Method for regulating and controlling ovalbumin gel performance and application

Abstract

The invention discloses a method for regulating and controlling ovalbumin gel performance and application, and relates to the technical field of methods for regulating and controlling ovalbumin gel performance by using a metal phenol network. Comprising the following steps: S1, preparing an MPN solution: mixing an epigallocatechin gallate solution with a Zn < 2 + > solution, and adjusting the pH value to 7 to obtain an EGCG-Zn < 2 + >-based MPN solution; s2, preparation of an OVM-MPN compound: preparing an ovalbumin solution, adding the EGCG-Zn < 2 + >-based MPN solution into the ovalbumin solution, and adjusting the pH value to 7 to obtain the OVM compound; and S3, preparing gel: heating the OVM compound at 95 DEG C for 10 minutes to obtain the gel. A network structure formed by compounding metal phenol is used for adjusting the performance of ovalbumin, the protein gel with good performance is prepared, the thermal stability and mechanical performance of the gel are improved, the requirements of different application scenes can be met, a universal strategy is explored, and the application prospect is wide. A solution to modulate the properties of protein-based food matrices is provided.

Description

Technical Field

[0001] The present invention relates to the technical field of protein gels, and more particularly to the technical field of methods for regulating the gel properties of ovalbumin using metal-phenol networks. Background Art

[0002] Ovalbumin (OVA), as the main component of egg white protein, is an excellent source of high-quality animal protein, rich in trace minerals such as phosphorus, which is of great significance for maintaining human health. At the same time, its easy separation and purification characteristics make it have potential application value in the fields of food, medicine, biotechnology, etc. However, natural OVA has some obvious defects. More than half of the amino acids in its molecule are hydrophobic amino acids, and one-third are charged residues. This composition leads to strong intramolecular hydrophobic interactions, making OVA prone to extensive aggregation in solution. This aggregation phenomenon not only affects its solubility, but also results in poor functional properties, such as low gel strength and insufficient stability, severely limiting the application of OVA as a functional component in actual production.

[0003] To improve the performance of OVA, researchers have conducted a large number of explorations. It has been found that OVA can bind to tea polyphenols (TP) through covalent and non-covalent interactions. This binding can change the conformation of OVA molecules, enhance their hydration ability, and thus improve the stability of the gel network structure, having a positive impact on the application of OVA in the food industry and biotechnology fields. For example, the antioxidant activity of pure OVA gels is relatively low. In food systems, when OVA binds to TP, the antioxidant capacity of the system is significantly enhanced under different pH conditions. Epigallocatechin gallate (EGCG), as the main component of tea polyphenols, has attracted much attention due to its antioxidant properties and various health benefits. After it binds to OVA, the OVA-EGCG conjugate has fewer α-helices and more β-sheets, which improves the surface hydrophobicity of OVA and reduces the stability of its tertiary structure. These conjugates have better storage stability and lower viscosity. However, despite these advantages, this kind of binding may also have the disadvantage of reducing the nutritional value of OVA.

[0004] In addition, the influence of metal ions on the gel properties of proteins is also very complex. Different concentrations and types of metal ions will significantly affect the aggregation process and cross-linking degree of protein gels. Taking zinc ions as an example, although high-valent zinc ions can change the protein conformation and affect the polymerization and cross-linking of molecular chains, they are not conducive to network formation, resulting in reduced water retention and protein denaturation, making the gel structure fragile. In contrast, divalent zinc ions (Zn 2+ ) can improve the gel hardness, but will form a looser and more irregular gel network. Thus, it can be seen that single metal ion treatment is also difficult to effectively improve the comprehensive performance of OVA gels.

