A method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats

Abstract

This invention relates to the field of pet food preparation technology and discloses a method for preparing enzymatically fermented complete pet food that regulates the intestinal microecology of cats. The method includes the following steps: raw material pretreatment, compound enzymatic hydrolysis treatment, fermentation substrate preparation, compound microbial agent fermentation, post-ripening and drying, preparation of functional oil mixture, and probiotic microencapsulation. By performing stepwise compound enzymatic hydrolysis on animal and plant protein sources, large molecular proteins are degraded into small molecular peptides and amino acids, improving the bioavailability of nutrients and desensitizing potential allergens. Subsequently, a specific ratio of compound probiotic fermentation agent is used to perform temperature- and humidity-controlled solid-state fermentation of the substrate containing the enzymatic hydrolysis products, pre-digesting the substrate and improving its flavor. This allows the final product to gently act on the cat's intestines, providing a nutritional and material basis for the establishment of beneficial intestinal flora and the regulation of microecological balance, thereby enhancing the efficacy of the complete pet food in regulating the intestinal microecology.

Description

Technical Field

[0001] This invention relates to the field of pet food preparation technology, specifically to a method for preparing enzymatically fermented complete pet food that regulates the intestinal microecology of cats. Background Technology

[0002] With socio-economic development and changes in people's lifestyles, companion animals have gained increasing importance in human society, and their health issues have attracted growing attention. Simultaneously, pet food research and development has shifted towards nutritional balance and health benefits. Cats, as important members of the companion animal family, often experience weakened immunity and abnormal intestinal function due to factors such as genetics, stress, diet, and infection. Therefore, their immune function and intestinal health issues have unique research value.

[0003] Currently, when preparing functional complete diets aimed at regulating the intestinal microecology of cats, the common approach is to directly add probiotics, prebiotics, and single enzymatic hydrolysates. However, due to the harsh conditions such as high temperature and high pressure during processing, as well as the acidic environment in the stomach, the added active probiotics are easily inactivated, resulting in a reduced proportion of them colonizing the intestines and exerting their effects, thus failing to achieve stable and continuous microecological regulation.

[0004] Therefore, a method for preparing complete cat food by enzymatic fermentation to regulate the intestinal microecology is proposed to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing enzymatically fermented complete diets that regulate the intestinal microecology of cats, solving the problem mentioned in the background art that the added active probiotics are easily inactivated and cannot achieve a stable and continuous microecological regulation effect.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats, the method comprising the following steps: Step 1, raw material pretreatment: sorting, washing and coarsely crushing animal protein sources, plant protein sources and carbohydrate raw materials; Step 2, compound enzymatic hydrolysis: Mix the treated animal protein source and plant protein source to obtain protein raw material, add compound protease and flavor protease for stepwise enzymatic hydrolysis, and inactivate the enzymes after the process to obtain the first enzymatic hydrolysate; Step 3, Fermentation substrate preparation: Mix the treated carbohydrate raw material with the first enzymatic hydrolysate, add prebiotics, vitamins and mineral elements premix, stir evenly to obtain the fermentation substrate; Step 4, compound microbial fermentation: Inoculate the fermentation substrate with compound probiotic fermentation agent and carry out temperature and humidity controlled solid-state fermentation; Step 5, Post-fermentation and drying: The fermented material is post-fermented and then dried at low temperature to obtain the fermentation substrate; Step 6, Preparation of functional oil mixture: Fish oil, medium-chain triglycerides, phospholipids and antioxidants are homogenized and emulsified under inert gas protection to obtain functional oil mixture; Step 7, Probiotic microencapsulation: Dissolve probiotic freeze-dried powder in sodium alginate solution, form gel microspheres by electrostatic dripping, and then solidify and freeze-dry to obtain probiotic microcapsules; Step 8, Finished Product Mixing and Conditioning: Mix the fermentation base, functional oil mixture, probiotic microcapsules, essential amino acids, taurine and catnip powder evenly to obtain the mixed dry material; Step 9, Ultrafine grinding, secondary mixing and extrusion puffing spraying: The mixed dry materials are ultrafinely ground, then homogenized and mixed again to obtain ultrafine powder. The ultrafine powder is then conditioned and extruded into granules by twin screw extrusion. After cooling, palatability enhancers and natural flavoring agents are sprayed on, and finally dried at low temperature to obtain the complete grain.

[0007] Preferably, in step one, the animal protein source is at least two of fresh or frozen chicken, duck, salmon, and cod mixed in any proportion; The plant-based protein source is at least one of peeled peas, chickpeas, and lentils; The carbohydrate raw material is at least two of the following: pregelatinized tapioca starch, oat flour, and dried sweet potato granules, mixed in any proportion.

[0008] Preferably, in step two, the dry matter mass ratio of animal protein source material to plant protein source material is 6-8:2-4. The compound enzymatic hydrolysis treatment includes the following steps: The mixed protein raw materials are placed into an enzymatic hydrolysis tank equipped with heating and stirring functions. Two to three times the total mass of purified water is added, and the mixture is stirred evenly. The pH is adjusted to 6.0-7.0 using food-grade acid and alkali. The temperature is raised to 50-55℃. First, a compound protease is added, with the amount of the compound protease being 0.8%-1.5% of the total dry matter mass of the protein raw materials. Enzymatic hydrolysis is carried out for 2-3 hours at a stirring speed of 200-300 r / min. Then, the pH of the system is adjusted to 7.0-7.5 using food-grade acid and alkali. A flavor protease is added, with the amount of the flavor protease being 0.5%-1.0% of the total dry matter mass of the protein raw materials. Enzymatic hydrolysis continues for 1-2 hours at the same stirring speed. After enzymatic hydrolysis, the temperature of the enzymatic hydrolysis tank is rapidly raised to 85-90℃ and maintained for 10-15 minutes to inactivate the enzyme. Subsequently, the temperature is rapidly cooled to below 30℃ using a plate heat exchanger to obtain the first enzymatic hydrolysate.

[0009] Preferably, in step three, the fermentation substrate is composed of the following raw materials in parts by weight: 40-50 parts of carbohydrate raw material treated in step one, 30-40 parts of the first enzymatic hydrolysate obtained in step two, 5-8 parts of prebiotics, 1-2 parts of vitamin premix, 1-2 parts of mineral element premix, and 10-15 parts of purified water. The prebiotic is at least two of the following: fructooligosaccharides, galactooligosaccharides, and mannan oligosaccharides. When there are two types, their mass ratio is (1-3):(1-3). When there are three types, their mass ratio is (1-3):(1-3):1. The vitamin premix comprises vitamin A 8000-10000 IU / kg, vitamin D3 500-800 IU / kg, vitamin E 50-100 IU / kg, vitamin K3 5-10 mg / kg, vitamin B1 5-10 mg / kg, vitamin B2 10-20 mg / kg, vitamin B6 6-12 mg / kg, vitamin B12 0.02-0.05 mg / kg, niacin 40-80 mg / kg, calcium pantothenate 20-40 mg / kg, folic acid 2-5 mg / kg, biotin 0.2-0.5 mg / kg, and vitamin C 100-200 mg / kg. The mineral element premix comprises 5-10 g / kg of dicalcium phosphate, 2-5 g / kg of calcium carbonate, 1-3 g / kg of sodium chloride, 150-250 mg / kg of ferrous sulfate, 150-250 mg / kg of zinc sulfate, 20-40 mg / kg of manganese sulfate, 15-25 mg / kg of copper sulfate, 1-3 mg / kg of calcium iodate, and 0.3-0.6 mg / kg of sodium selenite, with a calcium-to-phosphorus ratio between (1.1-1.3):1.

[0010] Preferably, in step four, the compound probiotic starter is composed of freeze-dried powders of Lactobacillus plantarum, Lactobacillus acidophilus, Bifidobacterium animalis, Bacillus subtilis, and Saccharomyces cerevisiae in a live bacteria ratio of (3-5):(2-4):(1-3):(1-2):(1-2), with a total live bacteria count of not less than 1.0 × 10⁻⁶. 11 CFU / g; The fermentation process includes the following steps: the compound probiotic fermentation agent is inoculated at a rate of 0.5%-1.5% of the dry matter mass of the fermentation substrate, revitalized in warm water at 30-35℃ for 10-15 minutes, and then evenly sprayed into the fermentation substrate prepared in step three. Then, it is mixed in a mixer at a speed of 60-80 r / min for 5-10 minutes. The evenly mixed material is transferred to a constant temperature and humidity fermentation chamber, spread out to a thickness of 10-15 cm, and fermented for 36-48 hours at a temperature of 35-38℃ and a relative humidity of 80%-85%. During the fermentation period, the material is turned over once every 8-12 hours.

[0011] Preferably, in step five, the post-fermentation and drying include the following steps: after fermentation, the material is transferred to a post-fermentation room and left to mature for 12-24 hours at 25-30℃ and 60%-70% relative humidity; after maturation, the material is sent to a fluidized bed dryer or belt dryer and dried at an inlet air temperature of 50-60℃ and an air velocity of 1.0-2.0m / s until the moisture content of the material drops to 8%-10%, thus obtaining the fermentation substrate. After drying, the fermentation substrate is cooled and temporarily stored in a cool and dry place.

