A process for the preparation of a whey carbonated beverage

Abstract

The application discloses a preparation process of whey carbonated beverage, and relates to the technical field of food processing.The whole-chain cooperative process of precise desalination by a bipolar membrane, enzyme protein modification, gradient carbonation and ultrahigh pressure sterilization solves the problems that whey protein acid carbonated system is easy to precipitate, and the stability and taste are difficult to be considered simultaneously.The application has the advantages that the whole-chain cooperative process of precise desalination by a bipolar membrane, enzyme protein modification, composite stable system construction and high-pressure microjet homogenization breaks through the technical limitation of the prior art which only relies on single addition of stabilizers to solve the protein precipitation problem, solves the flocculation, stratification and precipitation core defects of whey protein in the acid carbonated system caused by ion interference, acid-induced denaturation and particle sedimentation, and through multi-dimensional linkage of protein molecular structure modification, system microenvironment regulation and colloid network cooperative protection, the contradiction bottleneck of protein stability improvement and colloid addition amount increase is broken.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a preparation process for a whey carbonated beverage. Background Technology

[0002] With the high-quality development and continuous upgrading of product structure in my country's dairy industry, the market demand and production capacity of cheese products such as cheese and casein have been steadily increasing year by year. As a core by-product in the cheese production process, the output scale of whey has also continued to expand. Whey is rich in high-quality whey protein, lactose, water-soluble vitamins, and various minerals such as calcium and phosphorus. Whey protein contains all eight essential amino acids for the human body, and its amino acid composition is highly compatible with human needs. Its digestibility and absorption rate can reach over 90%, making it a recognized high-quality complete animal protein resource. It also possesses various physiological activities such as immune regulation and antioxidation, giving it extremely high nutritional value and food development value. Existing whey carbonated beverage preparation technologies mainly rely on conventional processes such as adding a single colloidal stabilizer, conventional homogenization, one-time carbonation, and heat sterilization to produce products. These processes aim to solve the precipitation problem of whey protein in acidic carbonation systems and achieve high-value utilization of whey byproducts. However, these technologies have certain drawbacks. First, relying solely on adding a stabilizer cannot fundamentally eliminate the risk of protein instability caused by ion interference and acid-induced denaturation. This leads to a contradiction between improving protein stability and increasing the amount of colloidal stabilizer added, resulting in poor product storage stability and significant batch-to-batch quality variations. Second, conventional one-time carbonation processes are prone to shock denaturation of the protein system and poor foam retention. Traditional heat sterilization can easily cause thermal denaturation of proteins and flavor deterioration. These technologies cannot simultaneously ensure product stability and the refreshing drinking experience of carbonated beverages, resulting in poor adaptability for industrial mass production. Therefore, we propose a whey carbonated beverage preparation process. Summary of the Invention

[0003] The purpose of this invention is to provide a preparation process for whey carbonated beverages.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a preparation process for a whey carbonated beverage, the preparation process comprising the following steps: Step 1: Using whey as raw material, control the initial protein concentration to be 2.0%-6.0%, and successively perform centrifugation defatting and microfiltration clarification treatment to obtain a clear whey liquid with turbidity ≤0.5 NTU; Step 2: Desalting the clarified whey using bipolar membrane electrodialysis, controlling the desalting rate at 40%-70%, to obtain desalted whey; Step 3: Add food-grade transglutaminase to the desalted whey for enzymatic cross-linking modification reaction. After completion, the whey is inactivated to obtain a modified whey with a protein cross-linking degree of 15%-40%. Step 4: Add food-grade compound stabilizer to the modified whey solution, stir until completely hydrated and dissolved, and add flavoring to obtain a homogeneous and stable whey base solution. Step 5: The pH value of the whey base solution is precisely adjusted to 3.8-4.2 using a gradient dripping method, and then homogenized by high-pressure microfluidic jet to obtain a homogenized whey solution with an average particle size ≤200nm. Step 6: Cool the homogenized whey to 0℃-4℃ and perform carbonation treatment using a three-stage partial pressure gradient carbonation process to obtain a carbonated whey with a CO2 volume ratio of 2.0-3.5 times. Step 7: Perform ultra-high pressure cold sterilization on the carbonated whey liquid. After completion, fill the product in a sterile environment to obtain the finished whey carbonated beverage.

[0005] As a further aspect of the present invention: Step one specifically involves using any one of the following raw materials: sweet whey (a byproduct of cheese production), acidic whey (a byproduct of cheese production), or a whey solution composed of whey protein concentrate WPC30-WPC80. The initial protein concentration of the raw material is precisely controlled between 2.0% and 6.0%. Subsequently, a disc centrifuge is used for defatting, controlling the centrifugation speed at 4500 r / min-6500 r / min, the centrifugation temperature at 4℃-10℃, and the centrifugation time at 8 min. After centrifugation for 15 minutes, the upper fat layer and the lower insoluble precipitate are removed to obtain a skimmed whey. The skimmed whey is then clarified by microfiltration using a polyethersulfone microfiltration membrane with a pore size of 0.22μm-0.45μm. The operating pressure is controlled at 0.1MPa-0.3MPa, the feed temperature is 4℃-10℃, and the feed flow rate is 1.0m / s-2.0m / s. After microfiltration, the retained macromolecular impurities, bacteria, and insoluble particles are removed to obtain a clarified whey with a turbidity ≤0.5NTU.

