Eggshell coating composition and egg coated therewith

Abstract

The present invention relates to an eggshell coating composition comprising a cationic polysaccharide polymer, pullulan, a polyphenol compound, and a polyvalent metal salt, and to an egg coated therewith. The eggshell coating composition according to the present invention exhibits low gas permeability and excellently preserves the freshness of eggs. Moreover, since the components used in the composition are naturally derived, the composition is environmentally friendly. In addition, since the coating layer demonstrates high adhesion, the eggshell coating composition effectively maintains the freshness of washed eggs and prevents the penetration of pathogens, thus being advantageous for long-term storage.

Description

Eggshell coating composition and eggs coated therewith

[0001] The present invention relates to an eggshell coating composition for maintaining the freshness of eggs and eggs coated with the same.

[0002] Eggs are a vital source of protein in the diet, and their consumption remains a constant staple. Recent research has revealed that the eggshell is an inorganic-organic hybrid structure composed of an inorganic calcium carbonate shell and an organic egg membrane composed of protein. Specifically, the organic eggshell membrane is a thin membrane approximately 70 micrometers thick, largely composed of two layers: an inner membrane and an outer membrane. This membrane is known to be a natural composite structure.

[0003] The dense meshwork of the eggshell membrane prevents extra-intestinal pathogenic bacteria such as Salmonella, Escherichia coli, Enterobacter, and Klesiella from penetrating the egg. However, due to the risk of pathogenic bacteria and hygiene issues, the eggshell undergoes a washing and sterilization process. During this process, the cuticle membrane easily dissolves, making the egg vulnerable to pathogenic bacteria, and this has become a factor threatening the freshness and safety of the egg.

[0004] Washing eggs removes the outermost cuticle layer, exposing the eggs to contamination by pathogenic bacteria. Furthermore, the protective layer preventing oxygen from entering the egg is lost, accelerating oxidation and lowering egg freshness. Furthermore, washing eggs are prone to condensation due to temperature changes, which can accelerate oxidation and the growth of pathogenic bacteria.

[0005] Accordingly, research is actively being conducted on biocompatible nano / micro coating technology to maintain the freshness of washed eggs during distribution, and there is a need for research on eco-friendly technology that is inexpensive and satisfies food safety standards for materials used in coating formation.

[0006] [Prior Art Literature]

[0007] (Patent Document 1) Republic of Korea Patent Gazette No. 10-1998266

[0008] The present invention aims to provide a coating composition for eggshells containing a pullulan and a polyphenol compound, which can maintain the freshness of washed eggs by coating the eggshells, while imparting antibacterial properties to the eggs, thereby preventing pathogenic bacteria and oxidation of the eggs.

[0009] The present invention provides an eggshell coating composition comprising a cationic polysaccharide polymer, pullulan, a polyphenol compound, and a polyvalent metal salt.

[0010] According to one example of the present invention, the cationic polysaccharide polymer may be chitosan or chitin.

[0011] According to one example of the present invention, the polyphenol compound may be a tannin compound.

[0012] According to one example of the present invention, the tannin compound may be at least one selected from the group consisting of tannic acid (TA), gallic acid, theaflavin-3-gallate, epigallocatechin gallate, and epicatechin gallate.

[0013] According to one example of the present invention, the metal of the multivalent metal salt may include a transition metal.

[0014] According to one example of the present invention, the transition metal salt may be one or a mixture of two or more selected from the group consisting of iron gluconate, ferrous fumarate, iron lactate, ferrous sulfate, iron citrate, ammonium ferric citrate, iron phosphate, ferric pyrophosphate, sodium ferric pyrophosphate, copper gluconate, copper sulfate, zinc acetate, zinc chloride, zinc gluconate, zinc oxide, zinc carbonate, zinc sulfate, chromium chloride, and ammonium molybdate.

[0015] According to one example of the present invention, the eggshell coating composition may further include water as a solvent.