[0005] The Chinese patent with application number CN202410412465.1 discloses an ultra-stretched ovalbumin hydrogel with adjustable mechanical properties and a preparation method thereof. It uses fresh ovalbumin to make the main carrier, and induces the orderly deposition and solidification of the protein inside the ovalbumin to form a hydrogel by adjusting the pH in a purely physical way, which retains the active substances in the ovalbumin that are beneficial to biological activities to the greatest extent. It avoids the introduction of chemical toxic substances by physical gelation. At the same time, its mechanical properties are ultra-stretched and multi-stage adjustable, which is comparable to conventional chemical cross-linked hydrogels. The physically cross-linked hydrogel provided by the patent has a stable hydrogel network formed by non-covalent hydrogen bonds and electrostatic repulsion, and has the properties of self-healing and shear thinning at room temperature. However, the technical solution of the application uses a monovalent alkali metal ion solution in the preparation process, and involves some operations and environments that may not be suitable for food processing, and it cannot guarantee that the final product meets food safety standards. In other words, the hydrogel in the patent is mainly to meet the requirements of biomedicine and other fields for mechanical properties, biocompatibility, etc., and its performance in food in terms of taste and flavor may not be ideal.

[0006] In summary, due to the above-mentioned shortcomings of the current methods for improving the performance of egg white protein gels, the prepared egg white protein gel may obtain good processing characteristics but lose its nutritional value, or cannot be used for food processing. Therefore, developing a method for efficiently and comprehensively improving the performance of egg white protein gels and reducing negative effects has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0007] In view of the current methods for improving the performance of egg white protein gel, it is often impossible to improve its mechanical properties while taking into account the nutritional value. The purpose of the present invention is to provide a method for regulating the performance of egg white protein gel, prepare and utilize a metal-phenol network to modify egg white protein, optimize the structure and functional properties of its gel, and obtain a composite gel that can have both processing performance and nutritional value, thereby solving its limitations in practical applications and providing technical support for the widespread application of egg white protein in the fields of food, biotechnology, etc.

[0008] The technical solution adopted by the present invention to solve its technical problem is:

[0009] A method for regulating the performance of ovalbumin gel, comprising the following steps:

[0010] S1: Preparation of MPN solution: Mix epigallocatechin gallate solution with Zn 2+ The solutions were mixed and stirred to allow the two solutions to contact and react to obtain a first mixed solution, and then the pH value of the first mixed solution was adjusted to 7 to obtain EGCG-Zn 2+ MPN based solution.

[0011] In this application, we combined the epigallocatechin gallate (EGCG) solution with the Zn 2+ solution, and the resulting solution after adjusting the pH value appropriately was called the EGCG-Zn 2+ -based MPN solution, which is usually simply referred to as the MPN solution or directly denoted by MPN. During this process, stirring can accelerate the interaction between EGCG and Zn 2+ . When EGCG and Zn 2+ are used together, a metal-phenolic network can be formed, which synergistically improves the stability and structural integrity of ovalbumin gel. Adjusting the pH value to 7 provides a suitable neutral environment for the subsequent reaction with ovalbumin, which is beneficial to the formation of a stable metal-phenolic network structure.

[0012] Preferably, the concentration of the above epigallocatechin gallate solution is 48 mmol / L, and the concentration of the above Zn 2+ solution is 48 mmol / L, and the two are mixed in a ratio of 1:2 (v / v). Controlling the concentration and addition ratio of the solution can further promote their interaction.

[0013] S2: Preparation of OVA-MPN complex: Take an ovalbumin solution with a concentration of 5% (w / v), that is, the OVA solution, add the above EGCG-Zn 2+ -based MPN solution to the above ovalbumin solution to obtain a second mixed solution, and adjust the pH value of the second mixed solution to 7 to obtain the OVA-MPN complex, that is, the OVM complex. During this process, precisely controlling the concentration of the ovalbumin solution and the reaction conditions can achieve better complexation of OVA and MPN, making the subsequent formed gel structure more dense.

