High-temperature-resistant egg white, preparation method and application thereof

Abstract

The application belongs to the technical field of food processing, and particularly relates to a high-temperature-resistant egg liquid, a preparation method and application. The application aims at the problems of gelation, fishy smell, low sterilization temperature and short shelf life at room temperature of the existing egg liquid, and through the combination of protease hydrolysis treatment, sugar addition and dispersion treatment, the sterilization temperature of the prepared high-temperature-resistant egg liquid is increased to 77-82 DEG C, the high-temperature-sterilized egg liquid does not form gel and does not produce fishy smell, the shelf life at room temperature is effectively prolonged to 25-30 days, and the high-temperature-resistant egg liquid has excellent quality and processing performance. The high-temperature-resistant egg liquid is applied, and the egg product prepared by further processing after high-temperature sterilization has rich egg liquid flavor and good organization state.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a high-temperature resistant egg liquid, its preparation method, and its application. Background Technology

[0002] Egg liquid, made from crushed and processed eggshells, is packaged as a substitute for fresh eggs. It is rich in essential amino acids, minerals, vitamins, folic acid, and other bioactive substances, offering a comprehensive range of nutrients. In the food industry, egg liquid is frequently used as a raw material in the production of various foods such as dairy products, baked goods, pastries, and beverages. The development of various functional egg-based snacks is receiving increasing attention. However, egg liquid has a high moisture content and is highly susceptible to microbial contamination and spoilage at room temperature. Therefore, heating is often used for sterilization in production. However, temperatures above 60℃ cause the proteins in egg liquid to denature and form a gel. Temperatures above 70℃ not only cause gel formation but also decompose sulfur-containing proteins, producing hydrogen sulfide, which slowly develops a fishy odor. This not only impairs its processing performance but also severely reduces its sensory quality, limiting its application in food processing. To ensure the quality and processing performance of egg liquid, current technology generally uses a temperature of 60-65℃ for 2-3 minutes for sterilization. After sterilization, the shelf life of egg liquid at room temperature is only 5-7 days. Summary of the Invention

[0003] For the reasons mentioned above, one of the objectives of this invention is to provide a heat-resistant egg liquid and its preparation method. The heat resistance of the egg liquid is significantly improved by the combined effects of protease hydrolysis, sugar addition, and dispersion treatment, so that the sterilization temperature of the prepared heat-resistant egg liquid is increased to 77-82℃. The egg liquid after high-temperature sterilization will not form a gel or produce a fishy smell. The shelf life at room temperature is effectively extended to 25-30 days, and it has excellent quality and processing performance.

[0004] The second objective of this invention is to provide the application of the above-mentioned heat-resistant egg liquid, wherein the egg products prepared by further processing after high-temperature sterilization of the heat-resistant egg liquid have a rich egg flavor and good texture.

[0005] To achieve the above objectives, the first technical means of the present invention provides a method for preparing high-temperature resistant egg liquid, including...

[0006] It is obtained by adding sugar to egg liquid and then dispersing it.

[0007] Furthermore, the addition of sugar includes a process involving protease hydrolysis.

[0008] Furthermore, the protease includes one or more of papain, bromelain, flavor protease, trypsin, pepsin, cathepsin, Bacillus subtilis protease, and aspartic protease.

[0009] Furthermore, the sugar is one or more of tetracarbon sugars, pentose sugars, and their sugar alcohols.

[0010] Furthermore, the tetracarbon sugar and its sugar alcohol include erythritol, threose, and erythritol.

[0011] Furthermore, the pentose sugars and their sugar alcohols include xylose, arabinose, ribose, and xylitol.

[0012] Furthermore, the dispersion treatment is one or more of the following: microfluidic homogenization treatment, ultrasonic treatment, colloid milling treatment, high-shear emulsification treatment, and high-voltage electric field treatment.

[0013] Furthermore, a high-temperature resistant egg liquid was prepared according to the above preparation method.

[0014] The second technical means of this application provides the application of the above-mentioned high-temperature resistant egg liquid.

[0015] The present invention also provides egg products prepared by high-temperature sterilization of the above-mentioned heat-resistant egg liquid.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. This invention addresses the problem that existing egg liquids, after sterilization at 60℃ or higher, gradually form a gel and develop a fishy odor, resulting in a short shelf life at room temperature. Firstly, it improves the heat resistance of the egg liquid by adding protease to hydrolyze some proteins. Then, it adds small-molecule tetracarbon and pentose sugars and their sugar alcohols, dispersing them so that the unhydrolyzed proteins exist in the egg liquid as tiny particles, and a protective film forms on the protein surface, ensuring protein stability and further improving the heat resistance of the egg liquid. This ensures that the resulting heat-resistant egg liquid maintains its complete structure and function even after sterilization at high temperatures. The sterilization temperature is increased to 77-82℃, and the egg liquid after high-temperature sterilization does not form a gel or produce a fishy odor. The shelf life at room temperature is effectively extended to 25-30 days, exhibiting excellent quality and processing performance.

