Preparation method and application of zein-citrus pectin nanoparticles loaded with galangin

Abstract

The invention relates to the technical field of food processing, in particular to a preparation method and application of zein-citrus pectin nanoparticles loaded with galangin. The preparation method comprises the following steps: providing a zein solution, and carrying out first mixing treatment on galangin powder and the zein solution to obtain a galangin-zein solution; dropwise adding the galangin-zein solution into a continuously stirred water phase, and concentrating to remove ethanol, so as to obtain a galangin-loaded zein nanoparticle dispersion liquid; providing a citrus pectin solution, carrying out second mixing treatment on the citrus pectin solution and the zein nanoparticle dispersion liquid loaded with galangin, and then carrying out post-treatment to obtain the zein-citrus pectin nanoparticles loaded with galangin, the nanoparticles are applied to the sauced products for the first time, the heterocyclic amine content in the sauced meat products is effectively reduced, and the safety of the sauced meat products is improved.

Description

Technical Field

[0001] This application belongs to the field of food processing technology, and in particular relates to a method for preparing zein-citrus pectin nanoparticles loaded with high galangin and their application. Background Technology

[0002] Heterocyclic amines are a class of polycyclic aromatic compounds with mutagenic and carcinogenic properties, often formed during the high-temperature cooking of meat, fish, and other raw materials rich in animal protein. To date, more than 25 heterocyclic amines have been isolated and identified, among which β-carboline heterocyclic amines, mainly Harman and Norharman, are widely distributed in various food systems and are the main types of heterocyclic amines in braised and marinated low-temperature meat products.

[0003] Braised and stewed meat products are a traditional category of meat products that occupy an important place in Chinese cuisine. Besides being commonly found in home cooking and catering, their industrial production has also increased with the rise of the ready-to-cook food industry. The cooking of braised and stewed meat products generally does not involve high temperatures, around 100°C, but requires prolonged heating and the use of various seasonings (such as soy sauce, salt, sugar, and cooking wine) and spices. Soy sauce not only contains abundant free amino acids and reducing sugars, precursors of heterocyclic amines, but also a certain amount of β-carboline intermediates such as tetrahydro-β-carboline (THβC) and end products. Therefore, the addition of soy sauce during the processing of braised and stewed meat products can significantly promote the formation of β-carboline heterocyclic amines, and the level is not negligible. Current technologies for inhibiting the formation of heterocyclic amines in braised and stewed meat products are limited. The addition of spices can effectively reduce the formation of heterocyclic amines; the main inhibitory components are considered to be phytochemicals in spices, especially flavonoids. However, a large portion of the flavonoids in spices are hydrophobic flavonoids, such as galangin, the main component of galangal. Galangin has excellent antioxidant capacity and in vivo physiological activities (such as anti-inflammatory and anti-cancer activities), but its strong hydrophobicity and extremely low solubility in aqueous solutions limit its application potential in various fields, including its use in brine-containing systems such as braised meat products to inhibit the formation of heterocyclic amines.

[0004] Although zein, pectin, and galangin have all been shown to possess certain antioxidant or heterocyclic amine inhibition potential, current technologies lack a synergistic solution that can effectively integrate the heterocyclic amine inhibition potential of these natural components and overcome the water solubility bottleneck of galangin. This prevents the achievement of efficient and stable heterocyclic amine inhibition in aqueous systems such as braised meat products. Therefore, there is an urgent need to develop a new technological solution that can improve the dispersibility and applicability of galangin in aqueous food systems through nano-encapsulation technology, and synergistically utilize the inhibitory effects of zein, pectin, and galangin to effectively reduce the heterocyclic amine content in braised meat products. Summary of the Invention

[0005] The purpose of this application is to provide a method for preparing zein-citrus pectin nanoparticles loaded with galangin and their application, aiming to solve the problem that galangin has poor solubility and dispersibility in aqueous solution in the prior art, and cannot be used effectively.

[0006] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a method for preparing zein-citrus pectin nanoparticles loaded with high levels of galangin, comprising the following steps: A zein solution is provided. Galangin powder and zein solution are first mixed to obtain galangin-zein solution. Galangin-zein solution was added dropwise to an aqueous phase stirred at 700-800 rpm, and then stirred for 5-7 minutes before concentration to obtain a dispersion of galangin-loaded zein nanoparticles. A citrus pectin solution is provided. The citrus pectin solution and a dispersion of zein nanoparticles loaded with high galangin are subjected to a second mixing treatment, followed by post-treatment, to obtain zein-citrus pectin nanoparticles loaded with high galangin.