[0016] According to one example of the present invention, the eggshell coating composition may contain pullulan in an amount of 3 wt% or more based on the total weight of the composition.

[0017] According to one example of the present invention, the eggshell coating composition may include the polyphenol compound:fullan in a weight ratio of 1:800 to 1:2000.

[0018] According to one example of the present invention, the eggshell coating composition may include the polyphenol compound: polyvalent metal salt in a weight ratio of 1:5 to 1:20.

[0019] According to one example of the present invention, the eggshell coating composition may include the pullulan: cationic polysaccharide in a weight ratio of 100:0.1 to 100:5.

[0020] The present invention comprises the steps of preparing a coating solution comprising an eggshell coating composition selected from any one of claims 1 to 11; and the steps of spraying or dipping the coating solution onto an eggshell and then drying it.

[0021] A method for coating an eggshell including a unit process can be provided.

[0022] According to one example of the present invention, the spray can be coated by spraying the spray through a plurality of nozzles in the upper or lower direction of the eggshell.

[0023] According to one example of the present invention, the drying can be performed at 50 to 100°C.

[0024] According to one example of the present invention, the method may further include a step of coating the surface of an eggshell coated with the above unit process with a solution containing an anionic polysaccharide; and a step of performing the above unit process on an eggshell coated with the anionic polysaccharide polymer.

[0025] The present invention can provide an egg including a coating layer in which a cationic polysaccharide polymer, pullulan, a polyphenol compound, and a polyvalent metal salt are complexed.

[0026] According to one example of the present invention, the coating layer may be formed by alternately laminating the unit coating layers, each of which comprises a first coating layer in which the cationic polysaccharide polymer, pullulan, a polyphenol-based compound, and a polyvalent metal salt are combined, and a second coating layer comprising an anionic polysaccharide polymer positioned on the first coating layer.

[0027] The coating composition according to the present invention is an environmentally friendly coating composition that is effective in preventing oxidation of eggs and the penetration of external pathogens. Furthermore, the coating composition has low gas permeability, which allows it to maintain excellent freshness in eggs. Furthermore, the composition is environmentally friendly because its components are of natural origin. Furthermore, its coating layer has high retention strength, making it advantageous for long-term storage of washed eggs.

[0028] Figure 1 is a graph showing the change in mass of eggs coated with an eggshell coating composition containing 7 wt% of pullulan based on the total weight and eggs without a coating agent.

[0029] The embodiments described herein may be modified in various ways, and the technology according to one embodiment is not limited to the embodiments described below. Furthermore, the embodiments of one embodiment are provided to more fully explain the present disclosure to those of ordinary skill in the art.

[0030] Additionally, the singular forms used in the specification and the appended claims are intended to include the plural forms as well, unless the context clearly dictates otherwise.

[0031] Additionally, the numerical ranges used herein include lower and upper limits and all values ​​within that range, increments logically derived from the shape and width of the defined range, all doubly defined values, and all possible combinations of upper and lower limits of numerical ranges defined in different shapes. Unless otherwise specifically defined in the specification of the present invention, values ​​outside the numerical range that may arise due to experimental error or rounding of values ​​are also included in the defined numerical range.

[0032] Furthermore, reference to an element "including" throughout the specification does not exclude other elements, but rather includes other elements, unless specifically stated otherwise.

[0033] Hereinafter, specific examples and experimental examples will be described. However, the examples and experimental examples described below are only illustrative, and the technology described in this specification is not limited thereto.

[0034] The eggshell is an inorganic-organic hybrid complex comprising an organic eggshell composed of calcium carbonate minerals and proteins. The organic eggshell has a dense mesh structure that prevents oxidation of the egg and prevents the penetration of external pathogens. However, when washing eggs, the cuticle layer on the outermost layer of the eggshell is removed, exposing the egg to contamination by pathogenic bacteria and causing oxidation of the egg, which reduces its freshness. Therefore, the inventors of the present invention have developed an eggshell coating composition that is environmentally friendly, maintains the freshness of eggs, and imparts antibacterial properties.

