Zein-osa starch-tween-20 ternary complex pickering particles, and preparation method and application thereof

Abstract

The application belongs to the technical field of nanoparticle application, and particularly relates to a corn alcohol-soluble protein-OSA starch-tween-20 ternary composite Pickering particle and a preparation method and application thereof. The corn alcohol-soluble protein-OSA starch-tween-20 ternary composite Pickering particle and emulsion thereof are constructed under the condition of different concentrations of tween-20, the problems of instability of a corn alcohol-soluble protein-OSA starch composite system and easy stratification and flocculation in a storage process are solved, and the stability of the corn alcohol-soluble protein-OSA starch-tween-20 ternary composite Pickering particle and emulsion thereof is improved by adjusting the proportion of the content of tween-20 in the ternary composite system.

Description

Technical Field

[0001] This invention belongs to the field of nanoparticle application technology, specifically relating to a ternary composite Pickering particle of zein-OSA starch-Tween-20, its preparation method and application. Background Technology

[0002] An emulsion is a dispersion system composed of two immiscible liquids, where one phase exists as tiny droplets within the other. Due to the high free energy at the interface between the two phases, emulsions are thermodynamically unstable and tend to undergo phase separation to reduce the system's energy. Therefore, emulsifiers, such as surfactants or solid particles, are typically used to form and stabilize emulsions. Emulsifiers effectively reduce interfacial tension, thereby delaying droplet coalescence and extending the emulsion's shelf life. Among various synthetic emulsifiers, nonionic emulsifiers (such as Tween series polyoxyethylene sorbitan esters) are widely used in the preparation of nanoemulsions due to their excellent emulsifying properties and low cost. However, the adsorption of these traditional emulsifiers at the oil-water interface is mostly a dynamic and reversible process. When used alone, they are easily affected by external conditions such as pH and temperature, resulting in a limited interfacial film strength that is prone to desorption, leading to oil droplet aggregation and phase separation during storage. In contrast, Pickering emulsions exhibit superior stability and resistance to deformation. Their stabilization mechanism relies on the irreversible adsorption of solid colloidal particles at the interface between the two phases; these particles typically possess partial wettability. In particular, composite particles constructed from natural proteins and polysaccharides through self-assembly not only possess excellent biocompatibility and edibility but also allow for precise control of the emulsion structure by adjusting particle size, surface charge, and hydrophobicity. Furthermore, larger Pickering particles can establish stronger physical spatial barriers between droplets, effectively preventing droplet aggregation and coalescence. Therefore, Pickering emulsions are considered an important pathway to achieving highly stable, naturally safe food emulsion systems.

[0003] Zein is currently recognized as one of the most widely applicable and multifunctional biopolymers. Zein particles, either directly or in combination with hydrophilic colloids, can act as solid stabilizers at the oil-water interface, contributing to the construction and stabilization of Pickering emulsions. Given its strong hydrophobicity, antisolvent precipitation is often used to prepare its nanoparticles to improve the stability and bioavailability of its bioactive components. As a naturally sourced protein, zein nanoparticles have been considered a potential food-grade Pickering stabilizer and are gradually gaining application in the food industry. However, zein itself lacks charged groups and hydrophilic domains, exhibiting extremely strong hydrophobic properties. This leads to its tendency to aggregate hydrophobically in aqueous phases, resulting in poor solubility and dispersion stability. Furthermore, it readily aggregates and precipitates near its isoelectric point or under high ionic strength conditions, limiting its effectiveness in practical systems. Therefore, it is necessary to address the emulsion instability caused by using zein alone and overcome its application limitations.

[0004] To improve the stability of zein, existing technologies disclose the preparation of composite nanoparticles by combining it with polysaccharide raw materials. For example, CN114098076B discloses a method for preparing quercetin-zein / pectin / chitosan nanoparticles crosslinked with genipin. However, most chemical crosslinking agents are toxic, and the safety of protein nanoparticles with residual crosslinking agents is greatly reduced. CN106188437B discloses nanoparticles composed of zein and propylene glycol alginate, which are used to stabilize emulsions; however, emulsions containing these protein-polysaccharide nanoparticles are still difficult to maintain stability under different pH conditions.

