A stable pigment preparation, a method of preparation

Abstract

This invention belongs to the field of food additives and discloses a stable pigment preparation and its preparation method. The pigment preparation includes the following raw materials: natural pigment, composite carrier, composite biological antioxidant, stabilizer, dispersant, maltodextrin, trehalose, fructooligosaccharide, and plasticizer. The composite carrier is a ternary covalent complex prepared by amidation reaction of pectin, chitosan oligosaccharide, and ferulic acid. The stabilizer is hydroxypropyl-β-cyclodextrin grafted with L-arginine after activation. This invention solves the problem of single function of pigment preparations through the synergistic effect of composite carrier, stabilizer, and composite biological antioxidant, and also achieves the integrated effect of protection, dispersion, and controlled release, improving the stability, dispersibility, controlled release, and safety of the preparation, and effectively expanding the application scope of natural pigments in food, medicine, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of food additive technology, specifically relating to a stable pigment preparation and its preparation method. Background Technology

[0002] Natural pigments, derived from natural plants, animals, or microorganisms, possess advantages such as high safety, natural color, and certain nutritional and health benefits, making them widely used in food, medicine, and cosmetics. However, natural pigments inherently suffer from structural instability. During production, storage, and application, they are susceptible to degradation and discoloration due to external environmental factors (such as high temperature, light, acidic conditions, and oxidation), leading to reduced pigment content and poorer coloring effects, severely limiting their industrial application. Furthermore, natural pigments have poor dispersibility and tend to aggregate in food processing systems, affecting color uniformity and further accelerating degradation.

[0003] Existing technologies typically employ methods such as carrier encapsulation and the addition of antioxidants to modify natural pigments and improve their stability. Currently, commonly used carriers are primarily single polymeric carriers (such as gum arabic and maltodextrin). These carriers have limited function, providing only preliminary protection to the pigments through simple physical encapsulation, failing to form an effective dual protective barrier, and exhibiting limited resistance to external factors such as high temperature, light, and oxidation. Furthermore, existing technologies often add auxiliary agents to improve pigment dispersibility; however, conventional auxiliary agents only provide simple dispersion and cannot form a synergistic effect with the carrier and pigment molecules, making it difficult to further fix the pigment molecules, thus still resulting in pigment loss and insufficient stability. Summary of the Invention

[0004] To address the shortcomings mentioned in the background art, the present invention aims to provide a stable pigment preparation and its preparation method. Through the synergistic combination of composite carrier, stabilizer, and composite bio-antioxidant, the problem of single function of pigment preparation is solved, and the integrated effect of protection, dispersion, and controlled release is achieved, thereby improving the stability, dispersibility, controlled release, and safety of the preparation and effectively expanding the application scope of natural pigments in food, medicine, and other fields.

[0005] The objective of this invention can be achieved through the following technical solutions: A stable pigment preparation comprises the following raw materials in parts by weight: 8-12 parts natural pigment, 40-45 parts composite carrier, 18-24 parts composite biological antioxidant, 2-4 parts stabilizer, 3-4 parts dispersant, 7-9 parts maltodextrin, 4-5 parts trehalose, 1-1.5 parts fructooligosaccharide, and 1-2 parts plasticizer. The composite carrier is a ternary covalent complex prepared by amidation reaction of pectin, chitosan oligosaccharide and ferulic acid; the stabilizer is L-arginine grafted onto hydroxypropyl-β-cyclodextrin after activation.

[0006] Preferably, the natural pigment is a natural pigment containing phenolic hydroxyl groups, and the natural pigment is one or more of anthocyanins, betalains, curcumin and shikonin.

[0007] Preferably, the compound biological antioxidant is a mixture of rosmarinic acid, gallic acid, and tea polyphenols in a mass ratio of 2:1:0.5; The dispersant is a mixture of polyglycerol fatty acid ester and sucrose fatty acid ester in a mass ratio of 1.5:1; The plasticizer is a mixture of polyethylene glycol 400 and glyceryl monostearate in a mass ratio of 1:1.

