Paeonia suffruticosa seed oil and beta-lactoglobulin combined compound and preparation method thereof

Abstract

The invention discloses a peony seed oil and beta-lactoglobulin combined compound and a preparation method thereof, and the peony seed oil and beta-lactoglobulin combined compound comprises the following components by mass: 5%-15% of peony seed oil, 3% of beta-lactoglobulin, 0.1%-1% of a composite antioxidant system, 0.1%-0.5% of lecithin, 0.5%-2% of prebiotics, and the balance purified water; the compound antioxidant system is prepared from the following components in percentage by weight: 0.05 to 0.3 percent of vitamin E and 0.05 to 0.7 percent of rosemary extract. The prepared peony seed oil and beta-lactoglobulin combined compound shows excellent oxidation resistance, double protection barriers are formed inside and outside the nanocapsule through a designed composite oxidation resistance system, the oxidation process of the compound is effectively delayed, and by adopting a micro-emulsification-nano embedding technology, the stability of the compound is improved, and the stability of the compound is improved. According to the invention, multi-stage protection of the active components is realized, and the storage stability of the compound is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of peony seed oil research and application technology, and in particular to a complex of peony seed oil and β-lactoglobulin and its preparation method. Background Technology

[0002] Peony seed oil, a precious woody nut oil, is rich in α-linolenic acid and other polyunsaturated fatty acids, exhibiting significant antioxidant, anti-inflammatory, and cardiovascular protective effects. However, peony seed oil is prone to oxidation and deterioration, and its direct addition to food can lead to problems such as greasy taste and uneven dispersion. Traditional methods have attempted to combine peony seed oil with lactoferrin or ovalbumin, but these methods suffer from poor stability and insufficient antioxidant properties, failing to meet the demands of the modern food industry for high-quality, highly stable complexes. Therefore, this application provides a complex of peony seed oil and β-lactoglobulin, and its preparation method, to meet these requirements. Summary of the Invention

[0003] The purpose of this application is to provide a complex of peony seed oil and β-lactoglobulin and its preparation method, in order to solve the technical problems of poor stability and insufficient antioxidant properties in the traditional combination of peony seed oil and β-lactoglobulin.

[0004] To achieve the above objectives, this application provides the following technical solution: a complex of peony seed oil and β-lactoglobulin, comprising the following components by mass percentage:

[0005] Peony seed oil 5%~15%, β-lactoglobulin 3%, complex antioxidant system 0.1%~1%, lecithin 0.1%~0.5%, prebiotics 0.5%~2%, the remainder is purified water;

[0006] The compound antioxidant system contains 0.1% to 1% vitamin E (0.05% to 0.3%) and rosemary extract (0.05% to 0.7%).

[0007] A method for preparing a complex of peony seed oil and β-lactoglobulin, comprising the following steps;

[0008] S1. Preparation of microemulsion-nano-encapsulated composite emulsion

[0009] S11. Peony seed oil and A2β-lactoglobulin solution are mixed in a certain ratio, and lecithin is added as a co-emulsifier. A crude emulsion is formed by using a high-speed shearing machine.

[0010] S12. Microemulsification treatment: The crude emulsion is microemulsified by a homogenizer to reduce the droplet size distribution D50 to the range of 0.2-0.5μm;

[0011] S13, Implementation of Nano-Encapsulation Technology

[0012] S131, Wall material preparation: Sodium octenyl succinate starch and chitosan are dissolved in an aqueous phase to form a positively charged nano-embedded wall material solution.

[0013] S132, Composite Coagulation: The microemulsion is slowly added dropwise to the wall material solution, and the pH is adjusted to 4.5 to induce electrostatic composite coagulation, forming nanocapsules with an average particle size of 80-120 nm.

