Camellia seed compound oil and preparation method thereof

Abstract

The application provides a camellia oleifera seed compound oil and a preparation method thereof, and belongs to the technical field of plant oil refining. The application provides a preparation method of the camellia oleifera seed compound oil, which comprises the following steps: first mixing camellia oleifera seed crude oil and an acid solution to perform a degumming reaction to obtain degummed oil; second mixing the degummed oil and an alkaline solution to perform an acid removal reaction to obtain acid-removed oil; third mixing the acid-removed oil and an adsorption decolorizing agent to perform decolorization to obtain decolorized oil; introducing nitrogen into the decolorized oil to perform deodorization under vacuum to obtain refined oil; fourth mixing the degummed oil and the refined oil to obtain the camellia oleifera seed compound oil; and the mass of the degummed oil is 10-70% of the total mass of the refined oil and the degummed oil during the fourth mixing. The camellia oleifera seed degummed oil is compounded with the camellia oleifera seed refined oil, so that the oxidation stability and the active ingredient content of the camellia oleifera seed refined oil can be improved.

Description

Technical Field

[0001] This invention belongs to the field of vegetable oil refining technology, specifically relating to a camellia seed compound oil and its preparation method. Background Technology

[0002] Camellia oleifera belongs to the genus Camellia in the family Theaceae and is widely cultivated in Hunan, Jiangxi, Zhejiang, Guangxi, Fujian, and Anhui provinces of my country. Camellia seed oil, extracted from camellia seeds, is rich in bioactive components such as sterols, squalene, and polyphenols, and has high nutritional value. Therefore, it is widely used in functional foods, cosmetics, and pharmaceuticals.

[0003] In actual production, crude camellia seed oil of different qualities needs to undergo different degrees of degumming, deacidification, decolorization and deodorization to improve its quality. However, after these refining processes, the active ingredients in the oil are lost in large quantities and the oxidative stability decreases significantly. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a camellia seed compound oil and its preparation method. The camellia seed compound oil provided by this invention has a high content of active ingredients and strong oxidative stability.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing a compound oil from camellia seeds, comprising the following steps:

[0007] The crude oil from camellia seeds is first mixed with an acidic solution to carry out a degumming reaction, resulting in degummed oil.

[0008] The degummed oil is mixed with an alkaline solution to carry out a deacidification reaction, thereby obtaining deacidified oil;

[0009] The deacidified oil is mixed with the third adsorption and decolorizing agent for decolorization to obtain decolorized oil;

[0010] Nitrogen gas is introduced into the decolorized oil, and deodorization is carried out under vacuum conditions to obtain refined oil.

[0011] The degummed oil is mixed with the refined oil to obtain camellia seed compound oil;

[0012] In the fourth mixing, the mass of the degumming oil is 10-70% of the total mass of the refined oil and the degumming oil.

[0013] Preferably, the crude camellia seed oil is obtained by pressing camellia seeds; the camellia seeds are refrigerated and stored at a temperature of 2-8°C.

[0014] Preferably, the acidic solution is a phosphoric acid solution or a citric acid solution; the mass concentration of the phosphoric acid solution is 65-85%; the mass concentration of the citric acid solution is 30-50%; and the mass of the acidic solution is 0.1-0.5% of the mass of crude camellia seed oil.

[0015] Preferably, the degumming reaction is carried out at a temperature of 50–90°C for 10–50 minutes.

[0016] Preferably, the alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution; the mass concentration of the alkaline solution is 6-14%; the temperature of the deacidification reaction is 50-90°C, and the time is 10-50 min.

[0017] Preferably, the adsorption and decolorizing agent is a mixture of activated carbon and activated clay, or a mixture of activated carbon and bentonite; the mass ratio of activated carbon to activated clay is 1:(6-20); the mass ratio of activated carbon to bentonite is (0.1-10):1.

[0018] Preferably, the mass of the adsorbent decolorizing agent is 1-5% of the mass of the deacidified oil.

[0019] Preferably, the decolorization temperature is 80–120°C and the time is 15–40 min.

[0020] Preferably, the deodorization includes: evacuating the decolorized oil, heating the decolorized oil to 100-150°C, introducing nitrogen gas, and maintaining the temperature at 220-300°C.

[0021] The present invention provides a camellia seed compound oil prepared by the preparation method described above, wherein the content of squalene is 145-165 mg / kg; the content of total sterols is 4100-4300 mg / kg; the content of polyphenols is 15-40 mg / kg; and the content of vitamin E is 155-210 mg / kg.

