Plant protein and its preparation method and application

Abstract

The present invention provides a method for preparing plant protein, comprising the following steps: A) enzymolyzing soy milk extract with α-galactosidase, followed by wet heat grafting treatment, and then cooling to obtain heat-treated soy milk cooling liquid; B) enzymolyzing the heat-treated soy milk cooling liquid with protease to obtain enzymolyzed soy milk liquid; C) sterilizing and deactivating the enzymolyzed soy milk liquid and drying it. The present invention uses soybean meal as raw material, uses α-galactosidase to treat the extracted soy milk, and degrades the oligosaccharides therein into monosaccharides and disaccharides; then performs wet heat sugar grafting reaction and protease treatment to reduce the molecular weight of globulin; the production process utilizes the oligosaccharides originally present in the soy milk to carry out glycosylation reaction, while retaining soy whey protein and soy protein hydrolyzate. The present invention prepares a highly emulsified and foaming soy protein product.

Description

Technical Field

[0001] The present invention relates to the field of food technology, in particular to a plant protein and a preparation method and application thereof. Background Art

[0002] Animal-derived sodium caseinate has excellent water solubility, thermal stability, and emulsifying properties, making it widely used in non-dairy creamers, protein drinks, baking, ice cream, and other industries. Foam plays a crucial role in aerated foods and is widely used in food applications such as beer, whipping cream, ice cream, and baking systems, imparting a loose texture and a pleasant mouthfeel. Currently, market demand for plant-based protein is rapidly increasing, driven by the principles of sustainable, environmentally friendly, and nutritious production. However, the emulsifying and foaming properties of plant-based proteins lag significantly behind those of sodium caseinate and egg white protein. Therefore, the development of soy proteins with high emulsifying and foaming properties is of great significance.

[0003] Whey water is produced during the industrial production of soy protein isolate. Every ton of soy protein isolate (SPI) produces approximately 30-40 tons of whey water, of which soy whey protein accounts for approximately 10-15%, sugars for 40-50%, and salt for 20-30%. However, due to its low solids content, whey water is typically disposed of directly in industrial production. This results in the ineffective utilization of soy whey protein, which has excellent emulsifying and foaming properties, and the development of soy oligosaccharides within it is a global challenge. Direct discharge of whey water also causes significant environmental pollution. Therefore, the resource-resourceful and high-value utilization of soy whey water is of paramount importance.

[0004] Conventional methods for improving the emulsification properties of soy protein include glycosylation grafting reaction / protease treatment, or a combination of the two methods. CN114158644A discloses a method for preparing soy protein powder by glycosylation modification. The steps are as follows: adding sugar to the protein solution according to a predetermined protein-sugar mass ratio, stirring thoroughly, and conducting a glycosylation reaction at 60-80°C for 1-4 hours, and obtaining a glycosylated product after the reaction is completed; cooling the glycosylated product to room temperature, purifying, and freeze-drying to obtain a soy protein-sugar complex. The disadvantages of this invention are: the raw materials used are at least one of soy protein isolate, 7S globulin, and 11S globulin, and the production processes of these proteins are very complex, energy-intensive, and highly polluting; the glycosylation grafting reaction time is long, which is not conducive to industrial continuous production.

[0005] CN101959424A discloses a new soy protein material and a preparation method thereof, wherein 30% by weight of sodium caseinate is replaced by soy protein, and the emulsion exhibits high emulsion stability. The steps are as follows: the soy protein material is mixed with a reducing sugar, and then heat-treated at a temperature greater than 100°C to 170°C or less at a pH of 6.3-8.0 for 10-300 seconds, followed by protease hydrolysis to prepare a sugar-containing soy protein material. The disadvantages of this invention are: the raw material is soy protein isolate, the production process is complex, energy-intensive, and a large amount of whey water is discharged, which is detrimental to the environment; and the glycosylation grafting reaction is carried out by the additional addition of reducing sugar, which increases production costs.

[0006] Therefore, it is very necessary to provide a method for preparing plant protein with simple process, low energy consumption and high emulsification and foaming properties. Summary of the Invention

[0007] In view of this, the technical problem to be solved by the present invention is to provide a plant protein, and the plant protein provided by the present invention has both high emulsification and foaming properties.

[0008] The present invention provides a method for preparing plant protein, comprising the following steps:

[0009] A) hydrolyzing the soymilk extract with α-galactosidase, then performing a wet heat grafting treatment, and then cooling to obtain a heat-treated soymilk cooling liquid;

[0010] B) enzymolyzing the heat-treated soymilk cooling liquid with a protease to obtain an enzymolyzed soymilk liquid;

[0011] C) sterilizing and de-enzyming the enzymatically hydrolyzed soybean milk and drying the resulting product.

