A cat food with enhanced antioxidant capacity and its preparation method

Abstract

This invention relates to the field of cat food technology, specifically to a cat food with enhanced antioxidant capacity and its preparation method. A method for preparing a cat food with enhanced antioxidant capacity includes the following steps: preparation of a carboxymethyl chitosan-grafted rosemary extract copolymer, preparation of antioxidant microcapsules, preparation of baked cat food base, and preparation of baked cat food with enhanced antioxidant capacity. This invention uses pea protein isolate-β-glucan as a composite wall material, combined with a vacuum spraying process, to encapsulate multipolar antioxidants through a W / O / W dual emulsion structure, achieving physical isolation and synergistic release, improving antioxidant efficiency and bioavailability. The three-stage baking and vacuum spraying process optimizes the palatability, texture, and shelf life of the cat food, achieving a dual improvement in function and quality. Long-term feeding can delay skin aging, improve coat condition, and achieve a beautifying effect on the coat.

Description

Technical Field

[0001] This invention relates to the field of cat food technology, specifically to a cat food with enhanced antioxidant capacity and its preparation method. Background Technology

[0002] With the booming development of the pet economy, the health of cats, as family companion animals, has received widespread attention. Consumers' demand for cat food has upgraded from basic nutritional supply to high-quality demand that combines safety, functionality and naturalness. Among these demands, enhancing the antioxidant capacity of cats has become one of the core directions of cat food research and development.

[0003] As obligate carnivores, cats have specific nutritional needs due to their physiological structure, particularly a high requirement for polyunsaturated fatty acids (PUFAs) to ensure their bodies receive essential fatty acids. However, PUFAs are highly susceptible to oxidation, leading to lipid peroxidation and the production of toxic substances such as hydroperoxides and malondialdehyde. This not only causes quality deterioration in cat food, such as rancidity, off-odors, and discoloration, but also destroys fat-soluble vitamins and essential fatty acids. Furthermore, when ingested by cats, PUFAs can exacerbate oxidative stress. Oxidative stress refers to the accumulation of reactive oxygen species (ROS) in the body due to excessive production or a weakened antioxidant defense system. This ROS damages cellular nucleic acids, proteins, lipids, and other biomolecules, leading to a range of health problems, including immune system disorders, rough skin and coat, abnormal liver function, and even chronic diseases such as tumors and heart disease, severely impacting a cat's healthy lifespan and quality of life.

[0004] To address these issues, existing technologies typically involve adding antioxidants during cat food preparation to inhibit lipid oxidation, improve food stability, and enhance the cat's antioxidant capacity. Currently, antioxidants used in cat food are mainly divided into two categories: synthetic antioxidants and natural antioxidants. Synthetic antioxidants, such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), are inexpensive and have significant antioxidant effects, and were once widely used in cat food production. However, recent studies have found that long-term ingestion of these synthetic antioxidants by cats may damage liver function, further driving the shift towards natural antioxidants.

[0005] Natural antioxidants have become a research hotspot in the field of cat food antioxidants due to their advantages such as high biocompatibility, good safety, and no potential toxic side effects. Common natural antioxidants include vitamin C, vitamin E, rosemary extract, green tea polyphenols, and lycopene. However, the application of natural antioxidants in cat food still has many shortcomings in the current technology: the antioxidant effect of a single natural antioxidant is limited, making it difficult to meet the antioxidant needs during cat food processing and storage, and it cannot effectively alleviate oxidative stress in cats; some natural antioxidants are easily deactivated during high-temperature pelleting and extrusion processes in cat food, resulting in a significant reduction in their antioxidant efficacy and preventing them from fully exerting their effects; existing preparation processes have not been optimized for the characteristics of natural antioxidants, making it difficult to achieve efficient retention and synergistic effects of antioxidant components, and it is difficult to achieve the dual effect of ensuring the stability of cat food quality and improving the antioxidant capacity of cats; moreover, some products do not fully consider the digestive and absorption characteristics of cats, resulting in low utilization rates of antioxidant components and failing to fully exert their physiological functions.

[0006] Furthermore, with increasingly stringent regulations in the global pet food industry, consumers are demanding "clean label" and "natural and additive-free" cat food. Therefore, it is necessary to develop a cat food and its preparation method that can effectively improve the cat's antioxidant capacity, is highly safe, nutritionally balanced, and ensure stable quality, in order to solve the problems in existing technologies. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a cat food with improved antioxidant capacity and a method for preparing the same.

[0008] This invention provides a method for preparing cat food with enhanced antioxidant capacity, comprising the following steps: S1: Preparation of carboxymethyl chitosan-grafted rosemary extract copolymer; Carboxymethyl chitosan was dissolved in deionized water and then ascorbic acid and rosemary extract were added sequentially. After purging with nitrogen, hydrogen peroxide was added and the reaction was carried out at room temperature under a nitrogen atmosphere. The resulting copolymer was obtained by dialysis and freeze-drying. S2: Preparation of antioxidant microcapsules; Pea protein isolate and beta Dextran was compounded to obtain a complex powder; using VC and taurine as the inner aqueous phase, the complex powder, the copolymer and malt syrup as the outer aqueous phase, and astaxanthin, lutein, VE and medium-chain triglycerides as the oil phase, the mixture was emulsified in two steps and then spray-dried to obtain antioxidant microcapsules. S3: Preparation of baked cat food base; Grind and mix 35-40 parts fresh chicken, 15-20 parts salmon, 10-12 parts cod, 7-9 parts flounder, 6-8 parts mackerel, 6-7 parts tapioca starch, 5-8 parts fresh chicken liver, 2-3 parts freeze-dried chicken floss, 1-2 parts krill powder, 1-2 parts chicken plasma protein powder, 0.5-0.8 parts fish oil, 1-2 parts cellulose, 0.2-0.3 parts evening primrose seed oil, 0.1-0.2 parts chicory root powder, and 0.02-0.03 parts Schizochytrium powder to obtain a basic mixture. Mix the basic mixture with water, mold it, vacuum moist heat cooking, fluidized bed drying, and bake it to obtain baked cat food base. S4: Preparation of baked cat food with enhanced antioxidant capacity; By vacuum-coating the base material of baked cat food with antioxidant microcapsules, a baked cat food with enhanced antioxidant capacity can be obtained.

