Preparation method and application of aqueous solution containing myofibrillar protein

Abstract

The invention provides a preparation method of an aqueous solution containing myofibrillar protein, which comprises the following steps: extracting myofibrillar protein from pork, uniformly dispersing the myofibrillar protein in water, homogenizing to obtain a myofibrillar protein suspension, mixing the myofibrillar protein suspension with L-glutamic acid to obtain a mixed solution, adding glucan, and carrying out glycosylation reaction to obtain the aqueous solution containing the myofibrillar protein. And storing at 4 DEG C to obtain the aqueous solution containing the myofibrillar protein. The invention further provides application. The prepared aqueous solution containing the myofibrillar protein can inhibit the self-assembly behavior of the myofibrillar protein and improve the solubility of the myofibrillar protein in a low-salt system. According to the preparation method disclosed by the invention, through the synergistic effect of L-glutamic acid and glycosylation, the hydrophilicity, electrostatic repulsion and steric hindrance effect of the myofibrillar protein are enhanced, the self-assembly behavior of the myofibrillar protein in a low-salt system is inhibited, and the problem of poor solubility of an aqueous solution containing the myofibrillar protein is solved; the solubility and dispersion stability of an aqueous solution containing myofibrillar protein are enhanced, and technical support is provided for development of meat products.

Description

Technical Field

[0001] This invention belongs to the field of myofibrillar protein preparation technology, specifically relating to a method for preparing an aqueous solution containing myofibrillar protein and its application. Background Technology

[0002] Meat protein, as a complete protein, is recognized as a high-quality source of nutrition. It contains all essential amino acids, has high biological value, and is free of anti-nutritional components and allergens. Myofibrillar proteins, accounting for 50-55% of total meat protein, are structurally important proteins with well-defined physiological functions. However, under low-salt conditions, these proteins assemble into ordered fibrous structures through electrostatic interactions between myosin proteins, making them insoluble. In vitro, the inherent low-salt self-assembly tendency of myosin significantly limits its application in food processing. This limitation hinders the development of novel meat protein-based food products because poor solubility and insufficient colloidal dispersion impede the preparation of low-salt solution systems or homogeneous gel matrices. Although myofibrillar proteins are completely soluble under high-salt conditions, a high-salt diet may increase the risk of cardiovascular, cardiac, and renal diseases. In this context, inhibiting the salt-dependent self-assembly behavior of myofibrillar proteins is a key factor in enhancing the functional applications of meat proteins in food systems. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for preparing an aqueous solution containing myofibrillar protein and its application, which addresses the shortcomings of the prior art. This method enhances the hydrophilicity, electrostatic repulsion and steric hindrance of myofibrillar protein through the synergistic effect of L-glutamic acid and glycosylation, inhibits its self-assembly behavior in a low-salt system, and enhances the solubility and dispersion stability of the aqueous solution containing myofibrillar protein, thus providing technical support for the development of meat products.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing an aqueous solution containing myofibrillar protein, the method being as follows: S1. Extracting myofibrillar protein from pork; S2. Disperse the myofibrillar protein obtained in S1 evenly in water, homogenize it, and obtain a myofibrillar protein suspension. S3. At a temperature of 25°C, L-glutamic acid and the myofibrillar protein suspension obtained in S2 are mixed and stirred to obtain a mixture. S4. Add dextran to the mixture obtained in S3 and stir in a water bath at 37°C to carry out a glycosylation reaction to obtain an aqueous solution containing myofibrillar protein. S5. Store the aqueous solution containing myofibrillar protein obtained in S4 at a temperature of 4°C.

[0005] Preferably, the pork mentioned in S1 is pork tenderloin.

[0006] Preferably, the mass concentration of the myofibrillar protein suspension in S2 is 10 mg / mL.

[0007] Preferably, the homogenization speed in S2 is 6000 r / min, and the homogenization time is 3 min.

[0008] Preferably, the mass of L-glutamic acid in S3 is 7.5% of the mass of myofibrillar protein in the myofibrillar protein suspension.

