A method for improving the foaming properties of rapeseed protein and products thereof

Abstract

The application discloses a method for improving the foaming property of rapeseed protein and a product thereof, and comprises the following steps: adjusting the pH of a rapeseed protein solution to 1.5-2.5, water bath magnetic stirring, cooling to room temperature, and adjusting the pH to 7.5-9.0 again, so that the rapeseed protein with high foaming property is obtained. The method can effectively improve the foaming property of the rapeseed protein, and is helpful to the application of the rapeseed protein as a food ingredient in a food system. The experimental conditions of acid and heat are relatively easy to achieve in daily life, and the method can be realized without large instruments, and is simple to operate, safe, and does not need the addition of biological agents such as enzymes. The method has the advantages of short processing time, low production cost, few operation procedures, and can be industrialized and continuously produced. The emulsifying activity and emulsifying stability of the rapeseed protein are greatly improved under specific acid and heat induction time.

Description

Technical Field

[0001] This invention relates to a method for improving the foaming properties of rapeseed protein and its products, belonging to the field of food processing. Background Technology

[0002] Protein is an essential macronutrient for human nutrition and possesses outstanding functional properties, making it a key ingredient in regulating food quality. Traditionally, animal-derived proteins, such as meat, milk, and poultry protein, have been the preferred choice. However, due to the low resource efficiency of converting plant matter into animal-derived protein (approximately 7:1), the large-scale consumption of animal-derived protein inevitably exacerbates current problems such as climate change, water and energy shortages caused by global population growth. Therefore, finding and preparing plant proteins with high functional properties to replace animal proteins is a significant challenge. Rapeseed protein, derived from rapeseed oilseed meal, has a good amino acid balance, high bioavailability, and high nutritional value, making it a high-quality protein resource that has received widespread attention in recent years. Rapeseed protein also has good emulsifying and foaming properties, making it suitable for use in the food industry to improve product quality and processing efficiency.

[0003] Foaming properties arise because surfactants reduce the surface tension of liquids and form an oriented molecular adsorption layer at the gas-liquid interface. Proteins, being amphiphilic molecules, can spontaneously migrate to the gas-liquid interface and form a highly viscoelastic film. This interfacial system is more stable than interfaces formed by low-molecular-weight surfactants, thus making it a good foaming agent. As demands for the functional, nutritional, and sensory properties of food continue to increase, the application of proteins is increasingly insufficient to meet the needs of modern food development and processing. Therefore, protein modification technology has become an important tool for achieving the desired quality of proteins.

[0004] Existing methods for modifying rapeseed protein mainly involve enzymatic hydrolysis, resulting in foaming properties of 20-30% and foam stability of 10-90%. These methods suffer from drawbacks such as high enzyme dosage, long hydrolysis times, and limited improvement in foaming properties, making them unsuitable for continuous industrial production. Therefore, finding a rapid and convenient method suitable for continuous industrial production is crucial. Currently, no research has been reported on using acid-heat induction to improve the foaming properties of rapeseed protein. Summary of the Invention

[0005] Purpose of the invention: The technical problem to be solved by the present invention is to provide a simple method and product for improving the foaming properties of rapeseed protein that does not require the addition of enzymes or other biological agents.

[0006] Technical solution: To solve the above technical problems, the present invention provides a method for improving the foaming properties of rapeseed protein, comprising the following steps: adjusting the pH of the rapeseed protein solution to 1.5-2.5, stirring magnetically in a water bath, cooling to room temperature, and adjusting the pH again to 7.5-9.0, thereby obtaining rapeseed protein with high foaming properties.

[0007] Preferably, the pH of the rapeseed protein solution is adjusted to be 1.5 to 2.0.

[0008] Preferably, the pH value after the pH is readjusted is 7.5 to 8.5.

[0009] Furthermore, the pH value after the pH is readjusted is 8.0 to 8.5.

