Refining method for reducing and controlling plasticizer and 3-chloropropanol ester in camellia oil

Abstract

The invention relates to a refining method for reducing and controlling a plasticizer and 3-chloropropanol ester in camellia oil, and aims to effectively control the plasticizer, the 3-chloropropanol ester and glycidyl ester in the camellia oil and maintain nutritional ingredients and natural flavor of the camellia oil. The method comprises the steps of acidification degumming, alkali refining deacidification, water washing, decoloration, dual-temperature deodorization, low-temperature adsorption and the like, and particularly, the vacuum degree and the temperature are finely adjusted in the deodorization process, so that control over a plasticizer, 3-chloropropanol ester and glycidyl ester is effectively considered.

Description

Technical Field

[0001] This invention relates to the technical field of camellia oil, and in particular to a refining method for reducing and controlling the presence of plasticizers and 3-chloropropanol esters in camellia oil. Background Technology

[0002] Camellia oil, also known as tea seed oil, is a high-quality woody oil unique to my country. It is rich in unsaturated fatty acids, natural vitamin E, and various trace elements, possessing high nutritional and application value. The industrial refining process of camellia oil typically involves key steps such as degumming, deacidification, washing, decolorization, deodorization, and post-treatment. The entire process involves various technological conditions including high temperature, negative pressure, steam stripping, and solid-liquid contact.

[0003] Various hazardous substances exist during the refining process, including plasticizers, especially phthalates. These plasticizers mainly originate from the raw material harvesting and storage process, the production workshop environment, and migration from hoses, seals, tank linings, and packaging materials that come into direct contact with the oils. Besides the risks posed by plasticizer migration, the deodorization stage in the refining process may also generate process byproducts such as 3-chloropropanol esters and glycidyl esters. Under high-temperature steam deodorization conditions, some glycerol ester structures and trace amounts of moisture in the oils participate in side reactions. The formation of 3-chloropropanol esters is closely related to the level of migratable chloride ions in the system.

[0004] Current camellia oil refining processes mostly employ a single-stage, high-temperature, long-duration vacuum deodorization method to meet the process requirements of deodorization and removal of volatile pollutants. While this high-temperature, long-duration treatment method is beneficial for removing volatile / semi-volatile pollutants such as plasticizers that have migrated into the oil phase, the increased deodorization intensity often amplifies the risk of formation of 3-chloropropanol esters and glycidyl esters. Furthermore, it is accompanied by the loss of natural flavor components and some nutritionally active substances, creating a significant process contradiction.

[0005] In summary, how to establish a refining control strategy that is compatible with the removal of migratory pollutants and the inhibition of process products without relying on simply increasing the deodorization temperature and time, and to achieve simultaneous control of plasticizers, 3-chloropropanol esters and glycidyl esters, has become an urgent technical problem to be solved in the field of camellia oil refining. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned problems existing in the prior art and provide a refining method for reducing and controlling plasticizers and 3-chloropropanol esters in camellia oil. By synergistically controlling the deodorization process conditions and post-treatment steps during the refining process, the method effectively inhibits the formation of 3-chloropropanol esters and glycidyl esters during high-temperature refining while ensuring the normal refining, impurity removal and deodorization requirements of camellia oil, and simultaneously reduces the residual level of plasticizers in the oil.

[0007] To achieve the above objectives, the present invention provides a refining method for reducing and controlling the presence of plasticizers and 3-chloropropanol esters in camellia oil, comprising the following steps: S1 Acid Degumming: Camellia crude oil is heated and then acid-treated to remove phospholipids from the camellia oil, resulting in degummed oil; S2 Alkali Refining and Deacidification: Take the degummed oil obtained in step 1, perform alkali refining and deacidification to remove free fatty acids from the camellia oil, and obtain deacidified oil after centrifugation and soap removal. S3 Wash: The desoaped camellia oil is washed with purified water at the same temperature until it is neutral, and then vacuum dried to remove the water from the camellia oil. S4 Decolorization: The dried camellia oil is fed into the decolorization tower for decolorization. After decolorization, the camellia oil enters the gas separator to remove air and moisture from the oil. S5 dual temperature deodorization: First deodorization stage: The camellia oil after gas separation is heated to 180-200℃ and then pumped into the deodorization tower for 40-50 minutes; Second deodorization stage: The camellia oil is heated to 250~260℃ and fed into a packed tower for secondary deodorization. The deodorization time in the packed tower is 10~20 minutes to obtain deodorized oil. S6 Low-Temperature Adsorption: Filter aid and activated carbon are added to the deodorized oil to induce winterization and crystallization. After crystallization, the oil is filtered to obtain the finished product.