[0035] The present invention provides an eggshell coating composition comprising a cationic polysaccharide polymer, pullulan, a polyphenol compound, and a polyvalent metal salt.

[0036] The eggshell coating composition according to the present invention has an advantage in film formation compared to a coating formed with a polyphenol compound and a polyvalent metal salt, and the coating has a long-lasting effect by forming a coating complex, thereby providing a coating layer that is suitable for long-term storage of eggs while also being most suitable for antibacterial properties and freshness maintenance. Conventional eggshell coating compositions only contain polyphenol compounds and polyvalent metal salts, forming a thin coating that is easily physically removed, whereas the eggshell coating composition according to the present invention contains a polyphenol compound, a polyvalent metal salt, pullulan, and a cationic polysaccharide, thereby maintaining the coating for a long period of time and maintaining the freshness of eggs.

[0037] The above pullulan is a natural polysaccharide, a neutral natural polysaccharide and a metabolite of the yeast Aureobasidium pullulans. Pullulan is a linear polysaccharide formed by alpha-1,6-glycosidic bonds of maltotriose, which is formed by alpha-1,4-glycosidic bonds. Pullulan is a biomaterial that is biodegradable and has high safety, so when included as a component of an eggshell coating composition, it can provide high food safety to eggs. In particular, pullulan imparts excellent film-forming ability to the eggshell coating composition, and can organically combine with cationic polysaccharide polymers, polyphenol compounds, and polyvalent metal salts to provide the film formed after drying with excellent oxygen barrier ability. Accordingly, it can perform an antioxidant function essential for maintaining egg freshness and provide a coating layer with high long-term retention.

[0038] The cationic polysaccharide polymer may be chitosan or chitin, but is not limited thereto. Any polysaccharide polymer having cationic properties may be used as the cationic polysaccharide polymer without particular limitation, and preferably, it may be a natural cationic polysaccharide polymer. As a specific example, the cationic polysaccharide polymer may be any one selected from the group consisting of chitosan, chitin, (C1-C6) alkylamino (C1-C6) alkyl cellulose, (C1-C6) alkylamino (C1-C6) alkyl dextran, and salts thereof, or a mixture of two or more thereof, but is not necessarily limited thereto. Most preferably, chitosan or chitin is suitable in that it can eliminate pathogenic bacteria through antibacterial action together with a polyphenol compound.

[0039] The polyphenol compound may be, but is not limited to, a tannin compound. The tannin compound may be at least one selected from the group consisting of tannic acid, gallotannin, ellagitannins, tannic acid (TA), gallic acid, theaflavin-3-gallate, epigallocatechin gallate, and epicatechin gallate.

[0040] The metal of the above polyvalent metal salt is not limited as long as it can form a coating complex with the polyphenol compound and the pulverin, but is preferably a transition metal. The metal of the above polyvalent metal salt may be any one selected from the group consisting of aluminum (Al), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), cadmium (Cd), and lanthanides, or a mixture of two or more thereof.

[0041] The above transition metal salt may be one or a mixture of two or more selected from the group consisting of iron gluconate, ferrous fumarate, iron lactate, ferrous sulfate, iron citrate, ammonium ferric citrate, iron phosphate, ferric pyrophosphate, sodium ferric pyrophosphate, copper gluconate, copper sulfate, zinc acetate, zinc chloride, zinc gluconate, zinc oxide, zinc carbonate, zinc sulfate, chromium chloride, and ammonium molybdate.

[0042] According to one example of the present invention, the eggshell coating composition may be provided in an aqueous solution state by further including water as a solvent. Since all of the components included in the eggshell coating composition are water-soluble, the eggshell coating composition in the aqueous solution state may be provided as a transparent, uniform solution, thereby enabling a uniform solution coating on the eggshell.

