Preparation method of low-viscosity high-temperature-resistant egg white liquid
Through the ultrasonic/pH collaborative treatment method, the problem of denaturation and coagulation of fresh egg white during the hot processing process is solved, and its thermal stability is significantly improved, achieving low viscosity and high temperature resistant egg white liquid preparation.
Patent Information
- Application Number
- CN202510013682.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-06
- Publication Date
- 2025-03-14
AI Technical Summary
Fresh egg whites are prone to denaturation and condensation during hot processing, resulting in poor thermal stability and limiting their processing applicability in downstream industries.
Ultrasonic/pH collaborative treatment method is adopted to depolymerize egg mucin by sonication, reducing the viscosity of liquid egg whites, and controlling the electrostatic interaction of lysozyme through pH regulation, thereby regulating the electrostatic interaction of egg white proteins and improving thermal stability.
After heating at 56-72°C for 5 minutes, the turbidity dropped significantly, the content of soluble protein increased significantly, and the gel point rose from 63°C to 76.5°C, which significantly improved the thermal stability of fresh egg white.
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Figure CN119605972A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for preparing a low-viscosity and high-temperature resistant egg white liquid, and in particular to a method for preparing a low-viscosity and high-temperature resistant egg white liquid by utilizing ultrasound / pH coordinated treatment. Background Art
[0002] China is the world's largest producer and consumer of poultry eggs. However, due to the immaturity of modern processing technology, domestic consumption is still dominated by fresh eggs, and the egg processing rate (the domestic egg processing rate is only 3%) is still far behind that of advanced countries (33% in the United States and 50% in Japan). Various types of egg products can effectively solve the inconvenience of eggshells in transportation and storage. Therefore, nutritious and portable high-end ingredients of egg products represented by special liquid eggs and egg powder are increasingly widely used in Western catering, baking and other industries. However, as a molecular crowded system with highly enriched protein and diverse protein composition, fresh egg white is very prone to denaturation and coagulation during thermal processing, resulting in thermal instability of the system, which seriously restricts the processing applicability of egg white protein raw materials in downstream industries.
[0003] For a long time, the disordered aggregation caused by the high viscosity and high protein concentration of fresh egg white has been the "bottleneck" problem that leads to the poor thermal stability of fresh egg white. If the thermal stability of fresh egg white can be improved by controlling the key proteins in fresh egg white, the targeting of regulation can be effectively increased. According to the literature, ovomucin, as the protein with the highest degree of glycosylation in egg white protein, forms a weakly cross-linked gel network at room temperature and is the main contributor to the high viscosity of fresh egg white. As the thermal processing proceeds, ovomucin undergoes self-crosslinking and co-crosslinking with other proteins to form the initial skeleton of egg white gel. Lysozyme is the only positively charged protein in fresh egg white. During the thermal processing, it will undergo severe co-aggregation behavior with other proteins driven by electrostatic interactions and is the main participant in the disordered aggregation of egg white protein during heating. At the same time, controlling ovomucin and lysozyme will inhibit the increase of turbidity of fresh egg white during heating, and the transition process from fluid to semi-solid / solid gel, effectively improving the thermal stability of fresh egg white, and providing a theoretical basis for the preparation of low-viscosity and high-temperature resistant egg white liquid.
[0004] At present, the existing high temperature resistant egg liquid and preparation method are to use protease (papain, bromelain, flavor protease, trypsin, pepsin, cathepsin, subtilisin, aspartic protease one or more) to hydrolyze the egg white liquid, and then add tetrasaccharides and their sugar alcohols (erythrose, thulose, erythritol) or pentose and their sugar alcohols (xylose, arabinose, ribose, xylitol) to the egg liquid, and finally disperse the egg liquid (microjet homogenization, ultrasonic treatment, colloid mill treatment, high shear emulsification treatment, high voltage electric field treatment One or more). The operation steps of this method are extremely cumbersome, and a large amount of additives are added exogenously, which is not suitable for large-scale industrial production. Therefore, a method for preparing a low-viscosity and high-temperature resistant egg white liquid that is efficient, convenient, environmentally friendly, and simple to operate is proposed, which is to improve the processing applicability of egg white protein as a raw material in downstream industries. Provide a theoretical basis, provide technical support for the development of heat-resistant protein ingredients, and provide new strategies for the extension of the chain value-added and high-quality development of my country's egg processing industry.