[0008] Preferably, the first deodorization stage uses a vacuum degree of 0.05~0.1MPa, and the second deodorization stage uses a vacuum degree of 0.02~0.05MPa.

[0009] Preferably, the vacuum degree of both the first deodorization stage and the second deodorization stage is adjusted gradually; in the first deodorization stage, the initial vacuum degree is 0.05~0.08MPa and is maintained for 20~25min, then the vacuum degree is adjusted to 0.08~0.1MPa and maintained for 15~25min; in the second deodorization stage, the initial vacuum degree is 0.02~0.03MPa and is maintained for 5~10min, then the vacuum degree is adjusted to 0.03~0.05MPa and maintained for 5~10min.

[0010] Preferably, the temperature control of the first deodorization stage and the second deodorization stage adopts segmented temperature regulation control; the initial temperature of the first deodorization stage is set to 180°C, and the temperature is raised to 185°C to 190°C within 10 to 15 minutes, then maintained at this temperature for 20 to 25 minutes, and finally raised to 195°C to 200°C and maintained for 5 to 10 minutes; the initial temperature of the second deodorization stage is set to 250°C, and the temperature is raised to 255°C to 260°C within 10 to 15 minutes, then maintained at this temperature for 5 to 10 minutes.

[0011] By setting up a medium-temperature stripping stage in the first deodorization stage and a short-range high-temperature fine stripping stage in the second deodorization stage, combined with gradual vacuum regulation, the accumulation of side reactions caused by single-stage high-temperature long-term deodorization is reduced, while providing sufficient mass transfer driving force for the volatilization and removal of migrating plasticizers. In the first deodorization stage, a medium-temperature window of 180-200℃ is used, combined with gradual vacuum regulation, so that low-boiling-point odor components and some semi-volatile plasticizers are preferentially carried out; this stage avoids prolonged residence at the highest temperature, thereby reducing the thermal formation of 3-chloropropanol esters and glycidyl esters.

[0012] In the second deodorization stage, a short-pass treatment of 10–20 min at a higher temperature of 250–260°C is performed, and the removal of difficult-to-remove components is completed under a deeper vacuum. Compared with traditional single-stage high-temperature long-time deodorization, this short-time high-temperature strategy reduces the cumulative time for precursor structures such as diacylglycerols to participate in side reactions at high temperatures. At the same time, the S3 water wash uses low-chloride-ion purified water and controls residual moisture through vacuum drying, which reduces the levels of migratable chloride ions and moisture in the deodorization system, weakening the conditions for 3-chloropropanol ester formation from the source. The low-temperature adsorption step after deodorization introduces a combined filtration system of diatomaceous earth and activated carbon under crystallization conditions of 2–4°C, removing trace amounts of pigments, polar impurities, and residual plasticizers without introducing additional high-temperature loads, and further reducing any possible residual reaction precursors. Together with the dual-temperature deodorization, this forms a closed-loop control of high-temperature removal and low-temperature purification, thereby reducing plasticizer residues while inhibiting 3-chloropropanol esters and glycidyl esters, and maintaining flavor and nutrition.

[0013] Preferably, in the S1 acidification and degumming stage, citric acid is used, with a mass concentration of 35%~40%, the amount of acid added is 0.2~0.5% of the mass of camellia oil, the acid treatment time is 10~15 min, and the treatment temperature is 40℃~50℃.

[0014] Preferably, in the S2 alkali refining and deacidification stage, the concentration of the alkali solution used is 20~25°Bé, the alkali refining temperature is 65~70℃, and the deacidification time is 15~20min.

[0015] Preferably, the water content in the camellia oil after vacuum drying in the S3 water washing stage does not exceed 0.1% by mass.

[0016] Preferably, in the S4 decolorization stage, the decolorizing agent used is activated clay, the amount of which is added is 1.5% to 2.5% of the weight of camellia oil, the decolorization temperature is controlled at 110℃ to 120℃, and the decolorization time is 30 to 50 minutes.

[0017] Preferably, in the S6 low-temperature adsorption stage, the filter aid used is diatomaceous earth, and the amount added is 1% to 2% of the weight of the deodorized oil. The amount of activated carbon added is 3% to 4% of the weight of the deodorized oil, and crystallization is carried out at a crystallization temperature of 2 to 4°C for 18 to 24 hours.