[0006] As a further aspect of the present invention: Step two specifically involves using a two-chamber bipolar membrane electrodialysis device combining a bipolar membrane, a cation exchange membrane, and an anion exchange membrane. The clarified whey obtained in step one is fed into the feed chamber of the electrodialysis device, and food-grade deionized water is fed into the electrode water chamber. The feed temperature in the feed chamber is controlled at 10℃-25℃, the feed flow rate at 1.5cm / s-3.0cm / s, and the operating current density at 10mA / cm². 2 -30mA / cm 2 The voltage across a single membrane is controlled between 0.8V and 1.2V. The conductivity and ion concentration of the feed solution are monitored online throughout the process to control the desalination rate of the whey to 40%-70%. The desalination rate is calculated using the following formula: ; in, For desalination rate, To clarify the initial conductivity of the whey, The real-time conductivity of the whey after desalting is given. After the treatment, the desalted whey has a soluble solids content controlled between 5.0% and 10.0%.

[0007] As a further aspect of the present invention: Step three specifically involves: feeding the desalted whey obtained in step two into a sealed enzymatic hydrolysis reactor equipped with a constant temperature jacket and a sterile stirring device; turning on the stirring and controlling the rotation speed at 60 r / min-120 r / min; precisely adjusting the temperature of the solution to 40℃-55℃ using the constant temperature jacket; adjusting the pH of the solution to 6.0-7.0 using food-grade buffer solution; and then adding food-grade enzyme with an enzyme activity of 100 U / g-200 U / g to the solution. Glutaminase was added at a rate of 8 U / g-25 U / g protein based on the dry weight of the protein in the whey. After the addition was completed, the reaction was carried out in a sealed reactor at a constant temperature for 60-180 minutes, with stable stirring and constant temperature throughout the process. After the reaction was completed, the solution was rapidly heated to 85-90°C and kept at that temperature for 10-15 minutes to complete the enzyme inactivation treatment. Then, the solution was rapidly cooled to 20-25°C using a plate heat exchanger to obtain a modified whey with a protein cross-linking degree of 15%-40%.

[0008] As a further aspect of the present invention: Step four specifically involves: continuously introducing food-grade sterile nitrogen gas into the modified whey obtained in step three to maintain the liquid in an oxygen-free and light-protected environment throughout the process; starting stirring and controlling the speed at 150 r / min-250 r / min; and maintaining the liquid temperature stably at 20℃-30℃. Subsequently, a food-grade composite stabilizer is added to the liquid, with the total amount of the composite stabilizer being 0.15%-0.6% of the total mass of the liquid. The composite stabilizer uses any one of the following two formulations: First... The first group consists of sodium carboxymethyl cellulose, high-ester pectin, and propylene glycol alginate in a mass ratio of 1:2-4:0.5-1.5. The second group consists of sodium carboxymethyl cellulose, citrus fiber, and seaweed powder in a mass ratio of 1:3-5:2-3. After adding the ingredients, the mixture is stirred for 20-40 minutes until the stabilizer is completely hydrated and dissolved, with no visible clumps or undissolved particles. Then, food-grade sweeteners and flavorings are added for basic flavoring according to flavor requirements. After stirring and mixing evenly, a uniform and stable whey base solution is obtained.

[0009] As a further aspect of the present invention: In step five, specifically: under continuous stirring and sterile nitrogen protection, a food-grade acid regulator is added to the whey base obtained in step four by gradient dripping. The acid regulator is an aqueous solution of any one or more of citric acid, malic acid, and lactic acid in any proportion, with a mass concentration of 5%-10%. During the dripping process, an online pH meter is used to continuously monitor the pH value of the liquid, and the pH value of the liquid is finally precisely adjusted to 3.8-4.2. After the dripping is completed, stirring is continued for 10-20 minutes to ensure that the pH value of the system is uniform and without local fluctuations. Then, the acidified whey base is passed into a high-pressure micro-jet homogenizer for homogenization. The homogenization pressure is controlled at 80MPa-150MPa, the feed temperature is 10℃-25℃, and the number of homogenization cycles is 2-4. The temperature of the liquid is controlled not to exceed 30℃ throughout the process by a cooling system. After homogenization, a homogenized whey liquid with an average particle size ≤200nm is obtained.

