Edible alcohol-induced plant protein-polysaccharide double network gel, and preparation method and application thereof

Abstract

The application discloses edible alcohol-induced plant protein-polymer double network gel and a preparation method and application thereof, and belongs to the technical field of food. The double network gel is prepared by the following method: mixing a plant protein hydrogel and a polymer supramolecular nanofiber, high-speed shearing, and obtaining a protein microgel system; then adding gluconic acid-delta-lactone and a calcium source, and standing at 1-10 DEG C to form a plant protein microgel-polymer supramolecular nanofiber double network gel. The application uses ethanol as a green inducer, simultaneously realizes plant protein conformation unfolding and polymer molecule self-assembly in the same system, constructs a double network structure of a protein continuous network and a polymer supramolecular nanofiber reinforced skeleton, breaks through the traditional polymer function mode of only serving as a filling phase, and significantly enhances the synergistic effect between the networks.

Description

Technical Field

[0001] This invention belongs to the field of food technology, specifically relating to an edible alcohol-induced plant protein-polysaccharide dual-network gel, its preparation method, and its application. Background Technology

[0002] Plant proteins (such as peanut and soy protein isolate) have advantages such as wide availability, high nutritional value, low allergenicity, and environmental friendliness. Hydrogels constructed from them show great promise in areas such as simulating meat textures, fat substitution, and delivery of active substances. However, natural plant proteins often exhibit a dense spherical conformation with embedded hydrophobic groups, making it difficult for unmodified protein molecules to fully expand and recombine. The resulting single-network gels generally suffer from low mechanical strength, fragile structure, poor cohesion, and insufficient water-holding capacity, failing to meet the requirements of high-quality plant-based foods. To address these issues, existing technologies often introduce polysaccharides such as sodium alginate to construct dual-network systems, improving mechanical properties through synergistic effects between networks. However, existing polysaccharide-protein composite systems still have significant limitations. Sodium alginate mainly exhibits a random coil conformation in aqueous solution, lacking structural guidance. To address the technical problems of fragile plant protein gel network structures, low mechanical strength, and poor stress transfer efficiency in polysaccharide-protein composite systems, this paper proposes a method for constructing a dual-network structure based on the synergistic combination of sugar supramolecular nanofibers and plant protein hydrogels, which is of great significance for improving the performance of plant protein gels. Summary of the Invention

[0003] This invention constructs a dual-network gel system with polysaccharide supramolecular nanofibers as the reinforcing framework and a plant protein gel network forming a spatially interpenetrating structure, achieving a synergistic improvement in gel structure and mechanical properties. This hydrogel can serve as a high-quality plant-based meat substitute, a low-fat food base, and a stable delivery carrier for functional factors.

[0004] The technical solution of the present invention is as follows: This invention provides a plant protein-polysaccharide dual-network gel, prepared by the following method: Plant protein hydrogels were mixed with polysaccharide supramolecular nanofibers and subjected to high-speed shearing to obtain a protein microgel system. Then, gluconate-δ-lactone and a calcium source were added, and the mixture was allowed to stand at 1~10℃ to form a plant protein-polysaccharide double network gel.

[0005] In the above technical solution, the volume ratio of the plant protein hydrogel to the polysaccharide supramolecular nanofiber is (1~3):(1~3); preferably 1:1.

[0006] In the above technical solution, the conditions for high-speed shearing are: high-speed shearing at 8000~12000 rpm for 1~5 min.

[0007] In the above technical solution, the final concentration of gluconate-δ-lactone in the system is 0.5~2% (w / v); preferably 0.8% (w / v).

[0008] In the above technical solution, the calcium source is at least one of calcium carbonate, calcium sulfate, calcium phosphate, and calcium hydrogen phosphate; preferably calcium carbonate; the final concentration of the calcium source in the system is 0.1~1% (w / v); preferably 0.4% (w / v).

