Feed additive using feather hydrolysate and preparation method thereof

Abstract

The invention belongs to the technical field of biology, and particularly relates to a feed additive using feather hydrolysate and a preparation method thereof, and the preparation method comprises the following steps: (1) raw material pretreatment; (2) starch solidification; (3) fine crushing; step (4) cooking treatment; (5) performing enzymolysis; and (6) post-treatment: carrying out enzyme deactivation, solid-liquid separation, filtrate concentration and spray drying to prepare a composite hydrolysate, and then adding auxiliary materials to prepare the feed additive using the feather hydrolysate. According to the scheme, a physical brittle matrix is constructed, mechanical force and hydrothermal action are cooperated, deep and uniform pre-destruction of a supramolecular structure of feather keratin is realized in a low-cost and high-efficiency manner, and an ideal reaction substrate is created for subsequent specific enzymolysis, so that on the premise that the integrity of target amino acid is guaranteed, the yield of the feather keratin is increased, and the yield of the feather keratin is increased. The efficient conversion of the feather protein and the preparation of a high-quality product are realized.

Description

Technical Field

[0001] The invention belongs to the field of biotechnology, and in particular relates to a feed additive utilizing feather hydrolysate and a preparation method thereof. Background Art

[0002] Against the backdrop of the global livestock industry's massive growth, a vast amount of discarded feathers are generated annually. These feathers, primarily composed of keratin and containing over 85% protein, represent a potential source of high-quality protein. Converting this waste biomass into high-value-added amino acids for feed not only effectively alleviates the pressure on the supply of feed protein raw materials but also aligns with the industry's commitment to a circular economy and sustainable development, thus possessing significant economic and social significance.

[0003] Currently, the mainstream technological approach to feather resource utilization revolves around efficiently and gently deconstructing the exceptionally robust keratin macromolecular structure. Keratin molecules possess a dense, dense β-pleated structure, further locked in place by a dense network of disulfide and hydrogen bonds. This creates extreme chemical inertness and physical toughness, a key obstacle to their resource utilization. To overcome this obstacle, those skilled in the art have developed a variety of hydrolysis techniques. Chemical hydrolysis, particularly strong acid or base hydrolysis, is a classic process. Its fundamental principle is to utilize the corrosive action of strong chemical reagents under high temperature and pressure to forcibly sever peptide and disulfide bonds, thereby depolymerizing keratin. This method gained application during a specific historical period due to its rapid processing speed and minimal raw material pretreatment requirements. However, with increasing understanding of product quality, nutritional value, and environmental impact, the inherent shortcomings of chemical hydrolysis have become increasingly apparent. The severity of the reaction conditions not only indiscriminately attacks peptide bonds, but also leads to serious damage to a variety of essential amino acids. For example, the destruction rate of tryptophan can exceed 95%, and the loss rate of sulfur-containing amino acids such as cystine and methionine is as high as 30% to 50%. More seriously, non-specific chemical reactions will give rise to a series of harmful by-products, such as potentially toxic lysalanine and furan compounds, which significantly reduce the feeding safety of the final product. In addition, the system must be neutralized after the reaction, and the large amount of inorganic salts introduced thereby causes the ash content of the product to be as high as 20-35wt%. High salt content not only affects the palatability of the feed, but also increases the metabolic burden on animals. If desalination is subsequently carried out by means such as electrodialysis, the production cost will be significantly increased, limiting the feasibility of its large-scale promotion.

[0004] To circumvent the aforementioned drawbacks of chemical methods, research has shifted to physical assistance and bio-enzymatic hydrolysis. Physical methods such as microwave-assisted hydrolysis utilize microwave energy to selectively stimulate high-frequency vibrations in water molecules within and around feathers, generating localized high temperature and high pressure to disrupt the keratin structure. However, a fundamental limitation of these methods lies in the non-uniformity of energy transfer. In industrial production, large volumes of feather material pile up to create a significant "cold center" effect. Physical limitations on microwave penetration lead to significant temperature differences between the inside and outside of the material. The exterior may be over-hydrolyzed, while the interior is less than 50% hydrolyzed. This ultimately results in an uneven degree of hydrolysis, low free amino acid yield, and a broad molecular weight distribution, making it difficult to meet the requirements of feed additives for component uniformity and high bioavailability.