[0009] As a preferred aspect, the preparation of S1: carboxymethyl chitosan-grafted rosemary extract copolymer specifically includes the following steps: S1.1: Add 0.5-0.8 parts by weight of carboxymethyl chitosan to 50-60 parts by weight of deionized water, and then stir and mix at 300-500 rpm for 20-30 min to obtain a carboxymethyl chitosan solution. S1.2: Add 1.3-1.5 parts by weight of ascorbic acid and 0.5-0.8 parts by weight of rosemary extract to the carboxymethyl chitosan solution, stir and mix at 400-500 rpm, and adjust the pH to 6 to obtain the reaction solution; S1.3: After purging nitrogen gas into the reaction solution for 60-70 min, add 0.3-0.5 parts by weight of 1 mol / L hydrogen peroxide solution, and then react at room temperature under a nitrogen atmosphere for 24-26 h. After the reaction is completed, place the reactants in a dialysis bag with a molecular weight cutoff of 3000 Da and dialyze with deionized water for 72 h, and then freeze-dry to obtain a carboxymethyl chitosan-grafted rosemary extract copolymer.

[0010] As a preferred aspect, S2: the preparation of antioxidant microcapsules specifically includes the following steps: S2.1: Add 10-12 parts by weight of pea protein isolate to 100-120 parts by weight of deionized water, then add 15-20 parts by weight of β-protein. Dextran was stirred and mixed at 500-800 rpm for 4-5 hours at room temperature, followed by sonication in an ice bath for 10-20 minutes. The ultrasonicated mixture was then freeze-dried to obtain the complex powder. S2.2: Under light-protected conditions, add 3-5 parts by weight of vitamin C and 2-3 parts by weight of taurine to 80-100 parts by weight of deionized water and stir until dissolved. Finally, add 1-2 parts by weight of sodium chloride and stir evenly under light-protected conditions to obtain the inner aqueous phase. Add 6-8 parts by weight of the complex powder, 0.5-1 parts by weight of the carboxymethyl chitosan-grafted rosemary extract copolymer, and 2-3 parts by weight of maltose syrup to 100-120 parts by weight of deionized water, then add 0.5-1 parts by weight of sodium chloride and stir at 300-500 rpm for 1-2 hours to obtain the outer aqueous phase. Under light-protected conditions, add 1-2 parts by weight of astaxanthin, 1-2 parts by weight of lutein, 0.5-1 parts by weight of vitamin E, and 3-5 parts by weight of sorbitan monooleate to 100-120 parts by weight of medium-chain triglycerides and stir at 45-50°C for 30-40 minutes to obtain the oil phase. S2.3: Add the inner aqueous phase to the oil phase at a mass ratio of 1:4-5, and then shear and disperse the mixture at a speed of 15000-18000 rpm for 3-5 minutes to obtain the primary emulsion. Add the primary emulsion to the outer aqueous phase at a mass ratio of 1:4-5, and disperse at a speed of 10000-12000 rpm for 2-3 minutes to obtain the composite emulsion. S2.4: The composite emulsion is spray-dried using spray drying technology to obtain antioxidant microcapsules.

[0011] As a preferred aspect, in step S2.4, the parameters for spray drying are: inlet air temperature of 110-120℃, outlet air temperature of 60-65℃, and feed rate controlled at 10-12 mL / min.

[0012] As a preferred aspect, S3: the preparation of baked cat food base specifically includes the following steps: S3.1: By weight, take 35-40 parts fresh chicken, 15-20 parts salmon, 10-12 parts cod, 7-9 parts flounder, 6-8 parts mackerel, 6-7 parts tapioca starch, 5-8 parts fresh chicken liver, 2-3 parts freeze-dried chicken floss, 1-2 parts krill powder, 1-2 parts chicken plasma protein powder, 0.5-0.8 parts fish oil, 1-2 parts cellulose, 0.2-0.3 parts evening primrose seed oil, 0.1-0.2 parts chicory root powder and 0.02-0.03 parts Schizochytrium powder, mix and grind them together. Put the mixed and ground materials into a mixer and mix at 300-400 rpm for 15-20 minutes to obtain the basic mixture. S3.2: The basic mixture is fed into a mold forming machine and extruded into granules. The granule diameter is controlled at 7-8mm and the thickness at 3-3.5mm to obtain green granules. S3.3: Place the raw pellets in a sealed reactor, evacuate to -0.08 to -0.1 MPa, maintain for 20-30 min, introduce saturated water vapor into the reactor, control the relative humidity to 75-85%, maintain the temperature at 50-55℃, maintain for 40-60 min to obtain cooked cat food pellets, place the cooked cat food pellets in a fluidized bed dryer, introduce hot air at 55-60℃, dry for 30-45 min until the pellet moisture content drops to 8-10%, to obtain dried cooked cat food pellets; S3.4: Place the dried and matured cat food pellets in a tunnel oven for baking. After baking, allow them to cool naturally to below 40°C to obtain the baked cat food base.

[0013] As a preferred aspect, step S3.4 employs a three-stage baking process: the first stage is baked at 80-90℃ for 20-25 minutes, the second stage is baked at 100-105℃ for 15-20 minutes, and the third stage is baked at 85-90℃ for 10-15 minutes.

