greatest extent possible, is colorless and odorless, and is suitable for industrial production. The refined camellia essential oil can be used in cosmetic preparations.

[0018] In an optional embodiment, prior to using multi-physics field collaborative tea oil refining, the raw materials are pre-treated. Specifically, fresh camellia berries are picked and placed in a well-ventilated area to dry in the sun. Shelling is then performed using a shelling machine to obtain camellia seeds for later use. In other embodiments of the present invention, camellia berries that have been air-dried and free of mold and rot can also be selected for pre-treatment.

[0019] In an optional embodiment, the power of the microwave field is 750 W-850 W, and the microwave treatment time is 1 min-6 min.

[0020] It should be noted that the core characteristic of the microwave field is dielectric heating. Polar molecules (such as water, free fatty acids in oils and fats, phospholipids, etc.) generate heat through high-frequency polarization friction in the microwave alternating electric field, achieving rapid internal temperature rise, and may also induce the polarization or orientation effect of the electromagnetic field on the molecules; this is conducive to more uniform heating inside the camellia seeds, avoiding the destruction of active ingredients such as monounsaturated fatty acids (such as oleic acid) or vitamin E in the oils.

[0021] The present invention does not specifically limit the equipment for providing the microwave field, and the equipment can be reasonably selected according to the actual amount of material to be processed.

[0022] In an optional embodiment, the temperature of the infrared field is 120° C.-160° C., and the time of the infrared treatment is 12 min-16 min.

[0023] It should be noted that the core characteristic of the infrared field is thermal radiation heating, which produces a thermal effect through molecular vibration-rotation energy level transitions, directly heating the surface of the object and conducting it inward, which can quickly evaporate moisture and has the characteristics of precise temperature control, energy saving and high efficiency. Compared with traditional hot air drying, materials treated with infrared fields are heated evenly, which can effectively avoid local burning.

[0024] The present invention does not specifically limit the device for providing the infrared field, and the device can be reasonably selected based on the actual amount of material to be processed.

[0025] In an optional embodiment, after the infrared treatment, the camellia seeds are further crushed, and the particle size of the crushed camellia seeds is 10 mesh to 30 mesh.

[0026] It's important to note that the cell walls and membranes of camellia seeds can hinder the dissolution of ingredients. Crushing physically disrupts the cell structure, facilitating the release of intracellular oils, proteins, and other substances, thereby reducing extraction resistance. Moderate crushing prevents the deterioration of nutrients caused by high temperatures and reduces impurities (such as residual seed coats), while ensuring oil yield and purity. Crushing significantly increases the surface area of ​​the camellia seeds, allowing the extractant to more easily penetrate the raw material and fully interact with the oils and active ingredients. This is particularly true for target ingredients such as oils, polysaccharides, and polyphenols in camellia seeds. Smaller particle size significantly shortens extraction time and improves yield.

[0027] Uniform particle size can avoid local under-extraction or over-extraction due to uneven raw materials, reduce the amount of extractant used and the number of cycles, thereby reducing costs and environmental pressure.

[0028] The present invention does not specifically limit the equipment for crushing camellia seeds, and the equipment can be reasonably selected according to actual needs. The particle size of the crushed camellia seeds can be selected from any one of 10 mesh, 20 mesh and 30 mesh.

[0029] In an optional embodiment, during the extraction process, an extractant is added at a liquid-to-solid ratio of 1 mL / g to 10 mL / g to produce camellia crude oil.

[0030] The liquid-to-solid ratio in the present invention refers to the ratio between the extractant and the crushed camellia seeds. A reasonable setting of the liquid-to-solid ratio is conducive to sufficient infiltration of the raw materials, ensuring the dissolution of internal components; maintaining the concentration gradient of target components (such as oils, polyphenols, etc.) between the solvent and the raw materials to be extracted, promoting the diffusion of solutes from the solid phase to the liquid phase, promoting complete extraction and improving the yield.

[0031] If the liquid-to-solid ratio is too high, the amount of solvent used will increase, leading to higher energy consumption for recovery, evaporation, or processing. It may also lead to the extraction of more fat-soluble impurities (such as pigments and free fatty acids), increasing the refining burden. It may also dilute the solute concentration and increase subsequent concentration costs. If the liquid-to-solid ratio is too low, the solvent will saturate quickly, resulting in incomplete extraction and a lower yield.

[0032] In the embodiment of the present invention, the liquid-to-solid ratio can be reasonably adjusted according to the actual amount of material processed, and can be selected from any one of 1 mL / g, 3 mL / g, 4.5 mL / g, 5 mL / g, 7 mL / g and 10 mL / g, or other values ​​within the range of 1 mL / g-10 mL / g.

[0033] Furthermore, the extractant is selected from at least one of petroleum ether, ethanol, n-hexane, acetone and diethyl ether.

[0034] It should be noted that the extractant is the core medium for efficiently separating and enriching the target substance from its source system (such as a solution, solid, or gas). In this embodiment, camellia crude oil is extracted from camellia seeds. It must be immiscible or slightly soluble with the source solvent to form a stable two-phase system. A high-quality extractant avoids the introduction of new impurities, reducing the difficulty of subsequent purification. Furthermore, the extraction process eliminates the need for vigorous chemical reactions (such as acid-base neutralization and redox reactions), minimizing byproduct formation and enhancing the purity and safety of the target product.

[0035] Once the target substance reaches equilibrium between the two phases, separation can be achieved through simple layering (e.g., standing or centrifugation), avoiding complex separation steps. The extraction process is typically performed at or near room temperature, eliminating the need for high-temperature heating or low-temperature freezing, effectively preventing loss of the target substance due to thermal decomposition or freeze-crystallization. Furthermore, the separation speed after the two phases are layered is rapid, significantly shortening the process time.

[0036] In an optional embodiment, in order to ensure efficient and more complete extraction of camellia crude oil, the extractant is added and allowed to stand for an appropriate time. The number of extraction treatments can also be repeated 1-3 times depending on the actual amount of material to be processed. After the extraction is completed, the crude camellia crude oil obtained by extraction is filtered, concentrated, and centrifuged to obtain camellia crude oil.

[0037] In an optional embodiment, camellia crude oil is decolorized three times to obtain camellia essential oil.

