High-stability chelated iron feed additive, preparation method and feed

Abstract

The present application relates to the technical field of feed additive, and provides a high-stability chelated iron feed additive, which comprises a reducing component A, a high-temperature protection component B and a carrier component C in a mass ratio of 2-4:1-2:5-8; the reducing component A comprises vitamin C; the high-temperature protection component B comprises astragalus polysaccharide and tea polyphenol palmitate; and the carrier component C is modified hydrotalcite; a preparation method thereof comprises the following steps: dispersing the carrier component C in a solvent to prepare a saturated solution, adding part of the reducing component A and the high-temperature protection component B, carrying out inclusion, cooling and crystallization, and then drying and crushing to obtain a powdered molecular inclusion compound; and mixing the inclusion compound with the remaining reducing component A and high-temperature protection component B to prepare the feed additive; and the feed additive can solve the problems in the prior art, such as easy oxidation of ferrous iron, invalidation of antioxidants due to a high-temperature process of spray drying, and easy moisture absorption of the product.

Description

Technical Field

[0001] This invention relates to the field of feed additive technology, and more specifically, to a highly stable chelated iron feed additive, its preparation method, and the feed thereof. Background Technology

[0002] Iron is an essential trace element for animals, and iron deficiency anemia is a widespread nutritional health problem globally. Among various iron supplements, small peptide chelated iron is considered an ideal direction for iron supplement development due to its advantages such as high absorption rate, good bioavailability, and minimal gastrointestinal irritation. However, physiologically active ferrous iron is chemically extremely unstable and is easily oxidized to ferric iron during production and storage, leading to product quality deterioration. This not only reduces iron bioavailability but also produces a rusty odor, severely affecting the product's sensory quality and shelf life.

[0003] Currently, the industrial production of small peptide chelated iron typically employs a process route of "enzymatic hydrolysis-chelation-spray drying." During the chelation reaction stage, the liquid temperature is maintained at 60-70℃, while during the spray drying stage, the inlet air temperature reaches as high as 200-220℃, and the outlet air temperature is approximately 100-120℃. The instantaneous temperature of the liquid during drying can rise to over 60-100℃. This variable temperature condition throughout the entire production process poses a significant challenge to the stabilization of divalent iron.

[0004] In existing technologies, there are two main types of solutions to address the problem of easy oxidation of ferrous iron: one is to perform a coating treatment after the finished product is produced; the other is to add antioxidants in the later stages of the finished product production. However, although these post-treatment methods can play a certain role in color protection and efficacy stabilization, they will add extra production steps and increase production costs. Moreover, small peptide products are extremely hygroscopic, and it is difficult for the added antioxidants to be evenly dispersed in the powder system. They also tend to adhere to the equipment walls, increasing the difficulty of cleaning.

[0005] The patent with publication number CN122250567A discloses a sucrose complex zinc-iron-copper-manganese composite premixed feed additive and its preparation method. Although it mentions adding antioxidants in the chelation reaction stage, it does not take into account the core problem of poor thermal stability and easy failure of antioxidants under the high temperature conditions of spray drying in the subsequent preparation of small peptide products. This makes it impossible to fully exert the antioxidant and iron stabilizing effects, and it is difficult to achieve efficient and low-cost steady-state production of divalent iron. Summary of the Invention

[0006] In view of the problems in the prior art, such as the easy oxidation of ferrous iron, the failure of antioxidants due to the high temperature process of spray drying, and the easy absorption of moisture by the product, the present invention provides a highly stable chelated iron feed additive, a preparation method, and feed.

[0007] The embodiments of the present invention are achieved through the following technical solutions: A highly stable chelated iron feed additive comprises a reducing component A, a high-temperature protective component B, and a carrier component C in a mass ratio of 2~4:1~2:5~8; wherein: The reducing component A includes vitamin C, and also includes at least one of reduced iron powder and reduced glutathione; the mass ratio of vitamin C to reduced iron powder is 2~5:1; the mass ratio of vitamin C to reduced glutathione is 1:0.2~0.5; The high-temperature protection component B includes astragalus polysaccharide and tea polyphenol palmitate, wherein the mass ratio of astragalus polysaccharide to tea polyphenol palmitate is 1~3:1; The carrier component C is modified hydrotalcite, and at least a portion of the reducing component A and / or the high-temperature protective component B are encapsulated in the internal channels and / or surface channels of the carrier component C to form a molecular inclusion complex.

[0008] This invention also provides a method for preparing a highly stable chelated iron feed additive, comprising the following steps: S1. Disperse the carrier component C in a solvent (such as deionized water or ethanol-water mixed solvent) to prepare a saturated or supersaturated solution, add part of the reducing component A and part of the high temperature protection component B, stir and encapsulate at 45~55℃ for 3~5h, cool and crystallize, dry and pulverize to obtain a powdered molecular inclusion complex; S2. The powdered molecular inclusion complex obtained in step S1 is mixed with the remaining reducing component A and high-temperature protective component B to prepare the feed additive.

