Feed additive using feather hydrolysate and method for preparing the same

Abstract

The present application belongs to the field of biotechnology, and particularly relates to a feed additive using feather hydrolysate and a preparation method thereof, which comprises the following steps: (1) raw material pretreatment; (2) starch solidification; (3) fine grinding; (4) steaming treatment; (5) enzymolysis; (6) post-treatment: enzyme inactivation, solid-liquid separation, filtrate concentration, spray drying, and preparation of a composite hydrolysate, followed by addition of adjuvants to prepare the feed additive using feather hydrolysate. The present application realizes deep and uniform pre-destruction of feather keratin supermolecular structure in a low-cost and high-efficiency manner through construction of a physical brittle matrix, synergistic mechanical force and hydrothermal action, and creates an ideal reaction substrate for subsequent specific enzymolysis, so as to realize efficient conversion of feather protein and preparation of high-quality products under the premise of ensuring the integrity of target amino acids.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of biotechnology, and in particular, relates to a feed additive using feather hydrolysate and a preparation method thereof. BACKGROUND

[0002] Under the macro-background of the global development of livestock industry, the amount of waste feathers generated annually is extremely large, and its main chemical component is keratin with a protein content of more than 85%, which is a potential high-quality protein resource. Converting such waste biomass into high-value feed amino acids not only can effectively alleviate the supply pressure of feed protein raw materials, but also conforms to the industrial orientation of circular economy and sustainable development, thus having significant economic value and social significance.

[0003] The current mainstream technology for resource utilization of feathers mainly focuses on how to efficiently and mildly deconstruct the extremely stable keratin macromolecular structure. The keratin molecule has a large amount of compactness given by the β-sheet structure, and is further locked by a high-density disulfide bond and hydrogen bond cross-linking network, forming strong chemical inertness and physical toughness, which constitutes the core obstacle of resource utilization. In order to overcome this obstacle, various hydrolysis technologies have been developed by those skilled in the art. Among them, chemical hydrolysis, especially strong acid or strong base hydrolysis, as a classic process, its basic principle is to use the erosion of strong chemical reagents under high temperature and high pressure conditions to forcibly cut the peptide bond and disulfide bond, thereby realizing the depolymerization of keratin. This method has been applied in a certain historical period because of its fast processing speed and low requirement for raw material pretreatment. However, with the deepening of the cognition of product quality, nutritional value and environmental impact, the inherent defects of chemical hydrolysis in the principle level have become increasingly prominent. The severity of the reaction conditions not only attacks the peptide bond indiscriminately, but also causes serious damage to various nutritionally essential amino acids, for example, the destruction rate of tryptophan can be more than 95%, and the loss rate of sulfur-containing amino acids such as cystine and methionine is also as high as 30% to 50%. More seriously, non-specific chemical reactions can generate a series of harmful by-products, such as potentially toxic lysine and furan compounds, which significantly reduce the feed safety of the final product. In addition, the system after the reaction must be neutralized, and a large amount of inorganic salts introduced by this process make the ash content of the product as high as 20-35wt%, which not only affects the palatability of the feed, but also increases the metabolic burden of animals. If desalination is used afterwards, such as electrodialysis, the production cost will be significantly increased, which limits the feasibility of large-scale promotion.

[0004] To circumvent the above-mentioned drawbacks of chemical methods, research has shifted to physical auxiliary means and biological enzymatic methods. Physical methods such as microwave-assisted hydrolysis, whose mechanism lies in the use of microwave energy to selectively excite the high-frequency vibration of water molecules inside and around the feather, generating a local high-temperature and high-pressure effect to destroy the keratin structure. However, the fundamental limitation of such methods is the non-uniformity of energy transfer. In industrial production, the accumulation of large volumes of feather materials will produce a significant "cold center" effect, and the physical limitation of microwave penetration depth will result in a large temperature difference between the inside and outside of the material. The outside may have been over-hydrolyzed, while the inside may not have been hydrolyzed to 50% of the outside, ultimately resulting in uneven product hydrolysis, low yield of free amino acids, and a wide molecular weight distribution, making it difficult to meet the requirements of feed additives for component uniformity and high bioavailability.

[0005] On the contrary, enzymatic methods are considered the most promising green technology direction due to their mild reaction conditions, strong specificity, and pure products. This method uses specific keratinase to cleave peptide bonds under suitable mild conditions (such as neutral pH and 50-60°C). However, the industrialization process of this method has always been subject to a fundamental contradiction: the sharp opposition between the physical barrier effect of keratin and the accessibility of enzymatic reactions. The dense and hydrophobic supramolecular structure of feathers without effective pretreatment acts like a solid "fortress," making it difficult for keratinase molecules in an aqueous environment to penetrate and contact the internal effective action sites. Although conventional mechanical pulverization can increase the specific surface area, the excellent toughness of feathers makes the pulverization energy consumption huge, and it is difficult to obtain a small enough particle size, resulting in extremely slow enzymatic reaction rates. Even after a long time of hydrolysis, the protein dissolution rate is often less than 40%, and the economic benefit is poor. To solve this pretreatment bottleneck, the industry has tried advanced technologies such as plasma and nanomaterials, but these methods are mostly limited to surface modification and cannot achieve deep destruction of the feather bulk structure. While the super-micro pulverization technology can reduce the particle size to the micron level, it needs to use extreme conditions such as liquid nitrogen deep cooling to overcome the toughness of feathers, which makes the cost high and makes this path economically impractical.

[0006] In summary, existing feather hydrolysis technologies are generally trapped in a dilemma: pursuing efficient and thorough structural destruction inevitably leads to severe degradation of target amino acids and secondary pollution; while pursuing mild and conservative reaction conditions, it is difficult to effectively overcome the natural structural stubbornness of keratin, resulting in low reaction efficiency and high cost. This contradiction between "destruction" and "preservation" is a deep technical root that restricts the high-value utilization of feathers. Therefore, how to develop a new method that can achieve deep and uniform pretreatment of the dense structure of feathers at low cost and high efficiency, and 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 and technical problem that needs to be solved for technical personnel in the field. SUMMARY

[0007] The present application aims to overcome the inherent contradiction between destructive hydrolysis and mild hydrolysis in the prior art, i.e. the strong hydrolysis method leads to severe degradation of amino acids and secondary pollution, while the mild enzymatic hydrolysis method is inefficient due to the physical barrier effect of keratin. To achieve this purpose, the present application provides a feed additive using feather hydrolysate and a preparation method thereof, which realizes the deep and uniform pre-destruction of feather keratin supermolecular structure in a low-cost and high-efficiency manner by constructing a physically brittle matrix, synergizing mechanical force and hydrothermal action, to create an ideal reaction substrate for subsequent specific enzymatic hydrolysis, thereby realizing efficient conversion of feather protein and preparation of high-quality products under the premise of ensuring the integrity of target amino acids.