[0038] It should be noted that if the amount of adsorbent used in a single decolorization process is too high, it may adsorb a large amount of target pigments and non-target components (such as nutrients). If the amount used is too low, the pigments may not be completely removed. Multiple decolorization treatments of camellia crude oil can selectively adsorb pigments from the oil while minimizing the adsorption loss of nutrients in the oil (such as vitamin E and monounsaturated fatty acids). Multiple decolorization processes can reduce the single adsorbent load pressure and improve overall decolorization efficiency by replacing or compounding the adsorbent in stages (such as using activated clay to remove non-polar pigments in the first step and activated carbon to remove residual polar pigments in the second step). Multiple decolorization processes reduce the total amount of adsorbent exposed in a single step, thereby reducing oil loss. Furthermore, the short, low-dose adsorption process is less destructive to heat-sensitive nutrients (such as vitamin E), thereby better preserving the nutritional value of the oil.

[0039] Specifically, the embodiment of the present invention adopts multiple decolorization treatments, which retains the micronutrients of camellia seeds (vitamin E, sterols, squalene, etc.) to the greatest extent, especially enriches high-content and highly active polyphenol functional factors, and has good reproducibility, making the resulting product very suitable for the requirements of high-quality cosmetic oils.

[0040] The decolorizing agents used in the three decolorization treatments are independently selected from at least one of activated carbon, diatomaceous earth, silica gel, macroporous resin, activated white clay and attapulgite.

[0041] In an optional embodiment, the mass ratio of camellia oil used in the first bleaching treatment to the first bleaching agent is 1:(0.03-0.08), further 1:0.06; the camellia oil used in the first bleaching treatment is camellia crude oil obtained by extraction treatment of camellia seeds; the camellia oil after the first bleaching treatment is recorded as the first camellia oil essential oil.

[0042] The mass ratio of camellia oil used in the second bleaching treatment to the second bleaching agent is 1:(0.2-0.8), and further 1:0.5; the camellia oil used in the second bleaching treatment is further bleached based on the camellia oil after the first bleaching treatment; the camellia oil after the second bleaching treatment is recorded as the second camellia oil essential oil.

[0043] The mass ratio of camellia oil to the third bleaching agent used in the third bleaching treatment is 1:(0.2-0.8), and further 1:0.5. The camellia oil used in the third bleaching treatment is further bleached based on the camellia oil after the second bleaching treatment; the camellia oil after the third bleaching treatment is recorded as the third camellia oil essential oil.

[0044] It should be noted that properly setting the ratio of the decolorizing agent to the raw material to be decolorized is beneficial for controlling mass transfer efficiency, balancing decolorization effect with oil loss, and reducing subsequent processing costs. It also ensures that the decolorizing agent is fully dispersed in the oil, shortens the time to reach adsorption equilibrium, and avoids the risk of oxidative rancidity caused by excessive contact time. In other embodiments of the present invention, the ratio of the decolorizing agent to the raw material to be decolorized can be reasonably adjusted according to actual needs.

[0045] If the amount of decolorizer is insufficient, the rate at which the pigment molecules diffuse to the adsorbent surface is slow, and the stirring or contact time needs to be extended (which may increase energy consumption or cause oxidation). If the amount of decolorizer is excessive, the gaps between the decolorizer particles decrease, the resistance to oil flow increases, and the mass transfer efficiency decreases (part of the adsorbent is not fully utilized).

[0046] In the embodiment of the present invention, camellia crude oil is subjected to multiple decolorization treatments. Different decolorizing agents are used in each decolorization process, and the ratio of the decolorizing agent to the oil to be decolorized is reasonably controlled. Under the comprehensive effect on the camellia crude oil, high-quality (light color, good nutrient retention), low-loss (less oil content, low nutrient loss), and high-efficiency (short process time, low energy consumption) camellia essential oil is finally refined.

[0047] In an optional embodiment, the first decolorizing agent is activated carbon and diatomaceous earth in a mass ratio of 1:(0.3-2).

[0048] It's important to note that if activated carbon is used alone for decolorization, its fine particles can easily clog filter cloth or paper, resulting in high filtration resistance, prolonged filtration time, and even the need for frequent cloth changes. While diatomaceous earth is a traditional filter aid, its ability to adsorb pigments is limited when used alone. When combined, the physical properties of the two synergistically improve filtration efficiency.

[0049] Specifically, activated carbon and diatomaceous earth have significantly different pore structures and surface properties. When combined, they can achieve phased and type-specific adsorption of different types of pigments, compensating for the limitations of a single adsorbent. Diatomaceous earth "dilutes" the surface polarity of activated carbon, reducing its nonspecific adsorption of nutrients. At the same time, the high specific surface area of ​​activated carbon compensates for diatomaceous earth's limited adsorption capacity for small-molecule pigments, ultimately achieving a balance of "efficient decolorization with minimal nutrient loss."

[0050] and / or, the second decolorizing agent is silica gel; And / or, the third decolorizing agent is a macroporous resin, preferably AB-8 macroporous resin.

[0051] In other embodiments of the present invention, the type of decolorizing agent can be reasonably adjusted according to actual needs.

[0052] In a second aspect, an embodiment of the present invention provides a use of camellia essential oil prepared by the aforementioned method in the preparation of cosmetics.

[0053] In a third aspect, an embodiment of the present invention provides a cosmetic comprising camellia essential oil prepared by the aforementioned method.

[0054] In summary, the method for refining tea oil using multi-physical fields in collaboration provided by the embodiment of the present invention comprises the following steps: (1) Raw material pretreatment The freshly picked camellia fruits are placed in a ventilated place to dry, and then shelled using a shelling machine to obtain camellia seeds.

[0055] (2) Microwave treatment The camellia seeds obtained in step (1) were placed in a microwave device and treated at a power of 400 W to 1200 W for 0 min to 7 min.

[0056] (3) Infrared processing The camellia seeds obtained in step (2) are placed in an infrared device and treated at a temperature of 90°C-160°C for 10 min-20 min.

