A dairy processing technology and dairy products based on continuous hydraulic cavitation

Abstract

This invention relates to a dairy processing technology and dairy products based on continuous hydraulic cavitation. The invention provides a dairy processing technology based on continuous hydraulic cavitation, comprising the following steps: (1) feeding the emulsion into a hydraulic cavitation reactor for continuous hydraulic cavitation pretreatment; (2) cooling the pretreated emulsion to remove excess milk fat, completing the defatting process; (3) ultrafiltration membrane concentration: concentrating the defatted emulsion through an ultrafiltration membrane to obtain lactose-free skimmed milk; (4) drying the lactose-free skimmed milk. This invention uses hydraulic cavitation technology to pretreat milk raw materials, completing the defatting and sterilization steps, and achieving a reduction in the average particle size of protein molecules, lactose, and ash content under low-temperature conditions, solving the problems of complex processing procedures, low product yield, and unsatisfactory product quality in traditional production technologies.

Description

Technical Field

[0001] This invention belongs to the field of dairy processing technology, specifically relating to a dairy processing technology based on continuous hydraulic cavitation, and dairy products obtained based on the aforementioned processing technology. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] With the continuous improvement of living standards, people have gradually recognized the importance of protein to the human body. Among the many protein sources, milk and its processed products have become the primary choice for protein supplementation due to their rich protein content, diverse health-promoting active protein components, and reasonable protein ratio. In addition, with the popularization of the concept of a healthy and balanced lifestyle, the demand for low-fat dairy products is increasing. Concentrated milk protein is widely used due to its advantages such as low fat, high protein, easy storage, and easy gelation.

[0004] There are three main problems in the production process of concentrated milk protein:

[0005] First, the processing procedure is complex. The current process of processing concentrated milk protein mainly involves putting skimmed milk into a pasteurizer for sterilization, then ultrafiltration and percolation of the processed product, followed by evaporation to further remove moisture, and then drying in a dryer to obtain concentrated milk protein powder product.

[0006] Secondly, the product yield is low. Because milk has a high viscosity, and as the water content decreases during the processing, the casein molecules in the milk will connect with each other to form larger protein molecules, which increases the viscosity. This is not conducive to subsequent drying. Studies have shown that if the viscosity can be reduced by 20% before spray drying, the yield of concentrated milk protein can be increased by 15%.

[0007] Third, the quality of the product is not ideal. Due to the excessively large protein particle size, the protein distribution in the emulsion is not uniform and the stability is not high. In addition, a large amount of calcium and magnesium phosphates and citrates are mixed in the casein, forming large molecules that are difficult to remove. These salts are not conducive to the absorption and utilization of protein.

[0008] The main solution to the above problems is to replace the ultrafiltration process with a filter membrane that can pass through smaller particles. This can reduce the particle size of concentrated milk protein to some extent, but it also sacrifices some yield and cannot fundamentally solve the problems of complex production process, low output and poor product quality.

[0009] Given the three disadvantages of concentrated milk protein products produced by the traditional "ultrafiltration membrane concentration + high temperature spray drying" technology—high energy consumption, heat-sensitive protein denaturation, and high lactose content—exploring a simpler process has become the development direction for concentrated milk protein technology. Summary of the Invention

[0010] This invention addresses the shortcomings of existing protein product manufacturing processes by proposing a hydraulic cavitation pretreatment process for concentrated milk protein that offers superior pretreatment performance, high efficiency, and the ability to reduce the particle size of concentrated milk protein.

[0011] In a first aspect, the present invention provides a dairy processing technology based on continuous hydraulic cavitation, wherein the processing technology is characterized by defatting the dairy product through hydraulic cavitation and then concentrating the protein in the defatted dairy product through ultrafiltration.