[0010] As a further aspect of the present invention: In step six, specifically: the homogenized whey obtained in step five is first rapidly cooled to 0℃-4℃ using a plate heat exchanger, and then fed into a sealed carbonation reactor equipped with a constant temperature jacket and a sterile stirring device. After sealing the reactor, a vacuum is drawn until the absolute pressure inside the reactor is -0.08MPa to -0.06MPa, and maintained for 5min-10min to completely remove dissolved oxygen from the system. Subsequently, a three-stage partial pressure gradient carbonation process is used for carbonation treatment. In the first stage, the absolute pressure of food-grade CO2 inside the reactor is controlled at 0.1MPa-0.2MPa, and the stirring speed is 80r / min-120r / min. The process involves three stages: first, pressure adsorption for 5-10 minutes; second, maintaining the absolute CO2 pressure in the reactor at 0.3-0.4 MPa while keeping the stirring speed constant; and third, maintaining the absolute CO2 pressure in the reactor at 0.5-0.6 MPa while keeping the stirring speed constant; and fourth, maintaining the pressure adsorption speed constant for 15-20 minutes. Throughout the process, the temperature of the feed solution is kept stable at 0-4℃ using a constant temperature jacket. After carbonation, the pressure in the reactor is maintained and the solution is allowed to stand for 10-15 minutes. The final product is a carbonated whey solution with a CO2 volume ratio of 2.0-3.5 times under standard conditions at 20℃.

[0011] As a further aspect of the present invention: Step seven specifically involves: feeding the carbonated whey obtained in step six into a food-grade aseptic composite packaging bag under a stable back pressure of 0.4MPa-0.6MPa; after pre-sealing, feeding it into an ultra-high pressure sterilization device; using food-grade filtered water as the pressure transmission medium; controlling the sterilization treatment pressure at 300MPa-600MPa; the treatment temperature at 20℃-30℃; and the pressure holding time at 5min-15min; after sterilization, releasing the pressure at a uniform speed and removing the material; and completing the final sealing in a Class 100 aseptic environment, or directly filling it into aseptic PET bottles in a Class 100 aseptic environment using an aseptic cold filling device; and obtaining the finished whey carbonated beverage after sealing. The finished product is stored away from light throughout the process, and the storage temperature is controlled at 0℃-25℃.

[0012] Compared with the prior art, the beneficial effects of the present invention by adopting the above technical solution are as follows: 1. This invention overcomes the limitations of existing technologies that rely solely on adding a single stabilizer to solve protein precipitation problems through a synergistic process involving precise desalting via bipolar membrane electrodialysis, transglutaminase enzymatic cross-linking modification, construction of a composite stable system, and high-pressure microfluidic homogenization. It fundamentally solves the core defects of whey protein in acidic carbonated systems, such as flocculation, stratification, and precipitation due to ion interference, acid-induced denaturation, and particle sedimentation. Through multi-dimensional linkage of protein molecular structure modification, system microenvironment regulation, and synergistic protection via colloidal networks, it breaks the bottleneck of the contradiction between improving protein stability and increasing colloidal addition, achieving uniform stability of the finished product throughout its entire shelf life. This significantly improves the product's storage stability and batch-to-batch quality consistency, laying a stable quality foundation for the industrial mass production of whey carbonated beverages.

[0013] 2. This invention, through the innovative combination of a three-stage partial pressure gradient carbonation process and an ultra-high pressure cold sterilization process, coupled with the synergistic adaptation of the front-end full-chain stabilization process, solves the core defects of existing technologies, such as conventional one-time carbonation easily causing protein system shock denaturation, large foam and poor foam retention, and traditional heat sterilization easily causing protein thermal denaturation and flavor deterioration. It avoids the common industry problem of adding a large amount of colloid to improve system stability, which leads to a sticky taste and loss of the refreshing and crisp taste of carbonated beverages. While ensuring the long-term stability of the product, it achieves a refreshing and smooth drinking taste, a delicate and lasting foam state, and a full and lasting crisp taste. At the same time, it perfectly adapts to the needs of industrial continuous production, achieving a balance between product nutrition, stability and drinking experience. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the process steps in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the synergistic effect of the core process of carbonated beverages in an embodiment of the present invention. Detailed Implementation

[0015] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0016] Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0017] Please see the appendix Figure 1 -Appendix Figure 2 This invention discloses a preparation process for a whey carbonated beverage, the preparation process comprising the following steps: Step 1: Using whey as raw material, control the initial protein concentration to be 2.0%-6.0%, and successively perform centrifugation defatting and microfiltration clarification treatment to obtain a clear whey liquid with turbidity ≤0.5 NTU; Step 2: Desalting the clarified whey using bipolar membrane electrodialysis, controlling the desalting rate at 40%-70%, to obtain desalted whey; Step 3: Add food-grade transglutaminase to the desalted whey for enzymatic cross-linking modification reaction. After completion, the whey is inactivated to obtain a modified whey with a protein cross-linking degree of 15%-40%. Step 4: Add food-grade compound stabilizer to the modified whey solution, stir until completely hydrated and dissolved, and add flavoring to obtain a homogeneous and stable whey base solution; Step 5: The pH value of the whey base solution is precisely adjusted to 3.8-4.2 using a gradient dripping method, and then homogenized by high-pressure microfluidic jet to obtain a homogenized whey solution with an average particle size ≤200nm. Step 6: Cool the homogenized whey to 0℃-4℃ and perform carbonation treatment using a three-stage partial pressure gradient carbonation process to obtain a carbonated whey with a CO2 volume ratio of 2.0-3.5 times. Step 7: Perform ultra-high pressure cold sterilization on the carbonated whey liquid, and then fill it in a sterile environment to obtain the finished whey carbonated beverage.