[0018] 2. In this invention, the above-mentioned heat-resistant egg liquid is sterilized at 77-82℃. The egg products made from the sterilized egg liquid after further processing have a rich egg flavor and good texture. Detailed Implementation

[0019] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention.

[0020] The first embodiment of this application provides a method for preparing heat-resistant egg liquid, which includes adding sugar to the egg liquid and then dispersing it.

[0021] In some specific embodiments, the addition of sugar is further complicated by protease hydrolysis.

[0022] It should be noted that the egg liquid mentioned in this application includes egg white liquid, egg yolk liquid, or whole egg liquid.

[0023] It should be noted that the main reason for the gel formation and fishy smell in egg liquid during high-temperature sterilization is the denaturation and decomposition of proteins during heating. Existing technologies include adding proteases or sucrose to increase the sterilization temperature of the egg liquid. However, while adding proteases breaks down the proteins in the egg liquid into peptides and amino acids, thereby improving the stability of the egg liquid components and increasing its sterilization temperature, ensuring heat resistance requires thorough hydrolysis of the proteins. This necessitates specific enzyme combinations, continuous monitoring of the egg liquid's pH during enzymatic hydrolysis, and excessive hydrolysis can lead to a noticeable bitter taste, requiring subsequent bitterness removal treatment. Adding sucrose works by reacting with the denatured proteins caused by heat, thus protecting the undenatured proteins and increasing the temperature required for gel formation. However, adding up to 8% sucrose only raises the sterilization temperature of the egg liquid to around 70°C. Increasing the amount of sucrose might further increase the sterilization temperature, but excessive sucrose will inevitably lead to an excessively high sugar content in the egg liquid, affecting its quality and limiting its further processing and application in food.

[0024] In this embodiment, protease is first used to hydrolyze some of the proteins in the egg liquid into polypeptides and amino acids, improving the heat resistance of the egg liquid, delaying the formation of gel and fishy odor, and ensuring that no bitterness is produced. Then, sugar is added to the hydrolyzed egg liquid. The purpose is to utilize the hydroxyl groups of the sugar to form hydrogen bonds with the polar groups of the unhydrolyzed proteins in the egg liquid, replacing the water molecules surrounding the protein polar groups, forming a protective film on the protein surface, ensuring protein stability, maintaining its complete structure and function at high temperatures, and preventing denaturation and decomposition, thus further increasing its sterilization temperature. However, the mutual attraction between proteins and water molecules in the egg liquid makes it difficult for sugar to fully bind with the proteins. Simultaneously, the amino acid molecules produced by hydrolysis also attract the undecomposed proteins, further hindering the binding of sugar and protein. Therefore, this application disperses the sugar-containing egg liquid to separate the proteins from water molecules and hydrolyzed amino acid molecules. The proteins exist in the form of tiny particles, facilitating the binding of sugar hydroxyl groups with their polar groups, forming a protective film on the protein surface, and ensuring the protection of the proteins.

[0025] Furthermore, in this embodiment, the added sugars are tetracarbon sugars, pentose sugars, and their sugar alcohols. These sugars can fully contact the small protein particles during dispersion treatment, forming a dense protective film on the protein surface and ensuring the structure and function of the protein at higher sterilization temperatures. In the prior art, sucrose is generally added, but due to its large molecular weight, even when added in large quantities to the egg liquid of this application, it is difficult for sucrose to fully contact and bind with the protein to form a dense protective film on the protein surface, and its effect on improving the heat resistance of the egg liquid is not particularly significant. Moreover, the applicant has found that the addition of tetracarbon sugars, pentose sugars, and their sugar alcohols significantly extends the shelf life of the egg liquid at room temperature. This may be because, compared with sucrose or other large-molecule sugars (such as hexoses), or even small-molecule sugars (trioses), tetracarbon sugars, pentose sugars, and their sugar alcohols are difficult for microorganisms to utilize rapidly. At room temperature, they cannot quickly provide sufficient carbon and energy sources for the growth and reproduction of microorganisms, thus effectively improving the stability of the egg liquid at room temperature, enhancing its processing performance, and extending its shelf life at room temperature. Compared with the prior art, the high-temperature resistant egg liquid prepared in this application can improve the sterilization temperature of the egg liquid from 60-65℃ to 77-82℃ while ensuring the quality and processing performance of the egg liquid, and extend the shelf life at room temperature from 5-7 days to 25-30 days.

