Application of green bamboo shoot protein

Abstract

The invention discloses application of green bamboo shoot protein. The green bamboo shoot protein comprises acid extracted protein, salt extracted protein, alcohol extracted protein and alkali extracted protein which are sequentially extracted from green bamboo shoots. The acid extracted protein, the salt extracted protein, the alcohol extracted protein and / or the alkali extracted protein can be used for fluorescence imaging, ion detection and solution pH value testing, and the additional value of the green bamboo shoot protein is remarkably improved. The fluorescence imaging concentration of acid extracted protein, salt extracted protein, alcohol extracted protein and / or alkali extracted protein is smaller than or equal to 5 micrograms per milliliter, and a lower-concentration imaging function is achieved.

Description

Technical Field

[0001] The invention relates to use of green bamboo shoot protein and belongs to the technical field of application of green bamboo shoot protein. Background Art

[0002] In recent years, plant protein has gained wide attention due to its wide sources, sustainability, low cost, vegetarian needs, environmental friendliness and health benefits. At present, the main plant proteins used in the food industry include cereal proteins such as wheat gluten and zein, as well as legume proteins such as soy protein and pea protein. Therefore, it is necessary to develop and utilize new high-quality plant proteins.

[0003] Green bamboo (Bambusa oldhami Munro) is a clumping bamboo species with a long history of cultivation and utilization. It is one of the excellent bamboo species for bamboo shoots in the subtropics. It is widely distributed in southern Zhejiang and Fujian, China. It has the characteristics of long shoot period and high yield. Its shoots are fresh, sweet and refreshing, crisp and tender in texture. Because its bamboo shoots are similar in shape to horseshoes, they are called horseshoe shoots. Studies have shown that green bamboo shoots have the functions of lowering cholesterol, anti-oxidation, lowering blood sugar, immunomodulation and regulating intestinal flora. At present, the research and development of green bamboo shoot protein is mainly concentrated in the field of food and medicine. In order to realize the high-value utilization of green bamboo shoots, this application uses green bamboo shoots as raw materials to extract different proteins, and applies them to fluorescence imaging, pH detection, ion detection, etc., which significantly expands the application field of green bamboo shoot protein and realizes high-value utilization. Summary of the invention

[0004] The present invention provides a use of green bamboo shoot protein. The green bamboo shoot protein comprises acid-extracted protein, salt-extracted protein, alcohol-extracted protein and alkali-extracted protein sequentially extracted from green bamboo shoots. The aforementioned proteins can be used for ion detection and fluorescence imaging, thereby significantly improving the added value of the green bamboo shoot protein.

[0005] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0006] A use of green bamboo shoot protein, the green bamboo shoot protein comprising acid-extracted protein, salt-extracted protein, alcohol-extracted protein and alkali-extracted protein sequentially extracted from green bamboo shoots; the acid-extracted protein, salt-extracted protein, alcohol-extracted protein and / or alkali-extracted protein are used for fluorescence imaging.

[0007] The fluorescence imaging concentration of the above acid-extracted protein, salt-extracted protein, alcohol-extracted protein and / or alkali-extracted protein is ≤5 μg / ml.

[0008] The alkali-extracted protein, alcohol-extracted protein, salt-extracted protein and acid-extracted protein obtained by the present invention have the function of imaging at a lower concentration. Compared with the imaging concentration of 15 mg / L, the fluorescence imaging concentration of each protein of the present invention is significantly reduced.

[0009] The acid-extracted protein, salt-extracted protein, alcohol-extracted protein and / or alkali-extracted protein have a fluorescence intensity effect on the pH of the solution and are used for pH testing of the solution in a test range of 3-10. The pH value of the solution can be determined.

[0010] The alcohol-extracted protein can also be used for fluorescence detection of calcium ions.

[0011] The alcohol-extracted protein is also used for fluorescence detection of manganese ions.

[0012] The above-mentioned alkaline-extracted protein can also be used for fluorescence detection of lead ions.

[0013] When the alkaline-extracted protein is used for the fluorescence detection of lead ions, the fluorescence intensity gradually increases with the gradual increase of the lead ion concentration; the linear relationship between the fluorescence intensity and the lead ion concentration is: y = 874.79x + 680439, R 2 =0.9731, y is the fluorescence intensity, x is the lead ion concentration, and the detection concentration range is 0~1×10 -5 mol / L.

