Local coating preservation method for eggs

Abstract

The invention discloses a local coating preservation method for eggs. According to the method, 30-100% of the surface of the blunt end of a fresh egg is coated with liquid paraffin, polyvinyl alcohol and other eggshell preservative film materials. According to the method, egg preservation is achieved through local eggshell coating, the weight loss in the storage period is reduced, the process is simple, and the cost is extremely low. According to the prepared locally coated eggs, the quality decline rate is obviously slowed down, and the weight loss is obviously reduced. When the egg is opened, the coating material can be effectively prevented from being in contact with the content of the egg, and the safety is high.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural product preservation methods, in particular to a method for preserving eggs by partial coating. Background Art

[0002] During storage, eggs are susceptible to extreme environmental conditions, microorganisms, and other factors that may cause quality degradation. The more obvious indicators are increased weight loss and decreased Haugh units (HU). The former causes sales losses for egg producers, while the latter significantly affects consumer experience and even leads to food safety risks. Especially in hot seasons, the quality of eggs will significantly deteriorate after being stored at room temperature for 10 days.

[0003] At present, the most ideal technology for preserving eggs is cleaning and coating, that is, selling them as "clean eggs". "Clean eggs" are poultry eggs that have been cleaned, dried, disinfected, coated, and packaged on pallets. The coating materials for eggs have clear usage regulations in the "Healthy Standard for the Use of Food Additives GB2760-2014", and there are many varieties. Most of the related research focuses on the development of coating materials, which are developed in the direction of high safety, ecological protection, and low cost.

[0004] The production of clean eggs requires large equipment investment and high operating energy consumption, so only a few poultry companies use it. According to statistics on circulation and consumption, the proportion of "clean eggs" is very low. At present, most medium and small-scale chicken farms do not process eggs for freshness preservation, but directly store them at room temperature or sell them on the market.

[0005] As fresh agricultural products, eggs are treated to be fresh. Once the storage period is too long, even if the recognized freshness and safety indicators have not decreased significantly, their taste will inevitably be affected. Therefore, the real goal of egg preservation is to reduce the weight loss rate of eggs during the 10-15 days of storage in the hot season, so as to reduce the income loss of breeding enterprises. Summary of the invention

[0006] In view of the fact that the existing egg preservation technology has high requirements on breeding scale and large investment in processing equipment, the purpose of the present invention is to provide an egg coating preservation method to reduce the weight loss rate of eggs in high temperature seasons and effectively maintain their quality.

[0007] In order to achieve the purpose of the present invention, the inventor provides the following technical solution: a method for preserving eggs by coating them locally, comprising the following steps:

[0008] (1) Clean the eggshells of fresh eggs and eggs with thin or damaged shells, remove surface dirt, and stack qualified eggs on egg trays with the blunt end facing upwards;

[0009] (2) coating the egg shell with egg coating material; the coating material covers 30-100% of the blunt end of the egg, that is, the shell surface from the large end of the egg to the transverse cross-section; after coating, the egg is still placed with the blunt end facing upward.

[0010] (3) During the egg storage period, the egg tray needs to be kept still to ensure the safety of the eggs.

[0011] Specifically, the fresh eggs in step (1) are eggs laid between 0 and 72 hours, and the volume of the egg air chamber is inversely proportional to the preservation effect.

[0012] Specifically, in step (2), the coating material is liquid paraffin, polyvinyl alcohol, chitosan and other commercial materials, or a self-prepared egg coating material that is non-toxic and airtight after film formation.

[0013] Specifically, the coating treatment in step (2) includes wiping, spraying, brushing, and film pasting.

[0014] Specifically, when the coating area in step (2) is 40 to 80% of the blunt-end surface, the preservation effect is optimal.

[0015] Compared with the prior art, the present invention has the following technical effects:

[0016] (1) For small and medium-sized chicken farms without processing facilities and low-temperature storage conditions, the present invention provides a preservation technology solution that can effectively slow down the decline in egg quality and weight loss, without the need for complex equipment and processing materials.

[0017] (2) Compared with "clean eggs", the present invention can reduce the amount of coating materials used by 50-70%, thereby reducing costs. Even if the treated eggs are stored in an extremely high temperature environment for 10 days, the weight loss can be reduced by more than 1%; the important index value of the freshness of the egg content does not decrease significantly.

[0018] (3) Compared with the "clean eggs" that are fully covered with coating materials, the eggshell coating in the technology of the present invention is only on the blunt end of the egg. When opening the egg, the egg contents can be effectively prevented from contacting with the coating material, and food safety is effectively guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the coating area (grey) of the test egg of the present invention. DETAILED DESCRIPTION

[0020] The present invention is described in more detail below with reference to the following examples. The implementation of the present invention is not limited to the following examples.

[0021] Example 1

[0022] (1) Collect a batch of eggs laid by Hy-Line Brown commercial laying hens (24 weeks old) on the same day, discard the defective eggs, and select eggs with uniform weight and consistent eggshell quality as test eggs. Wipe the surface of the test eggs clean with a dry cloth to remove obvious dirt, and arrange them on a paper egg tray. The test is divided into 3 groups, each with 180 eggs, and each egg is numbered.

[0023] (2) Using commercially available food-grade liquid paraffin as the coating material, the eggs in the test group were coated one by one, with the coating being uniform and of consistent thickness. The control group was not coated, the blunt end surface of the eggs in treatment group 1 was 100% coated, and the surface of the eggs in treatment group 2 was fully coated. Each group was weighed and recorded one by one, with the large end facing upward.

