Natural spice feed additive for improving pork quality and preparation method thereof

Abstract

The application belongs to the technical field of Chinese herbal medicine feed additives, and particularly discloses a natural spice feed additive for improving pork quality and a preparation method thereof, which is made of natural raw materials and modified porous starch-pectin compound; the natural raw materials include antioxidant components, antioxidant components and spleen-strengthening and absorption-promoting components; the antioxidant components include eucommia leaf, astragalus root, mulberry leaf and rosemary; the antioxidant components include thyme, clove, cinnamon, dried ginger, Sichuan pepper, star anise and dried tangerine or orange peel; and the spleen-strengthening and absorption-promoting components include radix codonopsis, licorice, angelica, Sichuan lovage rhizome, Chinese yam, malt, hawthorn, tuckahoe, Chinese yam and lotus seed. The antioxidant components, flavor components and spleen-strengthening and absorption-promoting components are used as natural functional cores, and the modified porous starch-pectin compound is used as a slow-release carrier, so that the pork quality is improved from multiple aspects such as pig intestinal tract absorption, in-vivo metabolism, muscle cell structure, lipid oxidation inhibition and flavor precursor deposition.

Description

Technical Field

[0001] This application relates to the field of traditional Chinese medicine feed additives, specifically a natural spice feed additive for improving pork quality and its preparation method. Background Technology

[0002] As the level of large-scale pig farming continues to improve, the market has placed higher demands on the quality, flavor, freshness, and safety of pork. In actual farming, pigs are prone to oxidative stress, low digestive and absorption efficiency, and uneven muscle fat deposition in the later stages of fattening. This results in high drip loss, insufficient tenderness, and bland flavor in the pork after slaughter. At the same time, lipid oxidation is prone to occur during storage and distribution, shortening shelf life and affecting commercial value.

[0003] Currently, feed additives used to improve pork quality are mostly antioxidants, vitamins, or minerals, which suffer from problems such as limited functionality, limited effects, and insufficient stability. Meanwhile, traditional additive preparation processes often involve simple grinding and mixing, resulting in uneven component dispersion and low absorption and utilization rates. These methods fail to fundamentally improve muscle cell structure and metabolic levels, making it difficult to achieve a synergistic improvement in water retention, tenderization, antioxidant properties, and flavor enhancement.

[0004] Furthermore, most feed additives on the market rely on chemically synthesized ingredients, posing a risk of residue with long-term use, and do not meet consumers' demand for green, natural, and antibiotic-free livestock products. While natural spices and medicinal plants possess potential for anti-oxidation, spleen-strengthening, and digestion-promoting effects, direct addition presents challenges such as poor palatability, slow release, and unstable efficacy. Moreover, the lack of efficient carriers and modification processes makes it difficult to fully leverage the advantages of natural raw materials.

[0005] Therefore, developing a feed additive that uses natural raw materials as its core, has a scientific formulation, stable processing technology, and can comprehensively improve pork quality has become an urgent need in the field of healthy pig farming and meat quality improvement. Summary of the Invention

[0006] In view of this, the purpose of this invention is to overcome the shortcomings of the prior art by proposing a natural spice feed additive for improving pork quality and its preparation method, so as to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides a natural spice feed additive for improving pork quality, which is made from the following natural raw materials in parts by weight, and a modified porous starch-pectin complex accounting for 5% to 10% of the total weight of all natural raw materials. The natural ingredients include: antioxidant components and spleen-strengthening and absorption-promoting components; The antioxidant components include: 15-25 parts of Eucommia ulmoides leaves, 10-20 parts of Astragalus membranaceus, 10-18 parts of mulberry leaves, and 4-9 parts of rosemary; The antioxidant components include: 5-10 parts thyme, 3-8 parts cloves, 5-10 parts cinnamon, 4-8 parts dried ginger, 3-6 parts Sichuan pepper, 3-7 parts star anise, and 5-10 parts dried tangerine peel; The spleen-strengthening and absorption-promoting components include: 8-15 parts of Codonopsis pilosula, 6-12 parts of Glycyrrhiza uralensis, 2-5 parts of Angelica sinensis, 2-4 parts of Ligusticum chuanxiong, 4-8 parts of Massa fermentata, 5-9 parts of Hordeum vulgare, 6-12 parts of Crataegus pinnatifida, 4-8 parts of Poria cocos, 5-10 parts of Dioscorea opposita, and 3-7 parts of Nelumbo nucifera.

[0008] As a further technical solution, the modified porous starch-pectin complex is prepared by a method comprising the following steps: S1. Preparation of porous starch: Food-grade waxy corn starch was selected and a starch-deionized water suspension with a mass concentration of 30% was prepared. After stirring and dissolving at room temperature, the pH of the suspension was adjusted to 8.5, and a complex enzyme system composed of α-amylase and saccharifying enzyme was added. The total amount of enzyme added was 0.3 wt% of the dry weight of starch. The system was kept at 55℃ and 80 r / min for constant temperature stirring and enzymatic hydrolysis for 4 h. After the enzymatic hydrolysis was completed, the enzyme was inactivated by heating in a 95℃ water bath for 10 min, cooled to room temperature, and the material was repeatedly washed with deionized water until the filtrate was neutral. The material was dried, pulverized, and passed through a 60-mesh sieve to obtain porous starch powder. S2. Preparation of pectin gel microspheres: Food-grade citrus pectin was selected and dissolved in room temperature deionized water to prepare a 2.0% (w / w) pectin aqueous solution. The solution was continuously stirred until completely dissolved and no colloidal agglomeration occurred. 0.5 mol / L calcium chloride aqueous solution was added dropwise at a rate of 15%–20% of the volume of the pectin aqueous solution. Ionic crosslinking was carried out for 1.5 h under constant temperature stirring at 50 r / min to form uniform pectin gel microspheres in situ. The gel microspheres were freeze-dried at -40℃ for 12 h. After drying, the microspheres were pulverized and sieved to select powder with a particle size of 10–50 μm to obtain pectin microspheres. S3. Weak acid covalent grafting modification: The porous starch obtained in step S1 and the pectin microspheres obtained in step S2 are mixed evenly at a mass ratio of 3:1 to obtain a composite powder. Based on the total mass of the composite powder, 2wt% oligomannose and 0.8wt% sodium glycerophosphate are added respectively, and the mixture is stirred continuously for 20 minutes to ensure uniform mixing. Dilute citric acid solution is added dropwise to adjust the pH of the system to be stable at 5.5-6.0. The mixed powder is put into a fluidized bed device and subjected to solid-phase composite reaction for 2 hours under the conditions of 45℃, 75% relative humidity, high-purity nitrogen gas sealing protection, and fluidized bed wind speed of 0.8m / s. The reaction is carried out in the dark throughout. After the reaction, the powder is collected and dried with hot air until the powder moisture content is ≤5wt% to obtain the modified porous starch-pectin microsphere composite.

[0009] As a further technical solution, the enzyme activity ratio of α-amylase to saccharifying enzyme in the complex enzyme system is 2:1.

[0010] As a further technical solution, the feed additive is applied to pigs starting to be fed 2 months before slaughter or starting to be fed from 60 kg until slaughter, at a rate of 1-2% of the daily feed amount, for 2 consecutive months.