[0012] Preferably, in step six, the functional oil mixture is composed of the following raw materials in parts by weight: 20-30 parts fish oil, 15-25 parts medium-chain triglycerides, 10-15 parts phospholipids, and 0.1-0.3 parts antioxidants. The fish oil is deep-sea fish oil purified by molecular distillation, wherein the total content of EPA and DHA is not less than 30%, the carbon chain length of the medium-chain triglycerides is C8-C10, the phospholipids are soybean phospholipids or lecithin with a purity of not less than 70%, and the antioxidants are at least two of the following: mixed tocopherols, rosemary extract, and ascorbyl palmitate, mixed in any proportion. The preparation method is as follows: In an emulsification tank filled with nitrogen or argon, fish oil, medium-chain triglycerides and phospholipids are added sequentially. The temperature of the emulsification tank is controlled at 40-45℃, and the mixture is stirred at a speed of 500-800 r / min for 10-15 minutes to allow the materials to be initially mixed. Then, an antioxidant is added, the stirring speed is increased to 1500-2000 r / min, and a high-speed shear emulsifier is turned on. High-speed shear emulsification is carried out at a speed of 8000-12000 r / min for 20-30 minutes until the mixture is a uniform milky white emulsion with a particle size D90 of less than 5 μm, thus obtaining the functional oil mixture. The entire process is carried out under inert gas protection.

[0013] Preferably, in step seven, the method for preparing probiotic microcapsule encapsulation includes the following steps: Core material solution preparation: Probiotic freeze-dried powder, skim milk powder, trehalose and sodium ascorbate are mixed evenly in a mass ratio of 5-7:2-4:1 to obtain a mixture. The mixture is slowly added to a sodium alginate solution with a mass concentration of 2%-4% and a temperature of 30-35℃. The amount of sodium alginate solution used is such that the mass concentration of probiotic freeze-dried powder in the final mixed solution is 15%-25%. The mixture is stirred on a magnetic stirrer at a speed of 300-500r / min for 30-60 minutes until it is completely dissolved and mixed evenly to obtain the core material mixture. Electrostatic droplet molding: Using an electrostatic droplet device, under the conditions of voltage 5-10kV and propulsion speed 0.5-1.5mL / min, the core material mixture is dropped dropwise into a calcium chloride solution with a mass concentration of 1%-3% and a temperature of 4-10℃. The droplets form gel microspheres the instant they come into contact with the calcium chloride solution. Freeze-drying: The obtained gel microspheres are spread evenly in a freeze-drying tray and placed in a vacuum freeze dryer. The tray is freeze-dried for 24-36 hours under conditions where the cold trap temperature is below -50℃ and the vacuum degree is below 10Pa. Dry probiotic microcapsules with a particle size of 0.5-1.5mm are obtained, and the survival rate of probiotics inside is not less than 80%.

[0014] Preferably, in step eight, the raw materials of the finished product mixture are composed of the following components by weight: 50-65 parts of the fermentation base obtained in step five, 8-12 parts of the functional oil mixture obtained in step six, 2-5 parts of the probiotic microcapsules obtained in step seven, 1-3 parts of essential amino acids, 0.1-0.3 parts of taurine, 0.05-0.15 parts of catnip powder, and the remainder is the secondary mixed homogenized material after ultrafine grinding in step nine; The essential amino acid is a mixture of lysine hydrochloride, methionine, threonine and tryptophan, wherein the mass ratio of lysine hydrochloride, methionine, threonine and tryptophan is 4-6:2-4:1-2:1.

[0015] Preferably, step nine includes the following specific processes: Ultrafine grinding and secondary mixing: The mixed dry material obtained in step eight is fed into an airflow ultrafine grinder for grinding, and the particle size of the finished powder is controlled to be D90≤50μm. Then the ultrafine powder is transferred into a V-type mixer and mixed at a speed of 10-15r / min for 20-30 minutes. Extrusion puffing and spraying: The ultrafine powder is fed into a conditioner, through which steam and hot water are introduced. Conditioning is carried out at 90-95℃ for 3-5 minutes to achieve a moisture content of 20%-25%. The conditioned material is then fed into a twin-screw extruder. The process parameters are set as follows: Zone 1 temperature 80-90℃, Zone 2 temperature 100-110℃, Zone 3 temperature 110-120℃, Zone 4 temperature 100-110℃, Die temperature 95-105℃, Screw speed 250-350 r / min, feeding speed adjusted according to die orifice diameter, extrusion pressure 3-6 MPa. The extruded strip is cut into granules of a predetermined length by a cutter. After cooling to room temperature, the granules enter a vacuum spraying machine. Under a vacuum of -0.05 to -0.08 MPa, the material is sprayed with a coating made from yeast extract. A liquid palatability enhancer composed of yeast extract, animal liver hydrolysate, and prebiotic syrup is prepared, wherein the mass ratio of yeast extract, animal liver hydrolysate, and prebiotic syrup is (3-5):(2-4):1, and the spraying amount accounts for 1%-2% of the particle mass. Then, a natural flavoring powder encapsulated in microcapsules is sprayed on under normal pressure. This natural flavoring powder is composed of chicken liver powder, fish soluble powder, and brewer's yeast extract in a mass ratio of (4-6):(3-5):(1-3), and the spraying amount accounts for 0.5%-1% of the particle mass. Finally, the particles after two sprayings are placed in a low-temperature drying oven at 45-55℃ and slowly dried for 20-30 minutes until the final moisture content is reduced to 8%-10%, thus obtaining the enzymatically fermented complete diet for regulating the intestinal microecology of cats.

[0016] Compared with existing technologies, this invention provides a method for preparing enzymatically fermented complete diets that regulate the intestinal microecology of cats, which has the following beneficial effects: 1. In this invention, animal and plant protein sources are subjected to stepwise enzymatic hydrolysis to degrade large protein molecules into small peptides and amino acids, thereby improving the bioavailability of nutrients and desensitizing potential allergens. Subsequently, a specific ratio of compound probiotic fermentation agent is used to carry out temperature- and humidity-controlled solid-state fermentation of the substrate containing the hydrolysate. This process not only further generates abundant prebiotics and beneficial metabolites, providing a superior colonization and proliferation environment for subsequently added probiotics, but also pre-digests and improves the flavor of the substrate during the fermentation process itself. This allows the final product to act gently on the cat's intestines, providing a nutritional and material basis for the establishment of beneficial intestinal flora and the regulation of microecological balance, thereby enhancing the efficacy of complete diet in regulating intestinal microecology.

[0017] 2. In this invention, highly active probiotics are prepared into probiotic microcapsules using electrostatic dripping and gel solidification technology, providing a physical barrier for the probiotics to resist gastric acid, bile salts, and adverse environments during processing and storage. The addition of probiotic microcapsules is placed after the high-temperature extrusion puffing process, and integrated with post-mixing and low-temperature spraying technology, thus avoiding damage to the probiotics from high-temperature and high-pressure processing. In addition, the functional oil mixture is homogenized and emulsified under inert gas protection, and combined with the flavor agent spraying technology of microcapsule encapsulation, the oxidative rancidity of unsaturated fatty acids is prevented, jointly ensuring the high activity and stability of the core functional components at the end of processing and during the product's shelf life.

[0018] 3. In this invention, the mixing uniformity and digestibility of materials are improved by compounding and homogenizing the enzymatic hydrolysate, fermentation base, functional oil mixture, probiotic microcapsules, and essential nutrients through ultra-fine grinding. Subsequently, conditioning and twin-screw extrusion puffing are performed to form brittle, easily digestible granules. Finally, vacuum spraying technology is used to uniformly coat the granule surface with palatability-enhancing agents and natural flavorings, which work synergistically with the natural flavoring substances produced during internal fermentation to improve the product's palatability and taste. This comprehensive processing strategy achieves nutritional supply and microecological regulation while ensuring product palatability, satisfying the cat's natural eating instincts. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: A method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats, the method comprising the following steps: Step 1, raw material pretreatment: sorting, washing and coarsely crushing animal protein sources, plant protein sources and carbohydrate raw materials; Step 2, compound enzymatic hydrolysis: Mix the treated animal protein source and plant protein source to obtain protein raw material, add compound protease and flavor protease for stepwise enzymatic hydrolysis, and inactivate the enzymes after the process to obtain the first enzymatic hydrolysate; Step 3, Fermentation substrate preparation: Mix the treated carbohydrate raw material with the first enzymatic hydrolysate, add prebiotics, vitamins and mineral elements premix, stir evenly to obtain the fermentation substrate; Step 4, compound microbial fermentation: Inoculate the fermentation substrate with compound probiotic fermentation agent and carry out temperature and humidity controlled solid-state fermentation; Step 5, Post-fermentation and drying: The fermented material is post-fermented and then dried at low temperature to obtain the fermentation substrate; Step 6, Preparation of functional oil mixture: Fish oil, medium-chain triglycerides, phospholipids and antioxidants are homogenized and emulsified under inert gas protection to obtain functional oil mixture; Step 7, Probiotic microencapsulation: Dissolve probiotic freeze-dried powder in sodium alginate solution, form gel microspheres by electrostatic dripping, and then solidify and freeze-dry to obtain probiotic microcapsules; Step 8, Finished Product Mixing and Conditioning: Mix the fermentation base, functional oil mixture, probiotic microcapsules, essential amino acids, taurine and catnip powder evenly to obtain the mixed dry material; Step 9, Ultrafine grinding, secondary mixing and extrusion puffing spraying: The mixed dry materials are ultrafinely ground, then homogenized and mixed again to obtain ultrafine powder. The ultrafine powder is then conditioned and extruded into granules by twin screw extrusion. After cooling, palatability enhancers and natural flavoring agents are sprayed on, and finally dried at low temperature to obtain complete grain.

