A double-layer slow-release feed antioxidant based on superfine ginger powder and a preparation method thereof

Abstract

The application provides a double-layer slow-release feed antioxidant based on superfine ginger powder and a preparation method thereof. The ginger powder is crushed to superfine particle size through a superfine crushing technology, the cell wall barrier is broken, and the dissolution efficiency and bioavailability of active ingredients are improved. The chitosan is modified by using a silane grafting modification technology, an inner layer coating with excellent hydrophobicity, water resistance and mechanical strength is constructed, a hydrophilic outer layer coating is constructed in combination with sodium alginate, a double-layer coating structure of "inner hydrophobic-outer hydrophilic" is formed, the protection of active ingredients such as gingerols in a gastric acid environment and the targeted slow release in an intestinal environment are realized, meanwhile, the palatability and storage stability of the product are improved by reasonably matching the components, and finally, a safe, efficient, stable and controllable natural feed antioxidant is obtained, technical defects existing in the prior art ginger powder feed antioxidant are solved, and the demand of large-scale livestock and poultry breeding is met.

Description

Technical Field

[0001] This invention relates to the field of feed additive technology, specifically to a double-layer slow-release feed antioxidant based on ultrafine ginger powder and its preparation method. Background Technology

[0002] In modern large-scale livestock and poultry farming, animals face various adverse factors such as environmental stress (e.g., high temperature, low temperature, overcrowding), feed spoilage, and transportation stress, which can easily trigger oxidative stress responses in the body. Oxidative stress leads to the excessive accumulation of reactive oxygen species (ROS) in the animal's body, damaging the structure of cellular lipids, proteins, and nucleic acids, thereby causing a decline in animal production performance, impaired immune function, and deterioration in meat quality. It also accelerates animal aging, shortens the breeding cycle, and causes huge economic losses to the livestock industry. Therefore, alleviating oxidative stress in animals and maintaining the body's oxidation-antioxidant balance is a key link in ensuring healthy livestock and poultry farming and improving farming efficiency.

[0003] Adding antioxidants to animal feed is one of the most direct and effective ways to alleviate oxidative stress in animals. Currently, commonly used antioxidants in the feed industry are mainly divided into two categories: synthetic antioxidants and natural plant antioxidants. Synthetic antioxidants (such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and tert-butylhydroquinone (TBHQ)) have advantages such as strong antioxidant effects, low cost, and ease of processing, and were once widely used. However, with increasing public concern about the safety of livestock products, the residual risks and potential toxicity of synthetic antioxidants have become increasingly prominent. They are metabolized slowly in animals and easily remain in tissues such as muscles, liver, and kidneys, and can be passed to humans through the food chain. Long-term intake may lead to chronic poisoning, cancer, teratogenicity, and other health risks. Therefore, the use of synthetic antioxidants is subject to increasingly strict restrictions, and some countries and regions have banned their use in feed.

[0004] In contrast, natural plant antioxidants, derived from natural plants, are safe, residue-free, and non-toxic, possessing multiple physiological functions such as anti-oxidation, anti-inflammation, and immune regulation. They have become a research hotspot in the field of feed antioxidants in recent years. Ginger, a natural plant used both as food and medicine, is widely cultivated in my country and around the world, with abundant resources and low cost. Its main active components are gingerol compounds (including 6-gingerol, 8-gingerol, 10-gingerol, etc.), shogaol compounds, curcumin, and zingiberene. Among these, gingerol and shogaol are the main antioxidant active components, possessing a strong ability to scavenge free radicals and inhibit lipid peroxidation. They can also regulate the balance of intestinal flora in animals, promote nutrient absorption, and enhance the body's immunity, showing broad application prospects in the feed industry.

[0005] However, directly applying ordinary ginger powder, processed from fresh ginger, to animal feed suffers from numerous technical defects due to its inherent characteristics and the effects of processing, storage, and digestion, severely limiting its application effectiveness. Specifically: 1. Extremely low bioavailability: The particle size of ordinary ginger powder is usually around 80-120 mesh, which is relatively large and has a small specific surface area. In addition, the cell wall of ginger is a dense structure composed of cellulose and hemicellulose. Active ingredients such as gingerol are wrapped inside the cell wall and are difficult to dissolve quickly in the animal digestive tract. Most of the active ingredients are excreted with feces, resulting in extremely low absorption rate by animals and failure to fully exert its antioxidant effect.

[0006] 2. Poor stability of active ingredients: Gingerol and other active ingredients are heat-sensitive and photosensitive substances, which are extremely sensitive to external environmental factors such as light, heat, humidity, and oxygen. They are prone to degradation and inactivation during feed processing (such as pelleting, extrusion, and drying, where the temperature is usually between 80 and 120°C). During storage, they are also prone to oxidation and decomposition due to moisture absorption and light exposure, resulting in a significant decrease or even complete loss of their antioxidant activity.

[0007] 3. Uncontrollable release process: In the acidic environment of the stomach (pH 1.2-3.0) of an animal, the active ingredients of ordinary ginger powder are easily and rapidly dissolved and degraded by the stomach acid. As a result, very few active ingredients reach the intestinal absorption site (the main site of nutrient absorption in animals), making it impossible to achieve targeted release and difficult to achieve the expected antioxidant effect. At the same time, the rapid release of active ingredients in the stomach may also irritate the gastric mucosa and cause gastrointestinal discomfort in animals.

[0008] 4. Poor palatability: Ginger has a strong spicy taste. Adding it directly to feed will change the flavor of the feed and stimulate the taste buds of animals. In particular, it will significantly reduce the feed intake of young animals such as piglets and chicks, thereby affecting their growth and development.

[0009] To address the aforementioned issues, existing technologies employ microencapsulation to process ginger powder. This involves coating the ginger powder with a wall material to protect and regulate the release of active ingredients. However, current ginger powder microcapsule technologies are mostly single-layer coating structures. Commonly used wall materials include natural polymers such as sodium alginate, chitosan, gelatin, and gum arabic. These single-layer microcapsules have significant technical limitations: First, the wall material has high porosity and poor water resistance, making it prone to absorbing water and rupturing in the acidic environment of the stomach, leading to premature release of active ingredients and preventing intestinal targeting. Second, natural polymer wall materials (such as chitosan) are highly hydrophilic, making it difficult to form effective water and oxygen barriers, thus failing to effectively protect active ingredients such as gingerol from moisture and oxygen, resulting in poor storage stability. Third, the wall material lacks sufficient mechanical strength, making it prone to breakage during feed pelleting, extrusion, and other processing, leading to leakage and inactivation of the encapsulated active ingredients.