[0026] It is understood that the type and amount of protease added, as well as the protease hydrolysis temperature and time, can be conventionally selected by those skilled in the art based on the composition and degree of hydrolysis of the egg liquid, and do not exceed the scope of knowledge in the art. This invention does not impose any particular limitations, but only provides some preferred reference ranges. In some specific embodiments, the protease includes one or more of papain, bromelain, flavor protease, trypsin, pepsin, cathepsin, Bacillus subtilis protease, and aspartic protease; in some specific embodiments, the amount of protease added is 0.8%-1% of the egg liquid mass; in some specific embodiments, the protease hydrolysis temperature is 45-50℃, and the time is 3-4 hours.

[0027] It is understood that the sugars added in this application are tetracarbon sugars, pentose sugars, and their sugar alcohols, which have small molecular weights and cannot be rapidly utilized by microorganisms at room temperature. The type and amount of sugar added can be conventionally selected by those skilled in the art based on specific needs such as the sweetness of the egg liquid, and this does not exceed the scope of knowledge in the field. This application does not impose any particular limitations, but only provides some preferred reference ranges. In some specific embodiments, the amount of sugar added is 1.5%-2.5% of the egg liquid mass; in some specific embodiments, the tetracarbon sugars and their sugar alcohols include erythrose, thorose, and erythritol; in some specific embodiments, the pentose sugars and their sugar alcohols include xylose, arabinose, ribose, and xylitol.

[0028] It should be noted that the dispersion treatment described in this application adopts conventional solution dispersion technology. Those skilled in the art can make general adjustments to the dispersion process and parameters according to the specific conditions of the egg liquid. This application does not impose any particular limitations, but only provides some preferred embodiments. In some specific embodiments, the dispersion treatment is one or more of microfluidic homogenization, ultrasonic treatment, colloid milling, high-shear emulsification, and high-voltage electric field treatment. In some specific embodiments, the microfluidic homogenization parameters are: homogenization pressure 10-60 MPa, time 1-10 min; in some specific embodiments, the ultrasonic treatment parameters are: power 100-600 W, time 5-20 min; in some specific embodiments, the colloid milling parameters are: film mixing time 1-2 h, temperature 20-30℃; in some specific embodiments, the high-shear emulsification parameters are: rotation speed 10000-10800 r / min, time 5-10 min; in some specific embodiments, the high-voltage electric field treatment parameters are: electric field strength 800-1000 V / cm, time 60-90 min.

[0029] The second embodiment of this application provides a high-temperature resistant egg liquid prepared according to the above preparation method.

[0030] The high-temperature resistant egg liquid prepared in this embodiment will not form a gel or produce a fishy smell after being sterilized by heating at 77-82℃. It has a shelf life of 25-30 days at room temperature and has excellent quality and processing performance.

[0031] The third embodiment of this application discloses the application of the above-mentioned heat-resistant egg liquid. Using the above-mentioned heat-resistant egg liquid as a raw material, after high-temperature sterilization and further processing, the resulting egg products have good edible quality.

[0032] The fourth embodiment of this application discloses an egg product prepared using the above-mentioned heat-resistant egg liquid, which is further processed after high-temperature sterilization. The prepared egg product does not form a gel and does not produce a fishy smell, and has a good egg liquid flavor and texture, including but not limited to egg liquid fermented yogurt, egg liquid beverages, egg tarts, cakes, egg ice cream, egg pudding, and egg powder.

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit its scope.

[0034] Example 1: Preparation of High-Temperature Resistant Egg Liquid

[0035] Add 0.08 kg of papain to 10 kg of whole egg liquid and hydrolyze at 45℃ for 4 hours;

[0036] Add 0.15 kg of erythrose to the hydrolyzed whole egg liquid and mix well;

[0037] The sugared whole egg liquid is subjected to microfluidic homogenization at a pressure of 10-60 MPa for 1-10 minutes to obtain a heat-resistant whole egg liquid.

[0038] Example 2: Preparation of High-Temperature Resistant Egg Liquid

[0039] Add 0.1 kg of Bacillus subtilis protease to 10 kg of egg white solution and hydrolyze at 48°C for 3.5 h;

[0040] Add 0.25 kg of xylitol to the hydrolyzed egg white solution and mix well;

[0041] The sugared egg white solution was subjected to colloid milling, with a mixing time of 1-2 hours and a temperature of 20-30℃, to obtain a heat-resistant egg white solution.

