A method for rapidly preparing high-purity diglyceride corn oil based on electrochemical reduction reaction

Abstract

This invention belongs to the field of functional oil preparation, specifically a method for rapidly preparing high-purity diacylglycerol (DAG) corn oil based on an electrochemical reduction reaction. This method is implemented by the following steps: first, mixing electrolytes, corn oil, and glycerol, and conducting an electrochemical reaction; then, separating and purifying the product. By controlling the reaction raw materials, reaction parameters, and separation conditions, this method can produce high-purity DAG (over 90%, with 1,3-DAG content exceeding 70%), while also maintaining low levels of byproducts such as 1,2-DAG and free fatty acids, thereby enhancing the product's market competitiveness. The high-purity DAG corn oil produced by this method has potential health benefits and is suitable for use in functional foods, health supplements, and pharmaceuticals. It plays an important role in controlling blood lipids and preventing cardiovascular disease.

Description

Technical Field

[0001] The present invention belongs to the field of functional oil preparation, and specifically relates to a method for rapidly preparing high-purity diacylglycerol (DAG) corn oil based on an electrochemical reduction reaction. Background Art

[0002] Diacylglycerol (DAG), as an important functional lipid, has a wide range of applications in food, cosmetics and medicine, especially in regulating blood lipids and controlling weight, and has received widespread attention.

[0003] Existing methods for producing DAG include chemical synthesis and enzymatic synthesis. Chemical methods have harsh reaction conditions and severe environmental pollution, so enzymatic synthesis is currently the primary method for DAG synthesis. However, enzymatic synthesis is costly, time-consuming, and difficult to achieve selective DAG production. For example, patents (CN202411312663.7 and CN202411133883.3) disclose a two-step method for producing DAG. While this method yields a high DAG content, it is time-consuming and complex. Patents (CN202411168456.9, CN202410998442.3, and CN202410948553.3) also disclose methods for producing DAG products using enzymatic methods, but none address the issues of long DAG production times and numerous byproducts. Therefore, rapidly producing high-purity DAG under mild, environmentally friendly conditions has become a major challenge in this field. Summary of the Invention

[0004] To address the challenges of the existing technology, the present invention provides a method for rapidly preparing high-purity diacylglycerol (DAG) corn oil via electrochemical reduction. This method efficiently produces the specific compound diacylglycerol through electrochemical reduction under mild conditions. By controlling parameters such as electrode materials, potential, and current density, the target product can be selectively produced while minimizing side reactions. The method features a short reaction time, low energy consumption, environmental friendliness, and a high-purity product.

[0005] The technical solutions adopted by the present invention to achieve the above-mentioned purpose are as follows:

[0006] The present invention provides a method for rapidly preparing high-purity diglyceride corn oil, comprising the following steps:

[0007] (1) Add electrolyte to the electrolytic cell, add a mixture of corn oil and glycerol, then add lipase and gallic acid to the electrolytic cell, and slowly add a saturated sodium bicarbonate solution dropwise while stirring to carry out an electrochemical reaction;

[0008] (2) Product separation and purification: After the reaction is completed, the oil and water are separated by centrifugation, the oil phase is taken, DAG is extracted with an organic solvent, and DAG is eluted and purified using a silver ion modified silica gel column.

[0009] Furthermore, in step (1), the volume ratio of the electrolyte to the mixture is 1:4-6; the amount of the lipase added accounts for 1%-2% of the mass of the mixture; the amount of the gallic acid added accounts for 0.2%-0.3% of the mass of the mixture; and the amount of the saturated sodium bicarbonate solution added accounts for 0.2%-0.3% of the mass of the mixture.

[0010] Furthermore, in step (1), the electrolyte is 0.1 M potassium phosphate (K2HPO4) or sodium sulfate (Na2SO4); and the volume ratio of corn oil to glycerol is 3-4:1.

[0011] Furthermore, in step (1), the conditions of the electrochemical reaction are as follows: the electrode material is a carbon-based material (such as carbon black activated carbon) as the anode, and a graphite or platinum electrode is used as the cathode; the electrochemical reaction device is a single-chamber electrolytic cell as the reactor, the anode and cathode are both immersed in the electrolyte solution, and Ag / AgCl is used as the reference electrode.

[0012] Furthermore, in step (1), the reaction temperature of the electrochemical reaction is 25-50 °C, and the current density is controlled at 10-20 mA / cm 2 The potential was set at −0.6 to −1.0 V (relative to the Ag / AgCl reference electrode) and the reaction was carried out for 1.5–2 h.