[0009] This invention also provides a method for preparing a highly stable chelated iron feed, comprising the following steps: A1: Preparation of small peptide solution: Protein raw materials are hydrolyzed, enzyme inactivated, centrifuged and dried to obtain small peptide powder, which is then mixed with water to prepare a small peptide solution with a mass concentration of 30%-40%. A2: Chelation reaction: Under a protective atmosphere (such as nitrogen), add a ferrous salt solution (ferrous sulfate or ferrous chloride, preferably ferrous sulfate) to the small peptide solution obtained in step A1, adjust the pH to 4.5-6.0 with citric acid or sodium hydroxide solution, and stir the reaction at 60-70℃ for 0.5-2.0 h; 0.5-1.0 h after the reaction starts, add the above-mentioned feed additive (the mass of the feed additive accounts for 0.5%-2.0% of the mass of the small peptide powder), the initial addition of the feed additive is 60%-70% of the total amount; A3: High-temperature protection reinforcement: 0.5 hours before the end of step A2 reaction and before entering spray drying, add the remaining feed additives and stir evenly; A4: Spray drying: Spray dry the liquid obtained in step A3 with an inlet air temperature of 200-220℃ and an outlet air temperature of 100-120℃. Collect the dried powder to obtain chelated ferrous feed.

[0010] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects: 1. This invention achieves stable protection of ferrous iron throughout the entire process from liquid-phase chelation reaction to high-temperature spray drying to product storage through the synergistic effect of modified hydrotalcite, reducing component A, and high-temperature protective component B. The small peptide chelated ferrous product prepared by the method of this invention can achieve a ferrous iron retention rate of about 97%, and after 6 months of storage, the ferrous iron residual rate can still reach more than 94%.

[0011] 2. This invention improves the moisture resistance of hydrotalcite by modifying its hydrophobic surface, rather than relying on external desiccant or post-coating process. The hydrophobically modified hydrotalcite can be uniformly dispersed in the product, which reduces the overall affinity of the product for water and acts as a hydrophobic isolation site to break the hydrogen bond network between small peptide molecules, significantly delaying the moisture absorption and agglomeration process of the product in high humidity environment. During the spray drying process, it can migrate and accumulate on the surface of droplets to form a surface film with an interfacial barrier effect.

[0012] 3. This invention utilizes the interlayer confinement protection of modified hydrotalcite, the colloidal network protection of astragalus polysaccharide, and the high-temperature stability of tea polyphenol palmitate to form a protective colloidal network film at high temperatures. This film encapsulates chelated iron molecules and reducing active groups, providing comprehensive high-temperature antioxidant protection at both the gas and liquid phases. This ensures that the reducing components encapsulated in the modified hydrotalcite remain active and continue to be released during the high-temperature impact phase. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0014] The following is a detailed description of a highly stable chelated iron feed additive and its preparation method provided by embodiments of the present invention.

[0015] This invention provides a highly stable chelated iron feed additive, comprising: a reducing component A, a high-temperature protective component B, and a carrier component C, wherein the mass ratio of the reducing component A, the high-temperature protective component B, and the carrier component C is 2~4:1~2:5~8; wherein: The reducing component A includes vitamin C, and also includes at least one of reduced iron powder and reduced glutathione; the mass ratio of vitamin C to reduced iron powder is 2~5:1; the mass ratio of vitamin C to reduced glutathione is 1:0.2~0.5; The high-temperature protection component B is astragalus polysaccharide and tea polyphenol palmitate, and the mass ratio of astragalus polysaccharide to tea polyphenol palmitate is 1~3:1. The carrier component C is modified hydrotalcite, and at least a portion of the reducing component A and / or the high-temperature protective component B are encapsulated in the internal channels and / or surface channels of the carrier component C to form a molecular inclusion complex.

[0016] Vitamin C is a potent reducing agent; its enediol structure can reduce ferric ions to ferrous ions, while simultaneously being oxidized to dehydroascorbic acid. Furthermore, in the aqueous phase, vitamin C rapidly undergoes an electron transfer reaction with ferric ions, instantly reducing them back to ferrous ions. Reduced iron powder, acting as a "zero-valent iron reservoir," continuously releases ferrous ions and consumes dissolved oxygen in the system through micro-electrochemical action, providing long-lasting reducing protection. The thiol group in reduced glutathione possesses strong reducing properties, altering the redox potential of the system. Simultaneously, the thiol group can form coordination complexes with transition metal ions, reducing their catalytic oxidation activity. Therefore, the components in reducing component A synergistically construct a buffer system with multi-level reducing capacity, inhibiting the oxidative deactivation of ferrous iron.