[0008] To achieve the above purpose, the technical scheme of the present application is:

[0009] A preparation method of a feed additive using feather hydrolysate, comprising the following steps:

[0010] Step (1) Raw material pretreatment: immediately freeze the washed feather, roll it, and coarsely crush it to 1-10 mm fragments;

[0011] Step (2) Starch solidification: mix the feather fragments with starch at a dry weight ratio of 1:1.2-1.8, add water to adjust the moisture content to 35-45%, steam gelatinize (90-100℃, 5-15min), and dry and solidify to a moisture content of 8-12%;

[0012] Step (3) Fine grinding: grind the solidified material to 40-100 mesh (0.15-0.42 mm);

[0013] Step (4) Cooking treatment: cook at 0.25-0.35 MPa, 120-130℃ for 10-20 min;

[0014] Step (5) Enzymatic hydrolysis: add amylase and keratinase to the cooked material, and hydrolyze at 50-60℃, pH 6.0-7.5 for 4-8 h;

[0015] Step (6) Post-treatment: inactivate the enzyme, separate the solid and liquid, concentrate the filtrate, spray dry to obtain a composite hydrolysate, and then add auxiliary materials to obtain a feed additive using feather hydrolysate.

[0016] The core innovation of the preparation method is to break down the bottleneck of feather processing through starch-mediated phase transition embrittlement. The feathers are immediately frozen after cleaning, and the rolling is due to the thick main stem of the feathers. By freezing, the toughness of the feathers is reduced by using water to freeze, and the main stem is broken after rolling, which helps the subsequent starch penetration and solidification and breaking. The continuous gel network formed by starch gelatinization realizes the precise balance between rigid skeleton and plastic residue when the controlled dehydration is to 8-12% moisture content: too low water content (<8%) will induce the reconstruction of keratin β-folded chain, resulting in the recurrence of feather fiber toughness; too high water content (>12%) will make the starch matrix residue viscoelastic, both of which will degrade the crushing efficiency. Within this critical interval, the three-dimensional brittle skeleton constructed by amylose retrogradation dominates, and the feather fibers are locked as discrete reinforced phases, and the material obtains the fracture characteristics of ceramic-like. When the crushing stress is applied, the crack preferentially propagates along the brittle starch phase and penetrates the feather-starch interface, so that the fiber is cut and dissociated rather than stretched and entangled. The micron-sized starch particles produced synchronously form a fluid lubricating layer on the device cavity wall, which not only blocks the fiber adhesion but also promotes the material flow, supplemented by the particle size homogenization effect brought by rigid restraint, completely avoiding the risk of screen clogging. This physical modification simultaneously enables the palatability of the final product - the reduction of sugar generated by starch enzymolysis activates the sweet receptors of animals, making the amino acid nutrient package and the foraging flavor body synergistically enhanced at the molecular level.

[0017] As preferred, the starch in step (2) is at least one of corn starch, cassava starch or wheat starch; the water vapor pressure during gelatinization is 0.1-0.2 MPa.

[0018] As preferred, it is characterized in that the amount of amylase added in step (5) is 5-15 U / g of dry starch, and the amount of keratinase added is 800-2000 U / g of dry feather protein; the amylase and keratinase are added synchronously; the amylase is a high-temperature-resistant α-amylase (optimum temperature 90-95°C), and the keratinase is a keratinase from Bacillus subtilis (optimum temperature 55-65°C).

[0019] As preferred, it is characterized in that the process of drying and solidification is:

[0020] a) Initial drying: 80°C hot air (air speed 2 m / s) drying to 18-20% moisture content;

[0021] b) Final drying: 45°C vacuum drying (-0.08 MPa) to 8-12% moisture content.

[0022] The drying process adopts a gradient dehydration strategy to avoid the problem of phase transition out of control caused by continuous hot air drying. The initial stage of 80°C hot air quickly removes free water, and the starch gel network is preliminarily shaped. At this time, the water content of 18-20% maintains sufficient plasticity to prevent stress cracking; the final stage switches to a 45°C vacuum environment to achieve key phase transition control. The low-pressure environment reduces the water evaporation enthalpy, prompting the bound water to migrate out at a temperature lower than the glass transition temperature of keratin (Tg≈50°C), which not only inhibits the toughness rebound caused by the reconstruction of β-folded chains, but also avoids the early consumption of reducing sugars caused by the Maillard reaction induced by high temperature. The inherent defect of continuous hot air drying is that a single high-temperature field causes the surface of the material to harden and form a vapor pressure barrier, the internal water vaporization is blocked, and the expansion stress is generated, which causes the feather-starch interface to peel off; at the same time, the hot air convection promotes the orientation of feather fibers along the airflow direction, inducing anisotropic shrinkage, forming a micro-crack network in the starch matrix. These pre-existing defects will become stress concentration sources during powdering, leading to uncontrolled powdering rate and discrete particle size distribution, significantly increasing the difficulty of subsequent enzymatic hydrolysis liquid-solid separation. The decoupling control of temperature-pressure-mass transfer rate by staged drying ensures that the water gradient is always lower than the critical fracture toughness, ensuring that the material enters the crushing section in an intrinsic brittle state, and realizing the fundamental change of the fracture mode from fiber pulling to overall brittle fracture.

[0023] As preferred, the step (6) solid-liquid separation adopts centrifugal separation, 3000-5000 rpm, 10-20 min, and the filter residue has a water content of ≤40 wt%, which is used as an organic fertilizer raw material.

[0024] As preferred, the step (6) concentration adopts reverse osmosis membrane concentration, and the operation pressure is 1.5-3.0 MPa, so as to increase the concentration to 20-30 wt%.

[0025] As preferred, the step (6) spray drying parameters are: inlet air temperature 160-180°C, outlet air temperature 70-85°C, and material flow rate 20-40 L / h.

[0026] As preferred, the step (6) enzyme inactivation parameters are: the enzyme-hydrolyzed material is heated to 80-85°C and maintained for 10-15 min.