[0022] This invention provides a method for preparing camellia seed compound oil, comprising the following steps: mixing crude camellia seed oil with an acidic solution for a first degumming reaction to obtain degummed oil; mixing the degummed oil with an alkaline solution for a second deacidification reaction to obtain deacidified oil; mixing the deacidified oil with an adsorbent and decolorizing agent for a third decolorization to obtain decolorized oil; introducing nitrogen gas into the decolorized oil and deodorizing it under vacuum conditions to obtain refined oil; and mixing the degummed oil with the refined oil for a fourth mixture to obtain camellia seed compound oil; wherein, during the fourth mixture, the mass of the degummed oil is 10-70% of the total mass of the refined oil and the degummed oil. Because camellia seed degummed oil has the strongest oxidative stability and contains a high content of active ingredients, this invention, by compounding camellia seed degummed oil with camellia seed refined oil, can improve the oxidative stability and active ingredient content of the camellia seed refined oil.

[0023] Furthermore, the crude camellia seed oil of this invention is obtained by pressing camellia seeds; the camellia seeds are refrigerated and stored at a temperature of 2–8°C. By refrigerating the oil, this invention can further increase the content of active ingredients in the compound camellia seed oil. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The image shows a product of a blend of camellia seed oil containing different proportions of degummed oil. Detailed Implementation

[0026] This invention provides a method for preparing a compound oil from camellia seeds, comprising the following steps:

[0027] The crude oil from camellia seeds is first mixed with an acidic solution to carry out a degumming reaction, resulting in degummed oil.

[0028] The degummed oil is mixed with an alkaline solution to carry out a deacidification reaction, thereby obtaining deacidified oil;

[0029] The deacidified oil is mixed with the third adsorption and decolorizing agent for decolorization to obtain decolorized oil;

[0030] Nitrogen gas is introduced into the decolorized oil, and deodorization is carried out under vacuum conditions to obtain refined oil.

[0031] The degummed oil is mixed with the refined oil to obtain camellia seed compound oil;

[0032] In the fourth mixing, the mass of the degumming oil is 10-70% of the total mass of the refined oil and the degumming oil.

[0033] This invention involves mixing crude camellia seed oil with an acidic solution to carry out a degumming reaction, thereby obtaining degummed oil.

[0034] In this invention, the crude camellia seed oil is preferably obtained by pressing camellia seeds; the pressing temperature is preferably 120°C; and the camellia seeds are preferably refrigerated and stored at a temperature of 2–8°C. By using refrigeration, this invention can further increase the content of active ingredients in the compound camellia seed oil.

[0035] This invention involves mixing crude camellia seed oil with an acidic solution to carry out a degumming reaction, thereby obtaining degummed oil.

[0036] In this invention, the acidic solution is preferably a phosphoric acid solution or a citric acid solution; the mass concentration of the phosphoric acid solution is preferably 65-85%, more preferably 70-80%; the mass concentration of the citric acid solution is preferably 30-50%, more preferably 35-45%; the mass of the acidic solution is preferably 0.1-0.5% of the mass of the crude camellia seed oil, more preferably 0.2-0.4%. In this invention, the temperature of the first mixing is preferably 50°C; the first mixing preferably includes: heating the crude camellia seed oil to the mixing temperature, and then adding the acidic solution under stirring. In this invention, the temperature of the degumming reaction is preferably 50-90°C, more preferably 60-85°C, more preferably 65-80°C; the time of the degumming reaction is preferably 10-50 min, more preferably 15-45 min, more preferably 20-35 min. This invention does not have any particular requirements for the heating method; a heating method well known in the art can be used.

[0037] After the degumming reaction is completed, the present invention preferably mixes the obtained oil sample with water and stirs it, then sequentially performs heat preservation and static sedimentation, and then separates the degummed oil. In the present invention, the water is preferably deionized water; the water temperature is preferably 80°C; the water mass is preferably 0.2% of the oil sample mass; the stirring time is preferably 15 min; the heat preservation temperature is preferably 80°C, and the time is preferably 80 min. In the present invention, mixing the obtained oil sample with water can remove the hydrophilic phospholipids in the oil sample, and the heat preservation and static sedimentation allows the hydrophilic phospholipids to precipitate at the bottom, facilitating separation. The present invention does not have special requirements for the separation method, and methods well known in the art can be used.

