Microcapsule feed for aquatic animals and preparation method thereof
By preparing an interpenetrating network shell microcapsule structure formed by modified starch, carrageenan, and gelatin, the problem of easy disintegration of aquatic animal feed in water was solved, achieving high water resistance and low leakage, thus improving feed utilization and water quality protection.
Patent Information
- Application Number
- CN202512041854.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-02-27
AI Technical Summary
The single-cell protein particles in existing aquatic animal feeds are prone to water absorption and disintegration in water, resulting in low utilization and affecting water quality. In particular, they have poor stability in seawater and cannot meet the requirements of suspended small particles, low water phase permeability and high water resistance stability.
By employing a microcapsule structure with an interpenetrating network shell formed by modified starch, carrageenan, and gelatin, and by controlling the temperature of the salt solution and the gelation process of the gelatin, microcapsule feed with low aqueous phase permeability and high water resistance and stability was prepared, preventing the feed from prematurely absorbing water and disintegrating in water.
This achieves good suspension stability of microencapsulated feed in water, avoiding nutrient leakage and water pollution, and improving feed utilization and feeding efficiency.
Smart Images
Figure CN121569897A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of aquatic animal feed technology, and particularly relates to a microcapsule feed for aquatic animals and its preparation method. Background Technology
[0002] Single-cell protein is a high-protein biomass produced by the proliferation and accumulation of microorganisms during fermentation, and it has been used as a protein alternative in animal feed. Currently, aquatic animal feeds using single-cell protein as a raw material are mostly pelleted feeds for fish. These pellets are often extruded or compressed, making them prone to water absorption and disintegration in water. This results in low utilization rates and negatively impacts water quality, especially in seawater where their stability is even worse.
[0003] For aquatic animal fry that primarily feed on suspended particles in the water, such as crustaceans like shrimp and tiger prawns in their later larval to postlarval stages (mainly the postlarvae stage, extending to the late mysis stage), and some fish larvae during the transition / acclimation to microparticle-based formulated feeds, their feeding process mainly involves actively preying on suspended particles in the water using their mouthparts. Therefore, the feed must have good stability in the water phase. Existing single-cell protein feeds cannot simultaneously meet the requirements of aquatic animals for small suspended particles, low water phase permeability, and high water stability, especially saltwater stability. Summary of the Invention
[0004] The purpose of this invention is to provide a feed for aquatic animals that has low water phase leakage and high salt water resistance.
[0005] The technical solution of this invention is as follows: A method for preparing microencapsulated feed for aquatic animals includes the following steps: Step 1, Ingredients Preparation of core material slurry: Mix modified starch and nutrient powder with water to make the mixture contain 18-24 wt% water; shear and knead to form a 25 The apparent viscosity is 1000-6000 mPa·s / 25 A uniform core material slurry. The modified starch used can be pregelatinized starch, acetylated starch, hydroxypropylated starch, cross-linked starch, etc., and the type of starch can be corn starch, tapioca starch, potato starch, wheat starch, etc.
[0006] Prepare wall material solution: Prepare 55-80g of carrageenan using type κ or type ι carrageenan. 1.0-3.0 wt% carrageenan aqueous solution; preparation temperature 50-65°C An aqueous solution of gelatin with a mass fraction of 0.5-2.5 wt%. Fish gelatin, porcine gelatin, gelatin peptides, etc., can be used.
[0007] Mix the above carrageenan aqueous solution and gelatin aqueous solution at a mass ratio of gelatin:carrageenan = 0.3-1.5:1 to prepare a wall material solution. Control the temperature of the wall material solution at 55-65°C. ; Step 2, droplet preparation Mix the core material slurry and wall material solution at a dry basis solids mass ratio of 92-99:1-8, and maintain the temperature at 50-60°C. The solution is prepared by dispersing droplets into a salt solution, which is a KCl solution or a mixture of KCl and NaCl; the solute concentration in the salt solution is 0.2-0.8 wt%, and the mass ratio of NaCl to KCl is 0-1:1; the temperature of the salt solution is 35-45°C. ; Step 3: Cooling and drying Cool the above salt solution to 10–20 °C. Add to the salt solution Concentrated solution, The mass concentration is adjusted to 0.05-0.20 wt%, and maintained at 10-20%. Stir gently for 5-15 minutes to maintain uniform suspension of droplets; filter and dry to obtain microcapsule feed for aquatic animals.
[0008] In the above-described method of the present invention, step two involves mixing a core material slurry made from nutrient powder with a wall material solution, and then dripping the mixture into a salt solution for a gelation bath. During the drip feeding process, the mixture of the core material slurry and the wall material solution is maintained at 50-60°C. This prevents premature gelation that could lead to poor droplet formation or tubing blockage. After the droplet enters the salt solution, Diffusion towards the droplet interface occurs because the KCl solution at 35-45 °C places carrageenan in a rapidly gelling, activated state within a specific temperature window. Consequently, carrageenan quickly gels on the droplet surface, forming... - Carrageenan outer shell. Step two, drop preparation, can be done using conventional equipment such as vibrating nozzles, dual-fluid nozzles, or electrostatic assisted drop preparation. The key is to control the temperature to maintain 50-60°C during drop preparation to form the mixture of core and wall materials. This prevents problems such as needle blockage and other pipeline clogging, and also avoids quality issues such as long particle tails and widened size distribution.
[0009] In step three, the salt solution is cooled to 10-20°C, reaching the gelatin's condensation point. In its presence, the gelatin solidifies and interacts with the contents of the outer casing. Crosslinking formation and - Carrageenan-gelatin interpenetrates, thereby forming an interpenetrating network structure within the shell, and during network shaping... - The interpenetrating colloidal network shell is fully shaped after being kept at 10-20°C for 5-15 minutes. The preferred temperature of the salt solution is 12-16°C.