[0011] A method for preparing a natural spice feed additive to improve pork quality includes the following steps: P1. Raw material pretreatment and aerobic fermentation: The antioxidant components, flavor precursor components, and spleen-strengthening and absorption-promoting components are pulverized to 40 mesh and mixed evenly. The mixture is moistened for 2 hours in a sealed, sterile environment at room temperature. Lactobacillus plantarum with a viable count of ≥95% and Saccharomyces cerevisiae are selected and mixed at a viable count ratio of 1:0.5 to obtain a mixed bacterial solution. After activation at 30℃ for 30 minutes, the solution is inoculated at 3% to 5% of the total mass of the raw materials and aerobic fermented at 32℃ for 24 hours. P2. Gradient temperature-controlled anaerobic fermentation: The material after aerobic fermentation is transferred to an anaerobic environment with an oxygen content of ≤1% and continuous sterile carbon dioxide flow at normal pressure. The relative humidity of the anaerobic environment is 60%~65%, and the temperature control error is ±0.5℃. Gradient cooling fermentation is adopted, and the total anaerobic fermentation time is 48h. After the fermentation product is filtered through a 40-mesh sieve to remove impurities, it is dried at 50℃ using hot air circulation at a wind speed of 1.2m / s to obtain fermented dry powder. P3. Ultrasonic Coupling Modification and Finished Product Refining: The fermented dry powder and the modified porous starch-pectin complex are mixed evenly. Under sealed, sterile, light-proof conditions and an ambient temperature of 25°C, pulsed ultrasound is used for 15 minutes as an auxiliary treatment. After ultrasonic treatment, the mixture is allowed to stand and mature for 30 minutes. Then, it is ultra-finely pulverized at 3000 r / min airflow to a material D90 particle size of 15-25 μm. The material moisture content is controlled to ≤8 wt%. The mixture is vacuum-packed under ambient humidity ≤40% to obtain the finished feed additive.

[0012] As a further technical solution, in step P1, the ambient temperature for lubrication is 20-25℃ and the ambient humidity is 45%-55%. The entire process is carried out in a dark, sterile, and sealed environment for 2 hours for lubrication.

[0013] As a further technical solution, in step P2, gradient cooling fermentation is adopted: fermentation at 30℃ for 12 hours, fermentation at 26℃ for 18 hours, fermentation at 22℃ for 18 hours, with a total anaerobic fermentation time of 48 hours.

[0014] As a further technical solution, in step P3, the frequency of the pulse ultrasound is 20kHz, the power is 300W, and the pulse duty cycle is 1:1.

[0015] As a further technical solution, after vacuum packaging, a low-dose irradiation treatment of 3kGy is used for antibacterial treatment, and the finished product can be kept at room temperature for more than 12 months.

[0016] The natural spice feed additive of this invention, which improves pork quality, can also be applied to improve the quality of other livestock and poultry meat.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention uses antioxidant components, flavor components, and spleen-strengthening and absorption-promoting components as natural functional cores, combined with modified porous starch-pectin complex as a slow-release carrier, and is prepared through a combination of aerobic fermentation, gradient anaerobic fermentation, and ultrasonic-coupled ultrafine grinding processes. The components and steps form a progressive and synergistic effect, which improves pork quality from multiple levels, including intestinal absorption, in vivo metabolism, muscle cell structure, lipid oxidation inhibition, and flavor precursor deposition in pigs.

[0018] Because this invention uses a compound of Eucommia ulmoides leaves, Astragalus membranaceus, mulberry leaves, and rosemary to form an antioxidant component, Eucommia ulmoides leaves and Astragalus membranaceus are rich in flavonoids and polysaccharides, which can significantly increase the activity of antioxidant enzymes such as superoxide dismutase and glutathione peroxidase in pigs. Deoxynojirimycin in mulberry leaves and caryophylloxin and rosmarinic acid in rosemary can directly scavenge oxygen free radicals and reactive oxygen species, thereby stabilizing muscle cell membrane structure, inhibiting myofibril membrane damage and intracellular water outflow, and blocking the auto-oxidation chain reaction of unsaturated fatty acids such as linoleic acid and arachidonic acid in muscles, reducing the lipid oxidation rate at the cellular level, thus solving the technical problems of high drip loss, high MDA content, and rapid flavor deterioration during pork refrigeration. Meanwhile, the volatile oils, phenols, and aldehydes in flavor components such as thyme, cloves, cinnamon, dried ginger, Sichuan pepper, star anise, and dried tangerine peel can be absorbed by the intestines and specifically deposited in muscle tissue. They participate in the synthesis and transformation of flavor precursors in muscle, increase the content of branched-chain fatty acids, aldehydes, and esters in intramuscular fat, and thus give pork a natural and mellow aroma, solving the problem of bland flavor and monotonous taste in pork from large-scale farms.

[0019] This invention incorporates a combination of Codonopsis pilosula, licorice, Angelica sinensis, Ligusticum chuanxiong, medicated leaven, malt, hawthorn, Poria cocos, Dioscorea opposita, and lotus seed to form a spleen-strengthening and absorption-promoting component. Hawthorn, medicated leaven, and malt can increase the activity of amylase, lipase, and protease in the pig's intestines, promoting the digestibility and absorption of protein, energy, and minerals in the diet. Poria cocos, Dioscorea opposita, and lotus seed can regulate the intestinal flora structure, repair the intestinal mucosal barrier, and reduce intestinal inflammation and oxidative stress levels. Codonopsis pilosula, Angelica sinensis, and Ligusticum chuanxiong can improve blood circulation and nutrient delivery efficiency, promote uniform muscle fiber development and moderate intramuscular fat deposition, resulting in finer muscle fibers and more even intramuscular fat distribution. This histologically enhances the tenderness and juiciness of pork, thus addressing the problems of high shear strength, tough texture, and poor chewiness in pork. When these three types of natural components are combined in specific weight proportions, their antioxidant, flavor-enhancing, and absorption-promoting functions complement each other, achieving a synergistic effect of "in vivo antioxidant activity, high intestinal absorption, and optimized muscle structure," avoiding the limitations of single-function additives.