[0012] Taking raw milk processing as an example, this invention processes milk raw materials using a continuous rotating hydraulic cavitation reactor. The high-speed rotation first achieves milk fat separation. In addition to milk fat separation, this invention also discovers that hydraulic cavitation pretreatment can sterilize and assist in protein concentration. The specific principle is as follows: During the hydraulic cavitation treatment of milk, a large number of cavitation bubbles are generated. When these bubbles collapse, a large amount of energy is generated, which in turn produces high-speed microjets that impact protein molecules and bacteria in the milk. Furthermore, under the impact of the microjets, the -[CN-CN]- and -[CN-WP]- bonds of the protein molecules open, disrupting the protein molecular structure. Ash (calcium and magnesium phosphates and citrates) and lactose bound to the protein are released from the protein molecules. Finally, hydraulic cavitation pretreatment can also break the adhesion of protein micelles, refine the average particle size of protein molecules, and reduce the viscosity of the protein solution. Therefore, the pretreatment of hydraulic cavitation can achieve the classification of milk fat, protein, ash and lactose components in dairy products. In this way, the protein in the defatted protein solution can be easily separated from components such as lactose by means of ultrafiltration, laying the foundation for the improvement of subsequent product yield.

[0013] In addition, the local hot spots generated by cavitation do not significantly raise the temperature of the milk. The local high temperatures formed during hydraulic cavitation are rapidly reduced by strong convective heat transfer, thus achieving defatting and sterilization of the milk at a lower temperature. Studies have shown that below 80°C, protein solubility increases with increasing temperature, while above 80°C, protein molecules will form peptide bonds and recombine into larger molecules, reducing solubility. This solves the problem of incomplete sterilization caused by low-temperature pasteurization. Unlike high-temperature pasteurization (heating milk to 75–90°C for 10–15 seconds), continuous hydraulic cavitation technology can sterilize the milk concentrate at a lower temperature (below 70°C) and in a very short time (within 2–3 seconds), preserving as much of the milk's nutrients and flavor as possible. Furthermore, the lower temperature environment reduces the likelihood of small protein molecules combining to form larger molecules, thereby increasing protein solubility.

[0014] In a second aspect, the present invention provides a dairy product prepared by the dairy processing process based on continuous hydraulic cavitation as described in the first aspect.

[0015] Currently, the main method for removing lactose from dairy products is membrane separation technology, which combines ultrafiltration and nanofiltration. While membrane separation technology effectively preserves the flavor of dairy products, it suffers from long production cycles and high costs. The process provided by this invention simultaneously achieves defatting, sterilization, and reduction of the average molecular weight of proteins under low-temperature conditions through hydraulic cavitation. This provides a more thorough sterilization effect compared to existing technologies, significantly reducing the processing difficulty of dairy products. Furthermore, it effectively preserves all bovine milk proteins, including heat-sensitive whey proteins, ensuring the flavor and nutritional components of the dairy products. Attached Figure Description

[0016] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0017] Figure 1 This is a flowchart of the process for pretreating concentrated milk protein using hydraulic cavitation according to the present invention.

[0018] Figure 2 This is a SEM electron microscope image showing the inactivation effect of the pretreatment process of this invention on Escherichia coli.

[0019] (a) is a 500 nm SEM image of Escherichia coli before treatment;

[0020] (b) is a 500 nm SEM image of treated Escherichia coli. Detailed Implementation

[0021] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] As described in the background section, the purpose of this invention is to meet the demand for concentrated milk protein raw materials from dairy product and high-protein beverage processing enterprises, thereby satisfying the nutritional needs of high-protein foods. Using the various nutritional components of raw milk as a benchmark, hydraulic cavitation is employed to pretreat the milk, significantly reducing the fat, lactose, and water content while retaining all milk proteins (including heat-sensitive whey protein), producing concentrated milk protein powder, which is then packaged, frozen, and stored for later use. The concentrated milk protein products (including protein concentrate or protein concentrate powder) prepared by the method of this invention are expected to have wider applications in the food industry as food ingredients, particularly meeting the needs of lactose-intolerant and diabetic individuals.

[0024] In a first aspect, the present invention provides a dairy processing technology based on continuous hydraulic cavitation, wherein the processing technology is characterized by defatting the dairy product through hydraulic cavitation and then concentrating the protein in the defatted dairy product through ultrafiltration.

