Preparation of sodium caseinate substitute and application of sodium caseinate substitute in plant-based coconut juice beverage

Abstract

The invention discloses preparation of a sodium caseinate substitute and application of the sodium caseinate substitute in a plant-based coconut juice beverage, and belongs to the technical field of plant protein processing. The method comprises the following steps: mixing bean flour with water, then inoculating compound bacteria for fermentation, and after the fermentation is finished, drying to stop the fermentation to prepare the fermented bean flour, then carrying out gradient washing by using ethanol solutions with different concentrations, filtering and drying to obtain alcohol-washed bean flour; protein is extracted through an alkali-solution and acid-isolation method, and protein isolate is prepared through redissolution and freeze-drying; and finally, stirring, homogenizing and sterilizing the protein isolate, the freshly squeezed coconut juice, cane sugar and other ingredients to prepare the plant-based coconut juice beverage. A large amount of volatile beany flavor substances such as aldehydes and alcohols are effectively degraded and removed through the processes such as compound bacterium suspension fermentation and gradient ethanol washing, the nitrogen dissolution index and the emulsification characteristic of the bean protein are synchronously improved, and the prepared pure plant-based coconut juice has the characteristics of no beany flavor, good flavor and fine taste.

Description

Technical Field

[0001] This invention relates to the field of plant protein processing technology, and in particular to the preparation of a sodium caseinate substitute and its application in plant-based coconut milk beverages. Background Technology

[0002] Plant-based dairy products are developing rapidly due to their health and sustainability advantages. Coconut milk, as a popular category, relies heavily on its rich taste, pure flavor, and long-term stability. Currently, high-end coconut milk often relies on adding animal-derived proteins (such as sodium caseinate) to increase protein content, improve texture, and enhance stability. However, this contradicts the "purely plant-based" positioning and fails to meet specific needs such as those of vegetarians.

[0003] Soybean and other legume proteins are nutritionally complete and are ideal candidates to replace sodium caseinate. However, their direct application faces two major bottlenecks: First, the inherent "beany" taste of natural proteins (mainly due to volatile substances such as hexanal produced by lipoxygenase) can seriously interfere with the main flavor of coconut milk; second, their functional properties (solubility, emulsification, and thermal stability) are insufficient in complex beverage systems, which can easily lead to sedimentation, layering, or a rough texture.

[0004] Existing deodorization technologies each have limitations: physical or enzymatic treatments are incomplete and may damage proteins; microbial fermentation processes are complex and poorly controllable; while conventional single-concentration ethanol washing can remove some off-odors, it is difficult to balance efficient removal with maintaining protein functional structure. Therefore, there is an urgent need to develop a pretreatment process that can simultaneously and efficiently address both flavor and functional defects for the production of high-quality plant-based coconut milk beverages.

[0005] Furthermore, in the prior art, patent CN 116439312 A (Preparation and Application of a Plant-Based Sodium Caseinate Substitute) discloses a technical solution for preparing a plant-based sodium caseinate substitute through plant protein sieving, solubilization and activation treatment, graded extraction, moderate modification, natural cross-linking agent modification, and freeze-drying. However, the plant-based sodium caseinate substitute obtained by this technical solution is used in the preparation of pure plant-based butter and is unrelated to pure plant-based coconut milk. Moreover, this solution aims to directionally alter the structure of plant proteins through a complex combination of physical, biological enzyme, and natural cross-linking agent processes to mimic the functional properties of sodium caseinate in emulsion (especially butter) systems (such as emulsification, stability, and foaming properties). Its technical approach focuses on the deep modification of protein structure-activity relationships, while the targeted removal of inherent undesirable flavors (such as beany taste) of bean raw materials is not its core objective. Simultaneously, this preparation process involves multiple steps of purification, incubation, cross-linking, and freeze-drying, resulting in a lengthy process, high energy consumption, and increased production complexity and cost. Summary of the Invention

[0006] Technical issues Existing high-end coconut milk relies on animal-derived protein to improve quality, which contradicts its pure plant-based positioning. Soy protein, as a candidate for alternative, faces two major bottlenecks: firstly, the natural beany taste interferes with the flavor of coconut milk; secondly, its insufficient functional properties easily lead to product sedimentation and stratification. Existing deodorization technology cannot simultaneously achieve efficient deodorization and maintain the functional structure of proteins, so there is an urgent need to develop a pretreatment process that addresses both flavor and functional defects.