[0010] In step two, if the temperature of the salt solution is too high, for example above 48°C, then - Carrageenan shells may fail to solidify or form slowly, resulting in issues such as droplet formation, stringing, and out-of-roundness. This also leads to poor water resistance and leakage resistance in the shell. Conversely, if the salt solution temperature is too low, such as 30°C... The droplet will instantly form a dense, hard shell on the surface after it is injected, but the interior of the droplet is still relatively high, causing the shell to crack or shrink; and this will cause the dense shell in step three to... It is difficult to penetrate evenly into the shell and form an interpenetrating colloidal outer shell, resulting in brittle particles and increased pulverization rate.
[0011] In step three, if the salt solution temperature is too high and has not dropped to 20°C, the gelatin will remain in a molten state and will not be able to form an interpenetrating hard shell in time; furthermore, due to the high temperature, Excessive cross-linking with gelatin in the local shell causes uneven structure in the shell, resulting in weak salt water shear resistance; its stability in salt water is significantly reduced, and the leakage of protein and amino nitrogen in seawater is significantly increased. In addition, it is prone to cracking in water.
[0012] In step three, if the salt solution temperature is too low and the temperature drops too quickly, reaching 10... The following conditions can easily lead to shrinkage and water separation of the outer shell, resulting in abnormal porosity of the outer shell and cracking after being submerged in water.
[0013] The preparation method of the present invention, through Inducing carrageenan to form a primary shell, followed by cooling to gelatinize; then... The presence of this substance promotes further ionic cross-linking of carrageenan, densifying the shell and thus forming an interpenetrating network (IPN) shell between the carrageenan and gelatin networks, encapsulating the nutrient powder within. - Carrageenan and - The interior of the gelatin interpenetrating colloidal network shell has low aqueous phase leakage and high water resistance stability, thus preventing the microcapsule feed from absorbing water and disintegrating or nutrient leakage prematurely before consumption, improving feed utilization and helping to maintain water quality.
[0014] Preferably, the method for preparing the microencapsulated feed for aquatic animals further includes the following steps: Step 4, oiling: The surface of the microcapsules is coated with oil under vacuum, with the amount of oil being 0-4 wt% of the microcapsules, wherein the oil used is feed oil or edible oil.
[0015] Microcapsules can be placed in a vacuum mixing device, a vacuum is created, and atomized oil is added while mixing. The pressure is then restored to normal, and the mixture is stirred until homogeneous. The vacuum mixing device is preferably a vacuum drum-type oiling device or a vacuum mixing tank with an atomizing oil spray assembly. The vacuum conditions are as follows: MPa, preferably MPa.
[0016] In the above process, vacuuming removes air from the pores inside the particles, opening up the micropores and capillaries on the particle surface. When the particles come into contact with oil under stirring, and then return to normal pressure, the oil penetrates the particles, forming a thin oil film on the microcapsule surface. Stirring at normal pressure makes the oil film more uniform, preventing surface oil spots or localized oil deficiency. Suitable oils include fish oil, krill oil, algae oil, soybean oil, and rapeseed oil. The formation of an oil film on the microcapsule surface and the penetration of oil into the particle's pores, partially replacing air with oil, gradually increases the apparent density from a relatively light position. By adjusting the amount of oil applied, the density can be controlled between 0.98 and 1.05 g / cm³, allowing the microcapsules to maintain different states in water, such as slow sinking or near-neutral suspension, to adapt to the different feeding habits of various aquatic animals. It also provides essential fatty acids and fat-soluble nutrients. Furthermore, an oil application rate of 0–4 wt% only forms a thin, tightly adhered oil film on the microcapsule surface, without affecting water quality.
[0017] Preferably, the temperature of the salt solution added in step two is 38-42°C. Control the temperature between 38-42 degrees Celsius. Within this range, it can effectively prevent the local temperature of the droplet from exceeding 35-45 degrees Celsius during the droplet-making process due to unexpected large temperature fluctuations. The range.
[0018] Preferably, when preparing the wall material solution, a carrageenan aqueous solution and a gelatin aqueous solution are mixed in a mass ratio of gelatin:carrageenan = 0.8-1.2:1.
[0019] Preferably, the nutrient powder is single-cell protein powder or a mixture of single-cell protein powder with at least one of black soldier fly powder, kelp powder, enzymatically hydrolyzed soybean meal powder, algae powder and yeast autolysate powder.
[0020] Single-cell protein is a methyl-trophic microbial biomass cultured on substrates such as methanol, methane, and CO2, and is used as a feed protein source. Using the method of this invention, single-cell protein powder is used as a nutrient powder to produce microencapsulated feed, broadening the protein sources in aquatic animal feed. Single-cell protein powder can also be mixed with any one of black soldier fly powder, kelp powder, enzymatically hydrolyzed soybean meal powder, algae powder, and yeast autolysate powder to produce nutrient powder for microencapsulated feed, thereby improving the nutritional completeness of the feed. For example, the following proportions can be mixed: 8-18 wt% modified starch (preferably 10-15 wt%), 8-20 wt% single-cell protein powder (preferably 10-16 wt%), 4-10 wt% black soldier fly powder (preferably 5-8 wt%), 5-12 wt% enzymatically hydrolyzed soybean meal (preferably 6-10 wt%), 10-30 wt% kelp powder (preferably 15-25 wt%), 8-20 wt% chlorella powder (preferably 10-15 wt%), 2-6 wt% autolysate yeast powder (preferably 3-5 wt%), and 2-6 wt% spirulina powder (preferably 3-5 wt%). Additionally, 0.5-2 wt% mineral premix powder, inulin, and 0.5-3 wt% resistant dextrin can also be added.
[0021] Preferably, the drying in step three is hot air drying at 55-65℃ or fluidized bed drying, and the moisture content after drying is ≤10wt%. Hot air drying or fluidized bed drying helps the microcapsule feed maintain its structural integrity.
[0022] The present invention also provides a microcapsule feed for aquatic animals, which is prepared by the above method.
[0023] Preferably, the density of the microencapsulated feed is 0.98-1.05 g / cm³, which is more conducive to its suspension in water. Good suspension stability in the aqueous phase can prevent rapid sedimentation or aggregation of particles, which would affect feeding efficiency.