[0020] This invention further amplifies the efficacy of natural components through a modified porous starch-pectin complex combined with a stepped fermentation and ultrasonic coupling process, forming a complete synergistic mechanism. First, the modified porous starch-pectin complex uses waxy corn starch enzymatically hydrolyzed to form a porous structure, and citrus pectin ionically cross-linked to form microspheres. This is then combined through solid-phase grafting in a weakly acidic environment, resulting in a high specific surface area, high loading capacity, and pH-responsive slow-release properties. This allows for the adsorption and encapsulation of natural active substances, preventing their inactivation and decomposition during processing, storage, and in the acidic environment of the stomach. This enables the slow, continuous, and stable release of active ingredients in the pig's intestines, significantly improving bioavailability. Second, aerobic fermentation of the raw materials degrades crude fiber and macromolecular polysaccharides, improving component solubility and palatability. Gradient temperature-controlled anaerobic fermentation protects heat-sensitive active substances at low temperatures and allows for full biotransformation at medium temperatures, increasing the solubility of active ingredients. Pulsed ultrasonic coupling disrupts plant cell walls, allowing for the full release of effective components. Simultaneously, it ensures uniform dispersion of the complex and fermented powder, resulting in finer particle size, larger contact area, and faster absorption after ultrafine pulverization. Ultimately, this invention achieves a comprehensive effect of low drip loss, high tenderness, strong antioxidant properties, rich flavor, and safety with no residue through the combined action of three mechanisms: raw material compatibility, carrier protection, and process enhancement. It comprehensively solves the industry problems of poor stability, low utilization rate, single function, and unstable effect of existing natural additives, and is suitable for long-term use in large-scale breeding. Detailed Implementation

[0021] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to specific examples. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] This invention provides a natural spice feed additive for improving pork quality, made from natural raw materials and a modified porous starch-pectin complex. The natural raw materials include antioxidant components, flavor components, and spleen-strengthening and absorption-promoting components. The modified porous starch-pectin complex is prepared by specific enzymatic hydrolysis, cross-linking, and solid-phase composite reaction. The feed additive is prepared by pretreatment fermentation, gradient anaerobic fermentation, and ultrasonic coupling modification. When applied to pig feed, it can effectively improve pork quality.

[0023] This invention first prepares a modified porous starch-pectin complex, the specific steps of which are as follows: S1. Preparation of porous starch: Food-grade waxy corn starch was selected and prepared into a 30% (w / w) starch-deionized water suspension. After dissolving by stirring at room temperature, the pH of the suspension was adjusted to 8.5. A complex enzyme system consisting of α-amylase and saccharifying enzyme was added, with a total enzyme addition of 0.3 wt% of the dry weight of the starch. The system was maintained at a constant temperature of 55℃ and 80 r / min for 4 hours for enzymatic hydrolysis. After enzymatic hydrolysis, the enzyme was inactivated by heating in a 95℃ water bath for 10 minutes. After cooling to room temperature, the material was repeatedly washed with deionized water until the filtrate was neutral. The material was then dried, pulverized, and passed through a 60-mesh sieve to obtain porous starch powder. The optimal enzyme activity ratio of α-amylase to saccharifying enzyme in the complex enzyme system was 2:1.

[0024] S2. Preparation of pectin gel microspheres: Food-grade citrus pectin was selected and dissolved in room temperature deionized water to prepare a 2.0% (w / w) pectin aqueous solution. The solution was continuously stirred until completely dissolved and no colloidal agglomeration occurred. 0.5 mol / L calcium chloride aqueous solution was added dropwise at a rate of 15%–20% of the volume of the pectin aqueous solution. Ionic crosslinking was carried out for 1.5 h under constant temperature stirring at 50 r / min to form uniform pectin gel microspheres in situ. The gel microspheres were freeze-dried at -40℃ for 12 h. After drying, the microspheres were pulverized and sieved to select powder with a particle size of 10–50 μm to obtain pectin microspheres.

[0025] S3. Weak acid covalent grafting modification: The porous starch obtained in step S1 and the pectin microspheres obtained in step S2 were mixed evenly at a mass ratio of 3:1 to obtain a composite powder. Based on the total mass of the composite powder, 2 wt% oligomannose and 0.8 wt% sodium glycerophosphate were added respectively, and the mixture was stirred continuously for 20 min to ensure uniform mixing. Dilute citric acid solution was added dropwise to adjust the pH of the system to be stable at 5.5-6.0. The mixed powder was put into a fluidized bed device and subjected to solid-phase composite reaction for 2 h under the conditions of 45℃, 75% relative humidity, high-purity nitrogen gas sealing protection, and fluidized bed wind speed of 0.8 m / s. The reaction was carried out in the dark throughout. After the reaction, the powder was collected and dried with hot air until the moisture content of the powder was ≤5 wt% to obtain the modified porous starch-pectin microsphere composite.

[0026] The natural raw materials in this invention include antioxidant components, flavor components, and spleen-strengthening and absorption-promoting components.

[0027] The preferred antioxidant components include 15-25 parts of Eucommia ulmoides leaf, 10-20 parts of Astragalus membranaceus, 10-18 parts of mulberry leaf, and 4-9 parts of rosemary.

[0028] The preferred flavor components include 5-10 parts thyme, 3-8 parts cloves, 5-10 parts cinnamon, 4-8 parts dried ginger, 3-6 parts Sichuan pepper, 3-7 parts star anise, and 5-10 parts dried tangerine peel.

[0029] The preferred components for strengthening the spleen and promoting absorption include 8-15 parts of Codonopsis pilosula, 6-12 parts of Glycyrrhiza uralensis, 2-5 parts of Angelica sinensis, 2-4 parts of Ligusticum chuanxiong, 4-8 parts of Massa fermentata, 5-9 parts of Hordeum vulgare, 6-12 parts of Crataegus pinnatifida, 4-8 parts of Poria cocos, 5-10 parts of Dioscorea opposita, and 3-7 parts of Nelumbo nucifera.

[0030] The modified porous starch-pectin complex is preferably added at a rate of 5% to 10% of the total weight of all natural raw materials.

[0031] The method for preparing a natural spice feed additive to improve pork quality provided by the present invention includes the following steps: P1. Raw material pretreatment and aerobic fermentation: Antioxidant components, flavor components, and spleen-strengthening and absorption-promoting components are pulverized to 40 mesh and mixed evenly. The mixture is then moistened for 2 hours in a sealed, sterile environment at room temperature. The optimal moistening environment temperature is 20–25℃, and the humidity is 45%–55%. The entire process is carried out in a dark, sterile, and sealed environment for 2 hours. A mixed bacterial solution is prepared by combining *Lactobacillus plantarum* with a viable count ≥95% and *Saccharomyces cerevisiae* at a viable count ratio of 1:0.5. After activation at 30℃ for 30 minutes, the solution is inoculated at 3%–5% of the total raw material mass and fermented aerobically at 32℃ for 24 hours.

[0032] P2. Gradient Temperature Controlled Anaerobic Fermentation: The material after aerobic fermentation is transferred to an anaerobic environment with an oxygen content ≤1% and continuous sterile carbon dioxide flow at normal pressure. The relative humidity of the anaerobic environment is 60%–65%, and the temperature is controlled with an error of ±0.5℃. Gradient cooling fermentation is adopted, with a total anaerobic fermentation time of 48 hours. The preferred gradient cooling fermentation is 30℃ for 12 hours, 26℃ for 18 hours, and 22℃ for 18 hours. After impurities are removed through a 40-mesh sieve, the fermentation product is dried at 50℃ using hot air circulation at a wind speed of 1.2 m / s to obtain fermented dry powder.

[0033] P3. Ultrasonic Coupling Modification and Finished Product Refining: The fermented dry powder and modified porous starch-pectin complex were mixed evenly and treated with pulsed ultrasound for 15 minutes under sealed, sterile, light-protected conditions at an ambient temperature of 25℃. The optimal frequency for the pulsed ultrasound was 20kHz, power 300W, and pulse duty cycle 1:1. After ultrasonic treatment, the mixture was allowed to stand for 30 minutes to mature, and then ultra-finely pulverized at 3000r / min using an airflow mill to a D90 particle size of 15-25μm. The moisture content of the material was controlled to ≤8wt%. The mixture was then vacuum-packaged under ambient humidity ≤40% to obtain the finished feed additive. After vacuum packaging, the product was subjected to low-dose irradiation treatment at 3kGy for antibacterial purposes. The shelf life of the finished product at room temperature can reach more than 12 months.