[0014] Preferably, take 50 - 200 μL of the above EGCG-Zn 2+ -based MPN solution and add it to 5 mL of the above ovalbumin solution. As the addition amount of the MPN solution changes, the properties such as the hardness and elasticity of the gel will change. Since EGCG contains -OH groups, it will form hydrogen bonds with the amino groups in OVA, making the OVA structure less stable and its rigidity reduced, and thus the hardness reduced. However, EGCG will also cause more cross-linking sites of OVA to be exposed, and Zn 2+ will coordinate with OVA, further enhancing the cross-linking of Zn 2+ -OVA. Under the synergistic action of the two, the cross-linking density between protein molecules will increase, and the hardness will be significantly enhanced. Therefore, the hardness, elasticity, and resilience of the gel will be affected by various factors such as the concentration of EGCG and Zn 2+ and the degree of cross-linking. Setting the addition amount of MPN can obtain more ideal gel properties.

[0015] S3: Prepare the OVM gel: Heat the above OVM complex, preferably in a water bath at 95 °C for 10 min to obtain the OVM gel, and place the above OVM gel at 4 °C for 1 day.

[0016] The OVM gel obtained in this application is actually a composite modification of MPN and ovalbumin OVA. In essence, it still belongs to ovalbumin-based gel. It is through the gelation process of inducing OVA at high temperature, making protein molecules cross-link to form a gel network. The heating process uses a water bath at 95 °C, which can better maintain temperature stability and avoid the influence of temperature fluctuations on the gelation effect. After obtaining the modified ovalbumin gel and placing it at 4 °C for 1 day, the gel structure endowed with metal-phenol network can be further stabilized and optimized.

[0017] In this application, the metal-phenol network formed by the MPN solution is used to modify ovalbumin (OVA). Between Zn 2+ , EGCG and OVA, a dense interaction will form. On the one hand, this interaction can reduce the average particle size of the particles in the OVA solution, neutralize the charge on the protein surface, reduce the aggregation between particles, and thus enhance the stability of the gel. This is because OVA has a complex three-dimensional structure and multiple functional groups, making it easy to form aggregates of different sizes in the solution, resulting in a wide particle size distribution. And the EGCG and OVA molecules change the conformation of the protein through covalent or non-covalent interactions. Also, the electrostatic repulsion generated by EGCG prevents the aggregation of OVA molecules, reducing the average particle size of OVA and thus reducing the turbidity. At the same time, Zn 2+ can coordinate with the functional groups (such as carboxyl and amino groups) on OVA, change the internal structure of the protein molecules, and form a more ordered arrangement. When EGCG and Zn 2+ act together, more EGCG-Zn 2+ complexes will form, bind to OVA, and can significantly reduce the absolute value of the zeta potential on the surface of OVA (P < 0.05), enhance the interaction between particles, and result in the reduction of the average particle size and turbidity. However, when the dosage of the MPN solution is too high, metal ions will destroy the covalent or non-covalent interactions between OVA and EGCG. Excessive Zn 2+ will shield the negative charge on the surface of OVA, significantly increase the absolute value of the zeta potential (P < 0.05), lead to a reduction in the repulsive force between protein molecules, promote the cross-linking and aggregation of particles, and then the aggregation rate of OVA exceeds its dissociation rate, resulting in an increase in the average particle size.

[0018] On the other hand, Zn 2+, The covalent binding between EGCG and OVA increases the thermal denaturation temperature of OVA, enabling the gel to maintain a stable structure at higher temperatures. This is because EGCG covalently binds to OVA through a free radical reaction, increasing the molecular weight and stabilizing the structure of OVA. Meanwhile, Zn 2+ can coordinate with the amino and hydroxyl groups on the surface of OVA, weakening the hydrogen bond interaction between OVA molecules. When the concentration of the MPN solution is further increased, more Zn 2+ ions bind to OVA, forming a more compact complex structure. However, when Zn 2+ is in excess, it will disrupt the covalent or non-covalent interactions between OVA and EGCG, shield the negative charges on the surface of OVA, increase the absolute value of the zeta potential, resulting in a decrease in the repulsive force between protein molecules, promoting the cross-linking and aggregation of particles, and significantly increasing the average particle size, which is not conducive to the improvement of gel properties. EGCG binds to OVA through hydrogen bonds, further weakening the intermolecular forces, enhancing the local order of OVA molecules, and enhancing its thermal stability. In addition, the hydrophobic interaction between EGCG and the hydrophilic groups on the surface of OVA enhances the overall structural stability of OVA.

