Selenium-rich runny yolk salted egg and preparation method and application thereof

Abstract

This invention relates to a selenium-enriched soft-boiled marinated egg, its preparation method, and its application, belonging to the field of food processing technology. The method includes raw material pretreatment, primary pre-cooking, secondary steaming, braising broth preparation, low-temperature marinating, sterilization, and other processing steps. Through a combined process of "medium-high temperature pre-cooking – precise steaming – rapid cooling," the soft-boil rate of the egg is consistently maintained above 80%. The resulting selenium-enriched soft-boiled marinated egg has a stable selenium content, is safe and healthy, and has a semi-liquid, soft-boiled yolk with a rich marinade aroma.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a selenium-enriched soft-boiled marinated egg, its preparation method, and its application. Background Technology

[0002] As a traditional egg product with a long history in my country, braised eggs are a popular snack and side dish due to their rich aroma, firm texture, and convenient consumption. Among them, soft-boiled braised eggs, with their semi-liquid yolks, offer a smoother and more tender flavor compared to fully cooked braised eggs, and have become increasingly popular in the market in recent years, representing one of the upgrade directions for the braised egg category. Selenium, an essential trace element for the human body, plays a vital role in enhancing immunity, scavenging free radicals, anti-oxidation, and protecting cardiovascular health. It is an indispensable nutrient for maintaining normal physiological activities, making the research and promotion of selenium-enriched foods a hot topic in the food industry.

[0003] Selenium-enriched egg products, as an important branch of selenium-enriched foods, are currently mainly prepared by feeding selenium-enriched feed to poultry farmers to achieve selenium enrichment. Selenium-enriched soft-boiled marinated eggs combine the soft-boiled texture with selenium nutrition, satisfying consumers' pursuit of flavor while meeting healthy dietary needs, thus possessing huge market potential. However, the preparation of this product faces two technical bottlenecks: on the one hand, precise control of the soft-boiled state requires stringent processing techniques; traditional heating methods can easily result in over-coagulation of the yolk, losing its soft-boiled characteristic, or insufficient coagulation, leading to food safety risks; on the other hand, selenium is easily lost during the marinating process due to high temperatures and changes in acidity and alkalinity, resulting in reduced bioavailability.

[0004] Therefore, developing a method for preparing selenium-enriched soft-boiled marinated eggs with precise and controllable selenium content, stable soft-boil state, and safety and health, and solving the technical problem of balancing sensory appeal and nutrition, has significant market value and application prospects. Summary of the Invention

[0005] To address the challenges in simultaneously maintaining stable selenium levels, controlling the runny yolk consistency, achieving optimal marinating flavor, and ensuring ready-to-eat safety during the processing of selenium-enriched egg products in existing technologies, this invention provides a selenium-enriched runny-yolk marinated egg, its preparation method, and its applications. The method includes raw material pretreatment, primary pre-cooking, secondary steaming, marinating broth preparation, low-temperature marinating, sterilization, and other processing steps. Through a combined process of "medium-high temperature pre-cooking - precise steaming - rapid cooling," the runny yolk ratio of the egg is consistently maintained above 80%. The resulting selenium-enriched runny-yolk marinated egg exhibits stable selenium content, is safe and healthy, has a semi-liquid runny yolk, and a rich marinating aroma.

[0006] To achieve the above objectives, the present invention provides a method for preparing selenium-enriched soft-boiled marinated eggs, comprising the following steps: (1) Select fresh, undamaged selenium-enriched poultry eggs, sterilize and disinfect them, and wash them for later use; (2) The washed selenium-enriched poultry eggs are subjected to a two-stage steaming process. First, they are pre-cooked at 60-65℃ for 5-10 minutes, then heated to 95-100℃ for 5-10 minutes, and finally quickly immersed in 0-4℃ ice water to cool for 12-15 minutes. The shells are then removed to obtain soft-boiled egg blanks. The soft-boiled egg blanks have a yolk softness of 80-85% and are in a semi-fluid colloidal state. (3) Prepare selenium-enriched brine, add rice wine and adjust the pH value to 5.4~6.5, add organic selenium source, completely immerse the soft-boiled egg blanks in the brine, and use low-temperature pickling process to pickle at 4~10℃ for 12~18 h; the amount of organic selenium source added is 0.05-0.35mg / Kg of the brine mass, calculated as selenium element.

[0007] (4) Take out the marinated soft-boiled eggs, drain the surface marinade, sterilize at low temperature and vacuum pack to obtain the finished selenium-enriched soft-boiled eggs.

[0008] In this invention, the yolk soft-boiled marinated eggs prepared by the method described in this invention have a yolk softness of 80-85%, the yolk is in a semi-fluid colloidal state, and the selenium content of the finished product is 0.20-0.29 mg / kg.

