A method for preparing soft particle starter material based on low-temperature curing and microencapsulation

Abstract

This invention discloses a method for preparing soft-particle starter feed based on low-temperature curing and microencapsulation, belonging to the field of livestock and poultry feed preparation technology. The method includes basic raw material pretreatment, low-temperature curing, mixing and blending, soft-particle molding, drying and cooling, and screening and packaging steps. The core lies in employing a process of "low-temperature curing + double-layer microencapsulation + soft-particle molding," combined with an excipient system composed of modified chitosan, sodium alginate, and attapulgite solution. Low-temperature curing preserves heat-sensitive nutrients and kills harmful microorganisms; double-layer microencapsulation enables targeted release of core functional components, ensuring their activity; soft-particle molding balances palatability and intestinal protection; and the various components of the excipients synergistically improve feed stability, probiotic colonization rate, and digestibility.

Description

Technical Field

[0001] This invention relates to the field of starter culture material technology, specifically to a method for preparing soft particle starter culture material based on low-temperature curing and microencapsulation. Background Technology

[0002] Creep feed is a crucial transitional feed for piglets before and after weaning, and its quality directly affects piglets' appetite, digestive and absorption efficiency, intestinal health, and later growth performance. At the time of weaning, piglets' digestive system is not yet fully developed, and their intestinal mucosa is delicate, requiring extremely high palatability, physical hardness, and stability of nutritional components in the feed.

[0003] Currently, the main types of creep feed for piglets on the market are hard pellets and powders, but both have obvious drawbacks: Hard pellets are formed by high-temperature pressing, resulting in high hardness and poor palatability. Piglets have difficulty chewing them, and this can easily cause physical damage to their delicate intestinal mucosa, leading to intestinal inflammation. At the same time, during the high-temperature pressing process, heat-sensitive nutrients (such as vitamins and active enzymes) in the feed are easily destroyed, reducing the nutritional value of the feed. Although powders are slightly more palatable than hard pellets, they have problems such as high dust content, which can easily cause respiratory irritation in piglets, significant waste during feeding, and easy absorption of moisture and growth of harmful microorganisms, leading to feed spoilage and affecting the safety of piglets' feed intake, which can then cause intestinal diseases such as diarrhea.

[0004] To address the aforementioned issues, existing technologies attempt to optimize creep feed quality by improving molding processes or adding functional ingredients, but these approaches still have shortcomings: some processes only focus on improving feed hardness without addressing the retention of heat-sensitive nutrients; some technologies add palatability enhancers, probiotics, and other functional ingredients without taking effective protective measures, resulting in these functional ingredients being easily inactivated during storage, transportation, and in the acidic environment of piglets' stomachs, thus failing to exert their intended effects. Furthermore, the existing creep feed excipient systems mostly consist of conventional inert ingredients, making it difficult to synergistically improve feed stability, dispersibility, and intestinal protection.

[0005] Therefore, developing a method for preparing soft-particle creep feed that combines good palatability, high nutrient retention, high activity of functional components, and intestinal protection, and solving the technical defects of existing creep feed, has become an urgent technical problem to be solved in the current livestock and poultry feed industry. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the purpose of this invention is to provide a method for preparing soft particle starter material based on low-temperature curing and microencapsulation, so as to solve the problems mentioned in the background art.

[0007] The present invention solves the technical problem by adopting the following technical solution: This invention provides a soft granule starter feed based on low-temperature curing and microencapsulation, which is composed of the following raw materials in parts by weight: 60-80 parts of basic raw materials, 5-10 parts of core functional components, 3-8 parts of excipients, and 10-15 parts of water. The basic raw materials include 30-40 parts corn flour, 15-20 parts soybean meal, 10-15 parts whey powder, 3-5 parts fish meal, 1-2 parts amino acid premix, 0.5-1 part vitamin premix, and 0.5-1 part mineral premix. The core functional ingredients include 2-3 parts of appetite stimulant, 1-2 parts of digestive enzyme, 1-2 parts of probiotics, 0.5-1 part of antioxidant, and 0.5-1 part of antifungal agent; The excipient is prepared by mixing modified chitosan agent, sodium alginate agent and attapulgite liquid in a weight ratio of (5-7):(3-5):2; The water is sterile deionized water, used to regulate feed humidity and facilitate the formation of soft pellets.

[0008] (1) Preparation of modified chitosan agent Add 3-5 parts of silane coupling agent KH560 and 2-4 parts of nanocellulose to 4-7 parts of chitosan solution with a mass fraction of 2-5%. Stir for 30-60 minutes at 25-30℃ and 300-500 r / min. After stirring evenly, add 3-5 parts of montmorillonite and continue stirring for 1-2 hours to ensure thorough mixing. Then filter to remove the filtrate. Place the filter residue in a vacuum drying oven at 60-70℃ and dry until the moisture content is ≤8%. After removal, pulverize to 80-100 mesh to obtain the modified chitosan agent.