[0019] In terms of chemical structure, the proportion of C-O interactions in the ovalbumin gel increases, while the proportion of C=O interactions decreases. This is due to the change of chemical bonds within and between protein molecules caused by MPN polymerization, thereby enhancing the crystallinity of the gel. Due to the covalent binding of OVA and EGCG, the carbonyl group of EGCG reacts with the amino group or other functional groups in OVA to form new C=O bonds. The addition of Zn 2+ can coordinate with the oxygen atom in the C=O group to form a stable complex. In addition, Zn 2+ can promote the aggregation of OVA-EGCG, further reducing the number of C=O groups.

[0020] In terms of water distribution, the addition of MPN affects the hydrogen bond network, resulting in a decrease in strongly bound water. By balancing the bound water state and free water state to regulate the water distribution, it directly affects the texture properties of the gel. In addition, with the increase in the MPN content, a more obvious dense network structure will be formed, reducing thermal fluctuations and increasing the elastic modulus of the ovalbumin gel, further enhancing the stability and elasticity of the gel.

[0021] The method of the present invention can effectively improve multiple performance indexes of ovalbumin gel, and the obtained OVM gel also has improved hardness and crystallinity. The maximum hardness can reach 129.72 g after testing, making the gel more ductile and plastic in practical applications. The enhanced thermal stability expands the application range of the gel in high-temperature environments. The increase in elastic modulus improves the elasticity of the gel, enabling it to better adapt to external pressure changes. The optimization of the microstructure, which becomes more compact and dense, helps to improve the stability and uniformity of the gel and enhance the product quality. Secondly, by systematically studying the mechanism of the effect of MPN on the performance of ovalbumin gel, the present invention provides a solid theoretical basis for precisely controlling the quality of ovalbumin. At the same time, the developed simple and effective regulation method provides a reliable technical means for the controllable preparation of ovalbumin gel, contributing to promoting technological innovation and industrial development in related fields. Finally, the optimized ovalbumin gel of the present invention shows broader application prospects in fields such as the food industry and biotechnology. In the food industry, it can be used to prepare various high-quality food gel products, such as improving the texture and taste of pastries, jellies, etc., and extending the shelf life of foods; in the field of biotechnology, it can be used as a biomaterial for tissue engineering, drug release, etc., providing new options for biomedical research and applications.

[0022] Compared with the prior art, the technical solution of the present application has at least the following beneficial effects:

[0023] 1. The present invention uses an EGCG solution and a Zn 2+ solution to modify ovalbumin OVA, and controls the pH value of the solution during the process, effectively preparing a modified OVM gel. An obvious metal-phenol dense network structure is formed on the gel surface, improving the thermal stability and mechanical properties of the gel, enabling it to be better used in production and processing, and meeting the requirements of different application scenarios.

[0024] 2. The present invention explores a general strategy for modifying ovalbumin-based gels. By controlling conditions such as the addition amount, concentration, and ratio of EGCG and Zn 2+ , a modified protein gel is prepared, regulating the water distribution and microstructure of the gel, improving its texture and appearance, and providing a solution with adjustable characteristics for protein-based food matrices. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments and comparative examples. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0026] Figure 1 This is a color comparison chart of the gels prepared in the comparative examples and examples of the present invention.

[0027] Figure 2 This is the SEM micrograph of the gel of Comparative Example 1 of the present invention.

[0028] Figure 3 This is the SEM micrograph of the gel of Comparative Example 2 of the present invention.

[0029] Figure 4 This is the SEM micrograph of the OVM gel of Example 1 of the present invention.

[0030] Figure 5 This is the SEM micrograph of the OVM gel of Example 2 of the present invention.