[0010] The concentration of the rapeseed protein solution is 1–6 mg / mL.

[0011] The temperature of the water bath magnetic stirring is 80-95℃.

[0012] The water bath magnetic stirring time is 2 to 8 hours.

[0013] Preferably, the rapeseed protein solution concentration is 2 mg / mL, and the water bath stirring time is 4 hours. At this time, the rapeseed protein has good foaming properties and foam stability, and the foam stability is maintained at a high level (around 90%).

[0014] The method for preparing the rapeseed protein solution includes the following steps: dissolving rapeseed protein powder, magnetically stirring, ultrasonically dissolving, centrifuging, and taking the supernatant to obtain the rapeseed protein solution.

[0015] The solvent used to dissolve the rapeseed protein powder is HCl.

[0016] The present invention also provides rapeseed protein with high foaming properties prepared by the method.

[0017] The rapeseed protein has a foaming property of 126.8%–157.5% and a foam stability of 89.8%–96.9%.

[0018] Mechanism of this invention: When a protein is exposed to an acidic environment and subjected to heat treatment, it is hydrolyzed and reassembled into a nanofiber structure rich in β-sheets. Compared with unmodified protein, converting protein into amyloid-like nanofibers improves its foaming properties.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: 1. It can effectively improve the foaming properties of rapeseed protein, which is conducive to the application of rapeseed protein as a food ingredient in food systems; 2. The acid and heat experimental conditions are easy to achieve in daily life, can be realized without large instruments, are simple to operate, do not require the addition of enzymes or other biological agents, and are relatively safe; 3. The processing time is short, the production cost is low, the operation steps are few, and it can be industrialized for continuous production; 4. Under a specific acid and heat induction time, the emulsifying activity and emulsifying stability of rapeseed protein are greatly improved. Attached Figure Description

[0020] Figure 1 The foaming properties and foam stability of rapeseed protein solutions under different acid-heat induction times are as follows: Figure 1 A represents the foaming properties of a 2 mg / mL rapeseed protein solution under different acid-heat induction times; Figure 1 B represents the foam stability of a 2 mg / mL rapeseed protein solution under different acid-heat induction times; Figure 1 C is a photo of rapeseed protein after 30 seconds of foaming; Figure 1 D is a photo of rapeseed protein after 30 minutes of foaming;

[0021] Figure 2 The average particle size, PDI, and potential of rapeseed protein solutions under different acid-heat induction times (induction pH 2.0; induction temperature 90℃; sample pH at foaming time 8.0): Figure 2 A represents the average particle size and PDI of a 2 mg / mL rapeseed protein solution under different acid-heat induction times; Figure 2 B represents the potential of a 2 mg / mL rapeseed protein solution under different acid-heat induction times;

[0022] Figure 3 The foaming properties and foam stability of rapeseed protein solutions of different concentrations under different acid-heat induction times are shown below: Figure 3 A represents the foaming properties of rapeseed protein solutions of different concentrations under different acid-heat induction times; Figure 3 B represents the foam stability of rapeseed protein solutions of different concentrations under different acid-heat induction times;

[0023] Figure 4 The foaming properties and foam stability of rapeseed protein solutions under different acid-heat induced pH conditions are as follows: Figure 4 A represents the foaming properties of rapeseed protein solution under different acid-heat induced pH conditions; Figure 4 B represents the foam stability of rapeseed protein solution under different acid-heat induced pH conditions;

[0024] Figure 5 The foaming properties and foam stability of rapeseed protein solutions under different acid-heat induction temperatures are as follows: Figure 5 A represents the foaming properties of rapeseed protein solution at different acid-heat induction temperatures; Figure 5 B represents the foam stability of rapeseed protein solution under different acid-heat induction temperatures;

[0025] Figure 6 The foaming properties and foam stability of rapeseed protein solutions at different pH values ​​were analyzed: Figure 6 A represents the foaming properties of rapeseed protein solution at different pH values ​​in different foaming samples; Figure 6 B represents the foam stability of rapeseed protein solution at different pH values ​​in different foaming samples;