[0009] Further, in step (1), the selenium-enriched poultry eggs are selected from one or more of selenium-enriched chicken eggs, selenium-enriched duck eggs, and selenium-enriched quail eggs.

[0010] Furthermore, in step (2), the heating rate to 95~100℃ is 5.0~9.4℃ / min.

[0011] Furthermore, in step (2), 0.1~0.2wt% of food-grade antioxidant is added to the ice water. The food-grade antioxidant is one or a combination of sodium ascorbate and tea polyphenols.

[0012] Further, in step (3), the selenium-enriched brine is prepared by weight of the following components: 120-130 parts of deionized water, 0.0003-0.026 parts of organic selenium source, 0.3-1 parts of spices, 20-30 parts of seasoning, 1-2 parts of color protectant, and 4-6 parts of deodorizing and flavor-enhancing agent.

[0013] Furthermore, the organic selenium source is one or a combination of two of selenium-enriched yeast and selenized carrageenan, wherein the amount of selenium-enriched yeast alone is 0.003 to 0.026 parts, and the amount of selenized carrageenan alone is 0.0003 to 0.0015 parts.

[0014] Furthermore, the spices are composed of the following ingredients in parts by weight: 3-5 parts star anise, 3-5 parts bay leaves, 3-5 parts cinnamon, 1-3 parts Sichuan peppercorns, 3-5 parts cardamom, 1-3 parts fennel seeds, 3-5 parts dried chili peppers, 1-3 parts cloves, 1-3 parts amomum villosum, 3-5 parts dried ginger, 3-5 parts gardenia, 3-5 parts dried tangerine peel, 3-5 parts dried hawthorn, and 10-15 parts dried shiitake mushrooms.

[0015] Furthermore, the seasoning is a mixture of light soy sauce, salt, and white sugar in a mass ratio of (15~20):(2.5~3):(4~6), the color protectant is dark soy sauce, and the deodorizing and flavor-enhancing agent is Shaoxing wine.

[0016] Furthermore, in step (4), the low-temperature sterilization adopts pasteurization process, the sterilization temperature is 65-70℃, the sterilization time is 30-50 minutes, and after sterilization, it is rapidly cooled to 10-15℃, and the vacuum degree of vacuum packaging is not less than 0.08MPa.

[0017] Furthermore, the selenium content of the finished selenium-enriched soft-boiled marinated eggs is 0.20~0.29 mg / kg.

[0018] The second aspect of this invention provides a selenium-enriched soft-boiled marinated egg, prepared using the preparation method described in this invention. The egg white of the marinated egg has a water content of 80.0-88.0%, and the yolk has a water content of 42.0-55.0%. Based on dry basis selenium content, selenium can be detected in both the egg white and yolk of the marinated egg, and the uniformity of the distribution of selenium content in the egg white and yolk does not exceed 35%.

[0019] The third aspect of this invention provides the application of the preparation method described herein in the preparation of ready-to-eat selenium-enriched soft-boiled eggs, portable selenium-enriched soft-boiled eggs, breakfast-grade selenium-enriched soft-boiled eggs, or health-enhancing selenium-enriched soft-boiled eggs.

[0020] Furthermore, in the application, the concentration of selenium in the selenium-enriched brine is adjusted according to the needs of the target population, so that the selenium content of the finished braised eggs is adapted to the intake needs of different groups; among them, the selenium content of the children's version is 0.20~0.24mg / kg, and the selenium content of the adult version is 0.20~0.29mg / kg.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The innovative two-stage cooking process of “low-temperature pre-cooking + high-temperature steaming” is adopted. The egg white is pre-cooked at 60-65℃ for 5-10 minutes to initially set the shape, and the yolk is steamed at 95-100℃ for 5-10 minutes to precisely control the softness of the yolk. This effectively avoids the problem of softness deviation caused by traditional cooking process, so that the finished product has a uniform color and a stable semi-fluid state, and the softness rate can reach more than 80%.

[0022] (2) The low-temperature 4-10℃ pickling process not only promotes the full penetration of flavor substances in the brine, but also reduces the heat loss of nutrients, especially reducing the loss of selenium caused by high temperature, so that the selenium content of the finished product is stable and meets the standard; the subsequent 45-60℃ drying and 65-70℃ low-temperature pasteurization are combined to remove excess surface moisture and extend shelf life, while avoiding the damage of high temperature to the soft texture, and the sterilization is thorough, meeting food hygiene standards and improving the safety of the product for consumption.

