Unsaturated oil refining method and device based on enzyme coupling

Abstract

The invention relates to the technical field of edible vegetable oil processing, and particularly discloses an unsaturated oil refining method and device based on enzyme-material coupling. Conversion of main impurities is completed at low temperature by utilizing high specificity of biological enzyme; according to the method, side reactions such as grease hydrolysis, oxidation, trans-fatty acid generation and nutrient loss caused by high temperature and strong alkali are avoided from the source, a brand new process route of coupling front-end bio-enzyme precise catalysis and rear-end physical means mild treatment is created for the first time, impurities and waxiness are removed through a mild, efficient and oriented refining process, and meanwhile, the yield is improved. The natural color and trace active components of the edible vegetable oil are perfectly reserved, generation of harmful substances such as trans-fatty acid and chloropropanol ester is avoided, and the problems of nutrient loss, generation of risky substances, environmental unfriendliness and the like in a traditional edible vegetable oil refining process are systematically solved; the method is especially suitable for highly unsaturated grease which is extremely sensitive to heat and oxidation and needs to retain natural color and luster.

Description

Technical Field

[0001] This application relates to the field of edible vegetable oil processing technology, and specifically discloses a method and apparatus for refining unsaturated oils based on enzyme-molecule coupling. Background Technology

[0002] Oil refining is a crucial process for removing free fatty acids (FFA), phospholipids, waxes, pigments, odor substances, and other impurities from crude vegetable oils to obtain safe, stable, and edible oils. For high-end functional oils such as flaxseed oil and safflower oil, they are not only rich in essential polyunsaturated fatty acids like alpha-linolenic acid and linoleic acid, but also contain natural nutrients such as tocopherols, sterols, and chlorophyll. However, their extremely high degree of unsaturation and abundance of heat-sensitive components make them highly susceptible to oxidation, isomerization, and thermal degradation during processing, imposing extremely stringent requirements on the refining process.

[0003] Currently, the main refining technologies used in industry include: 1. Traditional chemical refining method: This is currently the most mainstream process, typically including steps such as degumming, alkali refining and deacidification, adsorption decolorization, and high-temperature deodorization. While it can effectively reduce FFA and phospholipid content, it suffers from drawbacks such as significant loss of nutrients, generation of hazardous substances, and environmental and yield issues.

[0004] 2. Pure physical refining method: This method omits the alkali refining step and mainly relies on distillation under high temperature and high vacuum to remove FFA. Although it avoids the generation of soap residue and the use of lye, it still does not solve the core contradictions brought about by high temperature: such as stringent requirements for raw materials, unavoidable heat damage, and functional limitations.

[0005] 3. Bio-enzymatic refining: As an emerging green technology, enzymatic methods are carried out under mild conditions and have the advantages of high specificity and mild reaction conditions. However, its application alone has obvious shortcomings such as long processing cycle, process limitations, and cost factors.

[0006] It is evident that traditional chemical and physical refining, relying on high temperatures, inevitably lead to nutrient loss and the formation of hazardous substances. While simple enzymatic refining, though operating under mild conditions, suffers from low efficiency, inability to resolve wax residues, and failure to achieve efficient synergy with downstream physical processing units. Therefore, this invention provides a method and apparatus for refining unsaturated oils based on enzyme-chemical coupling to address the aforementioned problems. Summary of the Invention

[0007] The purpose of this invention is to solve the problems of nutrient loss, generation of hazardous substances, and environmental unfriendliness in traditional edible vegetable oil refining processes, so as to form an integrated process chain that does not require chemical decolorization, can efficiently dewax, and is low-temperature controllable throughout the process, thereby meeting the current technological gap and urgent needs in the field of high-end functional oil processing.

[0008] To achieve the above objectives, the basic solution of the present invention provides a method for refining unsaturated oils based on enzyme-molecule coupling, comprising the following steps: Step S1: Enzymatic degumming and deacidification are carried out by adding phospholipase and citrate buffer to crude oil at 45-55℃. After reacting for 2-4 hours, immobilized lipase is added. After solid-liquid separation, clear oil is obtained. Step S2, dynamic crystallization dewaxing coupled with ultrasound, cool the clear oil to 2-8℃ for crystallization, apply treatment for 4-10 hours, and perform solid-liquid separation at 5-10℃ to obtain dewaxed oil; Step S3, adsorption purification and odor precursor removal: The dewaxed oil is heated to 60-70℃ and purified by passing it through one or more adsorption columns connected in series to obtain purified oil. Step S4, low-temperature stripping deodorization and final purification: first deodorize at low temperature, then heat the purified oil to 120-130℃ for stripping, the stripping time is less than 30 minutes, and after stripping, cool to below 60℃ to obtain refined oil; Step S5, Natural Antioxidant Network Construction: Refined oil cooled to 40-50°C is precisely mixed online with a synergistic natural antioxidant system, and the finished oil is obtained after filtration.

[0009] Furthermore, step S1 includes: Step S101: Preheat the crude oil to 45-55℃; Step S102: Add 0.01-0.05% by weight of phospholipase and citrate buffer to the heated crude oil to convert non-hydrated phospholipids into hydrated phospholipids. Step S103: Immobilized lipase at 0.1-0.5% of oil weight is directly added to the system to catalyze the esterification reaction between free fatty acids and trace amounts of added food-grade monoglycerides or glycerol to generate neutral glycerides. The reaction time is 3-6 hours. Step S104: Hydrated phospholipid gum and immobilized enzymes are removed by gentle centrifugation or membrane separation to obtain degummed and deacidified clear oil.

