Pet solid food capable of improving immunity of pets and preparation method of pet solid food

Abstract

The preparation method comprises the following steps: (1) compounding hermetia illucens larvae, whole tenebrio molitor and euphausia superba according to a mass ratio of (3-5): (2-4): 1, carrying out enzymolysis, and reacting with a yeast cell wall extract to form a glycopeptide compound; (2) coating the glycopeptide compound with a mannan oligosaccharide and chitosan solution to form microcapsules, and controlling the release rate of the microcapsules in simulated gastric juice to be lower than 30% and the release rate of the microcapsules in simulated intestinal juice to be higher than 80%; (3) co-fermenting the microcapsules, clostridium butyricum and pediococcus acidilactici, and adsorbing fermentation liquor on the porous starch; (4) performing dry mixing on the functional compound, the fermentation compound and the base material, and performing low-temperature puffing; and (5) sequentially spraying a vitamin D3 grease layer, a pectin-whey protein protective layer and a solution containing TGF-beta2 on the surfaces of the particles. Through cooperation of multiple processes, the immune function and intestinal health of pets are remarkably improved, and the product is good in stability and palatability.

Description

Technical Field

[0001] This invention belongs to the field of pet food, specifically, it relates to a dry pet food that can improve the immunity of pets and its preparation method. Background Technology

[0002] As pets play an increasingly important emotional role in families, the market demand for high-quality dry pet food that combines nutrition and health benefits is becoming increasingly urgent. A pet's long-term health highly depends on the stability and balance of its immune system, and scientific nutritional intervention is a core approach to building this foundation. Currently, commercially available dry pet food faces systemic technological bottlenecks in achieving effective immune support.

[0003] Mainstream products primarily rely on traditional livestock and poultry meat and fishmeal as protein sources, facing not only resource and cost pressures but also the problem of limited functionality. Although some studies have attempted to enhance immunity by adding single functional ingredients (such as β-glucan or nucleotides), these ingredients are easily inactivated during processing, storage, and pet digestion, and lack synergistic effects, resulting in ultimately unsatisfactory results. Furthermore, while novel sustainable resources such as insect protein hold great potential, their application faces two challenges: firstly, simple physical processing or single enzymatic hydrolysis cannot effectively release and stabilize their immunomodulatory activity; secondly, the unpleasant flavor of the raw materials themselves and the bitter peptides produced by enzymatic hydrolysis severely restrict the palatability of the products.

[0004] Fundamentally, existing technologies are mostly limited to optimizing single processes, such as focusing only on enzymatic hydrolysis or simple encapsulation, failing to construct a synergistic process system that integrates multiple objectives such as "active release, stabilization protection, targeted delivery, and flavor improvement." Therefore, there is an urgent need in this field for an innovative and systematic technical solution that can transform novel protein sources such as insects into core ingredients with high digestibility, rich in stable immune-active components, and excellent palatability through interconnected processing and modification processes. This would enable the development of a new generation of pet dry food that can effectively, gently, and systematically enhance pet immunity. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a pet dry food that can improve pet immunity and its preparation method, the details of which are as follows: A method for preparing dry pet food that can improve a pet's immunity includes the following steps: (1) Preparation of functional complex: Black soldier fly larvae, whole yellow mealworms and Antarctic krill were compounded in a mass ratio of (3~5):(2~4):1, crushed and mixed with water to form a compound animal protein slurry; the pH of the compound animal protein slurry was adjusted to 6.0~7.0, and enzymatic hydrolysis was performed using a compound protease composed of endopeptide and exopeptide in a mass ratio of (2~4):1, and the degree of protein hydrolysis was controlled between 18~22%; then, yeast cell wall extract containing β-glucan was added at 1~3% of the mass of the compound animal protein slurry, and the mixture was stirred at 50~60℃ to allow the enzymatically hydrolyzed peptides to combine with β-glucan to form a stable glycopeptide complex; (2) Preparation of encapsulated microcapsules: Using mannan oligosaccharide and chitosan solution, the glycopeptide complex obtained in step (1) is encapsulated into microcapsules with a particle size of 50~200μm, and the release rate of the microcapsules is controlled to be less than 30% in simulated gastric fluid within 2 hours and more than 80% in simulated intestinal fluid within 4 hours; (3) Preparation of fermentation complex: The microcapsules obtained in step (2) are mixed with Clostridium butyricum and Pediococcus lactis in a mass ratio of (5~8):1:1, and fermented together at 37°C for 24~48 hours under anaerobic conditions to obtain a fermentation broth rich in short-chain fatty acids; then, the fermentation broth is adsorbed onto porous starch to form a fermentation complex. (4) Preparation of dry food matrix: The functional complex obtained in step (1) and the fermentation complex obtained in step (3) are dry mixed with meat powder, grain base and vitamin and mineral premix, wherein the amount of the functional complex added is 8~15% of the total mass of the dry mixture and the amount of the fermentation complex added is 3~8%; after the mixed powder is conditioned, it is low temperature puffed at a die temperature of 85~90℃. (5) Coating the surface of the granules: The surface of the puffed granules obtained in step (4) is sequentially coated with an oil layer containing vitamin D3, a protective layer composed of pectin and whey protein, and a solution containing 0.02~0.03% transforming growth factor-β2 (TGF-β2); (6) The final product is packaged using light-proof and oxygen-proof packaging materials.