[0010] Therefore, in response to the shortcomings of existing technologies such as low bioavailability, poor stability of active ingredients, and uncontrollable release of ordinary ginger powder, as well as the insufficient wall material performance and poor targeted sustained-release effect of existing microencapsulation coating technology, it is crucial to develop a ginger powder feed antioxidant that can effectively protect active ingredients such as gingerol from damage caused by processing, storage, and gastric acid environment, achieve targeted sustained release in the intestine, possess excellent mechanical strength and storage stability, and improve palatability. This is a pressing technical challenge in the current feed additive field and a key to promoting the large-scale application of natural plant antioxidants in the feed industry. Summary of the Invention

[0011] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a double-layer slow-release feed antioxidant based on ultrafine ginger powder and its preparation method. Ultrafine grinding technology is used to pulverize ginger powder to an ultrafine particle size, breaking down cell wall barriers and improving the dissolution efficiency and bioavailability of active ingredients. Chitosan is modified using silane grafting modification technology to construct an inner coating with excellent hydrophobicity, water resistance, and mechanical strength. A hydrophilic outer coating is constructed by combining sodium alginate, forming a "hydrophobic inside, hydrophilic outside" double-layer coating structure, achieving protection of active ingredients such as gingerol in the gastric acid environment and targeted slow release in the intestinal environment. Simultaneously, by rationally proportioning the components, the palatability and storage stability of the product are improved, ultimately resulting in a safe, efficient, stable, and controllable natural feed antioxidant. This addresses the technical deficiencies of existing ginger powder feed antioxidants and meets the needs of large-scale livestock and poultry farming.

[0012] To solve the above-mentioned technical problems, the present invention provides a double-layer slow-release feed antioxidant based on ultrafine ginger powder, which consists of a core particle and a double-layer coating layer; the core particle is ultrafine ginger powder; the double-layer coating layer consists of a hydrophobic and water-blocking layer formed by solidification of silane-grafted modified chitosan and a hydrophilic dispersion layer formed by solidification of sodium alginate from the inside to the outside; the crosslinking agent used for solidification is sodium tripolyphosphate or calcium chloride.

[0013] In a preferred embodiment, the particle size distribution of the ultrafine ginger powder is: D 50 =5~15μm.

[0014] In a preferred embodiment, the silane-grafted modified chitosan is prepared by reacting chitosan with a silane coupling agent in an acetic acid solution; the silane coupling agent is γ-aminopropyltriethoxysilane KH550 or γ-epoxypropoxypropyltrimethoxysilane KH570, and the amount added is 1-5% of the mass of chitosan.

[0015] In a preferred embodiment, based on 100 parts by weight of ultrafine ginger powder, the modified chitosan content in the hydrophobic and water-blocking layer is 15-25 parts, the sodium alginate content in the hydrophilic dispersion layer is 20-30 parts, and the total crosslinking agent content is 0.5-2 parts.

[0016] In a preferred embodiment, the antioxidant further comprises a plasticizer, wherein the plasticizer is propylene glycol or glycerin, and the amount used is 1 to 5% of the weight of ginger powder.

[0017] The present invention also provides a method for preparing the above-mentioned double-layer slow-release feed antioxidant based on ultrafine ginger powder, which includes the following steps: (1) Preparation of ultrafine ginger powder: Wash and slice fresh ginger, dry it until the moisture content is ≤5%, and coarsely grind it to D. 50 =125~250 μm, then subjected to airflow ultrafine pulverization to D 50 =5~15 μm; (2) Wall material modification: Chitosan is dissolved in acetic acid solution, and silane coupling agent is added and reacted at 40-60℃ for 2-4 hours to obtain silane grafted modified chitosan solution; (3) Core formation: Ultrafine ginger powder is dispersed in sodium alginate solution, and calcium chloride solution is added dropwise to cross-link and solidify, thus obtaining ginger powder core; (4) Inner coating: The pellet core is placed in a modified chitosan solution and cross-linked and cured with sodium tripolyphosphate to form a hydrophobic and water-blocking layer; (5) Outer coating: The inner coating particles are immersed in sodium alginate solution and cross-linked and solidified again to form a hydrophilic dispersion layer; (6) Drying and collection: Dry at 50-60℃ until the moisture content is <5%, and then sieve to obtain the finished product.

[0018] In a preferred embodiment, the acetic acid solution has a mass percentage concentration of 1% and the chitosan solution has a mass percentage concentration of 1-3% in step (2).

[0019] In a preferred embodiment, the calcium chloride solution in step (3) has a mass percentage concentration of 1-5%, a cross-linking curing time of 1-2 hours, and a core particle size controlled at 0.8-1.2 mm.

[0020] In a preferred embodiment, the amount of sodium tripolyphosphate used in step (4) is 5-10% of the mass of the modified chitosan, and the crosslinking time is 1-2 hours.

[0021] The present invention also provides the application of the antioxidant in the preparation of livestock or aquatic feed that improves the antioxidant capacity, growth performance and palatability of animals.

[0022] Beneficial effects of the present invention Compared with the prior art, the technical solution provided by the present invention has the following significant advantages: Ultrafine grinding enhances synergistic effects and significantly improves bioavailability: This invention utilizes airflow ultrafine grinding technology to pulverize ginger powder to a D50 of 5–15 μm. Compared to ordinary ginger powder, its specific surface area is significantly increased, completely breaking down the cell wall barrier of ginger and fully exposing active ingredients such as gingerol. This effectively solves the problems of slow dissolution rate and low absorption rate of active ingredients in traditional ginger powder. Experiments have confirmed that the ultrafine ginger powder of this invention has a significantly higher gingerol dissolution rate than ordinary ginger powder, thereby significantly increasing the absorption rate of gingerol by animals and fundamentally improving the antioxidant effect and bioavailability of ginger powder. At the same time, the uniform and delicate particle size of the ultrafine ginger powder can effectively reduce the spiciness of ginger, improve the palatability of the product, and avoid a decrease in animal feed intake due to spiciness.

[0023] The dual-layer structure enables precise targeted sustained release, achieving "gastric-avoidance intestinal release": This invention constructs a dual-layer coating structure of "inner hydrophobic and outer hydrophilic," achieving precise regulation of the release of active ingredients in the gastrointestinal tract. The inner layer, silane-modified chitosan, possesses excellent hydrophobicity and acid resistance, effectively blocking the erosion of gastric acid (pH 1.2-3.0) and preventing premature release and degradation of active ingredients in the stomach. Experiments show that the release rate of this product in simulated gastric fluid is <15% after 2 hours, significantly lower than ordinary ginger powder and single-layer coated products. The outer layer, sodium alginate, has good hydrophilicity and can rapidly swell in the alkaline environment of the intestine (pH 6.8-7.4), causing the inner coating to gradually dissolve and release the active ingredients in the core, achieving targeted release in the intestine. The cumulative release rate in simulated intestinal fluid after 12 hours is >60%, ensuring that the active ingredients are fully released at the absorption site and efficiently absorbed and utilized by the animal body, maximizing their antioxidant effects.