[0013] Furthermore, in step (2), the centrifugation is carried out at 4500-5000 rpm for 30 min.

[0014] Furthermore, in step (2), the organic solvent is hexane or dichloromethane; and the elution adopts a hexane-ethyl acetate system with a volume ratio of 3:1.

[0015] The beneficial effects of the present invention are:

[0016] (1) High selectivity: DAG is selectively prepared through electrochemical reduction technology. Compared with traditional chemical methods, this method does not require harsh reaction conditions and produces fewer by-products, which is conducive to the separation and purification of the product.

[0017] (2) Green and environmentally friendly: The electrochemical method can be carried out at room temperature and pressure, avoiding the large amount of organic solvents and catalysts used in chemical synthesis, reducing the risk of environmental pollution, and meeting the requirements of green chemical industry.

[0018] (3) High efficiency and energy saving: Compared with enzymatic methods, electrochemical synthesis has obvious advantages in cost and reaction rate. By optimizing electrode materials and reaction conditions, this method can achieve high yields at low energy consumption and is suitable for industrial scale-up production.

[0019] (4) High purity: By controlling the reaction raw materials, reaction parameters and separation conditions, high-purity DAG (more than 90%, of which 1,3-DAG content reaches more than 70%) can be obtained, and the content of by-products such as 1,2-DAG and free fatty acids is low, which is conducive to improving the market competitiveness of the product.

[0020] (5) Broad prospects: The high-purity DAG corn oil prepared by the present invention has potential health benefits and is suitable for application in functional foods, health products and pharmaceutical products. It plays an important role in controlling blood lipids and preventing cardiovascular diseases. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further explained and illustrated by means of specific embodiments below.

[0022] Example 1

[0023] 1. Raw material preparation: Corn oil, glycerol, and lipase are used as the reaction materials. 0.1 M potassium phosphate (K2HPO4) is used as the electrolyte solution. Carbon black is used as the anode, and a platinum electrode is used as the cathode.

[0024] 2. Electrochemical reaction device: The reactor uses a single-chamber electrolytic cell, the anode and cathode are immersed in the electrolyte solution, and Ag / AgCl is used as the reference electrode.

[0025] 3. Reaction conditions setting:

[0026] Temperature control: The reaction temperature was set at 30 °C to maintain mild reaction conditions and avoid the occurrence of side reactions.

[0027] Current density: Control the current density at 10-20 mA / cm 2 to ensure the reaction rate and selectivity of DAG production.

[0028] Potential control: The potential was set between −0.6 and −1.0 V (vs. Ag / AgCl reference electrode) to carry out the electrochemical reduction reaction.

[0029] 4. Electrochemical Reduction Reaction Step: Add 1 / 5 of the electrolyte volume to the electrolytic cell. Add a mixture of corn oil and glycerol to a volume that accounts for 4 / 5 of the cell volume, with a corn oil:glycerol ratio of 3:1. Then, add 2% lipase and 0.2% gallic acid to the cell. Start the electrochemical reaction device and stir the device (180 rpm). During stirring, slowly add a saturated sodium bicarbonate solution (0.3% by weight of the mixture) dropwise. Apply a set current density and potential, and control the reaction time to 2 hours.

[0030] 5. Product separation and purification: After the reaction is completed, centrifuge at 4500-5000 rpm for 30 min to separate the oil and water. Take the oil phase and extract DAG with an organic solvent (such as hexane or dichloromethane). Use silver ion modified silica gel column for purification and elution (hexane-ethyl acetate system, volume ratio 3:1) to separate DAG and other by-products.

[0031] Comparative Example 1

[0032] Steps 1-3 are the same as in Example 1;

[0033] 4. Electrochemical Reduction Step: Add 1 / 5 of the electrolyte volume to the electrolytic cell. Add a mixture of corn oil and glycerol to a volume that accounts for 4 / 5 of the cell volume, with a corn oil:glycerol ratio of 3:1. Then, add lipase at a concentration of 2% by weight of the mixture to the cell. Start the electrochemical reaction unit and stir at 180 rpm. Slowly add a saturated sodium bicarbonate solution at a concentration of 0.3% by weight of the mixture dropwise during stirring. Apply a set current density and potential, and control the reaction time to 2 hours.

[0034] 5. Product separation and purification: After the reaction is completed, centrifuge at 4500-5000 rpm for 30 min to separate the oil and water. Take the oil phase and extract DAG with an organic solvent (such as hexane or dichloromethane). Use silver ion modified silica gel column for purification and elution (hexane-ethyl acetate system, volume ratio 3:1) to separate DAG and other by-products.

