阅读说明：本技术 一种速溶大豆蛋白粉及其制备方法 (Instant soybean protein powder and preparation method thereof ) 是由 刘兵 刘峰 张铭辉 陈强 张旭光 于 2021-08-26 设计创作，主要内容包括：本发明涉及豆粉加工技术领域,尤其涉及一种速溶大豆蛋白粉及其制备方法。所述制备方法包括：A)将低温脱脂豆粕和45～55℃的水混合,调节pH值为6.8～7.4,搅拌萃取后,固液分离,得到一萃液相和一萃固相；B)将一萃固相与45～55℃的水混合,搅拌萃取后,固液分离,得到二萃液相；C)将一萃液相和二萃液相混合后,调节pH值为4.4～4.6,搅拌后,固液分离,得到酸沉凝乳；将酸沉凝乳与50～70℃的水混合,进行混合解碎；D)将解碎液降温后,加水得到固含量为9％～14％的料液,调节pH值为7.0～9.0,搅拌后,杀菌和干燥,得到速溶大豆蛋白粉。本发明制备的速溶大豆蛋白粉溶解性和风味均较优。(The invention relates to the technical field of soybean powder processing, in particular to instant soybean protein powder and a preparation method thereof. The preparation method comprises the following steps: A) mixing the low-temperature defatted soybean meal with water at the temperature of 45-55 ℃, adjusting the pH value to 6.8-7.4, stirring and extracting, and performing solid-liquid separation to obtain an extraction liquid phase and an extraction solid phase; B) mixing the first extraction solid phase with water at the temperature of 45-55 ℃, stirring and extracting, and then carrying out solid-liquid separation to obtain a second extraction liquid phase; C) mixing the first extraction liquid phase and the second extraction liquid phase, adjusting the pH value to 4.4-4.6, stirring, and carrying out solid-liquid separation to obtain acid-precipitated curd; mixing the acid-precipitated curd with water at 50-70 ℃, and performing mixing and crushing; D) and cooling the disintegrating solution, adding water to obtain feed liquid with the solid content of 9-14%, adjusting the pH value to 7.0-9.0, stirring, sterilizing and drying to obtain the instant soybean protein powder. The instant soybean protein powder prepared by the invention has better dissolubility and flavor.)

1. A preparation method of instant soybean protein powder comprises the following steps:

A) mixing the low-temperature defatted soybean meal with water at the temperature of 45-55 ℃, adjusting the pH value of the mixed solution to 6.8-7.4, stirring and extracting, and carrying out solid-liquid separation to obtain an extraction liquid phase and an extraction solid phase;

B) mixing the first extraction solid phase with water at the temperature of 45-55 ℃, stirring and extracting, and then carrying out solid-liquid separation to obtain a second extraction liquid phase and a second extraction solid phase;

C) mixing the first extraction liquid phase and the second extraction liquid phase, adjusting the pH value to 4.4-4.6, stirring, and carrying out solid-liquid separation to obtain acid-precipitated curd and whey water; mixing the acid-precipitated curd with water at 50-70 ℃, and performing mixing and crushing to obtain crushing liquid;

D) cooling the disintegrating solution, adding water to obtain feed liquid with solid content of 9-14%, adjusting the pH value to 7.0-9.0, and stirring to obtain neutralized protein slurry;

E) and sterilizing and drying the neutralized protein slurry to obtain the instant soybean protein powder.

2. The preparation method according to claim 1, wherein in the step A), the mass ratio of the low-temperature defatted soybean meal to water at 45-55 ℃ is 1: 6-9;

adjusting the pH value of the mixed solution by adopting liquid alkali as a reagent;

the stirring and extraction time is 20-40 min.

3. The preparation method according to claim 1, wherein in the step B), the mass ratio of the first extraction solid phase to water at 45-55 ℃ is 1: 4-5;

the stirring extraction time is 20-40 min.

4. The method according to claim 1, wherein in step C), the stirring speed is 50-200 rpm/min for 5-15 min.

5. The preparation method according to claim 1, wherein in the step C), the mass ratio of the acid-precipitated curd to water at 50-70 ℃ is 1: 6-10;

the rotating speed of the mixing and crushing is 100-500 rpm/min.

6. The preparation method according to claim 1, wherein in the step D), the temperature after cooling is 15-20 ℃;

the cooling rate is 6-10 ℃/min;

the reagent used for adjusting the pH value is liquid alkali.