[0024] Silane modification enhances the performance of the coating material, improving storage stability and mechanical strength: This invention modifies chitosan through silane grafting modification technology, introducing hydrophobic organosiloxane segments onto the chitosan molecular chain. This significantly reduces the hydrophilicity of the coating material, constructing an effective water and oxygen barrier, while simultaneously enhancing the mechanical strength and flexibility of the coating film. Experiments show that compared to unmodified chitosan, the water vapor permeability of the silane-modified coating film is reduced by more than 40%, and the oxygen permeability is significantly reduced, effectively preventing moisture and oxygen from entering the core and protecting active ingredients such as gingerol from oxidative degradation. After storage for 30 days under high temperature and high humidity conditions (40℃, 75%RH), the gingerol retention rate of this product reaches over 89%, which is more than 20% higher than the unmodified chitosan-coated product and more than 60% higher than ordinary ginger powder. Meanwhile, the modified coating film has significantly improved mechanical strength, with a compressive strength of 15-20N. During feed pelleting (temperature 80-120℃, pressure 10-15MPa) and extrusion processes, the breakage rate is less than 5%, which is much lower than that of single-layer coated products, and can meet the needs of large-scale feed processing.

[0025] Safe and residue-free, with multiple physiological functions: The product of this invention uses natural ginger as raw material, and the wall material is made of food-grade modified chitosan and sodium alginate. The plasticizer and cross-linking agent are all food-grade materials with no toxic side effects. The entire preparation process does not add any toxic or harmful substances, making the product safe and residue-free, meeting the safety requirements for feed additives in modern livestock and poultry farming. At the same time, active ingredients such as gingerol not only have excellent antioxidant effects, but also regulate the balance of animal intestinal flora, promote intestinal peristalsis, and improve the absorption efficiency of nutrients; enhance the animal's immune function and improve disease resistance; and improve the quality of livestock products, making the meat color more vibrant, the flavor richer, and reducing drip loss. It has multiple physiological functions of "antioxidant + growth promotion + quality improvement".

[0026] The preparation process is simple, low-cost, and easy to scale up: The preparation process of this invention uses conventional equipment such as ultrafine grinding, solution preparation, coating, and drying. The process steps are simple and easy to operate, without the need for complex special equipment. The raw materials are abundant and low-cost, and no wastewater, waste gas, or waste residue is generated during the preparation process, making it green and environmentally friendly. The product has good stability, a long storage period, and is easy to transport and apply, making it suitable for large-scale production and promotion.

[0027] Wide range of applications and broad application prospects: The products of this invention can be widely used in the feed of livestock and poultry such as broilers, laying hens, pigs, beef cattle, and sheep, as well as aquatic animals such as fish, shrimp, and crabs. The amount added can be flexibly adjusted according to the different growth stages and breeding needs of different animals, and can achieve good antioxidant and growth-promoting effects, with broad market application prospects. Detailed Implementation

[0028] This invention provides a double-layered slow-release feed antioxidant based on ultrafine ginger powder, comprising a core particle and a coating layer. The core particle is ultrafine ginger powder, whose main active ingredients are gingerol, shogaol, and other inherent active substances of ginger, as well as dietary fiber, minerals, and other nutrients found in ginger. The coating layer has a double-layer structure, consisting of a hydrophobic water-blocking layer and a hydrophilic dispersion layer from the inside out. The two coating layers are tightly bonded together to form a complete protection and slow-release system. The hydrophobic water-blocking layer is formed by silane-grafted modified chitosan and cured with a cross-linking agent. Its main function is to block gastric acid, water, and oxygen, protecting the active ingredients in the core from premature release and degradation. The hydrophilic dispersion layer is formed by cross-linking sodium alginate and cured with a cross-linking agent. Its main function is to improve the product's dispersibility in water, facilitating uniform mixing with feed, and to swell in the alkaline environment of the intestine, promoting the dissolution of the inner coating and the release of active ingredients. The cross-linking agent is sodium tripolyphosphate (TPP) or calcium chloride, used to induce a cross-linking reaction between the wall material molecules, forming a structurally stable coating film with high mechanical strength.

[0029] The particle size distribution of the ultrafine ginger powder is: D 50 The particle size is 5–15 μm. Ultrafine ginger powder in this particle size range has a specific surface area 10–30 times that of ordinary ginger powder, which can completely break down the cell wall structure of ginger, allowing active ingredients such as gingerol to be fully exposed and significantly increasing their dissolution rate in the digestive tract. At the same time, ginger powder particles of this size are uniform, facilitating subsequent coating processes and reducing the release of spiciness, thus improving the palatability of the product. If the particle size D… 50 If the particle size is greater than 15 μm, the cell wall cannot be sufficiently broken, resulting in low dissolution efficiency of active ingredients and insufficient bioavailability; if the particle size D... 50 If the particle size is less than 5μm, the ginger powder particles are prone to agglomeration, making it difficult to disperse evenly and significantly increasing processing costs, which is not conducive to large-scale production.

[0030] The preparation method of the silane-grafted modified chitosan is as follows: chitosan is dissolved in an acetic acid solution with a mass percentage concentration of 1% to 2%, and stirred until completely dissolved to obtain a chitosan solution with a mass percentage concentration of 1% to 3%; then a silane coupling agent is added, the amount of silane coupling agent added is 1% to 5% of the mass of chitosan, and after stirring evenly, it is reacted in a constant temperature water bath at 40 to 60°C for 2 to 4 hours. During the reaction, the mixture is continuously stirred to ensure that the silane coupling agent and chitosan are fully grafted together; after the reaction is completed, the product is washed with deionized water 3 to 5 times to remove unreacted silane coupling agent and acetic acid, and then vacuum dried at 50 to 60°C to constant weight. After pulverization, silane-grafted modified chitosan powder is obtained.

[0031] The silane coupling agent is selected from γ-aminopropyltriethoxysilane KH550 or γ-epoxypropoxypropyltrimethoxysilane KH570. These two silane coupling agents have good reactivity and can undergo grafting reactions with the amino and hydroxyl groups on the chitosan molecular chain to introduce hydrophobic organosiloxane segments into the chitosan molecular chain, thereby significantly reducing the hydrophilicity of chitosan and improving its water and oxygen barrier properties. At the same time, it enhances the mechanical strength and flexibility of the coating film and avoids damage during feed processing.

[0032] Based on 100 parts by weight of ultrafine ginger powder, the amount of modified chitosan in the hydrophobic and water-blocking layer is 15-25 parts, the amount of sodium alginate in the hydrophilic dispersion layer is 20-30 parts, and the amount of crosslinking agent is 0.5-2 parts. This dosage ratio was optimized through extensive experiments. It ensures both the thickness and integrity of the coating film, achieving effective protection and targeted sustained release of the active ingredients, while avoiding excessive wall material usage leading to increased product costs and reduced proportion of active ingredients, or insufficient wall material usage resulting in incomplete coating and poor sustained release effect. Specifically, when the amount of modified chitosan is less than 15 parts, the thickness of the hydrophobic and water-blocking layer is insufficient, failing to effectively block gastric acid and water, and the active ingredients are easily released prematurely; when the amount exceeds 25 parts, the coating film is too thick, which will hinder the release of active ingredients in the intestine and reduce bioavailability. When the amount of sodium alginate is less than 20 parts, the hydrophilic dispersion layer effect is poor, and the product is unevenly dispersed in the feed. When the amount exceeds 30 parts, the mechanical strength of the coating film will decrease, and it may lead to an excessively rapid intestinal release rate, failing to achieve the sustained-release effect. When the amount of crosslinking agent is less than 0.5 parts, the wall material crosslinking is insufficient, the coating film structure is loose, and it is easily damaged. When the amount exceeds 2 parts, the crosslinking is excessive, the coating film is too dense, and the active ingredients cannot be released normally.