[0009] In the above technical solution, the plant protein hydrogel is prepared by the following method: Plant protein is dispersed in water, and the pH value is adjusted to form a plant protein suspension. Then, the plant protein suspension is mixed with ethanol, heated, and cooled to form a plant protein hydrogel.

[0010] In the above method for preparing plant protein hydrogels, the pH is adjusted using NaOH solution, with a concentration of 1-5 mol / L, preferably 2 mol / L; the pH value is 3-9, preferably 7.

[0011] In the above method for preparing plant protein hydrogels, the concentration of the plant protein suspension is 3-20% (w / v); preferably 7.5% (w / v).

[0012] In the above method for preparing plant protein hydrogels, the plant protein is at least one of peanut protein, soybean protein, pea protein, quinoa protein, potato protein, mung bean protein, and chickpea protein.

[0013] In the above method for preparing plant protein hydrogel, the volume ratio of the plant protein suspension to ethanol is (1~10):1; preferably 4:1.

[0014] In the above method for preparing plant protein hydrogels, the heat treatment conditions are: heating at 80~95℃ for 5~15 min; preferably: heating at 85℃ for 10 min.

[0015] In the above technical solution, the polysaccharide supramolecular nanofibers are prepared by the following method: ethanol is added dropwise to the polysaccharide solution and stirred to form polysaccharide supramolecular nanofibers.

[0016] In the preparation method of polysaccharide supramolecular nanofibers, the volume ratio of ethanol to polysaccharide solution is 1:(1~10); preferably 1:4.

[0017] In the preparation method of polysaccharide supramolecular nanofibers, the concentration of polysaccharide in the polysaccharide supramolecular nanofibers is 1~5% (w / v); preferably 2% (w / v).

[0018] In the preparation method of polysaccharide supramolecular nanofibers, the polysaccharide is at least one of sodium alginate and pectin.

[0019] This invention provides the application of the above-mentioned plant protein-polysaccharide dual-network gel in meat texture simulation (production of plant-based biomimetic meat products), fat substitution, or delivery of active substances.

[0020] This invention provides a plant-based biomimetic meat product, prepared by the following method: The above-mentioned plant protein-polysaccharide dual-network gel was mixed with the plant protein base material, stirred evenly, degassed, pressed into shape, and then heated in a water bath. After the heating was completed, it was cooled to room temperature and allowed to stand to obtain plant-based biomimetic meat products.

[0021] In the above-mentioned method for preparing plant-based biomimetic meat products, the mass ratio of the plant protein-polysaccharide dual-network gel to the plant protein base is 1:(2~6); the plant protein base is composed of a mixture of plant protein and water, and its mass concentration is 5~10%; the water bath heating conditions are: heating at 80~100℃ for 5~20min; the standing conditions are: standing at 1~5℃ for 1~3h.

[0022] The beneficial effects of this invention are as follows: This invention utilizes ethanol as a green inducer to simultaneously achieve the conformational unfolding of plant proteins and the self-assembly of polysaccharide molecules in the same system, constructing a dual-network structure of a continuous protein network and a polysaccharide supramolecular nanofiber-reinforced framework. This breaks through the traditional mode of polysaccharides acting only as a filler phase and significantly enhances the synergistic effect between networks.

[0023] The dual-network gel prepared by this invention can serve as a high-quality fat substitute, significantly improving the quality and efficacy of plant-based foods while reducing health risks such as cholesterol intake. Furthermore, its dense and uniform three-dimensional network structure provides an ideal stable delivery system for photothermal-sensitive active ingredients, and has broad commercial application prospects in the development of functional gummies and other health foods. Attached Figure Description

[0024] Figure 1 The images show actual photos of the plant protein-polysaccharide gels; where A is Example 1, B is Comparative Example 1, C is Comparative Example 2, and D is Comparative Example 3.

[0025] Figure 2 SEM images of the plant protein-polysaccharide gels are shown below; where A is Example 1, B is Comparative Example 1, C is Comparative Example 2, and D is Comparative Example 3.