7. The preparation method according to claim 1, wherein in the step D), the rotation speed of the stirring is 100-500 rpm/min, and the time is 60-90 min;

step D) is carried out in a neutralization tank;

in the stirring process, after the liquid level in the neutralization tank exceeds 50%, heating to 60-80 ℃ by using steam, and homogenizing and shearing the materials by using a neutralization circulating mill to obtain neutralized protein slurry;

the grinding frequency of the neutralization circulating mill is 33-36 Hz, and the homogenizing and shearing time is 45-60 min.

8. The method for preparing according to claim 1, wherein in step E), the sterilizing comprises:

carrying out instantaneous sterilization for 3 times and 8 seconds at the temperature of 130-160 ℃;

after the sterilization, the method further comprises the following steps: reducing the pressure and the temperature of the sterilized protein liquid in a flash tank, and homogenizing the obtained flash liquid at high pressure;

the pressure in the flash tank is controlled to be-80 to-76 kPa.

9. The method according to claim 1, wherein in step E), the drying is spray drying;

the air inlet temperature of the spray drying is more than or equal to 175 ℃, and the air outlet temperature is 65-120 ℃;

after the drying is finished, the method further comprises the following steps:

cooling the dried material, adding phospholipid, and performing spray granulation to obtain instant soybean protein powder;

the mass ratio of the phospholipid to the dried material is 0.2-2 per mill.

10. The instant soybean protein powder prepared by the preparation method of any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of soybean powder processing, in particular to instant soybean protein powder and a preparation method thereof.

Background

The soybean protein has the effects of reducing blood fat, preventing osteoporosis and the like, and in addition, the soybean protein has reasonable amino acid composition, is similar to milk protein and chicken protein, and is high-quality protein in vegetable protein. In addition, the soybean protein has strong water holding capacity, has satiety effect when being eaten, and is a good meal replacement food for weight managers. However, soy protein has problems of poor flavor and poor dispersibility during application: for a soybean protein solid powder product, the soybean protein solid powder product is generally drunk by being brewed with water, in the brewing process, due to the hydrophilic characteristic of the surface of the soybean protein, insoluble lumps similar to fish eyes or insoluble powder packets are easily formed, the drinking mouthfeel of a client is seriously influenced by the formation of the insoluble lumps, and very poor application experience is brought; in addition, in the production process of the soybean protein, after the soybean cells are broken, substances of aldehydes, alcohols and ketones generated by the oxidation of oil bodies in the cells are combined with the protein, so that the soybean protein generates some bad flavors. These off-flavors also severely impact the space of application of soy protein.

The soybean protein isolate is produced mainly by an alkali-dissolving and acid-precipitating process, and is a method for dissolving glycinin and beta-conglycinin under an alkaline condition, separating bean dregs, and precipitating the soybean protein from the obtained solution under the condition of pH 4.5. The main steps are low-temperature edible soybean meal → extraction → acid precipitation → neutralization → sterilization → drying → packaging → metal detection → inspection → warehousing.

Currently, known methods for improving the dispersibility of soy protein are the addition of dextrin or emulsifiers, which introduce foreign substances that increase the risk of the product. In addition, emulsifying agents, mainly oil and fat substances, are added, and the substances are oxidized in the storage process of the product to generate poor flavor substances, so that the flavor of the final product is influenced.

Known methods for improving the flavor of soy protein include a method using alcohol washing, but the method has a drawback that the solubility of soy protein is remarkably reduced; in addition, the dispersibility is improved by adding calcium or magnesium compounds, and because the protein carries charges, the addition of the divalent ions easily causes the aggregation of the protein, thereby reducing the dissolution stability of the product.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide an instant soybean protein powder and a preparation method thereof, wherein the instant soybean protein powder prepared by the present invention has excellent solubility and flavor.

The invention provides a preparation method of instant soybean protein powder, which comprises the following steps:

A) mixing the low-temperature defatted soybean meal with water at the temperature of 45-55 ℃, adjusting the pH value of the mixed solution to 6.8-7.4, stirring and extracting, and carrying out solid-liquid separation to obtain an extraction liquid phase and an extraction solid phase;

B) mixing the first extraction solid phase with water at the temperature of 45-55 ℃, stirring and extracting, and then carrying out solid-liquid separation to obtain a second extraction liquid phase and a second extraction solid phase;

C) mixing the first extraction liquid phase and the second extraction liquid phase, adjusting the pH value to 4.4-4.6, stirring, and carrying out solid-liquid separation to obtain acid-precipitated curd and whey water; mixing the acid-precipitated curd with water at 50-70 ℃, and performing mixing and crushing to obtain crushing liquid;

D) cooling the disintegrating solution, adding water to obtain feed liquid with solid content of 9-14%, adjusting the pH value to 7.0-9.0, and stirring to obtain neutralized protein slurry;

E) and sterilizing and drying the neutralized protein slurry to obtain the instant soybean protein powder.

