Gastric acid resistant astaxanthin ester microcapsule and preparation method thereof

Abstract

The invention discloses a gastric acid resistant astaxanthin ester microcapsule and a preparation method thereof, and belongs to the technical field of astaxanthin ester processing and preparation. The preparation method comprises the following steps: dispersing starch octenyl succinate in water, gelatinizing, cooling, mixing with a chitosan solution, adding a sodium chloride solution, and freeze-drying to obtain rigid nanoparticles; dissolving natural astaxanthin ester in the oil phase to obtain astaxanthin ester oil; the preparation method comprises the following steps: dissolving rigid nanoparticles in water, adding astaxanthin ester oil, and shearing to obtain an astaxanthin ester emulsion; and mixing with a wall material solution, and carrying out spray drying to obtain the gastric acid-resistant astaxanthin ester microcapsule. The prepared astaxanthin ester microcapsule has gastric acid resistance stability, degradation of astaxanthin ester in the digestion and absorption process is reduced, more astaxanthin ester reaches the small intestine stage to be absorbed into the body, and the utilization efficiency of astaxanthin is improved. The preparation method is simple in preparation process, does not use a small molecular surfactant in the process, is green and safe, and can be efficiently applied to the field of functional foods.

Description

Technical Field

[0001] This invention belongs to the field of astaxanthin ester processing and preparation technology, specifically relating to an anti-gastric acid astaxanthin ester microcapsule and its preparation method. Background Technology

[0002] Astaxanthin is a carotenoid flavonoid compound found in certain marine organisms, such as fish, shrimp, lobsters, crabs, red yeast, and Haematococcus pluvialis. Astaxanthin has a complex molecular structure and can be classified into free astaxanthin, astaxanthin monoesters, and astaxanthin diesters based on the degree of esterification. The content of free astaxanthin and astaxanthin esters varies depending on the source and extraction process; in its natural state, astaxanthin is mostly present in esterified form. Guillou et al. reported that the contents of free astaxanthin, monoesters, and diesters in processed shrimp shell waste were 5.6%, 18.5%, and 75.9%, respectively. As a good source of natural astaxanthin, astaxanthin esters account for approximately 95% of the total astaxanthin content in Haematococcus pluvialis (of which monoesters account for 70% and diesters account for 25%).

[0003] Astaxanthin possesses numerous health benefits, including reducing the risk of cardiovascular disease, anti-diabetic effects, anti-inflammatory properties, anti-cancer activity, and immune system regulation. Furthermore, astaxanthin is the only carotenoid that can cross the retinal and blood-brain barriers, positively impacting the central nervous system, eyes, and brain. Due to its exceptional antioxidant properties and bioactivity, astaxanthin is widely used as a natural pigment and health ingredient in food, cosmetics, and pharmaceuticals. However, its use in food is limited by its strong hydrophobicity, poor environmental stability (high temperature, light, oxygen, etc.), and low bioavailability. To overcome these limitations, encapsulation technology is used to construct delivery systems to improve the utilization efficiency of astaxanthin.

[0004] Astaxanthin encapsulation and delivery systems mainly include emulsions, nanoparticles, liposomes, and microcapsules. Microcapsule technology, in particular, uses physical and chemical changes to encapsulate active substances within a core material, forming micron- or nanon-sized microcapsules. This effectively isolates the active substance from the external microenvironment, enhancing its stability.

