Special preservative paper for poultry eggs as well as preparation method and application of special preservative paper

Abstract

The invention belongs to the technical field of agricultural product preservation, and discloses preservative paper special for poultry eggs, a preparation method and application. The special preservative paper for the poultry eggs comprises the following three layers of composite structures: a surface layer for loading a quick-release antibacterial agent; the middle layer is of a honeycomb structure and is filled with a slow-release preservative; the bottom layer is an embossed hydrophobic layer, and the contact angle is larger than or equal to 110 degrees; wherein the base paper carrier with the three-layer composite structure comprises the following components: cotton fiber modified pulp and plant pulp. Through the synergistic effect of the three-layer composite structure design and the natural plant fibers, the special preservative paper for the poultry eggs synchronously achieves the effects of broad-spectrum antibiosis, long-acting corrosion prevention and water reverse osmosis prevention, and under the condition that normal exchange of metabolic micromolecular substances such as oxygen and carbon dioxide between contents of the poultry eggs and the outside is not affected, the preservation effect is good, and the service life of the poultry eggs is prolonged. The problems that microorganisms are easy to breed and the humidity is unbalanced in the fresh-keeping process of various poultry eggs are effectively solved, and the quality stability of egg products in the storage period is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of agricultural product preservation technology, specifically relating to a special preservation paper for poultry eggs, its preparation method, and its application. Background Technology

[0002] Poultry eggs are a highly nutritious food rich in protein, fat, and various trace elements. However, they are extremely susceptible to quality deterioration during storage and distribution due to microbial contamination and humidity imbalances. For example, the natural pores on the surface of fresh eggshells make them vulnerable to invasion by pathogenic bacteria such as E. coli and Salmonella, leading to spoilage. Simultaneously, the continuous evaporation of moisture during storage increases weight loss, causing the egg white to thin and the texture to deteriorate. Century eggs, due to their processing, create an alkaline environment (pH 9-10), where continuous alkaline reactions and moisture production occur inside the egg, making them prone to the growth of molds such as Penicillium. Furthermore, the condensation of moisture on the eggshell surface accelerates microbial growth, leading to flavor deterioration and even spoilage.

[0003] Traditional methods of preserving poultry eggs are typically only applicable to specific egg types and have significant limitations. For example, fresh eggs are often coated with materials such as paraffin wax and mineral oil to physically isolate and block microorganisms; while preserved eggs generally rely on wrapping them with materials such as lime, yellow mud, and straw to delay spoilage through an alkaline environment. However, these methods not only fail to simultaneously inhibit multiple microorganisms such as bacteria and mold, but also lack a sustainable preservative mechanism. More importantly, these preservation methods often completely seal the pores of the eggshell, hindering the normal exchange of small molecules such as moisture and carbon dioxide between the egg and the external environment. This leads to the accumulation of large amounts of water droplets and moisture on the inside of the eggshell, which not only severely affects the original flavor of the egg but also accelerates its spoilage process. Therefore, developing a preservation method that combines highly effective antibacterial, long-lasting preservative, and precise moisture control functions, and is adaptable to the characteristics of various types of poultry eggs, is key to solving the poultry egg preservation problem and is of great significance for improving the economic benefits of the poultry egg industry and food safety levels.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a special preservation paper for poultry eggs, its preparation method, and its application. This special preservation paper for poultry eggs comprises a three-layer composite structure and is used for the preservation of various types of poultry eggs. It can inhibit various common pathogenic bacteria such as bacteria and molds, and achieve long-term preservation and moisture absorption, effectively extending the shelf life of poultry eggs. To achieve the above objective, the first technical solution adopted by the present invention is as follows: A special preservation paper for poultry eggs, characterized by comprising the following three-layer composite structure: Surface layer: Loaded with immediate-release antibacterial agent; Middle layer: honeycomb structure, filled with slow-release preservatives; and Bottom layer: Embossed hydrophobic layer with a contact angle ≥110°; The base paper carrier of the three-layer composite structure includes cotton fiber modified pulp and plant pulp.

[0006] Preferably, the preparation method of the cotton fiber modified slurry is as follows: cotton fibers are placed in a hydrochloric acid solution for high-pressure treatment, then washed with water to remove hydrochloric acid residue, and then pulped with water.

[0007] Preferably, the method for preparing the plant pulp is as follows: shrubs and bamboo are mixed in a mass ratio of 3:4 to 4:7, soaked in warm water, and then ground into pulp.

[0008] Preferably, the components of the immediate-release antibacterial agent include lysozyme, nisin, and potassium sorbate.

[0009] Preferably, the components of the sustained-release preservative include: β-cyclodextrin, ε-polylysine, natamycin, dehydroacetic acid, and sodium carboxymethyl cellulose.