[0018] Example 1 This embodiment provides a preparation process for a whey carbonated beverage, the specific steps of which are as follows: Step 1: Pretreatment of whey raw materials: Using sweet whey, a byproduct of cheese production, as raw material, the initial protein concentration of the raw material is precisely controlled at 4.0%. Then, a disc centrifuge is used for defatting. The centrifugation speed is controlled at 5500 r / min, the centrifugation temperature is 6℃, and the centrifugation time is 10 min. After centrifugation, the upper fat layer and the lower insoluble precipitate are removed to obtain defatted whey. The skimmed whey was then clarified by microfiltration using a polyethersulfone microfiltration membrane with a pore size of 0.22 μm. The operating pressure was controlled at 0.2 MPa, the feed temperature at 6 °C, and the feed flow rate at 1.5 m / s. After microfiltration, the trapped macromolecular impurities, bacteria and insoluble particles were removed, and a clarified whey with a turbidity of 0.3 NTU was obtained. Step 2: Precise Desalination via Bipolar Membrane Electrodialysis: A two-chamber bipolar membrane electrodialysis device combining a bipolar membrane, a cation exchange membrane, and an anion exchange membrane is used. The clarified whey obtained in Step 1 is fed into the feed chamber of the electrodialysis device, and food-grade deionized water is fed into the water chamber. The feed temperature in the feed chamber is controlled at 20℃, the feed flow rate at 2.0 cm / s, and the operating current density at 20 mA / cm². 2 The voltage across a single membrane is controlled at 1.0V. The conductivity and ion concentration of the feed solution are monitored online throughout the process. The desalination rate of the whey is controlled at 55%. After treatment, a desalted whey with a soluble solids content of 7.5% is obtained. Step 3: Transglutaminase cross-linking modification: The desalted whey obtained in Step 2 was fed into a sealed enzymatic reaction vessel equipped with a thermostatic jacket and a sterile stirring device. The stirring was turned on and the speed was controlled at 90 r / min. The temperature of the solution was precisely adjusted to 45℃ using the thermostatic jacket. The pH of the solution was adjusted to 6.5 using food-grade phosphate buffer. Then, food-grade transglutaminase with an enzyme activity of 150 U / g was added to the solution. The amount of enzyme added was 15 U / g protein based on the dry weight of the protein in the whey. After the addition was completed, the reaction was carried out in a sealed reaction vessel at a constant temperature for 120 min. Stable stirring and a constant temperature environment were maintained throughout the process. After the reaction was completed, the solution was quickly heated to 85℃ and kept at this temperature for 12 min to complete the enzyme inactivation treatment. Then, the solution was quickly cooled to 22℃ using a plate heat exchanger to obtain a modified whey with a protein cross-linking degree of 28%. Step 4: Construction of the composite stabilization system and basic flavoring: Food-grade sterile nitrogen gas is continuously introduced into the modified whey obtained in Step 3 to maintain the liquid in an anaerobic and light-proof environment throughout the process. Stirring is started and the speed is controlled at 200 r / min. The temperature of the liquid is maintained at 25℃. Then, food-grade composite stabilizer is added to the liquid. The total amount of composite stabilizer added is 0.4% of the total mass of the liquid. The composite stabilizer is composed of sodium carboxymethyl cellulose, high-ester pectin, and propylene glycol alginate in a mass ratio of 1:3:1. After the addition is completed, stirring is continued for 30 minutes until the stabilizer is completely hydrated and dissolved, and there are no visible clumps or undissolved particles. Then, food-grade erythritol and sweet orange flavoring are added for basic flavoring according to the flavor requirements. After stirring and mixing evenly, a homogeneous and stable whey base liquid is obtained. Step 5: Precise pH Control and High-Pressure Microjets Homogenizing: Under continuous stirring and sterile nitrogen protection, a food-grade acid regulator, consisting of an 8% (w / w) citric acid aqueous solution, was added to the whey base obtained in Step 4 using a gradient dropwise addition method. During the dropwise addition, an online pH meter was used to continuously monitor the pH value of the solution, ultimately precisely controlling the pH value to 4.0. After the dropwise addition was completed, stirring was continued for 15 minutes to ensure that the pH value of the system was uniform without local fluctuations. Subsequently, the acidified whey base was passed into a high-pressure microjets homogenizer for homogenization. The homogenization pressure was controlled at 120 MPa, the feed temperature at 20°C, and the number of homogenization cycles was 3. Throughout the process, the temperature of the solution was controlled to not exceed 30°C by a cooling system. After homogenization, a homogenized whey solution with an average particle size of 120 nm was obtained. Step Six: Partial Pressure Gradient Carbonation Treatment: The homogenized whey obtained in Step Five is first rapidly cooled to 2°C using a plate heat exchanger and then fed into a sealed carbonation reactor equipped with a constant temperature jacket and a sterile stirring device. After sealing the reactor, a vacuum is drawn until the absolute pressure inside the reactor is -0.07 MPa, and this is maintained for 8 minutes to completely remove dissolved oxygen from the system. Subsequently, a three-stage partial pressure gradient carbonation process is used for carbonation treatment. In the first stage, the absolute pressure of food-grade CO2 inside the reactor is controlled at 0.15 MPa, the stirring speed is 100 r / min, and the pressure is maintained for 8 minutes for adsorption. The second stage controls the absolute pressure of CO2 inside the reactor to be 0.35 MPa, maintaining the same stirring speed, and adsorbing under pressure for 12 minutes. The third stage controls the absolute pressure of CO2 inside the reactor to be 0.55 MPa, maintains the same stirring speed, and holds the pressure for 18 minutes for adsorption. The temperature of the liquid is kept stable at 2℃ throughout the process by a constant temperature jacket. After the carbonation treatment is completed, the pressure inside the reactor is maintained and allowed to stand for 12 minutes. Finally, a carbonated whey solution with a CO2 volume ratio of 2.8 times under standard conditions at 20℃ is obtained. Step 7, Ultra-high Pressure Cold Sterilization and Aseptic Cold Filling: The carbonated whey obtained in Step 6 is fed into a food-grade aseptic composite packaging bag under a stable back pressure of 0.5 MPa. After pre-sealing, it is sent to an ultra-high pressure sterilization device. Food-grade filtered water is used as the pressure transmission medium. The sterilization pressure is controlled at 400 MPa, the processing temperature at 25℃, and the pressure holding time at 10 minutes. After sterilization, the pressure is released at a uniform speed and the material is removed. The final sealing is completed in a Class 100 aseptic environment to obtain the finished whey carbonated beverage. The finished product is stored in the dark throughout the process, and the storage temperature is controlled at 25℃.

