A method for pretreating rapeseed and efficiently extracting oil therefrom

Abstract

The application discloses a kind of pretreatment rapeseed and its high-efficiency oil extraction method, belong to agricultural product processing and oil extraction technical field.The method aims at solving the problems of low value of rapeseed meal, lignin is difficult to use and the efficiency of oil extraction is limited in traditional rapeseed oil production process.The method comprises the following steps: constructing functional ternary eutectic solvent (F-TDES) containing choline chloride, citric acid, L-serine and ferric chloride hexahydrate, combining with pulse electric field (PEF) to induce cell poration, and carrying out immersion reaction within a limited time window, to realize efficient oil extraction and in-situ synthesis of lignin-iron nanoscale enzyme in rapeseed meal simultaneously.Through the above scheme, the application completes "physical wall breaking-chemical depolymerization-in-situ self-assembly" in a single process, significantly improves the oil yield and the level of high value of by-products.

Description

Technical Field

[0001] This invention belongs to the field of agricultural product processing and oil extraction technology, specifically, it relates to a method for pre-treating rapeseed and extracting its oil efficiently. Background Technology

[0002] Rapeseed, as an important oilseed crop in my country, holds an irreplaceable strategic position in ensuring edible oil security and feed protein supply. Traditional rapeseed oil extraction processes primarily focus on the efficient extraction of oil, while the byproduct—rapeseed meal, which accounts for approximately 55%-60% of the raw material's mass—is generally utilized for low-value purposes, primarily as ruminant animal feed or organic fertilizer. The structural potential and functional value of its intrinsic high-molecular-weight components have long been neglected. In recent years, with the deepening of biorefining concepts and the development of green chemistry technologies, how to achieve high-value synergistic conversion of all rapeseed components while ensuring oil extraction efficiency has become an important research direction in the interdisciplinary field of oil engineering and biomass refining.

[0003] Against this backdrop, novel extraction technologies, such as pulsed electric field (PEF) coupled with deep eutectic solvent (DES), have gradually attracted attention. Existing technologies employ PEF pretreatment combined with DES extraction of oils. The core idea is to disrupt cells using PEF, thereby enhancing the penetration and dissolution of intracellular oils by DES. This technology, to a certain extent, overcomes the limitations of traditional hot pressing or organic solvent extraction in terms of energy consumption, safety, and environmental impact, embodying the process logic of "physical cell disruption + green solvent leaching," and demonstrating certain advantages in improving oil yield.

[0004] However, with the continuous development of related technologies and the increasingly stringent requirements for resource utilization efficiency in application scenarios, some inherent characteristics of the aforementioned technical solutions at the principle level have gradually revealed deep-seated limitations in addressing new challenges. Specifically, the existing DES system is designed only to serve as an "inert extraction medium," and its chemical composition has not been functionalized to suit the complex supramolecular structure of rapeseed—especially the dense lignin-carbohydrate complex (LCC) contained in the seed coat. Due to its highly cross-linked phenolic-carbohydrate covalent bond structure, the LCC network is extremely difficult to dissociate under normal mild conditions, resulting in a large amount of lignin being encapsulated within the oil meal, hindering the complete release of oil and making it difficult to be effectively activated and utilized. More importantly, the existing process completely ignores the enormous potential of lignin as a natural aromatic polymer in high-value-added functional materials such as catalysis, sensing, and adsorption. Correspondingly, although the components in DES (such as choline chloride and organic acids) have a certain hydrogen bond donor and acceptor capacity, they lack the chemical driving force for directional shearing, stable dispersion and in-situ functionalization of lignin. As a result, the entire process still remains in the linear thinking mode of "oil extraction is the end point", and fails to build an intrinsic coupling mechanism between oil extraction and high-value utilization of by-products.

[0005] The reason for this lies in the fact that existing technologies treat physical cell disruption and chemical extraction as two independent processes, neglecting their synergistic window in the spatiotemporal dimensions. PEF-induced cell perforation is transient and reversible. If a reactive solvent system is not rapidly introduced before the pores close, not only is the oil extraction efficiency limited, but the crucial opportunity to utilize open channels for in-situ modification of intracellular macromolecules is also missed. Furthermore, even if some lignin is released, without suitable metal ions or ligands to guide its self-assembly, it is difficult to form nanostructures with clear catalytic activity. Currently, no technology can cleverly utilize the multiple functions of DES components—serving as both an oil extraction medium and a lignin depolymerizing agent and nanozyme building block—to simultaneously achieve efficient oil recovery and in-situ synthesis of lignin-based functional materials in a single reaction system. This separation of "extraction" and "creation" functions not only results in a huge waste of biomass resources but also hinders the transformation and upgrading of the rapeseed processing industry towards high-value, refined, and integrated directions.

