A method for preparing modified alcohol method soy protein concentrate suitable for plant-based dairy preparation and applications

Abstract

The application discloses a preparation method and application of modified alcohol method soybean protein concentrate suitable for plant-based milk preparation and belongs to the field of food processing. In view of the problems of poor stability of existing alcohol method soybean protein concentrate (SPC) in preparing plant-based milk and difficulty in application in whipped cream / cooking milk products, the SPC is prepared into a protein solution and hydrated, 500 W ultrasonic pretreatment is carried out for 8 min, then pH is adjusted, papain (E / S=1:50, 50 DEG C, pH 6.0, 60 min) is added for enzymolysis and enzyme inactivation, pre-emulsion is obtained by high-speed shearing with sunflower oil (4:1 v / v), 0.05%-0.3% tri-sodium citrate is added and mixed and sheared, pasteurization and cooling are carried out, and a weak gel network is formed. The plant-based milk prepared by the application has the advantages of no delamination and no oil separation after 30-day storage at 25 DEG C, heat resistance, rheological characteristics close to whipped cream and the like, and chemical reagent use is reduced to the maximum, the process is green and simple, and the alcohol method SPC can be extended to the field of plant-based whipped cream / cooking milk.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a method for preparing modified alcohol-based soy protein concentrate, and the application of the modified alcohol-based soy protein concentrate prepared by this method in plant-based milk, particularly in plant-based cream and cooking milk. Background Technology

[0002] Alcohol-washed soy protein concentrate (SPC) is a protein product made from low-temperature defatted soybean meal through edible-grade ethanol extraction to remove soluble sugars, ash, and some flavor substances. Its protein content is typically no less than 65%. Compared to acid washing processes, the alcohol-washing process produces no large amounts of acid or alkali wastewater, making it more environmentally friendly. Furthermore, the product has low levels of anti-nutritional factors, thus holding significant application potential in the plant-based food sector. However, during ethanol treatment, proteins undergo severe denaturation and aggregation, exposing numerous hydrophobic groups within the molecules and disrupting the original natural globular structure, forming dense protein aggregates. This results in significant limitations in the processing applicability of alcohol-washed soy protein concentrate, primarily manifested in low solubility and poor dispersibility in water. Consequently, its emulsifying, foaming, and gelling properties are severely compromised, making it difficult to directly apply to liquid or semi-solid plant-based dairy products requiring high stability, such as plant-based whipped cream and cooking milk.

[0003] To improve the functional properties of alcohol-processed soy protein concentrate, various physical, chemical, and enzymatic modification methods have been explored in existing technologies. In terms of physical modification, ultrasonic treatment can disrupt protein aggregates and improve dispersibility and solubility due to its cavitation effect. However, ultrasonic treatment alone has limited effect on improving emulsifying activity, and excessive ultrasonication can easily lead to the re-aggregation of hydrophobic protein groups, forming insoluble aggregates. In terms of enzymatic modification, restrictive hydrolysis using proteases (such as alkaline proteases, neutral proteases, papain, etc.) can expose hydrophilic / hydrophobic groups and improve surface activity. However, enzymatic hydrolysis alone is difficult to effectively open dense alcohol-denatured protein aggregates, resulting in insufficient exposure of enzyme cleavage sites, leading to low hydrolysis efficiency or easy over-hydrolysis, which can impair functional properties. Some studies have also attempted to combine ultrasonication with enzymatic hydrolysis, for example, performing them simultaneously or enzymatic hydrolysis followed by ultrasonication. However, existing technologies lack systematic control strategies for the order and parameter matching of the two treatment methods (such as ultrasonic power and time, enzymatic hydrolysis temperature, pH, enzyme dosage, and time), often failing to fully realize the synergistic effect.

[0004] Furthermore, in preparing plant-based milk systems based on alcohol-based soy protein concentrate, the addition of hydrophilic colloids (such as xanthan gum, guar gum, carrageenan, and triazine) is a common practice to achieve rheological properties and long-term shelf stability similar to commercially available cream. However, the selection and addition amount of polysaccharides in existing technologies largely rely on trial and error, lacking adaptive guidance strategies specific to the aggregate structure of alcohol-modified proteins. The interaction mechanisms between different polysaccharides and modified proteins vary significantly: while some polysaccharides can thicken, higher addition amounts (usually >0.5%) are required to maintain system stability, and high concentrations of polysaccharides can easily lead to a sticky texture and poor flavor release; if the addition amount is too low, it is difficult to form a weak gel network sufficient to resist gravity-induced phase separation, and the emulsion is prone to stratification and oil separation during storage. In addition, using high-intensity homogenization or ultra-high temperature sterilization processes to assist stabilization may further exacerbate protein aggregation and increase equipment costs and energy consumption.

[0005] Currently, there is a lack of clear technical guidance on how to precisely screen for synergistically matched polysaccharide types and extremely low addition ranges based on the specific modified state of alcohol-processed soy protein concentrate, in order to simultaneously achieve long-term storage stability and cream-like rheological properties without the need for high-intensity sterilization. Therefore, a modification method that can significantly improve the solubility, foaming properties, emulsifying activity, and emulsifying stability of alcohol-processed soy protein concentrate, and can prepare plant-based milk with excellent storage stability and suitable rheological properties under low polysaccharide dosage and mild sterilization conditions, is of great significance for expanding the application range of alcohol-processed soy protein concentrate in plant-based cream, cooking milk, and other products. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing alcohol-based soy protein concentrate preparation methods in plant-based milk preparation, such as low solubility, poor dispersibility, insufficient emulsifying and foaming properties, resulting in poor emulsion stability and easy oil separation. Furthermore, existing modification methods lack clear understanding of the sequence and key parameters of ultrasonic and enzymatic hydrolysis treatment, such as power, time, temperature, pH, and enzyme addition amount; lack systematic guidance on protein-polysaccharide complex regulation strategies; and require the addition of large amounts of hydrophilic colloids or the use of high-intensity sterilization processes. This invention provides a modified alcohol-based soy protein concentrate preparation method and its application suitable for plant-based milk preparation.

[0007] To achieve the above objectives, the present invention provides a method for preparing modified alcohol-based soy protein concentrate suitable for plant-based milk preparation, comprising the following steps:

[0008] S1. Using alcohol-based soy protein concentrate as raw material, prepare a protein solution and hydrate it by stirring;

[0009] S2. The solution is pretreated with ultrasound, and then the pH value is adjusted;

[0010] S3. Add papain for enzymatic hydrolysis, then inactivate the enzyme;

[0011] S4. The enzymatically hydrolyzed solution is mixed with vegetable oil and sheared at high speed to obtain a pre-emulsion;

[0012] S5. Add triazine gum to the pre-emulsion, mix and shear, then pasteurize and cool to obtain plant-based emulsion.