[0009] (2) Preparation of sodium alginate A sodium alginate solution with a mass fraction of 2-5% and a sodium silicate solution with a mass fraction of 5% are mixed at a volume ratio of 1:1. The mixture is stirred at 25°C and 200-300 r / min for 20-30 minutes until homogeneous, thus obtaining the sodium alginate agent.

[0010] (3) Preparation of rettolith solution Add attapulgite, silica, and 5% sodium citrate solution in a weight ratio of (2-3):1:(4-6) into a mixer and stir for 15-20 minutes. After mixing evenly, place the mixture in an ultrasonic device with an ultrasonic power of 200-300W and ultrasonically treat for 30 minutes to obtain a uniformly dispersed attapulgite solution.

[0011] (4) Preparation of excipients The modified chitosan agent, sodium alginate agent and tropite liquid prepared above were added into a ball mill at a weight ratio of (5-7):(3-5):2. The ball mill speed was adjusted to 1000-1500 r / min and the milling was carried out for 2 hours. After the ball milling was completed, the filter was filtered to remove excess water. The filter residue was placed in a vacuum drying oven at 60-70℃ and dried until the water content was ≤8%. After being taken out, it was crushed to 80-100 mesh to obtain the excipient.

[0012] (5) Preparation of core functional components encapsulated in double-layer microcapsules The core functional components were encapsulated using a double-layer microencapsulation technology, and the specific steps are as follows: ① Inner coating: Using enteric material (cellulose acetate phthalate) as the coating carrier, the core functional components are mixed with the enteric material at a weight ratio of 1:2-3, an appropriate amount of sterile deionized water is added, and the mixture is stirred to form a paste. The paste is then dried using a spray drying method (inlet air temperature 80-90℃, outlet air temperature 40-50℃, atomization pressure 0.3-0.5MPa) to obtain inner coated particles. ② Outer coating: Using water-soluble material (maltodextrin) as the coating carrier, the inner coating particles are mixed with the water-soluble material at a weight ratio of 1:1-2, and an appropriate amount of sterile deionized water is added. The mixture is stirred to form a paste, and then dried again using a spray drying method (inlet air temperature 70-80℃, outlet air temperature 35-45℃, atomization pressure 0.2-0.4MPa) to obtain the core functional components of the double-layer microcapsule coating, which are then ready for use.

[0013] 3. Preparation method of soft granular starter feed Specifically, the following steps are included: S1. Pretreatment of basic raw materials: Weigh each basic raw material according to the above weight proportions, and clean and remove impurities from the raw materials to remove mud, sand, impurities and lumps; grind corn flour and soybean meal into 80-100 mesh, and mix them evenly with whey powder, fish meal, amino acid premix, vitamin premix and mineral premix to obtain basic mixed raw materials.

[0014] S2. Low-temperature curing treatment: Place the basic mixed raw materials obtained in S1 into a low-temperature curing device, add some sterile deionized water (accounting for 60-70% of the total water volume), adjust the temperature to 70-80℃, stir at 200-300 r / min, and cure for 20-30 min, during which the moisture content of the material is controlled at 15-20%; after curing, cool to 30-40℃ to obtain the low-temperature cured base material.

[0015] S3. Mixing and blending: Add the prepared excipients and core functional components coated with double-layer microcapsules to the cooled low-temperature matured base material in S2, then add the remaining sterile deionized water, stir in a mixer for 20-30 minutes at a stirring speed of 300-400 r / min, mix evenly to obtain a mixture, and control the moisture content of the mixture to be 25-30%.

[0016] S4. Soft Particle Molding: The mixture obtained in S3 is fed into the soft particle molding machine. The equipment parameters are adjusted as follows: die diameter 2-3mm, pressure roller pressure 0.2-0.3MPa, rotation speed 50-80r / min. Smooth surface and loose and porous soft particles are produced. The hardness of the soft particles is controlled at 50-80N (between 100-150N for hard particles and 0-20N for powder).

[0017] S5. Drying and cooling: Place the soft granules formed in S4 into a low-temperature drying device and dry them at 50-60℃ until the moisture content is ≤10% for 30-40 minutes. After drying, allow them to cool naturally to room temperature (25±2℃).

[0018] S6. Screening and Packaging: The cooled soft granules are screened using a 10-20 mesh sieve to remove broken particles and clumps, resulting in qualified soft granule starter feed. The qualified products are sealed in packaging and stored in a cool, dry, and well-ventilated place to prevent moisture absorption and deterioration.

[0019] Furthermore, the weight parts of the basic raw materials are: 35 parts corn flour, 18 parts soybean meal, 12 parts whey powder, 4 parts fish meal, 1.5 parts amino acid premix, 0.8 parts vitamin premix, and 0.7 parts mineral premix.

[0020] Furthermore, the weight proportions of the core functional components are as follows: 2.5 parts palatability enhancer, 1.5 parts digestive enzyme, 1.5 parts probiotic, 0.8 parts antioxidant, and 0.7 parts antifungal agent; wherein the palatability enhancer is prepared by mixing steviol glycosides and maltol in a weight ratio of 2:1, the digestive enzyme is prepared by mixing amylase, protease, and lipase in a weight ratio of 3:2:1, and the probiotic is prepared by mixing Bacillus subtilis and Bacillus licheniformis in a weight ratio of 1:1.