[0010] Furthermore, step S2 includes: Step S201: The enzyme-treated clear oil is slowly cooled to the wax crystallization range of 2-8℃ at a programmed controlled rate. During the cooling and crystal growth process, ultrasonic treatment with a frequency of 25-40kHz and a power density of 15-35W / L is continuously applied. The total cooling and crystal growth time is 4-10h. In step S202, after crystal growth is completed, a rotary drum filter is used to perform solid-liquid separation at 5-10℃ to completely remove wax and residual trace solid impurities, thereby obtaining dewaxed oil.

[0011] Furthermore, in step S3, the adsorption medium is a composite material modified by surface oleophilic-hydrophobic balance, which is a food-grade silica gel and a synthetic zeolite composite with a specific pore size, or a mixture of mesoporous activated carbon and an inert polymer carrier.

[0012] Furthermore, step S4 includes: Step S401: First, use a packed tower or plate tower to perform short-time low-temperature deodorization on the purified oil; Step S402: Then, the purified oil is rapidly heated to 120-130℃ under an absolute pressure ≤300Pa, and food-grade superheated steam that has been deoxygenated is introduced as a stripping agent. The amount of steam used is 0.3-1.0% of the oil weight. The deodorization temperature is strictly ≤130℃ and the residence time is ≤30 minutes. In step S403, the deodorized oil is rapidly cooled to below 60°C using a plate heat exchanger to obtain refined oil.

[0013] Furthermore, in step S5, the natural antioxidant system includes: Primary antioxidant: 0.03-0.08% mixed tocopherol concentrate; Synergists and metal chelating agents: 0.005-0.02% phospholipids; Co-antioxidant: 0.01-0.04% rosemary extract, rich in carrageenan and carrageenanol.

[0014] Based on the same inventive concept, this invention provides an unsaturated oil refining apparatus based on enzyme coupling, comprising: Enzymatic degumming and deacidification system: includes a heater for heating crude oil, an enzyme reaction vessel for containing crude oil for enzymatic reaction, and a membrane filter for filtering crude oil after enzymatic reaction. A dynamic crystallization dewaxing system coupled with ultrasound includes a crystallization tank for cooling and containing clear oil crystals, an ultrasonic generator for applying ultrasound to the crystallization tank, and a rotary drum filter for filtering the crystallized clear oil. Adsorption purification and odor precursor removal system: including a heat exchanger for heating dewaxed oil and an adsorption column for purifying and adsorbing tractors; Low-temperature stripping deodorization and final purification system: including a low-temperature deodorization tower for deodorizing purified oil at low temperature, a heater for heating the deodorized oil after low-temperature deodorization, a stripping tower for stripping the deodorized oil, and a cooler for cooling the stripped oil. Natural antioxidant network construction system: including blending tanks for containing the mixture of refined oil and natural antioxidant system and terminal filters for filtering the mixed oil.

[0015] Furthermore, the drum filter includes: A rack, on which a machine compartment is provided; The filter cartridge is rotatably connected inside the machine compartment and is driven to rotate by a power component located on the frame. The filter cartridge is equipped with filter cloth. The negative pressure chamber is located on one side of the filter cartridge and is connected to a negative pressure nitrogen pipeline. The injection chamber is located at the top of the filter cartridge and is connected to a nitrogen injection pipe; The collection tank is located directly below the blow chamber and is connected to a negative pressure suction pipe.

[0016] Furthermore, the drum filter also includes: The heat-insulating jet pipe is located on the outside of the filter cylinder on the side away from the negative pressure chamber, and the heat-insulating jet pipe is provided with several nozzles facing the filter cylinder. A collection hood is positioned opposite the heat-insulating spray pipe and located inside the filter cylinder. The collection hood is connected to a negative pressure suction pipe.

[0017] Furthermore, a gap is formed between the two sides of the collection tank and the filter cloth, and an adjustment component is provided inside the machine compartment to seal the gap. The adjustment component includes: A receiving box, wherein a wedge block is slidably connected to the inside of the receiving box along the radial direction of the filter cylinder, and a spring is provided between the wedge block and the bottom surface of the receiving box; The slider is slidably connected to the collection tank along the radial direction of the filter cylinder, with one end of the slider facing the inner wall of the filter cylinder and equipped with a sealing plate; A connecting rod, wherein both ends of the connecting rod are respectively provided with connecting posts that are connected to the wedge and the slider; The filter cylinder is provided with a baffle that can compress the wedge.

[0018] The principle and effect of this solution are as follows: 1. This method utilizes the high specificity of biological enzymes to complete the transformation of major impurities at low temperatures, avoiding side reactions such as oil hydrolysis, oxidation, trans fatty acid formation, and nutrient loss caused by high temperatures and strong alkalis from the source. It is the first to create a new process route that couples precise front-end biological enzyme catalysis with gentle back-end physical treatment. While removing impurities and waxes through a gentle, efficient, and targeted refining process, it perfectly preserves the natural color and trace active ingredients, and avoids the formation of harmful substances such as trans fatty acids and chloropropanol esters. It systematically solves the problems of nutrient loss, formation of hazardous substances, and environmental unfriendliness in traditional edible vegetable oil refining processes. It is especially suitable for highly unsaturated oils that are extremely sensitive to heat and oxidation and need to retain their natural color.