[0006] Furthermore, in step (1), the hydrated particle size of the stable glycopeptide complex is distributed in the range of 100-500 nm. By precisely controlling the hydrated particle size of the glycopeptide complex, not only is good dispersion stability of the complex in solution ensured, avoiding precipitation and aggregation, but this specific particle size range is also more conducive to the recognition and absorption by intestinal epithelial cells, thereby increasing the bioavailability of the immune active ingredient by more than 30%.

[0007] Furthermore, in step (2), the mass ratio of mannooligosaccharide to chitosan is (1:1) to (2:1), and the encapsulation efficiency of the microcapsules is not less than 85%. By limiting the specific ratio of mannooligosaccharide to chitosan, a microcapsule wall material with an ideal network structure can be formed, which not only ensures the structural density to achieve a high encapsulation efficiency of more than 85%, but also has suitable permeability to achieve the intestinal targeted release function. At the same time, the wall material also has good biocompatibility and degradability.

[0008] Furthermore, in step (3), the butyric acid content in the short-chain fatty acids produced by the co-fermentation process is not less than 25%. By controlling the butyric acid content in the fermentation product, the fermentation complex is ensured to have excellent intestinal barrier repair function and anti-inflammatory activity. As the preferred energy source for intestinal epithelial cells, butyric acid can effectively promote the expression of tight junction proteins, enhance intestinal barrier function, and provide a solid foundation for systemic immune regulation.

[0009] Furthermore, in step (3), the porous starch has a pore size range of 5~20 μm. This specific pore size range can provide a sufficiently large specific surface area to achieve efficient adsorption of the fermentation broth (adsorption amount reaches 1.5~2.5 times the carrier mass), maintain the stability of the fermentation product through capillary action, and provide suitable release kinetics to prolong the action time of functional components in the intestine.

[0010] Furthermore, in step (4), the screw speed for low-temperature puffing is 150~200 rpm, and the residence time of the material in the puffing machine is less than 30 seconds. By using a specific combination of low-temperature puffing parameters, while ensuring that the particles obtain ideal puffing degree and palatability, the activity loss of heat-sensitive functional components can be controlled within 15%, thus maximizing the preservation of the functional characteristics of immune-active components.

[0011] Furthermore, in step (5), the mass ratio of pectin to whey protein in the protective layer is (3:1) to (5:1). The composite protective layer formed by pectin and whey protein in a specific mass ratio has good pH response characteristics. It can maintain its structural integrity for more than 2 hours in the strongly acidic environment of the stomach, effectively protecting sensitive components such as TGF-β2 from gastric acid damage, while it can be rapidly degraded in the neutral environment of the intestine, achieving precise release of functional components.

[0012] This invention also provides a pet dry food prepared by the above-described method. This pet dry food can enhance the immune function of pets, specifically by increasing the proportion of regulatory T cells (Tregs) in the peripheral blood of pets by at least 20% after four weeks of continuous feeding. Furthermore, the dry food can improve the intestinal health of pets, specifically by increasing the butyrate content in pet feces by more than 30% after four weeks of continuous feeding. The pet dry food prepared by this method exhibits a significant synergistic effect among its functional components. Glycopeptide complexes, prebiotic-postbiotic complexes, and immunomodulatory factors form a multi-level, multi-target immunomodulatory network, achieving comprehensive immune enhancement from the molecular to the systemic level, with a gentle and long-lasting effect and no risk of over-activation. This pet dry food effectively enhances the body's immune regulation capacity by specifically increasing the proportion of regulatory T cells (Tregs) by at least 20%, thereby enhancing the body's immune tolerance while maintaining stable IgE levels. This demonstrates its excellent immune balance regulation function and avoids the excessive inflammatory response that may be caused by traditional immune enhancers. In addition, this pet dry food can significantly improve gut health by increasing butyrate content by more than 30% to effectively enhance intestinal barrier function, while also increasing the Shannon diversity index of gut microbiota, promoting the proliferation of beneficial bacteria, inhibiting the growth of pathogens, providing a solid foundation for systemic immunity, and forming a virtuous cycle of gut-axis.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: I. This invention achieves amino acid complementarity of animal proteins from different sources by scientifically combining black soldier fly larvae, whole mealworms, and Antarctic krill in a specific mass ratio of (3~5):(2~4):1. Furthermore, by combining endopeptidase and exopeptidase in a specific ratio of (2~4):1, the synergistic enzymatic hydrolysis not only significantly improves the protein hydrolysis efficiency, but more importantly, effectively releases small molecule active peptides with immunomodulatory functions, with a yield that is more than 25% higher than that of single protease treatment.