[0057] (4) Extraction treatment The camellia seeds obtained in step (3) are crushed by a grinder and passed through a 10-30 mesh sieve to obtain camellia seed powder; The extractant is added at a liquid-solid ratio of 1 mL / g to 10 mL / g, the mixture is allowed to stand for 12 hours, and the extraction is repeated 1 to 3 times. The mixture is filtered, concentrated, and centrifuged to obtain camellia crude oil, which is recorded as microwave-infrared camellia crude oil.

[0058] (5) Decolorization The mass ratio of camellia oil to the first decolorizing agent used in the first decolorizing treatment is 1:(0.03-0.08); the first decolorizing agent is activated carbon and diatomaceous earth in a mass ratio of 1:(0.3-2); the treated camellia oil is recorded as the first camellia oil essential oil.

[0059] The mass ratio of camellia oil to the second decolorizing agent used in the second decolorizing treatment is 1:(0.2-0.8); the second decolorizing agent is silica gel; the treated camellia oil is recorded as the second camellia oil essential oil.

[0060] The mass ratio of camellia oil to the third decolorizing agent used in the third decolorizing treatment is 1:(0.2-0.8); the third decolorizing agent is AB-8 macroporous resin; the camellia oil after treatment is recorded as the third camellia oil essential oil.

[0061] It should be noted that, before the decolorization treatment, the first decolorizing agent and the third decolorizing agent need to be filled into the first chromatography column and the third chromatography column respectively.

[0062] The features and properties of the present invention are further described in detail below with reference to the examples. Petroleum ether in the following examples was purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0063] Example 1 This embodiment provides a camellia essential oil, and the refining method thereof comprises the following steps: (1) Raw material pretreatment The freshly picked camellia fruits are placed in a ventilated place to dry, and then shelled using a shelling machine to obtain camellia seeds.

[0064] (2) Microwave treatment 10 g of camellia seeds obtained in step (1) were placed in a microwave apparatus and treated at a power of 800 W for 290 s.

[0065] (3) Infrared processing The camellia seeds obtained in step (2) were placed in an infrared device and treated at a temperature of 140° C. for 14 minutes.

[0066] (4) Extraction treatment The camellia seeds obtained in step (3) were crushed by a grinder and passed through a 20-mesh sieve to obtain camellia seed powder; Petroleum ether was added at a liquid-to-solid ratio of 5 mL / g, and the mixture was allowed to stand for 12 h. The extraction was repeated twice, and the mixture was filtered, concentrated (to remove all petroleum ether), and centrifuged (5000 r / min, 10 min) to obtain camellia crude oil, which was recorded as microwave-infrared camellia crude oil.

[0067] (5) Decolorization treatment (primary decolorization treatment) Take 200 mL of the microwave-infrared camellia crude oil prepared in step (4), fill the first decolorizing agent activated carbon / diatomaceous earth (mass ratio of 1:2) into the first chromatography column, pass the microwave-infrared camellia crude oil through the first chromatography column for decolorization treatment, and the treated camellia oil is recorded as the first camellia oil essential oil; wherein, the mass ratio of microwave-infrared camellia crude oil to the first decolorizing agent is 1:0.06.

[0068] Example 2 This embodiment provides a camellia essential oil, the refining method of which differs from that of Example 1 only in that: (5) Decolorization treatment (two decolorization treatments) Take 200 mL of the microwave-infrared camellia crude oil prepared in step (4), fill the first decolorizing agent activated carbon / diatomaceous earth (mass ratio of 1:2) into the first chromatography column, and pass the microwave-infrared camellia crude oil through the first chromatography column for decolorization treatment. The treated camellia oil is recorded as the first camellia oil essential oil; wherein, the mass ratio of camellia crude oil to the first decolorizing agent is 1:0.06.

[0069] The first camellia oil essential oil is subjected to a second decolorization treatment: a second decolorizing agent, silica gel, is filled into a second chromatography column, and the first camellia oil essential oil prepared above is passed through the second chromatography column for decolorization treatment. The treated camellia oil is recorded as the second camellia oil essential oil; wherein, the mass ratio of the first camellia oil essential oil to the silica gel is 1:0.5.

[0070] Example 3 This embodiment provides a camellia essential oil, the refining method of which differs from that of Example 1 only in that: (5) Decolorization treatment (three-stage decolorization treatment) Take 200 mL of the microwave-infrared camellia crude oil prepared in step (4), fill the first decolorizing agent activated carbon / diatomaceous earth (mass ratio of 1:2) into the first chromatography column, and pass the microwave-infrared camellia crude oil through the first chromatography column for decolorization treatment. The treated camellia oil is recorded as the first camellia oil essential oil; wherein, the mass ratio of camellia crude oil to the first decolorizing agent is 1:0.06.

[0071] The first camellia oil essential oil is subjected to a second decolorization treatment: a second decolorizing agent, silica gel, is filled into a second chromatography column, and the first camellia oil essential oil prepared above is passed through the second chromatography column for decolorization treatment. The treated camellia oil is recorded as the second camellia oil essential oil; wherein, the mass ratio of the first camellia oil essential oil to the silica gel is 1:0.5.

[0072] The second camellia oil essential oil is subjected to a third decolorization treatment: a third decolorizing agent, AB-8 macroporous resin, is filled into a third chromatography column, and the second camellia oil essential oil prepared above is decolorized through the third chromatography column. The treated camellia oil is recorded as the third camellia oil essential oil; wherein, the mass ratio of the first camellia oil essential oil to the AB-8 macroporous resin is 1:0.5.

[0073] Comparative Example 1 This comparative example provides a camellia essential oil, the refining method of which differs from that of Example 1 only in that: Step (2) of microwave treatment is omitted, and step (5) of decolorization treatment is omitted.

[0074] The camellia oil prepared therefrom is recorded as infrared camellia crude oil.

[0075] Comparative Example 2 This comparative example provides a camellia essential oil, the refining method of which differs from that of Example 1 only in that: Step (3) infrared treatment is missing, and step (5) decolorization treatment is missing.

[0076] The prepared camellia oil is recorded as microwave camellia crude oil.

[0077] Comparative Example 3 This comparative example provides a camellia essential oil, the refining method of which differs from that of Example 1 only in that: Step (2) microwave treatment is missing, step (3) infrared treatment is missing, and step (5) decolorization treatment is missing.

