A porous microspheric product of resistant starch 3

Abstract

The application discloses RS3 resistant starch porous microsphere products and belongs to the technical field of starch-based functional materials. The RS3 resistant starch porous microsphere takes high-crystallinity RS3 type resistant starch as a skeleton base material and simultaneously satisfies the following conditions: the DSC peak melting point is greater than or equal to 120 DEG C; the mass loss rate is less than 5% after incubation in a simulated small intestinal digestive juice for 2 hours; no characteristic peak of a chemical crosslinking agent is detected in infrared spectroscopy; a plurality of micron-level cavities are internally provided; the average particle size is 1-2000 mu m; the specific surface area is 5-200 m2 / g; the average pore size of the internal cavity is 0.1-100 mu m; and the swelling rate is less than or equal to 5% after pressure-free soaking in deionized water at 25 DEG C for 24 hours. The application directly locks the protection range through the physical characteristics of the product itself, and no matter what preparation method is adopted, as long as the product characteristics fall within the above range, infringement is constituted. Relying on the RS3 dense microcrystalline structure, the product still maintains the complete porous structure and stable function in an aqueous phase and a high-temperature environment, has the three advantages of clean label, water resistance and high-temperature resistance, and forms a trinity protection closed loop of'method-product-detection' with the preparation method patent and the detection method patent.

Description

Technical Field

[0001] This invention belongs to the field of starch-based functional materials technology, specifically relating to a porous microsphere product with highly crystalline RS3 type resistant starch as the skeleton substrate. Background Technology

[0002] RS3 resistant starch is a functional starch material manufactured through a purely physical annealing and regeneration process. Unlike natural starch and chemically modified starch, highly crystalline RS3 resistant starch possesses a dense and ordered double-helix microcrystalline structure, a melting point ≥120℃, is not hydrolyzed by digestive enzymes in the small intestine, is heat-resistant, and does not absorb water or swell in water. Porous microspheres made with highly crystalline RS3 resistant starch as the backbone substrate, due to their abundant micron-sized cavities and large specific surface area, can be used as encapsulation carriers, adsorbent materials, sustained-release carriers, and lightweight fillers for active substances, and have been widely applied in various fields such as food, cosmetics, pharmaceuticals, industry, and environmental protection.

[0003] However, current patent protection primarily focuses on the preparation methods and application scenarios. Regarding the protection of the RS3 resistant starch porous microspheres themselves, existing method patents limit product claims to "products obtained by this method." Such claims face evidential difficulties in infringement determinations—the patent holder needs to prove that the accused infringing product was manufactured using the patented method, which is virtually impossible to deduce from the finished product through reverse engineering. If competitors use different process routes to manufacture RS3 porous microspheres with the same structural features, they may circumvent the method patent protection.

[0004] Therefore, there is an urgent need in this field for an independent product patent—one that is not tied to any specific manufacturing method, but rather defines the scope of protection solely through the physicochemical characteristics of the product itself. As long as the structural features of the allegedly infringing product fall within the scope of the claims, infringement is constituted regardless of the manufacturing method used. This product patent, in conjunction with a method patent, forms a three-pronged protection loop of "method-product-testing": the method patent protects "how to do it," the product patent protects "what is produced," and the testing patent provides the technical means to "prove infringement." Summary of the Invention

[0005] Purpose of the invention

[0006] The purpose of this invention is to provide an RS3 resistant starch porous microsphere product, which defines the scope of protection by the product's own physicochemical characteristics—including melting temperature, digestibility, chemical crosslinking agent anisotropy, porous structure parameters, and water resistance—without relying on any specific manufacturing method, fundamentally eliminating the possibility for competitors to circumvent patent protection by changing manufacturing processes.

[0007] In this specification, "skeleton substrate" refers to the entire supporting structure of the microspheres being composed of highly crystalline RS3-type resistant starch. This does not exclude the active substances loaded within the internal cavities of the microspheres and the physical coatings applied to the outer surface of the microspheres. The active substances and physical coatings are functional loading components of the microspheres, not skeleton structural components.