[0021] In step one, the animal protein source raw materials are fresh chicken and duck meat. After sorting to remove visible fat and connective tissue, they are washed twice with purified water, drained, and then fed into a meat grinder to be ground into meat particles with a particle size of 3mm. The plant-based protein source is peeled peas. After sorting to remove impurities, they are washed twice with purified water, drained, and then crushed to 20 mesh using a coarse grinder. The carbohydrate raw materials are pregelatinized tapioca starch and oat flour. After sorting to remove impurities, the powder is sieved off by vibrating screens and then set aside.

[0022] In step two, the dry matter mass ratio of animal protein source material to plant protein source material is 6:2. The compound enzymatic hydrolysis process includes the following steps: The mixed protein raw materials are placed into an enzymatic hydrolysis tank equipped with heating and stirring functions. Twice the total mass of purified water is added, and the mixture is stirred until homogeneous. The pH is adjusted to 6.0 with food-grade hydrochloric acid, and the temperature is raised to 50°C. First, a compound protease is added at a concentration of 0.8% of the total dry matter mass of the protein raw materials. Enzymatic hydrolysis is carried out for 3 hours at a stirring speed of 200 rpm. Then, the pH is adjusted to 7.0 with food-grade sodium hydroxide, and a flavor protease is added at a concentration of 0.5% of the total dry matter mass of the protein raw materials. Enzymatic hydrolysis continues for 2 hours at the same stirring speed. After hydrolysis, the temperature of the enzymatic hydrolysis tank is rapidly raised to 85°C and maintained for 10 minutes to inactivate the enzyme. Subsequently, the temperature is rapidly cooled to below 30°C using a plate heat exchanger to obtain the first enzymatic hydrolysate.

[0023] In step three, the fermentation substrate consists of the following raw materials in parts by weight: 40 parts of carbohydrate raw material treated in step one, 30 parts of the first enzymatic hydrolysate obtained in step two, 5 parts of prebiotics, 1 part of vitamin premix, 1 part of mineral element premix, and 10 parts of purified water. Prebiotics are composed of fructooligosaccharides and galactooligosaccharides in a mass ratio of 1:1. The vitamin premix includes vitamin A 8000 IU / kg, vitamin D3 500 IU / kg, vitamin E 50 IU / kg, vitamin K3 5 mg / kg, vitamin B1 5 mg / kg, vitamin B2 10 mg / kg, vitamin B6 6 mg / kg, vitamin B12 0.02 mg / kg, niacin 40 mg / kg, calcium pantothenate 20 mg / kg, folic acid 2 mg / kg, biotin 0.2 mg / kg, and vitamin C 100 mg / kg. The mineral element premix includes 5 g / kg of dicalcium phosphate, 2 g / kg of calcium carbonate, 1 g / kg of sodium chloride, 150 mg / kg of ferrous sulfate, 150 mg / kg of zinc sulfate, 20 mg / kg of manganese sulfate, 15 mg / kg of copper sulfate, 1 mg / kg of calcium iodate, and 0.3 mg / kg of sodium selenite, with a calcium-to-phosphorus ratio of 1.1:1. During preparation, the first enzymatic hydrolysate is mixed with purified water in a stirred tank. Then, carbohydrate raw materials are slowly added while stirring at 100 r / min. After the mixture is uniform, prebiotics, vitamin premix and mineral premix are added in sequence. The stirring speed is increased to 300 r / min and stirred for 20 minutes until the materials are uniformly mixed and there are no dry powder lumps, resulting in a fermentation substrate with a water content of 35%.

[0024] In step four, the compound probiotic starter is composed of freeze-dried powders of Lactobacillus plantarum, Lactobacillus acidophilus, Bifidobacterium animalis, Bacillus subtilis, and Saccharomyces cerevisiae in a live bacteria ratio of 3:2:1:1:1, with a total live bacteria count of not less than 1.0 × 10⁻⁶. 11 CFU / g; The fermentation process includes the following steps: the compound probiotic fermentation agent is inoculated at a rate of 0.5% of the dry matter mass of the fermentation substrate, reactivated in 30℃ warm water for 10 minutes, and then evenly sprayed into the fermentation substrate prepared in step three. Then, it is mixed in a mixer at a speed of 60r / min for 10 minutes. The evenly mixed material is transferred to a constant temperature and humidity fermentation chamber, spread out to a thickness of 10cm, and fermented for 36 hours at a temperature of 35℃ and a relative humidity of 80%. During the fermentation period, the material is turned over once every 8 hours.

[0025] Step 5, post-fermentation and drying, includes the following steps: After fermentation, the material is transferred to the post-fermentation room and left to mature for 12 hours at 25°C and 60% relative humidity; after maturation, the material is sent to a fluidized bed dryer and dried at an inlet air temperature of 50°C and an air velocity of 1.0 m / s until the moisture content of the material drops to 8%, thus obtaining the fermentation substrate. After drying, the fermentation substrate is cooled and temporarily stored in a cool and dry place.

[0026] In step six, the functional oil mixture is composed of the following raw materials in parts by weight: 20 parts fish oil, 15 parts medium-chain triglycerides, 10 parts phospholipids, and 0.1 parts antioxidants. The fish oil is deep-sea fish oil purified by molecular distillation, in which the total content of EPA and DHA is not less than 30%. The carbon chain length of the medium-chain triglycerides is C8. The phospholipids are soybean phospholipids with a purity of not less than 70%. The antioxidants are composed of mixed tocopherols and rosemary extract. The preparation method is as follows: fish oil, medium-chain triglycerides and phospholipids are added sequentially to an emulsification tank filled with nitrogen. The temperature of the emulsification tank is controlled at 40℃, and the mixture is stirred at 500 r / min for 15 minutes to allow the materials to be initially mixed. Then, an antioxidant is added, the stirring speed is increased to 1500 r / min, and a high-speed shear emulsifier is turned on. High-speed shear emulsification is carried out at 8000 r / min for 30 minutes until the mixture is a uniform milky white emulsion with a particle size D90 of less than 5 μm, thus obtaining a functional oil mixture. The entire process is carried out under inert gas protection.

[0027] Step seven, the preparation method of probiotic microencapsulation includes the following steps: Core material solution preparation: Probiotic mixed lyophilized powder, skim milk powder, trehalose and sodium ascorbate are mixed evenly at a mass ratio of 5:2:1 to obtain a mixture. The mixture is slowly added to a sodium alginate solution with a mass concentration of 2% and a temperature of 30°C. The amount of sodium alginate solution used is such that the mass concentration of probiotic lyophilized powder in the final mixed solution is 15%. The mixture is stirred at a speed of 300r / min for 60 minutes on a magnetic stirrer until it is completely dissolved and mixed evenly to obtain the core material mixture. Electrostatic droplet molding: Using an electrostatic droplet device, under the conditions of 5kV voltage and 0.5mL / min feed speed, the core material mixture is dropped dropwise into a calcium chloride solution with a mass concentration of 1% and a temperature of 4℃. The droplets form gel microspheres the instant they come into contact with the calcium chloride solution. Freeze-drying: The obtained gel microspheres were spread evenly in a freeze-drying tray and placed in a vacuum freeze dryer. The tray was freeze-dried for 24 hours under conditions of cold trap temperature below -50℃ and vacuum degree below 10Pa to obtain dried probiotic microcapsules with a particle size of 0.5mm. The survival rate of probiotics inside the capsules was not less than 80%.

[0028] In step eight, the raw materials of the finished product mixture are composed of the following components by weight: 50 parts of the fermentation base obtained in step five, 8 parts of the functional oil mixture obtained in step six, 2 parts of the probiotic microcapsules obtained in step seven, 1 part of essential amino acids, 0.1 parts of taurine, 0.05 parts of catnip powder, and the remainder is the secondary mixed homogenized material after ultra-fine grinding in step nine. The essential amino acids are a mixture of lysine hydrochloride, methionine, threonine and tryptophan, wherein the mass ratio of lysine hydrochloride, methionine, threonine and tryptophan is 4:2:1:1; The mixture is prepared in a twin-shaft paddle mixer. First, the fermentation base material and the remaining material after the secondary mixing of ultra-fine pulverized materials are added and mixed for 3 minutes. Then, under stirring, the functional oil mixture is evenly sprayed through a spray system and mixed for another 5 minutes. Finally, probiotic microcapsules, essential amino acids, taurine and catnip powder are added and mixed for another 8 minutes until the material is completely homogeneous. The coefficient of variation (CV) of the mixing uniformity is ≤5%, and the mixed dry material is obtained.