[0013] Preferably, the protein solution concentration in step S1 is 2%~6% (w / w), the stirring speed is 200~600 rpm, the stirring time is 1~3 h, and the hydration condition is overnight at 4°C.

[0014] More preferably, the concentration of the protein solution in step S1 is 4% (w / w).

[0015] Preferably, the ultrasonic pretreatment power in step S2 is 100~700 W, and the time is 0~20 min.

[0016] More preferably, the ultrasonic pretreatment power in step S2 is 500 W and the time is 8 min.

[0017] Preferably, the papain hydrolysis conditions in step S3 are as follows: the amount of enzyme added is 0.5% to 5% of the protein content of the alcohol-based soybean concentrate (E / S = 1:200 to 1:20), the hydrolysis temperature is 50 to 60°C, the pH is 5.0 to 7.0, and the hydrolysis time is 15 to 240 min; the enzyme inactivation conditions are a water bath at 85 to 95°C for 5 to 15 min.

[0018] More preferably, the papain hydrolysis conditions in step S3 are: E / S = 1:50, temperature 50°C, pH 6.0, and time 60 min.

[0019] Preferably, the vegetable oil in step S4 is sunflower seed oil, and the volume ratio of sunflower seed oil to protein solution is 3:1 to 5:1, the shearing speed is 8000 to 12000 rpm, and the time is 1 to 3 min.

[0020] More preferably, the volume ratio of sunflower seed oil to protein solution in step S4 is 4:1.

[0021] Preferably, in step S5, the mass concentration of the triazine in the final emulsion is 0.01%~0.7% (w / w), the homogenization speed is 8000~12000 rpm, and the time is 2~5 min; the pasteurization conditions are 80~90℃ for 20~40 min, and then cooled to 0~10℃.

[0022] More preferably, the mass concentration of the triacin in the final emulsion in step S5 is 0.05%~0.3% (w / w).

[0023] Preferably, the composition of the alcohol-based soybean protein concentrate raw material by weight percentage is: 65%~71% protein, 0.19% fat, ≤2.71% fiber, 5.8%~7.0% ash, 5.5%~7.5% moisture, and about 20.8% carbohydrates.

[0024] Preferably, the alcohol-based soy protein concentrate modified by the method described above has a solubility that is more than 60% higher than that of the raw material, and a foaming property that is more than 50% higher than that of the raw material; wherein, the solubility is calculated according to the following formula 1:

[0025] ;

[0026] Foaming properties are calculated according to the following formula 2:

[0027] ;

[0028] In the formula, This represents the initial volume (mL) of the protein solution. The total volume (mL) of foam is measured immediately after foaming.

[0029] Preferably, the modified alcohol-based soy protein concentrate obtained by the above method exhibits emulsifying activity that is more than 100% higher and emulsifying stability that is more than 30% higher than that of the unmodified alcohol-based soy protein concentrate; wherein, the emulsifying activity is calculated according to the following formula 3:

[0030] ;

[0031] Emulsion stability is calculated according to the following formula 4:

[0032] ;

[0033] In the formula, This is the dilution factor (250). Protein concentration (g / mL). A is the volume fraction of sunflower seed oil (0.2); A0 is the initial absorbance of the emulsion at 500 nm. 30 The absorbance is the absorbance after standing for 30 minutes.

[0034] Preferably, the emulsion obtained by pretreating the soy protein concentrate obtained by ultrasonication at 500 W for 8 min followed by papain enzymatic hydrolysis for 60 min with sunflower seed oil (after secondary ultrasonic treatment) exhibits a Turbiscan stability index (TSI) below 1.0 and a separation index (CI) below 5% within 60 min of storage at 25°C. The separation index is calculated according to the following formula:

[0035] .

[0036] Preferably, the plant-based milk prepared by the method has an average particle size of less than 5 μm, an absolute value of Zeta potential greater than 40 mV, and exhibits no stratification or oil separation after being stored at 25°C for 30 days.

[0037] More preferably, the protein is selected by ultrasonic hydrolysis at 500 W for 8 min and papain enzymatic hydrolysis for 60 min, and is then mixed with sunflower seed oil at a high-speed shear ratio of 4:1 (v / v) to form a pre-emulsion. 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, or 0.3% of triazine gum is slowly added, followed by a second shearing (10000 rpm, 3 min), and then sterilized at 85℃ for 30 min to form an emulsion gel.

[0038] More preferably, in the preparation method, the concentration of soybean protein concentrate is 4%, the ultrasonic power is 500 W for 8 min, the papain enzymatic hydrolysis temperature is 50℃, pH is 6.0, the time is 1 h, and the E / S ratio is 1:50; after mixing the protein solution with sunflower seed oil (4:1 v / v), it is sheared at 10000 rpm for 2 min; the polysaccharide is triacinol, the shearing speed is 10000 rpm for 3 min, the concentration is preferably 0.05%~0.3%, and the sterilization temperature is 85℃ for 30 min.

[0039] In addition, the secondary ultrasound of the emulsion (2 min, 300 W) was only used to screen parameters such as emulsifying activity, emulsifying stability, emulsion index, TSI index, particle size, and potential of the emulsion prepared by modified alcohol-based soybean protein concentrate and sunflower seed oil to determine the optimal parameters; the final preparation of the plant-based emulsion was carried out by high-speed shearing followed by direct addition of triazine gum, without the need for secondary ultrasound.

[0040] Preferably, in the preparation method, the order of ultrasonic pretreatment followed by enzymatic hydrolysis is significantly better than the order of enzymatic hydrolysis followed by ultrasonication in terms of foaming properties, solubility, emulsifying activity and emulsifying stability, and the resulting emulsion has a lower TSI value, smaller particle size and higher absolute value of Zeta potential.

[0041] Another technical objective of this invention is to provide a plant-based milk prepared by the above method and to apply it to the preparation of plant-based whipping cream or plant-based cooking milk. Specifically, this plant-based milk can form a weak gel network with a very low amount of triacin (0.05%~0.3%). After pasteurization at 85°C, it shows no stratification or oil separation after storage at 25°C for 30 days. Its steady-state shear behavior and frequency sweep curve are closest to those of commercially available whipping cream, exhibiting moderate shear thinning behavior and solid-like viscoelasticity, balancing good fluidity and structural strength. It can replace commercially available whipping cream in food processing fields such as baking, cooking, and beverage preparation.