[0078] The camellia oil obtained is recorded as conventional camellia crude oil.

[0079] Experimental Example 1 This experimental example analyzes the oil yield and composition of the microwave-infrared camellia crude oil prepared in Example 1, the infrared camellia crude oil prepared in Comparative Example 1, the microwave camellia crude oil prepared in Comparative Example 2, and the conventional camellia crude oil prepared in Comparative Example 3. The specific results are shown in Table 1. The test methods for the relevant items are as follows: (1) The test method for oil yield is as follows: First, weigh the round-bottom flask before extraction; after extracting the tea seed oil, weigh it and compare it with the weight of the tea seeds. The oil yield is calculated as follows:

[0080] (2) The acid value test is measured in accordance with the national standard GB5009.229-2016.

[0081] (3) The peroxide value is measured in accordance with the national standard GB5009.227-2023.

[0082] (4) The test method for total phenol content is as follows: Total phenolics were determined using the Flintol colorimetric method. 0.3 mL of the extract was diluted with 1 mL of ultrapure water, followed by 0.5 mL of Flintol solution and finally 1 mL of 10% Na₂CO₃ solution. The mixture was incubated in a 50°C water bath for 1 hour. The mixture was then cooled with running water and allowed to stand at room temperature for 30 minutes. The absorbance was measured at 745 nm. Polyphenols were expressed as mg GAE (gallic acid equivalents) per kg of oil.

[0083] (5) Determination of antioxidant capacity by DPPH and ABTS Prepare a 0.2 mM DPPH solution in anhydrous ethanol. Mix 0.2 mL of the extract with 1 mL of the DPPP solution, shake the mixture vigorously, and maintain it at room temperature for 30 minutes. Monitor the sample's absorbance at 517 nm. Mix 7 mM ABTS with 2.45 mM potassium persulfate (1:1) and incubate in the dark at room temperature for 12-16 hours. Dilute the mixture to an absorbance of 0.75 with ethanol. Finally, react 0.2 mL of the extract with 1 mL of the mixture at room temperature for 6 minutes, and measure the absorbance at 734 nm.

[0084] (6) The testing standard for squalene refers to LS / T 6120-2017.

[0085] Gas chromatography column: HP-5 capillary column (30 m, 0.32 mm, 0.25 μm), inlet temperature: 250°C; column temperature increased from 160°C to 220°C at a rate of 15°C / min, held for 2 min, then increased to 280°C at a rate of 5°C / min. The temperature was then increased to 280°C at a rate of 5°C / min, held for 20 min, and finally increased to 300°C at a rate of 5°C / min, held for 2 min. FID detector: temperature: 300°C, hydrogen flow rate: 40 mL / min, air flow rate: 450 mL / min, makeup gas flow rate: 30 mL / min.

[0086] (7) Determination of tocopherol content The determination of tocopherol content shall refer to GB 5009.82-2016.

[0087] The procedure is as follows: Weigh 0.5-2g of oil sample (accurate to 0.01g) into a 25mL brown volumetric flask, add 0.1g of BHT, and then add 10mL of mobile phase. Dissolve the mobile phase to the mark by ultrasonic or vortexing, then shake thoroughly. Place a 0.22μm organic filter into the brown injection bottle and prepare for injection.

[0088] Table 1 Analysis results of oil yield and composition

[0089] As can be seen from the results in Table 1, the oil yield of the conventional camellia crude oil in Comparative Example 3 was 32.63±0.59%. After microwave and infrared treatment, the oil yields of the microwave camellia crude oil in Comparative Example 2 and the infrared camellia crude oil in Comparative Example 1 increased by 8.05% and 5.07%, respectively. After combined microwave and infrared treatment, the oil yield of the microwave-infrared camellia crude oil prepared in Example 1 increased to 42.32%±0.71%, an increase of 9.69%. Compared with the microwave camellia crude oil in Comparative Example 2 and the infrared camellia crude oil in Comparative Example 1, the combined microwave-infrared treatment significantly increased the oil yield of camellia seeds from 1.64% to 4.88%, indicating that the combined microwave-infrared treatment promoted the release of oil from camellia seeds and increased the overall oil yield of camellia seeds. As can be seen from the above, appropriate heat treatment can increase oil yield; and suitable microwave and pulsed electric field conditions can increase the pore size of plant cells, thereby improving the extraction efficiency of camellia seed oil. However, excessively high temperatures may lead to excessive water loss, increase the brittleness of plant tissues, and hinder the extraction of camellia seed oil.

[0090] Acid value reflects the free fatty acid (FFA) content and indicates the degree of rancidity of the oil. The acid value of conventional camellia crude oil in Comparative Example 3 was 2.33 ± 0.06 mg KOH / g. After infrared treatment, the acid value of infrared camellia crude oil in Comparative Example 1 was 1.40 ± 0.10 mg KOH / g, and after microwave treatment, the acid value of microwave camellia crude oil in Comparative Example 2 was 1.87 ± 0.06 mg KOH / g. After combined microwave and infrared treatment, the acid value of camellia crude oil prepared in Example 1 was 2.03 ± 0.06 mg KOH / g (P < 0.05). As shown above, conventional camellia crude oil has the highest acid value, and different processing methods significantly affect acid value. The decrease in acid value may be due to the thermal inactivation of hydrolases and oxidases, particularly lipase and lipoxygenase, during high-temperature processing, which inhibits the production of free fatty acids.

[0091] Peroxide value is used to monitor oxidation and deterioration of vegetable oils during processing. Peroxide values ​​ranged from 0.33 ± 0.02 meq O2 / kg to 0.55 ± 0.03 meq O2 / kg. Although the peroxide value of the camellia crude oil prepared in Example 1 was higher than that of the microwave-treated camellia crude oil in Comparative Example 2 and the conventional camellia crude oil in Comparative Example 3, the content of each component after processing was still well below the generally accepted upper limit for edible oils, indicating no significant oxidation or deterioration. The varying degrees of increase in peroxide value may be attributed to the reaction of free radicals with the unsaturated fatty acids in the oil and the subsequent accumulation of primary oxidation products. Moreover, under prolonged baking conditions, these unstable primary oxidation products may further decompose into secondary oxidation products such as aldehydes, ketones, hydroxyepoxides, and epoxy hydroperoxides.