[0014] Second, the present invention uses mannan oligosaccharide and chitosan to encapsulate glycopeptide complexes through electrostatic complexation. The resulting microcapsules have obvious pH response characteristics. In the acidic environment of the stomach, they can effectively protect immune active ingredients from damage and ensure that more than 80% of the active ingredients can reach the intestinal site for targeted release, which greatly improves the bioavailability of functional ingredients.

[0015] Third, this invention innovatively co-ferments the encapsulated microcapsules with Clostridium butyricum and Pediococcus lactis. This unique process not only effectively improves the flavor of the product and masks the unpleasant odor of insect protein, but more importantly, it produces abundant short-chain fatty acids and bacteriocins through the metabolic action of probiotics, achieving a dual synergistic function of immune regulation and intestinal microecological regulation. Detailed Implementation

[0016] To enable those skilled in the art to understand the features and effects of this application, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art in this application, and in case of conflict, the definitions in this specification shall prevail.

[0017] The present application will be described below with reference to specific embodiments and examples. It should be understood that these specific embodiments and examples are merely illustrative and are not intended to limit the scope or use of the present application.

[0018] Unless otherwise stated, the methods, reagents, and conditions used in the preparation examples, comparative examples, and embodiments described below are conventional methods, reagents, and conditions in the art.

[0019] Unless otherwise specified, in this application, parts by weight represent the relative number of mass parts in the composition, which can be any mass unit, such as, but not limited to, kilograms, grams, etc.

[0020] The specific embodiments are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Unless otherwise specified, the raw materials and reagents used in the examples are commercially available.

[0021] Example 1 A method for preparing dry pet food that can improve a pet's immunity includes the following steps: (1) Preparation of functional complex: 4.5 kg of black soldier fly larvae, 3.5 kg of whole mealworms, and 1.0 kg of Antarctic krill were weighed. The mixed raw materials were crushed by an ultra-micro pulverizer and mixed with 15 kg of deionized water. The mixture was homogenized by a high-shear homogenizer at 60 MPa pressure to form a uniform composite animal protein slurry. The pH of the composite animal protein slurry was adjusted to 6.4 using 1 mol / L NaOH solution. Then, 0.09 kg of composite protease, which was composed of endopeptide (alkaline protease) and exopeptide (complex flavor protease) in a mass ratio of 3.5:1, was added. The mixture was enzymatically hydrolyzed in a 52℃ water bath for 4.5 hours. The degree of protein hydrolysis was measured to be 21% by the trinitrobenzenesulfonic acid method. Subsequently, 0.6 kg of yeast cell wall extract containing β-glucan was added, and the mixture was stirred at 200 rpm at 55℃ for 2.5 hours to allow the enzymatically hydrolyzed peptides to fully combine with β-glucan through glycosylation to form a stable glycopeptide complex.

[0022] (2) Preparation of encapsulated microcapsules: The glycopeptide complex obtained in step (1) was used as the core material. 3.134 kg of mannan oligosaccharide and 1.741 kg of chitosan (90% degree of deacetylation) were dissolved in 117 L of 1% acetic acid solution to prepare a wall material solution. Encapsulation was performed using the sharp-pore-coagulation bath method. The core material and wall material solution were mixed at a mass ratio of 1:3 and then added dropwise into a coagulation bath containing sodium tripolyphosphate to form microcapsules. The microcapsules were collected, washed with deionized water, and then vacuum dried to obtain microcapsules with a particle size of approximately 150 μm.

[0023] (3) Preparation of fermentation complex: Accurately weigh 48.2 kg of deionized water, 1.0 kg of Clostridium butyricum freeze-dried bacterial powder, 1.0 kg of Pediococcus lactis freeze-dried bacterial powder, and 6.5 kg of microcapsules prepared in step (2). Mix the four ingredients evenly and place them in an anaerobic fermenter for co-fermentation at 37°C for 42 hours. Then, mix the fermentation broth with 37.8 kg of porous starch with a pore size range of 8~15 μm, slowly stir and adsorb at 35°C for 1 hour, and then vacuum dry at 45°C until the moisture content is less than 10%. Pulverize and pass through an 80-mesh sieve to obtain the fermentation complex.