[0012] Preferably, the amount of α-galactosidase added in step A) is 0.05 wt% to 2 wt%; the pH value of the enzymatic hydrolysis is 6 to 7, the temperature is 45 to 65° C., and the time is 15 to 120 min.

[0013] Preferably, the preparation method of the soymilk extract in step A) is specifically as follows:

[0014] Mixing low-temperature defatted soybean meal with water, adjusting the pH value, stirring and extracting, and separating the solid and liquid to obtain the soymilk extract;

[0015] The mass ratio of the low-temperature defatted soybean meal and water is 1:(6-10); the pH value is 6.0-9.0; the stirring and leaching temperature is 20-60° C., and the time is 30-120 minutes.

[0016] Preferably, the wet heat grafting treatment in step A) is specifically: wet heat treatment at 70°C to 160°C for 4s to 120s; and the cooling is specifically cooling to 40 to 60°C.

[0017] Preferably, the protease in step B) comprises one of alkaline protease, neutral protease or bromelain;

[0018] The added amount of the protease is 0.01% to 0.5wt%; the enzymolysis temperature of the protease is 50-55°C, and the time is 15 to 120 minutes.

[0019] Preferably, the sterilization and enzyme inactivation temperature in step C) is 120-160°C, and the drying is specifically as follows: the air inlet temperature is 150-230°C, and the air outlet temperature is 50-90°C.

[0020] The present invention provides a plant protein, which is prepared by the preparation method described in any one of the above technical solutions.

[0021] The present invention provides the use of plant protein prepared by any one of the preparation methods described above in the preparation of animal protein substitutes.

[0022] The present invention provides a food containing animal protein, the raw materials of which include plant protein and animal protein prepared by the preparation method described in any one of the above technical solutions.

[0023] Preferably, the food comprises non-dairy creamer, cake or ice cream;

[0024] The animal protein includes egg white protein, casein or salts thereof;

[0025] The mass ratio of the plant protein to the animal protein is 15-30:100.

[0026] The present invention also provides a non-dairy creamer, which is prepared by mixing, sterilizing, homogenizing and spray-drying the vegetable protein, sodium caseinate, glucose syrup and palm oil prepared by the preparation method described in any one of the above technical solutions.

[0027] The present invention also provides a cake, the raw materials of which include the plant protein prepared by the preparation method described in any one of the above technical solutions.

[0028] Compared to the prior art, the present invention provides a method for preparing plant protein, comprising the following steps: A) enzymatically hydrolyzing a soymilk extract with α-galactosidase, followed by a wet-heat grafting reaction, and then cooling to obtain a heat-treated soymilk cooling liquid; B) enzymatically hydrolyzing the heat-treated soymilk cooling liquid with a protease to obtain an enzymatically hydrolyzed soymilk liquid; and C) sterilizing and deactivating the enzymatically hydrolyzed soymilk liquid and drying it. The present invention uses soybean meal as a raw material, treats the extracted soymilk with α-galactosidase, and degrades the oligosaccharides therein into monosaccharides and disaccharides. Subsequently, a wet-heat sugar grafting reaction and protease treatment are performed to reduce the molecular weight of the globulin. This production process utilizes the oligosaccharides already present in the soymilk for glycosylation, while retaining soy whey protein and soy protein hydrolysate. The present invention produces a highly emulsifying and foaming soy protein product. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The emulsions of Examples 1-3 and Comparative Example 1 were left standing for 10 minutes;

[0030] Figure 2 The HPLC molecular weight distribution results of Example 2-a / d / e are as follows;

[0031] Figure 3 The foaming test results of Examples 2-a to e are as follows;

[0032] Figure 4 The whipping effect of whole egg white, 15% and 30% egg white substitute;

[0033] Figure 5 The states of chiffon cake made with whole egg white, 15% and 30% egg white substitute. DETAILED DESCRIPTION

[0034] The present invention provides a plant protein composition and a method for preparing the same. Those skilled in the art can refer to the contents of this article and appropriately improve the process parameters to achieve the same. It should be noted that all similar replacements and modifications are obvious to those skilled in the art and fall within the scope of protection of the present invention. The methods and applications of the present invention have been described through preferred embodiments. Relevant personnel can obviously modify or appropriately change and combine the methods and applications herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0035] In this application, the term "and / or" describes the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0036] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items.

[0037] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0038] The present invention provides a method for preparing plant protein, comprising the following steps:

[0039] A) hydrolyzing the soymilk extract with α-galactosidase, then performing a wet heat grafting treatment, and then cooling to obtain a heat-treated soymilk cooling liquid;

[0040] B) enzymolyzing the heat-treated soymilk cooling liquid with a protease to obtain an enzymolyzed soymilk liquid;

[0041] C) sterilizing and de-enzyming the enzymatically hydrolyzed soybean milk and drying the resulting product.