[0024] Preferably, the particle size of the microencapsulated feed is D. 50 The particle size is 160-220 μm. Microencapsulated feeds in this particle size range can be used or are preferred for the early larval stages of crustaceans, such as shrimp and tiger prawns during the mysis stage and the transitional stages before and after.
[0025] Preferably, the particle size distribution of the microencapsulated feed satisfies a particle size distribution width (Span) ≤ 0.8. Microencapsulated feed within this particle size range can be used or is preferably used for the later larval or postlarval stages of crustaceans, especially the early postlarvae stage and its transitional phases, as well as for the rearing of some aquatic animals at the seedling stage.
[0026] The beneficial effects of this invention are as follows: The method for preparing microencapsulated feed for aquatic animals according to the present invention involves forming... - Carrageenan and - A gelatin interpenetrating colloidal network shell encapsulates nutrient powders such as single-cell protein powder into microcapsule feed. Due to the low water phase permeability and high water resistance of this interpenetrating colloidal network shell, the microcapsule feed is prevented from absorbing water and disintegrating prematurely before consumption, and nutrients are prevented from leaking out. This makes it easier to use small granular nutrients such as single-cell protein powder in the feeding of aquatic animals without polluting the water. Detailed Implementation
[0027] The present invention will now be described in detail with reference to the embodiments. Example 1
[0028] The method for preparing a microencapsulated feed for aquatic animals is as follows: Step 1, Ingredients Preparation of core material slurry: Mix 8 parts by weight of α-starch and 92 parts by weight of single-cell protein powder with water, adjust the amount of water added to make the mixture contain 21 wt% water; shear and knead to form a uniform core material slurry with an apparent viscosity of 3000 mPa·s / 25°C at 25°C.
[0029] Prepare wall material solution: Prepare an aqueous solution of carrageenan with a κ type carrageenan content of 1.0 wt% at a temperature of 60°C; prepare an aqueous solution of gelatin with a concentration of 0.5 wt% at a temperature of 50°C; Mix the above carrageenan aqueous solution and gelatin aqueous solution in a solute ratio of gelatin:carrageenan = 0.3:1 by mass to prepare a wall material solution, and control the temperature of the wall material solution at 55-65℃.
[0030] Step 2, droplet preparation The core material slurry and wall material solution were mixed evenly at a dry basis solids mass ratio of 92:8 to obtain a mixed slurry. The mixed slurry, heated to 55-58°C, was then dispersed into uniform droplets using a vibrating nozzle and introduced into a mixed solution of KCl and NaCl. The KCl concentration in the mixed solution was 0.10 wt%, the NaCl concentration was 0.10 wt%, and the temperature of the mixed solution was 35°C.
[0031] Step 3: Cooling and drying Cool the above mixture to 10°C; add to the mixture Concentrated solution, The concentration was adjusted to 0.05 wt%, and the mixture was kept at 10°C for 5 minutes, with gentle stirring during this time to maintain uniform suspension of the droplets. The mixture was then filtered and dried with hot air at 65°C to a moisture content of 10 wt%, yielding microencapsulated feed for aquatic animals. Example 2
[0032] The method for preparing a microencapsulated feed for aquatic animals is as follows: Step 1, Ingredients Preparation of core material slurry: Weigh 16 parts by weight of α-starch, 20 parts by weight of single-cell protein powder, 10 parts by weight of black soldier fly powder, 12 parts by weight of enzymatically hydrolyzed soybean meal, 10 parts by weight of kelp powder, 20 parts by weight of Chlorella, 6 parts by weight of yeast autolysate powder, and 6 parts by weight of spirulina powder. Add water and mix, adjusting the amount of water added to make the mixture contain 24 wt% water. Shear and knead to form a 25 The apparent viscosity is 1000 mPa·s / 25 A uniform core material slurry.
[0033] Prepare wall material solution: Prepare an aqueous solution of carrageenan with a κ type carrageenan content of 2.0 wt% at a temperature of 55℃; prepare an aqueous solution of gelatin with a concentration of 1.5 wt% at a temperature of 60℃.
[0034] Mix the above carrageenan aqueous solution and gelatin aqueous solution at a solute ratio of gelatin:carrageenan = 0.8:1 by mass to prepare a wall material solution, and control the temperature of the wall material solution at 58–65℃.
[0035] Step 2, droplet preparation The core material slurry and wall material solution are mixed at a dry basis solids mass ratio of 99:1 to obtain a mixed slurry. The mixed slurry, at 55–58°C, is then dispersed into uniform droplets in a KCl solution with a concentration of 0.2 wt% and a temperature of 35°C using a vibrating nozzle.
[0036] Step 3: Cooling and drying Cool the above KCl solution to 10°C; add to the KCl solution Concentrated solution, The concentration was adjusted to 0.05 wt%, and the mixture was kept at 10°C for 10 minutes, with gentle stirring during this time to maintain uniform suspension of the droplets. The mixture was then filtered and dried with hot air at 65°C to a moisture content of 9 wt%, yielding microencapsulated feed for aquatic animals. Example 3
[0037] The method for preparing a microencapsulated feed for aquatic animals is as follows: Step 1, Ingredients Preparation of core material slurry: Weigh 18 parts by weight of α-starch, 20 parts by weight of single-cell protein powder, 8 parts by weight of black soldier fly powder, 12 parts by weight of enzymatically hydrolyzed soybean meal, 15 parts by weight of kelp powder, 17 parts by weight of Chlorella, 5 parts by weight of yeast autolysate powder and 5 parts by weight of Spirulina powder, add water and mix, adjust the amount of water added so that the mixture contains 18 wt% water; shear and knead to form a uniform core material slurry with an apparent viscosity of 6000 mPa·s / 25°C at 25°C.
[0038] Prepare wall material solution: Prepare an aqueous solution of carrageenan with a κ type carrageenan content of 3.0 wt% at a temperature of 80℃; prepare an aqueous solution of gelatin with a concentration of 2.5 wt% at a temperature of 65℃.