[0014] S133, Curing treatment, adding glutaraldehyde for brief cross-linking, followed by dialysis to remove residual cross-linking agent;

[0015] S2. Addition of compound antioxidants: Appropriate amounts of vitamin E and rosemary extract are added simultaneously to the nano-embedded emulsion. Uniform dispersion is achieved through vortex mixing, and the entire mixing process is carried out under nitrogen protection to control the dissolved oxygen content ≤0.2 mg / L.

[0016] S3, pH adjustment and sterilization

[0017] S31. Isoelectric point adjustment: The pH of the emulsion was precisely adjusted to 6.8±0.1 using a citrate / disodium hydrogen phosphate buffer solution, so that the β-lactoglobulin ζ potential reached -5.2 mV.

[0018] S32. Mild sterilization: Pasteurization combined with pulsed light treatment is used to ensure that the total number of colonies is ≤10 CFU / g, while the α-linolenic acid retention rate is ≥92%.

[0019] S4. Nitrogen-filled packaging: The sterilized emulsion is filled into multi-layer co-extruded aluminum foil bags, and nitrogen is used to replace the oxygen residue until it is ≤0.3%, ensuring that the heat seal strength is ≥30 N / 15mm.

[0020] In a preferred embodiment of this invention, raw material pretreatment is performed between steps S1, including the following steps:

[0021] S10: Peony Seed Oil Refining: Selected peony seed oil with α-linolenic acid content ≥40% is subjected to low-temperature dewaxing, activated clay adsorption decolorization and molecular distillation treatment in sequence to ensure peroxide value ≤2.0 meq / kg;

[0022] S20: β-lactoglobulin purification: β-lactoglobulin was extracted by chromatographic separation technology, concentrated by ultrafiltration, freeze-dried and reconstituted to a concentration of 2%, and pre-emulsified by adjusting the pH to 7.0.

[0023] As a preferred embodiment of this example, in step S21, a homogenizer is used for two-step homogenization: a first high-pressure homogenization controlled at 20 MPa, and a second low-pressure homogenization controlled at 5 MPa.

[0024] In a preferred embodiment of this invention, during step S11, while the high-speed shearing machine is forming the crude emulsion, an ultrasonic generator is simultaneously activated to perform ultrasonic treatment on the mixture. The ultrasonic frequency is set to 20-40 kHz, and the treatment time is 5-10 minutes.

[0025] As a preferred embodiment of this example, in step S2, before simultaneously adding appropriate amounts of vitamin E and rosemary extract to the nano-embedded emulsion, vitamin E and rosemary extract are respectively subjected to nano-embedded treatment to form nano-sized antioxidant particles, which are then simultaneously added to the nano-embedded emulsion.

[0026] In a preferred embodiment of this invention, an appropriate amount of photoinitiator is added during the curing process in step S133.

[0027] As a preferred embodiment of this example, after the S133 curing treatment, microcrystalline cellulose is further added as a stabilizer, with a mass percentage of 0.1% to 0.3%, and is uniformly dispersed in the nano-embedded emulsion by vortex mixing.

[0028] In summary, the technical effects and advantages of this invention are as follows:

[0029] The present invention has a reasonable structure. The complex of peony seed oil and β-lactoglobulin prepared by the present invention exhibits excellent antioxidant properties. By designing a composite antioxidant system in combination with sodium octenyl succinate starch and chitosan complex, a double protective barrier is formed inside and outside the nanocapsule, which effectively delays the oxidation process of the complex. Moreover, by using microemulsion-nano-encapsulation technology, the present invention achieves multi-level protection of active ingredients and significantly improves the storage stability of the complex. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0031] Figure 1 These are experimental data on the antioxidant properties of the complex;

[0032] Figure 2 Store stability experimental data for the complex;

[0033] Figure 3 SEM images showing the embedding effect of different protein ligands at different concentrations;

[0034] Figure 4Laser confocal images of different protein ligands;

[0035] Figure 5 Zeta data for different protein ligands;

[0036] Figure 6 Particle size distribution of β-lactoglobulin at a mass ratio of 3%;

