Method for reducing aldehydes and ketones in cooking oil heated by edible oil
A novel refining method using negative pressure-cavitation coupled adsorbents solves the problem of aldehyde and ketone formation caused by high-temperature refining, achieving a reduction in aldehyde and ketone concentration and maintenance of oil quality at low temperatures, and is applicable to the edible oil processing industry.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING TECH & BUSINESS UNIV
- Filing Date
- 2026-03-20
- Publication Date
- 2026-05-26
AI Technical Summary
The high-temperature processing in existing edible oil refining processes increases the amount of aldehydes and ketones generated, and traditional methods have failed to effectively block the generation of aldehydes and ketones at the source, affecting the health of edible oils and the pollution of cooking fumes.
A novel refining method employing negative pressure-cavitation coupled adsorbents replaces traditional high-temperature decolorization and deodorization steps by treating edible oils with a mixture of montmorillonite, cyclodextrin, calcium chloride, and activated clay using ultrasonic equipment and composite adsorbents under negative pressure.
Under low-temperature conditions, the concentration of aldehydes and ketones in the fumes from heating cooking oil is significantly reduced, preserving the natural antioxidant properties of the oil, reducing health risks and oil fume pollution, which aligns with the concept of green and environmentally friendly development.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of edible oil processing and quality control technology, and relates to a method for reducing aldehyde and ketone compounds in fumes from heating edible oil. Background Technology
[0002] When edible vegetable oils are used for cooking, especially during stir-frying and deep-frying, a large amount of fumes are produced. These fumes contain a large number of volatile organic compounds (VOCs), including aldehydes, ketones, alcohols, alkanes, and organic acids. Long-term exposure to environments rich in these substances can seriously harm the human respiratory tract and lungs. Among VOCs, aldehydes are the most abundant, accounting for 30.6%–74.6%. These aldehydes are highly reactive and contribute to the formation of ozone and particulate matter. Furthermore, formaldehyde, acetaldehyde, and butenal are classified as Group 1, Group 2B, and Group C carcinogens by the IARC, respectively. Numerous studies have shown that most aldehydes and ketones in cooking fumes are highly irritating and toxic to human health, and are among the main culprits behind the health threats posed by cooking fumes. In the field of aldehyde and ketone pollution control from cooking fumes, researchers have focused primarily on end-of-pipe treatment, while patents related to blocking the formation of aldehydes and ketones at the source of edible oil production are relatively scarce. In fact, blocking the formation of aldehydes and ketones at the source of edible oil is one of the key strategies for achieving emission reduction. Among the many factors that affect the amount of aldehydes and ketones formed during heating, the role of oil refining is particularly crucial. After processing such as degumming, deacidification, and deodorization, oils can effectively remove components that easily trigger oxidation reactions, such as free fatty acids, thereby significantly reducing the amount of aldehydes and ketones formed during heating.
[0003] Refined Grade 1 oil typically has a fume point exceeding 190℃, resulting in significantly lower fume emissions during hot cooking compared to unrefined crude oil. This is a core reason for its popularity among consumers. However, traditional refining processes have significant drawbacks: the decolorization process requires adsorption treatment at 90-120℃, and the deodorization process must be completed in a high-temperature environment above 240℃. This high-temperature processing damages the oil's original natural antioxidant system. Reports indicate that oils refined at high temperatures have approximately 20% lower heating stability than crude oil, and their trans fatty acid content increases by 1.5-3 times. Potentially hazardous substances such as 3-chloropropanol esters are also generated due to high-temperature reactions. More importantly, high-temperature refining leads to a 30%-50% loss of trace components such as polyphenols, tocopherols, and phytosterols in edible oils, reducing their antioxidant properties and actually increasing the formation of aldehydes and ketones during subsequent cooking.
