Microparticulated soy protein and methods of making and using the same

Abstract

This invention discloses a micronized soybean protein, its preparation method, and its applications. The preparation method of the micronized soybean protein of this invention includes the following steps: 1) preparing a soybean meal dispersion with a pH of 7.0–9.0; 2) separating the soybean protein clear liquid from the soybean meal dispersion by centrifugation; 3) enzymatically converting the soybean protein clear liquid into a micronized soybean protein dispersion; 4) centrifuging the micronized soybean protein dispersion, collecting the solids, and obtaining micronized soybean protein curd; 5) dispersing the micronized soybean protein curd with water, adjusting the pH to 5.0–7.0, and then spray-drying. The micronized soybean protein of this invention has the characteristics of high protein content within the particles, concentrated particle size distribution, and stable properties in different pH environments. Furthermore, the high-concentration micronized soybean protein solution prepared from it has advantages such as excellent dispersibility, low viscosity, and weak gelation under heat-induced conditions, making it suitable for large-scale industrial applications.

Description

Technical Field

[0001] This invention relates to the field of soybean protein deep processing technology, specifically to a micronized soybean protein, its preparation method, and its application. Background Technology

[0002] Soybeans are one of the world's most widely cultivated crops, and soy protein extracted from soybeans is rich in various essential amino acids, possessing high nutritional value and functional properties. The functional properties of soy protein mainly include solubility, dispersibility, emulsification, foaming, and gelling properties, and it is widely used in the food industry to improve the texture and sensory characteristics of food. However, soy protein isolate obtained through traditional methods suffers from excessively high viscosity at high concentrations in liquid plant protein food systems, and it is prone to aggregation or gelation after heat treatment, negatively impacting the texture and sensory characteristics of the food.

[0003] Therefore, developing a soybean protein with good thermal stability that can maintain low viscosity at high concentrations is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a micronized soybean protein, its preparation method, and its application.

[0005] The technical solution adopted in this invention is:

[0006] A method for preparing micronized soybean protein includes the following steps:

[0007] 1) Disperse defatted soybean meal in water, then adjust the pH to 7.0–9.0 to obtain a soybean meal dispersion;

[0008] 2) Centrifuge the soybean meal dispersion, take the clear liquid and adjust the pH value to 4.5-7.0 to obtain soybean protein clear liquid;

[0009] 3) Add the protease to the soybean protein clear liquid for enzymatic hydrolysis and enzyme inactivation to obtain a micronized soybean protein dispersion;

[0010] 4) Centrifuge the micronized soybean protein dispersion, collect the solids, and obtain micronized soybean protein curd;

[0011] 5) Disperse the micronized soy protein curd with water, adjust the pH to 5.0-7.0, and then spray dry to obtain micronized soy protein.

[0012] Preferably, the mass ratio of defatted soybean meal to water in step 1) is 1:5 to 20.

[0013] Preferably, the dispersion method in step 1) is mechanical stirring, with the stirring speed of the stirrer being 200 rpm to 1000 rpm and the stirring time being 1 h to 3 h.

[0014] Preferably, in step 1), the pH value is adjusted by using a sodium hydroxide solution with a concentration of 1 mol / L to 3 mol / L.

[0015] Preferably, the centrifugation in step 2) is carried out at a centrifuge speed of 5000 rpm to 10000 rpm for a centrifugation time of 5 min to 15 min.

[0016] Preferably, in step 2), the pH value is adjusted by using a hydrochloric acid solution with a concentration of 1 mol / L to 3 mol / L.

[0017] Preferably, the protease in step 3) is at least one of papain, bromelain, and ginger protease.

[0018] Preferably, the amount of protease used in step 3) is 0.02% to 0.1% of the solid content of the soybean protein solution.

[0019] Preferably, the enzymatic hydrolysis in step 3) is carried out at a temperature of 60℃ to 85℃ for a time of 10 min to 60 min.

[0020] Preferably, the enzyme inactivation method in step 3) is high-temperature enzyme inactivation.

[0021] Preferably, the high-temperature enzyme inactivation is carried out in a water bath at a temperature of 95℃ to 105℃ for a time of 5 min to 20 min.