[0005] Octenyl succinate starch ester (OSA starch) has attracted much attention due to its safety and biodegradability. It is a highly efficient amphiphilic compound formed by chemically modifying natural starch chains, simultaneously incorporating hydrophilic carboxylic acid groups and hydrophobic long-chain alkyl groups. This unique molecular structure gives it outstanding interfacial activity, especially in dealing with pH fluctuations or salt ion interference, where its emulsifying stability is often superior to many protein emulsifiers that rely on charge stabilization mechanisms. For example, CN117843998A attempted to combine OSA starch with strongly hydrophobic zein to construct a more stable composite emulsion system. However, these two components differ significantly in physical properties: zein is almost completely hydrophobic and lacks surface charge, while OSA starch possesses both hydrophilic and hydrophobic segments. This mismatch in polarity, charge, and hydrophilic / hydrophobic balance makes it difficult for them to spontaneously form a homogeneous and stable system during compounding, easily leading to problems such as uneven interfacial blending, particle aggregation, and even macroscopic phase separation.

[0006] Therefore, it is still necessary to find a way to solve the interfacial stability of the zein and OSA starch complex system. Summary of the Invention

[0007] To address the deficiencies and shortcomings of existing technologies, this invention provides a ternary composite self-assembly method based on zein, OSA starch, and Tween-20 to prepare highly stable and naturally safe Pickering particles and their emulsions.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0009] In a first aspect, the present invention provides a method for preparing pickering granules of a ternary composite of alcohol-OSA starch-Tween-20, the method comprising the following steps:

[0010] S1. Mix prolysin with ethanol / water solution, stir, adjust the pH of the system to 8.0 to obtain prolysin ethanol / water solution, then add the solution dropwise to water under continuous stirring to form prolysin nanoparticles, remove ethanol from the system, and concentrate the system to obtain prolysin aqueous solution;

[0011] S2. Mix OSA starch with water, stir, and adjust the pH of the system to 8.0 to obtain an OSA starch aqueous solution;

[0012] S3. The OSA starch aqueous solution prepared in S2 is added dropwise to the alcohol-soluble protein aqueous solution prepared in S1, and the mixture is stirred to fully mix the OSA starch and alcohol-soluble protein to obtain an alcohol-soluble protein-OSA starch binary nano-dispersion.

[0013] S4. Add Tween-20 to the dispersion prepared in S3, stir, and obtain alcohol-soluble protein-OSA starch-Tween-20 ternary composite Pickering particles.

[0014] Alternatively, in the above preparation method, the prolysin is zein, and the OSA starch is derived from corn starch.

[0015] Alternatively, in the above preparation method, the pH adjuster is a 1 mol / L NaOH standard solution.

[0016] Alternatively, in the above preparation method, in S1, the ethanol / water solution is 70%~85% ethanol / water solution by volume percentage, and the mass-volume concentration of the alcohol-soluble protein aqueous solution is 1.5%~2.5%.

[0017] Preferably, the ethanol / water solution is 75% ethanol / water solution by volume percentage.

[0018] Preferably, the mass-volume concentration of the alcohol-soluble protein aqueous solution is 1.8% to 2.2%.

[0019] More preferably, the mass-volume concentration of the alcohol-soluble protein aqueous solution is 2.0%.

[0020] Furthermore, in S1, the stirring time is 0.5-2 h, preferably 0.5-1.5 h, and more preferably 1 h.

[0021] Furthermore, in S1, the precipitation method used is anti-solvent precipitation.

[0022] Alternatively, in the above preparation method, in step S2, the mass-volume concentration of the OSA starch aqueous solution is 1.5% to 2.5%.

[0023] Preferably, the mass-volume concentration of the OSA starch aqueous solution is 1.8% to 2.2%.

[0024] More preferably, the mass-volume concentration of the OSA starch aqueous solution is 2.0%.

[0025] Furthermore, in S2, the stirring time is 0.5-2 h, preferably 0.5-1.5 h, and more preferably 1 h.

[0026] Alternatively, in the above preparation method, in step S3, the mass ratio of the alcohol-OSA starch binary nanodispersion to the alcohol-OSA starch is (5-15):1.

[0027] Preferably, the mass ratio of the prolysin to the OSA starch is (8-12):1.

[0028] More preferably, the mass ratio of the prolysin to the OSA starch is 10:1.

[0029] Furthermore, in S3, the stirring conditions are 400-1000 rpm for 1-3 hours.

[0030] Preferably, in S3, the stirring conditions are stirring at 600 rpm for 2 hours.