[0014] The method for preparing the green bamboo shoot protein comprises the following steps:

[0015] (1) adding distilled water to the crushed green bamboo shoots to obtain a pulping liquid; adjusting the pH of the pulping liquid to 5.0, extracting for 0.5-1h under stirring conditions, and separating the supernatant a and the residue a by static precipitation and filtering; adding hydrochloric acid dropwise to the supernatant a until precipitation is generated, and obtaining the acid-extracted protein by static precipitation, centrifugation, and freeze-drying;

[0016] (2) adding 3% sodium chloride solution to the residue a obtained in step (1), extracting under stirring conditions for 0.5-1h, and separating the supernatant b and the residue b by static precipitation and filtration; adding hydrochloric acid dropwise to the supernatant b until precipitation is produced, and obtaining salt-extracted protein by static precipitation, centrifugation, and freeze-drying;

[0017] (3) adding 90% ethanol solution to the residue b obtained in step (2), extracting under stirring conditions for 0.5-1h, and separating the supernatant c and the residue c by static precipitation and filtration; adding hydrochloric acid dropwise to the supernatant c until precipitation is produced, and obtaining the alcohol-extracted protein by static precipitation, centrifugation, and freeze-drying;

[0018] (4) adding a NaOH alkaline solution of pH=9.0 to the residue c obtained in step (3), extracting under stirring conditions for 0.5-1h, and then separating the supernatant d and the residue d (from which dietary fiber and cellulose can be extracted) by static precipitation and filtration; adding hydrochloric acid dropwise to the supernatant d until precipitation is produced, and obtaining the alkaline-extracted protein AE-BSP by static precipitation, centrifugation, and freeze-drying.

[0019] There are great differences in the types and contents of proteins contained in different bamboo shoots. The proteins in this application are derived from green bamboo shoots.

[0020] In the above step 1), the pH of the pulping liquid needs to be adjusted to acidic, and the protein in the green bamboo shoots needs to be acid-extracted. This is substantially different from direct water extraction. The solubility of protein under different pH conditions is different, that is, the type and amount of protein extracted under different pH conditions are different; and the acidic environment will also affect the structure of the protein.

[0021] The above-mentioned 90% ethanol includes 90% ethanol and 10% water, and the above-mentioned % is volume percentage.

[0022] In order to improve the yield, in step (1), the material-liquid ratio is 1: (1-1.1). In step (2), the material-liquid ratio is 1: (9-11). In steps (3) and (4), the material-liquid ratio is 1: (6-8).

[0023] The concentration of hydrochloric acid used in the above steps is 0.5 mol / L.

[0024] In the above steps, the centrifugal speed is 8000-12000 r / min, and the centrifugal time is 8-12 min.

[0025] In this application, % refers to mass percentage unless otherwise specified.

[0026] The technologies not mentioned in the present invention are all referred to the prior art.

[0027] The green bamboo shoot protein of the present invention includes acid-extracted protein, salt-extracted protein, alcohol-extracted protein and alkali-extracted protein extracted in sequence from green bamboo shoots. The aforementioned proteins can be used for ion detection, fluorescence imaging and solution pH test, which significantly improves the added value of the green bamboo shoot protein. The fluorescence imaging concentration of the acid-extracted protein, salt-extracted protein, alcohol-extracted protein and / or alkali-extracted protein of the present invention is ≤5 μg / ml, and has the function of lower concentration imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The four proteins obtained in Example 1 are, from left to right, acid-extracted protein, salt-extracted protein, alcohol-extracted protein and alkali-extracted protein;

[0029] Figure 2 The UV absorption spectra of each protein (in the figure, WE-BSP is acid-extracted protein, SE-BSP is salt-extracted protein, EE-BSP is alcohol-extracted protein, and AE-BSP is alkali-extracted protein); the green bamboo shoot protein sample was dissolved in phosphate buffer solution (pH=7.0) with a concentration of 0.2 mg / mL;

[0030] Figure 3The fluorescence spectra of each protein (in the figure, WE-BSP is acid-extracted protein, SE-BSP is salt-extracted protein, EE-BSP is alcohol-extracted protein, AE-BSP is alkali-extracted protein, DMSO is solvent, 1 mg / ml, excitation wavelength 280 nm, Em.Slit = 5.0 nm, Ex.Slit = 5.0 nm;

[0031] Figure 4 The fluorescence spectra of acid-extracted protein at different pH values;

[0032] Figure 5 The fluorescence spectra of salt-extracted protein at different pH values;

[0033] Figure 6 The fluorescence spectra of alcohol-extracted protein at different pH values;