[0009] Preferably, the stirring rate in S3 is 400 r / min, and the stirring time is 40 min.

[0010] Preferably, the mass ratio of dextran in S4 to myofibrillar protein in the mixture is 1:1; the molecular weight of the dextran is 70 kDa.

[0011] Preferably, the stirring rate in S4 is 400 r / min, and the glycosylation reaction time is 8 h.

[0012] The present invention also provides the application of the aqueous solution containing myofibrillar protein prepared by the above preparation method, wherein the aqueous solution containing myofibrillar protein can inhibit the self-assembly behavior of myofibrillar protein and improve the solubility of myofibrillar protein in a low-salt system.

[0013] Preferably, the low-salt system is a 1 mM NaCl solution.

[0014] Compared with the prior art, the present invention has the following advantages: This invention provides a method for preparing an aqueous solution containing myofibrillar protein that can inhibit the self-assembly behavior of myofibrillar protein under low ionic strength (1 mM salt concentration) and improve its solubility. This method, through the synergistic effect of glutamate and glycosylation, inhibits the self-assembly behavior of protein molecules and enhances the solubility and dispersion stability of myofibrillar protein in a low-salt system (1 mM). The addition of L-glutamate can bind to hydrophobic amino acid residues exposed on the surface of protein molecules through ion-dipole interactions and form hydrogen bonds with water molecules, altering the water network around myosin, increasing the affinity of myofibrillar protein for water, and changing the charge distribution on the protein surface by altering the pH, leading to an increase in positive charge on the protein surface and enhanced electrostatic repulsion between protein molecules. Furthermore, the pretreatment with L-glutamate allows the structure of myofibrillar protein to fully unfold, exposing more glycosylation sites, and enhancing the steric hindrance effect caused by dextran grafting, thus inhibiting the protein's self-assembly behavior. The processed aqueous solution containing myofibrillar protein has higher solubility, lower turbidity, and better storage stability. L-glutamic acid and glucan, as green, healthy, and inexpensive additives, can also be used on a large scale.

[0015] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] Figure 1 This figure illustrates the effect of different preparation methods in Examples 1 and Comparative Examples 1-3 of the present invention on the solubility and turbidity of aqueous solutions containing myofibrillar proteins. Lowercase letters in the figure indicate a significant difference of P < 0.05, and uppercase letters indicate a significant difference of P < 0.05.

[0017] Figure 2 This figure illustrates the effect of different preparation methods in Examples 1 and Comparative Examples 1-3 of this invention on the grafting degree and free amino groups of aqueous solutions containing myofibrillar proteins. Lowercase letters in the figure indicate a significant difference of P < 0.05, and uppercase letters indicate a significant difference of P < 0.05.

[0018] Figure 3 This figure shows the effect of different preparation methods on the particle size of aqueous solutions containing myofibrillar protein in Examples 1 and Comparative Examples 1-3 of this invention. Lowercase letters in the figure indicate significant differences of P < 0.05.

[0019] Figure 4 This describes the effect of different preparation methods in Examples 1 and Comparative Examples 1-3 of the present invention on the microstructure (first row) and appearance (second row) of aqueous solutions containing myofibrillar protein. The appearance of the solution is shown on day 0 and day 14.

[0020] Figure 5This figure shows the effect of different preparation methods on the pH (A) and potential (B) of aqueous solutions containing myofibrillar protein in Examples 1 and Comparative Examples 1-3 of this invention. Lowercase letters in the figure indicate significant differences of P < 0.05.

[0021] Figure 6 This describes the effect of different preparation methods on the fluorescence spectra of aqueous solutions containing myofibrillar proteins in Examples 1 and Comparative Examples 1-3 of the present invention.

[0022] Figure 7 This is a diagram showing the self-assembly behavior of protein molecules in aqueous solutions containing myofibrillar protein subjected to gradient dialysis (0.6 M NaCl, 0.3 M NaCl, 1.0 mM NaCl) using different preparation methods in Examples 1 and Comparative Examples 1-3 of this invention. Detailed Implementation

[0023] The dextran used in this invention is dextran 70, purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with a molecular weight of 70 kDa.