[0026] Figure 7 The emulsifying activity index of 2 mg / mL rapeseed protein solution under different acid-heat induction times and the emulsifying activity index of rapeseed protein solution after 1 h under different acid-heat induction times (which can reflect its emulsifying stability). Detailed Implementation

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0028] FW100 High-Speed ​​Universal Crusher: Tianjin Tais Instrument Co., Ltd.; 84-1 Magnetic Stirrer: Shanghai Meiyingpu Instrument Manufacturing Co., Ltd.; GL-21M High-Speed ​​Refrigerated Centrifuge: Shanghai Naissenkalan Industrial Co., Ltd.; FreeZone 2.5L Benchtop Freeze Dryer: Labconco, USA; AB150 Benchtop pH Meter: Thermo Fisher Scientific; Nano-ZS90 Nanoparticle Size Analyzer: Malvern Instruments, UK; KH5200B Ultrasonic Cleaner: Kunshan Hechuang Ultrasonic Instrument Co., Ltd.; SMDJ-1005-4S Intelligent Thermostatic Bath: Nanjing Shunma Instrument Equipment Co., Ltd.; XHF-DY High-Speed ​​Disperser: Ningbo Xinzhi Biotechnology Co., Ltd.; U-3900 Ultraviolet Spectrophotometer: Hitachi, Japan.

[0029] Petroleum ether: Sinopharm Chemical Reagent Co., Ltd.; BCA protein concentration assay kit: Beijing Solarbio Science & Technology Co., Ltd.; Sodium dodecyl sulfate (SDS): Shanghai Aladdin Biochemical Technology Co., Ltd.

[0030] Example 1: Effect of different acid-heat induction times on foaming properties and foam stability

[0031] Rapeseed protein powder was prepared according to the method of patent application (application number: 2022113446585) and stored in a -20℃ refrigerator for later use.

[0032] Weigh an appropriate amount of rapeseed protein powder and dissolve it directly in 0.01M HCl. Stir magnetically at room temperature (300 rpm for 30 min), then place in an ultrasonic cleaner for 30 min to aid dissolution. Centrifuge at 10,000 × g for 20 min at 4℃. After centrifugation, collect the supernatant to obtain the rapeseed protein solution. Determine the protein concentration of the obtained rapeseed protein solution using a BCA protein concentration assay kit. Dilute the rapeseed protein solution to 2 mg / mL with ultrapure water, adjust the pH to 2.0 with 0.1M HCl solution, and then place it in a magnetically stirred water bath at 90℃ for 0, 2, 4, 6, and 8 h for acid-thermal induction. After induction, allow the solution to cool to room temperature and adjust the pH to 8.0 to obtain the rapeseed protein isolate. Store it at 4℃.

[0033] Determination of foaming properties and foam stability: Rapeseed protein isolate was placed in a 100 mL tall beaker and foamed using a high-speed disperser at 5000 rpm for 2 min. Immediately afterwards, the rapeseed protein isolate and foam were transferred to a 50 mL graduated cylinder, and the foam volume (V0) was recorded. After standing at room temperature for 30 min, the foam volume (V0) was recorded again. 30 ), the results are shown Figure 1 The formulas for calculating foaming property (FC) and foam stability (FS) are as follows:

[0034] FC = V0 / 20

[0035] FS = V 30 / V0

[0036] Depend on Figure 1 As can be seen from Figure A, the foaming property of rapeseed protein continuously increases with the increase of acid-heat induction time. The highest foaming property (157.5% ± 1.8%) was observed when the acid-heat induction time was 4 hours, showing a significant effect. However, the foaming property decreased after 4 hours. Figure 1 As can be seen from B, the difference in foam stability under different acid-heat induction times is not significant; and by Figure 1 B~ Figure 1 As shown in Figure D, after 30 seconds and 30 minutes of foaming, the foam height of rapeseed protein under different acid-heat induction times did not change significantly, and its stability remained at a high level (around 90%). Therefore, for cost considerations, an acid-heat induction time of 4 hours can be selected in actual production. Figure 1 Different letters (ac) indicate significant differences (p<0.05).

