Fresh-keeping method for golden preserved eggs

Abstract

The invention discloses a preservation method of golden preserved eggs, and belongs to the technical field of food preservation. The preservation method of the golden preserved eggs specifically comprises the following steps: pre-treating the golden preserved eggs, feeding the pre-treated golden preserved eggs into light pulse equipment for sterilization treatment, then carrying out vacuum packaging, and finally storing the packaged golden preserved eggs at a proper temperature. By adopting the method, the quality guarantee period of the golden preserved eggs can be effectively prolonged to about 270-300 days, the good sensory quality of the golden preserved eggs is kept, mildewing, browning and peculiar smell are avoided, meanwhile, nutritional ingredients are effectively reserved and are not obviously changed, a new technical strategy is provided for preservation of the golden preserved eggs, and the method has wide application prospects and huge economic benefits.

Description

Technical Field

[0001] The invention relates to a method for preserving golden preserved eggs, belonging to the technical field of food preservation. Background Art

[0002] Golden preserved eggs refer to preserved eggs with golden yellow, runny yolk and transparent or light translucent egg white. The yolk and egg white of golden preserved eggs are distinct, and the yolk is golden yellow, runny and soft. The general cooking method is to wrap the egg with mud. As a traditional egg product with unique characteristics, the golden preserved egg is very popular among consumers for its unique flavor, color and taste. However, due to the unique production process of golden preserved eggs, the ability to seal the holes on the eggshell surface is relatively weak. For example, Chinese patent application 201310698812.3 discloses a method for producing golden preserved eggs, which has the following shortcomings: during storage, the moisture inside the preserved eggs is very easy to dissipate, which, on the one hand, causes the golden preserved eggs to lose weight seriously, the egg white turns brown, the hardness increases, the yolk turns black, and the yolk becomes runny and coagulated, resulting in a sharp decline in the quality of the preserved eggs; on the other hand, the lost moisture accumulates in the mud and sawdust auxiliary materials on the surface of the preserved eggs, which easily causes mold to grow on the surface of the preserved eggs. Since the quality of golden preserved eggs is extremely sensitive to temperature, the increase in temperature will cause the color of the golden preserved egg protein to darken, the yolk to become runny and coagulated, and the quality to drop sharply, so it is impossible to use traditional thermal sterilization methods to sterilize the golden preserved eggs. At present, the shelf life of golden preserved eggs is relatively short, usually only about three months, which greatly limits the market promotion and economic benefits of golden preserved eggs.

[0003] At present, the preservation methods of golden preserved eggs mainly include refrigeration, drying and fumigation. These methods have achieved certain results in extending the shelf life of golden preserved eggs, but they also have the following limitations: Although the refrigeration method can effectively inhibit the growth and reproduction of microorganisms, the low temperature environment will solidify the yolk, affecting the taste and flavor of the golden preserved eggs, and the refrigeration equipment is expensive and consumes a lot of energy. Although the drying method can reduce the moisture content of golden preserved eggs and inhibit the growth of microorganisms, the golden preserved eggs lose a lot of moisture during the drying process, resulting in a large loss of quality of the golden preserved eggs, shrinkage of the egg white, and increased hardness, which seriously affects the taste and flavor of the golden preserved eggs. Although the fumigation method can kill the microorganisms on the surface of the golden preserved eggs, the fumigant residue is harmful to human health, and the fumigation process is complicated and inconvenient to operate. In the subsequent storage process, due to the loss of moisture from the inside of the preserved eggs, the surface of the preserved eggs is still prone to mold, and the shelf life of the product cannot be effectively controlled.