[0031] Figure 6 This is the SEM micrograph of the OVM gel of Example 3 of the present invention.

[0032] Figure 7 This is the SEM micrograph of the OVM gel of Example 4 of the present invention. Detailed implementation manners

[0033] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0034] A method for regulating the properties of ovalbumin gel, comprising the following steps:

[0035] S1: Prepare an MPN solution: Mix a 48 mmol / L epigallocatechin gallate (EGCG) solution and a 48 mmol / L Zn 2+ solution in a ratio of 1:2 (v / v), stir to allow the two solutions to react in contact, obtain a first mixed solution, and then adjust the pH value of the above first mixed solution to 7 to obtain an EGCG-Zn 2+ -based MPN solution.

[0036] S2: Prepare an OVA-MPN complex: Prepare an ovalbumin (OVA) solution with a concentration of 5% (w / v), that is, an OVA solution. Take 50 - 200 μL of the above EGCG-Zn 2+ -based MPN solution and add it to 5 mL of the above OVA solution to obtain a second mixed solution, and adjust the pH value of the above second mixed solution to 7 to obtain an OVA-MPN (OVM) complex.

[0037] S3: Prepare the OVM gel: Heat the above OVM complex in a water bath at 95 °C for 10 min to obtain the OVM gel, and place the above OVM gel at 4 °C for 1 day.

[0038] It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to specific embodiments.

[0039] Examples and comparative examples

[0040] Material preparation: OVA was purchased from Aladdin Biochemical Technology Co., Ltd. (Shanghai, China), zinc chloride (Zn 2+ ) was purchased from Damao Chemical Reagent Factory (Tianjin, China), and EGCG was purchased from Shanghai Yuanye Bio-Technology Co., Ltd. Other chemicals were all of analytical grade and were further purified before use to ensure the accuracy and reliability of experimental results. When selecting raw material suppliers, their product quality and stability were fully considered, and strict quality inspections were carried out on each batch of raw materials to ensure that they met the experimental requirements.

[0041] Experimental procedure: S1: Prepare the MPN solution: Accurately measure 48 mmol / L EGCG solution and 48 mmol / L Zn 2+ solution, usually ZnCl2 solution, and slowly mix them in a clean container at a ratio of 1:2 (v / v). Use a magnetic stirrer to quickly stir the solution at a relatively high speed (such as 1000 r / min) for 5 - 10 min to make the two solutions fully mixed and uniform. During the stirring process, slowly add dilute hydrochloric acid or dilute sodium hydroxide solution drop by drop, and at the same time use a pH meter to monitor the pH value of the solution in real time and precisely adjust it to 7.0. After stirring, obtain a uniform EGCG-Zn 2+ -based MPN solution for standby. In this step, strictly control the concentration, volume ratio, and pH value of the solution to ensure the quality stability of the MPN solution.

[0042] S2: Prepare the OVA-MPN complex: Weigh an appropriate amount of OVA powder, add an appropriate amount of deionized water, stir and dissolve it to prepare an OVA solution with a concentration of 5% (w / v). Measure four portions of 5 mL OVA solution into clean containers, and then add 50, 100, 150, and 200 μL of MPN solution respectively, and gently stir to make the solution mixed and uniform. Use a pH regulator (such as dilute hydrochloric acid or dilute sodium hydroxide solution) to precisely adjust the pH value of the mixed solution to 7.0 to form an OVA-MPN (OVM) complex.

[0043] S3: Prepare the OVM gel: Place the container containing the OVM complex in a constant temperature water bath at 95 °C and heat for 10 min. During the heating process, keep the temperature of the water bath stable to avoid the influence of temperature fluctuations on the gelation effect. After heating is completed, take out the container and place it in a refrigerator at 4 °C for 1 day to fully stabilize the gel structure of the OVM gel.

[0044] Before subsequent measurements, take the sample out of the refrigerator and place it in an environment at 25 °C for a period of time to reach an equilibrium state. During the entire preparation process, strictly control each operation link to ensure the consistency and repeatability of the experimental conditions.