[0004] Therefore, breaking through the limitations of traditional high-temperature processes and developing new low-temperature refining technologies to avoid the generation of risk factors and maximize the retention of natural beneficial components in oils, thereby reducing the emission of aldehydes and ketones in cooking fumes from the source of edible oils, is of great significance for green cooking and improving kitchen air quality. Summary of the Invention
[0005] To address the above problems, this invention provides a method for reducing aldehyde and ketone compounds in cooking fumes from heating edible oil. This method refines the neutralized oil using a novel refining process, significantly reducing the concentration of aldehyde and ketone compounds in the fumes. It offers advantages such as low-temperature efficiency, simple process, and convenient operation.
[0006] The present invention employs the following technical solution to solve the above problems: A method for reducing aldehyde and ketone compounds in fumes from heating edible oil, the method mainly involves refining the edible oil using a negative pressure-cavitation coupled adsorbent.
[0007] Specifically, the method includes the following steps: Step 1: Place the pretreated edible oil in a negative pressure-cavitation reactor to react and obtain primary treated oil; Step 2: After adding the composite adsorbent to the primary treated oil and mixing, the mixture is placed in the negative pressure-cavitation reaction device for reaction again to obtain the secondary treated oil. Step 3: Centrifuge the secondary processed oil and take the supernatant after centrifugation, which is the refined oil.
[0008] As a preferred approach, the negative pressure in step 1 of the above method can be provided by a vacuum pump, and the cavitation reaction can be carried out in any ultrasonic device.
[0009] More preferably, the ultrasonic equipment includes, but is not limited to, ultrasonic cleaners, ultrasonic cell disruptors, ultrasonic reactors, ultrasonic probe devices, and other customized ultrasonic-assisted reaction devices.
[0010] As a preferred method, the pretreated edible oil in step 1 of the above method includes, but is not limited to, one or more crude vegetable oils such as rapeseed oil, soybean oil, tea seed oil, soybean oil, camellia seed oil, olive oil, soybean oil, and sunflower seed oil that have undergone degumming and / or deacidification.
[0011] As a preferred method, the reaction conditions in step 1 of the above method are: vacuum degree -0.5~-0.1Mpa, cavitation power 100-150W, and temperature 30~45℃.
[0012] As a preferred method, the amount of composite adsorbent used in step 2 of the above method is 0.5 to 1.5% of the weight of the primary treated oil.
[0013] As a preferred embodiment, the preparation method of the composite adsorbent in step 2 of the above method is as follows: Montmorillonite, cyclodextrin, calcium chloride, and water are mixed in a weight ratio of 1:(0.8-1.2):1:(1.5-2.0), stirred at 60-70℃, dried, ground, and sieved to obtain a mixed powder; the mixed powder is then mixed with activated clay in a weight ratio of 1:(4-5) to obtain the mixed adsorbent.
[0014] As a preferred method, the reaction conditions in step 2 of the above method are: temperature 50~60℃, cavitation power 300~350W, and vacuum degree -0.2~-0.1Mpa.
[0015] The present invention has the following beneficial effects: This invention provides a method for reducing the concentration of aldehydes and ketones in cooking fumes from the source of edible vegetable oils. It utilizes a negative pressure-cavitation coupled adsorbent instead of high-temperature decolorization and deodorization to lower the concentration of aldehydes and ketones in cooking fumes, offering advantages such as energy saving and environmental protection. This method not only solves the potential risks associated with traditional refining processes, making edible oils healthier while ensuring quality, but also reduces oil fume pollution at its source, playing a positive role in improving indoor air quality and reducing health threats caused by inhaling cooking fumes.
[0016] The adsorbent used in this invention can ensure the refining of crude vegetable oil at temperatures below 60°C. Combined with negative pressure-cavitation reaction, it replaces the traditional decolorization and deodorization refining steps. It can ensure the refining effect under relatively low temperature conditions, effectively avoid the shortcomings of traditional high-temperature refining of edible vegetable oil, and is in line with the current green and environmentally friendly development concept, providing a new way for the sustainable development of the edible oil processing industry. Detailed Implementation
[0017] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope of protection of the claims of this application.