[0033] The antioxidant also includes a plasticizer, selected from propylene glycol or glycerin, used at 1-5% of the ginger powder weight. The plasticizer improves the flexibility and plasticity of the coating film, reducing its brittleness during processing and storage, and preventing cracking and damage. Simultaneously, the plasticizer promotes the bonding between wall material molecules, improving the integrity and water-blocking properties of the coating film. Propylene glycol and glycerin are both food-grade, non-toxic plasticizers with good compatibility with modified chitosan and sodium alginate, and will not affect the product's safety or antioxidant effect. If the plasticizer dosage is less than 1%, the coating film will lack flexibility and be easily damaged; if the dosage exceeds 5%, it will increase the hydrophilicity of the coating film, reduce its water-blocking effect, and may affect the product's stability.

[0034] The present invention also provides a method for preparing the above-mentioned double-layer slow-release feed antioxidant based on ultrafine ginger powder, comprising the following steps: Step 1, Preparation of Ultrafine Ginger Powder: Select fresh ginger that is free from rot and pests, wash away surface mud and impurities with clean water, slice it into thin slices 2-3 mm thick, and place them in an oven to dry at 60-70℃ until the moisture content is ≤5%. Excessive moisture content will cause particle agglomeration during subsequent ultrafine grinding and easily breed microorganisms, affecting product stability. Place the dried ginger slices into a coarse grinder and coarsely grind them to D... 50 =125~250 μm, to obtain coarse ginger powder; then the coarse ginger powder is fed into an airflow ultrafine pulverizer, the pulverizing pressure is adjusted to 0.6~0.8MPa, the pulverizing time is 10~20 minutes, and the particle size is pulverized to D. 50 The particle size is 5-15 μm to obtain ultrafine ginger powder. The ultrafine ginger powder is then sieved to remove impurities and large particles, and sealed for later use. Among these, airflow ultrafine pulverization technology has the advantages of high pulverization efficiency, uniform particle size, no impurity contamination, and maximum retention of active ingredients, while avoiding the degradation and inactivation of gingerol caused by the high temperature generated during traditional mechanical pulverization.

[0035] The second step is wall material modification: Chitosan is dissolved in a 1% (w / w) acetic acid solution and stirred until completely dissolved to obtain a 2% (w / w) chitosan solution. 1-5% (w / w) of silane coupling agent is added to the chitosan solution, and after stirring evenly, the solution is placed in a constant temperature water bath at 40-60℃ and reacted for 2-4 hours, stirring every 30 minutes to ensure complete reaction. After the reaction, the product is poured into deionized water and washed 3-5 times with stirring until the washing solution is neutral (pH 6.5-7.5) to remove unreacted silane coupling agent and acetic acid. The washed product is placed in a vacuum drying oven and vacuum dried at 50-60℃ to constant weight. After pulverization, silane-grafted modified chitosan powder is obtained. The modified chitosan powder is dissolved in deionized water and stirred until completely dissolved to obtain a 1.5%-2.5% (w / w) modified chitosan solution for later use.

[0036] The third step is core formation: Prepare a sodium alginate solution with a mass percentage concentration of 1%–3%. Disperse ultrafine ginger powder in the sodium alginate solution at a solid-liquid ratio of 1:2–1:4 (g / mL). Stir with a high-speed stirrer for 30–60 minutes at a stirring speed of 1000–1500 r / min to obtain a uniform ginger powder-sodium alginate suspension. Pour the suspension into a dropping device and adjust the dropping speed to 30–50 drops / min. Add the suspension to a 1%–5% sodium alginate solution. Add the sodium alginate to the calcium chloride solution and let it stand for 1-2 hours to allow the sodium alginate to cross-link with the calcium chloride, solidifying to form spherical ginger powder pellets. Remove the pellets from the calcium chloride solution and wash them 2-3 times with deionized water to remove residual calcium chloride from the surface. Drain the water and set aside. The particle size of the pellets should be controlled between 0.8 and 1.2 mm. This particle size ensures the uniformity of subsequent coating, facilitates mixing with feed, and avoids excessively large particle size leading to a slow intestinal release rate, or excessively small particle size leading to easy loss during the coating process.

[0037] Step 4, Inner Coating: The ginger powder core prepared in Step 3 is placed into the modified chitosan solution obtained in Step 2. Sodium tripolyphosphate is added as a cross-linking agent, with the amount of sodium tripolyphosphate being 5%–10% of the mass of the modified chitosan. After stirring evenly, the mixture is allowed to stand at room temperature for 1–2 hours for cross-linking, allowing the modified chitosan to form a uniform and dense hydrophobic and water-blocking layer on the surface of the core. After cross-linking, the particles are removed and washed 1–2 times with deionized water to remove uncross-linked modified chitosan and sodium tripolyphosphate from the surface. The particles are then drained and set aside. The thickness of the inner coating is controlled at 0.1–0.2 mm to ensure effective barrier against gastric acid and water, while avoiding excessive thickness that could affect the subsequent outer coating and intestinal release.

[0038] Step 5, outer coating: Prepare a sodium alginate solution with a mass percentage concentration of 1%–2%. Immerse the particles with the inner coating obtained in Step 4 into the sodium alginate solution for 30–60 minutes to allow the sodium alginate to be uniformly adsorbed on the particle surface. Then, add a small amount of calcium chloride as a cross-linking agent, stir evenly, and let it stand to solidify for 30–45 minutes, allowing the sodium alginate to undergo a cross-linking reaction on the surface, forming a uniform hydrophilic dispersion layer. After solidification, remove the particles, wash them 1–2 times with deionized water to remove residual sodium alginate and calcium chloride, and drain the water for later use. The thickness of the outer coating should be controlled at 0.05–0.1 mm, which can improve the dispersibility of the product and allow it to swell rapidly in the intestinal environment, promoting the dissolution of the inner coating and the release of active ingredients.

[0039] Step 6, Drying and Collection: Place the coated granules from Step 5 into an oven and dry them at 50-60℃ until the moisture content is <5%. If the moisture content is too high, the product will absorb moisture and mold during storage, affecting its stability. After drying, sieve the product using a standard sieve to remove oversized and undersized granules, obtaining a final product with uniform particle size. Seal the product in a sealed package and store it in a cool, dry, and ventilated environment for later use.

[0040] The following examples illustrate the implementation of the present invention in detail, thereby enabling a full understanding and implementation of how the present invention uses technical means to solve technical problems and achieve technical effects.