[0019] Example 2 This embodiment provides a preparation process for a whey carbonated beverage, which differs from Embodiment 1 only in that: Step 1: Pretreatment of whey raw materials: Using whey solution compounded with whey protein concentrate WPC60 as raw material, the initial protein concentration is controlled at 2.5%, the centrifugation speed is 4800 r / min, the centrifugation temperature is 8℃, the centrifugation time is 12 min, the microfiltration membrane pore size is 0.45 μm, the operating pressure is 0.15 MPa, the feed temperature is 8℃, and the feed flow rate is 1.2 m / s, finally obtaining a clear whey liquid with a turbidity of 0.4 NTU; Step 2: Precise desalination via bipolar membrane electrodialysis: The feed temperature in the feed chamber is controlled at 15℃, the feed flow rate at 1.8 cm / s, and the operating current density at 15 mA / cm². 2 The voltage across a single membrane is controlled at 0.9V, and the desalination rate is controlled at 45%. After the treatment, a desalted whey with a soluble solids content of 6.0% is obtained. Step 3: Transglutaminase enzymatic cross-linking modification: The stirring speed was 70 r / min, the temperature of the solution was adjusted to 50℃, the pH value was adjusted to 6.8, the transglutaminase activity was 120 U / g, the amount added was 10 U / g protein, the reaction time was 90 min, and the inactivation condition was 90℃ for 10 min, finally obtaining a modified whey solution with a protein cross-linking degree of 20%. Step 4: Construction of the composite stabilization system and basic flavoring: The stirring speed is 180 r / min, the liquid temperature is 22℃, the total amount of composite stabilizer added is 0.25%, the composite stabilizer is composed of sodium carboxymethyl cellulose, citrus fiber and seaweed powder in a mass ratio of 1:4:2.5, the stirring time is 25 min, food-grade xylitol and lemon flavoring are added for flavoring, and whey base liquid is obtained; Step 5: Precise pH control and high-pressure microfluidic homogenization: The acid regulator is a 6% (w / w) malic acid aqueous solution. The final pH value is controlled to 3.9. After adding the solution dropwise, stir for 12 minutes. The homogenization pressure is 100 MPa, the feed temperature is 15℃, and the homogenization cycle is 2 times. Finally, a homogenized whey with an average particle size of 160 nm is obtained. Step 6: Partial pressure gradient carbonation treatment: Cool the homogenized whey to 3°C, evacuate to an absolute pressure of -0.065 MPa inside the vessel, and maintain for 6 minutes; The absolute pressure of the first-stage CO2 adsorption is 0.12 MPa, and the pressure is maintained for 6 minutes. The absolute pressure of the second-stage CO2 adsorption is 0.32 MPa, and the adsorption is maintained at this pressure for 10 minutes. The third-stage CO2 absolute pressure was 0.52 MPa, and the pressure adsorption was maintained for 16 minutes. The temperature of the feed solution was kept stable at 3℃ throughout the process, and finally a carbonated whey solution with a CO2 volume ratio of 2.5 times was obtained. Step 7, Ultra-high pressure cold sterilization and aseptic cold filling: The stable back pressure is 0.45MPa, the sterilization treatment pressure is 350MPa, the treatment temperature is 22℃, the pressure holding time is 12min, after sterilization, the product is filled into aseptic PET bottles using aseptic cold filling equipment in a Class 100 aseptic environment, and then sealed to obtain the finished product. The storage temperature of the finished product is controlled at 4℃.