[0025] The term "dairy product" refers to the milk of mammals, including but not limited to cow's milk, buffalo milk, goat's milk, yak milk, camel milk, and donkey milk; furthermore, in one feasible embodiment of the present invention, the dairy product is cow's milk, or raw cow's milk.

[0026] In the processing technology described in the first aspect, the ultrafiltration concentration is achieved through an ultrafiltration membrane; preferably, the specific steps of the processing technology are as follows:

[0027] (1) The dairy products are transported to a hydraulic cavitation reactor for continuous hydraulic cavitation pretreatment;

[0028] (2) After pretreatment, the dairy product is cooled and the milk fat is removed to obtain defatted emulsion and milk fat;

[0029] (3) The defatted emulsion is concentrated by passing it through an ultrafiltration membrane to obtain lactose-free defatted milk, wherein the ultrafiltration membrane has a molecular weight of 2000-4000.

[0030] In step (1), the hydraulic cavitation reactor is a rotor-type hydraulic cavitation reactor with a rotation speed of 2500–4000 rpm; the flow rate of the dairy product entering the hydraulic cavitation reactor is 0.1–0.5 m³ / min. 3 / h.

[0031] Preferably, the rotational speed is 3200-3800 rpm, more preferably 3400-3600 rpm.

[0032] Preferably, the flow rate is 0.15–0.4 m³ / s. 3 / h, more preferably 0.2 to 0.3m 3 / h.

[0033] Under the above-mentioned rotational speed conditions, the cavitation instantaneous heat generation heats the working fluid, and the processing temperature of dairy products can reach 50-75°C; preferably 55-70°C, and more preferably 60-65°C.

[0034] In step (2), the specific steps for removing milk fat are as follows: after passing through the hydraulic cavitation equipment, the milk fat and the defatted emulsion are separated into layers, with the milk fat floating on the surface of the emulsion. The defatted emulsion is first discharged from the valve at the bottom of the hydraulic cavitation equipment, and then the milk fat is discharged, thereby achieving the separation of milk fat.

[0035] In step (3), the molecular weight of the ultrafiltration membrane is preferably 2000-3000, more preferably 2000-2500.

[0036] In step (3), the defatted emulsion is concentrated by ultrafiltration membrane, and the molecular weight of ultrafiltration membrane, the outlet pressure of retentate and the concentration ratio are controlled to obtain lactose-free defatted milk; the outlet pressure of retentate is controlled at 2 to 4 bar, preferably 3 to 4 bar, more preferably 3.5 to 4 bar; the concentration ratio is 24 to 33.5, preferably 30 to 33.5, more preferably 33.5.

[0037] The preparation method of the first aspect mentioned above further includes a step of drying the lactose-free skim milk, preferably by spray drying. In a specific embodiment of the present invention, the lactose-free skim milk is pumped into a spray dryer under high pressure by a diaphragm pump, forming a mist-like droplet, which then flows in parallel with the hot air in the spray dryer. Most of the dried powder particles are collected from the discharge port at the bottom of the dryer, and the waste gas and its fine powder are separated by a cyclone separator. The waste gas is discharged by an exhaust fan, and the fine powder is collected by a powder-collecting cylinder located at the lower end of the cyclone separator. The diaphragm pump, spray dryer, and cyclone separator are all existing equipment.

[0038] After atomization, the surface area of ​​lactose-free skim milk increases significantly. In a hot air stream, 95-98% of the water can evaporate within 10-20 seconds, producing uniformly sized, free-flowing spherical particles (milk protein concentrate), i.e., concentrated milk protein product. These spherical particles are then rapidly cooled to a temperature not exceeding 7°C, preferably 0-7°C, and more preferably 0-4°C for storage.

[0039] In a second aspect, the present invention provides dairy processed products prepared by the dairy processing process based on continuous hydraulic cavitation as described in the first aspect.