[0029] Step nine includes the following specific processes: Ultrafine grinding and secondary mixing: The mixed dry material obtained in step eight is fed into an airflow ultrafine grinder for grinding, and the particle size of the finished powder is controlled to be D90≤50μm. Then the ultrafine powder is transferred to a V-type mixer and mixed at a speed of 10r / min for 30 minutes. Extrusion puffing and spraying: The ultrafine powder is fed into a conditioner, where steam and hot water are introduced. Conditioning is performed at 90℃ for 3 minutes to achieve a moisture content of 20%. The conditioned material is then fed into a twin-screw extruder. Process parameters are set as follows: Zone 1 temperature 80℃, Zone 2 temperature 100℃, Zone 3 temperature 110℃, Zone 4 temperature 100℃, die temperature 95℃, screw speed 250 r / min, feeding speed adjusted according to die orifice diameter, extrusion pressure 3 MPa. The extruded strip is cut into granules of a predetermined length by a cutter. After being cooled to room temperature by cold air, the granules enter a vacuum spraying machine. Under a vacuum of -0.05 MPa, the material is sprayed with a coating made from yeast... A liquid palatability enhancer composed of yeast extract, animal liver hydrolysate, and prebiotic syrup, with a mass ratio of 3:2:1, is sprayed onto the pellets at 1% of their mass. Next, a microcapsule-encapsulated natural flavoring powder, composed of chicken liver powder, fish lysate powder, and brewer's yeast extract in a mass ratio of 4:3:1, is sprayed onto the pellets at atmospheric pressure at 0.5% of their mass. Finally, the pellets after the two spraying processes are placed in a low-temperature drying oven at 45°C and slowly dried for 30 minutes until the final moisture content is reduced to 8%, thus obtaining an enzymatically fermented complete diet for regulating the cat's intestinal microecology.

[0030] Example 2: A method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats, the method comprising the following steps: Step 1, raw material pretreatment: sorting, washing and coarsely crushing animal protein sources, plant protein sources and carbohydrate raw materials; Step 2, compound enzymatic hydrolysis: Mix the treated animal protein source and plant protein source to obtain protein raw material, add compound protease and flavor protease for stepwise enzymatic hydrolysis, and inactivate the enzymes after the process to obtain the first enzymatic hydrolysate; Step 3, Fermentation substrate preparation: Mix the treated carbohydrate raw material with the first enzymatic hydrolysate, add prebiotics, vitamins and mineral elements premix, stir evenly to obtain the fermentation substrate; Step 4, compound microbial fermentation: Inoculate the fermentation substrate with compound probiotic fermentation agent and carry out temperature and humidity controlled solid-state fermentation; Step 5, Post-fermentation and drying: The fermented material is post-fermented and then dried at low temperature to obtain the fermentation substrate; Step 6, Preparation of functional oil mixture: Fish oil, medium-chain triglycerides, phospholipids and antioxidants are homogenized and emulsified under inert gas protection to obtain functional oil mixture; Step 7, Probiotic microencapsulation: Dissolve probiotic freeze-dried powder in sodium alginate solution, form gel microspheres by electrostatic dripping, and then solidify and freeze-dry to obtain probiotic microcapsules; Step 8, Finished Product Mixing and Conditioning: Mix the fermentation base, functional oil mixture, probiotic microcapsules, essential amino acids, taurine and catnip powder evenly to obtain the mixed dry material; Step 9, Ultrafine grinding, secondary mixing and extrusion puffing spraying: The mixed dry materials are ultrafinely ground, then homogenized and mixed again to obtain ultrafine powder. The ultrafine powder is then conditioned and extruded into granules by twin screw extrusion. After cooling, palatability enhancers and natural flavoring agents are sprayed on, and finally dried at low temperature to obtain complete grain.

[0031] In step one, the animal protein source is fresh salmon and cod. After sorting and removing visible fat and connective tissue, the meat is washed twice with purified water, drained, and then fed into a meat grinder to be ground into meat particles with a particle size of 4mm. The plant-based protein source is peeled peas. After sorting to remove impurities, they are washed three times with purified water, drained, and then crushed to 30 mesh using a coarse grinder. The carbohydrate raw materials are oat flour and dried sweet potato granules. After sorting to remove impurities, the powder is sieved off using a vibrating screen and then set aside.

[0032] In step two, the dry matter mass ratio of animal protein source raw materials to plant protein source raw materials is 7:3; The compound enzymatic hydrolysis process includes the following steps: The mixed protein raw materials are placed into an enzymatic hydrolysis tank equipped with heating and stirring functions. 2.5 times the total mass of purified water is added, and the mixture is stirred evenly. The pH is adjusted to 6.5 with food-grade citric acid, and the temperature is raised to 53°C. First, a compound protease is added at a concentration of 1.2% of the total dry matter mass of the protein raw materials. Enzymatic hydrolysis is carried out for 2.5 hours at a stirring speed of 250 r / min. Then, the pH of the system is adjusted to 7.2 with food-grade sodium carbonate, and a flavor protease is added at a concentration of 0.7% of the total dry matter mass of the protein raw materials. Enzymatic hydrolysis continues for 1.5 hours at the same stirring speed. After hydrolysis, the temperature of the enzymatic hydrolysis tank is rapidly raised to 88°C and maintained for 12 minutes to inactivate the enzyme. Subsequently, the temperature is rapidly cooled to below 30°C using a plate heat exchanger to obtain the first enzymatic hydrolysate.

[0033] In step three, the fermentation substrate is composed of the following raw materials in parts by weight: 45 parts of carbohydrate raw material treated in step one, 35 parts of the first enzymatic hydrolysate obtained in step two, 7 parts of prebiotics, 1.5 parts of vitamin premix, 1.5 parts of mineral element premix, and 12 parts of purified water. Prebiotics are composed of fructooligosaccharides, galactooligosaccharides and mannan oligosaccharides in a mass ratio of 1:1:1. The vitamin premix includes vitamin A 9000 IU / kg, vitamin D3 700 IU / kg, vitamin E 70 IU / kg, vitamin K3 7 mg / kg, vitamin B1 7 mg / kg, vitamin B2 15 mg / kg, vitamin B6 9 mg / kg, vitamin B12 0.03 mg / kg, niacin 60 mg / kg, calcium pantothenate 30 mg / kg, folic acid 3 mg / kg, biotin 0.4 mg / kg, and vitamin C 150 mg / kg. The mineral element premix includes 7 g / kg of dicalcium phosphate, 3 g / kg of calcium carbonate, 2 g / kg of sodium chloride, 200 mg / kg of ferrous sulfate, 200 mg / kg of zinc sulfate, 30 mg / kg of manganese sulfate, 20 mg / kg of copper sulfate, 2 mg / kg of calcium iodate, and 0.4 mg / kg of sodium selenite, with a calcium-to-phosphorus ratio of 1.2:1. During preparation, the first enzymatic hydrolysate is mixed with purified water in a stirred tank. Then, carbohydrate raw materials are slowly added while stirring at a speed of 150 r / min. After the mixture is uniform, prebiotics, vitamin premix and mineral premix are added in sequence. The stirring speed is increased to 350 r / min and stirred for 17 minutes until the materials are uniformly mixed and there are no dry powder lumps, resulting in a fermentation substrate with a water content of 40%.

[0034] In step four, the compound probiotic starter is composed of freeze-dried powders of Lactobacillus plantarum, Lactobacillus acidophilus, Bifidobacterium animalis, Bacillus subtilis, and Saccharomyces cerevisiae in a live bacteria ratio of 4:3:2:1.5:1.5, with a total live bacteria count of not less than 1.0 × 10⁻⁶. 11 CFU / g; The fermentation process includes the following steps: the compound probiotic fermentation agent is inoculated at 1.0% of the dry matter mass of the fermentation substrate, reactivated in 33°C warm water for 12 minutes, and then evenly sprayed into the fermentation substrate prepared in step three. Then, it is mixed in a mixer at a speed of 70 r / min for 7 minutes. The evenly mixed material is transferred to a constant temperature and humidity fermentation chamber, spread out to a thickness of 12 cm, and fermented for 42 hours at a temperature of 37°C and a relative humidity of 83%. During the fermentation period, the material is turned over once every 10 hours.

[0035] Step 5, post-fermentation and drying, includes the following steps: After fermentation, the material is transferred to the post-fermentation room and left to mature for 18 hours at 27°C and 65% relative humidity; after maturation, the material is sent to a fluidized bed dryer and dried at an inlet air temperature of 55°C and an air velocity of 1.5 m / s until the moisture content of the material drops to 9%, thus obtaining the fermentation substrate. After drying, the fermentation substrate is cooled and temporarily stored in a cool and dry place.