[0020] Comparative Example This comparative example provides a preparation process for a whey carbonated beverage, which is a conventional method for preparing whey carbonated beverages in the prior art. The specific steps are as follows: Step 1: Raw material pretreatment: Using the same sweet whey as in Example 1 as the raw material, the initial protein concentration was controlled at 4.0%. The same centrifugation defatting and microfiltration clarification treatment as in Example 1 was used to obtain a clarified whey liquid. Step 2, Construction of a stable system: Add a food-grade composite stabilizer to the clarified whey liquid. The total amount of the composite stabilizer is 1.2%, and it is composed of sodium carboxymethyl cellulose and high-ester pectin in a mass ratio of 1:3. Stir until completely dissolved, and add erythritol and sweet orange flavoring, which are the same as in Example 1, to obtain the whey base liquid. Step 3, pH adjustment and homogenization: The pH of the whey base solution is adjusted to 4.0 by one-time dropwise addition. After stirring evenly, it is homogenized using a conventional high-pressure homogenizer at a pressure of 40 MPa and a temperature of 60°C. The homogenization is repeated twice to obtain a homogenized whey solution. Step 4, Carbonation treatment: Cool the homogenized whey to 4°C and send it into the carbonation reactor. Introduce CO2 all at once until the absolute pressure inside the reactor is 0.6 MPa. Stir at 100 r / min and maintain the pressure for 30 min to obtain the carbonated whey. Step 5, Sterilization and Filling: The carbonated whey liquid is pasteurized at 85℃ for 15 minutes. After sterilization, it is hot-filled, sealed and naturally cooled to room temperature to obtain the finished whey carbonated beverage.

[0021] Performance test results and comparative analysis The whey carbonated beverages prepared in Examples 1, 2, and the comparative example were subjected to performance testing according to the aforementioned unified testing method. The test results are shown in Table 1 below: Table 1 shows the performance test results of each embodiment and comparative example:

[0022] Table 1: Performance Test Results of Examples and Comparative Examples As can be seen from the test results in Table 1, the whey carbonated beverages prepared in Examples 1 and 2 of this invention are significantly superior to the conventional processes of the prior art in all performance indicators. The specific analysis is as follows: Protein stability and shelf-life performance: The initial protein precipitation rate in the embodiments of this invention was less than 0.12%, and the protein precipitation rate remained below 0.2% after 6 months of storage at 25°C, with no stratification, flocculation, or precipitation. In contrast, the initial precipitation rate in the comparative example reached 0.42%, and the precipitation rate was as high as 1.87% after 6 months of storage, exhibiting severe stratification and precipitation. This indicates that the present invention, through a full-chain synergistic process of precise desalting via bipolar membrane electrodialysis, transglutaminase enzymatic cross-linking modification, construction of a composite stable system, and high-pressure microfluidic homogenization, addresses the core problem of whey protein's susceptibility to denaturation and precipitation in acidic carbonic acid systems from multiple dimensions, including protein molecular structure modification, system ionic strength regulation, colloidal network synergistic protection, and particle ultrafine processing. This significantly improves the shelf-life stability of the product and breaks through the bottleneck of existing technologies that rely on the addition of large amounts of colloids for stability improvement.

[0023] Foam stability and drinking experience: The foam half-life of the embodiments of this invention all exceeded 190s, and the sensory scores were all above 90 points, while the foam half-life of the comparative example was only 65s, and the sensory score was only 71 points. This shows that the three-stage partial pressure gradient carbonation process adopted in this invention avoids the impact of conventional one-time high-pressure carbonation on the protein system, forming a delicate and uniform bubble core, which greatly improves foam stability and foam retention. At the same time, combined with the ultra-high pressure cold sterilization process, it avoids the flavor deterioration caused by heat sterilization. Under the premise of significantly reducing the amount of colloid added, it achieves a refreshing and smooth taste, a full and lasting carbonation, and a harmonious flavor, perfectly balancing product stability and drinking experience.