[0006] Therefore, how to construct a multifunctional solvent system that combines physical perforation responsiveness, chemical depolymerization selectivity, and in-situ self-assembly capability, and how to achieve the simultaneous directional shearing of lignin and in-situ construction of functional nanozymes during oil extraction by precisely controlling the process sequence, has become a key challenge and an urgent technical problem for those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a method for pre-treating rapeseed and extracting its oil efficiently. By constructing a ternary eutectic solvent system with multiple functions and combining it with the cell perforation effect induced by a pulsed electric field, the method simultaneously achieves efficient oil extraction and in-situ construction of peroxidase-like active nanocatalytic materials in rapeseed meal by-products in a single reaction process. This breaks through the linear mode of "oil extraction is the endpoint" in traditional rapeseed processing technology and establishes an intrinsic coupling mechanism between oil extraction and the synthesis of high-value functional materials.

[0008] To achieve the above-mentioned objectives, this invention provides a method for pre-treating rapeseed and extracting its efficient oil, comprising the following steps:

[0009] (1) Adjust the moisture content of rapeseed to 7.0-9.0 wt% to obtain pretreated rapeseed.

[0010] Within this range, water content can enhance the dielectric response of cell membranes and improve PEF perforation efficiency; at the same time, adequate water content helps maintain the ionic conductivity of F-TDES and promotes reaction kinetics.

[0011] (2) The pretreated rapeseed is subjected to pulsed electric field treatment by applying a unipolar square wave pulse with a pulse width of 20 μs, a pulse frequency of 100 Hz, and an electric field strength of 1.5-2.2 kV / cm.

[0012] The electric field strength range can induce the formation of solvent-permeable nanopores on the rapeseed cell membrane, while avoiding cell wall rupture or leakage of contents. Furthermore, this perforation process does not damage the overall cell structure, only creating temporarily open hydrophilic channels within the lipid bilayer, providing a physical pathway for subsequent rapid solvent molecule penetration.

[0013] (3) Within 60 seconds after the pulsed electric field treatment ends, the pretreated rapeseed is transferred to a preheated functional ternary eutectic solvent F-TDES, wherein the F-TDES is composed of choline chloride, citric acid, L-serine, and ferric chloride hexahydrate, wherein the molar ratio of choline chloride, citric acid, and L-serine is 1:1.0-1.8:0.6-1.0, and the mass of ferric chloride hexahydrate accounts for 1.0-2.0 wt% of the total mass of F-TDES. This range of ferric chloride hexahydrate mass percentage ensures... Concentration can drive the full coordination and self-assembly of lignin fragments, while avoiding non-specific aggregation or catalytic side reactions caused by excessive metal ions.

[0014] The 60-second time window ensures that solvent injection is completed before the cell membrane perforation channels close, thereby maximizing the solvent's contact efficiency with intracellular lipids and LCCs.

[0015] In the functional ternary eutectic solvent F-TDES, choline chloride acts as a hydrogen bond acceptor, and citric acid acts as the main hydrogen bond donor, together forming the basic framework of the eutectic solvent; L-serine acts as a second hydrogen bond donor and also as a functionalizing component, and the amino and carboxyl groups in its molecular structure endow it with the ability to bind hydrogen bonds in the LCC network. The selective nucleophilic attack capability of ether bonds enables directional cleavage of lignin fragments; ferric chloride hexahydrate serves as a metal precursor, its Ions act as coordination centers in the reaction system, coordinating with functional groups such as phenolic hydroxyl and carboxyl groups in the lignin fragments released by shearing, driving the self-assembly of the nanocomposite.

[0016] (4) The reaction was carried out at 60-70℃ with a solid-liquid ratio of 1 g:10 mL and a reaction time of 2 hours. The transient nanochannels formed by PEF were used to cleave the L-serine lignin-carbohydrate complex LCC structure and induce Fe 3+ The released lignin fragments self-assemble in situ, simultaneously achieving oil extraction and in situ synthesis of lignin-iron nanozymes.