[0010] The second technical solution adopted in this invention is: A method for preparing a special preservation paper for poultry eggs includes the following steps: Cotton fiber modified pulp and plant pulp were mixed at a mass ratio of 1:0.7-1 and then enzymatically hydrolyzed to obtain paper pulp. The pulp is made into base paper, and a surface layer is obtained by spraying an instant-release antibacterial agent. After dehydration and shaping of the pulp, it is dried in a micro-corrugated manner to obtain honeycomb base paper. The intermediate layer is obtained by vacuum impregnation and filling with a slow-release preservative. Add rice bran oil emulsion to the pulp, form it into base paper, and then emboss it to obtain a bottom layer with a contact angle ≥110°. The surface layer, intermediate layer and bottom layer are stacked in a wet state and then subjected to gradient hot pressing curing treatment.

[0011] Preferably, the vacuum degree of the vacuum impregnation is -0.08 to -0.06 MPa, and the time is 30-60 s.

[0012] Preferably, the gradient hot-press curing treatment is performed at a pressure of 0.15-0.2 MPa and at temperatures of 50-55℃, 65-70℃, and 85-90℃, for 20-30 seconds at each temperature.

[0013] The third technical solution adopted in this invention is: The application of the above-mentioned special preservation paper for poultry eggs, or the special preservation paper for poultry eggs prepared according to the above-mentioned preparation method for poultry egg special preservation paper, in the preservation of poultry eggs.

[0014] Preferably, the poultry eggs include fresh eggs and preserved eggs.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention is the first to propose the use of preservation paper for poultry egg preservation. The special preservation paper for poultry eggs provided achieves broad-spectrum antibacterial, long-lasting antiseptic, and moisture-proof effects through a three-layer composite structure design and the synergistic effect of natural plant fibers. Without affecting the normal exchange of oxygen, carbon dioxide and other metabolic small molecules between the contents of poultry eggs and the outside world, it can effectively solve the problems of easy growth of microorganisms and humidity imbalance during poultry egg preservation.

[0016] 2. The poultry egg preservation paper provided by this invention has a base paper carrier and antibacterial and preservative components that are all natural or food-grade, with no added chemical synthetic substances. It poses no safety risk when in contact with poultry eggs and meets food safety requirements.

[0017] 3. In the preparation method provided by this invention, vacuum impregnation treatment enables the slow-release preservative to be efficiently filled into the base paper while protecting the integrity of the base paper structure; gradient hot-pressing curing treatment enhances the bonding force between each layer of base paper while avoiding the reduction of the activity of functional components in the preservation paper. The synergistic effect of each process ensures that the preservation paper has comprehensive properties of high-efficiency antibacterial, long-lasting anti-corrosion and stable hydrophobicity, making it feasible for industrialization.

[0018] 4. The special preservation paper for poultry eggs provided by this invention can be widely used in the preservation, storage and circulation of various poultry eggs such as fresh eggs and preserved eggs. It can effectively improve the rate of good eggs, reduce the weight loss rate, and ensure the stability of egg quality. It provides reliable technical support for the quality improvement of the poultry egg industry and has good market application prospects. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0020] The first embodiment provided by the present invention is as follows: A special preservation paper for poultry eggs comprises the following three-layer composite structure: Surface layer: Loaded with immediate-release antibacterial agent; Middle layer: honeycomb structure, filled with slow-release preservatives; and Bottom layer: Embossed hydrophobic layer with a contact angle ≥110°; The base paper carrier of the three-layer composite structure includes cotton fiber modified pulp and plant pulp.

[0021] In this embodiment, the outer layer of the special preservation paper for poultry eggs, serving as the outermost layer in direct contact with the eggs, carries a fast-release antibacterial agent that rapidly releases its active ingredients upon initial contact with the eggs, quickly inhibiting microorganisms initially adhering to the eggshell surface. This solves the problem of "initial contamination" in egg preservation and establishes the first antibacterial barrier. The honeycomb-structured middle layer combines "storage" and "slow-release" functions. On one hand, the pores can absorb moisture generated by the eggs' respiration, preventing condensation on the eggshell surface. On the other hand, the slow-release preservatives, through slow release, continuously inhibit microbial growth, achieving long-term preservation and forming the second layer of protection. The embossed, hydrophobic bottom layer blocks the intrusion of moisture from the external environment and prevents moisture adsorbed in the middle layer from seeping back to the egg surface, preventing the eggshell from becoming damp and moldy, thus achieving "moisture-proof and freshness-locking" and forming the third barrier. The above three-layer composite structure simultaneously achieves broad-spectrum antibacterial, long-lasting preservation, and prevention of moisture back-seepage effects.