[0023] (3) From raw material sterilization, precise steaming, low-temperature pickling to drying, packaging and pasteurization, a complete and quantifiable production process is formed. Each process parameter is clearly defined (such as steaming temperature, pickling time, sterilization conditions, etc.), which facilitates standardized operation in the factory, solves the problem of large quality fluctuations in traditional handmade production, and provides strong support for large-scale production and market promotion of products. Attached Figure Description

[0024] Figure 1 shows the soft-boiled state of selenium-enriched marinated eggs at different steaming times; Figure 2 is a schematic diagram of the calculation method for the soft-boiled consistency of marinated eggs; Figure 3 shows a comparison of the effects of steaming and cooking on the total selenium content of soft-boiled eggs (dry basis). Figure 4 is a process flow diagram for preparing selenium-enriched soft-boiled marinated eggs in a preferred embodiment of the present invention. Detailed Implementation

[0025] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] Unless otherwise stated, all terms "parts" in this document refer to parts by weight; all percentages refer to mass percentages; all temperatures refer to the set temperature of the processing medium or processing equipment; and all times refer to the actual processing time calculated from the time the sample enters the corresponding processing environment. "Selenium-enriched poultry eggs" in this document include one or more of selenium-enriched chicken eggs, selenium-enriched duck eggs, and selenium-enriched quail eggs. "Organic selenium sources" in this document include one or more of selenium-enriched yeast, selenized carrageenan, etc., in combination. "Seasoning agents" in this document include light soy sauce, salt, and white sugar; "color-protecting agents" include dark soy sauce; and "fishy-smelling and flavor-enhancing agents" include Shaoxing wine.

[0027] The term "soft-boiled egg" in this article refers to an egg that, after two-stage cooking and rapid cooling, has formed a complete gel structure in the egg white, while the center of the yolk remains semi-fluid, colloidal, or not fully solidified. The term "softness" characterizes the proportion of the not-fully-solidified area in the center of the yolk to the overall cross-section of the yolk. It can be calculated by cutting the sample along its long axis and measuring the long axis of the soft-boiled area in the center of the yolk and the overall long axis of the yolk. The calculation formula is as follows: X = S1 / S2 × 100% In the formula, X represents the degree of softness (%), S1 represents the major axis of the incompletely solidified area in the center of the yolk (mm), and S2 represents the major axis of the overall cross-section of the yolk (mm).

[0028] The "selenium retention rate" mentioned in this article is used to characterize the retention of selenium in the processed product relative to the raw material. The calculation formula is as follows: R = C1×M1 / (C0×M0)×100% In the formula, R is the selenium retention rate (%), C1 is the selenium content of the processed sample, M1 is the mass of the processed sample, C0 is the selenium content of the raw material before processing, and M0 is the mass of the raw material before processing. C0 and C1 can be expressed using the same measurement standard.

[0029] The "distribution uniformity deviation of selenium in egg white and yolk" mentioned in this article is used to characterize the relative difference in selenium content between egg white and yolk in the finished product. The calculation formula is as follows: D =|C 蛋清 C 蛋黄 | / [(C 蛋清 +C 蛋黄 ) / 2]×100% In the formula, D is the distribution uniformity deviation, %; C 蛋清 Selenium content in egg white; C 蛋黄 This refers to the selenium content in egg yolks. (C) 蛋清 and C 蛋黄 Preferably calculated on a dry basis.

[0030] In this invention, the total selenium content can be determined using hydride generation-atomic fluorescence spectrometry, inductively coupled plasma mass spectrometry, or other methods for detecting selenium content in food; the moisture content can be determined using direct drying or other methods for determining food moisture content; and the total bacterial count can be determined using food microbiology testing methods. Specific detection methods do not constitute a limitation on the scope of protection of this invention, as long as they can accurately characterize the selenium content, moisture content, and microbial control effect of the finished product.