[0005] In contrast, enzymatic hydrolysis is considered the most promising green technology due to its mild reaction conditions, high specificity, and pure products. This method utilizes specific keratinase enzymes to cleave peptide bonds at specific locations under suitably mild conditions (e.g., neutral pH, 50-60°C). However, the industrialization of this method has been hampered by a fundamental contradiction: the sharp conflict between keratin's physical barrier effect and the accessibility of the enzymatic reaction. Without effective pretreatment, the dense, hydrophobic supramolecular structure of feathers acts as a fortress, making it difficult for keratinase molecules in the aqueous environment to penetrate and reach the active sites within. While conventional mechanical pulverization can increase the specific surface area, the feathers' exceptional toughness makes pulverization energy-intensive and difficult to achieve a sufficiently fine particle size. This results in extremely slow enzymatic hydrolysis reactions. Even after prolonged hydrolysis, protein dissolution rates are often less than 40%, resulting in poor economic efficiency. To address this pretreatment bottleneck, the industry has explored cutting-edge technologies such as plasma and nanomaterial-assisted hydrolysis, but these methods are mostly limited to surface modification and fail to achieve deep damage to the feather's bulk structure. Although ultrafine grinding technology can reduce the particle size to the micron level, it requires extreme conditions such as liquid nitrogen deep freezing to overcome the toughness of feathers. The high cost makes this path economically unsuitable.

[0006] In summary, existing feather hydrolysis technologies are generally caught in a dilemma: the pursuit of efficient and thorough structural destruction is inevitably accompanied by severe degradation and secondary pollution of the target amino acids; while the pursuit of mild and preservative reaction conditions cannot effectively overcome the natural structural stubbornness of keratin, resulting in low reaction efficiency and high costs. This irreconcilable contradiction between "destruction" and "preservation" is the deep technical root that restricts the high-value utilization of feathers. Therefore, how to develop a new method that can not only achieve deep and uniform pretreatment of the dense structure of feathers in a low-cost and high-efficiency manner, but also create ideal reaction conditions for subsequent mild enzymatic hydrolysis, thereby synergistically achieving efficient degradation of keratin and high-fidelity recovery of target amino acids, has become a key challenge currently faced by those skilled in the art and a technical problem that needs to be solved urgently. Summary of the Invention

[0007] The present invention aims to overcome the inherent contradiction between destructive hydrolysis and mild hydrolysis in the prior art: brute force hydrolysis methods lead to severe amino acid degradation and secondary contamination, while mild enzymatic hydrolysis methods suffer from low efficiency due to the physical barrier effect of keratin. To achieve this goal, the present invention provides a feed additive utilizing feather hydrolysate and a method for its preparation. By constructing a physically brittle matrix, the additive synergizes mechanical forces with hydrothermal action to achieve deep and uniform pre-destruction of the feather keratin supramolecular structure in a low-cost, high-efficiency manner. This creates an ideal reaction substrate for subsequent specific enzymatic hydrolysis, thereby achieving efficient conversion of feather protein and the production of a high-quality product while ensuring the integrity of the target amino acids.

[0008] To achieve the above object, the technical solution of the present invention is: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers are immediately frozen after cleaning, roller-pressed, and coarsely crushed into 1-10 mm fragments; Step (2) starch solidification: Feather fragments and starch are mixed at a dry weight ratio of 1:1.2-1.8, water is added to adjust the moisture content to 35-45%, steam gelatinization (90-100°C, 5-15 minutes), and drying and solidification is performed to a moisture content of 8-12%; Step (3) fine grinding: grinding the solidified material into 40-100 mesh (0.15-0.42 mm); Step (4) steaming treatment: steaming at 0.25-0.35 MPa and 120-130° C. for 10-20 min; Step (5) Enzymatic hydrolysis: adding amylase and keratinase to the cooked material, and hydrolyzing at 50-60°C and pH 6.0-7.5 for 4-8 hours; Step (6) post-treatment: enzyme inactivation, solid-liquid separation, filtrate concentration, spray drying to obtain a composite hydrolyzate, which is then added with auxiliary materials to obtain a feed additive using the feather hydrolyzate.