[0043] The above eggshell coating composition may contain pullulan in an amount of 3 wt% or more based on the total weight of the composition. Specifically, the pullulan may be contained in an amount of 3 wt% or more, 5 wt% or more, 7 wt% or more, and, without limitation, 20 wt% or less based on the total weight of the eggshell coating composition comprising pullulan, a polyphenol compound, a cationic polysaccharide polymer, and water. The above eggshell coating composition has remarkably excellent long-term storage characteristics because it contains pullulan in an amount of 3 wt% or more in the composition.

[0044] The above eggshell coating composition may contain a polyphenol compound: pullulan in a weight ratio of 1:500 to 1:3000, specifically, a weight ratio of 1:800 to 1:2000, more specifically, a weight ratio of 1:1000 to 1:1500. Since the polyphenol compound and pullulan are contained in the above ratio, the composition may exhibit excellent coating retention while exhibiting a high freshness retention effect for a period of 4 weeks, which is the period typically required for distribution of eggs.

[0045] The above-mentioned eggshell coating composition may include the polyphenol compound: polyvalent metal salt in a weight ratio of 1:3 to 1:30, specifically, in a weight ratio of 1:5 to 1:20, and more specifically, in a weight ratio of 1:8 to 1:15.

[0046] The above eggshell coating composition may include pullulan:cationic polysaccharide in a weight ratio of 100:0.01 to 100:20, specifically 100:0.1 to 100:5, more specifically 100:0.3 to 100:2.

[0047] By forming an eggshell coating composition containing the cationic polysaccharide polymer, polyphenol compound, pullulan, and polyvalent metal salt in the above ratio, the properties of the coating complex advantageous for imparting antibacterial properties and long-term storage can be most preferably exhibited.

[0048] In one example of the present invention, the eggshell coating composition may further include a plasticizer and an antioxidant.

[0049] The plasticizer promotes the formation of a coating film on the surface of the eggshell and helps the coating film to be uniformly coated on the eggshell. The plasticizer may be any one or a mixture of two or more selected from the group consisting of sorbitol, mannitol, glycerol, polyethylene glycol, propylene glycol, triethyl citrate, butyl citrate, acetyl triethyl citrate, acetyl tributyl citrate, diacetyl monoglyceride, and diethyl phthalate, but is not necessarily limited thereto. By adding such a plasticizer, the eggshell coating composition can be effectively coated on the surface of the eggshell, and also improves the moisture content of the egg, so that freshness can be maintained for a longer period of time.

[0050] The above antioxidant is added to prevent deterioration caused by oxygen in the air, and the above antioxidant may be one or a mixture of two or more selected from the group consisting of ascorbic acid, isoarcotic acid, erythorbic acid, glutathione, and carotenoids, but is not necessarily limited thereto.

[0051] In one example of the present invention, the eggshell coating composition may contain 0.1 to 5 wt% of a plasticizer and 0.005 to 1 wt% of an antioxidant, respectively, based on 100 wt% of the eggshell coating composition. Specifically, the composition may contain 0.1 to 5 wt% of a plasticizer and 0.005 to 1 wt% of an antioxidant based on the total weight of the eggshell coating composition, preferably 0.1 to 5 wt% of a plasticizer and 0.005 to 1 wt% of an antioxidant based on the total weight of the eggshell coating composition. In the above range, the effect of the plasticizer and the effect of the antioxidant may be excellent.

[0052] The present invention provides an eggshell coating method comprising, as a unit process, a step of preparing a coating solution containing the above-described eggshell coating composition; and a step of spraying or dipping the coating solution onto an eggshell and then drying it.