[0017] During the reaction, the L-serine molecule in F-TDES selectively cleaves the LCC via a nucleophilic substitution reaction. Linking bonds releases low-molecular-weight lignin fragments; simultaneously... Ions coordinate with the polydentate ligand functional groups in these lignin fragments to form complexes. A coordination polymer with lignin as the ligand is formed at the center; the coordination polymer further self-assembles into a lignin-iron nanocomposite with peroxidase-like activity on the surface of rapeseed meal through the interfacial confinement effect induced by solvent evaporation.

[0018] (5) After the reaction is completed, three-phase separation is performed to obtain high-purity rapeseed oil and functionalized rapeseed meal loaded with lignin-iron nanoenzymes.

[0019] The F-TDES has in-situ depolymerization-coordination function, serving not only as an oil extraction medium but also as a lignin depolymerization agent and nanoenzyme building unit, enabling the efficient recovery of oils and the in-situ synthesis of lignin-based functional materials in a single reaction system.

[0020] At the reaction mechanism level, the directional cleavage of L-serine by LCC follows a nucleophilic substitution mechanism. In LCC... The α-amino group of L-serine is the main linking mechanism between lignin and hemicellulose, exhibiting high chemical stability. The α-amino group in L-serine molecules has a low degree of protonation in weakly acidic environments, retaining strong nucleophilicity and allowing it to attack... In the key The bond at the position is broken, generating a phenylpropane unit fragment. Subsequently, the released lignin fragment passes through its phenolic hydroxyl group ( )and Coordination occurs, forming stable five- or six-membered chelate rings, which further aggregate under interfacial confinement conditions to form lignin-iron nanocomposites exhibiting peroxidase-like activity. In TMB- In colorimetric systems, the catalytic mechanism may involve / The redox cycle and the production of reactive oxygen species share a similar mechanism with the catalytic pathway of natural horseradish peroxidase (HRP).

[0021] Furthermore, the molar ratio of choline chloride, citric acid, and L-serine in the F-TDES is 1:1.5:0.8, and the mass of ferric chloride hexahydrate accounts for 1.5 wt% of the total mass of the F-TDES.

[0022] Further, in step (3), the pretreated rapeseed is transferred to a preheated functional ternary eutectic solvent F-TDES within 10-30 seconds after the pulsed electric field treatment ends.

[0023] Furthermore, in step (1), the moisture content of the rapeseed is adjusted to 8.5 wt%.

[0024] Furthermore, the electric field strength in step (2) is 1.8 kV / cm.

[0025] Furthermore, the reaction temperature in step (4) is 65°C.

[0026] Furthermore, the F-TDES provides a weakly acidic environment to promote the nucleophilic reaction of L-serine.

[0027] Further, the preparation method of F-TDES in step (3) is as follows: choline chloride, citric acid, L-serine and ferric chloride hexahydrate are mixed and stirred at 300 rpm for 2 hours at 70°C.

[0028] Furthermore, in step (5), three-phase separation is achieved by centrifugation. Centrifugation at 8000 rpm for 15 minutes yields a light yellow transparent oil phase in the upper layer, a dark brown F-TDES mother liquor that can be recycled, and a brown-black functionalized rapeseed meal in the lower layer.

[0029] Furthermore, the functionalized rapeseed meal was obtained by washing with deionized water and then vacuum drying at 40°C for 24 hours.

[0030] Beneficial effects:

[0031] This invention constructs a multifunctional ternary eutectic solvent system and combines it with the cell perforation effect induced by a pulsed electric field to simultaneously achieve efficient oil extraction and in-situ construction of peroxidase-like active nanocatalysts in rapeseed meal, a byproduct, within a single reaction process. Compared with traditional processes, this invention has the following significant advantages:

[0032] (1) By strictly controlling the transfer time window within 60 seconds after PEF treatment, F-TDES is ensured to fully penetrate before the cell membrane pores close, and the oil extraction rate is increased to over 91%, which is significantly better than the existing technology;

[0033] (2) The ternary F-TDES system has a synergistic removal effect on glucosinolate antinutritional factors, reducing the residual amount of glucosinolates to below 10 μmol / g;

[0034] (3) It realizes the high-value utilization of rapeseed meal and transforms low-value by-products into nanomaterials with catalytic functions;

[0035] (4) An intrinsic coupling mechanism between oil extraction and functional material synthesis was established, breaking through the traditional linear model of "oil extraction is the endpoint" and providing a new approach for the high-value synergistic transformation of all rapeseed components. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions of this invention, the present application will be further described in detail below with reference to embodiments.