[0014] As a preferred aspect, S4: The preparation of baked cat food with enhanced antioxidant capacity specifically includes the following steps: Place the above-mentioned baked cat food base into a vacuum mixing and coating tank, turn on the vacuum pump to make the vacuum degree inside the tank reach -0.08 to -0.095 MPa, maintain for 10-15 minutes, and while maintaining the vacuum state, evenly spray the antioxidant microcapsule powder onto the surface of the cat food pellets through an airflow spraying device. After spraying, continue to stir for 15-20 minutes while maintaining the vacuum state to obtain baked cat food with improved antioxidant capacity.

[0015] As a preferred aspect, in step S4, the powder spraying flow rate is controlled at 3-5 g / min, the spraying time is 2-3 min, and the stirring speed is maintained at 20-30 rpm during the spraying process.

[0016] The present invention also provides a cat food with enhanced antioxidant capacity, which is prepared by the method described above for preparing a cat food with enhanced antioxidant capacity.

[0017] The present invention has the following advantages: 1. This invention combines pea protein isolate-β This invention, employing a dextran composite wall material and vacuum spraying process, aims to address the technical challenges of high-activity, heat-sensitive antioxidants in traditional cat food, such as easy oxidation and low bioavailability during high-temperature baking and long-term storage. The invention utilizes a W / O / W dual emulsion structure to encapsulate a combination of strongly hydrophilic and strongly lipophilic antioxidant active ingredients within the same microcapsule, creating a multi-compartment structure. This structural design physically isolates active ingredients of different polarities within the microcapsule, effectively preventing mutual interference caused by direct contact during storage and processing, and significantly improving the stability of multi-source antioxidant formulations. Based on this structure, after the microcapsules enter the animal's digestive tract, the wall material gradually disintegrates under the action of gastrointestinal fluid, allowing the active components to be rapidly released and forming a synergistic antioxidant network in the gastrointestinal environment: the carboxymethyl chitosan-grafted rosemary extract copolymer in the outer aqueous phase acts as a highly efficient free radical scavenger, preferentially exerting its antioxidant effect in the stomach; simultaneously, vitamin C and taurine in the inner aqueous phase and astaxanthin, lutein, and vitamin E in the oil phase are released synchronously, achieving a "multi-point synergistic, spatiotemporal complementary" antioxidant action mode through the complementarity of water-soluble and fat-soluble antioxidant pathways. This synergistic release mechanism helps improve the utilization efficiency of active ingredients, significantly enhancing the antioxidant capacity of cat food. Long-term feeding can delay skin aging, improve coat condition, and reduce the occurrence of oxidative stress-related diseases.

[0018] 2. This invention places a carboxymethyl chitosan-grafted rosemary extract copolymer in an external aqueous phase. This copolymer covalently bonds rosemary extract to the chitosan backbone through chemical grafting. During spray drying, as water evaporates, the copolymer forms a locally high-concentration region rich in antioxidant functional groups on the surface of the microcapsules and around the internal oil droplets, constituting a continuous and stable "interfacial protective layer." Unlike traditional small-molecule antioxidants that easily diffuse and migrate, this copolymer, due to its high molecular weight characteristics, is confined to the oil-water interface region after microcapsule solidification, achieving directional enrichment of antioxidant functional groups and localized long-lasting effects. During microcapsule spray drying and subsequent storage, this protective layer significantly reduces the interfacial oxidation rate of astaxanthin, lutein, and vitamin E in the oil phase, delaying the oxidation loss of the lipid-soluble antioxidants themselves, thereby ensuring the overall shelf-life stability of the microcapsules as an antioxidant delivery carrier.

[0019] 3. This invention optimizes the processing technology, employing a three-stage baking process of "shaping first, then ripening, and finally color fixing." Compared to traditional high-temperature, long-duration baking, this not only better preserves the natural flavor substances in the base ingredients but also creates a moderately caramelized aroma on the surface of the pellets, significantly improving the palatability of the cat food. Furthermore, this invention utilizes vacuum mixing coating and vacuum roller spraying technology, leveraging negative pressure to fully penetrate and firmly adhere antioxidant microcapsules and a hydrophobic protective layer to the pores and surface of the cat food pellets. This avoids the problems of ingredient detachment and surface oxidation that easily occur with traditional atmospheric pressure spraying methods, ensuring the uniform distribution of functional ingredients on each pellet. Building upon this, this invention also uses a combination of steam ripening and three-stage baking to fully gelatinize starch and moderately denature proteins, creating a crispy exterior and chewy interior texture, which is beneficial for pet dental hygiene and improves digestibility. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the preparation method of the cat food with enhanced antioxidant capacity according to the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this invention.