[0018] The present invention, by adopting the above technical solution, has the following beneficial effects: This invention achieves precise control of vacuum and temperature in the first and second deodorization stages during the deodorization process, effectively controlling plasticizers, 3-chloropropanol esters, and glycidyl esters in camellia oil to resolve the conflict between plasticizer removal and 3-chloropropanol ester / glycidyl ester inhibition. Specifically, the temperature and vacuum levels in the first deodorization stage are adjusted gradually to avoid loss of flavor and nutrients due to excessive removal of volatile substances. In the first stage, lighter volatile substances are removed initially at a lower vacuum level, and then the vacuum level is gradually increased, effectively preventing over-deodorization while ensuring sufficient removal of plasticizers and reducing the formation of harmful substances such as 3-chloropropanol esters and glycidyl esters. Furthermore, the first deodorization stage employs a segmented heating strategy. The initial temperature is 180℃, gradually increasing to 185℃-190℃ within 10-15 minutes, then maintaining this temperature for 20-25 minutes. Finally, the temperature is raised to 195℃-200℃ and maintained for 5-10 minutes. This process ensures the removal of volatile substances within a suitable temperature range while minimizing the damage to the oil's nutritional components and flavor caused by excessively high temperatures, thus effectively guaranteeing the oil's quality stability and preventing damage to the inherent properties of camellia oil at high temperatures. In the second deodorization stage, the temperature starts at 250℃ and gradually increases to 255℃-260℃ within 10-15 minutes, maintaining this temperature for 5-10 minutes. This ensures the removal of more difficult-to-remove volatile components from the camellia oil while avoiding prolonged exposure to high temperatures. Temperature control in this stage ensures efficient deodorization without excessively affecting other components of the camellia oil. Vacuum control still employs a gradual adjustment, ensuring that non-volatile harmful substances in the oil can be fully removed at lower temperatures, thus guaranteeing a highly efficient and gentle deodorization effect.

[0019] In addition to the deodorization process, each refining step also ensures the effective removal of harmful components such as plasticizers, 3-chloropropanol esters, and glycidyl esters, while preserving the nutritional components and natural flavor of camellia oil to the greatest extent.

[0020] In the acidification and degumming stage, citric acid was used for treatment, and the acid concentration, amount added, treatment time, and temperature were controlled to ensure the effective removal of phospholipids and other impurities from the camellia oil. This avoided negative impacts on oil quality due to overtreatment and reduced interference from other impurities in subsequent refining processes, providing a purer oil for the subsequent deacidification and decolorization stages. In the alkali refining and deacidification stage, the concentration of alkali and the treatment temperature were controlled to efficiently remove free fatty acids from the camellia oil. Strict control of the alkali refining temperature and deacidification time not only ensured the removal rate of fatty acids but also prevented excessive reaction of the alkali to the oil, effectively improving the deacidification effect, further purifying the oil, and avoiding unnecessary impacts on subsequent decolorization and deodorization stages. In the water washing step, the addition of purified water at the same temperature and vacuum drying ensured the thorough removal of moisture from the camellia oil, and the water washing process did not cause any adverse effects on the oil's flavor. Furthermore, the chloride ion content of the purified water did not exceed 5 mg / L, which greatly reduced the introduction of chloride ions. The moisture content of the washed camellia oil was strictly controlled to no more than 0.1%, which laid the foundation for the subsequent decolorization and low-temperature adsorption steps. This avoided interference from moisture in the oil during the decolorization and adsorption processes, improving refining efficiency and effectiveness. In the decolorization stage, activated clay was used as the decolorizing agent, and decolorization was carried out at a controlled temperature. This effectively removed pigments and other pigment impurities from the camellia oil, ensuring the oil's clarity and transparency while avoiding damage to the oil's flavor from excessive decolorization. In the low-temperature adsorption stage, diatomaceous earth and activated carbon were used in combination as filter aids to ensure the thorough removal of any trace impurities and moisture that might remain in the camellia oil. The use of diatomaceous earth not only provided excellent filtration but also enhanced the oil's clarity, while activated carbon effectively adsorbed any impurities, further purifying the camellia oil. Detailed Implementation

[0021] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0022] Unless otherwise defined, all scientific and technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art.

