Pet anti-oxidation food added with natural plant active ingredients and preparation method of pet anti-oxidation food

Abstract

The invention relates to the technical field of pet food, in particular to pet anti-oxidation food added with natural plant active ingredients and a preparation method of the pet anti-oxidation food, and the pet anti-oxidation food is prepared by adopting the processes of mixing, extrusion puffing, drying and cooling; the preparation method comprises the following steps: forming a compound from curcumin and phospholipid, and then embedding the compound and green tea polyphenol in a hydrogel shell together to form a composite microcapsule; placing the cooled pet food basic particles in a vacuum chamber, spraying chicken oil into the vacuum chamber under the condition that the pressure is lower than 10kPa, keeping for 2-5 minutes, spraying composite microcapsule powder into the vacuum chamber for 5-15 minutes under the condition that the pressure is increased to 30-50kPa again, then stopping vacuumizing, and restoring the normal pressure to obtain the antioxidant food. According to the preparation method disclosed by the invention, the curcumin-phospholipid compound is constructed, a W1 / O / W2 double emulsion technology is utilized, water-soluble green tea polyphenol and fat-soluble curcumin are jointly embedded in one microcapsule, and a freeze-drying process is combined, so that the anti-oxidation effect of pets is improved.

Description

Technical Field

[0001] This invention relates to the technical field of pet food, specifically to a pet antioxidant food with added natural plant active ingredients and its preparation method. Background Technology

[0002] With the rapid growth of pet ownership globally and the popularization of pet health management concepts, the pet food market has exceeded hundreds of billions of US dollars, with functional pet foods (such as antioxidant-rich foods) accounting for an increasing proportion year by year. According to relevant industry reports, the incidence of oxidative stress-related diseases in pets (such as arthritis, immune decline, and intestinal inflammation) is as high as 30%, highlighting the urgent need to develop highly effective and stable natural antioxidant additives. Curcumin (derived from turmeric) and green tea polyphenols (mainly catechin compounds), as plant-derived natural antioxidants, possess powerful free radical scavenging, anti-inflammatory, and immune-enhancing effects, and have been widely recognized as core components of pet nutritional supplements. However, their application in pet food faces multiple challenges, including processing stability, bioavailability, and uniform distribution. This invention aims to solve these problems through innovative microencapsulation and coating processes, maximizing the antioxidant effects for pets.

[0003] Publication No. CN106659230A discloses a pet food containing antioxidants and its preparation method, which includes mixing antioxidants such as green tea extract with proteins and polysaccharides, forming a composite matrix to encapsulate the active ingredients through heat denaturation (80-100°C), and then extruding and molding. This technology is aimed at pet food, with an antioxidant addition amount of 0.5-2 wt%, emphasizing storage stability.

[0004] However, while heat denaturation encapsulation can initially prevent oxidation, it is sensitive to high-temperature drying (>130°C), with an activity retention rate of <60%. The lack of a pH response mechanism results in a degradation rate of up to 50% for green tea polyphenols in gastric acid (pH 1-3), and an intestinal absorption rate of <10%. In addition, this method does not optimize ingredient adhesion, making it easy for ingredients to detach from the surface of pet food (adhesion rate <70%), affecting intake consistency and sensory quality (such as bitterness exposure). Processing costs increase by more than 20% due to the addition of extra protein.

[0005] Announcement No. WO2021176445A1 discloses a technology for encapsulating antioxidants (such as polyphenols) using alginate-based microcapsules. The technology involves dispersing the active ingredient in a sodium alginate solution, emulsifying it, and then dripping it into a calcium ion solution to crosslink and form a pH-sensitive shell (alginate content 85wt%). This technology is suitable for general food-grade delivery, and the microcapsule stability is maintained at >90% between pH 3 and 7.

[0006] While this technology achieves pH gradient-responsive release (stable in acidic conditions, swellable in alkaline conditions), its simple single-emulsion structure cannot effectively encapsulate hydrophilic and hydrophobic components (such as curcumin and green tea polyphenols) in separate zones, resulting in a core leakage rate >15%. Furthermore, it lacks an embedding method designed for the porous structure of pet food, leading to uneven adhesion (<80%), and neglects auxiliary solvents such as phospholipids, resulting in limited improvement in bioavailability (<25%). In pet-specific processes, the absence of a freeze-drying step results in 30% oxidative loss during storage, which is detrimental to industrial production.