[0017] Astragalus polysaccharide is a heteropolysaccharide extracted from the roots of Astragalus membranaceus or Astragalus mongholicus. Its molecular chain is composed of monosaccharides such as D-glucose, D-galactose, and L-arabinose linked by glycosidic bonds, exhibiting a multi-branched structure. Astragalus polysaccharide has a high glass transition temperature, and at high temperatures, it can form a protective colloidal network film layer, encapsulating chelated iron molecules and reducing active groups, isolating high-temperature oxygen free radicals, and slowing down the thermal migration and thermal degradation of reducing component A through a physical barrier effect. Tea polyphenol palmitate is a derivative obtained by lipophilic modification of polyphenolic compounds. While maintaining the hydrogen atom donor activity of the polyphenol hydroxyl structure, it introduces long-chain fatty acid ester groups, significantly improving lipophilicity, and its thermal decomposition temperature is significantly higher than that of ordinary tea polyphenols, allowing it to withstand the high-temperature impact of spray drying. Astragalus polysaccharide and tea polyphenol palmitate work synergistically to provide comprehensive high-temperature antioxidant protection at both the gas phase (hot air environment of spray drying) and liquid phase (microenvironment of feed liquid).

[0018] The carrier component C is modified hydrotalcite. Hydrotalcite has a typical layered double hydroxide structure with controllable interlayer spacing, high specific surface area, and strong adsorption and inclusion capacity. It can embed reducing components and high-temperature protective components into the interlayer pores to achieve slow release of functional components and avoid instantaneous depletion. At the same time, this invention functionalizes hydrotalcite to enable the carrier to actively participate in iron stabilization and anti-oxidation, rather than simply physical bearing.

[0019] Specifically, the modified hydrotalcite is prepared as follows: (1) Reducing anion intercalation modification A mixed salt solution with a total metal ion concentration of 0.5–2.0 mol / L is prepared by dissolving a divalent metal salt and a trivalent metal salt in deionized water at a molar ratio of 2:1 to 4:1; wherein the divalent metal salt includes Fe. 2+ Salts, including Mg 2+ Salt, Zn 2+ Salt or Ca 2+ At least one of the salts; and / or, the Fe 2+ The salt constitutes 10% to 50% of the total molar amount of the divalent metal salt; and / or, the divalent metal salt is at least one of a nitrate, chloride, or sulfate; and / or, the trivalent metal salt is Al. 3+ or Fe 3+ Nitrates, chlorides, or sulfates; Under a protective atmosphere (such as nitrogen), at 60–80°C and with rapid stirring, an alkaline solution containing reducing anions is mixed with a mixed salt solution, and the pH of the system is controlled at 8.0–11.0. After the addition is complete, the mixture is aged for 12–24 h. The alkaline solution contains 1.0–3.0 mol / L NaOH and 0.2–1.0 mol / L reducing anions. mol / L; the reducing anion is one or more of ascorbate, sulfite, metasulfite, gallate, catecholate, or cysteine; under the pH conditions of this invention, metal ions co-precipitate in the form of hydroxides to form layered double hydroxide crystal nuclei. During the co-precipitation process, the reducing anion is inserted in situ into the LDH interlayer as an interlayer charge compensation anion; and at a reaction temperature of 60~80℃, it is conducive to the full growth of LDH crystals and the orderly arrangement of interlayer anions. If the temperature is too high, the reducing anion may partially decompose. After aging, the crystal structure tends to be perfect and the interlayer anion exchange reaches equilibrium. The reaction product was centrifuged and washed until neutral, dried under vacuum at 60-80℃, ground and sieved (200-400 mesh) to obtain reduced anion-intercalated hydrotalcite; The inventors utilized the interlayer anion exchange properties of hydrotalcite to anchor reducing anions in situ within the confined space between layers, preventing the dissolution of free reducing agents and slowing their thermal decomposition at the high temperatures of spray drying. Simultaneously, the reducing anions in the interlayer can exchange substances with the external environment through interlayer channels, slowly releasing them into the liquid phase system, thus achieving continuous reduction of ferric ions. The ferrous ions in the layered structure provide intrinsic reducing activity, forming a dual reduction system with the intercalated anions.