Preferably, in the step A), the mass ratio of the low-temperature defatted soybean meal to water at 45-55 ℃ is 1: 6-9;

adjusting the pH value of the mixed solution by adopting liquid alkali as a reagent;

the stirring and extraction time is 20-40 min.

Preferably, in the step B), the mass ratio of the first extraction solid phase to water at 45-55 ℃ is 1: 4-5;

the stirring extraction time is 20-40 min.

Preferably, in the step C), the rotation speed of the stirring is 50-200 rpm/min, and the time is 5-15 min.

Preferably, in the step C), the mass ratio of the acid-precipitated curd to water at 50-70 ℃ is 1: 6-10;

the rotating speed of the mixing and crushing is 100-500 rpm/min.

Preferably, in the step D), the temperature after cooling is 15-20 ℃;

the cooling rate is 6-10 ℃/min;

the reagent used for adjusting the pH value is liquid alkali.

Preferably, in the step D), the rotating speed of the stirring is 100-500 rpm/min, and the time is 60-90 min;

step D) is carried out in a neutralization tank;

in the stirring process, after the liquid level in the neutralization tank exceeds 50%, heating to 60-80 ℃ by using steam, and homogenizing and shearing the materials by using a neutralization circulating mill to obtain neutralized protein slurry;

the grinding frequency of the neutralization circulating mill is 33-36 Hz, and the homogenizing and shearing time is 45-60 min.

Preferably, in step E), the sterilization includes:

carrying out instantaneous sterilization for 3 times and 8 seconds at the temperature of 130-160 ℃;

after the sterilization, the method further comprises the following steps: reducing the pressure and the temperature of the sterilized protein liquid in a flash tank, and homogenizing the obtained flash liquid at high pressure;

the pressure in the flash tank is controlled to be-80 to-76 kPa.

Preferably, in step E), the drying is spray drying;

the air inlet temperature of the spray drying is more than or equal to 175 ℃, and the air outlet temperature is 65-120 ℃;

after the drying is finished, the method further comprises the following steps:

cooling the dried material, adding phospholipid, and performing spray granulation to obtain instant soybean protein powder;

the mass ratio of the phospholipid to the dried material is 0.2-2 per mill.

The invention also provides instant soybean protein powder prepared by the preparation method.

The invention provides a preparation method of instant soybean protein powder, which comprises the following steps: A) mixing the low-temperature defatted soybean meal with water at the temperature of 45-55 ℃, adjusting the pH value of the mixed solution to 6.8-7.4, stirring and extracting, and carrying out solid-liquid separation to obtain an extraction liquid phase and an extraction solid phase; B) mixing the first extraction solid phase with water at the temperature of 45-55 ℃, stirring and extracting, and then carrying out solid-liquid separation to obtain a second extraction liquid phase and a second extraction solid phase; C) mixing the first extraction liquid phase and the second extraction liquid phase, adjusting the pH value to 4.4-4.6, stirring, and carrying out solid-liquid separation to obtain acid-precipitated curd and whey water; mixing the acid-precipitated curd with water at 50-70 ℃, and performing mixing and crushing to obtain crushing liquid; D) cooling the disintegrating solution, adding water to obtain feed liquid with solid content of 9-14%, adjusting the pH value to 7.0-9.0, and stirring to obtain neutralized protein slurry; E) and sterilizing and drying the neutralized protein slurry to obtain the instant soybean protein powder. The instant soybean protein powder prepared by the invention has excellent solubility and flavor, and simultaneously, as no foreign substances are introduced, the purity of the product is effectively ensured.

Drawings

FIG. 1 is a GC spectrum of instant soy protein powder of example 1 of the present invention and a comparative example;

FIG. 2 is a GC spectrum of instant soy protein powder of example 2 of the present invention and a comparative example;

fig. 3 is a GC spectrum of instant soy protein powder of example 3 of the present invention and a comparative example.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a preparation method of instant soybean protein powder, which comprises the following steps:

A) mixing the low-temperature defatted soybean meal with water at the temperature of 45-55 ℃, adjusting the pH value of the mixed solution to 6.8-7.4, stirring and extracting, and carrying out solid-liquid separation to obtain an extraction liquid phase and an extraction solid phase;

B) mixing the first extraction solid phase with water at the temperature of 45-55 ℃, stirring and extracting, and then carrying out solid-liquid separation to obtain a second extraction liquid phase and a second extraction solid phase;

C) mixing the first extraction liquid phase and the second extraction liquid phase, adjusting the pH value to 4.4-4.6, stirring, and carrying out solid-liquid separation to obtain acid-precipitated curd and whey water; mixing the acid-precipitated curd with water at 50-70 ℃, and performing mixing and crushing to obtain crushing liquid;

D) cooling the disintegrating solution, adding water to obtain feed liquid with solid content of 9-14%, adjusting the pH value to 7.0-9.0, and stirring to obtain neutralized protein slurry;

E) and sterilizing and drying the neutralized protein slurry to obtain the instant soybean protein powder.