[0053] The method for coating the above-described eggshell coating composition on the eggshell may be spraying, dipping, or any conventional method without particular limitation. The spraying may be performed by spraying the eggshell through a plurality of nozzles in the upper and lower directions. Specifically, one embodiment of the spraying method may be a method of producing an aerosol composed of the eggshell coating composition through compressed air and coating the surface of the eggshell with the aerosol. Another embodiment may be a method of spraying the eggshell coating composition in liquid form through a pump and coating the surface of the eggshell. The number of nozzles for spraying or atomizing is not particularly limited as long as it is plural, and may be, for example, 1 to 10, 2 to 10, or 5 to 10, but is not limited thereto. In addition, in the spraying, the number of sprayings and the spraying time are not limited as long as a coating film is evenly and well formed on the entire eggshell. Specifically, the number of sprayings may be performed more than once, and the upper limit may be less than 10 times, but the number of times may also be adjusted differently depending on the spraying time. When the number of sprayings is 1 time, the spraying time may be 10 to 60 seconds, 20 to 50 seconds, or 30 to 40 seconds, but is not limited thereto, and a person skilled in the art may adjust the number of sprayings, etc. in consideration of the number of sprayings, in order to form an appropriate coating layer.

[0054] According to an example of the present invention, the dipping is performed by dipping an egg in a coating solution to form a coating film on the eggshell. The number of dippings and the dipping time are not limited as long as the coating film is formed evenly and evenly on the entire eggshell. Specifically, the number of dippings may be performed 1 to 10 times, 3 to 5 times, but the number of dippings may be adjusted depending on the dipping time. The dipping time is not limited, but in the case of dipping once, it may be 5 to 60 seconds, 10 to 50 seconds, or 30 to 40 seconds, but is not necessarily limited thereto.

[0055] The above eggshell coating method may include a drying step. The drying temperature may be, as a lower limit, 100°C or less, 90°C or less, or 80°C or less, and as an upper limit, 50°C or more, 60°C or more, or 70°C or more, and specifically, may be performed at 50 to 100°C, and more specifically, 60 to 80°C. The drying time may be 30 seconds to 10 minutes, or 1 minute to 5 minutes, but is not limited as long as the coating composition can be completely dried. The number of drying times may be 1 to 10 times, or 3 to 8 times, but is not limited thereto. When drying is performed multiple times, the eggs may be turned over to increase the drying efficiency of the eggs.

[0056] According to one example of the present invention, the eggshell coating method may further include a step of coating the surface of the eggshell coated with a solution containing an anionic polysaccharide as a unit process of the above-described coating method; and a step of performing the unit process with the anionic polysaccharide polymer.

[0057] The step of performing coating with a solution containing the anionic polysaccharide may use the spraying or dipping method described above, and thus, a detailed description thereof will be omitted. Since the eggshell coating method according to the present invention further includes a step of coating with a solution containing an anionic polysaccharide polymer and a step of performing the unit process with the anionic polysaccharide polymer, a second coating layer containing a cationic polysaccharide polymer may be formed on the coating layer formed on the eggshell through the unit process, that is, the first coating layer, and subsequently, a third coating layer formed through the unit process may be formed on the second coating layer. More specifically, since the first coating layer contains the cationic polysaccharide polymer, the first coating layer may have a positive charge on the surface, and since the second coating layer contains the anionic polysaccharide polymer, the first coating layer and the second coating layer may form an ionic complex. Similarly, since the second coating layer and the third coating layer have different charges, they may form an ionic complex. The coating layer according to this has a multilayer structure and has high adhesion to different coating layers, so it can have significantly low gas permeability, and thus can maintain the freshness of eggs very well.

[0058] The above second coating layer and third coating layer are merely illustrative, and since the above unit process can be performed more than once, for example, a five-layer structure including a fourth coating layer and a fifth coating layer can be formed by performing the unit process twice, and a seven-layer structure including a sixth coating layer and a seventh coating layer can be formed by performing the unit process three times. The number of layers is proportional to the number of repetitions of the unit process, and is therefore not limited to a specific number.