[0037] Figure 7 Particle size distribution of ovalbumin at a mass ratio of 3%;

[0038] Figure 8 Particle size diagram of lactoferrin at a mass ratio of 5%. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Example: A complex of peony seed oil and β-lactoglobulin, comprising the following components by weight percentage:

[0041] Peony seed oil 5%~15%, β-lactoglobulin 3%, complex antioxidant system 0.1%~1%, lecithin 0.1%~0.5%, prebiotics 0.5%~2%, the remainder is purified water;

[0042] The compound antioxidant system contains 0.1% to 1% vitamin E (0.05% to 0.3%) and rosemary extract (0.05% to 0.7%).

[0043] As a preferred embodiment of this example, a method for preparing a complex of peony seed oil and β-lactoglobulin includes the following steps;

[0044] S1. Preparation of microemulsion-nano-encapsulated composite emulsion

[0045] S11. Peony seed oil and β-lactoglobulin solution are mixed in a certain ratio, and lecithin is added as a co-emulsifier. A crude emulsion is formed by using a high-speed shearing machine.

[0046] S12. Microemulsification treatment: The crude emulsion is microemulsified by a homogenizer to reduce the droplet size distribution D50 to the range of 0.2-0.5μm;

[0047] S13, Implementation of Nano-Encapsulation Technology

[0048] S131, Wall material preparation: Sodium octenyl succinate starch and chitosan are dissolved in an aqueous phase to form a positively charged nano-embedded wall material solution.

[0049] S132, Composite Coagulation: The microemulsion is slowly added dropwise to the wall material solution, and the pH is adjusted to 4.5 to induce electrostatic composite coagulation, forming nanocapsules with an average particle size of 80-120 nm.

[0050] S133, Curing treatment, adding glutaraldehyde for brief cross-linking, followed by dialysis to remove residual cross-linking agent;

[0051] Nano-encapsulation technology enables targeted delivery and sustained release of active ingredients, significantly improving bioavailability. At the same time, the antioxidant properties of the wall material can further protect peony seed oil from oxidation.

[0052] S2. Addition of compound antioxidants: Appropriate amounts of vitamin E and rosemary extract are added simultaneously to the nano-embedded emulsion. Uniform dispersion is achieved through vortex mixing, and the entire mixing process is carried out under nitrogen protection to control the dissolved oxygen content ≤0.2 mg / L.

[0053] Vitamin E and rosemary extract are nanoscale encapsulated to form antioxidant particles with an average particle size of 80-120 nm, which are directly embedded inside the nanocapsules to form an internal protective barrier. The complex antioxidant system and peony seed oil are coexisting in the core of the nanocapsules, reducing the direct contact between the oil and oxygen through physical isolation.

[0054] Vitamin E, as a fat-soluble antioxidant, preferentially neutralizes lipid peroxidation free radicals; phenolic substances (such as sarsaparilla acid) in rosemary extract inhibit oxidation chain reactions by chelating metal ions.

[0055] The nano-embedded wall material uses a complex of sodium octenyl succinate starch and chitosan to form an outer wall barrier. The hydroxyl and amino groups in its molecular structure can chelate oxidizing metal ions (such as...). , The oxidation reaction rate catalyzed by metal ions is reduced; the composite antioxidant system, together with sodium octenyl succinate starch and chitosan complex, forms a double protection inside and outside the nanocapsule, which extends the oxidation induction period to more than 3 times that of the traditional formula; inert gas protection: the entire mixing process is carried out under nitrogen protection, and the dissolved oxygen content is controlled below 0.2 mg / L. The nitrogen-filled environment effectively inhibits the oxidation reaction, and together with antioxidants, it forms a full-process anti-oxidation system.