[0018] Example 1 Step 1: Weigh 300g of deacidified rapeseed oil and place it in a reactor. Connect the reactor to a vacuum circulating water pump to create a negative pressure environment. Then transfer the reactor to an ultrasonic cleaner and continue the reaction for 15 minutes at a temperature of 30℃, a power of 100W, and a vacuum of -0.2MPa. After that, adjust the temperature to 40℃, the power to 150W, and the vacuum to -0.1MPa, and continue the reaction for 15 minutes. After the reaction is completed, cool to room temperature and slowly break the vacuum to obtain the primary treated oil. Step 2: Add 1.0% of the mixed adsorbent prepared by the following method to the primary treated oil, mix well, and place it again in the above negative pressure reactor. Then transfer the reactor to an ultrasonic cleaner and continue the reaction for 20 minutes at a temperature of 60°C, a power of 350W, and a vacuum of -0.2MPa. After the reaction is completed, cool to room temperature and slowly break the vacuum to obtain the secondary treated oil. Step 3: Centrifuge the secondary processed oil at 1000 r / min for 30 min, and collect the supernatant after centrifugation, which is the refined rapeseed oil; Preparation of the above mixed adsorbent: Montmorillonite, cyclodextrin, calcium chloride, and water are mixed in a weight ratio of 1:1.2:1:2.0, stirred at 70°C with a magnetic stirrer for 30 min, dried in an oven at 105°C, ground, and passed through a 50-mesh sieve to obtain a mixed powder; the mixed powder is then mixed with activated clay in a weight ratio of 1:4 to obtain the mixed adsorbent.
[0019] Example 2 Step 1: Weigh 300g of deacidified peanut oil and place it in a reactor. Connect the reactor to a vacuum circulating water pump to create a negative pressure environment. Then transfer the reactor to an ultrasonic cleaner and continue the reaction for 10 minutes at a temperature of 35℃, a power of 100W, and a vacuum of -0.5MPa. After that, adjust the temperature to 45℃, the power to 150W, and the vacuum to -0.2MPa, and continue the reaction for 10 minutes. After the reaction is completed, cool to room temperature and slowly break the vacuum to obtain the primary treated oil. Step 2: Add 1.5% of the mixed adsorbent prepared by the following method to the primary treated oil, mix well, and place it again in the above negative pressure reactor. Then transfer the reactor to an ultrasonic cleaner and continue the reaction for 30 minutes at a temperature of 50°C, a power of 300W, and a vacuum of -0.1MPa. After the reaction is completed, cool to room temperature and slowly break the vacuum to obtain the secondary treated oil. Step 3: Centrifuge the secondary processed oil at 1000 r / min for 30 min, and collect the supernatant after centrifugation, which is the refined peanut oil; Preparation of the above mixed adsorbent: Montmorillonite, cyclodextrin, calcium chloride, and water are mixed in a weight ratio of 1:0.8:1:1.5, stirred at 60°C with a magnetic stirrer for 30 min, dried in an oven at 105°C, ground, and passed through a 50-mesh sieve to obtain a mixed powder; the mixed powder is then mixed with activated clay in a weight ratio of 1:5 to obtain the mixed adsorbent.