[0059] The above anionic polysaccharide polymer may be used without particular limitation as long as it is an anionic polysaccharide polymer, and preferably, it may be a natural anionic polysaccharide polymer. As a specific example, the anionic polysaccharide polymer is gum arabic, ghatti gum, guar gum, xanthan gum, gellan gum, tara gum, konjac gum, karaya gum, tamarind gum, tragacanth gum, locust bean gum, carrageenan, furcellaran, curdlan, gellan, alginic acid, pectin, carrageenan, hyaluronic acid, carboxy(C1-C6)alkyl cellulose, sulfo(C1-C6)alkyl cellulose, carboxy(C1-C6)alkyl hydroxy(C1-C6)alkyl cellulose, carboxy(C1-C6)alkyl sulfo(C1-C6)alkyl cellulose, hydroxy(C1-C6)alkyl sulfo(C1-C6)alkyl cellulose, cellulose sulfate, cellulose phosphate, chondroitin sulfate, dextran sulfate, dextrin sulfate, and salts thereof. It may be one or more selected from the group consisting of:

[0060] According to an example of the present invention, the solution containing the anionic polysaccharide polymer may be an aqueous solution, and the concentration of the anionic polysaccharide polymer in the solution may be an upper limit of 0.5 wt% or less, 0.4 wt% or less, and a lower limit of 0.05 wt% or more, 0.1 wt% or more. Specifically, the concentration of the anionic polysaccharide polymer may be 0.05 to 0.5 wt%, and more specifically, 0.1 to 0.4 wt%.

[0061] The present invention also provides an egg comprising a coating layer in which a cationic polysaccharide polymer, pullulan, a polyphenol compound, and a polyvalent metal salt are complexed.

[0062] In one example of the present invention, the coating layer may include a first coating layer in which the cationic polysaccharide polymer, pullulan, a polyphenol-based compound, and a polyvalent metal salt are complexed, and a second coating layer including an anionic polysaccharide polymer positioned on the first coating layer.

[0063] In one example of the present invention, the coating layer may be a first coating layer in which the cationic polysaccharide polymer, pullulan, a polyphenol-based compound, and a polyvalent metal salt are complexed, and a second coating layer including an anionic polysaccharide polymer positioned on the first coating layer may be alternately laminated as unit coating layers. When the unit coating layers are alternately laminated, it is preferable that the outermost layer be a coating layer in which the cationic polysaccharide polymer, pullulan, a polyphenol-based compound, and a polyvalent metal salt are complexed.

[0064] Hereinafter, specific examples and experimental examples will be described. However, the examples and experimental examples described below are only illustrative, and the technology described in this specification is not limited thereto.

[0065]

[0066] (Example 1)

[0067] <Manufacturing of coating solution>

[0068] Ultrapure water was prepared as a solvent using an ultrapure water manufacturing device (RO 15, Hana Science, Korea), and 454.5 g was weighed and prepared. 35 g of pullulan (molecular weight: 100,000 Da, Hayashibara Co., Ltd., Japan), 0.25 g of chitosan (medium molecular weight, 75-85% deacetylated, Sigma-Aldrich, USA), and 0.25 g of ferric chloride (FeCl3, 98%, Junsei, Japan) to be included in the coating solution were weighed and mixed with the ultrapure water to prepare a mixed solution. An aqueous tannic acid solution was prepared by mixing 0.025 g of tannic acid (ACS reagent, Sigma-Aldrich, USA) with 10 g of ultrapure water, and the mixture was mixed with the above-mentioned mixed solution to prepare an eggshell coating composition containing 7 wt% of pullulan based on the total weight of the coating composition. In the above-mentioned eggshell coating composition, tannic acid, chitosan, and ferric chloride were added in amounts of 0.07 part by weight, 0.7 part by weight, and 0.7 part by weight, respectively, per 100 parts by weight of pullulan.