[0031] Alternatively, in the above preparation method, in step S4, the mass ratio of the prolysin to the Tween-20 is (1-10):1.

[0032] Preferably, the mass ratio of the prolysin to the Tween-20 is (1-5):1.

[0033] More preferably, the mass ratio of the prolysin to the Tween-20 is 1:1.

[0034] Furthermore, in S4, the step of freeze-drying the alcohol-OSA starch-Tween-20 ternary composite Pickering particle dispersion to prepare alcohol-OSA starch-Tween-20 ternary composite Pickering particles is also included.

[0035] In a second aspect, the present invention also provides alcohol-OSA starch-Tween-20 ternary composite Pickering particles prepared by the preparation method described in the first aspect above, wherein the ternary composite Pickering particles are nanoparticles.

[0036] Alternatively, in the above-mentioned ternary composite Pickering particles, the particle size of the nanoparticles is 300~400nm, and the zeta potential value of the nanoparticles is -20~-30 mV.

[0037] In addition to the above three aspects, the present invention also provides a Pickering emulsion comprising the Pickering particles described in the second aspect above, wherein the preparation method of the Pickering emulsion comprises the following steps: adding the Pickering particles described in the second aspect above to water, stirring until fully dissolved, adding coconut oil, and preparing the emulsion by ultrasonication.

[0038] Preferably, the stirring time is 15-45 min, more preferably, the stirring time is 30 min.

[0039] Furthermore, the ultrasound method involved 35% amplitude, 2 minutes of ultrasound, 3 seconds on, and 7 seconds off.

[0040] In a fourth aspect, the present invention also provides the non-therapeutic use of the ternary compound pickerine granules described in the second aspect or the pickerine emulsion described in the third aspect, the use including:

[0041] (1) Application in the preparation of carriers loaded with active ingredients; or

[0042] (2) Application in improving the stability of active ingredients.

[0043] Compared with the prior art, the beneficial effects of the present invention are:

[0044] This invention constructs ternary composite Pickering granules and their emulsions of zein-OSA starch-Tween-20 under different concentrations of Tween-20, solving the problems of instability of the zein-OSA starch composite system and easy stratification and flocculation during storage. By adjusting the proportion of Tween-20 in the ternary composite system, the stability of the zein-OSA starch-Tween-20 ternary composite Pickering granules and their emulsions is improved. Attached Figure Description

[0045] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 Particle size of ternary composite particles formed by different mass percentages of Tween-20. Different proportions represent ternary composite particles formed by different mass percentages of Tween-20 and zein-OSA starch. In the figure, if the letters on any two bars are the same, it indicates that the difference between them is not statistically significant; if the letters on any two bars are different, it indicates that the difference between them is statistically significant, and p < 0.05.

[0047] Figure 2 Zeta potential (ζ-potential) of ternary composite particles formed by different mass proportions of Tween-20. Different proportions represent ternary composite particles formed by different mass proportions of Tween-20 and zein-OSA starch. In the figure, when the letters on any two bars are the same, it indicates that the difference between them is not statistically significant; when the letters on any two bars are different, it indicates that the difference between them is statistically significant, and p < 0.05.

[0048] Figure 3 Interfacial tension of ternary composite particles formed with different mass percentages of Tween-20. Different proportions represent ternary composite particles formed with different mass percentages of Tween-20 and zein-OSA starch.

[0049] Figure 4 Contact angle of ternary composite particles formed by different mass percentages of Tween-20. Different proportions represent ternary composite particles formed by different mass percentages of Tween-20 and zein-OSA starch.

[0050] Figure 5 Particle sizes of mono-, binary, and ternary Pickering emulsions. Specifically, Zein: mono-picklerin emulsion composed of zein; Zein+OSA: binary Pickering emulsion composed of zein and OSA starch; Zein+1:1: binary Pickering emulsion composed of zein and Tween-20 at a mass ratio of 1:1; Zein+OSA+1:1: ternary Pickering emulsion composed of zein, OSA starch, and Tween-20 at a mass ratio of 1:1. In the figure, if the letters on any two bars are the same, it indicates that the difference between them is not statistically significant; if the letters on any two bars are different, it indicates that the difference between them is statistically significant, and p < 0.05.