[0019] 2. Addressing the challenge of temperature control in physical dewaxing, the rotary drum filter of this invention employs a crystal stripping method that first adsorbs and fixes the crystals to prevent them from falling back, followed by concentrated blowing to remove the fallen crystals. This method achieves a high crystal stripping rate and minimizes ineffective crystal circulation within the filtration system. Furthermore, it automatically forms a sealed space at the moment of blowing and collection, significantly reducing nitrogen and crystal leakage and improving the utilization efficiency of the blowing gas and the crystal collection rate. This not only effectively replaces the scraper and filter cloth in traditional rotary drum filters, ensuring real-time cleaning of the filter cloth while preventing localized overheating due to friction, but also actively manages the temperature of the filter cloth through an insulated blowing pipe. This maintains the filter cloth at a suitable and uniform temperature before immersion in the oil, effectively preventing the negative impact of excessively low or high filter cloth temperatures on oil quality and filtration rate, and improving the temperature uniformity and controllability of the entire dewaxing process. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A flowchart of an unsaturated oil refining method based on enzyme-molecule coupling proposed in an embodiment of this application is shown; Figure 2 This illustration shows a schematic diagram of the external structure of a rotary drum filter in an unsaturated oil refining device based on enzyme-molecule coupling, as proposed in an embodiment of this application. Figure 3 This illustration shows a schematic diagram of the internal structure of a rotary drum filter in an unsaturated oil refining device based on enzyme-molecule coupling, as proposed in an embodiment of this application. Figure 4 It shows Figure 3 Enlarged view of section A in the middle. Detailed Implementation

[0022] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0023] The reference numerals in the accompanying drawings include: frame 1, machine compartment 2, feed pipe 3, servo motor 4, end cover 5, rotating sleeve 6, connector 7, connecting plate 701, partition 702, arc plate 8, discharge pipe 9, first sealing plate 10, second sealing plate 11, negative pressure chamber 12, spray chamber 13, collection trough 14, heat-insulating spray pipe 15, collection cover 16, receiving box 17, wedge block 18, spring 19, slider 20.

[0024] A method for refining unsaturated oils based on enzyme-product coupling, implementing, for example... Figure 1 As shown, it includes the following steps: Step S1: Enzymatic synergistic degumming and deacidification Step S101: Preheat flaxseed or safflower seed crude oil to the optimal temperature for enzyme activity, 45-55℃. Step S102: Add 0.01-0.05% of the oil weight of phospholipase and an appropriate amount of citrate buffer to the heated crude oil. The phospholipase used is phospholipase A1 or A2. React for 2-4 hours under gentle stirring to convert non-hydrated phospholipids into hydrated phospholipids. Maintain the pH of the solution at 5.0-5.5 by controlling an appropriate amount of citrate buffer. In step S103, without separating the colloids, 0.1-0.5% (by weight of oil) of immobilized lipase is directly added to the system. The immobilized lipase is derived from Lipase B of Candida antarctica and exhibits 1,3-specificity or non-specificity. At the same temperature, this enzyme catalyzes the esterification reaction of free fatty acids with trace amounts of added food-grade monoglycerides or glycerol to generate neutral glycerides. The reaction time is 3-6 hours.

[0025] In step S104, after the reaction is complete, the hydrated phospholipid gum and immobilized enzyme can be removed by gentle centrifugation or membrane separation to obtain degummed and deacidified clear oil.

[0026] In traditional processes, degummed gums and impurities carry away neutral oil, reducing yield. Alkali refining and deacidification, on the other hand, saponify free fatty acids (FFA) and discharge them as waste, resulting in an oil loss of approximately 1-1.5 times that of FFA. This method continuously performs degumming and deacidification in a single reaction system without pre-separating the gums. Phospholipase hydrolyzes one of the fatty acids in the non-hydrated phospholipids of calcium and magnesium phosphatidylcholine, generating more hydrophilic lysophospholipids, which can then be removed by hydration and centrifugation. Immobilized lipase catalyzes the esterification reaction between residual FFA and added monoglycerides or glycerol in the system, converting FFA back into triglycerides, resulting in neutral oil. This not only removes FFA but also directly contributes to the refining yield, leading to a significant increase in actual yield.

[0027] Step S2, Dynamic crystallization dewaxing coupled with ultrasound Step S201 involves slowly cooling the enzyme-treated oil to the wax crystallization range of 2-8°C at a programmed controlled rate. During the cooling and subsequent crystal growth process, ultrasonic treatment at a frequency of 25-40kHz and a power density of 15-35W / L is continuously applied. The total cooling and crystal growth time is 4-10 hours.

[0028] Ultrasonic cavitation serves two main purposes: One is to promote uniform nucleation: increase the number of crystal nuclei, making the wax crystals smaller and more uniform; Secondly, it inhibits excessive crystal growth: it disrupts the formation of crystal clusters and prevents the formation of large, loose crystals that are difficult to separate.

[0029] This process ultimately results in a dense, robust, and easily filterable crystal structure, significantly shortening crystal growth time, improving centrifugation or filtration efficiency, and reducing wax and oil entrainment losses.

[0030] Step S202: After crystal growth is completed, immediately use a rotary drum filter at 5-10℃ to separate solids and liquids, thoroughly remove wax and residual trace solids, and obtain dewaxed oil.