[0038] In this invention, the colloidal dispersion phase of crude camellia seed oil, in addition to hydrophilic phospholipids, also contains a portion of non-hydrophilic phospholipids (β-phospholipids, calcium magnesium double salt phospholipids, N-acylphosphatidylcholine, and lysophospholipids), as well as complex complexes of protein degradation products (peptones). Some of these substances are non-hydrophilic due to the symmetry of their structure, while others, due to hydration, are easily surrounded by a water film on the particle surface (water-encapsulated molecules), increasing their electrorepulsion. Therefore, they are not easily aggregated during hydration degumming. For this type of colloidal dispersion phase, based on the principle of colloid hydration and aggregation, an acidic solution is added to neutralize the surface charge of the colloidal dispersion particles, eliminating (or reducing) the electron potential or hydration degree of the particles, thus promoting the aggregation of the colloidal particles; and promoting the transformation of calcium magnesium double salt phospholipids, N-acylphosphatidylcholine, and symmetrical (β-) phospholipids into hydrophilic phospholipids. After the addition of water, the hydrophilic phospholipids can bind with water and be removed through separation, thereby improving the oxidative stability of camellia seed oil.

[0039] After obtaining the degummed oil, the present invention mixes the degummed oil with an alkaline solution for a second deacidification reaction to obtain deacidified oil.

[0040] In this invention, the alkaline solution is preferably a sodium hydroxide solution or a potassium hydroxide solution; the mass concentration of the alkaline solution is preferably 6-14%, more preferably 8-12%. In this invention, the acid value of the degumming oil is first determined, and the amount of alkali added is calculated according to the following formula:

[0041] Theoretical alkali content (g) = 7.13 × 10 -4 × weight of degummed oil (g) × acid value (mg / g), the excess alkali amount (g) is taken as 0.2% of the weight of degummed oil (g);

[0042] Actual total alkali content (g) = (theoretical alkali content + excess alkali content) / mass fraction of alkali solution.

[0043] In this invention, the preferred temperature for the second mixing is 80°C; the second mixing preferably includes: heating the degummed oil to the mixing temperature, and then adding an alkaline solution while stirring. In this invention, the preferred temperature for the deacidification reaction is 50–90°C, more preferably 60–85°C, and even more preferably 65–80°C; the preferred time for the deacidification reaction is 10–50 min, more preferably 20–40 min. In this invention, the deacidification reaction is preferably carried out under stirring conditions, and preferably, the stirring speed is reduced in the last 12 min to allow the soapberry to flocculate. This invention does not have a particular requirement for reducing the stirring speed; a slight rotation of the oil sample is sufficient to avoid affecting soapberry flocculation. In this invention, during the deacidification process, the free fatty acids in the degummed oil react with the alkaline solution to generate sodium fatty acid, i.e., soapberry. This invention does not have a particular requirement for the heating method; any heating method well known in the art can be used.

[0044] After the flocculation is completed, the present invention preferably places the obtained flocculent material for cooling and then separates it to obtain the deacidified oil. The present invention does not have any particular requirements for the separation method; any method well known in the art can be used.

[0045] After obtaining the deacidified oil, the present invention mixes the deacidified oil with the third adsorption decolorizing agent for decolorization to obtain decolorized oil.

[0046] In this invention, the adsorption decolorizing agent is preferably a mixture of activated carbon and activated clay, or a mixture of activated carbon and bentonite; the mass of the adsorption decolorizing agent is preferably 1-5% of the mass of the deacidified oil, more preferably 2-4%; the mass ratio of activated carbon to activated clay is 1:(6-20), more preferably 1:(8-15); the mass ratio of activated carbon to bentonite is (0.1-10):1, more preferably (1-5):1.

[0047] In this invention, the third mixing preferably includes: heating the deacidified oil to a decolorizing temperature, and then adding an adsorbent decolorizing agent thereto. In this invention, the decolorizing temperature is preferably 80–120°C, more preferably 90–110°C; the decolorizing time is preferably 15–40 min, more preferably 20–35 min. In this invention, the decolorization is preferably carried out under stirring conditions. This invention does not have any particular requirements for the heating method; any heating method well known in the art can be used.

[0048] After the decolorization is completed, the present invention preferably separates the obtained oil sample to obtain the decolorized oil. The present invention does not have particular requirements for the separation method; any method well-known in the art can be used.

[0049] After obtaining the decolorized oil, the present invention introduces nitrogen gas into the decolorized oil and deodorizes it under vacuum conditions to obtain refined oil.