[0027] As preferred, the prepared feed additive using feather hydrolysate comprises, by weight, 60-85 parts of a complex hydrolysate, 0.5-2 parts of an anti-caking agent, and 0.1-0.5 parts of an antioxidant.

[0028] The anti-caking agent is selected from at least one of silicon dioxide and calcium phosphate; and the antioxidant is ethoxyquin or 2,6-di-tert-butyl-p-cresol (BHT).

[0029] The scheme also discloses a feed additive using feather hydrolysate prepared by the above method for preparing a feed additive using feather hydrolysate.

[0030] Compared with the prior art, the advantages of the scheme are:

[0031] The scheme overturns the traditional feather processing mode through a three-stage linkage of starch phase change embrittlement-steam directional bond breaking-bi-enzyme synergistic conversion. The rigid network formed by starch gelatinization converts the feather fibers into "brittle composite materials" at a critical moisture content of 8-12%, breaking the energy consumption dead end of superfine crushing; steam promotes the breaking of disulfide bonds, avoiding the devastating damage of strong acid and strong base to amino acids; in the bi-enzyme step-by-step hydrolysis strategy, amylase removes the coating barrier first, and keratinase digests the peptide segments. The end product integrates sulfur-containing amino acids from feathers and starch-based reducing sugars, which can improve palatability, and the waste residue can be used to make organic fertilizer, without waste materials. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0033] General embodiment:

[0034] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0035] Step (1) Raw material pretreatment: immediately freeze the washed feathers at -10°C, roll and crush the feather stems, and coarsely crush them into 1-10 mm fragments;

[0036] Step (2) Starch solidification: mix the feather fragments with starch at a dry weight ratio of 1:1.2-1.8, add water to adjust the moisture content to 35-45%, and steam gelatinize at 90-100°C for 5-15 min, then dry and solidify 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;

[0037] The process of drying and solidification is:

[0038] a) Initial drying: dry at 80°C with hot air (air speed 2 m / s) to a moisture content of 18-20%;

[0039] b) Final drying: vacuum drying (0.08 MPa) at 45°C to a moisture content of 8-12%;

[0040] Step (3) Fine crushing: crush the solidified material to 40-100 mesh (0.15-0.42 mm);

[0041] Step (4) Cooking treatment: cooking at 0.25-0.35 MPa, 120-130℃ for 10-20 min;

[0042] Step (5) Enzymatic hydrolysis: adding amylase and keratinase to the cooked material, and hydrolyzing at 50-60℃, pH 6.0-7.5 for 4-8 h; the amylase is added at 5-15 U / g dry weight of starch, and the keratinase is added at 800-2000 U / g dry weight of feather protein; the amylase and the keratinase are added synchronously; the amylase is a high-temperature-resistant α-amylase, and the keratinase is a keratinase from Bacillus subtilis;

[0043] Step (6) Post-treatment: inactivating the enzymes, heating to 80-85℃ for 10-15 min, separating at 3000-5000 rpm for 10-20 min, concentrating the filtrate by reverse osmosis membrane at an operating pressure of 1.5-3.0 MPa, increasing the concentration to 20-30 wt%, and spray drying at an inlet air temperature of 160-180℃ and an outlet air temperature of 70-85℃ and a material flow rate of 20-40 L / h to obtain a composite hydrolysate, and then adding auxiliary materials to obtain a feed additive using feather hydrolysate;

[0044] The feed additive using feather hydrolysate is prepared from 60-85 parts by weight of the composite hydrolysate, 1 part of silicon dioxide, 1 part of calcium phosphate, 0.1-0.5 parts of ethoxyquin or BHT.

[0045] Example 1:

[0046] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0047] Step (1) Raw material pretreatment: immediately freezing the washed feather at -10℃, and crushing the feather stem by rolling to 5 mm fragments;

[0048] Step (2) Starch solidification: mixing the feather fragments with corn starch at a dry weight ratio of 1:1.5, adding water to a moisture content of 40%, and gelatinizing at 95℃ for 10 min under a water vapor pressure of 0.15 MPa; the drying and solidification process includes: a) initial drying at 80℃ with a hot air speed of 2 m / s until the moisture content is 19%; b) final drying at 45℃ under a vacuum degree of -0.08 MPa until the moisture content is 10%;

[0049] Step (3) Fine crushing: crushing the solidified material to 100 mesh;

[0050] Step (4) Cooking treatment: cooking at 0.3 MPa, 125℃ for 15 min;

[0051] Step (5) Enzymatic hydrolysis: add thermostable alpha-amylase and Bacillus subtilis keratinase into the cooked material, the amylase is added at 10 U / g dry weight of starch, the keratinase is added at 1500 U / g dry weight of feather protein, and hydrolysis is carried out at 55°C and pH 6.8 for 6 hours;

[0052] Step (6) Post-treatment: inactivate the enzyme and raise the temperature to 82°C for 12 minutes, separate the solid and liquid by centrifugation at 4000 rpm for 15 minutes, concentrate the filtrate by reverse osmosis membrane at an operating pressure of 2.0 MPa to 25 wt%, and spray dry at an inlet temperature of 170°C, an outlet temperature of 75°C, and a material flow rate of 30 L / h to obtain a composite hydrolysate; take 85 parts by weight of the composite hydrolysate, add 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin to obtain a feed additive using feather hydrolysate.

[0053] Example 2:

[0054] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0055] Step (1) Raw material pretreatment: immediately freeze the washed feather at -10°C, roll and crush the feather stem, and coarsely crush to 3 mm fragments;

[0056] Step (2) Starch solidification: mix the feather fragments with cassava starch at a dry weight ratio of 1:1.2, add water to adjust the moisture content to 35%, and perform steam gelatinization at 90°C for 15 minutes, with a steam pressure of 0.1 MPa; the drying and solidification process is as follows: a) initial drying: dry at 80°C with a hot air speed of 2 m / s to a moisture content of 18%; b) final drying: vacuum drying at 45°C to a moisture content of 8% at a vacuum degree of -0.08 MPa;

[0057] Step (3) Fine grinding: grind the solidified material to 40 mesh;

[0058] Step (4) Cooking treatment: cook at 0.25 MPa and 120°C for 20 minutes;

[0059] Step (5) Enzymatic hydrolysis: add thermostable alpha-amylase and Bacillus subtilis keratinase into the cooked material, the amylase is added at 10 U / g dry weight of starch, the keratinase is added at 1500 U / g dry weight of feather protein, and hydrolysis is carried out at 55°C and pH 6.8 for 6 hours;

[0060] Step (6) post-treatment: enzyme inactivation, temperature rise to 80℃ for 15 min, solid-liquid separation by centrifugation at 3000 rpm for 20 min, concentration of the filtrate by reverse osmosis membrane at an operating pressure of 1.5 MPa to 20 wt%, spray drying at an inlet temperature of 160℃, an outlet temperature of 70℃, and a material flow rate of 20 L / h, to obtain a composite hydrolysate; taking 60 parts by weight of the composite hydrolysate, adding 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.1 part of BHT, to obtain a feed additive using feather hydrolysate.