[0040] Based on the processing technology provided in the first aspect, milk can be processed into three processed products: milk fat, lactose-free skim milk, and lactose. Among these, lactose-free skim milk is a high-quality milk protein product. The protein, lactose, and fat content of the lactose-free skim milk has been determined to be:

[0041] The protein content is 8-10%, preferably 9-10%, and more preferably 9.5-10%;

[0042] The lactose content is 0.25-0.5%, preferably 0.25-0.35%, and more preferably 0.25-0.3%.

[0043] The fat content is 0.15-0.20%, preferably 0.15-0.18%, and more preferably 0.15-0.17%.

[0044] Milk fat and lactose can also be used as high-quality raw materials in other fields. For example, milk fat can be used in the preparation of butter, and lactose can be used as a fermentation substrate for microorganisms.

[0045] Therefore, preferably, the specific examples of the dairy processed products are milk protein, butter, etc.

[0046] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples. The raw material used in the following embodiments is raw milk. All raw milk used conforms to GB-19301-2010.

[0047] Example 1

[0048] The specific process for concentrating 2000kg of raw milk is as follows:

[0049] 1) Raw milk is passed through a hydraulic cavitation reactor;

[0050] 2) The parameters for the hydraulic cavitation pretreatment process are: temperature 65℃, flow rate 0.252 m³ / h. 3 / h, speed 3600rpm;

[0051] 3) The obtained milk is temporarily stored in a jacketed storage tank; excess milk fat is removed, and the milk is cooled and temporarily stored.

[0052] 4) Ultrafiltration membrane (UF membrane) concentration: The material is concentrated by passing it through an ultrafiltration membrane with a molecular weight of 2000. The outlet pressure of the retentate is controlled at 4.0 bar, and the concentration ratio is 33.5, to obtain lactose-free skim milk with a protein content of 9.5%, a lactose content of 0.3%, and a fat content of 0.16%.

[0053] 5) The lactose-free skim milk is fed into a spray dryer. The lactose-free skim milk is input under high pressure via a diaphragm pump, spraying out as atomized droplets. These droplets then descend in parallel with hot air. Most of the powder particles are collected at the bottom discharge port of the dryer. The waste gas and fine powder are separated by a cyclone separator. The waste gas is discharged by an exhaust fan, and the powder is collected by a powder collection tube located at the lower end of the cyclone separator. After atomization, the surface area of ​​the lactose-free skim milk is greatly increased. In the hot air stream, 98% of the moisture can evaporate within 10-20 seconds, producing uniformly sized, free-flowing spherical particles.

[0054] 6) Cooling and storage: The obtained milk is rapidly cooled to ≤7℃ and stored in a jacketed tank with ice water.

[0055] 8) Filling and packaging;

[0056] 9) Freezing: Store the packaged milk protein concentrate frozen at ≤-22℃;

[0057] 10) Finished product inspection.

[0058] The test results of the spherical particulate products obtained in this embodiment are as follows: lactose content is 1.2%; protein content is 33%; fat content is 0.8%; calcium content is 455 mg / kg; β-lactoglobulin content is 14 mg / mL; lactoferrin content is 585 ug / mL; α-lactoglobulin content is 5.90 mg / mL; immunoglobulin IgG content is 898 mg / L. The viscosity of the obtained protein sample, measured at a shear rate of 100 times per second, is 93.78 mPa·s. The average particle size of the concentrated milk protein solution is 30.85 ± 1.76 μm. 10 D 50 D 90 The values ​​were 9.10±0.24um, 18.92±0.22um, and 65.55±3.95um, respectively.

[0059] Example 2

[0060] The specific process for concentrating 2000kg of raw milk is as follows:

[0061] 1) Raw milk is passed through a hydraulic cavitation reactor;

[0062] 2) The parameters for the hydraulic cavitation pretreatment process are: temperature 80℃, flow rate 0.252m³ / h. 3 / h, speed 3400rpm;

[0063] 3) The obtained milk is temporarily stored in a jacketed storage tank; excess milk fat is removed, and the milk is cooled and temporarily stored.