[0024] (4) Preparation of dry food matrix: Dry mix according to the following formula: 25 kg chicken powder, 15 kg corn powder, 10 kg oat powder, 2 kg vitamin and mineral premix, 12 kg glycopeptide complex obtained in step (1), and 6 kg fermentation complex obtained in step (3). Put all raw materials into a twin-screw mixer and mix for 15 minutes until uniform. Then condition the mixed powder by injecting steam and hot water to make the material moisture content reach 22% and the temperature reach 85℃. The conditioned material is fed into a twin-screw extruder and low-temperature extrusion is carried out at a die temperature of 88℃. Control the extruder screw speed to 180 rpm and adjust the feeding speed to ensure that the material stays in the extrusion chamber for about 26 seconds.

[0025] (5) Coating the surface of the particles: After cooling the puffed particles obtained in step (4) to below 35°C, they are coated in three layers in a high-efficiency roller coating machine: the first layer (oil layer) is sprayed with 2.1 kg of chicken oil mixture containing vitamin D3 (addition amount is 1500 IU / kg); the second layer (protective layer) is sprayed with 1.4 kg of aqueous solution of pectin and whey protein in a mass ratio of 4.2:1; the third layer (active layer) is sprayed with 0.7 kg of phosphate buffer containing 0.028% transforming growth factor-β2 (TGF-β2).

[0026] (6) Packaging: The coated products are immediately packaged in aluminum-plastic composite vacuum packaging bags, each bag weighing 1.5kg net, and stored in light-proof cardboard boxes.

[0027] Example 2 A method for preparing dry pet food that can improve a pet's immunity includes the following steps: (1) Preparation of functional complex: Weigh 3.0 kg of black soldier fly larvae, 2.0 kg of whole mealworms, and 1.0 kg of Antarctic krill. After crushing the mixed raw materials with an ultra-micro pulverizer, mix with 12 kg of deionized water and homogenize using a high-shear homogenizer at 50 MPa pressure to form a uniform composite animal protein slurry. Adjust the pH of the composite animal protein slurry to 6.0 using 1 mol / L NaOH solution, and then add 0.06 kg of composite protease, which is a mixture of endopeptide (alkaline protease) and exopeptide (composite flavor protease) in a mass ratio of 2:1. Enzymatically hydrolyze in a 50℃ water bath for 5 hours, and the degree of protein hydrolysis is measured to be 18% by the trinitrobenzenesulfonic acid method. Subsequently, add 0.18 kg of yeast cell wall extract containing β-glucan, and stir at 150 rpm at 50℃ for 3 hours to allow the enzymatically hydrolyzed peptides and β-glucan to fully combine through glycosylation reaction to form a stable glycopeptide complex.

[0028] (2) Preparation of encapsulated microcapsules: The glycopeptide complex obtained in step (1) was used as the core material. 1.875 kg of mannan oligosaccharide and 1.875 kg of chitosan (85% degree of deacetylation) were dissolved in 121.3 L of 1% acetic acid solution to prepare a wall material solution. Encapsulation was performed by spray drying. The core material and wall material solution were mixed at a mass ratio of 1:2. The inlet air temperature was controlled at 120℃ and the outlet air temperature at 65℃ to obtain microcapsules with a particle size of approximately 50 μm.

[0029] (3) Preparation of fermentation complex: Accurately weigh 39.7 kg of deionized water, 1.0 kg of Clostridium butyricum freeze-dried bacterial powder, 1.0 kg of Pediococcus lactis freeze-dried bacterial powder, and 5.0 kg of microcapsules prepared in step (2). Mix the four ingredients evenly and place them in an anaerobic fermenter for co-fermentation at 37°C for 24 hours. Then, mix the fermentation broth with 46.7 kg of porous starch with a pore size range of 5~10 μm, slowly stir and adsorb at 30°C for 1.5 hours, and then vacuum dry at 40°C until the moisture content is less than 10%. Pulverize and pass through an 80-mesh sieve to obtain the fermentation complex.

[0030] (4) Preparation of dry food matrix: Dry mix according to the following formula: 20 kg chicken powder, 12 kg corn powder, 8 kg oat powder, 1.5 kg vitamin and mineral premix, 8 kg glycopeptide complex obtained in step (1), and 3 kg fermentation complex obtained in step (3). Put all raw materials into a twin-screw mixer and mix for 15 minutes until uniform. Then condition the mixed powder by injecting steam and hot water to make the material moisture content reach 20% and the temperature reach 80℃. The conditioned material is fed into a twin-screw extruder and low-temperature extrusion is carried out at a die temperature of 85℃. Control the extruder screw speed to 150 rpm and adjust the feeding speed to ensure that the material stays in the extrusion chamber for about 28 seconds.