[0022] It should be noted that the above effects depend on the specific base paper carrier used in this embodiment. Existing base paper carriers mostly use a single fiber, making it difficult to balance antibacterial / preservative loading capacity with mechanical strength. The base paper carrier used in this embodiment comprises cotton fiber modified pulp and plant pulp. The cotton fiber modified pulp imparts high hydrophilicity and softness to the base paper carrier, enhancing its adsorption capacity for antibacterial / preservatives. The plant pulp provides excellent mechanical properties, and its retained natural antibacterial components synergistically interact with the adsorbed antibacterial / preservatives. This combination ensures both the loading capacity of the preservation paper for both immediate-release and slow-release antibacterial agents and good mechanical strength, thus enabling long-term preservation of poultry eggs.

[0023] It should be further explained that the preparation method of the cotton fiber modified sizing agent is as follows: the cotton fiber is placed in a hydrochloric acid solution for high-pressure treatment, followed by washing with water to remove hydrochloric acid residue, and then pulping with water. The concentration of the hydrochloric acid solution is 6-8%, and the amount used is 6-8 times the amount of cotton fiber; the pressure of the high-pressure treatment is 1.2-1.6 MPa, the temperature is 75-80 ℃, and the time is 1-1.5 h; the number of water washes can be adjusted according to the effect of hydrochloric acid residue removal, usually 3-4 times, to ensure complete removal of hydrochloric acid residue; during pulping, the amount of water used is 1.5-1.6 times the amount of cotton fiber.

[0024] The preparation method of plant pulp is as follows: Shrubs and bamboo are mixed in a mass ratio of 3:4 to 4:7, soaked in warm water, and then ground. Both the shrubs and bamboo are selected from species with certain natural antibacterial components and suitable for preparing base paper. For example, the shrubs are selected from Vitex negundo, Pyracantha fortuneana, Rosa laevigata, and Fraxinus chinensis; the bamboo is selected from Phyllostachys edulis, Phyllostachys aurea, and Phyllostachys nigra. The warm water temperature should be maintained at 45-50℃, and the amount used should be based on a solid content of 55-60% in the resulting pulp. The soaking time in warm water is 8-12 hours. It is understood that the process of grinding also includes removing impurities.

[0025] The immediate-release antibacterial agent comprises lysozyme, nisin, and potassium sorbate. The preparation method is as follows: lysozyme, nisin, and potassium sorbate are mixed at a mass ratio of 1:1.8-2.2:0.8-1.2. Then, 5-8 times the total mass of the mixture is added to an ethanol solution. The mixture is stirred at 30-35°C until completely dissolved, yielding a stable immediate-release antibacterial agent. The concentration of the ethanol solution is 8-10%.

[0026] The sustained-release preservative comprises β-cyclodextrin, ε-polylysine, natamycin, dehydroacetic acid, and sodium carboxymethyl cellulose in a mass ratio of 5-8:0.5-0.8:0.2-0.3:0.3-0.5:0.8-1.2. The preparation method is as follows: β-cyclodextrin is dissolved in 8-10 times its weight of water and stirred at 50-55 °C until completely dissolved. Then, ε-polylysine and natamycin are added, and the mixture is heated to 60-65 °C and stirred at 700-800 rpm for 30-40 min to ensure the active ingredients fully enter the β-cyclodextrin cavity. Next, dehydroacetic acid and sodium carboxymethyl cellulose are added, and the mixture is stirred evenly at 40-45 °C. The mixture is then refrigerated at 0-4 °C for 18-24 h, and the precipitate is collected by centrifugation and dried to obtain the sustained-release preservative. Conventional methods such as hot air drying, spray drying, and vacuum freeze drying are all acceptable for drying, with spray drying being preferred.

[0027] The second embodiment of the present invention is a method for preparing the above-mentioned special preservation paper for poultry eggs, comprising the following steps: Cotton fiber modified pulp and plant pulp were mixed at a mass ratio of 1:0.7-1 and then enzymatically hydrolyzed to obtain paper pulp. The pulp is made into base paper, and a surface layer is obtained by spraying an instant-release antibacterial agent. After dehydration and shaping of the pulp, it is dried in a micro-corrugated manner to obtain honeycomb base paper. The intermediate layer is obtained by vacuum impregnation and filling with a slow-release preservative. Add rice bran oil emulsion to the pulp, form it into base paper, and then emboss it to obtain a bottom layer with a contact angle ≥110°. The surface layer, intermediate layer and bottom layer are stacked in a wet state and then subjected to gradient hot pressing curing treatment.

[0028] In this embodiment, the purpose of enzymatic hydrolysis is to decompose the protein and starch residues in the pulp, reduce impurities in the base paper, and improve its cleanliness and softness. The specific method is as follows: add 0.1-0.2% by weight of protease and 0.4-0.5% by weight of amylase to the mixed pulp, treat it at 65-70℃ and pH 6.6-6.8 for 35-40 min, and then inactivate the enzymes at 90-95℃ for 15-20 min.