The method comprises the steps of mixing low-temperature defatted soybean meal with water at 45-55 ℃, adjusting the pH value of a mixed solution to 6.8-7.4, stirring and extracting, and carrying out solid-liquid separation to obtain a first extraction liquid phase and a first extraction solid phase.

In certain embodiments of the invention, the mass ratio of the low-temperature defatted soybean meal to water at 45-55 ℃ is 1: 6-9. In certain embodiments, the mass ratio of the low-temperature defatted soybean meal to water at 45-55 ℃ is 1: 8.

in certain embodiments of the invention, the temperature of the water is 50 ℃.

In some embodiments of the present invention, the reagent used to adjust the pH of the mixed liquor is liquid alkali.

In some embodiments of the present invention, the rotation speed of the stirring extraction is 50 to 200 rpm/min. In certain embodiments, the rotational speed of the agitated extraction is 100 rpm/min.

In some embodiments of the present invention, the stirring and extracting time is 20-40 min. In some embodiments, the stirring extraction time is 25-30 min or 28 min.

In certain embodiments of the invention, the method of solid-liquid separation is centrifugation.

And (3) after a first extraction liquid phase and a first extraction solid phase are obtained, mixing the first extraction solid phase with water at the temperature of 45-55 ℃, stirring and extracting, and then carrying out solid-liquid separation to obtain a second extraction liquid phase and a second extraction solid phase.

In some embodiments of the invention, the mass ratio of the first extraction solid phase to the water at 45-55 ℃ is 1: 4 to 5. In some embodiments, the mass ratio of the first extraction phase to water at 45-55 ℃ is 1: 5.

in certain embodiments of the invention, the temperature of the water is 50 ℃.

In some embodiments of the present invention, the rotation speed of the stirring extraction is 50 to 200 rpm/min. In certain embodiments, the rotational speed of the agitated extraction is 100 rpm/min.

In some embodiments of the present invention, the stirring and extracting time is 20-40 min. In certain embodiments, the time for the agitated extraction is 20 min.

In certain embodiments of the invention, the method of solid-liquid separation is centrifugation.

After a secondary extraction liquid phase and a secondary extraction solid phase are obtained, acid precipitation is carried out, and the method specifically comprises the following steps: mixing the first extraction liquid phase and the second extraction liquid phase, adjusting the pH value to 4.4-4.6, stirring, and carrying out solid-liquid separation to obtain acid-precipitated curd and whey water; and mixing the acid-precipitated curd with water at 50-70 ℃, and mixing and disintegrating to obtain a disintegrating solution.

In some embodiments of the present invention, the reagent used to adjust the pH of the mixed liquor is hydrochloric acid. In certain embodiments of the invention, the pH is adjusted to 4.45.

In some embodiments of the present invention, the rotation speed of the stirring is 50 to 200rpm/min, and in some embodiments, the rotation speed of the stirring is 100 rpm/min.

In some embodiments of the invention, the stirring time is 5-15 min. In certain embodiments, the time of stirring is 10 min.

In certain embodiments of the invention, the method of solid-liquid separation is centrifugation.

In certain embodiments of the invention, the mass ratio of the acid-precipitated curd to water at 50-70 ℃ is 1: 6 to 10. In certain embodiments, the mass ratio of the acid-precipitated curd to water at 50-70 ℃ is 1: 7.

in certain embodiments of the invention, the temperature of the water mixed with the acid-precipitated curd is 60 ℃ or 65 ℃.

In some embodiments of the present invention, the rotation speed of the mixing and disintegrating is 100-500 rpm/min. In certain embodiments of the invention, the rotational speed of the agitated extraction is 200 rpm/min.

The invention mixes acid-precipitated curd with water of 50-70 ℃, and utilizes heating to stretch the structure of the soybean protein, thereby destroying the cohesion of the protein, reducing the gel property and reducing the inclusion effect on beany flavor substances.

After obtaining the disintegration liquid, neutralizing the disintegration liquid, and specifically comprising: and cooling the disintegrating solution, adding water to obtain feed liquid with the solid content of 9-14%, adjusting the pH value to 7.0-9.0, and stirring to obtain the neutralized protein slurry.