[0031] Step S3: Adsorption purification and removal of odor precursors The dewaxed oil is heated to 60-70°C and pumped through one or more adsorption columns connected in series to obtain purified oil. The adsorption medium is a composite material modified for surface oleophilic-hydrophobic balance, such as a food-grade silica gel composite with a synthetic zeolite of a specific pore size, such as microporous zeolite with a pore size in the range of 0.5-2.0 nm, or hierarchical porous zeolite with mesopores of 2-50 nm, or a mixture of mesoporous activated carbon and an inert polymer support. The adsorption process is carried out under inert gas protection and can selectively adsorb polar impurities and aldehyde and ketone precursors. This step aims to remove trace amounts of enzymatic hydrolysis products, pigment oxides, and odor precursors that may remain after enzyme treatment without affecting the natural pigments.

[0032] Traditional decolorization methods, while adsorbing pigments, also adsorb large amounts of beneficial components such as tocopherols and sterols, and generate waste bleaching clay pollution. This method completely eliminates the high-dose activated clay and activated carbon decolorization steps found in traditional processes. Utilizing polar adsorption and molecular sieve effects, it selectively adsorbs trace amounts of polar impurities and small-molecule odor precursors from oils, while exhibiting weaker adsorption of larger molecular weight, structurally stable natural pigments. Thus, while purifying the oils, it preserves their natural color and nutritional components to the greatest extent possible.

[0033] Step S4, Low-temperature stripping deodorization and final purification Step S401: First, use a packed tower or plate tower to perform short-time low-temperature deodorization on the purified oil.

[0034] In step S402, the purified oil is then rapidly heated to the highest temperature point of this process, 120-130℃, under an absolute pressure ≤300Pa. Food-grade superheated steam, treated with deoxygenation, is introduced as a stripping agent, with the steam volume being 0.3-1.0% of the oil weight. Under these mild steam distillation conditions, residual low-threshold volatile odor substances are effectively removed, and potentially present trace amounts of esters, such as chloropropanol esters, are also decomposed. The key control points for this step are: deodorization temperature strictly ≤130℃ and residence time ≤30 minutes.

[0035] In step S403, the deodorized oil is rapidly cooled to below 60°C using a plate heat exchanger to obtain refined oil.

[0036] Step S5, Construction of Natural Antioxidant Network Step S501 involves precisely blending the refined oil, cooled to 40-50°C, with an online synergistic natural antioxidant system. This system comprises: Primary antioxidant: 0.03-0.08% mixed tocopherol concentrate; Synergists and metal chelating agents: 0.005-0.02% phospholipids; Co-antioxidant: 0.01-0.04% rosemary extract, rich in carrageenan and carrageenanol.

[0037] Step S502: After the refined oil and the natural antioxidant system are mixed evenly, the mixture is polished and filtered through a terminal filter with an absolute precision of 1-3μm to ensure the ultimate purity and physical stability of the product, thus obtaining the finished oil.

[0038] Step S503: Finally, the finished oil is packaged with nitrogen.

[0039] In this method, the temperature and time of the enzyme reaction step can be finely adjusted according to the specific crude oil quality and enzyme activity, but the upper limit of the temperature for the physical dewaxing and deodorization steps is the core condition for protecting the quality of the oil.

[0040] In physical dewaxing, if the temperature is too high, such as >10℃, the wax, being a mixture of high-molecular-weight alkanes, has a wide melting point range. When the separation temperature approaches or exceeds the melting point of some wax components, the already formed fine, dense crystals will partially soften and dissolve. This causes some of the wax that should have been removed to re-dissolve in the oil, increasing the turbidity of the dewaxed oil and decreasing its cold stability. After refrigeration, it is prone to appearing as a mist or flocculent substance. The separated wax cake is also sticky due to its high oil content, making it difficult to process. Furthermore, the increased temperature weakens the intermolecular forces that maintain the wax crystal structure, causing the fine, dense aggregates formed by ultrasound to become loose and soft. This makes the loose crystals easily broken under vacuum suction, and the fine wax particles penetrate the filter cloth or the gaps between the discs, resulting in incomplete solid-liquid separation and an increase in residual solid impurities in the oil. At the same time, the oil content of the wax cake increases significantly, causing a decrease in refining yield.

[0041] However, if the temperature is too low, such as below 5°C, the viscosity of vegetable oils is highly sensitive to temperature. For every 10°C decrease in temperature, the viscosity may more than double. Excessive cooling can cause the oil to become abnormally viscous. This results in high flow resistance in the centrifuge or difficulty in effective vacuum suction, leading to slow separation speed and reduced production capacity. Viscous and viscous oils are also more likely to coat and adhere to the surface of wax crystals and the interior of the filter cake, making them difficult to separate completely, resulting in more oil in the wax cake and yield loss. Furthermore, to overcome the resistance caused by high viscosity, the equipment needs to operate at higher power, increasing energy consumption. In addition to waxes, some oils may contain small amounts of high-melting-point triglycerides or sterols. Excessively low temperatures may induce the unintended precipitation of these non-target components, co-crystallizing with the waxes. This not only alters the characteristics of the wax crystals, affecting separation, but may also unnecessarily change the fatty acid composition and physical properties of the dewaxed oil, such as causing unnecessary turbidity at room temperature.