[0050] In this invention, the deodorization preferably includes: evacuating the decolorized oil under vacuum, heating the decolorized oil to 100-150°C, more preferably to 120-135°C, then introducing nitrogen gas, raising the temperature to 220-300°C and holding it thereafter, more preferably raising the temperature to 250-280°C and holding it thereafter. In this invention, the holding time is preferably 2 hours; the deodorization is preferably carried out under stirring conditions. This invention, under the action of nitrogen gas and vacuum, can extract some substances that cause odor in oils, such as low-molecular-weight fatty acids, hydrocarbons, aldehydes, and peroxides, and can also remove the odor from the adsorbent decolorizing agent added during the decolorization process.

[0051] After obtaining the refined oil, the present invention mixes the degummed oil with the refined oil in a fourth step to obtain camellia seed compound oil.

[0052] In this invention, the fourth mixing is preferably carried out under stirring conditions; the stirring speed and time are not required, as long as a uniform color of camellia seed compound oil is obtained. In this invention, the mass of the degummed oil is 10-70% of the total mass of the refined oil and the degummed oil, preferably 20-60%, and more preferably 30-50%.

[0053] This invention provides a compound camellia seed oil prepared by the method described above, containing squalene at a content of 145–165 mg / kg, total sterols at a content of 4100–4300 mg / kg, polyphenols at a content of 15–40 mg / kg, and vitamin E at a content of 155–210 mg / kg. This invention, by compounding degummed camellia seed oil with refined camellia seed oil, can improve the oxidative stability and active ingredient content of the refined camellia seed oil.

[0054] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, describes the camellia seed compound oil and its preparation method provided by the present invention, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0055] Example 1

[0056] Camellia seeds are pressed at 120℃ to extract crude camellia seed oil.

[0057] Crude camellia seed oil was placed in a degumming tank and heated to 50°C while stirring. Then, 85% phosphoric acid solution (0.2% of the oil weight) was added to the tank, and the mixture was stirred further and heated to 80°C. After reacting for 20 minutes, deionized water (2% of the oil weight) at the same temperature as the oil sample was added, and the mixture was stirred for 15 minutes. The mixture was kept at the temperature and allowed to stand for 80 minutes to settle. The precipitate was then separated to obtain the degummed oil.

[0058] The degummed oil was placed in a deacidification tank, heated to 80°C while stirring, and then 10% NaOH solution was added to the deacidification tank according to the actual amount of alkali to be added (first, the acid value of the degummed oil was determined, and the amount of alkali to be added was calculated according to the following formula: theoretical alkali amount (g) = 7.13 × 10⁻⁶). -4 × weight of degummed oil (g) × acid value (mg / g), excess alkali (g) is taken as 0.2% of the weight of degummed oil (g); actual total alkali (g) = (theoretical alkali + excess alkali) / mass fraction of alkali solution), maintain the temperature and continue stirring for 30 min, reduce the speed in the last 12 min to allow soap flocculation, wait for soap flocculation, let it cool, and then separate the precipitate to obtain deacidified oil;

[0059] The deacidified oil was placed in a decolorizing tank and heated to 93°C. At the same time, 2% of the oil weight of the adsorption decolorizing agent (the ratio of activated carbon to activated clay was 1:10) was added. The mixture was stirred thoroughly for 30 minutes. After the reaction was completed, the precipitate was separated to obtain the decolorized oil.

[0060] The decolorized oil and zeolite were placed in a deodorization tank, and the mixture was stirred under vacuum while condenser was introduced to preheat the oil to 120–135°C. Nitrogen gas was then introduced, and the flow rate was adjusted (maximizing the flow rate without causing violent splashing of the oil sample). The oil was then heated to 220°C and held for 2 hours. After deodorization, the oil temperature was lowered to 70°C under vacuum and nitrogen purging conditions. The vacuum was then released to obtain refined oil.

[0061] The degummed oil is weighed into a container at a ratio of 10% of the total mass of refined oil and degummed oil, and stirred thoroughly for 15 minutes to obtain camellia seed compound oil.

[0062] Example 2

[0063] The preparation steps are the same as in Example 1, except that the degummed oil is weighed in the tank at a ratio of 20% of the total mass of refined oil and degummed oil.

[0064] Example 3

[0065] The preparation steps are the same as in Example 1, except that the degummed oil is weighed in the tank at a ratio of 30% of the total mass of refined oil and degummed oil.

[0066] Example 4

[0067] The preparation steps are the same as in Example 1, except that the degummed oil is weighed in the tank at a ratio of 40% of the total mass of refined oil and degummed oil.