[0020] Example 3 Step 1: Weigh 300g of deacidified soybean oil and place it in a reactor. Connect the reactor to a vacuum circulating water pump to create a negative pressure environment. Then transfer the reactor to an ultrasonic cleaner and continue the reaction for 13 minutes at a temperature of 35℃, a power of 100W, and a vacuum of -0.3MPa. After that, adjust the temperature to 40℃, the power to 150W, and the vacuum to -0.1MPa, and continue the reaction for 13 minutes. After the reaction is completed, cool to room temperature and slowly break the vacuum to obtain the primary treated oil. Step 2: Add 0.5% of the mixed adsorbent prepared by the following method to the primary treated oil, mix well, and place it again in the above negative pressure reactor. Then transfer the reactor to an ultrasonic cleaner and continue the reaction for 25 minutes at a temperature of 60°C, a power of 300W, and a vacuum of -0.1MPa. After the reaction is completed, cool to room temperature and slowly break the vacuum to obtain the secondary treated oil. Step 3: Centrifuge the secondary processed oil at 1000 r / min for 30 min, and collect the supernatant after centrifugation, which is the refined soybean oil; Preparation of the above mixed adsorbent: Montmorillonite, cyclodextrin, calcium chloride and water are mixed in a weight ratio of 1:1:1:1.8, stirred at 70°C with a magnetic stirrer for 30 min, dried in an oven at 105°C, ground and passed through a 50-mesh sieve to obtain a mixed powder; the mixed powder is mixed with activated clay in a weight ratio of 1:4.5 to obtain the mixed adsorbent.
[0021] Comparative Example 1 Weigh 300g of deacidified rapeseed oil (same batch as in Example 1) and 1.0% of activated clay by weight of the oil, and place them together in a reactor. Connect the reactor to a vacuum circulating water pump to create a negative pressure environment. Then transfer the reactor to a constant temperature magnetic stirrer and continue the reaction for 30 minutes at a temperature of 110℃, a vacuum of -0.2MPa, and a stirring speed of 500rpm. After the reaction is completed, cool to room temperature, slowly break the vacuum, transfer to a centrifuge tube, and centrifuge at 1000r / min for 30 minutes. Collect the supernatant after centrifugation, which is the refined rapeseed oil. Comparative Example 2 Step 1: Weigh 300g of deacidified rapeseed oil (same batch as in Example 1) and place it in a reactor. Connect the reactor to a vacuum circulating water pump to create a negative pressure environment. Then transfer the reactor to an ultrasonic cleaner and continue the reaction for 15 minutes at a temperature of 30°C, a power of 300W, and a vacuum of -0.2MPa. After the reaction is completed, cool to room temperature and slowly break the vacuum to obtain the primary treated oil. Step 2: Add a mixed adsorbent (montmorillonite, calcium chloride, and activated clay mixed in a weight ratio of 0.1:0.1:10) to the primary treated oil, mix well, and place it back into the negative pressure reactor. Then transfer the reactor to an ultrasonic cleaner and continue the reaction for 20 minutes at a temperature of 60°C, a power of 350W, and a vacuum of -0.2MPa. After the reaction is completed, cool to room temperature and slowly break the vacuum to obtain the secondary treated oil. Step 3: Centrifuge the secondary processed oil at 1000 r / min for 30 min, and collect the supernatant after centrifugation, which is the refined rapeseed oil; Comparative Example 3 Step 1: Weigh 300g of deacidified peanut oil (same batch as in Example 2) and place it in a reactor. Connect the reactor to a vacuum circulating water pump to create a negative pressure environment. Then transfer the reactor to an ultrasonic cleaner and continue the reaction for 10 minutes at a temperature of 35°C, a power of 100W, and a vacuum of -0.5MPa. Then adjust the temperature to 45°C, a power of 150W, and a vacuum of -0.2MPa, and continue the reaction for 10 minutes. After the reaction is completed, cool to room temperature and slowly break the vacuum to obtain the primary treated oil. Step 2: Add activated carbon equivalent to 1.5% of the oil weight to the primary treated oil, mix well, and place it again in the above negative pressure reactor. Then transfer the reactor to an ultrasonic cleaner and continue the reaction for 30 minutes at a temperature of 50°C, a power of 300W, and a vacuum of -0.1MPa. After the reaction is completed, cool to room temperature and slowly break the vacuum to obtain the secondary treated oil. Step 3: Centrifuge the secondary processed oil at 1000 r / min for 30 min, and collect the supernatant after centrifugation, which is the refined peanut oil; Comparative Example 4 Weigh 300g of deacidified peanut oil (same batch as in Example 2) and place the mixed adsorbent prepared by the following method, equivalent to 1.5% of the oil weight, into a reactor. Connect the reactor to a vacuum circulating water pump to create a negative pressure environment. Then transfer the reactor to an ultrasonic cleaner and continue the reaction for 30 minutes at a temperature of 50°C, a power of 300W, and a vacuum of -0.1MPa. After the reaction is completed, cool to room temperature, slowly break the vacuum, transfer to a centrifuge tube, and centrifuge at 1000r / min for 30 minutes. Collect the supernatant after centrifugation, which is the refined peanut oil. Preparation of the above mixed adsorbent: Montmorillonite, cyclodextrin, calcium chloride, and water are mixed in a weight ratio of 1:0.8:1:1.5, stirred at 60°C with a magnetic stirrer for 30 min, dried in an oven at 105°C, ground, and passed through a 50-mesh sieve to obtain a mixed powder; the mixed powder is then mixed with activated clay in a weight ratio of 1:5 to obtain the mixed adsorbent.