[0024] System uniformity: The average particle size of the particles in the embodiments of the present invention is less than 200 nm, which is much lower than 850 nm in the comparative example. This indicates that the high-pressure micro-jet homogenization process of the present invention, combined with the protein modification process at the front end, has achieved ultrafine particle processing of the system, further reduced the particle settling rate, improved the long-term stability of the system, and laid a solid quality foundation for the industrial mass production of the product.

[0025] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A preparation process for a whey carbonated beverage, characterized in that, The preparation process includes the following steps: Step 1: Using whey as raw material, control the initial protein concentration to be 2.0%-6.0%, and successively perform centrifugation defatting and microfiltration clarification treatment to obtain a clear whey liquid with turbidity ≤0.5 NTU; Step 2: Desalting the clarified whey using bipolar membrane electrodialysis, controlling the desalting rate at 40%-70%, to obtain desalted whey; Step 3: Add food-grade transglutaminase to the desalted whey for enzymatic cross-linking modification reaction. After completion, the whey is inactivated to obtain a modified whey with a protein cross-linking degree of 15%-40%. Step 4: Add food-grade compound stabilizer to the modified whey solution, stir until completely hydrated and dissolved, and add flavoring to obtain a homogeneous and stable whey base solution; Step 5: The pH value of the whey base solution is precisely adjusted to 3.8-4.2 using a gradient dripping method, and then homogenized by high-pressure microfluidic jet to obtain a homogenized whey solution with an average particle size ≤200nm. Step 6: Cool the homogenized whey to 0℃-4℃ and perform carbonation treatment using a three-stage partial pressure gradient carbonation process to obtain a carbonated whey with a CO2 volume ratio of 2.0-3.5 times. Step 7: Perform ultra-high pressure cold sterilization on the carbonated whey liquid, and then fill it in a sterile environment to obtain the finished whey carbonated beverage.

2. The preparation process of a whey carbonated beverage according to claim 1, characterized in that: In step one, specifically, the following steps are taken: using any one of the following raw materials as a byproduct of cheese production—sweet whey, sour whey, or a whey solution composed of whey protein concentrate WPC30-WPC80—the initial protein concentration of the raw material is precisely controlled between 2.0% and 6.0%. Then, a disc centrifuge is used for defatting, controlling the centrifugation speed at 4500 r / min-6500 r / min, the centrifugation temperature at 4℃-10℃, and the centrifugation time at 8 min-15 min. After centrifugation, the upper fat layer and the lower insoluble precipitate are removed to obtain a defatted whey. The defatted whey is then clarified by microfiltration using a polyethersulfone microfiltration membrane with a pore size of 0.22μm-0.45μm. The operating pressure is controlled at 0.1MPa-0.3MPa, the feed temperature is 4℃-10℃, and the feed flow rate is 1.0m / s-2.0m / s. After microfiltration, the retained macromolecular impurities, bacteria, and insoluble particles are removed to obtain a clarified whey with a turbidity ≤0.5NTU.

3. The preparation process of a whey carbonated beverage according to claim 1, characterized in that: Step two specifically involves using a two-chamber bipolar membrane electrodialysis device combining a bipolar membrane, a cation exchange membrane, and an anion exchange membrane. The clarified whey obtained in step one is fed into the feed chamber of the electrodialysis device, while food-grade deionized water is fed into the electrode water chamber. The feed temperature in the feed chamber is controlled at 10℃-25℃, the feed flow rate at 1.5cm / s-3.0cm / s, and the operating current density at 10mA / cm². 2 -30mA / cm 2 The voltage across a single membrane is controlled between 0.8V and 1.2V. The conductivity and ion concentration of the feed solution are monitored online throughout the process to control the desalination rate of the whey to 40%-70%. The desalination rate is calculated using the following formula: ； in, For desalination rate, To clarify the initial conductivity of the whey, The real-time conductivity of the whey after desalting is given. After the treatment, the desalted whey has a soluble solids content controlled between 5.0% and 10.0%.

4. The preparation process of a whey carbonated beverage according to claim 1, characterized in that: Step three specifically involves: The desalted whey obtained in step two is fed into a sealed enzymatic hydrolysis reactor equipped with a thermostatic jacket and a sterile stirring device. Stirring is started and the rotation speed is controlled at 60-120 rpm. The temperature of the solution is precisely adjusted to 40-55°C using the thermostatic jacket. The pH of the solution is adjusted to 6.0-7.0 using food-grade buffer solution. Subsequently, food-grade transglutaminase with an enzyme activity of 100-200 U / g is added to the solution. The amount of enzyme added is 8 U / g-25 U / g protein based on the dry weight of protein in the whey. After the addition is completed, the reaction is carried out in a sealed reaction vessel at a constant temperature for 60 min-180 min, with stable stirring and constant temperature maintained throughout the process. After the reaction is completed, the solution is quickly heated to 85℃-90℃ and kept at this temperature for 10 min-15 min to complete the enzyme inactivation treatment. Then, it is quickly cooled to 20℃-25℃ through a plate heat exchanger to obtain a modified whey with a protein cross-linking degree of 15%-40%.