[0041] Source of raw materials Fresh ginger: Commercially available fresh ginger, produced in Shandong, washed, sliced, and free from rot and pests; Chitosan: food grade, degree of deacetylation ≥90%, viscosity 50-200 mPa·s, purchased from Shandong Aokang Biotechnology Co., Ltd. Sodium alginate: food grade, viscosity 200-400 mPa·s, purchased from Qingdao Mingyue Algae Group Co., Ltd. Silane coupling agents: KH550 (γ-aminopropyltriethoxysilane) and KH570 (γ-epoxypropoxypropyltrimethoxysilane), industrial grade, purchased from Nanjing Shuguang Chemical Group Co., Ltd. Crosslinking agents: sodium tripolyphosphate (TPP) and calcium chloride (CaCl2), food grade, purchased from Sinopharm Chemical Reagent Co., Ltd. Plasticizers: propylene glycol and glycerin, food grade, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Other reagents: Acetic acid, analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd.; deionized water, prepared in-house.

[0042] Detection methods Gingerol content determination: High performance liquid chromatography (HPLC) was used, referring to GB / T 29058-2012 "Determination of gingerol compounds in ginger and its products", to determine the total amount of 6-gingerol and 8-gingerol. Chromatographic conditions: C18 column (250 mm × 4.6 mm, 5 μm); mobile phase: methanol-water (60:40 v / v); flow rate: 1.0 mL / min; detection wavelength: 280 nm; column temperature: 30 ℃; injection volume: 20 μL.

[0043] Encapsulation efficiency determination: Ethanol extraction was used. Accurately weigh 0.5 g of sample, add 10 mL of anhydrous ethanol, and extract ultrasonically for 30 minutes (200 W, 25℃). Centrifuge (3000 r / min, 10 minutes), collect the supernatant, and determine the amount of free gingerol on the surface using HPLC. Separately, take another 0.5 g sample, add 10 mL of anhydrous ethanol, heat under reflux for 2 hours, cool, centrifuge, collect the supernatant, and determine the total gingerol content. Encapsulation efficiency = (Total gingerol content - Free gingerol content on the surface) / Total gingerol content × 100%.

[0044] In vitro release rate determination: The dialysis bag method was used. 1.0 g of sample was accurately weighed and placed in a dialysis bag (molecular weight cutoff 1000 Da). 10 mL of deionized water was added, and the bag was sealed and placed in 500 mL of simulated gastric fluid (pH 1.2, containing 0.32% pepsin). The mixture was shaken at 37℃ and 100 rpm for 2 h to release the sample. The dialysis bag was then transferred to 500 mL of simulated intestinal fluid (pH 6.8, containing 1.0% pancreatic enzyme), and the release was continued for 10 h. At 0.5 h, 1 h, 2 h (gastric fluid stage), 4 h, 6 h, 8 h, and 12 h (intestinal fluid stage), 5 mL of the release medium was collected, and 5 mL of the corresponding simulated solution was added. The concentration of gingerol in the release medium was determined by HPLC, and the cumulative release rate was calculated.

[0045] Water vapor transmission rate (WVTR): Referring to GB / T 1037-2021 "Determination of water vapor transmission rate of plastic films and sheets - cup method", a water vapor transmission rate meter was used to measure the amount of water vapor transmitted per unit area per unit time of the coated film under the conditions of temperature 23℃ and relative humidity 50%, and the unit is g / m²·d.

[0046] Mechanical strength testing of the coating film: A universal testing machine was used to prepare 10mm×50mm samples of the coating film. The tensile strength and elongation at break were measured at a tensile speed of 5mm / min. A hardness tester was used to measure the hardness and compressive strength of the coating film.

[0047] Antioxidant indicators in animals: One-day-old white-feathered broilers were randomly divided into 8 groups, with 3 replicates per group and 30 chickens per replicate. They were fed basal feed (blank control), basal feed + Comparative Example 1 product, basal feed + Comparative Example 2 product, basal feed + Comparative Example 3 product, basal feed + Example 1 product, basal feed + Example 2 product, basal feed + Example 3 product, and basal feed + Example 4 product, with each addition at 0.3%. Feeding was continued for 42 days. After the feeding period, 10 chickens were randomly selected from each group, and blood was collected from the wing vein. The blood was centrifuged at 3000 rpm for 10 minutes to separate the serum. The total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px) activities, and malondialdehyde (MDA) content were determined using a kit (purchased from Nanjing Jiancheng Bioengineering Institute), strictly following the kit instructions.

[0048] Palatability evaluation: Record the average daily feed intake of each group of broilers from 1 to 42 days, calculate the difference in feed intake, and evaluate the palatability of the product by combining the flock's feeding behavior, such as feeding speed and whether they refuse to eat.

[0049] Storage stability test: The products of each example and comparative example were sealed and packaged and stored in a high temperature and high humidity environment (40℃, 75%RH) for 30 days. Samples were taken at 0 days, 10 days, 20 days and 30 days to determine the gingerol content and calculate the retention rate. At the same time, the appearance and flowability of the products were observed to evaluate their storage stability.

[0050] Example 1

[0051] Step 1, Preparation of ultrafine ginger powder: Select fresh ginger, wash and slice it, dry it in a 65℃ oven until the moisture content is 4.5%, coarsely grind it, and then pass it through an airflow ultrafine grinder, maintaining a pressure of 0.7MPa for 15 minutes. After sieving, ultrafine ginger powder is obtained, with a particle size distribution of D. 50 =10μm.

[0052] The second step is wall material modification: 2g of chitosan is dissolved in 100mL of 1% acetic acid solution and stirred until completely dissolved to obtain a 2% chitosan solution by mass percentage; 0.06g of KH550 is added, and after stirring evenly, the mixture is reacted in a constant temperature water bath at 50℃ for 3h, with stirring every 30 minutes during the reaction; after the reaction is completed, the mixture is washed 4 times with deionized water until neutral, dried under vacuum at 55℃ to constant weight, and pulverized to obtain silane-grafted modified chitosan powder; the modified chitosan powder is dissolved in deionized water to prepare a 2% modified chitosan solution for later use.

[0053] The third step is core formation: Dissolve 2g of sodium alginate in 100ml of water to prepare a 2% sodium alginate solution. Take 10g of ultrafine ginger powder and disperse it in 20mL of sodium alginate solution. Stir at 1200r / min for 45 minutes to obtain a uniform suspension. Pass the suspension through a dropping device and drop it into 50mL of 2% calcium chloride solution at a rate of 40 drops / min. Let it stand for 1.5 hours to solidify and form cores. After removing the cores, wash them twice with deionized water and drain.

[0054] Step 4, inner coating: Put the ginger powder core into the modified chitosan solution, add 0.5g of sodium tripolyphosphate, let it stand at room temperature for 1 hour to crosslink, forming a hydrophobic and water-blocking layer with a thickness of 0.15mm; after taking it out, wash it once with deionized water and drain the water.

[0055] Step 5, outer coating: Dissolve 2.5g of sodium alginate in 100ml of water to prepare a 2.5% sodium alginate solution. Immerse the particles with the inner coating in the solution and soak for 45 minutes. Add 10mL of 2% calcium chloride solution and let it stand for 30 minutes to solidify, forming a hydrophilic dispersion layer with a thickness of 0.08mm. After removing the particles, wash them once with deionized water and drain.