[0005] Patent document CN101439029A relates to a method for preparing microencapsulated astaxanthin using pure gum as the wall material. Under high temperature conditions, astaxanthin is dissolved in soybean oil as the oil phase, and pure gum is used as the main wall material as the aqueous phase. After uniform mixing, the mixture is homogenized at 40 MPa to obtain a stable emulsion, which is then spray-dried to obtain microcapsules. Patent document CN105596314A relates to a method for preparing a highly stable cold-water-soluble natural astaxanthin microcapsule formulation. Astaxanthin oil, an oil-soluble antioxidant, and a water-soluble emulsifier are used as the oil phase, and the wall material, water-soluble antioxidant, and filler are added to purified water as the aqueous phase. After stirring the oil and water, the mixture is ground using a sand mill. Granulation is then performed using a cold spray-starch fluidized bed drying method to obtain the microcapsule formulation. These patents mainly focus on the stability of astaxanthin microcapsules during storage and transportation, neglecting the stability of astaxanthin microcapsules during gastrointestinal digestion after consumption, making it difficult to improve the efficient utilization of astaxanthin ester microcapsules during digestion and absorption. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing an acid-resistant astaxanthin ester microcapsule and its preparation method. This method is green and safe, using rigid nanoparticles instead of small molecule surface actives to give it acid-resistant stability, thereby improving the bioacceptability of astaxanthin ester and greatly expanding its application range and utilization efficiency.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing gastric acid-resistant astaxanthin ester microcapsules, comprising the following steps: (1) Preparation of rigid nanoparticles: Chitosan (CS) was dissolved in an acidic solution and magnetically stirred overnight to obtain a chitosan solution; octenyl succinate starch ester (OS) was dispersed in water to obtain an octenyl succinate starch ester solution, which was gelatinized and cooled, then mixed with the chitosan solution, and sodium chloride solution was added. After freeze-drying, rigid nanoparticles were obtained. Preparation of astaxanthin ester oil: Natural astaxanthin esters are dissolved in the oil phase to obtain astaxanthin ester oil; (2) Preparation of rigid nanoparticle stabilized astaxanthin ester emulsion: The rigid nanoparticles obtained in step (1) are dissolved in water to obtain a rigid nanoparticle solution, the astaxanthin ester oil is added, and the astaxanthin ester emulsion is obtained after shearing. (3) The astaxanthin ester emulsion obtained in step (2) is mixed with the wall material solution and spray-dried to obtain the gastric acid resistant astaxanthin ester microcapsules.

[0008] As a preferred embodiment of the present invention, in step (1), the acidic solution includes an aqueous solution of acetic acid with a concentration of 0.8 to 1.5 wt%, the chitosan solution has a concentration of 10 to 30 g / L, and the octenyl succinic acid starch ester solution has a concentration of 0.1 to 10.0 wt%.

[0009] As a preferred embodiment of the present invention, in step (1), the gelatinization temperature is 85~95℃ and the time is 20~40min; the volume ratio of the gelatinized octenyl succinic acid starch ester solution to the chitosan solution is (0.2~5):1; the concentration of the sodium chloride solution is 0.1~600 mM and the volume ratio of the sodium chloride solution to the chitosan solution is (0.05~1):1; the sodium chloride solution is added to adjust the pH of the system to 2~9 and the mixture is stirred for 30~40min.

[0010] Sodium chloride plays a role in regulating the ionic strength of the solution, affecting the solubility and extension state of polymer chains, and thus regulating the self-assembly kinetics of rigid nanoparticle composites. An appropriate sodium chloride concentration can regulate the stability of the formed nanoparticles.

[0011] As a preferred embodiment of the present invention, in step (1), the natural astaxanthin ester is derived from Haematococcus pluvialis, and the mass ratio of the natural astaxanthin ester to the oil phase is (0.1~5):1. The oil phase includes one or more of peanut oil, soybean oil, flaxseed oil, olive oil, corn oil, sunflower seed oil, sesame oil, rapeseed oil, rice bran oil, fish oil and algal oil.

[0012] As a preferred embodiment of the present invention, in step (1), a fat-soluble antioxidant is also added to the oil phase, with an addition amount of 0.01 to 0.2 wt%; the fat-soluble antioxidant includes one or more of vitamin E, propyl gallate, BHA, BHT, and ascorbyl palmitate.

[0013] As a preferred embodiment of the present invention, in step (2), the concentration of the rigid nanoparticle solution is 0.1~5wt%, the astaxanthin ester oil accounts for 10~75% of the mass of the astaxanthin ester emulsion, and the shearing speed is 15000~25000 rpm and the time is 1~3 min.