[0007] In some embodiments, the method for preparing a zein solution includes: dissolving zein in an ethanol solution with a volume percentage of 75%-85% to obtain a zein solution with a zein concentration of 15-25 mg / mL.

[0008] In some embodiments, the method for preparing citrus pectin solution includes: dissolving citrus pectin powder in an aqueous solution and adjusting the pH to 4.0 to obtain a citrus pectin aqueous solution with a final pectin concentration of 0.5-1.5 mg / mL.

[0009] In some embodiments, the rotation speed of the first mixing process is 600-800 rpm, and the time is 30-35 minutes.

[0010] In some embodiments, the final concentration of galangin in the galangin-zein solution is 1.0-2.0 mg / mL.

[0011] In some embodiments, the volume ratio of galangin-zein solution to water is 1:3-1:5.

[0012] In some embodiments, the concentration step includes: rotating the cylinder at a speed of 1000-1500 rpm for 30-35 minutes under vacuum conditions to remove ethanol, and replenishing the volume lost by evaporation with pure water.

[0013] In some embodiments, the step of providing a citrus pectin solution and subjecting the citrus pectin solution and the zein nanoparticle dispersion loaded with high levels of galangin to a second mixing treatment includes: The volume ratio of citrus pectin solution to zein nanoparticle dispersion loaded with high galangin is 1:1. The second mixing process is carried out at a speed of 1000-1200 rpm for 10-30 minutes.

[0014] In some embodiments, the post-processing includes centrifugation at 3000-3500 rpm for 10-15 minutes.

[0015] Secondly, this application provides a zein-citrus pectin nanoparticle loaded with high galangin prepared by the above method, with a particle size of 100-150 nm, a polydispersity index ≤0.3, a zeta potential of -20 to -30 mV, an encapsulation efficiency ≥90%, and a drug loading of 6-8%.

[0016] Thirdly, this application provides a method for preparing braised meat products, wherein the above-mentioned galangin-loaded zein-citrus pectin nanoparticle suspension is added during the braising process, wherein the amount of galangin-loaded zein-citrus pectin nanoparticle suspension added is 25%-50% of the total weight of the braising liquid.

[0017] In some embodiments, after adding a zein-citrus pectin nanoparticle suspension loaded with galangin, the braising process is continued for at least 1 hour.

[0018] Fourthly, this application provides the application of zein-citrus pectin nanoparticles loaded with high levels of galangin in reducing the content of heterocyclic amines in braised meat products.

[0019] The preparation method provided in the first aspect of this application addresses the issue that galangin possesses certain antioxidant potential and the ability to inhibit heterocyclic amine formation, but suffers from poor water solubility. It utilizes zein, whose molecules contain numerous hydrophobic amino acids, exhibiting overall hydrophobicity and the ability to self-assemble into nanoparticles. Furthermore, the hydrophobic regions of this protein can interact with galangin, promoting its loading into the particle interior and protecting galangin from external environmental degradation, thus enhancing its stability. This method also improves the dispersibility of galangin in aqueous solutions. By encapsulating citrus pectin on the surface of zein, the nanoparticles are modified and stabilized, synergistically enhancing the encapsulation effect of galangin with zein. The preparation process is simple, conducive to industrial production, and applicable to various fields.

[0020] The second aspect of this application provides a zein-citrus pectin nanoparticle loaded with high galangin prepared by the above method. It has excellent performance, stable properties, remains stable in a variety of physicochemical environments, and can adapt to different processing environments.

[0021] The third aspect of this application provides a method for preparing braised meat products, which innovatively applies zein-citrus pectin nanoparticles loaded with high galangin to the braised meat product system. This method can simultaneously and effectively inhibit heterocyclic amines in both the braised meat and the braising broth. Moreover, the assembly raw materials are all natural food raw materials, which is safe, efficient, and low-cost, thus broadening the application scenarios of nanoparticles that encapsulate bioactive components. The application of galangin-loaded zein-citrus pectin nanoparticles in reducing heterocyclic amine content in braised meat products, provided in the fourth aspect of this application, effectively improves the dispersibility of galangin in aqueous systems and increases its utilization in aqueous solutions while reducing the required dosage, thus helping to reduce the heterocyclic amine content in braised meat products. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, 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.

[0023] Figure 1 This application describes the preparation method of zein / pectin nanoparticles encapsulated with galangin, as provided in Example 1, and its application in the braising process of braised mutton to reduce heterocyclic amine content.