[0008] Preferably, the method for preparing the composite carrier includes the following steps: A. Dissolve pectin in purified water to prepare a 5wt% pectin solution, adjust the pH to 6.5 with citric acid, add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, stir at room temperature for 20-40 minutes to complete the activation of pectin carboxyl groups; B. Add chitosan oligosaccharide to the activated pectin solution, heat to 55℃, stir at a constant temperature for 1.5~2.5h, and keep the pH stable at 6.5 to form a pectin-chitosan oligosaccharide binary covalent complex solution. C. Add ferulic acid to the above binary complex solution, adjust the pH to 7.0, heat to 60℃, stir for 3-5 hours, sonicate for 10 minutes every hour, after the reaction is complete, freeze dry the reaction solution and pulverize it through an 80-mesh sieve to obtain the composite carrier.

[0009] Preferably, the mass ratio of pectin, chitosan oligosaccharide and ferulic acid is 3:2.2:0.8, the amount of 1-ethyl-(3-dimethylaminopropyl)carbodiimide is 5% of the mass of pectin, and the amount of N-hydroxysuccinimide is 3% of the mass of pectin.

[0010] Preferably, the method for preparing the stabilizer includes the following steps: (1) Dissolve hydroxypropyl-β-cyclodextrin in anhydrous ethanol to prepare a 10wt% hydroxypropyl-β-cyclodextrin solution, add triethylamine, stir evenly, heat to 45℃, and stir at a constant temperature for 10~20min to complete the hydroxyl activation of hydroxypropyl-β-cyclodextrin. (2) Slowly add L-arginine to the above activation solution, heat to 55℃, and stir at a constant temperature for 4~6 hours; (3) After the reaction is complete, the solution is distilled under reduced pressure to remove anhydrous ethanol. The remaining product is dissolved in pure water, filtered to remove insoluble matter, freeze-dried and pulverized through an 80-mesh sieve to obtain the stabilizer.

[0011] Preferably, the mass ratio of hydroxypropyl-β-cyclodextrin to L-arginine is 8:2.

[0012] The preparation of a stable pigment formulation includes the following steps: S1. Dissolve the composite carrier in purified water to prepare a carrier solution with a concentration of 8wt%. Add a stabilizer, stir to dissolve, and then ultrasonically disperse for 10-20 min. Dissolve the natural pigment in purified water and slowly add it dropwise to the carrier solution. Adjust the pH to 5.0-5.5 with citric acid. Stir at room temperature for 0.5-1.5 h. Finally, add the composite biological antioxidant, heat to 45℃, and stir at a constant temperature for 1.5-2.5 h to obtain the composite carrier composite system. S2. Add dispersant to the composite carrier system, stir at 25℃ for 0.5~1.5h, ultrasonically disperse for 10~20min, and use the antisolvent precipitation method to add 2~3 times the volume of the composite system of antisolvent in a gradient dropwise. Stir until a homogeneous suspension is formed, centrifuge the suspension to collect the precipitate, and wash it 2~3 times with anhydrous ethanol and pure water to completely remove the antisolvent and unbound components, and obtain composite carrier nanoparticles. S3. Mix maltodextrin, trehalose, fructooligosaccharides, and plasticizer, dissolve them in purified water to prepare a 12wt% mixed solution, heat to 60℃, add composite carrier nanoparticles to the above mixed solution, ultrasonically disperse for 15~25min to form a coating system, dry the coating system using a spray drying process, cool to room temperature and pass through a 100-mesh sieve to obtain a stable pigment preparation.

[0013] Preferably, the antisolvent is a mixture of anhydrous ethanol, acetone and propylene glycol in a volume ratio of 3:1:0.5; The gradient addition method involves first adding 50% at a rate of 1 mL / min, stirring for 20-40 min, and then adding the remaining amount at a rate of 0.5 mL / min.

[0014] Preferably, the spray drying inlet air temperature is 180℃, the outlet air temperature is 80℃, the feed rate is 4~6mL / min, and the atomization pressure is 0.2~0.4MPa.