[0034] The feed additive provided by this invention can be used to feed pigs starting two months before slaughter or from 60 kg until slaughter, at a rate of 1% to 2% of the daily feed intake, for two consecutive months. This additive uses natural spices and traditional Chinese medicine components as its core, combined with a modified porous starch-pectin complex. Through dual fermentation and ultrasonic coupling treatment, it can enhance the antioxidant capacity of pork, improve meat flavor and tenderness, reduce drip loss, and simultaneously improve the digestibility and absorption efficiency of pigs, reducing breeding losses. It has no chemical residues and is highly safe.

[0035] Example 1: Preparation of modified porous starch-pectin complex: S1. Preparation of porous starch: Food-grade waxy corn starch was selected and a starch-deionized water suspension with a mass concentration of 30% was prepared. After stirring and dissolving at room temperature, the pH of the suspension was adjusted to 8.5, and a complex enzyme system composed of α-amylase and saccharifying enzyme was added with an enzyme activity ratio of 2:1. The total amount of enzyme added was 0.3 wt% of the dry weight of starch. The system was kept at 55℃ and 80 r / min for constant temperature stirring and enzymatic hydrolysis for 4 h. After enzymatic hydrolysis, the enzyme was inactivated by heating in a 95℃ water bath for 10 min, cooled to room temperature, and the material was repeatedly washed with deionized water until the filtrate was neutral. The material was dried, pulverized, and passed through a 60-mesh sieve to obtain porous starch powder.

[0036] S2. Preparation of pectin gel microspheres: Food-grade citrus pectin was selected and dissolved in room temperature deionized water to prepare a 2.0% (w / w) pectin aqueous solution. The solution was continuously stirred until completely dissolved and no colloidal agglomeration occurred. 0.5 mol / L calcium chloride aqueous solution was added dropwise at a rate of 15% of the volume of the pectin aqueous solution. Ionic crosslinking was carried out for 1.5 h under constant temperature stirring at 50 r / min to form uniform pectin gel microspheres in situ. The gel microspheres were freeze-dried at -40℃ for 12 h. After drying, the microspheres were pulverized and sieved to select powder with a particle size of 10-50 μm to obtain pectin microspheres.

[0037] S3. Weak acid covalent grafting modification: The porous starch obtained in step S1 and the pectin microspheres obtained in step S2 were mixed evenly at a mass ratio of 3:1 to obtain a composite powder. Based on the total mass of the composite powder, 2wt% oligomannose and 0.8wt% sodium glycerophosphate were added respectively, and the mixture was stirred continuously for 20 minutes to ensure that the powder was mixed evenly. Dilute citric acid solution was added dropwise to adjust the pH of the system to be stable at 5.5. The mixed powder was put into a fluidized bed device and the solid-phase composite reaction was carried out for 2 hours under the conditions of 45℃, 75% relative humidity, high-purity nitrogen gas sealing protection, and fluidized bed wind speed of 0.8m / s. The reaction was carried out in the dark throughout. After the reaction, the powder was collected and dried with hot air until the moisture content of the powder was ≤5wt% to obtain the modified porous starch-pectin microsphere composite.

[0038] Natural ingredient mixture: Antioxidant components: 15 parts Eucommia ulmoides leaf, 10 parts Astragalus membranaceus, 10 parts Mulberry leaf, and 4 parts Rosemary.

[0039] Flavor components: 5 parts thyme, 3 parts cloves, 5 parts cinnamon, 4 parts dried ginger, 3 parts Sichuan pepper, 3 parts star anise, and 5 parts dried tangerine peel.

[0040] Spleen-strengthening and absorption-promoting components: Codonopsis pilosula 8 parts, Glycyrrhiza uralensis 6 parts, Angelica sinensis 2 parts, Ligusticum chuanxiong 2 parts, Massa fermentata 4 parts, Hordeum vulgare 5 parts, Crataegus pinnatifida 6 parts, Poria cocos 4 parts, Dioscorea opposita 5 parts, Nelumbo nucifera 3 parts.

[0041] The above-mentioned natural raw materials are mixed, and the amount of modified porous starch-pectin complex added is 5% of the total weight of the natural raw materials.

[0042] Preparation of feed additives: P1. Raw material pretreatment and aerobic fermentation: All natural raw materials are crushed to 40 mesh and mixed evenly. They are moistened for 2 hours in a light-proof, sterile, and sealed environment at 20℃ and 45% humidity. Lactobacillus plantarum and Saccharomyces cerevisiae with a viable count of ≥95% are selected and mixed at a viable count ratio of 1:0.5 to obtain a mixed bacterial solution. After activation at 30℃ for 30 minutes, the solution is inoculated at 3% of the total mass of the raw materials and aerobic fermented at 32℃ for 24 hours.

[0043] P2. Gradient Temperature Controlled Anaerobic Fermentation: The material after aerobic fermentation is transferred to an anaerobic environment with an oxygen content of ≤1% and continuous sterile carbon dioxide flow at normal pressure. The relative humidity of the anaerobic environment is 60%, and the temperature control error is ±0.5℃. Gradient cooling fermentation is adopted, with fermentation at 30℃ for 12h, 26℃ for 18h, and 22℃ for 18h, for a total anaerobic fermentation time of 48h. After impurities are removed by sieving through a 40-mesh sieve, the fermentation product is dried at 50℃ using hot air circulation at a wind speed of 1.2m / s to obtain fermented dry powder.

[0044] P3. Ultrasonic Coupling Modification and Finished Product Refining: The fermented dry powder and the modified porous starch-pectin complex were mixed evenly. Under sealed, sterile, light-proof conditions and an ambient temperature of 25℃, the mixture was treated with pulsed ultrasound at a frequency of 20kHz, a power of 300W, and a pulse duty cycle of 1:1 for 15 minutes. After ultrasonic treatment, the mixture was allowed to stand for 30 minutes to mature. Then, it was ultra-finely pulverized at 3000r / min airflow to a particle size of 15μm with a D90 diameter. The moisture content of the material was controlled to be ≤8wt%. The mixture was vacuum-packed under ambient humidity of ≤40% and treated with low-dose irradiation of 3kGy to obtain the finished feed additive.

[0045] Feeding application: Start feeding pigs when they reach 60 kg and continue until slaughter, adding 1% of their daily feed amount for 2 months.

[0046] Example 2: Preparation of modified porous starch-pectin complex: S1. Preparation of porous starch: Food-grade waxy corn starch was selected and a starch-deionized water suspension with a mass concentration of 30% was prepared. After stirring and dissolving at room temperature, the pH of the suspension was adjusted to 8.5, and a complex enzyme system composed of α-amylase and saccharifying enzyme was added with an enzyme activity ratio of 2:1. The total amount of enzyme added was 0.3 wt% of the dry weight of starch. The system was kept at 55℃ and 80 r / min for constant temperature stirring and enzymatic hydrolysis for 4 h. After enzymatic hydrolysis, the enzyme was inactivated by heating in a 95℃ water bath for 10 min, cooled to room temperature, and the material was repeatedly washed with deionized water until the filtrate was neutral. The material was dried, pulverized, and passed through a 60-mesh sieve to obtain porous starch powder.