[0005] Generally speaking, methods to improve the thermal stability of proteins include physical techniques (reducing particle size, homogenization, ultrasound), chemical techniques (glycosylation, phosphorylation) and enzyme modification techniques (enzyme cross-linking and enzyme hydrolysis). As a traditional non-thermal processing physical means, ultrasonic technology has been widely used in food processing due to its high efficiency, convenience and greenness. Generally, the cavitation effect and microjet effect of ultrasound are used to modify protein structure, regulate the interaction of protein components (particle size, protein dispersibility) and improve the processing characteristics of protein (gelation, solubility, foaming and emulsification properties). In addition, the pH adjustment method is a chemical modification method that regulates the electrostatic repulsion between and within protein molecules by changing the surface charge distribution of the protein, thereby changing the protein structure, and this method has less damage to the nutritional value of the protein. Commonly used acid and alkali solutions can be used as processing aids in food production, and the operation process is simple, the parameters are easy to control, and there is no need to rely on expensive equipment.
[0006] The present invention first utilizes the cavitation effect and microfluidic effect of ultrasound to depolymerize the ovomucin in the fresh egg white to reduce the viscosity of the liquid egg white, and uses the pH adjustment method to control the pH value near the isoelectric point of the key protein lysozyme, thereby avoiding the interaction between the lysozyme and other negatively charged proteins in the system, thereby regulating the electrostatic interaction between the components of the egg white protein, and finally achieving the purpose of improving the thermal stability of the fresh egg white. The method is not only efficient and convenient, environmentally friendly, but also simple to operate, and improves the processing efficiency. Summary of the invention
[0007] In order to solve the above technical problems, the present invention provides a method for preparing a low-viscosity and high-temperature resistant egg white liquid by using ultrasonic / pH synergistic treatment to improve the thermal stability of fresh egg white. After the low-viscosity and high-temperature resistant egg white liquid is heated at 56-72°C for 5 minutes, the turbidity decreases significantly and the soluble protein content increases significantly. It can still maintain a fluid state after heating at 72°C for 5 minutes, and the turbidity value decreases from 1.87±0.58 to 0.38±0.01, the protein concentration increases from 28.9±8.59mg / mL to 96.74±2.70mg / mL, and its gel point increases from 63°C to 76.5°C.
[0008] The technical solution of the present invention is as follows:
[0009] Step 1: Pre-treatment of eggs: Select clean and fresh eggs, separate the eggs from the shells to obtain fresh egg white liquid;
[0010] Step 2, ultrasonic treatment: use an ultrasonic pulverizer to ultrasonically treat the fresh egg white liquid;
[0011] Step 3: pH adjustment: adjust the pH to 10.6;
[0012] Step 4: Pack the product to obtain the finished product;
[0013] In the step 1, the eggs are cleaned and disinfected before the shells are separated.
[0014] In the step 2, the ultrasonic power is 270 W, the ultrasonic time is 10 min, and the ultrasonic treatment and interval time are both set to 3 s.
[0015] For step three, first use 0.1M NaOH to adjust the pH value of fresh egg white to about 10.0, and then use 0.01M NaOH solution to adjust the pH value of fresh egg white to about 10.6.
[0016] The preparation principle of the present invention is as follows:
[0017] The invention first separates eggs from shells, then ultrasonically treats the separated egg white liquid, subsequently adjusts the pH value of the ultrasonically treated egg liquid, and finally packages the product to obtain a low-viscosity, high-temperature-resistant egg white liquid.
[0018] The preparation process of the invention is as follows: separation of eggs from shells, ultrasonic treatment, pH value adjustment and packaging.