[0034] Figure 7 The fluorescence spectra of alkaline-extracted protein at different pH values;

[0035] Figure 8 This is the result of fluorescence enhancement selectivity experiment of alcohol-extracted protein interacting with different ions;

[0036] Fig. 9 This is the result of the fluorescence enhancement selectivity experiment of the alkaline-extracted protein interacting with different ions;

[0037] Fig.10 Alkaline extracted protein + Pb 2+ The fluorescence enhancement of Pb 2+ Linear relationship graph of concentration;

[0038] Fig.11 This is a diagram showing the results of fluorescence enhancement selectivity experiments on acid-extracted proteins interacting with different ions;

[0039] Fig.12 This is the result of fluorescence enhancement selectivity experiment of salt-extracted protein interacting with different ions;

[0040] Fig.13 This is the fluorescence imaging of acid-extracted protein;

[0041] Fig.14 This is the fluorescence imaging of salt-extracted protein;

[0042] Fig.15 This is the fluorescence imaging of alcohol-extracted protein;

[0043] Fig.16 This is the fluorescence imaging of alkali-extracted protein; DETAILED DESCRIPTION

[0044] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0045] If the temperature is not specifically stated in this application, the operation is carried out at room temperature (20-25° C.); if the stirring speed is not specifically stated, it is 150 / min; the speed of slow dripping is 45 drops / min; the solution used for pH adjustment: 0.5 mol / L hydrochloric acid or 3% sodium hydroxide solution.

[0046] Example 1

[0047] Green bamboo shoots (origin: Wenzhou, Zhejiang, harvested on July 20, 2023) were taken back, shelled, cleaned, cut into pieces, and crushed to a particle size of less than 0.5 mm. Distilled water, sodium chloride solution, ethanol solution and alkaline solution were used to grade and separate the protein of the green bamboo shoots. The specific steps are as follows:

[0048] (1) 100 g of crushed green bamboo shoots were placed in a beaker, 100 mL of distilled water was added, and the pulping liquid was pulped; the pH of the pulping liquid was adjusted to 5.0 with 0.5 mol / L hydrochloric acid, and the mixture was extracted under stirring for 1 h, and then the supernatant a and the residue a were separated by filtration; 0.5 mol / L hydrochloric acid was slowly added dropwise to the supernatant a until a precipitate was produced, and the acid-extracted protein WE-BSP was separated by standing, centrifugation (10000 r / min for 10 min), and freeze-drying, with a yield of 3.19% and a purity of 67.72%;

[0049] (2) adding 1000 mL of 3% sodium chloride solution to the residue a obtained in step (1), extracting under stirring for 1 h, and separating the supernatant b and the residue b by static precipitation and filtration; slowly adding 0.5 mol / L hydrochloric acid to the supernatant b until precipitation is produced, and separating the salt-extracted protein SE-BSP by static precipitation, centrifugation (10000 r / min centrifugation for 10 min), and freeze drying, with a yield of 4.14% and a purity of 80.25%;

[0050] (3) adding 600 mL of 90% ethanol solution to the residue b obtained in step (2), extracting under stirring for 1 h, and separating the supernatant c and the residue c by static precipitation and filtration; slowly adding 0.5 mol / L hydrochloric acid to the supernatant c until precipitation is produced, and separating the alcohol-extracted protein EE-BSP by static precipitation, centrifugation (10000 r / min for 10 min), and freeze drying, with a yield of 4.22% and a purity of 63.06%;

[0051] (4) 600 mL of NaOH alkaline solution with a pH of 9.0 was added to the residue c obtained in step (3), and after extraction for 1 h under stirring conditions, the supernatant d and the residue d were separated by static precipitation and filtration; 0.5 mol / L hydrochloric acid was slowly added dropwise to the supernatant d until precipitation was produced, and the alkali-extracted protein AE-BSP was separated by static precipitation, centrifugation (10000 r / min centrifugation for 10 min), and freeze-drying, with a yield of 5.07% and a purity of 73.06%. The acid-extracted protein WE-BSP, salt-extracted protein SE-BSP, alcohol-extracted protein EE-BSP, and alkali-extracted protein AE-BSP obtained above were respectively as follows: Figure 1 shown.

[0052] The four extracted green bamboo shoot fluorescent proteins were dissolved in phosphate buffer solution (pH = 7.0) at a concentration of 0.2 mg / mL. The ultraviolet absorption spectra were as follows: Figure 2 The results showed that each protein had two maximum absorption peaks in the range of 200-400nm, and the two peaks A were acid-extracted protein, salt-extracted protein, alcohol-extracted protein, and alkali-extracted protein from large to small.