[0047] S2. Preparation of pectin gel microspheres: Food-grade citrus pectin was selected and dissolved in room temperature deionized water to prepare a 2.0% (w / w) pectin aqueous solution. The solution was continuously stirred until completely dissolved and no colloidal agglomeration occurred. 0.5 mol / L calcium chloride aqueous solution was added dropwise at a rate of 20% of the volume of the pectin aqueous solution. Ionic crosslinking was carried out for 1.5 h under constant temperature stirring at 50 r / min to form uniform pectin gel microspheres in situ. The gel microspheres were freeze-dried at -40℃ for 12 h. After drying, the microspheres were pulverized and sieved to select powder with a particle size of 10-50 μm to obtain pectin microspheres.

[0048] S3. Weak acid covalent grafting modification: The porous starch obtained in step S1 and the pectin microspheres obtained in step S2 were mixed evenly at a mass ratio of 3:1 to obtain a composite powder. Based on the total mass of the composite powder, 2wt% oligomannose and 0.8wt% sodium glycerophosphate were added respectively, and the mixture was stirred continuously for 20 minutes to ensure that the powder was mixed evenly. Dilute citric acid solution was added dropwise to adjust the pH of the system to be stable at 6.0. The mixed powder was put into a fluidized bed device and subjected to solid-phase composite reaction for 2 hours under the conditions of 45℃, 75% relative humidity, high-purity nitrogen gas sealing protection, and fluidized bed wind speed of 0.8m / s. The reaction was carried out in the dark throughout. After the reaction, the powder was collected and dried with hot air until the moisture content of the powder was ≤5wt% to obtain the modified porous starch-pectin microsphere composite.

[0049] Natural ingredient mixture: Antioxidant components: 25 parts Eucommia ulmoides leaf, 20 parts Astragalus membranaceus, 18 parts Mulberry leaf, and 9 parts Rosemary.

[0050] Flavor components: 10 parts thyme, 8 parts cloves, 10 parts cinnamon, 8 parts dried ginger, 6 parts Sichuan pepper, 7 parts star anise, and 10 parts dried tangerine peel.

[0051] Spleen-strengthening and absorption-promoting components: Codonopsis pilosula 15 parts, Glycyrrhiza uralensis 12 parts, Angelica sinensis 5 parts, Ligusticum chuanxiong 4 parts, Massa fermentata 8 parts, Hordeum vulgare 9 parts, Crataegus pinnatifida 12 parts, Poria cocos 8 parts, Dioscorea opposita 10 parts, Nelumbo nucifera 7

[0052] The above-mentioned natural raw materials are mixed, and the amount of modified porous starch-pectin complex added is 10% of the total weight of the natural raw materials.

[0053] Preparation of feed additives: P1. Raw material pretreatment and aerobic fermentation: All natural raw materials are crushed to 40 mesh and mixed evenly. They are moistened for 2 hours in a light-proof, sterile, and sealed environment at 25℃ and 55% humidity. Lactobacillus plantarum and Saccharomyces cerevisiae with a viable count of ≥95% are selected and mixed at a viable count ratio of 1:0.5 to obtain a mixed bacterial solution. After activation at 30℃ for 30 minutes, 5% of the total mass of raw materials is inoculated and aerobic fermentation is carried out at a constant temperature of 32℃ for 24 hours.

[0054] P2. Gradient Temperature Controlled Anaerobic Fermentation: The material after aerobic fermentation is transferred to an anaerobic environment with an oxygen content of ≤1% and continuous sterile carbon dioxide flow at normal pressure. The relative humidity of the anaerobic environment is 65%, and the temperature control error is ±0.5℃. Gradient cooling fermentation is adopted, with fermentation at 30℃ for 12h, 26℃ for 18h, and 22℃ for 18h, for a total anaerobic fermentation time of 48h. After impurities are removed by sieving through a 40-mesh sieve, the fermentation product is dried at 50℃ using hot air circulation at a wind speed of 1.2m / s to obtain fermented dry powder.

[0055] P3. Ultrasonic Coupling Modification and Finished Product Refining: The fermented dry powder and the modified porous starch-pectin complex were mixed evenly. Under sealed, sterile, light-proof conditions and an ambient temperature of 25℃, the mixture was treated with pulsed ultrasound at a frequency of 20kHz, a power of 300W, and a pulse duty cycle of 1:1 for 15 minutes. After ultrasonic treatment, the mixture was allowed to stand for 30 minutes to mature. Then, it was ultra-finely pulverized at 3000r / min airflow to a particle size of 25μm (D90). The moisture content of the material was controlled to be ≤8wt%. The mixture was vacuum-packed under ambient humidity of ≤40% and treated with low-dose irradiation of 3kGy to inhibit bacterial growth, thus obtaining the finished feed additive.

[0056] Feeding application: Start feeding the pigs 2 months before slaughter and continue until slaughter, adding 2% of the daily feed amount for 2 months.

[0057] Example 3: Preparation of modified porous starch-pectin complex: S1. Preparation of porous starch: Food-grade waxy corn starch was selected and a starch-deionized water suspension with a mass concentration of 30% was prepared. After stirring and dissolving at room temperature, the pH of the suspension was adjusted to 8.5, and a complex enzyme system composed of α-amylase and saccharifying enzyme was added with an enzyme activity ratio of 2:1. The total amount of enzyme added was 0.3 wt% of the dry weight of starch. The system was kept at 55℃ and 80 r / min for constant temperature stirring and enzymatic hydrolysis for 4 h. After enzymatic hydrolysis, the enzyme was inactivated by heating in a 95℃ water bath for 10 min, cooled to room temperature, and the material was repeatedly washed with deionized water until the filtrate was neutral. The material was dried, pulverized, and passed through a 60-mesh sieve to obtain porous starch powder.

[0058] S2. Preparation of pectin gel microspheres: Food-grade citrus pectin was selected and dissolved in room temperature deionized water to prepare a 2.0% (w / w) pectin aqueous solution. The solution was continuously stirred until completely dissolved and no colloidal agglomeration occurred. 0.5 mol / L calcium chloride aqueous solution was added dropwise at a rate of 18% (w / w) of the volume of the pectin aqueous solution. Ionic crosslinking was carried out for 1.5 h under constant temperature stirring at 50 r / min to form uniform pectin gel microspheres in situ. The gel microspheres were freeze-dried at -40℃ for 12 h. After drying, the microspheres were pulverized and sieved to select powder with a particle size of 10-50 μm to obtain pectin microspheres.

