Preparation method of sodium caseinate

Abstract

The invention discloses a preparation method of sodium caseinate. The invention provides a preparation method of sodium caseinate. Raw materials adopted by the method comprise casein. The method comprises the following steps: acid precipitation: adding an acid solution into the raw materials to form a casein micelle dispersion; a capturing step: capturing the casein micelles in the casein micelle dispersion, and the capturing step is carried out for at least three times; and alkali dissolution: adding an alkali solution into the product obtained by the last trapping. According to the preparation method of the sodium caseinate provided by the invention, the production efficiency is greatly improved, the preparation process is milder, the control precision of each process link is high, the protein structure part of the product prepared by the preparation method of the sodium caseinate provided by the invention is low in denaturation degree, and the solubility, the emulsifying efficiency, the foamability and the film-forming property are obviously improved.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to a method for preparing sodium caseinate. Background Art

[0002] Sodium caseinate is a water-soluble protein derivative made from casein through alkaline treatment. Its molecular structure forms a stable complex through the combination of sodium ions and the phosphate groups of casein. As a functional product of natural milk protein, sodium caseinate combines the nutritional properties of casein with excellent processing performance, and is widely used in food, medicine and industrial fields. Its unique physical and chemical properties are manifested in high water solubility, emulsification stability, foaming and film-forming properties, making it irreplaceable in dairy products (such as coffee creamer, ice cream), meat processing (improving texture and water retention), beverages (protein fortification and stabilizer) and nutritional supplements. In addition, sodium caseinate is rich in essential amino acids and has high biological efficacy. It can meet the protein needs of special populations (such as sports nutrition and clinical nutrition), and meets the dual demands of the modern food industry for clean labels and functional ingredients.

[0003] However, the traditional sodium caseinate production process primarily uses qula, a byproduct left behind after herders remove the fat from ghee making. This process results in sodium caseinate products with poor texture, unpleasant flavor, high ash content, low protein content, and significant batch-to-batch fluctuations in product specifications. Furthermore, existing production equipment is relatively crude, generally employing open-type crushing, acid precipitation, water washing, and alkali dissolution equipment. This prevents complete containment and pipeline management of materials throughout the production process, leading to high risks of microbial growth, foreign matter introduction, and chemical contamination. The existing process is relatively inefficient. After acid precipitation, the casein micelles must be repeatedly transferred between tanks, washed and drained using decanter centrifuges and vibrating screens, and then alkali-dissolved. This complex process is difficult to operate and lacks standardized operation. The acid precipitation, water washing, and neutralization steps can lead to partial denaturation of the protein structure, affecting the solubility and emulsification efficiency of the final product. However, current production technology solutions cannot meet the demand of some customers for high-quality sodium caseinate, hindering its innovative application in high-end applications and limiting the development of the industry.

[0004] For example, cited document 1 discloses a preparation process for high-protein sodium caseinate, which comprises the following steps: adding fresh milk or fresh milk-grade casein aqueous solution into a dissolution tank, adding crushed koji, using sodium hydroxide solution as a solubilizing agent, skimming to form a skim milk solution, performing negative pressure vacuum deodorization and ultra-high temperature instantaneous sterilization, then performing acid precipitation by isoelectric precipitation method, dehydrating through a filter press, deblocking and granulating to form granular casein, continuously adding sodium hydroxide solution, repeatedly stirring until the pH value of the solution reaches 6.0, and finally performing coil sterilization and spray drying.

[0005] Reference 2 discloses a production process for sodium caseinate, the main process of which is to mix casein according to 30 mesh size, with protein ≥88% and fat ≤2%, and perform expansion conversion: the prepared materials are fed into an extruder through a feeder, alkali solution is added in proportion for mixing reaction, a certain amount of water is added according to the moisture content of the raw materials, and sodium carbonate is added at 8% by mass of the casein at the same time as the casein. During the expansion conversion reaction, the five temperature sections are: section A temperature is controlled at 50°C, section B temperature is controlled at 70°C, section C temperature is controlled at 100°C, section D temperature is controlled at 125°C, and section E temperature is controlled at 120°C. The conversion time is 20s, and the extruder screw speed is 450r / min. After the reaction, a semi-finished sodium caseinate product is obtained, which is naturally cooled and air-dried by a belt conveyor. The air-dried semi-finished sodium caseinate product is conveyed to a crusher, cut into small cubes, crushed and packaged to obtain the finished sodium caseinate.

[0006] Reference 3 discloses a sodium caseinate production process, which specifically includes screening Qula and crushing it into a powder of 80 to 100 meshes, dissolving the crushed Qula powder into a solution, mixing the solution with raw milk to obtain solution A, separating solution A through a centrifuge to obtain skim milk, sterilizing the skim milk, adding hydrochloric acid to the solution to extract agglomerated protein, filtering the extracted agglomerated protein through a filter press to remove water from the protein, placing the block protein after filtration into a deblocking and granulating machine for deblocking and granulating, sucking the protein particles into a dissolving tank by a suction machine for dissolution and sodiumization, sterilizing the sodiumized material, and placing the sterilized material into a spray drying tower for spray drying.

[0007] Reference 4 discloses a method for converting and producing sodium caseinate, comprising: using casein as a raw material, puffing and converting the casein, uniformly adding the casein to an extruder, adding powdered sodium carbonate with a mass fraction of 8-12% of the casein or introducing a sodium hydroxide solution with a mass fraction of 2-6% simultaneously with the casein, wherein the flow rate of the sodium hydroxide solution is 100-200 L / h, converting the casein and the powdered sodium carbonate or sodium hydroxide solution in an extruder at a temperature of 110-130° C. for a conversion time of 20-25 seconds, and crushing the casein. The puffed and converted sodium caseinate is placed on a conveyor belt, allowed to cool naturally, dried, and then fed into a crusher to obtain a sodium caseinate powder product.

[0008] Therefore, how to improve equipment and / or optimize production processes and expand application scenarios has become an important direction for current industry technology upgrades.

[0009] Citations

[0010] Reference 1: CN114403281A

[0011] Reference 2: CN115777830A

[0012] Reference 3: CN108752450A

[0013] Reference 4: CN104012751A Summary of the Invention

[0014] Problems to be solved by the invention

[0015] In the prior art, there is no industrialized sodium caseinate preparation system and corresponding preparation method. The prior art solutions generally use general equipment and relatively crude processes, which mainly have the following problems:

[0016] 1. The traditional production process of sodium caseinate mainly uses qula, a by-product left after herders remove the oil when making ghee. The raw material quality is poor. The sodium caseinate products produced by this process have poor texture, bad taste, high ash content, low protein content, and large fluctuations in product indicators between batches.

[0017] 2. Existing production equipment is relatively crude, and open crushing, acid precipitation, water washing, and alkali dissolution equipment are generally used. Materials cannot be completely sealed and piped in each link of the production process, and there are high risks of microbial growth, foreign matter introduction, and chemical contamination.