[0014] As a preferred embodiment of the present invention, in step (3), the wall material includes one or more of maltodextrin, cyclodextrin, gum arabic, CMC, whey protein, soy protein, sodium caseinate, modified starch, fucoidan, sucrose, glucose and lactose; the concentration of the wall material solution is 10~50wt%; and the mass ratio of the astaxanthin ester emulsion to the wall material solution is (0.1~1):1.

[0015] As a preferred embodiment of the present invention, in step (3), one or more water-soluble antioxidants are added to the wall material solution, with an addition amount of 0.01 to 0.2 wt%. The water-soluble antioxidants include one or more of tea polyphenols, vitamin C, anthocyanins, gallic acid, catechins, ethylenediaminetetraacetic acid and their salts.

[0016] The present invention also provides an anti-gastric acid astaxanthin ester microcapsule prepared according to the preparation method described above.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The astaxanthin ester microcapsules prepared by the present invention have gastric acid resistance stability, which reduces the degradation of astaxanthin ester during digestion and absorption, allowing more astaxanthin ester to reach the small intestine stage for absorption and enter the body, thereby improving the utilization efficiency of astaxanthin.

[0018] (2) This invention provides a method for preparing astaxanthin ester microcapsules based on the stability of rigid nanoparticles. The preparation process is simple, does not use small molecule surfactants, is green and safe, and can be efficiently applied in the field of functional foods. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 The contact angle test results are for the CS-OS rigid nanoparticles prepared in step (1) of Example 1; Figure 2 Microscopic morphology diagram of the gastric acid-resistant astaxanthin ester microcapsule powder prepared in Example 1; Figure 3 The images show the microscopic morphological changes of the gastric acid-resistant astaxanthin ester microcapsules prepared in Example 1 during the in vitro digestion and absorption characteristics determination, where (a) to (c) are microscopic morphological images of the initial emulsion, the simulated gastric digestion stage, and the simulated intestinal digestion stage, respectively. Figure 4 The images show the microscopic morphological changes of the astaxanthin ester microcapsules prepared for comparative example 2 during in vitro digestion and absorption characteristics determination, where (a) to (c) are microscopic morphological images of the initial emulsion, the simulated gastric digestion stage, and the simulated intestinal digestion stage, respectively. Detailed Implementation

[0021] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0022] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0023] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0024] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0025] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0026] The raw materials used in the following examples are all commercially available conventional raw materials and are not particularly limited. Room temperature refers to 25-35°C, and will not be described again below.

[0027] The detection method used in this invention is described as follows: (1) Contact angle measurement The wettability of rigid nanoparticles was determined using an optical contact angle meter. A dispersion of CS-OS nanoparticles was placed on a glass slide. The dried sample was placed on the instrument platform, and then 3 μL of ultrapure water was added to the surface. The profile data of the formed droplets were fitted to the Laplace-Young equation, and the instrument software automatically calculated the contact angle value.

[0028] (2) Microscopic morphology determination The microstructure of CS-OS nanoparticles and astaxanthin ester microcapsules was determined using an H-7650 scanning electron microscope. Fluorescence microscopy was used to observe the changes in emulsion size and microstructure during the in vitro digestion of astaxanthin ester microcapsules.

[0029] The following description will not be repeated.

[0030] Example 1 The preparation steps of gastric acid-resistant astaxanthin ester microcapsules are as follows: (1) Dissolve 2 g of CS in 100 mL of 1 wt% acetic acid aqueous solution and stir magnetically overnight. Disperse OS in distilled water at a ratio of 2 wt% and gelatinize at 95 °C for 20 min, then cool naturally to room temperature. Mix the gelatinized OS solution and CS solution at a volume ratio of 1:1, then add 50 mL of 100 mM sodium chloride solution, and finally adjust the pH of the system to 4.0. Mix on a magnetic stirrer for 40 min. Freeze-dry the solution to obtain CS-OS rigid nanoparticles.