[0059] S3. Weak acid covalent grafting modification: The porous starch obtained in step S1 and the pectin microspheres obtained in step S2 were mixed evenly at a mass ratio of 3:1 to obtain a composite powder. Based on the total mass of the composite powder, 2wt% oligomannose and 0.8wt% sodium glycerophosphate were added respectively, and the mixture was stirred continuously for 20 minutes to ensure that the powder was mixed evenly. Dilute citric acid solution was added dropwise to adjust the pH of the system to be stable at 5.8. The mixed powder was put into a fluidized bed device and the solid-phase composite reaction was carried out for 2 hours under the conditions of 45℃, 75% relative humidity, high-purity nitrogen gas sealing protection, and fluidized bed wind speed of 0.8m / s. The reaction was carried out in the dark throughout. After the reaction, the powder was collected and dried with hot air until the moisture content of the powder was ≤5wt% to obtain the modified porous starch-pectin microsphere composite.

[0060] Natural ingredient mixture: Antioxidant components: 20 parts Eucommia ulmoides leaf, 15 parts Astragalus membranaceus, 14 parts Mulberry leaf, and 6 parts Rosemary.

[0061] Flavor components: 8 parts thyme, 5 parts cloves, 8 parts cinnamon, 6 parts dried ginger, 5 parts Sichuan pepper, 5 parts star anise, and 8 parts dried tangerine peel.

[0062] Spleen-strengthening and absorption-promoting components: Codonopsis pilosula 12 parts, Glycyrrhiza uralensis 9 parts, Angelica sinensis 3 parts, Ligusticum chuanxiong 3 parts, Massa fermentata 6 parts, Hordeum vulgare 7 parts, Crataegus pinnatifida 9 parts, Poria cocos 6 parts, Dioscorea opposita 8 parts, Nelumbo nucifera 5 parts.

[0063] The above-mentioned natural raw materials are mixed, and the amount of modified porous starch-pectin complex added is 7% of the total weight of the natural raw materials.

[0064] Preparation of feed additives: P1. Raw material pretreatment and aerobic fermentation: All natural raw materials are crushed to 40 mesh and mixed evenly. They are moistened for 2 hours in a light-proof, sterile, and sealed environment at 23℃ and 50% humidity. Lactobacillus plantarum and Saccharomyces cerevisiae with a viable count of ≥95% are selected and mixed at a viable count ratio of 1:0.5 to obtain a mixed bacterial solution. After activation at 30℃ for 30 minutes, the solution is inoculated at 4% of the total mass of the raw materials and aerobic fermented at 32℃ for 24 hours.

[0065] P2. Gradient Temperature Controlled Anaerobic Fermentation: The material after aerobic fermentation is transferred to an anaerobic environment with an oxygen content of ≤1% and continuous sterile carbon dioxide flow at normal pressure. The relative humidity of the anaerobic environment is 63%, and the temperature control error is ±0.5℃. Gradient cooling fermentation is adopted, with fermentation at 30℃ for 12h, 26℃ for 18h, and 22℃ for 18h, for a total anaerobic fermentation time of 48h. After impurities are removed by sieving through a 40-mesh sieve, the fermentation product is dried at 50℃ using hot air circulation at a wind speed of 1.2m / s to obtain fermented dry powder.

[0066] P3. Ultrasonic Coupling Modification and Finished Product Refining: The fermented dry powder and the modified porous starch-pectin complex were mixed evenly. Under sealed, sterile, light-proof conditions and an ambient temperature of 25℃, the mixture was treated with pulsed ultrasound at a frequency of 20kHz, a power of 300W, and a pulse duty cycle of 1:1 for 15 minutes. After ultrasonic treatment, the mixture was allowed to stand for 30 minutes to mature. Then, it was ultra-finely pulverized at 3000r / min airflow to a particle size of 20μm (D90). The moisture content of the material was controlled to ≤8wt%. The mixture was vacuum-packed under ambient humidity of ≤40% and treated with low-dose irradiation of 3kGy to obtain the finished feed additive.

[0067] Feeding application: Start feeding when pigs weigh 60 kg until slaughter, add 1.5% of the daily feed amount, and continue for 2 months.

[0068] Comparative Example 1: The difference from Example 3 is that no modified porous starch-pectin complex is added, while the other raw material ratios, preparation processes, and feeding methods are exactly the same.

[0069] Comparative Example 2: The difference from Example 3 is that gradient temperature-controlled anaerobic fermentation is not carried out in the preparation process; instead, constant temperature 30℃ anaerobic fermentation is used for 48 hours. The other raw material ratios, process steps, and feeding methods are exactly the same.

[0070] Comparative Example 3: The difference from Example 3 is that no antioxidant or flavor components are added, only the spleen-strengthening and absorption-promoting components are retained, while the other raw material ratios, preparation processes, and feeding methods are exactly the same.

[0071] Comparative Example 4: The difference from Example 3 is that ultrasonic coupling modification is not performed during the preparation process, while the other raw material ratios, process steps, and feeding methods are exactly the same.

[0072] test: Experiment 1: Pork dripping water loss test: 1.1 Experimental Objective: To test the effects of the natural spice feed additives in Examples 1-3 and Comparative Examples 1-4 on the drip loss rate of pork after slaughter, and to verify the effects of modified porous starch-pectin complex, gradient anaerobic fermentation, antioxidant flavor components, and ultrasonic coupling modification on the water retention properties of pork. A lower drip loss rate indicates better water retention and more tender meat.

[0073] 1.2 Experimental Principle The water retention capacity of pork directly affects the meat's texture and yield. The integrity of muscle cell membranes and the water-holding capacity between cells determine the degree of water loss. This experiment simulates circulation storage conditions by refrigerating the meat at 4℃ for 24 hours. The difference in weight of the meat before and after refrigeration is measured to calculate the drip loss rate, directly reflecting the effect of feed additives on improving the water retention capacity of pork.

[0074] 1.3 Experimental Instruments and Reagents Experimental Instruments: Electronic balance (accuracy 0.001g), 4℃ constant temperature refrigerator, sterile sealed container, qualitative filter paper Experimental Materials: Examples 1-3, Comparative Examples 1-4, feed additives, basal diet, longissimus dorsi muscle samples from three-way crossbred pigs 1.4 Test Methods: Drip loss rate test: ① Seventy three-way crossbred pigs weighing 60 kg and in uniform health were selected and randomly divided into seven groups of 10 pigs each: Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4. A blank control group was also set up (fed only the basal diet).

[0075] ② Each experimental group was fed according to the corresponding plan until slaughter. After slaughter, the longissimus dorsi muscle of the 6th-7th rib on the left side was uniformly taken, trimmed into 50.000g standard meat pieces, and accurately weighed and recorded as the initial weight.

[0076] ③ Place the meat pieces in a sterile, sealed container and refrigerate at a constant temperature of 4℃ for 24 hours.

[0077] ④ Remove the meat pieces, gently absorb the surface moisture with qualitative filter paper, and weigh them again accurately as the final weight.

[0078] ⑤ Calculate the drip loss rate: Drip loss rate = (initial mass - final mass) / initial mass × 100%. Each sample is tested in parallel 3 times, and the average value is taken as the final result.