[0024] Figure 2 The attached figures show the field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) images of the nanoparticle suspension prepared according to Example 1 of this application.

[0025] Figure 3 This is a performance analysis of the zein / pectin nanoparticles encapsulated with galangin provided in Example 2 of this application.

[0026] Figure 4 This is an analytical graph showing the content of free and total (free + bound) β-carboline heterocyclic amines in the braising liquid and braised meat provided in the embodiments of this application. Detailed Implementation

[0027] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0028] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0029] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0030] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0031] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0032] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as µg, mg, g, or kg.

[0033] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0034] The first aspect of this application provides a method for preparing zein-citrus pectin nanoparticles loaded with high levels of galangin, comprising the following steps: Step S01. Provide a zein solution, and perform a first mixing treatment on galangin powder and zein solution to obtain a galangin-zein solution; Step S02. Add the galangin-zein solution dropwise to the aqueous phase stirred at 700-800 rpm, then continue stirring for 5-7 minutes, and then concentrate to obtain a dispersion of galangin-loaded zein nanoparticles. Step S03. Provide a citrus pectin solution, and perform a second mixing treatment on the citrus pectin solution and the dispersion of zein nanoparticles loaded with high galangin, followed by post-treatment to obtain zein-citrus pectin nanoparticles loaded with high galangin.

[0035] The preparation method provided in the first aspect of this application addresses the issue that galangin has certain antioxidant potential and can inhibit the formation of heterocyclic amines, but it has poor water solubility. It utilizes zein, whose molecules contain many hydrophobic amino acids and are generally hydrophobic, allowing it to self-assemble into nanoparticles. Furthermore, the hydrophobic regions of this protein can interact with galangin, promoting its loading into the particle interior, protecting galangin from external environmental degradation and improving its stability. It also helps improve the dispersibility of galangin in aqueous solutions. By coating the surface of zein with citrus pectin, the nanoparticles are modified and stabilized, synergistically enhancing the encapsulation effect of galangin with zein. This simple preparation process is conducive to industrial production and can be applied in various fields.

[0036] Step S01. Provide a zein solution, and perform a first mixing treatment on galangin powder and zein solution to obtain a galangin-zein solution.

[0037] In some embodiments, the method for preparing a zein solution includes: dissolving zein in an ethanol solution with a volume percentage of 75%-85% to obtain a zein solution with a zein concentration of 15-25 mg / mL.

[0038] In some embodiments, the method for preparing citrus pectin solution includes: dissolving citrus pectin powder in an aqueous solution and adjusting the pH to 4.0 to obtain a citrus pectin aqueous solution with a final pectin concentration of 0.5-1.5 mg / mL.

[0039] In some embodiments, the rotation speed of the first mixing treatment is 600-800 rpm, and the time is 30-35 minutes. The rotation speed and time of the first mixing treatment are limited to ensure that the galangin powder can be completely dissolved in the zein solution.

[0040] In some embodiments, the final concentration of galangin in the galangin-zein solution is 1.0-2.0 mg / mL.

[0041] Step S02. The galangin-zein solution is added dropwise to the aqueous phase stirred at 700-800 rpm, and then stirred for another 5-7 minutes before concentration to obtain a dispersion of galangin-loaded zein nanoparticles. In this step, the galangin-zein solution is added dropwise to water at a specific rotation speed to ensure the formation of nanoparticles.

[0042] A stirring speed of 700-800 rpm ensures that each drop of added organic solution is quickly and evenly dispersed in the aqueous phase, avoiding particle aggregation and uneven growth caused by excessively high local concentrations. This is essential for obtaining monodisperse, small-sized nanoparticles. If the stirring speed is too low, it will lead to uneven mixing, forming large particles or even precipitation.

[0043] The "drop-by-drop addition" method is equivalent to introducing a large amount of supersaturated "raw material" into the system in batches and small doses. This causes the system to periodically generate a controllable instantaneous supersaturation state during the drop-addition process, preferentially promoting "nucleation" rather than "growth," thus facilitating the formation of small and uniform particles. If poured in rapidly, extremely high supersaturation will be generated instantaneously, causing nucleation and growth to occur violently and simultaneously, easily leading to uneven particle size and a wider distribution range.

[0044] After the addition is complete, the nucleation process of the particles in the system is basically finished. Continue stirring for 5-7 minutes to promote the full diffusion of the organic solvent into the aqueous phase, so that the particle morphology and size gradually stabilize and the system reaches a temporary equilibrium state, providing a stable dispersion system for the subsequent concentration steps.