[0039] Mix the above carrageenan aqueous solution and gelatin aqueous solution in a solute ratio of gelatin:carrageenan = 1.5:1 by mass to prepare a wall material solution, and control the temperature of the wall material solution at 60–65℃.
[0040] Step 2, droplet preparation The core material slurry and wall material solution were mixed thoroughly at a dry basis solids ratio of 95:5 to obtain a mixed slurry. A vibrating nozzle was used to apply the slurry to a concentration of 58-60 kJ / L. The above-mentioned mixed slurry was dispersed into uniform droplets and introduced into a KCl solution with a concentration of 0.8 wt% and a temperature of 45°C. .
[0041] Step 3: Cooling and drying Cool the above KCl solution to 15°C; add to the KCl solution Concentrated solution, The mass concentration was adjusted to 0.1 wt%, and the mixture was kept at 15°C for 15 minutes, with gentle stirring during this time to maintain uniform suspension of the droplets. The mixture was then filtered and fluidized bed dried at 65°C to a moisture content of 9 wt% to obtain microencapsulated feed for aquatic animals.
[0042] Step 4, apply oil The microcapsule feed was placed in a vacuum mixer and vacuumed to -0.08 MPa. While mixing, atomized fish oil was sprayed in at a rate of 3.0 wt% of the microcapsules. After 5 minutes, the pressure was restored to normal and the mixture was stirred for another 5 minutes to wipe off any excess oil from the surface. Example 4
[0043] The method for preparing a microencapsulated feed for aquatic animals is as follows: Step 1, Ingredients Preparation of core material slurry: Weigh 8 parts by weight of α-starch, 8 parts by weight of single-cell protein powder, 10 parts by weight of black soldier fly powder, 12 parts by weight of enzymatically hydrolyzed soybean meal, 30 parts by weight of kelp powder, 20 parts by weight of Chlorella, 6 parts by weight of yeast autolysate powder and 6 parts by weight of Spirulina powder, add water and mix, adjust the amount of water added to make the mixture contain 23 wt% water; shear and knead to form a uniform core material slurry with an apparent viscosity of 2000 mPa·s / 25 °C at 25 °C.
[0044] Prepare wall material solution: Prepare an aqueous solution of carrageenan with a κ type carrageenan content of 2.0 wt% at a temperature of 70°C; prepare an aqueous solution of gelatin with a concentration of 2.0 wt% at a temperature of 50°C.
[0045] Mix the above carrageenan aqueous solution and gelatin aqueous solution in a solute ratio of gelatin:carrageenan = 1.2:1 by mass to prepare a wall material solution, and control the temperature of the wall material solution at 55-60℃.
[0046] Step 2, droplet preparation The core material slurry and wall material solution were mixed at a dry basis solids mass ratio of 93:7 to obtain a mixed slurry. The mixed slurry, at 58–60°C, was dispersed into uniform droplets in a KCl solution with a concentration of 0.6 wt% and a temperature of 38°C using a vibrating nozzle.
[0047] Step 3: Cooling and drying Cool the above KCl solution to 20°C; add to the KCl solution Concentrated solution, The concentration was adjusted to 0.2 wt%, and the mixture was kept at 20°C for 15 minutes, with gentle stirring during this time to maintain uniform suspension of the droplets. The mixture was then filtered and fluidized bed dried at 65°C to a moisture content of 9 wt%, yielding microencapsulated feed for aquatic animals.
[0048] Step 4, apply oil The microcapsule feed was placed in a vacuum mixer and vacuumed to -0.092 MPa. While mixing, atomized fish oil was sprayed in at a rate of 2.0 wt% of the microcapsules. After 5 minutes, the pressure was restored to normal and the mixture was stirred for another 5 minutes to wipe off any excess oil from the surface. Example 5
[0049] The method for preparing a microencapsulated feed for aquatic animals is as follows: Step 1, Ingredients Preparation of core material slurry: Weigh 14 parts by weight of α-starch, 20 parts by weight of single-cell protein powder, 4 parts by weight of black soldier fly powder, 12 parts by weight of enzymatically hydrolyzed soybean meal, 30 parts by weight of kelp powder, 15 parts by weight of Chlorella, 3 parts by weight of yeast autolysate powder, and 2 parts by weight of spirulina powder. Add water and mix, adjusting the amount of water added to make the mixture contain 22 wt% water; shear and knead to form 25 The apparent viscosity is 2500 mPa·s / 25 A uniform core material slurry.
[0050] Prepare wall material solution: Prepare an aqueous solution of carrageenan with a type I carrageenan content of 3.0 wt% and a temperature of 75°C; prepare an aqueous solution of gelatin with a temperature of 60°C and a concentration of 2.0 wt%.
[0051] Mix the above carrageenan aqueous solution and gelatin aqueous solution in a solute ratio of gelatin:carrageenan = 1:1 by mass to prepare a wall material solution, and control the temperature of the wall material solution at 55-60℃.
[0052] Step 2, droplet preparation The core material slurry and wall material solution were mixed thoroughly at a dry basis solids ratio of 94:6 to obtain a mixed slurry. A vibrating nozzle was used to apply 50-53... The above-mentioned mixed slurry was dispersed into uniform droplets and introduced into a KCl solution with a concentration of 0.4 wt% and a temperature of 42°C. .
[0053] Step 3: Cooling and drying Cool the above KCl solution to 10°C; add to the KCl solution Concentrated solution, The concentration was adjusted to 0.15 wt%, and the mixture was kept at 10°C for 5 minutes, with gentle stirring during this time to maintain uniform suspension of the droplets. The mixture was then filtered and fluidized bed dried at 65°C to a moisture content of 7 wt% to obtain microencapsulated feed for aquatic animals.
