One-step method for preparing tuna oil Pickering emulsion

Abstract

The present invention discloses a method for one-step preparation of tuna oil Pickering emulsion, which includes: adding an aqueous solution of alkaline zein and an aqueous solution of acidic pectin, which are rapidly mixed in equal volume, as the aqueous phase into channel one, adding tuna oil as the oil phase into channel two, and adjusting the pressure and flow rate ratio through a dual-channel microfluidic device for homogenization to obtain a high-concentration tuna oil Pickering emulsion; wherein, the aqueous phase alkaline zein aqueous solution and acidic pectin aqueous solution will self-assemble to form composite nanoparticles through pH-driven, and are mixed and homogenized with tuna oil in one step through dual-channel adjustment. Compared with the traditional method for Pickering emulsion, the operation is convenient and the process is simple; the obtained tuna oil Pickering emulsion droplets are uniform and have a small particle size, and have good structural stability, anti-lipid oxidation characteristics and intestinal targeting and sustained release effects.

Description

Technical Field

[0001] The present invention relates to the technical field of food Pickering emulsion preparation, and particularly to a method for preparing zein / pectin composite nanoparticles driven by pH and mixing with tuna oil in one step based on a two-channel microfluidic technology to prepare tuna oil Pickering emulsion. The Pickering emulsion has good structural stability, anti-lipid oxidation and intestinal sustained-release applications. Background Art

[0002] Tuna oil refers to a mixed lipid extracted from tuna and is the main provider of ω-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Because of its rich ω-3 polyunsaturated fatty acids, tuna oil has various regulatory and metabolic effects in the human body, improves human health, and can prevent cardiovascular diseases, premenstrual syndrome, inhibit inflammation, improve memory and inhibit tumors, etc. However, due to problems such as strong fishy smell, high fat solubility, easy oxidation, and intolerance to acids and alkalis, the application of tuna oil in the food industry is limited. Constructing tuna oil Pickering emulsion is a potential way to solve the above problems.

[0003] Pickering emulsion refers to a system that can be stabilized by solid particles at the micron or even nanometer scale. It is a system that can achieve stability both thermodynamically and kinetically. It can prevent the coalescence of emulsion droplets through particle interface action, reduce the total free energy of the system, and produce a spatial physical barrier effect. Depending on the surface hydrophobicity of the particles, it is considered irreversible adsorption. Compared with traditional emulsions, Pickering emulsions have great advantages: the addition amount of the stabilizer is small, saving raw material costs; environmentally friendly, and factors such as temperature and ionic strength have little influence on the emulsion. The preparation of Pickering emulsion often requires two steps, namely: preparation of the stabilizer (solid particles) and oil-water rotor-stator shearing. Among them, common methods for preparing solid particles include anti-solvent precipitation method, isoelectric point method, solvent evaporation method, thermal-induced aggregation method, enzymatic method, etc., but they all have disadvantages. For example, the anti-solvent precipitation method will introduce organic chemicals during the preparation process, which may cause risks such as flammability and explosion; the nanoparticles prepared by the isoelectric point method are easily affected by pH and lack stability; the solvent evaporation method and thermal-induced aggregation method have the disadvantages of long time consumption and high energy consumption; while the enzymatic method has strong specificity and high cost. In addition, rotor-stator shearing easily damages the particles and aggregates near the interface of the Pickering emulsion, resulting in uneven droplets and larger particle sizes.

[0004] Based on this, this project proposes a method for one-step preparation of Pickering emulsions using pH-driven dual-channel microfluidics technology. The pH-driven method for preparing solid particles has significant advantages such as avoiding the flammability risk and explosion hazard caused by the use of organic chemicals in the preparation process, simple operation, short preparation time, green energy-saving, low cost, and suitability for industrial scale. Compared with traditional Pickering emulsion preparation methods, the dual-channel microfluidics technology realizes the processes of solid particle preparation and oil-water phase mixing and shearing in one step with fewer operation procedures and shorter operation time. That is, the main mechanism of forming emulsions by this technology is to endow the added aqueous phase and oil phase with high-pressure and high-speed flow characteristics through a high-pressure intensifier, so that the mixed phases collide with each other to achieve smaller droplet sizes. At the same time, the stabilizer nanoparticles in the aqueous phase can also quickly adsorb and cover the droplets to form a uniform, stable emulsion with smaller droplet sizes. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention provides a method for one-step preparation of tuna oil Pickering emulsions.