[0008] Technical solution

[0009] The RS3 resistant starch porous microspheres provided by this invention use highly crystalline RS3 resistant starch as the backbone substrate. The RS3 resistant starch porous microspheres of this invention simultaneously satisfy the following eight characteristics:

[0010] (a) Peak melting point determined by DSC method ≥120℃. High-crystallinity RS3 resistant starch, after pure physical annealing and reversion, forms a dense and ordered double-helix microcrystalline structure with high microcrystalline regularity and a melting temperature far higher than that of natural starch (60-80℃). This characteristic is the core thermodynamic indicator that distinguishes this product from natural starch microspheres and ordinary reverted starch microspheres.

[0011] (b) After incubation in simulated small intestinal digestive fluid (containing α-amylase, pH 6.8, 37°C) for 2 hours, the mass loss rate was less than 5%. The dense microcrystalline structure of highly crystalline RS3 resistant starch forms a natural physical barrier for α-amylase, preventing enzyme molecules from penetrating the crystal lattice to contact the starch molecular chains. This characteristic is the core biochemical indicator that distinguishes this product from natural starch microspheres and digestible starch microspheres.

[0012] (c) No characteristic peaks of chemical cross-linking agents were detected in the infrared spectrum. This product is manufactured using purely physical methods without the addition of any chemical cross-linking agents. Starch microspheres prepared using chemical cross-linking methods (such as sodium trimetaphosphate, epichlorohydrin, or glutaraldehyde cross-linking) will exhibit corresponding characteristic absorption peaks of the cross-linking agent in their infrared spectra. This characteristic is the core spectroscopic indicator that distinguishes this product from chemically cross-linked starch microspheres.

[0013] (d) The interior contains multiple micron-sized cavities. The abundant cavity structure inside the microspheres provides a spatial basis for the loading, adsorption, and sustained release of active substances.

[0014] (e) Average particle size is 1 μm-2000 μm. The particle size range covers all needs from ultrafine powders for cosmetics to large particle carriers for industrial applications.

[0015] (f) Specific surface area is 5-200 m² / g. The high specific surface area comes from the rich micron- and nano-scale pore structure inside the microspheres.

[0016] (g) The average pore size of the internal cavity is 0.1 μm-100 μm. The pore size distribution covers the entire scale from nanoscale sustained-release channels to micrometer-scale loading spaces.

[0017] (h) After soaking in deionized water at 25℃±1℃ without pressure for 24 hours, the swelling rate is ≤5%. The dense microcrystalline structure of the highly crystalline RS3 resistant starch prevents the microspheres from absorbing water and swelling in water, thus maintaining the integrity of the particle shape.

[0018] The above eight characteristics comprehensively define the RS3 resistant starch porous microspheres of the present invention from five dimensions: thermodynamics, biochemistry, spectroscopy, structural parameters, and physical properties. These characteristics are independent of any specific manufacturing method—regardless of the manufacturing method, as long as all eight characteristics of the product fall within the defined range, it constitutes the RS3 resistant starch porous microsphere product of the present invention.

[0019] The RS3 resistant starch porous microspheres of this invention possess a unique synergistic effect of "highly crystalline water-resistant substrate + porous structure". Ordinary starch porous microspheres rapidly absorb water, swell, and disintegrate in humid and aqueous environments, with the porous structure completely collapsing and failing within hours, allowing only short-term use in dry environments. While chemically cross-linked starch porous microspheres offer some water resistance, they leave chemical residues, and characteristic peaks of the cross-linking agent can be detected by infrared spectroscopy; furthermore, they cannot withstand high-temperature sterilization above 120°C. The RS3 resistant starch porous microspheres of this invention simultaneously achieve structural and functional stability: relying on the dense microcrystalline structure of RS3, they maintain the integrity of the porous structure in aqueous environments, with a swelling rate ≤5%, and highly stable adsorption performance and sustained-release behavior; they can withstand high-temperature sterilization at 121°C; they contain no chemical cross-linking agents, and no characteristic peaks of the cross-linking agent can be detected by infrared spectroscopy, meeting clean label requirements. This simultaneous possession of the triple advantages of "water resistance + high-temperature resistance + no chemical residue" is unattainable with existing starch porous microspheres and represents an unexpected technical effect.