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Unless otherwise specified, the raw materials used in the following embodiments are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0033] Example 1 like Figure 1 As shown, a preferred embodiment of the present invention provides a method for preparing selenium-enriched soft-boiled marinated eggs, comprising: (1) Weighing: Take 100 portions of fresh selenium-enriched eggs (52-55g / egg, selenium content ≥25μg / 100g), 0.4 portions of spices (spice composition: 3 portions of star anise, 3 portions of bay leaves, 3 portions of cinnamon, 1 portion of Sichuan pepper, 3 portions of cardamom, 1 portion of fennel, 3 portions of dried chili, 1 portion of cloves, 1 portion of amomum villosum, 3 portions of dried ginger, 3 portions of gardenia, 3 portions of dried tangerine peel, 3 portions of dried hawthorn, 10 portions of dried shiitake mushrooms, mix and grind), 18 portions of light soy sauce, 1.5 portions of dark soy sauce, 5.5 portions of rice wine, 2.8 portions of salt, and 5 portions of white sugar; soak the fresh selenium-enriched eggs in a 0.3% sodium hypochlorite solution for 5 minutes to sterilize and disinfect, then rinse with running water until there is no residue, drain the surface water and set aside. (2) Cooking: First stage of pre-cooking: Place the pre-treated fresh selenium-enriched eggs in a water bath at a constant temperature of 65℃ and cook continuously for 8 minutes to ensure that the eggs are heated evenly; Second stage of steaming: Quickly transfer the pre-cooked eggs into a constant temperature steamer that has been heated to 100℃ and steam for 8 minutes; After steaming, immediately remove the eggs and place them in 4℃ cold water (0.2wt% tea polyphenols) to cool for 12 minutes to allow the eggs to cool down and set quickly. (3) Brine: Add spices to 1.2 times the total weight of selenium-enriched eggs in purified water (i.e., 120 parts water), heat over high heat until boiling, then reduce to low heat and simmer for 45 minutes; then add salt, sugar, light soy sauce, and dark soy sauce, and continue to simmer over low heat for 60 minutes. Filter with gauze to remove spice residue, let cool naturally to 35°C, then add Shaoxing wine and selenized carrageenan, stir well and set aside. The resulting brine has a pH of 6.2 and a selenium content of 0.15 mg / kg. (4) Marinating: Gently crack the eggshell after cooling, peel it along the seam of the eggshell to obtain a complete soft-boiled egg blank; put the egg blank into the cold brine of step (3), ensuring that the brine completely submerges the egg body, and marinate at 8°C for 15 hours. (5) Finished product: Take out the marinated eggs and put them in a 50℃ oven to dry the surface moisture (drying time 35min, until the surface of the egg is slightly dry and not sticky); vacuum pack them with food-grade composite plastic film, and then place them in a 68℃ water bath for low-temperature pasteurization for 40 minutes; after sterilization, cool them naturally to room temperature, and the finished product is obtained after passing the sensory and microbiological index tests. According to the test results, the selenium content of the finished selenium-enriched soft-boiled braised eggs in this embodiment is ≥25.81μg / 100g, and the selenium retention rate is 93.54%; the soft-boiled area in the center of the yolk accounts for 80%, and it is in a uniform orange-yellow semi-fluid state; the sensory evaluation shows that the braised eggs have a rich braised aroma without any off-flavors, the egg white is firm and elastic, and the egg yolk is delicate and smooth.

[0034] Selenized carrageenan, as an organic selenium source for brine, can serve as an alternative to selenium-enriched yeast as an organic selenium supplement. Selenized carrageenan already has national food safety standards, with GB 1903.23—2016 being the currently valid standard.

[0035] Example 2 (1) Weighing: Take 100 portions of fresh selenium-enriched quail eggs (egg weight 10-15g / egg, selenium content ≥25μg / 100g), adjust the amount of spices to 0.4 portions (spice composition is the same as in Example 1), 20 portions of light soy sauce, 2 portions of dark soy sauce, 6 portions of rice wine, 3 portions of salt, and 6 portions of white sugar; the sterilization and disinfection method is the same as in Example 1; (2) Cooking: The first stage of pre-cooking temperature is 65℃ and the pre-cooking time is 5 minutes; the second stage of steaming temperature is 100℃ and the steaming time is 3 minutes; the cooling conditions are the same as in Example 1; (3) The amount of water added to the braising spices is 1.3 times the total mass of the quail eggs (130 parts water), and the cooking time of the spices is extended to 60 minutes. The remaining braising preparation steps are the same as in Example 1. (4) Marinating: Gently crack the eggshell after cooling, peel it along the seam of the eggshell to obtain a complete soft-boiled quail egg blank; put the egg blank into the cold brine of step S2, ensuring that the brine completely submerges the egg, and marinate at 8°C for 18 hours. (5) Finished product: The steps are the same as in Example 1; Testing revealed that the finished selenium-enriched soft-boiled marinated quail eggs from this embodiment contained 28.66 μg / 100g of selenium, with a selenium retention rate of 91.77%. The soft-boiled yolk area accounted for 80% of the total yolk, resulting in a smooth and creamy texture. The marinade flavor blended harmoniously with the quail egg's own flavor, with no fishy taste, making it suitable for consumers who prefer strong flavors. This demonstrates that the method of this invention has good adaptability to different poultry eggs.