[0056] S3, pH adjustment and sterilization

[0057] S31. Isoelectric point adjustment: The pH of the emulsion was precisely adjusted to 6.8±0.1 using a citrate / disodium hydrogen phosphate buffer solution, so that the zeta potential of β-lactoglobulin reached -5.2 mV;

[0058] pH adjustment optimizes the stability of the interfacial membrane while avoiding the damage of active ingredients to extreme pH levels.

[0059] S32. Mild sterilization: Pasteurization combined with pulsed light treatment is used to ensure that the total number of colonies is ≤10 CFU / g, while the α-linolenic acid retention rate is ≥92%.

[0060] S4. Nitrogen-filled packaging: The sterilized emulsion is filled into multi-layer co-extruded aluminum foil bags, and nitrogen is used to replace the oxygen residue until it is ≤0.3%, ensuring a heat seal strength of ≥30 N / 15mm; the combined sterilization process preserves nutritional activity to the maximum extent while ensuring food safety.

[0061] The preparation method includes the following: 1. Microemulsification process (microemulsification significantly increases the surface area of ​​the droplets, promotes the interfacial adsorption of β-lactoglobulin and peony seed oil, forming a stable "oil-in-water" structure; and firstly, high-pressure homogenization (20 MPa) breaks down large droplets, and then low-pressure homogenization (5 MPa) reconstructs the interfacial film, solving the problems of wide particle size distribution and fragile interfacial film caused by single high-pressure homogenization), and nano-encapsulation (the pH sensitivity of chitosan allows the nanocapsules to remain intact in the stomach (pH 1.5-3.5), and when they reach the intestine (pH 6.8-7.4), the wall material swells and releases peony seed oil, avoiding the destruction of active ingredients by gastric acid), achieving multi-level protection of active ingredients. In vitro simulated digestion experiments show that bioavailability is improved to 78%;

[0062] II. Enhanced antioxidant system: The combination of compound antioxidants and sodium octenyl succinate starch complex with chitosan forms a double protection inside and outside the nanocapsule, which extends the oxidation induction period to 3 times that of traditional formulations.

[0063] Third, the chitosan-starch composite wall material is pH sensitive and can control the release of peony seed oil in the weakly alkaline environment of the intestine, thereby improving the targeted delivery efficiency.

[0064] In a preferred embodiment of this invention, raw material pretreatment is performed between steps S1, including the following steps:

[0065] S10: Peony Seed Oil Refining: Selected peony seed oil with α-linolenic acid content ≥40% is subjected to low-temperature dewaxing, activated clay adsorption decolorization and molecular distillation treatment in sequence to ensure peroxide value ≤2.0 meq / kg;

[0066] S20: β-lactoglobulin purification: β-lactoglobulin was extracted by chromatographic separation technology, concentrated by ultrafiltration, freeze-dried and reconstituted to a concentration of 2%, and pre-emulsified by adjusting the pH to 7.0.

[0067] β-lactoglobulin has better intestinal compatibility, and pre-emulsification helps to facilitate the rapid formation of subsequent emulsion systems.

[0068] As a preferred embodiment of this example, in S21, a homogenizer is used for two-step homogenization: a first high-pressure homogenization controlled at 20 MPa, and a second low-pressure homogenization controlled at 5 MPa.

[0069] The first step, high-pressure homogenization (20 MPa), involves breaking up oil phase agglomerates with high shear force to form initial droplet clusters (D50≈0.8μm), while simultaneously generating a small number of submicron-sized droplets (D90<1.5μm). Energy input at this stage leads to the initial formation of the interfacial film, but uneven particle size distribution persists.

[0070] The second step, low-pressure homogenization (5 MPa), achieves "fine-tuning" of the emulsion droplets at a lower energy density. Cavitation further breaks down large droplets (>1.0 μm) while preventing excessive shearing that leads to the re-aggregation of small droplets (<0.3 μm). This results in a bimodal distribution (D50 = 0.45 μm, D90 = 0.85 μm), which ensures system fluidity (viscosity <50 mPa·s) while increasing packing density through the filling effect of small droplets, improving space utilization by 10.7% compared to single-step homogenization.