[0045] In some embodiments, the volume ratio of galangin-zein solution to water is 1:3-1:5.

[0046] In some embodiments, the concentration step includes: rotating the cylinder at a speed of 1500-1600 rpm for 30-35 minutes under vacuum conditions to remove ethanol, and replenishing the volume lost by evaporation with pure water.

[0047] In step S03, a citrus pectin solution is provided, and the citrus pectin solution and the dispersion of zein nanoparticles loaded with high galangin are subjected to a second mixing treatment, followed by post-treatment to obtain zein-citrus pectin nanoparticles loaded with high galangin.

[0048] In some embodiments, the step of providing a citrus pectin solution and subjecting a second mixing treatment of the citrus pectin solution and a dispersion of zein nanoparticles loaded with high levels of galangin includes: The volume ratio of citrus pectin solution to zein nanoparticle dispersion loaded with high galangin is 1:1. The second mixing process is carried out at a speed of 1000-1200 rpm for 10-30 minutes.

[0049] In some embodiments, post-processing includes centrifuging at 3000-3500 rpm for 10-15 minutes to remove large particles or aggregates.

[0050] In some specific embodiments, a zein protein loaded with high levels of galangin... A method for preparing citrus pectin nanoparticles, the specific preparation method including: (1) Preparation of zein solution: zein was dissolved in 75%-85% (v / v) ethanol to obtain a zein solution with a concentration of 15-25 mg / mL.

[0051] (2) Preparation of galangin and zein complex solution: Galangin powder was added to the zein solution and stirred at 600-800 rpm for 30-35 minutes to ensure that galangin was fully dissolved and had sufficient hydrophobic interaction with zein, so as to obtain a galangin and zein mixed solution with a final concentration of 1.0-2.0 mg / mL.

[0052] (3) Preparation of citrus pectin solution: Dissolve citrus pectin powder in aqueous solution and adjust pH to 4.0 to obtain citrus pectin aqueous solution with a final pectin concentration of 0.5-1.5 mg / mL.

[0053] (4) Preparation of galangin-loaded zein nanoparticles: Under continuous stirring at 700-800 rpm, the galangin-zein composite solution obtained in (2) was added dropwise to pure water (pH 4.0) at a volume ratio of 1:3-1:5, and stirred continuously for 5-7 minutes. Then, the prepared nanoparticle suspension was concentrated under vacuum at a speed of 1000-1500 rpm for 30-35 minutes to remove ethanol, and the volume lost by evaporation was replenished with pure water (pH 4.0).

[0054] (5) Preparation of zein-citrus pectin nanoparticles loaded with galangin: The nanoparticle dispersion obtained in (4) was mixed with an equal volume of citrus pine gum solution (0.5-1.5 mg / mL, pH 4.0) and stirred at 900-1100 rpm for 10-30 minutes to ensure that the zein-loaded galangin nanoparticles and citrus pectin have sufficient electrostatic interaction and are coated on the surface of the nanoparticles to form a shell of nanoparticles.

[0055] (6) Removal of large particles: Finally, the formed nanoparticle suspension is centrifuged at 3000-3500 rpm for 10-15 minutes to remove aggregates and large particles, and freshly prepared zein-citrus pectin nanoparticle suspension loaded with galangin is obtained.

[0056] The second aspect of this application provides a zein-citrus pectin nanoparticle loaded with galangin prepared by the above method, with a particle size of 100-150 nm, a polydispersity index ≤0.3, a zeta potential of -20 to -30 mV, an encapsulation efficiency ≥90%, and a drug loading of 6-8%.

[0057] The second aspect of this application provides a zein-citrus pectin nanoparticle loaded with galangin prepared by the above method. It has excellent performance, stable properties, remains stable in a variety of physicochemical environments, and can adapt to different processing environments.

[0058] The third aspect of this application provides a method for preparing braised meat products, wherein the above-mentioned zein-citrus pectin nanoparticle suspension loaded with galangin is added during the braising process, wherein the amount of zein-citrus pectin nanoparticle suspension added is 25%-50% of the total weight of the braising liquid.

[0059] The third aspect of this application provides a method for preparing braised meat products, which innovatively applies zein-citrus pectin nanoparticles loaded with high galangin to the braised meat product system. This method can simultaneously achieve effective inhibition of heterocyclic amines in both the braised meat and the braising broth. Moreover, the assembly raw materials are all natural food raw materials, which is safe, efficient, and low-cost, thus broadening the application scenarios of nanoparticles that encapsulate bioactive components.