[0007] Technical content To address the aforementioned technical problems, this invention provides a method for preparing a sodium caseinate substitute and its application in plant-based coconut milk beverages. Low-temperature defatted soybean meal or soybean seeds are pulverized into powder and fermented with a compound microbial culture to obtain fermented soybean flour; ethanol-washed soybean flour is obtained by washing with ethanol; isolated protein is then prepared through alkali dissolution and acid precipitation; finally, the isolated protein is mixed with freshly squeezed coconut juice, sucrose, and other ingredients, stirred, homogenized, and sterilized to produce a plant-based coconut milk beverage. This invention effectively degrades and removes a large amount of volatile beany substances such as aldehydes and alcohols, resulting in a pure plant-based coconut milk with no beany taste, good flavor, and a delicate texture.

[0008] This invention first provides a method for preparing a sodium caseinate substitute for plant-based coconut milk beverages, the preparation method comprising the following steps: (1) Preparation of fermented soybean flour: Mix soybean flour and water, add compound bacterial suspension, stir evenly, seal and ferment at 37-40 ℃ for 18-24h, dry after fermentation to obtain fermented soybean flour; (2) Preparation of alcohol-washed soybean powder: The fermented soybean powder prepared in step (1) is mixed with ethanol solution S1 and stirred for 40-80 minutes. After filtering to remove the ethanol, the resulting solid is mixed with ethanol S2 and stirred for 40-80 minutes. After filtering to remove the ethanol, the solid is collected and dried to remove the ethanol, thus obtaining alcohol-washed soybean powder. (3) Preparation of isolated protein: Mix the alcohol-washed soybean powder prepared in step (2) with water, adjust the pH to 9.0-10.5, stir for 30-90 minutes, and centrifuge to remove the precipitate; adjust the pH of the supernatant to 4.0-5.0, stir for 30-90 minutes, centrifuge to collect the precipitate, mix the precipitate with water, centrifuge to collect the precipitate; mix the precipitate with water again, stir thoroughly, adjust the pH to 6.8-7.5 until completely dissolved, centrifuge to collect the supernatant to obtain the protein neutralization solution; freeze-dry the protein neutralization solution under vacuum to prepare the sodium caseinate substitute.

[0009] Furthermore, the soybean flour mentioned in step (1) is a powder made by crushing defatted soybean meal or soybean seeds.

[0010] Furthermore, the defatted soybean meal is a high-protein byproduct obtained after soybeans have undergone pressing or solvent extraction processes to remove most of the oil.

[0011] Furthermore, the legume seeds include peas and chickpeas.

[0012] Furthermore, the mixing ratio of soybean flour and water in step (1) is 1:0.5-2.

[0013] Furthermore, the bacteria in the compound bacterial suspension mentioned in step (1) are Bacillus subtilis CICC20641, Lactobacillus plantarum subsp. plantarum CICC2098 and Saccharomyces cerevisiae CICC1015.

[0014] Furthermore, the mass ratio of Bacillus subtilis to Lactobacillus plantarum subsp. plantarum was 1:1-2.

[0015] Furthermore, the mass ratio of Bacillus subtilis to Saccharomyces cerevisiae is 1:1-2.

[0016] Furthermore, the total amount of bacteria added to the compound bacterial suspension is 1-1.5 × 10⁻⁶ per gram of soybean flour. 7 CFU.

[0017] Furthermore, the 1.0-1.5×10 of the compound bacterial suspension mentioned in step (1) 8 CFU / mL.

[0018] Furthermore, the amount of compound bacterial suspension added in step (1) is 10-15 wt% of soybean flour.

[0019] Furthermore, the drying conditions in step (1) are drying at 45-55 ℃ for 20-30 hours.

[0020] Furthermore, in step (2), the alcohol content of ethanol solution S1 is 80-85%, and the mixing ratio with fermented soybean powder is 1:5-1:15 (w / v); the alcohol content of ethanol solution S2 is 90-95%, and the mixing ratio with fermented soybean powder is 1:3-1:8 (w / v).

[0021] Furthermore, in step (2), the drying conditions are 45-55°C for 9-15 hours.

[0022] Furthermore, in step (2), ethanol removal can also be achieved by vacuum rotary evaporation, with the conditions being a temperature of 45-55°C and a time of 1-2 h.