[0031] A small amount of CS-OS rigid nanoparticles were taken and their contact angle was measured. The results are as follows: Figure 1 As shown, the contact angle is 88.2±0.3°, which is less than 90°, indicating that the particles are more inclined to form oil-in-water emulsions. The contact angle is close to 90°, indicating that CS-OS rigid nanoparticles have good emulsion stability.

[0032] Add 10 g of natural astaxanthin ester from Haematococcus pluvialis to 20 g of soybean oil, then add 0.01 g of vitamin E and 0.01 g of propyl gallate, stir and mix well to obtain astaxanthin ester oil.

[0033] (2) Dissolve 2 g of CS-OS rigid nanoparticles in 100 mL of ultrapure water until fully dissolved, add 100 g of astaxanthin ester oil, and shear at 15000 rpm for 2 min to obtain astaxanthin ester emulsion with rigid nanoparticle stability.

[0034] (3) 20 g of the above astaxanthin ester emulsion was slowly mixed with 100 g of wall material solution (containing 15 g of maltodextrin, 15 g of whey protein and 10 g of glucose, with the remainder being water), and 0.02 g of tea polyphenols was added. The mixture was then spray-dried under continuous stirring to obtain gastric acid-resistant astaxanthin ester microcapsule powder.

[0035] A small amount of the gastric acid-resistant astaxanthin ester microcapsule powder prepared in this embodiment was weighed and its microstructure was observed using a scanning electron microscope, such as... Figure 2 As shown, the astaxanthin ester microcapsule powder stabilized by rigid nanoparticles is intact and dense, with no obvious cracks or breakage, indicating that the microcapsule powder has good physicochemical stability potential.

[0036] Example 2 The preparation steps of gastric acid-resistant astaxanthin ester microcapsules are as follows: (1) Dissolve 2 g of CS in 200 mL of 1 wt% acetic acid aqueous solution and stir magnetically overnight. Disperse OS in distilled water at a ratio of 2 wt% and gelatinize at 95 °C for 40 min, then cool naturally to room temperature. Mix the gelatinized OS solution and CS solution at a volume ratio of 2:1, then add 20 mL of 100 mM sodium chloride solution, and finally adjust the pH of the system to 4.0. Mix on a magnetic stirrer for 40 min. Freeze-dry the solution to obtain CS-OS rigid nanoparticles.

[0037] Add 2 g of natural astaxanthin ester from Haematococcus pluvialis to 20 g of peanut oil, then add 0.015 g of vitamin E and 0.01 g of propyl gallate, stir and mix well to obtain astaxanthin ester oil.

[0038] (2) Dissolve 2 g of CS-OS rigid nanoparticles in 100 mL of ultrapure water until fully dissolved, add 50 g of astaxanthin ester oil, and shear at 18000 rpm for 2 min to obtain astaxanthin ester emulsion with rigid nanoparticle stability.

[0039] (3) The above 50 g astaxanthin ester emulsion was slowly mixed with 100 g wall material solution (containing 10 g gum arabic, 20 g soybean protein and 5 g sucrose, the remainder being water), and 0.02 g tea polyphenols were added. The mixture was then spray-dried under continuous stirring to obtain gastric acid-resistant astaxanthin ester microcapsule powder.

[0040] Example 3 The preparation steps of gastric acid-resistant astaxanthin ester microcapsules are as follows: (1) Dissolve 4 g of CS in 150 mL of 1 wt% acetic acid aqueous solution and stir magnetically overnight. Disperse OS in distilled water at a ratio of 2 wt% and gelatinize at 95 °C for 30 min, then cool naturally to room temperature. Mix the gelatinized OS solution and CS solution at a volume ratio of 1:2, then add 100 mL of 200 mM sodium chloride solution, and finally adjust the pH of the system to 4.0. Mix on a magnetic stirrer for 40 min. Freeze-dry the solution to obtain CS-OS rigid nanoparticles.

[0041] Add 5 g of natural astaxanthin ester from Haematococcus pluvialis to 80 g of corn oil, then add 0.02 g of vitamin E and 0.01 g of propyl gallate, stir and mix well to obtain astaxanthin ester oil.