[0018] 3. The production efficiency of the existing process is relatively low. The casein micelles after acid precipitation need to be repeatedly switched between material tanks, washed and drained by means of horizontal screw centrifuges, vibrating screens, etc., and then alkali-dissolved. The process is complicated, the operation is difficult, and standardized operation is impossible.

[0019] 4. The existing production process may cause partial denaturation of the protein structure under extreme pH, high temperature or high ionic strength environment, and its functional properties are easily inhibited, affecting the solubility and emulsification efficiency of the final product.

[0020] In view of this, the present invention provides a method for preparing sodium caseinate, which adopts an industrialized sodium caseinate preparation system to prepare sodium caseinate. The invention uses membrane-separated casein as raw material rather than Qula, and the membrane-separated casein is prepared through the steps of acid precipitation, stirring and capturing, washing and filtration, crushing, alkali dissolution, spray drying and the like. The product indicators of the sodium caseinate prepared by this process are all better than the relevant requirements of GB1886.212-2016; the invention adopts a unique industrial preparation system for sodium caseinate, and the entire production process is completely sealed and pipelined, thereby greatly reducing the risks of microbial breeding, foreign matter introduction, chemical pollution and the like; a unique acid precipitation tank is adopted, and through the original stirring and trapping device design, functions such as material stirring and mixing, casein micelle precipitation and capturing, water replenishment, washing and filtration, and crushing can be achieved in a single acid precipitation tank, thereby avoiding repeated switching of casein micelles between material tanks after acid precipitation, the process is simple, the operation difficulty is low, the standardized operation is easy, and the production efficiency is greatly improved; the preparation process is more gentle, the control precision of each process link is high, the degree of partial denaturation of the protein structure is low, and the solubility, emulsification efficiency, foaming and film-forming properties are significantly improved.

[0021] Solutions for solving problems

[0022] [1]. A method for preparing sodium caseinate, wherein the raw material used in the method includes casein; the method comprises: an acid precipitation step, wherein an acid solution is added to the raw material to form a casein micelle dispersion; a capture step, wherein the casein micelles in the casein micelle dispersion are captured, and the capture step is performed no less than three times; and an alkali dissolution step, wherein an alkali solution is added to the product obtained from the last capture.

[0023] [2] The preparation method according to [1], wherein the casein is obtained by separating from the casein raw material by a membrane separation method.

[0024] [3] The preparation method according to [1] or [2], wherein, in the acid precipitation step, an acid solution is added to the raw material until the pH is 3.5-5.5; and the acid precipitation step is carried out at a temperature not exceeding 60°C.

[0025] [4] The preparation method according to any one of [1] to [3], wherein the time for each capture step does not exceed 10 minutes.

[0026] [5] The preparation method according to any one of [1] to [4], wherein a diafiltration step is further included after each capture step, wherein the diafiltration step comprises diafiltration of the product obtained from each capture in a solvent.

[0027] [6] The preparation method according to any one of [1] to [5], wherein the diafiltration step is carried out at a temperature not exceeding 62°C.

[0028] [7] The preparation method according to any one of [1] to [6], wherein before the alkali dissolution step, it also includes a crushing step, and the crushing step includes crushing the product obtained from the last capture.

[0029] [8] The preparation method according to any one of [1] to [7], wherein the alkaline dissolution step is carried out at a pH of 7-8; and the time for the alkaline dissolution does not exceed 60 minutes.

[0030] [9] The preparation method according to any one of [1] to [8], wherein the method further comprises a post-treatment step, wherein the post-treatment step comprises at least one of sterilization, concentration and drying.

[0031]

[10] The preparation method according to any one of [1] to [9], wherein the preparation method is carried out by using an industrialized sodium caseinate preparation system, wherein the preparation system comprises one or more acid precipitation tanks 40 and one or more alkali dissolution tanks 70,

[0032] The acid precipitation tank 40 is connected to the alkali dissolution tank 70.

[0033] The acid precipitation tank 40 includes a tank body 41, a stirring collector 42, a stirring motor 43 and a stirring main shaft 44. The stirring collector 42 is arranged inside the tank body 41, the stirring collector 42 is connected to the stirring main shaft 44, and the stirring motor 43 is connected to the stirring main shaft 44. The stirring motor 43 can drive the stirring collector 42 and the stirring main shaft 44 to rotate.

[0034] The stirring collector 42 includes a deformable collecting net 421 and a curved collecting net 422. The deformable collecting net 421 extends along the radial direction and the axial direction of the tank body 41, and the curved collecting net 422 extends along the circumferential direction and the axial direction of the tank body 41.

[0035] The deformable capture net 421 includes a plurality of capture net units 4211, a plurality of rotating parts 4212, and a capture unit bracket 4213. The capture net units 4211 are rotatably connected to the capture unit bracket 4213 via the rotating parts 4212. The rotating shaft of the rotating part 4212 extends along the axial direction or a direction parallel to the axial direction of the tank body 41, so that the plurality of capture net units 4211 can change the liquid-facing area of ​​the deformable capture net 421 when rotating around the rotating shaft.

[0036] The plurality of capture net units 4211 are arranged in a matrix on both sides of the stirring main shaft 44;

[0037] Preferably, the acid precipitation step, the capturing step, the filtration step, and the crushing step are all performed in the acid precipitation tank 40 .

[0038]

[11] . Sodium caseinate, wherein the sodium caseinate is prepared by the method described in any one of [1] to

[10] .

[0039]

[12] The sodium caseinate according to

[11] , wherein the protein content of each 100g of sodium caseinate is not less than 89% and the ash content is not more than 5% on a dry basis.

[0040]

[13] The sodium caseinate according to

[11] or

[12] , wherein the moisture content of the sodium caseinate is less than 3% per 100g of sodium caseinate on a dry basis; and the pH of the sodium caseinate is 6-7.5.

[0041]

[14] . A product comprising sodium caseinate prepared according to the preparation method described in any one of [1] to

[10] , or sodium caseinate described in any one of

[11] to

[13] , and any one or more of the following ingredients: plant product ingredients, animal meat product ingredients, animal dairy product ingredients, functional additives, and any acceptable excipients.

[0042]

[15] . The industrial preparation system of sodium caseinate according to

[10] , wherein the stirring collector 42 includes two arc-surface collecting nets 422, the two arc-surface collecting nets 422 are respectively connected to the radial side edges of the deformable collecting net 421, the central angle corresponding to the inner arc surface of the two arc-surface collecting nets 422 is less than 180 degrees, and the circumferential extension direction of the two arc-surface collecting nets 422 relative to the deformable collecting net 421 is counterclockwise; or, the circumferential extension direction of the two arc-surface collecting nets 422 relative to the deformable collecting net 421 is clockwise.

[0043]

[16] . The industrial preparation system of sodium caseinate according to

[15] , wherein the rotation range of the capture net unit 4211 is limited to one side of the main plane of the capture unit bracket 4213, and the side is close to the arc-shaped capture net 422 adjacent to the capture net unit 4211, and the rotation range of the multiple capture net units 4211 on one side of the stirring main shaft 44 and the rotation range of the multiple capture net units 4211 on the other side of the stirring main shaft 44 are respectively limited to two opposite sides of the main plane of the capture unit bracket 4213.