[0006] The technical solution of the present invention is as follows:

[0007] A method for one-step preparation of tuna oil Pickering emulsions, the method being: based on pH-driven dual-channel microfluidics technology, mixing and homogenizing the aqueous phase of nanoparticles and the oil phase in one step to obtain tuna oil Pickering emulsions;

[0008] Among them, the aqueous phase is a zein / pectin composite nanoparticle solution, which is prepared by the pH-driven method from a zein aqueous solution with pH = 11 - 12 and a pectin aqueous solution with pH = 2 - 3;

[0009] The oil phase is tuna oil.

[0010] Furthermore, the method for one-step preparation of tuna oil Pickering emulsions according to the present invention includes the following steps:

[0011] (1) Prepare a zein solution: Add zein to a strong base solution, seal and stir to dissolve, and adjust the pH to 11 - 12 to obtain a zein solution;

[0012] Preferably, in the zein solution, the mass concentration of zein is 10 mg / mL;

[0013] (2) Prepare a pectin solution: Add pectin to water, stir, let stand for sufficient hydration, and adjust the pH to 2 - 3 to obtain a pectin solution;

[0014] Preferably, the mass concentration ratio of the zein solution to the pectin solution is 20:1 - 1:2;

[0015] (3) Prepare the composite nanoparticle solution: Mix the zein solution obtained in step (1) and the pectin solution obtained in step (2) in equal volumes, and adjust the pH to 7 to obtain a composite nanoparticle solution (aqueous phase);

[0016] Preferably, after mixing the zein solution and the pectin solution, finely adjust the pH to 7;

[0017] (4) Dual-channel mixing and homogenizing emulsification: Introduce the composite nanoparticle solution obtained in step (3) and tuna oil into channels 1 and 2 of a dual-channel microfluidic device respectively, and through one-step mixing and homogenization, obtain a tuna oil Pickering emulsion;

[0018] Preferably, the flow rate ratio of the composite nanoparticle solution in channel 1 to tuna oil in channel 2 is 9:1 to 1:9;

[0019] Preferably, the homogenization pressure of the dual-channel microfluidic device is 9 to 19 kpsi.

[0020] The innovation of the present invention lies in:

[0021] 1. One-step preparation: For the preparation of traditional Pickering emulsions, it is necessary to first prepare zein nanocomposite particles by the anti-solvent method and then shear-mix them with the oil phase, with cumbersome operations. In the present invention, an aqueous solution of alkaline zein and an aqueous solution of acidic pectin that are rapidly mixed in equal volumes are used as the aqueous phase, and tuna oil is used as the oil phase. By adjusting the flow rate of the dual-channel microfluidic and high-pressure homogenization, a high-concentration tuna oil Pickering emulsion can be obtained in one step. In the present invention, the aqueous alkaline zein solution and the aqueous acidic pectin solution form composite nanoparticles through rapid pH-driven self-assembly. By adjusting the dual-channel flow rate ratio, homogenization pressure and mixing and homogenizing with tuna oil in one step, the preparation of Pickering emulsions can be achieved. The present invention is convenient to operate, with a simple process, and the obtained tuna oil Pickering emulsion has good structural stability, anti-lipid oxidation characteristics and intestinal sustained-release effects.

[0022] 2. Green and environmentally friendly: During the preparation process of the Pickering emulsion of the present invention, water is used as the solvent, avoiding the use of organic solvents and ensuring environmental and operator safety and environmental protection.

[0023] The beneficial effects of the present invention are as follows:

[0024] In the preparation method of the present invention, zein and pectin required are widely sourced and inexpensive, and have good biocompatibility. The preparation method used in the present invention has a simple and green process. Compared with the traditional method of preparing composite particles by the alcohol-soluble anti-solvent method and then shear-mixing with the oil phase, this method does not involve any organic reagents and can obtain Pickering emulsions with smaller particle sizes and more stable structures in one step, which is easy to be popularized and applied in large-scale enterprise production. In addition, the tuna oil Pickering emulsion prepared in this project has good anti-lipid oxidation characteristics and intestinal sustained-release effects due to its uniform droplets and smaller particle sizes, and has great application potential in the fields of food, medicine, materials, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a process flow comparison diagram between the present invention and the traditional method.

[0026] Figure 2 It is a schematic diagram of the equipment of the present invention.