In some embodiments of the invention, plate heat exchangers may be used for desuperheating. In some embodiments of the invention, the temperature after cooling is 15-20 ℃ or 20 ℃. In some embodiments of the invention, the cooling rate is 6-10 ℃/min to help protein molecules shrink and improve the acid precipitation effect. In certain embodiments, the rate of cooling is 8 ℃/min.

In certain embodiments of the invention, the feed solution has a solids content of 12% to 14%, 12.5%, or 14%.

In certain embodiments of the invention, the agent used to adjust the pH is a liquid base. In certain embodiments, the pH is adjusted to 7.2.

In some embodiments of the present invention, the rotation speed of the stirring is 100 to 500 rpm/min. In certain embodiments of the invention, the rotational speed of the agitation is 200 rpm/min. In some embodiments of the invention, the stirring time is 60-90 min.

In certain embodiments of the invention, the neutralization is carried out in a neutralization tank.

In some embodiments of the invention, in the stirring process, after the liquid level in the neutralization tank exceeds 50%, steam is used for heating to 60-80 ℃, and the materials are subjected to homogenizing and shearing through a neutralization circulating mill to obtain neutralized protein slurry.

In certain embodiments of the invention, steam is used to heat to 65 ℃, 70 ℃, or 75 ℃.

In some embodiments of the invention, the frequency of the neutralization and circulation mill is 33-36 Hz, and the time of the homogeneous shearing is 45-60 min. In certain embodiments, the frequency of the neutralization cycle mill is 34 Hz. In certain embodiments, the time for homogenizing shear of the neutralization rotary mill is 50 min.

The material in the neutralization tank is heated by steam, so that the activity of the soybean protein can be destroyed, the NSI value is reduced, and the instant effect is improved; and then the emulsification effect of the product can be further improved by carrying out homogeneous shearing through a neutralization circulating mill. In certain embodiments of the invention, the homogenizing shear is performed by a fine homogenizer.

And after the neutralized protein slurry is obtained, sterilizing and drying the neutralized protein slurry to obtain the instant soybean protein powder.

In certain embodiments of the invention, the sterilizing comprises:

performing instantaneous sterilization for 3 times and 8 seconds at 130-160 ℃.

In certain embodiments of the present invention, the neutralized protein slurry is passed through a pressure pump into an ultra high temperature jet cooker sterilizer for sterilization.

In some embodiments of the invention, the pump frequency of the booster pump is 30-36 Hz.

In some embodiments of the present invention, the sterilization temperature is 140-145 ℃ or 142 ℃.

In some embodiments of the present invention, after the sterilizing, further comprising: and (4) reducing the pressure and the temperature of the sterilized protein liquid in a flash tank, and homogenizing the obtained flash liquid at high pressure.

In certain embodiments of the invention, the pressure in the flash tank is controlled between-80 and-76 kPa or-78 kPa.

In some embodiments of the present invention, the high-pressure homogenizing high-pressure pump has a pressure of 15 to 20MPa and a homogenizing pressure of 8 to 12 MPa. In some embodiments, the high-pressure homogenizing high-pressure pump has a pressure of 15-17 MPa and the homogenizing pressure is 8-10 MPa. In certain embodiments, the high pressure homogenization is performed in a high pressure homogenizer.

In certain embodiments of the invention, the drying is spray drying. The air inlet temperature of the spray drying is more than or equal to 175 ℃, and the air outlet temperature is 65-120 ℃. In certain embodiments, the spray-drying has an inlet air temperature of 175 ℃ and an outlet air temperature of 70 ℃.

In some embodiments of the present invention, after the drying is completed, the method further comprises:

and cooling the dried material, adding phospholipid, and performing spray granulation to obtain the instant soybean protein powder.

The cooling method is not particularly limited, and the low-speed propeller can be stirred and cooled to room temperature in a finished product bin, wherein the rotating speed of the low-speed propeller is 50 rpm/min.

In certain embodiments of the invention, the mass ratio of the phospholipid to the dried material is between 0.2% and 2%. In certain embodiments, the mass ratio of the phospholipid to the dried material is 1% o.

The source of the above-mentioned raw materials is not particularly limited in the present invention, and may be generally commercially available.

The invention adopts a physical heating method to improve the dispersibility and the flavor of the product, effectively avoids the introduction of foreign substances and ensures the purity of the product.

The invention also provides instant soybean protein powder prepared by the preparation method. The instant soybean protein powder prepared by the invention has excellent solubility and flavor, and simultaneously, as no foreign substances are introduced, the purity of the product is effectively ensured.

In order to further illustrate the present invention, the instant soybean protein powder and the preparation method thereof provided by the present invention will be described in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.