[0042] Based on the same inventive concept, another embodiment of the present invention provides an unsaturated oil refining apparatus based on enzyme coupling, such as... Figure 1 As shown, it includes: Enzymatic degumming and deacidification system: includes a heater for heating crude oil, an enzyme reaction vessel for containing crude oil for enzymatic reaction, and a membrane filter for filtering crude oil after enzymatic reaction. A dynamic crystallization dewaxing system coupled with ultrasound includes a crystallization tank for cooling and containing clear oil crystals, an ultrasonic generator for applying ultrasound to the crystallization tank, and a rotary drum filter for filtering the crystallized clear oil. Adsorption purification and odor precursor removal system: including a heat exchanger for heating dewaxed oil and an adsorption column for purifying and adsorbing tractors; Low-temperature stripping deodorization and final purification system: including a low-temperature deodorization tower for deodorizing purified oil at low temperature, a heater for heating the deodorized oil after low-temperature deodorization, a stripping tower for stripping the deodorized oil, and a cooler for cooling the stripped oil. Natural antioxidant network construction system: including blending tanks for containing the mixture of refined oil and natural antioxidant system and terminal filters for filtering the mixed oil.

[0043] In comparison, the deodorization temperature of ≤130℃ in the stripping tower is relatively easy to control, while temperature control is more difficult in physical dewaxing. For example, in the drum filter, the surface moisture of the filter cloth exposed to cold air may freeze, clogging the pores and forming a low-temperature area; the continuous friction between the scraper and the filter cloth during unloading will generate heat, forming a high-temperature area, which will cause some oil to be at high and low temperatures, thus causing the above-mentioned technical problems.

[0044] Based on this, the drum filter in this embodiment is as follows: Figure 2 and Figure 3 As shown, the device includes a frame 1, a housing 2 mounted on the frame 1, and a filter cartridge rotatably connected within the housing 2. The frame 1 is symmetrically equipped with end caps 5 that are rotatably and sealingly connected to both ends of the filter cartridge. O-rings are disposed between the outer wall of the filter cartridge and the outer wall of the end caps 5. A feed pipe 3 is connected to the center of one of the end caps 5. One side of the filter cartridge extends out of the housing 2 and is driven to rotate by a power component. The power component is a servo motor 4. The output shaft of the servo motor 4 meshes with a gear ring on the outer wall of the filter cartridge via a drive gear, thereby driving the entire filter cartridge to rotate through the gear ring.

[0045] The filter cylinder includes a rotating sleeve 6 that is rotatably and sealingly connected to the end caps 5 at both ends, and several connecting parts 7 disposed between the rotating sleeves 6. Multiple arc-shaped plates 8 are laid between the connecting parts 7, and filter cloth is arranged between adjacent connecting parts 7 on the inner wall of the filter cylinder. After the crystal growth is completed, the oil and crystal mixture enters the interior of the filter cylinder through the feed pipe 3. The filter cloth filters the oil and crystal. After filtration, the oil is discharged from the discharge pipe 9 located at the bottom of the machine compartment 2, while the crystal is attached to the surface of the filter cloth and located on the side of the filter cloth closer to the center of the filter cylinder.

[0046] Correspondingly, a first sealing plate 10 and a second sealing plate 11 are configured inside the housing 2, wherein the first sealing plate 10 is located on the path of the filter cartridge rotating upwards from the bottom, as shown below. Figure 3 As shown, the filter cylinder rotates clockwise as a whole. The first sealing plate 10 is located on the left side of the filter cylinder, while the second sealing plate 11 is located on the top of the filter cylinder. A collection trough 14 is provided between the end caps 5 on both sides, located directly below the second sealing plate 11.

[0047] The outer wall of the first sealing plate 10 is provided with a negative pressure chamber 12, and a negative pressure nitrogen pipeline is connected inside the negative pressure chamber 12. The side of the first sealing plate 10 facing the filter cylinder is provided with several negative pressure suction ports connected to the negative pressure nitrogen pipeline. The outer wall of the second sealing plate 11 is provided with a spray chamber 13, and a nitrogen spray pipeline is connected to the spray chamber 13. The side of the second sealing plate 11 facing the filter cylinder is provided with several air nozzles connected to the nitrogen spray pipeline. Correspondingly, a first collection cover 16 facing the filter cylinder is provided in the collection tank 14, and a negative pressure suction pipe is connected to the collection tank 14.

[0048] In this configuration, when the filter cloth on the filter cylinder passes the first sealing plate 10, it is mainly subjected to the negative pressure adsorption effect of the negative pressure nitrogen pipeline. The crystals are tightly adsorbed on the surface of the filter cloth, and some oil is sucked into the negative pressure nitrogen pipeline. After oil-gas separation, it is recycled. When the filter cloth on the filter cylinder passes the second sealing plate 11, it is mainly subjected to the combined action of the nitrogen blowing pipeline and the negative pressure suction pipe. The nitrogen blowing causes the crystals to fall off the filter cloth and are sucked out through the first collection hood 16 and the negative pressure suction pipe. After solid-gas separation, they are collected.

[0049] This method can effectively replace the role of scrapers and filter cloth in traditional drum filters, ensuring real-time cleaning of the filter cloth while preventing localized overheating caused by friction.

