Method for modifying protein nano fibril with high foamability

Abstract

The invention relates to the technical field of biological materials, in particular to a high-foamability protein nanofibril modification method which comprises the steps of chickpea protein isolate solution preparation and protein fibrosis treatment. According to the method, by strictly controlling the conditions of each step, such as solution concentration, pH value, hydration and heating time and the like, the size of the protein nano fibril is precisely regulated and controlled, uniform fiber with the length of 50-200 nm is obtained, the protein nano fibril is endowed with excellent foaming performance, the foaming capacity and stability are remarkably improved, and the emulsifying performance is not sacrificed. Meanwhile, the fiber has a definite adding amount range in a food system, raw materials are natural, cost is low, biocompatibility is good, preparation parameters are easy to control, large-scale production is facilitated, and the fiber can be widely applied to multiple fields such as food.

Description

Technical Field

[0001] This invention relates to the field of biomaterials technology, specifically to a method for modifying protein nanofibers with high foaming properties. Background Technology

[0002] Proteins, as natural macromolecules, have wide applications in many fields such as food, medicine, and cosmetics. Their functional properties, especially their foaming and emulsifying properties, directly affect the quality and performance of related products. For example, in the food industry, the foaming properties of proteins are used to make cakes, ice cream, and other products with a light and airy texture, while their emulsifying properties contribute to the stability of food systems.

[0003] Compared to natural proteins, food-grade protein fibers possess biocompatibility and non-toxicity, and exhibit improved functional properties, including antioxidant and antibacterial activities. They are considered a promising modified milk protein raw material for future food processing. Currently, various animal and plant proteins have been shown to transform into nanofibers under acidic conditions and denaturing temperatures, indicating that protein fibrillation is a common characteristic of food-grade proteins. Research generally suggests that protein aggregates exhibit diverse microstructures and characteristic morphologies, among which fibrillation self-assembly has attracted widespread attention. Fibers formed from the self-assembly of food-derived proteins have many potential applications in food science and other fields. Studies have shown that, due to their high aspect ratio, excellent mechanical properties, and various tunable functional groups on the surface of proteins, transforming food-grade proteins into nanofibers is a promising modification strategy that can broaden the functional properties of proteins, such as emulsification. Patent publication (announcement) number CN115948812B proposes a method for preparing mung bean globulin amyloid fibers with excellent emulsifying properties. This method first prepares defatted mung bean powder, then obtains mung bean globulin. The mung bean globulin is then dispersed in deionized water, hydrated by stirring at room temperature, adjusted to extremely acidic pH, centrifuged and filtered, and then heated in an oil bath at 95°C for 4 hours with continuous magnetic stirring. Finally, it is cooled in an ice bath to obtain mung bean globulin amyloid fibers. After treatment with this method, the emulsifying activity of the amyloid-fibrillated mung bean globulin is improved by 37.25%-79.33%, and the emulsifying stability is improved by 125.66%-153.44%. However, this method also has certain limitations. It only focuses on improving emulsifying performance and lacks consideration for the foaming performance of protein nanofibrils. In applications such as baked goods and dairy products in the food industry, both foaming and emulsifying properties are equally important and must be considered to meet diverse product requirements. Summary of the Invention

[0004] The purpose of this invention is to provide a method for modifying protein nanofibrils with high foaming properties, so as to improve the emulsification properties and other functional characteristics of proteins, and to develop a method for modifying protein nanofibrils with high foaming properties.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for modifying protein nanofibrils with high foaming properties includes the following steps:

[0007] S10 Preparation of chickpea protein isolate solution: Defatted chickpea powder and deionized water were mixed at a ratio of 1:10 (w / v), the pH was adjusted to 10, and the mixture was magnetically stirred at 25°C for 2 hours; then centrifuged at 4°C and 8000g for 30 min, the supernatant was collected, the pH was adjusted to 4.9 with 2 mol / L HCl, and hydrated overnight at 4°C; the precipitate was obtained by centrifugation again at 4°C and 8000g for 30 min, washed twice with deionized water, and then freeze-dried to obtain chickpea protein isolate;