[0004] In order to overcome the limitations of existing preservation methods, effectively extend the shelf life of golden preserved eggs, maintain the taste and flavor of golden preserved eggs within the shelf life, while reducing costs and improving economic benefits, it is urgently necessary to develop a new golden preserved egg preservation technology. Summary of the invention

[0005] In order to solve the problems of short shelf life of golden preserved eggs, rapid weight loss during storage, easy mold growth on the surface of golden preserved eggs, browning and hardening of egg white, blackening of egg yolk, and runny and coagulated egg yolk, the present invention provides a method for preserving golden preserved eggs; the method uses freshly prepared golden preserved eggs as raw materials, firstly adopts pretreatment under certain conditions to achieve pre-balance of water content in the preserved eggs, then adopts light pulse cold sterilization technology to sterilize the golden preserved eggs, effectively kills microorganisms on the surface of the golden preserved eggs, and then adopts vacuum packaging technology to remove oxygen inside the packaging, further inhibits the growth and reproduction of microorganisms and water loss, thereby effectively maintaining the quality of golden preserved eggs and extending the shelf life of golden preserved eggs.

[0006] The purpose of the present invention is to provide a golden preserved egg preservation method, which can significantly extend the shelf life of the golden preserved eggs, effectively maintain the taste and flavor of the golden preserved eggs during the shelf life, while reducing the processing and storage costs and improving the economic benefits.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preserving golden preserved eggs, comprising the following steps:

[0009] (1) Selecting golden preserved eggs freshly prepared by the mud wrapping process and without surface damage, placing them at 15-25° C. for 8-12 days for pre-equilibration, and the weight loss rate of the golden preserved eggs is 3%-8%;

[0010] (2) Place the golden preserved egg treated in step (1) in a light pulse device for light pulse irradiation. The power of the light pulse is 2 J / cm 2 ~10J / cm 2 , frequency: 1Hz~5Hz, place the golden preserved egg on the placement hole and irradiate it. After irradiating one side, rotate the egg 180 degrees along the long axis and continue irradiating. The irradiation time for each side is: 5s~180s;

[0011] (3) vacuum-packing the preserved eggs after light pulse sterilization in step (2) to a vacuum degree of -0.08 MPa to -0.09 MPa; and then storing them at 4°C to 30°C.

[0012] In one embodiment of the present invention, the storage condition in step (1) is 20-25° C. for 8-10 days; and the weight loss rate of the golden preserved eggs is 4%-8%.

[0013] In one embodiment of the present invention, the storage condition in step (1) is 25° C. for 8 days; the weight loss rate of the golden preserved egg is 5.2%.

[0014] In one embodiment of the present invention, the light pulse irradiation in step (2) is specifically to install a pulse light sterilization device 20cm to 30cm above the surface of the preserved egg sample; an excitation current is applied to make the pulse light lamp work to generate pulse light, and a single pulse lasts for 0.2s.

[0015] In one embodiment of the present invention, the power of the light pulse in step (2) is: 2 J / cm 2 ~4J / cm 2 , frequency: 2Hz~5Hz; irradiation time per side: 30s~180s.

[0016] In one embodiment of the present invention, the power of the light pulse in step (2) is: 2 J / cm 2 , frequency: 5Hz; irradiation time for each side is 180s.

[0017] In one embodiment of the present invention, the vacuum degree in step (3) is -0.09 MPa.

[0018] In one embodiment of the present invention, the storage temperature in step (3) is 4 to 25°C; more preferably 4 to 15°C.

[0019] In one embodiment of the present invention, the storage temperature in step (3) is 4°C.

[0020] In one embodiment of the present invention, the storage time in step (3) is 270 to 300 days.

[0021] Another object of the present invention is to provide an application of the above-mentioned method in the storage process of preserved eggs.

[0022] Beneficial effects:

[0023] Compared with the prior art, the golden preserved egg preservation method of the present invention has the following advantages:

[0024] (1) Effectively extend the shelf life of golden preserved eggs: Light pulse sterilization irradiation can kill microorganisms on the surface of golden preserved eggs, preventing them from getting moldy or deteriorating during storage. Vacuum packaging can prevent moisture loss inside the golden preserved eggs and inhibit the growth and reproduction of microorganisms, thereby effectively extending the shelf life of golden preserved eggs to about 270 to 300 days.