[0060] In some embodiments, after adding a zein-citrus pectin nanoparticle suspension loaded with galangin, the braising process is continued for at least 1 hour.

[0061] In some specific embodiments, zein-citrus pectin nanoparticles loaded with high levels of galangin are applied to the braising process of traditional braised products to reduce the formation of heterocyclic amines in braised meat and braising broth; the specific steps include: (1) Blanching. Add 1200-1800 parts of water by weight to a pot. After the water boils, add 20% of the weight of the mutton (pre-cut into pieces of 150±10 g each). Heat on an induction cooker at 2200 W (or high) for 15 minutes. Remove the mutton and rinse it with water to remove the blood foam. Discard the blanching broth.

[0062] (2) Boil over high heat. Add the blanched mutton to another 1200-1800 parts of water, add 0.5-1.0% salt and 1.0-2.0% sugar by weight of water, and heat at 2200 W to a vigorous boiling state for 30 minutes.

[0063] (3) Simmer over low heat. To compensate for the water evaporated during the high-heat cooking stage, add fresh water to restore the initial liquid level. After boiling, adjust the power of the induction cooker to 500 W to achieve a gentle boil and cook for 1 hour.

[0064] (4) Braising. Add light soy sauce and dark soy sauce, each accounting for 3% of the total weight of water, and then add 25%~50% of the total weight of braising liquid, consisting of zein-citrus pectin nanoparticle suspension loaded with galangin. Continue braising for 1 hour.

[0065] (5) Finished product. After cooking, remove the braised mutton to obtain the finished braised mutton. In some embodiments, the raw meat is sheep hind leg meat.

[0066] In some embodiments, the pot is a deep-bottomed soup pot, and the water added should cover the mutton.

[0067] In some embodiments, the heating device is an induction cooker with an adjustable power range of greater than 500-2200 W, in order to achieve the adjustment between vigorous boiling and simmering.

[0068] The fourth aspect of this application provides the application of zein-citrus pectin nanoparticles loaded with high levels of galangin in reducing the heterocyclic amine content in braised meat products.

[0069] The fourth aspect of this application provides the application of galangin-loaded zein-citrus pectin nanoparticles in reducing the heterocyclic amine content in braised meat products. In this application, by efficiently loading galangin onto nanoparticles, the dispersibility of galangin in the aqueous system can be effectively improved, its utilization in aqueous solution can be increased, and the required amount can be reduced, which is beneficial to reducing the heterocyclic amine content in braised meat products.

[0070] The following description is based on specific embodiments.

[0071] Example 1 (1) Preparation of zein solution: zein was dissolved in 85% (v / v) ethanol to obtain a zein solution with a zein concentration of 20 mg / mL.

[0072] (2) Preparation of galangin and zein complex solution: Galangin powder was added to zein solution and stirred at 800 rpm for 30 minutes to ensure that galangin was fully dissolved and had sufficient hydrophobic interaction with zein, so as to obtain a galangin and zein mixed solution with a final concentration of 2 mg / mL.

[0073] (3) Preparation of citrus pectin solution: Dissolve citrus pectin powder in aqueous solution and adjust pH to 4.0 to obtain citrus pectin aqueous solution with a final pectin concentration of 1.0 mg / mL.

[0074] (4) Preparation of galangin-loaded zein nanoparticles: The galangin-zein composite solution obtained in (2) was added dropwise to pure water (pH 4.0) at a volume ratio of 1:4 while continuously stirring at 800 rpm, and then stirred for 5 minutes. Afterwards, the prepared nanoparticle suspension was concentrated by rotating at 1500 rpm under vacuum for 30 minutes to remove ethanol, and the volume lost by evaporation was replenished with pure water (pH 4.0).

[0075] (5) Preparation of galangin-loaded zein-citrus pectin nanoparticles (hereinafter referred to as nanoparticles): The dispersion of galangin-loaded zein nanoparticles obtained in (4) was mixed with an equal volume of citrus pectin solution (1.0 mg / mL, pH 4.0) and stirred at 1000 rpm for 10 min to ensure that the galangin-loaded zein nanoparticles and citrus pectin have sufficient electrostatic interaction and are coated on the surface of the nanoparticles to form the shell of the nanoparticles.

[0076] (6) Removal of large particles: Finally, the formed nanoparticle suspension is centrifuged at 3000 rpm for 10 minutes to remove aggregates and large particles, and freshly prepared zein-citrus pectin nanoparticle suspension loaded with galangin (hereinafter referred to as nanoparticle suspension).