[0021] Furthermore, the weight ratio of the excipients is: 6 parts modified chitosan agent, 4 parts sodium alginate agent, and 2 parts attapulgite solution; in the preparation of the modified chitosan agent, the mass fraction of the chitosan solution is 3%, and the weight parts of each raw material are: 5 parts chitosan solution, 4 parts silane coupling agent KH560, 3 parts nanocellulose, and 4 parts montmorillonite.

[0022] Furthermore, in S2, the low-temperature curing temperature is 75℃, the curing time is 25min, and the material moisture content is controlled at 18%; in S4, the diameter of the soft particle forming die is 2.5mm, the pressure of the roller is 0.25MPa, the rotation speed is 65r / min, and the hardness of the soft particles is controlled at 60-70N; in S5, the drying temperature is 55℃, the drying time is 35min, and the moisture content of the dried soft particles is controlled at 8-10%.

[0023] Furthermore, in the double-layer microcapsule coating, the weight ratio of the core functional component to the enteric material in the inner coating is 1:2.5, and the weight ratio of the inner coating particles to the water-soluble material in the outer coating is 1:1.5. The spray drying parameters are optimized as follows: the inlet air temperature of the inner coating is 85℃, the outlet air temperature is 45℃, and the atomization pressure is 0.4MPa; the inlet air temperature of the outer coating is 75℃, the outlet air temperature is 40℃, and the atomization pressure is 0.3MPa.

[0024] Compared with the prior art, the present invention has the following beneficial effects: This invention significantly improves palatability: by using soft particle molding technology, the prepared creep feed has a hardness between hard particles and powder, with a smooth surface and loose and porous interior, making it easy for piglets to chew and swallow, avoiding physical damage to the piglets' delicate intestines; at the same time, the double-layer microencapsulated palatability enhancer is slowly released in the piglet's intestines, with a long-lasting palatability flavor, effectively improving the piglets' willingness to eat and feed intake.

[0025] High nutrient retention: The 70-80℃ low-temperature cooking technology can effectively kill harmful microorganisms (such as E. coli and Salmonella) in the basic raw materials, ensuring feed safety, and can also retain heat-sensitive nutrients (such as vitamins and active enzymes) in the raw materials to the greatest extent, avoiding nutrient loss caused by high temperature and improving the nutritional value of feed.

[0026] Stable activity of functional ingredients: The core functional ingredients (appetite enhancers, digestive enzymes, probiotics, etc.) adopt double-layer microencapsulation technology. The inner enteric material protects the functional ingredients from being destroyed by the gastric acid environment of piglets. The outer water-soluble material enables the microcapsules to disperse rapidly in the intestines, achieving targeted release of the functional ingredients. At the same time, the modified chitosan, sodium alginate, and tropite liquid in the excipients work synergistically to further protect the probiotics from colonizing the intestines and improve the utilization rate of the functional ingredients.

[0027] High feed safety: The unique formula of the excipients can improve the stability of creep feed and reduce the risk of moisture absorption and spoilage; low-temperature maturation can kill harmful microorganisms, and probiotics can regulate the balance of intestinal flora in piglets, reduce the occurrence of intestinal diseases such as diarrhea in piglets, and ensure the intestinal health of piglets; no harmful additives are added during the preparation process, which meets the safety standards for livestock and poultry feed. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1 A soft granule starter feed based on low-temperature curing and microencapsulation is composed of the following raw materials in parts by weight: 70 parts of basic raw materials, 7.5 parts of core functional components, 5 parts of excipients, and 12.5 parts of sterile deionized water. The basic raw materials include: 35 parts corn flour, 18 parts soybean meal, 12 parts whey powder, 4 parts fish meal, 1.5 parts amino acid premix, 0.8 parts vitamin premix, and 0.7 parts mineral premix. Key functional ingredients: 2.5 parts palatability enhancer (stevioside and maltol mixed in a 2:1 ratio), 1.5 parts digestive enzymes (amylase, protease, and lipase mixed in a 3:2:1 ratio), 1.5 parts probiotics (Bacillus subtilis and Bacillus licheniformis mixed in a 1:1 ratio), 0.8 parts antioxidant, and 0.7 parts antifungal agent; Excipients: 6 parts modified chitosan agent, 4 parts sodium alginate agent, and 2 parts attapulgite solution.