[0026] Figure 3 Rheological properties of various plant protein-polysaccharide gels were tested.

[0027] Figure 4 The results are from an in vitro simulated digestion and release experiment.

[0028] Figure 5 This is the result of sensory evaluation. Detailed Implementation

[0029] In this invention, the peanut protein powder comes from Qingdao Changshou Food Co., Ltd., and the peanut protein is obtained by alkali dissolution and acid precipitation extraction of peanut protein powder.

[0030] Other materials used in this invention, unless otherwise stated, are commercially available. Other terms used in this invention, unless otherwise stated, generally have the meanings commonly understood by those skilled in the art. The invention is further described in detail below with reference to specific embodiments and data. The following embodiments are merely illustrative and not intended to limit the scope of the invention in any way.

[0031] Example 1

[0032] The steps for preparing a peanut protein-sodium alginate dual-network gel are as follows: (1) Peanut protein suspension Peanut protein was dispersed in distilled water, and the pH was adjusted to 7 using NaOH solution (2 mol / L) to form a peanut protein suspension with a concentration of 7.5% (w / v).

[0033] (2) Peanut protein hydrogel 16 mL of peanut protein suspension was mixed with 4 mL of ethanol to obtain a peanut protein-ethanol mixture. The mixture was then heated at 85 °C for 10 min and cooled to form a peanut protein hydrogel.

[0034] (3) Sodium alginate supramolecular nanofibers Sodium alginate was dispersed in distilled water to form a sodium alginate solution. 4 mL of ethanol was added dropwise to 16 mL of the sodium alginate solution and stirred for 6 h to form sodium alginate supramolecular nanofibers with a concentration of 2% (w / v).

[0035] (4) Peanut protein-sodium alginate dual-network gel Peanut protein hydrogel and sodium alginate supramolecular nanofibers were mixed at a volume ratio of 1:1 and sheared at 10,000 rpm for 2 min to obtain a protein microgel system. Then, gluconate-δ-lactone (GDL, final concentration 0.8% (w / v)) and calcium carbonate (final concentration 0.4% (w / v)) were added, and the mixture was allowed to stand at 4℃ for 2 h to induce acidification and ionic cross-linking, forming a peanut protein-sodium alginate double network gel.

[0036] Comparative Example 1 In this comparative example, a peanut protein-sodium alginate dual-network gel was prepared. The preparation method was basically the same as that in Example 1. The difference was that in step (4), sodium alginate supramolecular nanofibers were replaced with sodium alginate solution with a concentration of 2% (w / v).

[0037] Comparative Example 2 In this comparative example, a peanut protein-sodium alginate dual-network gel was prepared. The preparation method was basically the same as that in Example 1. The difference was that in step (4), the peanut protein hydrogel was replaced with a peanut protein suspension with a concentration of 7.5% (w / v).

[0038] Comparative Example 3 In this comparative example, a peanut protein-sodium alginate dual-network gel was prepared. The preparation method was basically the same as that in Example 1. The difference was that in step (4), the peanut protein hydrogel was replaced with peanut protein suspension with a concentration of 7.5% (w / v); and the sodium alginate supramolecular nanofibers were replaced with sodium alginate solution with a concentration of 2% (w / v).

[0039] I. Structural Characterization The morphology of the double-network gel was observed by taking photographs, such as... Figure 1 As shown. The microstructure of the dual-network gel was observed using SEM images, as shown. Figure 2 As shown.

[0040] Depend on Figure 1 and Figure 2 As can be seen, the dual-network gel of Example 1 has a superior morphology and a dense microstructure, with smaller pores and thicker pore walls at the same magnification. This dense and uniform network structure facilitates the formation of effective stress transfer paths, enabling the uniform dispersion of stress under external forces, thereby improving the mechanical strength and resistance to damage of the gel. Simultaneously, the thicker pore walls enhance the supporting effect of the network, contributing to improved elasticity and cohesion of the gel. Furthermore, the smaller and more uniform pore structure effectively restricts water migration, increasing the water binding capacity within the network, thus enhancing the gel's water retention and structural stability.