[0024] (3) All test eggs were stored in a room at a temperature of 32°C to 35°C and a relative humidity of 55% to 60%. The eggs were weighed at 10 and 20 days of age, and the Haugh unit value of 20 eggs in each group was measured.

[0025] The test results of the eggs in this example are shown in Table 1:

[0026] Table 1

[0027]

[0028] Note: Data in the same row with different letters indicate significant differences between groups (p<0.05).

[0029] As can be seen from the data in Table 1, the test results show that: [1] After 10 and 20 days of storage under high temperature conditions, the weight loss rate of eggs in the control group > treatment group 1 > treatment group 2; the freshness of eggs measured in Haugh units was control group < treatment group 1 < treatment group 2; there were significant differences between the groups (p<0.05). [2] After 10 days of storage, the weight loss rate of eggs in treatment group 1 was 1.7 percentage points lower than that in the control group. The Haugh unit value decreased compared with that before storage, but the difference between the groups was not significant (p>0.05), and there was no significant difference between the two treatment groups during the same period (p>0.05). [3] After 20 days of storage, the water loss rate of eggs in treatment group 1 was 2.6 percentage points lower than that in the control group; the Haugh unit was still above 70, close to the lower limit of the national quality requirements for special-grade eggs.

[0030] Test conclusion: The technology of the present invention can significantly reduce the water loss rate of eggs and the rate of quality decline of eggs when eggs are stored for 10 and 20 days under extreme high temperature conditions, and has good economic performance. The overall preservation effect is not as good as that of the whole egg coating treatment group.

[0031] Example 2

[0032] (1) Collect a batch of eggs laid by Hy-Line Brown commercial laying hens (55 weeks old) on the same day, discard the defective eggs, and select eggs with uniform weight and consistent eggshell quality as test eggs. Wipe the surface of the test eggs clean with a dry cloth to remove obvious dirt, and arrange them on a paper egg tray.

[0033] (2) The experiment was divided into 4 groups, each with 80 eggs. Each egg was numbered. The eggs in the control group were not coated. The eggs in treatment groups 1 and 2 were coated with 30% and 90% of the blunt end area, respectively. The eggshell surface of treatment group 4 was coated. After the coating treatment, the eggs were stored with the blunt end facing up at a temperature of 28℃ to 30℃ and a relative humidity of 60-65%. The storage period was 15 days.

[0034] like Figure 1 Schematic diagram of the coating area (grey) of the test egg shown, the dotted line is the short diameter of the egg;

[0035] (3) The coating material is a composite film-forming product made of polyvinyl alcohol, chitosan, stearic acid, etc., which meets the national food hygiene and safety standards. The initial weight of fresh test eggs was 63.4±2.5 grams, and there was no significant difference in the weight of eggs in each group. After 15 days, the weight of 60 eggs in each group was measured, and the Haugh units of 20 eggs were measured.

[0036] The test results of the eggs in this example are shown in Table 2:

[0037] Table 2

[0038] project Control group Treatment 1 group Treatment 2 groups Treatment 3 groups Weight loss g 1.51±0.25a 0.93±0.22b 0.84±0.24c 0.26±0.15d Weight loss rate % 2.37±0.40a 1.50±0.35b 1.35±0.33c 0.40±0.15d Haff Unit HU 62.9±7.9a 74.8±4.9b 79.7±4.3c 84.1±7.6d

[0039] Note: Data in the same row with different letters indicate significant differences between groups (p<0.05).

[0040] As shown in Table 2, the test results show that: [1] After 15 days of storage at room temperature, the egg weight loss and weight loss rate Haugh unit among the treatment groups were significantly different (p<0.05), and the preservation effect was treatment group 3>treatment group 2>treatment group 1. [2] Compared with the control group, treatment group 1 and treatment group 2 reduced the egg weight loss rate by 37% and 43%, respectively, both with significant effects. The egg Haugh unit of the two treatment groups was higher than 75, meeting the quality requirements of premium eggs.

[0041] Test conclusion: By adopting the technology of the present invention, eggs can be stored at room temperature of 28℃ to 30℃ for 15 days, which can significantly reduce the water loss rate of eggs and significantly slow down the rate of decline in egg quality, and has good economic performance.

Claims

1. A method for preserving eggs by coating them locally, characterized in that: The steps include: (1) Clean the eggshells of fresh eggs and eggs with thin or damaged shells, remove surface dirt, and stack qualified eggs on egg trays with the blunt end facing upwards; (2) coating the egg shell with egg coating material; the coating material covers 30-100% of the blunt end of the egg, that is, the shell surface from the large end of the egg to the transverse cross-section; after coating, the egg is still placed with the blunt end facing upward. (3) During the egg storage period, the egg tray needs to be kept still to ensure the safety of the eggs.

2. The method for preserving eggs by partial coating as claimed in claim 1, characterized in that: The fresh eggs in step (1) are eggs laid between 0 and 72 hours, and the volume of the egg air chamber is inversely proportional to the preservation effect.

3. The method for preserving eggs by partial coating as claimed in claim 1, characterized in that: In the step (2), the coating material is liquid paraffin, polyvinyl alcohol, chitosan and other commercial materials, or a self-prepared egg coating material that is non-toxic and airtight after film formation.

4. The method for preserving eggs by partial coating as claimed in claim 1, characterized in that: The coating treatment in step (2) includes wiping, spraying, brushing and film pasting.

5. The method for preserving eggs by partial coating as claimed in claim 1, characterized in that: When the coating area in step (2) is 40 to 80% of the blunt-end surface, the preservation effect is optimal.

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