[0042] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0043] 1. This invention combines ultrasonic pretreatment (500 W, 8 min) with precise enzymatic hydrolysis using papain (E / S = 1:50, 50℃, pH 6.0, 60 min). The sequence of ultrasonication followed by enzymatic hydrolysis effectively breaks down dense protein aggregates, exposing enzyme cleavage sites. The modified protein exhibits over 60% higher solubility, over 50% higher foaming properties, over 100% higher emulsifying activity, and over 30% higher emulsifying stability compared to the raw material. Scanning electron microscopy results show that the protein structure changes from sheet-like and rod-like structures to uniformly dispersed short rod-shaped particles.

[0044] 2. This invention screened triazine gum as a suitable polysaccharide, which can form a weak gel network at extremely low addition levels (0.05%~0.3%). After adding triazine gum, the average particle size of the emulsion gel decreased from 7.5 μm to below 5 μm, the absolute value of the Zeta potential increased by more than 25% (>40 mV), the Turbiscan stability index (TSI) significantly decreased from about 0.5 to about 0.25, and the emulsion separation index (CI) was below 5%. No stratification or oil separation occurred after 30 days of storage at 25°C.

[0045] 3. The plant-based milk prepared by this invention, after pasteurization at 85°C, exhibits steady-state shear behavior and frequency sweep curves (G′>G″) that are closest to those of commercially available light cream, demonstrating moderate shear thinning behavior and solid-like viscoelasticity, while maintaining good flowability and structural strength. It can replace commercially available light cream in food processing fields such as baking, cooking, and beverage preparation.

[0046] 4. This invention minimizes the use of chemical reagents, requiring only 85°C pasteurization for long-term stable storage, eliminating the need for high-intensity sterilization or large amounts of hydrophilic colloids, thus reducing equipment costs and energy consumption. This method successfully extends alcohol-based soy protein concentrate to high-end plant-based dairy products such as vegetable-based whipping cream and cooking milk, demonstrating broad market application prospects. Attached Figure Description

[0047] Figure 1 The images show the solution and emulsion states after SPC ultrasonic treatment. A shows the solution state after 8 min of SPC ultrasonic treatment at different power levels; B shows the solution state after SPC ultrasonic treatment (8 min, 500 W) with different proteases, and the emulsion state after 0 h and 4 h after mixing with sunflower seed oil at a 4:1 (v / v) ratio and ultrasonic treatment; C shows the emulsion state after SPC, SPC ultrasonic treatment, and SPC ultrasonic hydrolysis with papain at different times, mixed with sunflower seed oil at a 4:1 (v / v) ratio and ultrasonic treatment (1 day, 2 days, 3 days, 4 days).

[0048] Figure 2 The images show the state and stability of the polysaccharide-prepared emulsion gels. In the image, D shows the state of the emulsion gels after preparation with different types / concentrations of polysaccharides (6h); E shows the inverted image of the stabilized emulsion gel (6h) and the state of the emulsion gel after 3 days.

[0049] Figure 3 Viscosity and state graphs of light cream control group, SPC ultrasonic hydrolysis at 500 W for 8 min, enzymatic hydrolysis for 60 min, and the addition of different concentrations of triazine gum are shown. F represents the viscosity data of the light cream control group and the groups with added 0%, 0.1%, 0.3%, 0.5%, 0.7%, and 0.9% triazine gum; G represents the emulsion state graph of the corresponding samples (1 day).

[0050] Figure 4 Emulsion gelation state diagrams (15 days and 30 days) for the light cream control group and for the emulsion containing 0.05%~0.3% triazine added to U+E60 emulsion.

[0051] Figure 5 The graph shows the effects of ultrasonic treatment and different protease treatments on protein properties and emulsion properties. A represents the solubility results after ultrasonic treatment for different times / powers; B represents the foaming properties results after ultrasonic treatment for different times / powers; C represents the emulsifying activity (EAI) and emulsifying stability (ESI) results after ultrasonic treatment with different proteases; and D represents the emulsion separation index (CI) results after ultrasonic treatment with different proteases (4h).

[0052] Figure 6 The graph shows the effect of papain hydrolysis parameters (temperature, pH, enzyme dosage) on the degree of hydrolysis and emulsification activity.

[0053] Figure 7 Figure (A) shows the protein hydrolysis degree, emulsifying activity, emulsifying stability, and solubility results after SPC, SPC ultrasound, and SPC ultrasound + enzymatic hydrolysis for different times, and Figure (B) shows the emulsion separation index results.

[0054] Figure 8 Microscopic images (scanning electron microscope) of proteins after SPC, SPC ultrasound, and SPC ultrasound + enzymatic digestion for different times.

[0055] Figure 9The Turbiscan stability index of emulsions under different treatment conditions is shown in Figure A. A represents the results of the U+E60 emulsion (prepared by SPC ultrasonication at 500 W for 8 min; papain enzymatic hydrolysis for 60 min; mixed with sunflower seed oil at a 4:1 (v / v) shearing), SPC, SPC ultrasonication, and SPC ultrasonication + enzymatic hydrolysis for different times; B represents enlarged views of the results of SPC, SPC ultrasonication, and SPC ultrasonication + enzymatic hydrolysis for different times; C represents the results of the light cream control group and the U+E60 emulsion mixed shearing preparation with the addition of 0%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, and 0.3% triazine gum; D represents enlarged views of the results of the U+E60 emulsion mixed shearing preparation with the addition of 0%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, and 0.3% triazine gum.

[0056] Figure 10 The figures show the particle size and potential measurement results. A and B represent the particle size and potential measurement results of emulsions prepared by SPC, SPC ultrasound, and SPC ultrasound + enzymatic hydrolysis for different times followed by shear ultrasound. C and D represent the particle size and potential measurement results of the emulsion gel after adding different concentrations of triazine to the light cream control group and the U+E60 emulsion.

[0057] Figure 11 Rheological data for the control group of light cream and U+E60 emulsion with different concentrations of triazine gum are shown in the graphs. A represents the steady-state shear measurement results; B represents the frequency scan G' measurement results; and C represents the frequency scan G'' measurement results.

[0058] Figure 12 Microscopic images of U+E60 emulsion with different concentrations of triazine (optical microscope).

[0059] Figure 13 The bar chart shows the effect of different modification sequences on protein solubility and emulsion stability. A represents the comparison of foaming properties of SPC, E60+U, and U+E60 (values ​​are 1.66%, 20%, and 30%, respectively); B represents the foaming state of SPC, E60+U, and U+E60; C represents the comparison of solubility of SPC, E60+U, and U+E60 (values ​​are 30%, 41%, and 46%, respectively); and D represents the corresponding comparison of emulsion activity (values ​​are 14.4%, 17.75%, and 25.8%) and emulsion stability (values ​​are 98%, 101%, and 117%, respectively).