[0022] Preferably, the centrifugation in step 4) is carried out at a centrifuge speed of 5000 rpm to 10000 rpm for a centrifugation time of 5 min to 15 min.

[0023] Preferably, the mass ratio of micronized soybean protein curd to water in step 5) is 1:2 to 10.

[0024] Preferably, in step 5), the pH value is adjusted by using a sodium hydroxide solution with a concentration of 1 mol / L to 3 mol / L.

[0025] Preferably, the operating parameters for spray drying in step 5) are: inlet air temperature of 160℃~200℃, outlet air temperature of 90℃~110℃, and injection rate of 1.5mL / min~4.5mL / min.

[0026] A micronized soybean protein, prepared by the above-described method.

[0027] Preferably, the particle size of the micronized soybean protein is 1 μm to 15 μm.

[0028] Preferably, the micronized soybean protein has a protein content greater than 850 mg / g, and the protein content inside the particles is not less than 45%.

[0029] A food product containing the aforementioned micronized soy protein.

[0030] The beneficial effects of this invention are: the micronized soybean protein of this invention has the characteristics of high protein content inside the particles, concentrated particle size distribution, and stable properties in different pH environments. Furthermore, the high-concentration micronized soybean protein solution made from it has the advantages of excellent dispersibility, low viscosity, and weak gelation under heat-induced conditions, making it suitable for large-scale industrial applications.

[0031] Specifically:

[0032] 1) The micronized soybean protein of the present invention has the characteristics of high protein content inside the particles, concentrated particle size distribution, and stable properties in different pH environments. The high-concentration micronized soybean protein solution made from it has the advantages of excellent dispersibility, low viscosity, and low gelation under heat-induced conditions, making it suitable for use in high-protein liquid foods.

[0033] 2) This invention uses a simple heat treatment method to effectively passivate the active groups on the surface of protein microparticles, and obtains soybean protein microparticles with uniform particle size distribution without homogenization treatment.

[0034] 3) This invention uses an enzymatic method to moderately hydrolyze and improve the extraction process of soybean protein to prepare micronized soybean protein curd, and then obtains micronized soybean protein by spray drying. The entire preparation process only involves simple hydrothermal treatment and modification with biological enzymes. It is simple to operate, has low energy consumption, and is suitable for large-scale industrial production. Attached Figure Description

[0035] Figure 1 This is a SEM image of the micronized soybean protein in Example 1.

[0036] Figure 2 SDS-PAGE images of micronized soybean protein in Examples 1, 3, and the comparative examples.

[0037] Figure 3 Viscosity curves of micronized soybean protein dispersions prepared from micronized soybean protein in Examples 1-3 and the comparative examples before heating.

[0038] Figure 4 Viscosity curves of micronized soybean protein dispersions prepared from micronized soybean protein in Examples 1-3 and the comparative examples after heating.

[0039] Figure 5 This is a SEM image of the micronized soybean protein in Example 2.

[0040] Figure 6 This is a SEM image of the micronized soybean protein in Example 3.

[0041] Figure 7 This is a SEM image of micronized soybean protein in the comparative example. Detailed Implementation

[0042] The present invention will be further explained and described below with reference to specific embodiments.

[0043] Example 1:

[0044] A micronized soybean protein, the preparation method of which is as follows:

[0045] 1) Add 100g of defatted soybean meal to 1000mL of deionized water and stir for 1h at room temperature and 500rpm. Then add 2mol / L sodium hydroxide solution to adjust the pH to 7.0 to obtain soybean meal dispersion.

[0046] 2) Add the soybean meal dispersion to a centrifuge, adjust the centrifuge speed to 8000 rpm, centrifuge for 15 min, take the clear liquid and add 2 mol / L hydrochloric acid solution to adjust the pH value to 6.0 to obtain soybean protein clear liquid;

[0047] 3) Heat the soybean protein solution to 75°C, then add 0.1% of papain based on the solid content of the soybean protein solution, keep warm and stir for 30 minutes, then keep warm in a 95°C water bath for 5 minutes, and then cool to room temperature in ice water to obtain a micronized soybean protein dispersion.