[0041] In contrast, the microstructure of the dual-network gels obtained in Comparative Examples 1-3 exhibits larger and unevenly distributed pores, thinner pore walls, and a relatively loose network structure. These structural defects lead to discontinuous stress transmission paths within the gel, making it prone to localized stress concentration under stress, thus reducing the gel's mechanical strength and stability. Simultaneously, the thinner pore walls fail to provide effective support, making the gel more susceptible to structural collapse or breakage. Furthermore, the larger pore structure hinders effective water retention, easily causing water migration and loss, thereby reducing its water-holding capacity and overall stability.

[0042] II. Mechanical Property Testing The dual-network gel was prepared into cylinders with a height of 10 mm and a diameter of 20 mm and stored overnight in a refrigerator at 4°C. Then, the hardness, elasticity, viscosity, and chewiness of the gel were measured using a texture analyzer equipped with a P / 0.5 probe (TA-XT plus, Stable Micro Systems Ltd., England). Parameters: speed was set to 1 mm / s before and after testing, and the testing speed was set to 1 mm / s. The sample was compressed by 50% under a trigger force of 5 g.

[0043] The test results are shown in Table 1: Table 1. Texture parameters of the dual-network gel

[0044] As shown in Table 1, the hardness, elasticity, viscosity and chewiness of the dual-network gel prepared in Example 1 are significantly enhanced.

[0045] III. Rheological Performance Testing The storage modulus and loss modulus of the dual-network gel were measured using an interfacial rheometer (MCR302, Anton Paar GmbH, Austria) equipped with a PP25 probe. Parameters: temperature set to 25°C, strain set to 1%, and angular frequency range set to 0.1-100 rad / s.

[0046] Test results are as follows Figure 3 As shown: The dual-network gel prepared in Example 1 has the highest energy storage modulus, and the resulting gel network is more compact.

[0047] Application Example 1 The steps for preparing the curcumin delivery vector are as follows: Curcumin was dissolved in anhydrous ethanol to prepare a curcumin ethanol solution with a mass concentration of 10 mg / mL. Under light-protected conditions, the curcumin ethanol solution was slowly added dropwise to the peanut protein suspension prepared in step (1) of Example 1, and stirred continuously for 30 min to ensure that curcumin was fully dispersed in the system. The final amount of curcumin added was controlled to be 0.1% of the total mass of the system.

[0048] Subsequently, a peanut protein-sodium alginate dual-network gel loaded with curcumin was prepared according to the method in Example 1, and the specific steps are as follows: Peanut protein hydrogel loaded with curcumin was mixed with sodium alginate supramolecular nanofibers at a volume ratio of 1:1 and sheared at 10,000 rpm for 2 min to obtain a homogeneous protein microgel system. Then, gluconate-δ-lactone (GDL) was added to a final concentration of 0.8% (w / v), and calcium carbonate was added to a final concentration of 0.4% (w / v). The mixture was then allowed to stand at 4℃ for 2 h to form a curcumin-loaded peanut protein-sodium alginate double network gel.

[0049] The resulting dual-network gel has a dense and uniform three-dimensional network structure, which can be used as a stable delivery carrier for curcumin.

[0050] IV. Encapsulation Performance Testing Curcumin was extracted from the gel using ethanol extraction, and the curcumin content was determined by ultraviolet spectrophotometry. The encapsulation efficiency and drug loading were then calculated.

[0051] The test results are shown in Table 2: Table 2 Encapsulation performance parameters of dual-network gels

[0052] The results show that the dual-network gel of the present invention has good encapsulation ability for curcumin, with an encapsulation rate of over 85%, indicating that the dual-network structure can effectively restrict curcumin migration and improve its loading stability.