[0029] Vacuum impregnation is the core process for filling the intermediate layer with slow-release preservatives. Vacuum impregnation can quickly remove air from the pores of the honeycomb base paper, allowing slow-release preservatives such as ε-polylysine embedded in β-cyclodextrin to fully penetrate into the pores, achieving a filling rate of over 90%. At the same time, it reduces the contact between the preservative components and air, lowering the risk of oxidative deactivation and thus ensuring the long-term anti-corrosion capability of the intermediate layer.

[0030] The vacuum impregnation process involves a vacuum level of -0.08 to -0.06 MPa and a duration of 30-60 seconds. These parameters prevent the honeycomb base paper from collapsing due to prolonged high pressure or excessive negative pressure, thus preserving the high porosity of the base paper and providing ample space for subsequent moisture absorption by the preservation paper and the slow release of preservatives.

[0031] In the preparation of the base layer, the addition of rice bran oil emulsion to the pulp serves to form a continuous hydrophobic film on the surface of the base paper. Combined with the embossed structure, this effectively prevents external moisture intrusion and backflow of moisture adsorbed in the intermediate layer onto the egg surface. The preparation method of the rice bran oil emulsion is as follows: add 0.03-0.05% by weight of modified soybean lecithin and 0.1-0.15% by weight of sucrose fatty acid ester to rice bran oil, and mix thoroughly. The amount of rice bran oil emulsion used is 0.4-0.6% by weight of the pulp.

[0032] Gradient hot-press curing is a key process for achieving the three-layer composite structure. It simultaneously solidifies the bottom embossed structure, cures the middle honeycomb structure, and ensures strong adhesion between the surface antibacterial agent and fibers. Furthermore, it promotes hydrogen bonding and physical interlocking between the three wet-state paper fibers, enhancing interlayer adhesion and preventing delamination during storage or use. More importantly, the gradient temperature avoids the deactivation of functional components or structural damage caused by high temperatures, ensuring the antibacterial and preservative effects of the preservation paper. Specifically, the gradient hot-press curing process involves a pressure of 0.15-0.2 MPa and temperatures of 50-55℃, 65-70℃, and 85-90℃, respectively, for 20-30 seconds at each temperature.

[0033] It should be noted that in the surface preparation, the spraying amount of the immediate-release antibacterial agent is 8-9 g / m². 2In the preparation of the intermediate layer, the slow-release preservative needs to be prepared into a suspension first, and then filled into the honeycomb base paper by vacuum impregnation. The filling amount of the slow-release preservative is 10-12 g / m³. 2 The papermaking, dehydration and shaping, and micro-corrugated drying processes in the preparation method are all conventional papermaking processes. This embodiment does not impose any special limitations, and those skilled in the art can make conventional selections or adjustments based on experience or actual conditions.

[0034] The third embodiment of the present invention is the application of the above-mentioned special preservation paper for poultry eggs, or the special preservation paper for poultry eggs prepared according to the above-mentioned preparation method for special preservation paper for poultry eggs, in the preservation of poultry eggs.

[0035] It should be noted that traditional preservation techniques such as coating or wrapping with lime or mud are not only limited in their applicability and cannot meet the needs of various egg products, but also, by completely sealing the pores of the eggshell, hinder the normal exchange of small molecules such as moisture and carbon dioxide between the egg and the external environment, thus accelerating the spoilage process. This embodiment proposes for the first time to preserve eggs using preservation paper. This preservation method does not affect the normal exchange of small metabolic molecules such as oxygen and carbon dioxide between the contents of the egg and the external environment, and can be widely applied to the preservation of various types of eggs, including fresh eggs and preserved eggs. It can effectively improve the rate of good eggs and reduce weight loss, thereby effectively ensuring the quality stability of eggs during storage.

[0036] To further illustrate the technical solution of the present invention, embodiments for implementing the present invention and corresponding comparative examples will be disclosed below to demonstrate the relevant technical effects of the present invention.

[0037] All raw materials used in the embodiments of this invention were purchased from the market.