[0009] The core innovation of this preparation method lies in overcoming the bottleneck of feather processing through starch-mediated phase transition embrittlement. Feathers are immediately frozen after cleaning. Rolling is necessary because the feather trunk is thick. Freezing reduces its toughness by freezing water, which then freezes. Rolling fractures the trunk, facilitating subsequent starch penetration and promoting solidification and crushing. The continuous gel network formed by starch gelatinization, when controllably dehydrated to a moisture content of 8-12%, achieves a precise balance between a rigid skeleton and residual plasticity. Low moisture levels (<8%) induce remodeling of keratin β-sheet chains, leading to a restoration of feather fiber toughness; high moisture levels (>12%) leave residual viscoelasticity in the starch matrix, both of which degrade crushing efficiency. Within this critical range, the three-dimensional brittle skeleton constructed by retrograded amylose crystals dominates, locking the feather fibers into a discrete reinforcing phase, resulting in ceramic-like fracture properties. When crushing stress is applied, cracks preferentially propagate along the brittle starch phase and through the feather-starch interface, causing the fibers to cleave and dissociate rather than stretch and entangle. The micron-sized starch particles generated simultaneously form a fluid lubrication layer on the walls of the equipment cavity, preventing fiber adhesion and promoting material flow. Combined with the particle size homogenization effect brought about by rigid constraints, the risk of screen clogging is completely avoided. This physical transformation also enhances the palatability of the final product. The reducing sugars generated by starch enzymatic hydrolysis activate animal sweet receptors, creating a synergistic effect between the amino acid nutrient package and the flavor enhancer at the molecular level.

[0010] Preferably, the starch in step (2) is at least one of corn starch, tapioca starch or wheat starch; and the water vapor pressure during gelatinization is 0.1-0.2 MPa.

[0011] Preferably, the method is characterized in that, in step (5), the amount of amylase added is 5-15 U / g dry weight of starch, and the amount of keratinase added is 800-2000 U / g dry weight of feather protein; the amylase and keratinase are added simultaneously; the amylase is a high-temperature resistant α-amylase (optimum temperature 90-95°C), and the keratinase is a keratinase derived from Bacillus subtilis (optimum temperature 55-65°C).

[0012] Preferably, the drying and curing process is as follows: a) Initial drying: 80℃ hot air (wind speed 2m / s) drying to a moisture content of 18-20%; b) Final drying: vacuum drying at 45°C (-0.08MPa) to a moisture content of 8-12%.

[0013] This drying process utilizes a gradient dehydration strategy to mitigate the uncontrolled phase transitions caused by continuous hot air drying. Initially, 80°C hot air rapidly removes free water, allowing the starch gel network to initially solidify. At this point, a moisture content of 18-20% maintains sufficient plasticity to prevent stress cracking. The final stage, a transition to a 45°C vacuum environment, achieves critical phase transition control. This low-pressure environment reduces the enthalpy of water evaporation, encouraging the gentle migration of bound water below the keratin glass transition temperature (Tg≈50°C). This suppresses the toughness rebound caused by β-sheet chain reconstruction and prevents the premature consumption of reducing sugars by the Maillard reaction induced by high temperatures. The inherent drawbacks of continuous hot air drying are: a single high-temperature field causes the material surface to harden, forming a vapor pressure barrier. This hinders internal moisture evaporation, generating expansion stress and causing delamination at the feather-starch interface. Simultaneously, hot air convection forces the feather fibers to align along the airflow direction, inducing anisotropic shrinkage and forming a network of microcracks in the starch matrix. These pre-existing defects act as stress concentration sources during pulverization, leading to uncontrolled material pulverization and a discrete particle size distribution, significantly increasing the difficulty of subsequent solid-liquid separation of the enzymatic hydrolyzate. Staged drying, through the decoupled control of temperature, pressure, and mass transfer rate, keeps the moisture gradient below the critical fracture toughness, ensuring that the material enters the pulverization stage in an intrinsically brittle state, achieving a fundamental shift in fracture mode from fiber extraction to overall brittle fracture.

[0014] Preferably, the solid-liquid separation in step (6) is carried out by centrifugation at 3000-5000 rpm for 10-20 min, and the filter residue has a water content of ≤40 wt%, which is used as an organic fertilizer raw material.

[0015] Preferably, the concentration in step (6) is carried out by reverse osmosis membrane concentration with an operating pressure of 1.5-3.0 MPa to increase the concentration to 20-30 wt%.

[0016] Preferably, the spray drying parameters in step (6) are: inlet air temperature 160-180°C, outlet air temperature 70-85°C, and material flow rate 20-40 L / h.

[0017] Preferably, the enzyme inactivation parameters in step (6) are as follows: heating the enzymatically hydrolyzed material to 80-85° C. and maintaining the temperature for 10-15 minutes.

[0018] Preferably, the feed additive using feather hydrolysate comprises, by weight, 60-85 parts by weight of the composite hydrolysate, 0.5-2 parts of an anti-caking agent, and 0.1-0.5 parts of an antioxidant.