[0064] 4) Ultrafiltration membrane (UF membrane) concentration: The material is concentrated by passing it through an ultrafiltration membrane with a molecular weight of 2000. The outlet pressure of the retentate is controlled at 4.0 bar, and the concentration ratio is 33.5, to obtain lactose-free skim milk with a protein content of 9.5%, a lactose content of 0.3%, and a fat content of 0.16%.

[0065] 5) The lactose-free skim milk is fed into a spray dryer. The lactose-free skim milk is input under high pressure via a diaphragm pump, spraying out as atomized droplets. These droplets then descend in parallel with hot air. Most of the powder particles are collected at the bottom discharge port of the dryer. The waste gas and fine powder are separated by a cyclone separator. The waste gas is discharged by an exhaust fan, and the powder is collected by a powder collection tube located at the lower end of the cyclone separator. After atomization, the surface area of ​​the lactose-free skim milk is greatly increased. In the hot air stream, 98% of the moisture can evaporate within 10-20 seconds, producing uniformly sized, free-flowing spherical particles.

[0066] 6) Cooling and storage: The obtained milk is rapidly cooled to ≤7℃ and stored in a jacketed tank with ice water.

[0067] 8) Filling and packaging;

[0068] 9) Freezing: Store the packaged milk protein concentrate frozen at ≤-22℃;

[0069] 10) Finished product inspection.

[0070] The test results of the spherical particle products obtained in this embodiment are as follows: lactose content is 1%; protein content is 24%; fat content is 1.8%; calcium content is 565 mg / kg; β-lactoglobulin content is 13.5 mg / mL; lactoferrin content is 598 ug / mL; α-lactoglobulin content is 5.94 mg / mL; and immunoglobulin IgG content is 778 mg / L.

[0071] Example 3

[0072] The specific process for concentrating 2000kg of raw milk is as follows:

[0073] 1) Raw milk is passed through a hydraulic cavitation reactor;

[0074] 2) The parameters for the hydraulic cavitation pretreatment process are: temperature 80℃, flow rate 0.252m³ / h. 3 / h, speed 3800rpm;

[0075] 3) The obtained milk is temporarily stored in a jacketed storage tank; excess milk fat is removed, and the milk is cooled and temporarily stored.

[0076] 4) Ultrafiltration membrane (concentration): The material is concentrated by passing it through an ultrafiltration membrane with a molecular weight of 2000. The outlet pressure of the retentate is controlled at 4.0 bar, and the concentration ratio is 33.5, resulting in lactose-free skim milk with a protein content of 9.5%, a lactose content of 0.3%, and a fat content of 0.16%.

[0077] 5) The lactose-free skim milk is fed into a spray dryer. The lactose-free skim milk is input under high pressure via a diaphragm pump, spraying out as atomized droplets. These droplets then descend in parallel with hot air. Most of the powder particles are collected at the bottom discharge port of the dryer. The waste gas and fine powder are separated by a cyclone separator. The waste gas is discharged by an exhaust fan, and the powder is collected by a powder collection tube located at the lower end of the cyclone separator. After atomization, the surface area of ​​the lactose-free skim milk is greatly increased. In the hot air stream, 98% of the moisture can evaporate within 10-20 seconds, producing uniformly sized, free-flowing spherical particles.

[0078] 6) Cooling and storage: The obtained milk is rapidly cooled to ≤7℃ and stored in a jacketed tank with ice water.

[0079] 8) Filling and packaging;

[0080] 9) Freezing: Store the packaged milk protein concentrate frozen at ≤-22℃;

[0081] 10) Finished product inspection.

[0082] The test results of the spherical particle products obtained in this embodiment are as follows: lactose content is 1%; protein content is 24%; fat content is 1.8%; calcium content is 365 mg / kg; β-lactoglobulin content is 13.5 mg / mL; lactoferrin content is 298 ug / mL; α-lactoglobulin content is 3.94 mg / mL; and immunoglobulin IgG content is 278 mg / L.