[0020] All eight characteristics mentioned above can be objectively verified using publicly available and standardized testing methods. These testing methods are all protected by the applicant's prior patents. The product patent and the testing patent form a complete closed loop of technical protection—the product characteristics are clearly defined in the claims, and the testing methods are clearly disclosed in the specification. When exercising their rights, the patent holder can directly use the matching testing methods to identify commercially available products, making the evidence simple and the conclusions objective.

[0021] Beneficial effects

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) It is not bound to any manufacturing method and has a wide scope of protection. As long as the product structural features fall within the scope of the claims, it constitutes infringement. Regardless of the preparation process used, it fundamentally eliminates the possibility of bypassing patent protection by changing the manufacturing process. (2) Product features can be objectively detected and infringement evidence is simple. All eight limiting features can be verified by publicly standardized testing methods. When the rights holder defends his rights, he does not need to prove what manufacturing process the accused infringing product used. He only needs to test the product itself to complete the infringement evidence. (3) It forms a three-in-one protection closed loop of "method-product-testing" with the preparation method patent and the testing method patent. The preparation method patent protects "how to do it", the product patent protects "what is produced", and the testing patent provides the technical means of "how to prove infringement". The three are used together to build a three-dimensional patent defense system. (4) Relying on the synergistic gain of "high crystallinity water-resistant substrate + porous structure", it has the triple advantages of water resistance, high temperature resistance and no chemical residue. Ordinary starch porous microspheres collapse upon contact with water, and chemically cross-linked porous microspheres leave residues and are not heat-resistant. The RS3 resistant starch porous microspheres of this invention are the only porous starch microsphere products that can simultaneously meet these three performance indicators. (5) The eight characteristics comprehensively define the product from five dimensions: thermodynamics, biochemistry, spectroscopy, structural parameters, and physical properties. Similarity of a single characteristic may be a coincidence, but the only reasonable source of similarity among all eight characteristics is the use of the RS3 resistant starch porous microsphere product of this invention. Detailed Implementation

[0023] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto.

[0024] Preparation Example—Preparation of RS3 Porous Microspheres by Spray Drying Combined with Annealing: High-crystallinity RS3 resistant starch (DSC peak melting point 124℃, XRD crystallinity 45%) was prepared by adding deionized water to form a 15% (w / w) starch slurry. After homogenization for 30 minutes, it was spray-dried. Spray drying parameters: inlet air temperature 120℃, outlet air temperature 70℃, feed rate 15mL / min. The microsphere precursor obtained by spray drying was annealed at 55℃ and 85% relative humidity for 12 hours, and then dried at 50℃ until the moisture content was below 12%, yielding RS3 resistant starch porous microspheres. This preparation method is only used to demonstrate the feasibility of preparing RS3 resistant starch porous microspheres and does not constitute any limitation on the scope of the claims.

[0025] Example 1 – RS3 Resistant Starch Porous Microspheres Meeting All Characteristic Requirements The RS3 resistant starch porous microsphere sample prepared in the above preparation example was used. DSC analysis showed a peak melting point of 124.5℃, meeting characteristic (a) ≥120℃. Incubation in simulated small intestinal digestive fluid (containing α-amylase, pH 6.8, 37℃) for 2 hours resulted in a mass loss rate of 3.2%, meeting characteristic (b) less than 5%. Infrared spectroscopy showed no characteristic absorption peaks of common chemical cross-linking agents such as sodium trimetaphosphate and epichlorohydrin in the characteristic wavenumber region, meeting characteristic (c). Scanning electron microscopy revealed multiple micron-sized cavities within the microspheres, meeting characteristic (d). Laser particle size analysis showed an average particle size of 45μm, meeting characteristic (e) within the 1-2000μm range. Nitrogen adsorption-desorption analysis showed a specific surface area of ​​32.5 m² / g, meeting characteristic (f) within the 5-200 m² / g range. The average pore size of the internal cavity is 8.5 μm, which meets the 0.1-100 μm range of characteristic (g). After soaking in deionized water at 25℃±1℃ without pressure for 24 hours, the swelling rate is 3.2%, which meets the characteristic (h) ≤5%. SEM random observation of 120 particles showed that 97.5% of the particles had intact structures. The above test results prove that the sample meets all eight characteristic requirements of this invention.