[0044]

[17] . The sodium caseinate industrial preparation system according to

[15] , wherein the stirring collector 42 further includes a collector frame 423, and the collector frame 423 is connected to the stirring main shaft 44 and the two arc-surface collecting nets 422.

[0045]

[18] The sodium caseinate industrial preparation system according to

[10] , wherein the plurality of capture net units 4211 rotate within a range of 0 to 90 degrees from a vertical plane of the capture unit bracket 4213 to a parallel plane of the capture unit bracket 4213.

[0046]

[19] . The industrialized preparation system for sodium caseinate according to

[10] , wherein the mesh of the capture net unit 4211 is a square hole, the side length of the square hole is 4 to 8 mm, 4 to 8 rows of the capture net units 4211 are provided in the deformable capture net 421, and 4 to 6 columns of the capture net units 4211 are provided in the deformable capture net 421.

[0047]

[20] The industrial preparation system of sodium caseinate according to

[10] further comprises a water supply unit 10, a powder bin 20 and a mixer 30, wherein the water supply unit 10 and the powder bin 20 are both connected to the mixer 30 to mix the casein powder with water in the mixer 30.

[0048]

[21] . The industrial preparation system of sodium caseinate according to

[10] further comprises a by-product collection tank 60 and a temporary storage tank 90, wherein the by-product collection tank 60 is connected to the acid precipitation tank 40 and is used to collect the clear liquid formed after the casein is captured in the acid precipitation tank 40, and the temporary storage tank 90 is connected to the alkali dissolution tank 70 and is used to collect the sodium caseinate solution formed in the alkali dissolution tank 70.

[0049]

[22] The industrial preparation system of sodium caseinate according to

[21] further comprises a colloid mill and a sterilizer 80, wherein the colloid mill is arranged between the acid precipitation tank 40 and the alkali dissolution tank 70 for crushing casein micelles, and the sterilizer 80 is arranged between the alkali dissolution tank 70 and the temporary storage tank 90 for sterilizing the sodium caseinate solution.

[0050]

[23] The industrial preparation system of sodium caseinate according to

[21] further comprises an acid tank 51 and an alkali tank 52, wherein the acid tank 51 is connected to the acid precipitation tank 40 for passing acid into the acid precipitation tank 40, and the alkali tank 52 is connected to the alkali dissolving tank 70 for passing alkali into the alkali dissolving tank 70.

[0051] Effects of the Invention

[0052] 1. The present invention uses membrane-separated casein as raw material rather than Qula. The membrane-separated casein is prepared through acid precipitation, stirring and capturing, filtration, crushing, alkali dissolution, and spray drying. The sodium caseinate prepared by this process has a milky white appearance, a slight frankincense aroma, good powder fluidity, ash content ≤5%, protein ≥90%, fat ≤1.8%, moisture ≤4%, no total arsenic detected, no lead detected, total bacterial count ≤3000 (CFU / g), and no coliform bacteria detected. All product indicators exceed the relevant requirements of GB1886.212-2016;

[0053] 2. The present invention adopts a unique industrialized preparation system for sodium caseinate, and the entire production process is completely sealed and pipelined, thereby greatly reducing the risks of microbial growth, foreign matter introduction, and chemical contamination;

[0054] 3. The present invention adopts a unique acid precipitation tank and an original stirring and collecting device design, which can realize the functions of material stirring and mixing, casein micelle precipitation and collection, water replenishment, filtration, and crushing in a single acid precipitation tank, thereby avoiding the casein micelles after acid precipitation from being repeatedly switched between material tanks. The process is simple, the operation difficulty is low, and the standardized operation is easy, the production efficiency is greatly improved, and the yield is higher.

[0055] 4. The preparation process of the present invention is more gentle, the control precision of each process link is high, the degree of denaturation of the protein structure is low, and the solubility, emulsification efficiency, foaming and film-forming properties are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 The figure is a simplified structural diagram of the industrialized preparation system of sodium caseinate of the present invention.

[0057] Figure 2 It is a structural schematic diagram of the acid precipitation tank of the present invention.

[0058] Figure 3 It is a top view of the internal structure of the acid precipitation tank of the present invention.

[0059] Figure 4 It is a structural schematic diagram of the stirring collector of the present invention.

[0060] Figure 5 It is a structural schematic diagram of the deformable capturing net of the present invention.

[0061] Figure 6 It is a schematic diagram of the deformable capturing net of the present invention.

[0062] Figure 7 FIG. 2 is a schematic diagram of another form of the deformable capture net of the present invention.

[0063] Description of Reference Numerals

[0064] 10 Water supply unit

[0065] 11 Hot water tank

[0066] 20 Powder Bin

[0067] 30 Mixer

[0068] 40 Acid sedimentation tank

[0069] 41 tank

[0070] 42 Stirring collector

[0071] 421 Deformable Capture Net

[0072] 4211 Capture Net Unit

[0073] 4212 Rotating part

[0074] 4213 Capture Unit Bracket

[0075] 422 curved surface capture net

[0076] 423 Catcher Frame

[0077] 43 stirring motor

[0078] 44 stirring spindle

[0079] 45 weighing sensor

[0080] 46 Breathing Cap

[0081] 51 Acid Tank

[0082] 52 Lye Tank

[0083] 60 By-product collection tank

[0084] 70 Alkali dissolving tank

[0085] 80 sterilizer

[0086] 90 Temporary Storage Tank DETAILED DESCRIPTION

[0087] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior or preferred over other embodiments.

[0088] In addition, numerous specific details are provided in the following detailed description to better illustrate the present invention. Those skilled in the art will appreciate that the present invention can be practiced without certain specific details. In other instances, methods, means, equipment, and steps well known to those skilled in the art are not described in detail in order to highlight the main points of the present invention.

[0089] Unless otherwise stated, the units used in this specification are international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0090] In this specification, the use of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0091] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "embodiments," etc., mean that the specific elements (e.g., features, structures, properties, and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein and may or may not be present in other embodiments. Furthermore, it should be understood that the elements may be combined in various embodiments in any appropriate manner.

[0092] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0093] <First Aspect>

[0094] A first aspect of the present invention provides a method for preparing sodium caseinate, wherein the raw material used in the method includes casein; the method comprises: an acid precipitation step, in which an acid solution is added to the raw material to form a casein micelle dispersion; a capture step, in which the casein micelles in the casein micelle dispersion are captured, and the capture step is performed no less than three times; and an alkali dissolution step, in which an alkali solution is added to the product obtained by the last capture, thereby obtaining sodium caseinate.

[0095] The sodium caseinate prepared by the industrial preparation method of sodium caseinate provided by the present invention has improved solubility, emulsification efficiency, foaming property and film-forming property, and various indicators of sodium caseinate are better than the relevant requirements of GB1886.212-2016.

[0096] In some embodiments, the preparation method is performed by using an industrialized sodium caseinate preparation system.