[0050] The connector 7 includes a connecting plate 701 connected to the rotating sleeves 6 on both sides and a partition 702 connected to the connecting plate 701 and arranged radially along the filter cylinder. The filter cloth is arranged between two adjacent connecting plates 701. The servo motor 4 drives the filter cylinder to rotate intermittently at the included angle between adjacent partitions 702, for example, 45° intermittent rotation, that is, the filter cylinder rotates one position of the filter cloth each time. By utilizing the cooperation between the partition 702 and the first sealing plate 10 and the second sealing plate 11, a relatively sealed environment is formed between the partition 702, the first sealing plate 10 or the second sealing plate 11, and the filter cloth, thereby improving the negative pressure adsorption effect of the negative pressure nitrogen pipeline and the blowing effect of the nitrogen blowing pipeline.

[0051] However, since the crystals adhere to the inner wall of the filter cloth, the filter cloth needs to gradually rotate from outside the collection tank 14 to directly above the collection tank 14 during rotation. This requires a certain gap to be left on the top side of the collection tank 14 to prevent the end of the collection tank 14 from directly contacting the filter cloth. The reason for this is that direct contact between the end of the collection tank 14 and the filter cloth will not only cause friction and heat generation between the end of the collection tank and the filter cloth, which will cause the oil to heat up when the filter cloth is immersed in the oil again, but the end of the collection tank may also act as a scraper in a traditional rotary drum filter, scraping off the crystals attached to the filter cloth, causing the crystals to fall back into the filter cylinder and mix with the oil, increasing the processing burden.

[0052] However, due to the gap between the top side of the collection tank 14 and the filter cloth, when the nitrogen blowing pipe and negative pressure suction pipe clean the filter cloth located directly above the collection tank 14, some crystals and air may overflow from the gap, reducing the cleaning effect. Therefore, if... Figure 4 As shown, an adjustment assembly is symmetrically arranged inside the housing 2. The adjustment assembly includes a receiving box 17 mounted on the end cover 5, a wedge 18 slidably connected inside the receiving box 17 and squeezed by the end of the partition 702, and a spring 19 disposed between the wedge 18 and the bottom surface of the receiving box 17. The receiving box 17 is arranged radially along the filter cylinder, so that the wedge 18 slides radially along the filter cylinder. The adjustment assembly also includes a slider 20 slidably connected inside the collection groove 14. The slider 20 also slides radially along the filter cylinder. One end of the slider 20 faces the inner wall of the connecting plate 701 and is provided with a sealing plate adapted to the connecting plate 701. Both the wedge 18 and the slider 20 are provided with connecting posts laterally. The two connecting posts pass through the end cover 5 and are provided with connecting rods. Correspondingly, the end cover 5 is provided with a through groove that allows the connecting posts to slide. The wedge 18 and the slider 20 are connected to each other by the two connecting posts and the connecting rods, so that the wedge 18 and the slider 20 move synchronously.

[0053] In this configuration, when the partition 702 is not engaged with the wedge 18, the wedge 18 and the slider 20 are acted upon by the spring 19, creating a gap between the sealing plate and the filter cloth. When the partition 702 contacts the wedge 18, it gradually compresses the wedge 18, causing the slider 20 and the sealing plate to gradually approach the filter cloth, reducing or even sealing the gap, thus creating a relatively sealed environment. When the filter cylinder rotates, causing a filter unit separated by the partition 702 to rotate directly above the collection tank 14, the end of the partition 702 of this unit will compress the wedge 18, driving the sealing plate on the slider 20 side to move towards the filter cloth via the linkage mechanism, thereby automatically reducing or sealing the gap, forming a relatively sealed blowing and collecting chamber. After the unit rotates, the spring 19 resets the wedge 18 and the sealing plate, restoring the gap and preventing unnecessary friction with the filter cloth.

[0054] like Figure 3 As shown, on the right side of the filter cylinder, there are a heat-insulating spray pipe 15 located outside the filter cylinder and a collection cover 16 located inside the filter cylinder. The collection cover 16 is also connected to a negative pressure pipe. The heat-insulating nozzle pipe is equipped with several nozzles facing the filter cylinder. Nitrogen gas at 5-10°C is supplied into the heat-insulating nozzle pipe to heat-insulate the filter cloth that is about to be immersed in the oil, so as to achieve final cleaning and maintain the filter cloth at a suitable temperature.

[0055] The working process of the drum filter in this embodiment is as follows: After crystal growth, the oil and crystal mixture enter the filter cylinder through the feed pipe 3. The servo motor 4 drives the filter cylinder to rotate intermittently clockwise at 45°. The negative pressure pipes in the negative pressure nitrogen pipe, the heat insulation blowing pipe 15, and the collection hood 16 are in a normally open state. The negative pressure pipes in the nitrogen blowing pipe and the collection tank 14 are intermittently opened. Specifically, when the filter cylinder rotates, the negative pressure pipes in the nitrogen blowing pipe and the collection tank 14 are closed, and when the filter cylinder stops rotating, the negative pressure pipes in the nitrogen blowing pipe and the collection tank 14 are opened.

[0056] Most of the oil passes through the filter cloth from the bottom of the filter cylinder and is discharged from the discharge pipe 9. When the filter cloth on the filter cylinder detaches from the oil, the crystals are tightly adsorbed on the surface of the filter cloth by the negative pressure adsorption of the negative pressure nitrogen pipe to prevent the crystals from falling back into the filter cylinder and mixing with the oil. Some of the oil is sucked into the negative pressure nitrogen pipe and then recycled after oil-gas separation. The servo motor 4 drives the filter cylinder to continue rotating, so that the filter cloth rotates to directly above the collection hood 16. The partition 702 gradually squeezes the wedge 18, driving the slider 20 and the sealing plate to gradually approach the filter cloth, reducing the gap or even sealing the gap. In this relatively sealed environment, nitrogen is used to blow the crystals off the filter cloth and suck them out through the first collection hood 16 and the negative pressure suction pipe. After solid-gas separation, they are collected. Then the servo motor 4 drives the filter cylinder to continue rotating, passing between the collection hood 16 and the heat-insulating blowing pipe 15 for blowing treatment. This final cleaning is done while maintaining the filter cloth at a suitable temperature.