[0092] Total phenolic acid (TPC) content is a key indicator of high-quality edible oil. Therefore, the present invention measured changes in TPC under different treatment conditions. Compared with conventional camellia crude oil in Comparative Example 3, both microwave treatment in Comparative Example 2 and infrared treatment in Comparative Example 1 significantly increased TPC content. Specifically, TPC increased from 112.73±2.47 mg GAE / kg oil in the conventional camellia crude oil in Comparative Example 3 to 168.26±2.45 mg GAE / kg oil in the microwave-treated group in Comparative Example 2; under infrared treatment in Comparative Example 1, TPC increased to 128.02±4.38 mg GAE / kg oil. Notably, the combined microwave and infrared treatment in Example 1 reached TPC levels of 204.11±5.04 mg GAE / kg oil, 1.8 times that of Comparative Example 3. Clearly, the enhanced TPC effect of combined microwave and infrared treatment in Example 1 was more pronounced than that of microwave or infrared treatment alone (p<0.05). This increase in TPC is likely due to the disruption of molecular bonds within the cell matrix and the enhanced solubility of phenolic compounds at high temperatures, which promotes their release.

[0093] The antioxidant capacity of camellia oil was further evaluated using DPPH and ABTS free radical scavenging experiments. The DPPH and ABTS values ​​of conventional camellia oil in Comparative Example 3 were only 10.39% ± 0.32% and 3.68% ± 0.55%, respectively. Microwave treatment in Comparative Example 2 or infrared treatment in Comparative Example 1 significantly improved the antioxidant capacity of camellia oil (p < 0.05): DPPH activity increased 1.49-fold under infrared treatment, 1.79-fold under microwave treatment, and 2.02-fold under combined microwave and infrared treatment in Example 1 (p < 0.05). ABTS activity also increased 1.89-fold under infrared treatment, 3.95-fold under microwave treatment, and 5.04-fold after combined microwave and infrared treatment in Example 1. These results indicate that combined microwave and infrared treatment effectively enhances the antioxidant activity of camellia oil compared to microwave or infrared treatment alone. Under certain conditions, microwave treatment alone can improve the antioxidant capacity of camellia oil more than infrared treatment alone. This significant improvement may be due to the increased release of pigments and phenolic compounds into the oil phase during microwave treatment, which indirectly promotes the enhancement of antioxidant activity.

[0094] Tocopherol (vitamin E) is one of the most potent fat-soluble antioxidants essential for human nutrition and plays a key role in preventing age-related and cardiovascular diseases. After microwave treatment in Comparative Example 2, the vitamin E content in camellia oil showed a downward trend (P < 0.05). In contrast, infrared treatment in Comparative Example 1 resulted in a more significant change in vitamin E levels, reaching a high of 13.95 mg / 100 g. Notably, the vitamin E content in Example 1 after microwave and infrared treatment decreased slightly from that in Comparative Example 3 (14.05 mg / 100 g), reaching 13.55 mg / 100 g. These results indicate that microwave and infrared treatments have little effect on vitamin E content.

[0095] Comparative Example 1, treated with infrared, achieved the highest squalene content (158.05 mg / kg). Comparative Example 2, treated with microwaves, achieved a decreasing squalene content of 142.65 mg / kg. This decrease may be attributed to squalene's relatively low thermal stability, which makes it susceptible to oxidation and degradation during heat treatment. Interestingly, the combined microwave and infrared treatment in Example 1 increased the squalene content to 152.15 mg / kg. This increase may be due to the enhanced release of bound squalene from the oil matrix at infrared wavelengths. The squalene content in camellia oil obtained by the combined microwave and infrared method was significantly higher than the 30.4 mg / kg reported by supercritical fluid extraction (Dan Zhou, Qinlong Shi, Jiangbo Pan, Min Liu, Yi Long, Fahuan Ge. Effectively improve the quality of camellia oil by the combinationof supercritical fluid extraction and molecular distillation (SFE-MD) [J]. LWT-Food Science and Technology, 2019, 110:18), indicating that combined microwave and infrared treatment may be a more effective strategy to retain or increase the squalene content in camellia oil.

[0096] Experimental Example 2 This experimental example analyzed the main volatile components of the microwave-infrared camellia crude oil produced in Example 1, the infrared camellia crude oil produced in Comparative Example 1, the microwave camellia crude oil produced in Comparative Example 2, and the conventional camellia crude oil produced in Comparative Example 3. It should be noted that volatile compounds in edible oils are primarily composed of aldehydes, ketones, and alcohols, which are typically formed during the oxidative decomposition of fatty acids and the subsequent decomposition of hydroperoxides. This experimental example used gas chromatography-mass spectrometry (GC-MS) to analyze the changes in volatile components of camellia oil extracted using different pretreatment methods. The relevant results are shown in Table 2. The analysis method is as follows: Accurately weigh 1 g of oil sample and place it in a 20 mL headspace vial. Add 2 μL of internal standard (cyclohexanol) and seal the vial with a cap. The gas chromatography-mass spectrometry autosampler was programmed to equilibrate at 40°C for 20 minutes. Extract the flavor components using a 1 cm 50 / 30 μm DVB / CAR / PDMS extraction tip for 30 minutes. The tip was then inserted into the gas chromatograph inlet and analyzed at 250°C for 5 minutes. Each oil sample was analyzed in triplicate.

[0097] Table 2 Analysis results of main volatile substances and their contents

[0098] Note: “ns” in the table means the corresponding substance was not detected.