[0083] Comparative Example

[0084] The process of concentrating 2000kg of raw milk using traditional methods is as follows:

[0085] 1) Pass raw milk into the pasteurization reactor;

[0086] 2) Heat to 50 to 60°C, pass through a centrifuge at a pressure of 2.0 bar to remove all or part of the fat, standardize, and obtain skim milk with a fat content of 0.06%;

[0087] 3) The obtained skim milk is temporarily stored in a jacketed storage tank; the obtained cream fat is cooled and temporarily stored.

[0088] 4) Washing to reduce sugar content: Mix the obtained milk and purified water at a ratio of 1:11 and test the lactose content to be 0.20%.

[0089] 5) The obtained milk is temporarily stored in a jacketed storage tank; excess milk fat is removed, and the milk is cooled and stored temporarily.

[0090] 6) Ultrafiltration membrane (UF membrane) concentration: The material is concentrated by passing it through an ultrafiltration membrane with a molecular weight of 2000. The outlet pressure of the retentate is controlled at 4.0 bar, the concentration ratio is 33.5%, and lactose-free skim milk with a protein content of 9.5%, lactose content of 0.3%, and fat content of 0.17% is obtained.

[0091] 7) The lactose-free skim milk is fed into a spray dryer. The lactose-free skim milk is input under high pressure via a diaphragm pump, spraying out as atomized droplets. These droplets then descend in parallel with hot air. Most of the powder particles are collected at the bottom discharge port of the dryer. The waste gas and fine powder are separated by a cyclone separator. The waste gas is discharged by an exhaust fan, and the powder is collected by a powder collection tube located at the lower end of the cyclone separator. After atomization, the surface area of ​​the lactose-free skim milk is greatly increased. In the hot air stream, 98% of the moisture can evaporate within 10-20 seconds, producing uniformly sized, free-flowing spherical particles.

[0092] 8) Cooling and storage: The obtained milk is rapidly cooled to ≤7℃ and stored in a jacketed tank with ice water.

[0093] 9) Filling and packaging;

[0094] 10) Freezing: Store the packaged milk protein concentrate frozen at ≤-22℃;

[0095] 11) Finished product inspection.

[0096] The test results of the spherical particles obtained in this comparative example are as follows: lactose content 1.5%; protein content 34%; fat content 0.8%; calcium content 455 mg / kg; β-lactoglobulin content 15.5 mg / mL; lactoferrin content 598 ug / mL; α-lactoglobulin content 5.94 mg / mL; immunoglobulin IgG content 878 mg / L. The viscosity measured at a shear rate of 100 times per second was 230 mPa·s. The average particle size of the concentrated milk protein solution was 36.26 ± 0.76 μm, and the D10, D50, and D90 were 9.08 ± 0.24 μm, 22.92 ± 0.72 μm, and 86.55 ± 3.83 μm, respectively.

[0097] The main difference between Example 1 and Comparative Example 1 is that Example 1 uses hydraulic cavitation technology as a pretreatment step, replacing the pasteurization, water washing for sugar reduction, and defatting steps in the Comparative Example. The experimental data for calcium content and effective protein content are similar, indicating that the hydraulic cavitation pretreatment process for concentrated milk protein achieves similar results to traditional concentrated milk protein treatment methods. Furthermore, hydraulic cavitation treatment can significantly reduce the viscosity of concentrated milk protein and, to some extent, reduce the average particle size and coarse-end particle size, thereby achieving a better distribution effect.

[0098] The main difference between Example 2 and Example 1 lies in the different rotation speeds in the hydraulic cavitation pretreatment. This difference is used to determine the lower limit of the rotor speed in the hydraulic cavitation treatment process. Based on the high lactose and milk fat content in the results, the optimal rotation speed is determined to be >3400 rpm; otherwise, the decomposition of lactose and milk fat cannot be effectively completed.

[0099] The main difference between Example 3 and Experiment 1 lies in the rotation speed during the hydraulic cavitation pretreatment. This is to determine the upper limit of the rotor speed during the hydraulic cavitation process. Based on the low content of active proteins in the results, the optimal rotation speed can be determined to be <3800 rpm. Otherwise, the content of active protein components such as β-lactoglobulin, lactoferrin, α-lactoglobulin, and immunoglobulin IgG will be severely damaged.