[0027] Figure 3 It is a comparison diagram (A) of the average particle size and polydispersity index (PDI) of nanoparticles with different mass ratios in Example 1, Comparative Example 1, and Comparative Example 2, and a comparison diagram (B) of ζ potential values.

[0028] Figure 4 It is a comparison diagram (A) of the average particle size of emulsions in Examples 1 to 4 and Comparative Example 1, and a comparison diagram (B) of optical microscopes.

[0029] Figure 5 It is a diagram showing the change of lipid hydroperoxide value in the emulsions of Comparative Example 1 and Example 1 within 14 days.

[0030] Figure 6 It is a diagram showing the change of TBARS value in the emulsions of Comparative Example 1 and Example 1 within 14 days.

[0031] Figure 7 It is a diagram showing the change of FFA release rate of the tuna oil Pickering emulsions of Comparative Example 1 and Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0032] The present invention will be further described below in conjunction with specific embodiments. The following are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto.

[0033] Comparative Example 1

[0034] (1) Add 1 g of zein to 100 mL of 80% ethanol aqueous solution, seal and stir at room temperature for 30 min to obtain a zein solution.

[0035] (2) Add a certain mass of pectin to 150 mL of water. The mass concentration ratio of zein solution to pectin solution is 20:1, 10:1, 5:1, 2:1, 1:1, 1:2. Stir well for 30 min and hydrate overnight to obtain the pectin solution.

[0036] (3) Mix the zein solution in step (1) and the pectin solution in step (2) at a volume ratio of 1:3. Under sealed conditions, stir at 700 rpm for 30 min by the anti-solvent precipitation method to obtain the composite nanoparticle solution.

[0037] (4) Mix tuna oil and the best composite nanoparticle solution obtained in step (3) at an oil-water ratio of 7:3 (v / v). In an ice bath, use a high-speed shearer to shear at 18000 r / min for 3 min to obtain the emulsion.

[0038] In this comparative example, a gradient test was conducted on the mass concentration ratio of zein and pectin solution in the composite nanoparticles in step (3), and the average particle size, ζ potential, and polydispersity index (PDI) of the composite nanoparticles were measured. As Figure 3 shown, when the mass concentration ratio of zein to pectin solution is 10:1, the composite nanoparticles have a smaller average particle size and PDI value, and the absolute value of the ζ potential value is larger. Therefore, 10:1 is the best mass ratio for preparing the obtained composite nanoparticles.

[0039] Comparative Example 2

[0040] (1) Add 1 g of milk protein (taking casein as an example) to 100 mL of a strong base (NaOH) solution with pH = 12. Seal and stir at room temperature for 30 min to obtain the casein solution.

[0041] (2) Add a certain mass of pectin to 150 mL of water. The mass concentration ratio of zein solution to pectin solution is 20:1, 10:1, 5:1, 2:1, 1:1, 1:2. Stir well for 30 min and hydrate overnight to obtain the pectin solution.

[0042] (3) Adjust the pH of the casein solution obtained in step (1) to pH = 12. [[ID=ed24]]

[0043] (4) Adjust the pH of the pectin solution obtained in step (2) to pH = 2.

[0044] (5) Mix the casein solution in step (3) and the pectin solution in step (4) in equal volumes, slightly adjust the solution to pH = 7, and obtain the composite particle solution by the pH-driven method.

[0045] Example 1

[0046] (1) Add 1 g of zein to 100 mL of a strong base (NaOH) solution with a pH of 12, seal and stir at room temperature for 30 min to obtain a zein solution.

[0047] (2) Add a certain mass of pectin to 150 mL of water. The mass concentration ratio of the zein solution to the pectin solution is 20:1, 10:1, 5:1, 2:1, 1:1, 1:2. Stir well for 30 min and hydrate overnight to obtain a pectin solution.

[0048] (3) Adjust the pH of the zein solution obtained in step (1) to 12.

[0049] (4) Adjust the pH of the pectin solution obtained in step (2) to 2.

[0050] (5) Mix the zein solution in step (3) and the pectin solution in step (4) in equal volumes, slightly adjust the solution to pH = 7, and obtain a composite nanoparticle solution by the pH-driven method.

[0051] (6) Add the best composite nanoparticle solution obtained in step (5) to channel one, add tuna oil to channel two, and set the channel flow rate ratio of the oil phase to the water phase in the dual-channel microfluidic device to 7:3. Under the condition of a homogenization pressure of 17 kpsi, homogenize once to obtain a Pickering emulsion.