[0060] Figure 14The figures show the stability analysis, particle size distribution, and appearance after 1 day for emulsions with different modification sequences. Specifically, E compares the stability analysis data of SPC, E60+U, and U+E60 (U+E60 has the lowest TSI); F shows the appearance of the emulsions after 1 day; G compares the particle sizes of SPC, E60+U, and U+E60 (values ​​are 1472 nm, 769 nm, and 895 nm, respectively); and H compares the potentials of SPC, E60+U, and U+E60 (values ​​are -43 mV, -25 mV, and -57 mV, respectively).

[0061] Figure 15 The graph shows the effect of different modification sequences on the properties of the emulsion and gel. I is a bar chart comparing particle size (particle size of SPC, E60+U, U+E60, and emulsions / gels after adding 0.2%, 0.25%, and 0.3% triazine, respectively); J is a potential comparison chart (potential of SPC, E60+U, and U+E60 after adding 0.25% triazine, respectively); K is a steady-state shear chart (steady-state shear chart of the cream control group, SPC, E60+U, U+E60, and emulsions / gels after adding 0.2%, 0.25%, and 0.3% triazine, respectively); L is the upright (top row) and inverted (bottom row) graph of the emulsion / gel after 1 day; M / N is the frequency scan chart (frequency scan chart G' / G” of the cream control group, SPC, E60+U, U+E60, and emulsions / gels after adding 0.2%, 0.25%, and 0.3% triazine, respectively).

[0062] Figure 16 The following figures represent the melting state, melting rate, and sensory evaluation of ice cream after the addition of 0.2%, 0.25%, and 0.3% triazine-emulsion gel to the control group. Figure A shows the melting state (0 min, 30 min) of the ice cream with the whipped cream, ice cream completely replaced by 0.2%, 0.25%, and 0.3% triazine-emulsion gel, and ice cream completely replaced by 0.3% triazine-emulsion gel. Figure B shows the melting rate and first drip time analysis of the control group and the ice cream completely replaced by triazine-emulsion gel (0.2%, 0.25%, 0.3%). Figure C shows the sensory evaluation of the control group and the ice cream completely replaced by triazine-emulsion gel (0.2%, 0.25%, 0.3%). Detailed Implementation

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] Example 1: The effect of ultrasonic power and time selection on protein solubility

[0065] 4% (30 mL) of alcohol-based soy protein concentrate was placed on a magnetic stirrer and stirred uniformly at 300 rpm for 2 h. The solution was then placed in a 4°C refrigerator and hydrated overnight. This solution was labeled as SPC solution.

[0066] The probe of an ultrasonic cell disruptor is inserted 1–2 cm into the SPC solution for ultrasonic treatment, with a power of 0 W–700 W and a time of 0 min–20 min. For example: 0 W, 100 W, 300 W, 500 W, 700 W; 4 min, 8 min, 12 min, 16 min, 20 min.

[0067] Protein solubility was determined using biuret reagent. Twenty-five groups of solutions were centrifuged at 6000 r / min for 15 min after sonication. 1 mL of the supernatant was mixed with 4 mL of biuret reagent. After reacting in the dark for 30 min, the absorbance at 540 nm was measured using a UV-Vis spectrophotometer, and the soluble protein concentration was calculated based on the standard curve. Protein solubility was calculated according to Equation 1:

[0068] Protein solutions prepared at different times and power were sheared at 10000 rpm for 2 min using a high-speed disperser, and the foam height was immediately measured and calculated according to Equation 2:

[0069] When ultrasonic treatment is performed at 500 W for 8 minutes, the foaming capacity is approximately 50% (see...). Figure 5 B) Furthermore, the foaming ability is more significant when the time is <8 min. This may be because in the early stage of ultrasonic treatment (when the time is short), the aggregates of alcohol-processed soybean protein concentrate are moderately opened through cavitation effect and mechanical shear force, exposing an appropriate amount of hydrophobic and hydrophilic groups. This allows protein molecules to be rapidly adsorbed and oriented at the gas-liquid interface, forming a relatively flexible protein film, which is conducive to the rapid formation and stability of foam.

[0070] Protein dispersibility (see) Figure 1 A), solubility (see A) Figure 5 A) By utilizing cavitation and mechanical vibration to disrupt protein aggregates and non-covalent bonds, proteins can unfold, enhance protein-water interactions, and improve solubility and dispersibility. However, excessive sonication can cause hydrophobic groups to re-aggregate, forming insoluble aggregates and reducing solubility. The solution obtained under optimal conditions (8 min sonication, 500 W power) is labeled as solution U.

[0071] Example 2: Selection of enzyme types and their effect on emulsifying properties

[0072] Within the suitable conditions for different enzymes, the enzyme type, pH, temperature, enzyme dosage, and hydrolysis time of the U solution were screened according to the table below based on stability, emulsifying activity, etc.

[0073] Enzyme types pH Temperature (°C) Enzyme addition amount (%) Enzymatic hydrolysis time (min) neutral protease 7.0 50 2 60 alkaline protease 9.5 50 2 60 Papain 6.5 50 2 60 Bromelain 7.0 50 2 60 Flavor proteases 7.0 50 2 60 trypsin 8.0 37 2 60 pepsin 2.0 37 2 60

[0074] U solution was subjected to different enzymatic hydrolysis treatments (see...) Figure 1 B) was mixed with sunflower seed oil and sheared, then ultrasonically treated at 300 W for 2 min. The stability of the emulsion was observed (see [link]). Figure 1 B).

[0075] Quickly aspirate 20 μL of the emulsion from the bottom and mix thoroughly with 5 mL of SDS. Using a UV-Vis spectrophotometer, measure the absorbance of the sample solution at a wavelength of 500 nm and record this absorbance as A0. After standing for 30 min, repeat the above procedure, recording the absorbance as A0. 30 The emulsification activity of the sample is calculated using Equation 3, and the emulsification stability is calculated using Equation 4.

[0076] The emulsion stability was represented by the emulsion index (CI). Samples were stored in glass bottles and allowed to stand at room temperature for a period of time; the liquid level was then recorded. CI was calculated using Equation 5.

[0077] Experimental results are as follows Figure 5 As shown in C and 5D, the influence of different enzyme types on emulsions is as follows: papain, bromelain > neutral protease, pepsin > alkaline protease, flavor protease, trypsin. Endopeptides such as papain and bromelain, under specific hydrolysis levels, can produce medium-length peptides with amphiphilic properties, thus effectively improving emulsifying properties. Alkaline proteases and flavor proteases, however, either over-hydrolyze or have inappropriate mechanisms of action, thereby damaging the emulsifying structure of the protein. Therefore, papain was chosen as the enzyme responsible for protein emulsification.