[0042] (2) Dissolve 2 g of CS-OS rigid nanoparticles in 200 mL of ultrapure water until fully dissolved, add 100 g of astaxanthin ester oil, and shear at 20000 rpm for 1.5 min to obtain astaxanthin ester emulsion with rigid nanoparticle stability.

[0043] (3) The above 40 g astaxanthin ester emulsion was slowly mixed with 150 g wall material solution (containing 15 g CMC, 15 g sodium caseinate and 20 g glucose, the remainder being water), and 0.015 g tea polyphenols were added. The mixture was then spray-dried under continuous stirring to obtain gastric acid-resistant astaxanthin ester microcapsule powder.

[0044] Example 4 The preparation steps of gastric acid-resistant astaxanthin ester microcapsules are as follows: (1) Dissolve 3 g of CS in 100 mL of 1 wt% acetic acid aqueous solution and stir magnetically overnight. Disperse OS in distilled water at a ratio of 1 wt% and gelatinize at 95 °C for 40 min, then cool naturally to room temperature. Mix the gelatinized OS solution and CS solution at a volume ratio of 1:3, then add 300 mL of 300 mM sodium chloride solution, and finally adjust the pH of the system to 5.0. Mix on a magnetic stirrer for 30 min. Freeze-dry the solution to obtain CS-OS rigid nanoparticles.

[0045] Add 5 g of natural astaxanthin ester from Haematococcus pluvialis to 60 g of soybean oil, then add 0.01 g of vitamin E and 0.02 g of propyl gallate, stir and mix well to obtain astaxanthin ester oil.

[0046] (2) Dissolve 2 g of CS-OS rigid nanoparticles in 200 mL of ultrapure water until fully dissolved, add 100 g of astaxanthin ester oil, and shear at 25000 rpm for 2 min to obtain astaxanthin ester emulsion with rigid nanoparticle stability.

[0047] (3) The above 100 g astaxanthin ester emulsion and 100 g wall material solution (containing 20 g cyclodextrin, 10 g fucoidan, and the remainder water) were slowly mixed, and 0.02 g tea polyphenols were added. The mixture was spray-dried under continuous stirring to obtain gastric acid resistant astaxanthin ester microcapsule powder.

[0048] Example 5 The preparation steps of gastric acid-resistant astaxanthin ester microcapsules are as follows: (1) Dissolve 4 g of CS in 150 mL of 1 wt% acetic acid aqueous solution and stir magnetically overnight. Disperse OS in distilled water at a ratio of 1 wt% and gelatinize at 95 °C for 40 min, then allow to cool naturally to room temperature. Mix the gelatinized OS solution and CS solution at a volume ratio of 3:1, then add 20 mL of 150 mM sodium chloride solution, adjust the pH of the system to 4.0, and mix on a magnetic stirrer for 30 min. Freeze-dry the solution to obtain CS-OS rigid nanoparticles.

[0049] Add 10 g of natural astaxanthin ester from Haematococcus pluvialis to 60 g of olive oil, then add 0.01 g of vitamin E and 0.01 g of propyl gallate, stir and mix well to obtain astaxanthin ester oil.

[0050] (2) Dissolve 2 g of CS-OS rigid nanoparticles in 200 mL of ultrapure water until fully dissolved, add 100 g of astaxanthin ester oil, and shear at 25000 rpm for 2 min to obtain astaxanthin ester emulsion with rigid nanoparticle stability.

[0051] (3) The above 50 g astaxanthin ester emulsion was slowly mixed with 100 g wall material solution (containing 5 g maltodextrin, 20 g sodium caseinate and 5 g glucose, the remainder being water), and 0.02 g tea polyphenols were added. The mixture was then spray-dried under continuous stirring to obtain gastric acid-resistant astaxanthin ester microcapsule powder.

[0052] Comparative Example 1 Similar to Example 1, except that chitosan is not added in step (1). However, since a single OS solution is difficult to form rigid nanoparticles, an astaxanthin ester emulsion with a rigid interface stability cannot be formed, and the oil and water quickly separate, making it impossible to continue preparing subsequent products.