[0052] In this example, a gradient test was conducted on the mass concentration ratio of zein to pectin solution in the composite nanoparticles in step (3), and the average particle size, ζ potential, and polydispersity index (PDI) of the composite nanoparticles were measured. As Figure 3 shown, when the mass concentration ratio of zein to pectin solution is 10:1, the composite nanoparticles have a smaller average particle size and PDI value, and the absolute value of the ζ potential value is larger. Therefore, 10:1 is the best mass ratio for preparing the obtained composite nanoparticles. At the same time, the particle size and PDI value of the composite nanoparticles prepared by the pH-driven method in Example 1 are smaller than those of the composite nanoparticles prepared by the anti-solvent precipitation method in Comparative Example 1, and the absolute value of the ζ potential value is larger. That is, compared with the traditional anti-solvent precipitation method, it can be concluded that the composite nanoparticles obtained by the pH-driven method have a stable structure.

[0053] In addition, Comparative Example 2 used milk protein (casein as an example) to prepare composite particles. The particle size measured in its solution has reached the micron level, and the PDI value is 1, that is, stable composite particles cannot be formed. The performance of self-assembling and binding with polysaccharides by the pH-driven method is not as good as that of zein.

[0054] Example 2

[0055] (1) Add 1 g of zein to 100 mL of a strong base (NaOH) solution with a pH of 12, seal and stir at room temperature for 30 min to obtain a zein solution.

[0056] (2) Add a certain mass of pectin to 150 mL of water. The mass concentration ratio of the zein solution to the pectin solution is 10:1. Stir well for 30 min and hydrate overnight to obtain a pectin solution.

[0057] (3) Adjust the pH of the zein solution obtained in step (1) to 12.

[0058] (4) Adjust the pH of the pectin solution obtained in step (2) to 2.

[0059] (5) Mix the zein solution in step (3) and the pectin solution in step (4) in equal volumes, slightly adjust the solution to pH = 7, and obtain a composite nanoparticle solution by the pH-driven method.

[0060] (6) Add the best composite nanoparticle solution obtained in step (5) to channel one, add tuna oil to channel two, and set the channel flow rate ratio of the oil phase to the water phase in the dual-channel microfluidic device to 1:1. Homogenize once at a homogenization pressure of 17 kpsi to obtain a Pickering emulsion.

[0061] Example 3

[0062] (1) Add 1 g of zein to 100 mL of a strong base (NaOH) solution with a pH of 12, seal and stir at room temperature for 30 min to obtain a zein solution.

[0063] (2) Add a certain mass of pectin to 150 mL of water. The mass concentration ratio of the zein solution to the pectin solution is 10:1. Stir well for 30 min and hydrate overnight to obtain a pectin solution.

[0064] (3) Adjust the pH of the zein solution obtained in step (1) to 12.

[0065] (4) Adjust the pH of the pectin solution obtained in step (2) to 2.

[0066] (5) Mix the zein solution in step (3) and the pectin solution in step (4) in equal volumes, slightly adjust the solution to pH = 7, and obtain a composite nanoparticle solution by the pH-driven method.

[0067] (6) Add the best composite nanoparticle solution obtained in step (5) to channel one, add tuna oil to channel two, and set the channel flow rate ratio of the oil phase to the water phase in the dual-channel microfluidic device to 3:7. Under the condition of a homogenization pressure of 17 kpsi, homogenize once to obtain Pickering emulsion.

[0068] Example 4

[0069] (1) Add 1 g of zein to 100 mL of a strong base (NaOH) solution with pH = 12, seal and stir at room temperature for 30 min to obtain a zein solution.

[0070] (2) Add a certain mass of pectin to 150 mL of water. The mass concentration ratio of the zein solution to the pectin solution is 10:1. Stir well for 30 min and hydrate overnight to obtain a pectin solution.

[0071] (3) Adjust the pH of the zein solution obtained in step (1) to pH = 12.

[0072] (4) Adjust the pH of the pectin solution obtained in step (2) to pH = 2.

[0073] (5) Mix the zein solution in step (3) and the pectin solution in step (4) in equal volumes, slightly adjust the solution to pH = 7, and obtain a composite nanoparticle solution by the pH-driven method.

[0074] (6) Add the best composite nanoparticle solution obtained in step (5) to channel one, add tuna oil to channel two, and set the channel flow rate ratio of the oil phase to the water phase in the dual-channel microfluidic device to 1:9. Under the condition of a homogenization pressure of 17 kpsi, homogenize once to obtain Pickering emulsion.