[0007] In summary, while existing pet antioxidant food technologies have made progress in single-ingredient protection or coating processes, they generally suffer from poor stability, low bioavailability, uneven adhesion, and weak process compatibility. These shortcomings reduce antioxidant efficacy and fail to meet the refined requirements of pet health. Summary of the Invention

[0008] Therefore, the purpose of this invention is to provide a pet antioxidant food with added natural plant active ingredients and its preparation method, which achieves component zone protection, targeted release, uniform embedding and sensory optimization, thereby improving the pet's antioxidant effect and the product's industrial applicability.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A pet food with added natural plant-based active ingredients for antioxidant benefits, comprising:

[0011] Basic pet food pellets;

[0012] Composite microcapsules;

[0013] The composite microcapsule contains an active core and a hydrogel shell that encapsulates the active core. The active core contains a complex formed by curcumin and phospholipids, as well as green tea polyphenols.

[0014] The present invention is further configured such that: the active core has a complex emulsion structure, the structure comprising:

[0015] The internal aqueous phase contains pure water and green tea polyphenols;

[0016] The oil phase, which encapsulates the aqueous phase, contains medium-chain triglycerides and curcumin-phospholipid complexes;

[0017] The mass ratio of curcumin to phospholipids is 1:1 to 1:5; the mass ratio of oil phase to internal aqueous phase is 1:0.5 to 1:2; the content of curcumin in the total weight of the active core is 0.1-5 wt%, and the content of green tea polyphenols in the total weight of the active core is 0.05-3 wt%.

[0018] The present invention is further configured such that: the composite microcapsule is partially embedded in the porous structure of the base particles, and is attached to the surface of the base particles and the inner wall of the pores by means of a layer of chicken fat; the amount of composite microcapsule applied accounts for 0.5-10 wt% of the weight of the base particles.

[0019] The present invention is further configured such that the hydrogel shell remains structurally stable in an environment with a pH value below 4.0, while it swells or disintegrates in an environment with a pH value above 6.0;

[0020] The hydrogel shell comprises alginate formed by ionic crosslinking, and the alginate content in the hydrogel shell is 80-95 wt%.

[0021] A method for preparing an antioxidant pet food, comprising the following steps:

[0022] S1. Preparation of basic pellets: Pet food basic pellets are prepared by mixing, extrusion puffing, drying and cooling processes.

[0023] S2. Prepare microcapsules by forming a complex of curcumin and phospholipids, and then encapsulating the complex and green tea polyphenols together in a hydrogel shell to form composite microcapsules.

[0024] S3. Apply microcapsules: After the base particles have cooled, apply the composite microcapsules prepared in step S2 onto the base particles.

[0025] The present invention is further configured such that step S1, which involves preparing the basic particles, includes:

[0026] S11. Mix pet food ingredients containing at least one protein ingredient and at least one starch ingredient, and extrude and puff them at a temperature of 80-120°C.

[0027] S12. Dry the expanded material at a temperature of 130-150°C for 10-15 minutes;

[0028] S13. Reduce the temperature to 100-120°C and dry for 10-15 minutes, so that the final moisture content is less than 10%;

[0029] S14. Cool the dried material to room temperature.

[0030] The present invention is further configured such that step S3, applying the microcapsules, specifically includes:

[0031] S31. Place the cooled pet food base pellets in a vacuum chamber and evacuate the pressure to below 10 kPa.

[0032] S32. Under pressure below 10 kPa, inject chicken fat at a temperature of 40-60°C into the vacuum chamber and maintain for 2-5 minutes, wherein the amount of chicken fat injected accounts for 5-15 wt% of the weight of the base particles;

[0033] S33. Under the condition of restoring the pressure to 30-50 kPa, spray the composite microcapsule powder prepared in step S2 into the vacuum chamber for 5-15 minutes.

[0034] S34. Stop vacuuming and restore normal pressure.

[0035] The present invention is further configured such that step S2, the process of preparing microcapsules, includes:

[0036] S21. Dissolve green tea polyphenols in pure water to form an internal aqueous phase;

[0037] S22. Curcumin and phospholipids are mixed in a mass ratio of 1:1 to 1:5 to form a "plant-phospholipid complex". The complex is then dissolved in medium-chain triglycerides to form an oil phase (O).