[0031] (5) Coating the surface of the particles: After cooling the puffed particles obtained in step (4) to below 35°C, they are coated in three layers in a high-efficiency roller coating machine: the first layer (oil layer) is sprayed with 1.05 kg of chicken oil mixture containing vitamin D3 (addition amount is 1000 IU / kg); the second layer (protective layer) is sprayed with 0.79 kg of aqueous solution of pectin and whey protein in a mass ratio of 3:1; the third layer (active layer) is sprayed with 0.42 kg of phosphate buffer containing 0.02% transforming growth factor-β2 (TGF-β2).

[0032] (6) Packaging: The coated products are immediately packaged in aluminum-plastic composite vacuum packaging bags, each bag weighing 1.5kg net, and stored in light-proof cardboard boxes.

[0033] Example 3 A method for preparing dry pet food that can improve a pet's immunity includes the following steps: (1) Preparation of functional complex: 5.0 kg of black soldier fly larvae, 4.0 kg of whole mealworms, and 1.0 kg of Antarctic krill were weighed. The mixed raw materials were crushed by an ultra-micro pulverizer and mixed with 20 kg of deionized water. The mixture was homogenized by a high-shear homogenizer at 70 MPa pressure to form a uniform composite animal protein slurry. The pH of the composite animal protein slurry was adjusted to 7.0 using 1 mol / L NaOH solution. Then, 0.10 kg of composite protease, which was composed of endopeptide (alkaline protease) and exopeptide (composite flavor protease) in a mass ratio of 4:1, was added. The mixture was enzymatically hydrolyzed in a 60℃ water bath for 4 hours. The degree of protein hydrolysis was measured to be 22% by the trinitrobenzenesulfonic acid method. Subsequently, 0.9 kg of yeast cell wall extract containing β-glucan was added, and the mixture was stirred at 250 rpm at 60℃ for 2 hours to allow the enzymatically hydrolyzed peptides to fully combine with β-glucan through glycosylation to form a stable glycopeptide complex.

[0034] (2) Preparation of encapsulated microcapsules: The glycopeptide complex obtained in step (1) was used as the core material. 4.0 kg of mannan oligosaccharide and 2.0 kg of chitosan (95% degree of deacetylation) were dissolved in 114 L of 1% acetic acid solution to prepare a wall material solution. Encapsulation was performed using the sharp-pore-coagulation bath method. The core material and wall material solution were mixed at a mass ratio of 1:4 and then added dropwise into a coagulation bath containing sodium tripolyphosphate to form microcapsules. The microcapsules were collected, washed with deionized water, and then vacuum dried to obtain microcapsules with a particle size of approximately 200 μm.

[0035] (3) Preparation of fermentation complex: Accurately weigh 56.7 kg of deionized water, 1.0 kg of Clostridium butyricum freeze-dried bacterial powder, 1.0 kg of Pediococcus lactis freeze-dried bacterial powder, and 8.0 kg of microcapsules prepared in step (2). Mix the four ingredients evenly and place them in an anaerobic fermenter for co-fermentation at 37°C for 48 hours. Then, mix the fermentation broth with 33.35 kg of porous starch with a pore size range of 15~20 μm, slowly stir and adsorb at 40°C for 0.5 hours, and then vacuum dry at 50°C until the moisture content is less than 10%. Pulverize and pass through an 80-mesh sieve to obtain the fermentation complex.

[0036] (4) Preparation of dry food matrix: Dry mix according to the following formula: 30 kg chicken powder, 18 kg corn powder, 12 kg oat powder, 2.5 kg vitamin and mineral premix, 15 kg glycopeptide complex obtained in step (1), and 8 kg fermentation complex obtained in step (3). Put all raw materials into a twin-screw mixer and mix for 15 minutes until uniform. Then condition the mixed powder by injecting steam and hot water to make the material moisture content reach 25% and the temperature reach 90℃. The conditioned material is fed into a twin-screw extruder and low-temperature extrusion is carried out at a die temperature of 90℃. Control the extruder screw speed to 200 rpm and adjust the feeding speed to ensure that the material stays in the extrusion chamber for about 22 seconds.

[0037] (5) Surface coating of particles: After cooling the puffed particles obtained in step (4) to below 35°C, three layers of coating are carried out in a high-efficiency roller coating machine: the first layer (oil layer) is sprayed with 3.42 kg of chicken oil mixture containing vitamin D3 (addition amount of 2000 IU / kg); the second layer (protective layer) is sprayed with 2.14 kg of aqueous solution of pectin and whey protein in a mass ratio of 5:1; the third layer (active layer) is sprayed with 1.03 kg of phosphate buffer containing 0.03% transforming growth factor-β2 (TGF-β2).

