Method for reducing content of 3-chloropropanol ester and glycidyl ester in ethyl ester type fish oil
Treatment of 3-chloropropanol esters and glycidyl esters in ethyl ester fish oil through ethanol aqueous solution and water washing, solving the problem of difficulty in reducing its content in oil processing, achieving extremely low content removal effect, suitable for production and more Healthy edible oils.
Patent Information
- Application Number
- CN202411528412.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2024-12-31
AI Technical Summary
The prior art is difficult to effectively reduce the content of 3-chloropropanol ester and glycidyl ester in oil processing, especially in the oil refining process, it is difficult to control its formation to reach extremely low levels, and the removal effect of adsorbent is limited.
After the ethyl ester fish oil is subjected to transesterification reaction with anhydrous ethanol and an alkaline catalyst, the aqueous ethanol solution is washed and water washed, the 3-chloropropanol esters and glycidyl esters in the fish oil are converted and removed to achieve impurity removal.
This method can significantly reduce the content of 3-chloropropanol ester and glycidyl ester in fish oil, reaching <0.1 mg/kg, meet the requirements of EU and infant edible standards, and the process is simple and easy to operate, suitable for industrial production.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of fish oil purification, and particularly relates to a method for reducing the contents of 3-chloropropanol ester and glycidyl ester in ethyl ester type fish oil. Background Art
[0002] 3-MCPD esters and glycidyl esters are by-products of the oil refining process. Natural oils are fatty acid triglycerides. Due to the presence of glyceryl groups, glyceryl groups will shrink to form glycidyl esters during the oil refining process. In the presence of chloride ions, 3-MCPD esters (3-MCPD esters) will be formed. Glycidyl esters themselves are not carcinogenic, but the glycidol produced by its metabolism in the digestive tract is genetically carcinogenic. Glycidol is rated as a Class 2A carcinogen by the International Cancer Agency. At present, there is no direct evidence that 3-MCPD esters have a negative effect on human health, but studies have shown that 3-MCPD esters will release free 3-MCPD under the action of intestinal pancreatic lipase, and 3-MCPD is rated as a Class 2B carcinogen by the International Cancer Agency.
[0003] At present, the main method to reduce the formation of 3-MCPD esters is to change and optimize the process conditions of oil refining (such as the control of deodorization temperature, deacidification and degumming) from the crude oil end; for glycidyl esters, the content is mostly reduced by adding additional adsorbents. However, although the content of 3-MCPD esters can be controlled to a certain extent by controlling the refining process conditions, it is difficult to control its content at a very low level; and the removal effect of adsorbents on glycidyl esters is also limited. Therefore, in the field of oil processing, there is an urgent need for a method that can further reduce the content of 3-MCPD esters and glycidyl esters in oils and fats, so that it is suitable for application in oil processing enterprises, thereby simply and efficiently producing healthier edible oils and fats. Summary of the invention
[0004] In view of this, the present invention provides a method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester fish oil. The method provided by the present invention is simple and easy to operate, and the content of 3-chloropropanol ester and glycidyl ester in ethyl ester fish oil can be greatly reduced by treating ethyl ester fish oil according to the method provided by the present invention.
[0005] In order to solve the above technical problems, the present invention provides a method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester type fish oil, comprising the following steps: The ethyl ester fish oil, anhydrous ethanol and an alkaline catalyst are mixed for transesterification reaction, and then the ethanol is removed and washed in sequence to obtain the impurity-removed ethyl ester fish oil; The washing includes washing with an ethanol aqueous solution and washing with water, which are performed sequentially.
[0006] Preferably, the temperature of the transesterification reaction is 55-80° C. and the time is 3.5-4.5 h.
[0007] Preferably, the alkaline catalyst comprises sodium hydroxide, sodium ethoxide, sodium methoxide or lipase.
[0008] Preferably, the mass ratio of the ethyl ester fish oil to the alkaline catalyst is 1000:1.0~5.0.
[0009] Preferably, the mass ratio of the ethyl ester fish oil to anhydrous ethanol is 1:0.2-0.6.
[0010] Preferably, the method of removing ethanol is reduced pressure distillation.
[0011] Preferably, the mass concentration of the ethanol aqueous solution for washing with the ethanol aqueous solution is 30-90%.
[0012] Preferably, the mass ratio of the ethyl ester fish oil to the ethanol aqueous solution is 1:0.04-0.1.