[0038] S23. Disperse the internal aqueous phase (W1) in the oil phase (O) at a mass ratio of 1:0.5 to 1:2, and emulsify at 5000-10000 rpm to form a W1 / O primary emulsion;

[0039] S24. Disperse the W1 / O colostrum in an external aqueous phase (W2) containing 1-5 wt% sodium alginate, and emulsify at 2000-5000 rpm to form a W1 / O / W2 double emulsion;

[0040] S25, gelling the external aqueous phase (W2), which includes:

[0041] S251. Add the double emulsion to a 1-3 wt% calcium chloride solution for cross-linking for 5-15 minutes;

[0042] S252. Transfer the formed microcapsules to a 0.1-0.5 wt% dilute calcium chloride solution and let them mature for 10-20 minutes.

[0043] The present invention is further configured such that, after step S25, the following steps are included:

[0044] S26. Pre-freeze the solidified and washed hydrogel microcapsules at -40°C to -50°C for 4-8 hours;

[0045] S27. Under conditions of vacuum degree below 20 Pa and plate temperature of -10°C to 0°C, perform main drying for 10-20 hours;

[0046] S28. Raise the temperature of the plate to 20°C to 30°C and perform analytical drying for 5-10 hours under a vacuum of less than 10Pa to obtain dried microcapsule powder.

[0047] The present invention is further configured such that: the content of curcumin in the active core is 0.1-5 wt%, and the content of green tea polyphenols in the active core is 0.05-3 wt%;

[0048] In step S3, the amount of composite microcapsules applied accounts for 0.5-10 wt% of the weight of the base particles, and the particle size of the prepared composite microcapsules is 10-500 μm.

[0049] Compared with the shortcomings of the prior art, the beneficial effects of the present invention are as follows:

[0050] This invention constructs a curcumin-phospholipid complex and utilizes W1 / O / W2 dual emulsion technology to encapsulate water-soluble green tea polyphenols and fat-soluble curcumin in a microcapsule. Combined with freeze-drying, this greatly isolates the effects of external environmental factors such as light, oxygen, and humidity on these two unstable active ingredients.

[0051] Utilizing the pH-sensitive properties of the alginate hydrogel shell—stable in acidic environments and swelling and disintegrating in neutral to alkaline environments—this invention enables microcapsules to pass smoothly through a pet's stomach, reaching the intestines before releasing the active core. This targeted release mechanism avoids degradation of the active ingredient by gastric acid, significantly improving its bioavailability and allowing for more effective absorption and antioxidant effects.

[0052] Using a vacuum spraying process, negative pressure is used to "absorb" chicken fat into the pores of the base particles, and then the microcapsule powder is "embedded" into the oily surface and the inner walls of the pores. This method not only achieves an adhesion rate of up to 98%, but also ensures that the microcapsules are evenly distributed, eliminating dust problems and guaranteeing the accuracy of the dosage ingested by pets at each meal. At the same time, the chicken fat also enhances the palatability of the product.

[0053] By utilizing a complex emulsion structure, water-soluble green tea polyphenols are placed in the inner aqueous phase and fat-soluble curcumin complexes are placed in the oil phase. This successfully encapsulates two active ingredients with different solubilities in the same carrier, simplifying the production process and potentially producing a synergistic effect when exerting their efficacy. Attached Figure Description

[0054] Figure 1 This is a process flow diagram of the present invention;

[0055] Figure 2 This is a comparison chart of the adhesion rates of the microcapsules of the present invention;

[0056] Figure 3 This is a comparison chart of the storage stability trends of the active ingredients in this invention;

[0057] Figure 4 This is a comparison chart of the cumulative release of various samples during simulated in vitro digestion in this invention. Detailed Implementation

[0058] Reference Figure 1 The preparation method of the pet antioxidant food of the present invention is described below, with specific steps as follows:

[0059] Example 1:

[0060] The first step is to prepare the basic particles:

[0061] The pet food ingredients are mixed together. The ingredient formula (by weight percentage) is as follows: 30% chicken meal, 15% fish meal, 25% corn, 10% rice, 8% chicken fat, 5% beet pulp, 5% vitamin and mineral premix, 1% yucca extract, and 1% choline chloride. The above ingredients are mixed in a horizontal ribbon mixer for 20 minutes, and then extruded and expanded in a twin-screw extruder at a temperature of 80°C.