[0030] Its preparation method includes the following steps: (1) Preparation of key raw materials: ① Modified chitosan agent: Add 4 parts of silane coupling agent KH560 and 3 parts of nanocellulose to 5 parts of chitosan solution with a mass fraction of 3%. Stir at 28℃ and 400r / min for 45min. Then add 4 parts of montmorillonite and continue stirring for 1.5h. After filtration, vacuum dry at 65℃ until the moisture content is ≤8%. Crush to 90 mesh and set aside. ② Sodium alginate solution: Mix 3% sodium alginate solution and 5% sodium silicate solution at a volume ratio of 1:1, stir at 25℃ and 250r / min for 25min, and set aside. ③ Apophyllite solution: Mix 2.5 parts of apophyllite, 1 part of silica, and 5 parts of 5% sodium citrate solution, stir for 18 minutes, and sonicate at 300W for 30 minutes. ④ Excipients: Add the above modified chitosan agent, sodium alginate agent, and tropite liquid into a ball mill at a weight ratio of 6:4:2, ball mill at 1200 r / min for 2 h, filter, vacuum dry at 65℃, and pulverize to 90 mesh for later use. ⑤ Double-layer microencapsulation of core functional components: inner layer coating (core functional components and enteric materials are mixed at a ratio of 1:2.5), spray dried (inlet air temperature 85℃, outlet air temperature 45℃, atomization 0.4MPa); outer layer coating (inner layer particles and water-soluble materials are mixed at a ratio of 1:1.5), spray dried (inlet air temperature 75℃, outlet air temperature 40℃, atomization 0.3MPa), ready for use.

[0031] (2) Preparation of soft granular starter feed: S1. Pretreatment of basic raw materials: Weigh each basic raw material, clean and remove impurities, grind corn flour and soybean meal to 90 mesh, mix evenly to obtain basic mixed raw materials; S2. Low-temperature curing: Place the basic mixed raw materials into a low-temperature curing equipment, add 7.5 parts of sterile deionized water, and cure at 75℃ and 250r / min for 25min, controlling the moisture content to 18%, and cool to 35℃ to obtain the low-temperature curing base material; S3. Mixing and blending: Add 5 parts of excipients, 7.5 parts of double-layer microcapsule-coated core functional ingredients, and 5 parts of sterile deionized water. Stir at 350 r / min for 25 min to obtain a mixture (moisture content 28%). S4. Soft granule molding: The soft granule is fed into a soft granule molding machine with a die diameter of 2.5mm, a pressure roller of 0.25MPa, and a rotation speed of 65r / min to produce soft granules (hardness 65N). S5. Drying and cooling: Dry at 55℃ for 35 minutes until the moisture content is 9%, then cool naturally to room temperature. S6. Screening and Packaging: Screened through a 15-mesh sieve, sealed in packaging, and stored in a cool, dry place.

[0032] Example 2 A soft granule starter feed based on low-temperature curing and microencapsulation is composed of the following raw materials in parts by weight: 60 parts of basic raw materials, 5 parts of core functional components, 3 parts of excipients, and 10 parts of sterile deionized water. The basic ingredients are: 30 parts corn flour, 15 parts soybean meal, 10 parts whey powder, 3 parts fish meal, 1 part amino acid premix, 0.5 parts vitamin premix, and 0.5 parts mineral premix. Key functional ingredients: 2 parts palatability enhancer, 1 part digestive enzyme, 1 part probiotic, 0.5 parts antioxidant, 0.5 parts antifungal agent; Excipients: 5 parts modified chitosan agent, 3 parts sodium alginate agent, and 2 parts attapulgite solution.

[0033] Its preparation method includes the following steps: (1) Preparation of key raw materials: ① Modified chitosan agent: Add 3 parts of silane coupling agent KH560 and 2 parts of nanocellulose to 4 parts of chitosan solution with a mass fraction of 2%. Stir at 25℃ and 300r / min for 30min. Then add 3 parts of montmorillonite and continue stirring for 1h. After filtration, vacuum dry at 60℃ and pulverize to 80 mesh for later use. ② Sodium alginate solution: Mix 2% sodium alginate solution and 5% sodium silicate solution at a volume ratio of 1:1, stir at 25℃ and 200r / min for 20min, and set aside. ③ Pitotite solution: Mix 2 parts pitotite, 1 part silica, and 4 parts sodium citrate solution with a mass fraction of 5%, stir for 15 minutes, and sonicate at 200W for 30 minutes. ④ Auxiliary agents: Add them to the ball mill at a weight ratio of 5:3:2, ball mill at 1000 r / min for 2 hours, filter and dry, then pulverize to 80 mesh for later use; ⑤ Double-layer microcapsule coating of core functional components: inner layer coating (1:2), spray drying (inlet air 80℃, outlet air 40℃, atomization 0.3MPa); outer layer coating (1:1), spray drying (inlet air 70℃, outlet air 35℃, atomization 0.2MPa), for later use.

[0034] (2) Preparation of soft granular starter feed: S1. Pretreatment of basic raw materials: Crush corn flour and soybean meal to 80 mesh and mix them evenly; S2. Low-temperature curing: Curing at 70℃ and 200r / min for 20min, with a moisture content of 15%, then cooling to 30℃; S3. Mixing and blending: Add excipients, microencapsulated functional ingredients and remaining water, stir at 300 r / min for 20 min, water content 25%; S4. Soft granule molding: die hole diameter 2mm, pressure roller pressure 0.2MPa, rotation speed 50r / min, hardness 50N; S5. Drying and cooling: Dry at 50℃ for 30 minutes until the moisture content is 8%, then cool to room temperature; S6. Screening and Packaging: Screened through a 10-mesh sieve and sealed for storage.

