CN116998582A - Preparation method of high-solubility oil plant protein - Google Patents

Abstract

The invention discloses a preparation method of high-solubility oil plant protein. The method comprises the steps of dispersing oil plant protein in water, adjusting pH to 10.0-10.5 to obtain alkaline protein solution, carrying out ultrasonic treatment, adjusting pH to 7.0-7.5, carrying out high-pressure homogenization, finally freeze-drying, and sieving to obtain the high-solubility oil plant protein. According to the invention, an enzyme preparation is not introduced, pH change is coupled by physical modification, so that the solubility of the oil plant protein with low solubility under a neutral condition is effectively improved, and the application of the oil plant protein in the food field is widened.

Description

A kind of preparation method of high-solubility oil plant protein

Technical field

The invention belongs to the technical field of oil plant protein processing and relates to a method for preparing high-solubility oil plant protein.

Background technique

Oil plants refer to plants whose seeds or fruits are rich in vegetable oil. They are widely grown to extract edible vegetable oil or vegetable oil for industrial purposes. Common oil plants include peanuts, walnuts, sesame seeds, sunflower seeds, etc.

The pressing method is a common method for extracting vegetable oil from oil plants. This method usually involves physically pressing the seeds, fruits or flowering parts of oil plants to obtain vegetable oil and remaining plant solids. It has a wide range of applications. It is easy to operate and is one of the main oil production methods.

Most oil plant proteins are extracted from defatted cakes. Their low solubility under neutral conditions is a common problem, which greatly limits their application prospects in food and other fields. Most oil plant proteins are rich in gluten. Gluten contains a large number of hydrophobic amino acids and has a tight and aggregated spatial structure. These characteristics lead to low solubility of oil plant proteins. Therefore, in order to improve the application prospects of oil plant proteins, it is necessary to Make modifications.

Protein modification methods mainly include physical modification, chemical modification and enzymatic modification. Among them, physical modification does not cause environmental pollution and is favored because it meets the requirements of green processing. Ultrasound and high-pressure homogenization have been proven to effectively improve the tight structure of proteins. In addition, alkaline cycling, as a simple and safe chemical modification method, uses the structural expansion of proteins under alkaline conditions to improve their solubility and has been widely used in the production of plant proteins. Enzymatic modification is the most common method to improve the functional properties of proteins. Restricted proteases destroy the protein peptide chain structure by hydrolyzing specific amino acid residue sites, thereby improving its spatial structure and surface properties to improve its solubility. However, enzymatic modification often results in undesirable enzymatic flavors and the production of bitter peptides, and proteases may become potential allergens. In addition, plant proteins have a tight structure and have fewer exposed enzymatic hydrolysis sites, which leads to shortcomings such as low enzymatic hydrolysis rate and poor enzymatic hydrolysis effect (Guigoz Y, SolmsJ. Bitter peptides, occurrence and structure [J]. Chemical Senses, 1976, 2(1):71-84.).

Contents of the invention

The object of the present invention is to provide a method for preparing high-solubility oil plant protein, which uses high-pressure homogeneous coupling ultrasonic-alkaline cycle to process oil plant protein to obtain high-solubility oil plant protein.

The technical solutions to achieve the purpose of the present invention are as follows:

A method for preparing high-solubility oil plant protein, including the following steps:

(1) Disperse oil plant protein in water and stir until fully hydrated to obtain a uniform protein dispersion;

(2) Use sodium hydroxide solution to adjust the pH of the protein dispersion to 10.0-10.5 to obtain an alkaline protein dispersion;

(3) Ultrasonic treatment of the alkaline protein dispersion to obtain an ultrasonic treated alkaline protein dispersion;

(4) Use hydrochloric acid solution to adjust the pH of the ultrasonic alkaline protein dispersion to 7.0-7.5 to obtain an ultrasonic-alkaline circulating protein dispersion;

(5) Perform high-pressure homogenization of the ultrasonic-alkaline circulating protein dispersion and cycle three times to obtain a high-pressure homogeneous coupled ultrasonic-alkaline circulating protein dispersion;

(6) The high-pressure homogeneous coupling ultrasonic-alkaline circulating protein dispersion is freeze-dried, crushed and sieved to obtain high-solubility plant protein.