[0075] The test methods and results of Pickering emulsions in the comparative examples and examples are as follows:

[0076] (1) Average particle size measurement and optical microscope observation

[0077] Dilute the prepared Pickering emulsion 1000 times and measure the particle size of the Pickering emulsion with a laser particle size analyzer.

[0078] Dilute the prepared Pickering emulsion 20 times and observe the microscopic morphology of the Pickering emulsion with an optical microscope, that is, the aggregation degree of emulsion droplets, the oil droplet diameter, and the network structure between oil droplets. And collect its images for comparison.

[0079] Results: Figure 4The results of the median particle size in (A) are as follows: Example 1 < Example 2 < Example 3 < Example 4 < Comparative Example 1. It can be seen that as the volume fraction of the oil phase decreases, the particle size of the Pickering emulsion gradually increases. In addition, at the same volume fraction of the oil phase, the particle size of the Pickering emulsion stabilized by the composite nanoparticles prepared by the anti-solvent precipitation method is larger than that of the Pickering emulsion stabilized by the composite nanoparticles prepared by the pH-driven method in the present invention. And Figure 4 The observation results of the optical microscope in (B) also coincide with the above results.

[0080] (2) Determination of lipid hydroperoxide (POV)

[0081] Place it in an electrothermal constant temperature incubator at 45 °C to promote the oxidation reaction, and take out the aliquots for the determination of the oxidation experiment at 0, 2, 4, 6, 8, 10, 12, and 14 d. Mix 0.2 mL of the emulsion sample with 1.5 mL of isooctane / 2-propanol (3:1, v / v) and vortex (10 s, three times). After centrifuging at 3400 g for 2 minutes, mix 200 μL of the organic solvent phase with 2.8 mL of methanol / 1-butanol (2:1, v / v). Add 15 μL of 3.94 M ammonium thiocyanate and 15 μL of ferrous solution (prepared by mixing 0.132 M BaCl2 and 0.144 M FeSO4) for hydrogen peroxide detection. After 20 minutes, measure the absorbance at 510 nm using a UV-visible spectrophotometer (Genesys 10, Thermo Scientific, USA). And use the standard curve made from hydrogen peroxide to determine the peroxide concentration. At the same time, use the same mass of tuna oil as the control group.

[0082] Results: Figure 5 It can be seen from that the POV of all groups gradually increases with time, and the oxidation of the control group is the fastest, and the oxidation rate of Comparative Example 1 is faster than that of Example 1, indicating that the prepared tuna oil Pickering emulsion of the present invention has better oxidation stability than the Pickering emulsion prepared by the traditional method.

[0083] (3) Determination of secondary oxidation product - malondialdehyde (TBARS)

[0084] Mix 1 mL of deionized water and 2 mL of TBA reagent in a 15 mL test tube and vortex for 30 s. Heat the test tube in boiling water for 25 min and then cool it at room temperature for 20 min. Subsequently, centrifuge at 2500 r / min for 20 min. After standing at room temperature for 15 min, filter the supernatant through a 0.22 μm hydrophilic microfiltration membrane, and measure the absorbance of the filtrate at 532 nm. Calculate the concentration of TBARS in the Pickering emulsion according to the standard curve of 1,1,3,3-tetraethoxypropane. At the same time, use the tuna oil dilution of the same mass as the control group.

[0085] Results: The TBARS value is one of the indicators characterizing the degree of secondary oxidation of lipids. It can be seen from Figure 6 that the TBARS value of the control group > the TBARS value of the comparative example > the TBARS value of the example. It can be seen that the Pickering emulsion prepared by the present invention has an effect on delaying oil oxidation, and the tuna oil Pickering emulsion prepared by the present invention has better anti-oil oxidation ability than the Pickering emulsion prepared by the traditional method.

[0086] (5) In vitro digestion simulation experiment

[0087] Oral digestion: Prepare 90 mL of simulated saliva (SSF) by taking 80.64 mg of KCl, 79.92 mg of NaH2PO4, 18 mg of KSCN, 26.82 mg of NaCl, 51.3 mg of Na2SO4, 98.46 mg of NaHCO3, 18 mg of urea, 1.35 mg of uric acid, and 54 mg of α-amylase. Take 15 mL of the Pickering emulsion in a dialysis bag and 90 mL of SSF and preheat them at 37 °C for 5 min. Place the dialysis bag into 90 mL of SSF. Quickly adjust the pH of the system to 6.8 with 1 mol / L HCl and digest it in a constant temperature shaking water bath (100 r / min) at 37 °C for 10 min. At each time point of 0, 2, 4, 6, 8, and 10 minutes, take out 5 mL of the release medium from the incubation bath.