[0053] Comparative Example 2 Same as Example 1, except that sodium chloride solution is not added in step (1).

[0054] Effect verification: In vitro digestion and absorption characteristics of astaxanthin ester microcapsules resistant to gastric acid: Initial emulsion: 0.1 g of the microcapsule sample prepared in Example 1 was dissolved in ultrapure water, and its particle size potential and microstructure during the observation period were measured, such as... Figure 3 As shown in Figure (a).

[0055] Simulated gastric digestion stage: 10 mL of simulated gastric juice was added, mixed, and the pH was adjusted to 1.5. The mixture was continuously shaken at 120 rpm and 37℃ for 2 h to simulate gastric digestion. The particle size potential and microstructure during the observation period were measured, such as... Figure 3 As shown in Figure (b).

[0056] Simulated intestinal digestion stage: After simulated gastric digestion, the pH of the system was adjusted to 7.0 with NaOH solution (0.1 M); 20 mL of simulated intestinal fluid (SIF, pH = 7.0) was added (simulated intestinal fluid: 30 mM CaCl2, 39 mM K2HCO3, 150 mM NaCl, 8 mg / mL bile extract and 30 mg / mL porcine pancreatic lipase, adjusted to pH 7.0). Then, the above mixture was continuously shaken at 120 rpm and 37℃ for 2 h to simulate intestinal digestion. The particle size potential and microstructure during the observation period were measured, such as... Figure 3 As shown in Figure (c).

[0057] Depend on Figure 3 It can be seen that in the initial stage, the astaxanthin ester microcapsule powder reconstituted emulsion prepared in Example 1 showed uniformly dispersed, spherical oil droplets, indicating that the emulsion was stable. During the simulated gastric digestion stage, the oil droplets partially aggregated due to the influence of gastric acid. However, the rigid interface layer formed by the CS-OS nanoparticles exhibited good stability, preventing further fusion of the oil droplets and enhancing the emulsion's resistance to gastric acid, thus avoiding the excessive release and degradation of astaxanthin esters during gastric digestion. In the model intestinal digestion stage, a large number of oil droplets aggregated and fused into a large oil droplet emulsion, indicating that the emulsion had entered the fusion and release stage, controlling the release and absorption of astaxanthin esters in the intestine.

[0058] In vitro digestion and absorption experiments showed that the CS-OS nanoparticle-stabilized astaxanthin ester microcapsules prepared in Example 1 have gastric acid resistance, reduce the release and degradation of astaxanthin esters during gastric digestion, and can deliver more astaxanthin esters to the intestinal tract, thereby improving the bioavailability of astaxanthin esters.

[0059] The gastric acid-resistant astaxanthin ester microcapsules prepared in Examples 2-5 were subjected to in vitro model digestion and absorption experiments according to the above method. The results showed that they also have gastric acid-resistant stability, reduce the release and degradation of astaxanthin ester during gastric digestion, and can deliver more astaxanthin ester to the intestinal stage, thereby improving the bioavailability of astaxanthin ester.

[0060] The gastric acid-resistant astaxanthin ester microcapsules prepared in Comparative Example 2 were subjected to in vitro model digestion and absorption experiments according to the above method. The microscopic morphology images of the initial emulsion, the simulated gastric digestion stage, and the simulated intestinal digestion stage are shown in the figures below. Figure 4 As shown in (a) to (c), by Figure 4As can be seen, during the simulated gastric digestion stage, although the emulsion droplets remained spherical, their size was significantly larger than the initial emulsion droplet size. This result indicates that gastric acid disrupted the initial emulsion interface structure to some extent, leading to the aggregation of small droplets into larger ones. Therefore, the sample exhibited poor resistance to gastric acid. Ultimately, this resulted in a large aggregation of droplets during the model's intestinal digestion stage, reducing the contact area between the astaxanthin ester and lipase, thus decreasing the release and utilization rate of astaxanthin. This was due to the lack of sodium chloride, making it difficult to adjust the ionic strength of the solution, affecting the formation of rigid nanoparticles, leading to reduced stability of the astaxanthin ester emulsion, and ultimately resulting in astaxanthin ester microcapsules with poor resistance to gastric acid.