[0008] S20 Protein Fibrinization Treatment: The chickpea protein isolate obtained in step S10 was dissolved in deionized water to prepare a 3.0% (w / v) solution. After magnetic stirring for 30 min, the pH was adjusted to 2.0 with 2 mol / L HCl and hydrated overnight at 4°C. Then, the solution was centrifuged at 8000g for 20 min at 4°C. The supernatant was transferred to a centrifuge tube with a sealed cap and placed in a magnetically stirred water bath with a rotor. The tube was heated at 80±2.0°C for 2-14 h. After heating, the tube was immediately placed in an ice-water bath to cool to room temperature to obtain highly foamy protein nanofibrils.

[0009] Preferably, the freeze-drying conditions in step 10 are: vacuum degree ≤ 10 Pa, temperature ≤ -40℃, and drying time 12-24 h.

[0010] Preferably, the heating time in step S20 is 8-12 hours.

[0011] Preferably, the stirring rate of the magnetic stirring water bath in step S20 is 300-500 r / min.

[0012] Preferably, the highly foamable protein nanofibers obtained in step S30 have a diameter of 50-200 nm and a length of 1-10 μm, and are added to the food system at an amount of 0.1-5.0 wt%.

[0013] Preferably, the foaming capacity FC of the fibrin solution is determined after treatment with a high-speed dispersion homogenizer, and the formula is: FC=V0 / V×100%, where V0 is the foam volume after 0 minutes of homogenization and V is the original volume of the sample.

[0014] Preferably, the foaming stability FS of the fibrin solution is determined by measuring the change in foam volume after standing for 10 minutes, using the formula: FS = V 10 / V×100%, where V 10 This represents the volume of foam 10 minutes after homogenization.

[0015] Preferably, the emulsifying activity index (EAI) of the fibrous protein solution is determined by measuring the absorbance at 500 nm after homogenization with soybean oil, using the following formula:

[0016]

[0017] Where D is the dilution factor; C is the protein concentration (g / mL); φ is the oil volume fraction (v / v); and A0 is the absorbance at 0 min after homogenization.

[0018] Preferably, the emulsification stability index (ESI) of the fibrin solution is determined by measuring the change in absorbance after standing for 20 minutes, using the following formula: A 20 The absorbance is measured 20 minutes after homogenization.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] The protein nanofibrils modification method with high foaming properties provided by this invention exhibits significant and detailed beneficial effects in multiple dimensions, as follows:

[0021] 1. At the fiber structure regulation level, this method achieves precise control of protein nanofibrils through multi-step synergistic effects. Starting with the preparation of chickpea protein isolate, repeated centrifugation, washing, and freeze-drying ensure the purity and structural stability of the initial protein, laying a high-quality foundation for subsequent fibrillation. During the protein fibrillation process, strict control of solution concentration, pH value, hydration time, and heating temperature and duration promotes the orderly folding and aggregation of protein molecules, forming nanofibrils with specific microstructures. Ultimately, uniform fibers with stable lengths of 50-200 nm and stable diameters of 10-40 nm are obtained. Fibers of this size not only have a large specific surface area, providing more active sites, but their uniformity also ensures stable dispersion in the application system, avoiding performance fluctuations caused by excessive size differences.

[0022] 2. Regarding performance enhancement, this method endows protein nanofibers with excellent foaming properties. Through optimized fibrillation treatment, the spatial structure of protein molecules undergoes a favorable transformation, resulting in nanofibers with good elasticity and extensibility. These fibers can quickly encapsulate air, forming a large amount of uniform and stable foam, significantly improving foaming capacity. Simultaneously, the enhanced interaction between fibers forms a tough interfacial film, effectively delaying foam breakage and liquid separation, significantly improving foaming stability. Even after standing for 10 minutes, the foam volume maintains a high proportion. Furthermore, this method improves foaming performance without sacrificing the emulsifying properties of the protein. The protein nanofibers can rapidly adsorb and align at the oil-water interface, reducing interfacial tension and forming a stable emulsion. Both the emulsifying activity index and emulsifying stability index remain at good levels, meeting the emulsifying requirements of the food and other industries.