[0069] Egg Coating

[0070] Thirty eggs laid on the same day were washed and prepared, and coating was performed using a spray coater (FUJI SPRAY ® Semi-PRO2, FIJI SPRAY, CANADA). Spray coating was performed by applying the coating solution to the entire surface of the eggshell twice for 5 seconds while maintaining a distance of approximately 10 cm between the egg and the spray nozzle. The coated eggs were placed on a stand to prevent movement and dried twice for 60 seconds using a food dehydrator (OCP-UD660S, OCOO Inc., China) preheated to 75°C. The eggs were then turned over and dried twice for 60 seconds.

[0071]

[0072] (Example 2)

[0073] The same procedure as in Example 1 was followed, except that the eggshell coating composition was prepared so that pullulan was 5 wt% based on the total weight of the coating composition.

[0074]

[0075] (Example 3)

[0076] The same procedure as in Example 1 was followed, except that the eggshell coating composition was prepared so that pullulan was 3 wt% based on the total weight of the coating composition.

[0077]

[0078] (Example 4)

[0079] The same procedure as in Example 1 was followed, except that the eggshell coating composition was prepared by including 0.25 parts by weight of tannic acid (ACS reagent, Sigma-Aldrich, USA) per 100 parts by weight of pullulan.

[0080]

[0081] (Example 5)

[0082] <Manufacturing of coating solution>

[0083] The coating composition of Example 1 was prepared as a first coating agent using a coating liquid, 450 g of ultrapure water was prepared as a solvent using an ultrapure water manufacturing device (RO 15, Hana Science, Korea), and 50 g of gum arabic was prepared as an anionic polysaccharide polymer and mixed with ultrapure water to prepare an anionic polysaccharide polymer solution as a second coating agent.

[0084] Egg Coating

[0085] Thirty eggs laid on the same day were washed and prepared, and coating was performed using a spray coater (FUJI SPRAY ® Semi-PRO2, FIJI SPRAY, CANADA). For spray coating, the first coating agent was applied to the entire eggshell surface twice for 5 seconds while maintaining a distance of approximately 10 cm between the egg and the spray nozzle. Then, the second coating agent was applied to the entire eggshell surface twice for 5 seconds. The eggs were dried at room temperature for 5 minutes, and the first and second coating agents were repeatedly applied using the above method. The coated eggs were placed on a stand so as not to move and dried twice for 60 seconds using a food dehydrator (OCP-UD660S, OCOO Inc., China) preheated to 75°C. The eggs were turned over and dried twice for 60 seconds.

[0086]

[0087] (Comparative Example 1)

[0088] The same procedure as Example 1 was followed except that pullulan was not included.

[0089]

[0090] (Comparative Example 2)

[0091] 30 uncoated eggs were prepared.

[0092]

[0093] (Experimental example)

[0094] The mass change of the eggs corresponding to Examples 1 to 5 and Comparative Examples 1 to 2 was observed for 8 weeks, and the normalized mass of the eggs was calculated using the following equations 1 and 2.

[0095] Equation 1

[0096] Normalized mass change (%) of uncoated eggs = (mass of eggs after n weeks / mass measured after egg purchase) x 100

[0097] Equation 2

[0098] Mass change of coated eggs (%) = (mass of eggs after n weeks / mass measured after coating) x 100

[0099] <Experimental Results> Mass Change (%) Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Week 100 % 100 % 99.4 % 100 % 100 % 99.1 % 98.2 % Week 2 99.4 % 99.0 % 98.2 % 99.2 % 99.8 % 95.4 % 94.1 % Week 3 98.3 % 97.8 % 96.8 % 98.1 % 98.7 % 91.9 % 91.3 % Week 4 96.7 % 95.5 % 94.2 % 95.9 % 97.7 % 89.9 % 89.6 % Week 5 95.9 % 94.1 % 92.4 % 94.8 % 96.9 % 88.8 % 88.2 % Week 6 93.8 % 93.2 %91.1%93.6%95.8%87.9%86.7%Week 792.6%91.6%89.2%92.4%94.6%86.1%85.8%Week 891.7%90.1%88.3%91.0%93.7%84.2%83.1%