[0053] Each protein was dissolved in DMSO, and the fluorescence spectrum characteristics were tested at a concentration of 1 mg / ml and an excitation wavelength of 280 nm (Em. Slit = 5.0 nm, Ex. Slit = 5.0 nm). The results are as follows: Figure 3 As shown, it can be seen that each protein has a strong fluorescence characteristic. Under the same concentration conditions, the fluorescence intensity (peak value: 300-400nm, 600-800nm): alkali-extracted protein > alcohol-extracted protein > salt-extracted protein > acid-extracted protein.

[0054] 0.1 ml of DMSO solution of each protein was added to a 10 ml volumetric flask, and the volume was fixed with PBS buffer to obtain four protein solutions. The corresponding protein concentration in each protein solution was 0.01 mg / ml. Under the condition of excitation wavelength of 280 nm (Em. Slit = 9.0 nm, Ex. Slit = 9.0 nm), the fluorescence spectral characteristics of each protein solution at different pH (PBS buffer) were tested. The results are as follows: Figure 4-7 As shown, it can be seen that at different pH values, acid-extracted proteins, salt-extracted proteins, alcohol-extracted proteins, and alkali-extracted proteins all have strong fluorescence characteristics. Under pH values ​​of 6-10, the fluorescence characteristics of each protein are particularly enhanced. This fingerprint can be used to determine the three buffers in which the label is lost.

[0055] like Figure 8 As shown in the figure, in PBS solution (pH = 9.18), the fluorescence intensity of the alcohol-extracted protein alone was compared with the fluorescence intensity of the alcohol-extracted protein + ions (the alcohol-extracted protein concentration was 0.01 mg / ml, and the ion concentration was 2.0×10-5 M), ion is Ni 2+ ,Ca 2+ ,Cd 2+ ,Cr 3+ ,Fe 2+ ,Fe 3+ ,Mn 2+ ,Pb 2+ ,Cu 2+ ,Zn 2+ ,Al 3+ ,Depend on Figure 8 It can be seen that alcohol-extracted protein + Ca 2+ and alcohol-extracted protein + Mn 2+ The fluorescence intensity of the system is significantly enhanced in different wavelength bands. Figure 8 Only EE-BSP in the middle is the intensity curve when only alcohol-extracted protein is added.

[0056] In PBS solution (pH = 9.18), alcohol-extracted protein + Ca 2+ Other ions were added to the system (the concentration of alcohol-extracted protein was 0.01 mg / ml, the ion concentration was 2.0×10 -5 M) to determine other ions for alcohol-extracted protein + Ca 2+ The influence of the fluorescence intensity of the system, other ions are Cd 2+ ,Co 2+ ,Cr 3+ ,Fe 2+ ,Fe 3+ ,K + ,Mn 2+ ,Na + ,Hg 2+ ,Pb 2+ ,Cu 2+ ,Zn 2+ Mg 2+ ,Al 3+ ,B 3+ and / or ClO - The results showed that other ions can enhance the protein extraction rate. 2+ The fluorescence intensity of the system was not affected (the influence degree was less than 0.001%, which was considered as no influence, and the other same expressions had the same meaning), indicating that the alcohol-extracted protein of the present invention has strong competitiveness and can be used for Ca 2+ Detection.

[0057] In PBS solution (pH = 9.18), alcohol-extracted protein + Mn 2+ Other ions were added to the system (the concentration of alcohol-extracted protein was 0.01 mg / ml, the ion concentration was 2.0×10 -5 M) to determine other ions for alcohol-extracted protein + Mn 2+ The influence of the fluorescence intensity of the system, other ions are Ca2+ ,Cd 2+ ,Co 2+ ,Cr 3+ ,Fe 2+ ,Fe 3+ ,K + ,Na + ,Hg 2+ ,Pb 2+ ,Cu 2+ ,Zn 2+ Mg 2+ ,Al 3+ ,B 3+ and / or ClO - - etc., the results showed that other ions have a significant effect on alcohol-extracted protein + Mn 2+ The fluorescence intensity of the system was not affected, indicating that the alcohol-extracted protein of the present invention has strong competitiveness and can be used for Mn 2+ Detection.