[0023] 3. In terms of application adaptability, the highly foamable protein nanofibers prepared by this method exhibit excellent practicality and flexibility. The clearly defined addition range (0.1-5.0 wt%) in food systems allows for flexible adjustments based on the characteristics and needs of different food products. Whether used to improve the fluffiness of baked goods or to enhance the taste and stability of dairy products, it is suitable for various production scenarios. Furthermore, the raw material used in the entire preparation process is natural chickpea protein, which is widely available, low in cost, and has good biocompatibility and biodegradability, avoiding the potential safety hazards of chemically synthesized additives. This aligns with the modern food industry's trend towards natural, healthy, and green ingredients. In addition, the parameters in the preparation process are easy to control and scale up, making the transition from laboratory-scale trials to large-scale industrial production relatively easy, which is conducive to industrial application and provides a high-performance, safe, and reliable protein-based functional ingredient for related industries.

[0024] In summary, this invention, through systematic process optimization, has achieved a comprehensive improvement in the structure, performance, and application of protein nanofibers, providing strong support for their wide application in multiple fields such as food, medicine, and cosmetics. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are explained in detail together with the embodiments of the invention, but do not constitute a limitation thereof.

[0026] Figure 1 The images shown are atomic force micrographs and length distribution histograms of the samples from this invention.

[0027] Figure 2 This is a relative proportion diagram of the infrared secondary structure of the sample of the present invention;

[0028] Figure 3This is a bar chart showing the foaming capacity and foaming stability of the samples from this invention.

[0029] Figure 4 This is a bar chart showing the emulsification activity index and emulsification stability index of the samples from this invention. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] This invention provides a method for modifying highly foaming protein nanofibers:

[0032] (1) Mix defatted chickpea powder with deionized water at a ratio of 1:10 (w / v), adjust the pH to 10, and stir magnetically for 2 hours at room temperature of 25°C.

[0033] (2) Then the mixture was centrifuged at 8000g at 4℃ for 30min, and the pH of the supernatant was adjusted to 4.9 with 2mol / LHCl. It was then left at 4℃ overnight to ensure full hydration.

[0034] (3) Centrifuge the mixture at 8000g at 4℃ for 30min to obtain a precipitate, then wash the precipitate twice with deionized water, collect the precipitate, and then freeze-dry it to obtain chickpea protein isolate solution.

[0035] (4) After the protein solution is fiberized, chickpea protein nanofibers are obtained, which are then freeze-dried for later use.

[0036] Chickpea protein isolate was dissolved in deionized water to prepare a 3.0% (w / v) solution, and magnetically stirred for 30 min. The pH was adjusted to 2.0 with 2 mol / L HCl, and the solution was left to stand overnight at 4°C to ensure full hydration. The solution was then centrifuged at 8000g for 20 min at 4°C. The supernatant was collected. The solution was then transferred to centrifuge tubes with sealed caps, and a rotor was placed inside (to ensure uniform heating). The samples were placed in a magnetically stirred water bath and heated at 80±2.0°C for 2, 4, 6, 8, 10, 12, and 14 h, respectively. Immediately after heating, the samples were removed and cooled to room temperature in an ice-water bath. The samples that did not undergo heating treatment (0 h) were considered the control group.

[0037] 1. Fourier transform infrared spectroscopy

[0038] The freeze-dried chickpea protein isolate and chickpea protein nanofiber samples were stored in a desiccator for later use. 1.0 mg of the sample was accurately weighed and mixed with 100 mg of spectroscopically pure potassium bromide powder in an agate mortar for 15 minutes until homogeneous. The mixed powder was placed in a tableting mold to prepare transparent sheets. Testing was performed using a Vertex 70 Fourier transform infrared spectrometer. The scanning range was set to 4000-400 cm⁻¹. -1 The resolution is 4cm. -1 The number of scans was 32. Each sample was measured in triplicate, and baseline correction was performed against an air background. The raw spectra were smoothed and baseline corrected using PeakFitv 4.12 software, such as... Figure 2 As shown, the secondary structure content of the sample was obtained through analysis.