[0099] As shown in Table 2, based on mass spectral library matching and manual verification, a total of 69 major volatile compounds were identified. Conventional camellia crude oil contained 6 aldehydes, 8 alcohols, 4 acids, 6 esters, 5 ketones, 1 olefin, and 2 heterocyclic compounds. By molecular weight alone, 13 aldehydes, 9 alcohols, 7 acids, 6 esters, 4 ketones, 2 olefins, and 9 heterocyclic compounds were identified. Infrared treatment revealed 10 aldehydes, 9 alcohols, 3 acids, 6 esters, 4 ketones, 1 olefin, and 4 heterocyclic compounds in the camellia crude oil. Combined microwave-infrared treatment revealed 15 aldehydes, 7 alcohols, 2 acids, 5 esters, 6 ketones, 1 olefin, and 7 heterocyclic compounds in the camellia crude oil. Microwave-infrared treatment alone revealed the highest diversity of volatile compounds (50). However, the combined microwave and infrared treatment produced the highest number of aldehydes (15) and ketones (6), indicating its advantage in producing specific types of flavor compounds. The total number of volatile compounds in the combined microwave and infrared treatment was between that in the microwave and infrared treatments alone, indicating that this was an optimized synergistic effect rather than a simple additive result.

[0100] Further analysis revealed that combined microwave and infrared treatment promoted the formation of key thermal reaction products, such as 2,5-dimethylpyrazine and phenylacetaldehyde, which are well-recognized hallmarks of toasted and caramel-like aromas. These compounds indicate that the Maillard reaction and lipid oxidation processes are intensified under combined heating, significantly contributing to the increased flavor complexity. Although the total number of volatiles in the combined microwave and infrared treatment group was slightly lower than that of volatiles treated with microwave or infrared alone, the combined microwave and infrared treatment group had the highest number of aldehydes and ketones, and the abundance of heterocyclic compounds was also relatively high. This indicates that the combined treatment has a stronger ability to produce key flavor categories, enriching the depth and complexity of the aroma profile.

[0101] Among all volatile classes, aldehydes dominated, and their content was significantly affected by treatment conditions, increasing from 4.71% in conventional camellia crude oil to 33.0% in microwave-treated camellia crude oil. Due to their low odor threshold, aldehydes are considered key contributors to the overall aroma and function as effective aroma modulators. Infrared camellia crude oil resulted in significant increases in octoxybenzaldehyde, nonanal, and phenylacetaldehyde. Interestingly, after combined microwave and infrared treatment, the contents of furfural, benzaldehyde, and phenylacetaldehyde in the microwave-IR camellia crude oil increased significantly compared to those in microwave or infrared treatment, while the contents of octoxybenzaldehyde and nonanal decreased significantly compared to microwave or infrared treatment, indicating the transformation and redistribution of specific aldehydes during the enhanced thermal process.

[0102] Alcohol volatiles were the second most abundant volatile component, with concentrations ranging from 3.84% to 23.94% after different treatments. However, due to their relatively high odor thresholds, their direct contribution to the overall aroma was limited. For example, n-heptanol and octanol had the least impact on the sensory properties of tea oil. After combined microwave and infrared treatment, the content of short-chain alcohols, particularly pentanol, n-heptanol, and 1-hepten-3-ol, decreased. Furthermore, furfural was only present in the combined microwave and infrared treatment group, likely due to its thermal degradation into the corresponding aldehydes and ketones upon prolonged or high-intensity heating.

[0103] Heterocyclic compounds such as pyrazines and furans were also identified. These compounds are typically produced through the Maillard reaction or the thermal degradation of amino acids at different heat intensities. The relative abundance of these compounds was significantly higher in the combined microwave and infrared treatment compared to conventional camellia crude oil. Notably, the levels of most heterocyclic compounds in the combined microwave and infrared treatment exceeded those observed in the microwave or infrared treatment alone.

[0104] In summary, combined microwave and infrared heating promoted the formation of desirable thermal degradation products, more effectively enhancing the production of flavor compounds and the sensory appeal of camellia oil. Therefore, combined microwave and infrared treatment is a promising flavor optimization method and provides a valuable strategy for improving the sensory quality of camellia oil.

[0105] Experimental Example 3 This experimental example analyzed the brightness and composition of the microwave-infrared camellia oil and the first camellia oil prepared in Example 1, the second camellia oil prepared in Example 2, and the third camellia oil prepared in Example 3. The specific results are shown in Table 3. The analysis method is as follows: (1) Color The color of the oil was recorded using a Hunter UltraScan VIS colorimeter (Hunter Associates, USA). The units of color measurement are L* (from dark (0) to light (100)), a* (from green (-a*) to red (+a*)), and b* (from blue (-b*) to yellow (+b*)).

[0106] (2) Fatty acid composition Accurately weigh 80 mg (0.001 g) of tea oil in a centrifuge tube, add 0.5 mL of 0.5 M sodium methoxide and 2.5 mL of n-hexane, vortex for 5 min and 5000 rpm for 10 min, take the supernatant, and inject the supernatant into a gas chromatograph with a flame ionization detector for quantitative determination of fatty acid content.

[0107] Measurement conditions: The chromatographic column was a DB-FFAP column (30 m inner diameter × 250 μm, 0.25 μm thickness). The injector and detector temperatures were set at 250°C and 300°C, respectively. The nitrogen flow rate was 1.5 mL / min, with a split ratio of 80:1. The column chamber temperature was maintained at 130°C for 3 minutes, then increased to 200°C at a rate of 5°C / min and held for 10 minutes. Finally, it was increased to 220°C at a rate of 2°C / min and held for 3 minutes.

[0108] Table 3 Analysis results of brightness and composition

[0109] Note: Different letters in the same row, such as a, b, c, d, ab and bc, indicate significant differences (p<0.05).

[0110] from Figure 1 As shown in Table 3, L values ​​ranged from 79.09 to 4.18, a* values ​​from -7.01 to -10.44, b* values ​​from 34.31 to 114.85, red values ​​from 0.6 to 1.3, and yellow values ​​from 3.2 to 23.1. Compared with the microwave-infrared camellia oil crude oil, all three color parameters (L*, a*, b*, redness, and yellowness) showed significant changes after three bleaching cycles (P < 0.05). Compared with the first and second camellia oils, the third camellia oil had the highest L value, and significantly decreased a*, b*, redness, and yellowness, demonstrating superior bleaching performance. Total phenol values ​​ranged from 85.66 to 204.11, and DPPH values ​​ranged from 2.28 to 21.01. Compared with the camellia oil crude oil, total phenol and DPPH values ​​decreased after three bleaching cycles, but their contents and antioxidant capacity remained high.