[0077] Example 2 (1) pH stability: The freshly prepared nanoparticle suspension in Example (1) was adjusted to pH 2, 4, 4.8, 6 and 8 respectively and then allowed to stand for 2 h to evaluate the stability of the nanoparticles under different pH conditions.

[0078] (2) Salt ion concentration stability: The freshly prepared nanoparticle suspension in Example (1) was mixed with an equal volume of 0~400 mM sodium chloride aqueous solution or sodium chloride soy sauce solution (containing 6% light soy sauce and 6% dark soy sauce) to make the final sodium chloride concentration in the system 0, 10, 20, 50, 100, 150, 200 mM, respectively, to evaluate the stability of the nanoparticles under different salt ion concentrations and in different media.

[0079] (3) Heating stability: The freshly prepared nanoparticle suspension in Example (1) was placed in a 100°C water bath and heated for 0, 15, 30, 45, 60, 90 and 120 minutes respectively to evaluate the stability of the nanoparticles under long-term heating at 100°C.

[0080] (4) Storage stability: The freshly prepared nanoparticle suspension in Example (1) was stored in a 4°C refrigerator or in the dark at room temperature. Samples were taken at 0, 2, 3, 6, 12 and 18 days to evaluate the stability of the nanoparticles at different temperatures for different storage times.

[0081] Example 3 (1) Blanching. Take 1500 parts of water by weight and add it to a pot. After the water boils, add 300 g of mutton (pre-cut into pieces of 150±10 g each). Heat the mutton on an induction cooker at 2200 W (or high) for 15 minutes. Remove the mutton and rinse it with water to remove the blood foam. Discard the blanching broth.

[0082] (2) Boil over high heat. Add the blanched mutton to another 1500 parts of water, along with 10 g of salt and 20 g of sugar, and heat at 2200 W to a vigorous boiling state for 30 minutes.

[0083] (3) Simmer over low heat. To compensate for the water evaporated during the high-heat cooking stage, add fresh water to restore the initial liquid level. After boiling, adjust the power of the induction cooker to 500 W to achieve a gentle boil and cook for 1 hour.

[0084] (4) Braising. Add 45 g of light soy sauce and 45 g of dark soy sauce respectively, as well as the freshly prepared nanoparticle suspension in Example 1, accounting for 25% or 50% of the total weight of the brine, and continue braising for 1 hour.

[0085] (5) Finished product. After cooking, the braised mutton was removed to obtain the finished braised mutton, which is ready for analysis. Property Test (1) The nanoparticle suspension prepared in Example 1 was diluted 10 times with pure water at pH 4.0, and the particle size, polydispersity index (PDI) and zeta potential were determined using a NanoBrook particle size and zeta potential analyzer (Brookhaven, USA). The results are shown in Appendix Table 1.

[0086] (2) The content of galangin embedded in the nanoparticles prepared in Example 1 and the mass of the nanoparticles after freeze-drying were determined. The encapsulation efficiency of the nanoparticles for galangin and the drug loading of the nanoparticles were calculated. The results are shown in Appendix Table 1.

[0087] (3) The nanoparticle suspension prepared in Example 1 was observed under field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The results are shown in the appendix. Figure 2 As shown.

[0088] (4) The nanoparticle suspension treated in Example 2 was diluted 10 times with pure water at pH 4.0, and the particle size, polydispersity index (PDI), and zeta potential were determined using a NanoBrook particle size and zeta potential analyzer (Brookhaven, USA). The retention rates of galangin loaded in the nanoparticles were also measured before and after heating at 100°C for 120 minutes, and after storage at 4°C and room temperature for 18 days. The results are shown in the appendix. Figure 3 As shown.

[0089] (5) After pretreatment of the braised mutton obtained in Example 3, the contents of free and bound β-carboline heterocyclic amines in the braised meat were determined, and the contents of free β-carboline heterocyclic amines in the braising liquid were also determined. The results are shown in the appendix. Figure 4 As shown.

[0090] Results Analysis (1) The nanoparticle suspension prepared in Example 1 was diluted 10 times with pure water at pH 4.0, and the particle size, polydispersity index (PDI) and zeta potential were measured. At the same time, the content of galangin embedded in the nanoparticles and the mass of the lyophilized nanoparticles were measured. The encapsulation efficiency of the nanoparticles for galangin and the drug loading of the nanoparticles were calculated. The results are shown in Appendix Table 1.