[0023] Furthermore, in step (3), the mixing volume of alcohol-washed soybean powder and water is 1:5-1:15.

[0024] Furthermore, in step (3), the mixing volume of the precipitate and water is 1:5 to 1:15.

[0025] Furthermore, the vacuum freezing conditions in step (3) are -30 to -20°C for 12 to 24 hours.

[0026] Furthermore, in step (3), the pH solution is adjusted to a sodium hydroxide or hydrochloric acid solution.

[0027] Furthermore, in step (3), the centrifugation conditions are 7000-9500 rpm and the centrifugation time is 30-60 minutes.

[0028] The present invention provides a sodium caseinate substitute for plant-based coconut milk beverages prepared according to the above preparation method.

[0029] The present invention also provides the use of the prepared sodium caseinate substitute in coconut milk beverages.

[0030] Furthermore, the application involves dissolving a sodium caseinate substitute in water to prepare a protein solution, then mixing freshly squeezed coconut juice and sucrose with the protein solution, adjusting the pH to neutral, stirring until completely dissolved, and then performing high-pressure homogenization and UHT sterilization to obtain plant-based coconut juice.

[0031] Furthermore, freshly squeezed coconut juice contains 35-40% total solids, 30-35% fat (dry basis), and 3-5% protein (dry basis).

[0032] Furthermore, the preparation of freshly squeezed coconut juice is as follows: take a fresh coconut, open the shell to remove the coconut meat, cut it into pieces, mix the coconut meat and water and blend for 5-8 minutes, then filter to obtain freshly squeezed coconut juice.

[0033] Furthermore, the plant-based coconut juice contains 0.6-0.8 wt% sodium caseinate substitute, 6-7 wt% freshly squeezed coconut juice, 4.0-5.5 wt% sucrose, and the remainder is water.

[0034] Furthermore, the pH-adjusting substances include baking soda, sodium citrate, or sodium carbonate; all of these substances are food-grade.

[0035] Furthermore, the neutral pH is 6.5-7.5.

[0036] Furthermore, the high-pressure homogenization pressure is 40-45 MPa.

[0037] Furthermore, the UHT sterilization temperature is 135-140℃, and the temperature is maintained for 10-20 seconds.

[0038] Finally, this invention provides plant-based coconut milk prepared according to the above applications.

[0039] Beneficial effects 1. Significantly improved flavor: Through mixed-culture fermentation and gradient ethanol washing, most of the unpleasant small-molecule flavor substances such as aldehydes and alcohols are effectively removed, fundamentally solving the beany taste problem. The resulting plant-based coconut juice beverage has a pure flavor and is more easily accepted by consumers.

[0040] 2. Enhanced functional properties: This process technology effectively improves the nitrogen solubility index and emulsification characteristics of proteins, enhances their stability in complex systems, and makes the final product more delicate in texture, less prone to separation and sedimentation.

[0041] 3. The process parameters of this invention have been carefully optimized and clearly defined, making them applicable not only to soy protein but also to pea protein and chickpea protein, demonstrating good raw material versatility. The process is stable, reproducible, and easy to scale up, providing a reliable alternative to animal protein for the food industry. Attached Figure Description

[0042] Figure 1 This is a process flow diagram of the sodium caseinate substitute of the present invention and its application in plant-based coconut milk beverages.

[0043] Figure 2 The appearance diagrams of coconut juice obtained in all embodiments 1-4 of this invention are shown. Detailed Implementation To make the above-mentioned objects, features, and advantages of the present invention more apparent, the present invention will be described in detail below with reference to specific embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention. Modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and substance of the invention are all within the scope of the present invention.

[0044] Test methods 1. Determination of volatile flavor compounds Sample pretreatment was performed as follows: 0.3 g of protein powder was dissolved in 6.0 g of 16.0% NaCl solution to obtain a protein sample; and 1.5 g of coconut milk was dissolved in 3.5 g of 16.0% NaCl solution to obtain a coconut milk sample. HS-SPME was performed using PDMS (50 microns) SPME fiber (Shanghai Anpu, China) under the following conditions: extraction at 60°C for 330 minutes with a stirring speed of 270 rpm.