[0068] Example 5

[0069] The preparation steps are the same as in Example 1, except that the degummed oil is weighed in the tank at a ratio of 50% of the total mass of refined oil and degummed oil.

[0070] Example 6

[0071] The preparation steps are the same as in Example 1, except that the degummed oil is weighed in the tank at a ratio of 60% of the total mass of refined oil and degummed oil.

[0072] Example 7

[0073] The preparation steps are the same as in Example 1, except that the degummed oil is weighed in the tank at a ratio of 70% of the total mass of refined oil and degummed oil.

[0074] Performance testing

[0075] (1) The camellia seeds were divided into mesh bags and stored under refrigeration (4°C). The camellia seeds were sampled once a month. The camellia seeds stored at room temperature and under refrigeration were pressed to extract oil. The crude camellia seed oil obtained by pressing was filtered and placed in the refrigerator for testing.

[0076] Table 1. Effects of storage temperature on crude oil acid value and peroxide value of camellia seeds.

[0077]

[0078] Note: The numerical values ​​of different letters in the same row in Tables 1-10 indicate significant differences (p<0.05).

[0079] Acid value refers to the content of free fatty acids produced by the hydrolysis of triglycerides in oils and fats, and it is an important indicator reflecting the quality of oils and fats. The acid value of oil in camellia seeds stored at different temperatures was determined by titration. Table 1 shows that the acid value of oil in camellia seeds before storage and after one month of storage at room temperature was relatively high, at 0.36 mg / g. After five months of storage at room temperature, the acid value had risen to 0.39 mg / g, while the acid value of oil in camellia seeds under refrigerated conditions was lower and more stable, at 0.31 mg / g.

[0080] Table 2. Effects of storage temperature on the content of sterols, squalene, polyphenols, and vitamin E in crude camellia seed oil (0–2 months)

[0081]

[0082]

[0083] Table 3. Effects of storage temperature on the content of sterols, squalene, polyphenols, and vitamin E in crude camellia seed oil (3–5 months)

[0084]

[0085] Squalene is a polyunsaturated triterpenoid compound with physiological functions such as anti-aging, immune enhancement, cancer prevention, and lowering serum cholesterol, and is therefore widely used in the pharmaceutical, food, and cosmetic fields. Sterols in crude camellia seed oil are phytosterols, whose physiological functions and structures are similar to cholesterol in animal bodies, possessing anti-inflammatory, anti-cancer, cholesterol-lowering, and cardiovascular disease-preventing effects. Therefore, the content of squalene and sterols are important quality indicators of crude camellia seed oil.

[0086] This invention uses GC-MS to determine the squalene and sterol content of oil in camellia seeds stored at different temperatures. Tables 2-3 show that after two months of storage, the squalene content of oil in cold-stored camellia seeds was significantly higher than that in seeds stored at room temperature. This is likely because low temperature inhibits squalene oxidation. During subsequent storage periods, there was no significant difference in squalene content of oil in camellia seeds stored at both temperatures, and the squalene content gradually decreased with prolonged storage time in both cold-stored and room-temperature stored seeds. After five months of storage, the squalene content of oil in cold-stored and room-temperature stored camellia seeds decreased from the initial 212.05 mg / kg to 115.47 mg / kg and 107.07 mg / kg, respectively. This is likely because the camellia seeds come into contact with oxygen during storage, leading to the oxidation of squalene to squalene monohydroperoxide, then to squalene 5-hydroperoxide, and finally to squalene epoxide.

[0087] Seven sterols were detected by GC-MS: betulin, stigmasterol, β-amyrin, Germanol, sitosterol, lanosterol, and α-amyrin. Tables 2-3 show that after one month of storage, the sitosterol content in the oil of camellia seeds stored under refrigeration was significantly higher than that stored at room temperature. This is likely because low temperature inhibits sitosterol oxidation. The contents of other sterols did not differ significantly at different storage temperatures, and all showed a gradual decreasing trend with prolonged storage time. This may be because sterols can undergo auto-oxidation with prolonged storage time. Typical oxidation products include 7-hydroxyl, 7-keto, 5,6-epoxy, and 3,5,6-triol derivatives of sterols. These oxidation products may lead to adverse symptoms such as atherosclerosis and inflammation. Oxidized sterols also lose their ability to inhibit cholesterol absorption.