[0058] like Fig. 9 As shown in the figure, in PBS solution (pH = 9.18), the fluorescence intensity of the alkali-extracted protein alone was compared with the fluorescence intensity of the alkali-extracted protein + ions (the concentration of the alkali-extracted protein was 0.01 mg / ml, and the ion concentration was 2.0×10 -5 M), ion is Ni 2+ ,Ca 2+ ,Cd 2+ ,Cr 3+ ,Fe 2+ ,Fe 3+ ,Mn 2+ ,Pb 2+ ,Cu 2+ ,Zn 2+ ,Al 3+ ,Depend on Fig. 9 It can be seen that alkaline protein + Pb 2+ The fluorescence intensity of the system is significantly enhanced in different wavelength bands. Fig. 9 Only AE-BSP is the intensity curve when only alkali-extracted protein is added.

[0059] In PBS solution (pH = 9.18), the alkaline-extracted protein + Pb 2+ Other ions were added to the system (the concentration of alkaline extracted protein was 0.01 mg / ml, the ion concentration was 2.0×10 -5 M) to determine other ion pairs, alkali-extracted proteins + Pb 2+ The influence of the fluorescence intensity of the system, other ions are Cd 2+ ,Co 2+ ,Cr 3+ ,Fe 2+ ,Fe 3+ ,K +,Mn 2+ ,Na + ,Hg 2+ ,Pb 2+ ,Cu 2+ ,Zn 2+ Mg 2+ ,Al 3+ ,B 3+ and / or ClO - The results showed that other ions can extract protein + Pb + The fluorescence intensity of the system was not affected, indicating that the alkaline protein extraction of the present invention has strong competitiveness and can be used for Pb 2+ Detection.

[0060] like Fig.10 As shown in the figure, in a PBS solution (pH = 9.18), alkali-extracted protein (concentration of 0.01 mg / ml) was added. As the lead ion concentration gradually increased, the fluorescence intensity gradually increased. The linear relationship between the fluorescence intensity and the lead ion concentration is: y = 874.79x + 680439, R 2 =0.9731, y is the fluorescence intensity, x is the lead ion concentration, and the detection concentration range is 0~1×10 -5 mol / L.

[0061] like Fig.11 As shown, in PBS solution (pH = 9.18), the fluorescence intensity of only acid-extracted protein was compared with the fluorescence intensity of acid-extracted protein + ions (the concentration of acid-extracted protein was 0.01 mg / ml, and the concentration of ions was 2.0×10 -5 M), ion is Ni 2+ ,Ca 2+ ,Cd 2+ ,Cr 3+ ,Fe 2+ ,Fe 3+ ,Mn 2+ ,Pb 2+ ,Cu 2+ ,Zn 2+ ,Al 3+ ,Depend on Fig.11 It can be seen that the fluorescence intensity of the acid-extracted protein + various ion systems did not increase significantly. Fig.11 Only WE-BSP in the figure is the strength curve when only acid-extracted protein is added. Fig.12 It can be seen that the fluorescence intensity of the salt-extracted protein + various ion systems has not been significantly enhanced.

[0062] like Fig.12As shown, in PBS solution (pH = 9.18), the fluorescence intensity of only salt-extracted protein was compared with the fluorescence intensity of salt-extracted protein + ions (salt-extracted protein concentration was 0.01 mg / ml, ion concentration was 2.0×10 -5 M), ion is Ni 2+ ,Ca 2+ ,Cd 2+ ,Cr 3+ ,Fe 2+ ,Fe 3+ ,Mn 2+ ,Pb 2+ ,Cu 2+ ,Zn 2+ ,Al 3+ ,Depend on Fig.12 It can be seen that the fluorescence intensity of the salt-extracted protein + various ion systems did not increase significantly. Fig.12 Only SE-BSP is the intensity curve when only salt-extracted protein is added.

[0063] Cell fluorescence imaging:

[0064] Hela cells in the logarithmic growth phase were collected by digestion with 0.2% trypsin and 0.15% EDTA, and then the cells were diluted to 4 × 10 4 / ml, take 1ml and add it to a 24-well cell culture plate. After culturing for 24 hours at 37°C and 5% CO2, wash it twice with PBS (phosphate buffer solution). Then, culture Hela cells with 5μg / ml of acid-extracted protein, salt-extracted protein, alcohol-extracted protein and alkali-extracted protein for 1h (37°C, 5% CO2), and wash it twice with PBS (phosphate buffer solution). Finally, observe the fluorescence imaging photos under a confocal fluorescence microscope to obtain a clear Hela cell fluorescence imaging effect diagram.