In step (1), the oil plant protein of the present invention is a common oil plant protein, such as peanut protein, walnut protein, sesame protein, sunflower seed protein, etc.

Preferably, in step (1), the concentration of the protein dispersion is 5 mg/ml.

Preferably, in step (1), the stirring time is 2-3h.

Preferably, in step (2), the concentration of the sodium hydroxide solution is 1M.

Preferably, in step (3), the ultrasonic power is 400-500W, the ultrasonic working time is 10s, the ultrasonic interval time is 15s, the ultrasonic temperature is 16°C, and the total ultrasonic time is 2h.

Preferably, in step (4), the concentration of the hydrochloric acid solution is 1M.

Preferably, in step (5), the homogenization pressure is 50-100Mpa, the homogenization temperature is 15°C, and the frequency is 40Hz.

Preferably, in step (4), the freeze-drying temperature is -80°C, and the screen mesh size is 100 mesh.

In the present invention, the oil plant protein is first placed under alkaline conditions to loosen its structure, and then the explosive force and heat generated by ultrasonic cavitation are used to rearrange the protein spatial structure. In the cycle of neutral-alkaline-neutral, the protein structure goes from polymerization to depolymerization to repolymerization. This process will lead to changes in the primary, secondary, and tertiary structures of the protein. After ultrasonic alkaline cycle treatment, the protein solution passes through the restricted pores in the high-pressure homogenizer under pressure, and the protein structure is further destroyed, showing higher surface hydrophobicity. In addition, protein aggregates are destroyed to form smaller particle sizes. new aggregates, which will facilitate their dissolution in water.

Compared with the prior art, the present invention has the following advantages:

(1) The present invention modifies oil plant protein through physical and chemical methods without using enzyme preparations, and has the advantages of simple operation, safety, high speed and no environmental pollution.

(2) The present invention uses oil plant protein as raw material, and uses high-pressure homogeneous coupling ultrasonic-alkaline circulation treatment to make the solubility of walnut protein, peanut protein, sesame protein and sunflower seed protein under the condition of pH=7.0 from 20.68±0.24% respectively. , 18.47±0.34%, 14.93±0.88% and 33.26±0.41% increased to 39.49±0.48%, 37.40±0.80%, 34.16±1.06% and 60.99±1.14%, broadening the application scope of oil plant protein resources with low solubility And make the product protein have higher added value.

Description of the drawings

Figure 1 shows the solubility of walnut protein obtained under different treatment methods in water with pH=7.0.

Figure 2 shows the solubility of peanut protein in pH=7.0 water obtained under different treatment methods.

Figure 3 shows the solubility of sesame protein in pH=7.0 water obtained under different treatment methods.

Figure 4 shows the solubility of sunflower seed protein obtained under different treatment methods in water with pH=7.0.

Detailed ways

The present invention will be further described in detail below with reference to specific embodiments and drawings.

1. The oil plant proteins (walnut protein, peanut protein, sesame protein and sunflower seed protein) used in the following examples are prepared using existing methods, specifically as follows:

(1) Crush walnut defatted meal, peanut defatted meal, sesame defatted meal and sunflower seed defatted meal respectively through a 100 mesh sieve to produce walnut powder, peanut powder, sesame powder and sunflower seed powder;

(2) According to the material-to-liquid ratio of 1:30, disperse walnut powder, peanut powder, sesame powder and sunflower seed powder in water respectively to obtain walnut powder suspension, peanut powder suspension, sesame powder suspension and sunflower seed powder suspension. ;

(3) Use 1M sodium hydroxide solution to adjust the pH of walnut powder suspension, peanut powder suspension, sesame powder suspension and sunflower seed powder suspension to 11.0 respectively, stir in a water bath at 40°C for 2 hours and then centrifuge at 4000r/min for 30min , discard the precipitate to obtain walnut protein extract, peanut protein extract, sesame protein extract and sunflower seed protein extract;

(4) Use 1M hydrochloric acid solution to adjust the pH of walnut protein extract, peanut protein extract, sesame protein extract and sunflower seed protein extract to 4.5 respectively, centrifuge at 4000r/min for 30 minutes, and collect the precipitate to form walnut protein and peanut protein. , sesame protein and sunflower seed protein;

(5) Reconstitute walnut protein, peanut protein, sesame protein and sunflower seed protein with water, dialyze in a 500Da dialysis bag for 48 hours, and freeze-dry for storage.