[0036] In step six, the functional oil mixture is composed of the following raw materials in parts by weight: 25 parts fish oil, 20 parts medium-chain triglycerides, 12 parts phospholipids, and 0.2 parts antioxidants. The fish oil is deep-sea fish oil purified by molecular distillation, in which the total content of EPA and DHA is not less than 30%. The carbon chain length of the medium-chain triglycerides is C9. The phospholipids are soybean phospholipids with a purity of not less than 70%. The antioxidants are composed of mixed tocopherols and ascorbyl palmitate. The preparation method is as follows: fish oil, medium-chain triglycerides and phospholipids are added sequentially to an emulsification tank filled with nitrogen. The temperature of the emulsification tank is controlled at 42℃, and the mixture is stirred at 650 r / min for 12 minutes to allow the materials to be initially mixed. Then, an antioxidant is added, the stirring speed is increased to 1700 r / min, and a high-speed shear emulsifier is turned on. High-speed shear emulsification is carried out at 10000 r / min for 25 minutes until the mixture is a uniform milky white emulsion with a particle size D90 of less than 5 μm, thus obtaining a functional oil mixture. The entire process is carried out under inert gas protection.

[0037] Step seven, the preparation method of probiotic microencapsulation includes the following steps: Core material solution preparation: Probiotic freeze-dried powder, skim milk powder, trehalose and sodium ascorbate are mixed evenly in a mass ratio of 6:3:1 to obtain a mixture. The mixture is slowly added to a sodium alginate solution with a mass concentration of 3% and a temperature of 32°C. The amount of sodium alginate solution used is such that the mass concentration of probiotic freeze-dried powder in the final mixed solution is 20%. The mixture is stirred at a speed of 400 r / min for 45 minutes on a magnetic stirrer until it is completely dissolved and mixed evenly to obtain the core material mixture. Electrostatic droplet molding: Using an electrostatic droplet device, under the conditions of 7kV voltage and 1.0mL / min feed speed, the core material mixture is dropped dropwise into a calcium chloride solution with a mass concentration of 2% and a temperature of 8℃. The droplets form gel microspheres the instant they come into contact with the calcium chloride solution. Freeze-drying: The obtained gel microspheres were spread evenly in a freeze-drying tray and placed in a vacuum freeze dryer. The tray was freeze-dried for 32 hours under conditions of cold trap temperature below -50℃ and vacuum degree below 10Pa to obtain dried probiotic microcapsules with a particle size of 1.0 mm. The survival rate of probiotics inside the capsules was not less than 80%.

[0038] In step eight, the raw materials of the finished product mixture are composed of the following components by weight: 60 parts of the fermentation base obtained in step five, 10 parts of the functional oil mixture obtained in step six, 3 parts of the probiotic microcapsules obtained in step seven, 2 parts of essential amino acids, 0.2 parts of taurine, 0.1 parts of catnip powder, and the remainder is the secondary mixed homogenized material after ultra-fine grinding in step nine. The essential amino acids are a mixture of lysine hydrochloride, methionine, threonine and tryptophan, wherein the mass ratio of lysine hydrochloride, methionine, threonine and tryptophan is 5:3:1.5:1; The mixing is carried out in a twin-shaft paddle mixer. First, the fermentation base material and the remaining material after the secondary mixing of ultra-fine pulverization are added and mixed for 4 minutes. Then, under stirring, the functional oil mixture is evenly sprayed through the spray system and mixed for another 6 minutes. Finally, probiotic microcapsules, essential amino acids, taurine and catnip powder are added and mixed for another 9 minutes until the material is completely uniform. The coefficient of variation (CV) of the mixing uniformity is ≤5%, and the mixed dry material is obtained.

[0039] Step nine includes the following specific processes: Ultrafine grinding and secondary mixing: The mixed dry material obtained in step eight is fed into an airflow ultrafine grinder for grinding, and the particle size of the finished powder is controlled to be D90≤50μm. Then the ultrafine powder is transferred to a V-type mixer and mixed at a speed of 12r / min for 25 minutes. Extrusion puffing and spraying: The ultrafine powder is fed into a conditioner, where steam and hot water are introduced. Conditioning is performed at 92℃ for 4 minutes to achieve a moisture content of 23%. The conditioned material is then fed into a twin-screw extruder. Process parameters are set as follows: Zone 1 temperature 85℃, Zone 2 temperature 105℃, Zone 3 temperature 115℃, Zone 4 temperature 105℃, die temperature 100℃, screw speed 300 r / min, feeding speed adjusted according to die orifice diameter, extrusion pressure 4 MPa. The extruded strip is cut into granules of a predetermined length by a cutter. After being cooled to room temperature by cold air, the granules enter a vacuum spraying machine. Under a vacuum of -0.07 MPa, a coating of yeast is applied. A liquid palatability enhancer composed of yeast extract, animal liver hydrolysate, and prebiotic syrup, with a mass ratio of 4:3:1, is sprayed onto the pellets at a rate of 1.5% of the pellet mass. Next, a microcapsule-encapsulated natural flavoring powder, composed of chicken liver powder, fish syrup powder, and brewer's yeast extract in a mass ratio of 5:4:2, is sprayed onto the pellets at atmospheric pressure at a rate of 0.7% of the pellet mass. Finally, the pellets after the two spraying processes are placed in a low-temperature drying oven at 50°C and slowly dried for 25 minutes until the final moisture content is reduced to 9%, thus obtaining an enzymatically fermented complete diet for regulating the cat's intestinal microecology.

[0040] Example 3: A method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats, the method comprising the following steps: Step 1, raw material pretreatment: sorting, washing and coarsely crushing animal protein sources, plant protein sources and carbohydrate raw materials; Step 2, compound enzymatic hydrolysis: Mix the treated animal protein source and plant protein source to obtain protein raw material, add compound protease and flavor protease for stepwise enzymatic hydrolysis, and inactivate the enzymes after the process to obtain the first enzymatic hydrolysate; Step 3, Fermentation substrate preparation: Mix the treated carbohydrate raw material with the first enzymatic hydrolysate, add prebiotics, vitamins and mineral elements premix, stir evenly to obtain the fermentation substrate; Step 4, compound microbial fermentation: Inoculate the fermentation substrate with compound probiotic fermentation agent and carry out temperature and humidity controlled solid-state fermentation; Step 5, Post-fermentation and drying: The fermented material is post-fermented and then dried at low temperature to obtain the fermentation substrate; Step 6, Preparation of functional oil mixture: Fish oil, medium-chain triglycerides, phospholipids and antioxidants are homogenized and emulsified under inert gas protection to obtain functional oil mixture; Step 7, Probiotic microencapsulation: Dissolve probiotic freeze-dried powder in sodium alginate solution, form gel microspheres by electrostatic dripping, and then solidify and freeze-dry to obtain probiotic microcapsules; Step 8, Finished Product Mixing and Conditioning: Mix the fermentation base, functional oil mixture, probiotic microcapsules, essential amino acids, taurine and catnip powder evenly to obtain the mixed dry material; Step 9, Ultrafine grinding, secondary mixing and extrusion puffing spraying: The mixed dry materials are ultrafinely ground, then homogenized and mixed again to obtain ultrafine powder. The ultrafine powder is then conditioned and extruded into granules by twin screw extrusion. After cooling, palatability enhancers and natural flavoring agents are sprayed on, and finally dried at low temperature to obtain complete grain.

[0041] In step one, the animal protein source is fresh chicken and salmon. After sorting to remove visible fat and connective tissue, the meat is washed three times with purified water, drained, and then fed into a meat grinder to be ground into meat particles with a particle size of 5mm. The plant-based protein source is chickpeas. After sorting to remove impurities, they are washed three times with purified water, drained, and then crushed to 40 mesh using a coarse grinder. The carbohydrate raw materials are pregelatinized cassava starch and dried sweet potato granules. After sorting to remove impurities, they are sieved with a vibrating screen to remove dust and are ready for use.

[0042] In step two, the dry matter mass ratio of animal protein source material to plant protein source material is 8:4. The compound enzymatic hydrolysis process includes the following steps: The mixed protein raw materials are placed into an enzymatic hydrolysis tank equipped with heating and stirring functions. Three times the total mass of purified water is added, and the mixture is stirred until homogeneous. The pH is adjusted to 7.0 using food-grade lactic acid, and the temperature is raised to 55°C. First, a compound protease is added at a concentration of 1.5% of the total dry matter mass of the protein raw materials. Enzymatic hydrolysis is carried out for 2 hours at a stirring speed of 300 rpm. Then, the pH is adjusted to 7.5 using food-grade sodium bicarbonate. Flavor protease is added at a concentration of 1.0% of the total dry matter mass of the protein raw materials. Enzymatic hydrolysis continues for 1 hour at the same stirring speed. After hydrolysis, the temperature of the enzymatic hydrolysis tank is rapidly increased to 90°C and maintained for 15 minutes to inactivate the enzyme. Subsequently, the temperature is rapidly cooled to below 30°C using a plate heat exchanger to obtain the first enzymatic hydrolysate.