[0039] 2. Foaming performance test

[0040] (1) Dissolve chickpea protein isolate and chickpea protein nanofibers in deionized water at a certain concentration and adjust the pH.

[0041] (2) The sample was processed using a high-speed dispersion homogenizer to obtain a foam solution.

[0042] Chickpea protein isolate and chickpea protein nanofibers were dissolved in deionized water at pH 2.0 to prepare a sample solution with a concentration of 7 mg / mL. All solutions were equilibrated at 25°C for 30 minutes to ensure complete dissolution. 15 mL of the sample solution was transferred to a 50 mL centrifuge tube and homogenized using a high-speed homogenizer (FJ200-SH) at 15000 rpm for 1 minute. Immediately after homogenization (0 minutes), the sample was transferred to a 25 mL graduated glass cylinder, and the initial foam volume (V0) was accurately recorded. Figure 3 As shown in the figure. The sample was then allowed to stand, and the foam volume (V10) was measured again after 10 minutes.

[0043] Foaming capacity (FC) and foaming stability (FS) are calculated using the following formulas:

[0044]

[0045] Where V is the original volume of the sample, V0 is the foam volume after homogenization for 0 min, and V10 is the foam volume after homogenization for 10 min.

[0046] 3. Emulsification performance test

[0047] (1) Dissolve chickpea protein isolate and chickpea protein nanofibers in deionized water at a certain concentration and adjust the pH.

[0048] (2) Mix with a certain amount of soybean oil and process the sample using a high-speed dispersion homogenizer;

[0049] (3) Dilute the sample solution with SDS solution;

[0050] (4) Measure the absorbance of the sample solution at 500 nm.

[0051] Determination of Emulsifying Activity Index (EAI) and Emulsifying Stability Index (ESI):

[0052] Accurately weigh chickpea protein isolate and chickpea protein nanofiber samples, and prepare 10 mg / mL sample solutions respectively. Mix 5 mL of sample solution with 10 mL of food-grade soybean oil, and homogenize using a high-speed homogenizer (FJ200-SH, Shanghai) at 10,000 rpm for 2 min to form a primary emulsion. Take 10 μL of the freshly prepared emulsion and immediately dilute it with 1 wt% sodium dodecyl sulfate (SDS) solution (dilution factor: 200-fold), and vortex thoroughly to ensure uniform dispersion. Immediately transfer the diluted emulsion sample (0 min) to a 96-well plate, and measure the initial absorbance (A0) at 500 nm using a microplate reader. Subsequently, allow the remaining sample to stand for 20 min, and measure the absorbance at 500 nm again (A0). 20 ),like Figure 4 As shown. EAI and ESI are calculated using the following formulas:

[0053]

[0054] Where D is the dilution factor; C is the protein concentration (g / mL); φ is the oil volume fraction (v / v); A0 is the absorbance at 0 min after homogenization, and A20 is the absorbance at 20 min after homogenization.

[0055] The protein modification method proposed in this invention first induces the formation of β-sheet-enriched protofibrillary structures in proteins under conditions of pH 2.0 and 80℃, achieving dual optimization of protein fiber structure and functional properties. This method not only avoids the use of chemical modifiers, but more importantly, increases the β-sheet content by 17.4%. The foaming ability of unmodified chickpea protein isolate is 27.5%, and its foaming stability is 76.6%. The foaming ability of chickpea protein nanofibers is measured to be 34.0%, and their foaming stability is 87.6%. Compared with chickpea protein isolate, chickpea protein nanofibers show improvements in foaming ability and foaming stability of 23.6% and 14.4%, respectively. The emulsifying activity of unmodified chickpea protein isolate is 4.91m. 2 / g, emulsifying stability was 41.82%, and the emulsifying activity of chickpea protein nanofibers was determined to be 6.07m. 2 / g, with an emulsification stability of 88.94%. Compared with chickpea protein isolate, chickpea protein nanofibers showed improved emulsification activity and emulsification stability by 23.6% and 112.7%, respectively. Compared with chickpea protein isolate, the emulsification performance of chickpea protein nanofibers obtained by this method was significantly improved, significantly enhancing the functional properties of the protein while ensuring food safety.