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0025] The present invention will now be described in detail with reference to specific embodiments, which are intended to understand rather than limit the invention.

[0026] Example 1 This embodiment discloses a refining method for reducing and controlling the presence of plasticizers and 3-chloropropanol esters in camellia oil, comprising the following steps: S1 Acidification and Degumming: Camellia crude oil was heated to 45°C, and food-grade citric acid with a mass concentration of 40% was added for acid treatment at a concentration of 0.3% of the oil weight. The acid treatment time was 10 minutes. In this example, the camellia crude oil had a moisture content of 0.13%, an acid value of 3.21 mg / g, a peroxide value of 0.06 g / 100g, a DBP content of 1.19 mg / kg, a DEHP content of 1.86 mg / kg, and DINP was not detected.

[0027] S2 Alkali Refining and Deacidification: Stir the deacidified oil and heat it to 65°C. Add an alkali solution with a concentration of 25°Bé according to the acid value of camellia oil to carry out a neutralization reaction. The reaction time is 20 minutes. Centrifuge to remove the soap pods generated in the reaction.

[0028] Acid value refers to the content of free fatty acids in camellia oil, and the required amount of alkali solution is calculated using the following formula (1).

[0029] (1) S3 Wash: After desoaping, the camellia oil is washed with purified water at the same temperature at 5% of its weight until it becomes neutral. Then, it is vacuum dried to remove the water from the camellia oil, with the water content not exceeding 0.1% by mass.

[0030] S4 Decolorization: The centrifuged camellia oil is fed into a decolorization tower for decolorization. The amount of activated clay added is 2.5% of the weight of the camellia oil. The decolorization temperature is 120℃ and the decolorization time is 40 minutes to remove the color of the camellia oil. After decolorization, the oil enters the gas separator to remove air and moisture from the oil.

[0031] S5 dual temperature deodorization: First deodorization stage: The oil after gas separation is heated to 190℃ and then pumped into the deodorization tower. The deodorization time is 50 minutes and the vacuum degree is 0.1MPa. Second deodorization stage: The oil is heated to 260℃ and fed into a packed tower for secondary deodorization. The deodorization time in the packed tower is 15 minutes and the vacuum degree is 0.05MPa to obtain deodorized oil.

[0032] S6 Winterization Dewaxing: Add 1% filter aid (diatomaceous earth) and 3.5% activated carbon to the deodorized oil for winterization crystallization at a temperature of 4℃. After reaching the temperature, crystallize for 24 hours, then filter, polish, and obtain the finished oil.

[0033] Example 2 This embodiment discloses a refining method for reducing and controlling the presence of plasticizers and 3-chloropropanol esters in camellia oil, comprising the following steps: S1 Acid Degumming: Heat the camellia oil to 45℃, add 40% food-grade citric acid for acid treatment, the amount added is 0.3% of the oil weight, and the acid treatment time is 10 minutes.

[0034] S2 Alkali Refining and Deacidification: Stir the deacidified oil and heat it to 65°C. Add an alkali solution with a concentration of 25°Bé according to the acid value of camellia oil to carry out a neutralization reaction. The reaction time is 20 minutes. Centrifuge to remove the soap pods generated in the reaction.

[0035] S3 Wash: After desoaping, the camellia oil is washed with purified water at the same temperature at 5% of its weight until it becomes neutral. Then, it is vacuum dried to remove the water from the camellia oil, with the water content not exceeding 0.1% by mass.

[0036] S4 Decolorization: The centrifuged camellia oil is fed into a decolorization tower for decolorization. The amount of activated clay added is 2.5% of the weight of the camellia oil. The decolorization temperature is 120℃ and the decolorization time is 40 minutes to remove the color of the camellia oil. After decolorization, the oil enters the gas separator to remove air and moisture from the oil.

[0037] S5 dual temperature deodorization: First deodorization stage: The oil after gas evolution is heated to 200℃ and then pumped into the deodorization tower. The deodorization time is 40 minutes and the vacuum degree is 0.05MPa. Second deodorization stage: The oil is heated to 255℃ and fed into a packed tower for secondary deodorization. The deodorization time in the packed tower is 20 minutes and the vacuum degree is 0.02MPa to obtain deodorized oil.

[0038] S6 Winterization Dewaxing: Add 1% filter aid (diatomaceous earth) and 3.5% activated carbon to the deodorized oil for winterization crystallization at a temperature of 4℃. After reaching the temperature, crystallize for 24 hours, then filter, polish, and obtain the finished oil.