[0035] Effect embodiment

[0036] The methods provided in Example 1 and Comparative Example 1 were used to detect the relevant contents; DAG content determination: GB / T26636-2011; Free fatty acids: NY / T 1797 1,3-DAG and 1,2-DAG content: self-developed method, as follows:

[0037] 1. Instruments and Equipment

[0038] 1. Electronic balance: Measuring range: 0-200g; Accuracy: 0.0001g; Status: Within the calibration validity period.

[0039] 2. n-Hexane, chromatographic grade;

[0040] 3. Isopropanol, chromatographic grade;

[0041] 4. Formic acid, chromatographic grade.

[0042] 5. Triglyceride standard: content ≥95.0%, or certified standard solution.

[0043] 6.1,3-Diglyceride standard: content ≥95.0%, or certified standard solution.

[0044] 7.1,2-Diglyceride standard: content ≥95.0%, or certified standard solution.

[0045] 8. Monoglyceride standard: content >95.0%, or certified standard solution.

[0046] 9. High performance liquid chromatograph: with differential detector.

[0047] 10. Disposable microporous filter head: with 0.22 μm microporous filter membrane;

[0048] 2. Testing conditions

[0049] 1. Chromatographic column: C18 (250 mm × 4.6 mm × 5 μm)

[0050] 2. Flow rate: 1.0 mL / min; 3. Column temperature: 35°C; 4. Injection volume: 10 μL

[0051] 3. Running time: 30 minutes

[0052] 4. Mobile phase: n-hexane + isopropanol + formic acid = 20 + 1 + 0.003 (volume fraction)

[0053] 3. Qualitative analysis of standard solutions

[0054] Inject the standard series working solutions into the liquid chromatograph respectively to obtain the corresponding peaks corresponding to the corresponding peak times.

[0055] 4. Sample measurement

[0056] Weigh 0.3 g (accurate to 0.001 g) of the sample into a 10 mL volumetric flask, dissolve it in n-hexane-isopropanol solution (19:1), mix thoroughly, and dilute to the mark. After thorough mixing, filter through a 0.22 μm membrane and analyze by high-performance liquid chromatography.

[0057] 5. Result calculation

[0058] Area normalization method.

[0059] The specific results are shown in Table 1.

[0060] Table 1

[0061]

Claims

1. A rapid preparation method of high-purity diglyceride corn oil, characterized in that: The following steps are involved: (1) Add electrolyte to the electrolytic cell, add a mixture of corn oil and glycerol, then add lipase and gallic acid to the electrolytic cell, and slowly add a saturated sodium bicarbonate solution dropwise while stirring to carry out an electrochemical reaction; (2) Product separation and purification: After the reaction is completed, the oil and water are separated by centrifugation, the oil phase is taken, DAG is extracted with an organic solvent, and DAG is eluted and purified using a silver ion modified silica gel column; In step (1), the volume ratio of the electrolyte to the mixture is 1:4-6; the amount of the lipase added accounts for 1%-2% of the mass of the mixture; the amount of the gallic acid added accounts for 0.2%-0.3% of the mass of the mixture; and the amount of the saturated sodium bicarbonate solution added accounts for 0.2%-0.3% of the mass of the mixture; In step (1), the conditions of the electrochemical reaction are as follows: the electrode material is carbon black as the anode, and the graphite or platinum electrode is used as the cathode; the electrochemical reaction device is: the reactor is a single-chamber electrolytic cell, the anode and cathode are both immersed in the electrolyte solution, and Ag / AgCl is used as the reference electrode; In step (1), the reaction temperature of the electrochemical reaction is 25-50 °C and the current density is controlled at 10-20 mA / cm 2 The potential was set at −0.6 to −1.0 V relative to the Ag / AgCl reference electrode and the reaction was carried out for 1.5–2 h.

2. The method according to claim 1, characterized in that In step (1), the electrolyte is 0.1 M potassium phosphate or sodium sulfate; and the volume ratio of corn oil to glycerol is 3-4:

1.

3. The method according to claim 1, characterized in that In step (2), the centrifugation is carried out at 4500-5000 rpm for 30 min.

4. The method according to claim 1 or 3, characterized in that In step (2), the organic solvent is hexane or dichloromethane; and the elution adopts a hexane-ethyl acetate system with a volume ratio of 3:1.

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