[0024] Example 1 The method for preparing the aqueous solution containing myofibrillar protein in this embodiment is as follows: S1. Extract myofibril protein from pork (pork tenderloin); S2. The myofibrillar protein obtained in S1 is uniformly dispersed in water and homogenized in a homogenizer at a speed of 6000 r / min for 3 min to obtain a myofibrillar protein suspension with a mass concentration of 10 mg / mL. S3. At a temperature of 25°C, L-glutamic acid and the myofibrillar protein suspension obtained in S2 are mixed and stirred at a stirring rate of 400 r / min for 40 min to obtain a mixture; the mass of L-glutamic acid is 7.5% of the myofibrillar protein mass in the myofibrillar protein suspension; S4. Add dextran to the mixture obtained in S3, and stir at a stirring rate of 400 r / min in a water bath at a temperature of 37℃ for 8 hours to carry out the glycosylation reaction, so as to obtain an aqueous solution containing myofibrillar protein; the mass ratio of dextran to myofibrillar protein in the mixture is 1:1. S5. Store the aqueous solution containing myofibrillar protein obtained in S4 at a temperature of 4°C.

[0025] Comparative Example 1 The method for preparing the aqueous solution containing myofibrillar protein in this comparative example is as follows: S1. Extract myofibril protein from pork (pork tenderloin); S2. The myofibrillar protein obtained in S1 is uniformly dispersed in water and homogenized in a homogenizer at a speed of 6000 r / min for 3 min to obtain a myofibrillar protein suspension with a mass concentration of 10 mg / mL. S3. The myofibrillar protein suspension with a mass concentration of 10 mg / mL obtained in S2 was stirred in a water bath at a temperature of 37℃ for 8 hours at a stirring rate of 400 r / min to obtain an aqueous solution containing myofibrillar protein. S4. Store the aqueous solution containing myofibrillar protein obtained in S3 at a temperature of 4°C.

[0026] Comparative Example 2 The method for preparing the aqueous solution containing myofibrillar protein in this comparative example is as follows: S1. Extract myofibril protein from pork (pork tenderloin); S2. The myofibrillar protein obtained in S1 is uniformly dispersed in water and homogenized in a homogenizer at a speed of 6000 r / min for 3 min to obtain a myofibrillar protein suspension with a mass concentration of 10 mg / mL. S3. At a temperature of 25°C, L-glutamic acid and the myofibrillar protein suspension obtained in S2 are mixed and stirred at a stirring rate of 400 r / min for 40 min to obtain a mixture; the mass of L-glutamic acid is 7.5% of the myofibrillar protein mass in the myofibrillar protein suspension; S4. The mixture obtained in S3 is stirred in a water bath at 37°C at a stirring rate of 400 r / min for 8 hours to obtain an aqueous solution containing myofibrillar protein. S5. Store the aqueous solution containing myofibrillar protein obtained in S4 at a temperature of 4°C.

[0027] Comparative Example 3 The method for preparing the aqueous solution containing myofibrillar protein in this comparative example is as follows: S1. Extract myofibril protein from pork (pork tenderloin); S2. The myofibrillar protein obtained in S1 is uniformly dispersed in water and homogenized in a homogenizer at a speed of 6000 r / min for 3 min to obtain a myofibrillar protein suspension with a mass concentration of 10 mg / mL. S3. Add dextran to the myofibrillar protein suspension with a mass concentration of 10 mg / mL obtained in S2, and stir at a stirring rate of 400 r / min in a water bath at a temperature of 37°C for 8 hours to carry out the glycosylation reaction, thereby obtaining an aqueous solution containing myofibrillar protein; the mass ratio of dextran to myofibrillar protein in the suspension is 1:1; the molecular weight of the dextran is 70 kDa; S4. Store the aqueous solution containing myofibrillar protein obtained in S3 at a temperature of 4°C.