[0088] Polyphenols are secondary metabolites that can slow down the oxidation rate by scavenging free radicals and enhancing the activity of antioxidant enzymes. They also have anti-inflammatory, anti-tumor, and cardiovascular regulatory effects, making them an important active ingredient in crude camellia seed oil. This invention uses a UV spectrophotometer to determine the polyphenol content of camellia seed oil stored at different temperatures. Tables 2-3 show that the polyphenol content gradually decreases with prolonged storage. This may be because polyphenols are oxidized and consumed during the metabolism of camellia seeds. In the first and second months of storage, the polyphenol content of camellia seed oil stored under refrigeration conditions was significantly higher than that stored at room temperature, possibly because low temperature inhibits the rate of oxidation. Afterward, there was no significant difference in the polyphenol content of camellia seed oil stored at the two different temperatures.

[0089] Vitamin E is a class of phenolic compounds with a cromoglycan ring and a 16-carbon side chain. It can donate hydrogen atoms to lipid free radicals to prevent lipid oxidation and also has anti-inflammatory, anti-tumor, and cardiovascular disease prevention effects. This invention uses high-performance liquid chromatography (HPLC) to determine the vitamin E content in camellia seed oil at different storage temperatures. Tables 2-3 show that the vitamin E content gradually decreases with prolonged storage time. In the first two months of storage, the vitamin E content in camellia seed oil is relatively stable at different storage temperatures. In the third month, the vitamin E content begins to decrease slightly. By the fifth month, the vitamin E content in camellia seed oil under refrigerated and room temperature conditions had decreased to 302.75 mg / kg and 302.79 mg / kg, respectively, significantly lower than the vitamin E content in camellia seed oil during the early storage period. This may be due to the high content of unsaturated fatty acids in camellia seed oil. Unsaturated fatty acids produce lipid hydroperoxides through free radical chain reactions. Vitamin E slows down the oxidation rate by contributing hydrogen atoms from its hydroxyl groups to the peroxide free radicals generated during lipid oxidation, leading to a decrease in the vitamin E content of camellia seed oil. However, there was no significant difference in vitamin E content in camellia seed oil under refrigerated and room temperature conditions across different storage months. Therefore, to preserve the vitamin E content of camellia seed oil, it should be processed as soon as possible after harvesting to prevent oxidative loss of vitamin E.

[0090] Table 4. Effects of storage temperature on fatty acid composition of crude camellia seed oil

[0091]

[0092] Fatty acids can be classified into saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids, playing various roles in the human body. For example, saturated fatty acid intake increases cholesterol levels, while unsaturated fatty acids have anti-atherosclerotic and anti-thrombotic effects. This invention uses GC-MS to determine the fatty acid composition of oil in camellia seeds at different storage temperatures. Table 4 shows that five fatty acids were detected in crude camellia seed oil: palmitic acid, stearic acid, oleic acid, linoleic acid, and trans-linoleic acid. Unsaturated fatty acids accounted for approximately 88%, with oleic acid being the main unsaturated fatty acid, accounting for over 75%. With prolonged storage, the linoleic acid content in camellia seed oil gradually decreased. After two months of storage, the linoleic acid content in camellia seed oil stored under refrigeration conditions was significantly higher than that stored at room temperature. This may be because during lipid oxidative rancidity, the oxidation reaction mainly occurs at the unsaturated double bonds of unsaturated fatty acids, and the oxidation rate of linoleic acid is approximately 10 times that of oleic acid. Therefore, the linoleic acid content in camellia seed oil decreased significantly during storage.

[0093] In summary, storage temperature significantly affects the acid value, peroxide value, polyphenols, squalene, sterols, and fatty acid composition of camellia seeds during storage. Camellia seeds stored at low temperatures exhibit lower acid values ​​and peroxide values. Furthermore, in the early stages of storage, the contents of polyphenols, squalene, sitosterol, and linoleic acid in camellia seeds under refrigerated conditions are higher than at room temperature. Analysis suggests that low temperatures can, to some extent, slow down the oxidation rate of camellia seeds during storage and preserve the content of active ingredients.

[0094] (2) The crude oil of camellia seeds was refined to obtain degummed, deacidified, decolorized and deodorized oil, and its oxidation induction time and active ingredient content were determined. The degummed oil was mixed with the refined oil to obtain camellia seed compound oil, which was then placed in a refrigerator for testing.