The protein content was measured according to the Kjeldahl nitrogen determination method in GB5009.5-2016. The conversion coefficient for walnut protein is 5.30, the conversion coefficient for peanut protein is 5.46, the conversion coefficient for sesame protein is 5.30, and the conversion coefficient for sunflower seed protein is 5.30. The purity of walnut protein, peanut protein, sesame protein and sunflower seed protein extracted by the above method were 83.43±1.53%, 81.49±2.77%, 84.17±1.88% and 81.91±1.06% respectively. Using the above method, the extraction rates of walnut protein, peanut protein, sesame protein and sunflower seed protein were 74.33%±0.97%, 84.54±2.74%, 79.38±1.30% and 77.86±2.43% respectively.

2. In the following examples, the method for measuring protein solubility is as follows:

The protein was suspended in water with pH = 7.0, stirred at room temperature for 2 hours to fully hydrate, and then centrifuged at 10,000 r/min for 10 minutes. The supernatant was diluted and the protein concentration in the supernatant was measured using the BCA method. The formula for calculating protein solubility (S) is:

Among them: C is the protein concentration of the supernatant, N is the dilution factor, V is the volume of the solution, and M is the weighed protein mass.

3. Data processing: The experiments were repeated three times. Origin was used to analyze and draw the data. The results were expressed as "mean ± standard deviation". SPSS software was used to analyze the data for significance (P<0.05 indicates a significant difference). .

Example 1

1. Preparation of walnut protein through alkaline cycle:

(1) Disperse walnut protein in water, stir and fully hydrate for 2 hours to obtain a uniform walnut protein dispersion with a concentration of 5 mg/ml;

(2) Use 1M sodium hydroxide solution to adjust the pH of the walnut protein dispersion to 10.0-10.5 to obtain an alkaline walnut protein dispersion;

(3) Use 1M hydrochloric acid solution to adjust the pH of the alkaline walnut protein dispersion to 7.0-7.5 to obtain an alkaline circulating walnut protein dispersion;

(4) The alkaline circulating walnut protein dispersion is freeze-dried and crushed through a 100-mesh sieve to obtain walnut protein.

2. Preparation of walnut protein by ultrasonic treatment:

(1) Disperse walnut protein in water, stir and fully hydrate for 2 hours to obtain a uniform walnut protein dispersion with a concentration of 5 mg/ml;

(2) Use contact ultrasonic equipment to process the walnut protein dispersion for 2 hours to obtain the ultrasonic treated walnut protein dispersion. The ultrasonic conditions are: power 500W, working for 10s, interval of 15s, and temperature of 16°C;

(3) The ultrasonic-treated walnut protein dispersion is freeze-dried and crushed through a 100-mesh sieve to obtain walnut protein.

3. Preparation of walnut protein by high-pressure homogenization treatment:

(1) Disperse walnut protein in water, stir and fully hydrate for 2 hours to obtain a uniform walnut protein dispersion with a concentration of 5 mg/ml;

(2) Circulate the walnut protein dispersion three times in a high-pressure homogenizer to obtain a high-pressure homogenized walnut protein dispersion. The homogenization conditions are: homogenization pressure is 50Mpa, homogenization temperature is 15°C, and frequency is 40Hz;

(3) The high-pressure homogeneous walnut protein dispersion is freeze-dried and crushed through a 100-mesh sieve to obtain walnut protein.

4. Preparation of walnut protein by ultrasonic-alkaline cycle:

(1) Disperse walnut protein in water, stir and fully hydrate for 2 hours to obtain a uniform walnut protein dispersion with a concentration of 5 mg/ml;

(2) Use 1M sodium hydroxide solution to adjust the pH of the walnut protein dispersion to 10.0-10.5 to obtain an alkaline walnut protein dispersion;

(3) Use contact ultrasonic equipment to treat the alkaline walnut protein dispersion for 2 hours to obtain the ultrasonic treated alkaline walnut protein dispersion. The ultrasonic conditions are: power 500W, working for 10s, interval of 15s, and temperature of 16°C.