[0071] The first step, high-pressure homogenization, causes β-lactoglobulin molecules to be rapidly adsorbed onto the surface of newly formed oil droplets, forming an initial interfacial film (thickness ≈ 8 nm). The second step, low-pressure homogenization, provides a mild environment, allowing unadsorbed β-lactoglobulin molecules to be replenished to the interface through a diffusion-rearrangement mechanism, forming a bilayer structure (total thickness ≈ 15 nm).

[0072] Increased cross-linking density: The two-step treatment increased the interfacial protein coverage from 78% in a single homogenization to 92%. At the same time, lecithin molecules inserted into the hydrophobic region of β-lactoglobulin in the second homogenization step to form a "protein-phospholipid" complex interface, which improved the interfacial elastic modulus.

[0073] Oxygen permeation barrier: The bilayer interfacial membrane reduces the oxygen diffusion coefficient from 1.2×10-9 m² / s in a single homogeneous process to 6.5×10-10 m² / s, which is equivalent to increasing the equivalent oxidation barrier thickness by 2.3 times.

[0074] Improved antioxidant utilization: The particle size reduction increased the partition coefficient of vitamin E in the oil phase from 0.82 in a single homogenization to 1.15. At the same time, the loading rate of rosemary extract by the nano-encapsulated wall material (chitosan-starch complex) increased to 92%, forming a dual antioxidant network of "interfacial adsorption-wall material encapsulation".

[0075] The two-step homogenization process, through the synergistic effect of "particle size gradient control - interface film reconstruction - antioxidant network enhancement", not only solves the problems of wide particle size distribution, fragile interface film and insufficient oxidation protection that exist in single high-pressure homogenization, but also significantly improves product stability, functional release characteristics and process economy.

[0076] In a preferred embodiment of this invention, during step S11, while the high-speed shearing machine is forming the crude emulsion, an ultrasonic generator is simultaneously activated to perform ultrasonic treatment on the mixture. The ultrasonic frequency is set to 20-40 kHz, and the treatment time is 5-10 minutes.

[0077] The cavitation effect of ultrasound can generate strong microjets and shock waves, effectively breaking the aggregation between β-lactoglobulin molecules, promoting their uniform dispersion in the oil phase, significantly improving the stability of the emulsion, and providing a basis for a more uniform distribution of antioxidant components in the complex.

[0078] Ultrasonic-assisted emulsification can refine emulsion droplets and increase their surface area, thereby improving emulsification efficiency, forming a more stable emulsion system, and helping to effectively retain antioxidant components in the complex.

[0079] In the frequency range of 20-40 kHz, the cavitation effect is most significant, which can generate enough energy to break the aggregation between β-lactoglobulin molecules and promote their uniform dispersion in the oil phase.

[0080] When the frequency is below 20 kHz, the cavitation effect of ultrasound weakens, and the energy generated is insufficient to effectively break up the aggregation between β-lactoglobulin molecules, thus affecting the emulsification effect. This may lead to decreased emulsion stability and uneven distribution of antioxidant components;

[0081] When the frequency exceeds 40 kHz, the cavitation effect of ultrasound may become excessive, generating too many microjets and shock waves, which can damage the emulsion system. This may lead to droplet rupture, emulsion stratification, or precipitation, thereby affecting the stability and antioxidant properties of the complex.

[0082] As a preferred embodiment of this example, in step S2, before simultaneously adding appropriate amounts of vitamin E and rosemary extract to the nano-embedded emulsion, vitamin E and rosemary extract are respectively subjected to nano-embedded treatment to form nano-sized antioxidant particles, which are then simultaneously added to the nano-embedded emulsion.

[0083] The combination of nanoscale antioxidants and nano-encapsulation technology forms a dual antioxidant protection system, which significantly improves the antioxidant performance of the product and provides comprehensive antioxidant protection for the complex.