[0045] GC-MS (SCION SQ 456, Bruker, Bremen, Germany) was performed on a fused silica capillary column DB-WAX (30 m × 0.25 mm, Agilent DB-WAX). The column was held at 40 °C for 3 min, and the oven temperature was increased from 40 °C to 90 °C at 5 °C / min, and then to 250 °C at 10 °C / min. During the run, the injector and detector temperatures were set to 250 °C in splitless mode. The mass spectrometer was operated in electron collision (EI) mode. The ionization energy, detector voltage, scan range, and scan rate used for analysis were 70 eV, 350 V, 33–450 m / z, and 3.00 / s, respectively. Quantification was performed using the internal standard method.

[0046] 2. Nitrogen solubility index determination At room temperature (25°C), approximately 1.0 g of protein was dissolved in 50 ml of deionized water. The pH was adjusted to 7.0 using 0.5 M NaOH or HCl. The solution was then magnetically stirred for 1 hour. Subsequently, the mixture was centrifuged at 4000 rpm for 20 minutes. The protein content in the sample and supernatant was determined by the Kjeldahl method and calculated using the following formula.

[0047]

[0048] 3. Emulsification property determination The emulsifying property was determined by turbidimetric method. The protein sample was diluted with 10 mmol / L phosphate buffer (pH 7.0) to a protein concentration of 0.3% (w / w). 9 mL of the protein solution and 1 mL of sunflower oil were pipetted into a beaker, and the solution was sheared at 12000 rpm for 2 minutes. Then, 80 μL of the emulsion was taken from the bottom and added to 8 mL of SDS solution (0.1%, w / w) and mixed thoroughly. The absorbance of the mixture was measured at 500 nm and recorded as A0. After 10 minutes, another 80 μL of the emulsion was taken from the bottom and added to 8 mL of SDS solution (0.1%, w / w) and mixed thoroughly. The absorbance of the mixture was measured at 500 nm and recorded as A0. 10 The formulas for calculating emulsifying activity (EAI) and emulsifying stability (ESI) are as follows:

[0049]

[0050] In the formula, A0 is the absorbance at 0 minutes; N is the dilution ratio (100); C is the concentration of emulsified protein (0.003 g / mL); φ is the volume fraction of oil (0.1); A 10 It is the absorbance value at 10 minutes.

[0051] Source of raw materials The low-temperature defatted soybean meal used in the embodiments and comparative examples of this invention was purchased from Shandong Yuwang Ecological Food Industry Co., Ltd.; the peas and chickpeas were purchased from the local trade market in Wuxi; Bacillus subtilis CICC 20641, Lactobacillus plantarum subsp. plantarum CICC20988, and Saccharomyces cerevisiae CICC1015 were purchased from the China Industrial Microbial Suspension Preservation and Management Center; the freshly pressed coconut juice was purchased from Guangzhou Nanyi Import and Export Trading Co., Ltd., with a total solids content of 38.3%, a fat content of 32.0% (dry basis), and a protein content of 3.1% (dry basis); sodium caseinate was purchased from Fonterra Group of New Zealand; and the sunflower seed oil and sucrose were purchased from the local market.

[0052] Example 1 (1) Preparation of fermented soybean flour: Low-temperature defatted soybean meal was used as raw material, pulverized into powder, and water was added at a mass ratio of 1:1 and mixed evenly. Then, a compound bacterial suspension (the concentration of the compound bacterial suspension was 1.0 × 10⁻⁶) was added. 8 The mixture of Bacillus subtilis, Lactobacillus plantarum, and Saccharomyces cerevisiae in a mass ratio of 1:1:1 (total mass of the compound bacterial suspension being 12 wt% of the low-temperature defatted soybean meal) was stirred evenly, sealed with a breathable sealing film, and placed in a sealed environment for fermentation at 38 ℃ for 24 h. After fermentation, the mixture was dried at 50 ℃ for 24 hours to obtain fermented soybean flour.