[0038] Example 1: Preparation of Special Preservative Paper for Poultry Eggs Raw material processing: Cotton fibers were placed in a 6% hydrochloric acid solution and subjected to high pressure treatment at 1.2 MPa and 75 ℃ for 1 h. After washing with water to remove hydrochloric acid residue, water was added in 1.5 times the weight of cotton to pulp the fibers, thus obtaining modified cotton fiber pulp. Mix Vitex negundo and moso bamboo at a mass ratio of 3:4, soak in 45℃ warm water for 8 hours, and then grind into a pulp to obtain a plant pulp with a solid content of 55%. Lysozyme, nisin, and potassium sorbate were mixed in a mass ratio of 1:1.8:0.8, and an ethanol solution (concentration of 8%) with a mass of 8 times the total mass of the mixture was added. The mixture was stirred at 30°C until completely dissolved to obtain an immediate-release antibacterial agent. β-cyclodextrin, ε-polylysine, natamycin, dehydroacetic acid, and sodium carboxymethyl cellulose were prepared in a mass ratio of 8:0.5:0.2:0.3:0.8. β-cyclodextrin was dissolved in 8 times its mass of water and stirred at 50 °C until completely dissolved. ε-polylysine and natamycin were then added, and the mixture was heated to 65 °C and stirred at 700 rpm for 30 min. Dehydroacetic acid and sodium carboxymethyl cellulose were then added and mixed evenly at 40 °C. The mixture was then refrigerated at 4 °C for 18 h, and the precipitate was collected by centrifugation and spray-dried to obtain a slow-release preservative. Add 0.03% of modified soybean lecithin and 0.1% of sucrose fatty acid ester by weight to rice bran oil and mix thoroughly to obtain rice bran oil emulsion.

[0039] Preparing food preservation paper: Cotton fiber modified pulp and plant pulp were mixed at a mass ratio of 1:0.7. 0.1% protease and 0.4% amylase by mass of the mixed pulp were added. The mixture was enzymatically hydrolyzed at 65 ℃ and pH 6.6 for 35 min, and then the enzyme was inactivated at 90 ℃ for 15 min to obtain pulp. The pulp is made into base paper, and then sprayed with a fast-release antibacterial agent (spraying amount of 8 g / m²). 2 ) to obtain the surface layer; After dewatering and setting the pulp, it is dried using a micro-corrugation process to obtain honeycomb-shaped base paper. A slow-release preservative is prepared into a suspension and then filled into the base paper through vacuum impregnation (vacuum degree of -0.08 MPa, time of 30 s) (the filling amount of slow-release preservative is 10 g / m²). 2 ), thus obtaining the intermediate layer; Add 0.4% by weight of rice bran oil emulsion to the pulp, and after forming the base paper, emboss it to obtain a bottom layer with a contact angle ≥110°. The surface layer, middle layer and bottom layer are laminated in a wet state and then subjected to gradient hot pressing curing treatment. The treatment pressure is 0.15 MPa and the temperatures are 50℃, 65℃ and 85℃ respectively. Each of these temperatures is treated for 20 s to obtain a special preservation paper for poultry eggs.

[0040] Example 2: Preparation of Special Preservative Paper for Poultry Eggs Raw material processing: Cotton fibers were placed in a 7% hydrochloric acid solution and subjected to high pressure treatment at 1.4 MPa and 78 ℃ for 1.5 h. After washing with water to remove hydrochloric acid residue, water was added in 1.5 times the weight of cotton to pulp the fibers, resulting in modified cotton fiber pulp. Firethorn and bamboo were mixed at a mass ratio of 2:3, soaked in warm water at 48℃ for 12 hours, and then ground into a pulp to obtain a plant pulp with a solid content of 57%. Lysozyme, nisin, and potassium sorbate were mixed in a mass ratio of 1:2:1, and an ethanol solution (10% concentration) five times the total mass of the mixture was added. The mixture was stirred at 32°C until completely dissolved to obtain an immediate-release antibacterial agent. β-cyclodextrin, ε-polylysine, natamycin, dehydroacetic acid, and sodium carboxymethyl cellulose were prepared in a mass ratio of 6:0.6:0.25:0.4:1. β-cyclodextrin was dissolved in 10 times its mass of water and stirred at 53 °C until completely dissolved. ε-polylysine and natamycin were then added, and the mixture was heated to 62 °C and stirred at 750 rpm for 35 min. Dehydroacetic acid and sodium carboxymethyl cellulose were then added and mixed evenly at 42 °C. The mixture was then refrigerated at 2 °C for 20 h, and the precipitate was collected by centrifugation and spray-dried to obtain a slow-release preservative. Add 0.05% of modified soybean lecithin and 0.12% of sucrose fatty acid ester by weight to rice bran oil and mix thoroughly to obtain rice bran oil emulsion.

[0041] Preparing food preservation paper: Cotton fiber modified pulp and plant pulp were mixed at a mass ratio of 1:0.8. 0.15% protease and 0.45% amylase by mass of the mixed pulp were added. The mixture was enzymatically hydrolyzed at 70 ℃ and pH 6.7 for 38 min, and then the enzyme was inactivated at 92 ℃ for 18 min to obtain pulp. The pulp is made into base paper, and then sprayed with a fast-release antibacterial agent (spraying amount of 9 g / m²). 2 ) to obtain the surface layer; After dewatering and setting the pulp, it is dried using a micro-corrugation process to obtain honeycomb-shaped base paper. A slow-release preservative is prepared into a suspension and then filled into the base paper through vacuum impregnation (vacuum degree of -0.07 MPa, time of 45 s) (the filling amount of slow-release preservative is 11 g / m³). 2 ), thus obtaining the intermediate layer; Add 0.5% by weight of rice bran oil emulsion to the pulp, form it into base paper, and then emboss it to obtain a bottom layer with a contact angle ≥110°. The surface layer, middle layer and bottom layer are laminated in a wet state and then subjected to gradient hot pressing curing treatment. The treatment pressure is 0.18 MPa and the temperatures are 52℃, 68℃ and 88℃ respectively. Each of these temperatures is treated for 30 s to obtain a special preservation paper for poultry eggs.