[0019] The anti-caking agent is selected from at least one of silicon dioxide and calcium phosphate; and the antioxidant is ethoxyquinoline or 2,6-di-tert-butyl-p-cresol (BHT).

[0020] This solution also discloses a feed additive using feather hydrolysate prepared by using the above-mentioned method for preparing a feed additive using feather hydrolysate.

[0021] Compared with existing technologies, the advantages of this solution are: This solution overturns the traditional feather processing model through a three-step linkage process: starch phase change embrittlement, steam-directed bond breaking, and dual-enzyme synergistic conversion. The rigid network formed by starch gelatinization transforms feather fibers into a "brittle composite material" at a critical moisture content of 8-12%, breaking the energy consumption bottleneck of ultrafine grinding. Steam promotes the cleavage of disulfide bonds, avoiding the destructive damage of amino acids by strong acids and bases. In the dual-enzyme step-by-step hydrolysis strategy, amylase first removes the coating barrier, while keratinase digests the peptides. The final product integrates feather-derived sulfur-containing amino acids and starch-based reducing sugars, which can improve palatability. The waste residue can be used to make organic fertilizer, eliminating waste generation. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Overall embodiment: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: After cleaning, the feathers were immediately frozen at -10°C, and the main trunks of the feathers were crushed by rollers to coarsely crush them into fragments of 1-10 mm; Step (2) starch solidification: Feather fragments are mixed with starch at a dry weight ratio of 1:1.2-1.8, water is added to adjust the moisture content to 35-45%, steam gelatinization is carried out at 90-100°C for 5-15 minutes, and drying and solidification is carried out to a moisture content of 8-12%; the starch is at least one of corn starch, tapioca starch or wheat starch; the water vapor pressure during gelatinization is 0.1-0.2 MPa; The drying and curing process is: a) Initial drying: 80℃ hot air (wind speed 2m / s) drying to a moisture content of 18-20%; b) Final drying: vacuum drying at 45°C (-0.08MPa) to a moisture content of 8-12%; Step (3) fine grinding: grinding the solidified material into 40-100 mesh (0.15-0.42 mm); Step (4) steaming treatment: steaming at 0.25-0.35 MPa and 120-130° C. for 10-20 min; Step (5) Enzymatic hydrolysis: adding amylase and keratinase to the cooked material, and hydrolyzing at 50-60° C. and pH 6.0-7.5 for 4-8 hours; in step (5), the amount of amylase added is 5-15 U / g dry weight of starch, and the amount of keratinase added is 800-2000 U / g dry weight of feather protein; the amylase and keratinase are added simultaneously; the amylase is a thermostable α-amylase, and the keratinase is a keratinase derived from Bacillus subtilis; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 80-85°C and maintain for 10-15 minutes, separate the solid and liquid at 3000-5000 rpm for 10-20 minutes, concentrate the filtrate through a reverse osmosis membrane at an operating pressure of 1.5-3.0 MPa, increase the concentration to 20-30 wt%, spray dry under conditions of an inlet air temperature of 160-180°C, an outlet air temperature of 70-85°C, and a material flow rate of 20-40 L / h to obtain a composite hydrolyzate, and then add auxiliary materials to obtain a feed additive using the feather hydrolyzate; The prepared feed additive using feather hydrolysate comprises, by weight, 60-85 parts of composite hydrolysate, 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.1-0.5 parts of ethoxyquinoline or BHT.

[0024] Example 1: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers into 5 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch in a dry weight ratio of 1:1.5, water was added to adjust the moisture content to 40%, and steam gelatinized at 95°C for 10 minutes, with a water vapor pressure of 0.15 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: drying at 80°C with a hot air velocity of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa to a moisture content of 10%; Step (3) fine grinding: grinding the solidified material into 100 mesh; Step (4) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 25 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0025] Example 2:

[0026] A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: After cleaning, the feathers were immediately frozen at -10°C, and the main trunks of the feathers were crushed by rollers to coarsely crush them into 3 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with cassava starch in a dry weight ratio of 1:1.2, water was added to adjust the moisture content to 35%, and steam gelatinized at 90°C for 15 minutes, with a water vapor pressure of 0.1 MPa during gelatinization; the drying and solidification process was as follows: a) initial drying: 80°C hot air speed 2m / s drying to a moisture content of 18%; b) final drying: 45°C vacuum drying at a vacuum degree of -0.08MPa to a moisture content of 8%; Step (3) fine grinding: grinding the solidified material into 40 mesh; Step (4) steaming treatment: steaming at 0.25 MPa and 120° C. for 20 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 5 U / g dry weight of starch and the amount of keratinase added being 800 U / g dry weight of feather protein, and hydrolyzing at 50°C and pH 6.0 for 8 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 80°C and maintain for 15 minutes, perform solid-liquid separation by centrifugation at 3000 rpm for 20 minutes, concentrate the filtrate to 20 wt% by reverse osmosis membrane concentration at an operating pressure of 1.5 MPa, and spray dry at an inlet air temperature of 160°C, an outlet air temperature of 70°C, and a material flow rate of 20 L / h to obtain a composite hydrolyzate; and take 60 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.1 part of BHT to prepare a feed additive using feather hydrolyzate.

[0027] Example 3:

[0028] A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers to coarsely crush them into 8 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with wheat starch in a dry weight ratio of 1:1.8, water was added to adjust the moisture content to 45%, and steam gelatinized at 100°C for 5 minutes, with a water vapor pressure of 0.2 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: 80°C hot air speed 2m / s drying to a moisture content of 20%; b) final drying: 45°C vacuum drying at a vacuum degree of -0.08MPa to a moisture content of 12%; Step (3) fine grinding: grinding the solidified material into 100 mesh; Step (4) steaming treatment: steaming at 0.35 MPa and 130° C. for 10 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 15 U / g dry weight of starch and the amount of keratinase added being 2000 U / g dry weight of feather protein, and hydrolyzing at 60°C and pH 7.5 for 4 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 85°C and maintain for 10 minutes, perform solid-liquid separation by centrifugation at 5000 rpm for 10 minutes, concentrate the filtrate to 30 wt% by reverse osmosis membrane concentration at an operating pressure of 3.0 MPa, spray dry at an inlet air temperature of 180°C, an outlet air temperature of 85°C, and a material flow rate of 40 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.5 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0029] Example 4:

[0030] A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers to coarsely crush them into 1 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch in a dry weight ratio of 1:1.3, water was added to adjust the moisture content to 37%, and steam gelatinized at 92°C for 12 minutes, with a water vapor pressure of 0.12 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: 80°C hot air speed 2 m / s drying to a moisture content of 18.5%; b) final drying: 45°C vacuum drying at a vacuum degree of -0.08 MPa to a moisture content of 9%; Step (3) fine grinding: grinding the solidified material into 50 mesh; Step (4) steaming treatment: steaming at 0.28 MPa and 122°C for 18 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 8 U / g dry weight of starch and the amount of keratinase added being 1000 U / g dry weight of feather protein, and hydrolyzing at 52°C and pH 6.3 for 7 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 81°C and maintain for 14 minutes, perform solid-liquid separation by centrifugation at 3500 rpm for 18 minutes, concentrate the filtrate to 22 wt% by reverse osmosis membrane concentration at an operating pressure of 2.2 MPa, and spray dry at an inlet air temperature of 165°C, an outlet air temperature of 72°C, and a material flow rate of 25 L / h to obtain a composite hydrolyzate; take 70 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.2 part of BHT to prepare a feed additive using feather hydrolyzate.

[0031] Example 5:

[0032] A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: After cleaning, the feathers were immediately frozen at -10°C, and the main trunks of the feathers were crushed by rollers to coarsely crush them into 10 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with cassava starch in a dry weight ratio of 1:1.6, water was added to adjust the moisture content to 42%, and steam gelatinized at 98°C for 8 minutes, with a water vapor pressure of 0.18 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: 80°C hot air speed 2 m / s drying to a moisture content of 19.5%; b) final drying: 45°C vacuum drying at a vacuum degree of -0.08 MPa to a moisture content of 11%; Step (3) fine grinding: grinding the solidified material into 80 mesh; Step (4) steaming treatment: steaming at 0.32 MPa and 128° C. for 12 min; Step (5) Enzymatic hydrolysis: Add thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 12 U / g dry weight of starch and the amount of keratinase added being 1800 U / g dry weight of feather protein, and hydrolyze at 58°C and pH 7.2 for 5 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 83°C and maintain for 11 minutes, perform solid-liquid separation by centrifugation at 4500 rpm for 12 minutes, concentrate the filtrate to 28 wt% by reverse osmosis membrane concentration at an operating pressure of 2.5 MPa, and spray dry at an inlet air temperature of 175°C, an outlet air temperature of 80°C, and a material flow rate of 35 L / h to obtain a composite hydrolyzate; take 75 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.4 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0033] Comparative Example 1: The difference from Example 1 is that starch curing is not used: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers into 5 mm fragments; Step (2) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (3) Enzymatic hydrolysis: add Bacillus subtilis-derived keratinase to the cooked material at a rate of 1500 U / g dry weight of feather protein, and hydrolyze at 55°C and pH 6.8 for 6 h; Step (4) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 25 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain feather hydrolyzed amino acids; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using the feather hydrolyzate.