(4) Use 1M hydrochloric acid solution to adjust the pH of the ultrasonic alkaline walnut protein dispersion to 7.0-7.5 to obtain an ultrasonic-alkaline circulating walnut protein dispersion;

(5) The ultrasonic-alkaline circulating walnut protein dispersion is freeze-dried and pulverized through a 100-mesh sieve to obtain walnut protein.

5. Preparation of walnut protein by high-pressure homogenization-alkaline cycle:

(1) Disperse walnut protein in water, stir and fully hydrate for 2 hours to obtain a uniform walnut protein dispersion with a concentration of 5 mg/ml;

(2) Use 1M sodium hydroxide solution to adjust the pH of the walnut protein dispersion to 10.0-10.5 to obtain an alkaline walnut protein dispersion;

(3) Circulate the alkaline walnut protein dispersion three times in a high-pressure homogenizer to obtain a high-pressure homogenized alkaline walnut protein dispersion. The homogenization conditions are: homogenization pressure is 50Mpa, homogenization temperature is 15°C, frequency is 40Hz.

(4) Use 1M hydrochloric acid solution to adjust the pH of the high-pressure homogenized alkaline walnut protein dispersion to 7.0-7.5 to obtain a high-pressure homogenized-alkaline circulating walnut protein dispersion;

(5) The high-pressure homogenized-alkaline circulating walnut protein dispersion is freeze-dried and crushed through a 100-mesh sieve to obtain walnut protein.

6. Preparation of high-solubility walnut protein using high-pressure homogeneous coupling ultrasonic-alkaline cycle:

(1) Disperse walnut protein in water, stir and fully hydrate for 2 hours to obtain a uniform walnut protein dispersion with a concentration of 5 mg/ml;

(2) Use 1M sodium hydroxide solution to adjust the pH of the walnut protein dispersion to 10.0-10.5 to obtain an alkaline walnut protein dispersion;

(3) Use contact ultrasonic equipment to treat the alkaline walnut protein dispersion for 2 hours to obtain the ultrasonic treated alkaline walnut protein dispersion. The ultrasonic conditions are: power 500W, working for 10s, interval of 15s, and temperature of 16°C.

(4) Use 1M hydrochloric acid solution to adjust the pH of the ultrasonic alkaline walnut protein dispersion to 7.0-7.5 to obtain an ultrasonic-alkaline circulating walnut protein dispersion;

(5) The ultrasonic-alkaline circulating walnut protein dispersion is circulated three times in a high-pressure homogenizer to obtain a high-pressure homogeneous coupled ultrasonic-alkaline circulating walnut protein dispersion. The homogenization conditions are: the homogenization pressure is 50Mpa, and the homogeneous The mass temperature is 15℃ and the frequency is 40Hz.

(6) The high-pressure homogeneous coupled ultrasonic-alkaline circulating walnut protein dispersion is freeze-dried and crushed through a 100-mesh sieve to obtain high-solubility walnut protein.

Figure 1 shows the solubility of walnut protein in pH=7.0 water obtained under different treatment methods: alkaline cycle, ultrasonic treatment, high-pressure homogenization treatment, ultrasonic-alkaline cycle, high-pressure homogenization-alkaline cycle and high-pressure homogenization coupled ultrasound -Alkaline circulation treatment increased the solubility of walnut protein by 12.67%, 42.46%, 28.96%, 55.20%, 38.91% and 90.96% respectively. It can be seen that high-pressure homogeneous coupled ultrasound-alkaline circulation treatment has a significant effect on improving the solubility of walnut protein.

Example 2

1. Preparation of peanut protein by alkaline cycle: basically the same as Example 1, except that walnut protein is replaced by peanut protein.

2. Preparation of peanut protein by ultrasonic treatment: basically the same as in Example 1, except that walnut protein is replaced by peanut protein.

3. Preparation of peanut protein by high-pressure homogenization treatment: basically the same as in Example 1, except that walnut protein is replaced by peanut protein.