[0025] (2) Maintaining the taste and flavor of golden preserved eggs: Light pulse irradiation sterilization is a cold sterilization technology, and vacuum packaging is a physical storage method, neither of which will have an adverse effect on the taste and flavor of golden preserved eggs;

[0026] (3) Easy operation and low cost: The light pulse sterilization combined with vacuum preservation method requires simple equipment, is easy to operate, low cost, and easy to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The actual effect diagram of the golden preserved eggs of the embodiment and the comparative example after being stored for 270 days;

[0028] Figure 2 The present invention is a process flow chart of the method for preserving golden preserved eggs. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention are described below. It should be emphasized that the following embodiments are for better explanation of the present invention and are not intended to limit the present invention. The methods described are conventional methods unless otherwise specified.

[0030] Test method:

[0031] Total colony count: Determined according to GB 4789.2 Food Hygiene Microbiology Test Total colony count.

[0032] Weight loss rate: The mass loss rate refers to the degree of water loss of preserved eggs during storage. Select 5 preserved eggs, weigh them using an analytical balance (0.0001g), and record the weight of each preserved egg at the beginning of storage and after a certain period of storage. Calculate according to the mass loss rate calculation formula.

[0033] pH: Refer to the determination of the pH value of preserved eggs in the analytical method of GB / T5009.47-2003 Hygienic Standards for Eggs and Egg Products, and make slight modifications. Take 5 preserved eggs, wash them, peel them, and separate them into egg white and egg yolk. Add distilled water to the egg white and egg yolk in a ratio of 2:1, and place them in a beater to beat them. Take 15g of egg white and egg yolk slurry and place them in a beaker respectively. Add 150mL of water, homogenize them with a homogenizer, and filter them with gauze. Take 50mL of the filtrate to measure the pH value with a pH meter, and measure it in parallel 3 times.

[0034] Gel texture: Take a 1cm×1cm×1cm cube from the egg white of the preserved egg, place it in the center of the base of the physical property tester, use the compression mode to measure the gel strength, and use the hardness value obtained in the test to express it. The hardness value refers to the force of the sample felt by the probe when the probe compresses the sample to a certain deformation, which is the maximum peak value of one compression. The probe model is: TA4 / 1000 (diameter 38.1mm), and the measurement parameters are: pre-measurement rate: 1.0m / s, test rate 0.5m / s, return rate 0.5m / s, target distance 6mm, trigger point load 10g, and number of cycles 1. The hardness value is obtained from the instrument supporting software.

[0035] Sensory evaluation: With reference to the sensory evaluation standards of preserved eggs in GB9694-2014, 8 trained food professionals conducted the evaluation, which was divided into 5 categories: color, appearance, texture, smell and taste, with a maximum score of 20 points for each category and a total score of 100 points.

[0036] The method for making fresh golden preserved eggs by the mud wrapping method of the present invention is prepared by referring to a method for producing golden preserved eggs disclosed in Chinese patent CN201910987771.7.

[0037] Example 1

[0038] A method for preserving golden preserved eggs, comprising the following steps:

[0039] (1) Pretreatment of Golden Preserved Eggs

[0040] Select freshly prepared golden preserved eggs without cracks by mud wrapping, place them in 20℃ environment for 10 days, and the weight loss rate is 4.0%;

[0041] (2) Light pulse sterilization

[0042] The golden preserved eggs pretreated in step (1) are sterilized by using a light pulse, and the power of the light pulse is 4 J / cm 2 , frequency is 2Hz, place the golden preserved egg on the placement hole and irradiate it. After irradiating one side, rotate the egg 180 degrees along the long axis and continue irradiating. The irradiation time for each side is 30s;

[0043] (3) Vacuum packaging and storage

[0044] The golden preserved eggs sterilized in step (2) are placed in a vacuum packaging bag with a vacuum degree of -0.085 MPa, and then stored at 15°C.