[0037] Determination of average particle size, polymer dispersibility index (PDI), and potential: The average particle size, PDI, and potential of rapeseed protein solutions under different acid-heat induction times were analyzed and determined using a ZS-Zetasizer Nano. Instrument settings were: He / Ne laser 633 nm, fixed scattering angle of 90°, and temperature of (25±0.1)℃. Results are as follows: Figure 2 As shown, with the increase of acid-heat induction time, the surface charge of the sample remained basically unchanged, while the average particle size first increased and then decreased, and its trend was consistent with the foaming property, indicating that the particle size change has a significant impact on the improvement of rapeseed protein foaming property by acid-heat induction. Figure 2 Different letters (ae) indicate significant differences (p<0.05).

[0038] Example 2: Effect of different rapeseed protein solution concentrations on the foaming properties and foam stability of rapeseed protein

[0039] Rapeseed protein solutions were prepared according to the method in Example 1. The protein content in the rapeseed protein solutions was determined using a BCA kit according to the manufacturer's instructions. The protein solutions were then diluted with ultrapure water to concentrations of 1, 2, 4, and 6 mg / mL, respectively. The pH of the solutions was adjusted to 2.0 with 0.1 M HCl. The sample solutions were then placed in a magnetically stirred water bath and stirred at 90°C for 0, 2, 4, and 6 hours, respectively, to induce acid-thermal induction. After induction, the solutions were allowed to cool to room temperature and the pH was adjusted to 8.0. The samples were then stored at 4°C to obtain rapeseed protein isolate.

[0040] Similarly, the obtained rapeseed protein isolate was placed in a 100 mL tall beaker and sheared at 5000 rpm for 2 min using a high-speed disperser. Immediately afterwards, the rapeseed protein isolate and foam were transferred to a 50 mL graduated cylinder, and the foam volume (V0) was recorded. The modified rapeseed protein solution was allowed to stand at room temperature for 30 min, and the foam volume (V0) was recorded again. 30 ), the results are shown Figure 3 Different letters (ah) indicate significant differences (p<0.05). The formulas for calculating foaming property (FC) and foam stability (FS) are as follows:

[0041] FC = V0 / 20

[0042] FS = V 30 / V0

[0043] Depend on Figure 3It can be seen that with the increase of acid-heat induction time, at a concentration of 1 mg / mL, the foaming property significantly increased from 100% to 125%, while the foam stability remained basically at 95%; at a concentration of 2 mg / mL, the foaming property first increased and then decreased, with the best foaming property (157.5%) at 4 hours, and the foam stability remained basically at 95%; at a concentration of 4 mg / mL, the foaming property remained basically at 150%, but the foam stability significantly decreased from 95% to 80%; at a concentration of 6 mg / mL, although the foaming property increased significantly to 200.8%, the foam stability dropped to 72%. Therefore, considering factors such as cost and foam characteristics, a rapeseed protein concentration of 2 mg / mL and an acid-heat induction time of 4 hours can be selected in actual production.

[0044] Example 3: Effect of different acid-heat induced pH values ​​on the foaming properties and foam stability of rapeseed protein solutions

[0045] Rapeseed protein solution was prepared according to the method in Example 1. The protein content in the rapeseed protein solution was determined using a BCA kit according to the manufacturer's instructions. The protein solution was then diluted to 2 mg / mL with ultrapure water. The pH of the solution was adjusted to 1.5, 2.0, and 2.5 with 0.1 M HCl, respectively. The sample solution was then placed in a magnetically stirred water bath and stirred at 90°C for 4 hours to induce acid-heat treatment. After induction, the solution was allowed to cool to room temperature, and the pH was adjusted to 8.0. The sample was then stored at 4°C to obtain rapeseed protein isolate. Finally, the foaming properties and foam stability of the rapeseed protein solution under different acid-heat induction pH values ​​were determined according to the method in Example 1.