[0022] Example 1: A method for preparing cat food with enhanced antioxidant capacity, referring to... Figure 1 This includes the following steps: S1: Preparation of carboxymethyl chitosan-grafted rosemary extract copolymer S1.1: Add 0.5 parts by weight of carboxymethyl chitosan to 50 parts by weight of deionized water, and then stir and mix at 300 rpm for 20 min to obtain a carboxymethyl chitosan solution. S1.2: Add 1.3 parts by weight of ascorbic acid and 0.5 parts by weight of rosemary extract to the carboxymethyl chitosan solution, stir and mix at 400 rpm, and adjust the pH to 6 to obtain the reaction solution; S1.3: After purging nitrogen gas into the reaction solution for 60 min, 0.3 parts by weight of 1 mol / L hydrogen peroxide solution was added. The reaction was then carried out at room temperature under a nitrogen atmosphere for 24 h. After the reaction was completed, the reactants were placed in a dialysis bag with a molecular weight cutoff of 3000 Da and dialyzed with deionized water for 72 h. After that, the mixture was freeze-dried to obtain a carboxymethyl chitosan-grafted rosemary extract copolymer. S2: Preparation of antioxidant microcapsules S2.1: Add 10 parts by weight of pea protein isolate to 100 parts by weight of deionized water, then add 15 parts by weight of β-protein. Dextran was stirred and mixed at 500 rpm for 4 hours at room temperature, then sonicated in an ice bath for 10 minutes. The sonicated mixture was then freeze-dried to obtain a complex powder. S2.2: Under light-protected conditions, 3 parts by weight of vitamin C and 2 parts by weight of taurine were added to 80 parts by weight of deionized water and stirred until dissolved. Finally, 1 part by weight of sodium chloride was added and stirred evenly under light-protected conditions to obtain the inner aqueous phase. 6 parts by weight of the complex powder, 0.5 parts by weight of the carboxymethyl chitosan-grafted rosemary extract copolymer, and 2 parts by weight of maltose syrup were added to 100 parts by weight of deionized water, followed by 0.5 parts by weight of sodium chloride. The mixture was stirred at 300 rpm for 1 hour to obtain the outer aqueous phase. Under light-protected conditions, 1 part by weight of astaxanthin, 1 part by weight of lutein, 0.5 parts by weight of vitamin E, and 3 parts by weight of sorbitan monooleate were added to 100 parts by weight of medium-chain triglycerides. The mixture was then stirred at 45°C for 30 minutes to obtain the oil phase. S2.3: Add the inner aqueous phase to the oil phase at a mass ratio of 1:4, and then shear and disperse the mixture at 15000 rpm for 3 min to obtain the primary emulsion. Add the primary emulsion to the outer aqueous phase at a mass ratio of 1:4, and disperse at 10000 rpm for 2 min to obtain the composite emulsion. S2.4: The composite emulsion was spray-dried using spray drying technology. The spray drying parameters were: inlet air temperature of 110℃, outlet air temperature of 60℃, and feed rate controlled at 10mL / min to obtain antioxidant microcapsules. S3: Preparation of Baked Cat Food Base S3.1: By weight, take 35 parts fresh chicken, 15 parts salmon, 10 parts cod, 7 parts flounder, 6 parts mackerel, 6 parts tapioca starch, 5 parts fresh chicken liver, 2 parts freeze-dried chicken floss, 1 part krill powder, 1 part chicken plasma protein powder, 0.5 parts fish oil, 1 part cellulose, 0.2 parts evening primrose seed oil, 0.1 parts chicory root powder and 0.02 parts Schizochytrium powder, mix and grind them together. Put the mixed and ground materials into a mixer and mix at 300 rpm for 15 minutes to obtain the basic mixture. S3.2: The basic mixture is fed into a mold forming machine and extruded into granules. The granule diameter is controlled at 7mm and the thickness at 3mm to obtain green granules. S3.3: Place the raw pellets in a sealed reactor, evacuate to -0.08MPa and maintain for 20 minutes. Introduce saturated water vapor into the reactor, control the relative humidity at 75%, maintain the temperature at 50℃ and maintain for 40 minutes to obtain cooked cat food pellets. Place the cooked cat food pellets in a fluidized bed dryer, introduce 55℃ hot air and dry for 30 minutes until the pellet moisture content drops to 8% to obtain dried cooked cat food pellets. S3.4: Place the dried and cooked cat food pellets in a tunnel oven and use a three-stage baking process: the first stage is baked at 80℃ for 20 minutes, the second stage is baked at 100℃ for 15 minutes, and the third stage is baked at 85℃ for 10 minutes. After baking, let it cool naturally to below 40℃ to obtain the baked cat food base. S4: Preparation of Baked Cat Food with Enhanced Antioxidant Capacity Place the above-mentioned baked cat food base into a vacuum mixing and coating tank, turn on the vacuum pump to make the vacuum degree inside the tank reach -0.08MPa, maintain it for 10 minutes, and while maintaining the vacuum state, evenly spray the antioxidant microcapsule powder onto the surface of the cat food pellets through an airflow spraying device, control the spraying flow rate at 3g / min, spray for 2 minutes, and maintain the stirring speed at 20rpm during the spraying process; after the spraying is completed, continue stirring while maintaining the vacuum state for 15 minutes to obtain baked cat food with improved antioxidant capacity.