[0013] Preferably, the water used for washing is water with a temperature of 50-90°C.
[0014] Preferably, the mass ratio of the ethyl ester fish oil to water is 1:0.2-0.4.
[0015] The present invention provides a method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester fish oil, comprising the following steps: mixing ethyl ester fish oil, anhydrous ethanol and an alkaline catalyst for ester exchange reaction, and then removing ethanol and washing in sequence to obtain ethyl ester fish oil after impurities are removed; the washing comprises washing with ethanol aqueous solution and washing with water in sequence. The present invention uses ethanol to convert 3-chloropropanol ester and glycidyl ester in fish oil into ethanol ester and glyceryl ester through ester exchange reaction, and then removes glyceryl ester through washing with ethanol aqueous solution and washing with water. The method provided by the present invention is simple and easy to operate, and is suitable for industrial production; after the ethyl ester fish oil is treated by the method provided by the present invention, the content of glycidyl ester and 3-chloropropanol ester therein can be controlled at an extremely low level, glycidyl ester <0.1 mg / kg, 3-chloropropanol ester <0.1 mg / kg, which is far lower than the standards of glycidyl ester <1 mg / kg and 3-chloropropanol ester <2.5 mg / kg of edible fish oil formulated by the European Union, and meets the requirements of infant edible standards. DETAILED DESCRIPTION
[0016] The present invention provides a method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester type fish oil, comprising the following steps: The ethyl ester fish oil, anhydrous ethanol and an alkaline catalyst are mixed for transesterification reaction, and then the ethanol is removed and washed in sequence to obtain the impurity-removed ethyl ester fish oil; The washing includes washing with an ethanol aqueous solution and washing with water, which are performed sequentially.
[0017] As a specific embodiment of the present invention, the alkaline catalyst may include sodium hydroxide, sodium ethoxide, sodium methoxide or lipase, and may be specifically sodium hydroxide; the mass ratio of the ethyl ester fish oil to the alkaline catalyst may be 1000:1.0~5.0, and may be specifically 1000:1, 1000:2, 1000:3, 1000:4, 1000:4.5 or 1000:5. As a specific embodiment of the present invention, the mass ratio of the ethyl ester fish oil to anhydrous ethanol may be 1:0.2~0.6, and may be specifically 1:0.2, 1:0.3, 1:0.4, 1:0.5 or 1:0.6.
[0018] As a specific embodiment of the present invention, the mixing may include the following steps: dissolving the alkaline catalyst in a portion of anhydrous ethanol to obtain an alkaline catalyst solution; The ethyl ester fish oil and the remaining part of anhydrous ethanol are first mixed to obtain a first mixed system; The alkaline catalyst solution is added into the first mixed system.
[0019] As a specific embodiment of the present invention, the mass concentration of the alkaline catalyst solution may be 8-12%, and may be specifically 10%.
[0020] As a specific embodiment of the present invention, the temperature of the transesterification reaction can be 55-80°C, or 60-75°C, specifically 65°C, 70°C or 75°C; the time of the transesterification reaction can be 3.5-4.5h, specifically 4h.
[0021] As a specific embodiment of the present invention, the method of removing ethanol can be vacuum distillation. The present invention can recover ethanol through vacuum distillation for recycling.
[0022] As a specific embodiment of the present invention, the mass concentration of the ethanol aqueous solution used for washing with the ethanol aqueous solution can be 30-90%, or 40-80%, or specifically 45%, 50%, 55%, 60%, 65%, 70% or 75%; the mass ratio of the ethyl ester fish oil to the ethanol aqueous solution can be 1:0.04-0.1, or specifically 1:0.04, 1:0.05, 1:0.06, 1:0.07, 1:0.08, 1:0.09 or 1:0.1. As a specific embodiment of the present invention, washing with the ethanol aqueous solution can be specifically mixing the ethanol-removed system and the ethanol aqueous solution in a separating funnel and then standing for separation; the mixing can be carried out under stirring; the stirring time can be 8-12 minutes, or 10 minutes; the standing time can be 25-35 minutes, or 30 minutes. The present invention can remove most of the glyceryl esters generated by the transesterification reaction through washing with the ethanol aqueous solution, avoiding the phenomenon that emulsification occurs by washing with water and it is difficult to achieve washing and impurity removal.