[0043] In step three, the fermentation substrate consists of the following raw materials in parts by weight: 50 parts of carbohydrate raw material treated in step one, 40 parts of the first enzymatic hydrolysate obtained in step two, 8 parts of prebiotics, 2 parts of vitamin premix, 2 parts of mineral element premix, and 15 parts of purified water. Prebiotics are composed of fructooligosaccharides, galactooligosaccharides and mannan oligosaccharides in a mass ratio of 2:2:1. The vitamin premix includes vitamin A 10000 IU / kg, vitamin D3 800 IU / kg, vitamin E 100 IU / kg, vitamin K3 10 mg / kg, vitamin B1 10 mg / kg, vitamin B2 20 mg / kg, vitamin B6 12 mg / kg, vitamin B12 0.05 mg / kg, niacin 80 mg / kg, calcium pantothenate 40 mg / kg, folic acid 5 mg / kg, biotin 0.5 mg / kg, and vitamin C 200 mg / kg. The mineral element premix includes 10 g / kg of dicalcium phosphate, 5 g / kg of calcium carbonate, 3 g / kg of sodium chloride, 250 mg / kg of ferrous sulfate, 250 mg / kg of zinc sulfate, 40 mg / kg of manganese sulfate, 25 mg / kg of copper sulfate, 3 mg / kg of calcium iodate, and 0.6 mg / kg of sodium selenite, with a calcium-to-phosphorus ratio of 1.3:1. During preparation, the first enzymatic hydrolysate is mixed with purified water in a stirred tank. Then, carbohydrate raw materials are slowly added while stirring at a speed of 200 r / min. After the mixture is uniform, prebiotics, vitamin premix and mineral premix are added in sequence. The stirring speed is increased to 400 r / min and stirred for 15 minutes until the materials are uniformly mixed and there are no dry powder lumps, resulting in a fermentation substrate with a water content of 45%.

[0044] In step four, the compound probiotic starter is composed of freeze-dried powders of Lactobacillus plantarum, Lactobacillus acidophilus, Bifidobacterium animalis, Bacillus subtilis, and Saccharomyces cerevisiae in a live bacteria ratio of 5:4:3:2:2, with a total live bacteria count of not less than 1.0 × 10⁻⁶. 11 CFU / g; The fermentation process includes the following steps: the compound probiotic fermentation agent is inoculated at 1.5% of the dry matter mass of the fermentation substrate, reactivated in 35℃ warm water for 15 minutes, and then evenly sprayed into the fermentation substrate prepared in step three. Then, it is mixed in a mixer at a speed of 80r / min for 5 minutes. The evenly mixed material is transferred to a constant temperature and humidity fermentation chamber, spread out to a thickness of 15cm, and fermented for 48 hours at a temperature of 38℃ and a relative humidity of 85%. During the fermentation period, the material is turned over once every 12 hours.

[0045] Step 5, post-fermentation and drying, includes the following steps: After fermentation, the material is transferred to the post-fermentation room and left to mature for 24 hours at 30°C and 70% relative humidity; after maturation, the material is sent to a fluidized bed dryer and dried at an inlet air temperature of 60°C and an air velocity of 2.0 m / s until the moisture content of the material drops to 10%, thus obtaining the fermentation substrate. After drying, the fermentation substrate is cooled and temporarily stored in a cool and dry place.

[0046] In step six, the functional oil mixture is composed of the following raw materials in parts by weight: 30 parts fish oil, 25 parts medium-chain triglycerides, 15 parts phospholipids, and 0.3 parts antioxidants. The fish oil is deep-sea fish oil purified by molecular distillation, in which the total content of EPA and DHA is not less than 30%. The carbon chain length of the medium-chain triglycerides is C10. The phospholipids are soybean phospholipids with a purity of not less than 70%. The antioxidants are composed of mixed tocopherols and rosemary extract. The preparation method is as follows: fish oil, medium-chain triglycerides and phospholipids are added sequentially to an emulsification tank filled with nitrogen. The temperature of the emulsification tank is controlled at 45℃, and the mixture is stirred at 800 r / min for 10 minutes to allow the materials to be initially mixed. Then, an antioxidant is added, the stirring speed is increased to 2000 r / min, and a high-speed shear emulsifier is turned on. The mixture is sheared at 12000 r / min for 20 minutes until the mixture is a uniform milky white emulsion with a particle size D90 of less than 5 μm, thus obtaining a functional oil mixture. The entire process is carried out under inert gas protection.

[0047] Step seven, the preparation method of probiotic microencapsulation includes the following steps: Core material solution preparation: Probiotic mixed lyophilized powder, skim milk powder, trehalose and sodium ascorbate were mixed evenly in a mass ratio of 7:4:1 to obtain a mixture. The mixture was slowly added to a sodium alginate solution with a mass concentration of 4% and a temperature of 35°C. The amount of sodium alginate solution was such that the mass concentration of probiotic lyophilized powder in the final mixed solution was 25%. The mixture was stirred at 500 r / min on a magnetic stirrer for 30 minutes until it was completely dissolved and mixed evenly to obtain the core material mixture. Electrostatic droplet molding: Using an electrostatic droplet device, under the conditions of 10kV voltage and 1.5mL / min feed speed, the core material mixture is dropped dropwise into a calcium chloride solution with a mass concentration of 3% and a temperature of 10℃. The droplets form gel microspheres the instant they come into contact with the calcium chloride solution. Freeze-drying: The obtained gel microspheres were spread evenly in a freeze-drying tray and placed in a vacuum freeze dryer. The tray was freeze-dried for 36 hours under conditions of cold trap temperature below -50℃ and vacuum degree below 10Pa to obtain dried probiotic microcapsules with a particle size of 1.5mm. The survival rate of probiotics inside the capsules was not less than 80%.

[0048] In step eight, the raw materials of the finished product mixture are composed of the following components by weight: 65 parts of the fermentation base obtained in step five, 12 parts of the functional oil mixture obtained in step six, 5 parts of the probiotic microcapsules obtained in step seven, 3 parts of essential amino acids, 0.3 parts of taurine, 0.15 parts of catnip powder, and the remainder is the secondary mixed homogenized material after ultra-fine grinding in step nine. The essential amino acids are a mixture of lysine hydrochloride, methionine, threonine and tryptophan, wherein the mass ratio of lysine hydrochloride, methionine, threonine and tryptophan is 6:4:2:1. The mixing is carried out in a twin-shaft paddle mixer. First, the fermentation base material and the remaining material after the secondary mixing of ultra-fine pulverization are added and mixed for 5 minutes. Then, under stirring, the functional oil mixture is evenly sprayed through the spray system and mixed for another 8 minutes. Finally, probiotic microcapsules, essential amino acids, taurine and catnip powder are added and mixed for another 10 minutes until the material is completely uniform. The coefficient of variation (CV) of the mixing uniformity is ≤5%, and the mixed dry material is obtained.

[0049] Step nine includes the following specific processes: Ultrafine grinding and secondary mixing: The mixed dry material obtained in step eight is fed into an airflow ultrafine grinder for grinding, and the particle size of the finished powder is controlled to be D90≤50μm. Then the ultrafine powder is transferred into a V-type mixer and mixed at a speed of 15r / min for 20 minutes. Extrusion Extrusion and Spraying: The ultrafine powder is fed into a conditioner, where steam and hot water are introduced. Conditioning is performed at 95℃ for 5 minutes to achieve a moisture content of 25%. The conditioned material is then fed into a twin-screw extruder. Process parameters are set as follows: Zone 1 temperature 90℃, Zone 2 temperature 110℃, Zone 3 temperature 120℃, Zone 4 temperature 110℃, Die temperature 105℃, Screw speed 350 r / min, feeding speed adjusted according to die orifice diameter, extrusion pressure 6 MPa. The extruded strip is cut into granules of a predetermined length by a cutter. After being cooled to room temperature by cold air, the granules enter a vacuum sprayer. Under a vacuum of -0.08 MPa, the material is sprayed... A liquid palatability enhancer composed of yeast extract, animal liver hydrolysate, and prebiotic syrup, with a mass ratio of 5:4:1, is sprayed onto the pellets at a rate of 2% of the pellet mass. Next, a microcapsule-encapsulated natural flavoring powder, comprising 1% of the pellet mass, is sprayed onto the pellets under normal pressure. This natural flavoring powder is a compound of chicken liver powder, fish syrup powder, and brewer's yeast extract in a mass ratio of 6:5:3. Finally, the pellets after both spraying processes are placed in a low-temperature drying oven at 55°C and slowly dried for 20 minutes until the final moisture content is reduced to 10%, thus obtaining an enzymatically fermented complete diet for regulating the cat's intestinal microecology.

[0050] Comparative Example 1: The difference between this comparative example and Example 1 is that no animal protease and plant protease were added for complex enzymatic hydrolysis in this comparative example, but otherwise it is the same as Example 1.

[0051] Comparative Example 2 differs from Example 1 in that: this comparative example does not use solid-state fermentation process, but directly mixes the mixed dry materials with the compound probiotic fermentation agent by simple stirring. The rest is the same as Example 1.