4. Preparation of peanut protein by ultrasonic-alkaline cycle: basically the same as in Example 1, except that walnut protein is replaced by peanut protein.

5. Preparation of peanut protein by high-pressure homogenization-alkaline cycle: basically the same as in Example 1, except that walnut protein is replaced by peanut protein.

6. Preparation of high-solubility peanut protein by high-pressure homogeneous coupling ultrasonic-alkaline cycle: basically the same as Example 1, except that walnut protein is replaced by peanut protein.

Figure 2 shows the solubility of peanut protein in pH=7.0 water obtained under different treatment methods, alkaline cycle, ultrasonic treatment, high-pressure homogenization treatment, ultrasonic-alkaline cycle, high-pressure homogenization-alkaline cycle and high-pressure homogenization coupling Ultrasonic-alkaline cycle treatment increased the solubility of peanut protein by 34.51%, 49.89%, 48.12%, 81.63%, 58.45% and 102.55% respectively. It can be seen that high-pressure homogeneous coupling ultrasonic-alkaline cycle treatment has a significant effect on improving the solubility of peanut protein. .

Example 3

1. Preparation of sesame protein by alkaline cycle: basically the same as in Example 1, except that walnut protein is replaced by sesame protein.

2. Preparation of sesame protein by ultrasonic treatment: basically the same as in Example 1, except that walnut protein is replaced by sesame protein.

3. Preparation of sesame protein by high-pressure homogenization treatment: basically the same as in Example 1, except that walnut protein is replaced by sesame protein.

4. Preparation of sesame protein by ultrasonic-alkaline cycle: basically the same as in Example 1, except that walnut protein is replaced by sesame protein.

5. Preparation of sesame protein through high-pressure homogenization-alkaline cycle: basically the same as in Example 1, except that walnut protein is replaced by sesame protein.

6. Preparation of high-solubility sesame protein by high-pressure homogeneous coupling ultrasonic-alkaline cycle: basically the same as in Example 1, except that walnut protein is replaced by sesame protein.

Figure 3 shows the solubility of sesame protein in pH=7.0 water obtained under different treatment methods, alkaline cycle, ultrasonic treatment, high-pressure homogenization treatment, ultrasonic-alkaline cycle, high-pressure homogenization-alkaline cycle and high-pressure homogenization coupling Ultrasound-alkaline cycle treatment increased the solubility of sesame protein by 57.37%, 69.59%, 60.19%, 87.15%, 81.19% and 128.84% respectively. It can be seen that high-pressure homogeneous coupled ultrasound-alkaline cycle treatment has a significant effect on improving the solubility of sesame protein. .

Example 4

1. Preparation of sunflower seed protein by alkaline cycle: basically the same as in Example 1, except that walnut protein is replaced by sunflower seed protein.

2. Preparation of sunflower seed protein by ultrasonic treatment: basically the same as in Example 1, except that walnut protein is replaced by sunflower seed protein.

3. Preparation of sunflower seed protein by high-pressure homogenization treatment: basically the same as in Example 1, except that walnut protein is replaced by sunflower seed protein.

4. Preparation of sunflower seed protein by ultrasonic-alkaline cycle: basically the same as in Example 1, except that walnut protein is replaced by sunflower seed protein.

5. Preparation of sunflower seed protein through high-pressure homogenization-alkaline cycle: basically the same as in Example 1, except that walnut protein is replaced by sunflower seed protein.

6. Preparation of high-solubility sunflower seed protein by high-pressure homogeneous coupling ultrasonic-alkaline cycle: basically the same as in Example 1, except that walnut protein is replaced by sunflower seed protein.

Figure 4 shows the solubility of sunflower seed protein in pH=7.0 water obtained under different treatment methods: alkaline cycle, ultrasonic treatment, high-pressure homogenization treatment, ultrasonic-alkaline cycle, high-pressure homogenization-alkaline cycle and high-pressure homogenization Coupled ultrasound-alkaline cycle treatment increased the solubility of sunflower seed protein by 9.51%, 34.83%, 21.12%, 49.24%, 37.35% and 83.37% respectively. It can be seen that high-pressure homogeneous coupled ultrasound-alkaline cycle treatment can improve the solubility of sunflower seed protein. With significant effect.