[0042] Example 3: Preparation of Special Preservative Paper for Poultry Eggs Raw material processing: Cotton fibers were placed in an 8% hydrochloric acid solution and subjected to high pressure treatment at 1.6 MPa and 80 ℃ for 1.2 h. After washing with water to remove hydrochloric acid residue, water was added in 1.6 times the weight of cotton to pulp the fibers, resulting in modified cotton fiber pulp. Mix small wax tree and bamboo in a mass ratio of 4:7, soak in 50℃ warm water for 10 hours, and then grind into pulp to obtain a plant pulp with a solid content of 60%. Lysozyme, nisin, and potassium sorbate were mixed in a mass ratio of 1:2.2:1.2, and an ethanol solution (9% concentration) with a mass of 6 times the total mass of the mixture was added. The mixture was stirred at 35°C until completely dissolved to obtain an immediate-release antibacterial agent. β-cyclodextrin, ε-polylysine, natamycin, dehydroacetic acid, and sodium carboxymethyl cellulose were prepared in a mass ratio of 5:0.5:0.3:0.5:1.2. β-cyclodextrin was dissolved in 9 times its mass of water and stirred at 55 °C until completely dissolved. Then, ε-polylysine and natamycin were added, the temperature was raised to 60 °C, and the mixture was stirred at 800 rpm for 40 min. Then, dehydroacetic acid and sodium carboxymethyl cellulose were added, and the mixture was stirred evenly at 45 °C. The mixture was then refrigerated at 0 °C for 24 h. The precipitate was collected by centrifugation and freeze-dried under vacuum to obtain a slow-release preservative. Add 0.04% of modified soybean lecithin and 0.15% of sucrose fatty acid ester by weight to rice bran oil and mix thoroughly to obtain rice bran oil emulsion.

[0043] Preparing food preservation paper: Cotton fiber modified pulp and plant pulp were mixed at a mass ratio of 1:1. 0.2% protease and 0.5% amylase by mass of the mixed pulp were added. The mixture was enzymatically hydrolyzed at 68 ℃ and pH 6.8 for 40 min, and then the enzyme was inactivated at 95 ℃ for 20 min to obtain pulp. The pulp is made into base paper, and a fast-release antibacterial agent is sprayed on it (spraying amount is 10 g / m²). 2 ) to obtain the surface layer; After dewatering and setting the pulp, it is dried using a micro-corrugation process to obtain honeycomb-shaped base paper. A slow-release preservative is prepared into a suspension and then filled into the base paper through vacuum impregnation (vacuum degree of -0.06 MPa, time of 60 s) (the filling amount of the slow-release preservative is 12 g / m²). 2 ), thus obtaining the intermediate layer; Add 0.6% by weight of rice bran oil emulsion to the pulp, and after forming the base paper, emboss it to obtain a bottom layer with a contact angle ≥110°. The surface layer, middle layer and bottom layer are laminated in a wet state and then subjected to gradient hot pressing curing treatment. The treatment pressure is 0.2 MPa and the temperatures are 55℃, 70℃ and 90℃ respectively. Each of these temperatures is treated for 25 s to obtain special preservation paper for poultry eggs.

[0044] Comparative Example 1 The preparation method is the same as in Example 1, except that the cotton fiber modified sizing agent is replaced with conventional cotton fiber sizing agent. Specifically, the cotton fibers are not modified and are directly mixed with water to obtain cotton fiber sizing agent.

[0045] Comparative Example 2 The preparation method is the same as in Example 1, except that the use of cotton fiber modified pulp is omitted, and the pulp is obtained only from the enzymatic hydrolysis of plant pulp.

[0046] Comparative Example 3 The preparation method is the same as in Example 1, except that the use of plant pulp is omitted and the pulp is obtained only by enzymatic hydrolysis of cotton fiber modified pulp.

[0047] Comparative Example 4 The preparation method is the same as in Example 1, except that enzymatic hydrolysis is omitted during the pulp preparation process.

[0048] Comparative Example 5 The preparation method is the same as in Example 1, except that no fast-release antibacterial agent is sprayed during the surface preparation process.

[0049] Comparative Example 6 The preparation method is the same as in Example 1, except that no slow-release preservative is filled in the intermediate layer during the preparation process.