[0028] Experiment 1 The aqueous solutions containing myofibrillar protein prepared using different processes in Examples 1 and Comparative Examples 1-3 were diluted with deionized water to a concentration of 1 mg / mL. The solutions were centrifuged at 5000g and 4°C for 10 min using a refrigerated centrifuge, and the supernatant was collected. The protein concentration before and after centrifugation was determined using the BCA method, and the final solubility was calculated using the following formula: Solubility (%) = Protein concentration in the supernatant after centrifugation / Protein stock concentration before centrifugation × 100; The aqueous solutions containing myofibrillar protein prepared using different processes in Examples 1 and Comparative Examples 1-3 were diluted with deionized water to a myofibrillar protein concentration of 1 mg / mL. The absorbance of the sample at 600 nm was measured using a visible light spectrophotometer and used as the turbidity of the sample.

[0029] This experiment was performed in 3 independent replicates (n=3), and the data are expressed as mean ± standard deviation.

[0030] like Figure 1As shown, Comparative Example 1 exhibited low solubility (7.07 ± 0.61%) but high turbidity (0.87 ± 0.01). This is attributed to the different charge clusters in the rod region of myosin, and the strong electrostatic attraction between these different charge clusters drives intermolecular self-assembly, causing myofibrillar proteins to spontaneously form filamentous polymers in low ionic strength media, thus rendering them insoluble and resulting in increased turbidity. In Comparative Examples 2 and 3, the solubility of myofibrillar proteins significantly increased, reaching 24 ± 1.47% and 44.4 ± 0.43%, respectively, while the turbidity decreased to 0.72 ± 0.00 and 0.1 ± 0.01, respectively. This improvement is because dextran conjugation can enhance protein solubility by altering electrostatic charge and strengthening steric hindrance in the myosin molecular structure. L-glutamic acid, as an acidic amino acid, lowers the pH of the system, altering the charge distribution on the protein surface, enhancing electrostatic repulsion between protein molecules, and ultimately inhibiting myosin self-assembly, thereby improving the water solubility of myofibrillar proteins. The solubility of Example 1 was significantly better than that of Comparative Examples 2 and 3, with an increase of 50.83 ± 0.65%. This indicates that the combined treatment of L-glutamic acid and dextran had a positive synergistic effect.

[0031] Experiment 2 The aqueous solutions containing myofibrillar protein prepared by different processes in Examples 1 and Comparative Examples 1-3 were mixed with OPA reagent at a ratio of 1:20, vortexed, and reacted at 35°C for 3 min. The absorbance of the mixture was measured at 340 nm. The number of free amino groups and the degree of grafting were calculated as follows: Free amino groups (%) = Absorbance value of the sample after reaction / Absorbance value of the sample before reaction × 100; Grafting degree (%) = (Absorbance value of sample before reaction - Absorbance value of sample after reaction) / Absorbance value of sample before reaction × 100; This experiment was performed in 3 independent replicates (n=3), and the data are expressed as mean ± standard deviation.

[0032] like Figure 2 As shown, the grafting degree of Example 1 reached 27.93 ± 0.75%, while that of Comparative Example 2 was only 17.18 ± 0.91%. The change in grafting degree may reflect changes in the number and availability of glycosylation sites. After treatment with L-glutamate, the myofibrillar protein structure unfolded, the α-helix content decreased, and the protein folded. This protein unfolding may have provided more binding sites for dextran.

[0033] Experiment 3 The aqueous solutions containing myofibrillar protein prepared by different processes in Example 1 and Comparative Examples 1-3 were directly measured using a laser particle size analyzer. This experiment was performed in 3 independent replicates (n=3), and the data are expressed as mean ± standard deviation.