[0095] Table 5 Oxidation induction time at each stage of camellia seed oil refining

[0096]

[0097] The oxidation induction time of oils is an indicator used to accelerate oxidation at high temperatures and rapidly determine the oxidative stability of oils. The longer the oxidation induction time, the better the oxidative stability of the oil. The oxidation induction time of camellia seed oil with different degrees of refining was measured using an oil oxidation analyzer. As shown in Table 5, the oxidation induction time of crude camellia seed oil increased significantly after degumming treatment, from 19.54 h to 30.29 h.

[0098] Table 6. Fatty acid composition of crude camellia seed oil, degummed oil, and refined oil.

[0099] Fatty acid percentage / % Palmitic acid stearic acid Oleic acid Linoleic acid trans-linoleic acid Crude camellia seed oil <![CDATA[10.12±0.08 a ]]> <![CDATA[1.92±0.00 a ]]> <![CDATA[76.34±0.04 b ]]> <![CDATA[9.86±0.04 a ]]> <![CDATA[1.76±0.00 a ]]> Degumming oil <![CDATA[9.94±0.14 a ]]> <![CDATA[1.78±0.00 b ]]> <![CDATA[77.77±0.20 a ]]> <![CDATA[8.97±0.02 b ]]> <![CDATA[1.54±0.05 b ]]> Refined oil <![CDATA[9.95±0.03 a ]]> <![CDATA[1.93±0.02 a ]]> <![CDATA[76.78±0.04 b ]]> <![CDATA[9.56±0.14 a ]]> <![CDATA[1.78±0.05 a ]]>

[0100] The fatty acid composition of crude camellia seed oil, degummed oil, and refined oil was determined by GC-MS. Table 6 shows that the fatty acid composition of crude camellia seed oil, degummed oil, and refined oil is consistent, consisting of palmitic acid, stearic acid, oleic acid, linoleic acid, and trans-linoleic acid, with oleic acid being the predominant component, accounting for approximately 77%. The overall fatty acid composition of crude camellia seed oil, degummed oil, and refined oil shows little difference.

[0101] Table 7. Sterol, squalene, polyphenol, and vitamin E content of crude camellia seed oil, degummed oil, and refined oil.

[0102] Active ingredient / mg / kg Crude camellia seed oil Degumming oil Refined oil Squalene <![CDATA[212.05±0.79 a ]]> <![CDATA[167.88±5.89 b ]]> <![CDATA[146.34±1.07 c ]]> betulin <![CDATA[96.91±4.45 a ]]> <![CDATA[84.44±0.49 a ]]> <![CDATA[104.38±9.07 a ]]> Stigmasterol <![CDATA[708.31±36.85 a ]]> <![CDATA[547.90±7.94 b ]]> <![CDATA[394.34±39.75 c ]]> β-amyrin alcohol <![CDATA[2203.68±78.93 a ]]> <![CDATA[1895.33±135.76 a ]]> <![CDATA[1783.87±29.59 a ]]> Germanic alcohol <![CDATA[170.35±10.85 a ]]> <![CDATA[178.60±35.11 a ]]> <![CDATA[132.53±4.65 a ]]> sitosterol <![CDATA[765.97±11.53 a ]]> <![CDATA[545.52±16.42 a ]]> <![CDATA[490.31±17.19 a ]]> Lanosterol <![CDATA[1239.42±6.76 a ]]> <![CDATA[988.90±38.57 a ]]> <![CDATA[1012.00±21.93 a <!-- 9 -->]]> α-Ambrosial alcohol <![CDATA[194.05±1.46 a ]]> <![CDATA[146.17±5.36 a ]]> <![CDATA[157.89±6.98 a ]]> Total sterols <![CDATA[5378.69±52.51 a ]]> <![CDATA[4386.86±102.09 a ]]> <![CDATA[4075.33±69.97 a ]]> Polyphenols <![CDATA[65.66±2.15 a ]]> <![CDATA[43.03±1.02 b ]]> <![CDATA[14.66±1.39 c ]]> Vitamin E <![CDATA[339.76±0.76 a ]]> <![CDATA[228.81±0.61 b ]]> <![CDATA[152.83±2.06 c ]]>

[0103] As shown in Tables 5-7, degumming oil has the strongest oxidative stability and contains a high content of active ingredients.

[0104] Table 8. Effect of compounding ratio on oxidation induction time of camellia seed compound oil.