[0045] The experimental processes of the comparative examples and examples of the present invention were all carried out according to the above technical solutions, and the difference was only in adjusting the concentration, feeding amount, etc. of relevant reagents. The specific implementation situations are shown in Table 1 below:

[0046] Table 1 Specific implementation situations of examples and comparative examples

[0047]

[0048] Relevant performance test: Take the gels prepared in the examples and comparative examples, cut them into small pieces of 1 cm 3 , and then manually place them on the platform of the texture analyzer. Use a cylindrical compression probe with a diameter of 36 mm to compress each sample to half of its original height. The speeds before testing, during testing, and after testing are set to 1 mm / s, 1 mm / s, and 5 mm / s respectively, and the interval time is 5 s. The hardness, elasticity, and resilience values can be analyzed through software (Micro Stable software). The results are shown in Table 2.

[0049] Table 2 Texture properties of the gels prepared in the examples and comparative examples

[0050]

[0051]

[0052] The texture changes of the gels are shown in Table 2. It can be seen that compared with the pure OVA gel, the hardness of the gel modified with EGCG decreased significantly from 78.27 g to 61.95 g, and there was no significant difference in elasticity and resilience. As the concentrations of EGCG and ZnCl2 increased, the hardness of the gel increased significantly, the elasticity first decreased significantly from 0.44% to 0.3%, and then increased significantly to 0.39%, while the resilience increased from 0.11 to 0.24 significantly and then showed no obvious difference, indicating that the addition of EGCG and Zn 2+ showed good modification of the gel.

[0053] Afterwards, a color difference meter was used to measure the color of the obtained gel. Among them, L is the brightness, and its value from 0 to 100 represents pure black to pure white; the a value represents green to red from small to large; the b value represents blue to yellow from small to large. The average value of four points was taken for each sample, and the results are shown in Table 3 and Figure 1 as shown, Figure 1 from left to right are the gels prepared in Comparative Example 1, Comparative Example 2, Example 1, Example 2, Example 3 and Example 4.

[0054] Table 3 Colors of gels prepared in examples and comparative examples

[0055] Group L value a value b value Comparative Example 1 <![CDATA[82.25±2.01 b > <![CDATA[2.83±0.09 a > <![CDATA[6.94±0.33 bc > Comparative Example 2 <![CDATA[88.05±0.77 a > <![CDATA[-0.40±0.12 d > <![CDATA[8.91±0.79 a <!-- 6 -->]]> Example 1 <![CDATA[84.79±0.96 ab > <![CDATA[1.19±0.11 c > <![CDATA[7.87±0.16 ab > Example 2 <![CDATA[83.23±1.31 b > <![CDATA[1.89±0.03 b > <![CDATA[6.32±0.23 c > Example 3 <![CDATA[82.69±0.97 b > <![CDATA[1.99±0.23 b > <![CDATA[5.92±0.41 c > Example 4 <![CDATA[82.47±1.40 b > <![CDATA[1.73±0.21 b > <![CDATA[5.95±0.02 c >

[0056] Color is one of the important indicators for evaluating the sensory properties of OVM gels. The gel color parameters of each treatment group are shown in Table 3. The results show that the a value of the pure OVA gel is negative, while that of the gel added with EGCG or MPN becomes positive, and the red color of the sample deepens, indicating an obvious difference in color between the pure OVA gel and the gel added with EGCG or MPN. The interactions between EGCG and OVA include hydrogen bonds, hydrophobic interactions and electrostatic interactions, all of which can change the conformation of OVA molecules, thereby changing the color of OVA gels. In OVA added with EGCG, L and b are significantly lower than those of pure OVA, and with the increase in the concentration of MPN, the values of L and b show a decreasing trend, indicating that the yellow color of OVA becomes lighter and the brightness value decreases. EGCG and OVA can form an EGCG-OVA complex through covalent bonding, directly affecting the structure of OVA and changing its brightness and color. However, with the increase in the concentration of MPN, the covalent binding of EGCG and OVA is promoted, and the color of EGCG itself becomes more significant, showing a light yellow color. At the same time, Zn 2+ may form a complex with EGCG or OVA, changing the spatial conformation of OVA, thereby affecting the color change. As Figure 1 can be seen, the OVA gel prepared without MPN solution in Comparative Example 2 is yellow, and the gel added with EGCG is reddish. The apparent colors of the OVM gels added with different amounts of MPN in Examples 1-4 are light red or light yellow, with low brightness, which is consistent with the color results in Table 3. The color is less affected by EGCG and is relatively stable without obvious changes.