[0056] Step 6, drying and collection: Dry in a 55℃ oven until the moisture content is 4%, sieve to obtain the final product with a particle size of about 1.2mm, and seal and package for later use.

[0057] Results: The product encapsulation rate was 82%, the water vapor permeability of the coating film was 6.8 g / m²·d, and the compressive strength was 18 N; the release rate of simulated gastric juice in 2 hours was 12%, and the cumulative release rate of simulated intestinal juice in 12 hours was 68%; after 30 days of high temperature and high humidity storage, the gingerol retention rate was 89%, the product showed no moisture absorption or clumping, and good flowability; in animal feeding trials, the average daily feed intake of broilers increased by 3.2% compared with the blank control group, the final weight was 2030 g, the feed conversion ratio was 1.52, the serum T-SOD activity was 150 U / mL, the GSH-Px activity was 300 U / mL, and the MDA content was 1.20 nmol / mL, showing significant antioxidant effects and good palatability.

[0058] Example 2

[0059] Same as Example 1, except that: in the second step, the amount of KH550 added is 0.1g, the reaction temperature is 55℃, and the reaction time is 3.5h.

[0060] Results: The product encapsulation rate was 80%, the water vapor permeability of the coating film was 5.8 g / m²·d, which was 15% lower than that of Example 1, and the compressive strength was 20 N, which was 11% higher than that of Example 1; the release rate of simulated gastric juice in 2 hours was 10%, and the cumulative release rate of simulated intestinal juice in 12 hours was 66%; after 30 days of high temperature and high humidity storage, the gingerol retention rate was 91%, which was 2% higher than that of Example 1, and the storage stability was slightly better; in the animal feeding test, the broiler chickens had a final weight of 2010 g, a feed conversion ratio of 1.53, serum T-SOD activity of 148 U / mL, GSH-Px activity of 295 U / mL, and MDA content of 1.25 nmol / mL. The antioxidant effect was similar to that of Example 1, and the palatability was good.

[0061] Example 3

[0062] Same as Example 1, except that: in the first step, the ginger powder is coarsely ground, D 50 =160μm, without airflow ultrafine grinding.

[0063] Results: The product encapsulation rate was 75%, the water vapor permeability of the coating film was 7.0 g / m²·d, and the compressive strength was 17 N. The release rate of simulated gastric juice in 2 hours was 15.2%, and the cumulative release rate of simulated intestinal juice in 12 hours was 58.4%, which was 14% lower than that of Example 1. The in vitro release rate was significantly slower than that of Example 1. After 30 days of high temperature and high humidity storage, the gingerol retention rate was 87%. In animal feeding trials, the average daily feed intake of broilers was 2.5% lower than that of Example 1, the final weight was 1920 g, the feed conversion ratio was 1.58, the serum T-SOD activity was 135 U / mL, the GSH-Px activity was 260 U / mL, and the MDA content was 1.45 nmol / mL. The antioxidant effect was poor, mainly because the ginger powder particle size was too large, the dissolution rate of active ingredients was slow, and the bioavailability was insufficient.

[0064] Example 4

[0065] Same as Example 1, except that in the third step, 0.3g of glycerol is added as a plasticizer to the ginger powder-sodium alginate suspension, accounting for 3% of the weight of ginger powder, and the mixture is stirred evenly before pelleting.

[0066] Results: The product encapsulation rate was 83%, the water vapor permeability of the coating film was 6.7 g / m²·d, the compressive strength was 19 N, and the elongation at break was 15% higher than that of Example 1, with better coating film flexibility; the release rate of simulated gastric juice in 2 hours was 11.8%, and the cumulative release rate of simulated intestinal juice in 12 hours was 69%; after 30 days of high temperature and high humidity storage, the gingerol retention rate was 90%, and the product showed no cracking or damage; in animal feeding trials, with a broiler weight of 2040 g, a feed conversion ratio of 1.51, serum T-SOD activity was 152 U / mL, GSH-Px activity was 305 U / mL, and MDA content was 1.18 nmol / mL, showing slightly better antioxidant effect and palatability than Example 1.

[0067] Comparative Example 1 The 1000-mesh ultrafine ginger powder prepared in Example 1 was used directly without any coating treatment as Comparative Example 1.

[0068] Results: No encapsulation rate; 85.2% release rate in simulated gastric juice over 2 hours, indicating severe burst release, with active ingredients being released and degraded in large quantities in the stomach; after 30 days of high temperature and humidity storage, gingerol loss was 45%, with a retention rate of only 55%, and the product exhibited severe moisture absorption and clumping; in animal feeding trials, due to the pungent taste, broilers experienced an 8.3% decrease in average daily feed intake compared to Example 1, with a final weight of 1950g, a feed conversion ratio of 1.62, serum T-SOD activity of 130U / mL, GSH-Px activity of 250U / mL, and MDA content of 1.80 nmol / mL, showing the worst antioxidant effect.

[0069] Comparative Example 2 Same as Example 1, except that the inner coating in step four is omitted, and only the outer sodium alginate coating in step five is retained, i.e., a single-layer coating structure.

[0070] Results: The product encapsulation rate was 78%, the water vapor permeability of the coating film was 15.2 g / m²·d, the compressive strength was 8 N, the mechanical strength was low, and it was easily broken in simulated gastric juice; the release rate of simulated gastric juice in 2 hours was 45.6%, the acid resistance was poor, and the active ingredients were released prematurely; after 30 days of high temperature and high humidity storage, the gingerol retention rate was 68%; in the animal feeding test, the broiler weight was 1980 g, the feed conversion ratio was 1.58, the serum T-SOD activity was 140 U / mL, the GSH-Px activity was 270 U / mL, and the MDA content was 1.50 nmol / mL. The antioxidant effect and storage stability were significantly worse than those in Example 1.

[0071] Comparative Example 3 Same as Example 1, except that KH550 is not added in the second step, and unmodified ordinary chitosan is used to prepare the inner coating, while the other steps remain unchanged.

[0072] Results: The product encapsulation rate was 79%, the water vapor permeability of the coating film was 12.5 g / m²·d (50% higher than Example 1), and the compressive strength was 10 N; the release rate of simulated gastric juice in 2 hours was 18.5%, and the cumulative release rate of intestinal juice in 12 hours was 65.2%; after 30 days of high temperature and high humidity storage, the gingerol retention rate was 72% (20% lower than Example 1); in animal feeding trials, the broiler weight was 1960 g, the feed conversion ratio was 1.60, the serum T-SOD activity was 138 U / mL, the GSH-Px activity was 265 U / mL, and the MDA content was 1.55 nmol / mL. The antioxidant effect and storage stability were worse than those of Example 1, proving that silane modification plays a key role in improving the performance of the wall material.

[0073] The results are shown in Tables 1 to 3.