[0038] (6) Packaging: The coated products are immediately packaged in aluminum-plastic composite vacuum packaging bags, each bag weighing 1.5kg net, and stored in light-proof cardboard boxes.

[0039] Comparative Example 1 (Traditional Enzymatic Hydrolysis Process) A method for preparing dry pet food includes the following steps: (1) Preparation of protein hydrolysate: Weigh 4.5 kg of black soldier fly larvae, 3.5 kg of whole mealworms, and 1.0 kg of Antarctic krill. After crushing the mixed raw materials with an ultrafine pulverizer, mix with 15 kg of deionized water and homogenize using a high-shear homogenizer at 60 MPa pressure to form a uniform composite animal protein slurry. Adjust the pH of the composite animal protein slurry to 7.5 using 1 mol / L NaOH solution and perform enzymatic hydrolysis using a single neutral protease. Enzymatic hydrolysis was carried out in a 50℃ water bath for 4 hours. Subsequently, 0.6 kg of ordinary yeast powder was added, and the reaction was stirred at 200 rpm at 55℃ for 2.5 hours.

[0040] (2) Preparation of dry food base: Dry mix according to the following formula: 25 kg chicken powder, 15 kg corn powder, 10 kg oat powder, 6 kg ordinary probiotic powder (containing only Pediococcus lactis), 2 kg vitamin and mineral premix, and 12 kg protein hydrolysate obtained in step (1). Put all raw materials into a twin-screw mixer and mix for 15 minutes until uniform. Then condition the mixed powder by injecting steam and hot water to make the material moisture content reach 22% and the temperature reach 85℃. The conditioned material is sent into a twin-screw extruder and conventionally extruded at a die temperature of 95℃.

[0041] (3) Spraying the surface of the granules: After cooling the puffed granules obtained in step (2) to below 35°C, spray 2.1 kg of chicken fat mixture containing vitamin D3 (addition amount of 1500 IU / kg) in a high-efficiency roller coating machine.

[0042] (4) Packaging: The product is packaged in ordinary plastic bags.

[0043] Comparative Example 2 (Simple Mixing Process) A method for preparing dry pet food includes the following steps: (1) Raw material pretreatment: Weigh 4.5 kg of black soldier fly larvae, 3.5 kg of whole yellow mealworms and 1.0 kg of Antarctic krill, dry them at high temperature and then crush them through an 80-mesh sieve to obtain mixed insect protein powder.

[0044] (2) Preparation of dry food matrix: Dry mix according to the following formula: 25 kg chicken powder, 15 kg corn powder, 10 kg oat powder, 6 kg common prebiotic (fructooligosaccharides), 2 kg vitamin and mineral premix, and 9 kg of mixed insect protein powder obtained in step (1). Put all raw materials into a twin-screw mixer and mix for 15 minutes until uniform. Then condition the mixed powder by injecting steam and hot water to make the material moisture content reach 22% and the temperature reach 85℃. The conditioned material is sent into a twin-screw extruder and conventionally extruded at a die temperature of 95℃.

[0045] (3) Spraying the surface of the particles: After cooling the puffed particles obtained in step (2) to below 35°C, simply spray vitamin D3 oil in a high-efficiency roller coating machine.

[0046] (4) Packaging: The product is packaged in ordinary plastic bags.

[0047] Comparative Example 3 (key steps omitted) A method for preparing dry pet food includes the following steps: (1) Preparation of protein slurry: Weigh 4.5 kg of black soldier fly larvae, 3.5 kg of whole mealworms, and 1.0 kg of Antarctic krill. After crushing the mixed raw materials with an ultra-fine pulverizer, mix with 15 kg of deionized water and homogenize using a high-shear homogenizer at 60 MPa pressure to form a uniform composite animal protein slurry. Add 0.6 kg of yeast cell wall extract directly and stir at 200 rpm at 55°C for 2.5 hours.

[0048] (2) Preparation of dry food base: Dry mix according to the following formula: 25 kg chicken powder, 15 kg corn powder, 10 kg oat powder, 6 kg common butyric acid Clostridium powder, 2 kg vitamin and mineral premix, and 12 kg protein slurry obtained in step (1). Put all raw materials into a twin-screw mixer and mix for 15 minutes until uniform. Then condition the mixed powder by injecting steam and hot water to make the material moisture content reach 22% and the temperature reach 85℃. The conditioned material is sent into a twin-screw extruder and conventionally extruded at a die temperature of 95℃.

[0049] (3) Packaging: The product is packaged in ordinary plastic bags.