[0097] (Sodium Caseinate Industrial Preparation System)

[0098] In some embodiments of the present invention, the sodium caseinate industrial preparation system (hereinafter sometimes referred to as "preparation system") is as follows: Figure 1 As shown, the preparation system may include a water supply unit 10 , a powder silo 20 , a mixer 30 , an acid precipitation tank 40 , an acid solution tank 51 , an alkali solution tank 52 and an alkali solution tank 70 .

[0099] like Figure 1 As shown, the water supply unit 10 and the powder bin 20 can be connected to a mixer 30 for mixing casein powder with water in the mixer 30 to form a casein solution. Preferably, the preparation system can use membrane separation casein powder as the casein raw material, that is, the powder bin 20 can be equipped with a membrane separation casein mixer 30. The mixer 30 can include a mixing paddle for stirring casein powder and water. Preferably, the rotation speed of the mixing paddle can be 2500 to 3500 revolutions per minute, and the mixing stirring time can be 30 to 60 minutes. The mixer 30 (or the pipeline connected thereto) can also be provided with a flow meter to calculate the amount of material added. Figure 1 The connection structure between each powder silo and each mixer is omitted. The powder silo 20 can be located at a higher height than the mixer 30 to allow the casein powder to enter the mixer 30 under the action of gravity. It is understood that in actual production, the preparation system can directly use casein liquid processed by external equipment. In this case, the preparation system does not need to have a powder silo 20 or a mixer 30.

[0100] Further, such as Figure 2 、 Figure 3 and Figure 4 As shown, the acid precipitation tank 40 may include a tank body 41, a stirring collector 42, a stirring motor 43, a stirring spindle 44, a weighing sensor 45 and a breathing cap 46. The stirring collector 42 and the stirring spindle 44 may be arranged inside the tank body 41, and the stirring motor 43 may be arranged outside (upper) of the tank body 41. The stirring collector 42 may be connected to the stirring spindle 44, and the stirring motor 43 may be connected to the stirring spindle 44. When the stirring motor 43 drives the stirring spindle 44 to rotate, the stirring collector 42 may rotate together with the stirring spindle 44. In particular, the direction of rotation of the output shaft of the stirring motor in the present application can be changed at different production stages (the direction of rotation of the stirring spindle 44 connected to the stirring motor 43 will naturally change accordingly), that is, the direction of rotation of the stirring collector 42 can be changed. Exemplarily, in the acid precipitation, capture and crushing steps carried out sequentially in the acid precipitation tank 40, the direction of rotation of the stirring motor 43 may change as the steps are switched. For example (with Figure 3 For example, in the acid precipitation step, the stirring collector 42 can rotate counterclockwise; in the collection step, the stirring collector 42 can rotate clockwise; in the crushing step, the stirring collector 42 can rotate counterclockwise (for a detailed description of each step, please refer to the workflow described later).

[0101] Preferably, the effective volume of the acid precipitation tank 40 may be 3000 to 5000 liters.

[0102] Preferably, the stirring motor 43 may be a variable frequency motor, and its maximum rated power may be 80 to 150 kilowatts.

[0103] like Figure 3 and Figure 4 As shown, the agitation collector 42 may include a deformable collection net 421 and a curved collection net 422. The deformable collection net 421 extends radially and axially along the tank body 41, while the curved collection net 422 extends circumferentially and axially along the tank body 41. It will be understood that the extension direction herein refers to the overall extension direction of the deformable collection net 421 or the curved collection net 422. That is, the deformable collection net 421 may be a rectangular collection net positioned at the centerline of the tank body 41, while the curved collection net 422 may be a cylindrical collection net positioned within the tank body 41.

[0104] Preferably, the diameter of the stirring collector 42 may be 798 to 1072 mm.

[0105] like Figure 5 As shown, the deformable capture net 421 may include a plurality of capture net units 4211, a plurality of rotating parts 4212, and a capture unit bracket 4213. The capture net units 4211 may be rotatably connected to the capture unit bracket 4213 via the rotating parts 4212. The rotating shaft of the rotating part 4212 may extend along the axial direction or parallel to the axial direction of the stirring main shaft 44. In particular, the rotating part 4212 may be disposed on a vertical side of the capture net unit 4211 (with reference to the working posture of the stirring collector), so that the capture net unit 4211 may rotate around a vertical support rod of the capture unit bracket 4213 (i.e., around the axial direction of the tank body 41), thereby changing the liquid-facing area (effective capture area) of the deformable capture net 421.

[0106] Preferably, Figure 5 As shown, a collection net unit 4211 can be rotatably connected to the collection unit bracket 4213 through multiple rotating parts 4212, making the connection of the collection net unit 4211 more reliable. The interval between two adjacent rotating parts 4212 can be 120 to 260 mm.

[0107] like Figure 4 and Figure 5 As shown, multiple capture net units 4211 can be arranged in a matrix on both sides of the stirring main shaft 44. That is, the capture unit bracket 4213 can include multiple parallel vertical support rods, which can be connected by transverse support rods. Each vertical support rod can connect multiple capture net units 4211. Preferably, the spacing between each vertical support rod can be 113 to 248 millimeters (mm), for example 113 mm, 180 mm, 186 mm, or 248 mm.

[0108] Preferably, the mesh of the capture net unit 4211 can be square, and the side length of the square hole can be 4 to 8 mm. The number of rows of the capture net units 4211 in the deformable capture net 421 can be 4 to 8 rows, and the number of columns of the capture net units 4211 in the deformable capture net 421 can be 4 to 6 columns.

[0109] Further, such as Figure 3 and Figure 4 As shown, the stirring collector 42 may include two curved surface collection nets 422, which may be respectively connected to the radially opposite sides of the deformable collection net 421. The central angle corresponding to the inner curved surfaces of the two curved surface collection nets 422 may be less than 180 degrees, that is, the two curved surface collection nets 422 do not overlap in the circumferential direction, so that a space for material to flow through is formed between the two curved surface collection nets 422.

[0110] Furthermore, the two curved capture nets 422 extend counterclockwise relative to the circumferential direction of the deformable capture net 421; alternatively, the two curved capture nets 422 extend clockwise relative to the circumferential direction of the deformable capture net 421. That is, the inner curved surfaces of the two curved capture nets 422 face each other, forming an axisymmetric structure centered on the stirring shaft 44. This structure is beneficial for ensuring the capture effect of casein micelles and improving the rotational stability of the stirring collector 42.

[0111] Further, such as Figure 3 、 Figure 4 and Figure 5 As shown, the rotation range of a capture net unit 4211 can be limited to one side of the main plane of the capture unit bracket 4213 (the main plane is the extension surface of the entire capture unit bracket, for example, the rectangular surface when the capture unit bracket is a rectangular bracket), and this side is close to the curved capture net 422 adjacent to the capture net unit 4211. In other words, the rotation range of the capture net unit 4211 is limited to the inner side of the curved capture net 422 adjacent to the capture net unit 4211.