[0023] Example 2, a method for preparing cat food with enhanced antioxidant capacity, see [link to example]. Figure 1 ,include: S1: Preparation of carboxymethyl chitosan-grafted rosemary extract copolymer S1.1: Add 0.8 parts by weight of carboxymethyl chitosan to 60 parts by weight of deionized water, and then stir and mix at 500 rpm for 30 min to obtain a carboxymethyl chitosan solution. S1.2: Add 1.5 parts by weight of ascorbic acid and 0.8 parts by weight of rosemary extract to the carboxymethyl chitosan solution, stir and mix at 500 rpm, and adjust the pH to 6 to obtain the reaction solution; S1.3: After purging nitrogen gas into the reaction solution for 70 min, 0.5 parts by weight of 1 mol / L hydrogen peroxide solution were added. The reaction was then carried out at room temperature under a nitrogen atmosphere for 26 h. After the reaction was completed, the reactants were placed in a dialysis bag with a molecular weight cutoff of 3000 Da and dialyzed with deionized water for 72 h. After that, the mixture was freeze-dried to obtain a carboxymethyl chitosan-grafted rosemary extract copolymer. S2: Preparation of antioxidant microcapsules S2.1: Add 12 parts by weight of pea protein isolate to 120 parts by weight of deionized water, then add 20 parts by weight of β-protein. Dextran was stirred and mixed at 800 rpm for 5 hours at room temperature, then sonicated in an ice bath for 20 minutes. The sonicated mixture was then freeze-dried to obtain a complex powder. S2.2: Under light-protected conditions, 5 parts by weight of vitamin C and 3 parts by weight of taurine were added to 100 parts by weight of deionized water and stirred until dissolved. Finally, 2 parts by weight of sodium chloride were added and stirred evenly under light-protected conditions to obtain the inner aqueous phase. 8 parts by weight of the complex powder, 1 part by weight of the carboxymethyl chitosan-grafted rosemary extract copolymer, and 3 parts by weight of malt syrup were added to 120 parts by weight of deionized water, followed by 1 part by weight of sodium chloride. The mixture was then stirred at 500 rpm for 2 hours to obtain the outer aqueous phase. Under light-protected conditions, 2 parts by weight of astaxanthin, 2 parts by weight of lutein, 1 part by weight of vitamin E, and 5 parts by weight of sorbitan monooleate were added to 120 parts by weight of medium-chain triglycerides. The mixture was then stirred at 50°C for 40 minutes to obtain the oil phase. S2.3: Add the inner aqueous phase to the oil phase at a mass ratio of 1:5, and then shear and disperse the mixture at 18000 rpm for 5 min to obtain the primary emulsion. Add the primary emulsion to the outer aqueous phase at a mass ratio of 1:5, and disperse at 12000 rpm for 3 min to obtain the composite emulsion. S2.4: The composite emulsion was spray-dried using spray drying technology. The spray drying parameters were: inlet air temperature of 120℃, outlet air temperature of 65℃, and feed rate controlled at 12mL / min to obtain antioxidant microcapsules. S3: Preparation of Baked Cat Food Base S3.1: By weight, take 40 parts fresh chicken, 20 parts salmon, 12 parts cod, 9 parts flounder, 8 parts mackerel, 7 parts tapioca starch, 8 parts fresh chicken liver, 3 parts freeze-dried chicken floss, 2 parts krill powder, 2 parts chicken plasma protein powder, 0.8 parts fish oil, 2 parts cellulose, 0.3 parts evening primrose seed oil, 0.2 parts chicory root powder and 0.03 parts Schizochytrium powder, mix and grind them together. Put the mixed and ground materials into a mixer and mix at 400 rpm for 20 minutes to obtain the basic mixture. S3.2: The basic mixture is fed into a mold forming machine and extruded into granules. The granule diameter is controlled at 8mm and the thickness at 3.5mm to obtain green granules. S3.3: Place the raw pellets in a sealed reactor, evacuate to -0.1MPa and maintain for 30 minutes. Introduce saturated water vapor into the reactor, control the relative humidity to 85%, maintain the temperature at 55℃ and maintain for 60 minutes to obtain cooked cat food pellets. Place the cooked cat food pellets in a fluidized bed dryer, introduce 60℃ hot air and dry for 45 minutes until the moisture content of the pellets drops to 10% to obtain dried cooked cat food pellets. S3.4: Place the dried and cooked cat food pellets in a tunnel oven and use a three-stage baking process: the first stage is baked at 90℃ for 25 minutes, the second stage is baked at 105℃ for 20 minutes, and the third stage is baked at 90℃ for 15 minutes. After baking, let it cool naturally to below 40℃ to obtain the baked cat food base. S4: Preparation of Baked Cat Food with Enhanced Antioxidant Capacity Place the above-mentioned baked cat food base into a vacuum mixing and coating tank, turn on the vacuum pump to make the vacuum degree inside the tank reach -0.095MPa, maintain it for 15 minutes, and while maintaining the vacuum state, evenly spray the antioxidant microcapsule powder onto the surface of the cat food pellets through an airflow spraying device, control the spraying flow rate at 5g / min, spray for 3 minutes, and maintain the stirring speed at 30rpm during the spraying process; after the spraying is completed, continue stirring while maintaining the vacuum state for 20 minutes to obtain baked cat food with improved antioxidant capacity.