[0042] The method for preparing plant protein provided by the present invention first prepares soy milk extract.

[0043] In some preferred embodiments of the present invention, the preparation method of the soymilk extract is specifically as follows:

[0044] The low-temperature defatted soybean meal is mixed with water, the pH value is adjusted, the mixture is stirred and extracted, and the solid-liquid is separated to obtain the soybean milk extract.

[0045] The present invention first mixes low-temperature defatted soybean meal and water; the mass ratio of the low-temperature defatted soybean meal and water is 1: (6-10);

[0046] In some embodiments, the low-temperature defatted soybean meal and water are mixed in a mass ratio of 1:7, 1:8, 1:9 or 1:10.

[0047] The pH value is 6.0-9.0; sodium hydroxide is preferably used to adjust the pH value in the present invention.

[0048] Specifically, the stirring and leaching temperature is 20-60° C., and the time is 30-120 minutes.

[0049] In some embodiments, the stirring and leaching is carried out at a temperature of 30 to 58° C. and for a time of 35 to 100 minutes.

[0050] In some embodiments, the stirring and leaching is carried out at a temperature of 50 to 55° C. and for a time of 40 to 80 minutes.

[0051] The raw materials of the low-temperature defatted soybean meal of the present invention include soybeans, peas, mung beans, red beans and black beans.

[0052] After the extraction is completed, solid-liquid separation is performed to remove the dregs component to obtain the soymilk extract.

[0053] The prepared soymilk extract was enzymatically hydrolyzed with α-galactosidase.

[0054] The addition amount of the α-galactosidase of the present invention is preferably 0.05wt% to 2wt%; more preferably 0.05wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%; or any value between the above two.

[0055] According to the present invention, the pH value of the enzymatic hydrolysis is 6 to 7, and hydrochloric acid is preferably used to adjust the pH value.

[0056] Specifically, the enzymatic hydrolysis temperature is 45 to 65° C., and the time is 15 to 120 minutes.

[0057] In some preferred embodiments, the enzymatic hydrolysis temperature is 50-60° C., and the time is 20-100 min.

[0058] After enzymatic hydrolysis, the product is subjected to a wet heat grafting treatment and then cooled to obtain a heat-treated soymilk cooling liquid.

[0059] The wet heat grafting treatment of the present invention is specifically: wet heat treatment at 70°C to 160°C for 4s to 120s;

[0060] In some preferred embodiments, the wet heat grafting treatment is specifically: wet heat treatment at 80° C. to 150° C. for 8s to 100s;

[0061] In some preferred embodiments, the wet heat grafting treatment is specifically: wet heat treatment at 90° C. to 140° C. for 8 seconds to 90 seconds;

[0062] The cooling is specifically cooling to 40-60°C.

[0063] The heat-treated soymilk cooling liquid is enzymatically hydrolyzed with protease to obtain enzymatically hydrolyzed soymilk liquid.

[0064] The protease of the present invention includes one of alkaline protease, neutral protease or bromelain;

[0065] Specifically, the added amount of the protease is 0.01wt% to 0.5wt%;

[0066] In some preferred embodiments, the added amount of the protease is 0.05 wt% to 0.5 wt%;

[0067] In some preferred embodiments, the added amount of the protease is 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.5 wt%; or any value between the above two.

[0068] The enzymatic hydrolysis temperature of the protease of the present invention is 50-55° C., and the enzymatic hydrolysis time is 15-120 minutes.

[0069] In some embodiments, the enzymatic hydrolysis temperature of the protease is 50-55° C., and the time is 20 to 100 minutes.

[0070] The enzymatically hydrolyzed soymilk is sterilized, enzyme-killed and dried to obtain the product.

[0071] The sterilization and enzyme inactivation temperature of the present invention is 120-160° C. and the time is 8-120 seconds.

[0072] The drying method of the present invention is spray drying.

[0073] The drying method of the present invention is specifically as follows: the air inlet temperature is 150-230°C, and the air outlet temperature is 50-90°C.

[0074] In some embodiments, the drying is specifically as follows: the air inlet temperature is 160-220°C, and the air outlet temperature is 55-85°C.

[0075] The present invention provides a plant protein, which is prepared by the preparation method described in any one of the above technical solutions.

[0076] The invention degrades oligosaccharides in soybean milk extract into monosaccharide and disaccharide components, performs glycosylation grafting through wet heat treatment, and then performs protease hydrolysis, sterilization, enzyme inactivation and spray drying to obtain highly emulsified and foaming soybean protein.