[0039] Example 3 This embodiment discloses a refining method for reducing and controlling the presence of plasticizers and 3-chloropropanol esters in camellia oil, comprising the following steps: S1 Acid Degumming: Heat the camellia oil to 45℃, add 40% food-grade citric acid for acid treatment, the amount added is 0.3% of the oil weight, and the acid treatment time is 10 minutes.

[0040] S2 Alkali Refining and Deacidification: Stir the deacidified oil and heat it to 65°C. Add an alkali solution with a concentration of 25°Bé according to the acid value of camellia oil to carry out a neutralization reaction. The reaction time is 20 minutes. Centrifuge to remove the soap pods generated in the reaction.

[0041] S3 Wash: After desoaping, the camellia oil is washed with purified water at the same temperature at 5% of its weight until it becomes neutral. Then, it is vacuum dried to remove the water from the camellia oil, with the water content not exceeding 0.1% by mass.

[0042] S4 Decolorization: The centrifuged camellia oil is fed into a decolorization tower for decolorization. The amount of activated clay added is 2.5% of the weight of the camellia oil. The decolorization temperature is 120℃ and the decolorization time is 40 minutes to remove the color of the camellia oil. After decolorization, the oil enters the gas separator to remove air and moisture from the oil.

[0043] S5 dual temperature deodorization: First deodorization stage: The oil after gas separation is heated to 200℃ and then pumped into the deodorization tower. The initial vacuum degree in the deodorization tower is controlled at 0.05MPa and maintained for 20min. Then the vacuum degree is adjusted to 0.1MPa and maintained for 25min. Second deodorization stage: The oil is heated to 255℃ and fed into a packed tower for secondary deodorization. The initial vacuum degree in the packed tower is controlled at 0.02MPa and maintained for 10 minutes. Then the vacuum degree is adjusted to 0.05MPa and maintained for 5 minutes to obtain deodorized oil.

[0044] S6 Winterization Dewaxing: Add 1% filter aid (diatomaceous earth) and 3.5% activated carbon to the deodorized oil for winterization crystallization at a temperature of 4℃. After reaching the temperature, crystallize for 24 hours, then filter, polish, and obtain the finished oil.

[0045] Example 4 This embodiment discloses a refining method for reducing and controlling the presence of plasticizers and 3-chloropropanol esters in camellia oil, comprising the following steps: S1 Acid Degumming: Heat the camellia oil to 45℃, add 40% food-grade citric acid for acid treatment, the amount added is 0.3% of the oil weight, and the acid treatment time is 10 minutes.

[0046] S2 Alkali Refining and Deacidification: Stir the deacidified oil and heat it to 65°C. Add an alkali solution with a concentration of 25°Bé according to the acid value of camellia oil to carry out a neutralization reaction. The reaction time is 20 minutes. Centrifuge to remove the soap pods generated in the reaction.

[0047] S3 Wash: After desoaping, the camellia oil is washed with purified water at the same temperature at 5% of its weight until it becomes neutral. Then, it is vacuum dried to remove the water from the camellia oil, with the water content not exceeding 0.1% by mass.

[0048] S4 Decolorization: The centrifuged camellia oil is fed into a decolorization tower for decolorization. The amount of activated clay added is 2.5% of the weight of the camellia oil. The decolorization temperature is 120℃ and the decolorization time is 40 minutes to remove the color of the camellia oil. After decolorization, the oil enters the gas separator to remove air and moisture from the oil.

[0049] S5 dual temperature deodorization: First deodorization stage: The oil after gas separation is heated to 180°C and then pumped into the deodorization tower. The temperature is raised to 190°C within 15 minutes, then maintained at this temperature for 20 minutes, and finally raised to 200°C and maintained for 10 minutes. Meanwhile, the initial vacuum level inside the deodorization tower was controlled at 0.05 MPa and maintained for 20 minutes. Then, the vacuum level was adjusted to 0.1 MPa and maintained for 25 minutes. Second deodorization stage: The oil is heated to 250°C and fed into a packed tower for secondary deodorization. The temperature is then raised to 255°C within 10 minutes and maintained at that temperature for 5 minutes.

[0050] Meanwhile, the initial vacuum degree inside the packed tower is controlled at 0.02 MPa and maintained for 10 minutes. Then, the vacuum degree is adjusted to 0.05 MPa and maintained for 5 minutes to obtain deodorized oil.