[0037] Example 1

[0038] 1. Preparation of functional ternary eutectic solvent (F-TDES)

[0039] (1) Raw material weighing: Accurately weigh 13.96 g of choline chloride (ChCl, molecular weight 139.62 g / mol), 28.82 g of citric acid (CA, molecular weight 192.123 g / mol), 8.41 g of L-serine (Ser, molecular weight 105.09 g / mol), and ferric chloride hexahydrate ( (Molecular weight 270.30 g / mol) 0.78 g. The molar ratio of the above components is ChCl:CA:Ser = 1:1.5:0.8. The mass of the solvent accounts for 1.5 wt% of the total solvent system mass.

[0040] (2) Mixing and reaction: The weighed solid components were added sequentially to a 250 mL three-necked flask. The flask was placed on a constant temperature magnetic stirrer and stirred continuously at 300 rpm for 2 hours at 70°C.

[0041] After the reaction is complete, a homogeneous, transparent, and precipitate-free pale yellow viscous liquid is obtained, which is the F-TDES described in this invention. This temperature (70°C) is lower than the decomposition temperature of each component, and is sufficient to overcome the formation energy barrier of the hydrogen bond network, ensuring the occurrence of eutectic phenomena.

[0042] 2. Rapeseed raw material pretreatment

[0043] The raw material used was rapeseed (Brassica napus L.), with an initial moisture content of approximately 10.2 wt%. To meet the requirements of subsequent PEF treatment, the moisture content needed to be precisely controlled to 7.0-9.0 wt%. The specific procedure was as follows: the rapeseed was spread evenly in a stainless steel tray and placed in a constant temperature and humidity chamber at 25°C and 55% relative humidity for 48 hours to equilibrate. Moisture content analysis revealed a final moisture content of 8.5 wt%. This moisture content level ensured that the cell membrane maintained good dielectric response under PEF to form effective pores, while also preventing excessive dilution of F-TDES due to high moisture content, which would reduce its ionic strength and reactivity.

[0044] 3. Pulsed electric field (PEF) induced perforation treatment

[0045] The rapeseed grains, after moisture content control, were loaded into a PEF treatment chamber. Parallel plate electrodes with a spacing of 2 cm were placed inside the chamber. A unipolar square wave pulse was applied with the following parameters: pulse width 20 μs, pulse frequency 100 Hz, total pulse count 500, corresponding to a total treatment time of 10 seconds, and an electric field strength of 1.8 kV / cm. Under these conditions, the rapeseed cell membrane lipid bilayer underwent electroporation under the instantaneous high-voltage electric field. Notably, this perforation process only affected the cell membrane structure and did not disrupt the cell wall integrity, thus maintaining the overall morphology of the rapeseed grains and preventing non-selective leakage of contents.

[0046] 4. Spatiotemporal coordinated response and in-situ synthesis reaction

[0047] This step is crucial to achieving "oil extraction and creation," and its core lies in strictly controlling the time interval between the end of PEF treatment and the start of F-TDES impregnation.

[0048] (1) Time window control: After the PEF treatment is completed, start the timer immediately and transfer all rapeseed grains to F-TDES preheated to 65℃ within 10s.

[0049] (2) Reaction conditions: The solid-liquid ratio is 1 g: 10 mL. The reaction is carried out in a closed reaction vessel and stirred at 200 rpm for 2 hours at 65°C.

[0050] (3) Chemical mechanism:

[0051] 1) LCC directed shearing: The α-amino group of the L-serine molecule in F-TDES is partially protonated in the weakly acidic environment (pH ≈ 3.2) provided by citric acid, but still retains sufficient nucleophilicity to selectively attack the LCC structure. ether bond The carbon atom triggers a nucleophilic substitution reaction, breaking the covalent bond between lignin and hemicellulose and releasing free low-molecular-weight lignin fragments.

[0052] 2) In-situ self-assembly: The released lignin fragments are rich in phenolic hydroxyl groups, acting as polydentate ligands with F-TDES. Coordination complexes are formed, creating a stable iron-lignin coordination complex. This complex undergoes confined self-assembly on the surface of rapeseed meal particles, forming a nanocatalytic material with peroxidase-like activity.