[0034] Comparative Example 2: The difference from Example 1 is that pure hot air curing: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers into 5 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch at a dry weight ratio of 1:1.5, water was added to adjust the moisture content to 40%, and steam gelatinized at 95°C for 10 minutes, with a water vapor pressure of 0.15 MPa during gelatinization. The drying and solidification process was as follows: a) Initial drying: 80°C hot air at a wind speed of 2 m / s to a moisture content of 10%; Step (3) fine grinding: grinding the solidified material into 100 mesh; Step (4) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 25 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0035] Comparative Example 3: The difference from Example 1 is that the feather fragments and corn starch are mixed at a dry weight ratio of 1:2, and water is added to adjust the moisture content to 30%: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers into 5 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch in a dry weight ratio of 1:2, water was added to adjust the moisture content to 30%, and steam gelatinized at 95°C for 10 minutes, with a water vapor pressure of 0.15 MPa during gelatinization; the drying and solidification process was as follows: a) initial drying: 80°C hot air speed 2m / s drying to a moisture content of 19%; b) final drying: 45°C vacuum drying at a vacuum degree of -0.08MPa to a moisture content of 10%; Step (3) fine grinding: grinding the solidified material into 100 mesh; Step (4) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 25 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0036] Comparative Example 4: The difference from Example 1 is that after drying and curing, the moisture content is too high: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers into 5 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch in a dry weight ratio of 1:1.5, water was added to adjust the moisture content to 40%, and steam gelatinized at 95°C for 10 minutes, with a water vapor pressure of 0.15 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: drying at 80°C with a hot air velocity of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa to a moisture content of 15%; Step (3) fine grinding: grinding the solidified material into 100 mesh; Step (4) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 25 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0037] Comparative Example 5: The difference from Example 1 is that after drying and curing, the moisture content is too low: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers into 5 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch in a dry weight ratio of 1:1.5, water was added to adjust the moisture content to 40%, and steam gelatinized at 95°C for 10 minutes, with a water vapor pressure of 0.15 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: drying at 80°C with a hot air velocity of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa to a moisture content of 5%; Step (3) fine grinding: grinding the solidified material into 100 mesh; Step (4) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 25 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0038] Comparative Example 6: The difference from Example 1 is that cooling and solidification are adopted, and the moisture content is 22%: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers into 5 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch at a dry weight ratio of 1:1.5, water was added to adjust the moisture content to 40%, and steam gelatinized at 95°C for 10 min. The steam pressure during gelatinization was 0.15 MPa. After cooling and solidification, the moisture content was 22%; Step (3) fine grinding: grinding the solidified material into 100 mesh; Step (4) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 25 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0039] Comparative Example 7: The difference from Example 1 is that the solidified material is crushed to 20 mesh: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers into 5 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch in a dry weight ratio of 1:1.5, water was added to adjust the moisture content to 40%, and steam gelatinized at 95°C for 10 minutes, with a water vapor pressure of 0.15 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: drying at 80°C with a hot air velocity of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa to a moisture content of 10%; Step (3) fine grinding: grinding the solidified material into 20 mesh; Step (4) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 25 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0040] Comparative Example 8: The difference from Example 1 is that the cooking process in step (4) is not performed: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: After cleaning, the feathers were immediately frozen at -10°C, and the main stems of the feathers were crushed by rollers to coarsely crush them into 5 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch in a dry weight ratio of 1:1.5, water was added to adjust the moisture content to 40%, and steam gelatinized at 95°C for 10 minutes, with a water vapor pressure of 0.15 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: drying at 80°C with a hot air velocity of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa to a moisture content of 10%; Step (3) fine grinding: grinding the solidified material into 100 mesh; Step (4) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (5) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 25 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using the feather hydrolyzate.