[0034] Solution micron-sized particles, such as Figure 3 As shown, the particle sizes of Comparative Examples 1-3 and Example 1 are 79.34±1.22 μm, 42.89±1.42 μm, 46.37±0.50 μm, and 55.4±0.45 μm, respectively. Comparative Example 1 exhibits the largest particle size, which is attributed to the attraction and self-assembly of periodically distributed charged clusters at the tail of myosin in low ionic strength solutions, forming ordered fibrous structures. Compared to Comparative Example 1, the large particle size of Comparative Example 2 is reduced, which is related to the enhanced steric hindrance effect caused by glycosylation treatment, inhibiting the assembly of myosin filaments. In addition, we found that the particle size of Example 1 tends to increase compared to Example 3. This may be due to the large-scale transformation of the rigid α-helical structure into a flexible β-sheet structure after L-glutamic acid treatment, promoting the formation of early oligomers or pre-fiber aggregates. When dextran is added, the covalent cross-linking effect of glycosylation can further "lock" the oligomeric state, promoting the formation of soluble macromolecular aggregates, resulting in increased particle size.

[0035] Experiment 4 Take 4 mL of each of the myofibrillar protein-containing aqueous solutions prepared by different processes in Example 1 and Comparative Examples 1-3, mix them with a staining solution containing 1.0 g / L Nile blue, shake well, and let stand for 30 min. Place 5 μL of the stained sample onto a glass slide, cover with the slide, and seal. Observe the microstructure and distribution of the myofibrillar protein-containing aqueous solution using a confocal laser scanning microscope, and take typical fluorescence images under a 40x objective lens. Figure 4 As shown in the first row of figures, Comparative Example 1 exhibits a large, highly ordered fibrous structure, while Comparative Examples 2 and 3 reveal that the original fibrous structure has depolymerized into shorter fibrous structures. Compared to Comparative Example 1, the laser confocal microscopy image of Example 1 shows smaller myosin aggregates, further demonstrating that the self-assembly behavior of myofibrillar proteins is inhibited. Furthermore, due to its unique myofibrillar protein self-assembly inhibition mechanism, Example 1's image shows larger aggregates compared to Comparative Example 3.

[0036] Experiment 5 The aqueous solutions containing myofibrillar protein prepared by different processes in Example 1 and Comparative Examples 1-3 were placed into sample appearance bottles, and the appearance of the samples was observed after standing for 3 minutes (day 0). The samples were then stored in a 4°C freezer away from light for 14 days, and the appearance of the samples was observed again. Figure 4 ( Figure 4As shown in the second row of figures, corresponding to the turbidity results, after storage at 4°C for 14 days, Comparative Examples 1, 2, 3, and 1 showed varying degrees of phase separation. In Comparative Example 1, myofibrillar proteins almost completely migrated to the bottom of the bottle, indicating that the aqueous solution containing myofibrillar proteins has very poor dispersion stability. The migration levels in Comparative Examples 2, 3, and 1 were all reduced to varying degrees; in Example 1, almost no visible migration was observed, demonstrating that the treatment method of the present invention significantly enhances the storage stability of the protein.

[0037] Experiment Six The aqueous solutions containing myofibrillar protein prepared by different processes in Example 1 and Comparative Examples 1-3 were removed from the freezer at 4°C and allowed to stand until the solutions returned to room temperature. Then, the pH was measured using an automatic pH meter. This experiment was performed in three independent replicates (n=3), and the data are expressed as mean ± standard deviation.

[0038] like Figure 5 As shown in Figure A, the pH values ​​of Comparative Examples 1-3 and Example 1 were 6.29±0.02, 6.30±0.02, 4.53±0.02, and 4.52±0.03, respectively. This indicates that glycosylation treatment had almost no effect on the pH value of the myofibrillar protein solution. The pH change was mainly affected by L-glutamate, further demonstrating that the protein charge change and enhanced electrostatic repulsion caused by pH reduction were mainly caused by L-glutamate. Furthermore, although the pH of the examples changed, it remained within the prescribed range for edible product manufacturing and processing, and would not have a significant impact on sensory or human health.

[0039] Experiment 7 The aqueous solutions containing myofibrillar protein prepared by different processes in Example 1 and Comparative Examples 1-3 were diluted to 0.1 mg / ml, and the zeta potential was measured using a particle size potentiometer. This experiment was performed in 3 independent replicates (n=3), and the data are expressed as mean ± standard deviation.