[0077] The present invention provides the use of plant protein prepared by any one of the preparation methods described above in the preparation of animal protein substitutes.

[0078] The present invention provides a food containing animal protein, the raw materials of which include plant protein and animal protein prepared by the preparation method described in any one of the above technical solutions.

[0079] The food of the present invention includes non-dairy creamer, cake or ice cream;

[0080] The animal protein includes egg white protein, casein or salts thereof; that is, it can be whey protein, casein, or sodium caseinate.

[0081] The mass ratio of the plant protein to the animal protein is 15-30:100.

[0082] The present invention also provides a non-dairy creamer, which is prepared by mixing, sterilizing, homogenizing and spray-drying the vegetable protein, sodium caseinate, glucose syrup and palm oil prepared by the preparation method described in any one of the above technical solutions.

[0083] In a specific embodiment of the present invention:

[0084] The non-dairy creamer is prepared according to the following formula: sodium caseinate and the plant protein sample prepared by the present invention are fully stirred and dissolved in proportion at 65-70° C., glucose syrup is added to prepare an aqueous phase, and the mixture is homogenized at 2000 r for 5 minutes; oil is heated to 70-75° C., the oil phase in a stirred state is added to the aqueous phase at a relatively slow speed, and stirred at 2500 r for 20 minutes; after pasteurization, the mixture is homogenized once at 30 mPa; and spray drying is performed to obtain the non-dairy creamer product.

[0085] The experiment shows that samples with different replacement ratios all show good oil embedding rate; in terms of taste, samples with a replacement ratio of 30% have different tastes, and samples with a replacement ratio of 40% have unpleasant flavors, with prominent bitterness and beany smell.

[0086] Therefore, the preferred proportion of the present invention in replacing sodium caseinate to prepare non-dairy creamer is 15% to 30%.

[0087] The present invention does not limit the specific preparation method of the non-dairy creamer, which is well known to those skilled in the art.

[0088] The present invention also provides a cake, the raw materials of which include the plant protein prepared by the preparation method described in any one of the above technical solutions.

[0089] In a specific embodiment of the present invention, the cake is prepared according to the following method:

[0090] After the vegetable protein prepared by the present invention is dissolved, it is mixed with egg white in a proportion and beaten. During the beating process, white sugar is added three times and the mixture is beaten until a small inverted triangle is formed. Liquid shortening, corn starch and low-gluten flour are evenly mixed, and then egg yolks are added and stirred evenly. The beaten liquid is added to the egg yolk paste, the mixture is mixed, and the mixture is poured into a mold. The cake is baked at 160° C. on the upper fire and 140° C. on the lower fire for 40 minutes, and the cake is cooled and taken out of the mold to obtain the cake.

[0091] The experimental results show that the specific volume and egg white whipping performance of the cake made with a replacement ratio of 15% have no significant difference compared with the whole egg liquid cake, and the taste and texture state have not changed; when the replacement ratio is 30%, the egg white whipping performance first deteriorates, the foam elasticity after whipping deteriorates, and the cake rebounds slowly when pressed after baking.

[0092] Therefore, the preferred proportion of the egg white protein used in preparing cakes according to the present invention is 15%.

[0093] The present invention uses soybean meal as raw material, uses α-galactosidase to treat the extracted soy milk, and degrades the oligosaccharides therein into monosaccharides and disaccharides; then performs a moist heat sugar grafting reaction and a protease treatment to reduce the molecular weight of the globulin; the production process utilizes the oligosaccharides originally present in the soy milk to carry out a glycosylation reaction, while retaining soy whey protein and soy protein hydrolysate; and turns whey water into treasure, which is suitable for industrial production.

[0094] The present invention provides a soy protein material, which has good emulsification and foaming properties, can partially or completely replace sodium caseinate and egg white protein, and is used in ice cream, non-dairy creamer, and baked products.

[0095] To further illustrate the present invention, the plant protein provided by the present invention, its preparation method and application are described in detail below with reference to the examples.

[0096] The present invention preferably uses the following method to detect the products of the embodiments and comparative examples:

[0097] (1) Soybean protein determination

[0098] The content of highly emulsifying and foaming soy protein was determined with reference to GB5009.5-201 "Determination of Protein in Foods". The results were calculated on a dry basis, and the conversion coefficient of soy protein was 6.25.

[0099] (2) Determination of hydrolysis degree

[0100] Prepare 0.22 mol / L trichloroacetic acid solution, dissolve the sample, centrifuge and determine the nitrogen content of the supernatant.