[0052] Comparative Example 3 differs from Example 1 in that: Bifidobacterium animalis and Lactobacillus acidophilus were not microencapsulated in this comparative example, but were added directly in the form of bacterial powder. All other aspects are the same as in Example 1.

[0053] Comparative Example 4 differs from Example 1 in that the extruded and expanded particles were not cooled and were directly sprayed. Otherwise, they are the same as in Example 1.

[0054] The performance of the enzymatically fermented complete diets for regulating cat gut microbiota prepared in Examples 1-3 and Comparative Examples 1-4 was tested. The test items and methods are as follows: Starch digestibility test: 10g of dried complete grain sample was weighed and 0.2g / L of α-amylase solution was added. The enzymatic hydrolysis reaction was carried out in a constant temperature water bath at 40℃ and 120r / min for 30min. The starch digestibility was calculated by measuring the change in reducing sugar content before and after the reaction. To test the effect of gut microbiota regulation, healthy cats weighing 4kg and 10 months old were selected for a four-week feeding trial. Each cat was fed 50g per day, and fecal samples were collected at the end of each week to extract intestinal contents. High-throughput sequencing technology was used to analyze the diversity and abundance changes of gut microbiota structure, and to assess the colonization of Bifidobacterium and Lactobacillus acidophilus and the content of short-chain fatty acids. The probiotic microcapsule survival rate test involved separating and extracting the probiotic microcapsules from the final product, treating them in simulated gastric fluid at pH 1.8 at a constant temperature of 37°C for 2 hours, and then transferring them to simulated intestinal fluid at pH 6.8 for another 3 hours of constant temperature shaking treatment at 37°C. The ratio of the number of live bacteria released by the microcapsule rupture to the initial number of bacteria was calculated to evaluate the encapsulation protection effect and survival rate of the microcapsules in the simulated digestive environment. The degree of starch gelatinization in extruded feed pellets was determined using the phenol-sulfuric acid method. 1 g of sample was weighed and placed in a stoppered test tube. 5 mL of 80% ethanol solution was added and shaken to mix. Then, 5 mL of 1% phenol solution and 5 mL of concentrated sulfuric acid were added. The mixture was heated in a boiling water bath for 15 min and then cooled to room temperature. Distilled water was used as a blank control. The absorbance was measured at a wavelength of 490 nm to analyze the influence of processing parameters on pellet maturation and digestibility.

[0055] The test data of the enzymatically fermented complete diets for regulating cat gut microbiota prepared in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below: Comparison and analysis of the data in the table show that the enzymatically fermented complete diet prepared using the processes in Examples 1-3 exhibits superior performance compared to the enzymatically fermented complete diet prepared using the processes in Comparative Examples 1-4. This indicates that by performing stepwise compound enzymatic hydrolysis on animal and plant protein sources, large-molecule proteins are degraded into small-molecule peptides and amino acids, improving the bioavailability of nutrients and desensitizing potential allergens. Subsequently, the substrate containing the enzymatic hydrolysates is fermented in a controlled-temperature and humidity solid-state process using a specific ratio of compound probiotic fermentation agent. This process not only further generates abundant prebiotics and beneficial metabolites, providing an excellent environment for the colonization and proliferation of subsequently added probiotics, but the fermentation process itself also pre-digests and improves the flavor of the substrate, allowing the final product to gently act on the cat's intestines, providing the nutritional and material basis for the establishment of beneficial intestinal flora and the regulation of microecological balance, thereby enhancing the efficacy of the complete diet in regulating the intestinal microecology. By employing electrostatic dripping and gel solidification technology to prepare highly active probiotics into probiotic microcapsules, a physical barrier is provided for the probiotics to resist gastric acid, bile salts, and adverse environments during processing and storage. The addition of probiotic microcapsules is placed after the high-temperature extrusion puffing process, and integrated with post-mixing and low-temperature spraying technology, thus avoiding damage to the probiotics from high-temperature and high-pressure processing. In addition, the functional oil mixture is homogenized and emulsified under inert gas protection, and combined with the flavor agent spraying technology of microcapsule encapsulation, the oxidative rancidity of unsaturated fatty acids is prevented, jointly ensuring the high activity and stability of the core functional ingredients at the end of processing and throughout the product's shelf life. By compounding and homogenizing enzymatic hydrolysate, fermentation substrate, functional oil mixture, probiotic microcapsules, and essential nutrients, the uniformity of material mixing and digestibility are improved. Subsequently, conditioning and twin-screw extrusion puffing create a brittle, easily digestible granule form. Finally, vacuum spraying technology evenly coats the granule surface with palatability-enhancing agents and natural flavorings, which synergistically work with the natural flavor substances produced during internal fermentation to improve the product's palatability and attractiveness. This comprehensive processing strategy achieves nutritional supply and microecological regulation while ensuring palatability, satisfying the cat's natural eating instincts.

[0056] By comparing and analyzing the relevant data in the table, it can be seen that the enzymatically fermented complete diet for regulating cat intestinal microecology prepared by the method of the present invention not only has a high starch digestibility, excellent intestinal microecological regulation effect, and extremely high probiotic microcapsule survival rate, but also has a suitable degree of granule gelatinization. This indicates that the enzymatically fermented complete diet for regulating cat intestinal microecology prepared by the present invention has excellent comprehensive performance.

[0057] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats, characterized in that: The method includes the following steps: Step 1, raw material pretreatment: sorting, washing and coarsely crushing animal protein sources, plant protein sources and carbohydrate raw materials; Step 2, compound enzymatic hydrolysis: Mix the treated animal protein source and plant protein source to obtain protein raw material, add compound protease and flavor protease for stepwise enzymatic hydrolysis, and inactivate the enzymes after the process to obtain the first enzymatic hydrolysate; Step 3, Fermentation substrate preparation: Mix the treated carbohydrate raw material with the first enzymatic hydrolysate, add prebiotics, vitamins and mineral elements premix, stir evenly to obtain the fermentation substrate; Step 4, compound microbial fermentation: Inoculate the fermentation substrate with compound probiotic fermentation agent and carry out temperature and humidity controlled solid-state fermentation; Step 5, Post-fermentation and drying: The fermented material is post-fermented and then dried at low temperature to obtain the fermentation substrate; Step 6, Preparation of functional oil mixture: Fish oil, medium-chain triglycerides, phospholipids and antioxidants are homogenized and emulsified under inert gas protection to obtain functional oil mixture; Step 7, Probiotic microencapsulation: Dissolve probiotic freeze-dried powder in sodium alginate solution, form gel microspheres by electrostatic dripping, and then solidify and freeze-dry to obtain probiotic microcapsules; Step 8, Finished Product Mixing and Conditioning: Mix the fermentation base, functional oil mixture, probiotic microcapsules, essential amino acids, taurine and catnip powder evenly to obtain the mixed dry material; Step 9, Ultrafine grinding, secondary mixing and extrusion puffing spraying: The mixed dry materials are ultrafinely ground, then homogenized and mixed again to obtain ultrafine powder. The ultrafine powder is then conditioned and extruded into granules by twin screw extrusion. After cooling, palatability enhancers and natural flavoring agents are sprayed on, and finally dried at low temperature to obtain the complete grain.

2. The method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats according to claim 1, characterized in that: In step one, the animal protein source is at least two of the following: fresh or frozen chicken, duck, salmon, and cod, mixed in any proportion. The plant-based protein source is at least one of peeled peas, chickpeas, and lentils; The carbohydrate raw material is at least two of the following: pregelatinized tapioca starch, oat flour, and dried sweet potato granules, mixed in any proportion.

3. The method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats according to claim 1, characterized in that: In step two, the dry matter mass ratio of animal protein source material to plant protein source material is 6-8:2-4. The compound enzymatic hydrolysis treatment includes the following steps: The mixed protein raw materials are placed into an enzymatic hydrolysis tank equipped with heating and stirring functions. Two to three times the total mass of purified water is added, and the mixture is stirred evenly. The pH is adjusted to 6.0-7.0 using food-grade acid and alkali. The temperature is raised to 50-55℃. First, a compound protease is added, with the amount of the compound protease being 0.8%-1.5% of the total dry matter mass of the protein raw materials. Enzymatic hydrolysis is carried out for 2-3 hours at a stirring speed of 200-300 r / min. Then, the pH of the system is adjusted to 7.0-7.5 using food-grade acid and alkali. A flavor protease is added, with the amount of the flavor protease being 0.5%-1.0% of the total dry matter mass of the protein raw materials. Enzymatic hydrolysis continues for 1-2 hours at the same stirring speed. After enzymatic hydrolysis, the temperature of the enzymatic hydrolysis tank is rapidly raised to 85-90℃ and maintained for 10-15 minutes to inactivate the enzyme. Subsequently, the temperature is rapidly cooled to below 30℃ using a plate heat exchanger to obtain the first enzymatic hydrolysate.