[0051] Figure 6Particle size of mono-, binary, and ternary Pickering emulsions stored at room temperature for 7 days. Specifically: Zein: mono-picklerin emulsion of zein; Zein+OSA: binary Pickering emulsion of zein and OSA starch; Zein+1:1: binary Pickering emulsion of zein and Tween-20 in a 1:1 mass ratio; Zein+OSA+1:1: ternary Pickering emulsion of zein, OSA starch, and Tween-20 in a 1:1 mass ratio. In the figure, if the letters on any two bars are the same, it indicates that the difference between them is not statistically significant; if the letters on any two bars are different, it indicates that the difference between them is statistically significant, and p < 0.05.

[0052] Figure 7 The stability at 24°C of mono-, binary, and ternary Pickering emulsions was evaluated. Specifically, Zein was a mono-type Pickering emulsion composed of zein; Zein+OSA was a binary Pickering emulsion composed of zein and OSA starch; Zein+1:1 was a binary Pickering emulsion composed of zein and Tween-20 at a mass ratio of 1:1; and Zein+OSA+1:1 was a ternary Pickering emulsion composed of zein, OSA starch, and Tween-20 at a mass ratio of 1:1.

[0053] Figure 8 Zeta potentials of mono-, binary, and ternary Pickering emulsions. Zein: mono-pickled zein emulsion; Zein+OSA: binary pickering emulsion composed of zein and OSA starch; Zein+1:1: binary pickering emulsion composed of zein and Tween-20 at a mass ratio of 1:1; Zein+OSA+1:1: ternary pickering emulsion composed of zein, OSA starch, and Tween-20 at a mass ratio of 1:1. In the figure, if the letters on any two bars are the same, the difference between them is not statistically significant; if the letters on any two bars are different, the difference between them is statistically significant (p < 0.05).

[0054] Figure 9 Interfacial tension of unary and binary nanoparticles. Among them, Zein: unary zein particles; Zein+OSA: binary particles composed of zein and OSA starch; Zein+1:1: binary particles composed of zein and Tween-20 in a mass ratio of 1:1.

[0055] Figure 10: Contact angle of unary and binary nanoparticles. Wherein: Zein: unary zein particles; Zein+OSA: binary particles composed of zein and OSA starch; Zein+1:1: binary particles composed of zein and Tween-20 in a mass ratio of 1:1. Detailed Implementation

[0056] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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. Unless otherwise specified, the materials and reagents used are commercially available.

[0057] In this invention, the unit of mass w in the mass-volume ratio w / v is mg, and the unit of volume v is mL.

[0058] Example:

[0059] (I) Experimental Methods:

[0060] 1. Dissolve 4 g of zein in a 75% (v / v) ethanol / water solution and stir continuously for 1 hour to ensure complete dissolution. Adjust the pH of the zein solution to 8.0 using a 1 mol / L NaOH standard solution. Then, under continuous stirring, add the zein nanoparticles dropwise to 200 mL of the aqueous solution using an antisolvent method to form zein nanoparticles. Remove the ethanol from the system by rotary evaporation, while simultaneously concentrating the particle concentration to 200 mL. The final mass concentration of the zein solution in the system is 2.0% (w / v).

[0061] 2. Dissolve OSA starch in deionized water and stir continuously for 1 h until completely dissolved. Adjust the pH of the solution to 8.0 using 1 mol / L NaOH standard solution, and then bring the volume to a final concentration of 2.0% (w / v) with deionized water. Add 20 mL of 2% (w / v) OSA starch solution dropwise to 200 mL of the zein solution prepared in Part 1, and stir for 1 h to ensure thorough mixing of OSA starch and zein, thus preparing zein-OSA starch binary nanoparticles. The final ratio of zein to OSA starch is 10:1. Take a portion of the aqueous dispersion and pre-freeze it at -80℃ for 12 h, then freeze-dry it under vacuum (-40℃) for 48 h. Place the freeze-dried sample in a desiccator for later use.

[0062] 3. Different amounts of Tween-20 were added to the zein-OSA starch dispersion at ratios of 20:1, 10:1, 5:1, 2:1, and 1:1 (mass ratio of zein to Tween-20). The mixture was then stirred at 600 rpm for 2 hours to prepare zein-OSA starch-Tween-20 ternary nanoparticles with different Tween-20 concentrations. The samples were stored in liquid form at 4°C for further analysis. A portion of the samples was pre-frozen at -80°C for 12 hours, followed by vacuum freeze-drying (-40°C) for 48 hours. The freeze-dried samples were then stored in a desiccator for later use.