[0112] Because the two curved capture nets 422 are arranged in an axisymmetric fashion, the rotational ranges of the multiple capture net units 4211 on one side of the agitation shaft 44 and the multiple capture net units 4211 on the other side of the agitation shaft 44 are correspondingly limited to opposite sides of the principal plane of the capture unit bracket 4213. It will be appreciated that this arrangement ensures that the liquid-facing angles of the respective capture net units 4211 and the curved capture net 422 are consistent or similar when the deformable capture net 421 rotates.

[0113] Preferably, the multiple capture net units 4211 rotate within a range of 0 to 90 degrees, from a plane perpendicular to the capture unit support 4213 to a plane parallel to the capture unit support 4213 (herein, the capture net units 4211 can be located to the left or right of the rotating portion 4212 when parallel to the capture unit support 4213), and rotate only on one side of the capture unit support 4213. 0 degrees corresponds to the capture net units 4211 being parallel to the principal plane of the capture unit support 4213, and 90 degrees corresponds to the capture net units 4211 being perpendicular to the principal plane of the capture unit support 4213. For example, the spacing between the vertical struts of the capture unit support 4213 can be appropriately smaller than the horizontal width of the capture net units 4211 (based on the operating posture of the agitator collector) to restrict the rotation of the capture net units 4211, specifically limiting the capture net units to rotation parallel to the principal plane of the capture unit support and preventing them from rotating to the other side of the capture net support. In another possible embodiment, the rotation range of the capturing net unit 4211 may also be limited by the rotating portion 4212 , that is, the maximum rotation angle of the rotating portion 4212 may be 90 degrees.

[0114] Furthermore, the stirring collector 42 may further include a collector frame 423, which can connect the stirring spindle 44 and the two curved collecting nets 422. The collector frame 423 can enhance the structural stability and load capacity of the stirring collector. The angle between the collector frame 423 and the deformable collecting net 421 can be 60 to 90 degrees.

[0115] Based on the structure of the above-mentioned deformable capturing net 421, as Figure 3 As shown, the deformable capture net 421 is Figure 3 In the perspective shown, when the deformable capture net 421 is rotated counterclockwise, the capture net unit 4211 can be rotated to a position perpendicular (or nearly perpendicular) to the main plane of the capture unit bracket 4213 under the action of fluid resistance. Figure 6 As shown, the deformable capturing net 421 has a small liquid-facing area (effective capturing area) and a small capturing ability for casein micelles (almost no capturing function).

[0116] exist Figure 3 In the perspective shown, if the deformable capture net 421 is rotated clockwise, it can be understood that under the fluid resistance and the aforementioned rotation limit conditions of the capture net unit 4211, the capture net unit 4211 can be rotated to a position parallel to the main plane of the capture unit bracket 4213. Figure 7 As shown, the deformable capturing net 421 has a larger liquid-facing area (effective capturing area) and a greater capturing capability for casein micelles.

[0117] For example, in Figure 3From the perspective of , when the deformable capture net 421 is rotated counterclockwise, the stirring collector 42 mainly performs the function of stirring the material. When the deformable capture net 421 is rotated counterclockwise at high speed, the stirring collector 42 can also form a preliminary dispersion and cutting of the casein micelles. When the deformable capture net 421 is rotated clockwise, the stirring collector 42 mainly performs the function of capturing the casein micelles. Moreover, when the deformable capture net 421 is rotated clockwise, the curved capture net 422 can also perform the function of capturing the casein micelles. Furthermore, the acid precipitation tank 40 provided in this embodiment can respectively achieve the functions of stirring the material, capturing the casein micelles and preliminarily dispersing and cutting the casein micelles by adjusting the rotation direction and rotation speed of its stirring collector 42.

[0118] Some preferred examples of specific parameters of the acid precipitation tank are given below:

[0119] Example 1:

[0120] The effective volume of the acid precipitation tank 40 is 3000 liters;

[0121] The diameter of the stirring trap 42 is 798 mm;

[0122] The maximum rated power of the stirring motor 43 is 80 kilowatts;

[0123] The mesh of the arc surface capture net 422 and the deformable capture net 421 is a square hole structure with a side length of 4 mm;

[0124] The deformable capture net 421 is arranged in four groups in the longitudinal direction, and a rotating part 4212 is installed at every 260 mm interval on the longitudinal side frame;

[0125] The deformable capturing nets 421 are arranged in six groups in a horizontal direction; the rotation angle range of the rotating portion 4212 is 0-90 degrees.

[0126] The angle between the trap frame 423 and the deformable trapping net 421 is 60 degrees;

[0127] The spacing between the vertical struts of the capture unit bracket 4213 is 113 mm.

[0128] Example 2:

[0129] The effective volume of the acid precipitation tank 40 is 5000 liters;

[0130] The diameter of the stirring trap 42 is 1072 mm;

[0131] The maximum rated power of the stirring motor 43 is 150 kilowatts;

[0132] The mesh of the arc surface capture net 422 and the deformable capture net 421 is a square hole structure with a side length of 8 mm;

[0133] The deformable capture net 421 is arranged in 8 groups in the longitudinal direction, and a rotating part 4212 is installed at every 120 mm interval on the longitudinal side frame;

[0134] The deformable capture net 421 is arranged in four groups in a horizontal direction; the rotation angle range of the rotating part 4212 is 0-90 degrees;

[0135] The angle between the trap frame 423 and the deformable trapping net 421 is 90 degrees;

[0136] The spacing between the vertical supports of the capture unit bracket 4213 is 248 mm.

[0137] Example 3:

[0138] The effective volume of the acid precipitation tank 40 is 4000 liters;

[0139] The diameter of the stirring trap 42 is 824 mm;

[0140] The maximum rated power of the stirring motor 43 is 120 kilowatts;

[0141] The mesh of the arc surface capture net 422 and the deformable capture net 421 is a square hole structure with a side length of 6 mm;

[0142] The deformable capture net 421 is arranged in 6 groups in the longitudinal direction, and a rotating part 4212 is installed at every 190 mm interval on the longitudinal side frame;

[0143] The deformable capture net 421 is arranged in four groups in a horizontal direction; the rotation angle range of the rotating part 4212 is 0-90 degrees;

[0144] The angle between the trap frame 423 and the deformable trapping net 421 is 75 degrees;

[0145] The spacing between the vertical supports of the capture unit bracket 4213 is 186 mm.

[0146] Preferably, the preparation system can be provided with multiple acid precipitation tanks to improve the efficiency of the acid precipitation operation.

[0147] It is understood that the acid precipitation tank 40 may also be provided with a temperature maintenance system to maintain the temperature in the acid precipitation tank 40 within a certain range.

[0148] The weighing sensor 45 of the acid precipitation tank 40 can be set outside the tank body 41 to weigh the total weight of the acid precipitation tank 41 and the materials therein. Combined with the weight of the acid precipitation tank 41 itself, the weight of the materials in the acid precipitation tank 41 and the amount of materials added each time can be calculated.