[0035] Example 3 A soft granule starter feed based on low-temperature curing and microencapsulation is composed of the following raw materials in parts by weight: 80 parts of basic raw materials, 10 parts of core functional components, 8 parts of excipients, and 15 parts of sterile deionized water. The basic ingredients are: 40 parts corn flour, 20 parts soybean meal, 15 parts whey powder, 5 parts fish meal, 2 parts amino acid premix, 1 part vitamin premix, and 1 part mineral premix. Key functional ingredients: 3 parts palatability enhancer, 2 parts digestive enzymes, 2 parts probiotics, 1 part antioxidant, and 1 part antifungal agent; Excipients: 7 parts modified chitosan agent, 5 parts sodium alginate agent, and 2 parts attapulgite solution.

[0036] Its preparation method includes the following steps: (1) Preparation of key raw materials: ① Modified chitosan agent: Add 5 parts of silane coupling agent KH560 and 4 parts of nanocellulose to 7 parts of 5% chitosan solution, stir at 30℃ and 500r / min for 60min, then add 5 parts of montmorillonite, continue stirring for 2h, filter, vacuum dry at 70℃, and pulverize to 100 mesh for later use. ② Sodium alginate solution: Mix 5% sodium alginate solution and 5% sodium silicate solution at a volume ratio of 1:1, stir at 25℃ and 300r / min for 30min, and set aside. ③ Pitotite solution: Mix 3 parts pitotite, 1 part silica, and 6 parts sodium citrate solution with a mass fraction of 5%, stir for 20 minutes, and sonicate at 300W for 30 minutes. ④ Auxiliary agents: Add them to the ball mill at a weight ratio of 7:5:2, ball mill at 1500 r / min for 2 hours, filter and dry, then pulverize to 100 mesh and set aside. ⑤ Double-layer microcapsule coating of core functional components: inner layer coating (1:3), spray drying (inlet air 90℃, outlet air 50℃, atomization 0.5MPa); outer layer coating (1:2), spray drying (inlet air 80℃, outlet air 45℃, atomization 0.4MPa), for later use.

[0037] (2) Preparation of soft granular starter feed: S1. Pretreatment of basic raw materials: Crush corn flour and soybean meal to 100 mesh and mix evenly; S2. Low-temperature curing: Curing at 80℃ and 300r / min for 30min, with a moisture content of 20%, then cooling to 40℃; S3. Mixing and blending: Add excipients, microencapsulated functional ingredients and remaining water, stir at 400 r / min for 30 min, water content 30%; S4. Soft granule molding: die hole diameter 3mm, pressure roller pressure 0.3MPa, rotation speed 80r / min, hardness 80N; S5. Drying and cooling: Dry at 60℃ for 40 minutes until the moisture content is 10%, then cool to room temperature; S6. Screening and Packaging: Screened through a 20-mesh sieve and stored in a sealed container.

[0038] 1. Hardness testing standards for soft particles The hardness test was performed using a pellet hardness tester, following the procedure outlined in "Method for Determination of Feed Pellets" (GB / T 18823-2018). The specific steps are as follows: (1) Sampling: Randomly select 30 whole soft particles from the starter material to be tested, and remove broken particles and clumps; (2) Testing: Place the soft particles one by one on the testing platform of the particle hardness tester, adjust the testing speed to 5 mm / min, apply pressure until the particles are broken, and record the breaking pressure of each particle (unit: N). (3) Calculation: Take the average crushing pressure of 30 particles as the hardness value of soft particles, and keep the result as an integer.

[0039] 2. Standards for testing the retention rate of heat-sensitive nutrients Taking vitamin C (VC) and amylase as examples, the procedures are as follows: Refer to the "National Standard of the People's Republic of China - Determination of Vitamin C in Feed" (GB / T 14701-2002) and "Determination of Amylase Activity in Feed - Spectrophotometric Method" (GB / T 18634-2009). (1) Sample preparation: Take 10g of the starter culture material to be tested, crush it and put it into a 50mL centrifuge tube, add 30mL of sterile deionized water, extract it by sonication for 20min (power 300W, temperature 25℃), centrifuge for 10min (speed 5000r / min), take the supernatant, filter it through a 0.45μm filter membrane to obtain the test solution; (2) Preparation of reference solution: Accurately weigh appropriate amounts of VC reference standard and amylase reference standard, dissolve and dilute with sterile deionized water to prepare reference solution of corresponding concentration; (3) Detection: The absorbance of the test solution and the reference solution was determined by spectrophotometry, and the VC content and amylase activity in the test solution were calculated according to the standard curve; (4) Calculation: Retention rate of heat-sensitive nutrients = (content of ingredients after cooking / activity ÷ content of ingredients in raw materials / activity) × 100%, and the test results are kept to one decimal place.