[0040] like Figure 5 As shown in Figure B, the potential value of Comparative Example 2 is -11.81 ± 0.36 mV, which is significantly higher in absolute value than the potential value of Comparative Example 1 (-11.81 ± 0.3 mV). This is because glycosylation causes the condensation reaction between the amino acid and the reduced carbonyl group to consume the positively charged ε-amino group and introduce the negatively charged hydroxyl group. However, compared to Comparative Examples 1 and 2, the zeta potential of Comparative Example 3 is positive, at 16.07 ± 0.15 mV. This is because L-glutamic acid contains two carboxyl groups, which dissociate in aqueous solution, releasing a large number of hydrogen ions (H+). +This causes a decrease in pH. When the pH decreases, the dissociation of acidic groups such as carboxyl groups on the protein surface is inhibited, while the protonation of basic groups such as amino groups increases, thereby altering the charge distribution on the protein surface, leading to an increase in positive charge and a higher zeta potential. Further observation revealed that the potential value in Example 1 increased to 20.93 ± 2.51 mV. We speculate that negatively charged groups may preferentially bind to the positive charge in certain specific regions of the protein surface, resulting in a relatively more concentrated positive charge in other regions of the protein surface, thus increasing the overall positive potential. When the zeta potential of a protein is high (positive or negative), the electrostatic repulsion between protein molecules with the same charge increases, which inhibits the self-assembly of myosin molecules. Therefore, Example 1 has a strong inhibitory effect on the self-assembly of myofibrillar proteins, improving the solubility and stability of myofibrillar proteins in water.

[0041] Experiment 8 The aqueous solutions containing myofibrillar protein prepared using different processes in Examples 1 and Comparative Examples 1-3 were diluted to 0.1 mg / mL, and emission spectra were measured using a fluorescence spectrophotometer in the wavelength range of 300 nm to 400 nm at a scan rate of 600 nm / min. The excitation wavelength was set to 283 nm, the excitation and emission slit widths were 5.0 nm, and the data interval was 0.5 nm. Figure 6 As shown, Comparative Example 1 exhibits the highest fluorescence intensity because the untreated myofibrillar protein structure is stable, with tryptophan residues embedded in the protein's hydrophobic core. Compared to Comparative Example 1, the fluorescence intensity of the proteins in Comparative Examples 2 and 3 is reduced to varying degrees. Dextran, with its large molecular weight and spatial structure, provides a strong steric hindrance effect upon reaction with myofibrillar protein, inhibiting protein self-assembly, causing the protein structure to unfold, and making the microenvironment of tryptophan residues more polar, resulting in decreased fluorescence intensity and a redshift of the maximum emission wavelength (λmax). The addition of L-glutamate increases electrostatic repulsion between protein molecules, which may lead to relaxation or local unfolding of the protein surface structure, exposing tryptophan residues to a polar environment, thus also reducing fluorescence intensity and causing a redshift of the maximum emission wavelength (λmax). Simultaneously, charged L-glutamate may reduce fluorescence intensity by perturbing the excited state energy level of tryptophan or by forming a non-covalent complex through hydrogen bonding, leading to static fluorescence quenching. The fluorescence intensity of Example 1 further decreased, indicating that the synergistic effect of L-glutamate and glycosylation treatment caused the myofibrillar protein structure to further unfold and inhibit the assembly of myosin filaments.