[0053] (2) Preparation of alcohol-washed soybean powder: The fermented soybean powder prepared in step (1) is mixed with 85% ethanol solution at a mass ratio of 1:9 and stirred for 60 minutes. After filtering to remove ethanol, the resulting filter cake is mixed with 95% ethanol solution and stirred for another 60 minutes. After filtering to remove ethanol, the filter cake is collected, crushed by hand, and the ethanol is evaporated by vacuum rotary evaporation at 50°C. Finally, it is dried at 50°C for 12 hours to obtain alcohol-washed soybean powder. (3) Preparation of isolated protein: The alcohol-washed soybean powder prepared in step (2) was mixed with deionized water at a mass ratio of 1:9, the pH was adjusted to 9.5, stirred for 60 minutes, and centrifuged at 9000 rpm for 30 minutes to remove the precipitate; the pH of the supernatant was adjusted to 4.5, stirred for 60 minutes, and centrifuged at 9000 rpm for 30 minutes to collect the precipitate; the precipitate was crushed, and deionized water at a mass ratio of 1:6 was added again, and the precipitate was collected by centrifugation; the precipitate was added to deionized water at a mass ratio of 1:5, stirred thoroughly, the pH was adjusted to 7.0 until completely dissolved, centrifuged at 9000 rpm for 30 minutes, and the supernatant was collected to obtain the protein neutralization solution; the protein neutralization solution was placed at -20°C for 24 h and freeze-dried under vacuum to prepare isolated protein; (4) Preparation of plant-based coconut juice: Dissolve the isolated protein obtained in step (3) in deionized water to prepare a protein solution, add freshly squeezed coconut meat juice and sucrose, adjust the pH to 7.2 with baking soda, and stir thoroughly until completely dissolved; homogenize the above solution under high pressure of 45 MPa, sterilize with UHT at 138℃ for 12s, cool to 40℃, and fill to obtain plant-based coconut juice. The plant-based coconut juice has a protein mass concentration of 0.6-0.8 wt%, a freshly squeezed coconut meat juice mass concentration of 6.5%, and a sucrose mass concentration of 4%.

[0054] The volatile aldehyde and alcohol content in the protein powder obtained in the above examples was measured to be 328.6 μg / kg, and the volatile aldehyde and alcohol content in the plant-based coconut milk was measured to be 68.1 μg / kg. Compared with the unfermented and unwashed sample (Comparative Example 1), the volatile aldehyde and alcohol content in the protein powder decreased by 93.7%, and the volatile aldehyde and alcohol content in the plant-based coconut milk decreased by 71.8%. The nitrogen solubility index increased by 31%, the emulsifying activity increased by 17%, and the emulsifying stability increased by 126.4% (Table 1). Compared with commercially available coconut milk containing sodium caseinate (Comparative Example 4), the flavor level was similar, but the emulsifying stability was higher, indicating that it is a better alternative to sodium caseinate.

[0055] Example 2 (1) Preparation of fermented soybean flour: Yellow peas are used as raw material, crushed into powder, and water is added at a mass ratio of 1:1 and mixed evenly. Then, a compound bacterial suspension (the concentration of the compound bacterial suspension is 1.0×10⁻⁶) is added. 8 The mixture of Bacillus subtilis, Lactobacillus plantarum, and Saccharomyces cerevisiae in a mass ratio of 1:1:1 (total mass of the compound bacterial suspension being 12 wt% of the low-temperature defatted soybean meal) was stirred evenly, sealed with a breathable sealing film, and placed in a sealed environment for fermentation at 38 ℃ for 24 h. After fermentation, the mixture was dried at 50 ℃ for 24 hours to obtain fermented soybean flour.

[0056] (2) Preparation of alcohol-washed soybean powder: The fermented soybean powder prepared in step (1) is mixed with 85% ethanol solution at a mass ratio of 1:9 and stirred for 60 minutes. After filtering to remove ethanol, the resulting filter cake is mixed with 95% ethanol solution and stirred for another 60 minutes. After filtering to remove ethanol, the filter cake is collected, crushed by hand, and the ethanol is evaporated by vacuum rotary evaporation at 50°C. Finally, it is dried at 50°C for 12 hours to obtain alcohol-washed soybean powder. (3) Preparation of isolated protein: The alcohol-washed soybean powder prepared in step (2) was mixed with deionized water at a mass ratio of 1:9, the pH was adjusted to 9.5, stirred for 60 minutes, and centrifuged at 9000 rpm for 30 minutes to remove the precipitate; the pH of the supernatant was adjusted to 4.5, stirred for 60 minutes, and centrifuged at 9000 rpm for 30 minutes to collect the precipitate; the precipitate was crushed, and deionized water at a mass ratio of 1:6 was added again, and the precipitate was collected by centrifugation; the precipitate was added to deionized water at a mass ratio of 1:5, stirred thoroughly, the pH was adjusted to 7.0 until completely dissolved, centrifuged at 9000 rpm for 30 minutes, and the supernatant was collected to obtain the protein neutralization solution; the protein neutralization solution was placed at -20°C for 24 h and freeze-dried under vacuum to prepare isolated protein; (4) Preparation of plant-based coconut juice: Dissolve the isolated protein obtained in step (3) in deionized water to prepare a protein solution, add freshly squeezed coconut meat juice and sucrose, adjust the pH to 7.2 with baking soda, and stir thoroughly until completely dissolved; homogenize the above solution under high pressure of 45 MPa, sterilize with UHT at 138℃ for 12s, cool to 40℃, and fill to obtain plant-based coconut juice. The plant-based coconut juice has a protein mass concentration of 0.6-0.8 wt%, a freshly squeezed coconut meat juice mass concentration of 6.5%, and a sucrose mass concentration of 4.5%.