[0050] Comparative Example 7 The preparation method is the same as in Example 1, except that in the preparation of the intermediate layer, vacuum impregnation is replaced by conventional impregnation, that is, impregnation for 180 s under normal pressure.

[0051] Comparative Example 8 The preparation method is the same as in Example 1, except that no rice bran oil emulsion is added in the preparation of the bottom layer.

[0052] Comparative Example 9 The preparation method is the same as in Example 1, except that the gradient hot pressing curing process is replaced with conventional hot pressing curing process, that is, treatment at 0.15 MPa and 85 ℃ for 60 s.

[0053] Blank control The preservative paper uses a single fiber as its base material and is loaded with a single type of antibacterial agent. Specifically, the base material is selected from moso bamboo, whose fiber strength and moisture absorption capacity are superior to cotton and Vitex negundo. The preparation method is as follows: After soaking the bamboo in 45℃ warm water for 8 hours, it was ground into pulp to obtain a pulp with a solid content of 55%. The pulp is made into base paper, and then an instant-release antibacterial agent (spraying amount of 8 g / m2) is sprayed on it to obtain preservation paper.

[0054] Experimental Example 1 The antibacterial properties, moisture absorption capacity, and tensile strength of the preservation paper from the above examples, comparative examples, and blank control were tested using the following specific test methods: Antibacterial properties: The antibacterial ability of the preservation paper against common pathogens of poultry eggs, Escherichia coli, Staphylococcus aureus, and Penicillium, was determined by the inhibition zone method. Sterilized solid culture medium was poured into petri dishes and allowed to solidify completely. Then, 0.1 mL of Escherichia coli, Staphylococcus aureus, and Penicillium suspensions were evenly added to each dish. Sterilized preservation paper with a diameter of approximately 1 cm was placed face down on the petri dishes in a triangular arrangement. Sterilized physiological saline was used as a control group. The petri dishes were placed in a constant temperature incubator and incubated at 37 ℃ for 24 h. The diameter of the inhibition zone was measured using the cross-sectional method, and the average of three measurements was taken.

[0055] Moisture absorption capacity: The cling film was dried to constant weight (mass denoted as m0) and placed in an environment with a temperature of 25±1 ℃ and a relative humidity of 90±2% (simulating the high humidity environment for storing poultry eggs). After 24 h and 48 h, the cling film was removed, the surface water was absorbed, and the weight was recorded as m1. The moisture absorption rate at different times was calculated according to the following formula. The higher the moisture absorption rate of the cling film at 24 h, and the less significant the decrease in moisture absorption rate at 48 h, the better the effect of preventing poultry eggs from becoming damp and moldy. Moisture absorption rate (%) = (m1-m0) / m0×100%.

[0056] Tensile strength (kN / m): The higher the tensile strength of the preservation paper, the less likely it is to tear or break, and it can meet the packaging and storage requirements of various poultry eggs. The test method refers to GB / T 12914-2018 "Determination of tensile strength of paper and paperboard".

[0057] The test results of the antibacterial properties, moisture absorption capacity and tensile strength of each group of food preservation paper are shown in Table 1-2.

[0058] Table 1. Test results of antibacterial properties of food preservation paper .

[0059] Table 2. Test results of moisture absorption capacity and tensile strength of food preservation paper. .

[0060] Experimental Example 2 The preservation paper used in the examples, comparative examples, and blank control was applied to the preservation of fresh eggs, and the application method is as follows: Select fresh eggs (chicken eggs) with intact shells and no cracks, gently rinse the surface stains with clean water, and let them air dry naturally; Cut the cling film into squares with sides of 15-20 cm. Place a single fresh egg in the center of the cling film (in the examples and comparative examples, the surface of the cling film should be facing inwards to contact the eggshell). Wrap the egg using a diagonal wrapping method so that the paper completely adheres to the surface of the eggshell.

[0061] The wrapped fresh eggs were stored at 25℃ and 85% humidity for 30 days. Samples were taken to test the percentage of good eggs, weight loss, and total bacterial count on the eggshell surface to evaluate the preservation effect. Untreated fresh eggs were used as a control. The methods for measuring the indicators are as follows: Good egg rate: Observe whether the eggshell is moldy or damaged, and gently shake the egg to check if the yolk is broken. Eggs without the above phenomena are considered good eggs. Count the number of good eggs and calculate the good egg rate according to the following formula: Good egg rate (%) = number of good eggs / total number of eggs × 100%.

[0062] Weight loss rate: Calculated based on the weight of fresh eggs before and after storage, using the following formula: Weight loss rate (%) = (initial mass - post-storage mass) / initial mass × 100%; Total bacterial count: Tested according to the method in GB 2749-2015 "National Food Safety Standard for Eggs and Egg Products".

[0063] The results of the index determination of fresh eggs in each group after 30 days of storage are shown in Table 3.