[0041] Comparative Example 9: The difference from Example 1 is that the enzyme is not inactivated: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers into 5 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch in a dry weight ratio of 1:1.5, water was added to adjust the moisture content to 40%, and steam gelatinized at 95°C for 10 minutes, with a water vapor pressure of 0.15 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: drying at 80°C with a hot air velocity of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa to a moisture content of 10%; Step (3) fine grinding: grinding the solidified material into 100 mesh; Step (4) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (6) post-treatment: solid-liquid separation by centrifugation at 4000 rpm for 15 min, the filtrate was concentrated to 25 wt% by reverse osmosis membrane concentration operating pressure of 2.0 MPa, and spray drying was performed at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; 85 parts by weight of the composite hydrolyzate were added with 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to obtain a feed additive using the feather hydrolyzate.

[0042] Comparative Example 10: The difference from Example 1 is that the concentration after concentration in step (6) is 35%: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers into 5 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch in a dry weight ratio of 1:1.5, water was added to adjust the moisture content to 40%, and steam gelatinized at 95°C for 10 minutes, with a water vapor pressure of 0.15 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: drying at 80°C with a hot air velocity of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa to a moisture content of 10%; Step (3) fine grinding: grinding the solidified material into 100 mesh; Step (4) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 35 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0043] Comparative Example 11: The difference from Example 1 is that the powder is crushed to a particle size of 120 mesh: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers were immediately frozen at -10°C after cleaning, and the main stems of the feathers were crushed by rollers into 5 mm fragments; Step (2) Starch solidification: Feather fragments were mixed with corn starch in a dry weight ratio of 1:1.5, water was added to adjust the moisture content to 40%, and steam gelatinized at 95°C for 10 minutes, with a water vapor pressure of 0.15 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: drying at 80°C with a hot air velocity of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa to a moisture content of 10%; Step (3) fine grinding: grinding the solidified material into 120 mesh; Step (4) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 25 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0044] Comparative Example 12: The difference from Example 1 is that it is not frozen and rolled: A method for preparing a feed additive using feather hydrolysate comprises the following steps: Step (1) Raw material pretreatment: Feathers are cleaned and coarsely crushed into 5 mm pieces; Step (2) Starch solidification: Feather fragments were mixed with corn starch in a dry weight ratio of 1:1.5, water was added to adjust the moisture content to 40%, and steam gelatinized at 95°C for 10 minutes, with a water vapor pressure of 0.15 MPa during gelatinization. The drying and solidification process was as follows: a) initial drying: drying at 80°C with a hot air velocity of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa to a moisture content of 10%; Step (3) fine grinding: grinding the solidified material into 120 mesh; Step (4) steaming treatment: steaming at 0.3 MPa and 125°C for 15 min; Step (5) Enzymatic hydrolysis: Adding thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with the amount of amylase added being 10 U / g dry weight of starch and the amount of keratinase added being 1500 U / g dry weight of feather protein, and hydrolyzing at 55°C and pH 6.8 for 6 h; Step (6) post-treatment: inactivate the enzyme, raise the temperature to 82°C and maintain for 12 minutes, perform solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate to 25 wt% by reverse osmosis membrane concentration at an operating pressure of 2.0 MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolyzate; take 85 parts by weight of the composite hydrolyzate, add 1 part of silicon dioxide, 1 part of calcium phosphate, and 0.3 part of ethoxyquinoline to prepare a feed additive using feather hydrolyzate.

[0045] Detection method: Raw material utilization rate: 100% - dry weight of filter residue / (dry weight of feathers + dry weight of starch) × 100%; Since no impurities are added in this plan, starch hydrolyzate is sugar, which is also one of the conventional feed additives, so the raw material utilization rate is the simplest yield calculation.

[0046] Total amino acid content: 10 g of the prepared feed additive using feather hydrolysate was dissolved in 1000 g of water and analyzed using an automatic amino acid analyzer. The total amino acid content was also compared with the total amino acid content of commercially available feed additives using feather hydrolysate. The experimental process and results are shown in Table 1.