[0074] Table 1. Comparison of in vitro release performance of different embodiments and comparative examples Group <![CDATA[Ginger powder particle size (D 50 )]]> Coating structure Gastric juice release rate (2h, %) Cumulative release rate of intestinal fluid (12h, %) Release mechanism Compressive strength (N) of coating film Comparative Example 1 10μm none 85.2 92.5 Rapid dissolution, severe burst release - Comparative Example 2 10μm Monolayer (sodium alginate) 45.6 75.3 Partial protection, poor acid resistance 8 Comparative Example 3 10μm Double-layered (unmodified chitosan + sodium alginate) 18.5 65.2 Slow-release, poor water-blocking effect 10 Example 3 160μm Double-layer (modified chitosan + sodium alginate) 15.2 58.4 Slow-release, slow dissolution rate 17 Example 1 10μm Double-layer (modified chitosan + sodium alginate) 12.1 68.5 Targeted sustained release, gastrointestinal-protected release 18 Example 2 10μm Double-layer (modified chitosan + sodium alginate) 10.0 66.0 Targeted sustained release for superior water-blocking effect 20 Table 1 shows that the double-layer modified coating structures of Examples 1 and 2 of the present invention can significantly reduce the release rate of the active ingredient in gastric juice, from 85.2% in the uncoated control group (Comparative Example 1) to 10.0%–12.1%, effectively achieving a "gastric avoidance" effect and preventing the active ingredient from being released and degraded prematurely in the stomach. The gastric juice release rates of the single-layer coated control group (Comparative Example 2) and the unmodified double-layer coated control group (Comparative Example 3) are significantly higher than those of the present invention, making it difficult to achieve effective gastric acid protection. Comparing Examples 1 and 3, it is evident that the formulation using ultrafine ginger powder has a higher cumulative intestinal release rate, indicating that ultrafine pulverization can break the plant cell wall barrier, promote the dissolution of active ingredients, and improve bioavailability. Furthermore, the compressive strength of the coating films in Examples 1 and 2 is significantly better than that in Comparative Examples 2 and 3, indicating that silane modification can effectively improve the mechanical strength of the coating film and reduce damage to the formulation during processing.

[0075] Table 2. Comparison of storage stability of different embodiments and comparative examples (40℃, 75% RH, 30 days) Group Initial gingerol content (mg / g) Content (mg / g) after 30 days Retention rate (%) Water vapor transmission rate (g / m²·d) Appearance Comparative Example 1 5.20 2.86 55.0 - It absorbs moisture severely, clumps together, and darkens in color. Comparative Example 2 5.17 3.51 68.0 15.2 Slightly absorbed moisture; some particles were damaged. Comparative Example 3 5.15 3.71 72.0 12.5 Slightly absorbs moisture, granules remain intact. Example 1 5.18 4.61 89.0 6.8 It does not absorb moisture, does not clump, and has good flowability. Example 2 5.21 4.74 91.0 5.8 It does not absorb moisture, does not clump, and has good flowability. Table 2 shows that silane modification is a key factor in significantly improving the storage stability of the product of this invention. Compared with Comparative Example 3 (unmodified chitosan coating group), the water vapor permeability of the coating films in Examples 1 and 2 of this invention significantly decreased from 12.5 g / m²·d to 5.8–6.8 g / m²·d, effectively blocking the intrusion of moisture and oxygen, and increasing the storage retention rate of gingerol from 72% to 89%–91%. Comparative Example 1 (uncoated group) and Comparative Example 2 (single-layer coating group) showed poor storage stability, with significant loss of gingerol, and the products were prone to moisture absorption and clumping, making it difficult to meet the requirements for long-term storage. After 30 days of storage under high temperature and high humidity conditions, the product of this invention showed good appearance and no significant impact on particle flowability, further confirming its excellent storage stability.

[0076] Table 3 Results of animal feeding trials Group Final weight (g) Meat-to-fat ratio Average daily feed intake (g / animal) T-SOD (U / mL) GSH-Px (U / mL) MDA (nmol / mL) Palatability evaluation Blank control 1960 1.58 58.2 125 240 1.90 Normal, no refusal to eat Comparative Example 1 1950 1.62 54.8 130 250 1.80 Poor quality, some children refuse to eat. Comparative Example 2 1980 1.58 57.5 140 270 1.50 Good, no food refusal Comparative Example 3 1960 1.60 57.2 138 265 1.55 Good, no food refusal Example 3 1920 1.58 56.5 135 260 1.45 Good, no food refusal Example 1 2030 1.52 60.1 150 300 1.20 Excellent, actively foraging Example 2 2010 1.53 59.8 148 295 1.25 Excellent, actively foraging Example 4 2040 1.51 60.5 152 305 1.18 Excellent, most active in foraging As shown in Table 3, the blank control group had a final weight of 1960g, a feed conversion ratio of 1.58, and an average daily feed intake of 58.2g / bird. The growth performance of each comparative product group did not reach the level of the embodiments of this invention: Comparative Example 1 (uncoated) had the lowest average daily feed intake (only 54.8g / bird) due to its pungent taste, a final weight of 1950g, and a feed conversion ratio of 1.62, resulting in the worst growth performance; Comparative Example 2 (single-layer coating) and Comparative Example 3 (unmodified chitosan double-layer coating) had final weights of 1980g and 1960g respectively, feed conversion ratios of 1.58–1.60, and average daily feed intakes of 57.2–57.5g / bird, showing slightly better results than the blank control, but with limited improvement; Example 3 (ordinary particle size ginger powder double-layer coating) had a final weight of 1920g and a feed conversion ratio of 1.58. Due to the larger particle size of the ginger powder and insufficient dissolution of active ingredients, its growth performance was slightly lower than the blank control group.

[0077] The growth performance of Examples 1, 2, and 4 of this invention is significantly better than that of the control groups and comparative examples: Example 4 (with added plasticizer) had the highest final weight of 2040g, the lowest feed conversion ratio of 1.51, and the highest average daily feed intake of 60.5g / bird; Example 1 (preferred example) had a final weight of 2030g, a feed conversion ratio of 1.52, and an average daily feed intake of 60.1g / bird; Example 2 (silane-modified and optimized) had a final weight of 2010g, a feed conversion ratio of 1.53, and an average daily feed intake of 59.8g / bird. The final weight of all three examples was 3.6%–4.1% higher than the blank control, the feed conversion ratio was 3.8%–4.4% lower, and the average daily feed intake was 3.3%–3.9% higher, fully demonstrating that the product of this invention can effectively improve the growth performance of broilers and increase feed utilization. This is mainly due to the high bioavailability of the ultrafine ginger powder and the targeted sustained-release effect of the double-layer coating, which allows active ingredients such as gingerol to be continuously and efficiently absorbed by the animals, thereby promoting growth.