[0079] 1.5 Experimental Data: Table 1

[0080] As shown in Experiment 1, the drip loss rates of Examples 1-3 were significantly lower than those of the blank control group and the comparative examples, indicating excellent water retention. Comparing Example 3 with Comparative Example 1: Comparative Example 1 did not add the modified porous starch-pectin complex, resulting in the loss of the sustained-release carrier and adsorption protection of the active ingredients, a significant decrease in utilization, reduced muscle cell membrane integrity, and a drip loss rate increasing from 1.96% to 3.87%, indicating a significant decrease in water retention. Comparing Example 3 with Comparative Example 2: Comparative Example 2 did not employ gradient temperature-controlled anaerobic fermentation, leading to insufficient conversion of active substances in the raw materials and no improvement in the water-holding structure between muscle cells, resulting in a drip loss rate of 3.21%. Comparing Example 3 with Comparative Example 3: Comparative Example 3 did not add antioxidant and flavor components, making the muscle prone to lipid oxidation, exacerbating cell membrane damage, and causing severe water loss, with a drip loss rate of 4.15%. Comparing Example 3 with Comparative Example 4: Comparative Example 4 did not undergo ultrasonic coupling modification, resulting in uneven dispersion of active ingredients, low absorption efficiency, and a weaker water retention effect than the examples, with a drip loss rate of 2.78%. In summary, the synergistic effect of modified porous starch-pectin complex, gradient anaerobic fermentation, antioxidant flavor components, and ultrasonic coupling modification can significantly reduce drip loss and improve meat quality.

[0081] Experiment 2: Pork tenderness (shear force) test: 1.1 Experimental Objective To test the effect of feed additives in Examples 1-3 and Comparative Examples 1-4 on the shear force of pork. The lower the shear force value, the better the tenderness of the pork. This experiment aims to verify the effect of each technical feature on improving the tenderness of the muscle.

[0082] 1.2 Experimental Principle: The tenderness of pork is determined by the thickness of muscle fibers, the solubility of collagen, and the distribution of intramuscular fat. By shearing a standard meat column after heating using a texture analyzer, the maximum shear force required is measured, which quantitatively characterizes tenderness; the smaller the value, the better the tenderness.

[0083] 1.3 Experimental Instruments and Reagents Experimental Instruments: Texture analyzer, constant temperature water bath, circular sampler (Φ10mm), cutting tool, electronic balance Experimental Materials: Longissimus dorsi muscle samples from the same batch as Experiment 1, Examples 1-3, Comparative Examples 1-4, feed additives; 1.4 Test Methods: Shear force test: ① Take the longissimus dorsi muscle sample from Experiment 1 and remove the surface fascia and connective tissue.

[0084] ②Place the meat pieces in an 80℃ constant temperature water bath and heat until the center temperature of the meat pieces stabilizes at 70℃. Maintain this temperature for 10 minutes to allow the muscle to fully cook.

[0085] ③ After cooling to room temperature, use a Φ10mm circular sampler to drill a standard muscle column along the direction perpendicular to the muscle fibers.

[0086] ④ A shear test was performed using a texture analyzer at a shear rate of 200 mm / min, and the maximum shear force (N) was recorded.

[0087] ⑤ Each sample was measured in parallel three times, and the average value was taken as the final shear force value.

[0088] 1.5 Experimental Data: Table 2

[0089] Experiment 2 results showed that the shear force of Examples 1-3 was significantly lower than that of the blank control group and the comparative example, indicating a significant improvement in tenderness. Comparative Example 1 lacked the modified porous starch-pectin complex, preventing the active ingredients from continuously softening the muscle fibers, resulting in strong muscle fiber toughness and a significantly increased shear force of 45.72 N. Comparative Example 2 did not undergo gradient anaerobic fermentation, leading to insufficient release of spleen-strengthening and absorption-promoting components and tenderizing agents, resulting in insufficient nutrient absorption in the pigs, coarse and hard muscle fibers, and a shear force of 40.25 N. Comparative Example 3 did not add antioxidants or flavor components; muscle oxidation led to increased cross-linking of muscle fibers and enhanced toughness, resulting in a shear force of 48.31 N, close to that of the blank control group. Comparative Example 4 did not undergo ultrasonic coupling modification, resulting in poor penetration and dispersion of active ingredients, insufficient muscle softening, and a shear force higher than the example groups. These results demonstrate that the four inventive features of this invention work synergistically to effectively soften muscle fibers and significantly improve pork tenderness.

[0090] Experiment 3: Antioxidant properties of pork (MDA content) test: 1.1 Experimental Objective To test the effect of feed additives in Examples 1-3 and Comparative Examples 1-4 on the malondialdehyde (MDA) content in pork. MDA is an end product of lipid oxidation. The lower the content, the stronger the antioxidant capacity of pork, the longer the shelf life, and the more stable the quality.

[0091] 1.2 Experimental Principle After slaughter, pig muscle is prone to lipid oxidation, producing harmful substances such as MDA, leading to poor meat quality and off-flavors. The thiobarbituric acid (TBA) method is used to detect MDA content, which can quantitatively evaluate the antioxidant capacity of muscle.

[0092] 1.3 Test Instruments and Reagents Test Instruments: UV-Vis spectrophotometer, high-speed refrigerated centrifuge, constant temperature water bath, vortex shaker, electronic balance Test Reagents: trichloroacetic acid, thiobarbituric acid, toluene, Examples 1-3, Comparative Examples 1-4 feed additives, pork tissue samples; 1.4 Test Methods: MDA content test: ① Take a sample of the longissimus dorsi muscle that has been refrigerated at 4℃ for 48 hours after slaughter, and accurately weigh 5.000g into a centrifuge tube.

[0093] ② Add 25 mL of 5% trichloroacetic acid solution, vortex for 3 min, and extract at room temperature for 30 min.

[0094] ③ Centrifuge at 8000 r / min for 15 min, and filter the supernatant for later use.

[0095] ④ Take 5 mL of filtrate, add 5 mL of 0.02 mol / L thiobarbituric acid solution, mix well, and heat in a 95°C water bath for 40 min.

[0096] ⑤ Cool to room temperature, measure the absorbance at 532 nm, and calculate the MDA content (mg / kg) based on the standard curve.

[0097] ⑥ Each sample was tested in parallel three times, and the average value was taken as the final result.

[0098] 1.5 Experimental Data: Table 3

[0099] Experiment 3 data showed that the MDA content of Examples 1-3 was significantly lower than that of the blank control group and the comparative examples, indicating extremely strong antioxidant capacity in the muscle. Comparative Example 1, lacking the modified porous starch-pectin complex, could not stably release antioxidant components, leading to accelerated lipid oxidation in the muscle and an MDA content as high as 0.57 mg / kg. Comparative Example 2 did not employ gradient anaerobic fermentation, resulting in insufficient activation of antioxidant components, decreased free radical scavenging ability, and significant accumulation of oxidation products. Comparative Example 3, without added antioxidant components, lacked antioxidant protection in the muscle, resulting in severe lipid oxidation and an MDA content of 0.63 mg / kg, close to the blank control group. Comparative Example 4, without ultrasonic coupling modification, exhibited uneven dispersion of antioxidant components, low bioavailability, and a weaker antioxidant effect than the example groups. In summary, the various technical features of this invention synergistically enhance the antioxidant capacity of muscle, effectively inhibit lipid oxidation, extend the shelf life of pork, and stabilize meat flavor.