[0015] The beneficial effects of this invention are: This invention utilizes a composite carrier to anchor pigment molecules through both electrostatic interactions and hydrogen bonds. A stabilizer assists in anchoring the pigment molecules via the composite carrier, limiting their conformational changes and aggregation. A bio-composite antioxidant is introduced to form π-π stacking and a hydrogen bond network with the pigment molecules, simultaneously forming a phenolic acid synergistic antioxidant unit with ferulic acid. This scavenges free radicals and chelates metal ions, inhibiting pigment oxidative degradation through a chemical pathway. Uniform nanoparticles of 150-220 nm are formed through antisolvent nanoprecipitation, with an outer glassy protective layer formed by maltodextrin and trehalose, reducing the direct effects of water, oxygen, and light on the pigment. This preparation method not only stabilizes the pigment but also endows the food system with additional functions such as antioxidant, prebiotic, and antibacterial properties. Compared with traditional microencapsulation, it improves pigment retention and antioxidant activity.

[0016] The composite carrier of this invention is a pectin-chitosan oligosaccharide-ferulic acid ternary covalent complex. Through amidation graft copolymerization, a stable three-dimensional network structure is formed, providing a dual protective barrier for pigment molecules. This effectively resists the effects of external environmental factors such as high temperature, light, acidic conditions, and oxidation, significantly reducing pigment degradation and significantly improving pigment retention during production, storage, and application. The ferulic acid in the ternary covalent complex forms a four-fold phenolic acid synergistic antioxidant unit with the composite bio-antioxidant, further enhancing the antioxidant protection effect and effectively extending the shelf life of the formulation. Simultaneously, the ternary covalent complex exhibits excellent dispersibility; combined with ultrasonic dispersion technology, it ensures uniform dispersion of pigment molecules in the formulation system, effectively preventing pigment aggregation.

[0017] The stabilizer of this invention is hydroxypropyl-β-cyclodextrin grafted with L-arginine. Utilizing the cavity structure of hydroxypropyl-β-cyclodextrin and the guanidinyl group in the L-arginine molecule, it forms multiple bonds with natural pigments containing phenolic hydroxyl groups through hydrogen bonds or electrostatic interactions. This assists the composite carrier in anchoring pigment molecules, restricting conformational changes and aggregation of pigment molecules, and further enhancing pigment anchoring stability. The hydrophilic group of L-arginine can form hydrogen bonds with the composite biological antioxidant, further enhancing the stability of the tetraphenolic acid synergistic antioxidant unit and indirectly inhibiting pigment oxidative degradation. Simultaneously, its alkalinity can regulate the pH stability of the anchoring system, providing a suitable environment for the binding of pigments and the carrier without affecting subsequent nanoparticle formation. The grafted functionalized derivative retains the advantages of hydroxypropyl-β-cyclodextrin, such as low hygroscopicity and no hemolytic irritation. At the same time, by leveraging the biocompatibility of L-arginine, it improves the dispersibility and compatibility of the formulation in food systems, avoids formulation aggregation, and does not introduce harmful components, meeting the safety requirements of the food industry. It can also help improve the biocompatibility of the formulation. In addition, as a food-grade functional amino acid, L-arginine can give the formulation a slight nutritional fortification effect. In synergy with chitosan oligosaccharide and fructooligosaccharide, it can further enrich the prebiotic-related additional functions of the formulation, which is in line with the development trend of health food, without affecting the color and stability of the pigment itself.

[0018] All components used in this invention are food-grade and contain no harmful reagents. Through mild processes such as freeze-drying and spray drying, the risk of reagent residue is effectively avoided, ensuring the safety of the formulation and meeting food-grade product standards. At the same time, the various steps in the preparation process are coordinated and interconnected, the parameters are easy to control and highly repeatable, no complex and precision equipment is required, and it is easy to scale up industrial production, reduce production costs, and solve the shortcomings of existing processes that are difficult to apply on a large scale.