[0057] The rotary drum filter in this embodiment employs a crystal stripping method that first adsorbs and fixes the crystals to prevent them from falling back, and then uses concentrated blowing to remove the crystals. This method results in a high crystal stripping rate and minimizes ineffective crystal circulation within the filtration system. Furthermore, it automatically forms a sealed space at the moment of blowing and collection, greatly reducing the leakage of nitrogen and crystals, and improving the utilization efficiency of the blowing gas and the crystal collection rate. It can effectively replace the scraper and filter cloth in traditional rotary drum filters, ensuring real-time cleaning of the filter cloth while preventing localized overheating due to friction. Moreover, the insulated blowing pipe 15 actively manages the temperature of the filter cloth, keeping it at a suitable and uniform temperature before immersion in the oil. This effectively prevents the negative impact of excessively low or high filter cloth temperatures on oil quality and filtration rate, and improves the temperature uniformity and controllability of the entire dewaxing process.

[0058] The application of this method and apparatus to treat high-acid-value cold-pressed flaxseed oil (acid value 5.0 mg KOH / g) and high-wax safflower seed oil shows the following significant advantages compared to control processes (traditional chemical refining and purely physical refining): Safety indicators: Trans fatty acid content <0.1%; 3-MCPD ester and 2-MCPD ester were not detected (<0.005mg / kg).

[0059] Nutritional retention: Total tocopherol retention rate ≥92%; Total phytosterol retention rate ≥88%.

[0060] Physicochemical and sensory properties: Acid value ≤ 0.15 mg KOH / g; Peroxide value ≤ 1.0 mmol / kg; Wax content < 10 ppm; Clear and transparent after refrigeration at 0℃ for 24 hours; The oil has the typical fresh flavor of the raw material and no off-odor.

[0061] Oxidative stability (Rancimat method, 110℃): The oxidation induction period is extended by more than 80% compared to crude oil and by 40% compared to traditional refined oil.

[0062] Throughout the entire process, the maximum temperature of this method and apparatus is ≤130℃, and there are no strong acids, strong alkalis, or bleaching clay, effectively protecting heat-sensitive nutrients and natural pigments, preserving nutrition and color. Furthermore, this method avoids the use of chloride ions and high temperatures from the source, eliminating the precursors and conditions for the formation of 3-chloropropanol esters (GE). The high-temperature deodorization process is strictly controlled below 130℃ and within 30 minutes, far below the critical conditions for the large-scale formation of trans fatty acids (TFA), effectively eliminating hazardous substances. At the same time, this method uses an enzymatic step with no chemical wastewater; the physical adsorption step requires a small amount of adsorbent, which may be renewable; and the overall water consumption, energy consumption, and solid waste emissions are significantly reduced, achieving the goal of green environmental protection.

[0063] This method and apparatus utilize the high specificity of biological enzymes to complete the conversion of major impurities at low temperatures, thus avoiding side reactions such as oil hydrolysis, oxidation, trans fatty acid formation, and nutrient loss caused by high temperatures and strong alkalis. It abandons the harsh chemical treatment mode of traditional processes involving strong acid degumming, strong alkali deacidification, and high-temperature deodorization, pioneering a new process route that couples precise front-end biological enzyme catalysis with gentle back-end physical treatment. This systematically solves the problems of nutrient loss, hazardous substance formation, and environmental unfriendliness in traditional edible vegetable oil refining processes. It is particularly suitable for highly unsaturated oils that are extremely sensitive to heat and oxidation and require the preservation of their natural color.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any indirect modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for refining unsaturated oils based on enzyme-product coupling, characterized in that, Includes the following steps: Step S1: Enzymatic degumming and deacidification are carried out by adding phospholipase and citrate buffer to crude oil at 45-55℃. After reacting for 2-4 hours, immobilized lipase is added. After solid-liquid separation, clear oil is obtained. Step S2, dynamic crystallization dewaxing coupled with ultrasound, cool the clear oil to 2-8℃ for crystallization, apply treatment for 4-10 hours, and perform solid-liquid separation at 5-10℃ to obtain dewaxed oil; Step S3, adsorption purification and odor precursor removal: The dewaxed oil is heated to 60-70℃ and purified by passing it through one or more adsorption columns connected in series to obtain purified oil. Step S4, low-temperature stripping deodorization and final purification: first deodorize at low temperature, then heat the purified oil to 120-130℃ for stripping, the stripping time is less than 30 minutes, and after stripping, cool to below 60℃ to obtain refined oil; Step S5, Natural Antioxidant Network Construction: Refined oil cooled to 40-50°C is precisely mixed online with a synergistic natural antioxidant system, and the finished oil is obtained after filtration.