[0042] Example 3: Preparation of High-Temperature Resistant Egg Liquid

[0043] Add 0.045 kg of flavor protease and 0.045 kg of aspartic protease to 10 kg of egg yolk liquid, and hydrolyze at 50°C for 3 hours;

[0044] Add 0.1 kg of erythritol and 0.1 kg of arabinose to the hydrolyzed egg yolk liquid and mix well;

[0045] The sugared egg yolk liquid is subjected to a high-voltage electric field treatment with an electric field strength of 800-1000V / cm for 60-90 minutes to obtain a heat-resistant egg yolk liquid.

[0046] Comparative Example 1: Preparation of High-Temperature Resistant Egg Liquid

[0047] The preparation method is the same as in Example 1, except that Comparative Example 1 only undergoes hydrolysis treatment.

[0048] Comparative Example 2: Preparation of High-Temperature Resistant Egg Liquid

[0049] The preparation method is the same as in Example 1, except that only sugar is added in Comparative Example 2.

[0050] Comparative Example 3: Preparation of High-Temperature Resistant Egg Liquid

[0051] The preparation method is the same as in Example 1, except that Comparative Example 3 was subjected to microfluidic homogenization treatment.

[0052] Comparative Example 4: Preparation of High-Temperature Resistant Egg Liquid

[0053] The preparation method is the same as in Example 1, except that Comparative Example 4 is not subjected to hydrolysis.

[0054] Comparative Example 5: Preparation of High-Temperature Resistant Egg Liquid

[0055] The preparation method is the same as in Example 1, except that no sugar is added in Comparative Example 5.

[0056] Comparative Example 6: Preparation of High-Temperature Resistant Egg Liquid

[0057] The preparation method is the same as in Example 1, except that Comparative Example 6 does not undergo microfluidic homogenization treatment.

[0058] Comparative Example 7: Preparation of High-Temperature Resistant Egg Liquid

[0059] The preparation method is the same as in Example 1, except that in Comparative Example 7, erythrose is replaced with sucrose.

[0060] Comparative Example 8: Preparation of High-Temperature Resistant Egg Liquid

[0061] The preparation method is the same as in Example 1, except that in Comparative Example 8, erythritol is replaced with glucose, a hexose sugar.

[0062] Comparative Example 9: Preparation of High-Temperature Resistant Egg Liquid

[0063] The preparation method is the same as in Example 1, except that in Comparative Example 9, erythritol is replaced with tricarbon sugar glyceraldehyde.

[0064] Experimental Example 1: Heat Resistance Test of Egg Liquid

[0065] When egg liquid is heated for sterilization, the proteins in the egg liquid gradually form a gel and produce a fishy smell as the temperature rises. In this experiment, the storage modulus G' was measured as a function of temperature to determine the sterilization temperature at which the egg liquid forms a gel. At the same time, the fishy smell was determined by sensory evaluation, thus obtaining the highest sterilization temperature for the samples of Examples 1-3, Comparative Examples 1-9, and the control group (fresh egg liquid).

[0066] Measurement method:

[0067] ① Determination of the temperature at which egg liquid forms a gel

[0068] A rheometer was used with a dynamic temperature scanning program to determine the change of egg liquid storage modulus G' with temperature. The sample scanning temperature range was selected as 60-85℃, and the heating rate was 1℃ / min.

[0069] ② Determination of the temperature at which the egg liquid produces a fishy smell

[0070] Sensory evaluation was conducted using 15 food professionals with normal sense of smell. The fishy smell of the egg liquid from Examples 1-3, Comparative Examples 1-9, and the control group (fresh egg liquid) was evaluated by smell, and the temperature at which the fishy smell was produced was recorded.

[0071] Measurement results: see Table 1.

[0072] Table 1. Egg liquid forming a gel, producing a fishy smell, and the highest sterilization temperature.

[0073] .