[0036] Example 3 This embodiment uses fresh selenium-enriched duck eggs as raw materials, and adjusts the process parameters to suit the characteristics of the eggs. The specific steps are as follows: (1) Weighing: Take 100 portions of fresh selenium-enriched duck eggs (egg weight 65~70g / egg, selenium content ≥25μg / 100g), adjust the amount of spices to 0.4 portions (spice composition is the same as in Example 1), 20 portions of light soy sauce, 2 portions of dark soy sauce, 6 portions of rice wine, 3 portions of salt, and 6 portions of white sugar; the sterilization and disinfection method is the same as in Example 1; (2) Cooking: The first stage of pre-cooking temperature is 65℃ and the pre-cooking time is 10 minutes; the second stage of steaming temperature is 100℃ and the steaming time is 9 minutes; the cooling conditions are the same as in Example 1; (3) The amount of water added to the braising spices is 1.3 times the total mass of the duck eggs (130 parts water), and the cooking time of the spices is extended to 60 minutes. The remaining braising preparation steps are the same as in Example 1. (4) Marinating: Gently crack the eggshell after cooling, peel it along the seam of the eggshell to obtain a complete soft-boiled egg blank; put the egg blank into the cold brine of step (3), ensuring that the brine completely submerges the egg body, and marinate at 8°C for 18 hours. (5) Finished product: The steps are the same as in Example 1; Testing revealed that the finished selenium-enriched soft-boiled marinated duck eggs from this embodiment contained 26.79 μg / 100g of selenium, with a selenium retention rate of 94.36%. The soft-boiled yolk area accounted for 85% of the total yolk, resulting in a smooth and creamy texture. The marinade flavor blended harmoniously with the duck egg's own flavor, with no fishy smell, making it suitable for consumers who prefer strong flavors. This demonstrates that the method of this invention has good adaptability to different poultry eggs.

[0037] Example 4 (1) Weighing and pretreatment of raw materials: Take 100 parts of fresh selenium-enriched quail eggs by weight, with an egg weight of 10-15 g / egg and a selenium content of ≥25 μg / 100 g; take 120 parts of deionized water, 0.5 parts of spices, 15 parts of light soy sauce, 2.5 parts of salt, 4 parts of white sugar, 1 part of dark soy sauce, and 4 parts of rice wine; the spices are composed of star anise, bay leaves, cinnamon, Sichuan pepper, cardamom, fennel, dried chili, cloves, amomum villosum, dried ginger, gardenia, tangerine peel, dried hawthorn and dried shiitake mushrooms; soak the fresh selenium-enriched quail eggs in a 0.3% sodium hypochlorite solution for 5 min, then rinse with running water until there is no obvious residue, drain and set aside. (2) Two-stage steaming process: The pre-treated selenium-enriched quail eggs were placed in a 60°C water bath for 5 minutes; then transferred to a steamer heated to 95°C for 5 minutes; after steaming, they were immediately removed and placed in 0°C ice water (0.2wt% tea polyphenols) for 12 minutes to cool. After shelling, soft-boiled egg blanks were obtained. (3) Preparation of selenium-enriched brine: Add spices to deionized water, heat to boiling, then simmer for 45 minutes; add light soy sauce, salt, white sugar and dark soy sauce, continue to simmer for 30 minutes, filter, and cool to below 40℃; then add rice wine and selenium-enriched yeast, stir well, adjust the pH of the brine to 5.4, and obtain selenium-enriched brine with a selenium content of 0.05 mg / Kg; (4) Vacuum low-temperature braising: The soft-boiled egg blanks obtained in step (2) are completely immersed in the selenium-rich braising liquid obtained in step (3) and vacuum low-temperature braising is carried out for 2 hours under an absolute pressure of 0.03 MPa and a temperature of 45°C. (5) Sterilization and packaging: Take out the selenium-enriched soft-boiled quail eggs after braising, drain the surface braising liquid, and vacuum pack them; then place them in a 65℃ water bath for low-temperature sterilization for 30 min, and then quickly cool them to below 10℃ to obtain the finished selenium-enriched soft-boiled braised quail eggs. Testing revealed that the finished selenium-enriched soft-boiled marinated quail eggs from this embodiment contained 28.63 μg / 100g of selenium, with a selenium retention rate of 91.68%. The soft-boiled yolk area accounted for 80% of the total yolk, resulting in a smooth and creamy texture. The marinade flavor blended harmoniously with the quail egg's own flavor, with no fishy taste, making it suitable for consumers who prefer strong flavors. This demonstrates that the method of this invention has good adaptability to different poultry eggs.

[0038] In this embodiment, selenium-enriched yeast is used as a supplementary source of organic selenium in the brine to improve the supply level of organic selenium in the brine. There are national food safety standards for selenium-enriched yeast, which stipulate that the total selenium content should be 1000–2500 mg / kg, and the percentage of organic selenium in the total selenium content should not be less than 97%.