[0062] The expanded granular material is fed into a belt dryer and dried at 130°C for 15 minutes.

[0063] Lower the temperature to 100°C and continue drying for 15 minutes to control the moisture content of the final granules to around 8%.

[0064] The dried base particles are cooled to room temperature (approximately 25°C) using an air-cooling system and then set aside.

[0065] The second step is to prepare the composite microcapsules:

[0066] Preparation of the inner aqueous phase (W1): Accurately weigh 1g of green tea polyphenols (purity ≥98%), completely dissolve them in 99g of pure water, stir evenly, and form a homogeneous and transparent inner aqueous phase solution.

[0067] Preparation of the oil phase (O): 5g of curcumin (purity ≥95%) and 5g of phospholipid (soybean phospholipid) were mixed at a mass ratio of 1:1 and stirred in a 40°C water bath for 30 minutes until a homogeneous orange oily liquid of "plant-phospholipid complex" was formed. Subsequently, the complex was completely dissolved in 90g of medium-chain triglycerides (MCT) to form a clear oil phase.

[0068] Preparation of W1 / O primary emulsion: The prepared aqueous phase (W1) was slowly added to the oil phase (O) to achieve a mass ratio of 1:1 between the oil phase and the aqueous phase. Emulsification was performed for 10 minutes at 5000 rpm using a high-speed shear emulsifier to form a stable W1 / O primary emulsion.

[0069] Preparation of W1 / O / W2 double emulsion: Dissolve 3g of sodium alginate in 97g of pure water to form an external aqueous phase (W2) with a mass fraction of 3wt%. Slowly disperse the W1 / O pre-emulsion prepared in the previous step into the external aqueous phase (W2), and emulsify it for 5 minutes at 2000rpm using a high-speed shear emulsifier to form a uniform W1 / O / W2 double emulsion.

[0070] Gelation and Curing: The emulsion was evenly dropped into a 2wt% calcium chloride solution using a nozzle, and an ionic cross-linking reaction was carried out for 5 minutes under gentle stirring. At this time, sodium alginate reacted with calcium ions to form a gel shell.

[0071] The initially formed microcapsules were filtered out and transferred to a 0.2 wt% dilute calcium chloride solution for further aging for 10 minutes to enhance their structural strength and stability.

[0072] Freeze-drying: The matured and washed hydrogel microcapsules were pre-frozen at -40°C for 8 hours. They were then transferred to a freeze dryer and subjected to primary drying at a vacuum of 18 Pa and a plate temperature of -10°C for 20 hours. Finally, the plate temperature was raised to 20°C, and desorption drying was performed at a vacuum of 8 Pa for 10 hours to obtain dried microcapsule powder with an average particle size of approximately 150 μm. Ultimately, curcumin accounted for 2.5 wt% of the total weight of the active core, and green tea polyphenols accounted for 0.5 wt% of the total weight of the active core.

[0073] Third step: Applying microcapsules:

[0074] The equipment used in this step is a vacuum roller sprayer, whose core structure is a rotatable sealed roller (vacuum chamber) connected to a vacuum pump, a liquid nozzle (for spraying chicken fat) and a powder nozzle (for spraying microcapsules).

[0075] Place 100 kg of cooled pet food base pellets in a vacuum drum, seal it, and evacuate it until the pressure is below 8 kPa.

[0076] Under vacuum conditions, 10 kg (10 wt% of the weight of the base granules) of chicken fat at 40°C is sprayed into the drum through a liquid nozzle while the drum rotates at 5 rpm for 5 minutes.

[0077] The vacuum environment removes the air from the pores inside the basic particles. When liquid chicken fat is injected, the pressure difference between the inside and outside drives the chicken fat to quickly penetrate and fill the deep pores, achieving "internal wetting".