[0054] Step 4, apply oil The microcapsule feed was placed in a vacuum mixer and vacuumed to -0.095 MPa. While mixing, atomized fish oil was sprayed in at a rate of 4.0 wt% of the microcapsules. After 15 minutes, the pressure was restored to normal and the mixture was stirred for 5 minutes to wipe off any excess oil on the surface. Example 6
[0055] The method for preparing a microencapsulated feed for aquatic animals is as follows: Step 1, Ingredients Preparation of core material slurry: Weigh 18 parts by weight of α-starch, 16 parts by weight of single-cell protein powder, 10 parts by weight of black soldier fly powder, 5 parts by weight of enzymatically hydrolyzed soybean meal, 25 parts by weight of kelp powder, 15 parts by weight of Chlorella, 5 parts by weight of yeast autolysate powder, and 6 parts by weight of spirulina powder. Add water and mix, adjusting the amount of water added to make the mixture contain 23 wt% water. Shear and knead to form 25 wt% slurry. The apparent viscosity is 2000 mPa·s / 25 A uniform core material slurry.
[0056] Prepare wall material solution: Prepare an aqueous solution of carrageenan with a type I carrageenan content of 2.5 wt% and a temperature of 80°C; prepare an aqueous solution of gelatin with a temperature of 65°C and a concentration of 1.0 wt%.
[0057] Mix the above carrageenan aqueous solution and gelatin aqueous solution in a solute ratio of gelatin:carrageenan = 0.5:1 by mass to prepare a wall material solution, and control the temperature of the wall material solution at 55-60℃.
[0058] Step 2, droplet preparation The core material slurry and wall material solution are mixed evenly at a dry basis solids mass ratio of 96:4. The mixed slurry, at 55-60°C, is then dispersed into uniform droplets in a KCl solution using a vibrating nozzle. The KCl solution has a concentration of 0.5 wt% and a temperature of 39°C.
[0059] Step 3: Cooling and drying Cool the above KCl solution to 15°C; add to the KCl solution Concentrated solution, The concentration was adjusted to 0.05 wt%, and the mixture was kept at 15°C for 10 minutes, with gentle stirring during this time to maintain uniform suspension of the droplets. The mixture was then filtered and fluidized bed dried at 65°C to a moisture content of 8 wt% to obtain microencapsulated feed for aquatic animals.
[0060] Step 4, apply oil The microcapsule feed was placed in a vacuum mixer and vacuumed to -0.08 MPa. While mixing, atomized fish oil was sprayed in at a rate of 4.0 wt% of the microcapsules. After 10 minutes, the pressure was restored to normal and the mixture was stirred for 5 minutes to wipe off any excess oil on the surface. Example 7
[0061] The method for preparing a microencapsulated feed for aquatic animals is as follows: Step 1, Ingredients Preparation of core material slurry: Weigh 18 parts by weight of α-starch, 10 parts by weight of single-cell protein powder, 5 parts by weight of black soldier fly powder, 10 parts by weight of enzymatically hydrolyzed soybean meal, 30 parts by weight of kelp powder, 18 parts by weight of Chlorella, 6 parts by weight of yeast autolysate powder, and 3 parts by weight of spirulina powder. Add water and mix, adjusting the amount of water added to make the mixture contain 19 wt% water. Shear and knead to form a 25 The apparent viscosity is 5000 mPa·s / 25 A uniform core material slurry.
[0062] Prepare wall material solution: Prepare an aqueous solution of carrageenan with a type I carrageenan content of 1.5 wt% and a temperature of 55°C; prepare an aqueous solution of gelatin with a concentration of 2.5 wt% and a temperature of 50°C.
[0063] Mix the above carrageenan aqueous solution and gelatin aqueous solution in a solute ratio of gelatin:carrageenan = 1.2:1 by mass to prepare a wall material solution, and control the temperature of the wall material solution at 55-60℃.
[0064] Step 2, droplet preparation The core material slurry and wall material solution are mixed evenly at a dry basis solids mass ratio of 97:3 (core material: wall material). The mixed slurry, at 55-60°C, is then dispersed into uniform droplets in a KCl solution using a vibrating nozzle. The KCl solution has a concentration of 0.8 wt% and a temperature of 40°C.
[0065] Step 3: Cooling and drying Cool the above KCl solution to 10°C; add to the KCl solution Concentrated solution, The concentration was adjusted to 0.1 wt%, and the mixture was kept at 10°C for 15 minutes, with gentle stirring during this time to maintain uniform suspension of the droplets. The mixture was then filtered and fluidized bed dried at 65°C to a moisture content of 8 wt% to obtain microencapsulated feed for aquatic animals.
[0066] Step 4, apply oil The microcapsule feed was placed in a vacuum mixer and vacuumed to -0.06 MPa. While mixing, atomized fish oil was sprayed in at a rate of 3.0 wt% of the microcapsules. After 5 minutes, the pressure was restored to normal and the mixture was stirred for another 5 minutes to wipe off any excess oil from the surface. Example 8
[0067] The method for preparing a microencapsulated feed for aquatic animals is as follows: Step 1, Ingredients Preparation of core material slurry: Weigh 18 parts by weight of α-starch, 20 parts by weight of single-cell protein powder, 10 parts by weight of black soldier fly powder, 6 parts by weight of enzymatically hydrolyzed soybean meal, 24 parts by weight of kelp powder, 8 parts by weight of chlorella, 6 parts by weight of yeast autolysate powder, 6 parts by weight of spirulina powder, and 2 parts by weight of compound vitamin and mineral powder. Add water and mix, adjusting the amount of water added to make the mixture contain 20 wt% water. Shear and knead to form a uniform core material slurry with an apparent viscosity of 4000 mPa·s / 25°C at 25 °C.
[0068] Prepare wall material solution: Prepare an aqueous solution of carrageenan with a type I carrageenan content of 3.0 wt% and a temperature of 80°C; prepare an aqueous solution of gelatin with a temperature of 60°C and a concentration of 1.5 wt%.
[0069] Mix the above carrageenan aqueous solution and gelatin aqueous solution in a solute ratio of gelatin:carrageenan = 1:1 by mass to prepare a wall material solution, and control the temperature of the wall material solution at 55-60℃.
[0070] Step 2, droplet preparation The core material slurry and wall material solution are mixed evenly at a dry basis solids mass ratio of 98:2. The mixed slurry, heated to 55-60°C, is then dispersed into uniform droplets in a KCl solution with a concentration of 0.6 wt% and a temperature of 41°C using a vibrating nozzle.