[0019] The beneficial effects of the present invention are:
[0020] 1. The present invention adopts an ultrasonic / pH synergistic treatment method to depolymerize ovomucin in egg white protein by ultrasonic treatment, thereby increasing the fluidity of fresh egg white; and controls lysozyme, the only positively charged protein in the egg white protein system, by a pH adjustment method, thereby adjusting the electrostatic interaction between lysozyme and other egg white proteins, thereby improving the thermal stability of fresh egg white, reducing the degree of damage to the protein, and effectively protecting the nutritional components of the egg white protein.
[0021] 2. The present invention proposes a method for preparing low-viscosity and high-temperature resistant egg white liquid that is efficient, convenient, environmentally friendly, and easy to operate, which provides a theoretical basis for improving the processing applicability of egg white protein as a raw material in downstream industries, provides technical support for the development of low-viscosity and high-temperature resistant egg white liquid ingredients, and provides a new strategy for chain extension, value-added, and high-quality development of my country's egg processing industry.
[0022] 3. Compared with untreated fresh egg white, after heating at 56-72℃ for 5 minutes, the turbidity of the low-viscosity and high-temperature-resistant egg white solution decreased significantly, while the soluble protein content increased significantly. At the same time, its gel point increased from 63℃ to 76.5℃.
[0023] Compared with the prior art, the present invention has the following beneficial effects:
[0024] Compared with the traditional methods of using physical modification, chemical modification and enzymatic modification alone to improve the thermal stability of proteins, the preparation process of the present invention is green and safe, the operation process is simple, the parameters are easy to control, and there is no need to rely on expensive equipment. It can effectively reduce energy consumption in large-scale production processes and thus reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 The gel electrophoresis results of Example 1, Example 2, Example 3 and Example 4 before and after heating are shown; (EW: fresh egg white; pH-EW: heat-resistant egg white liquid prepared only by pH adjustment; UEW: heat-resistant egg white liquid prepared only by ultrasonic treatment; US-pH10 EW: low-viscosity, high-temperature-resistant egg white liquid prepared by combined ultrasonic / pH adjustment treatment).
[0026] Figure 2 The following are the actual pictures of Example 1, Example 2, Example 3 and Example 4 before and after heating; (EW: fresh egg white; US-pH10 EW: low-viscosity and high-temperature-resistant egg white liquid prepared by combined ultrasound / pH adjustment treatment).
[0027] Figure 3The turbidity of the samples before and after heating in Example 1, Example 2, Example 3 and Example 4; (EW: fresh egg white; pH-EW: heat-resistant egg white liquid prepared only by pH adjustment; UEW: heat-resistant egg white liquid prepared only by ultrasonic treatment; US-pH10 EW: low-viscosity, high-temperature-resistant egg white liquid prepared by combined ultrasonic / pH adjustment treatment).
[0028] Figure 4 is the concentration of soluble protein in the supernatant of Example 1, Example 2, Example 3 and Example 4; (EW: fresh egg white; pH-EW: heat-resistant egg white liquid prepared only by pH adjustment; UEW: heat-resistant egg white liquid prepared only by ultrasonic treatment; US-pH10 EW: low-viscosity, high-temperature-resistant egg white liquid prepared by combined ultrasonic / pH adjustment treatment).
[0029] Figure 5 The viscosity scanning results of Example 1, Example 2, Example 3 and Example 4; (EW: fresh egg white; pH-EW: heat-resistant egg white liquid prepared by pH adjustment only; UEW: heat-resistant egg white liquid prepared by ultrasonic treatment only; US-pH10 EW: low-viscosity, high-temperature-resistant egg white liquid prepared by combined ultrasonic / pH adjustment treatment).