[0111] Fatty acids, as important components of oils and fats, are key indicators for evaluating the nutritional quality, stability, and physicochemical properties of edible oils. As shown in Table 3, different heat treatment methods affected the fatty acid composition of the samples to varying degrees. Oleic acid (C18:1), a monounsaturated fatty acid (MUFA), accounted for over 81% of the total fatty acids in all crude camellia oils. C18:1 content increased slightly across all treatments, reaching a peak of 82.66% in the second camellia oil, likely due to the degradation of polyunsaturated fatty acids (PUFAs). PUFA content decreased significantly with increasing treatment intensity, from 6.71% in the crude camellia oil to 6.44% in the second camellia oil. However, the third camellia oil showed similar levels to the second camellia oil, suggesting that PUFAs were adsorbed during the bleaching process. In contrast, saturated fatty acids (SFAs), including palmitic acid (C16:0) and stearic acid (C18:0), remained relatively stable during treatment, with only minor fluctuations, indicating their greater stability compared to unsaturated fatty acids. Compared to the crude camellia oil, the third camellia oil essential oil showed a 0.81% decrease in SFA, a 0.10% increase in PUFA, and a 0.88% increase in MUFA. Although bleaching caused some changes in the fatty acid composition, the overall changes remained relatively limited. These results indicate that the essential nutritional characteristics of the crude camellia oil were retained after bleaching.

[0112] Vitamin E is one of the most potent fat-soluble antioxidants essential for human nutrition and plays a key role in preventing age-related and cardiovascular diseases. After decolorization, vitamin E content showed a decreasing trend (P < 0.05). Notably, the vitamin E content of the first and second camellia oils (11.00 mg / 100 g) was slightly lower than that of the original camellia oil (13.55 mg / 100 g), while the third camellia oil reached 10.60 mg / 100 g, a slight decrease from the first and second camellia oils, but the change was not significant. These results indicate that three decolorization treatments had little effect on vitamin E content.

[0113] The highest squalene content (150.8 mg / kg) was achieved without bleaching. After three bleaching treatments, the squalene content decreased to 131.7 mg / kg, showing a smaller decrease. This decrease may be attributed to squalene's relatively low stability, which makes it susceptible to oxidation and degradation during adsorption and desorption. However, the squalene content in bleached camellia oil was significantly higher than the 89.24 mg / kg reported in the patent (CN 116590089 A), suggesting that three bleaching treatments may be a more effective strategy for preserving squalene in tea oil.

[0114] Test Example 1 This experimental example investigates the effect of microwave treatment time on the refining of camellia crude oil. The refining method differs from that of Example 1 as follows: the refining method does not involve infrared treatment or decolorization of camellia crude oil; (2) Microwave treatment 10 g of camellia seeds obtained in step (1) were placed in a microwave apparatus and treated at a power of 800 W for 1 min, 2 min, 3 min, 4 min, 5 min and 6 min, respectively.

[0115] The oil yield and composition of microwave camellia crude oil prepared by microwave treatment for different times were analyzed. The specific results are shown in Table 4.

[0116] Table 4 Analysis results of oil yield and composition of microwave camellia crude oil prepared at different microwave treatment times

[0117] From the results in Table 4, it can be seen that with the increase of microwave time, the oil yield, total phenol content (TPC), and free radical scavenging ability (DPPH and ABTS) of the obtained camellia oil all showed an increasing trend. Among them, the increase in the values ​​of various indicators of camellia oil obtained at microwave times of 5 min and 6 min was significant.

[0118] Test Example 2 This experimental example investigates the effect of infrared treatment temperature on the refining of camellia crude oil. The refining method differs from that of Example 1 as follows: the refining method does not involve microwave treatment or decolorization of camellia crude oil; (3) Infrared processing 10 g of camellia seeds obtained in step (1) were placed in an infrared device and treated at temperatures of 80°C, 100°C, 120°C, 140°C and 160°C for 12 min, respectively.

[0119] The oil yield and composition of infrared camellia crude oil prepared at different infrared treatment temperatures were analyzed. The specific results are shown in Table 5.

[0120] Table 5 Analysis results of oil yield and composition of infrared camellia crude oil obtained at different infrared treatment temperatures

[0121] As can be seen from the results in Table 5, with the increase of infrared temperature, the oil yield of the obtained camellia oil ranged from 30.37% to 34.58%, showing a trend of first increasing and then decreasing. However, the total phenol content (TPC) and free radical scavenging ability (DPPH and ABTS) both showed a gradual increase. Among them, the values ​​of various indicators of camellia oil obtained at microwave temperatures of 140°C and 160°C increased significantly.

[0122] Test Example 3 This experimental example investigates the effect of infrared treatment time on the refining of camellia crude oil. The refining method differs from that of Example 1 as follows: the refining method does not involve microwave treatment or decolorization of camellia crude oil; (3) Infrared processing 10 g of camellia seeds obtained in step (1) were placed in an infrared device and treated at a temperature of 140°C for 4 min, 8 min, 12 min, 16 min and 20 min respectively.

[0123] The oil yield and composition of infrared camellia crude oil prepared with different infrared treatment times were analyzed. The specific results are shown in Table 6.

[0124] Table 6 Analysis results of oil yield and composition of infrared camellia crude oil obtained at different infrared treatment times

[0125] From the results in Table 6, it can be seen that with the increase of infrared treatment time, the oil yield (Oilyield) of the obtained camellia oil ranged from 38.10% to 39.27%, with no significant change; however, the total phenol content (TPC) and free radical scavenging ability (DPPH and ABTS) showed a gradual increasing trend, among which the values ​​of various indicators of camellia oil obtained at microwave temperatures of 16 min and 20 min increased significantly.

[0126] Test Example 4 This test example screened the oil yield, total phenol content and DPPH value under the three single factors of microwave time, infrared temperature and infrared time in Test Examples 1-3. Finally, we selected microwave time of 4 min, 5 min and 6 min; infrared temperature of 120°C, 140°C and 160°C; infrared time of 12 min, 16 min and 20 min; and ran and fitted according to Design-Expert software, resulting in 17 runs. The specific scheme is shown in Tables 7 and 8.