[0040] 3. Palatability testing standards The piglet feed intake test method was used, selecting healthy weaned piglets (weighing 7-8 kg), with 10 piglets per group. The specific steps are as follows: (1) Experimental grouping: Piglets were randomly divided into an experimental group (fed the soft pellet creep feed of the present invention) and a control group (fed conventional hard pellet creep feed or powder feed), with 3 replicates in each group and 10 piglets in each replicate; (2) Feeding management: During the 7-day trial period, the piglets were fed regularly and in fixed quantities every day to ensure sufficient feed. The daily feed intake of each group of piglets was recorded. (3) Palatability evaluation: The daily feed intake, feeding speed (feeding time / feed intake) and feeding preference (two feeds are provided at the same time, and the proportion of piglets eating the creep feed of this invention is recorded) are used as evaluation indicators; Palatability scoring standard: 1-3 points (poor), 4-6 points (medium), 7-10 points (excellent), scored by 3 professionals and the average value is taken.

[0041] 4. Standards for testing digestibility and absorption rate Using the digestibility and absorption rates of crude protein and starch as test indicators, the total manure collection method was adopted, and the specific steps are as follows: (1) Experimental grouping: Same as palatability test grouping, experimental period of 7 days, the first 3 days are the adaptation period, and the last 4 days are the formal manure collection period; (2) Sample collection: Accurately record the daily feed intake of piglets, collect all feces of each group of piglets, remove impurities, dry at low temperature to constant weight, crush and set aside; (3) Testing: The crude protein and starch contents in starter feed and feces were determined according to GB / T 6432-2018 and GB / T 5009.9-2016, respectively. (4) Calculation: Digestion and absorption rate = (content of ingredients in feed - content of ingredients in feces) ÷ content of ingredients in feed × 100%, and the test results are kept to one decimal place.

[0042] 5. Standards for testing probiotic activity and intestinal colonization rate (1) Probiotic activity test: The plate count method was used. 1g of the starter culture to be tested was taken, serially diluted, and inoculated on the probiotic selective medium. The culture was carried out at 37℃ for 24-48h, the number of colonies was counted, and the number of viable probiotics per gram of starter culture was calculated (unit: CFU / g). (2) Intestinal colonization rate detection: After the experiment, three piglets were randomly selected from each group. After slaughter, the intestinal contents were taken and the number of live probiotics in the intestinal contents was determined by plate counting method. The intestinal colonization rate was calculated as (number of live probiotics in intestinal contents ÷ number of live probiotics in creep feed) × 100%. The test results were retained to one decimal place.

[0043] 6. Diarrhea Rate Detection Standards Based on the above piglet feeding experiment, the diarrhea of ​​piglets was observed and recorded daily. The criteria for diarrhea were: piglets excreting loose or soft stools, unformed feces, and having diarrhea ≥ 2 times per day. Calculation: Diarrhea rate = (Number of piglets with diarrhea × Number of days with diarrhea) ÷ (Total number of piglets × Number of days of the experiment) × 100%, and the test result is rounded to one decimal place.

[0044] 7. Feed stability testing standards (1) Moisture absorption rate test: Take 10g of the starter material to be tested, place it in an environment with a relative humidity of 80±5% and a temperature of 25℃, and leave it for 72h. Record the weight before and after the placement, and calculate the moisture absorption rate = (weight after placement - weight before placement) ÷ weight before placement × 100%; (2) Corruption rate test: Take 20g of starter feed to be tested, place it in a sealed container, and place it in an environment with a temperature of 30℃ and a relative humidity of 70±5% for 15 days. Observe whether the feed has mold, odor, clumping and other corruption phenomena. Calculate the corruption rate = (weight of corrupted feed ÷ weight of total feed) × 100%. The test result is retained to one decimal place.

[0045] Performance summary of Examples 1-3 To clarify the comprehensive performance of the soft granular starter material of the present invention, the products prepared in Examples 1-3 were comprehensively tested, and the specific data are shown in the table below: The products in Examples 1-3 underwent performance testing, and the test results are as follows:

[0046] To verify the importance of each component in the excipient (modified chitosan agent, sodium alginate agent, and attapulgite solution), three comparative examples were set up to compare with Example 1 (complete excipient system). The specific setup is as follows: Comparative Example 1: The formulation and preparation process are completely consistent with Example 1, except that the modified chitosan agent was not added to the excipients (the excipients are made by mixing 4 parts sodium alginate and 2 parts attapulgite solution, and the preparation process remains unchanged). Comparative Example 2: The formulation and preparation process are completely consistent with Example 1, except that sodium alginate was not added to the excipients (the excipients are made by mixing 6 parts of modified chitosan and 2 parts of attapulgite solution, and the preparation process remains unchanged). Comparative Example 3: The formulation and preparation process were completely consistent with Example 1, except that attapulgite solution was not added to the excipients (the excipients were made by mixing 6 parts of modified chitosan agent and 4 parts of sodium alginate agent, and the preparation process remained unchanged). Comparative Example 4: The formulation and preparation process were completely consistent with Example 1, without the addition of any excipients.