[0051] S6 Winterization Dewaxing: Add 1% filter aid (diatomaceous earth) and 3.5% activated carbon to the deodorized oil for winterization crystallization at a temperature of 4℃. After reaching the temperature, crystallize for 24 hours, then filter, polish, and obtain the finished oil.

[0052] Comparative Example 1 This comparative example discloses a method for refining camellia oil, including the following steps: S1 Acid Degumming: Heat the camellia oil to 45℃, add 40% food-grade citric acid for acid treatment, the amount added is 0.3% of the oil weight, and the acid treatment time is 10 minutes; S2 Alkali Refining and Deacidification: Stir the deacidified oil and heat it to 65°C. Add an alkaline solution with a concentration of 25°Bé according to the acid value of camellia oil to carry out a neutralization reaction. The reaction time is 20 minutes. Centrifuge to remove the soap pods generated in the reaction. S3 Wash: After soap removal, the camellia oil is washed with purified water at the same temperature at 5% of its weight until it becomes neutral. Then, it is vacuum dried to remove the water from the camellia oil.

[0053] S4 Decolorization: The centrifuged camellia oil is fed into a decolorization tower for decolorization. The amount of activated clay added is 2.5% of the weight of the camellia oil. The decolorization temperature is 120℃ and the decolorization time is 40 minutes to remove the color of the camellia oil. S5 Deodorization: The decolorized oil enters the gas separator to remove air and moisture from the oil; the gas-separated oil is heated to 260℃ and then pumped into the deodorization tower for 65 minutes to obtain deodorized oil.

[0054] S6 Winterization Dewaxing: Add 1% filter aid and 3.5% activated carbon to the deodorized oil for winterization crystallization at a temperature of 4℃. After reaching the temperature, crystallize for 24 hours, then filter, polish, and obtain the finished oil.

[0055] Performance testing The finished oils from Examples 1-4 and Comparative Example 1 were tested for indicators including acid value, color, plasticizer (DBP, DEHP, DINP) content, 3-chloropropanol ester content, and glycidyl ester content. The specific testing methods and results are as follows: 1. Acid value detection: The acid value of camellia oil was tested using the acid value determination method (KOH titration). The oil sample was mixed with ethanol solvent, phenolphthalein indicator was added, and then titrated with standard potassium hydroxide solution until the solution turned a persistent pink color. The acid value was calculated based on the volume of potassium hydroxide solution consumed in the titration.

[0056] 2. Plasticizer content detection: Gas chromatography-mass spectrometry (GC-MS) was used for qualitative and quantitative analysis of plasticizers in camellia oil, including common plasticizers such as dibutyl phthalate (DBP), di(α-ethylhexyl) phthalate (DEHP), and diisononyl phthalate (DINP). The limits of quantitation (LOQ) for third-party testing were 0.3 mg / kg for DBP, 0.5 mg / kg for DEHP, and 9.0 mg / kg for DINP. Detection below the LQ was indicated as "Not detected (< LQ)".

[0057] 3. The content of 3-chloropropanol ester and glycidyl ester was determined by method 1 of Part II of GB 5009.191-2024 National Food Safety Standard - Determination of chloropropanol and its fatty acid esters and glycidyl esters in food.

[0058] The test results are shown in Table 1 below.

[0059] Table 1 Conclusions: Table 1 shows that under the combined process of low-chloride ion washing, drying control, dual-temperature deodorization, and low-temperature adsorption, the DBP, DEHP, and DINP content in the finished oil of the examples were all below their respective limits of quantification, and the 3-chloropropanol ester and glycidyl ester content were significantly lower than those of Comparative Example 1. Examples 3 and 4 showed a better match between temperature, vacuum, and low-temperature adsorption in the second deodorization stage, resulting in lower levels of 3-chloropropanol ester and glycidyl ester content, while maintaining a low acid value. Comparative Example 1, using a single-stage high-temperature long-term deodorization process, although also undergoing alkali refining and deacidification, showed an increase in the content of 3-chloropropanol ester and glycidyl ester due to the cumulative effect of deodorization intensity.