[0046] like Figure 4 As shown, under the same conditions, increasing the acid-heat induced pH from 1.5 to 2.0 significantly increased the foam stability of rapeseed protein; further increasing the pH had no significant effect. Regarding foaming properties, increasing the acid-heat induced pH from 1.5 to 2.0 did not show a significant change; further increasing the pH actually decreased foaming properties. Therefore, in actual production, an acid-heat induced pH of 2.0 can be selected. Figure 4 Different letters (ab) indicate significant differences (p<0.05).

[0047] Example 4: Effect of different acid-heat induction temperatures on the foaming properties and foam stability of rapeseed protein solutions

[0048] Rapeseed protein solution was prepared according to the method in Example 1. The protein content in the rapeseed protein solution was determined using a BCA kit according to the manufacturer's instructions. The protein solution was then diluted to 2 mg / mL with ultrapure water. The pH of the solution was adjusted to 2.0 with 0.1 M HCl. The sample solution was then placed in a magnetically stirred water bath and stirred at 80°C, 90°C, and 95°C for 4 hours respectively to induce acid-heat treatment. After induction, the solution was allowed to cool to room temperature and the pH was adjusted to 8.0. The sample was then stored at 4°C to obtain rapeseed protein isolate. Finally, the foaming properties and foam stability of the rapeseed protein solution under different acid-heat induction pH values ​​were determined according to the method in Example 1.

[0049] like Figure 5 As shown, under the same conditions, the foaming property of the protein solution first increases and then decreases when the acid-heat induction temperature is between 80-95℃, reaching its maximum at 90℃; while the foam stability does not change significantly when the acid-heat induction temperature is between 80-95℃. Therefore, in actual production, an acid-heat induction temperature of 90℃ can be selected. Figure 5 Different letters (ab) indicate significant differences (p<0.05).

[0050] Example 5: Effect of pH on the foaming properties and foam stability of rapeseed protein solution.

[0051] Rapeseed protein solution was prepared according to the method in Example 1. The protein content in the rapeseed protein solution was determined using a BCA kit according to the manufacturer's instructions. The protein solution was then diluted to 2 mg / mL with ultrapure water. The pH of the solution was adjusted to 2.0 with 0.1 M HCl. The sample solution was then placed in a magnetically stirred water bath and heated at 90°C for 4 hours to induce acid-thermal reaction. After induction, the solution was cooled to room temperature, and the pH was adjusted to 7.5, 8.0, 8.5, and 9.0, respectively. The sample was then stored at 4°C to obtain the rapeseed protein isolate. Finally, the foaming properties and foam stability of the rapeseed protein solution under different acid-thermal induction pH values ​​were determined according to the method in Example 1.

[0052] like Figure 6 As shown, under the same conditions, as the pH of the sample increased from 7.5 to 9.0 during foaming, the foaming property of rapeseed protein first increased and then decreased, while the foam stability did not change significantly. Therefore, in actual production, a foaming sample pH of 8.0 can be selected. Figure 6 Different letters (ab) indicate significant differences (p<0.05).

[0053] Example 6: Investigation of the emulsifying properties of rapeseed protein

[0054] Rapeseed protein solution was prepared according to the method in Example 1. The protein content in the rapeseed protein solution was determined using a BCA kit according to the manufacturer's instructions. The protein solution was then diluted to 2 mg / mL with ultrapure water. The pH was adjusted to 2.0 with 0.1 M HCl solution. The sample solution was then placed in a magnetically stirred water bath and heated at 90°C for 0, 8, 24, 42, 48, 60, 66, and 72 hours to induce acid-thermal reaction. After induction, the solution was allowed to cool to room temperature and the pH was adjusted to 8.0. The sample was then stored at 4°C to obtain the rapeseed protein isolate, which was stored at 4°C.