[0030] Figure 6 The gel formation temperature scanning results of Example 1, Example 2, Example 3 and Example 4 are shown in FIG. 1 , (EW: fresh egg white; pH-EW: heat-resistant egg white liquid prepared by pH adjustment only; UEW: heat-resistant egg white liquid prepared by ultrasonic treatment only; US-pH10 EW: low-viscosity, high-temperature-resistant egg white liquid prepared by combined ultrasonic / pH adjustment treatment). DETAILED DESCRIPTION
[0031] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods.
[0032] Example 1: Preparation of low-viscosity, high-temperature resistant egg white liquid
[0033] Step 1: Select clean and fresh eggs and separate the eggs from the shells to obtain fresh egg white liquid;
[0034] Step 2: The fresh egg white was ultrasonically treated at 270 W ultrasonic power for 10 min, and the ultrasonic treatment and interval time were both set to 3 s;
[0035] Step 3: Use 0.1M NaOH to adjust the pH value of fresh egg white to about 10.0, and then use 0.01M NaOH solution to adjust the pH value of fresh egg white to about 10.6.
[0036] Step 4: Pack the product to obtain the finished product;
[0037] Example 2: Preparation of heat-resistant egg white liquid
[0038] Step 1: Select clean and fresh eggs and separate the eggs from the shells to obtain fresh egg white liquid;
[0039] Step 2: The fresh egg white was ultrasonically treated at 270 W ultrasonic power for 10 min, and the ultrasonic treatment and interval time were both set to 3 s;
[0040] Step 3: Packing the product to obtain the finished product;
[0041] Example 3: Preparation of heat-resistant egg white liquid
[0042] Step 1: Select clean and fresh eggs and separate the eggs from the shells to obtain fresh egg white liquid;
[0043] Step 2: Use 0.1M NaOH to adjust the pH value of fresh egg white to about 10.0, and then use 0.01M NaOH solution to adjust the pH value of fresh egg white to about 10.6.
[0044] Step 3: Packing the product to obtain the finished product;
[0045] Example 4: Preparation of egg white liquid
[0046] Step 1: Select clean and fresh eggs and separate the eggs from the shells to obtain fresh egg white liquid;
[0047] Step 2: Packing the product to obtain the finished product;
[0048]
Measurement method
[0049] 1. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis
[0050] The concentrations of the concentrated gel and the separation gel were 5% and 15%, respectively. After the sample solution was centrifuged at 8000rpm for 10min, the supernatant and the precipitate were quickly separated. The supernatant was diluted 150 times and mixed with the reduced protein loading buffer, boiled at 100℃ for 5min, and 15μL was loaded into each well. The initial concentrated gel voltage was set to 80V. After 30min, the protein completely entered the separation gel, and then 120V electrophoresis was used for 90min. After the electrophoresis was completed, it was stained in Coomassie Brilliant Blue dye for 30min, and then decolorized in distilled water until the bands were clear and without background color. The electrophoresis results were displayed and analyzed by the gel image analysis system.
[0051] 2. Turbidity determination:
[0052] 1 mL of sample solution of each embodiment, comparative example and control group was taken and heated at 56-72° C. for 5 min in a water bath. The heated samples were placed in an ultraviolet spectrophotometer dish with an optical path length of 1 cm. The absorbance of the samples at 600 nm was measured using an ultraviolet spectrophotometer. All measurement processes were repeated three times. The final results were analyzed using the SPSS17 system, with a significance of p<0.05.
[0053] 3. Determination of supernatant protein concentration:
[0054] Take 1 mL of sample solution from each example, comparative example, and control group, heat at 56-72°C for 5 minutes in a water bath, and centrifuge the heated sample at 8000×g for 15 minutes. Take the supernatant, add 20 μL of the supernatant to 200 μL of BCA working solution (50 volumes of BCA working solution A and 1 volume of BCA working solution B). Calculate the protein content in the sample relative to the protein standard. All determination processes were repeated three times. The final results were analyzed using the SPSS17 system, with a significance of p<0.05
[0055] 4. Viscosity scans of different embodiments and comparative examples:
[0056] Take 1 mL of sample solution from each of the examples, comparative examples and control group, heat them in a water bath at 56-72°C for 5 minutes, place the heated samples on the sample plate of the rotational rheometer, set the gap to 1 mm, remove excess sample with a scraper, and set the stabilization time to 120 seconds. Scan for 0.01 seconds at 25°C -1 To 100s -1 Viscosity curves under shear rate.