[0091] The nanoparticles have a diameter of 123.42 ± 0.67 nm, exhibiting a small particle size. The polydispersity index (PDI) is 0.12 ± 0.03, less than 0.3, indicating good dispersibility and uniformity. The zeta potential is -21.81 ± 4.40 mV, indicating that pectin successfully adheres to the nanoparticle surface, causing the originally positively charged nanoparticle core to carry a negative charge. The high absolute value of the zeta potential also indicates good stability of the prepared nanoparticles. The encapsulation efficiency of galangin by the nanoparticles is 96.07 ± 4.09%, indicating that most of the galangin is successfully encapsulated within the nanoparticles. The drug loading is 7.93 ± 0.34%, indicating that the prepared nanoparticles have a high loading capacity for galangin.

[0092] (2) The nanoparticle suspension prepared in Example 1 was observed under field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The results are shown in the appendix. Figure 2 As shown.

[0093] Appendix Figure 2 Image (A) is a field emission scanning electron microscope (FE-SEM) image of the nanoparticles, with accompanying text. Figure 2 (B) is a transmission electron microscope (TEM) image of the nanoparticles. Both images show that the prepared nanoparticles have a uniform and clear spherical structure.

[0094] (3) The nanoparticle suspension treated in Example 2 was diluted 10 times with pure water at pH 4.0, and the particle size, polydispersity index (PDI), and zeta potential were measured. Simultaneously, the retention rate of galangin loaded in the nanoparticles was measured before and after heating at 100°C for 120 minutes, and before and after storage at 4°C and room temperature for 18 days. The results are shown in the appendix. Figure 3 As shown.

[0095] a) pH stability Figure 3 (A) and (B). The nanoparticles only showed significant precipitation at pH 2 and remained stable at pH 4–8, indicating that the nanoparticles are suitable for food processing environments with pH 4–8.

[0096] b) Salt ion concentration stability ( Figure 3(C) and (D). The nanoparticles showed a significant increase in size (661.59 ± 19.37 nm) at a NaCl concentration of 50 mM, and obvious precipitation began to appear from 100 mM NaCl, indicating that the nanoparticles can tolerate NaCl concentrations below 50 mM in aqueous solution. In a soy sauce aqueous solution containing NaCl, the nanoparticles remained highly stable at 200 mM NaCl, indicating that a complex food matrix helps improve the tolerance of nanoparticles to salt ions, resulting in stronger stability and adaptability to actual processing conditions.

[0097] c) Heating stability ( Figure 3 (E) and (F). The nanoparticles exhibited considerable thermal stability at 100 °C, with the particle size increasing only slowly with prolonged heating time. Even after heating at 100 °C for 120 minutes, the nanoparticles still maintained a small particle size (225.14 ± 6.06 nm) and a polydispersity index (0.21), and the retention rate of galangin did not decrease significantly. This indicates that the nanoparticles can be applied to food systems heated at 100 °C for extended periods, and also possess the potential to protect galangin and prevent its thermal degradation.

[0098] d) Storage stability ( Figure 3 (G) and (H). The particle size of the nanoparticles did not change significantly after storage at 4℃ and room temperature for 1–18 days. However, compared to the retention rate of galangin, the retention rate of galangin-loaded nanoparticles after 18 days of storage at 4℃ was 72.62% ± 3.04%, indicating that the nanoparticle suspension should be stored at 4℃ to ensure the stable retention of the loaded galangin within the nanoparticles.

[0099] (4) After pretreatment of the braised mutton obtained in Example 3, the contents of free and total β-carboline heterocyclic amines in the braised meat were determined, and the contents of free β-carboline heterocyclic amines in the braising liquid were also determined. The results are shown in the appendix. Figure 4 As shown.

[0100] After adding nanoparticle suspension to the brine, the formation of β-carboline in both the brine and braised meat was significantly reduced. P <0.05). In the brine, the addition of 25% nanoparticle suspension significantly reduced the formation of free β-carboline in the brine, and the inhibitory effect was not significantly different compared with 50% addition. P >0.05), they are effective against 9H-pyridyl[3,4- b Indole (Norharman) and 1-methyl-9H-pyrido[3,4- bThe inhibition rates of indole (Harman) were 32.00–35.97% and 38.07–39.87%, respectively. In braised meat, the 25% nanoparticle suspension showed the most significant inhibitory effect, with an inhibition rate of 28.24% for Norharman and 26.40% for Harman. For total β-carboline (the sum of free and bound β-carboline), the 50% nanoparticle suspension showed the strongest inhibitory effect, reducing total Norharman and Harman by 41.73% and 55.22%, respectively. In conclusion, adding nanoparticle suspension to the braising liquid can significantly reduce the formation of β-carboline in the braising liquid and braised meat, improving the safety of braised mutton products.