[0045] Example 2

[0046] A method for preserving golden preserved eggs, comprising the following steps:

[0047] (1) Pretreatment of Golden Preserved Eggs

[0048] Select freshly prepared golden preserved eggs without cracks by mud wrapping, place them in 15℃ environment for 8 days, and the weight loss rate is 3.0%;

[0049] (2) Light pulse sterilization

[0050] The golden preserved eggs pretreated in step (1) are sterilized by light pulses, the power of the light pulses is 2 J / cm2, and the frequency is 1 Hz; the golden preserved eggs are placed on the placement hole for irradiation, and after irradiating one side, the eggs are rotated 180 degrees along the long axis and irradiated again, and the irradiation time for each side is 120 s;

[0051] (3) Vacuum packaging

[0052] The golden preserved eggs sterilized in step (2) are placed in a vacuum packaging bag with a vacuum degree of -0.085 MPa, and then stored at 25°C.

[0053] Example 3

[0054] A method for preserving golden preserved eggs, comprising the following steps:

[0055] (1) Pretreatment of Golden Preserved Eggs

[0056] Select freshly prepared golden preserved eggs without cracks by mud wrapping, place them in 15℃ environment for 12 days, and the weight loss rate is 3.8%;

[0057] (2) Light pulse sterilization

[0058] The golden preserved eggs pretreated in step (1) are sterilized by using a light pulse, and the power of the light pulse is 5 J / cm 2 , frequency is 1Hz; place the golden preserved egg on the placement hole and irradiate it. After irradiating one side, rotate the egg 180 degrees along the long axis and continue irradiating. The irradiation time for each side is 5s;

[0059] (3) Vacuum packaging

[0060] The golden preserved eggs sterilized in step (2) are placed in a vacuum packaging bag with a vacuum degree of -0.08 MPa, and then stored at 30°C.

[0061] Example 4

[0062] A method for preserving golden preserved eggs, comprising the following steps:

[0063] (1) Pretreatment of Golden Preserved Eggs

[0064] Select freshly prepared golden preserved eggs without cracks by mud wrapping, place them in 25℃ environment for 8 days, and the weight loss rate is 5.2%;

[0065] (2) Light pulse sterilization

[0066] The golden preserved eggs pretreated in step (1) are sterilized by light pulses, the power of the light pulses is 2 J / cm2, and the frequency is 5 Hz; the golden preserved eggs are placed on the placement hole for irradiation, and after irradiating one side, the eggs are rotated 180 degrees along the long axis and irradiated again, and the irradiation time for each side is 180 seconds;

[0067] (3) Vacuum packaging

[0068] The golden preserved eggs sterilized in step (2) are placed in a vacuum packaging bag with a vacuum degree of -0.09 MPa and then stored at 4°C.

[0069] Example 5

[0070] A method for preserving golden preserved eggs, comprising the following steps:

[0071] (1) Pretreatment of Golden Preserved Eggs

[0072] Select freshly prepared golden preserved eggs without cracks by mud wrapping, place them in 25℃ environment for 12 days, and the weight loss rate is 8.0%;

[0073] (2) Light pulse sterilization

[0074] The golden preserved eggs pretreated in step (1) are sterilized by using a light pulse, the power of which is 10 J / cm 2 , frequency is 5Hz; place the golden preserved egg on the placement hole and irradiate it. After irradiating one side, rotate the egg 180 degrees along the long axis and continue irradiating. The irradiation time for each side is 5s;

[0075] (3) Vacuum packaging

[0076] The golden preserved eggs sterilized in step (2) are placed in a vacuum packaging bag with a vacuum degree of -0.08 MPa, and then stored at 20°C.

[0077] Example 6

[0078] A method for preserving golden preserved eggs, comprising the following steps:

[0079] (1) Pretreatment of Golden Preserved Eggs

[0080] Select freshly prepared golden preserved eggs without cracks by mud wrapping, place them in 25℃ environment for 10 days, and the weight loss rate is 6.8%;

[0081] (2) Light pulse sterilization

[0082] The golden preserved eggs pretreated in step (1) are sterilized by using a light pulse, and the power of the light pulse is 5 J / cm 2 , frequency is 2Hz; place the golden preserved egg on the placement hole and irradiate it. After irradiating one side, rotate the egg 180 degrees along the long axis and continue irradiating. The irradiation time for each side is 60s;

[0083] (3) Vacuum packaging

[0084] The golden preserved eggs sterilized in step (2) are placed in a vacuum packaging bag with a vacuum degree of -0.09 MPa, and then stored at 15°C.