[0100] Table 1 shows the inactivation effect of the continuous rotating hydraulic cavitation process of this invention on Escherichia coli, Staphylococcus aureus, and Bacillus cereus (at a temperature of 65°C and a flow rate of 0.252 m³ / h). 3 Table 2 shows the effects of the continuous rotating hydraulic cavitation process of this invention on the mineral, milk protein, milk fat, and vitamin content of raw milk. (At operating conditions of 3600 rpm / h).

[0101] Table 1

[0102]

[0103] Table 2

[0104]

[0105]

[0106] Figure 2 The inactivation effect of the continuous rotating hydrocavitation process of this invention on Escherichia coli, as shown by SEM electron microscopy, is presented. Figure 2 (b) The treated Escherichia coli has a rough surface, more wrinkles, a destroyed cell wall, and intracellular substances that have leaked out; some bacteria are even directly divided in two, and their structure is completely destroyed.

[0107] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dairy processing technology based on continuous hydraulic cavitation, characterized in that, The processing technology is characterized by defatting the dairy product through hydraulic cavitation, and then concentrating the protein in the defatted dairy product through ultrafiltration. The dairy product is milk; The ultrafiltration concentration is achieved through an ultrafiltration membrane; The specific steps of the processing technology are as follows: (1) The dairy products are transported to a hydraulic cavitation reactor for continuous hydraulic cavitation pretreatment; (2) After pretreatment, the dairy product is cooled and the milk fat is removed to obtain defatted emulsion and milk fat; (3) The defatted emulsion is concentrated by passing it through an ultrafiltration membrane to obtain lactose-free defatted milk, wherein the ultrafiltration membrane has a molecular weight of 2000-4000; In step (1), the hydraulic cavitation reactor is a rotor-type hydraulic cavitation reactor with a rotation speed of 3200–3800 rpm; the flow rate of the dairy product entering the hydraulic cavitation reactor is 0.15–0.4 m³ / min. 3 / h; processing temperature reaches 50~75℃; In step (3), the defatted emulsion is concentrated by ultrafiltration membrane, and the molecular weight of ultrafiltration membrane, retentate outlet pressure and concentration ratio are controlled to obtain lactose-free defatted milk. The outlet pressure of the retentate is controlled at 2–4 bar; The concentration ratio is 24 to 33.

5.

2. The dairy processing technology based on continuous hydraulic cavitation as described in claim 1, characterized in that, The rotational speed is 3400–3600 rpm; The flow rate is 0.2–0.3 m³ / s. 3 / h; The processing temperature is 55–70℃.

3. The dairy processing technology based on continuous hydraulic cavitation as described in claim 2, characterized in that, The processing temperature is 60–65°C.

4. The dairy processing technology based on continuous hydraulic cavitation as described in claim 1, characterized in that, In step (3), the molecular weight of the ultrafiltration membrane is 2000-3000.

5. The dairy processing technology based on continuous hydraulic cavitation as described in claim 1, characterized in that, In step (3), the molecular weight of the ultrafiltration membrane is 2000-2500.

6. The dairy processing technology based on continuous hydraulic cavitation as described in claim 5, characterized in that, The outlet pressure of the retentate is controlled at 3-4 bar; The concentration ratio is 30 to 33.

5.

7. The dairy processing technology based on continuous hydraulic cavitation as described in claim 6, characterized in that, The outlet pressure of the retentate is controlled at 3.5–4 bar; The concentration ratio is 33.

5.

8. The dairy processing technology based on continuous hydraulic cavitation as described in claim 1, characterized in that, The processing technology also includes a step of drying the lactose-free skim milk, wherein the drying is spray drying.

9. Dairy products prepared by the dairy processing technology based on continuous hydraulic cavitation as described in any one of claims 1-8.

10. The dairy product prepared by the dairy processing technology based on continuous hydraulic cavitation as described in claim 9, characterized in that, The dairy products mentioned are milk protein and butter.

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