[0057] Example 3 (1) Preparation of fermented soybean flour: Low-temperature defatted soybean meal was used as raw material, pulverized into powder, and water was added at a mass ratio of 1:1 and mixed evenly. Then, a compound bacterial suspension (the concentration of the compound bacterial suspension was 1.0 × 10⁻⁶) was added. 8 The mixture of Bacillus subtilis, Lactobacillus plantarum, and Saccharomyces cerevisiae in a mass ratio of 1:2:1 (total mass of the compound bacterial suspension being 10 wt% of the low-temperature defatted soybean meal) was stirred evenly, sealed with a breathable sealing film, and placed in a sealed environment for fermentation at 38 ℃ for 24 h. After fermentation, the mixture was dried at 50 ℃ for 24 hours to obtain fermented soybean flour.

[0058] (2) Preparation of alcohol-washed soybean powder: The fermented soybean powder prepared in step (1) is mixed with 80% ethanol solution at a mass ratio of 1:9 and stirred for 60 minutes. After filtering to remove ethanol, the resulting filter cake is mixed with 92% ethanol solution and stirred for another 60 minutes. After filtering to remove ethanol, the filter cake is collected, crushed by hand, and the ethanol is evaporated by vacuum rotary evaporation at 50°C. Finally, it is dried at 50°C for 12 hours to obtain alcohol-washed soybean powder. (3) Preparation of isolated protein: The alcohol-washed soybean powder prepared in step (2) was mixed with deionized water at a mass ratio of 1:9, the pH was adjusted to 9.5, stirred for 60 minutes, and centrifuged at 9000 rpm for 30 minutes to remove the precipitate; the pH of the supernatant was adjusted to 4.5, stirred for 60 minutes, and centrifuged at 9000 rpm for 30 minutes to collect the precipitate; the precipitate was crushed, and deionized water at a mass ratio of 1:6 was added again, and the precipitate was collected by centrifugation; the precipitate was added to deionized water at a mass ratio of 1:5, stirred thoroughly, the pH was adjusted to 7.0 until completely dissolved, centrifuged at 9000 rpm for 30 minutes, and the supernatant was collected to obtain the protein neutralization solution; the protein neutralization solution was placed at -20°C for 24 h and freeze-dried under vacuum to prepare isolated protein; (4) Preparation of plant-based coconut juice: Dissolve the isolated protein obtained in step (3) in deionized water to prepare a protein solution, add freshly squeezed coconut meat juice and sucrose, adjust the pH to 7.2 with baking soda, and stir thoroughly until completely dissolved; homogenize the above solution under high pressure of 45 MPa, sterilize with UHT at 138℃ for 12s, cool to 40℃, and fill to obtain plant-based coconut juice. The plant-based coconut juice has a protein mass concentration of 0.6-0.8 wt%, a freshly squeezed coconut meat juice mass concentration of 6.5%, and a sucrose mass concentration of 4.5%.

[0059] Example 4 (1) Preparation of fermented soybean flour: Low-temperature defatted soybean meal was used as raw material, pulverized into powder, and water was added at a mass ratio of 1:1 and mixed evenly. Then, a compound bacterial suspension (the concentration of the compound bacterial suspension was 1.0 × 10⁻⁶) was added. 8 The mixture of Bacillus subtilis, Lactobacillus plantarum, and Saccharomyces cerevisiae in a mass ratio of 1:1:1 (total mass of the compound bacterial suspension being 12 wt% of the low-temperature defatted soybean meal) was stirred evenly, sealed with a breathable sealing film, and placed in a sealed environment for fermentation at 38 ℃ for 24 h. After fermentation, the mixture was dried at 50 ℃ for 24 hours to obtain fermented soybean flour.