[0101] (3) Emulsification determination

[0102] Weigh 0.5g of protein powder and dissolve it in 100mL of pH=7.0 phosphate buffer solution. After stirring evenly, add 33mL of soybean oil to make the oil phase volume fraction (ρ) be 0.25. After homogenizing with a high-speed shearing machine at 10000r / min for 1min, quickly draw 50uL of emulsion from the bottom and add it to 10mL of prepared 1% SDS (w / v) solution, and the dilution factor is 200. After slightly shaking the test liquid, transfer it to a cuvette with a light path of 1cm, and measure the absorbance at 500nm, which is recorded as A0. After the emulsion is allowed to stand at room temperature for 10min (t), draw 50uL from the bottom again and add it to 10mL of prepared 1% SDS solution. After slightly shaking, transfer it to a cuvette, and measure the absorbance at 500nm again, which is recorded as A 30 .

[0103]

[0104]

[0105] (4) Foaming property measurement

[0106] Weigh 1g of protein powder and dissolve it in 100mL of pH 7.0 phosphate buffer solution. The initial solution volume is 100, recorded as V0 (mL). Use an IKA stirrer at 800rpm for 10min to evenly disperse the protein solution. Homogenize the solution with a high-speed shear at 10,000rpm for 90s, then quickly pour the solution into a 250ml graduated cylinder and record the total volume of the liquid and foam (V1 (mL). Let the glass cylinder rest for 30min and record the total volume (V2 (mL).

[0107]

[0108]

[0109] (5) High performance gel liquid chromatography (HPLC) analysis

[0110] A Waters high performance gel liquid chromatography (HPLC) system was used for the operation. The mobile phase was 0.01 mol / L phosphate buffer solution pH 6.7 (containing 0.1 mol / L Na2SO4 + 0.05% NaN3), the column temperature was room temperature (25°C), the flow rate was 0.5 mL / min, the injection volume was 20 μL, and the detection wavelength was 210 nm. The sample was fully hydrated and dissolved, filtered using a 0.45 μm filter membrane, and the gel column was equilibrated with the mobile phase before injection. The standards used were thyroglobulin (MW 640000), ferritin (500000), ovalbumin (MW 47000), and p-aminobenzoic acid (137). The test results were calculated using the area normalization method to calculate the molecular weight distribution of the hydrolyzate.

[0111] (6) Cake food analysis

[0112] (a) Cake sensory evaluation

[0113] A five-person sensory panel evaluated the taste, texture, and texture of the cakes. The taste was graded into three levels: rough, slightly dense, and very dense, marked as "-," "--," and "---." The texture of the baked cakes was also graded into three levels: poor elasticity, slightly elasticity, and good elasticity, marked as "△," "△△," and "△△△," respectively.

[0114] (b) Cake specific volume: Cake specific volume = volume of cake / mass of cake

[0115] (c) Center height: Cut the cake lengthwise down the middle. The height difference between the highest and lowest points on the cross section is the center height of the cake.

[0116] (d) Cake texture measurement: A 5 cm × 5 cm slice was taken from the center of the cake and analyzed using a physical property analyzer. The measurement parameters were set as follows: pre-test speed 1 mm / s, test speed 1 mm / s, post-test speed 10 mm / s, compression degree 25%, and an interval of 30 s between two compressions.

[0117] (7) Evaluation of non-dairy creamer

[0118] (a-1) Determination of oil embedding rate of non-dairy creamer:

[0119] Weigh 3 g (M) of non-dairy creamer sample and 40 mL of petroleum ether in a conical flask and shake gently for 1 min. Filter the mixture and inject it into a constant weight drying conical flask (M1). Place the mixture in an 80°C water bath to evaporate the petroleum ether, and then dry M1 in a 105°C oven to constant weight (M2).

[0120]

[0121] (a-2) Determination of total fat content of non-dairy creamer (acid hydrolysis method):

[0122] Weigh 2.000g of sample into a stoppered graduated cylinder, add 8mL of distilled water, shake well, add 10mL of hydrochloric acid, and place in an 80°C water bath, shaking every 10 minutes. Remove after 1 hour. Add 10mL of ethanol to the test tube, mix thoroughly, and cool. Add 40mL of petroleum ether. Once the mixture is clear, aspirate the supernatant and inject it into a constant-weight conical flask (m0). Repeat the extraction by adding 10mL of petroleum ether. Aspirate the supernatant and inject it into m0. Repeat twice. Place m0 in an 80°C water bath to dryness, then place in a 105°C oven. Dry for 2 hours before removing and weighing (m1).

[0123]

[0124]

[0125] (b) Sensory evaluation of non-dairy creamer:

[0126] A five-person sensory panel evaluated the taste and flavor of the rice. The taste was categorized into three levels: bland, slightly full-bodied, and relatively full-bodied, marked as "*," "**," and "***," respectively. The flavor was categorized into three levels: no bitterness and no beany, bitterness without a beany flavor, and bitterness with a beany flavor, marked as "√√," "√," and "×," respectively.