[0019] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 A method for preparing a composite carrier includes the following steps: A. Dissolve 15g of pectin in 275mL of purified water to prepare a 5wt% pectin solution. Adjust the pH to 6.5 with citric acid. Add 0.75g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.45g of N-hydroxysuccinimide. Stir at room temperature for 30min to complete the activation of pectin carboxyl groups. B. Add 11g of chitosan oligosaccharide to the activated pectin solution, heat to 55℃, stir at a constant temperature for 2 hours, and keep the pH stable at around 6.5 to form a pectin-chitosan oligosaccharide binary covalent complex solution. C. Add 4g of ferulic acid to the above binary composite solution, adjust the pH to 7.0, heat to 60℃, stir for 4h, sonicate for 10min every 1h, after the reaction is complete, freeze dry the reaction solution and pulverize it through an 80-mesh sieve to obtain the composite carrier.

[0022] Example 2 A method for preparing a stabilizer includes the following steps: (1) Dissolve 16g of hydroxypropyl-β-cyclodextrin in 182mL of anhydrous ethanol to prepare a hydroxypropyl-β-cyclodextrin solution with a concentration of 10wt%. Add 10g of triethylamine, stir evenly, heat to 45℃, and stir at a constant temperature for 15min to complete the hydroxyl activation of hydroxypropyl-β-cyclodextrin. (2) Slowly add 4g of L-arginine to the above activation solution, heat to 55℃, and stir at a constant temperature for 5h. (3) After the reaction is complete, the solution is distilled under reduced pressure to remove anhydrous ethanol. The remaining product is dissolved in pure water, filtered to remove insoluble matter, freeze-dried and pulverized through an 80-mesh sieve to obtain the stabilizer.

[0023] Example 3 A stable pigment formulation comprises the following raw materials in parts by weight: 8 parts anthocyanins, 45 parts composite carrier, 10 parts rosmarinic acid, 6 parts gallic acid, 2 parts tea polyphenols, 4 parts stabilizer, 1.8 parts polyglycerol fatty acid ester and 1.2 parts sucrose fatty acid, 9.0 parts maltodextrin, 4.0 parts trehalose, 1.5 parts fructooligosaccharides, 0.5 parts polyethylene glycol 400, and 0.5 parts glyceryl monostearate; the composite carrier is prepared in Example 1, and the stabilizer is prepared in Example 2.

[0024] The preparation method of the above-mentioned stable pigment formulation includes the following steps: S1. Dissolve the composite carrier in purified water to prepare a carrier solution with a concentration of 8wt%. Add a stabilizer, stir to dissolve, and then ultrasonically disperse for 20 min. Dissolve anthocyanins in purified water and slowly add them dropwise to the carrier solution. Adjust the pH to 5.0 with citric acid. Stir at room temperature for 1.5 h. Finally, add the composite biological antioxidant, heat to 45℃, and stir at a constant temperature for 1.5 h to obtain the composite carrier composite system. S2. Add a dispersant to the composite carrier system, stir at 25℃ for 1.5 h, and ultrasonically disperse for 10 min. Use the antisolvent precipitation method to add 3 times the volume of the composite system of antisolvent in a gradient. The antisolvent is anhydrous ethanol, acetone and propylene glycol in a volume ratio of 3:1:0.5. First, add 50% at 1 mL / min and stir for 20 min. Then add the remaining 0.5 mL / min and stir until a homogeneous suspension is formed. Centrifuge the suspension to collect the precipitate, and wash it 2-3 times with anhydrous ethanol and pure water to completely remove the antisolvent and unbound components, and obtain the composite carrier nanoparticles. S3. Maltodextrin, trehalose, fructooligosaccharides, and plasticizer are mixed and dissolved in purified water to prepare a 12wt% mixed solution. The solution is heated to 60°C, and the composite carrier nanoparticles are added to the mixed solution. The mixture is ultrasonically dispersed for 25 minutes to form a coating system. The coating system is then dried using a spray drying process with an inlet air temperature of 180°C, an outlet air temperature of 80°C, a feed rate of 4 mL / min, and an atomization pressure of 0.4 MPa. After cooling to room temperature, the mixture is passed through a 100-mesh sieve to obtain the stable pigment preparation.