[0063] 4. Preparation of Pickering emulsions: 0.2 g of freeze-dried mono-, binary, and ternary composite nanoparticles were added to 20 mL of deionized water and stirred for 30 min until fully dissolved. 2 mL of coconut oil was added, and the emulsions were prepared by sonication (35% amplitude, sonication for 2 min, on for 3 s, off for 7 s). The prepared mono-, binary, and ternary Pickering emulsions were scanned at 25 °C every 10 min for 24 h to determine their 24-hour storage stability. The emulsions were then stored at room temperature for 7 days for subsequent analysis.

[0064] 5. The mono-, binary, and ternary Pickering particles and emulsions, as well as the Pickering emulsion stored for 7 days, were diluted to 1 mg / mL with deionized water. The zeta potential and particle size of the nanoparticles and the zeta potential of the Pickering emulsion were measured using a Zetasizer (Nano-ZS90, Malvern, UK). The particle size of the Pickering emulsion was determined using a Mastersizer 3000 laser particle size analyzer. The results are expressed as the volume-weighted average diameter D[4, 3]. Each sample was analyzed three times, and all measurements were performed at 25°C.

[0065] 6. Determination of Contact Angle and Interfacial Tension: The contact angle of the composite particles was determined using an Attention Theta Flow contact angle meter. In a quartz sample cell, the high-precision injection system needle was inserted below the oil interface, and deionized water was dropped onto the surface of a circular tablet. The shape and changes of the droplet were recorded using a high-speed camera. The dynamic interfacial tension of the droplet was measured using an optical contact angle meter at 25 ± 0.5℃. The oil-water interfacial tension between the oil phase and the composite particle solution was measured using the pendant drop method. The dynamic changes in tension over a certain period of time were recorded until tension equilibrium was reached.

[0066] 7. Based on the previous measurement results, the optimal ratio of Tween-20 was screened and determined. Then, Tween-20 in the optimal ratio was combined with zein to construct a binary composite particle system. The characteristics of the prepared binary composite particles and the relevant performance indicators of the Pickering emulsion stabilized by them were measured and analyzed.

[0067] (II) Experimental Results:

[0068] Particle size directly reflects the size and aggregation of particles, and is one of the important indicators. For example... Figure 1 As shown, within a certain range, the particle size of the ternary composite particles gradually increases with the increase of the mass proportion of Tween-20, with the largest particle size observed when the mass ratio of zein to Tween-20 is 1:1. The results indicate that Tween-20 can aggregate and bind with zein-OSA starch binary particles to form zein-OSA starch-Tween-20 ternary composite particles. Furthermore, within a certain range, the higher the content of Tween-20, the more it binds with the zein-OSA starch binary particles, thus forming a larger ternary composite. These large-sized Pickering particles effectively prevent droplet fusion by constructing stronger steric hindrance at the droplet interface.

[0069] Zeta potential, as a key parameter for measuring the electrical properties of particle surfaces, can accurately reflect the strength of the repulsive forces between particles. For example... Figure 2 As shown, the zeta potentials of the ternary composite particles are all negative. Within a certain range, the zeta potential of the ternary composite particles does not change significantly with increasing Tween-20 mass fraction. However, the absolute value of the zeta potential reaches its maximum when the mass ratio of zein to Tween-20 is 1:1. The results indicate that an appropriate amount of Tween-20 can synergistically interact with zein and OSA starch to form a ternary composite structure that significantly enhances the negative charge on the particle surface, thereby maximizing the electrostatic stability of the system.

[0070] Interfacial tension (IFT) directly characterizes the adsorption kinetics and efficiency of surfactants at the oil-water interface. A decrease in IFT value stems from interfacial adsorption, which directly enhances the kinetic stability of the emulsion by weakening the tendency for droplets to fuse. For example... Figure 3As shown, with the increase of the mass proportion of Tween-20, the interfacial tension of the ternary composite particles generally decreases. The interfacial tension is lowest when the mass ratio of zein to Tween-20 is 1:1. The results indicate that increasing the mass proportion of Tween-20 helps improve the ability of the ternary composite particles to reduce interfacial tension. Furthermore, the particles with a zein-to-Tween-20 mass ratio of 1:1 exhibit the lowest interfacial tension in the final equilibrium state, indicating that the particles have optimal interfacial activity at this ratio.