[0053] 5. Three-phase separation and product acquisition

[0054] After the reaction was complete, the reaction mixture was cooled to room temperature and transferred to 50 mL centrifuge tubes, then centrifuged at 8000 rpm for 15 minutes. Due to density differences, the system naturally separated into three layers:

[0055] (1) Upper layer: pale yellow transparent oil phase, which is high-purity rapeseed oil.

[0056] (2) Intermediate layer: dark brown F-TDES mother liquor, which can be recycled.

[0057] (3) Lower layer: brownish-black solid residue, which is functionalized rapeseed meal loaded with lignin-iron nanoenzymes.

[0058] Each phase was collected separately. Rapeseed oil was dehydrated with anhydrous sodium sulfate and used for subsequent quality analysis; functionalized rapeseed meal was washed three times with deionized water to remove residual solvent, and then vacuum dried at 40°C for 24 hours to obtain the final product.

[0059] Example 2

[0060] This embodiment is basically the same as Embodiment 1, except that the following parameters are adjusted:

[0061] 1. The molar ratio of choline chloride, citric acid, and L-serine was adjusted to ChCl:CA:Ser = 1:1.2:0.6. The addition amount was adjusted to 1.0 wt%.

[0062] 2. The final moisture content of the rapeseed raw material was adjusted to 7.0 wt%.

[0063] 3. The electric field strength of the pulsed electric field is adjusted to 1.5 kV / cm.

[0064] 4. Time window control: After the PEF treatment is completed, start the timer immediately and transfer all rapeseed grains to the F-TDES preheated to 60℃ within 30 seconds.

[0065] Example 3

[0066] This embodiment is basically the same as Embodiment 1, except that the following parameters are adjusted:

[0067] 1. The molar ratio of choline chloride, citric acid, and L-serine was adjusted to ChCl:CA:Ser = 1:1.8:1.0. The addition amount was adjusted to 2.0 wt%.

[0068] 2. The final moisture content of the rapeseed raw material was adjusted to 9.0 wt%.

[0069] 3. The electric field strength of the pulsed electric field is adjusted to 2.2 kV / cm.

[0070] 4. Time window control: After the PEF treatment is completed, start the timer immediately and transfer all rapeseed grains to the F-TDES preheated to 70℃ within 60 seconds.

[0071] Comparative Example 1

[0072] This comparative example is identical to Example 1 except that L-serine is not added when preparing the functional ternary eutectic solvent (F-TDES).

[0073] Comparative Example 2

[0074] This comparative example only excludes the addition of functional ternary eutectic solvents (F-TDES). All other conditions and operations are the same as in Example 1.

[0075] Comparative Example 3

[0076] This comparative example only adjusts the time window control of step 4, (1) in Example 1 from 10s to 90s, while the other conditions and operations are the same as in Example 1.

[0077] Comparative Example 4

[0078] This comparative example uses a binary DES with ChCl:CA = 1:2 instead of the functional ternary eutectic solvent (F-TDES) in Example 1, while all other conditions and operations are the same as in Example 1.

[0079] Data Analysis and Comparison

[0080] To objectively evaluate the technical effects of the present invention, the oil extraction rate, glucosinolate residue in the extracted oil, and nanoenzyme activity of the functionalized rapeseed meal in Examples 1-3 and Comparative Examples 1-4 were quantitatively tested, as follows:

[0081] (1) Oil extraction rate

[0082] Soxhlet extraction was used as the control standard, and the calculation formula was as follows: .in, The actual rapeseed oil mass (g) obtained by the process of Examples 1-3 or Comparative Examples 1-4. The total mass (g) of rapeseed raw materials input into the reaction; The total oil content (%) of the rapeseed raw material was determined by Soxhlet extraction of the raw rapeseed with petroleum ether for 6 hours.

[0083] (2) Extraction of glucosinolate residues in oils

[0084] Take 1g of extracted rapeseed oil and add 5mL of 70% methanol solution for extraction. Perform on-column desulfurization with desulfurizing enzyme, and collect the desulfurized glucosinolate eluent. Use a C18 reversed-phase column with acetonitrile and water as the mobile phase for gradient elution, and a detection wavelength of 229 nm. Calculate the total glucosinolate residue in the oil using the internal standard method (internal standard: benzylthioglycoside), in units of... express.