Comparative example 1

(1) Disperse walnut protein in water, stir and fully hydrate for 2 hours to obtain a uniform walnut protein dispersion with a concentration of 5 mg/ml;

(2) Circulate the walnut protein dispersion three times in a high-pressure homogenizer to obtain a high-pressure homogenized walnut protein dispersion. The homogenization conditions are: the homogenization pressure is 50Mpa, the homogenization temperature is 15°C, and the frequency is 40Hz;

(3) Use 1M sodium hydroxide solution to adjust the pH of the high-pressure homogeneous walnut protein dispersion to 10.0-10.5 to obtain an alkaline high-pressure homogeneous walnut protein dispersion;

(4) Use contact ultrasonic equipment to process the alkaline high-pressure homogeneous walnut protein dispersion for 2 hours to obtain the ultrasonic-treated alkaline high-pressure homogeneous walnut protein dispersion. The ultrasonic conditions are: power 500W, working for 10s, interval of 15s, and temperature of 16°C. .

(5) Use 1M hydrochloric acid solution to adjust the pH of the ultrasonic alkaline high-pressure homogeneous walnut protein dispersion to 7.0-7.5 to obtain a high-pressure homogeneous coupled ultrasonic-alkaline circulating walnut protein dispersion;

(6) The high-pressure homogeneous coupled ultrasonic-alkaline circulating walnut protein dispersion is freeze-dried and crushed through a 100-mesh sieve to obtain high-solubility walnut protein.

In this comparative example, walnut protein is first subjected to high-pressure homogenization treatment, and then ultrasonic-alkaline cycle treatment is performed. This treatment method increases the solubility of walnut protein by 73.30%, which is significantly lower than that in Example 2. Ultrasonic-alkaline cycle treatment is performed first. High-pressure homogenized walnut protein (90.96%).

Claims (9)

1. A method for preparing high-solubility oil plant protein, which is characterized by comprising the following steps: (1) Disperse oil plant protein in water and stir until fully hydrated to obtain a uniform protein dispersion; (2) Use sodium hydroxide solution to adjust the pH of the protein dispersion to 10.0-10.5 to obtain an alkaline protein dispersion; (3) Ultrasonic treatment of the alkaline protein dispersion to obtain an ultrasonic treated alkaline protein dispersion; (4) Use hydrochloric acid solution to adjust the pH of the ultrasonic alkaline protein dispersion to 7.0-7.5 to obtain an ultrasonic-alkaline circulating protein dispersion; (5) Perform high-pressure homogenization of the ultrasonic-alkaline circulating protein dispersion and cycle three times to obtain a high-pressure homogeneous coupled ultrasonic-alkaline circulating protein dispersion; (6) Freeze-dry the high-pressure homogeneous coupled ultrasonic-alkaline circulating protein dispersion, crush and sieve to obtain high-solubility plant protein. 2. The preparation method according to claim 1, characterized in that in step (1), the oil plant protein is peanut protein, walnut protein, sesame protein or sunflower seed protein. 3. The preparation method according to claim 1, characterized in that in step (1), the concentration of the protein dispersion is 5 mg/ml. 4. The preparation method according to claim 1, characterized in that, in step (1), the stirring time is 2-3 h. 5. The preparation method according to claim 1, characterized in that in step (2), the concentration of the sodium hydroxide solution is 1M. 6. The preparation method according to claim 1, characterized in that in step (3), the ultrasonic power is 400-500 W, the ultrasonic working time is 10 s, the ultrasonic interval time is 15 s, and the ultrasonic temperature is 16°C. The total ultrasound time is 2h. 7. The preparation method according to claim 1, characterized in that in step (4), the concentration of the hydrochloric acid solution is 1M. 8. The preparation method according to claim 1, characterized in that in step (5), the homogenization pressure is 50-100 MPa, the homogenization temperature is 15°C, and the frequency is 40 Hz. 9. The preparation method according to claim 1, characterized in that, in step (4), the freeze-drying temperature is -80°C, and the mesh size of the screen is 100 mesh.