[0100] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A natural spice feed additive for improving pork quality, characterized in that, It is made from the following natural raw materials in parts by weight, and a modified porous starch-pectin complex accounting for 5% to 10% of the total weight of all natural raw materials; The natural ingredients include: antioxidant components and spleen-strengthening and absorption-promoting components; The antioxidant components include: 15-25 parts of Eucommia ulmoides leaves, 10-20 parts of Astragalus membranaceus, 10-18 parts of mulberry leaves, and 4-9 parts of rosemary; The antioxidant components include: 5-10 parts thyme, 3-8 parts cloves, 5-10 parts cinnamon, 4-8 parts dried ginger, 3-6 parts Sichuan pepper, 3-7 parts star anise, and 5-10 parts dried tangerine peel; The spleen-strengthening and absorption-promoting components include: 8-15 parts of Codonopsis pilosula, 6-12 parts of Glycyrrhiza uralensis, 2-5 parts of Angelica sinensis, 2-4 parts of Ligusticum chuanxiong, 4-8 parts of Massa fermentata, 5-9 parts of Hordeum vulgare, 6-12 parts of Crataegus pinnatifida, 4-8 parts of Poria cocos, 5-10 parts of Dioscorea opposita, and 3-7 parts of Nelumbo nucifera.

2. The natural spice feed additive for improving pork quality according to claim 1, characterized in that, The modified porous starch-pectin complex is prepared by a method comprising the following steps: S1. Preparation of porous starch: Food-grade waxy corn starch was selected and a starch-deionized water suspension with a mass concentration of 30% was prepared. After stirring and dissolving at room temperature, the pH of the suspension was adjusted to 8.5, and a complex enzyme system composed of α-amylase and saccharifying enzyme was added. The total amount of enzyme added was 0.3 wt% of the dry weight of starch. The system was kept at 55℃ and 80 r / min for constant temperature stirring and enzymatic hydrolysis for 4 h. After the enzymatic hydrolysis was completed, the enzyme was inactivated by heating in a 95℃ water bath for 10 min, cooled to room temperature, and the material was repeatedly washed with deionized water until the filtrate was neutral. The material was dried, pulverized, and passed through a 60-mesh sieve to obtain porous starch powder. S2. Preparation of pectin gel microspheres: Food-grade citrus pectin was selected and dissolved in room temperature deionized water to prepare a 2.0% (w / w) pectin aqueous solution. The solution was continuously stirred until completely dissolved and no colloidal agglomeration occurred. 0.5 mol / L calcium chloride aqueous solution was added dropwise at a rate of 15%–20% of the volume of the pectin aqueous solution. Ionic crosslinking was carried out for 1.5 h under constant temperature stirring at 50 r / min to form uniform pectin gel microspheres in situ. The gel microspheres were freeze-dried at -40℃ for 12 h. After drying, the microspheres were pulverized and sieved to select powder with a particle size of 10–50 μm to obtain pectin microspheres. S3. Weak acid covalent grafting modification: The porous starch obtained in step S1 and the pectin microspheres obtained in step S2 are mixed evenly at a mass ratio of 3:1 to obtain a composite powder. Based on the total mass of the composite powder, 2wt% oligomannose and 0.8wt% sodium glycerophosphate are added respectively, and the mixture is stirred continuously for 20 minutes to ensure uniform mixing. Dilute citric acid solution is added dropwise to adjust the pH of the system to be stable at 5.5-6.

0. The mixed powder is put into a fluidized bed device and subjected to solid-phase composite reaction for 2 hours under the conditions of 45℃, 75% relative humidity, high-purity nitrogen gas sealing protection, and fluidized bed wind speed of 0.8m / s. The reaction is carried out in the dark throughout. After the reaction, the powder is collected and dried with hot air until the powder moisture content is ≤5wt% to obtain the modified porous starch-pectin microsphere composite.

3. The natural spice feed additive for improving pork quality according to claim 2, characterized in that, The ratio of α-amylase to glucoamylase activity in the complex enzyme system is 2:

1.

4. The natural spice feed additive for improving pork quality according to claim 1, characterized in that, The feed additive is to be added to pigs starting two months before slaughter or starting when they reach 60 kg and continue until slaughter, at a rate of 1-2% of the daily feed intake, for two consecutive months.

5. A method for preparing a natural spice feed additive for improving pork quality according to any one of claims 1-4, characterized in that, Includes the following steps: P1. Raw material pretreatment and aerobic fermentation: The antioxidant components, flavor precursor components, and spleen-strengthening and absorption-promoting components are pulverized to 40 mesh and mixed evenly. The mixture is moistened for 2 hours in a sealed and sterile environment at room temperature. Lactobacillus plantarum with a viable count of ≥95% and Saccharomyces cerevisiae were selected and mixed at a viable count ratio of 1:0.5 to obtain a mixed bacterial solution. After activation at 30℃ for 30 min, the solution was inoculated at 3% to 5% of the total mass of raw materials and fermented at 32℃ for 24 h under constant temperature aerobic conditions. P2. Gradient temperature-controlled anaerobic fermentation: The material after aerobic fermentation is transferred to an anaerobic environment with an oxygen content of ≤1% and continuous sterile carbon dioxide flow at normal pressure. The relative humidity of the anaerobic environment is 60%~65%, and the temperature control error is ±0.5℃. Gradient cooling fermentation is adopted, and the total anaerobic fermentation time is 48h. After the fermentation product is filtered through a 40-mesh sieve to remove impurities, it is dried at 50℃ using hot air circulation at a wind speed of 1.2m / s to obtain fermented dry powder. P3. Ultrasonic Coupling Modification and Finished Product Refining: The fermented dry powder and the modified porous starch-pectin complex are mixed evenly. Under sealed, sterile, light-proof conditions and an ambient temperature of 25°C, pulsed ultrasound is used for 15 minutes as an auxiliary treatment. After ultrasonic treatment, the mixture is allowed to stand and mature for 30 minutes. Then, it is ultra-finely pulverized at 3000 r / min airflow to a particle size of 15-25 μm (D90). The moisture content of the material is controlled to ≤8 wt%. The mixture is vacuum-packed under ambient humidity ≤40% to obtain the finished feed additive.

6. The method for preparing the natural spice feed additive for improving pork quality according to claim 5, characterized in that, In step P1, the ambient temperature for moistening is 20-25℃ and the ambient humidity is 45%-55%. The entire process is carried out in a dark, sterile, and sealed environment for 2 hours.

7. The method for preparing the natural spice feed additive for improving pork quality according to claim 5, characterized in that, In step P2, a gradient cooling fermentation method was used: fermentation at 30℃ for 12 hours, at 26℃ for 18 hours, and at 22℃ for 18 hours, for a total anaerobic fermentation time of 48 hours.

8. The method for preparing the natural spice feed additive for improving pork quality according to claim 5, characterized in that, In step P3, the frequency of the pulsed ultrasound is 20kHz, the power is 300W, and the pulse duty cycle is 1:

1.

9. The method for preparing the natural spice feed additive for improving pork quality according to claim 5, characterized in that, After vacuum packaging, the product is subjected to low-dose irradiation treatment of 3kGy for sterilization, and the shelf life of the finished product at room temperature can reach more than 12 months.

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