[0127] Comparative Example 1

[0128] 3 kg of low-temperature defatted soybean meal was weighed, 21 kg of deionized water was added, and the mixture was heated to 50-55° C., and then the pH was adjusted to 7.5 using a NaOH solution. The mixture was extracted with constant temperature stirring for 40 minutes, and the mixture was centrifuged at 4000 r / min for 5 minutes to separate and remove insoluble soybean dregs fiber to obtain 20 kg of soy milk extract; the pH of the hydrolyzate was adjusted to 6.0-7.0 using an HCl solution, and 0.05%, 0.5%, or 1% α-galactosidase was added to the soy milk solid content for 60 minutes (respectively, 1-a, 1-b, or 1-c); a sterilization flash heat treatment was performed at 140° C. for 60 seconds, and then spray drying was performed at an inlet air temperature of 175° C. and an outlet air temperature of 75° C. to obtain a highly emulsified and foaming product.

[0129] Comparative Example 2

[0130] Weigh 3 kg of low-temperature defatted soybean meal, add 21 kg of deionized water, heat to 50-55 ° C, adjust the pH to 7.5 with NaOH solution, extract with constant temperature stirring for 40 minutes, centrifuge the mixture at 4000 r / min for 5 minutes to separate and remove insoluble soybean dregs fiber, and obtain 20 kg of soy milk extract, which is heat treated at 140 ° C for 60 seconds; spray drying is carried out at an inlet air temperature of 175 ° C and an outlet air temperature of 75 ° C to obtain a highly emulsified and foaming product.

[0131]

[0132] The emulsification of the sample treated in Comparative Example 1-c was significantly improved compared to the sample in Comparative Example 2 (blank control); Comparative Example 1 only treated with α-galactosidase to convert oligosaccharides into monosaccharides, disaccharides, etc., and a glycosylation grafting reaction occurred, which significantly improved the emulsification. Figure 1 It can be seen that the emulsion of comparative example 1-c is relatively stable and stratification occurs only after standing for 30 minutes.

[0133] Example 1

[0134] 3 kg of low-temperature defatted soybean meal is weighed, 21 kg of deionized water is added, and the mixture is heated to 50-55° C., and then the pH is adjusted to 7.5 using a NaOH solution. The mixture is extracted with constant temperature stirring for 40 minutes, and the mixture is centrifuged at 4000 r / min for 5 minutes to separate and remove insoluble soybean dregs fiber to obtain 20 kg of soy milk extract; the pH of the hydrolyzate is adjusted to 6.0-7.0 using an HCl solution, and α-galactosidase with a soy milk solid content of 1% is added and treated for 60 minutes; the mixture is heat treated at 140° C. for 60 seconds, the heat-treated soy milk is cooled to 50-55° C., and alkaline protease with a soy milk solid content of 0.3% is added and treated for 30 minutes; the mixture is sterilized by flash heat treatment at 140° C. for 60 seconds, and then spray-dried at an inlet air temperature of 175° C. and an outlet air temperature of 75° C. to obtain a highly emulsified and foaming product.

[0135] Example 2

[0136] 3 kg of low-temperature defatted soybean meal is weighed, 21 kg of deionized water is added, and the mixture is heated to 50-55° C., and then the pH is adjusted to 7.5 using a NaOH solution. The mixture is extracted with constant temperature stirring for 40 minutes, and the mixture is centrifuged at 4000 r / min for 5 minutes to separate and remove insoluble soybean dregs fiber to obtain 20 kg of soy milk extract; the pH of the hydrolyzate is adjusted to 6.0-7.0 using an HCl solution, and α-galactosidase with a soy milk solid content of 1% is added and treated for 60 minutes; a heat treatment is performed at 140° C. for 60 seconds, the heat-treated soy milk is cooled to 50-55° C., and alkaline protease with a soy milk solid content of 0.3% is added and treated for 30 minutes; a sterilization flash heat treatment is performed at 120° C. for 15 minutes, and then spray drying is performed with an inlet air temperature of 175° C. and an outlet air temperature of 75° C. to obtain a highly emulsified and foaming product.

[0137] Example 3

[0138] 3 kg of low-temperature defatted soybean meal is weighed, 21 kg of deionized water is added, and the mixture is heated to 50-55° C., and then the pH is adjusted to 7.5 using a NaOH solution. The mixture is extracted with constant temperature stirring for 40 minutes, and the mixture is centrifuged at 4000 r / min for 5 minutes to separate and remove insoluble soybean dregs fiber to obtain 20 kg of soy milk extract; the pH of the hydrolyzate is adjusted to 6.0-7.0 using an HCl solution, and α-galactosidase with a soy milk solid content of 1% is added and treated for 60 minutes; a heat treatment is performed at 140° C. for 60 seconds, the heat-treated soy milk is cooled to 50-55° C., and alkaline protease with a soy milk solid content of 0.3% is added and treated for 30 minutes; a sterilization flash heat treatment is performed at 90° C. for 30 minutes, and then spray drying is performed at an inlet air temperature of 175° C. and an outlet air temperature of 75° C. to obtain a highly emulsified and foaming product.