[0026] Example 2 – Comparison with Ordinary Corn Starch Microspheres: Commercially available ordinary corn starch microspheres were tested for eight characteristics according to the method in Example 1. The results showed that: the DSC peak melting point was only 75.3℃, failing to meet characteristic (a); the mass loss rate after 2 hours of simulated small intestinal digestion was 68.5%, failing to meet characteristic (b); no characteristic peak of the chemical cross-linking agent was detected in the infrared spectrum, meeting characteristic (c); it has a porous structure, meeting characteristic (d); and the swelling rate was as high as 185%, failing to meet characteristic (h). Only four of the eight characteristics were met, thus not falling within the scope of protection of this invention. Although ordinary starch porous microspheres have a porous structure, their amorphous starch substrate rapidly absorbs water and swells in water, and the porous structure completely collapses within 2 hours, making it unable to maintain adsorption and sustained-release functions in an aqueous environment.

[0027] Example 3 – Comparison of Chemically Cross-linked Starch Microspheres: Commercially available sodium trimetaphosphate cross-linked starch microspheres were tested for eight characteristics according to the method in Example 1. The results showed: the DSC peak melting point was 110.2℃, failing to meet characteristic (a); the mass loss rate after 2 hours of simulated small intestinal digestion was 8.5%, failing to meet characteristic (b); the infrared spectrum detected the characteristic absorption peaks of the sodium trimetaphosphate cross-linking agent P=O and POC at a specific wavenumber, failing to meet characteristic (c); the swelling rate was 12.8%, failing to meet characteristic (h). Only four of the eight characteristics were met, thus not falling within the scope of protection of this invention. Although chemically cross-linked starch microspheres have certain water resistance and digestibility, their infrared spectra inevitably contain characteristic peaks of the cross-linking agent, failing to meet clean label requirements and unable to withstand high-temperature sterilization at 121℃. This example demonstrates that characteristic (c) is the decisive identification indicator distinguishing this product from chemically cross-linked starch microspheres.

[0028] Example 4 – Comparison with Ordinary Retrograded RS3 Porous Microspheres: Ordinary retrograded RS3 (crystallinity approximately 25%, DSC peak melting point approximately 85℃) was used to prepare porous microspheres using the same process as in Example 1. The eight characteristics were tested according to the method in Example 1. The results showed: the DSC peak melting point was 85.5℃, not meeting characteristic (a); the mass loss rate after 2 hours of simulated small intestinal digestion was 15.8%, not meeting characteristic (b); no characteristic peak of the chemical cross-linking agent was detected in the infrared spectrum, meeting characteristic (c); the swelling rate was 22.5%, not meeting characteristic (h); SEM observation showed that only 35% of the particles had intact structures, not meeting the integrity rate requirement corresponding to the characteristic. Only four of the eight characteristics were met, thus not falling within the scope of protection of this invention. This example demonstrates that not any RS3 can simultaneously meet all eight characteristics when made into porous microspheres. Only high-crystallinity RS3 with a crystallinity ≥40% and a DSC peak melting point ≥120℃ can achieve full characteristic compliance, further confirming the non-obviousness of this product.