[0078] Slowly increase the pressure back to 30 kPa, and evenly spray 5 kg (5 wt% of the weight of the base particles) of composite microcapsule powder into the roller through the powder nozzle. The roller continues to rotate. After this process lasts for 10 minutes, stop the vacuuming and restore normal pressure. Continue to rotate the roller for 2 minutes to make the coating more uniform, and finally obtain the finished pet antioxidant food sample 1.

[0079] After the microcapsule powder is sprayed in, it adheres firmly to the surface of the particles and the inner walls of the pores that have been soaked and covered with chicken fat. The chicken fat then acts as a natural binder, embedding and fixing the microcapsules within the porous structure.

[0080] Specific steps of Example 2: After mixing the same pet food raw materials as in Example 1 evenly, the mixture is extruded and expanded in a twin-screw extruder at a temperature of 120°C; the expanded material is dried at a temperature of 150°C for 10 minutes, and then the temperature is lowered to 120°C for 10 minutes to make the final moisture content less than 10%; the dried material is then cooled to room temperature.

[0081] Preparation of the oil phase (O): Curcumin and phospholipids were mixed at a mass ratio of 1:5 to form a "plant-phospholipid complex". The complex was then dissolved in medium-chain triglycerides to form the oil phase.

[0082] Preparation of W1 / O colostrum: The internal aqueous phase (W1) is dispersed in the oil phase (O) at a mass ratio of 1:2 and emulsified at 10,000 rpm to form W1 / O colostrum.

[0083] Preparation of W1 / O / W2 double emulsion: The W1 / O colostrum was dispersed in an external aqueous phase (W2) containing 5 wt% sodium alginate and emulsified at 5000 rpm to form a W1 / O / W2 double emulsion. The double emulsion was then dropped into a 3 wt% calcium chloride solution for cross-linking for 15 minutes to obtain microcapsules. The formed microcapsules were then transferred to a 0.5 wt% dilute calcium chloride solution and matured for 20 minutes.

[0084] The solidified and washed hydrogel microcapsules were pre-frozen at -50°C for 8 hours; then, they were subjected to primary drying for 20 hours under vacuum conditions below 20 Pa and plate temperature of 0°C; finally, the plate temperature was raised to 30°C and subjected to analytical drying for 10 hours under vacuum conditions below 10 Pa to obtain dried microcapsule powder.

[0085] Place the cooled pet food base pellets in a vacuum chamber and evacuate the chamber to a pressure below 10 kPa. Inject chicken fat at 60°C into the vacuum chamber and maintain the temperature for 5 minutes. The amount of chicken fat injected should be 15 wt% of the weight of the base pellets.

[0086] Under pressure restored to 50 kPa, the prepared composite microcapsule powder was sprayed into the vacuum chamber for 15 minutes, with the amount of composite microcapsules accounting for 10 wt% of the weight of the base particles. The vacuum was then stopped and the pressure was restored to normal. The drum was rotated for another 2 minutes to make the coating more uniform, and finally, the finished pet antioxidant food sample 2 was obtained.

[0087] Example 3, the specific steps are as follows:

[0088] After the same pet food ingredients as in Example 1 are mixed evenly, they are extruded and expanded in a twin-screw extruder at a temperature of 100°C.

[0089] The expanded material was dried at 140°C for 12 minutes.

[0090] Reduce the temperature to 110°C and dry for 12 minutes to reduce the final moisture content to below 10%.

[0091] Cool the dried material to room temperature.

[0092] Preparation of the oil phase (O): Curcumin and phospholipids were mixed at a mass ratio of 1:3 to form a "plant-phospholipid complex". The complex was then dissolved in medium-chain triglycerides to form the oil phase.

[0093] Preparation of W1 / O colostrum: The internal aqueous phase (W1) is dispersed in the oil phase (O) at a mass ratio of 1:1 and emulsified at 7500 rpm to form W1 / O colostrum.

[0094] Preparation of W1 / O / W2 double emulsion: The W1 / O primary emulsion was dispersed in an external aqueous phase (W2) containing 3wt% sodium alginate and emulsified at 3500 rpm to form the W1 / O / W2 double emulsion.

[0095] Add the double emulsion to a 2wt% calcium chloride solution and allow it to crosslink for 10 minutes.

[0096] The formed microcapsules were transferred to a 0.3 wt% dilute calcium chloride solution and aged for 15 minutes.