[0061] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing gastric acid-resistant astaxanthin ester microcapsules, characterized in that, Includes the following steps: (1) Preparation of rigid nanoparticles: Chitosan was dissolved in an acidic solution to obtain a chitosan solution; octenyl succinate starch ester was dispersed in water to obtain an octenyl succinate starch ester solution, which was gelatinized and cooled, then mixed with the chitosan solution, and then sodium chloride solution was added. After freeze-drying, rigid nanoparticles were obtained. Preparation of astaxanthin ester oil: Natural astaxanthin esters are dissolved in the oil phase to obtain astaxanthin ester oil; (2) Preparation of rigid nanoparticle stabilized astaxanthin ester emulsion: The rigid nanoparticles obtained in step (1) are dissolved in water to obtain a rigid nanoparticle solution, the astaxanthin ester oil is added, and the astaxanthin ester emulsion is obtained after shearing. (3) The astaxanthin ester emulsion obtained in step (2) is mixed with the wall material solution and spray-dried to obtain the gastric acid resistant astaxanthin ester microcapsules.

2. The preparation method according to claim 1, characterized in that, In step (1), the acidic solution includes an aqueous solution of acetic acid with a concentration of 0.8 to 1.5 wt%, the chitosan solution has a concentration of 10 to 30 g / L, and the octenyl succinic acid starch ester solution has a concentration of 0.1 to 10.0 wt%.

3. The preparation method according to claim 1, characterized in that, In step (1), the gelatinization temperature is 85~95℃ and the time is 20~40 min; the volume ratio of the gelatinized octenyl succinic acid starch ester solution to the chitosan solution is (0.2~5):1; the concentration of the sodium chloride solution is 0.1~600 mM and the volume ratio of the sodium chloride solution to the chitosan solution is (0.05~1):1; the sodium chloride solution is added to adjust the pH of the system to 2~9 and the mixture is stirred for 30~40 min.

4. The preparation method according to claim 1, characterized in that, In step (1), the natural astaxanthin ester is derived from Haematococcus pluvialis, and the mass ratio of the natural astaxanthin ester to the oil phase is (0.1~5):

1. The oil phase includes one or more of peanut oil, soybean oil, flaxseed oil, olive oil, corn oil, sunflower seed oil, sesame oil, rapeseed oil, rice bran oil, fish oil, and algal oil.

5. The preparation method according to claim 4, characterized in that, In step (1), a fat-soluble antioxidant is also added to the oil phase, with an addition amount of 0.01 to 0.2 wt%; the fat-soluble antioxidant includes one or more of vitamin E, propyl gallate, BHA, BHT, and ascorbyl palmitate.

6. The preparation method according to claim 1, characterized in that, In step (2), the concentration of the rigid nanoparticle solution is 0.1~5wt%, the astaxanthin ester oil accounts for 10~75% of the mass of the astaxanthin ester emulsion, the shearing speed is 15000~25000 rpm, and the time is 1~3 min.

7. The preparation method according to claim 1, characterized in that, In step (3), the wall material includes one or more of maltodextrin, cyclodextrin, gum arabic, CMC, whey protein, soy protein, sodium caseinate, modified starch, fucoidan, sucrose, glucose and lactose; the concentration of the wall material solution is 10~50wt%; the mass ratio of the astaxanthin ester emulsion to the wall material solution is (0.1~1):

1.

8. The preparation method according to claim 1, characterized in that, In step (3), one or more water-soluble antioxidants are added to the wall material solution, with an addition amount of 0.01 to 0.2 wt%. The water-soluble antioxidants include one or more of tea polyphenols, vitamin C, anthocyanins, gallic acid, catechins, ethylenediaminetetraacetic acid and their salts.

9. An anti-gastric acid astaxanthin ester microcapsule prepared by the preparation method according to any one of claims 1 to 8.

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