[0047] Table 1 Experimental process and results of examples and comparative examples

[0048] The feed additive preparation process using feather hydrolysate, constructed in this embodiment of the present invention, achieves technological breakthroughs while demonstrating remarkable simplicity and industrial adaptability. Its core innovation lies in achieving efficient conversion through process logic reconfiguration, rather than equipment replacement, based on a conventional equipment chain. Raw material pretreatment utilizes common chilled roller pressing and mixing equipment. The starch solidification stage directly utilizes a conditioner, commonly used in the feed industry, for gelatinization. The gradient drying process (80°C hot air + 45°C vacuum) is fully compatible with the drying tower parameters of existing feed production lines. Subsequent unit operations, including cooking, enzymatic hydrolysis, centrifugation, and spray drying, seamlessly integrate with standard industrial feed additive production lines, eliminating the need for specialized equipment or pipeline modifications. This design allows for rapid implementation of the technology upgrade in existing feed factories by simply adjusting process parameters (such as controlling starch moisture content to 8-12% and cooking pressure to 0.25-0.35 MPa), significantly lowering the barrier to industrialization. What is particularly critical is that this process uses the starch-mediated phase change embrittlement effect to replace high-energy-consuming complex pretreatment methods such as ultrafine grinding or plasma treatment with a low-cost solution. While ensuring a 92.5% raw material utilization rate and an amino acid yield of 48.2g / 100g, it improves the efficiency of traditional enzymatic hydrolysis. There is no strong acid / alkali neutralization step in the entire process, and the waste residue can also be used to produce inorganic fertilizers.

Claims

1. A method for preparing a feed additive using feather hydrolysate, characterized in that: The following steps are involved: Step (1) Raw material pretreatment: Feathers are immediately frozen after cleaning, roller-pressed, and coarsely crushed into 1-10 mm fragments; Step (2) starch solidification: Feather fragments and starch are mixed at a dry weight ratio of 1:1.2-1.8, water is added to adjust the moisture content to 35-45%, steam gelatinization is carried out, and drying and solidification is carried out to a moisture content of 8-12%; Step (3) fine grinding: grinding the solidified material into 40-100 mesh; Step (4) steaming treatment: steaming at 0.25-0.35 MPa and 120-130° C. for 10-20 min; Step (5) Enzymatic hydrolysis: adding amylase and keratinase to the cooked material, and hydrolyzing at 50-60°C and pH 6.0-7.5 for 4-8 hours; Step (6) post-treatment: enzyme inactivation, solid-liquid separation, filtrate concentration, spray drying to obtain a composite hydrolysate; and a feed additive using feather hydrolysate is prepared by combining 60-85 parts by weight of the composite hydrolysate, 0.5-2 parts of an anti-caking agent, and 0.1-0.5 parts of an antioxidant.

2. The method for preparing a feed additive using feather hydrolysate according to claim 1, characterized in that: The starch in step (2) is at least one of corn starch, tapioca starch or wheat starch; and the water vapor pressure during gelatinization is 0.1-0.2 MPa.

3. The method for preparing a feed additive using feather hydrolysate according to claim 1, characterized in that: In step (5), the amount of amylase added is 5-15 U / g dry weight of starch, and the amount of keratinase added is 800-2000 U / g dry weight of feather protein; the amylase and keratinase are added simultaneously; the amylase is a high-temperature resistant α-amylase, and the keratinase is a keratinase derived from Bacillus subtilis.

4. The method for preparing a feed additive using feather hydrolysate according to claim 1, wherein: The drying and curing process is: a) Initial drying: 80℃ hot air drying to a moisture content of 18-20%; b) Final drying: vacuum drying at 45°C to a moisture content of 8-12%.

5. The method for preparing a feed additive using feather hydrolysate according to claim 1, wherein: In step (6), solid-liquid separation is performed by centrifugation.

6. The method for preparing a feed additive using feather hydrolysate according to claim 1, characterized in that: Step (6) is concentrated by reverse osmosis membrane concentration to increase the concentration to 20-30wt%.

7. The method for preparing a feed additive using feather hydrolysate according to claim 1, characterized in that: The spray drying parameters of step (6) are: inlet air temperature 160-180°C, outlet air temperature 70-85°C, and material flow rate 20-40 L / h.

8. The method for preparing a feed additive using feather hydrolysate according to claim 1, characterized in that: The parameters for inactivating the enzyme in step (6) are as follows: heating the enzymatically hydrolyzed material to 80-85° C. and maintaining the temperature for 10-15 minutes.

9. The method for preparing a feed additive using feather hydrolysate according to claim 1, characterized in that: In the step (6), the anti-caking agent is silicon dioxide and calcium phosphate in a mass ratio of 1:1, and the antioxidant is ethoxyquinoline or BHT.

10. A feed additive using feather hydrolysate, characterized in that: The feed additive is prepared by the preparation method of any one of claims 1 to 9.

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