[0022] Comparative Example 5 Step 1: Weigh 300g of deacidified soybean oil (same batch as in Example 3) and place the mixed adsorbent prepared by the following method, equivalent to 0.5% of the oil weight, into a reactor. Connect the reactor to a vacuum circulating water pump to create a negative pressure environment. Then transfer the reactor to a magnetic stirrer and continue the reaction for 30 minutes at a temperature of 60°C, a vacuum of -0.2MPa, and a stirring speed of 500rpm. After the reaction is completed, cool to room temperature, slowly break the vacuum, transfer to a centrifuge tube, and centrifuge at 1000r / min for 30 minutes. Collect the supernatant after centrifugation, which is the refined soybean oil. Preparation of the above mixed adsorbent: Montmorillonite, cyclodextrin, calcium chloride and water are mixed in a weight ratio of 1:1:1:1.8, stirred at 70°C with a magnetic stirrer for 30 min, dried in an oven at 105°C, ground and passed through a 50-mesh sieve to obtain a mixed powder; the mixed powder is mixed with activated clay in a weight ratio of 1:4.5 to obtain the mixed adsorbent.
[0023] Performance testing I. Quality Evaluation of Refined Oil The acid value and peroxide value of the refined oil obtained in different implementation methods were tested with reference to the national standards GB 5009.229-2025 "National Food Safety Standard - Determination of Acid Value in Food" and GB5009.227-2023 "National Food Safety Standard - Determination of Peroxide Value in Food".
[0024] Results and Analysis As can be seen from the results in Table 1, the method described in this invention can significantly reduce the acid value and peroxide value of refined oil, and the effect is significantly better than that of refined oil in each comparative example.
[0025] Table 1 Comparison of acid value and peroxide value in different refined oils II. Determination of Aldehyde and Ketone Compound Content in Heating Fumes from Edible Oils In accordance with the standard "HJ683-2014 Determination of Aldehydes and Ketones in Ambient Air by High Performance Liquid Chromatography", the content of aldehydes and ketones in the heating fumes of refined oil was determined.
[0026] Weigh 80g of oil and heat it to 220℃. According to GB / T18883-2022 "Indoor Air Quality Standard", set up a QC-6H dual-path constant flow sampler in the average breathing zone of Chinese residents (1400 mm above the ground and 500 mm from the center of the pot). When the oil starts to heat, use the sampler to collect aldehyde and ketone compounds in the oil fumes and collect the aldehyde and ketone compounds into the DNPH aldehyde and ketone collection column. The process lasts for 30 minutes.
[0027] Elute the aldehydes and ketones from the DNPH column to a 10mL volumetric flask using 5mL of chromatographic grade acetonitrile. After dilution to volume, take 1mL of the diluted sample solution, filter it through a 0.22μm organic filter membrane, and then transfer it to a 2mL brown vial. Store the vial at -20℃ for subsequent detection of aldehydes and ketones.