[0056] Example 1

[0057] S10 Preparation of chickpea protein isolate solution: Defatted chickpea powder and deionized water were mixed in proportion, and the pH was adjusted to 10. The mixture was then magnetically stirred at 25°C for 2 hours. After centrifugation at 4°C and 8000g for 30 minutes, the supernatant was adjusted to pH 4.9 with 2 mol / L HCl and hydrated overnight at 4°C. After centrifugation again at 4°C and 8000g for 30 minutes, the precipitate was washed twice with deionized water and then freeze-dried for 18 hours under vacuum ≤10Pa and temperature ≤-40°C to obtain chickpea protein isolate.

[0058] S20 protein fibrillation treatment: Chickpea protein isolate was dissolved in deionized water to prepare a 3.0% (w / v) solution. After magnetic stirring for 30 min, the pH was adjusted to 2.0 with 2 mol / L HCl and hydrated overnight at 4℃. After centrifugation at 8000g for 20 min at 4℃, the supernatant was transferred to a centrifuge tube with a sealed cap and placed in a water bath with a rotor and magnetic stirring at a stirring rate of 400 r / min. The mixture was heated at 80±2.0℃ for 8 h and immediately cooled to room temperature in an ice water bath to obtain highly foamy protein nanofibrils.

[0059] Example 2

[0060] S10 Preparation of chickpea protein isolate solution: Same as in Example 1, freeze-drying time is 12h.

[0061] S20 protein fibrosis treatment: The solution preparation and pretreatment are the same as in Example 1. The magnetic stirring water bath is stirred at a rate of 300 r / min and heated at 80±2.0℃ for 12 h. The remaining steps are the same to obtain highly foamable protein nanofibrils.

[0062] Example 3

[0063] S10 Preparation of chickpea protein isolate solution: Same as in Example 1, freeze-drying time is 24h.

[0064] S20 protein fibrillation treatment: The solution preparation and pretreatment were the same as in Example 1. The magnetic stirring water bath was stirred at a speed of 500 r / min and heated at 80±2.0℃ for 10 h. The remaining steps were the same to obtain chickpea protein nanofibrils.

[0065] Comparative Example 1 (Shortening the fiberization heating time)

[0066] S10 Preparation of chickpea protein isolate solution: Same as in Example 1.

[0067] S20 protein fibrillation treatment: Except for the heating time being changed to 1 hour, the other steps are the same as S20 in Example 1, resulting in an incompletely fibrillated protein product.

[0068] S30 high-speed dispersion homogenization post-treatment: Same as S30 in Example 1, the foaming ability FC and foaming stability FS of the obtained product are significantly lower than those of Examples 1-3, and the emulsification activity index EAI and emulsification stability index ESI are also poor.

[0069] Comparison table of key parameters and results for the three embodiments above:

[0070] project Example 1 Example 2 Example 3 Comparative Example 1 freeze-drying time 18h 12h 24h 18h Magnetic stirring water bath stirring speed 400r / min 300r / min 500r / min 400r / min Heating time 8h 12h 10h 1h Addition amount in food system 2.0wt% 1.0wt% 3.0wt% Not mentioned Foaming ability and stability good good good Significantly lower than Examples 1-3 Emulsifying activity index and emulsifying stability index Not mentioned Not mentioned Not mentioned Poor

[0071] A comparison of key data from the above embodiments and comparative examples demonstrates that the present invention has several significant beneficial effects:

[0072] 1. Regarding fiber size control, Examples 1-3 yielded uniform protein nanofibers with diameters of 10-40 nm and lengths of 50-200 nm.