[0020] (2) Ferrous ion lamination strengthening and surface coordination modification The hydrotalcite obtained in step (1) is dispersed in a solvent (e.g., deionized water) to prepare a suspension with a mass fraction of 3% to 8%. Under a protective atmosphere, a ferrous salt solution (Fe(NO3)2, FeSO4, or FeCl2, with a concentration of 0.1-0.5 mol / L) is added and stirred at 40-60°C for 2-4 h to allow ferrous ions to bind to the hydrotalcite through surface coordination or defect sites at the edge of the lamination. After the reaction is completed, the hydrotalcite is centrifuged, washed, and vacuum dried under a protective atmosphere to obtain ferrous-reinforced reduced hydrotalcite. The inventors based their work on the fact that the surface and lamellar edges of hydrotalcite nanocrystals contain a large number of unsaturated coordination sites and hydroxyl groups, which can adsorb Fe. 2+ And it is fixed by surface coordination bonds, the Fe introduced in this step 2+ Primarily distributed on the surface and edge defect sites of hydrotalcite, it possesses high chemical activity, allowing for rapid release and participation in reduction reactions within the liquid phase. Simultaneously, the Fe enriched on the surface... 2+ It can occupy active sites at the edge of the plate and inhibit other pro-oxidation metal ions (such as Cu). 2+ Fe 3+ Adsorption and catalysis in this region. Furthermore, Fe... 2+ Surface coordination modification can also increase the positive charge density on the surface of hydrotalcite and improve its electrostatic adsorption capacity for reducing anions.

[0021] (3) Surface hydrophobic modification The hydrotalcite obtained in step (2) is dispersed in a solvent (e.g., anhydrous ethanol) to prepare a suspension with a mass fraction of 5% to 15%. A hydrophobic silane coupling agent is added, and the mixture is refluxed at 60 to 80°C for 4 to 6 hours to allow the silane coupling agent to react with the hydroxyl groups on the surface and edges of the hydrotalcite through Si-OM bonds (M being the metal cation of the hydrotalcite layer). After the reaction, the mixture is centrifuged, washed, vacuum dried, ground, and sieved to finally obtain the modified hydrotalcite. The hydrophobic silane coupling agent is a fluorosilane (e.g., heptadecanofluorodecyltrimethoxysilane), a long-chain alkylsilane (e.g., octadecyltrimethoxysilane), or a vinylsilane, and its amount is 5% to 20% of the mass of the hydrotalcite obtained in step (2).

[0022] The surface of hydrotalcite is rich in hydroxyl groups, which can undergo condensation reactions with alkoxysilane coupling agents to form stable Si-OM covalent bonds. Hydrophobic groups (such as long-chain alkyl or fluorinated alkyl groups) are then grafted onto the surface of hydrotalcite. By modifying the surface of hydrotalcite to be hydrophobic, a hydrophobic barrier layer is constructed on the surface of hydrotalcite, reducing the adsorption and capillary aggregation of water molecules on the particle surface. The hydrophobic surface can also effectively block the direct contact between oxygen molecules in the air and the reducing active sites inside the hydrotalcite, reducing oxidative deactivation. The hydrophobically modified hydrotalcite can act as a hydrophobic isolation site in small peptide chelate ferrous products, breaking the hydrogen bond network between small peptide molecules. During spray drying, it can migrate and accumulate on the surface of droplets, forming a surface film with an interfacial barrier effect.

[0023] This invention also provides a method for preparing a highly stable chelated iron feed additive, comprising the following steps: S1. Disperse the carrier component C in a solvent (deionized water or ethanol-water mixed solvent) to prepare a saturated or supersaturated solution, add part of the reducing component A and part of the high temperature protection component B, stir and encapsulate at 45~55℃ for 3~5h, cool and crystallize, dry and pulverize to obtain a powdered molecular inclusion complex; This approach can accommodate the dispersion requirements of both water-soluble components (vitamin C, astragalus polysaccharide) and fat-soluble components (tea polyphenol palmitate), allowing the reducing component A and / or the high-temperature protective component B to combine with the modified hydrotalcite to form a complex through electrostatic adsorption, hydrogen bonding, hydrophobic interactions, and intercalation.

[0024] S2. The powdered molecular inclusion complex obtained in step S1 is mixed with the remaining reducing component A and high-temperature protective component B to prepare the feed additive.

[0025] In order to ensure the continuous and efficient function of reducing component A and high-temperature protective component B, the inventors added reducing component A and high-temperature protective component B in stages during preparation. Part of reducing component A and high-temperature protective component B were pre-encapsulated in modified hydrotalcite to obtain protection; the other part existed in free form and could be rapidly released during the liquid phase reaction stage to exert the reducing and antioxidant functions immediately. In this way, a dual protection mode of rapid effect and slow release can be formed.

[0026] Furthermore, the mass ratio of the amount of reducing component A added in S1 to the amount of reducing component A added in S2 is 3-4:1; the mass ratio of the amount of high-temperature protection component B added in S1 to the amount of high-temperature protection component B added in S2 is 3-4:1.