[0028] The aldehyde and ketone compounds analyzed mainly consist of 13 types, namely formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, butenal, 2-butanone, methacrolein, n-butanal, benzaldehyde, pentanal, m-methylbenzaldehyde, and hexanal.
[0029] Testing conditions: UltiMate 3000 high-performance liquid chromatograph, Venusil MPC 18 Chromatographic column; Mobile phase: acetonitrile-water; Column temperature: 30℃; The mobile phase flow rate was 1.0 mL / min; the sample injection volume was 20 μL; and the detection wavelength was 360 nm. The gradient elution procedure is as follows: Aldehyde and ketone compound standard solutions with mass concentrations of 0.1 μg / mL, 0.2 μg / mL, 0.5 μg / mL, 1.0 μg / mL, and 2.0 μg / mL were prepared. The aldehyde and ketone compounds in the samples were qualitatively and quantitatively analyzed by plotting standard curves and using the external standard method.
[0030] The contents of aldehyde and ketone compounds in the heating fumes of refined oils with different treatments and those in the heating fumes of commercially available Grade 1 oil (i.e., edible oil refined through conventional degumming, deacidification, decolorization, and deodorization processes, without the addition of antioxidants) were determined according to the above method.
[0031] Results and analysis: As can be seen from the results in Table 2, the refined oil prepared by the method of the present invention has a low concentration of aldehyde and ketone compounds in the fumes after heating, indicating that the method of the present invention can effectively reduce the concentration of aldehyde and ketone compounds in the fumes of edible oil heating.
[0032] Table 2. Total concentrations (μg / m³) of 13 aldehydes and ketones in heating fumes from different refined oils 3 )
Claims
1. A method for reducing aldehyde and ketone compounds in fumes from heating edible oil, characterized in that, The method involves refining edible oils using a negative pressure-cavitation coupled adsorbent; the method includes the following steps: Step 1: Place the pretreated edible oil in a negative pressure-cavitation reactor to react and obtain primary treated oil; Step 2: After adding the composite adsorbent to the primary treated oil and mixing, the mixture is placed in the negative pressure-cavitation reaction device for reaction again to obtain the secondary treated oil. Step 3: Centrifuge the secondary processed oil and take the supernatant after centrifugation, which is the refined oil.
2. The method as described in claim 1, characterized in that, The pretreated edible oil mentioned in step 1 is crude vegetable oil that has undergone degumming and / or deacidification.
3. The method as described in claim 1, characterized in that, In step 1, the cavitation reaction is carried out in an ultrasonic device.
4. The method as described in claim 3, characterized in that, The ultrasonic equipment includes an ultrasonic cleaner, an ultrasonic cell disruptor, an ultrasonic reactor, an ultrasonic probe device, and a customized ultrasonic-assisted reaction device.
5. The method as described in claim 1, characterized in that, The reaction conditions in step 1 are: vacuum degree -0.5~-0.1Mpa, cavitation power 100-150W, and temperature 30~45℃.
6. The method as described in claim 1, characterized in that, In step 2, the amount of composite adsorbent used is 0.5 to 1.5% of the weight of the primary treated oil.
7. The method as described in claim 1, characterized in that, The preparation method of the composite adsorbent in step 2 is as follows: Montmorillonite, cyclodextrin, calcium chloride, and water are mixed and stirred at 60-70℃, dried, and ground to obtain a mixed powder. The mixed powder is then mixed with activated clay to obtain a mixed adsorbent.
8. The method as described in claim 7, characterized in that, The montmorillonite, cyclodextrin, calcium chloride, and water are in a weight ratio of 1:(0.8-1.2):1:(1.5-2.0).
9. The method as described in claim 7, characterized in that, The weight ratio of the mixed powder to the activated clay is 1:(4-5).
10. The method as described in claim 1, characterized in that, The reaction conditions in step 2 are: temperature 50~60℃, cavitation power 300~350W, and vacuum degree -0.2~-0.1Mpa.