[0060] (2) Preparation of alcohol-washed soybean powder: The fermented soybean powder prepared in step (1) is mixed with 85% ethanol solution at a mass ratio of 1:9 and stirred for 60 minutes. After filtering to remove ethanol, the resulting filter cake is mixed with 95% ethanol solution and stirred for another 60 minutes. After filtering to remove ethanol, the filter cake is collected, crushed by hand, and the ethanol is evaporated by vacuum rotary evaporation at 50°C. Finally, it is dried at 50°C for 12 hours to obtain alcohol-washed soybean powder. (3) Preparation of isolated protein: The alcohol-washed soybean powder prepared in step (2) was mixed with deionized water at a mass ratio of 1:9, the pH was adjusted to 9.5, stirred for 60 minutes, and centrifuged at 9000 rpm for 30 minutes to remove the precipitate; the pH of the supernatant was adjusted to 4.5, stirred for 60 minutes, and centrifuged at 9000 rpm for 30 minutes to collect the precipitate; the precipitate was crushed, and deionized water at a mass ratio of 1:6 was added again, and the precipitate was collected by centrifugation; the precipitate was added to deionized water at a mass ratio of 1:5, stirred thoroughly, the pH was adjusted to 7.0 until completely dissolved, centrifuged at 9000 rpm for 30 minutes, and the supernatant was collected to obtain the protein neutralization solution; the protein neutralization solution was placed at -20°C for 24 h and freeze-dried under vacuum to prepare isolated protein; (4) Preparation of plant-based coconut juice: Dissolve the isolated protein obtained in step (3) in deionized water to prepare a protein solution, add freshly squeezed coconut meat juice and sucrose, adjust the pH to 7.2 with baking soda, and stir thoroughly until completely dissolved; homogenize the above solution under high pressure of 45 MPa, sterilize with UHT at 138℃ for 12s, cool to 40℃, and fill to obtain plant-based coconut juice. The plant-based coconut juice has a protein mass concentration of 0.6-0.8 wt%, a freshly squeezed coconut meat juice mass concentration of 6.5%, and a sucrose mass concentration of 4.5%.

[0061] Comparative Example 1 Compared with Example 1, the only difference is that steps (1) and (2) are omitted, that is, low-temperature defatted soybean meal is directly used as raw material and crushed into powder. The remaining operation steps remain unchanged from Example 1.

[0062] Comparative Example 2 Compared with Example 1, the only difference is that step (2) of preparing alcohol-washed soybean powder is omitted, while the other steps remain unchanged from Example 1.

[0063] Comparative Example 3 Compared with Example 1, the only difference is that step (1) of preparing fermented soybean flour is omitted, and low-temperature defatted soybean meal is used directly as raw material for the next operation. The operation steps remain unchanged from Example 1.

[0064] Comparative Example 4 Compared with Example 1, the only difference is that steps (1)-(3) are omitted and commercial sodium caseinate is used to replace the isolated protein directly, while the remaining steps remain unchanged from Example 1.

[0065] Comparative Example 5 Compared with Example 1, the only difference is that the concentration of the compound bacterial suspension in step (1) is 1.0 × 10⁻⁶. 8CFU / mL, wherein Bacillus subtilis: Lactobacillus plantarum: Saccharomyces cerevisiae are mixed in a mass ratio of 1:1:0, and the total mass of the compound bacterial suspension is 12wt% of low-temperature defatted soybean meal; the remaining steps are unchanged from Example 1.

[0066] Comparative Example 6 Compared with Example 1, the only difference is that the concentration of the compound bacterial suspension in step (1) is 1.0 × 10⁻⁶. 8 CFU / mL, wherein Bacillus subtilis: Lactobacillus plantarum: Saccharomyces cerevisiae are mixed in a mass ratio of 0:1:0, and the total mass of the compound bacterial suspension is 12wt% of low-temperature defatted soybean meal; the remaining steps are unchanged from Example 1.

[0067] Table 1. Comparison of flavor compound content, nitrogen solubility index, emulsifying activity, and emulsifying stability of protein powder and plant-based coconut milk prepared in the examples and comparative studies.