[0025] Example 4 A stable pigment formulation comprises the following raw materials in parts by weight: 12 parts betaine, 40 parts composite carrier, 15 parts rosmarinic acid, 7 parts gallic acid, 2 parts tea polyphenols, 2 parts stabilizer, 2.4 parts polyglycerol fatty acid ester, 1.6 parts sucrose fatty acid, 7.0 parts maltodextrin, 5.0 parts trehalose, 1.0 part fructooligosaccharide, 1 part polyethylene glycol 400, and 1 part glyceryl monostearate; wherein the composite carrier is prepared in Example 1, and the stabilizer is prepared in Example 2.

[0026] The preparation method of the above-mentioned stable pigment formulation includes the following steps: S1. Dissolve the composite carrier in purified water to prepare a carrier solution with a concentration of 8wt%. Add a stabilizer, stir to dissolve, and then ultrasonically disperse for 10 min. Dissolve betalain in purified water and slowly add it dropwise to the carrier solution. Adjust the pH to 5.5 with citric acid. Stir at room temperature for 0.5 h. Finally, add the composite biological antioxidant, heat to 45℃, and stir at a constant temperature for 2.5 h to obtain the composite carrier composite system. S2. Add a dispersant to the composite carrier system, stir at 25℃ for 0.5 h, and ultrasonically disperse for 20 min. Use the antisolvent precipitation method to add 2 times the volume of the composite system of antisolvent in a gradient. The antisolvent is anhydrous ethanol, acetone and propylene glycol in a volume ratio of 3:1:0.5. First, add 50% at 1 mL / min and stir for 40 min. Then add the remaining 0.5 mL / min and stir until a homogeneous suspension is formed. Centrifuge the suspension to collect the precipitate, and wash it 2-3 times with anhydrous ethanol and pure water to completely remove the antisolvent and unbound components, and obtain the composite carrier nanoparticles. S3. Maltodextrin, trehalose, fructooligosaccharides, and plasticizer are mixed and dissolved in purified water to prepare a 12wt% mixed solution. The solution is heated to 60°C, and the composite carrier nanoparticles are added to the mixed solution. The mixture is ultrasonically dispersed for 15 minutes to form a coating system. The coating system is then dried using a spray drying process with an inlet air temperature of 180°C, an outlet air temperature of 80°C, a feed rate of 6 mL / min, and an atomization pressure of 0.2 MPa. After cooling to room temperature, the solution is passed through a 100-mesh sieve to obtain the stable pigment preparation.

[0027] Example 5 A stable pigment formulation comprises the following raw materials in parts by weight: 10 parts curcumin, 42 parts composite carrier, 12 parts rosmarinic acid, 6 parts gallic acid, 3 parts tea polyphenols, 3 parts stabilizer, 2.1 parts polyglycerol fatty acid ester, 1.4 parts sucrose fatty acid, 8 parts maltodextrin, 4.5 parts trehalose, 1.2 parts fructooligosaccharides, 0.75 parts polyethylene glycol 400, and 0.75 parts glyceryl monostearate; the composite carrier is prepared in Example 1, and the stabilizer is prepared in Example 2.

[0028] The preparation method of the above-mentioned stable pigment preparation includes the following steps: S1. Dissolve the composite carrier in purified water to prepare a carrier solution with a concentration of 8wt%. Add a stabilizer, stir to dissolve, and then ultrasonically disperse for 15 min. Dissolve curcumin in purified water and slowly add it dropwise to the carrier solution. Adjust the pH to 5.5 with citric acid, stir at room temperature for 1 h, and finally add the composite biological antioxidant. Heat to 45℃ and stir at a constant temperature for 1 h to obtain the composite carrier composite system. S2. Add a dispersant to the composite carrier system, stir at 25℃ for 1 hour, and ultrasonically disperse for 150 minutes. Use the antisolvent precipitation method to add 3 times the volume of the composite system of antisolvent in a gradient. The antisolvent is anhydrous ethanol, acetone and propylene glycol in a volume ratio of 3:1:0.5. First, add 50% at 1 mL / min and stir for 30 minutes. Then add the remaining 0.5 mL / min and stir until a homogeneous suspension is formed. Centrifuge the suspension to collect the precipitate, and wash it 2-3 times with anhydrous ethanol and pure water to completely remove the antisolvent and unbound components, and obtain the composite carrier nanoparticles. S3. Maltodextrin, trehalose, fructooligosaccharides, and plasticizer are mixed and dissolved in purified water to prepare a 12wt% mixed solution. The solution is heated to 60°C, and the composite carrier nanoparticles are added to the mixed solution. The mixture is ultrasonically dispersed for 20 minutes to form a coating system. The coating system is then dried using a spray drying process with an inlet air temperature of 180°C, an outlet air temperature of 80°C, a feed rate of 5 mL / min, and an atomization pressure of 0.3 MPa. After cooling to room temperature, the mixture is passed through a 100-mesh sieve to obtain the stable pigment preparation.