[0097] The solidified and washed hydrogel microcapsules were pre-frozen at -45°C for 6 hours; then, they were subjected to primary drying for 15 hours under vacuum conditions below 20 Pa and plate temperature of -5°C; finally, the plate temperature was raised to 25°C and subjected to desorption drying for 8 hours under vacuum conditions below 10 Pa to obtain dried microcapsule powder.

[0098] Place the cooled pet food base pellets in a vacuum chamber and evacuate the chamber until the pressure is below 10 kPa.

[0099] Chicken oil at 50°C was sprayed into the vacuum chamber and kept there for 3 minutes. The amount of chicken oil sprayed was 10 wt% of the weight of the base particles.

[0100] Under pressure restored to 40 kPa, the prepared composite microcapsule powder was sprayed into the vacuum chamber for 10 minutes, with the amount of composite microcapsules accounting for 5 wt% of the weight of the base particles. The vacuum was then stopped and the pressure was restored to normal. The drum was rotated for another 2 minutes to make the coating more uniform, and finally, the finished pet antioxidant food sample 3 was obtained.

[0101] Comparative Example 1 was prepared using the same method as in Example 3, but the microencapsulation process of the active ingredient was omitted; instead, it was directly mixed with chicken oil and then sprayed on. The specific steps are as follows:

[0102] Preparation of basic particles: exactly the same as in Example 3.

[0103] Preparation of the active ingredient mixed oil: This step replaces step two in Example 3. Specifically, curcumin and phospholipids are mixed at a mass ratio of 1:3 to form a "plant-phospholipid complex". Then, this complex and green tea polyphenol powder are directly dispersed in an equal amount (10 wt% of the base particle weight) of chicken oil in Example 3, and stirred and mixed evenly at 50°C to form the active ingredient mixed oil to be sprayed. The total amount of active ingredients added is consistent with the amount added by microcapsules in Example 3.

[0104] Apply active ingredient mixture: Place the cooled pet food base pellets in a vacuum chamber and evacuate to a pressure below 10 kPa.

[0105] Under pressure below 10 kPa, the active ingredient mixture prepared in step S2' was sprayed into the vacuum chamber and maintained for 3 minutes. The vacuuming was then stopped and the pressure was restored to normal. The final product obtained was sample 4.

[0106] Comparative Example 2 uses the same preparation method as Example 3, with identical microcapsule preparation procedures, but employs a conventional atmospheric pressure spraying and mixing method when applying the microcapsules. The specific steps are as follows:

[0107] Preparation of basic particles: exactly the same as in Example 3.

[0108] Preparation of composite microcapsules: exactly the same as in Example 3.

[0109] Applying microcapsules at atmospheric pressure: This step replaces step three in Example 3. Specifically, 100 kg of cooled pet food base pellets are placed in an atmospheric pressure drum mixer. While the drum rotates, 10 kg of 50°C chicken fat and 5 kg of the composite microcapsule powder prepared in step S2 are simultaneously or sequentially sprayed onto the surface of the pellets through a nozzle. The mixture is continuously mixed for 15 minutes until the surface coating is uniform. The final product is Sample 5.

[0110] Comparative Example 3: This example uses a simple O / W emulsion method for encapsulation, which is difficult to effectively encapsulate water-soluble green tea polyphenols. The specific steps are as follows:

[0111] Preparation of basic particles: exactly the same as in Example 3.

[0112] Preparation of simplified microcapsules: This step replaces step two in Example 3, specifically as follows:

[0113] Green tea polyphenols are dissolved in pure water to form an aqueous phase.

[0114] Curcumin and phospholipids were mixed at a mass ratio of 1:3 to form a complex, which was then dissolved in medium-chain triglycerides to form an oil phase.

[0115] The aqueous and oil phases were simply mixed, and this mixture was then directly dispersed in an outer aqueous phase (W2) containing 3 wt% sodium alginate, and emulsified at 3500 rpm to form an emulsion. Due to the lack of a stable inner aqueous phase structure, most of the green tea polyphenols rapidly diffused into the outer aqueous phase. The subsequent gelation, ripening, and freeze-drying processes were the same as in Example 3. The application of microcapsules was exactly the same as in Example 3. The final product obtained was Sample 6.