[0061] Example 3:

[0062] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0063] Step (1) raw material pretreatment: immediately freeze the washed feather at -10℃, roll and crush the feather stem, and coarsely crush to 8 mm fragments;

[0064] Step (2) starch solidification: mix the feather fragments with wheat starch at a dry weight ratio of 1:1.8, add water to adjust the moisture content to 45%, and perform steam gelatinization at 100℃ for 5 min, with a steam pressure of 0.2 MPa; the drying and solidification process is as follows: a) initial drying: dry at 80℃ with a hot air speed of 2 m / s to a moisture content of 20%; b) final drying: vacuum drying at 45℃ to a moisture content of 12% at a vacuum degree of -0.08 MPa;

[0065] Step (3) fine grinding: grind the solidified material to 100 mesh;

[0066] Step (4) cooking treatment: cook at 0.35 MPa and 130℃ for 10 min;

[0067] Step (5) enzymatic hydrolysis: add thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, the amylase is added at an amount of 15 U / g of dry starch, and the keratinase is added at an amount of 2000 U / g of dry feather protein, and hydrolyze at 60℃ and pH 7.5 for 4 h;

[0068] Step (6) post-treatment: enzyme inactivation, temperature rise to 85℃ for 10 min, solid-liquid separation by centrifugation at 5000 rpm for 10 min, concentration of the filtrate by reverse osmosis membrane at an operating pressure of 3.0 MPa to 30 wt%, spray drying at an inlet temperature of 180℃, an outlet temperature of 85℃, and a material flow rate of 40 L / h, to obtain a composite hydrolysate; taking 85 parts by weight of the composite hydrolysate, adding 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.5 parts of ethoxyquin, to obtain a feed additive using feather hydrolysate.

[0069] Example 4:

[0070] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0071] Step (1) Raw material pretreatment: immediately freeze the washed feather at -10℃, roll and break the feather stem, and coarsely crush it into 1mm fragments;

[0072] Step (2) Starch solidification: mix the feather fragments with corn starch at a dry weight ratio of 1:1.3, add water to adjust the moisture content to 37%, and steam gelatinize at 92℃ for 12min, with a water vapor pressure of 0.12MPa during gelatinization; the drying and solidification process is as follows: a) initial drying: dry at 80℃ with a hot air speed of 2m / s until the moisture content is 18.5%; b) final drying: vacuum drying at 45℃ with a vacuum degree of -0.08MPa until the moisture content is 9%;

[0073] Step (3) Fine crushing: crush the solidified material to 50 mesh;

[0074] Step (4) Cooking treatment: cook at 0.28MPa and 122℃ for 18min;

[0075] Step (5) Enzymatic hydrolysis: add thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with an amylase addition amount of 8U / g of starch dry weight and a keratinase addition amount of 1000U / g of feather protein dry weight, and hydrolyze at 52℃ and pH6.3 for 7h;

[0076] Step (6) Post-treatment: heat to 81℃ for 14min to inactivate the enzymes, and then centrifuge at 3500rpm for 18min to separate the solid and liquid; concentrate the filtrate by reverse osmosis membrane with an operating pressure of 2.2MPa to 22wt%, and then spray dry with an inlet air temperature of 165℃, an outlet air temperature of 72℃, and a material flow rate of 25L / h to obtain a composite hydrolysate; take 70 parts by weight of the composite hydrolysate, add 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.2 parts of BHT to obtain a feed additive using feather hydrolysate.

[0077] Example 5:

[0078] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0079] Step (1) Raw material pretreatment: immediately freeze the washed feather at -10℃, roll and break the feather stem, and coarsely crush it into 10mm fragments;

[0080] Step (2) Starch solidification: mix the feather fragments with cassava starch at a dry weight ratio of 1:1.6, add water to adjust the moisture content to 42%, and steam gelatinize at 98℃ for 8min, with a water vapor pressure of 0.18MPa during gelatinization; the drying and solidification process is as follows: a) initial drying: dry at 80℃ with a hot air speed of 2m / s until the moisture content is 19.5%; b) final drying: vacuum drying at 45℃ with a vacuum degree of -0.08MPa until the moisture content is 11%;

[0081] Step (3) Fine grinding: grinding the solidified material to 80 mesh;

[0082] Step (4) Cooking treatment: cooking at 0.32 MPa, 128°C for 12 min;

[0083] Step (5) Enzymatic hydrolysis: adding thermostable alpha-amylase and Bacillus subtilis keratinase to the cooked material, the amylase being added at 12 U / g of dry starch, and the keratinase being added at 1800 U / g of dry feather protein, and hydrolyzing at 58°C, pH 7.2 for 5 h;

[0084] Step (6) Post-treatment: inactivating the enzyme and raising the temperature to 83°C for 11 min, solid-liquid separation by centrifugation at 4500 rpm for 12 min, concentration of the filtrate by reverse osmosis membrane at an operating pressure of 2.5 MPa to 28 wt%, spray drying at an inlet temperature of 175°C, an outlet temperature of 80°C, and a material flow rate of 35 L / h, to obtain a composite hydrolysate; taking 75 parts by weight of the composite hydrolysate, adding 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.4 parts of ethoxyquin, to obtain a feed additive using feather hydrolysate.