Example 1

1. And (3) extraction: the low-temperature defatted soybean meal and water at 50 ℃ are mixed according to the mass ratio of 1: 8, mixing, adjusting the pH to 7.2 by using liquid alkali, stirring at a constant speed (100rpm/min) for 28min, and performing centrifugal separation to obtain an extraction liquid phase and an extraction solid phase; adding 5 times of water (50 deg.C) again into the first extraction solid phase, stirring at constant speed (100rpm/min) for 20min, and centrifuging to obtain second extraction liquid phase and second extraction solid phase.

2. Acid precipitation: mixing the first extraction liquid phase and the second extraction liquid phase, adjusting pH to 4.45 with hydrochloric acid, stirring at low speed of 100rpm/min for 10min, and centrifuging to obtain acid-precipitated curd and whey water; adding water of 60 deg.C (the mass ratio of acid-precipitated milk curd to water of 60 deg.C is 1:7), and mixing and disintegrating with high-speed propeller at 200rpm/min to obtain disintegrating solution.

3. Neutralizing: rapidly reducing the temperature of the disintegrating liquid to 20 ℃ by adopting a plate heat exchanger (the temperature reduction rate is 8 ℃/min), adding water to obtain feed liquid with the solid content of 12.5%, pumping the feed liquid into a neutralization tank, adding liquid alkali to adjust the pH to 7.2, stirring at the rotating speed of 200rpm/min, heating the feed liquid to 65 ℃ by utilizing steam after the liquid level in the tank exceeds 50%, and carrying out homogenization and shearing on the feed liquid for 50min by utilizing a neutralization circulating mill (the milling frequency is 34Hz) to obtain aged protein slurry.

4. And (3) sterilization: feeding the protein slurry obtained in the neutralization section into an ultrahigh-temperature jet-boiling sterilization machine through a pressure pump, sequentially carrying out instantaneous sterilization for 3 times and 8 seconds at the high temperature of 142 ℃, reducing the pressure and the temperature of the sterilized protein liquid in a flash tank, and controlling the pressure in the flash tank to be-78 kPa; homogenizing the obtained flash evaporation liquid at high pressure; the pressure intensity of a high-pressure pump of the high-pressure homogenizer is 16MPa, and the homogenizing pressure intensity is 8 MPa.

5. And (3) drying: and (3) carrying out spray drying, wherein the air inlet temperature of the spray drying is 175 ℃, and the air outlet temperature of the spray drying is 70 ℃, so as to obtain the instant soybean protein powder.

Example 2

1. And (3) extraction: the low-temperature defatted soybean meal and water at 50 ℃ are mixed according to the mass ratio of 1: 8, mixing, adjusting the pH to 7.2 by using liquid alkali, stirring at a constant speed (100rpm/min) for 28min, and performing centrifugal separation to obtain an extraction liquid phase and an extraction solid phase; adding 5 times of water (50 deg.C) again into the first extraction solid phase, stirring at constant speed (100rpm/min) for 20min, and centrifuging to obtain second extraction liquid phase and second extraction solid phase.

2. Acid precipitation: mixing the first extraction liquid phase and the second extraction liquid phase, adjusting pH to 4.45 with hydrochloric acid, stirring at low speed of 100rpm/min for 10min, and centrifuging to obtain acid-precipitated curd and whey water; adding 65 ℃ water (the mass ratio of the acid-precipitated curd to the 60 ℃ water is 1:7) into the acid-precipitated milk, and mixing and disintegrating by using high-speed propeller at 200rpm/min to obtain a disintegrating solution.

3. Neutralizing: rapidly reducing the temperature of the disintegrating liquid to 20 ℃ by adopting a plate heat exchanger (the temperature reduction rate is 8 ℃/min), adding water to obtain feed liquid with the solid content of 14%, pumping the feed liquid into a neutralization tank, adding liquid alkali to adjust the pH to 7.2, stirring at the rotating speed of 200rpm/min, heating the feed liquid to 70 ℃ by utilizing steam after the liquid level in the tank exceeds 50%, and carrying out homogenization and shearing on the feed liquid for 50min by utilizing a neutralization circulating mill (the milling frequency is 34Hz) to obtain the aged protein slurry.

4. And (3) sterilization: feeding the protein slurry obtained in the neutralization section into an ultrahigh-temperature jet-boiling sterilization machine through a pressure pump, sequentially carrying out instantaneous sterilization for 3 times and 8 seconds at the high temperature of 142 ℃, reducing the pressure and the temperature of the sterilized protein liquid in a flash tank, and controlling the pressure in the flash tank to be-78 kPa; homogenizing the obtained flash evaporation liquid at high pressure; the pressure of a high-pressure pump of the high-pressure homogenizer is 17MPa, and the homogenizing pressure is 10 MPa.