[0060] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A refining method for reducing and controlling the presence of plasticizers and 3-chloropropanol esters in camellia oil, characterized in that, Includes the following steps: S1 Acid Degumming: Camellia crude oil is heated and then acid-treated to remove phospholipids from the camellia oil, resulting in degummed oil; S2 Alkali Refining and Deacidification: Take the degummed oil obtained in step 1 and perform alkali refining and deacidification to remove free fatty acids from the camellia oil. After centrifugation and soap removal, deacidified oil is obtained. S3 Wash: The desoaped camellia oil is washed with purified water at the same temperature until it is neutral, and then vacuum dried to remove the water from the camellia oil. S4 Decolorization: The dried camellia oil is fed into the decolorization tower for decolorization. After decolorization, the camellia oil enters the gas separator to remove air and moisture from the oil. S5 dual temperature deodorization: First deodorization stage: The camellia oil after gas separation is heated to 180-200℃ and then pumped into the deodorization tower for 40-50 minutes; Second deodorization stage: The camellia oil is heated to 250~260℃ and fed into a packed tower for secondary deodorization. The deodorization time in the packed tower is 10~20 minutes to obtain deodorized oil. S6 Low-Temperature Adsorption: Filter aid and activated carbon are added to the deodorized oil to induce winterization and crystallization. After crystallization, the oil is filtered to obtain the finished product.

2. The refining method for reducing and controlling plasticizers and 3-chloropropanol esters in camellia oil according to claim 1, characterized in that, The first deodorization stage uses a vacuum degree of 0.05~0.1MPa, and the second deodorization stage uses a vacuum degree of 0.02~0.05MPa.

3. The refining method for reducing and controlling plasticizers and 3-chloropropanol esters in camellia oil according to claim 2, characterized in that, The vacuum levels in both the first and second deodorization stages are adjusted gradually. In the first deodorization stage, the initial vacuum level is 0.05~0.08 MPa and is maintained for 20~25 min, then the vacuum level is adjusted to 0.08~0.1 MPa and maintained for 15~25 min. In the second deodorization stage, the initial vacuum level is 0.02~0.03 MPa and is maintained for 5~10 min, then the vacuum level is adjusted to 0.03~0.05 MPa and maintained for 5~10 min.

4. The refining method for reducing and controlling the plasticizer and 3-chloropropanol ester in camellia oil according to claim 1, characterized in that, The temperature control of the first deodorization stage and the second deodorization stage adopts segmented temperature regulation control; the starting temperature of the first deodorization stage is set to 180℃, and the temperature is raised to 185℃ to 190℃ within 10 to 15 minutes, then maintained at this temperature for 20 to 25 minutes, and finally raised to 195℃ to 200℃ and maintained for 5 to 10 minutes; the starting temperature of the second deodorization stage is set to 250℃, and the temperature is raised to 255℃ to 260℃ within 10 to 15 minutes, then maintained at this temperature for 5 to 10 minutes.

5. The refining method for reducing and controlling the plasticizer and 3-chloropropanol ester content in camellia oil according to claim 1, characterized in that, In the S1 acidification and degumming stage, citric acid is used with a mass concentration of 35%~40%, the amount of acid added is 0.2~0.5% of the mass of camellia oil, the acid treatment time is 10~15 min, and the treatment temperature is 40℃~50℃.

6. The refining method for reducing and controlling plasticizers and 3-chloropropanol esters in camellia oil according to claim 1, characterized in that, In the S2 alkali refining and deacidification stage, the concentration of the alkali solution used is 20~25°Bé, the alkali refining temperature is 65~70℃, and the deacidification time is 15~20min.

7. The refining method for reducing and controlling plasticizers and 3-chloropropanol esters in camellia oil according to claim 1, characterized in that, The camellia oil after vacuum drying in the S3 water washing stage has a water content of no more than 0.1% by mass.

8. The refining method for reducing and controlling plasticizers and 3-chloropropanol esters in camellia oil according to claim 1, characterized in that, In the S4 decolorization stage, the decolorizing agent used is activated clay, which is added at a rate of 1.5% to 2.5% of the weight of camellia oil. The decolorization temperature is controlled at 110℃ to 120℃, and the decolorization time is 30 to 50 minutes.

9. The refining method for reducing and controlling the plasticizer and 3-chloropropanol ester in camellia oil according to claim 1, characterized in that, In the S6 low-temperature adsorption stage, the filter aid used is diatomaceous earth, with an addition amount of 1% to 2% of the weight of the deodorized oil, and the addition amount of activated carbon is 3% to 4% of the weight of the deodorized oil. Crystallization is carried out at a crystallization temperature of 2 to 4°C for 18 to 24 hours.

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