[0085] Comparative Example 1

[0086] The light pulse sterilization treatment in step (2) of Example 1 was omitted, and the rest was the same as Example 1.

[0087] Comparative Example 2

[0088] The vacuum packaging in step (3) of Example 1 was omitted, and the rest was the same as in Example 1.

[0089] Comparative Example 3

[0090] The light pulse sterilization power in step (2) of Example 1 was set to 1 J / cm 2 , the rest are the same as in Example 1.

[0091] Comparative Example 4

[0092] The light pulse sterilization power in step (2) of Example 1 was set to 15 J / cm 2 , the rest are the same as in Example 1.

[0093] Comparative Example 5

[0094] The light pulse sterilization time for each side in step (2) of Example 1 was set to 3 s, and the rest was consistent with Example 1.

[0095] Comparative Example 6

[0096] The light pulse sterilization time for each side in step (2) of Example 1 was set to 210 s, and the rest was consistent with Example 1.

[0097] Comparative Example 7

[0098] The vacuum degree of the vacuum packaging in step (3) in Example 1 was set to -0.05 MPa, and the rest was consistent with Example 1.

[0099] Comparative Example 8

[0100] The vacuum degree of the vacuum packaging in step (3) in Example 1 was set to -0.095 MPa, and the rest was consistent with Example 1.

[0101] Comparative Example 9

[0102] The storage temperature of step (4) in Example 1 was set to 0°C, and the rest was the same as in Example 1.

[0103] Comparative Example 10

[0104] The storage temperature of step (4) in Example 1 was set to 35° C., and the rest was the same as in Example 1.

[0105] Comparative Example 11

[0106] The pretreatment conditions of step (1) in Example 1 were set to 30° C. for 10 days, and the weight loss rate was measured to be 8.8%. Other conditions were the same as in Example 1.

[0107] Comparative Example 12

[0108] The pretreatment conditions of step (1) in Example 1 were set to 4° C. for 10 days, and the weight loss rate was measured to be 1.2%. Other conditions were consistent with Example 1.

[0109] Comparative Example 13

[0110] The sterilization method in step (2) of Example 1 was changed to ultraviolet sterilization, with each side irradiated for 15 minutes. The irradiation distance between the ultraviolet sterilization lamp and the surface of the preserved egg was 10 cm. Other conditions were the same as in Example 1.

[0111] Comparative Example 14

[0112] The sterilization method in step (2) of Example 1 was changed to microwave sterilization for 2 minutes. The microwave frequency emitted by the microwave generator was 2.45 GHz and the power was 1 KW. Other aspects were consistent with Example 1.

[0113] Results Analysis

[0114] The total colony count, texture, pH, weight loss rate, sensory score, and shelf life of Examples 1-6 and Comparative Examples 1-14 were measured. The test results are shown in Table 1-6:

[0115] Table 1 Total colony count inside golden preserved eggs (unit: CFU / g)

[0116]

[0117]

[0118] As a result, during the storage of golden preserved eggs, as the storage time increases, although the total number of sample colonies generally increases, the total number of colonies in the embodiment increases relatively slowly compared with the comparative example, indicating that pulsed light sterilization combined with vacuum packaging can effectively inhibit the growth of microorganisms during storage. When the vacuum degree is low, such as comparative example 7, the total number of sample colonies grows rapidly during storage, and the total number of colonies increases to 30,000 CFU / g on the 270th day. This may be because the vacuum degree is too low, and some air is retained in the packaging, which cannot effectively inhibit the growth of microorganisms. However, due to the high vacuum degree in comparative example 8, the moisture in the preserved egg is lost outward during the vacuuming process, and it gathers in the preserved egg air chamber. Although the high vacuum degree can effectively inhibit the growth of microorganisms, it will cause the quality of the preserved egg to deteriorate. Therefore, the vacuum degree should not be too high or too low during the vacuum preservation of preserved eggs. The total number of colonies in comparative example 10 exceeded 100,000 CFU / g at 270 days, showing that the reproduction of microorganisms is out of control, indicating that the storage temperature of preserved eggs should not be too high. Comparative Examples 13 and 14 used different sterilization methods. The total colony count inside the golden preserved eggs increased faster than that by light pulse sterilization. After 270 days, it increased to 50,000 and 30,000 CFU / g respectively. The sterilization effect was significantly worse than that by light pulse sterilization.