[0071] Step 3: Cooling and drying Cool the above KCl solution to 15°C; add to the KCl solution Concentrated solution, The concentration was adjusted to 0.2 wt%, and the mixture was kept at 15°C for 5 minutes, with gentle stirring during this time to maintain uniform suspension of the droplets. The mixture was then filtered and fluidized bed dried at 65°C to a moisture content of 9 wt%, yielding microencapsulated feed for aquatic animals.
[0072] Step 4, apply oil The microcapsule feed was placed in a vacuum mixer and vacuumed to -0.08 MPa. While mixing, atomized fish oil was sprayed in at a rate of 2.0 wt% of the microcapsules. After 5 minutes, the pressure was restored to normal and the mixture was stirred for another 5 minutes to wipe off any excess oil on the surface. Example 9
[0073] The method for preparing a microencapsulated feed for aquatic animals is as follows: Step 1, Ingredients Preparation of core material slurry: Weigh 18 parts by weight of α-starch, 20 parts by weight of single-cell protein powder, 10 parts by weight of black soldier fly powder, 10 parts by weight of enzymatically hydrolyzed soybean meal, 18 parts by weight of kelp powder, 10 parts by weight of chlorella, 6 parts by weight of yeast autolysate powder, 6 parts by weight of spirulina powder, and 2 parts by weight of compound vitamin and mineral powder. Add water and mix, adjusting the amount of water added to make the mixture contain 18 wt% water. Shear and knead to form a uniform core material slurry with an apparent viscosity of 6000 mPa·s / 25°C at 25 °C.
[0074] Prepare wall material solution: Prepare an aqueous solution of carrageenan with a type I carrageenan content of 2.5 wt% and a temperature of 70°C; prepare an aqueous solution of gelatin with a temperature of 65°C and a concentration of 0.5 wt%.
[0075] Mix the above carrageenan aqueous solution and gelatin aqueous solution in a solute ratio of gelatin:carrageenan = 0.5:1 by mass to prepare a wall material solution, and control the temperature of the wall material solution at 55-60℃.
[0076] Step 2, droplet preparation The core material slurry and wall material solution are mixed evenly at a dry basis solids mass ratio of 95:5. The mixed slurry, at 58-60°C, is then dispersed into uniform droplets in a KCl solution with a concentration of 0.4 wt% and a temperature of 42°C using a vibrating nozzle.
[0077] Step 3: Cooling and drying The KCl solution was cooled to 20°C; a concentrated CaCl2 solution was added to the KCl solution to bring the CaCl2 concentration to 0.15 wt%, and the mixture was kept at 20°C for 10 minutes, with gentle stirring to maintain uniform suspension of the droplets. The mixture was then filtered and fluidized bed dried at 65°C to a moisture content of 9 wt% to obtain microencapsulated feed for aquatic animals.
[0078] Step 4, apply oil The microcapsule feed was placed in a vacuum mixer and vacuumed to -0.08 MPa. While mixing, atomized fish oil was sprayed in at a rate of 3.0 wt% of the microcapsules. After 5 minutes, the pressure was restored to normal and the mixture was stirred for another 5 minutes to wipe off any excess oil from the surface.
[0079] Comparative Example 1 Prepare a pelleted feed.
[0080] The difference between the preparation method of this comparative example and Example 2 lies in step three. In this comparative example, the temperature of the KCl solution is 5°C, as detailed below: Step 3: Cooling and drying Cool the above KCl solution to 5°C; add to the KCl solution Concentrated solution, The concentration was adjusted to 0.05 wt%, and the mixture was kept at 5°C for 10 minutes, with gentle stirring during this time to maintain uniform suspension of the droplets. The mixture was then filtered and dried with hot air at 65°C until the moisture content was 9 wt%. The other steps were exactly the same as in Example 2, resulting in a pelleted feed.
[0081] Comparative Example 2 Prepare a pelleted feed.
[0082] The difference between the preparation method of this comparative example and Example 2 lies in step three. In this comparative example, the temperature of the KCl solution is 30°C, as detailed below: Step 3: Cooling and drying Cool the above KCl solution to 30°C; add to the KCl solution Concentrated solution, The concentration was adjusted to 0.05 wt%, and the mixture was kept at 30°C for 10 minutes, with gentle stirring during this time to maintain uniform suspension of the droplets. The mixture was then filtered and dried with hot air at 65°C until the moisture content was 9 wt%. The other steps were exactly the same as in Example 2, resulting in a pelleted feed.
[0083] Comparative Example 3 Prepare a pelleted feed.
[0084] The difference between the preparation method of this comparative example and Example 2 lies in step two. In this comparative example, the temperature of the KCl solution into which the droplets enter is 48°C, as detailed below: The core material slurry and wall material solution were mixed evenly at a dry basis solids mass ratio of 99:1 (core material:wall material). The mixed slurry, at 55-58°C, was then dispersed into uniform droplets in a KCl solution with a concentration of 0.5 wt% and a temperature of 48°C using a vibrating nozzle. The other steps were identical to those in Example 2, resulting in a granular feed.
[0085] Comparative Example 4 Prepare a pelleted feed.
[0086] The difference between the preparation method of this comparative example and Example 2 lies in step two. In this comparative example, the temperature of the KCl solution into which the droplets enter is 30°C, as detailed below: The core material slurry and wall material solution were mixed evenly at a dry basis solids mass ratio of 99:1 (core material:wall material). The mixed slurry, at 55-58°C, was then dispersed into uniform droplets in a KCl solution with a concentration of 0.5 wt% and a temperature of 30°C using a vibrating nozzle. The other steps were identical to those in Example 2, resulting in a granular feed.
[0087] Comparative Example 5 Prepare a pelleted feed.