[0088] Gastric digestion: Prepare simulated gastric fluid (SGF) by taking 180 mg of NaCl, 630 mg of HCl, and 288 mg of pepsin. Take 90 mL of SGF and preheat it in a 37 °C constant temperature water bath for 5 min. Place the dialysis bag after the above oral digestion into SGF, and quickly adjust the pH of the mixed system to 2.5 with 1 mol / L NaOH. Digest it in a constant temperature shaking water bath (100 r / min) at 37 °C for 2 h. At each time point of 10, 30, 60, 90, and 120 minutes, take out 5 mL of the release medium from the incubation bath.

[0089] Intestinal digestion: Take 550.5 mg of CaCl2·2H2O, 75 mg of bile salts, and 67.5 mg of pancreatin to prepare simulated intestinal fluid (SIF). After gastric digestion, quickly adjust the pH of the resulting system to 7.0 with 0.25 mol / L NaOH. Meanwhile, preheat the SIF in a 37°C constant temperature water bath for 5 min. Place the dialysis bag after gastric digestion into the SIF, and adjust the pH of the mixed system to 7.0 with 1 mol / L NaOH. Digest in a 37°C constant temperature shaking water bath (100 r / min) for 2 h. Continuously adjust with NaOH during this period to maintain the pH of the mixed system at 7.0. At each time point of 10, 30, 60, 90, and 120 minutes, take out 5 mL of the release medium from the incubation bath. Evaluate the cumulative release rate of fatty acids according to the amount of NaOH used for titration at different digestion stages.

[0090] Results: As Figure 7 shown, during the in vitro simulated digestion process, it can be found that since fatty acids are mainly absorbed in the small intestine, especially ω-polyunsaturated fatty acids can enter the blood to play physiological functions, it is of great significance to use zein-pectin composite nanoparticles to stabilize tuna oil Pickering emulsion for improving the targeted sustained release of ω-polyunsaturated fatty acids in vivo. During the simulated gastrointestinal digestion process, pepsin and pancreatin may hydrolyze zein, thus destroying the structure of the nanoparticles and causing the fatty acids in the stable Pickering emulsion to be released in SGF and SIF. The composite nanoparticles, however, have good pH stability and can stabilize the fatty acids in the Pickering emulsion to remain stable in SGF and be targeted released in SIF. Further, it can be seen that the release rate of the tuna oil Pickering emulsion in Example 1 in gastric juice is less than that in Comparative Example 1, and it can be concluded that the tuna oil Pickering emulsion prepared by the present invention has better intestinal targeting release characteristics than the Pickering emulsion prepared by the traditional method.

Claims

1. A method for one-step preparation of tuna oil Pickering emulsion, characterized in that, It includes the following steps: (1) Prepare a zein solution: Add zein to a strong alkali solution, seal and stir to dissolve, adjust the pH to 11 - 12 to obtain a zein solution; (2) Prepare a pectin solution: Add pectin to water, stir, let it stand for sufficient hydration, adjust the pH to 2 - 3 to obtain a pectin solution; (3) Prepare a composite nanoparticle solution: Mix the zein solution obtained in step (1) and the pectin solution obtained in step (2) in equal volumes, adjust the pH to 7 to obtain a composite nanoparticle solution; The mass concentration ratio of the zein solution to the pectin solution is 10:1; (4) Dual - channel mixing and homogenizing emulsification: Introduce the composite nanoparticle solution obtained in step (3) and tuna oil into channel 1 and channel 2 of a dual - channel microfluidic device respectively, and through one - step mixing and homogenization, obtain a tuna oil Pickering emulsion; The flow rate ratio of the composite nanoparticle solution in channel 1 to the tuna oil in channel 2 is 3:

7.

2. The one-step method for preparing tuna oil Pickering emulsion according to claim 1, characterized in that, In the zein solution, the mass concentration of zein is 10 mg / mL.

3. The one-step method for preparing tuna oil Pickering emulsion according to claim 1, characterized in that, The homogenization pressure of the dual - channel microfluidic device is 9 - 19 kpsi.

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