[0078] Example 3: Selection of Enzyme Conditions

[0079] Within the suitable range of papain hydrolysis conditions, the pH of solution U was adjusted to 5.0, 6.0, and 7.0, the hydrolysis temperature was adjusted to 50℃, 60℃, and 70℃, and the enzyme addition amount was adjusted to E / S=1:100, E / S=1:50, and E / S=1:20. An orthogonal experimental method was set up to select the optimal conditions of pH 6.0, 50℃, and E / S=1:50 as the hydrolysis conditions for alcohol-based soybean protein concentrate, which were labeled as solution E.

[0080] The solubility and emulsifying activity of solution U under different enzymatic hydrolysis conditions were calculated using Equations 1 and 3 (see Equations 1 and 3). Figure 6 ).

[0081] Based on the analysis of solubility and emulsifying properties, papain exhibits the best performance at a temperature of 50℃, pH 6.0, and an enzyme addition ratio of E / S = 1:50, and is designated as solution E.

[0082] Example 4: The selection of enzymatic hydrolysis time of U solution and its effect on degree of hydrolysis, emulsifying properties and microstructure

[0083] Solution E, after ultrasonic modification, improved the dispersibility, solubility, and foaming properties of alcohol-processed soy protein concentrate. Enzymatic hydrolysis further enhanced the emulsifying properties of the soy protein concentrate. The enzymatic hydrolysis time of solution E was set at six levels: 15 min, 30 min, 60 min, 120 min, 180 min, and 240 min, labeled E15, E30, E60, E120, E180, and E240.

[0084] Adjust the pH of the enzymatically digested sample solution to neutral (pH 7.0), add pre-neutralized formaldehyde solution (using phenolphthalein as an indicator, titrated with NaOH until a faint pink color appears), to chelate the -NH3 in amino acids. + The group releases H + The solution is then made acidic again, and immediately titrated with standard NaOH solution to bring the pH from 8.2 to 9.2 (or until phenolphthalein indicator turns red). The amino acid nitrogen content is calculated based on the amount of alkali consumed in the titration, and then the degree of hydrolysis is obtained by combining the total nitrogen in the sample.

[0085] Formula 6:

[0086] ;

[0087] In the formula, AN2: amino acid nitrogen content of the sample after enzymatic hydrolysis (g / 100 mL)

[0088] AN1: Amino acid nitrogen content of the sample before enzymatic digestion (g / 100 mL, i.e., background value)

[0089] N: Total nitrogen content of the sample (g / 100 mL stock solution)

[0090] h _total The number of millimoles of peptide bonds per gram of protein (m mol / g) is typically taken as 7.8 for soy protein, 8.2 for casein, and approximately 8.0 for general proteins.

[0091] The methods for determining solubility, emulsifying activity, and emulsifying stability are shown in Equations 1, 3, and 4, respectively.

[0092] As the enzymatic hydrolysis time increases, the hydrolysis rate of soybean protein concentrate gradually slows down. The degree of hydrolysis rises rapidly in the early stage of the reaction, then the rate of increase slows down, and finally enters a plateau period. The enzymatic hydrolysis curve shows a trend of rapid increase followed by slow increase.

[0093] Compared to untreated alcohol-based soy protein concentrate, the solubility, emulsifying activity, and emulsifying stability of the soy protein concentrate improved by 61.6% after ultrasonic treatment and enzymatic hydrolysis, 106.8% after emulsifying activity, and 30% after emulsifying stability (U+E120). Overall, the functionally treated soy protein concentrate was superior to the untreated one (see...). Figure 7 A, B).

[0094] The microstructure of the samples was observed using a SEM (JSM6380LV, Japan Electronics, Japan) at 200× and 20 kV. SPC samples and SPC-treated samples (0.4 g / mL) were subjected to freeze-drying of the supernatant after centrifugation.

[0095] It is evident that ultrasonic treatment significantly affects the protein concentrate produced by the alcohol-based process. The protein structure was initially mostly sheet-like and rod-like, but after papain enzymatic hydrolysis, the protein structure changed from sheet-like and rod-like to short rod-like, and the structure gradually became more dispersed. At a hydrolysis time of 60 min, the protein particles were more uniform (see...). Figure 8 ).

[0096] Example 5: Selection of Emulsion Preparation Method

[0097] SPC solution, U solution, E15 solution, E30 solution, E60 solution, E120 solution, E180 solution, and E240 solution were mixed with sunflower seed oil at a ratio of 4:1 (v / v) and sheared. The emulsions were then subjected to secondary ultrasonic treatment at 300 W for 1-2 min. The instability of the emulsion over time was assessed using a Turbiscan (LAB Expert) stability analyzer via backscattering distribution curves. For each measurement, 20 mL of the emulsion sample was placed in the measurement cell, and the total saturation index (TSI) was automatically calculated by the instrument (see [link to measurement]). Figure 9 A, 9B). Figure 9 In A, U+E60 is an emulsion prepared by enzymatic hydrolysis of protein after sonication for 60 min (mixed shearing only), while the rest are emulsions prepared from the original protein sample and the protein treatment group (two sonications). Sonication can improve the stability of the emulsion. Figure 9 B is a magnified view of a portion of 9A, showing that the emulsion prepared by ultrasonic enzymatic hydrolysis of proteins for 60 min exhibits the best stability, and the stability of the emulsion after mixing, shearing, and ultrasonic preparation is also shown (see...). Figure 9 The stability of U+UE60 in A compared to emulsions (which only moderate shear) (see...) Figure 9 U+E60 in A is better.

[0098] Place the dispensed sample vials at room temperature (25°C) and allow them to stand. Observe the layering of the vials (see...). Figure 1 C). Based on TSI and vial storage stability charts, the optimal emulsion is the one with an emulsion concentration of 60 min, labeled U+E60 (meaning it is a pre-emulsion prepared by mixing only for shearing).

[0099] Example 6: Effects of Polysaccharide Types and Amounts on Emulsions

[0100] The U+E60 emulsion was uniformly mixed with different types of polysaccharides (guar gum, pectin, xanthan gum, konjac gum, k-carrageenan, gellan gum, locust bean gum, sodium alginate, triazine gum, sodium carboxymethyl cellulose) and placed in a high-speed shearing machine at 10,000 rpm for 3 to 8 minutes to achieve uniform mixing.

[0101] Different types of polysaccharides have different appropriate addition ranges.