[0101] Table 1

[0102] In summary, the galangin-loaded zein-citrus pectin nanoparticles prepared by the method provided in this application can not only be applied to the proven braising process of braised mutton to reduce the formation of β-carboline heterocyclic amines, but also have potential applications in the production control of braised beef, braised pork, and other braised meat products. They are suitable not only for home and restaurant cooking but also for large-scale industrial production. After braising, the braising liquid containing the nanoparticles can be reused, potentially solving the problem of heterocyclic amine accumulation when the braising liquid is reused. Furthermore, the nanoparticles can potentially be applied to high-temperature meat products, playing a role in delaying the thermal degradation of galangin under high-temperature conditions. The nanoparticles penetrating into meat products may also play a role in the sustained release of galangin after the meat is ingested by the human body, thereby improving the absorption and bioavailability of galangin in the body and exerting its health benefits.

[0103] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing zein-citrus pectin nanoparticles loaded with high levels of galangin, characterized in that, Includes the following steps: A zein solution is provided, and galangin powder is mixed with the zein solution to obtain a galangin-zein solution. Galangin-zein solution was added dropwise to an aqueous phase stirred at 700-800 rpm, and then stirred for 5-7 minutes before concentration to obtain a dispersion of galangin-loaded zein nanoparticles. A citrus pectin solution is provided, and the citrus pectin solution and the dispersion of zein nanoparticles loaded with high galangin are subjected to a second mixing treatment, followed by post-treatment to obtain zein-citrus pectin nanoparticles loaded with high galangin.

2. The method for preparing zein-citrus pectin nanoparticles loaded with high levels of galangin according to claim 1, characterized in that, The method for preparing the zein solution includes: dissolving zein in an ethanol solution with a volume percentage of 75%-85% to obtain a zein solution with a zein concentration of 15-25 mg / mL; and / or, The method for preparing the citrus pectin solution includes: dissolving citrus pectin powder in an aqueous solution and adjusting the pH to 4.0 to obtain a citrus pectin aqueous solution with a final pectin concentration of 0.5-1.5 mg / mL.

3. The method for preparing zein-citrus pectin nanoparticles loaded with high levels of galangin according to claim 1, characterized in that, The first mixing process is carried out at a rotation speed of 600-800 rpm for 30-35 minutes; and / or, In the galangin-zein solution, the final concentration of galangin is 1.0-2.0 mg / mL.

4. The method for preparing zein-citrus pectin nanoparticles loaded with high levels of galangin according to claim 1, characterized in that, The volume ratio of the galangin-zein solution to water is 1:3-1:5; and / or, The concentration step includes: under vacuum conditions, rotating the cylinder at a speed of 1000-1500 rpm for 30-35 minutes to remove ethanol, and replenishing the volume lost by evaporation with pure water.

5. The method for preparing zein-citrus pectin nanoparticles loaded with high levels of galangin according to claim 1, characterized in that, The step of providing a citrus pectin solution and subjecting the citrus pectin solution and the zein nanoparticle dispersion loaded with high galangin to a second mixing treatment includes: The volume ratio of the citrus pectin solution to the zein nanoparticle dispersion loaded with high galangin is 1:

1. The second mixing process is carried out at a speed of 900-1100 rpm for 10-30 minutes.

6. The method for preparing zein-citrus pectin nanoparticles loaded with high levels of galangin according to claim 1, characterized in that, The post-processing includes centrifugation at 3000-3500 rpm for 10-15 minutes.

7. A zein-citrus pectin nanoparticle loaded with galangin, prepared by the preparation method according to any one of claims 1-6, characterized in that, The particle size is 100-150 nm, the polydispersity index is ≤0.3, the zeta potential is -20 to -30 mV, the encapsulation efficiency is ≥90%, and the drug loading is 6-8%.

8. A method for preparing braised meat products, characterized in that, During the braising process, a suspension of zein-citrus pectin nanoparticles loaded with galangin is added, wherein the amount of the suspension of zein-citrus pectin nanoparticles loaded with galangin added is 25%-50% of the total weight of the braising liquid.

9. The preparation method according to claim 8, characterized in that, After adding the zein-citrus pectin nanoparticle suspension loaded with galangin, continue braising for at least 1 hour.

10. The application of the zein-citrus pectin nanoparticles loaded with high galangin as described in claim 7 in reducing the heterocyclic amine content in braised meat products.

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