[0053] V. In vitro simulated digestion and release experiment Curcumin release behavior was evaluated using simulated gastric juice (SGF, pH=2.0) and simulated intestinal juice (SIF, pH=7.0).

[0054] The curcumin-loaded double-network gel was digested in simulated gastric juice at 37°C for 2 h, and then transferred to simulated intestinal juice for further digestion for 6 h. The curcumin concentration in the release medium was measured at regular intervals.

[0055] Test results are as follows Figure 4 As shown.

[0056] The dual-network gel of this invention maintains good structural integrity in the gastric fluid environment, with a cumulative release rate of less than 20% in 2 hours; after entering the intestinal fluid environment, the gel gradually expands and degrades, with a cumulative release rate of more than 80% in 6 hours, achieving significant gastric protection and intestinal sustained-release effects.

[0057] In summary, the plant protein-polysaccharide dual-network gel constructed in this invention can significantly improve the encapsulation efficiency and environmental stability of curcumin, achieving a controlled-release effect with low release in gastric juice environment and continuous release in intestinal juice environment. It can serve as an important carrier for functional foods, fortified foods, and active substance delivery systems.

[0058] Application Example 2 The steps for preparing plant-based biomimetic meat products are as follows: The peanut protein-sodium alginate dual-network gel prepared in Example 1 was used as a structural reinforcing component and a fat-mimicking component for the preparation of plant-based biomimetic meat products.

[0059] 80 g of soy protein isolate was added to 920 g of deionized water and stirred at room temperature for 30 min to obtain a soy protein base with a mass concentration of 8% (w / v). The double-network gel was mixed with the soy protein base at a mass ratio of 20:80 and stirred at 500 rpm for 10 min to ensure homogeneity. The mixture was then degassed at -0.08 MPa for 10 min using a vacuum degassing machine, and the resulting mixture was placed into a mold for pressing and shaping. The mold was heated in a 90℃ water bath for 10 min to further aggregate the plant proteins and form a continuous network structure. After heating, the mixture was rapidly cooled to room temperature and allowed to stand at 4℃ for 2 h to obtain a plant-based biomimetic meat sample.

[0060] VI. Analysis of Texture Properties The prepared plant-based biomimetic meat samples were cut into cylinders with a height of 10 mm and a diameter of 20 mm and stored at 4°C for 12 h for equilibration. The hardness, elasticity, and chewiness of the samples were determined using a texture analyzer (TA-XT Plus, Stable Micro Systems Ltd., UK). A P / 0.5 cylindrical probe was used for testing, with a pre-test speed of 1 mm / s, a test speed of 1 mm / s, and a post-test speed of 1 mm / s. The trigger force was 5 g, the compression ratio was 50%, and the interval between two compressions was 5 s. Each sample was measured in parallel at least three times, and the average value was taken as the final result. Soy protein-based biomimetic meat products prepared without the addition of a double-network gel were used as a control.

[0061] The test results are shown in Table 3: Table 3 Texture parameters of biomimetic meat products based on dual-network gel

[0062] The results showed that, compared with the control group without the addition of dual-network gel, the biomimetic meat sample of the present invention had significantly improved hardness, elasticity and chewiness, exhibiting a tissue structure that was closer to that of real meat products.

[0063] VII. Determination of Cooking Loss The mass change of the plant-based biomimetic meat sample was measured after heating it in a 90℃ water bath for 20 min.

[0064] The test results are shown in Table 4: Table 4 Cooking loss of biomimetic meat products based on dual-network gel

[0065] The results show that the cooking loss rate of the sample of the present invention can be controlled below 10%, which is significantly lower than that of the control group without the addition of dual-network gel, indicating that the dual-network structure can effectively reduce moisture loss during processing.

[0066] VIII. Sensory Evaluation The samples were evaluated by 10-15 trained evaluators on their texture, elasticity, juiciness, chewiness, and overall acceptability. The test results are as follows: Figure 5 As shown.