[0085] (3) Nanoenzyme activity of functionalized rapeseed meal

[0086] Take 10 mg of dried functionalized rapeseed meal, add 5 mL of 0.2 M acetate-sodium acetate buffer (pH 4.0), and then add 100 mg of [unspecified substance] sequentially. 0.1 MtMB ethanol solution and 100 3% Solution. Place the mixture in a 37°C constant temperature water bath and react for 10 minutes in the dark. After the reaction is complete, take the supernatant and measure its absorbance at 652 nm using a UV-Vis spectrophotometer. The higher the absorbance value, the stronger the catalytic activity of the nanozyme.

[0087] Table 1

[0088]

[0089] As shown in Table 1, Examples 1-3 all achieved oil extraction rates higher than 91%, significantly better than Comparative Examples 1, 3, and 4 (all below 82%). Particularly noteworthy is that the residual glucosinolates in the Example groups were all below 10 μmol / g, while those in the Comparative Examples were generally above 13 μmol / g, indicating that the F-TDES system has a synergistic removal effect on glucosinolate anti-nutritional factors. Regarding catalytic activity, Examples 1-3... The values ​​were all greater than 1.5, indicating that the functional meal had strong peroxidase activity.

[0090] Compared to Example 1, Comparative Example 1 lacked only the L-serine component, but its oil extraction rate was only 76.2%, far lower than the 93.5% of Example 1; the glucosinolate residue was as high as 15.6 μmol / g; more importantly, The value was only 0.21, indicating almost no catalytic activity. This result reveals multiple key roles of L-serine in this process: First, the α-amino group of L-serine exhibits moderate nucleophilicity in a weakly acidic environment, enabling it to selectively attack the C group in the LCC structure. β -O-C4 ether bond C β The introduction of L-serine allows for the directional breaking of the covalent bonds between lignin and hemicellulose at the carbon atom position. Secondly, it alters the hydrogen bond network structure of DES, enhancing the solvent's penetration into the rapeseed cell wall. Thirdly, the small molecular fragments produced by L-serine decomposition can react with glucosinolates, promoting their separation from the oil. The lack of L-serine prevents the effective dissociation of the LCC network, hindering not only the complete release of oil but also making it difficult to activate and utilize lignin, thus limiting the traditional "oil extraction as the endpoint" process.

[0091] Comparative Example 2 differs from Example 1 only in that it lacks... Its oil extraction rate (89.4%) is similar to that of Example 1 (93.5%), indicating that... It has little impact on the oil extraction process; however, its The value was only 0.05, indicating a near loss of catalytic activity. This fully demonstrates... In this invention, it is not used as a simple metal additive, but as the core coordination center for the construction of nanozymes. The released lignin fragments are rich in phenolic hydroxyl groups, acting as polydentate ligands with... Coordination complexes form, creating iron-lignin coordination complexes with peroxidase-like activity. (No further information provided.) The presence of lignin means that although some of it may be released, it cannot form nanostructures with clear catalytic activity, causing the "creation" function to fail and the entire process to degenerate into a simple oil extraction process.

[0092] Compared to Example 1, Comparative Example 3 only extended the time window from 10 s to 90 s, resulting in a decrease in oil extraction rate from 93.5% to 81.3% and an increase in glucosinolate residue from 7.9 μmol / g to 13.2 μmol / g. The value dropped significantly from 1.93 to 0.68. This significant difference reveals the core value of the "spatiotemporal synergy" concept in this invention: PEF-induced cell membrane perforation is transient and reversible, typically beginning to close within seconds to tens of seconds. Transferring to F-TDES within a 10-second time window fully utilizes the open nanochannels, allowing F-TDES to rapidly penetrate into the cell interior, not only improving lipid extraction efficiency but also enabling the release of L-serine and... It can promptly contact and react with intracellular macromolecules. However, after 60 seconds, the cell membrane pores gradually close, making it difficult for F-TDES to fully penetrate, resulting in incomplete LCC depolymerization and reduced lignin release, which in turn affects the in-situ synthesis efficiency of nanozymes.

[0093] Comparative Example 4 used a conventional ChCl:CA=1:2 binary DES instead of the F-TDES of this invention, and its oil extraction rate (78.9%) and catalytic activity ( =0.08) were significantly lower than those in Example 1. This indicates that although binary DES has a certain extraction ability, it lacks the directional cleavage function of L-serine on LCC and The coordination function of the lignin is insufficient to effectively dissociate the lignin-carbohydrate complex network under mild conditions. More importantly, the binary DES system lacks a mechanism for metal ion-guided lignin self-assembly, preventing the released lignin fragments from forming nanocatalysts with specific functions. This results in the entire process failing to achieve the integrated design goal of "oil extraction and material creation".