[0029] Comparative Example 1 A stable pigment formulation comprises the following raw materials in parts by weight: 10 parts curcumin, 42 parts gum arabic, 12 parts rosmarinic acid, 6 parts gallic acid, 3 parts tea polyphenols, 3 parts stabilizer, 2.1 parts polyglycerol fatty acid ester, 1.4 parts sucrose fatty acid, 8 parts maltodextrin, 4.5 parts trehalose, 1.2 parts fructooligosaccharides, 0.75 parts polyethylene glycol 400, and 0.75 parts glyceryl monostearate; wherein the stabilizer is prepared in Example 2.

[0030] The preparation method of the above-mentioned stable pigment preparation is the same as that in Example 5, except that in step S1, the composite carrier is replaced with an equal amount of gum arabic.

[0031] Comparative Example 2 A stable pigment formulation comprises the following raw materials in parts by weight: 10 parts curcumin, 42 parts composite carrier, 12 parts rosmarinic acid, 6 parts gallic acid, 3 parts tea polyphenols, 3 parts stabilizer, 2.1 parts polyglycerol fatty acid ester, 1.4 parts sucrose fatty acid, 8 parts maltodextrin, 4.5 parts trehalose, 1.2 parts fructooligosaccharides, 0.75 parts polyethylene glycol 400, and 0.75 parts glyceryl monostearate; the composite carrier is prepared in Example 1, and the stabilizer is prepared in Example 2.

[0032] The preparation method of the above-mentioned stable pigment preparation is the same as that in Example 5, except that no stabilizer is added to the composite carrier composite system in step S1.

[0033] Performance testing The performance of the stable pigment preparations prepared in Example 5, Comparative Example 1, and Comparative Example 2 was tested. Comparative Examples 1 and 2 used the same raw materials as Comparative Example 5, except that Comparative Example 1 lacked the composite carrier prepared in this invention and replaced it with an equal amount of gum arabic as the carrier, and Comparative Example 2 lacked the stabilizer prepared in this invention. Therefore, the performance of Example 5 and Comparative Examples 1 and 2 was compared to characterize the effect of the composite carrier and stabilizer in improving the stability of the pigment preparation.

[0034] 1. Basic performance testing (1) The curcumin content was determined by ultraviolet-visible spectrophotometry. 0.0100 g of curcumin standard was accurately weighed, dissolved in anhydrous ethanol, and diluted to 100 mL to prepare a standard stock solution with a concentration of 100 μg / mL. 0.2, 0.4, 0.6, 0.8, and 1.0 mL of the standard stock solution were respectively diluted to 10 mL with anhydrous ethanol to obtain standard working solutions with concentrations of 2, 4, 6, 8, and 10 μg / mL. Using anhydrous ethanol as a blank control, the absorbance of each standard working solution was measured at a wavelength of 425 nm. The curcumin concentration was used as the horizontal axis for measurement. Plot a standard curve with absorbance as the ordinate and coordinates to obtain the regression equation. Weigh 0.1000g of each sample from the experimental group, Comparative Example 1, and Comparative Example 2 into 50mL centrifuge tubes, add 20mL of anhydrous ethanol, and sonicate for 30min (200W, 25℃). Centrifuge (5000r / min, 10min) and collect the supernatant. Repeat the extraction twice, combine the supernatants, and dilute to 50mL with anhydrous ethanol. After shaking, filter and measure the absorbance of the filtrate at 425nm. Calculate the curcumin content in the samples based on the standard curve. (2) The particle size of the stable pigment preparation was determined by a nanoparticle size analyzer. 0.05g of each of the three groups of samples were dissolved in 10mL of pure water and ultrasonically dispersed for 10min (power 200W) to prepare a homogeneous suspension. The suspension was injected into the sample cell of the particle size analyzer, the test temperature was set to 25℃, and the test was performed 3 times. The average particle size and particle size distribution width (PDI) were recorded. The appearance of the sample (color and clumping) was observed with the naked eye. The results are shown in Table 1 below.