[0057] 5. Gel formation temperature scans of different embodiments and comparative examples:
[0058] 1 mL of each sample solution of the embodiment, comparative example and control group was placed on the sample plate of the rotational rheometer, the gap was set to 1 mm, and the excess sample was removed with a scraper. A thin layer of silicone oil was covered around the sample to prevent the sample from evaporating during heating. A strain of 1% was applied and the oscillation frequency was set to 1 Hz. The sample was heated from 30°C to 90°C at a rate of 4°C / min, and the storage modulus G' of the sample was measured as a function of temperature, and the gel point of the sample was determined accordingly.
[0059] Summary of main results
[0060] Table 1 Example 1 Results Summary
[0061]
[0062]
[0063] Table 2 Example 2 Results Summary
[0064]
[0065] Table 3 Example 3 Results Summary
[0066]
[0067] Table 4 Example 4 Results Summary
[0068]
[0069] Results Summary
[0070] Figure 1 It was confirmed that the key proteins in fresh egg white are ovomucin and lysozyme, so the thermal stability of fresh egg white can be effectively improved under the condition of controlling both at the same time. Figure 2 to Figure 6 It can be seen that after heating at 56-72°C for 5 minutes, the turbidity of Example 1 (low-viscosity, high-temperature-resistant egg white liquid) is significantly reduced compared with Example 4 (egg white liquid), and the soluble protein content is significantly increased. After heating at 72°C for 5 minutes, the fluid state can still be maintained, and the turbidity value decreases from 1.87±0.58 to 0.38±0.01, the protein concentration increases from 28.9±8.59 mg / mL to 96.74±2.70 mg / mL (the increase ratio is 234.74%), and the gel point increases from 63°C to 76.5°C. Therefore, ultrasound / pH synergistic treatment is an effective method for preparing low-viscosity, high-temperature-resistant egg white liquid.
Claims
1. A method for preparing a low-viscosity, high-temperature-resistant egg white liquid, characterized in that: The preparation method is as follows: Step 1: Pre-treatment of eggs: Select clean and fresh eggs, separate the eggs from the shells to obtain fresh egg white liquid; Step 2, ultrasonic treatment: use an ultrasonic pulverizer to ultrasonically treat the fresh egg white liquid; Step 3: pH adjustment: adjust the pH to 10.6; Step 4: Pack the product to obtain the finished product.
2. The method for preparing a low-viscosity, high-temperature-resistant egg white liquid according to claim 1, characterized in that: In the step 1, the eggs are cleaned and disinfected before the shells are separated.
3. The method for preparing a low-viscosity, high-temperature-resistant egg white liquid according to claim 1, characterized in that: In the step 2, the ultrasonic power is 270 W, the ultrasonic time is 10 min, and the ultrasonic treatment and interval time are both set to 3 s.
4. The method for preparing a low-viscosity, high-temperature-resistant egg white liquid according to claim 1, characterized in that: In the step three, the pH value of the fresh egg white is first adjusted to 10.0 using 0.1M NaOH, and then the pH value of the fresh egg white is adjusted to 10.6 using 0.01M NaOH solution.
5. The method for preparing a low-viscosity, high-temperature-resistant egg white liquid according to claim 1, characterized in that: Compared with untreated fresh egg white, after heating at 56-72°C for 5 minutes, the turbidity of the low-viscosity, high-temperature-resistant egg white liquid decreased significantly, while the soluble protein content increased significantly; it can still maintain a fluid state after heating at 72°C for 5 minutes, and the turbidity value decreased from 1.87±0.58 to 0.38±0.01, the protein concentration increased from 28.9±8.59 mg / mL to 96.74±2.70 mg / mL, and its gel point increased from 63°C to 76.5°C.