[0048] 4) Add the micronized soybean protein dispersion to a centrifuge, adjust the centrifuge speed to 5000 rpm, centrifuge for 5 min, and take the solids to obtain micronized soybean protein curd.

[0049] 5) Add twice the mass of deionized water to the micronized soybean protein curd and stir to disperse. Then add a 2 mol / L sodium hydroxide solution to adjust the pH to 6.0. Then spray dry the product. The spray drying parameters are: inlet air temperature 180℃, outlet air temperature 90℃, and injection rate 4.5 mL / min to obtain micronized soybean protein.

[0050] Performance testing:

[0051] 1) The scanning electron microscope (SEM) image of the micronized soybean protein in this embodiment is shown below. Figure 1 As shown.

[0052] Depend on Figure 1It can be seen that the micronized soybean protein in this embodiment is irregular solid spheres with a particle size of 1μm to 8μm. The particle size distribution is relatively uniform, concentrated at about 4μm, showing excellent dispersibility.

[0053] 2) The polyacrylamide gel electrophoresis (SDS-PAGE) image of the micronized soy protein in this embodiment is shown below. Figure 2 As shown.

[0054] Depend on Figure 2 It can be seen that the protein composition of the micronized soybean protein in this embodiment is 11S and small molecule peptides.

[0055] 3) The micronized soybean protein in this embodiment was prepared into a 10% (w / w) micronized soybean protein dispersion using deionized water. The viscosity of the micronized soybean protein dispersion before and after heating at 95°C for 30 min was then measured using a rheometer. The viscosity curves of the micronized soybean protein dispersion before and after heating at different shear rates are shown below. Figure 3 (before heating) and Figure 4 As shown (after heating).

[0056] Depend on Figure 3 and Figure 4 It can be seen that the micronized soybean protein dispersion in this embodiment still exhibits a low viscosity (0.043 Pa·s) after heat treatment, indicating that the micronized soybean protein has excellent thermal stability.

[0057] Example 2:

[0058] A micronized soybean protein, the preparation method of which is as follows:

[0059] 1) Add 80g of defatted soybean meal to 1000mL of deionized water and stir for 1.5h at room temperature and 400rpm. Then add 2mol / L sodium hydroxide solution to adjust the pH to 7.0 to obtain soybean meal dispersion.

[0060] 2) Add the soybean meal dispersion to a centrifuge, adjust the centrifuge speed to 8000 rpm, centrifuge for 15 min, take the clear liquid and add 2 mol / L hydrochloric acid solution to adjust the pH value to 6.0 to obtain soybean protein clear liquid;

[0061] 3) Heat the soybean protein solution to 75°C, then add 0.02% of papain based on the solid content of the soybean protein solution, keep warm and stir for 30 minutes, then keep warm in a 95°C water bath for 5 minutes, and then cool to room temperature in ice water to obtain a micronized soybean protein dispersion.

[0062] 4) Add the micronized soybean protein dispersion to a centrifuge, adjust the centrifuge speed to 5000 rpm, centrifuge for 5 min, and take the solids to obtain micronized soybean protein curd.

[0063] 5) Add 3 times the mass of deionized water to the micronized soybean protein curd and stir to disperse. Then add 2 mol / L sodium hydroxide solution to adjust the pH value to 6.0. Then spray dry the product. The spray drying operation parameters are: inlet air temperature 180℃, outlet air temperature 100℃, and injection rate 3.5 mL / min to obtain micronized soybean protein.

[0064] Performance testing:

[0065] 1) The SEM image of the micronized soybean protein in this embodiment is shown below. Figure 5 As shown.

[0066] Depend on Figure 5 It can be seen that the micronized soybean protein in this embodiment is irregular solid spheres with a particle size of 1μm to 8μm. The particle size distribution is relatively uniform, concentrated at about 5μm, showing excellent dispersibility.

[0067] 2) The results of polyacrylamide gel electrophoresis (SDS-PAGE) showed that the protein composition of the micronized soybean protein in this example was 11S and small molecule peptides.