[0078] Serum total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) activities, as well as malondialdehyde (MDA) content, are important indicators for evaluating the antioxidant status of animals. Higher T-SOD and GSH-Px activities indicate a stronger ability to scavenge free radicals and inhibit lipid peroxidation. MDA, a product of lipid peroxidation, is less severe in terms of its content, indicating less oxidative damage. In the blank control group, T-SOD activity was 125 U / mL, GSH-Px activity was 240 U / mL, and MDA content was 1.90 nmol / mL, indicating that broilers under normal feeding conditions experienced a certain degree of oxidative stress. Comparative Example 1 (uncoated) showed only slightly better antioxidant performance than the blank control group, with T-SOD and GSH-Px activities of 130 U / mL and 250 U / mL, respectively, and MDA content of 1.80 nmol / mL. This was mainly due to the rapid release and degradation of gingerol in the stomach, making it difficult to fully exert its antioxidant effect. Comparative Examples 2 and 3 showed improved antioxidant performance, with T-SOD activity of 138–140 U / mL, GSH-Px activity of 265–270 U / mL, and MDA content of 1.50–1.55 nmol / mL. However, due to limitations in coating performance, the release and retention of active ingredients were limited, resulting in a low increase in antioxidant activity. Example 3 (ordinary particle size ginger powder) showed a T-SOD activity of 135 U / mL and a GSH-Px content of 1.80 nmol / mL. The activity was 260 U / mL, and the MDA content was 1.45 nmol / mL. These indicators were slightly better than the comparative example, but lower than other embodiments of the present invention, further confirming the important role of ultrafine grinding in improving the bioavailability of active ingredients and enhancing the body's antioxidant capacity.

[0079] The antioxidant indicators of the products in this invention are outstanding: In Example 4, the T-SOD activity reached 152 U / mL, and the GSH-Px activity reached 305 U / mL, representing increases of 21.6% and 27.1% respectively compared to the blank control, while the MDA content decreased to 1.18 nmol / mL, a reduction of 37.9% compared to the blank control; in Example 1, the T-SOD activity was 150 U / mL, and the GSH-Px activity was 300 U / mL, representing increases of 20.0% and 25.0% respectively compared to the blank control, while the MDA content was 1.20 nmol / mL, a reduction of 36.8%; the antioxidant indicators of Example 2 were similar to those of Example 1, with a T-SOD activity of 148 U / mL, a GSH-Px activity of 295 U / mL, and an MDA content of 1.25 nmol / mL. These results fully demonstrate that the products of this invention can significantly enhance the antioxidant capacity of broilers, effectively alleviate oxidative stress, and are significantly superior to uncoated, single-layer coated, and unmodified chitosan-coated products. Its core mechanism lies in the synergistic effect of ultrafine grinding and silane-modified double-layer coating, which enables the targeted release and efficient absorption of active ingredients such as gingerol in the intestine, giving full play to their antioxidant function.

[0080] Palatability directly affects animal feed intake, and consequently, growth performance. Comparative Example 1 (uncoated) was not coated, and the pungent flavor of ginger was not masked, resulting in some broilers refusing to eat, with the lowest average daily feed intake and poor palatability. The blank control group, the other comparative examples, and the groups in each embodiment of this invention showed no refusal to eat. Specifically, the broilers in Examples 1, 2, and 4 of this invention exhibited active feeding, with significantly higher average daily feed intake than other groups, and their palatability was rated as excellent. Examples 3, Comparative Example 2, and 3 showed normal feeding behavior, and their palatability was rated as good. This is because the double-layer coating structure used in this invention effectively masks the pungent flavor of ginger, while the fine texture of the ultrafine ginger powder further reduces the pungent irritation, significantly improving product palatability and providing an important guarantee for increasing animal feed intake and promoting growth and development.

[0081] All of the foregoing primary implementations of this intellectual property right do not limit other forms of implementation of this new product and / or new method. Those skilled in the art will utilize this important information to modify the foregoing to achieve similar implementations. However, all modifications or alterations based on this new product invention are reserved rights.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A two-layer slow-release feed antioxidant based on ultrafine ginger powder, characterized in that: It consists of a core particle and a double-layer coating; the core particle is ultrafine ginger powder; the double-layer coating consists of a hydrophobic and water-blocking layer formed by solidification of silane-grafted modified chitosan and a hydrophilic dispersion layer formed by solidification of sodium alginate from the inside out; the crosslinking agent used for solidification is sodium tripolyphosphate or calcium chloride.

2. The antioxidant according to claim 1, characterized in that: The particle size distribution of the ultrafine ginger powder is: D 50 =5~15μm.

3. The antioxidant according to claim 1 or 2, characterized in that: The silane-grafted modified chitosan is prepared by reacting chitosan with a silane coupling agent in an acetic acid solution; the silane coupling agent is γ-aminopropyltriethoxysilane or γ-epoxypropoxypropyltrimethoxysilane, and the amount added is 1 to 5% of the mass of chitosan.

4. The antioxidant according to claim 1 or 2, characterized in that: Based on 100 parts by weight of ultrafine ginger powder, the modified chitosan content in the hydrophobic and water-blocking layer is 15-25 parts, the sodium alginate content in the hydrophilic dispersion layer is 20-30 parts, and the total crosslinking agent content is 0.5-2 parts.

5. The antioxidant according to claim 1 or 2, characterized in that: It also contains a plasticizer, which is propylene glycol or glycerin, used in an amount of 1 to 5% of the weight of the ultrafine ginger powder.

6. A method for preparing a double-layer slow-release feed antioxidant based on ultrafine ginger powder as described in any one of claims 1 to 5, characterized in that: Includes the following steps: (1) Preparation of ultrafine ginger powder: Wash and slice fresh ginger, dry it until the moisture content is ≤5%, and coarsely grind it to D. 50 =125~250 μm, then subjected to airflow ultrafine pulverization to D 50 =5~15 μm; (2) Wall material modification: Chitosan is dissolved in acetic acid solution, and silane coupling agent is added and reacted at 40-60℃ for 2-4 hours to obtain silane grafted modified chitosan solution; (3) Core formation: Ultrafine ginger powder is dispersed in sodium alginate solution, and calcium chloride solution is added dropwise to cross-link and solidify, thus obtaining ginger powder core; (4) Inner coating: The pellet core is placed in a modified chitosan solution and cross-linked and cured with sodium tripolyphosphate to form a hydrophobic and water-blocking layer; (5) Outer coating: The inner coating particles are immersed in sodium alginate solution and cross-linked and solidified again to form a hydrophilic dispersion layer; (6) Drying and collection: Dry at 50-60℃ until the moisture content is <5%, and then sieve to obtain the finished product.

7. The preparation method according to claim 6, characterized in that, In step (2), the acetic acid solution has a mass percentage concentration of 1%, and the chitosan solution has a mass percentage concentration of 1-3%.

8. The preparation method according to claim 6 or 7, characterized in that, In step (3), the mass percentage concentration of calcium chloride solution is 1-5%, the cross-linking curing time is 1-2 hours, and the core particle size is controlled at 0.8-1.2 mm.

9. The preparation method according to claim 6 or 7, characterized in that, In step (4), the amount of sodium tripolyphosphate used is 5-10% of the mass of modified chitosan, and the cross-linking time is 1-2 hours.

10. The use of the antioxidant according to any one of claims 1 to 5 in the preparation of livestock or aquatic feed that improves the antioxidant capacity, growth performance and palatability of animals.