[0065] The fluorescence imaging results of acid-extracted protein, salt-extracted protein, alcohol-extracted protein and alkali-extracted protein are shown in Figure 2. Figure 13-16 As shown, from Figure 13-16 It can be seen that alkali-extracted protein, alcohol-extracted protein, salt-extracted protein and acid-extracted protein can all be used for fluorescence imaging at a concentration as low as 5 μg / ml, while the existing invention patent (a method for separating a fluorescent composition from bamboo shoots and the use of the obtained fluorescent composition) requires a concentration of 15 mg / L (5 μg / ml). The alkali-extracted protein, alcohol-extracted protein, salt-extracted protein and acid-extracted protein obtained by the present invention have the function of imaging at a lower concentration.

Claims

1. A use of green bamboo shoot protein, characterized in that: Green bamboo shoot proteins include acid-extracted proteins, salt-extracted proteins, alcohol-extracted proteins and alkali-extracted proteins extracted sequentially from green bamboo shoots; the acid-extracted proteins, salt-extracted proteins, alcohol-extracted proteins and / or alkali-extracted proteins are used for fluorescence imaging.

2. The use of green bamboo shoot protein according to claim 1, characterized in that: The fluorescence imaging concentration of the acid-extracted protein, salt-extracted protein, alcohol-extracted protein and / or alkali-extracted protein is ≤5 μg / ml.

3. The use of green bamboo shoot protein according to claim 1, characterized in that: Acid-extracted protein, salt-extracted protein, alcohol-extracted protein and / or alkali-extracted protein have a fluorescence intensity effect on the pH of the solution and are used for pH testing of the solution in a test range of 3-10.

4. The use of green bamboo shoot protein according to claim 1, characterized in that: The alcohol-extracted protein was used for fluorescence detection of calcium ions.

5. The use of green bamboo shoot protein according to claim 1, characterized in that: The alcohol-extracted protein was used for fluorescence detection of manganese ions.

6. The use of green bamboo shoot protein according to claim 1, characterized in that: Alkaline-extracted protein was used for fluorescence detection of lead ions.

7. The use of green bamboo shoot protein according to claim 6, characterized in that: As the lead ion concentration gradually increases, the fluorescence intensity gradually increases; the linear relationship between the fluorescence intensity and the lead ion concentration is: y = 874.79x + 680439, R 2 =0.9731, y is the fluorescence intensity, x is the lead ion concentration, and the detection concentration range is 0~1×10 -5 mol / L.

8. The use of green bamboo shoot protein according to any one of claims 1 to 7, characterized in that: The preparation method of green bamboo shoot protein comprises the following steps: (1) adding distilled water to the crushed green bamboo shoots to obtain a pulping liquid; adjusting the pH of the pulping liquid to 5.0, extracting for 0.5-1h under stirring conditions, and separating the supernatant a and the residue a by static precipitation and filtering; adding hydrochloric acid dropwise to the supernatant a until precipitation is generated, and obtaining the acid-extracted protein by static precipitation, centrifugation, and freeze-drying; (2) adding 3% sodium chloride solution to the residue a obtained in step (1), extracting under stirring conditions for 0.5-1h, and separating the supernatant b and the residue b by static precipitation and filtration; adding hydrochloric acid dropwise to the supernatant b until precipitation is produced, and obtaining salt-extracted protein by static precipitation, centrifugation, and freeze-drying; (3) adding 90% ethanol solution to the residue b obtained in step (2), extracting under stirring conditions for 0.5-1h, and separating the supernatant c and the residue c by static precipitation and filtration; adding hydrochloric acid dropwise to the supernatant c until precipitation is produced, and obtaining the alcohol-extracted protein by static precipitation, centrifugation, and freeze-drying; (4) adding a NaOH alkaline solution of pH=9.0 to the residue c obtained in step (3), extracting under stirring conditions for 0.5-1h, and then separating the supernatant d and the residue d by static precipitation and filtration; adding hydrochloric acid dropwise to the supernatant d until precipitation is produced, and obtaining the alkaline-extracted protein by static precipitation, centrifugation, and freeze-drying.

9. The use of green bamboo shoot protein according to claim 8, characterized in that: In step (1), the material-liquid ratio is 1:(1-1.1); in step (2), the material-liquid ratio is 1:(9-11); in steps (3) and (4), the material-liquid ratio is both 1:(6-8).

10. The use of green bamboo shoot protein according to claim 7, characterized in that: The concentration of hydrochloric acid used in each step is 0.5 mol / L; the centrifugal speed in each step is 8000-12000 r / min, and the centrifugal time is 8-12 min.

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