[0139]

[0140] In Example 1, the sample treated at 140°C for 60 seconds exhibited good emulsification and emulsion stability. High-temperature treatment after α-galactosidase facilitated the glycosylation grafting reaction, thereby improving emulsification and emulsion stability. Similarly, short-term heat treatment increased proteolysis efficiency, improving both foaming and foaming stability. Glycosylation combined with protease treatment exhibited a synergistic effect, resulting in superior emulsification and foaming properties compared to samples treated under either treatment condition.

[0141] Comparative Example 3

[0142] 3 kg of low-temperature defatted soybean meal was weighed, 21 kg of deionized water was added, and the mixture was heated to 50-55 ° C., and then the pH was adjusted to 7.5 with a NaOH solution. The mixture was extracted with constant temperature stirring for 40 minutes, and the mixture was centrifuged at 4000 r / min for 5 minutes to separate and remove insoluble soybean dregs fiber to obtain 20 kg of soy milk extract; a heat treatment was performed at 140 ° C. for 60 seconds, and the heat-treated soy milk was cooled to 50-55 ° C., and alkaline protease with a soy milk solid content of 0.05%, 0.1%, 0.2%, 0.3%, and 0.5% was added and treated for 30 minutes (Comparative Example 3-a, Comparative Example 3-b, Comparative Example 3-c, Comparative Example 3-d, and Comparative Example 3-e, respectively); a sterilization flash heat treatment was performed at 140 ° C. for 8 seconds, and then spray-dried with an inlet air temperature of 175 ° C. and an outlet air temperature of 75 ° C. to obtain a highly emulsified and foaming product.

[0143] Comparative Example 4

[0144] 3 kg of low-temperature defatted soybean meal was weighed, 21 kg of deionized water was added, and the mixture was heated to 50° C.-55° C., and then the pH was adjusted to 7.5 with a NaOH solution. The mixture was extracted with constant temperature stirring for 40 minutes, and the mixture was centrifuged at 4000 r / min for 5 minutes to separate and remove insoluble soybean dregs fiber to obtain 20 kg of soy milk extract; the pH was adjusted to 9.0, and then a heat treatment was performed at 140° C. for 8 seconds. The heat-treated soy milk was cooled to 50° C.-55° C., divided into three parts, and treated with a neutral protease with a soy milk solid content of 2‰ for 30 minutes; the pH of the hydrolyzate was adjusted to 4.5 with an HCl solution, and the mixture was centrifuged at 4000 r / min for 5 minutes to separate and remove insoluble matter; the filtrate was subjected to a sterilization flash heat treatment at 140° C. for 8 seconds, and then concentrated to 30% of the solid content at a vacuum degree of -0.08 MPa; and the mixture was spray-dried with an inlet air temperature of 175° C. and an outlet air temperature of 75° C. to obtain a soy protein foaming composite product.

[0145]

[0146]

[0147] Comparative Examples 3-a to e: With the increase of hydrolysis degree, the emulsification and emulsion stability show a trend of first increasing and then decreasing, the foaming property is enhanced, but the stability is significantly reduced; the content of insoluble aggregates is reduced, and the low molecular weight fragments are increased.

[0148] Combine Figure 2 、 3Analysis of the HPLC molecular weight determination results shows that the sample treated with Comparative Example 3-a contains a large number of insoluble aggregates with a molecular weight of approximately 520 kDa. The sample treated with Comparative Example 3-d has a molecular weight range of approximately 20-70 kDa. This range facilitates rapid protein adsorption to the oil-water interface and forms a stable interfacial structure. The sample treated with Comparative Example 3-e has a molecular weight range of approximately 7-20 kDa. Low molecular weight fragments are more conducive to improved foaming properties, but the foam stability is deteriorated. Overall, a hydrolysis degree of around 30% is selected to achieve a good balance between emulsification, emulsion stability, foaming properties, and foam stability.

[0149] Although Comparative Example 4 exhibited certain advantages in foaming properties and foam stability, the centrifugation process during the preparation of Comparative Example 4 removed some insoluble matter, resulting in a sample hydrolysis degree close to 100%, indicating that the main components were polypeptide fragments. This solution also had disadvantages, including a low product yield and high production costs, which limited its competitive advantage.