[0149] The breathing cap 46 (breathing valve) of the acid precipitation tank 40 can be arranged on the upper part of the tank body 41, which can have the functions of balancing the internal and external pressures of the tank body, preventing pollution and dust, etc.

[0150] After the casein micelles are initially fragmented in the acid precipitation tank 40, they can enter the colloid mill for sufficient crushing. The fully crushed casein material can then be pumped into the alkaline dissolution tank 70 by a pump (particularly a screw pump). Preferably, the preparation system in this embodiment can also include a sterilizer 80 and a temporary storage tank 90. ​​The sodium caseinate solution formed in the alkaline dissolution tank 70 can be further pumped into the sterilizer 80 by a pump (particularly a screw pump) for sterilization, and then passed into the temporary storage tank 90 for thermal insulation storage.

[0151] The sodium caseinate solution produced by the above preparation system can be further subjected to steps such as evaporation concentration and spray drying to form the final sodium caseinate product.

[0152] (raw material)

[0153] In the method for preparing sodium caseinate provided by the present invention, the raw material includes casein. In some embodiments, the method uses casein as the raw material. In some embodiments, the raw material does not include quercetin. In this specification, casein is a phosphate-calcium binding protein that is acid-sensitive and precipitates at low pH. Casein is the main protein in the milk of mammals, including cows, sheep, and humans, and is also known as casein, casein, and lactocasein.

[0154] In principle, the source of casein in the present invention is not particularly limited. For example, the casein may be derived from various animal milks, such as cow's milk, goat's milk, horse's milk, camel's milk, and the like.

[0155] In some embodiments, the raw casein used to prepare sodium caseinate can be separated from a casein raw material (e.g., milk) by a membrane separation method. Separating casein from a casein raw material (e.g., milk) by a membrane separation method can improve the quality of the raw material, and the resulting sodium caseinate product has a better texture, a better flavor, a lower ash content, and a higher protein content.

[0156] In the present invention, the membrane separation method refers to the use of a filter membrane with an appropriate pore size to intercept and separate protein components of different molecular weights, thereby obtaining the casein solution of the present invention. In some specific embodiments, the membrane separation method uses a ceramic membrane or a spiral membrane for membrane separation, that is, the casein solution of the present invention can be a casein solution prepared by a membrane separation method using a ceramic membrane or a spiral membrane.

[0157] In some embodiments, the source of the raw material casein for preparing sodium caseinate of the present invention can be milk, dairy products or any other raw material (sample) containing casein, such as a food sample.

[0158] In some embodiments, the raw casein of the present invention may be membrane-separated casein powder or membrane-separated casein liquid. Preferably, the raw casein is casein liquid.

[0159] Direct production using membrane-separated casein solution as raw material can omit the process of raw material dissolution, improve production efficiency and increase product yield.

[0160] In some exemplary embodiments, when the raw casein of the present invention is membrane-separated casein powder, the raw material can be dissolved to obtain a raw casein solution. Preferably, the solvent for dissolving the raw material is water, more preferably RO water.

[0161] The RO water described in the present invention is obtained by filtering through reverse osmosis membrane technology.

[0162] In some preferred embodiments, when the raw materials are subjected to dissolution treatment, the dissolution temperature is not higher than 58°C, preferably 50-55°C.

[0163] In some embodiments, the raw materials are dissolved in a mixer. In some embodiments, the stirring blade of the mixer rotates at a speed of 2500-3500 r / min, and the mixing time is 30-60 min.

[0164] In some preferred embodiments, the dissolution treatment of the raw materials includes: the membrane separated casein powder is pumped into the mixer 30 to start mixing, the stirring blade of the mixer 30 rotates at a speed of 2500-3500 r / min, and the mixing time is 30-60 min.

[0165] In some more preferred embodiments, when the stirring blade speed of the mixer 30 is 2500 r / min, the mixing time is 60 min; when the stirring blade speed of the mixer 30 is 3500 r / min, the mixing time is 30 min; when the stirring blade speed of the mixer 30 is 3000 r / min, the mixing time is 45 min.

[0166] In some embodiments, the casein solution has a dry matter content of ≥10g / 100g, protein (on a dry basis) ≥84g / 100g, casein (as a percentage of protein) ≥82g / 100g, and fat (on a dry basis) ≤5g / 100g.

[0167] In some optional embodiments, the raw casein liquid of the present invention has a dry matter content of 10-15 g / 100 g, a protein (on a dry basis) content of 84-90 g / 100 g, a casein (as a percentage of protein) content of 82-88 g / 100 g, and a fat (on a dry basis) content of 0-5 g / 100 g. For example, the casein liquid has a dry matter content of 12.1 (g / 100 g), a protein (on a dry basis) content of 86.4 (g / 100 g), a casein (as a percentage of protein) content of 85.6 (g / 100 g), and a fat (on a dry basis) content of 0.74 (g / 100 g); the casein liquid has a dry matter content of 12.5 (g / 100 g), a protein (on a dry basis) content of 8 6.2 (g / 100g), casein (accounting for protein) 85.4 (g / 100g), fat (on dry basis) 0.89 (g / 100g); casein liquid dry matter content 12.3 (g / 100g), protein (on dry basis) 86.7 (g / 100g), casein (accounting for protein) 85.9 (g / 100g), fat (on dry basis) 0.66 (g / 100g); casein liquid dry matter content 12.2 (g / 100g), protein (on dry basis) 86.6 (g / 100g), casein (accounting for protein) 85.2 (g / 100g), fat (on dry basis) 0.74 (g / 100g).

[0168] Raw casein liquid that meets the above indicators is beneficial to the preparation of sodium caseinate, achieving product effects with better solubility, emulsification efficiency, foaming and film-forming properties.

[0169] (Acid precipitation)

[0170] In some embodiments, the acid precipitation step of the present invention includes adding an acid solution to the raw material (e.g., casein solution or casein solution obtained by dissolving casein powder). After adding the acid solution, the casein solution can form casein precipitated particles, which then aggregate to form a casein micelle dispersion.

[0171] In some embodiments, the acid solution used in the acid precipitation step may be an acid solution commonly used by those skilled in the art.

[0172] In some preferred embodiments, the acid solution used in the acid precipitation step is a food-grade dilute hydrochloric acid solution. More preferably, the mass fraction of the food-grade dilute hydrochloric acid solution is 10-15%, for example, 11.5%, 12%, 12.5%, 13%, 13.5%, etc.

[0173] In some embodiments, in the acid precipitation step, an acid solution is added to the raw material to a pH of 3.5-5.5 (for example, when an acid precipitation tank is used for acid precipitation, the pH of the material in the acid precipitation tank is), preferably, the pH is 4-5, more preferably, the pH is 4.1-4.6, for example, the pH is 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, etc.

[0174] In some embodiments, the acid precipitation step is carried out at a temperature not exceeding 60°C. Preferably, the acid precipitation step is carried out at a temperature between 40-55°C, for example, 40°C, 42°C, 45°C, 48°C, 50°C, 52°C, 55°C, etc.