[0055] Take 8 mL of rapeseed protein isolate (2 mg / mL, pH 8.0) into a 20 mL glass bottle, add 2 mL of soybean oil, and stir at 8000 rpm for 1 min using a high-speed disperser to obtain an emulsion. At 0 and 60 min, respectively, take 50 μL of the emulsion and add it to a test tube containing 5 mL of 0.1% SDS solution, mix well, and measure its absorbance at 500 nm. The emulsifying activity index (EAI) is calculated using the following formula:

[0056]

[0057] In the formula: A 500 The absorbance value at 500 nm; Oil phase volume fraction (v / v) C represents the protein concentration (g / ml). In this example, 50 μL of emulsion was added to a test tube containing 5 mL of 0.1% SDS solution, therefore the dilution factor is 100.

[0058] like Figure 7 As shown, after 24 hours of acid-heat induction, the emulsifying activity index and emulsifying stability of rapeseed protein were significantly improved. This indicates that acid-heat induction not only improves the foaming properties of rapeseed protein but also shows promising potential in enhancing its emulsifying properties. Figure 6 Different letters (ah) indicate significant differences (p<0.05). The horizontal axis represents the time of acid-heat induction. In the figure, 0 and 60 min refer to the time when 50 μL of emulsion was added to 5 ml of 0.1% SDS solution in a mixing tube at 0 min and 60 min, respectively, and the absorbance of the diluted sample was measured at 500 nm to calculate the emulsion activity index; the emulsion activity index after 60 min was used to analyze the emulsion stability of the protein sample.

[0059] The effects of different protein treatment methods and pH values ​​after acid-heat induction on the foaming properties and foam stability of rapeseed protein solutions were compared.

[0060] Comparative Example 1: The rapeseed protein powder prepared in Example 1 was dissolved in 0.01M HCl. The protein content in the supernatant was determined using a BCA kit. The protein solution was then diluted with ultrapure water to 2 mg / mL and the pH was adjusted to 8.0. The average particle size, polymer dispersibility index (PDI), potential, foaming properties and foam stability of the rapeseed protein solution were determined according to the method in Example 1.

[0061] Comparative Example 2: The rapeseed protein powder prepared in Example 1 was dissolved in 0.01M HCl and magnetically stirred at room temperature (300 rpm for 30 min). The solution was then placed in an ultrasonic cleaner for 30 min to aid dissolution and centrifuged at 10,000 × g for 20 min at 4°C. After centrifugation, the supernatant was collected, and the protein content was determined using a BCA kit. The protein solution was then diluted to 2 mg / mL with ultrapure water, and the pH was adjusted to 8.0. The average particle size, polymer dispersibility index (PDI), potential, foaming properties, and foam stability of the rapeseed protein solution were determined according to the method in Example 1.

[0062] Comparative Example 3: The rapeseed protein powder prepared in Example 1 was dissolved in 0.01M HCl and magnetically stirred at room temperature (300 rpm for 30 min). The solution was then placed in an ultrasonic cleaner for 30 min to aid dissolution and centrifuged at 10,000 × g for 20 min at 4 °C. After centrifugation, the supernatant was collected, and the protein content was determined using a BCA kit. The protein solution was then diluted to 2 mg / mL with ultrapure water, and the pH was adjusted to 2.0. The sample solution was then placed in a magnetically stirred water bath and acid-heat induced at 90 °C for 4 h. After cooling, the pH was adjusted to 4.0, and the average particle size, polymer dispersibility index (PDI), potential, foaming properties, and foam stability of the rapeseed protein solution were determined according to the method in Example 1.