[0035] Table 1. Basic performance data of stable pigment formulations

[0036] 2. Aging resistance test Three groups of samples were placed under the following four accelerated aging conditions and cultured for 15 days. The curcumin content was measured and the retention rate was calculated. At the same time, the initial curcumin content of the samples was measured as a blank control. (1) High temperature conditions: 45℃ constant temperature incubator, sealed and stored; (2) Light conditions: 25℃, natural light (light intensity 4000lx), sealed and stored; (3) Acidic conditions: Dissolve the sample in a citrate-sodium citrate buffer solution with pH=3.0 and store it in a sealed container at a constant temperature of 25℃; (4) Oxidation conditions: Dissolve the sample in purified water containing 0.1% H2O2 and store it at a constant temperature of 25℃ in a sealed container.

[0037] The results are shown in Table 2 below.

[0038] Table 2. Test results of the aging resistance of stable pigment formulations

[0039] 3. Storage stability test Three groups of samples were sealed and packaged, and stored in a constant temperature and humidity chamber at 25℃ and 60% relative humidity for 6 months. The curcumin retention rate was measured at 0, 1, 2, 3, and 6 months, and the appearance of the samples (color, clumping) was observed to evaluate the long-term storage stability. The results are shown in Table 3 below.

[0040] Table 3. Data on storage stability test results of stable pigment formulations

[0041] As shown in Tables 1-3, Example 5 exhibited the smallest average particle size, the lowest PDI, and good uniformity. Comparative Example 1, due to the replacement of the carrier with conventional gum arabic, showed a significant increase in particle size and decreased uniformity, indicating that the ternary covalent complex possesses superior dispersibility and carrier performance. Comparative Example 2, lacking a stabilizer, had a slightly larger particle size than the experimental group, resulting in a decrease in uniformity. Example 5 showed significantly higher curcumin retention rates under various accelerated aging conditions and long-term storage compared to the two comparative examples, demonstrating that the pectin-chitosan oligosaccharide-ferulic acid ternary covalent complex, as a carrier, effectively protects curcumin from degradation by high temperature, light, acidity, and oxidation. Furthermore, the addition of hydroxypropyl-β-cyclodextrin grafted with L-arginine further enhances the stability of curcumin and reduces its degradation.

[0042] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A stable pigment formulation, characterized in that, The ingredients include the following parts by weight: 8-12 parts natural pigment, 40-45 parts composite carrier, 18-24 parts composite biological antioxidant, 2-4 parts stabilizer, 3-4 parts dispersant, 7-9 parts maltodextrin, 4-5 parts trehalose, 1-1.5 parts fructooligosaccharide, and 1-2 parts plasticizer. The composite carrier is a ternary covalent complex prepared by amidation reaction of pectin, chitosan oligosaccharide and ferulic acid; the stabilizer is L-arginine grafted onto hydroxypropyl-β-cyclodextrin after activation.

2. The stable pigment formulation according to claim 1, characterized in that, The natural pigment is a natural pigment containing phenolic hydroxyl groups, and the natural pigment is one or more of anthocyanins, betalains, curcumin and shikonin.

3. The stable pigment formulation according to claim 1, characterized in that, The compound biological antioxidant is a mixture of rosmarinic acid, gallic acid, and tea polyphenols in a mass ratio of 2:1:0.

5. The dispersant is a mixture of polyglycerol fatty acid ester and sucrose fatty acid ester in a mass ratio of 1.5:1; The plasticizer is a mixture of polyethylene glycol 400 and glyceryl monostearate in a mass ratio of 1:

1.