[0068] 3) The micronized soybean protein in this embodiment was prepared into a 10% (w / w) micronized soybean protein dispersion using deionized water. The viscosity of the micronized soybean protein dispersion before and after heating at 90°C for 30 min was then measured using a rheometer. The viscosity curves of the micronized soybean protein dispersion before and after heating at different shear rates are shown below. Figure 3 (before heating) and Figure 4 As shown (after heating).

[0069] Depend on Figure 3 and Figure 4 It can be seen that the micronized soybean protein dispersion in this embodiment still exhibits a low viscosity (0.018 Pa·s) after heat treatment, indicating that the micronized soybean protein has excellent thermal stability.

[0070] Example 3:

[0071] A micronized soybean protein, the preparation method of which is as follows:

[0072] 1) Add 60g of defatted soybean meal to 500mL of deionized water and stir for 1h at room temperature and 200rpm. Then add 2mol / L sodium hydroxide solution to adjust the pH to 7.5 to obtain soybean meal dispersion.

[0073] 2) Add the soybean meal dispersion to a centrifuge, adjust the centrifuge speed to 8000 rpm, centrifuge for 15 min, take the clear liquid and add 2 mol / L hydrochloric acid solution to adjust the pH value to 6.5 to obtain soybean protein clear liquid;

[0074] 3) Heat the soybean protein solution to 75°C, then add 0.1% ginger protease based on the solid content of the soybean protein solution, keep warm and stir for 30 minutes, then keep warm in a 100°C water bath for 5 minutes, and then cool to room temperature in ice water to obtain micronized soybean protein dispersion.

[0075] 4) Add the micronized soybean protein dispersion to a centrifuge, adjust the centrifuge speed to 5000 rpm, centrifuge for 5 min, and take the solids to obtain micronized soybean protein curd.

[0076] 5) Add 2.5 times the mass of deionized water to the micronized soybean protein curd and stir to disperse. Then add 2 mol / L sodium hydroxide solution to adjust the pH value to 6.0. Then spray dry the product. The spray drying operation parameters are: inlet air temperature 180℃, outlet air temperature 100℃, and injection rate 3.5 mL / min to obtain micronized soybean protein.

[0077] Performance testing:

[0078] 1) The SEM image of the micronized soybean protein in this embodiment is shown below. Figure 6 As shown.

[0079] Depend on Figure 6 It can be seen that the micronized soybean protein in this embodiment is irregular solid spheres with a particle size of 1μm to 6μm. The particle size distribution is relatively uniform, concentrated at about 4μm, showing excellent dispersibility.

[0080] 2) The polyacrylamide gel electrophoresis (SDS-PAGE) image of the micronized soy protein in this embodiment is shown below. Figure 2 As shown.

[0081] Depend on Figure 2 It can be seen that the protein composition of the micronized soybean protein in this embodiment is 11S and small molecule peptides.

[0082] 3) The micronized soybean protein in this embodiment was prepared into a 10% (w / w) micronized soybean protein dispersion using deionized water. The viscosity of the micronized soybean protein dispersion before and after heating at 90°C for 30 min was then measured using a rheometer. The viscosity curves of the micronized soybean protein dispersion before and after heating at different shear rates are shown below. Figure 3 (before heating) and Figure 4 As shown (after heating).

[0083] Depend on Figure 3 and Figure 4 It can be seen that the micronized soybean protein dispersion in this embodiment still exhibits a low viscosity (0.051 Pa·s) after heat treatment, indicating that the micronized soybean protein has excellent thermal stability.

[0084] Comparative example:

[0085] A micronized soybean protein, the preparation method of which is as follows:

[0086] 1) Add 150g of defatted soybean meal to 1500mL of deionized water and stir for 1h at room temperature and 200rpm. Then add 2mol / L sodium hydroxide solution to adjust the pH to 7.0 to obtain soybean meal dispersion.