[0105]

[0106] The oxidation induction time of camellia seed blended oils with different blending ratios was determined using an oil oxidation analyzer. Table 8 shows that when the degummed oil content was 10%, the oxidation induction time of the camellia seed blended oil was 25.24 h, significantly higher than that of refined oil. This may be because degummed oil has a higher content of active ingredients and stronger oxidation stability, thus improving the oxidation stability of the camellia seed blended oil after adding 10% degummed oil. When the degummed oil content was below 40%, the oxidation induction time of the camellia seed blended oil did not change significantly with the increase of the degummed oil content. When the degummed oil content increased to above 40%, the oxidation induction time of the camellia seed blended oil began to increase significantly.

[0107] Table 9. Content of active ingredients in camellia seed blended oils with different blending ratios.

[0108]

[0109]

[0110] Table 9 shows that the content of active substances in the camellia seed compound oil increases with the increase of degummed oil content.

[0111] Figure 1 This is a diagram showing blended oils from camellia seeds containing different proportions of degummed oil. Figure 1 It can be seen that as the proportion of degummed oil increases, the color of the camellia seed blended oil gradually deepens. In actual production, considering the color, oxidation induction time, and active ingredient content of the camellia seed blended oil, different blending ratios can be selected according to the characteristics of different products to obtain camellia seed oil products with the best overall quality.

[0112] (3) The acid value and peroxide value of crude camellia seed oil, degummed oil and refined oil were determined by titration. The results are shown in Table 10.

[0113] Table 10 Acid value and peroxide value of crude camellia seed oil, degummed oil and refined oil

[0114] Crude camellia seed oil Degumming oil Refined oil Acid value / mg / g <![CDATA[0.36±0.00 b ]]> <![CDATA[0.39±0.00 a ]]> <![CDATA[0.06±0.00 c ]]> Peroxide value / mmol / kg <![CDATA[0.30±0.00 b ]]> <![CDATA[0.54±0.00 a ]]> <![CDATA[0.55±0.00 a ]]>

[0115] As shown in Table 10, the acid values ​​of crude camellia seed oil and degummed oil are significantly higher than those of refined oil. This is because the refined oil undergoes deacidification treatment. The peroxide value of crude oil is 0.30 mmol / kg, which is significantly lower than that of degummed oil and refined oil. This may be because the subsequent refining process needs to be carried out under high temperature conditions. The increased oil temperature promotes the oxidation of camellia seed oil, leading to an increase in peroxide value.

[0116] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a compound oil from camellia seeds, characterized in that, Includes the following steps: The crude oil from camellia seeds is first mixed with an acidic solution to carry out a degumming reaction, resulting in degummed oil. The crude camellia seed oil is obtained by pressing camellia seeds; The camellia seeds are refrigerated and stored at a temperature of 2-8℃; The degummed oil is mixed with an alkaline solution to carry out a deacidification reaction, thereby obtaining deacidified oil; The deacidified oil is mixed with the third adsorption and decolorizing agent for decolorization to obtain decolorized oil; Nitrogen gas is introduced into the decolorized oil, and deodorization is carried out under vacuum conditions to obtain refined oil. The degummed oil is mixed with the refined oil to obtain camellia seed compound oil; In the fourth mixing process, the mass of the degumming oil is 10-70% of the total mass of the refined oil and the degumming oil.

2. The preparation method according to claim 1, characterized in that, The acidic solution is a phosphoric acid solution or a citric acid solution; the mass concentration of the phosphoric acid solution is 65-85%; the mass concentration of the citric acid solution is 30-50%; and the mass of the acidic solution is 0.1-0.5% of the mass of crude camellia seed oil.

3. The preparation method according to claim 1 or 2, characterized in that, The degumming reaction is carried out at a temperature of 50-90℃ for 10-50 minutes.

4. The preparation method according to claim 1, characterized in that, The alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution; the mass concentration of the alkaline solution is 6-14%; the temperature of the deacidification reaction is 50-90℃, and the time is 10-50 min.

5. The preparation method according to claim 1, characterized in that, The adsorption and decolorizing agent is a mixture of activated carbon and activated clay, or a mixture of activated carbon and bentonite; the mass ratio of activated carbon to activated clay is 1:(6~20); the mass ratio of activated carbon to bentonite is (0.1~10):

1.

6. The preparation method according to claim 1, characterized in that, The mass of the adsorbent and decolorizing agent is 1-5% of the mass of the deacidified oil.

7. The preparation method according to claim 1 or 6, characterized in that, The decolorization temperature is 80~120℃, and the time is 15~40min.

8. The preparation method according to claim 1, characterized in that, The deodorization process includes: evacuating the decolorized oil under vacuum, heating the decolorized oil to 100-150°C, introducing nitrogen gas, and maintaining the temperature at 220-300°C.

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