[0050] Examples 1-3 were compared with Comparative Examples 1-3 using the following detection methods: 1. Immune marker testing Treg cell proportion: Flow cytometry analysis of CD4+CD25+FoxP3+ cell population in peripheral blood Serum IgE level: Immunoglobulin E concentration detected by ELISA. 2. Intestinal health indicators Fecal butyric acid content: determination of short-chain fatty acid composition by gas chromatography Intestinal barrier function: Detection of serum diamine oxidase activity and tight junction protein expression Microbial diversity: Shannon diversity index calculated by 16S rRNA sequencing 3. Product performance indicators Retention rate of active ingredients: Changes in the content of functional components before and after processing were determined by HPLC. In vitro release rate: kinetics of functional component release determined in a simulated gastrointestinal fluid environment. 4. Palatability evaluation Feed intake rate: The two-basin method is used to test the amount of food pets can freely choose to eat. Sensory evaluation: Professional evaluators quantify and score indicators such as flavor and texture. The test results are shown in the table below: Detection categories detection indicators Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Immune regulation function Treg cell enhancement (%) +26% +20% +28% +8% +5% +7% Changes in IgE levels Stablize Stablize Stablize +15% +20% +18% Gut health indicators Butyric acid content increased (%) +45% +30% +50% +12% +8% +10% Barrier function score (10 points) 8.5 7.8 8.7 5.2 4.8 5.0 Shannon Diversity Index 6.8 6.5 6.9 5.1 4.9 5.0 Product Performance Active ingredient retention rate (%) 92% 85% 94% 45% 38% 42% Gastric juice release rate (%) 25% 29% 22% 68% 75% 72% Intestinal fluid release rate (%) 88% 81% 90% 35% 28% 32% Palatability evaluation Feed intake rate (%) 98% 95% 97% 72% 68% 70% Preference rating (10 points) 9.2 8.8 9.3 6.5 6.0 6.2 Bitter peptide content (mg / g) 0.8 1.2 0.7 5.6 6.8 5.9 Unpleasant odor rating (10 points) 1.5 2.0 1.3 7.8 8.5 8.0 Through a comprehensive comparison of data from the embodiments and comparative examples, it can be clearly seen that the technical solution of the present invention has achieved a significant improvement over traditional processes in all dimensions, demonstrating systematic technical advantages.

[0051] In terms of core functional indicators, this invention demonstrates revolutionary enhancements. Regarding immune regulation, the Treg cell count in the example group increased by 20-28%, which is 4-5 times higher than that in the control group (5-8%). More importantly, it maintained stable IgE levels while achieving immune enhancement, indicating that this invention establishes a balanced immune regulatory mechanism, rather than simple immune stimulation, effectively avoiding the excessive inflammatory response that may be triggered by traditional immune enhancers. Regarding gut health indicators, the butyrate content in the example group increased by 30-50%, far exceeding the 8-12% in the control group. Combined with the significant advantages in barrier function score and gut microbiota diversity index, this demonstrates that this invention achieves systematic reconstruction and optimization of the gut microbiota through a triple technology system of microencapsulation protection, strain synergy, and carrier sustained release.

[0052] In terms of product performance, the technological breakthroughs of this invention are particularly outstanding. The retention rate of active ingredients reaches 85-94%, which is more than twice that of the control group (38-45%). This is due to the triple protective barrier constructed by microencapsulation, low-temperature puffing, and multi-layer coating, which fundamentally solves the technical problem of easy inactivation of functional ingredients during processing and storage. In terms of delivery efficiency, the control group achieved a gastric juice release rate of less than 30% and an intestinal juice release rate of more than 80%, establishing a true targeted delivery system that ensures that more than 80% of the active ingredients can reach the intestinal site of action, and the bioavailability is more than 3 times higher than that of traditional processes.

[0053] Regarding palatability, this invention successfully addresses the long-standing industry dilemma of functional pet foods being "effective but unpalatable to pets." The bitter peptide content in the example group was controlled at an extremely low level of 0.7-1.2 mg / g, a reduction of over 85% compared to the comparative group (5.6-6.8 mg / g). Combined with a significant improvement in unpleasant odor, this resulted in a 95-98% feed intake rate, far exceeding the 68-72% of the comparative group. This demonstrates that the flavor enhancement system constructed through enzymatic optimization, fermentation improvement, and encapsulation isolation can effectively balance the conflict between functionality and palatability.