[0024] Example 3, a method for preparing cat food with enhanced antioxidant capacity, see [link to example]. Figure 1 ,include: S1: Preparation of carboxymethyl chitosan-grafted rosemary extract copolymer S1.1: Add 0.65 parts by weight of carboxymethyl chitosan to 55 parts by weight of deionized water, and then stir and mix at 400 rpm for 25 min to obtain a carboxymethyl chitosan solution. S1.2: Add 1.4 parts by weight of ascorbic acid and 0.65 parts by weight of rosemary extract to the carboxymethyl chitosan solution, stir and mix at 450 rpm, and adjust the pH to 6 to obtain the reaction solution; S1.3: After purging nitrogen gas into the reaction solution for 65 min, 0.4 parts by weight of 1 mol / L hydrogen peroxide solution was added. The reaction was then carried out at room temperature under a nitrogen atmosphere for 25 h. After the reaction was completed, the reactants were placed in a dialysis bag with a molecular weight cutoff of 3000 Da and dialyzed with deionized water for 72 h. After that, the mixture was freeze-dried to obtain a carboxymethyl chitosan-grafted rosemary extract copolymer. S2: Preparation of antioxidant microcapsules S2.1: Add 11 parts by weight of pea protein isolate to 110 parts by weight of deionized water, then add 17.5 parts by weight of β-protein. Dextran was stirred and mixed at 650 rpm for 4.5 h at room temperature, then sonicated in an ice bath for 15 min. The sonicated mixture was then freeze-dried to obtain a complex powder. S2.2: Under light-protected conditions, 4 parts by weight of vitamin C and 2.5 parts by weight of taurine were added to 90 parts by weight of deionized water and stirred until dissolved. Finally, 1.5 parts by weight of sodium chloride were added and stirred evenly under light-protected conditions to obtain the inner aqueous phase. 7 parts by weight of the complex powder, 0.75 parts by weight of the carboxymethyl chitosan-grafted rosemary extract copolymer, and 2.5 parts by weight of maltose syrup were added to 110 parts by weight of deionized water, followed by 0.75 parts by weight of sodium chloride. The mixture was stirred at 400 rpm for 1.5 h to obtain the outer aqueous phase. Under light-protected conditions, 1.5 parts by weight of astaxanthin, 1.5 parts by weight of lutein, 0.75 parts by weight of vitamin E, and 4 parts by weight of sorbitan monooleate were added to 110 parts by weight of medium-chain triglycerides. The mixture was then stirred at 47.5 °C for 35 min to obtain the oil phase. S2.3: Add the inner aqueous phase to the oil phase at a mass ratio of 1:4.5, and then shear and disperse the mixture at 16500 rpm for 4 min to obtain the primary emulsion. Add the primary emulsion to the outer aqueous phase at a mass ratio of 1:4.5, and disperse at 11000 rpm for 2.5 min to obtain the composite emulsion. S2.4: The composite emulsion was spray-dried using spray drying technology. The spray drying parameters were: inlet air temperature of 115℃, outlet air temperature of 62.5℃, and feed rate controlled at 11mL / min, to obtain antioxidant microcapsules. S3: Preparation of Baked Cat Food Base S3.1: By weight, take 37.5 parts fresh chicken, 17.5 parts salmon, 11 parts cod, 8 parts flounder, 7 parts mackerel, 6.5 parts tapioca starch, 6.5 parts fresh chicken liver, 2.5 parts freeze-dried chicken floss, 1.5 parts krill powder, 1.5 parts chicken plasma protein powder, 0.65 parts fish oil, 1.5 parts cellulose, 0.25 parts evening primrose seed oil, 0.15 parts chicory root powder and 0.025 parts Schizochytrium powder, mix and grind them, put the mixed and ground materials into a mixer and mix at 350 rpm for 17.5 min to obtain the basic mixture; S3.2: The basic mixture is fed into a mold forming machine and extruded into granules. The granule diameter is controlled at 7.5 mm and the thickness at 3.25 mm to obtain green granules. S3.3: Place the raw pellets in a sealed reactor, evacuate to -0.09 MPa and maintain for 25 min, then introduce saturated water vapor into the reactor, control the relative humidity to 80%, maintain the temperature at 52.5℃ and maintain for 50 min to obtain cooked cat food pellets. Place the cooked cat food pellets in a fluidized bed dryer, introduce hot air at 57.5℃ and dry for 37.5 min until the pellet moisture content drops to 9% to obtain dried cooked cat food pellets. S3.4: Place the dried and cooked cat food pellets in a tunnel oven and use a three-stage baking process: the first stage is baked at 85℃ for 22.5 minutes, the second stage is baked at 102.5℃ for 17.5 minutes, and the third stage is baked at 87.5℃ for 12.5 minutes. After baking, let it cool naturally to below 40℃ to obtain the baked cat food base. S4: Preparation of Baked Cat Food with Enhanced Antioxidant Capacity Place the above-mentioned baked cat food base into a vacuum mixing and coating tank, turn on the vacuum pump to achieve a vacuum of -0.09MPa in the tank, maintain this vacuum for 12.5 minutes, and while maintaining the vacuum state, evenly spray the antioxidant microcapsule powder onto the surface of the cat food pellets through an airflow spraying device. Control the spraying flow rate at 4g / min and spray for 2.5 minutes, maintaining a stirring speed of 25rpm during the spraying process. After spraying is completed, continue stirring while maintaining the vacuum state for 17.5 minutes to obtain baked cat food with improved antioxidant capacity.

[0025] Comparative Example 1 differs from Example 1 in that steps S1-S2 and S4 are removed, and step S3.1 is modified as follows: 35 parts by weight of fresh chicken, 15 parts by weight of salmon, 10 parts by weight of cod, 7 parts by weight of flounder, 6 parts by weight of mackerel, 6 parts by weight of tapioca starch, 5 parts by weight of fresh chicken liver, 2 parts by weight of freeze-dried chicken floss, 1 part by weight of krill powder, 1 part by weight of chicken plasma protein powder, 0.5 parts by weight of fish oil, 1 part by weight of cellulose, 0.2 parts by weight of evening primrose seed oil, 0.1 parts by weight of chicory root powder, 0.02 parts by weight of Schizochytrium powder, 3 parts by weight of vitamin C, 2 parts by weight of taurine, 1 part by weight of astaxanthin, 1 part by weight of lutein, and 0.5 parts by weight of vitamin E are added to a mixer and mixed at 300 rpm for 15 minutes to obtain a basic mixture. The remaining steps remain unchanged to prepare a baked cat food with improved antioxidant capacity, which is referred to as Comparative Example 1.

[0026] Comparative Example 2 differs from Example 1 in that the carboxymethyl chitosan-grafted rosemary extract copolymer in steps S1 and S2.2 is removed, while the remaining steps remain unchanged to prepare a baked cat food with improved antioxidant capacity. This is referred to as Comparative Example 2.

[0027] Comparative Example 3 differs from Example 1 in that steps S3.3-S3.4 are removed, and the raw embryo particles in step S3.2 are directly placed in a tunnel oven and baked at 105°C for 45 minutes. The remaining steps remain unchanged to prepare a baked cat food with improved antioxidant capacity, which is referred to as Comparative Example 3.

[0028] Comparative Example 4 differs from Example 1 in that it is a commercially available baked cat food from a certain brand, and is referred to as Comparative Example 4.

[0029] The cat food prepared in Examples 1-3 and Comparative Examples 1-2 was placed in a constant temperature and humidity chamber at 40°C and 75% relative humidity and stored for 6 months. Then, the retention rate of antioxidants (astaxanthin, VC, VE) was determined by high performance liquid chromatography (HPLC). The determination was performed three times and the average value was taken. The results are shown in Table 1.

[0030] Retention rate = (Antioxidant content after 6 months / Initial antioxidant content) × 100%.

[0031] Table 1. Results of antioxidant retention rate determination in Examples 1-3 and Comparative Examples 1-2

[0032] As can be seen from the data in Table 1, the high retention rate of the examples is due to the multi-compartment physical isolation achieved by the W / O / W dual emulsion structure of the present invention, and the "interfacial protective layer" formed at the oil-water interface by the carboxymethyl chitosan-grafted rosemary extract copolymer, which effectively reduces the oxidation rate of lipid-soluble antioxidants.