[0119] Table 2 Changes in pH value of golden preserved eggs

[0120]

[0121] The pH value of golden preserved eggs is an important indicator of the quality of preserved eggs. From the results in Table 2, it can be seen that the pH value of preserved eggs in each embodiment decreases slowly, while the pH value of comparative example 1, which has not been sterilized by light pulse, decreases rapidly, and drops below the national standard requirement of 9.0 in about 130 days. This may be because the surface of the preserved eggs has not been sterilized by light pulse, and the microorganisms on the surface of the preserved eggs enter the interior of the preserved eggs during storage, resulting in the accelerated growth of microorganisms inside the preserved eggs, which slows down the decrease in the pH value inside the preserved eggs. Comparative example 2 was not vacuum packaged, and the dehydration of the preserved eggs balanced the change in pH value, but due to severe dehydration, the preserved eggs in this comparative example had no edible value after 120 days, and the experiment was stopped. The pH decrease rate of the preserved eggs in comparative examples 13 and 14 was significantly faster than that in the embodiments.

[0122] Table 3 Changes in weight loss rate of golden preserved eggs

[0123]

[0124] As can be seen from the results in Table 3, vacuum packaging has excellent water retention, which greatly reduces the rate of water loss of golden preserved eggs. The weight loss rate of Comparative Example 2, which is not vacuum packaged, is as high as 25.67% in about 120 days, and it has no edible value. The storage temperature of preserved eggs also affects the weight loss rate. In the embodiment, the weight loss rate of preserved eggs is low after 270 days of storage within the storage temperature range of 4-30°C. When the storage temperature is too high (such as Comparative Example 10), the weight loss rate of preserved eggs increases significantly, and when the storage temperature is too low (Comparative Example 9), although the weight loss rate of preserved eggs is extremely low, too low storage temperature will cause the quality of preserved eggs to deteriorate significantly, so the storage temperature of preserved eggs needs to meet a certain range. In addition, the degree of preserving egg pretreatment also affects the weight loss rate of the preserved eggs during storage. For Example 11, the temperature of the pretreatment process is too high and the weight loss rate of the preserved eggs is too large. Although the weight loss rate of the preserved eggs during storage can be reduced, it will cause other qualities of the preserved eggs to deteriorate. For Example 12, the temperature of the pretreatment process is too low, the weight loss rate of the preserved eggs is too low, and the water content of the preserved egg samples is too high, which increases the weight loss rate during storage and affects other qualities of the preserved eggs. Therefore, it is necessary to remove a certain amount of water in the fresh preserved egg samples by controlling the pretreatment conditions to ensure the quality of the preserved egg samples during storage.

[0125] Table 4 Texture changes of golden preserved eggs during storage

[0126]

[0127] As shown in Table 4, with the extension of storage time, the hardness and elasticity of Examples 1 to 6 change in a small range, especially Example 4, which has a relatively small change in hardness and elasticity, indicating that the texture of the golden preserved egg is well maintained when stored at low temperature. Comparative Examples 1 to 14 show a large texture change, among which the hardness of Comparative Example 2 has significantly increased to 521g at 30 days and reached 1013g at 90 days, and the elasticity has also increased from 0.466 to 0.995. This drastic change may be due to the fact that the vacuum packaging was not carried out, and the water loss was fast. After 270 days, due to the serious water loss of the preserved egg, this indicator could no longer be measured. The hardness and elasticity of Comparative Examples 4 and 6 deteriorated quickly, which may be due to excessive light pulse sterilization, causing certain changes in the structure of the preserved egg, thereby causing the quality of the preserved egg to deteriorate. The hardness and elasticity of Comparative Example 13 are slightly higher than those of the embodiment, which may be due to the fact that the ultraviolet sterilization effect is worse than the pulse light sterilization, and the microorganisms on the surface of the preserved egg enter the preserved egg to grow inside the preserved egg, causing water imbalance and changes in the internal structure. The hardness and elasticity of comparative example 14 are significantly higher than those of the embodiment, which may be due to the change in the internal structure of the preserved egg caused by the microwave thermal effect. The above examples show that the combination of light pulse sterilization and vacuum packaging effectively slows down the texture degradation of golden preserved eggs during storage, especially the decline in hardness and elasticity, thereby maintaining the quality of the product and the eating experience.