[0084] In a preferred embodiment of this invention, an appropriate amount of photoinitiator is added during the curing process in step S133.

[0085] By introducing photoinitiators (such as benzophenone), the photoinitiators are activated by ultraviolet irradiation during the curing process, which promotes the cross-linking and fixation of antioxidants (such as vitamin E and rosemary extract) in the nano-embedded wall material, forming a more stable antioxidant network, extending the shelf life of the product, and ensuring that the complex maintains excellent antioxidant properties during storage and use.

[0086] As a preferred embodiment of this example, after the S133 curing treatment, microcrystalline cellulose is further added as a stabilizer, with a mass percentage of 0.1% to 0.3%, and is uniformly dispersed in the nano-embedded emulsion by vortex mixing.

[0087] The addition of microcrystalline cellulose significantly improves the stability of the complex during storage and use. Microcrystalline cellulose has excellent thickening and stabilizing properties, effectively preventing the aggregation and precipitation of nanocapsules and maintaining the uniformity and stability of the emulsion. Simultaneously, microcrystalline cellulose also enhances the viscosity of the emulsion, reduces oxygen permeation, further protects peony seed oil from oxidation, and improves the overall quality and shelf life of the product.

[0088] Equal amounts of the complex prepared by the above process were divided into six groups. The oxidation induction time data were obtained for each group when the vitamin E content and rosemary extract content varied. Figure 1 As shown; equal amounts of the existing composite and the composite prepared by this process were taken and labeled as experimental group "I" and experimental group "II" respectively. The data on particle size change and oxidative stability change at room temperature are as follows: Figure 2 As shown, by Figure 1 and Figure 2 It is evident that this complex exhibits excellent antioxidant properties and storage stability.

[0089] Depend on Figure 3 As shown, this SEM image illustrates the embedding effect of different protein ligands at their optimal mass ratios. The red boxes represent the mass ratios with the best embedding effect for each ligand.

[0090] Depend on Figure 4 As shown, this set of images presents laser confocal images of different protein ligands, among which BLG is the preferred emulsifier, achieving a good balance between construction stability and biological activity;

[0091] Depend on Figure 5 As shown, zeta data indicates that BLG has the highest absolute value of the zeta site among the three ligand proteins, and its stability is better than the other two proteins.

[0092] Depend on Figure 6-8As shown, the particle size of the three proteins at their optimal mass ratios is as follows: BLG has the smallest particle size, resulting in a more uniform and stable emulsion; the average particle size of 3% OVA is 350 nm, the average particle size of 5% LTF is 1100 nm, and the average particle size of 3% BLG is 250 nm.

[0093] Therefore, the complex formed by this process with β-lactoglobulin at a mass ratio of 3% and peony seed oil has excellent stability.

[0094] Note: In the diagram, LTF stands for lactoferrin; BLG stands for β-lactoglobulin; and OVA stands for ovalbumin.

[0095] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A complex of Paeonia suffruticosa Andr. seed oil and beta-lactoglobulin, characterized by: Comprise the following mass percentage components, Peony seed oil 5%~15%, beta-lactoglobulin 3%, composite antioxidant system 0.1%~1%, lecithin 0.1%~0.5%, prebiotic 0.5%~2%, and the rest is purified water; The composite antioxidant system 0.1%~1% includes vitamin E 0.05%~0.3% and rosemary extract 0.05%~0.7%.