[0023] As a specific embodiment of the present invention, the water used for water washing can be water with a temperature of 50-90°C, or water with a temperature of 60-80°C; the mass ratio of the ethyl ester fish oil to water can be 1:0.2-0.4, or specifically 1:0.3. As a specific embodiment of the present invention, the water washing can be specifically mixing the ethanol aqueous solution washing system and water in a separating funnel and then standing to separate; the mixing can be carried out under stirring; the stirring time can be 4-6 minutes, or 5 minutes; the standing time can be 25-35 minutes, or 30 minutes.
[0024] As a specific embodiment of the present invention, after the water washing, the process may further include: vacuum dehydrating the system after the water washing to obtain the ethyl ester fish oil after the impurities are removed. The present invention has no special requirements for the vacuum dehydration, as long as the water in the system after the water washing can be removed.
[0025] In the present invention, the content of 3-chloropropanol ester in the ethyl ester fish oil after impurities removal is less than or equal to 0.4 mg / kg, and can be less than or equal to 0.1 mg / kg, and the removal rate of 3-chloropropanol ester is 95%; the content of glycidyl ester in the ethyl ester fish oil after impurities removal is less than or equal to 0.4 mg / kg, and can be less than or equal to 0.1 mg / kg.
[0026] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.
[0027] Example 1 2g of sodium hydroxide is dissolved in anhydrous ethanol to obtain a sodium hydroxide ethanol solution with a mass concentration of 10%; 1000g of ethyl ester fish oil and 500g of anhydrous ethanol are put into a 3L flask, and then the sodium hydroxide ethanol solution is added, and the esterification reaction is carried out at 75°C for 4h, and the ethanol is recovered by vacuum distillation and then transferred to a separatory funnel, and a 50% ethanol aqueous solution with a mass concentration of 0.05 times the weight of the oil is added, and the bottom waste liquid is discharged after stirring for 10min and standing for 30min; then, water with a temperature of 60°C, which is 0.3 times the weight of the oil, is added, stirred for 5min, and the waste liquid is discharged after standing for 30min; after vacuum dehydration, 984g of ethyl ester fish oil after impurity removal is obtained.
[0028] The contents of glycidyl ester and 3-chloropropanol ester in ethyl ester fish oil and ethyl ester fish oil after impurity removal were tested according to AOCS Cd 29b-13 method. The results are listed in Table 1.
[0029] Table 1 Contents of glycidol and 3-chloropropanol esters in ethyl ester fish oil before and after treatment As can be seen from Table 1, the method provided by the present invention can be used to treat ethyl ester fish oil to significantly reduce the content of glycidyl ester and 3-chloropropanol ester therein, the removal rate of glycidyl ester is 95.5%, and the removal rate of 3-chloropropanol ester is 98.7%; and the oil loss rate is low during the treatment process.
[0030] Example 2 Dissolve 5g of sodium hydroxide in anhydrous ethanol to obtain a sodium hydroxide ethanol solution with a mass concentration of 10%; put 1000g of ethyl ester fish oil and 500g of anhydrous ethanol into a 3L flask, then add the sodium hydroxide ethanol solution, perform esterification reaction at 75°C for 4h, recover ethanol by vacuum distillation, and then transfer to a separatory funnel, add 50% ethanol aqueous solution with a mass concentration of 0.1 times the weight of the oil, stir for 10min, let stand for 30min, and then discharge the bottom waste liquid; then add 0.3 times the weight of the oil water with a temperature of 60°C, stir for 5min, let stand for 30min, and then discharge the waste liquid; after vacuum dehydration, obtain 952g of ethyl ester fish oil after impurity removal.
[0031] The contents of glycidyl ester and 3-chloropropanol ester in ethyl ester fish oil and ethyl ester fish oil after impurity removal were tested according to AOCS Cd 29b-13 method. The results are listed in Table 2.
[0032] Table 2 Contents of glycidol and 3-chloropropanol esters in ethyl ester fish oil before and after treatment Example 3 2g of sodium hydroxide is dissolved in anhydrous ethanol to obtain a sodium hydroxide ethanol solution with a mass concentration of 10%; 1000g of ethyl ester fish oil and 200g of anhydrous ethanol are put into a 3L flask, and then the sodium hydroxide ethanol solution is added, and the esterification reaction is carried out at 75°C for 4h, and the ethanol is recovered by vacuum distillation and then transferred to a separatory funnel, and a 50% ethanol aqueous solution with a mass concentration of 0.1 times the weight of the oil is added, and the bottom waste liquid is discharged after stirring for 10min and standing for 30min; then, water with a temperature of 60°C, which is 0.3 times the weight of the oil, is added, stirred for 5min, and the waste liquid is discharged after standing for 30min; after vacuum dehydration, 980g of ethyl ester fish oil after impurity removal is obtained.