[0128] Table 5 Changes in sensory evaluation of golden preserved eggs

[0129]

[0130]

[0131] As can be seen from the results in Table 5, the golden preserved eggs initially had a higher sensory quality. As the storage time increased, the sensory scores of the various embodiments gradually decreased, but the extent of the decrease was different. In contrast, the sensory score of the comparative example decreased more significantly. For example, the sensory score of comparative example 1 was only 53 after 270 days of storage, while the sensory score of comparative example 2 had dropped to 43 points at 120 days, indicating that the sensory quality of the preserved egg samples decreased rapidly without light pulse sterilization and vacuum packaging. The sensory score of comparative example 10 was only 49 points after 270 days of storage, indicating that excessively high storage temperatures would accelerate the deterioration of the sensory quality of the samples. The sensory scores of comparative examples 3-6 were lower than those of the embodiments, indicating that it was necessary to control appropriate light pulse power and irradiation time in order to better preserve the quality of the preserved egg samples. After comparative examples 13 and 14 were sterilized by ultraviolet light and microwave respectively, the color of the golden preserved eggs became significantly darker during storage, and the rate of decrease in sensory quality was also significantly faster than that of the embodiments.

[0132] Table 6 Shelf life results of golden preserved eggs

[0133]

[0134] As can be seen from the results in Table 6, the shelf life of Examples 1 to 6 ranges from 270 to 300 days, indicating that the method of the present invention can effectively extend the shelf life of golden preserved eggs. The shelf life of Example 4 reaches 300 days, which may be due to its storage temperature of 4°C. This low temperature condition helps to further extend the shelf life. The shelf life of the comparative examples is generally shorter, among which the shelf life of Comparative Examples 1 and 2 is only 130 days and 90 days, which fully demonstrates that the combination of light pulse sterilization and vacuum packaging can greatly extend the shelf life of golden preserved eggs. The shelf life of Comparative Examples 3, 4, 5, and 6 is shorter than that of the embodiments, which illustrates the importance of selecting appropriate sterilization power and time. Comparative Examples 7 and 8 illustrate the effect of vacuum degree on shelf life. The vacuum degree of vacuum packaging of preserved eggs should not be too low or too high. Comparative Examples 9 and 10 show that the appropriate storage temperature has a significant impact on the shelf life. If the storage temperature is too high, the shelf life will be shortened (Comparative Example 10); while if the storage temperature is too low, although the shelf life can reach 280 days (Comparative Example 9), the quality of the preserved eggs is greatly affected due to storage at 0°C, and the sensory score is significantly lower than that of the embodiment. Comparative Examples 11 and 12 show that the appropriate degree of pretreatment plays an important role in extending the shelf life of golden preserved eggs. Comparative Examples 13 and 14 are 160 days and 180 days, respectively, which are significantly lower than the embodiment, indicating that the effect of ultraviolet and microwave sterilization methods on extending the shelf life of golden preserved eggs is worse than light pulse sterilization.

[0135] And by Figure 1 The results show that after 270 days of storage, the color of the egg white in the examples changed slightly, while the yolk still maintained a good color and runny texture. In Example 3, the yolk showed a small amount of black, but the overall texture remained good. After 270 days of storage, the color and texture of the egg white and yolk of Example 4 did not change much, and the golden preserved egg still had a runny texture.