[0029] Example 5 – Verification of Microspheres Prepared by Different Methods Falling Within the Scope of Protection High-crystallinity RS3 porous microspheres prepared by ultra-high pressure assisted annealing (treated under ultra-high pressure of 300 MPa / 25℃ for 20 minutes followed by annealing at 55℃ for 12 hours) and high-crystallinity RS3 porous microspheres prepared by extrusion expansion coupled with reversion (treated under extrusion expansion at 110℃ / 250 rpm followed by reversion at 55℃ for 16 hours) were subjected to eight characteristic tests according to the method in Example 1. The results showed that the DSC peak melting points of the two microspheres were 122.8℃ and 123.5℃, respectively, both satisfying characteristic (a); the mass loss rates after 2 hours of simulated small intestinal digestion were 3.5% and 3.8%, respectively, both satisfying characteristic (b); no characteristic peaks of chemical cross-linking agents were detected in the infrared spectra of either microsphere, satisfying characteristic (c); both microspheres possessed porous structures, satisfying characteristic (d); and the swelling rates were 3.4% and 3.6%, respectively, both satisfying characteristic (h). All eight characteristics of the two microspheres fell within the scope of protection of this invention. This example demonstrates that regardless of the preparation process used, as long as the physical structural characteristics of the product meet the eight requirements, it constitutes the RS3 resistant starch porous microsphere product of this invention, achieving broad-spectrum protection that "does not concern itself with the process, but only with the product".

Claims

1. An RS3-resistant starch porous microsphere, characterized in that, The RS3 resistant starch porous microspheres use highly crystalline RS3 resistant starch as the backbone substrate and simultaneously meet the following characteristics: (a) peak melting point determined by DSC method ≥120℃; (b) mass loss rate less than 5% after incubation in simulated small intestinal digestive fluid (containing α-amylase, pH 6.8, 37℃) for 2 hours; (c) no characteristic peaks of chemical cross-linking agents detected by infrared spectroscopy; (d) multiple micron-sized cavities inside; (e) average particle size of 1μm-2000μm; (f) specific surface area of ​​5-200m² / g; (g) average pore size of internal cavities of 0.1μm-100μm; (h) swelling rate ≤5% after immersion in deionized water at 25℃±1℃ without pressure for 24 hours.

2. The RS3 resistant starch porous microspheres according to claim 1, characterized in that, The skeleton substrate refers to the microsphere's support structure, which is entirely composed of highly crystalline RS3-type resistant starch. This does not exclude the active substances loaded within the micron-sized cavities and the physical coatings applied to the outer surface of the microspheres.

3. The RS3 resistant starch porous microspheres according to claim 1, characterized in that, The outer surface of the RS3 resistant starch porous microspheres has micron-sized channels and depressions, and the micron-sized channels are connected to or independently distributed with the internal cavity.

4. The RS3 resistant starch porous microspheres according to claim 1, characterized in that, The RS3 resistant starch porous microspheres, after being incubated in simulated gastric fluid at pH 1.2 at 37°C for 4 hours, exhibited a solid mass retention rate of ≥90%.

5. The RS3 resistant starch porous microspheres according to claim 1, characterized in that, The RS3 resistant starch porous microspheres contain active substances within their internal cavities. These active substances are selected from at least one of the following: oils, probiotics, vitamins, fragrances, active pharmaceutical ingredients, active cosmetic ingredients, repair agents, and nutritional active substances.

6. The RS3 resistant starch porous microspheres according to claim 1, characterized in that, The outer surface of the RS3 resistant starch porous microspheres is provided with a physical sealing layer, which is formed by physical fusion or physical coating and does not involve chemical cross-linking reaction.

7. The RS3 resistant starch porous microspheres according to claim 1, characterized in that, After the RS3 resistant starch porous microspheres were immersed in deionized water at 25℃±1℃ for 24 hours without pressure, no less than 100 particles were randomly observed by scanning electron microscopy. The proportion of particles with intact morphology and no cracks or collapses was no less than 95%.

8. The RS3 resistant starch porous microspheres according to claim 1, characterized in that, The RS3 resistant starch porous microspheres do not absorb water, swell, or disintegrate in water, and maintain their particle shape in a humid environment.

9. The application of RS3 resistant starch porous microspheres according to any one of claims 1 to 8 in the fields of food, cosmetics, medicine, and industrial adsorption.