[0039] Example 5 (1) Weighing and pretreatment of raw materials: Take 100 portions of fresh selenium-enriched eggs by weight, with an egg weight of 52-55 g / egg and a selenium content of ≥25 μg / 100 g; take 125 portions of deionized water, 0.8 portions of spices, 18 portions of light soy sauce, 2.8 portions of salt, 5 portions of white sugar, 1.5 portions of dark soy sauce, and 5 portions of Shaoxing wine; soak the fresh selenium-enriched eggs in a 0.3% sodium hypochlorite solution for 5 min, then rinse with running water until there is no obvious residue, drain and set aside. (2) Two-stage steaming process: The pre-treated selenium-enriched eggs were placed in a 63°C water bath for 8 minutes; then transferred to a steamer heated to 98°C for 8 minutes; after steaming, they were immediately removed and placed in 2°C ice water (0.2wt% tea polyphenols) for 14 minutes to cool. After peeling, soft-boiled egg blanks were obtained. (3) Preparation of selenium-enriched brine: Add spices to deionized water, heat to boiling, then simmer for 50 minutes; add light soy sauce, salt, white sugar and dark soy sauce, continue to simmer for 45 minutes, filter, and cool to below 40°C; then add rice wine and selenium-enriched yeast, stir well, adjust the pH of the brine to 6.0, and obtain selenium-enriched brine with a selenium content of 0.20 mg / Kg; (4) Vacuum low-temperature braising: The soft-boiled egg blanks obtained in step (2) are completely immersed in the selenium-rich braising liquid obtained in step (3) and vacuum low-temperature braising is carried out for 3 h under an absolute pressure of 0.04 MPa and a temperature of 50°C. (5) Sterilization and packaging: Take out the selenium-enriched soft-boiled braised eggs after braising, drain the surface braising liquid, and vacuum pack them; then place them in a 68℃ water bath for low-temperature sterilization for 40 min, and then quickly cool them to below 10℃ to obtain the finished selenium-enriched soft-boiled braised eggs. According to the test results, the selenium content of the finished selenium-enriched soft-boiled braised eggs in this embodiment is 26.16 μg / 100g, and the selenium retention rate of the egg source is 94.82%; the soft-boiled area in the center of the yolk accounts for 80%, and it is in a uniform orange-yellow semi-fluid state; the sensory evaluation shows that the braised eggs have a rich braised aroma without any off-flavors, the egg white is firm and elastic, and the egg yolk is delicate and smooth.

[0040] Example 6 (1) Weighing and pretreatment of raw materials: Take 100 portions of fresh selenium-enriched duck eggs by weight, with an egg weight of 65-70 g / egg and a selenium content of ≥25 μg / 100 g; take 130 portions of deionized water, 1 portion of spices, 20 portions of light soy sauce, 3 portions of salt, 6 portions of white sugar, 2 portions of dark soy sauce, and 6 portions of Shaoxing wine; soak the fresh selenium-enriched duck eggs in a 0.3% sodium hypochlorite solution for 5 min, then rinse with running water until there is no obvious residue, drain and set aside. (2) Two-stage steaming process: The pre-treated selenium-enriched duck eggs were placed in a 65°C water bath for 10 min; then transferred to a steamer heated to 100°C for 10 min; after steaming, they were immediately removed and placed in 4°C ice water (0.2wt% tea polyphenols) for 15 min to cool. After shelling, soft-boiled egg blanks were obtained. (3) Preparation of selenium-enriched brine: Add spices to deionized water, heat to boiling, then simmer for 60 minutes; add light soy sauce, salt, white sugar and dark soy sauce, continue to simmer for 60 minutes, filter, and cool to below 40℃; then add rice wine and selenium-enriched yeast, stir well, adjust the pH of the brine to 6.5, and obtain selenium-enriched brine with a selenium content of 0.35 mg / Kg; (4) Vacuum low-temperature braising: The soft-boiled egg blanks obtained in step (2) are completely immersed in the selenium-rich braising liquid obtained in step (3) and vacuum low-temperature braising is carried out for 4 hours under an absolute pressure of 0.05 MPa and a temperature of 55°C. (5) Sterilization and packaging: Take out the selenium-enriched soft-boiled braised duck eggs after braising, drain the surface braising liquid, and vacuum pack them; then place them in a 70℃ water bath for low-temperature sterilization for 50 min, and after sterilization, quickly cool them to below 10℃ to obtain the finished selenium-enriched soft-boiled braised duck eggs. Testing revealed that the selenium content of the finished selenium-enriched soft-boiled marinated duck eggs from this embodiment was 27.21 μg / 100g, with a selenium retention rate of 95.82%. The soft-boiled yolk area accounted for 85% of the total yolk, resulting in a smooth and creamy texture. The marinade flavor blended harmoniously with the duck egg's own flavor, with no fishy smell, making it suitable for consumers who prefer strong flavors. This demonstrates that the method of this invention has good adaptability to different poultry eggs.