[0027] This invention also provides a method for preparing a highly stable chelated iron feed, comprising the following steps: A1: Preparation of small peptide solution: Protein raw materials are hydrolyzed, enzyme inactivated, centrifuged and dried to obtain small peptide powder, which is then mixed with water to prepare a small peptide solution with a mass concentration of 30%-40%. A2: Chelation reaction: Under a protective atmosphere (such as nitrogen), add a ferrous salt solution (ferrous sulfate or ferrous chloride, preferably ferrous sulfate) to the small peptide solution obtained in step A1. Adjust the pH to 4.5-6.0 using citric acid or sodium hydroxide solution, and stir the reaction at 40-50℃ for 0.5-2.0 h. 0.5-1.0 h after the reaction starts, add the above-mentioned feed additive (the mass of the feed additive accounts for 0.5%-2.0% of the mass of the small peptide powder), initially adding 60%-70% of the total amount. At this point, the chelation reaction has been initially established, and the small peptide-Fe... 2+ The formation of the chelate has consumed most of the Fe. 2+ Free Fe in the system 2+ At a low concentration, the addition of reducing component A will not significantly interfere with the chelation reaction; the mass ratio of ferrous ions to small peptide powder is 1:3-8, allowing the amino, carboxyl, and peptide bond nitrogen atoms in the small peptide molecules to fully react with Fe. 2+ Formation of coordination chelates, if Fe 2+ If the ratio is too high, there will be an excess of free Fe. 2+ Increased risk of oxidation; if Fe 2+ If the ratio is too low, the iron content of the product will be insufficient, which will affect the efficiency of feed addition. A3: High-temperature protection reinforcement: 0.5 hours before the end of step A2 reaction and before entering spray drying, add the remaining feed additives and stir evenly; To address the high-temperature failure issue in spray drying, the inventors added a feed additive 0.5 hours before the spray drying process. Leveraging the hydrophobic and activation-locking properties of hydrotalcite, this additive replenishes the system with a reducing component A and a high-temperature protective component B. The portion encapsulated in the modified hydrotalcite is continuously released at high temperatures, providing protection; the free portion increases the system's reducing capacity immediately before the feed enters the spray drying tower. If added too early, the free component is consumed or degraded before spray drying; if added too late, it cannot fully exert its protective effect during spray drying. This solves the problem of conventional antioxidants decomposing at high temperatures and lacking subsequent protection. A4: Spray drying: Spray dry the liquid obtained in step A3 with an inlet air temperature of 200-220℃ and an outlet air temperature of 100-120℃. Collect the dried powder to obtain chelated ferrous feed.

[0028] This invention divides reducing component A (vitamin C, reduced iron powder, and reduced glutathione) into two parts: one part is pre-loaded into modified hydrotalcite via molecular inclusion, and the other part exists in free form. During the chelation reaction stage, the free reducing component A rapidly disperses in the reaction system, immediately exerting its reducing effect, and converting existing or initially oxidized Fe in the system into Fe. 3+ Rapidly reduced to Fe 2+ The portion encapsulated within the modified hydrotalcite maintains a continuous reducing atmosphere in the system through slow release, compensating for the concentration decrease of free components due to chemical reactions. During the high-temperature shock stage of spray drying, free components may undergo partial thermal degradation, but the reducing components encapsulated between the hydrotalcite layers and on the surface are protected by the modified hydrotalcite layers and the protective layer formed by Astragalus polysaccharides at high temperatures, allowing them to continue to be released and exert their reducing effect. Simultaneously, the polyphenolic hydroxyl structure of tea polyphenol palmitate can efficiently scavenge free radical chain reactions at high temperatures. The combined use of Astragalus polysaccharides and tea polyphenol palmitate provides comprehensive high-temperature antioxidant protection at both the gas phase (hot air environment of spray drying) and liquid phase (feed liquid microenvironment). Furthermore, the added feed additives further supplement the system's reducing capacity, ensuring a sufficient supply of reducing components throughout the spray drying process.

[0029] Example 1 This embodiment provides a method for preparing modified hydrotalcite, as detailed below: (1) Mole ratio M 2+ M 3+ Weigh out FeSO4·7H2O, MgSO4·7H2O and Al2(SO4)3·18H2O in a ratio of 3:1, where Fe 2+ / (Fe 2+ +Mg 2+ The molar ratio of ) is 30%, which is dissolved in deionized water to prepare a mixed salt solution with a total metal ion concentration of 1.0 mol / L; Prepare a separate NaOH alkaline solution containing sodium ascorbate, wherein the NaOH concentration is 2.0 mol / L and the ascorbate concentration is 0.5 mol / L; Under nitrogen protection, at 70°C and with stirring, the mixed salt solution and alkaline solution were simultaneously added dropwise to the reactor, and the pH of the system was controlled at 9.5. After the addition was completed, the reactor was aged for another 18 hours. The reaction product was washed with deionized water by centrifugation until neutral, dried under vacuum at 70°C, and ground through a 300-mesh sieve to obtain ascorbate-intercalated hydrotalcite. (2) The above-mentioned hydrotalcite was dispersed in deionized water to prepare a suspension with a mass fraction of 5%. Under nitrogen protection, 0.2 mol / L FeSO4 solution was added and stirred at 50°C for 3 h. After the reaction was completed, the hydrotalcite was centrifuged under nitrogen protection, washed with deoxygenated water, and dried under vacuum at 50°C to obtain ferrous-enhanced reduced hydrotalcite. (3) Disperse the hydrotalcite obtained in step (2) in anhydrous ethanol to prepare a suspension with a mass fraction of 10%, add octadecyltrimethoxysilane in an amount of 10% of the mass of the hydrotalcite obtained in step (2), reflux at 70°C for 5 hours, centrifuge after the reaction, wash three times with anhydrous ethanol, vacuum dry at 50°C, and grind through a 300-mesh sieve to obtain modified hydrotalcite.