[0085] Comparative Example 1:

[0086] The difference from Example 1 is that no starch is used for solidification:

[0087] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0088] Step (1) Raw material pretreatment: freezing the feather immediately after washing at -10°C, and crushing the feather stem by rolling to 5 mm fragments;

[0089] Step (2) Cooking treatment: cooking at 0.3 MPa, 125°C for 15 min;

[0090] Step (3) Enzymatic hydrolysis: adding Bacillus subtilis keratinase to the cooked material, the keratinase being added at 1500 U / g of dry feather protein, and hydrolyzing at 55°C, pH 6.8 for 6 h;

[0091] Step (4) Post-treatment: inactivating the enzyme and raising the temperature to 82°C for 12 min, solid-liquid separation by centrifugation at 4000 rpm for 15 min, concentration of the filtrate by reverse osmosis membrane at an operating pressure of 2.0 MPa to 25 wt%, spray drying at an inlet temperature of 170°C, an outlet temperature of 75°C, and a material flow rate of 30 L / h, to obtain feather hydrolyzed amino acids; taking 85 parts by weight of the composite hydrolysate, adding 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin, to obtain a feed additive using feather hydrolysate.

[0092] Comparative Example 2:

[0093] The difference from Example 1 is that the pure hot air curing is used:

[0094] A preparation method of a feed additive using feather hydrolysate, comprising the following steps:

[0095] Step (1) raw material pretreatment: immediately freeze the washed feather at -10°C, roll and crush the feather stem, and coarsely crush it into 5mm fragments;

[0096] Step (2) starch curing: mix the feather fragments with corn starch at a dry weight ratio of 1:1.5, add water to adjust the moisture content to 40%, and gelatinize at 95°C for 10min under a water vapor pressure of 0.15MPa; the drying and curing process is as follows: a) initial drying: dry at 80°C with a hot air speed of 2m / s until the moisture content is 10%;

[0097] Step (3) fine crushing: crush the cured material to 100 mesh;

[0098] Step (4) cooking treatment: cook at 0.3MPa and 125°C for 15min;

[0099] Step (5) enzymatic hydrolysis: add thermostable alpha-amylase and Bacillus subtilis-derived keratinase to the cooked material, the amylase is added at an amount of 10U / g of starch dry weight, and the keratinase is added at an amount of 1500U / g of feather protein dry weight, and hydrolyze at 55°C and pH 6.8 for 6h;

[0100] Step (6) post-treatment: heat to 82°C for 12min to inactivate the enzyme, centrifuge at 4000rpm for 15min for solid-liquid separation, concentrate the filtrate to 25wt% by reverse osmosis membrane concentration at an operating pressure of 2.0MPa, and spray dry at an inlet air temperature of 170°C, an outlet air temperature of 75°C, and a material flow rate of 30L / h to obtain a composite hydrolysate; take 85 parts by weight of the composite hydrolysate, add 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin to obtain a feed additive using feather hydrolysate.

[0101] Comparative Example 3:

[0102] The difference from Example 1 is that the feather fragments are mixed with corn starch at a dry weight ratio of 1:2, and water is added to adjust the moisture content to 30%:

[0103] A preparation method of a feed additive using feather hydrolysate, comprising the following steps:

[0104] Step (1) raw material pretreatment: immediately freeze the washed feather at -10°C, roll and crush the feather stem, and coarsely crush it into 5mm fragments;

[0105] Step (2) Starch solidification: mix the feather fragments with corn starch at a dry weight ratio of 1:2, add water to adjust the moisture content to 30%, and steam at 95°C for 10 min with a water vapor pressure of 0.15 MPa; the drying and solidification process is as follows: a) initial drying: dry at 80°C with a hot air speed of 2 m / s until the moisture content is 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa until the moisture content is 10%;

[0106] Step (3) Fine grinding: grind the solidified material to 100 mesh;

[0107] Step (4) Cooking treatment: cook at 0.3 MPa and 125°C for 15 min;

[0108] Step (5) Enzymatic hydrolysis: add thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, the amylase is added at a dosage of 10 U / g of dry starch, and the keratinase is added at a dosage of 1500 U / g of dry feather protein, and hydrolyze at 55°C and pH 6.8 for 6 h;

[0109] Step (6) Post-treatment: heat to 82°C for 12 min to inactivate the enzyme, and then centrifuge at 4000 rpm for 15 min to separate the solid and liquid, the filtrate is concentrated by reverse osmosis membrane at an operating pressure of 2.0 MPa to 25 wt%, and then spray dried at an inlet temperature of 170°C and an outlet temperature of 75°C with a material flow rate of 30 L / h to obtain a composite hydrolysate; take 85 parts by weight of the composite hydrolysate, add 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquinoline to obtain a feed additive using feather hydrolysate.

[0110] Comparative Example 4:

[0111] The difference from Example 1 is that after drying and solidification, the moisture content is too high:

[0112] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0113] Step (1) Raw material pretreatment: immediately freeze the washed feathers at -10°C, roll and crush the feather stems, and coarsely crush to 5 mm fragments;

[0114] Step (2) Starch solidification: mix the feather fragments with corn starch at a dry weight ratio of 1:1.5, add water to adjust the moisture content to 40%, and steam at 95°C for 10 min with a water vapor pressure of 0.15 MPa; the drying and solidification process is as follows: a) initial drying: dry at 80°C with a hot air speed of 2 m / s until the moisture content is 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa until the moisture content is 15%;

[0115] Step (3) Fine grinding: grind the solidified material to 100 mesh;

[0116] Step (4) Cooking treatment: cooking at 0.3 MPa, 125℃ for 15 min;

[0117] Step (5) Enzymatic hydrolysis: adding thermostable α-amylase and Bacillus subtilis keratinase into the cooked material, the amount of amylase is 10 U / g dry weight of starch, the amount of keratinase is 1500 U / g dry weight of feather protein, hydrolyzing at 55℃, pH 6.8 for 6 h;

[0118] Step (6) Post-treatment: inactivating the enzyme and heating to 82℃ for 12 min, separating the solid and liquid by centrifugation at 4000 rpm for 15 min, concentrating the filtrate by reverse osmosis membrane at an operating pressure of 2.0 MPa to 25 wt%, and spray drying at an inlet temperature of 170℃, an outlet temperature of 75℃, and a material flow rate of 30 L / h to obtain a composite hydrolysate; taking 85 parts by weight of the composite hydrolysate, adding 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin to obtain a feed additive using feather hydrolysate.