[0073] 2. Regarding foaming performance, Examples 1-3 all exhibited good foaming ability and stability. In contrast, Comparative Example 1, due to its fiberization heating time of only 1 hour (far lower than the 8-12 hours of the Examples), showed a significant decrease in foaming ability (FC) and foaming stability (FS). This indicates that a suitable heating time (8-12 hours) is key to ensuring sufficient protein fiberization and improving foaming performance.

[0074] 3. Regarding application adaptability, Examples 1-3 clearly define the addition amount (1.0-3.0 wt%) in food systems, and the fiber size is uniform and controllable, which can better adapt to the needs of different food systems. In contrast, the comparative examples do not specify the addition amount and the fiber size is unstable, which significantly limits their application.

[0075] 4. In addition, although the specific values ​​of the emulsifying activity index (EAI) and the emulsifying stability index (ESI) are not directly presented in the table, the emulsifying performance of Comparative Example 1 is poor, and the related defects are not mentioned in the examples. It can be inferred that the present invention, through reasonable fiberization treatment and high-speed dispersion homogenization post-treatment, can maintain good emulsifying performance while ensuring high foaming properties, thus broadening its application scenarios in the food industry (such as baking, dairy products and other fields that require both foaming and emulsifying functions).

[0076] In summary, this invention achieves controllable size, high foaming properties, and good application adaptability of protein nanofibrils through optimized chickpea protein isolate preparation and precise post-processing (pH, temperature, and time control), which has significant advantages over unmodified methods.

[0077] The protein nanofibrils modification method with high foaming properties provided by this invention exhibits significant and detailed beneficial effects in multiple dimensions, as follows:

[0078] At the fiber structure regulation level, this method achieves precise control over protein nanofibrils through multi-step synergistic action. Starting with the preparation of chickpea protein isolate, repeated centrifugation, washing, and freeze-drying ensure the purity and structural stability of the initial protein, laying a high-quality foundation for subsequent fibrillation. During protein fibrillation, strict control of solution concentration, pH, hydration time, and heating temperature and duration promotes the orderly folding and aggregation of protein molecules, forming nanofibrils with specific microstructures. Ultimately, uniform fibers with stable lengths ranging from 50-200 nm and diameters from 10-40 nm are obtained. Fibers of this size not only have a large specific surface area, providing more active sites, but their uniformity also ensures stable dispersion in application systems, avoiding performance fluctuations caused by excessive size differences.

[0079] In terms of performance enhancement, this method endows protein nanofibrils with excellent foaming properties. Through optimized fibrillation treatment, the spatial structure of protein molecules undergoes a favorable transformation, resulting in nanofibrils with good elasticity and extensibility. These nanofibrils can quickly encapsulate air, forming a large amount of uniform and stable foam, significantly improving the foaming capacity (FC). Simultaneously, the enhanced interactions between fibers form a tough interfacial film, effectively delaying foam rupture and liquid separation, significantly improving foaming stability (FS). Even after standing for 10 minutes, the foam volume maintains a high proportion. Furthermore, this method improves foaming performance without sacrificing the emulsifying properties of the protein. The protein nanofibrils can rapidly adsorb and align at the oil-water interface, reducing interfacial tension and forming a stable emulsion. Both the emulsifying activity index (EAI) and the emulsifying stability index (ESI) remain at good levels, meeting the emulsifying requirements of the food and other industries.

[0080] In terms of application adaptability, the highly foamable protein nanofibers prepared by this method exhibit excellent practicality and flexibility. The clearly defined addition range (0.1-5.0 wt%) in food systems allows for flexible adjustments based on the characteristics and needs of different food products. Whether used to improve the fluffiness of baked goods or to enhance the taste and stability of dairy products, it is suitable for various production scenarios. Furthermore, the raw material used in the entire preparation process is natural chickpea protein, which is widely available, low in cost, and has good biocompatibility and biodegradability, avoiding the potential safety hazards of chemically synthesized additives. This aligns with the modern food industry's trend towards natural, healthy, and green ingredients. In addition, the parameters in the preparation process are easy to control and scale up, making the transition from laboratory-scale trials to large-scale industrial production relatively easy, which is conducive to industrial application and provides a high-performance, safe, and reliable protein-based functional ingredient for related industries.