[0102]

[0103] Polysaccharides were added in different amounts to increase the stability of the emulsion. The plant-based emulsion of soybean protein concentrate obtained through alcohol processing was then pasteurized. The optimal polysaccharide was selected based on its binding ability to the emulsion (whether the emulsion gelled into layers) and its gelling properties upon inversion. After standing for 6 hours, the guar gum, k-carrageenan, locust bean gum, sodium alginate, and sodium carboxymethyl cellulose groups all showed stratification. The gellan gum group had high viscosity and low content, exhibiting significant gelling upon inversion, which differed considerably from the control group. The three-pectin group, pectin group, konjac gum group, and xanthan gum group were selected (see...). Figure 2 D). Continue to let it stand for 3 days; the three-pronged gel group is the most stable (see...). Figure 2 E).

[0104] The concentration of triazine gum was analyzed. Thiazine gum concentrations of 0%, 0.1%, 0.3%, 0.5%, 0.7%, and 0.9% were compared with light cream (control group) and their viscosity was analyzed using a digital rotational viscometer (NDJ-9T) (see [link to analysis]). Figure 3 F), and an emulsion gel state diagram (see F). Figure 3As can be seen from G), compared with light cream (control group), the viscosity of the emulsion after enzymatic hydrolysis was significantly reduced (15.38 cP) and unstable layering was observed. When 0.1%–0.5% of triazine gum was added, the viscosity of the system quickly recovered and stabilized between 44.45 and 46.58 cP due to the thickening network effect of polysaccharides in the continuous phase. However, when the concentration was further increased to 0.7% and 0.9%, the excessively high concentration of hydrophilic colloid caused a change from a highly fluid state, and the sample did not flow when inverted, so a stable flow viscosity could not be measured. In order to seek the optimal balance between emulsion stability and flowability, this experiment ultimately selected light cream (control group) as the control and precisely targeted the fluid / weak network range of 0.05%–0.3% for long-term stability monitoring over 15 and 30 days.

[0105] Example 7: Particle size potential of emulsions and emulsion gels

[0106] The particle size and zeta potential of the emulsion were determined using a zeta potential and particle size analyzer. Fresh emulsions or emulsion gels were diluted 100-fold with deionized water before measurement.

[0107] Emulsion prepared by mixing modified soy protein concentrate with sunflower seed oil and subjecting it to shearing and ultrasonic treatment:

[0108] 1. The particle size of the emulsion prepared by ultrasonic enzymatic hydrolysis of protein was reduced by 35.71% compared with that prepared from untreated protein (see...). Figure 10 A) Because SPC contains non-protein impurity aggregates, which interfere with the change in average particle size.

[0109] 2. Sonication cavitation opens the protein structure, exposing a large number of negatively charged carboxyl groups. This increases the charge, and after enzymatic hydrolysis, the amino (positive) and carboxyl (negative) charges easily cancel each other out, resulting in minimal change in emulsion potential (see...). Figure 10 B).

[0110] U+E60 emulsion was prepared by shearing and then mixed with triazine of different concentrations to prepare emulsion gels:

[0111] 1. The particle size of a 0% triazine gel emulsion is as high as 7.5 μm. However, with the addition of low concentrations of triazine, the oil droplets can be stabilized, preventing them from agglomerating and reducing the particle size to 5 μm. As the concentration increases, triazine, while stabilizing the emulsion, promotes the proximity of oil droplets and impurity aggregates, thus stabilizing the emulsion and preventing stratification (see...). Figure 10 C Figure 12 ).

[0112] 2. The potential of the emulsion gel with added triazine was increased by 25% compared with that without triazine. Soy protein concentrate and triazine both carry negative charges and repel each other. Triazine, an anionic polysaccharide, provides additional negative charge and enhances the electrostatic stability and weak gel network of the system through complex formation.

[0113] Experimental Example 8: Stability and Rheological Properties of Alcohol-Processed Soy Protein Concentrate Plant-Based Milk

[0114] Analysis of the emulsion index of different emulsion gels revealed that the viscosity of Sanzan gel was too high at concentrations above 3%. Therefore, low-concentration screening of Sanzan gel was conducted (see...). Figure 2 E), and selected three-pronged gel to be added to the emulsion after shearing, heated at 85°C for 30 min and cooled before rheological analysis.

[0115] The rheological properties of the emulsion gels were analyzed using a 35 mm diameter rotational rheometer (MARS 60). All samples were tested at 25 °C, and the apparent viscosity and frequency sweeps of the emulsion gels were recorded. Apparent viscosity measurements were taken from 0.1 to 100 s⁻¹. -1 The shear rate range was determined. The linear viscoelastic region (LVR) was studied using a frequency range of 0.1–100 Pa·s (1 Hz), with a frequency scan of 0.1–100 Hz performed under a shear force of 1 Pa.

[0116] The steady-state shear and frequency sweep properties of emulsion gels with polysaccharide concentrations of 0.2%–0.3% (0.2% SAN, 0.25% SAN, 0.3% SAN) were most similar to those of light cream (control group) (see [reference]). Figure 11 ).

[0117] The stability of the emulsion gel was determined using the method described in Example 5. After adding (0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%) of triazine to the emulsion, followed by heating at 85°C for 30 min and cooling, the TSI value of the resulting emulsion gel significantly decreased from approximately 0.5 to approximately 0.25 compared to the emulsion without triazine (secondary sonication, used only for data comparison). The stability of the emulsion gel in the protein modification-emulsion shearing-polysaccharide complex system was much greater than that of the emulsion prepared by shearing sonication (see Example 5). Figure 9 C); where Figure 9 D is Figure 9 A magnified view of part of C.

[0118] Microstructural observations revealed that without the addition of triazine, the emulsion droplets were relatively large and had a weak ability to stabilize non-protein impurity aggregates. With increasing triazine addition, the droplet size gradually decreased, and the droplets moved closer to the non-protein impurity aggregates, effectively stabilizing impurities in the system and improving the overall stability of the emulsion gel (see...). Figure 12 ).

[0119] Furthermore, in a comparison of appearance after 30 days of storage at 25°C, the emulsion gel with 0.2%–0.25% triazine added most closely resembled the appearance of the commercially available light cream control group (see...). Figure 3 (F) No obvious stratification or oil separation was observed.

[0120] Experiment Example 9: The effect of the order of modification methods for alcohol-based soybean protein concentrate plant-based emulsion on the properties of protein, emulsion, and plant-based emulsion.