[0119] Comparative Example 5:

[0120] The difference from Example 1 is that the water content is too low after drying and solidification:

[0121] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0122] Step (1) Raw material pretreatment: freezing the washed feather immediately at -10℃, crushing the feather stem by rolling, and coarsely crushing to 5 mm fragments;

[0123] Step (2) Starch solidification: mixing the feather fragments with corn starch at a dry weight ratio of 1:1.5, adding water to adjust the water content to 40%, and gelatinizing at 95℃ for 10 min under a water vapor pressure of 0.15 MPa; the drying and solidification process is as follows: a) initial drying: drying at 80℃ with a hot air speed of 2 m / s to a water content of 19%; b) final drying: vacuum drying at 45℃ to a water content of 5% at a vacuum degree of -0.08 MPa;

[0124] Step (3) Fine crushing: crushing the solidified material to 100 mesh;

[0125] Step (4) Cooking treatment: cooking at 0.3 MPa, 125℃ for 15 min;

[0126] Step (5) Enzymatic hydrolysis: adding thermostable α-amylase and Bacillus subtilis keratinase into the cooked material, the amount of amylase is 10 U / g dry weight of starch, the amount of keratinase is 1500 U / g dry weight of feather protein, hydrolyzing at 55℃, pH 6.8 for 6 h;

[0127] Step (6) post-treatment: enzyme inactivation, temperature rise to 82°C for 12 min, solid-liquid separation by centrifugation at 4000 rpm for 15 min, concentration of the filtrate by reverse osmosis membrane at an operating pressure of 2.0 MPa to 25 wt%, spray drying at an inlet temperature of 170°C, an outlet temperature of 75°C, and a material flow rate of 30 L / h, to obtain a composite hydrolysate; taking 85 parts by weight of the composite hydrolysate, adding 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin, to obtain a feed additive using feather hydrolysate.

[0128] Comparative Example 6:

[0129] The difference from Example 1 is that cooling solidification is used, and the moisture content is 22%:

[0130] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0131] Step (1) raw material pretreatment: immediately freeze the washed feathers at -10°C, roll and crush the feather stems, and coarsely crush to 5 mm fragments;

[0132] Step (2) starch solidification: mix the feather fragments with corn starch at a dry weight ratio of 1:1.5, add water to adjust the moisture content to 40%, and gelatinize at 95°C for 10 min under a water vapor pressure of 0.15 MPa; after cooling and solidification, the moisture content is 22%;

[0133] Step (3) fine grinding: grind the solidified material to 100 mesh;

[0134] Step (4) cooking treatment: cook at 0.3 MPa and 125°C for 15 min;

[0135] Step (5) enzymatic hydrolysis: add thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, the amylase is added at an amount of 10 U / g of starch dry weight, and the keratinase is added at an amount of 1500 U / g of feather protein dry weight, and hydrolyze at 55°C and pH 6.8 for 6 h;

[0136] Step (6) post-treatment: enzyme inactivation, temperature rise to 82°C for 12 min, solid-liquid separation by centrifugation at 4000 rpm for 15 min, concentration of the filtrate by reverse osmosis membrane at an operating pressure of 2.0 MPa to 25 wt%, spray drying at an inlet temperature of 170°C, an outlet temperature of 75°C, and a material flow rate of 30 L / h, to obtain a composite hydrolysate; taking 85 parts by weight of the composite hydrolysate, adding 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin, to obtain a feed additive using feather hydrolysate.

[0137] Comparative Example 7:

[0138] The difference from Example 1 is that the solidified material is ground to 20 mesh:

[0139] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0140] Step (1) Raw material pretreatment: immediately freeze the washed feather at -10°C, roll and crush the feather stem, and coarsely crush it into 5 mm fragments;

[0141] Step (2) Starch solidification: mix the feather fragments with corn starch at a dry weight ratio of 1:1.5, add water to adjust the moisture content to 40%, and perform steam gelatinization at 95°C for 10 min, with a water vapor pressure of 0.15 MPa during gelatinization; the drying and solidification process is as follows: a) initial drying: dry at 80°C with a hot air speed of 2 m / s until the moisture content is 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa until the moisture content is 10%;

[0142] Step (3) Fine crushing: crush the solidified material to 20 mesh;

[0143] Step (4) Cooking treatment: cook at 0.3 MPa and 125°C for 15 min;

[0144] Step (5) Enzymatic hydrolysis: add thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, with an amylase addition amount of 10 U / g of starch dry weight and a keratinase addition amount of 1500 U / g of feather protein dry weight, and hydrolyze at 55°C and pH 6.8 for 6 h;

[0145] Step (6) Post-treatment: heat to 82°C for 12 min to inactivate the enzyme, perform solid-liquid separation by centrifugation at 4000 rpm for 15 min, concentrate the filtrate by reverse osmosis membrane with an operating pressure of 2.0 MPa to 25 wt%, and perform spray drying with 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 hydrolysate; take 85 parts by weight of the composite hydrolysate, add 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin to obtain a feed additive using feather hydrolysate.

[0146] Comparative Example 8:

[0147] The difference from Example 1 is that there is no step (4) cooking treatment:

[0148] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0149] Step (1) Raw material pretreatment: immediately freeze the washed feather at -10°C, roll and crush the feather stem, and coarsely crush it into 5 mm fragments;

[0150] Step (2) Starch solidification: mix the feather fragments with corn starch at a dry weight ratio of 1:1.5, add water to adjust the moisture content to 40%, and steam at 95°C for 10 min with a steam pressure of 0.15 MPa; the drying and solidification process is as follows: a) initial drying: dry at 80°C with a hot air speed of 2 m / s until the moisture content is 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa until the moisture content is 10%;

[0151] Step (3) Fine grinding: grind the solidified material to 100 mesh;

[0152] Step (4) Enzymatic hydrolysis: add thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, the amylase is added at a dosage of 10 U / g of dry starch, and the keratinase is added at a dosage of 1500 U / g of dry feather protein, and hydrolysis is carried out at 55°C and pH 6.8 for 6 hours;

[0153] Step (5) Post-treatment: heat to 82°C for 12 min to inactivate the enzyme, and then centrifuge at 4000 rpm for 15 min to separate the solid and liquid, the filtrate is concentrated by reverse osmosis membrane at an operating pressure of 2.0 MPa to a concentration of 25 wt%, and then spray dried at an inlet temperature of 170°C and an outlet temperature of 75°C at a material flow rate of 30 L / h to obtain a composite hydrolysate; take 85 parts by weight of the composite hydrolysate, add 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin to obtain a feed additive using feather hydrolysate.