5. And (3) drying: and (3) carrying out spray drying, wherein the air inlet temperature of the spray drying is 175 ℃, and the air outlet temperature of the spray drying is 70 ℃, so as to obtain the instant soybean protein powder.

Example 3

1. And (3) extraction: the low-temperature defatted soybean meal and water at 50 ℃ are mixed according to the mass ratio of 1: 8, mixing, adjusting the pH to 7.2 by using liquid alkali, stirring at a constant speed (100rpm/min) for 28min, and performing centrifugal separation to obtain an extraction liquid phase and an extraction solid phase; adding 5 times of water (50 deg.C) again into the first extraction solid phase, stirring at constant speed (100rpm/min) for 20min, and centrifuging to obtain second extraction liquid phase and second extraction solid phase.

2. Acid precipitation: mixing the first extraction liquid phase and the second extraction liquid phase, adjusting pH to 4.45 with hydrochloric acid, stirring at low speed of 100rpm/min for 10min, and centrifuging to obtain acid-precipitated curd and whey water; adding 65 ℃ water (the mass ratio of the acid-precipitated curd to the 60 ℃ water is 1:7) into the acid-precipitated milk, and mixing and disintegrating by using high-speed propeller at 200rpm/min to obtain a disintegrating solution.

3. Neutralizing: rapidly reducing the temperature of the disintegrating liquid to 20 ℃ by adopting a plate heat exchanger (the temperature reduction rate is 8 ℃/min), adding water to obtain feed liquid with the solid content of 14%, pumping the feed liquid into a neutralization tank, adding liquid alkali to adjust the pH to 7.2, stirring at the rotating speed of 200rpm/min, heating the feed liquid to 75 ℃ by utilizing steam after the liquid level in the tank exceeds 50%, and homogenizing and shearing the feed liquid for 50min by a neutralization circulating mill (the milling frequency is 34Hz) to obtain aged protein slurry.

4. And (3) sterilization: feeding the protein slurry obtained in the neutralization section into an ultrahigh-temperature jet-boiling sterilization machine through a pressure pump, sequentially carrying out instantaneous sterilization for 3 times and 8 seconds at the high temperature of 142 ℃, reducing the pressure and the temperature of the sterilized protein liquid in a flash tank, and controlling the pressure in the flash tank to be-78 kPa; homogenizing the obtained flash evaporation liquid at high pressure; the pressure of a high-pressure pump of the high-pressure homogenizer is 17MPa, and the homogenizing pressure is 10 MPa.

5. And (3) drying: and (3) carrying out spray drying, wherein the air inlet temperature of the spray drying is 175 ℃, the air exhaust temperature of the spray drying is 70 ℃, the dried material is stirred and cooled to room temperature in a finished product bin at a low speed by a propeller at a rotating speed of 50rpm/min, adding phospholipid for spray granulation, and the mass ratio of the phospholipid to the dried material is 1 per mill to obtain the instant soybean protein powder.

Comparative example

1. And (3) extraction: the low-temperature defatted soybean meal and water at 50 ℃ are mixed according to the mass ratio of 1: 8, mixing, adjusting the pH to 7.2 by using liquid alkali, stirring at a constant speed (100rpm/min) for 28min, and performing centrifugal separation to obtain an extraction liquid phase and an extraction solid phase; adding 5 times of water (50 deg.C) again into the first extraction solid phase, stirring at constant speed (100rpm/min) for 20min, and centrifuging to obtain second extraction liquid phase and second extraction solid phase.

2. Acid precipitation: mixing the first extraction liquid phase and the second extraction liquid phase, adjusting pH to 4.45 with hydrochloric acid, stirring at low speed of 100rpm/min for 10min, and centrifuging to obtain acid-precipitated curd and whey water; adding water at normal temperature (the mass ratio of acid-precipitated curd to water is 1:7) into the acid-precipitated curd, and mixing and disintegrating with high-speed propeller at 200rpm/min to obtain disintegrating liquid.

3. Neutralizing: and adding water into the disintegrating liquid to obtain a feed liquid with the solid content of 10%, pumping the feed liquid into a neutralization tank, adding liquid alkali to adjust the pH to 7.6, stirring at the rotating speed of 200rpm/min, after the liquid level in the tank exceeds 50%, performing neutralization circulating grinding (the grinding frequency is 34Hz), and performing homogenizing shearing for 50min to obtain the aged protein slurry.