[0121] The foaming properties of SPC (soybean protein concentrate produced by alcohol-based digestion), E60+U (soybean protein concentrate produced by alcohol-based digestion and enzymatic hydrolysis at 500 W for 8 min after 60 min of enzymatic hydrolysis at 500 W for 8 min), and U+E60 (soybean protein concentrate produced by alcohol-based digestion and enzymatic hydrolysis at 500 W for 8 min followed by 60 min of enzymatic hydrolysis) were compared (see...). Figure 13 A) Solubility (see...) Figure 13 C) Emulsifying properties (see...) Figure 13 Analysis (D) revealed that the U+E60 group exhibited the best foaming ability and foam stability, significantly outperforming the SPC and E60+U groups. This is because ultrasonic pretreatment first opens the dense aggregates of the alcohol-based SPC through cavitation, exposing more enzyme action sites. Subsequently, the precise hydrolysis by papain produces more medium-length peptides with good amphiphilicity, which facilitates rapid adsorption and foam stabilization at the gas-liquid interface. In contrast, enzymatic hydrolysis followed by ultrasonication (E60+U) may lead to excessive depolymerization or re-aggregation of hydrophobic groups after partial unfolding of protein fragments following enzymatic hydrolysis, thus reducing foaming performance.

[0122] The U+E60 group exhibited the highest solubility, emulsifying activity (EAI), and emulsifying stability (ESI), representing increases of approximately 61.6%, 106.8%, and 30%, respectively, compared to the raw material SPC. The sequence of sonication followed by enzymatic hydrolysis more effectively disrupts protein aggregates and controls the degree of hydrolysis, avoiding over-enzymatic hydrolysis that could damage the emulsion structure.

[0123] Stability analysis of emulsions prepared by SPC, E60+U, and U+E60 (see...) Figure 14 E) Emulsion state diagram (see...) Figure 14 F), particle size ( Figure 14 G), potential (see G), Figure 14 Analysis was performed on H) regarding emulsion stability. Figure 14The E60 emulsion (E, 14F) and U+E60 emulsion had the lowest TSI value. The emulsion state diagram showed that it remained the most homogeneous and exhibited no significant stratification even after two ultrasonic treatments, significantly superior to the SPC and E60+U groups. This is closely related to the emulsion's microstructure (particle size, potential). Figure 14 The G and H results showed that the U+E60 emulsion had the smallest average particle size (significantly lower than SPC and E60+U) and a larger absolute value of Zeta potential, indicating that the protein was better adsorbed at the oil-water interface after sequential modification, forming smaller oil droplets with more stable surface charges, thereby effectively inhibiting emulsification and aggregation.

[0124] The particle size of the emulsion gels prepared by adding 0.2%, 0.25%, and 0.3% of triazine to SPC, E60+U, and U+E60, respectively (see [reference]). Figure 15 I), Potential (see Figure 15 J), steady-state shear (see Figure 15 K), frequency scan (see Figure 15 M, N) and diagrams of the upright and inverted states of the emulsion gel (see...) Figure 15 L), further addition of SAN to form an emulsion gel (0.2%, 0.25%, 0.3%). Figure 15 I and J showed that the U+E60 emulsion gel maintained a smaller particle size and a higher absolute value of the zeta potential. The synergistic effect between the triazine gel and the U+E60 modified protein was stronger, providing both additional electrostatic repulsion and effectively anchoring oil droplets and non-protein aggregates through a weak gel network.

[0125] Rheological properties ( Figure 15 K, M, N) further confirmed the superiority of the U+E60+triplex gum system. Its steady-state shear curve and frequency scan (G', G'') were closest to those of commercially available whipping cream (control group), exhibiting moderate shear thinning behavior and solid-like viscoelasticity (G' > G''), ensuring both good flowability and sufficient structural strength. Figure 15 The upright / inverted state diagrams of L visually show that the U+E60+0.2%~0.3% SAN group can still maintain good morphological stability after inversion, which is highly similar to that of whipped cream; while the SPC group showed obvious stratification when 0.2% stannin was added, and the E60+U group showed poor structural strength and morphological stability, which was significantly different from that of whipped cream.

[0126] Example 10:

[0127] By applying the prepared emulsion gels to products (e.g., ice cream), and analyzing their physicochemical properties (e.g., particle size, potential, rheology, microstructure) and appearance, 0.2%, 0.25%, and 0.3% triazine gum-emulsion gels were selected as substitutes for whipped cream, and their substitution effects were verified when added to ice cream. The ice cream sample formula consisted of: granulated sugar, skim milk powder, soy lecithin, monoglycerides, locust bean gum, whipped cream (35% fat content), and water. The substitute sample used an emulsion gel (20% fat content) to replace the whipped cream. First, dissolve granulated sugar and skim milk powder in water at 50℃. Then, slowly add soybean lecithin, monoglycerides, and locust bean gum to the aqueous phase. Finally, add light cream (0.2%, 0.25%, and 0.3% of triglyceride-emulsion gel are used to replace all of the ingredients). After mixing and stirring, pasteurize at 62-65℃ for 30 min, then homogenize twice (20 MPa and 40 MPa). After aging for 6 h, place the sample in a quick-freezing oven for beating and preparation. The collected sample is then hardened at -20℃ for 24 h.

[0128] Ice cream melting rate: The ice cream was weighed and placed on a standard sieve (10 squares) to form a certain amount of hardened ice cream clumps. A beaker was placed below the sieve assembly, and the system temperature was maintained at 25±1℃. The initial droplet formation time (Ts) and the percentage of melting after 30 minutes were recorded to measure the melting rate of the ice cream. The melting rate gradually increased with increasing triazine concentration because an appropriate amount of stabilizer can increase the viscosity of the slurry, helping to trap more air. Air can slow down heat transfer and delay ice crystal melting. Therefore, with the addition of high-concentration triazine, the viscosity increases, there are fewer air bubbles blocking heat, and the ice crystals melt faster (see...). Figure 16 (A, 16B). At the same time, although the over-crosslinked gel network can maintain its shape initially, once some ice crystals melt, it makes it easier for the liquid phase (whey) to separate and drip, accelerating the overall melting.

[0129] Texture analysis and sensory evaluation of ice cream: The sample testing speed was 1 mm / s before testing, 5 mm / s during testing, and 5 mm / s after testing. Regarding the hardness changes of the fully substitute ice cream: lower hardness usually means a weaker structural network, poorer support capacity of ice crystals / bubbles / fat globules, easier heat penetration, and thus faster melting rate. The texture analysis data of each group of ice cream are shown in Table 1.