[0064] Table 3. Results of index determination of fresh eggs after 30 days of storage .

[0065] As can be seen from the index measurement results in Table 3, using the special preservation paper for poultry eggs of the present invention for the preservation of fresh eggs can effectively reduce the total bacterial count and weight loss rate of fresh eggs, and significantly improve the good egg rate during the storage of fresh eggs.

[0066] Experimental Example 3 The preservation paper used in the examples, comparative examples, and blank control was applied to the preservation of preserved eggs, and the application method is as follows: Select mature preserved eggs, gently brush off any remaining mud or salt residue from the surface with a soft brush, and let them air dry naturally. Cut the cling film into squares with sides of 20-25 cm, place a single preserved egg in the center of the cling film (in the examples and comparative examples, the surface of the cling film should be facing inwards to contact the eggshell), and wrap it using a diagonal wrapping method so that the paper completely adheres to the surface of the eggshell.

[0067] The wrapped preserved eggs were stored at 25°C and 85% humidity. Samples were taken every 5 days during storage to measure the percentage of good eggs, weight loss, and total bacterial count on the eggshell surface to evaluate the preservation effect. Untreated preserved eggs served as a control. The measurement methods were the same as in Example 2.

[0068] Preservation effect: Untreated preserved eggs showed the fastest growth in total bacterial count during storage, exhibiting a linear increase in the first 30 days. By day 60, the total bacterial count exceeded the national standard, and the weight loss rate increased to 6.82%, indicating complete spoilage and inedibility. Preserved eggs treated with the preservation paper (as a blank control) exceeded the national standard by approximately day 75, with a weight loss rate of 5.8%, indicating spoilage. Preserved eggs treated with the preservation paper (as a comparative example) exceeded the national standard by day 73-88, with a weight loss rate between 3-5%, indicating complete spoilage. However, preserved eggs treated with the preservation paper of this invention did not exceed the national standard by day 105, with a weight loss rate of only 2-3%, demonstrating a significantly improved preservation effect compared to other treatment groups.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A special preservation paper for poultry eggs, characterized in that, It includes the following three-layer composite structure: Surface layer: Loaded with immediate-release antibacterial agent; Middle layer: honeycomb structure, filled with slow-release preservatives; and Bottom layer: Embossed hydrophobic layer with a contact angle ≥110°; The base paper carrier of the three-layer composite structure includes cotton fiber modified pulp and plant pulp.

2. The special preservation paper for poultry eggs as described in claim 1, characterized in that, The preparation method of the modified cotton fiber pulp is as follows: cotton fibers are placed in a hydrochloric acid solution for high-pressure treatment, then washed with water to remove hydrochloric acid residue, and then pulped with water.

3. The special preservation paper for poultry eggs as described in claim 1, characterized in that, The method for preparing the plant pulp is as follows: shrubs and bamboo are mixed in a mass ratio of 3:4 to 4:7, soaked in warm water, and then ground into pulp.

4. The special preservation paper for poultry eggs as described in claim 1, characterized in that, The components of the immediate-release antibacterial agent include lysozyme, nisin, and potassium sorbate.

5. The special preservation paper for poultry eggs as described in claim 1, characterized in that, The components of the sustained-release preservative include: β-cyclodextrin, ε-polylysine, natamycin, dehydroacetic acid, and sodium carboxymethyl cellulose.

6. A method for preparing a special preservation paper for poultry eggs, characterized in that, Includes the following steps: Cotton fiber modified pulp and plant pulp were mixed at a mass ratio of 1:0.7-1 and then enzymatically hydrolyzed to obtain paper pulp. The pulp is made into base paper, and a surface layer is obtained by spraying an instant-release antibacterial agent. After dehydration and shaping of the pulp, it is dried in a micro-corrugated manner to obtain honeycomb base paper. Then, it is filled with a slow-release preservative through vacuum impregnation to obtain the middle layer. Add rice bran oil emulsion to the pulp, form it into base paper, and then emboss it to obtain a bottom layer with a contact angle ≥110°. The surface layer, intermediate layer and bottom layer are stacked in a wet state and then subjected to gradient hot pressing curing treatment.

7. The preparation method according to claim 6, characterized in that, The vacuum impregnation process involves a vacuum level of -0.08 to -0.06 MPa and a duration of 30 to 60 seconds.

8. The preparation method according to claim 6, characterized in that, The gradient hot-press curing process is performed at a pressure of 0.15-0.2 MPa and at temperatures of 50-55℃, 65-70℃, and 85-90℃, for 20-30 seconds at each temperature.

9. The application of the special preservation paper for poultry eggs prepared by the method of preparing the special preservation paper for poultry eggs according to any one of claims 1-5, or according to any one of claims 6-8, in the preservation of poultry eggs.

10. The application as described in claim 9, characterized in that, The eggs include fresh eggs and preserved eggs.