[0094] In summary, this invention, by constructing a multifunctional ternary eutectic solvent system (F-TDES) and combining it with the cell perforation effect induced by a pulsed electric field, simultaneously achieves efficient oil extraction and in-situ construction of lignin-based nanozymes in a single reaction process. The introduction of L-serine solves the technical problem of the difficulty in dissociating the LCC network. The coordination of lignin enables its functionalization, while the strictly controlled 60-second time window ensures the spatiotemporal synergy between physical cell wall disruption and chemical transformation. This technical solution breaks through the linear model of "oil extraction as the endpoint" in traditional rapeseed processing, establishing an intrinsic coupling mechanism between oil extraction and the synthesis of high-value functional materials. It not only significantly improves the oil extraction rate (>91%) and reduces glucosinolate residues (<10 μmol / g), but also endows rapeseed meal with novel catalytic functional value. >1.5), providing a solution for the high-value utilization of all components of rapeseed. Experimental data fully demonstrate that the F-TDES system and its process conditions described in this invention are necessary and sufficient conditions for achieving the technical goal of "oil extraction as product creation," and there is a significant synergistic effect among the components, none of which can be omitted.

Claims

1. A method for pre-treating rapeseed and extracting its high-efficiency oil, characterized in that, Includes the following steps: (1) Adjust the moisture content of rapeseed to 7.0-9.0 wt% to obtain pretreated rapeseed; (2) The pretreated rapeseed is subjected to pulsed electric field treatment by applying a unipolar square wave pulse with a pulse width of 20 μs, a pulse frequency of 100 Hz, and an electric field strength of 1.5-2.2 kV / cm. (3) Within 60 seconds after the pulsed electric field treatment ends, the pretreated rapeseed is transferred to a preheated functional ternary eutectic solvent F-TDES, wherein the F-TDES is composed of choline chloride, citric acid, L-serine and ferric chloride hexahydrate, wherein the molar ratio of choline chloride, citric acid and L-serine is 1:1.0-1.8:0.6-1.0, and the mass of ferric chloride hexahydrate accounts for 1.0-2.0 wt% of the total mass of F-TDES. (4) The reaction is carried out at 60-70℃ with a solid-liquid ratio of 1 g:10 mL and a reaction time of 2 hours; (5) After the reaction is completed, three-phase separation is performed to obtain high-purity rapeseed oil and functionalized rapeseed meal loaded with lignin-iron nanoenzyme; The F-TDES has in-situ depolymerization-coordination function, serving not only as an oil extraction medium but also as a lignin depolymerization agent and nanoenzyme building unit, enabling the efficient recovery of oils and the in-situ synthesis of lignin-based functional materials in a single reaction system.

2. The method according to claim 1, characterized in that, The molar ratio of choline chloride, citric acid, and L-serine in the F-TDES is 1:1.5:0.8, and the mass of ferric chloride hexahydrate accounts for 1.5 wt% of the total mass of the F-TDES.

3. The method according to claim 1 or 2, characterized in that, In step (3), the pretreated rapeseed is transferred to a preheated functional ternary eutectic solvent F-TDES within 10-30 seconds after the pulsed electric field treatment ends.

4. The method according to claim 1, characterized in that, In step (1), the moisture content of the rapeseed is adjusted to 8.5 wt%.

5. The method according to claim 1, characterized in that, The electric field strength in step (2) is 1.8 kV / cm.

6. The method according to claim 1, characterized in that, The reaction temperature in step (4) is 65℃.

7. The method according to claim 1, characterized in that, The F-TDES provide a weakly acidic environment to promote the nucleophilic reaction of L-serine.

8. The method according to claim 1, characterized in that, The preparation method of F-TDES in step (3) is as follows: choline chloride, citric acid, L-serine and ferric chloride hexahydrate are mixed and stirred at 300 rpm for 2 hours at 70°C.

9. The method according to claim 1, characterized in that, In step (5), three-phase separation is achieved by centrifugation. Centrifugation at 8000 rpm for 15 minutes yields a light yellow transparent oil phase in the upper layer, a dark brown F-TDES mother liquor that can be recycled, and a brown-black functionalized rapeseed meal in the lower layer.

10. The method according to claim 9, characterized in that, The functionalized rapeseed meal was obtained by washing with deionized water and then vacuum drying at 40°C for 24 hours.

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