4. The method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats according to claim 1, characterized in that: In step three, the fermentation substrate is composed of the following raw materials in parts by weight: 40-50 parts of carbohydrate raw material treated in step one, 30-40 parts of the first enzymatic hydrolysate obtained in step two, 5-8 parts of prebiotics, 1-2 parts of vitamin premix, 1-2 parts of mineral element premix, and 10-15 parts of purified water. The prebiotic is at least two of the following: fructooligosaccharides, galactooligosaccharides, and mannan oligosaccharides. When there are two types, their mass ratio is (1-3):(1-3). When there are three types, their mass ratio is (1-3):(1-3):

1. The vitamin premix comprises vitamin A 8000-10000 IU / kg, vitamin D3 500-800 IU / kg, vitamin E 50-100 IU / kg, vitamin K3 5-10 mg / kg, vitamin B1 5-10 mg / kg, vitamin B2 10-20 mg / kg, vitamin B6 6-12 mg / kg, vitamin B12 0.02-0.05 mg / kg, niacin 40-80 mg / kg, calcium pantothenate 20-40 mg / kg, folic acid 2-5 mg / kg, biotin 0.2-0.5 mg / kg, and vitamin C 100-200 mg / kg. The mineral element premix comprises 5-10 g / kg of dicalcium phosphate, 2-5 g / kg of calcium carbonate, 1-3 g / kg of sodium chloride, 150-250 mg / kg of ferrous sulfate, 150-250 mg / kg of zinc sulfate, 20-40 mg / kg of manganese sulfate, 15-25 mg / kg of copper sulfate, 1-3 mg / kg of calcium iodate, and 0.3-0.6 mg / kg of sodium selenite, with a calcium-to-phosphorus ratio between (1.1-1.3):

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5. The method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats according to claim 1, characterized in that: In step four, the compound probiotic starter is composed of freeze-dried powders of Lactobacillus plantarum, Lactobacillus acidophilus, Bifidobacterium animalis, Bacillus subtilis, and Saccharomyces cerevisiae in a live bacteria ratio of (3-5):(2-4):(1-3):(1-2):(1-2), with a total live bacteria count of not less than 1.0 × 10⁻⁶. 11 CFU / g; The fermentation process includes the following steps: the compound probiotic fermentation agent is inoculated at a rate of 0.5%-1.5% of the dry matter mass of the fermentation substrate, revitalized in warm water at 30-35℃ for 10-15 minutes, and then evenly sprayed into the fermentation substrate prepared in step three. Then, it is mixed in a mixer at a speed of 60-80 r / min for 5-10 minutes. The evenly mixed material is transferred to a constant temperature and humidity fermentation chamber, spread out to a thickness of 10-15 cm, and fermented for 36-48 hours at a temperature of 35-38℃ and a relative humidity of 80%-85%. During the fermentation period, the material is turned over once every 8-12 hours.

6. The method for preparing enzymatically fermented complete diet for regulating feline gut microbiota according to claim 1, characterized in that: In step five, post-ripening and drying The process includes the following steps: After fermentation, the material is transferred to a post-fermentation room and allowed to stand for 12-24 hours at 25-30℃ and 60%-70% relative humidity. After post-fermentation, the material is fed into a fluidized bed dryer or belt dryer and dried at an inlet air temperature of 50-60℃ and an air velocity of 1.0-2.0m / s until the moisture content of the material drops to 8%-10%, thus obtaining the fermentation substrate. After cooling, the dried fermentation substrate is temporarily stored in a cool and dry place.

7. The method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats according to claim 1, characterized in that: In step six, the functional oil mixture is composed of the following raw materials in parts by weight: 20-30 parts fish oil, 15-25 parts medium-chain triglycerides, 10-15 parts phospholipids, and 0.1-0.3 parts antioxidants. The fish oil is deep-sea fish oil purified by molecular distillation, wherein the total content of EPA and DHA is not less than 30%, the carbon chain length of the medium-chain triglycerides is C8-C10, the phospholipids are soybean phospholipids or lecithin with a purity of not less than 70%, and the antioxidants are at least two of the following: mixed tocopherols, rosemary extract, and ascorbyl palmitate, mixed in any proportion. The preparation method is as follows: In an emulsification tank filled with nitrogen or argon, fish oil, medium-chain triglycerides and phospholipids are added sequentially. The temperature of the emulsification tank is controlled at 40-45℃, and the mixture is stirred at a speed of 500-800 r / min for 10-15 minutes to allow the materials to be initially mixed. Then, an antioxidant is added, the stirring speed is increased to 1500-2000 r / min, and a high-speed shear emulsifier is turned on. High-speed shear emulsification is carried out at a speed of 8000-12000 r / min for 20-30 minutes until the mixture is a uniform milky white emulsion with a particle size D90 of less than 5 μm, thus obtaining the functional oil mixture. The entire process is carried out under inert gas protection.

8. The method for preparing enzymatically fermented complete diet for regulating feline gut microbiota according to claim 1, characterized in that: In step seven, the method for preparing probiotic microcapsules includes the following steps: Core material solution preparation: Probiotic freeze-dried powder, skim milk powder, trehalose and sodium ascorbate are mixed evenly in a mass ratio of 5-7:2-4:1 to obtain a mixture. The mixture is slowly added to a sodium alginate solution with a mass concentration of 2%-4% and a temperature of 30-35℃. The amount of sodium alginate solution used is such that the mass concentration of probiotic freeze-dried powder in the final mixed solution is 15%-25%. The mixture is stirred on a magnetic stirrer at a speed of 300-500r / min for 30-60 minutes until it is completely dissolved and mixed evenly to obtain the core material mixture. Electrostatic droplet molding: Using an electrostatic droplet device, under the conditions of voltage 5-10kV and propulsion speed 0.5-1.5mL / min, the core material mixture is dropped dropwise into a calcium chloride solution with a mass concentration of 1%-3% and a temperature of 4-10℃. The droplets form gel microspheres the instant they come into contact with the calcium chloride solution. Freeze-drying: The obtained gel microspheres are spread evenly in a freeze-drying tray and placed in a vacuum freeze dryer. The tray is freeze-dried for 24-36 hours under conditions where the cold trap temperature is below -50℃ and the vacuum degree is below 10Pa. Dry probiotic microcapsules with a particle size of 0.5-1.5mm are obtained, and the survival rate of probiotics inside is not less than 80%.

9. The method for preparing enzymatically fermented complete diet to regulate the intestinal microecology of cats according to claim 1, characterized in that: In step eight, the raw materials of the finished product mixture are composed of the following components by weight: 50-65 parts of the fermentation base obtained in step five, 8-12 parts of the functional oil mixture obtained in step six, 2-5 parts of the probiotic microcapsules obtained in step seven, 1-3 parts of essential amino acids, 0.1-0.3 parts of taurine, 0.05-0.15 parts of catnip powder, and the remainder is the secondary mixed homogenized material after ultrafine grinding in step nine. The essential amino acid is a mixture of lysine hydrochloride, methionine, threonine and tryptophan, wherein the mass ratio of lysine hydrochloride, methionine, threonine and tryptophan is 4-6:2-4:1-2:

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10. The method for preparing enzymatically fermented complete diet for regulating feline gut microbiota according to claim 1, characterized in that: Step nine includes the following specific processes: Ultrafine grinding and secondary mixing: The mixed dry material obtained in step eight is fed into an airflow ultrafine grinder for grinding, and the particle size of the finished powder is controlled to be D90≤50μm. Then the ultrafine powder is transferred into a V-type mixer and mixed at a speed of 10-15r / min for 20-30 minutes. Extrusion puffing and spraying: The ultrafine powder is fed into a conditioner, through which steam and hot water are introduced. Conditioning is carried out at 90-95℃ for 3-5 minutes to achieve a moisture content of 20%-25%. The conditioned material is then fed into a twin-screw extruder. The process parameters are set as follows: Zone 1 temperature 80-90℃, Zone 2 temperature 100-110℃, Zone 3 temperature 110-120℃, Zone 4 temperature 100-110℃, Die temperature 95-105℃, Screw speed 250-350 r / min, feeding speed adjusted according to die orifice diameter, extrusion pressure 3-6 MPa. The extruded strip is cut into granules of a predetermined length by a cutter. After cooling to room temperature, the granules enter a vacuum spraying machine. Under a vacuum of -0.05 to -0.08 MPa, the material is sprayed with a coating made from yeast extract. A liquid palatability enhancer composed of yeast extract, animal liver hydrolysate, and prebiotic syrup is prepared, wherein the mass ratio of yeast extract, animal liver hydrolysate, and prebiotic syrup is (3-5):(2-4):1, and the spraying amount accounts for 1%-2% of the particle mass. Then, a natural flavoring powder encapsulated in microcapsules is sprayed on under normal pressure. This natural flavoring powder is composed of chicken liver powder, fish soluble powder, and brewer's yeast extract in a mass ratio of (4-6):(3-5):(1-3), and the spraying amount accounts for 0.5%-1% of the particle mass. Finally, the particles after two sprayings are placed in a low-temperature drying oven at 45-55℃ and slowly dried for 20-30 minutes until the final moisture content is reduced to 8%-10%, thus obtaining the enzymatically fermented complete diet for regulating the intestinal microecology of cats.

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