[0071] As a core factor in evaluating the ability of solid particles to stabilize Pickering emulsions, the wettability (i.e., hydrophilic-lipophilic balance) of the particles directly affects their contact angle and anchoring depth at the oil-water interface, ultimately determining their emulsion stabilization efficiency. A commonly used quantitative indicator of this characteristic is the three-phase contact angle (θ) of the particles at the oil-water interface. When the three-phase contact angle of the particles approaches 90°, the particles exhibit optimally balanced hydrophilic and oleophilic properties. This property enhances the anchoring effect of the particles at the oil-water interface, thereby forming a more efficient and stable Pickering emulsion and improving overall stabilization efficiency. Figure 4 As shown, with the increase of the mass proportion of Tween-20, the contact angle of the ternary composite particles gradually decreases and approaches 90°. The contact angle is 94.2° when the mass ratio of zein to Tween-20 is 2:1. When the mass ratio is further increased to 1:1, the contact angle begins to be less than 90°. Based on Figure 3 A comprehensive analysis of interfacial tension and three-phase contact angles revealed that the composite particles exhibited the best interfacial performance and emulsifying properties when the mass ratio of zein to Tween-20 was 1:1. Therefore, a mass ratio of 1:1 was determined to be the optimal ratio for preparing ternary composite particles, and further research was conducted.

[0072] To clarify the individual contributions and synergistic effects of Tween-20 and OSA starch in the construction of zein-based Pickering emulsions, zein mono-component, zein-OSA starch binary, and zein-Tween-20 binary Pickering particles and emulsions were prepared based on the optimal mass ratio (1:1), and compared with the optimal ternary composite particles and emulsions. Figure 5 As shown, the particle size of both binary and ternary Pickering emulsions with added Tween-20 and OSA starch was significantly smaller than that of the unary Pickering emulsion, with the ternary Pickering emulsion exhibiting the smallest particle size. The results indicate that the addition of Tween-20 and OSA starch significantly optimized the size and uniformity of the emulsion droplets, and this finer, more stable microstructure directly led to a significant improvement in the macroscopic stability of the emulsion. After storage at room temperature for 7 days, the particle size of the Pickering emulsion was as follows... Figure 6As shown, the particle size of the mono-component and zein-OSA starch binary Pickering emulsions increased significantly after 7 days of storage compared to their initial state. However, the particle size of the zein-Tween-20 binary and ternary Pickering emulsions showed only minor changes after 7 days of storage, and their values ​​were significantly lower than those of the mono-component and zein-OSA starch binary Pickering emulsions. The ternary Pickering emulsion exhibited the smallest particle size. These results indicate a clear synergistic effect between zein, OSA starch, and Tween-20. The ternary particles constructed by the synergistic interaction of these three components can simultaneously utilize electrostatic stability and steric hindrance mechanisms to efficiently inhibit droplet aggregation, thereby obtaining Pickering emulsions with smaller, more concentrated droplet distribution and significantly enhanced storage stability.

[0073] The stability index (TSI) is a key parameter for rapidly and quantitatively assessing the overall stability of emulsions; its value directly reflects the stability of the system. A higher TSI value indicates greater instability, while a lower TSI value indicates greater stability. Figure 7 As shown, the instability of zein-based Pickering emulsions gradually increased over time. The overall instability of binary and ternary Pickering emulsions with added Tween-20 and OSA starch was lower than that of the mono-based Pickering emulsion, with the ternary Pickering emulsion exhibiting the lowest overall instability. These results indicate that adding Tween-20 and OSA starch to form a zein-OSA starch-Tween-20 ternary Pickering emulsion significantly improves the stability of the system.

[0074] like Figure 8 As shown, the zeta potentials of all zein-based Pickering emulsions were negative. Furthermore, the absolute values ​​of the zeta potentials of the binary and ternary Pickering emulsions formed by adding Tween-20 and OSA starch were significantly higher than those of the mono-based Pickering emulsion. The ternary Pickering emulsion exhibited the highest absolute zeta potential value, exceeding 30 mV, indicating good stability of the emulsion particles and inhibiting particle aggregation. These results suggest that Tween-20 and OSA starch synergistically adsorb onto the surface of zein particles, significantly increasing the interfacial charge density and thus enhancing the electrostatic repulsion between droplets. This is one of the key mechanisms by which the ternary emulsion achieves high stability.