[0116] Based on the samples 1-6 obtained above, we conducted tests as follows:

[0117] Microcapsule adhesion rate test:

[0118] Accurately weigh 100g of finished grain and place it on a vibrating sieve with a 40-mesh screen. Vibrate at a frequency of 300 times / minute for 5 minutes. Collect and weigh the mass (m) of the microcapsule powder that passes through the sieve. The initial mass of added microcapsules is (M). Calculation formula: Adhesion rate (%) = [(M - m) / M] × 100%

[0119] Storage stability test of active ingredients: Each group of samples was placed in a constant temperature and humidity chamber at 37°C and 75% relative humidity for 30 days of accelerated aging test. Samples were taken on day 0 and day 30, and the contents of curcumin and green tea polyphenols in the samples were determined by high performance liquid chromatography (HPLC).

[0120] Calculation formula: Content retention rate (%) = (Content measured on day 30 / Content measured on day 0) × 100%

[0121] In vitro simulated digestion and release test:

[0122] Simulated gastric juice release: Take 10g of sample and add it to 100mL of artificial gastric juice (SGF, pH=2.0, containing pepsin), and shake at 37°C for 2 hours. Measure the content of active ingredients released into the solution.

[0123] Simulated intestinal fluid release: The gastric digestive residue was transferred to 100 mL of simulated intestinal fluid (SIF, pH=6.8, containing trypsin) and shaken at 37°C for 4 hours. The total amount of active ingredients released during the intestinal fluid stage was determined.

[0124] Calculation formula: Release rate (%) = (Amount of active ingredient released in a specific digestive solution / Total amount of active ingredient in the sample) × 100%.

[0125] Based on the above test results, see Table 1 below:

[0126]

[0127] As attached Figure 2-4 illustrate:

[0128] Sample 4 (without microcapsules) vs. Sample 3 (with microcapsules): Sample 4 showed extremely low retention of active ingredients and rapid degradation in simulated gastric juice, demonstrating the irreplaceable key role of microcapsule technology in protecting active ingredients and preventing their degradation during storage and in the gastric environment.

[0129] Sample 5 (atmospheric pressure spraying) vs. Sample 3 (vacuum spraying): The microcapsule adhesion rate of Sample 5 was only 61.7%, far lower than that of Sample 3 (98.5%). This indicates that a large number of microcapsules detach during transportation and handling, resulting in significant loss of active ingredients and uneven dosage. This highlights the significant advantages of vacuum spraying technology in achieving efficient and robust adhesion.

[0130] Sample 6 (simple emulsion) vs. Sample 3 (double emulsion structure): Sample 6 showed significantly poorer protection of green tea polyphenols (retention rate of only 45.8%), and exhibited significant leakage in gastric juice (release rate of 35.4%). This is because simple emulsification cannot form a stable "water-in-oil-in-water" structure to effectively isolate the green tea polyphenols in the aqueous phase. This comparison strongly demonstrates the necessity and advancement of the W1 / O / W2 double emulsion structure for simultaneously and efficiently encapsulating and protecting both water-soluble and lipid-soluble active ingredients.

[0131] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any ordinary changes and substitutions made by those skilled in the art within the scope of the technical solutions of the present invention should be included within the protection scope of the present invention.

Claims

1. A pet antioxidant food with natural plant active ingredients, comprising: a pet food base particle; a composite microcapsule; wherein the composite microcapsule comprises an active core and a hydrogel shell covering the active core, the active core contains a complex of curcumin and phospholipid, and green tea polyphenol.

2. The pet antioxidant food to which natural plant active ingredients are added according to claim 1, characterized by, the active core has a multiple emulsion structure, which includes: an inner aqueous phase containing pure water and green tea polyphenol; an oil phase containing medium-chain triglyceride and curcumin-phospholipid complex covering the inner aqueous phase; wherein the mass ratio of curcumin to phospholipid is 1:1 to 1:5; the mass ratio of oil phase to inner aqueous phase is 1:0.5 to 1:2; the content of curcumin in the total weight of the active core is 0.1-5wt%, and the content of green tea polyphenol in the total weight of the active core is 0.05-3wt%.