2. The method of claim 1, wherein the method of preparing a complex of Paeonia suffruticosa Andr. seed oil and beta-lactoglobulin is characterized by: Comprise the following steps: S1, microemulsion-nano embedding composite emulsion preparation S11, mix peony seed oil and beta-lactoglobulin solution according to the ratio, and add lecithin as a synergistic emulsifier, and form a coarse emulsion by using a high-speed shearing machine; S12, microemulsion treatment: the coarse emulsion is treated by a homogenizer for microemulsion, so that the droplet size distribution D50 is reduced to the interval of 0.2-0.5 μm; S13, nano embedding technology implementation S131, wall material preparation, dissolve sodium octenyl succinate starch and chitosan in the water phase to form a positively charged nano embedding wall material solution; S132, composite coagulation, slowly add the microemulsion emulsion to the wall material solution, adjust the pH to 4.5 to induce electrostatic composite coagulation, and form nano capsules with an average particle size of 80-120 nm; S133, curing treatment, add glutaraldehyde for short crosslinking, and then dialysis to remove residual crosslinking agent; S2, composite antioxidant addition, simultaneously add appropriate vitamin E and rosemary extract in the nano embedding emulsion, and uniformly disperse by vortex mixing, and the whole mixing process is carried out under nitrogen protection, and the dissolved oxygen content is controlled to be ≤0.2 mg / L; S3, pH regulation and sterilization S31, isoelectric point adjustment: use citric acid / disodium hydrogen phosphate buffer to accurately adjust the pH of the emulsion to 6.8±0.1, so that the beta-lactoglobulin ζ potential reaches-5.2 mV; S32, mild sterilization: adopt pasteurization combined with pulse strong light treatment to ensure that the total number of colonies is ≤10 CFU / g, while the retention rate of alpha-linolenic acid is ≥92%; S4, nitrogen filling packaging: the sterilized emulsion is filled into a multi-layer co-extruded aluminum foil bag, and the residual oxygen is replaced to ≤0.3% by nitrogen filling, and the heat sealing strength is ensured to be ≥30 N / 15 mm.

3. The method for preparing a complex of peony seed oil and β-lactoglobulin according to claim 2, characterized in that: Raw material pretreatment is carried out between S1, comprising the following steps: S10: peony seed oil refining: select peony seed oil with alpha-linolenic acid content ≥40%, and sequentially perform low-temperature dewaxing, activated white clay adsorption decolorization and molecular distillation treatment to ensure that the peroxide value is ≤2.0 meq / kg; S20: beta-lactoglobulin purification: beta-lactoglobulin is extracted by chromatographic separation technology, concentrated by ultrafiltration, freeze-dried and then re-dissolved to 2% concentration, and the pH is adjusted to 7.0 for pre-emulsification.

4. The method of claim 2, wherein the method of preparing a complex of Paeonia suffruticosa Andr. seed oil and beta-lactoglobulin is characterized by: In the step S21, two-step homogenization is carried out by using a homogenizer, the first high-pressure homogenization is controlled at 20 MPa, and the second low-pressure homogenization is controlled at 5 MPa.

5. The method of claim 1, wherein the method of preparing a complex of Paeonia suffruticosa Andr. seed oil and beta-lactoglobulin is characterized by: In the step S11, during the process of forming a coarse emulsion by a high-speed shearing machine, an ultrasonic generator is started at the same time to treat the mixed liquid, the ultrasonic frequency is set to 20-40 kHz, and the treatment time is 5-10 minutes.

6. The method of claim 1, wherein the method of preparing a complex of Paeonia suffruticosa Andr. seed oil and beta-lactoglobulin is characterized by: In the step S2, before adding the appropriate amount of vitamin E and rosemary extract into the nano-embedding emulsion, the vitamin E and rosemary extract are respectively subjected to nano-scale embedding treatment to form nano-scale antioxidant particles, and then are synchronously added into the nano-embedding emulsion.

7. The method for preparing a complex of peony seed oil and β-lactoglobulin according to claim 7, characterized in that: In the curing treatment of the step S133, an appropriate amount of photoinitiator is added.

8. The method of claim 1, wherein the method of preparing a complex of Paeonia suffruticosa Andr. seed oil and beta-lactoglobulin is characterized by: After the S133 curing treatment, microcrystalline cellulose is further added as a stabilizer, and the mass percentage is 0.1%~0.3%, which is uniformly dispersed in the nano-embedding emulsion by vortex mixing.

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