[0154] Comparative Example 9:

[0155] The difference from Example 1 is that there is no enzyme inactivation treatment:

[0156] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0157] Step (1) Raw material pretreatment: immediately freeze the washed feather at -10°C, roll and crush the feather stem, and coarsely crush to 5 mm fragments;

[0158] Step (2) Starch solidification: mix the feather fragments with corn starch at a dry weight ratio of 1:1.5, add water to adjust the moisture content to 40%, and steam at 95°C for 10 min with a steam pressure of 0.15 MPa; the drying and solidification process is as follows: a) initial drying: dry at 80°C with a hot air speed of 2 m / s until the moisture content is 19%; b) final drying: vacuum drying at 45°C with a vacuum degree of -0.08 MPa until the moisture content is 10%;

[0159] Step (3) Fine grinding: grind the solidified material to 100 mesh;

[0160] Step (4) Cooking treatment: cook at 0.3 MPa and 125°C for 15 min;

[0161] Step (5) Enzymatic hydrolysis: add thermostable alpha-amylase and Bacillus subtilis keratinase into the cooked material, the amylase is added at 10 U / g dry weight of starch, and the keratinase is added at 1500 U / g dry weight of feather protein, and hydrolysis is carried out at 55°C and pH 6.8 for 6 hours;

[0162] Step (6) Post-treatment: solid-liquid separation by centrifugation at 4000 rpm for 15 minutes, concentration of the filtrate by reverse osmosis membrane at an operating pressure of 2.0 MPa to 25 wt%, spray drying 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 hydrolysate; taking 85 parts by weight of the composite hydrolysate, adding 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin to obtain a feed additive using feather hydrolysate.

[0163] Comparative Example 10:

[0164] The difference from Example 1 is that the concentration after concentration in step (6) is 35%:

[0165] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0166] Step (1) Raw material pretreatment: immediately freeze the washed feather at -10°C, roll and crush the feather stem, and coarsely crush it to 5 mm fragments;

[0167] Step (2) Starch solidification: mix the feather fragments with corn starch at a dry weight ratio of 1:1.5, add water to a moisture content of 40%, and gelatinize at 95°C for 10 minutes under a water vapor pressure of 0.15 MPa; the drying and solidification process is as follows: a) initial drying: dry at 80°C with a hot air speed of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45°C to a moisture content of 10% at a vacuum degree of -0.08 MPa;

[0168] Step (3) Fine grinding: grind the solidified material to 100 mesh;

[0169] Step (4) Cooking treatment: cook at 0.3 MPa and 125°C for 15 minutes;

[0170] Step (5) Enzymatic hydrolysis: add thermostable alpha-amylase and Bacillus subtilis keratinase into the cooked material, the amylase is added at 10 U / g dry weight of starch, and the keratinase is added at 1500 U / g dry weight of feather protein, and hydrolysis is carried out at 55°C and pH 6.8 for 6 hours;

[0171] Step (6) post-treatment: enzyme inactivation, temperature raised to 82℃ for 12 min, solid-liquid separation by centrifugation at 4000 rpm for 15 min, the filtrate concentrated by reverse osmosis membrane at an operating pressure of 2.0 MPa to 35 wt%, spray drying with an inlet temperature of 170℃, an outlet temperature of 75℃, and a material flow rate of 30 L / h, to obtain the composite hydrolysate; taking 85 parts by weight of the composite hydrolysate, adding 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin, to obtain the feed additive using feather hydrolysate.

[0172] Comparative Example 11:

[0173] The difference from Example 1 is that the pulverization is to a particle size of 120 mesh:

[0174] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0175] Step (1) raw material pretreatment: immediately freeze the feathers at -10℃ after washing, roll and crush the feather stems, and coarsely crush to 5 mm fragments;

[0176] Step (2) starch solidification: mix the feather fragments with corn starch at a dry weight ratio of 1:1.5, add water to a moisture content of 40%, and gelatinize at 95℃ for 10 min under water vapor pressure of 0.15 MPa; the drying and solidification process is as follows: a) initial drying: dry at 80℃ with hot air at a speed of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45℃ to a moisture content of 10% at a vacuum degree of -0.08 MPa;

[0177] Step (3) fine pulverization: pulverize the solidified material to 120 mesh;

[0178] Step (4) cooking treatment: cook at 0.3 MPa and 125℃ for 15 min;

[0179] Step (5) enzymatic hydrolysis: add thermostable α-amylase and Bacillus subtilis-derived keratinase to the cooked material, the amylase is added at an amount of 10 U / g of dry starch, and the keratinase is added at an amount of 1500 U / g of dry feather protein, and hydrolyze at 55℃ and pH 6.8 for 6 h;

[0180] Step (6) post-treatment: enzyme inactivation, temperature raised to 82℃ for 12 min, solid-liquid separation by centrifugation at 4000 rpm for 15 min, the filtrate concentrated by reverse osmosis membrane at an operating pressure of 2.0 MPa to 25 wt%, spray drying with an inlet temperature of 170℃, an outlet temperature of 75℃, and a material flow rate of 30 L / h, to obtain the composite hydrolysate; taking 85 parts by weight of the composite hydrolysate, adding 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin, to obtain the feed additive using feather hydrolysate.

[0181] Comparative Example 12:

[0182] The difference from Example 1 is that no freezing and rolling are performed:

[0183] A method for preparing a feed additive using feather hydrolysate, comprising the following steps:

[0184] Step (1) Raw material pretreatment: after washing, the feather is coarsely broken into 5 mm pieces;

[0185] Step (2) Starch solidification: the feather pieces are mixed with corn starch at a dry weight ratio of 1:1.5, water is added to a moisture content of 40%, and 95℃ water steam gelatinization is performed for 10 min, the water vapor pressure during gelatinization is 0.15 MPa; the drying and solidification process is as follows: a) initial drying: 80℃ hot air at a speed of 2 m / s to a moisture content of 19%; b) final drying: vacuum drying at 45℃ to a moisture content of 10% at a vacuum degree of -0.08 MPa;

[0186] Step (3) Fine grinding: the solidified material is ground to 120 mesh;

[0187] Step (4) Cooking treatment: cooking at 0.3 MPa and 125℃ for 15 min;

[0188] Step (5) Enzymatic hydrolysis: high-temperature-resistant α-amylase and Bacillus subtilis-derived keratinase are added to the cooked material, the amylase is added at an amount of 10 U / g of starch dry weight, the keratinase is added at an amount of 1500 U / g of feather protein dry weight, and hydrolysis is performed at 55℃ and pH 6.8 for 6 h;

[0189] Step (6) Post-treatment: enzyme inactivation by heating to 82℃ for 12 min, solid-liquid separation by centrifugation at 4000 rpm for 15 min, concentration of the filtrate by reverse osmosis membrane at an operating pressure of 2.0 MPa to 25 wt%, spray drying at an inlet temperature of 170℃, an outlet temperature of 75℃, and a material flow rate of 30 L / h to obtain a composite hydrolysate; taking 85 parts by weight of the composite hydrolysate, adding 1 part of silicon dioxide and 1 part of calcium phosphate, and 0.3 parts of ethoxyquin to obtain a feed additive using feather hydrolysate.