[0047] Performance tests were conducted on the above four comparative examples and Example 1. The test items were the same as those in Examples 1-3. The specific performance data are shown in the table below:

[0048] 1. Probiotic Intestinal Colonization Rate Analysis: The probiotic intestinal colonization rate of Example 1 (complete excipient system) reached 78.5%, significantly higher than that of the comparative examples. Among them, Comparative Example 4 (without any excipients) had the lowest colonization rate (49.2%), and Comparative Example 1 (without modified chitosan) had a colonization rate of only 56.8%, indicating that modified chitosan can significantly enhance the intestinal adhesion ability of probiotics, helping them resist the adverse effects of the intestinal environment and promoting their colonization. The colonization rates of Comparative Example 2 (without sodium alginate) and Comparative Example 3 (without tropite solution) were 62.3% and 68.9%, respectively, indicating that sodium alginate can enhance the stability of probiotics, and tropite solution can optimize the intestinal microenvironment. The synergistic effect of the three can maximize the activity and colonization effect of probiotics.

[0049] 2. Diarrhea Rate Analysis: The diarrhea rate of piglets in Example 1 was only 1.2%, far lower than that of the comparative examples. Comparative Example 4 had the highest diarrhea rate (6.5%), while Comparative Example 1 had a diarrhea rate of 4.7%, indicating that the modified chitosan agent has a good protective effect on the intestinal mucosa and can reduce the occurrence of intestinal inflammation. The diarrhea rates of Comparative Examples 2 and 3 were 3.8% and 2.9%, respectively, indicating that sodium alginate and attapulgite solution can synergistically regulate the balance of intestinal flora in piglets, inhibit the proliferation of harmful bacteria, and thus reduce the incidence of diarrhea. The combination of the three can effectively protect the intestinal health of piglets.

[0050] 3. Analysis of Moisture Absorption and Spoilage Rate: The moisture absorption rate (3.5%) and spoilage rate (0%) of Example 1 were significantly better than those of the comparative examples. Comparative Example 4 had a moisture absorption rate of 7.8% and a spoilage rate of 5.2%, indicating that the additives can significantly improve the stability of starter feed. Among them, the modified chitosan agent has good moisture-proof and antibacterial effects, the sodium alginate agent can enhance the dispersibility and stability of the feed, and the tropite solution can absorb moisture and inhibit the growth of microorganisms. The synergistic effect of the three can effectively reduce the moisture absorption and spoilage of the feed, and extend the shelf life of the feed.

[0051] 4. Crude protein digestibility analysis: The crude protein digestibility of Example 1 was 82.3%. Among the comparative examples, Comparative Example 4 had the lowest rate (72.5%), while Comparative Examples 1, 2, and 3 had rates of 75.2%, 77.6%, and 79.8%, respectively. This indicates that the components of the excipients can synergistically improve the digestibility and absorption of the feed. Modified chitosan can promote intestinal peristalsis, sodium alginate can improve feed dispersibility, and tropite solution can regulate intestinal pH and help digestive enzymes function, thereby improving the digestibility and absorption of nutrients.

[0052] In summary, the modified chitosan agent, sodium alginate agent, and tropite solution are all indispensable excipients in the feed additives. Their synergistic effect can significantly improve the probiotic colonization rate and digestibility of soft granular starter feed, while reducing the diarrhea rate, moisture absorption rate, and spoilage rate. They are the key auxiliary system for achieving the technical effects of this invention. The absence of any one component will significantly reduce the overall performance of the starter feed, further demonstrating the rationality and innovation of the excipient formulation of this invention.

[0053] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0054] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing soft particle starter material based on low-temperature curing and microencapsulation, characterized in that, Includes the following steps: S1. Basic raw material pretreatment: Weigh the basic raw materials according to the weight parts, clean and remove impurities, crush the corn flour and soybean meal to 80-100 mesh, and mix them evenly with whey powder, fish meal, amino acid premix, vitamin premix and mineral premix to obtain basic mixed raw materials. S2. Low-temperature curing treatment: Place the basic mixed raw materials into a low-temperature curing equipment, add sterile deionized water, accounting for 60-70% of the total water volume, adjust the temperature to 70-80℃, stir at 200-300r / min, curing time for 20-30min, control the material moisture content to 15-20%, and cool to 30-40℃ to obtain the low-temperature curing base material. S3. Mixing and blending: Add the excipients and the core functional components with double-layer microcapsule coating to the low-temperature matured base material, then add the remaining sterile deionized water, stir for 20-30 minutes at a stirring speed of 300-400 r / min, and obtain a mixture with a water content of 25-30%. S4. Soft Particle Molding: Feed the mixture into the soft particle molding machine, adjust the die diameter to 2-3mm, the pressure of the pressure roller to 0.2-0.3MPa, and the rotation speed to 50-80r / min to produce soft particles with a hardness of 50-80N, a smooth surface, and a loose and porous interior. S5. Drying and cooling: Dry the soft granules at 50-60℃ until the moisture content is ≤10% for 30-40 minutes, and then let them cool naturally to room temperature. S6. Screening and Packaging: Use a 10-20 mesh sieve for screening, seal the package and store in a cool, dry place.