[0063] Comparative Example 4: The rapeseed protein powder prepared in Example 1 was dissolved in 0.01M HCl and magnetically stirred at room temperature (300 rpm for 30 min). The solution was then placed in an ultrasonic cleaner for 30 min to aid dissolution and centrifuged at 10,000 × g for 20 min at 4 °C. After centrifugation, the supernatant was collected, and the protein content was determined using a BCA kit. The protein solution was then diluted to 2 mg / mL with ultrapure water, and the pH was adjusted to 2.0. The sample solution was then placed in a magnetically stirred water bath and acid-heat induced at 90 °C for 4 h. After cooling, the pH was adjusted to 6.0, and the average particle size, polymer dispersibility index (PDI), potential, foaming properties, and foam stability of the rapeseed protein solution were determined according to the method in Example 1.

[0064] Comparative Example 5: The rapeseed protein powder prepared in Example 1 was dissolved in water and magnetically stirred at room temperature (300 rpm for 30 min). The solution was then placed in an ultrasonic cleaner for 30 min to aid dissolution and centrifuged at 10,000 × g for 20 min at 4 °C. After centrifugation, the supernatant was collected to obtain the rapeseed protein solution. The protein concentration of the obtained rapeseed protein solution was determined using a BCA protein concentration assay kit. The rapeseed protein solution was diluted to 2 mg / mL with ultrapure water and then placed in a magnetically stirred water bath at 90 °C for 4 h. After the reaction was complete and the solution cooled to room temperature, the pH was adjusted to 8.0 to obtain the rapeseed protein isolate, which was stored at 4 °C.

[0065] Comparative Example 6: The rapeseed protein powder prepared in Example 1 was dissolved in 0.01M HCl and magnetically stirred at room temperature (300 rpm for 30 min). The solution was then placed in an ultrasonic cleaner for 30 min to aid dissolution and centrifuged at 10,000 × g for 20 min at 4°C. After centrifugation, the supernatant was collected to obtain the rapeseed protein solution. The protein concentration of the obtained rapeseed protein solution was determined using a BCA protein concentration assay kit. The rapeseed protein solution was diluted to 2 mg / mL with ultrapure water, and the pH was adjusted to 2.0 with 0.1M HCl solution. The solution was then placed in a magnetically stirred water bath and stirred at room temperature for 4 h. The pH was then adjusted to 8.0 to obtain the isolated rapeseed protein material, which was stored at 4°C.

[0066] Table 1

[0067]

[0068]

[0069] As shown in Table 1, if the rapeseed protein powder is dissolved and the supernatant is not collected (Comparative Example 1), the resulting protein solution has a higher PDI (particulate density index). Compared with the solution in Comparative Example 2, the system is less homogeneous and has lower foaming properties, indicating that the presence of impurities reduces the foaming properties of rapeseed protein. The pH value of the sample after acid-heat induction has a significant impact on foaming properties. The particle size and PDI of Comparative Examples 3 and 4 are too large, resulting in large and unevenly dispersed rapeseed protein particles. This prevents the rapeseed protein from rapidly diffusing to the gas-liquid interface and forming a stable interfacial film. Therefore, the foaming properties of rapeseed protein are poor when the pH value of the sample after acid-heat induction is 4.5 and 6.0; and good when the pH value of the sample after acid-heat induction is 8.0.

Claims

1. A method for improving the foaming properties of rapeseed protein, characterized in that, The rapeseed protein solution is prepared by dissolving rapeseed protein powder in HCl solution, stirring magnetically and then ultrasonic dissolving, and centrifuging to obtain supernatant.

2. The method of claim 1, wherein, The preparation method of the rapeseed protein solution comprises: dissolving rapeseed protein powder in HCl solution, stirring magnetically and then ultrasonic dissolving, and centrifuging to obtain supernatant.

3. The rapeseed protein with high foaming property prepared by the method of any one of claims 1-2.

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