3. The pet antioxidant food to which natural plant active ingredients are added according to claim 1, characterized by, The composite microcapsule is partially embedded in the pore structure of the base particle and adheres to the surface and pore wall of the base particle by a layer of chicken oil; the application amount of the composite microcapsule is 0.5-10wt% of the weight of the base particle.

4. The pet antioxidant food with natural plant active ingredients added according to claim 1, characterized in that, The hydrogel shell remains structurally stable in an environment with a pH value below 4.0, and swells or disintegrates in an environment with a pH value above 6.0; The hydrogel shell includes alginate formed by ionic cross-linking, and the content of alginate in the hydrogel shell is 80-95wt%.

5. A preparation method of the pet antioxidant food according to claim 1, comprising the following steps: S1, preparing the base particle, using mixing, extrusion puffing, drying and cooling processes to prepare the pet food base particle; S2, preparing the microcapsule, forming a complex of curcumin and phospholipid, and then embedding the complex and green tea polyphenol in a hydrogel shell to form a composite microcapsule; S3, applying the microcapsule, after cooling the base particle, applying the composite microcapsule prepared in step S2 to the base particle.

6. The method of claim 5, wherein the pet antioxidant chow is prepared by mixing the antioxidant and the pet food together. The process of step S1 for preparing the base particle includes: S11, mixing pet food raw materials containing at least one protein raw material and at least one starchy raw material, and extruding and puffing at a temperature of 80-120°C; S12, drying the puffed material at a temperature of 130-150°C for 10-15 minutes; S13, reducing the temperature to 100-120°C for 10-15 minutes to reduce the final moisture content to less than 10%; S14, cooling the dried material to room temperature.

7. The method for preparing pet antioxidant food according to claim 5, characterized in that, Step S3 of applying the microcapsule specifically includes: S31, placing the cooled pet food base particle in a vacuum chamber and vacuumizing to a pressure below 10kPa; S32, under the condition of a pressure below 10kPa, spraying chicken oil with a temperature of 40-60°C into the vacuum chamber and maintaining for 2-5 minutes, wherein the spraying amount of chicken oil is 5-15wt% of the weight of the base particle; S33, under the condition of restoring the pressure to 30-50kPa, spraying the composite microcapsule powder prepared in step S2 into the vacuum chamber for 5-15 minutes; S34, stopping vacuumizing and restoring normal pressure.

8. The method of claim 5, wherein the pet antioxidant chow is prepared by the steps of: The process of step S2 for preparing the microcapsule includes: ​ S21, dissolving green tea polyphenol in pure water to form an inner aqueous phase; S22, mixing curcumin and phospholipid with mass ratio 1:1 to 1:5 to form "plant-phospholipid complex", then dissolving the complex in medium-chain triglyceride to form oil phase; S23, dispersing inner water phase in oil phase with mass ratio 1:0.5 to 1:2, emulsifying to form W1 / O primary emulsion under 5000-10000 rpm; S24, dispersing W1 / O primary emulsion in outer water phase containing 1-5 wt% sodium alginate, emulsifying to form W1 / O / W2 multiple emulsion under 2000-5000 rpm; S25, gelling outer water phase, which includes: S251, crosslinking multiple emulsion droplets in 1-3 wt% calcium chloride solution for 5-15 minutes; S252, transferring the formed microcapsules to 0.1-0.5 wt% dilute calcium chloride solution for curing for 10-20 minutes.

9. The method of claim 5, wherein the pet antioxidant chow is prepared by mixing the antioxidant and the pet food together. After step S25, the following steps are included: S26, pre-freezing the hardened and washed hydrogel microcapsules at -40°C to -50°C for 4-8 hours; S27, performing main drying under the condition of vacuum degree less than 20 Pa and plate layer temperature -10°C to 0°C for 10-20 hours; S28, increasing plate layer temperature to 20°C to 30°C, performing desorption drying under the condition of vacuum degree less than 10 Pa for 5-10 hours to obtain dried microcapsule powder.

10. The method for preparing pet antioxidant food according to claim 5, characterized in that, The content of curcumin in the active core is 0.1-5 wt%, and the content of green tea polyphenol in the active core is 0.05-3 wt%; The application amount of the complex microcapsule in step S3 accounts for 0.5-10 wt% of the weight of the base particle, and the particle size of the prepared complex microcapsule is 10-500 μm.

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