2. The preparation method according to claim 1, characterized in that, The basic raw materials include 30-40 parts corn flour, 15-20 parts soybean meal, 10-15 parts whey powder, 3-5 parts fish meal, 1-2 parts amino acid premix, 0.5-1 part vitamin premix, and 0.5-1 part mineral premix.

3. The preparation method according to claim 2, characterized in that, The excipients are made by mixing modified chitosan, sodium alginate and tropite solution in a weight ratio of (5-7):(3-5):

2. The core functional components include 2-3 parts of palatability enhancer, 1-2 parts of digestive enzyme, 1-2 parts of probiotics, 0.5-1 parts of antioxidant, and 0.5-1 parts of antifungal agent.

4. The preparation method according to claim 3, characterized in that, The preparation method of excipients includes the following steps: (1) Preparation of modified chitosan agent: Add 3-5 parts of silane coupling agent KH560 and 2-4 parts of nanocellulose to 4-7 parts of chitosan solution with a mass fraction of 2-5%, stir at 25-30℃ and 300-500r / min for 30-60min, then add 3-5 parts of montmorillonite, continue stirring for 1-2h, filter, vacuum dry at 60-70℃ until the water content is ≤8%, and pulverize to 80-100 mesh to obtain modified chitosan agent; (2) Preparation of sodium alginate agent: Mix sodium alginate solution with mass fraction of 2-5% and sodium silicate solution with mass fraction of 5% at a volume ratio of 1:1, stir at 25℃ and 200-300r / min for 20-30min to obtain sodium alginate agent; (3) Preparation of attapulgite solution: attapulgite, silica and 5% sodium citrate solution are mixed and stirred in a weight ratio of (2-3):1:(4-6) for 15-20 min, and ultrasonically treated at 200-300W for 30 min to obtain attapulgite solution; (4) Preparation of excipients: Add modified chitosan agent, sodium alginate agent and tropite liquid into a ball mill at a weight ratio of (5-7): (3-5): 2, ball mill at 1000-1500 r / min for 2 h, filter, vacuum dry at 60-70℃ until the water content is ≤8%, and pulverize to 80-100 mesh to obtain excipients.

5. The preparation method according to claim 4, characterized in that, The method for preparing the core functional component encapsulated in the double-layer microcapsule is as follows: ① Inner coating: Using cellulose acetate phthalate as a carrier, the core functional components are mixed with the carrier at a weight ratio of 1:2-3, sterile deionized water is added to form a paste, spray dried, with inlet air temperature of 80-90℃, outlet air temperature of 40-50℃, and atomization pressure of 0.3-0.5MPa to obtain inner coated particles. ② Outer coating: Using maltodextrin as a carrier, the inner coating particles are mixed with the carrier at a weight ratio of 1:1-2, and sterile deionized water is added to form a paste. The paste is then spray-dried at an inlet temperature of 70-80℃ and an outlet temperature of 35-45℃, with an atomization pressure of 0.2-0.4MPa, to obtain the core functional components coated with double-layer microcapsules.

6. The preparation method according to claim 5, characterized in that, The basic raw materials are in the following weight proportions: 35 parts corn flour, 18 parts soybean meal, 12 parts whey powder, 4 parts fish meal, 1.5 parts amino acid premix, 0.8 parts vitamin premix, and 0.7 parts mineral premix.

7. The preparation method according to claim 6, characterized in that, Among the core functional components, the palatability enhancer is a mixture of steviol glycosides and maltol in a weight ratio of 2:1; the digestive enzyme is a mixture of amylase, protease, and lipase in a weight ratio of 3:2:1; and the probiotic is a mixture of Bacillus subtilis and Bacillus licheniformis in a weight ratio of 1:

1.

8. The preparation method according to claim 7, characterized in that, The weight ratio of the excipients is as follows: 6 parts modified chitosan agent, 4 parts sodium alginate agent, and 2 parts attapulgite solution; in the preparation of the modified chitosan agent, the mass fraction of the chitosan solution is 3%, and the weight parts of each raw material are as follows: 5 parts chitosan solution, 4 parts silane coupling agent KH560, 3 parts nanocellulose, and 4 parts montmorillonite.

9. The preparation method according to claim 8, characterized in that, In S2, the low-temperature curing temperature is 75℃, the curing time is 25min, and the material moisture content is 18%; in S4, the diameter of the die hole for forming soft particles is 2.5mm, the pressure of the roller is 0.25MPa, the rotation speed is 65r / min, and the hardness of the soft particles is 60-70N; in S5, the drying temperature is 55℃, the drying time is 35min, and the moisture content after drying is 8-10%.

10. The preparation method according to claim 9, characterized in that, In the double-layer microcapsule coating, the weight ratio of the core functional component in the inner coating to the carrier is 1: 2.5, the weight ratio of inner layer particles to carrier in the outer coating is 1:1.5; the inner layer spray drying has an inlet air temperature of 85℃, an outlet air temperature of 45℃, and an atomization pressure of 0.4MPa, while the outer layer spray drying has an inlet air temperature of 75℃, an outlet air temperature of 40℃, and an atomization pressure of 0.3MPa.

Images