[0033] In Comparative Example 1, the retention rate of each antioxidant was significantly reduced because the unencapsulated active ingredients were directly exposed in the base material and were easily oxidized and degraded during high-temperature baking and storage.

[0034] In Comparative Example 2, the retention rate of antioxidants also decreased after the absence of carboxymethyl chitosan-grafted rosemary extract copolymer, indicating that the addition of carboxymethyl chitosan-grafted rosemary extract copolymer can delay the oxidative loss of antioxidants themselves.

[0035] Healthy adult cats (weighing 4-5kg, 5 years old, 5 cats per group, 3 meals a day, 80g per meal) were fed the cat food of Examples 1-3, Comparative Examples 1-2 and Comparative Example 4. After 3 months of feeding, 10 professional pet groomers conducted a blind evaluation and scored the shine and smoothness of the fur, and the average value was taken. The specific results are shown in Table 2.

[0036] Blind rating: 0-10 points, the higher the score, the better the hair's shine and smoothness.

[0037] Table 2. Scoring results of Examples 1-3, Comparative Examples 1-2, and Comparative Example 4

[0038] As can be seen from the data in Table 2, the hair shine and smoothness of the examples were significantly better than those of the comparative examples. This is attributed to the antioxidant mechanism of the present invention: the release of VC, taurine, astaxanthin, lutein, and VE forms a synergistic antioxidant network; astaxanthin and lutein are specifically enriched in skin tissue, improving skin elasticity and hair shine. In Comparative Example 1, the antioxidants were largely lost during processing and storage, resulting in low bioavailability and poor long-term feeding effects. Therefore, the hair shine and smoothness were significantly worse. The data from Comparative Example 2 indicate that the lack of preferential free radical scavenging effect of carboxymethyl chitosan-grafted rosemary extract copolymer in the stomach led to a decrease in overall antioxidant efficacy, resulting in poor hair shine and smoothness.

[0039] Equal amounts of cat food from Example 1, Comparative Examples 3 and 4 were placed in cat cages. The first food bowl chosen by each of the 20 cats within 30 minutes and the amount of food consumed were recorded. This test was conducted continuously for 3 days, and the feed intake rate and feed consumption ratio were calculated. Feed intake rate = (Number of cats choosing this cat food for the first time within 30 minutes / Total number of cats tested) × 100%. Feed consumption ratio = (Total feed consumption over 3 days / Total amount of cat food) × 100%. The results are shown in Table 3.

[0040] Table 3. Palatability test results of cat food from Example 1, Comparative Example 3, and Comparative Example 4

[0041] As can be seen from the data in Table 3, the present invention adopts a three-stage baking process of "shaping first, then ripening, and then color fixing". Compared with the traditional long-term baking of Comparative Example 3 and Comparative Example 4, it better preserves the natural flavor substances in the base material, and at the same time forms a moderate caramel aroma on the surface of the particles, which significantly improves palatability.

[0042] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Parts not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A method for preparing cat food with enhanced antioxidant capacity, characterized in that, Includes the following steps: S1: Preparation of carboxymethyl chitosan-grafted rosemary extract copolymer; Carboxymethyl chitosan was dissolved in deionized water and then ascorbic acid and rosemary extract were added sequentially. After purging with nitrogen, hydrogen peroxide was added and the reaction was carried out at room temperature under a nitrogen atmosphere. The resulting product was obtained by dialysis and freeze-drying. S2: Preparation of antioxidant microcapsules; Pea protein isolate and beta A complex powder was obtained by combining dextran; using VC, taurine, deionized water and sodium chloride as the inner aqueous phase, the complex powder, carboxymethyl chitosan-grafted rosemary extract copolymer, malt syrup, deionized water and sodium chloride as the outer aqueous phase, and astaxanthin, lutein, VE, medium-chain triglycerides and sorbitan monooleate as the oil phase, the mixture was emulsified in two steps and then spray-dried to obtain antioxidant microcapsules; S3: Preparation of baked cat food base; Grind and mix 35-40 parts fresh chicken, 15-20 parts salmon, 10-12 parts cod, 7-9 parts flounder, 6-8 parts mackerel, 6-7 parts tapioca starch, 5-8 parts fresh chicken liver, 2-3 parts freeze-dried chicken floss, 1-2 parts krill powder, 1-2 parts chicken plasma protein powder, 0.5-0.8 parts fish oil, 1-2 parts cellulose, 0.2-0.3 parts evening primrose seed oil, 0.1-0.2 parts chicory root powder, and 0.02-0.03 parts Schizochytrium powder to obtain a basic mixture. Mix the basic mixture with water, mold it, vacuum moist heat cooking, fluidized bed drying, and bake it to obtain baked cat food base. S4: Preparation of baked cat food with enhanced antioxidant capacity; By vacuum-coating the base material of baked cat food with antioxidant microcapsules, a baked cat food with enhanced antioxidant capacity can be obtained.

2. The method for preparing cat food with enhanced antioxidant capacity according to claim 1, characterized in that, S1: The preparation of carboxymethyl chitosan-grafted rosemary extract copolymer includes the following steps: S1.1: Add 0.5-0.8 parts by weight of carboxymethyl chitosan to 50-60 parts by weight of deionized water, and then stir and mix at 300-500 rpm for 20-30 min to obtain a carboxymethyl chitosan solution. S1.2: Add 1.3-1.5 parts by weight of ascorbic acid and 0.5-0.8 parts by weight of rosemary extract to the carboxymethyl chitosan solution, stir and mix at 400-500 rpm, and adjust the pH to 6 to obtain the reaction solution; S1.3: After purging nitrogen gas into the reaction solution for 60-70 min, add 0.3-0.5 parts by weight of 1 mol / L hydrogen peroxide solution, and then react at room temperature under a nitrogen atmosphere for 24-26 h. After the reaction is completed, place the reactants in a dialysis bag with a molecular weight cutoff of 3000 Da and dialyze with deionized water for 72 h, and then freeze-dry to obtain a carboxymethyl chitosan-grafted rosemary extract copolymer.