[0067] The results showed that after adding the dual-network gel, the sample was significantly better than the control group in terms of elasticity, juiciness and overall acceptability, and had a sensory quality that was closer to that of animal meat products.

[0068] In summary, the plant protein-polysaccharide dual-network gel of this invention combines the supporting role of a continuous protein network with the reinforcing role of a polysaccharide nanofiber-reinforced skeleton, significantly improving the tissue structure, water retention, and processing stability of plant-based biomimetic meat. Furthermore, this dual-network structure can also partially replace oils as a fat mimic, reducing fat content while maintaining good texture and mouthfeel, thus showing broad application prospects in plant-based meat products.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A plant protein-polysaccharide dual-network gel, characterized in that, It is prepared by the following method: Plant protein hydrogels were mixed with polysaccharide supramolecular nanofibers and subjected to high-speed shearing to obtain a protein microgel system. Then, gluconate-δ-lactone and a calcium source were added, and the mixture was allowed to stand at 1~10℃ to form a plant protein-polysaccharide double network gel.

2. The plant protein-polysaccharide dual-network gel according to claim 1, characterized in that, The volume ratio of the plant protein hydrogel to the polysaccharide supramolecular nanofibers is (1~3):(1~3); the final concentration of the gluconate-δ-lactone in the system is 0.5~2% (w / v); the calcium source is at least one of calcium carbonate, calcium sulfate, calcium phosphate and calcium hydrogen phosphate; the final concentration of the calcium source in the system is 0.1~1% (w / v).

3. The plant protein-polysaccharide dual-network gel according to claim 1, characterized in that, The conditions for high-speed shearing are: high-speed shearing at 8000~12000 rpm for 1~5 min.

4. The plant protein-polysaccharide dual-network gel according to claim 1, characterized in that, The plant protein hydrogel was prepared by the following method: Plant protein is dispersed in water, and the pH value is adjusted to form a plant protein suspension. Then, the plant protein suspension is mixed with ethanol, heated, and after cooling, a plant protein hydrogel is formed.

5. The plant protein-polysaccharide dual-network gel according to claim 4, characterized in that, The concentration of the plant protein suspension is 3-20% (w / v); the plant protein is at least one of peanut protein, soybean protein, pea protein, quinoa protein, potato protein, mung bean protein, and chickpea protein; the volume ratio of the plant protein suspension to ethanol is (1-10):1; the heating conditions are: heating at 80-95℃ for 5-15 minutes.

6. The plant protein-polysaccharide dual-network gel according to claim 1, characterized in that, The polysaccharide supramolecular nanofibers are prepared by the following method: ethanol is added dropwise to a polysaccharide solution and stirred to form polysaccharide supramolecular nanofibers.

7. The plant protein-polysaccharide dual-network gel according to claim 6, characterized in that, The volume ratio of ethanol to polysaccharide solution is 1:(1~10); the concentration of polysaccharide in the polysaccharide supramolecular nanofibers is 1~5% (w / v); the polysaccharide is at least one of sodium alginate and pectin.

8. The application of the plant protein-polysaccharide dual-network gel of claim 1 in the production of plant-based biomimetic meat products, fat substitution, or delivery of active substances.

9. A plant-based biomimetic meat product, characterized in that, It is prepared by the following method: The plant protein-polysaccharide dual-network gel of claim 1 is mixed with plant protein base material, stirred evenly, defoamed, pressed into shape, and then heated in a water bath. After the heating is completed, it is cooled to room temperature and allowed to stand to obtain plant-based biomimetic meat products.

10. The plant-based biomimetic meat product according to claim 9, characterized in that, The mass ratio of the plant protein-polysaccharide dual-network gel to the plant protein base is 1:(2~6); the plant protein base is a mixture of plant protein and water with a mass concentration of 5~10%; the water bath heating conditions are: heating at 80~100℃ for 5~20min; the standing conditions are: standing at 1~5℃ for 1~3h.

Images