[0054] From a technological synergy perspective, the three comparative examples represent three existing technological routes in the industry: the traditional enzymatic hydrolysis process in Comparative Example 1, the simple mixing process in Comparative Example 2, and the process that omits key steps in Comparative Example 3. Their limitations precisely highlight the complete value of the technological system of this invention. This invention, through technological innovations in five dimensions—optimized raw material ratios, enzymatic hydrolysis-glycosylation cascade reaction, intelligent delivery-fermentation dual-system synergy, integrated processing-protection processes, and bidirectional regulation of the immune-gut axis—constructs an interconnected and mutually reinforcing technological network, generating a significant synergistic effect. This is a systemic breakthrough that cannot be achieved through single technological improvements.

[0055] In summary, this invention not only surpasses traditional processes by multiples in various individual indicators, but more importantly, it establishes a complete technological ecosystem. From raw material selection to process design, from ingredient protection to functional realization, it forms a replicable, verifiable, and scalable technological paradigm. This systematic technological innovation not only solves the current technical bottlenecks faced by the functional pet food industry, but also provides a new direction and standard reference for the technological progress of the entire industry, possessing significant industry-leading value and promising commercial application prospects.

[0056] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It should not be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a pet dry food for improving immunity of a pet, characterized in that, The method comprises the following steps: (1) preparing a functional complex: compounding black soldier fly larvae, yellow mealworm whole insects and Antarctic krill according to a mass ratio of (3-5):(2-4):1, crushing and mixing with water to form a complex animal protein slurry; adjusting the pH of the complex animal protein slurry to 6.0-7.0, and performing enzymolysis by using a complex protease compounded by endoprotease and exoprotease according to a mass ratio of (2-4):1, and controlling the degree of proteolysis to be between 18-22%; then, adding a yeast cell wall extract containing β-glucan in an amount of 1-3% of the mass of the complex animal protein slurry, and stirring and reacting at 50-60°C to combine the enzymolysis peptide segments with the β-glucan to form a stable glycopeptide complex; (2) preparing an embedded microcapsule: using mannose oligosaccharide and chitosan solution to coat the glycopeptide complex obtained in step (1) into a microcapsule with a particle size of 50-200 μm, and controlling the release rate of the microcapsule to be less than 30% in simulated gastric juice within 2 hours and to be more than 80% in simulated intestinal juice within 4 hours; (3) preparing a fermentation complex: mixing the microcapsule prepared in step (2) with Clostridium butyricum and Pediococcus acidilactici according to a mass ratio of (5-8):1:1, and performing common fermentation at 37°C in an anaerobic environment for 24-48 hours to obtain a fermentation liquor rich in short-chain fatty acids; then, adsorbing the fermentation liquor on porous starch to form a fermentation complex; (4) preparing a dry food base: dry mixing the functional complex prepared in step (1), the fermentation complex prepared in step (3), meat powder, grain base material, and vitamin and mineral premix, wherein the addition amount of the functional complex is 8-15% of the total mass of the dry mixture, and the addition amount of the fermentation complex is 3-8%; and adjusting the mixed powder, and then performing low-temperature extrusion under the condition that the die temperature is 85-90°C; (5) coating the surface of the particles: sequentially spraying an oil layer containing vitamin D3, a protective layer composed of pectin and whey protein, and a solution containing 0.02-0.03% transforming growth factor-β2 (TGF-β2) on the surface of the extruded particles obtained in step (4); (6) packaging the final product by using oxygen-proof and light-proof packaging materials.

2. The method of claim 1, wherein: In step (1), the stable glycopeptide complex has a hydrated particle size distribution in the range of 100-500 nm.

3. The method of claim 1, wherein: In step (2), the mass ratio of the mannose oligosaccharide to chitosan is (1:1)-(2:1), and the encapsulation rate of the microcapsule is not less than 85%.

4. The method of claim 1, wherein: In step (3), the content of butyric acid in the short-chain fatty acids produced in the common fermentation process is not less than 25%.

5. The method of claim 1, wherein: In step (3), the pore size of the porous starch ranges from 5 μm to 20 μm.

6. The method of claim 1, wherein: In step (4), the screw rotation speed of the low-temperature extrusion is 150-200 rpm, and the residence time of the material in the extruder is less than 30 seconds.

7. The method of claim 1, wherein: In step (5), the mass ratio of pectin to whey protein in the protective layer is (3:1)-(5:1).

8. A pet dry food prepared by the method of any one of claims 1-7.

9. The pet dry food of claim 6, wherein: The dry food can improve the immune function of the pet, and the improvement is specifically that the proportion of regulatory T cells (Treg) in peripheral blood of the pet is increased by at least 20% after being continuously fed for 4 weeks.

10. The pet dry food of claim 6, wherein: The dry food can improve the intestinal health of the pet, and the improvement is specifically that the content of butyric acid in feces of the pet is increased by more than 30% after being continuously fed for 4 weeks.