[0042] Experiment Nine The aqueous solutions containing myofibrillar protein prepared by different processes in Examples 1 and Comparative Examples 1-3 were subjected to gradient dialysis to simulate the self-assembly process of protein molecules. First, the samples were dialyzed in a high ionic strength solution (0.6 M NaCl, pH 7.0) for 24 hours, followed by centrifugation at 7,000 g for 10 minutes at 4 °C for protein purification. Then, the supernatant was dialyzed sequentially in medium ionic strength (0.3 M NaCl, pH 7.0) and low ionic strength (1.0 mM NaCl, pH 7.0) solutions for 24 hours. The protein solution was retained at each dialysis stage, and transmission electron microscopy was used to observe the microscopic morphology of the protein samples at each stage of the self-assembly process. When using transmission electron microscopy, the aqueous solutions containing myofibrillar protein prepared by different processes in Examples 1 and Comparative Examples 1-3 were first diluted to a myofibrillar protein concentration of 0.1 mg / mL, and 5.0 μL of each solution was added dropwise to a carbon-coated copper mesh and fixed for 1 hour. Subsequently, it was stained with 4% uranyl acetate for 2 minutes, air-dried, and observed at 2000x magnification under an accelerating voltage of 100 kV. Figure 7 As shown, in Comparative Example 1, the morphology of myofibrillar protein changed from a dispersed state to an aggregated state as the salt concentration decreased, indicating that the self-assembly of myosin molecules continued to occur under low-salt conditions, resulting in poor solubility and increased turbidity of myofibrillar protein. In contrast, in Example 1, as the salt concentration decreased, the transmission electron microscopy image showed the disappearance of organized coarse filaments and the formation of disordered filamentous oligomers, which was consistent with the observation results of particle size and laser confocal microscopy images. This further proved that the synergistic effect of L-glutamate and glycosylation treatment effectively inhibited the self-assembly process of myosin molecules, making myofibrillar protein more soluble in low ionic strength solutions (1.0 mM NaCl, pH 7.0).

[0043] The aqueous solution containing myofibrillar protein prepared in Example 1 effectively inhibits the self-assembly behavior of myofibrillar protein and improves its solubility under low-salt conditions. In practical applications, this method utilizes dextran and L-glutamic acid, both of which are green and non-toxic food additives. It allows for the production of aqueous solutions containing myofibrillar protein with excellent solubility and dispersion stability without the need for large-scale equipment. The use of dextran and L-glutamic acid as green and non-toxic food additives provides technical support for low-salt protein beverages and protein nutrient solutions.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing an aqueous solution containing myofibrillar protein, characterized in that, The method is as follows: S1. Extracting myofibrillar protein from pork; S2. Disperse the myofibrillar protein obtained in S1 evenly in water, homogenize it, and obtain a myofibrillar protein suspension. S3. At a temperature of 25°C, L-glutamic acid and the myofibrillar protein suspension obtained in S2 are mixed and stirred to obtain a mixture. S4. Add dextran to the mixture obtained in S3 and stir in a water bath at 37°C to carry out a glycosylation reaction to obtain an aqueous solution containing myofibrillar protein. S5. Store the aqueous solution containing myofibrillar protein obtained in S4 at a temperature of 4°C.

2. The method for preparing an aqueous solution containing myofibrillar protein according to claim 1, characterized in that, The pork mentioned in S1 refers to pork tenderloin.

3. The method for preparing an aqueous solution containing myofibrillar protein according to claim 1, characterized in that, The mass concentration of myofibrillar protein suspension in S2 is 10 mg / mL.

4. The method for preparing an aqueous solution containing myofibrillar protein according to claim 1, characterized in that, In S2, the homogenization speed is 6000 r / min, and the homogenization time is 3 min.

5. The method for preparing an aqueous solution containing myofibrillar protein according to claim 1, characterized in that, The mass of L-glutamic acid in S3 is 7.5% of the mass of myofibrillar protein in the myofibrillar protein suspension.

6. The method for preparing an aqueous solution containing myofibrillar protein according to claim 1, characterized in that, The stirring speed in S3 is 400 r / min, and the stirring time is 40 min.

7. The method for preparing an aqueous solution containing myofibrillar protein according to claim 1, characterized in that, The mass ratio of dextran in S4 to myofibrillar protein in the mixture is 1:1; the molecular weight of the dextran is 70 kDa.

8. The method for preparing an aqueous solution containing myofibrillar protein according to claim 1, characterized in that, The stirring rate in S4 is 400 / min, and the glycosylation reaction takes 8 h.

9. The application of an aqueous solution containing myofibrillar protein prepared by the preparation method according to any one of claims 1-8, characterized in that, The aqueous solution containing myofibrillar protein can inhibit the self-assembly behavior of myofibrillar protein and increase its solubility in a low-salt system.

10. The application according to claim 9, characterized in that, The low-salt system is a 1 mM NaCl solution.

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