[0136] In contrast, the egg whites in the comparative examples generally showed obvious browning, lost their golden color, and the yolks partially turned black and showed varying degrees of hydration, resulting in the loss of the runny texture. In particular, Comparative Example 2 lost water seriously during storage, and the yolks of Comparative Example 14 retained their color but were completely hydrated. The yolks of Comparative Examples 1, 3, 4, 5, 7, 10, and 12 all showed a large part of blackening and lost their runny texture. The transparency of the egg whites in Comparative Example 9 was reduced, the texture was significantly deteriorated, and the yolks were partially hydrated. At the beginning of storage, a small amount of black appeared in the yolks of Comparative Example 11. After 270 days of storage, the yolks were partially black and completely solidified.

[0137] It can be seen that the overall quality of the golden preserved eggs in the embodiment is better than that of the comparative example after storage for 270 days, especially in terms of maintaining the color and texture of egg white and yolk. However, the golden preserved eggs in the comparative example generally show obvious browning and texture damage during storage, and lose their edible value.

[0138] The above results indicate that the light pulse sterilization combined with vacuum preservation method of the present invention can effectively control the growth of microorganisms in golden preserved eggs during storage, effectively extend the shelf life of golden preserved eggs, and maintain their good quality, and has significant practical value and broad market application prospects.

[0139] The invention discloses a light pulse vacuum preservation method for golden preserved eggs. After pretreatment, the golden preserved eggs are sent to a light pulse device for sterilization, then vacuum packaged, and finally stored at a suitable temperature. The method can effectively extend the shelf life of the golden preserved eggs to about 270 days, and maintain its good sensory quality, without mildew, browning, and odor. At the same time, the nutrients are effectively retained without significant changes, providing a new technical solution for the preservation of golden preserved eggs, with broad application prospects and huge economic benefits.

[0140] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preserving golden preserved eggs, characterized in that: The method comprises the following steps: (1) Selecting golden preserved eggs freshly prepared by the mud wrapping process and without surface damage, placing them at 15-25° C. for 8-12 days for pre-equilibration, and the weight loss rate of the golden preserved eggs is 3%-8%; (2) Place the golden preserved egg treated in step (1) in a light pulse device for light pulse irradiation. The power of the light pulse is 2 J / cm 2 ~10J / cm 2 , frequency: 1Hz~5Hz, place the golden preserved egg on the placement hole and irradiate it. After irradiating one side, rotate the egg 180 degrees along the long axis and continue irradiating. The irradiation time for each side is: 5s~180s; (3) vacuum-packing the preserved eggs after light pulse sterilization in step (2) to a vacuum degree of -0.08 MPa to -0.09 MPa; and then storing them at 4°C to 30°C.

2. The method according to claim 1, characterized in that The storage condition of step (1) is 20-25° C. for 8-10 days; the weight loss rate of the golden preserved egg is 4%-8%.

3. The method according to claim 1, characterized in that The storage condition of step (1) is 25° C. for 8 days; the weight loss rate of the golden preserved egg is 5.2%.

4. The method according to claim 1, characterized in that The light pulse irradiation in step (2) specifically comprises installing a pulse light sterilization device 20 cm to 30 cm above the surface of the preserved egg sample; exciting current to make the pulse light lamp work to generate pulse light, and a single pulse duration is 0.2 s.

5. The method according to claim 1, characterized in that The power of the light pulse in step (2): 2 J / cm 2 ~4J / cm 2 , frequency: 2Hz~5Hz; irradiation time per side: 30s~180s.

6. The method according to claim 1, characterized in that The power of the light pulse in step (2): 2 J / cm 2 , frequency: 5Hz; irradiation time for each side is 180s.

7. The method according to claim 1, characterized in that The vacuum degree in step (3) is -0.09MPa.

8. The method according to claim 1, characterized in that The storage temperature in step (3) is 4-25°C.

9. The method according to claim 1, characterized in that: The storage time in step (3) is 270 to 300 days.

10. Use of the method according to any one of claims 1 to 9 in the storage process of preserved eggs.

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