[0057] The microstructure of the gel is as Figures 2 - 7 shown, Figures 2 - 7 successively the SEM micrographs of the gels prepared in Comparative Examples 1-2 and Examples 1-4. As Figures 2 - 7It can be seen that the microstructures of all gels present a three-dimensional network structure, showing good structural properties. When only EGCG was added in Comparative Example 1, the microstructure of the gel tended to be rough and irregular, with more cavity structures. In the OVA-MPN gels of Examples 1 to 4, the movement of OVA molecules after heating led to their aggregation, and the microstructure was denser and more compact, which was related to the synergistic promotion of the cross-linking reaction by EGCG and Zn 2+ and the enhancement of intermolecular interactions. With the increase in the addition amount of MPN, the connection thickness of the "walls" weakened, and more small pore structures were formed in the "walls" of the voids, indicating that the -OH in EGCG and the hydrogen bonds in OVA combined to form a rich void-wall-void structure. Therefore, it can be concluded that the change in the protein microstructure will lead to the change in the physical properties of OVA. Combining with the results of texture analysis, divalent metal Zn 2+ has a supporting wall connection function, enhancing the hardness and resilience of the OVA gel, which is consistent with the SEM results, indicating that the use of EGCG and Zn 2+ to form a network structure for the composite modification of the OVA gel is reasonable and effective.

[0058] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

Claims

1. A method for regulating the gel properties of ovalbumin, characterized in that, It includes the following steps: S1: Prepare the MPN solution: Mix the epigallocatechin gallate solution with the Zn 2+ solution, stir to allow the two solutions to react in contact, obtain a first mixed solution, and then adjust the pH value of the first mixed solution to 7 to obtain the EGCG-Zn 2+ -based MPN solution; S2: Preparation of OVA-MPN complex: Take an ovalbumin solution with a concentration of 5% (w / v), and add the EGCG-Zn 2+ -based MPN solution thereto to obtain a second mixed solution, and adjust the pH value of the second mixed solution to 7 to obtain an OVA-MPN complex, that is, an OVM complex; S3: Prepare OVM gel: Heat the OVM complex to obtain OVM gel, and place the OVM gel at 4°C for 1 day.

2. A method for regulating the properties of ovalbumin gel according to claim 1, characterized in that, In S1, the concentration of the epigallocatechin gallate solution is 48 mmol / L, and the concentration of the Zn 2+ solution is 48 mmol / L.

3. A method for regulating the properties of ovalbumin gel according to claim 2, characterized in that, In S1, the epigallocatechin gallate solution and the Zn 2+ solution are mixed in a ratio of 1:2 (v / v).

4. A method for regulating the properties of ovalbumin gel according to claim 1, characterized in that, In S2, 50 - 200 μL of the EGCG-Zn 2+ -based MPN solution is added to 5 mL of the ovalbumin solution.

5. A method for regulating the properties of ovalbumin gel according to claim 1, characterized in that, In the said S3, heat the OVM complex in a water bath at 95°C for 10 min to obtain OVM gel.

6. Application of a method for regulating the gel properties of ovalbumin, characterized in that, Use the method for regulating the properties of ovalbumin gel according to any one of claims 1 to 5 to prepare ovalbumin-based gel.

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