[0088] The difference between the preparation method of this comparative example and Example 2 lies in step one. In this comparative example, the ratio of gelatin and carrageenan used in the prepared wall material solution is different, specifically: Mix the carrageenan aqueous solution and the gelatin aqueous solution in a solute ratio of 0.1:1 by mass to prepare a wall material solution, and control the temperature of the wall material solution at 58-65℃.
[0089] The other steps are exactly the same as in Example 2, resulting in a pelleted feed.
[0090] Comparative Example 6 Prepare a pelleted feed.
[0091] The difference between the preparation method of this comparative example and Example 2 lies in step one. In this comparative example, the ratio of gelatin and carrageenan used in the prepared wall material solution is different, specifically: Mix the carrageenan aqueous solution and the gelatin aqueous solution in a solute ratio of 1.8:1 by mass to prepare a wall material solution, and control the temperature of the wall material solution at 58-65℃.
[0092] The other steps are exactly the same as in Example 2, resulting in a pelleted feed.
[0093] Detection: The feeds obtained from each embodiment and each comparative example were tested, and the test results are recorded in Table 1. The specific test methods are as follows: 1. Particle size distribution: Particle size distribution was determined using a laser diffractometer. A certain amount of microcapsule sample was added to deionized water and uniformly dispersed using ultrasonication under wet dispersion conditions. After the background stabilized, the particle volume distribution was measured and the D value was recorded. 10 D 50 D 90 ; .
[0094] 2. 2 h water stability: Under the condition of 25 ± 1℃, weigh... m 0The microencapsulated feed was added to seawater with a pre-controlled temperature of 25 ± 1℃ and a salinity of 35‰, allowing it to disperse naturally and remain still. After standing for 2 hours without external stirring, all microencapsulated particles were collected from the water using a sieve or filter membrane. After removing surface moisture, the particles were dried at 601℃ to constant weight, and the mass of the resulting particles was measured (denoted as ). ), and The quality retention rate of the microencapsulated feed was calculated and used as a 2-hour water stability index. The results are recorded in Table 1.
[0095] 3. Amino nitrogen dissolution rate: Tested in seawater with a salinity of 35‰ and a temperature of 25 ± 1℃. Weigh... The quality microencapsulated feed was added to seawater with a salinity of 35‰ and a pre-controlled temperature of 25 ± 1℃, allowing it to disperse naturally and remain still. After standing for 2 hours without external stirring, the supernatant was collected, and the amino nitrogen content was determined by colorimetry. The amino nitrogen dissolution rate after 2 hours was calculated using the initial soluble amino nitrogen content of the sample as a reference.
[0096] 4. Suspension half-life T50: Determined under the conditions of seawater with a salinity of 35‰ and a temperature of 25 ± 1℃: Add seawater at a constant temperature of 25 ± 1℃ to a 1 L transparent graduated cylinder and add a quantitative amount of microcapsule sample at one time. After initial uniform dispersion, start timing immediately and allow it to settle. Take supernatant samples at a fixed depth below the liquid surface at multiple time points, filter them through a filter membrane / sieve to recover suspended particles, dry them to constant weight, and weigh them. Calculate the suspension retention rate at each time point. The time corresponding to when the suspension retention rate drops to 50% is T50.
[0097] 5. Shrimp feeding experiment: Shrimp larvae were used as the test subjects and fed the microcapsule feed during their larval stage, when they mainly fed on suspended particles in the water.
[0098] Feed intake was recorded 30 minutes after each feeding to calculate the feed intake rate; Two hours after feeding, water samples were taken from the aquaculture area to determine the total ammonia nitrogen content. The survival rate of shrimp larvae was recorded after 10 days of continuous feeding.
[0099] 6. Breakage rate and pulverization rate The dried microcapsule sample was sieved to obtain particles with a diameter of 160–220 μm, and the mass of the particles was weighed. =50g. The sample was placed in a sealed metal drum with an inner diameter of 50mm and a height of 150mm and rolled at a constant speed of 300rpm for 10–30 min. After removal, it was passed through a 160μm sieve for grading. The mass of particles ≥160μm after rolling was measured. The mass of fine powder passing through a 160 μm sieve is .
[0100] Breakage rate = calculate, Powdering rate = calculate.
[0101] Table 1
[0102] The test results in Table 1 show that: Various embodiments of the preparation of microcapsule feed for aquatic animals using the method of the present invention show that the prepared microcapsule feed for aquatic animals has uniform particle size, is not easily broken or pulverized, has good water stability at 2 hours, low amino nitrogen dissolution, and a long suspension half-life; it results in high feeding rate for shrimp larvae, low ammonia nitrogen in the water, and a high survival rate at 10 days.
[0103] Comparative Example 1, which did not employ the method of this invention, suffered from excessively low and rapid cooling of the salt solution in step three (to 5°C). This resulted in the capsules easily shrinking and releasing water, causing them to break upon immersion in water and failing to form an effective interpenetrating colloidal network shell. Consequently, the feed prepared using this method exhibited a wide particle size distribution, a Span value of 1.143, decreased particle integrity, and high breakage and pulverization rates. The prepared feed also showed poor water stability over 2 hours, significant amino nitrogen dissolution, and a short suspension half-life. When fed to shrimp larvae, it resulted in low feed intake, high ammonia nitrogen levels in the water, and a low 10-day survival rate.
[0104] Comparative Example 2, which did not use the method of this invention, had an excessively high salt solution temperature (30°C) in step three. The feed prepared in this example could not form a dense, continuous, interpenetrating hard shell and a well-structured interpenetrating colloidal network shell in time, resulting in significantly reduced stability in the brine and a tendency to crack in water. The feed exhibited high breakage and pulverization rates, poor water stability after 2 hours, significant amino nitrogen dissolution, and a short suspension half-life. Furthermore, the shrimp larvae had low feeding rates, high ammonia nitrogen levels in the water, and low survival rates after 10 days.
[0105] In Comparative Example 3, which did not employ the method of this invention, the salt solution temperature was too high (48°C) in step two, resulting in droplet co-drip, stringing, and loss of roundness. The feed exhibited high breakage and pulverization rates, uneven particle size, poor water resistance and impermeability of the shell. Table 1 shows poor water stability at 2 hours, significant amino nitrogen dissolution, and a short suspension half-life; low feeding rate among shrimp larvae, high ammonia nitrogen levels in the water, and a low 10-day survival rate.