[0100] As a result of the experiment, Example 5, manufactured by alternately laminating the first and second coating layers, showed the smallest mass change rate of the eggs over 8 weeks. Example 1 (pullulan 7 wt%) and Example 2 (pullulan 5%) showed similar values ​​of final mass changes of 8.3% and 9.9%, respectively, and the decreasing trends also showed similar values. Example 3 (pullulan 3 wt%) showed a large difference of 11.7% in mass loss compared to Examples 1 and 2 due to its low pullulan content. Comparative Example 1, which did not include pullulan, showed a mass loss similar to that of Comparative Example 2, which did not perform coating.

Claims

1. An eggshell coating composition comprising a cationic polysaccharide polymer, pullulan, a polyphenol compound, and a polyvalent metal salt.

2. In paragraph 1, An eggshell coating composition wherein the cationic polysaccharide polymer is chitosan or chitin.

3. In paragraph 1, An eggshell coating composition wherein the polyphenol compound is a tannin compound.

4. In paragraph 3, An eggshell coating composition, wherein the tannin compound is at least one selected from the group consisting of tannic acid (TA), gallic acid, theaflavin-3-gallate, epigallocatechin gallate, and epicatechin gallate.

5. In paragraph 1, An eggshell coating composition, wherein the metal of the above multivalent metal salt includes a transition metal.

6. In paragraph 5, An eggshell coating composition, wherein the above transition metal salt is one or a mixture of two or more selected from the group consisting of iron gluconate, ferrous fumarate, iron lactate, ferrous sulfate, iron citrate, ammonium ferric citrate, iron phosphate, ferric pyrophosphate, sodium ferric pyrophosphate, copper gluconate, copper sulfate, zinc acetate, zinc chloride, zinc gluconate, zinc oxide, zinc carbonate, zinc sulfate, chromium chloride, and ammonium molybdate.

7. In paragraph 1, An eggshell coating composition further comprising water as a solvent.

8. In paragraph 1, An eggshell coating composition comprising pullulan in an amount of 3 wt% or more based on the total weight of the composition.

9. In paragraph 1, An eggshell coating composition comprising the polyphenol compound:fullan in a weight ratio of 1:800 to 1:2000.

10. In paragraph 1, The above eggshell coating composition comprises the polyphenol compound: polyvalent metal salt in a weight ratio of 1:5 to 1:

20.

11. In paragraph 1, The above eggshell coating composition comprises the pullulan: cationic polysaccharide in a weight ratio of 100:0.1 to 100:

5.

12. A step of preparing a coating solution comprising an eggshell coating composition selected from any one of the first to eleventh clauses; and a step of spraying or dipping the coating solution onto the eggshell and then drying it. An eggshell coating method comprising a unit process.

13. In paragraph 12, An eggshell coating method wherein the spray is sprayed through a plurality of nozzles in the upper or lower direction of the eggshell to coat the eggshell.

14. In paragraph 12, The above drying is a method for coating eggshells, wherein the drying is performed at 50 to 100°C.

15. In paragraph 12, A step of coating the surface of the eggshell coated by the above unit process with a solution containing an anionic polysaccharide; and A step of performing the above unit process on an eggshell coated with the above anionic polysaccharide polymer; A method for coating an eggshell, further comprising:

16. An egg comprising a coating layer comprising a cationic polysaccharide polymer, pullulan, a polyphenol compound, and a polyvalent metal salt.

17. In paragraph 16, An egg in which the coating layer is formed by alternately laminating the first coating layer, which is a complex of the cationic polysaccharide polymer, pullulan, a polyphenol compound, and a polyvalent metal salt, and the second coating layer, which is a complex of the cationic polysaccharide polymer and a polyvalent metal salt, as unit coating layers, and which is positioned on the first coating layer.

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