[0087] 2) Add the soybean meal dispersion to a centrifuge, adjust the centrifuge speed to 8000 rpm, centrifuge for 15 min, take the clear liquid and add 2 mol / L hydrochloric acid solution to adjust the pH value to 4.5 to obtain soybean protein clear liquid;

[0088] 3) Heat the soybean protein solution to 75°C, keep it warm and stir for 30 minutes, then place it in a 100°C water bath for 5 minutes, and then cool it in ice water to room temperature to obtain a micronized soybean protein dispersion.

[0089] 4) Add the micronized soybean protein dispersion to a centrifuge, adjust the centrifuge speed to 5000 rpm, centrifuge for 5 min, and take the solids to obtain micronized soybean protein curd.

[0090] 5) Add 2.5 times the mass of deionized water to the micronized soybean protein curd and stir to disperse. Then add 2 mol / L sodium hydroxide solution to adjust the pH value to 7.0. Then spray dry the product. The spray drying operation parameters are: inlet air temperature 180℃, outlet air temperature 100℃, and injection rate 3.5 mL / min to obtain micronized soybean protein.

[0091] Performance testing:

[0092] 1) The SEM image of the micronized soybean protein in this comparative example is shown below. Figure 7 As shown.

[0093] Depend on Figure 7 It can be seen that the micronized soybean protein in this comparative example is shriveled and hollow spheres with uneven particle size distribution, ranging from 1μm to 20μm, and has poor dispersibility.

[0094] 2) The polyacrylamide gel electrophoresis (SDS-PAGE) image of the micronized soy protein in this comparative example is shown below. Figure 2 As shown.

[0095] Depend on Figure 2 It can be seen that the protein composition of the micronized soy protein in this comparative example is consistent with that of soy protein isolate.

[0096] 3) The micronized soy protein in this comparative example was prepared into a 10% (w / w) micronized soy protein dispersion using deionized water. The viscosity of the micronized soy protein dispersion before and after heating at 90°C for 30 min was then measured using a rheometer. The viscosity curves of the micronized soy protein dispersion before and after heating at different shear rates are shown below. Figure 3 (before heating) and Figure 4 As shown (after heating).

[0097] Depend on Figure 3 and Figure 4 It can be seen that the viscosity of the micronized soybean protein dispersion in this comparative example increased by about 52 times after heat treatment, indicating poor thermal stability.

[0098] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing micronized soybean protein, characterized in that, Includes the following steps: 1) Disperse defatted soybean meal in water, then adjust the pH to 7.0–9.0 to obtain a soybean meal dispersion; 2) Centrifuge the soybean meal dispersion, take the clear liquid and adjust the pH value to 4.5-7.0 to obtain soybean protein clear liquid; 3) Add the protease to the soybean protein clear liquid for enzymatic hydrolysis and enzyme inactivation to obtain a micronized soybean protein dispersion; 4) Centrifuge the micronized soybean protein dispersion, collect the solids, and obtain micronized soybean protein curd; 5) Disperse the micronized soy protein curd with water, adjust the pH to 5.0-7.0, and then spray dry to obtain micronized soy protein; Step 3) The protease is papain or ginger protease; Step 3) The amount of protease used is 0.02% to 0.1% of the solid content of the soybean protein solution; Step 3) The enzymatic hydrolysis is carried out at a temperature of 60℃ to 85℃ for a time of 10 min to 60 min.

2. The preparation method according to claim 1, characterized in that: Step 1) The dispersion method is mechanical stirring, with the stirring speed of the stirrer being 200 rpm to 1000 rpm and the stirring time being 1 h to 3 h.

3. The preparation method according to claim 1, characterized in that: Step 3) describes an enzyme inactivation method using high-temperature inactivation.

4. The preparation method according to claim 1, characterized in that: Step 5) The mass ratio of micronized soybean protein curd to water is 1:2 to 10.

5. The preparation method according to claim 1 or 4, characterized in that: Step 5) The operating parameters for spray drying are: inlet air temperature of 160℃~200℃, outlet air temperature of 90℃~110℃, and injection rate of 1.5mL / min~4.5mL / min.

6. A micronized soy protein, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 5.

7. A food product, characterized in that, It includes the micronized soybean protein as described in claim 6.

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