[0075] Figure 9 The interfacial tension between unary and binary nanoparticles is related to... Figure 3Analysis of the interfacial tension of ternary composite particles with a Tween-20 mass ratio of 1:1 revealed that the interfacial tension values ​​of both binary and ternary composite particles containing Tween-20 and OSA starch were generally lower than those of the unary particles, with the ternary composite particles exhibiting the lowest overall interfacial tension. These results indicate a synergistic effect between Tween-20 and OSA starch on the surface activity of the composite particles, a key driving force for the successful construction and stabilization of a zein-based Pickering emulsion.

[0076] Figure 10 The contact angle between unary and binary nanoparticles, and... Figure 4 Contact angle analysis of ternary composite particles with a Tween-20 mass ratio of 1:1 revealed that the contact angles of both binary and ternary composite particles containing Tween-20 and OSA starch were smaller than those of the unary particles. The ternary composite particles had the closest contact angle to 90°, forming the most stable oil-in-water emulsion system. These results indicate that both Tween-20 and OSA starch can enhance the hydrophilicity of the composite particles by reducing their contact angle, effectively promoting adsorption and anchoring at the oil-water interface. This lays the foundation for constructing a more stable zein-based Pickering emulsion system.

[0077] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several modifications or equivalent substitutions can be made to the technical solution without departing from the principle of the present invention, and these modifications or equivalent substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a ternary composite Pickering granule of alcohol-OSA starch-Tween-20, characterized in that: The preparation method includes the following steps: S1. Mix prolysin with ethanol / water solution, stir, adjust the pH of the system to 8.0 to obtain prolysin ethanol / water solution, then add the solution dropwise to water under continuous stirring to form prolysin nanoparticles, remove ethanol from the system, and concentrate the system to obtain prolysin aqueous solution; S2. Mix OSA starch with water, stir, and adjust the pH of the system to 8.0 to obtain an OSA starch aqueous solution; S3. The OSA starch aqueous solution prepared in S2 is added dropwise to the alcohol-soluble protein aqueous solution prepared in S1, and the mixture is stirred to fully mix the OSA starch and alcohol-soluble protein to obtain an alcohol-soluble protein-OSA starch binary nano-dispersion. S4. Add Tween-20 to the dispersion prepared in S3, stir, and obtain alcohol-soluble protein-OSA starch-Tween-20 ternary composite Pickering particles.

2. The preparation method according to claim 1, characterized in that: The prolysin is zein, and the OSA starch is derived from corn starch.

3. The preparation method according to claim 1, characterized in that: In S1, the ethanol / water solution is 70%~85% ethanol / water solution by volume percentage, and the mass-volume concentration of the alcohol-soluble protein aqueous solution is 1.5% g / mL~2.5% g / mL.

4. The preparation method according to claim 1, characterized in that: In S2, the mass-volume concentration of the OSA starch aqueous solution is 1.5% g / mL to 2.5% g / mL.

5. The preparation method according to claim 1, characterized in that: In S3, in the alcohol-OSA starch binary nanodispersion, the mass ratio of the alcohol-OSA starch to the alcohol is (5-15):

1.

6. The preparation method according to claim 1, characterized in that: In S4, the mass ratio of the prolysin to the Tween-20 is (1-10):

1.

7. Pickering granules, prepared by the method according to any one of claims 1 to 6, characterized in that: The ternary composite Pickering particles are nanoparticles.

8. The ternary composite Pickering particles according to claim 7, characterized in that: The nanoparticles have a particle size of 300~400 nm and a zeta potential of -20~-30 mV.

9. A Pickering emulsion, characterized in that: The Pickering emulsion comprises the Pickering particles as described in claim 7 or claim 8, and the preparation method of the Pickering emulsion comprises the following steps: adding the Pickering particles as described in claim 7 or claim 8 to water, stirring until fully dissolved, adding coconut oil, and preparing the emulsion by ultrasound.

10. The non-therapeutic use of the ternary compound pickerine granules of claim 7 or claim 8 or the pickerine emulsion of claim 9, characterized in that: The applications include: (1) Application in the preparation of carriers loaded with active ingredients; or (2) Application in improving the stability of active ingredients.

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