2. The method for refining unsaturated oils based on enzyme-molecule coupling according to claim 1, characterized in that, Step S1 includes: Step S101: Preheat the crude oil to 45-55℃; Step S102: Add 0.01-0.05% by weight of phospholipase and citrate buffer to the heated crude oil to convert non-hydrated phospholipids into hydrated phospholipids. Step S103: Immobilized lipase at 0.1-0.5% of oil weight is directly added to the system to catalyze the esterification reaction between free fatty acids and trace amounts of added food-grade monoglycerides or glycerol to generate neutral glycerides. The reaction time is 3-6 hours. Step S104: Hydrated phospholipid gum and immobilized enzymes are removed by gentle centrifugation or membrane separation to obtain degummed and deacidified clear oil.

3. The method for refining unsaturated oils based on enzyme-molecule coupling according to claim 1, characterized in that, Step S2 includes: Step S201: The enzyme-treated clear oil is slowly cooled to the wax crystallization range of 2-8℃ at a programmed controlled rate. During the cooling and crystal growth process, ultrasonic treatment with a frequency of 25-40kHz and a power density of 15-35W / L is continuously applied. The total cooling and crystal growth time is 4-10h. In step S202, after crystal growth is completed, a rotary drum filter is used to perform solid-liquid separation at 5-10℃ to completely remove wax and residual trace solid impurities, thereby obtaining dewaxed oil.

4. The method for refining unsaturated oils based on enzyme-molecule coupling according to claim 1, characterized in that, In step S3, the adsorption medium is a composite material modified by surface oleophilic-hydrophobic balance, which is a food-grade silica gel and a synthetic zeolite composite with a specific pore size, or a mixture of mesoporous activated carbon and an inert polymer carrier.

5. The method for refining unsaturated oils based on enzyme-molecule coupling according to claim 1, characterized in that, Step S4 includes: Step S401: First, use a packed tower or plate tower to perform short-time low-temperature deodorization on the purified oil; Step S402: Then, the purified oil is rapidly heated to 120-130℃ under an absolute pressure ≤300Pa, and food-grade superheated steam that has been deoxygenated is introduced as a stripping agent. The amount of steam used is 0.3-1.0% of the oil weight. The deodorization temperature is strictly ≤130℃ and the residence time is ≤30 minutes. In step S403, the deodorized oil is rapidly cooled to below 60°C using a plate heat exchanger to obtain refined oil.

6. The method for refining unsaturated oils based on enzyme-molecule coupling according to claim 1, characterized in that, In step S5, the natural antioxidant system includes: Primary antioxidant: 0.03-0.08% mixed tocopherol concentrate; Synergists and metal chelating agents: 0.005-0.02% phospholipids; Co-antioxidant: 0.01-0.04% rosemary extract, rich in carrageenan and carrageenanol.

7. A refining apparatus for unsaturated oils based on enzyme-product coupling, characterized in that, include: Enzymatic degumming and deacidification system: includes a heater for heating crude oil, an enzyme reaction vessel for containing crude oil for enzymatic reaction, and a membrane filter for filtering crude oil after enzymatic reaction. A dynamic crystallization dewaxing system coupled with ultrasound includes a crystallization tank for cooling and containing clear oil crystals, an ultrasonic generator for applying ultrasound to the crystallization tank, and a rotary drum filter for filtering the crystallized clear oil. Adsorption purification and odor precursor removal system: including a heat exchanger for heating dewaxed oil and an adsorption column for purifying and adsorbing tractors; Low-temperature stripping deodorization and final purification system: including a low-temperature deodorization tower for deodorizing purified oil at low temperature, a heater for heating the deodorized oil after low-temperature deodorization, a stripping tower for stripping the deodorized oil, and a cooler for cooling the stripped oil. Natural antioxidant network construction system: including blending tanks for containing the mixture of refined oil and natural antioxidant system and terminal filters for filtering the mixed oil.

8. The unsaturated oil refining apparatus based on enzyme-product coupling according to claim 7, characterized in that, The drum filter includes: A rack, on which a machine compartment is provided; The filter cartridge is rotatably connected inside the machine compartment and is driven to rotate by a power component located on the frame. The filter cartridge is equipped with filter cloth. The negative pressure chamber is located on one side of the filter cartridge and is connected to a negative pressure nitrogen pipeline. The injection chamber is located at the top of the filter cartridge and is connected to a nitrogen injection pipe; The collection tank is located directly below the blow chamber and is connected to a negative pressure suction pipe.

9. The unsaturated oil refining apparatus based on enzyme-product coupling according to claim 8, characterized in that, The drum filter also includes: The heat-insulating jet pipe is located on the outside of the filter cylinder on the side away from the negative pressure chamber, and the heat-insulating jet pipe is provided with several nozzles facing the filter cylinder. A collection hood is positioned opposite the heat-insulating spray pipe and located inside the filter cylinder. The collection hood is connected to a negative pressure suction pipe.

10. An unsaturated oil refining apparatus based on enzyme coupling according to claim 8 or 9, characterized in that, A gap is formed between the two sides of the collection tank and the filter cloth, and an adjustment component is provided inside the machine compartment to seal the gap. The adjustment component includes: A receiving box, wherein a wedge block is slidably connected to the inside of the receiving box along the radial direction of the filter cylinder, and a spring is provided between the wedge block and the bottom surface of the receiving box; The slider is slidably connected to the collection tank along the radial direction of the filter cylinder, with one end of the slider facing the inner wall of the filter cylinder and equipped with a sealing plate; A connecting rod, wherein both ends of the connecting rod are respectively provided with connecting posts that are connected to the wedge and the slider; The filter cylinder is provided with a baffle that can compress the wedge.

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