[0030] Example 2 The difference between this embodiment and Embodiment 1 is that in step (1), Fe 2+ The salt accounts for 50% of the total molar amount of the divalent metal salt; the reducing anion is gallate instead of ascorbate.

[0031] Example 3 The difference between this embodiment and embodiment 1 is that: in step (2), the ferrous salt solution is 0.5 mol / L ferrous chloride; in step (3), the silane coupling agent is heptadecafluorodecyltrimethoxysilane.

[0032] Example 4 This embodiment provides a highly stable chelated iron feed additive, comprising a reducing component A, a high-temperature protective component B, and modified hydrotalcite prepared in Example 1, in a mass ratio of 3:1.5:6; wherein the reducing component A comprises vitamin C, reduced iron powder, and reduced glutathione in a mass ratio of 2:1:0.4; and the high-temperature protective component B comprises astragalus polysaccharide and tea polyphenol palmitate in a mass ratio of 2:1.

[0033] The preparation method of the above feed additives is as follows: S1. Modified hydrotalcite was dispersed in deionized water to prepare a colloidal dispersion. 80% of reducing component A and 80% of high-temperature protective component B were added (the total amount of reducing component A and high-temperature protective component B was in the mass ratio of modified hydrotalcite to 4.5:5.5). The mixture was stirred at 50°C for 4 h to incorporate the components. After cooling and crystallization, the mixture was dried and pulverized to obtain a powdered molecular inclusion complex. S2. The above-mentioned powdered molecular inclusion complex powder is mixed with the remaining reducing component A and high-temperature protective component B to obtain the final feed additive.

[0034] Example 5 The difference between this embodiment and embodiment 4 is that the modified hydrotalcite prepared in embodiment 2 is used in S1.

[0035] Example 6 The difference between this embodiment and embodiment 4 is that the modified hydrotalcite prepared in embodiment 3 is used in S1.

[0036] Example 7 This embodiment provides a highly stable chelated iron feed, the preparation method of which is as follows: A1: Using soy protein isolate as raw material, the protein is enzymatically hydrolyzed with alkaline protease at pH 8.0 and 50℃ for 3 h, then the enzyme is inactivated at 90℃ for 10 min. The supernatant is collected by centrifugation and freeze-dried to obtain small peptide powder. The small peptide powder is then diluted with water to prepare a 35% small peptide solution. A2: Under a nitrogen protective atmosphere, add FeSO4·7H2O solution (Fe...) to the small peptide solution obtained in step A1. 2+ The feed additive prepared in Example 4 (1.5% of the peptide powder by mass) was added 0.5 h after the reaction started, with the pH adjusted to 5.5 by citric acid. The mixture was stirred at 65°C for 1.5 h. A3: After the reaction is complete and 0.5 h before spray drying, add the remaining 35% of the feed additive, stir well, and obtain the feed solution; A4: Spray dry the liquid obtained in step A3 with an inlet air temperature of 200℃ and an outlet air temperature of 120℃, and collect the dried powder to obtain chelated ferrous feed.

[0037] Example 8 The difference between this embodiment and embodiment 4 is that the feed additive prepared in embodiment 5 is used in S1.

[0038] Example 9 The difference between this embodiment and embodiment 4 is that the feed additive prepared in embodiment 6 is used in S1.

[0039] Comparative Example 1 The difference between this comparative example of hydrotalcite and Example 1 is that it does not include step (3); at the same time, the formulation and preparation method of the feed additive are the same as those in Example 4; and the feed is prepared using the method of Example 7.

[0040] Comparative Example 2 The difference between this comparative feed additive and Example 4 is that the hydrotalcite was not modified; ordinary Mg-Al hydrotalcite was used. Meanwhile, the feed was prepared using the method of Example 7.

[0041] Comparative Example 3 The difference between this comparative feed additive and Example 4 is that it does not include step S1, i.e., the reducing component A, the high-temperature protective component B, and the modified hydrotalcite are directly mixed. Meanwhile, the feed is prepared using the method of Example 7.