4. The stable pigment formulation according to claim 1, characterized in that, The method for preparing the composite carrier includes the following steps: A. Dissolve pectin in purified water to prepare a 5wt% pectin solution, adjust the pH to 6.5 with citric acid, add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, stir at room temperature for 20-40 minutes to complete the activation of pectin carboxyl groups; B. Add chitosan oligosaccharide to the activated pectin solution, heat to 55℃, stir at a constant temperature for 1.5~2.5h, and keep the pH stable at 6.5 to form a pectin-chitosan oligosaccharide binary covalent complex solution. C. Add ferulic acid to the above binary composite solution, adjust the pH to 7.0, heat to 60°C, stir for 3-5 hours, sonicate for 10 minutes every hour, after the reaction is complete, freeze dry the reaction solution and pulverize it through an 80-mesh sieve to obtain the composite carrier.

5. The stable pigment formulation according to claim 6, characterized in that, The mass ratio of pectin, chitosan oligosaccharide, and ferulic acid is 3:2.2:0.8, the amount of 1-ethyl-(3-dimethylaminopropyl)carbodiimide is 5% of the pectin mass, and the amount of N-hydroxysuccinimide is 3% of the pectin mass.

6. The stable pigment formulation according to claim 1, characterized in that, The method for preparing the stabilizer includes the following steps: (1) Dissolve hydroxypropyl-β-cyclodextrin in anhydrous ethanol to prepare a 10wt% hydroxypropyl-β-cyclodextrin solution, add triethylamine, stir evenly, heat to 45℃, and stir at a constant temperature for 10~20min to complete the hydroxyl activation of hydroxypropyl-β-cyclodextrin. (2) Slowly add L-arginine to the above activation solution, heat to 55℃, and stir at a constant temperature for 4~6 hours; (3) After the reaction is complete, the solution is distilled under reduced pressure to remove anhydrous ethanol. The remaining product is dissolved in pure water, filtered to remove insoluble matter, freeze-dried and pulverized through an 80-mesh sieve to obtain the stabilizer.

7. The stable pigment formulation according to claim 6, characterized in that, The mass ratio of hydroxypropyl-β-cyclodextrin to L-arginine is 8:

2.

8. The method for preparing the stable pigment formulation according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Dissolve the composite carrier in purified water to prepare a carrier solution with a concentration of 8wt%. Add a stabilizer, stir to dissolve, and then ultrasonically disperse for 10-20 min. Dissolve the natural pigment in purified water and slowly add it dropwise to the carrier solution. Adjust the pH to 5.0-5.5 with citric acid. Stir at room temperature for 0.5-1.5 h. Finally, add the composite biological antioxidant, heat to 45℃, and stir at a constant temperature for 1.5-2.5 h to obtain the composite carrier composite system. S2. Add dispersant to the composite carrier system, stir at 25℃ for 0.5~1.5h, ultrasonically disperse for 10~20min, and use the antisolvent precipitation method to add 2~3 times the volume of the composite system of antisolvent in a gradient dropwise. Stir until a homogeneous suspension is formed, centrifuge the suspension to collect the precipitate, and wash it 2~3 times with anhydrous ethanol and pure water to completely remove the antisolvent and unbound components, and obtain composite carrier nanoparticles. S3. Mix maltodextrin, trehalose, fructooligosaccharides, and plasticizer, dissolve them in purified water to prepare a 12wt% mixed solution, heat to 60°C, add composite carrier nanoparticles to the above mixed solution, ultrasonically disperse for 15-25 minutes to form a coating system, dry the coating system using a spray drying process, cool to room temperature and pass through a 100-mesh sieve to obtain the stable pigment preparation.

9. The method for preparing the stable pigment formulation according to claim 8, characterized in that, The antisolvent is a mixture of anhydrous ethanol, acetone and propylene glycol in a volume ratio of 3:1:0.5; The gradient addition first adds 50% at 1 mL / min, stirring for 20-40 min, and then adds the remainder at 0.5 mL / min.

10. The method for preparing the stable pigment formulation according to claim 8, characterized in that, The spray dryer has an inlet air temperature of 180℃, an outlet air temperature of 80℃, a feed rate of 4~6mL / min, and an atomization pressure of 0.2~0.4MPa.

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