[0033] The contents of glycidyl ester and 3-chloropropanol ester in ethyl ester fish oil and ethyl ester fish oil after impurity removal were tested according to AOCS Cd 29b-13. The results are shown in Table 3.
[0034] Table 3 Contents of glycidol and 3-chloropropanol esters in ethyl ester fish oil before and after treatment Comparative Example 1 Dissolve 5g of sodium hydroxide in anhydrous ethanol to obtain a sodium hydroxide ethanol solution with a mass concentration of 10%; put 1000g of ethyl ester fish oil and 500g of anhydrous ethanol into a 3L flask, add the sodium hydroxide ethanol solution, and react at 75℃ for 4h for esterification. After vacuum distillation to recover ethanol, transfer to a separatory funnel, add 0.1 times the weight of the oil and 90℃ hot water, stir at 20r / min for 15s, the oil will be severely emulsified and cannot be separated when left standing.
[0035] Comparative Example 2 Dissolve 5g of sodium hydroxide in anhydrous ethanol to obtain a sodium hydroxide ethanol solution with a mass concentration of 10%; put 1000g of ethyl ester fish oil and 500g of anhydrous ethanol into a 3L flask, then add the sodium hydroxide ethanol solution, and react at 75℃ for 4h for esterification. After recovering ethanol by vacuum distillation, transfer to a separatory funnel, add 90℃ hot salt water with a volume of 0.1 times the weight of the oil, stir for 10min, let stand for 30min, and then release the bottom waste liquid; then add 90℃ water with a volume of 0.3 times the weight of the oil, stir for 5 minutes, the oil will be emulsified and cannot be separated when left standing.
[0036] As can be seen from Tables 1 to 3, the method provided by the present invention can be used to treat ethyl ester fish oil to significantly reduce the content of glycidyl ester and 3-chloropropanol ester therein; it can be seen from Comparative Examples 1 and 2 that the system after the transesterification reaction is not first subjected to an ethanol aqueous solution, but first subjected to salt washing or direct water washing, the impurity soap stock in the oil cannot be well removed, resulting in emulsification of the oil during the secondary water washing. Compared with the comparative example, the embodiment can clean the impurity soap stock in the oil by washing once with a small amount (5%) of ethanol aqueous solution, and no emulsification phenomenon will occur during the secondary water washing.
[0037] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.
Claims
1. A method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester fish oil, characterized in that: The following steps are involved: The ethyl ester fish oil, anhydrous ethanol and an alkaline catalyst are mixed for transesterification reaction, and then the ethanol is removed and washed in sequence to obtain the impurity-removed ethyl ester fish oil; The washing includes washing with an ethanol aqueous solution and washing with water, which are performed sequentially.
2. The method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester type fish oil according to claim 1, characterized in that: The temperature of the transesterification reaction is 55-80° C. and the time is 3.5-4.5 hours.
3. The method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester type fish oil according to claim 1, characterized in that: The alkaline catalyst includes sodium hydroxide, sodium ethoxide, sodium methoxide or lipase.
4. The method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester type fish oil according to claim 1 or 3, characterized in that: The mass ratio of the ethyl ester fish oil to the alkaline catalyst is 1000:1.0-5.
0.
5. The method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester type fish oil according to claim 1, characterized in that: The mass ratio of the ethyl ester fish oil to anhydrous ethanol is 1:0.2-0.
6.
6. The method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester type fish oil according to claim 1, characterized in that: The method for removing ethanol is reduced pressure distillation.
7. The method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester fish oil according to claim 1, characterized in that: The mass concentration of the ethanol aqueous solution for washing with the ethanol aqueous solution is 30-90%.
8. The method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester fish oil according to claim 7, characterized in that: The mass ratio of the ethyl ester fish oil to the ethanol aqueous solution is 1:0.04-0.
1.
9. The method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester fish oil according to claim 1, characterized in that: The water used for washing is water with a temperature of 50-90°C.
10. The method for reducing the content of 3-chloropropanol ester and glycidyl ester in ethyl ester type fish oil according to claim 9, characterized in that: The mass ratio of the ethyl ester fish oil to water is 1:0.2-0.4.