[0041] Performance testing like Figure 2 As shown, the soft-boiled state of selenium-enriched marinated eggs varies depending on the steaming time; for example... Figure 3 The effects of boiling and steaming in the shell on the selenium content of fresh selenium-enriched eggs are shown. Key indicators were tested on the finished products of Examples 1-3 and the comparative sample of Example 2. The testing methods and results are as follows: (1) Selenium content detection: The selenium content was determined by hydride generation-atomic fluorescence spectrometry (GB 5009.93-2017). The selenium content of the finished products in Examples 1, 2, and 3 were 25.81 μg / 100g, 28.66 μg / 100g, and 26.79 μg / 100g, respectively, with selenium retention rates of 93.54%, 91.77%, and 94.36%, respectively; the selenium content of the finished product in Comparative Example 1 was 20.48 μg / 100g, with a selenium retention rate of 75.51%; and the selenium content of the finished product in Comparative Example 2 was 18.85 μg / 100g, with a selenium retention rate of 68.32%. The results show that the method of the present invention is more effective than the traditional single boiling or boiling water brine process in preserving the selenium element in selenium-enriched poultry eggs.

[0042] (2) Evaluation of Soft-Cooked State: The ratio of the diameter of the soft-cooked area of ​​the yolk to the total diameter of the yolk (soft-cooking rate) was measured using vernier calipers. Combined with sensory evaluation (out of 10 points, scoring criteria: uniformity of soft-cooked state 4 points, taste 3 points, color 3 points), Example 1 had a soft-cooking rate of 80% and a sensory score of 9.2 points; Example 2 had a soft-cooking rate of 80% and a sensory score of 9.2 points; Example 3 had a soft-cooking rate of 85% and a sensory score of 9.0 points; and the comparative example had a soft-cooking rate of 80% and a sensory score of 8.9 points. This indicates that the two-stage cooking method can precisely control the yolk coagulation degree. The method for measuring soft-cooked state is described in [link to relevant documentation]. Figure 4 The relevant test data are shown in Table 1 (Selenium content and soft-boiled index): Table 1 Comparative Example 1 The difference between this comparative example and Example 1 is that step (2) uses a traditional single cooking process instead of two-stage steaming and cooking. Specifically, the pre-treated eggs are directly put into boiling water (100°C) and cooked for 8 minutes. The other ingredient ratios and operating steps are completely consistent with Example 1. Testing revealed that the selenium content of the finished braised eggs in this embodiment was reduced to 20.48 μg / 100g, with a selenium retention rate of only 75.51%. Other indicators showed no significant difference from those in Example 1.

[0043] Comparative Example 2 The difference between this comparative example and Example 1 is that: after steaming in step (2), the eggs are not immediately put into 4°C cold water to cool for 12 minutes, but are placed at room temperature to cool naturally for 30 minutes; the remaining raw material ratios, brine preparation, low-temperature marinating, drying, packaging and sterilization steps are the same as in Example 1. The soft-boiled state of the obtained product was evaluated. The results showed that, compared with Example 1, the soft-boiledness of the egg yolk center of the product obtained in this comparative example was only 27.1%. The egg yolk further changed from a semi-fluid colloidal state to a semi-solid state, the flowability of the cut surface decreased, and the uniformity of the soft-boiled state decreased.

[0044] Comparative Example 3 The difference between this comparative example and Example 1 is that: in step (4), instead of using 8°C for 15 hours of low-temperature marinating, the soft-boiled egg blanks are placed in 65°C brine for 12 hours of heat preservation; the remaining raw material ratios, two-stage steaming, cooling, drying, packaging and sterilization steps are the same as in Example 1. The resulting product was evaluated for its soft-boiled state. The results showed that, compared with Example 1, the soft-boiled state of the egg yolk in this comparative example was 50.6%, the viscosity of the egg yolk center increased, and the semi-fluid state weakened.

[0045] Comparative Example 4 The difference between this comparative example and Example 1 is that step (4) adopts the traditional boiling water braising method, specifically, the steamed egg embryos are directly placed into boiling brine (100°C) and braised for 60 minutes. The other ingredient ratios and operating steps are completely consistent with Example 1. Testing revealed that the selenium content of the finished braised eggs in this comparative example was reduced to 18.85 μg / 100g, with a selenium retention rate of only 68.32%, a softness of 0%, and a sensory score of 6.7. Other indicators showed no significant difference from those in Example 1.

[0046] Comparative Example 5 The difference between this comparative example and Example 1 is that the low-temperature pasteurization conditions in step (5) are adjusted from 68°C and 40 min to 75°C and 40 min; the remaining raw material ratios, two-stage cooking, cooling, brine preparation, low-temperature marinating, drying and packaging steps are the same as in Example 1. The resulting product was evaluated for its soft-boiled state. The results showed that, compared with Example 1, the soft-boiled state of the egg yolk in this comparative example was 68.3%, the fluidity of the egg yolk center was reduced, the overall coagulation degree of the egg yolk was increased, and the sensory manifestation was that the egg yolk tasted drier and the smoothness and delicacy were reduced.