4. And (3) sterilization: feeding the protein slurry obtained in the neutralization section into an ultrahigh-temperature jet-boiling sterilization machine through a pressure pump, sequentially carrying out instantaneous sterilization for 3 times and 8 seconds at the high temperature of 142 ℃, reducing the pressure and the temperature of the sterilized protein liquid in a flash tank, and controlling the pressure in the flash tank to be-78 kPa; homogenizing the obtained flash evaporation liquid at high pressure; the pressure of a high-pressure pump of the high-pressure homogenizer is 17MPa, and the homogenizing pressure is 10 MPa.

5. And (3) drying: and (3) carrying out spray drying, wherein the air inlet temperature of the spray drying is 175 ℃, and the air outlet temperature of the spray drying is 70 ℃, so as to obtain the instant soybean protein powder.

Detecting the flavor improvement effect:

the flavor of the instant soybean protein powder of the examples 1-3 and the comparative example is evaluated by using HS-SPME-GC-MS, and the protein powder to be tested and distilled water are prepared into the instant soybean protein powder with a solid-to-liquid ratio of 1: 10(w/w) of protein liquid, placing 4mL of the protein liquid in an extraction bottle, placing a rotor, sealing, placing the extraction bottle in a 50 ℃ water bath kettle, and magnetically separating and stirring the extraction bottle at the stirring speed of 600rpm/min for the balance time of 20 min; inserting the fiber head of the aged solid-phase micro-extraction needle into a headspace adsorption bottle to adsorb flavor substances for 30min at the adsorption temperature of 50 ℃, and then injecting samples without shunting; the GC-MS condition is set as the initial temperature of 30 ℃, the temperature is kept for 3min, then the temperature is raised to 100 ℃ at the speed of 6 ℃/min, the temperature is raised to 230 ℃ at the speed of 10 ℃/min, and the temperature is kept for 7 min; the ion source temperature is 200 ℃, the injection port temperature is 250 ℃, the electron energy is 70ev, and the scanning range m/z is 33-350; the gas chromatography column was DB-WAX (60m 0.25mm, 0.25 μm).

GC spectrums of the instant soybean protein powder obtained in the examples 1-3 and the comparative example are shown in figures 1-3. Fig. 1 is a GC spectrum of instant soy protein powder of example 1 of the present invention and a comparative example. Fig. 2 is a GC spectrum of instant soy protein powder of example 2 of the present invention and a comparative example. Fig. 3 is a GC spectrum of instant soy protein powder of example 3 of the present invention and a comparative example.

The peak area ratios of the main flavor substances of the instant soybean protein powders of examples 1 to 3 and the comparative example were obtained and are shown in table 1.

TABLE 1 Peak area ratio of major flavor substances of instant soybean protein powders of examples 1 to 3 and comparative example

From the analysis of the peak areas of the main flavor substances in Table 1, the hexanal and octanal are reduced by about 50% in example 1, the (E, E)2, 4-decadienal and 2-heptenal are reduced by about 20%, and other beany flavor substances are not significantly different from the comparative example; example 2 has a substantially similar beany flavor material trend as example 1, but hexanal, 1-octen-3-ol, octanal, (E, E)2, 4-decadienal and 2-heptenal have better removal than example 1; the soybean-flavored substances of example 1 and example 2 were both increased greatly, and particularly, 2-heptanone, which is a possible flavor substance derived from soybean milk flavor, was widely reported, and both examples were increased by about three times; in example 3, the decrease of characteristic flavor substances with beany flavor is most obvious, and particularly, the removal effect of hexanal with higher content can reach 90%, but the beany flavor substances are also reduced to different degrees.

Detection of dissolution improvement effect:

the dissolution effects of examples 1 to 3 and comparative examples were evaluated by the following methods. Preparing 150.0g of normal-temperature deionized water, placing the deionized water in a 250mL plastic beaker, and respectively weighing 10.0g of finished product powder prepared in examples 1-3 and comparative example 1; stirring deionized water in a beaker, adjusting the IKA stirring speed to 600rpm/min, carefully pouring finished product powder, timing for 60s, stopping stirring, immediately filtering the solution by using a 40-mesh screen, collecting substances left on the screen, drying at 105 ℃ for 4h, weighing and recording dry solids, wherein the less the dry solids, the better the dissolving effect, detecting each sample for three times, and taking an average value.

TABLE 2 dissolution Effect of instant Soy protein powder

As can be seen from the dissolution effects of the finished products of the comparative example and the examples, the dissolution effects of the soybean protein isolate of the examples are improved to different degrees, and particularly, the soybean protein isolate of the example 3 is dissolved even at normal temperature, and almost no obvious large particles exist within 60s, so that the dissolution is good, and the data also show that the quality of the residual solid particles is the lowest.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.