[0081] In summary, this invention, through systematic process optimization, has achieved a comprehensive improvement in the structure, performance, and application of protein nanofibers, providing strong support for their wide application in multiple fields such as food, medicine, and cosmetics.

[0082] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for modifying protein nanofibers with high foaming properties, characterized in that: Includes the following steps: S10 Preparation of chickpea protein isolate solution: Defatted chickpea powder and deionized water were mixed at a ratio of 1:10 (w / v), the pH was adjusted to 10, and the mixture was magnetically stirred at 25°C for 2 hours; then centrifuged at 4°C and 8000g for 30 min, the supernatant was collected, the pH was adjusted to 4.9 with 2 mol / L HCl, and hydrated overnight at 4°C; the precipitate was obtained by centrifugation again at 4°C and 8000g for 30 min, washed twice with deionized water, and then freeze-dried to obtain chickpea protein isolate; S20 Protein Fibrinization Treatment: The chickpea protein isolate obtained in step S10 was dissolved in deionized water to prepare a 3.0% (w / v) solution. After magnetic stirring for 30 min, the pH was adjusted to 2.0 with 2 mol / L HCl and hydrated overnight at 4°C. Then, the solution was centrifuged at 8000g for 20 min at 4°C. The supernatant was transferred to a centrifuge tube with a sealed cap and placed in a magnetically stirred water bath with a rotor. The tube was heated at 80±2.0°C for 2-14 h. After heating, the tube was immediately placed in an ice-water bath to cool to room temperature to obtain highly foamy protein nanofibrils.

2. The method for modifying protein nanofibers with high foaming properties according to claim 1, characterized in that: The freeze-drying conditions described in step 10 are: vacuum degree ≤ 10 Pa, temperature ≤ -40℃, and drying time 12-24 h.

3. The method for modifying protein nanofibers with high foaming properties according to claim 1, characterized in that: The heating time in step S20 is 8-12 hours.

4. The method for modifying protein nanofibers with high foaming properties according to claim 1, characterized in that: The stirring speed of the magnetic stirring water bath in step S20 is 300-500 r / min.

5. The method for modifying protein nanofibers with high foaming properties according to claim 1, characterized in that: The highly foamable protein nanofibers obtained in step S30 have a diameter of 50-200 nm and a length of 1-10 μm, and are added to the food system at a rate of 0.1-5.0 wt%.

6. The method for modifying protein nanofibers with high foaming properties according to claim 1, characterized in that: The foaming capacity FC of the fibrin solution was determined after treatment with a high-speed dispersion homogenizer. The formula is: FC = V0 / V × 100%, where V0 is the foam volume after 0 minutes of homogenization and V is the original volume of the sample.

7. The method for modifying protein nanofibers with high foaming properties according to claim 1, characterized in that: The foaming stability FS of the fibrin solution was determined by measuring the change in foam volume after standing for 10 minutes, and the formula is: FS = V 10 / V×100%, where V 10 This represents the volume of foam 10 minutes after homogenization.

8. The method for modifying protein nanofibers with high foaming properties according to claim 1, characterized in that: The emulsification activity index (EAI) of the fibrin solution was determined by measuring the absorbance at 500 nm after homogenization with soybean oil, using the following formula: Where D is the dilution factor; C is the protein concentration (g / mL); φ is the oil volume fraction (v / v); and A0 is the absorbance at 0 min after homogenization.

9. The method for modifying protein nanofibers with high foaming properties according to claim 8, characterized in that: The emulsification stability index (ESI) of the fibrin solution was determined by measuring the change in absorbance after standing for 20 minutes, using the following formula: A 20 The absorbance is measured 20 minutes after homogenization.

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