[0175] At the above pH and temperature, casein can be promoted to further form casein micelles.

[0176] In some specific embodiments, the acid precipitation step ends when the casein micelles are fully formed.

[0177] In some embodiments, the acid precipitation step is performed in an acid precipitation tank 40 equipped with a stirring collector 42 and other components as described above.

[0178] In some specific embodiments, during the addition of the acid solution, the stirring collector 42 continues to rotate at 30-60 r / min. When the precipitated casein particles gradually aggregate and grow to form casein micelles, the stirrer is adjusted to rotate at 10-20 r / min until the casein micelles are completely formed, and the acid precipitation step is completed.

[0179] by Figure 3 As an example, the acid precipitation step is as follows: Figure 1 As shown, the mixer 30 can be connected to the acid precipitation tank 40, and the casein solution formed by the mixing of the mixer 30 can enter the acid precipitation tank 40. The acid solution tank 51 can be connected to the acid precipitation tank 40 to add dilute hydrochloric acid solution (food grade) to the casein solution. Preferably, after the casein solution enters the acid precipitation tank 40, the temperature can be maintained at 40 to 55 degrees Celsius, and food grade dilute hydrochloric acid can be slowly added until the pH value of the casein solution stabilizes to 4.1 to 4.6.

[0180] During the above process, the stirring collector 42 can continue to rotate counterclockwise at a medium speed. When the precipitated casein particles gradually aggregate and grow to form casein micelles, the stirring collector 42 can be adjusted to rotate counterclockwise at a low speed until the casein micelles are completely formed and the acid precipitation step is completed.

[0181] In some preferred embodiments, in the acid precipitation step, during the addition of the acid solution, the stirring collector 42 is continuously rotated counterclockwise at 30-60 r / min. Figure 3From a perspective, when deformable collection net 421 rotates counterclockwise, stirring collector 42 primarily stirs the material. As the precipitated casein particles gradually aggregate and grow to form casein micelles, stirring collector 42 rotates counterclockwise at a rate of 10-20 rpm until the casein micelles are fully formed, completing the acid precipitation step.

[0182] In some more preferred embodiments, during the addition of the acid solution, the stirring collector 42 is first rotated counterclockwise at speeds of 30 r / min, 50 r / min, and 60 r / min. When the precipitated casein particles gradually aggregate and grow to form casein micelles, the stirring collector 42 is then rotated counterclockwise at speeds of 10 r / min, 15 r / min, and 20 r / min until the casein micelles are completely formed.

[0183] After the acid precipitation step, as will be described in detail below, the capture step can be performed multiple times (particularly, three capture steps can be performed), and the acid precipitation tank can be filtered (i.e., the clear liquid in the acid precipitation tank is discharged and then replenished with deionized water) between each capture step.

[0184] (Capture)

[0185] In some embodiments, the capturing step of the present invention comprises capturing the casein micelles in the casein micelle dispersion.

[0186] In some embodiments, the capturing step is performed no less than three times. Preferably, the capturing step is performed three times.

[0187] In some embodiments, in each capture step, the capture time does not exceed 10 minutes. Preferably, the capture time is 2.5-5 minutes, for example, 2.5 minutes, 3 minutes, 3.5 minutes, 4.5 minutes, 5 minutes, etc.

[0188] In some embodiments, the capturing step is performed in an acid precipitation tank.

[0189] In some exemplary embodiments, in the capturing step, the casein micelle precipitate is captured by a capturing system in an acid precipitation tank.

[0190] In some preferred embodiments, Figure 3For example, after the acid precipitation is complete, the stirring collector 42 can be adjusted to rotate clockwise at high speed. Each capture net unit 4211 in the deformable capture net 421 can be rotated 90 degrees counterclockwise by the rotating portion 4212 under the action of resistance until it is aligned with or parallel to the capture unit bracket 4213. The curved capture net 422 and the deformable capture net 421 form a complete casein micelle precipitation and capture system. The casein micelle precipitate is intercepted by the stirring collector 42 under the action of centrifugal force, gradually forming a filter layer. The capture process continues for a certain period of time and ends, completing the capture of the casein micelle precipitate.

[0191] In some preferred embodiments, the stirring collector 42 is adjusted to rotate clockwise at 80-120 rpm. Each capture net unit 4211 in the deformable capture net 421 can be rotated counterclockwise 90 degrees by the rotating portion 4212 under the action of resistance until it overlaps or becomes parallel with the capture unit bracket 4213. Under the action of centrifugal force, the casein micelle precipitate is intercepted by the stirring collector 42, gradually forming a filter layer. The casein micelles are then captured by the casein micelle precipitation and capture system composed of the curved capture net 422 and the deformable capture net 421. The capture process lasts for 2.5-5 minutes, completing the first capture of the casein micelle precipitate.

[0192] In some specific embodiments, the second capture step includes: immediately adjusting the stirring collector 42 to rotate clockwise at 80-120 r / min, and the capture process lasts for 2.5-5 minutes before it ends, thereby completing the secondary capture of casein micelle precipitation.

[0193] In some specific embodiments, the third capture step includes: the stirring collector 42 is immediately adjusted to rotate clockwise at 80-120 r / min, and the three capture processes are completed after 2.5-5 minutes, thereby completing the three captures of casein micelle precipitation.

[0194] In some more preferred embodiments, the stirring collector 42 is adjusted to rotate clockwise at speeds of 80 r / min, 100 r / min, and 120 r / min, and the speed and capture time of the stirring collector 42 are the same during each capture process.

[0195] (Diafiltration)

[0196] In some specific embodiments, the present invention further comprises a diafiltration step after each capture step, wherein the diafiltration step comprises diafiltration of the product obtained from each capture in a solvent. In some embodiments, the solvent used in the diafiltration is water, preferably RO water.

[0197] In some embodiments, the number of diafiltrations depends on the number of captures. Generally, after all captures except the last one are completed, a washing step is performed. For example, when three captures are performed, diafiltration is performed after the first and second captures.

[0198] In some embodiments, the diafiltration step is performed at a temperature not exceeding 62°C. Preferably, the diafiltration step is performed at a temperature of 40-55°C, for example, 40°C, 42°C, 45°C, 48°C, 50°C, 52°C, 55°C, etc.

[0199] In some embodiments, in the diafiltration step, the diafiltration time does not exceed 5 minutes. Preferably, the washing time is 1.5-3 minutes, for example, 1.5 minutes, 2 minutes, 2.2 minutes, 2.5 minutes, 3 minutes, etc.

[0200] In some embodiments, the diafiltration step is performed in an acid precipitation tank. In some preferred embodiments, a second diafiltration step is performed after the first capture, the first diafiltration step comprising: after the casein micelle precipitation and capture are completed, the rotation speed of the stirring trap 42 is maintained unchanged, while the clear liquid in the acid precipitation tank 40 is discharged into the by-product collection tank 60; after the clear liquid is emptied, 40-55°C RO water is added to the acid precipitation tank 40 to a set liquid level, and the stirring trap 42 is immediately adjusted to rotate counterclockwise at 10-20 rpm. The diafiltration process is continued for 1.5-3 minutes before it ends.