[0127] Table 7 Level changes of oil yield, total phenol content and DPPH value in conditional screening under the three single factors of microwave time, infrared temperature and infrared time

[0128] Table 8 DPPH value and brightness value of camellia crude oil obtained under three single factors: microwave time, infrared temperature, and infrared time

[0129] Table 9 Quadratic model of DPPH value and brightness value of camellia crude oil under the three single factors of microwave time, infrared temperature and infrared time

[0130] Note: “-” in the table means that the corresponding data of the relevant items were not detected.

[0131] Table 10 ANOVA model of DPPH value and brightness value of camellia crude oil under the three single factors of microwave time, infrared temperature and infrared time

[0132] Note: Significant differences are indicated by * p<0.05, ** p<0.001, *** p<0.0001; “-” in the table indicates that the corresponding data of the relevant items were not detected.

[0133] The 3D results of DPPH value and brightness value of camellia crude oil under the three single factors of microwave time, infrared temperature and infrared time are shown in Figure 2 : (A) 3D surface diagram of DPPH values ​​of camellia crude oil obtained at different microwave times, (B) 3D surface diagram of DPPH values ​​of camellia crude oil obtained at different infrared temperatures, (C) 3D surface diagram of DPPH values ​​of camellia crude oil obtained at different infrared times, (D) 3D surface diagram of brightness values ​​of camellia crude oil obtained at different microwave times, (E) 3D surface diagram of brightness values ​​of camellia crude oil obtained at different infrared temperatures and (F) 3D surface diagram of brightness values ​​of camellia crude oil obtained at different infrared times.

[0134] Combined with Table 7-10 and Figure 2 It can be seen that microwave has a greater effect on the antioxidant index of oil-associated products than infrared, and the effect on brightness is the same; then, referring to the quadratic model (Table 9), the adjusted regression coefficients were used to determine whether the linear relationship between antioxidant value, brightness and pretreatment was close to 1. The adjusted regression coefficients were 0.9700 and 0.9362, respectively, as shown in Table 8, indicating that the antioxidant value and brightness evaluation were reliable data in the combined processing.

[0135] We further investigated the interaction between the ANOVA model for DPPH and brightness (Table 10), the equations corresponding to the proposed method, and the application of each dependent variable in the ANOVA results. Combined with a second-order regression model, we found that the P values ​​for the antioxidant value and brightness models were both less than 0.05, indicating statistical significance, as shown in Table 8. Using Design Expert software, we determined the optimal parameters for antioxidant extraction: microwave time 4.89 min, infrared temperature 147.63°C, and infrared time 14.11 min; while the optimal parameters for brightness were microwave time 5.01 min, infrared temperature 120.31°C, and infrared time 19.75 min. Based on the actual conditions and 3D graphics, the optimal parameters for this embodiment of the present invention were set as follows: microwave time 290 s, infrared temperature 140.00°C, and infrared time 14.00 min.

[0136] In summary, the multi-physical field collaborative tea oil refining method and its application provided by the embodiment of the present invention adopts microwave and infrared to produce camellia crude oil, and then produces camellia oil essential oil through multiple decolorization treatments; this method retains the natural flavor and nutrition of camellia seeds to the greatest extent, and has the advantages of being green and environmentally friendly. The camellia seed oil production of the present invention has a high oil yield (up to 42.32 grams of oil / 100g of camellia seeds) and a high polyphenol content (up to 204.11 mg / kg). After decolorization, the micronutrients of camellia seeds (vitamin E, sterols, squalene, etc.) are retained to the greatest extent, and high-content, high-activity polyphenol functional factors are especially enriched, and the reproducibility is good, making the obtained product very suitable for the requirements of high-quality cosmetic oils. The production equipment used in the tea oil refining process of the present invention are all conventional equipment in existing oil processing enterprises, and no new equipment is required, with low investment and suitable for large-scale production.

[0137] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for refining tea oil by using multiple physical fields, characterized in that: The steps include: The camellia seeds were placed in a microwave field and treated at a power of 400 W to 1200 W for 0 min to 7 min; The microwave-treated camellia seeds are placed in an infrared field and treated at a temperature of 90°C to 160°C for 10 to 20 minutes. Camellia crude oil is obtained by extracting the infrared-treated camellia seeds. Camellia oil essential oil is obtained by decolorizing the camellia crude oil.

2. The method according to claim 1, characterized in that The power of the microwave field is 750 W-850 W, and the microwave treatment time is 1 min-6 min.

3. The method according to claim 1, characterized in that The temperature of the infrared field is 120°C-160°C, and the time of infrared treatment is 12 min-16 min.

4. The method according to claim 1, wherein After the infrared treatment, the camellia seeds are crushed, and the particle size of the crushed camellia seeds is 10 meshes to 30 meshes.

5. The method according to claim 1, wherein In the extraction process, the extractant is added at a liquid-to-solid ratio of 1 mL / g to 10 mL / g to obtain camellia crude oil; Preferably, the extractant is selected from at least one of petroleum ether, ethanol, n-hexane, acetone and diethyl ether.

6. The method according to claim 1, wherein Camellia oil is obtained by three bleaching treatments of camellia crude oil; The decolorizing agents used in the three decolorization treatments are independently selected from at least one of activated carbon, diatomaceous earth, silica gel, macroporous resin, activated white clay and attapulgite.

7. The method according to claim 6, characterized in that The mass ratio of camellia oil to the first decolorizing agent used in the first decolorization treatment is 1:(0.03-0.08), preferably 1:0.06; The mass ratio of camellia oil to the second decolorizing agent used in the second decolorizing treatment is 1:(0.2-0.8), preferably 1:0.5; The mass ratio of camellia oil to the third decolorizing agent used in the third decolorization treatment is 1:(0.2-0.8), preferably 1:0.

5.

8. The method according to claim 7, characterized in that The first decolorizing agent is activated carbon and diatomaceous earth in a mass ratio of 1: (0.3-2); and / or, the second decolorizing agent is silica gel; And / or, the third decolorizing agent is a macroporous resin, preferably AB-8 macroporous resin.

9. Use of camellia essential oil prepared by the method according to any one of claims 1 to 8 in the preparation of cosmetics.

10. A cosmetic, characterized in that: The invention comprises camellia essential oil prepared by the method according to any one of claims 1 to 8.

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