[0047] The above description is merely a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations that are directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A method for preparing selenium-enriched soft-boiled marinated eggs, characterized in that, Includes the following steps: (1) Select fresh, undamaged selenium-enriched poultry eggs, sterilize and disinfect them, and wash them for later use; (2) The washed selenium-enriched poultry eggs are subjected to a two-stage steaming process. First, they are pre-cooked at 60-65℃ for 5-10 minutes, then heated to 95-100℃ for 5-10 minutes, and finally quickly immersed in 0-4℃ ice water to cool for 12-15 minutes. The shells are then removed to obtain soft-boiled egg blanks. The soft-boiled egg blanks have a yolk softness of 80-85% and are in a semi-fluid colloidal state. (3) Prepare selenium-enriched brine, add rice wine and adjust the pH value to 5.4~6.5, add organic selenium source, completely immerse the soft-boiled egg blanks in the brine, and use low-temperature pickling process to pickle at 4~10℃ for 12~18 h; the amount of organic selenium source added is 0.05-0.35mg / Kg of the brine mass, calculated as selenium element. (4) Take out the marinated soft-boiled eggs, drain the surface marinade, sterilize at low temperature and vacuum pack to obtain the finished selenium-enriched soft-boiled eggs.

2. The preparation method according to claim 1, characterized in that, In step (1), the selenium-enriched poultry eggs are selected from one or more of selenium-enriched chicken eggs, selenium-enriched duck eggs, and selenium-enriched quail eggs.

3. The preparation method according to claim 1, characterized in that, In step (2), the heating rate to 95~100℃ is 5.0~9.4℃ / min; and / or, 0.1~0.2wt% of food-grade antioxidant is added to the ice water, wherein the food-grade antioxidant is one or a combination of sodium ascorbate and tea polyphenols.

4. The preparation method according to claim 1, characterized in that, In step (3), the selenium-enriched brine is prepared by the following components in parts by weight: 120-130 parts of deionized water, 0.0003-0.026 parts of organic selenium source, 0.3-1 parts of spices, 20-30 parts of seasoning, 1-2 parts of color protectant, and 4-6 parts of deodorizing and flavor-enhancing agent.

5. The preparation method according to claim 4, characterized in that, The organic selenium source is one or a combination of two of selenium-enriched yeast and selenized carrageenan, wherein the amount of selenium-enriched yeast alone is 0.003–0.026 parts, and the amount of selenized carrageenan alone is 0.0003–0.0015 parts; and / or The spices are composed of the following ingredients in parts by weight: star anise 3-5 parts, bay leaves 3-5 parts, cinnamon 3-5 parts, Sichuan peppercorns 1-3 parts, cardamom 3-5 parts, fennel seeds 1-3 parts, dried chili peppers 3-5 parts, cloves 1-3 parts, amomum villosum 1-3 parts, dried ginger 3-5 parts, gardenia 3-5 parts, dried tangerine peel 3-5 parts, dried hawthorn 3-5 parts, and dried shiitake mushrooms 10-15 parts; and / or The seasoning is a mixture of light soy sauce, salt, and white sugar in a mass ratio of (15~20):(2.5~3):(4~6), the color protectant is dark soy sauce, and the deodorizing and flavor-enhancing agent is Shaoxing wine.

6. The preparation method according to claim 1, characterized in that, In step (4), the low-temperature sterilization adopts pasteurization process, the sterilization temperature is 65-70℃, the sterilization time is 30-50 minutes, and after sterilization, it is rapidly cooled to 10-15℃, and the vacuum degree of vacuum packaging is not less than 0.08MPa.

7. The preparation method according to claim 1, characterized in that, The finished selenium-enriched soft-boiled marinated eggs have a selenium content of 0.20~0.29 mg / kg.

8. A selenium-enriched soft-boiled marinated egg, characterized in that, The braised egg is prepared by any one of the preparation methods described in claims 1-7. The water content of the egg white is 80.0-88.0%, and the water content of the egg yolk is 42.0-55.0%. Based on dry basis selenium content, selenium can be detected in both the egg white and the egg yolk of the braised egg, and the uniformity of the distribution of selenium content in the egg white and the egg yolk does not exceed 35%.

9. The application of the preparation method according to any one of claims 1-7 in the preparation of ready-to-eat selenium-enriched soft-boiled eggs, portable selenium-enriched soft-boiled eggs, breakfast-grade selenium-enriched soft-boiled eggs, or health-enhancing selenium-enriched soft-boiled eggs.

10. The application according to claim 9, characterized in that, In this application, the concentration of selenium in the selenium-enriched brine is adjusted according to the needs of the target population, so that the selenium content of the finished braised eggs is suitable for the intake needs of different groups. The selenium content of the children's version is 0.20~0.24mg / kg, and the selenium content of the adult version is 0.20~0.29mg / kg.

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