[0068] As shown in Table 1, this invention can effectively remove most of the undesirable flavor compounds such as aldehydes and alcohols, improve nitrogen solubility index and emulsification properties, and exhibit better volatile flavor indicators when applied to coconut milk.

[0069] The embodiments described above are merely preferred embodiments of the present invention, and not an exhaustive list of all possible implementations of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a sodium caseinate substitute for plant-based coconut milk beverages, characterized in that, The preparation method includes the following steps: (1) Preparation of fermented soybean flour: Soybean flour and water are mixed, a compound bacterial suspension is added, and the mixture is stirred evenly. After sealing, it is fermented at 37-40℃ for 18-24 hours. After fermentation, it is dried to obtain fermented soybean flour. The bacteria in the compound bacterial suspension are Bacillus subtilis CICC20641, Lactobacillus plantarum subsp. plantarum CICC2098, and Saccharomyces cerevisiae CICC1015. The mass ratio of Bacillus subtilis to Lactobacillus plantarum subsp. plantarum is 1:1-2. The mass ratio of Bacillus subtilis to Saccharomyces cerevisiae is 1:1-2. The total amount of bacteria added to the compound bacterial suspension is 1-1.5×10⁻¹⁰ per gram of soybean flour. 7 CFU; (2) Preparation of alcohol-washed soybean powder: The fermented soybean powder prepared in step (1) is mixed with ethanol solution S1 and stirred for 40-80 minutes. After filtering to remove the ethanol, the resulting solid is mixed with ethanol S2 and stirred for 40-80 minutes. After filtering to remove the ethanol, the solid is collected and dried to remove the ethanol, thus obtaining alcohol-washed soybean powder. (3) Preparation of isolated protein: Mix the alcohol-washed soybean powder prepared in step (2) with water, adjust the pH to 9.0-10.5, stir for 30-90 minutes, and centrifuge to remove the precipitate; adjust the pH of the supernatant to 4.0-5.0, stir for 30-90 minutes, centrifuge to collect the precipitate, mix the precipitate with water, centrifuge to collect the precipitate; mix the precipitate with water again, stir thoroughly, adjust the pH to 6.8-7.5 until completely dissolved, centrifuge to collect the supernatant to obtain the protein neutralization solution; freeze-dry the protein neutralization solution under vacuum to prepare the sodium caseinate substitute.

2. The preparation method according to claim 1, characterized in that, The soybean flour mentioned in step (1) is a powder made by crushing defatted soybean meal or soybean seeds as raw materials; the soybean seeds include peas and chickpeas.

3. The preparation method according to claim 1, characterized in that, In step (2), the alcohol content of ethanol solution S1 is 80-85%, and the mixing ratio with fermented soybean powder is 1:5-1:15, w / v; the alcohol content of ethanol solution S2 is 90-95%, and the mixing ratio with fermented soybean powder is 1:3-1:8, w / v.

4. The preparation method according to claim 1, characterized in that, In step (3), the mixing volume of alcohol-washed soybean powder and water is 1:5-1:15; the mixing volume of precipitate and water is 1:5-1:

15.

5. A sodium caseinate substitute for plant-based coconut milk beverages, characterized in that, The sodium caseinate substitute for plant-based coconut milk beverages is prepared by the method according to any one of claims 1-4.

6. The use of the sodium caseinate substitute as described in claim 5 in plant-based coconut milk beverages.

7. The application according to claim 6, characterized in that, The specific application is as follows: Sodium caseinate substitute is dissolved in water to prepare a protein solution. Then, freshly squeezed coconut juice and sucrose are mixed with the protein solution, the pH is adjusted to neutral, and the mixture is stirred until completely dissolved. Then, high-pressure homogenization and UHT sterilization are performed to obtain plant-based coconut juice.

8. The application according to claim 7, characterized in that, Freshly squeezed coconut juice contains 35-40% total solids, 30-35% fat (dry basis), and 3-5% protein (dry basis).

9. The application according to claim 7, characterized in that, The plant-based coconut juice contains 0.6-0.8 wt% sodium caseinate substitute, 6-7 wt% freshly squeezed coconut juice, 4.0-5.5 wt% sucrose, and the remainder is water.

10. The application according to claim 7, characterized in that, The high-pressure homogenization pressure is 40-45 MPa; the UHT sterilization temperature is 135-140℃, and the temperature is maintained for 10-20 seconds.

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