[0130] Table 1. Texture analysis data of each group of ice cream sample hardness Adhesion elasticity chewing Adhesion cohesion responsive Whipped cream - ice 84.16±2.65 -29.82±1.25 0.76±0.21 10.57±1.2 13.9±1.21 0.17±0.01 2.42±0.42 0.2% SAN-ice 729.23±10.51 -21.13±0.98 1±0.13 122.68±6.54 122.68±11.24 0.17±0.04 1.33±0.22 0.25% SAN-ice 195.35±6.79 -25.35±3.31 1±0.14 27.34±2.42 27.34±3.52 0.14±0.02 1.04±0.08 0.3% SAN-ice 134.35±9.53 -21.14±1.42 1±0.26 20.58±3.25 20.58±2.65 0.15±0.03 1.16±0.12

[0131] Sensory evaluation was conducted according to the sensory evaluation operation specifications stipulated in GB / T 47328.2-2026 "Sensory Analysis of Milk and Dairy Products - Part 2: Sensory Analysis Methods" (effective August 1, 2026). The recruitment, screening, and training of evaluators followed the relevant provisions of GB / T 16291.1-2012 "General Guidelines for the Selection, Training, and Management of Sensory Analysis Evaluators - Part 1: Selection of Top Evaluators" (current). Based on the above standards, 10 evaluators (5 males and 5 females) were recruited, screened, and trained to form an evaluation team. Quantitative descriptive analysis (QDA) was used, employing a 0-9 linear scale to score the intensity of sensory attributes such as bean flavor, icy texture, and overall acceptability of the four ice cream samples. The evaluation results are as follows: Figure 16 As shown in C: the bean flavor of the fully substituted samples was moderate; the 0.3% triazine gum-emulsion gel-ice cream had the highest ice crystal intensity score, while the ice crystal intensity score of the 0.25% triazine gum-emulsion gel-ice cream was not significantly different from the control group; the overall acceptability score of the ice cream in the cream-substitute group was slightly lower than that in the control group (see...). Figure 16 C).

[0132] In summary, the sequence of ultrasonic pretreatment followed by enzymatic hydrolysis (U+E60) fully leverages the synergistic effect of the physical field's opening effect on protein aggregates and the precise hydrolysis effect of enzymatic hydrolysis, significantly outperforming the sequence of enzymatic hydrolysis followed by ultrasonication (E60+U). The proteins modified in this sequence exhibit the best performance in terms of functional properties, emulsion stability, and the weak gel network formed when combined with triazine gum, providing an optimal process route for preparing highly stable plant-based emulsions with rheological properties similar to light cream.

Claims

1. A method for preparing modified alcohol-based soy protein concentrate suitable for plant-based milk preparation, characterized in that, Includes the following steps: S1. Using alcohol-based soy protein concentrate as raw material, prepare a protein solution and hydrate it by stirring; S2. The solution is pretreated with ultrasound, and then the pH value is adjusted; S3. Add papain for enzymatic hydrolysis, then inactivate the enzyme; S4. The enzymatically hydrolyzed solution is mixed with vegetable oil and sheared at high speed to obtain a pre-emulsion; S5. Add triazine gum to the pre-emulsion, mix and shear, then pasteurize and cool to obtain plant-based emulsion.

2. The method for preparing modified alcohol-based soy protein concentrate suitable for plant-based milk preparation according to claim 1, characterized in that, The protein solution concentration in step S1 is 2%~6% (w / w), the stirring speed is 200~600 rpm, the stirring time is 1~3 h, and the hydration condition is 4℃ overnight.

3. The method for preparing modified alcohol-based soy protein concentrate suitable for plant-based milk preparation according to claim 1, characterized in that, The ultrasonic pretreatment in step S2 has a power of 100~700 W and a time of 0~20 min.

4. The method for preparing modified alcohol-based soy protein concentrate suitable for plant-based milk preparation according to claim 1, characterized in that, The papain hydrolysis conditions described in step S3 are as follows: the amount of enzyme added is 0.5% to 5% of the protein content of the alcohol-based soybean concentrate, E / S = 1:200 to 1:20, the hydrolysis temperature is 50 to 60℃, the pH is 5.0 to 7.0, and the hydrolysis time is 15 to 240 min; the enzyme inactivation conditions are a water bath at 85 to 95℃ for 5 to 15 min.

5. The method for preparing modified alcohol-based soy protein concentrate suitable for plant-based milk preparation according to claim 1, characterized in that, The vegetable oil mentioned in step S4 is sunflower seed oil, and the volume ratio of sunflower seed oil to protein solution is 3:1 to 5:1, the shearing speed is 8000 to 12000 rpm, and the time is 1 to 3 min.

6. The method for preparing modified alcohol-based soy protein concentrate suitable for plant-based milk preparation according to claim 1, characterized in that, In step S5, the mass concentration of the triazine in the final emulsion is 0.01%~0.7% (w / w), the homogenization speed is 8000~12000 rpm, and the time is 2~5 min; the pasteurization conditions are 80~90℃ for 20~40 min, and then cooled to 0~10℃.

7. The method for preparing modified alcohol-based soy protein concentrate suitable for plant-based milk preparation according to claim 1, characterized in that, The composition of the raw material for the alcohol-based soybean protein concentrate, by weight percentage, is as follows: 65%~71% protein, 0.19% fat, ≤2.71% fiber, 5.8%~7.0% ash, 5.5%~7.5% moisture, and approximately 20.8% carbohydrates.

8. The method for preparing modified alcohol-based soy protein concentrate suitable for plant-based milk preparation according to claim 1, characterized in that, The modified alcohol-based soy protein concentrate obtained by the above method has a solubility that is more than 60% higher than that of the raw material, a foaming property that is more than 50% higher than that of the raw material, an emulsifying activity that is more than 100% higher than that of the unmodified alcohol-based soy protein concentrate, and an emulsifying stability that is more than 30% higher than that of the unmodified alcohol-based soy protein concentrate.

9. The method for preparing modified alcohol-based soy protein concentrate suitable for plant-based milk preparation according to claim 1, characterized in that, The ultrasonic pretreatment power was 500 W for 8 min, and the papain enzymatic hydrolysis time was 60 min. The emulsion obtained by emulsifying the resulting alcohol-based soybean protein concentrate with sunflower seed oil had a Turbiscan stability index (TSI) of less than 1.0 and a separation index (CI) of less than 5% within 60 min of storage at 25°C. The plant-based milk prepared by the above method had an average particle size of less than 5 μm, an absolute value of zeta potential of greater than 40 mV, and showed no stratification or oil separation after 30 days of storage at 25°C.

10. The application of the plant-based milk prepared by the modified alcohol-based soy protein concentrate preparation method according to any one of claims 1 to 9 in the preparation of plant-based cream or plant-based cooking milk.

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