[0074] Results Analysis: Table 1 shows that the highest sterilization temperature for Examples 1-3 was 77-82℃, indicating that the process described in this application can effectively delay the formation of egg liquid gel and the generation of fishy odor, significantly improving the heat resistance of the egg liquid. The experimental data from Example 1, the control group, and Comparative Examples 1-3 show that the heat resistance of the egg liquid in Comparative Examples 1-3 was significantly lower than that in Example 1. However, compared with the control group, protease hydrolysis (Comparative Example 1) and added sugar (Comparative Example 2) can improve the heat resistance of the egg liquid to a certain extent, while dispersion treatment (Comparative Example 3) lowers the temperature at which the egg liquid gels and develops a fishy odor. This may be because dispersion treatment causes protein molecules to unfold and their conformation to change, thus facilitating gel formation and the generation of fishy odor. Based on the experimental data from Comparative Examples 4-6, it can be seen that in Comparative Example 6, protease hydrolysis and added sugar had a synergistic effect. Compared with protease hydrolysis alone (Comparative Example 1) and added sugar alone (Comparative Example 2), its heat resistance was further improved, but the improvement was not significant. The heat resistance of the egg liquid was lower than that of Example 1. This is because the mutual attraction between the protein in the egg liquid and the amino acid molecules produced by hydrolysis makes it more difficult for sugar and protein to fully combine. In Comparative Example 5, the dispersion treatment and protease hydrolysis worked together. The dispersion treatment caused a change in the conformation of the unhydrolyzed protein molecules. Therefore, compared with protease hydrolysis alone (Comparative Example 1), the heat resistance of the egg liquid actually decreased. The heat resistance of Comparative Example 4, which combines dispersion treatment with added sugar, is higher than that of Comparative Example 2 (sugar addition alone). This is because dispersion treatment separates proteins from water molecules, and the small protein particles are more likely to bind with sugar, facilitating the formation of a protective film on the protein surface, thus protecting the protein and improving its heat resistance. However, even though Comparative Examples 4 and 6 show improved heat resistance compared to single techniques, their sterilization temperatures are still lower than those of Example 1. This indicates that only the combined effects of protease hydrolysis, sugar addition, and dispersion treatment can achieve the technical effect of increasing the sterilization temperature of the egg liquid to 77-82℃ as described in this application. Compared to Example 1, Comparative Examples 7 and 8 show lower heat resistance because sucrose and glucose (a hexose) have large molecular weights, making it difficult to form a dense protective film on the protein surface, thus ensuring the structure and function of the protein at high temperatures. Comparative Example 9 uses trioses with smaller molecular weights, and its heat resistance is not significantly different from that of Example 1.

[0075] Experimental Example 2: Shelf Life Determination

[0076] Egg liquids from Examples 1-3, Comparative Examples 1-8, and the control group (fresh egg liquid) were packaged in transparent food bags and sterilized at the highest sterilization temperature of Example 1 for 3 minutes. The sterilized samples were then stored at room temperature (25°C). Microbiological testing was performed on the egg liquids according to the national standard GB 2749-2015 "Eggs and Egg Products" to determine their shelf life.

[0077] Measurement results: see Table 2.

[0078] Table 2 Results of Egg Liquid Shelf Life Determination

[0079] .

[0080] Results Analysis: As shown in Table 2, compared with the control group, the shelf life of the sterilized egg liquid prepared by the process of this application in Examples 1-3 was significantly extended to 25-30 days. The shelf life of Comparative Examples 1-6 was also extended to a certain extent with the increase of sterilization temperature and the enhancement of sterilization effect. Compared with Example 1, Comparative Examples 7 and 8 had significantly shorter shelf lives, but compared with Comparative Example 6, which had the same sterilization temperature, their shelf lives were shorter. Comparative Example 8 also had a shorter shelf life compared with Example 1, which had a similar sterilization temperature. This may be because, compared with other sugars, tetracarbon sugars, pentose sugars, and their sugar alcohols are difficult for microorganisms to utilize quickly. At room temperature, they cannot quickly provide sufficient carbon source and energy for the growth and reproduction of microorganisms, thus effectively improving the stability of the egg liquid at room temperature, and extending the shelf life at the same sterilization temperature.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing high-temperature resistant egg liquid, characterized in that, include: After hydrolyzing the egg liquid with papain, erythrosine is added and the mixture is homogenized by microfluidic jet to obtain a heat-resistant egg liquid. Alternatively, after hydrolyzing the egg liquid with Bacillus subtilis protease, xylitol is added and the mixture is then subjected to colloid milling to obtain heat-resistant egg liquid. Alternatively, after hydrolyzing the egg liquid with flavor protease and aspartic protease, adding erythritol and arabinose and then treating it with a high-voltage electric field, a heat-resistant egg liquid can be obtained. The above-mentioned heat-resistant egg liquid will not form a gel or produce a fishy smell after being sterilized by heating at 77-82℃, and its shelf life can reach 25-30 days at room temperature.

2. A high-temperature resistant egg liquid prepared according to the method of claim 1.

3. An egg product prepared by sterilizing the high-temperature resistant egg liquid as described in claim 2 at high temperature.