[0190] Detection method:

[0191] Raw material utilization rate: 100%-dry weight of filter residue / (dry weight of feather+dry weight of starch)×100%; since no impurities are added in this scheme, the starch hydrolysate is sugar, which is also one of the conventional feed additives, so the raw material utilization rate is the simplest yield calculation.

[0192] Total amount of amino acids: 10 g of the feed additive prepared using feather hydrolysate was dissolved in 1000 g of water, and the total amount of amino acids was determined by automatic amino acid analyzer. The total amount of amino acids of the commercially available feed additive using feather hydrolysate was compared. The experimental process and results are shown in Table 1.

[0193] Table 1 Experimental process and results of examples and comparative examples

[0194]

[0195] The preparation process of the feed additive using feather hydrolysate constructed in the embodiment of the application realizes a technical breakthrough while exhibiting significant simplicity and industrial adaptation advantages. The innovation core is to realize efficient conversion through process logic reconstruction rather than equipment replacement based on a conventional equipment chain. The raw material pretreatment uses general refrigeration roller pressing and mixing equipment, the starch solidification link directly uses the conditioner popular in the feed industry to complete gelatinization, and the gradient drying process (80℃ hot air + 45℃ vacuum) is fully compatible with the drying tower parameters of the existing feed production line; the subsequent cooking, enzymatic hydrolysis, centrifugation, and spray drying unit operations are seamlessly connected to the standard production line of industrial feed additives, without the need for additional special equipment or pipeline modification. This design makes it possible to adjust the process parameters (such as controlling the starch moisture content at 8-12%, and the cooking pressure at 0.25-0.35 MPa) in the existing feed factory to quickly land the technology upgrade, greatly reducing the industrialization threshold. Especially crucial is that this process replaces complex pretreatment methods such as ultrafine grinding or plasma treatment with a low-cost solution through starch-mediated phase change embrittlement effect, improving the efficiency of traditional enzymatic hydrolysis while ensuring 92.5% raw material utilization and 48.2 g / 100 g amino acid yield, and the whole process is free of strong acid / alkali neutralization steps, and the waste residue can be used for inorganic fertilizer production.

Claims

1. A method for preparing a feed additive using feather hydrolysate, characterized by, It comprises the following steps: Step (1) raw material pretreatment: immediately freeze the washed feather, roll, and roughly crush to 1-10 mm fragments; Step (2) starch solidification: mix the feather fragments with starch at a dry weight ratio of 1:1.2-1.8, add water to a moisture content of 35-45%, steam gelatinize, and dry and solidify to a moisture content of 8-12%; Step (3) fine crushing: crush the solidified material to 40-100 mesh; Step (4) cooking treatment: cook at 0.25-0.35 MPa and 120-130℃ for 10-20 min; Step (5) enzymatic hydrolysis: add amylase and keratinase to the cooked material, hydrolyze at 50-60℃ and pH 6.0-7.5 for 4-8 h; Step (6) post-treatment: inactivate the enzyme, separate the solid and liquid, concentrate the filtrate, and spray dry to obtain a composite hydrolysate; prepare a feed additive using feather hydrolysate by mixing 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, In the process of drying and solidifying: a) initial drying: 80℃ hot air drying to a moisture content of 18-20%; b) final drying: 45℃ vacuum drying to a moisture content of 8-12%.

2. The method of claim 1, wherein the feed additive is prepared by the steps of: a) mixing the feather hydrolysate with a feed additive carrier; b) drying the mixture; and c) milling the dried mixture to a desired particle size. The starch in step (2) is at least one of corn starch, cassava starch, or wheat starch; and the steam pressure during gelatinization is 0.1-0.2 MPa.

3. The method of claim 1, wherein the feed additive is prepared by the steps of: a) mixing the feather hydrolysate with a feed additive carrier; b) drying the mixture; and c) milling the dried mixture. In step (5), the amylase is added at 5-15 U / g of starch dry weight, and the keratinase is added at 800-2000 U / g of feather protein dry weight; the amylase and keratinase are added simultaneously; the amylase is a high-temperature-resistant α-amylase, and the keratinase is a keratinase from Bacillus subtilis.

4. The method of claim 1, wherein the feed additive is prepared by the steps of: a) mixing the feather hydrolysate with a feed additive carrier; b) drying the mixture; and c) milling the dried mixture. In step (6), centrifugal separation is used for solid-liquid separation.

5. The method of claim 1, wherein the feed additive is prepared by the steps of: a) mixing the feather hydrolysate with a feed additive carrier; b) drying the mixture; and c) milling the dried mixture. In step (6), reverse osmosis membrane concentration is used for concentration, and the concentration is increased to 20-30 wt%.

6. The method of claim 1, wherein the feed additive is prepared by the steps of: a) mixing the feather hydrolysate with a feed additive carrier; b) drying the mixture; and c) milling the dried mixture. In step (6), the spray drying parameters are: inlet air temperature 160-180℃, outlet air temperature 70-85℃, and material flow rate 20-40 L / h.

7. The method of claim 1, wherein the feed additive is prepared by the steps of: a) mixing the feather hydrolysate with a feed additive carrier; b) drying the mixture; and c) milling the dried mixture to a desired particle size. In step (6), the enzyme inactivation parameters are: heating the hydrolyzed material to 80-85℃ for 10-15 min.

8. The method of claim 1, wherein the feed additive is prepared by the steps of: a) mixing the feather hydrolysate with a feed additive carrier; b) drying the mixture; and c) milling the dried mixture to a desired particle size. In step (6), the anti-caking agent is a mixture of silicon dioxide and calcium phosphate at a mass ratio of 1:1, and the antioxidant is ethoxyquin or BHT.

9. A feed additive using feather hydrolysate, characterized by, The feed additive is prepared by the method described in any one of claims 1-8.

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