5. The preparation process of a whey carbonated beverage according to claim 1, characterized in that: In step four, specifically: food-grade sterile nitrogen gas is continuously introduced into the modified whey solution obtained in step three to maintain the solution in an oxygen-free and light-protected environment throughout the process; stirring is started and the speed is controlled at 150 r / min-250 r / min; the temperature of the solution is stably maintained at 20℃-30℃; then, a food-grade composite stabilizer is added to the solution, with the total amount of composite stabilizer added being 0.15%-0.6% based on the total mass of the solution. The composite stabilizer uses either of the following two formulations: the first formulation is carboxymethyl cellulose. The first group consists of sodium vitamin, high-ester pectin, and propylene glycol alginate in a mass ratio of 1:2-4:0.5-1.

5. The second group consists of sodium carboxymethyl cellulose, citrus fiber, and seaweed powder in a mass ratio of 1:3-5:2-3. After adding the ingredients, the mixture is stirred for 20-40 minutes until the stabilizer is completely hydrated and dissolved, with no visible clumps or undissolved particles. Then, food-grade sweeteners and flavorings are added for basic flavoring according to flavor requirements. After stirring and mixing evenly, a uniform and stable whey base is obtained.

6. The preparation process of a whey carbonated beverage according to claim 1, characterized in that: In step five, specifically: under continuous stirring and sterile nitrogen protection, a food-grade acid regulator is added to the whey base obtained in step four using a gradient dropwise method. The acid regulator is an aqueous solution of any one or more of citric acid, malic acid, and lactic acid in any proportion, with a mass concentration of 5%-10%. During the dropwise addition, an online pH meter is used to continuously monitor the pH value of the solution, and the pH value of the solution is finally precisely adjusted to 3.8-4.

2. After the dropwise addition is completed, stirring is continued for 10-20 minutes to ensure that the pH value of the system is uniform and without local fluctuations. Then, the acidified whey base is passed into a high-pressure micro-jet homogenizer for homogenization. The homogenization pressure is controlled at 80MPa-150MPa, the feed temperature is 10℃-25℃, and the number of homogenization cycles is 2-4. Throughout the process, the temperature of the solution is controlled not to exceed 30℃ through a cooling system. After homogenization, a homogenized whey solution with an average particle size ≤200nm is obtained.

7. The preparation process of a whey carbonated beverage according to claim 1, characterized in that: In step six, specifically: the homogenized whey obtained in step five is first rapidly cooled to 0℃-4℃ using a plate heat exchanger, and then fed into a sealed carbonation reactor equipped with a constant temperature jacket and a sterile stirring device. After sealing the reactor, a vacuum is drawn until the absolute pressure inside the reactor is -0.08MPa to -0.06MPa, and maintained for 5-10 minutes to completely remove dissolved oxygen from the system. Subsequently, a three-stage partial pressure gradient carbonation process is used for carbonation treatment. In the first stage, the absolute pressure of food-grade CO2 inside the reactor is controlled at 0.1MPa-0.2MPa, the stirring speed is 80r / min-120r / min, and the pressure adsorption is maintained for 5 minutes. The second stage controls the absolute CO2 pressure inside the reactor to be 0.3MPa-0.4MPa for 10-10 minutes, maintaining the same stirring speed, and adsorbing under pressure for 10-15 minutes. The third stage controls the absolute CO2 pressure inside the reactor to be 0.5MPa-0.6MPa, maintaining the same stirring speed, and adsorbing under pressure for 15-20 minutes. Throughout the process, the temperature of the feed solution is kept stable at 0℃-4℃ by a constant temperature jacket. After the carbonation treatment is completed, the pressure inside the reactor is maintained and allowed to stand for 10-15 minutes. Finally, a carbonated whey solution with a CO2 volume ratio of 2.0-3.5 times under standard conditions at 20℃ is obtained.

8. The preparation process of a whey carbonated beverage according to claim 1, characterized in that: In the aforementioned steps, step seven specifically involves: feeding the carbonated whey obtained in step six into a food-grade aseptic composite packaging bag under a stable back pressure of 0.4MPa-0.6MPa; after pre-sealing, feeding it into an ultra-high pressure sterilization device; using food-grade filtered water as the pressure transmission medium; controlling the sterilization pressure at 300MPa-600MPa; the processing temperature at 20℃-30℃; and the pressure holding time at 5min-15min; after sterilization, releasing the pressure at a uniform rate and removing the material; and completing the final sealing in a Class 100 aseptic environment, or directly filling it into aseptic PET bottles in a Class 100 aseptic environment using aseptic cold filling equipment; and obtaining the finished whey carbonated beverage after sealing. The finished product is stored away from light throughout the process, with the storage temperature controlled at 0℃-25℃.

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