[0150] Application Case 1

[0151] A highly emulsified and foaming product was prepared in the same manner as in Example 1. The cake making method was as follows: the highly emulsified and foaming product was prepared into a 15% solution, and the materials were added according to the data in the table below. White sugar was added three times during the beating of the egg whites, and the mixture was beaten until a small inverted triangle was formed. Liquid shortening, corn starch, and low-gluten flour were evenly mixed, and then the egg yolks were added and stirred evenly. The beaten liquid was added to the egg yolk paste, mixed well, and poured into a mold. The mixture was baked at 160° C. on the upper heat and 140° C. on the lower heat for 40 minutes, and the cake was cooled and removed from the mold to obtain the cake.

[0152]

[0153] The cake taste, tissue state and texture indexes are determined as follows:

[0154]

[0155]

[0156] From the data of application case 1 and combined Figure 4 、 5 As can be seen from the example, the specific volume and egg white whipping performance of the cake made with a replacement ratio of 15% have no obvious difference compared with the whole egg liquid cake, and the taste and texture state have not changed; when the replacement ratio is 30%, the first manifestation is that the egg white whipping performance deteriorates, the foam elasticity deteriorates after whipping, and the cake rebounds slowly when pressed after baking.

[0157] Application Case 2

[0158] A highly emulsified and foaming product was prepared in the same manner as in Example 1. The non-dairy creamer was prepared according to the following formula: sodium caseinate and a plant protein substitute were stirred and dissolved in proportion at 65-70°C, glucose syrup was added to prepare an aqueous phase, and homogenized at 2000r for 5 min; the oil was heated to 70-75°C, and the stirred oil phase was added to the aqueous phase at a relatively slow speed, and stirred at 2500r for 20 min; after pasteurization, the mixture was homogenized once at 30mPa; and the non-dairy creamer product was obtained by spray drying.

[0159]

[0160] The taste and embedding efficiency of non-dairy creamer are determined as follows:

[0161]

[0162] In Application Case 2, samples with different replacement ratios all showed good oil embedding rates; in terms of taste, samples with a replacement ratio of 30% had different tastes, and samples with a replacement ratio of 40% had unpleasant flavors, with prominent bitterness and beany smells.

[0163] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing plant protein, characterized in that: The steps include: A) The soymilk extract is enzymatically hydrolyzed with α-galactosidase, and then subjected to a wet heat grafting treatment, and then cooled to obtain a heat-treated soymilk cooling liquid; the preparation method of the soymilk extract is specifically as follows: Mixing low-temperature defatted soybean meal with water, adjusting the pH value, stirring and extracting, and separating the solid and liquid to obtain the soymilk extract; The wet heat grafting treatment is specifically: wet heat treatment at 70°C to 160°C for 4s to 120s; B) enzymatically hydrolyzing the heat-treated soymilk cooling liquid with a protease to obtain an enzymatically hydrolyzed soymilk liquid; C) The enzymatically hydrolyzed soymilk is sterilized and enzyme-inactivated, and dried to obtain the product.

2. The preparation method according to claim 1, characterized in that In step A), the amount of α-galactosidase added is 0.05 wt % to 2 wt %; the pH value of the enzymatic hydrolysis is 6 to 7, the temperature is 45 to 65° C., and the time is 15 to 120 min.

3. The preparation method according to claim 1, characterized in that Step A) The mass ratio of the low-temperature defatted soybean meal and water is 1:(6-10); the pH value is 6.0-9.0; the stirring and leaching temperature is 20-60° C., and the time is 30-120 minutes.

4. The preparation method according to claim 1, characterized in that The cooling step A) is specifically cooling to 40-60°C.

5. The preparation method according to claim 1, characterized in that Step B) the protease comprises one of alkaline protease, neutral protease or bromelain; The added amount of the protease is 0.01% to 0.5wt%; the enzymolysis temperature of the protease is 50-55°C, and the time is 15 to 120 minutes.

6. The preparation method according to claim 1, characterized in that Step C) The sterilization and enzyme inactivation temperature is 120-160°C, and the drying is specifically as follows: the inlet air temperature is 150-230°C, and the outlet air temperature is 50-90°C.

7. A plant protein, characterized in that The preparation method is described in any one of claims 1 to 6.

8. Use of the plant protein prepared by the preparation method according to any one of claims 1 to 6 in the preparation of animal protein substitutes.

9. A food containing animal protein, characterized in that: The raw materials include plant protein and animal protein prepared by the preparation method according to any one of claims 1 to 6.

10. The food according to claim 9, characterized in that The food includes non-dairy creamer, cake or ice cream; The animal protein includes egg white protein, casein or salts thereof; The mass ratio of the plant protein to the animal protein is 15-30:100.

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