[0106] Comparative Example 4, which did not use the method of this invention, had a salt solution temperature of 30°C in step two. After the droplets were added, a dense, hard shell would instantly form on the surface, but the internal temperature of the droplets remained high, causing the shell to crack or shrink. This prevented the formation of an interpenetrating colloidal shell, resulting in brittle feed particles and increased pulverization. Table 1 shows that the finished feed had a Span value of 1.519, uneven particle size, poor water stability over 2 hours, significant amino nitrogen dissolution, and a short suspension half-life. The shrimp larvae had low feeding rates, high ammonia nitrogen levels in the water, and low survival rates after 10 days.
[0107] In Comparative Example 5, which did not employ the method of this invention, the ratio of gelatin to carrageenan in the preparation of the wall material solution in step one was too low, i.e., the gelatin content was too low and the carrageenan content was too high. This resulted in insufficient continuity of the interpenetrating colloidal network film formation, leading to a brittle shell with numerous pores in the prepared feed, decreased salt water stability, and increased leakage. Furthermore, the feed exhibited poor water stability over 2 hours, significant amino nitrogen dissolution, and a short suspension half-life. The final feed intake rate of shrimp larvae was low, the ammonia nitrogen level in the water was high, and the survival rate of shrimp larvae after 10 days of feeding was low.
[0108] In Comparative Example 6, which did not employ the method of this invention, the ratio of gelatin to carrageenan was too high during the preparation of the wall material solution in step one, i.e., too much gelatin and too little carrageenan. This resulted in the interpenetrating colloidal network structure easily swelling, decreased salt water stability, and increased leakage. Furthermore, the capsule feed exhibited poor water stability after 2 hours, significant amino nitrogen dissolution, and a short suspension half-life; the shrimp larvae fed this feed had low feeding rates, high ammonia nitrogen levels in the water, and a low survival rate after 10 days of feeding.
[0109] It should be noted that the descriptions of these embodiments are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described above can be combined with each other as long as they do not conflict with each other. In addition, the above are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
Claims
1. A method for preparing a microencapsulated feed for aquatic animals, characterized by, The method comprises the following steps: Step one, ingredient preparation Preparation of core material slurry: mix modified starch and nutrient powder with water to make the mixture contain 18-24 wt% of water; shear knead to form a uniform core material slurry with an apparent viscosity of 1000-6000 mPa·s / 25°C at 25°C; Preparation of wall material solution: Prepare a kappa carrageenan or iota carrageenan aqueous solution with a mass fraction of 55-80°C and 1.0-3.0 wt%; prepare a gelatin aqueous solution with a mass fraction of 0.5-2.5 wt% at a temperature of 50-65°C; Mix the above-mentioned carrageenan aqueous solution and gelatin aqueous solution in a mass ratio of gelatin:carrageenan=0.3-1.5:1 to prepare a wall material solution, and control the temperature of the wall material solution at 55-65°C; Step two, droplet preparation Mix the core material slurry and the wall material solution in a dry solid mass ratio of core material:wall material=92-99:1-8, and prepare droplets under the condition of a temperature of 50-60°C and dispersion into a salt solution; the salt solution is a KCl solution or a mixed solution of KCl and NaCl; the concentration of the solute in the salt solution is 0.2-0.8 wt%, and the mass ratio of NaCl to KCl is 0-1:1; the temperature of the salt solution is 35-45°C; Step three, cooling and drying Cool the above salt solution to 10-20°C; add to the salt solution... Concentrated solution, The mass concentration is adjusted to 0.05-0.20 wt%, and the mixture is kept at 10-20°C for 5-15 min, during which gentle stirring is performed to maintain uniform suspension of the droplets; the mixture is then filtered and dried to obtain microcapsule feed for aquatic animals.
2. The method for preparing microencapsulated feed for aquatic animals as described in claim 1, characterized in that, The method further comprises the following steps: Step four, oiling Oiling the surface of the microcapsules under vacuum, and the oiling amount is 0-4 wt% of the microcapsules; the oil is a feed oil or an edible oil.
3. The method for preparing microencapsulated feed for aquatic animals as described in claim 1, characterized in that, The temperature of the salt solution into which the droplets are prepared in step two is 38-42°C.
4. The method for preparing microencapsulated feed for aquatic animals as described in claim 1, characterized in that, When preparing the wall material solution, mix the carrageenan aqueous solution and the gelatin aqueous solution in a mass ratio of gelatin:carrageenan=0.8-1.2:
1.
5. The method for preparing microencapsulated feed for aquatic animals as described in claim 1, characterized in that, The nutrient powder is single-cell protein powder or a mixture of single-cell protein powder and at least one of black soldier fly powder, kelp powder, enzyme-treated soybean meal powder, algal powder, and yeast autolysis powder.
6. The method for preparing the microcapsule feed for aquatic animals according to any one of claims 1 to 5, wherein The drying in step three is hot air drying or fluidized bed drying at 55-65°C, and the moisture content after drying is ≤10 wt%.
7. A microencapsulated feed for aquatic animals, characterized by, The microcapsules are prepared by the method of any one of claims 1-6.
8. The microencapsulated feed of aquatic animals according to claim 7, wherein the microcapsule is prepared by using a wall material selected from the group consisting of gelatin, starch, cellulose, chitin, chitosan, and derivatives thereof. The density of the microcapsules is 0.9-1.05 g / cm³.
9. The microencapsulated feed of claim 7, wherein the microcapsules are coated with a material selected from the group consisting of gelatin, casein, albumin, and combinations thereof. Its particle size D 50 It is 160-220 μm.
10. The microencapsulated feed of claim 7, wherein the microcapsules are coated with a material selected from the group consisting of gelatin, casein, albumin, and combinations thereof. The particle size distribution of the microcapsules satisfies a particle size distribution width Span≤0.8.