3. The method for preparing cat food with enhanced antioxidant capacity according to claim 1, characterized in that, S2: The preparation of antioxidant microcapsules includes the following steps: S2.1: Add 10-12 parts by weight of pea protein isolate to 100-120 parts by weight of deionized water, then add 15-20 parts by weight of β-protein. Dextran was stirred and mixed at 500-800 rpm for 4-5 hours at room temperature, followed by sonication in an ice bath for 10-20 minutes. The ultrasonicated mixture was then freeze-dried to obtain a complex powder. S2.2: Under light-protected conditions, add 3-5 parts by weight of vitamin C and 2-3 parts by weight of taurine to 80-100 parts by weight of deionized water and stir until dissolved. Finally, add 1-2 parts by weight of sodium chloride and stir evenly under light-protected conditions to obtain the inner aqueous phase. Add 6-8 parts by weight of the complex powder, 0.5-1 parts by weight of the carboxymethyl chitosan-grafted rosemary extract copolymer, and 2-3 parts by weight of maltose syrup to 100-120 parts by weight of deionized water, then add 0.5-1 parts by weight of sodium chloride and stir at 300-500 rpm for 1-2 hours to obtain the outer aqueous phase. Under light-protected conditions, add 1-2 parts by weight of astaxanthin, 1-2 parts by weight of lutein, 0.5-1 parts by weight of vitamin E, and 3-5 parts by weight of sorbitan monooleate to 100-120 parts by weight of medium-chain triglycerides and stir at 45-50°C for 30-40 minutes to obtain the oil phase. S2.3: Add the inner aqueous phase to the oil phase at a mass ratio of 1:4-5, and then shear and disperse the mixture at a speed of 15000-18000 rpm for 3-5 minutes to obtain the primary emulsion. Add the primary emulsion to the outer aqueous phase at a mass ratio of 1:4-5, and disperse at a speed of 10000-12000 rpm for 2-3 minutes to obtain the composite emulsion. S2.4: The composite emulsion is spray-dried using spray drying technology to obtain antioxidant microcapsules.

4. The method for preparing cat food with improved antioxidant capacity according to claim 3, characterized in that, In step S2.4, the parameters for spray drying are: inlet air temperature of 110-120℃, outlet air temperature of 60-65℃, and feed rate controlled at 10-12 mL / min.

5. The method for preparing cat food with enhanced antioxidant capacity according to claim 1, characterized in that, S3: Preparation of baked cat food base, specifically including the following steps: S3.1: By weight, take 35-40 parts fresh chicken, 15-20 parts salmon, 10-12 parts cod, 7-9 parts flounder, 6-8 parts mackerel, 6-7 parts tapioca starch, 5-8 parts fresh chicken liver, 2-3 parts freeze-dried chicken floss, 1-2 parts krill powder, 1-2 parts chicken plasma protein powder, 0.5-0.8 parts fish oil, 1-2 parts cellulose, 0.2-0.3 parts evening primrose seed oil, 0.1-0.2 parts chicory root powder and 0.02-0.03 parts Schizochytrium powder, mix and grind them together. Put the mixed and ground materials into a mixer and mix at 300-400 rpm for 15-20 minutes to obtain the basic mixture. S3.2: The basic mixture is fed into a mold forming machine and extruded into granules. The granule diameter is controlled at 7-8mm and the thickness at 3-3.5mm to obtain green granules. S3.3: Place the raw pellets in a sealed reactor, evacuate to -0.08 to -0.1 MPa, maintain for 20-30 min, introduce saturated water vapor into the reactor, control the relative humidity to 75-85%, maintain the temperature at 50-55℃, maintain for 40-60 min to obtain cooked cat food pellets, place the cooked cat food pellets in a fluidized bed dryer, introduce hot air at 55-60℃, dry for 30-45 min until the pellet moisture content drops to 8-10%, to obtain dried cooked cat food pellets; S3.4: Place the dried and matured cat food pellets in a tunnel oven for baking. After baking, allow them to cool naturally to below 40°C to obtain the baked cat food base.

6. The method for preparing cat food with enhanced antioxidant capacity according to claim 5, characterized in that, Step S3.4 employs a three-stage baking process: the first stage is baked at 80-90℃ for 20-25 minutes, the second stage is baked at 100-105℃ for 15-20 minutes, and the third stage is baked at 85-90℃ for 10-15 minutes.

7. The method for preparing cat food with enhanced antioxidant capacity according to claim 1, characterized in that, S4: The preparation of baked cat food with enhanced antioxidant capacity includes the following steps: Place the above-mentioned baked cat food base into a vacuum mixing and coating tank, turn on the vacuum pump to make the vacuum degree inside the tank reach -0.08 to -0.095 MPa, maintain for 10-15 minutes, and while maintaining the vacuum state, evenly spray the antioxidant microcapsule powder onto the surface of the cat food pellets through an airflow spraying device. After spraying, continue to stir for 15-20 minutes while maintaining the vacuum state to obtain baked cat food with improved antioxidant capacity.

8. The method for preparing cat food with improved antioxidant capacity according to claim 7, characterized in that, In step S4, the powder spraying flow rate is controlled at 3-5 g / min, and the spraying time is 2-3 minutes. During the spraying process, the stirring speed is maintained at 20-30 rpm.

9. A cat food with enhanced antioxidant capacity, characterized in that, It is prepared by the method for preparing cat food with improved antioxidant capacity as described in any one of claims 1-8.

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