[0042] Comparative Example 4 The difference between this comparative feed additive and Example 4 is that it does not contain high-temperature protective component B. Meanwhile, the feed was prepared using the method of Example 7.

[0043] Comparative Example 5 The difference between this comparative feed and Example 7 is that it does not include step A3, meaning that all feed additives are added at once in step A2.

[0044] Experimental Example 1 The feed additives and feeds prepared in each of the embodiments and comparative examples were tested as follows: ① Retention rate of ferrous iron (%): Samples were taken before entering the spray drying process to determine the initial Fe content of the feed solution. 2+ Content; after spray drying, the solid feed powder was collected and tested again for Fe. 2+ Content; Retention rate = Fe content in dried feed powder 2+ Measured value / Fe in the liquid before drying 2+ Initial value × 100%; ② Moisture absorption resistance: Take 10.0 g of each spray-dried product from each example and comparative example, place them in a constant temperature and humidity chamber (temperature 40℃, relative humidity 75%), weigh the weight gain after 7 days, and calculate the moisture absorption weight gain rate (%) = (final mass - initial mass) / initial mass × 100%. At the same time, observe the appearance changes of the samples (whether they clump or change color). ③ Fe 2+ Residual rate: After the powdered feed was stored at room temperature in a sealed and dark place for 6 months, the proportion of residual active ferrous iron was determined. ④ Relative deviation of powder uniformity (%): Five parallel samples were randomly selected to determine Fe. 2+ Content, calculate the relative standard deviation of the detected value; the smaller the value, the more uniform the dispersion; the test results are shown in Table 1.

[0045] Table 1

[0046] As shown in Table 1, the overall performance of the feeds prepared in Examples 7-9 of this invention is significantly better than that of all comparative examples. The retention rate of divalent iron can be maintained at around 97%, and the hygroscopicity after 7 days of accelerated processing is less than 1.3%. This is mainly due to the hydrotalcite modification treatment and the slow-release structure formed by the gradient inclusion of S1 and S2, as well as the overall coupling of the two-stage addition process of chelation-drying during the feed preparation process. This significantly inhibits oxidation during the high-temperature spraying stage, results in low moisture absorption and weight gain, and has a small degree of activity decay during long-term storage, with uniform powder dispersion.

[0047] Comparison of Comparative Example 1 and Examples 7-9 shows that when hydrophobic grafting layers are lacking, water vapor and oxygen can easily penetrate into the particles due to the hydrophilic effect on the surface of hydrotalcite. On the one hand, the powder absorbs moisture and increases in weight significantly, and on the other hand, the interlayer reducing anions are more likely to be lost and degraded in the high-temperature aqueous environment. However, the hydrophobic barrier formed by hydrophobic modified hydrotalcite can significantly improve storage stability and high-temperature resistance.

[0048] Comparison of Comparative Example 2 and Examples 7-9 shows that ordinary hydrotalcite only plays a physical dispersing role, lacks interlayer reducing anions, surface ferrous micro-reduction sites and hydrophobic barrier layer, and cannot continuously stabilize ferrous iron under high temperature spray drying. The powder is extremely easy to absorb water, resulting in significant weight gain and a substantial decrease in activity after long-term storage. The comparison between Comparative Example 3 and Examples 7-9 shows that simple dry powder mixing lacks interlayer encapsulation and sustained-release effects. All antioxidant components exposed to the aqueous phase may undergo rapid dissolution and premature depletion. During the spray drying stage, there is a lack of continuous replenishment of protective activity, high-temperature deterioration is aggravated, and the uniformity of each batch is worse. It can be seen that the processing technology of encapsulation before compounding is of great help to enable feed additives to achieve both rapid and sustained-release effects.

[0049] The comparison between Comparative Example 4 and Examples 7-9 shows that the reducing component alone cannot resist instantaneous high-temperature thermal degradation. The synergistic effect of Astragalus polysaccharide and tea polyphenol palmitate in this invention can form a heat-resistant protective film, inhibit the thermal decomposition of the reducing component, significantly improve the ferrous iron retention rate after spray drying, and make up for the shortcomings of the simple reducing system which is effective at low temperatures but fails at high temperatures.

[0050] The comparison between Comparative Example 5 and Examples 7-9 shows that: if all feed additives are added at once, the antioxidants may be consumed in large quantities in the early liquid phase stage, resulting in insufficient protection when entering the spray drying process; while adding them in batches can strengthen the protection before the arrival of high temperature and achieve continuous stability throughout the process.

[0051] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A highly stable chelated iron feed additive, characterized in that, It includes a reducing component A, a high-temperature protective component B, and a carrier component C in a mass ratio of 2~4:1~2:5~8, wherein: The reducing component A includes vitamin C, and the high-temperature protective component B includes astragalus polysaccharide and tea polyphenol palmitate; The carrier component C is modified hydrotalcite, and at least a portion of the reducing component A and / or the high-temperature protective component B are encapsulated within the carrier component C to form a molecular inclusion complex.

2. The high-stability chelated iron feed additive according to claim 1, characterized in that, The reducing component A also includes at least one of reduced iron powder and reduced glutathione; And / or, the mass ratio of vitamin C to reduced iron powder is 2~5:1; And / or, the mass ratio of the vitamin C to the reduced glutathione is 1:0.2~0.

5.

3. The high-stability chelated iron feed additive according to claim 1, characterized in that, In the high-temperature protection component B, the mass ratio of Astragalus polysaccharide to tea polyphenol palmitate is 1~3:

1.

4. The high-stability chelated iron feed additive according to claim 1, characterized in that, The modified hydrotalcite is prepared as follows: (1) Mix and dissolve divalent and trivalent metal salts to form a mixed salt solution with a total metal ion concentration of 0.5~2.0 mol / L; Under a protective atmosphere and with stirring, an alkaline solution containing reducing anions is mixed with a mixed salt solution, and the pH of the system is controlled at 8.0~11.

0. After the addition is complete, aging continues. The reaction product was centrifuged, washed, vacuum dried, ground and sieved to obtain reduced anion-intercalated hydrotalcite. (2) Disperse the hydrotalcite obtained in step (1) in a solvent to form a suspension. Add ferrous salt solution under a protective atmosphere to react. After the reaction is completed, centrifuge, wash and vacuum dry under a protective atmosphere to obtain ferrous-enhanced reduced hydrotalcite. (3) Disperse the hydrotalcite obtained in step (2) in a solvent to form a suspension, add a hydrophobic silane coupling agent to react; after the reaction is completed, centrifuge, wash, vacuum dry, grind and sieve to finally obtain the modified hydrotalcite.

5. The high-stability chelated iron feed additive according to claim 1, characterized in that, In step (1), the divalent metal salt includes Fe. 2+ Salts, including Mg 2+ Salt, Zn 2+ Salt or Ca 2+ At least one of the salts; And / or, the Fe 2+ Salts comprise 10% to 50% of the total molar amount of divalent metal salts; And / or, the divalent metal salt is at least one of a nitrate, a chloride, or a sulfate; And / or, the trivalent metal salt is Al 3+ or Fe 3+ Nitrates, chlorides, or sulfates.

6. The high-stability chelated iron feed additive according to claim 1, characterized in that, In step (1), the reducing anion is one or more of ascorbic acid, sulfite, metasulfite, gallate, catecholate or cysteine. And / or, in step (1), the concentration of NaOH in the alkaline solution is 1.0~3.0 mol / L, and the concentration of reducing anions is 0.2~1.0 mol / L.

7. The high-stability chelated iron feed additive according to claim 1, characterized in that, In step (3), the hydrophobic silane coupling agent is one or more of fluorinated silane, long-chain alkyl silane or vinyl silane, and its amount is 5% to 20% of the mass of the hydrotalcite obtained in step (2).

8. A method for preparing a highly stable chelated iron feed additive according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Disperse the carrier component C in a solvent to prepare a saturated or supersaturated solution, add part of the reducing component A and part of the high-temperature protective component B, carry out the inclusion reaction, cool down to crystallize, dry and pulverize to obtain a powdered molecular inclusion complex; S2. The powdered molecular inclusion complex obtained in step S1 is mixed with the remaining reducing component A and high-temperature protective component B to prepare the feed additive.

9. The method for preparing the highly stable chelated iron feed additive according to claim 8, characterized in that, The mass ratio of the amount of reducing component A added in S1 to the amount of reducing component A added in S2 is 3-4:1; the mass ratio of the amount of high-temperature protection component B added in S1 to the amount of high-temperature protection component B added in S2 is 3-4:

1.

10. A method for preparing a highly stable chelated iron feed, characterized in that, Includes the following steps: A1. Protein raw materials are hydrolyzed, enzyme-inactivated, centrifuged, and dried to obtain small peptide powder, which is then mixed with water to prepare a small peptide solution. A2. Under a protective atmosphere, add a ferrous salt solution to the small peptide solution obtained in step A1, adjust the pH to 4.5-6.0, and react for a period of time; 0.5-1.0 h after the reaction starts, add a portion of the feed additive as described in any one of claims 1-7 or the feed additive prepared by the preparation method described in any one of claims 8-9. A3. 0.5 hours before the end of the reaction in step A2 and before spray drying, add the remaining feed additives, stir well, and obtain the liquid. A4. Spray dry the liquid obtained in step A3, collect the dried powder, and obtain the feed.

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