[0201] In some preferred embodiments, a secondary diafiltration is performed after the second capture, and the secondary diafiltration step includes: after the secondary capture of the casein micelle precipitation is completed, the rotation speed of the stirring collector 42 is continued to remain unchanged, and the clear liquid in the acid precipitation tank 40 is drained to the ground. After the clear liquid is emptied, 40-55°C RO water is added to the acid precipitation tank 40 to the set liquid level, and the stirring collector 42 is immediately adjusted to 10-20 r / min counterclockwise rotation. The diafiltration process lasts for 1.5-3 minutes and then ends.

[0202] In some more preferred embodiments, the rotational speed of the stirring collector 42 can be 10 r / min, 15 r / min, or 20 r / min in counterclockwise rotation, and the rotational speed of the stirring collector 42 is the same during each diafiltration process.

[0203] (broken)

[0204] In some embodiments, a step of crushing the product obtained by the last capture is required.

[0205] The present invention has no particular limitation on the crushing method, which may be a common method used by those skilled in the art. In some preferred embodiments, the crushing method is dispersion or cutting.

[0206] In some embodiments, the crushing step is performed in an acid settling tank.

[0207] In some preferred embodiments, the crushing step includes: after the casein micelle precipitate is captured three times, the speed of the stirring collector 42 is maintained unchanged, and the clear liquid in the acid precipitation tank 40 is drained to the ground. After the clear liquid is drained, 40-55°C RO water is added to the acid precipitation tank 40 to the set liquid level, and the stirring collector 42 is immediately adjusted to 90-140r / min counterclockwise rotation. The casein micelle precipitate is dispersed and cut by the stirring collector 42 (especially the capture unit bracket 4213), as shown in FIG. Figure 3 As shown, when the deformable collecting net 421 rotates counterclockwise at high speed, the stirring collector 42 preliminarily disperses and cuts the casein micelles and evenly disperses them in the material system. The speed of the stirring collector 42 is kept constant, and the material is continuously discharged into the colloid mill for sufficient crushing, and then pumped into the alkali dissolution tank 70 by the screw pump.

[0208] In some more preferred embodiments, the stirring collector 42 may rotate counterclockwise at a speed of 90 r / min, 115 r / min, or 140 r / min.

[0209] (Alkali soluble)

[0210] In some embodiments, the alkaline dissolution step of the present invention comprises adding an alkaline solution to the product obtained by the last capture.

[0211] In some preferred embodiments, the alkali dissolution step of the present invention comprises adding an alkali solution to the product obtained by the above-mentioned crushing.

[0212] In some embodiments, the alkali dissolution step is performed in an alkali dissolution tank.

[0213] In some exemplary embodiments, after being preliminarily segmented in the acid precipitation tank 40 , the casein micelles may enter the colloid mill for sufficient crushing, and the sufficiently crushed casein material may then be pumped into the alkaline dissolution tank 70 by a pump (particularly a screw pump).

[0214] In some embodiments, the alkaline solution used in the alkaline dissolution step may be an alkaline solution commonly used by those skilled in the art.

[0215] In some preferred embodiments, the alkaline solution is a food-grade sodium hydroxide solution. More preferably, the mass fraction of the food-grade sodium hydroxide solution is 10-15%, such as 11.5%, 12%, 12.5%, 13%, 13.5%, etc.

[0216] In some embodiments, in the alkali dissolution step, the pH of the alkali dissolution step is carried out at a condition of 7-8. Preferably, the pH of the alkali dissolution step is carried out at a condition of 7-7.5, for example, the pH is 7, 7.1, 7.2, 7.3, 7.4, 7.5, etc.

[0217] In some embodiments, in the alkali dissolution step, the temperature of the alkali dissolution does not exceed 60°C. Preferably, the alkali dissolution temperature is 40-55°C, for example, 40°C, 42°C, 45°C, 48°C, 50°C, 52°C, 55°C, etc.

[0218] In some embodiments, in the alkali dissolution step, the alkali dissolution time is no more than 60 min. Preferably, the alkali dissolution time is 20-50 min, for example, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, etc.

[0219] In some preferred embodiments, during the alkali dissolution step, the crushed product is continuously kept warm at 40-55° C., and a food-grade sodium hydroxide solution is slowly added until the pH stabilizes at 7.0-7.5. The addition of alkali is completed, and the stirring collector 42 rotates at a speed of 2000-3000 r / min, and the alkali dissolution time is 20-50 min.

[0220] In some preferred embodiments, the mass fraction of the sodium hydroxide solution is 12-13%, and is prepared in advance in the alkali solution tank 52 for use.

[0221] In some more preferred embodiments, the rotation speed of the stirring collector 42 may be 2000 r / min, 2500 r / min, or 3000 r / min.

[0222] (Post-processing)

[0223] In some embodiments, the preparation method of the present invention further comprises a post-processing step, wherein the post-processing step comprises at least one of sterilization, concentration and drying.

[0224] Sterilization

[0225] After obtaining the alkali-dissolved product, it can be optionally treated using conventional sterilization / sterilization methods in the art.

[0226] In principle, there is no particular limitation on the above-mentioned treatment method. For example, it can be carried out by heat treatment, high-temperature sterilization, ultraviolet sterilization, pasteurization or ultra-high temperature instantaneous sterilization.

[0227] In some preferred embodiments, the sterilization method is to place the product in a scraper sterilizer for sterilization.

[0228] Preferably, the preparation system includes a sterilizer 80 and a temporary storage tank 90. ​​The sodium caseinate solution formed in the alkali dissolution tank 70 can be further pumped into the sterilizer 80 via a pump (particularly a screw pump) for sterilization, and then passed into the temporary storage tank 90 for heat preservation and storage.

[0229] Preferably, the sterilizer 80 can be a scraper sterilizer.

[0230] In some more preferred embodiments, the temperature during sterilization is not lower than 72°C, and more preferably, the temperature is not higher than 80°C, for example, 72°C, 73°C, 74°C, 75°C, or 76°C.

[0231] concentrate

[0232] After obtaining the sterilized product, it can be optionally treated by conventional concentration methods in the art. In principle, there is no particular limitation on the above treatment method, and for example, vacuum concentration, heating evaporation, ultrafiltration, or reverse osmosis can be used.

[0233] In some preferred embodiments, the sterilized product is placed in an evaporator for concentration.

[0234] dry

[0235] After obtaining the concentrated product, it can be optionally processed using a conventional concentration method in the art. There is no particular limitation on the drying method of the present invention, and vacuum drying, freeze drying, air flow drying, microwave drying, spray drying, etc. can be used. In some preferred embodiments, spray drying can be used.

[0236] In some preferred embodiments, the sterilized sodium caseinate solution is pumped into an evaporator for concentration and then spray-dried to obtain a finished sodium caseinate product.

[0237] The sodium caseinate prepared according to the method of the present invention can improve the yield of the product and shorten the production time.

[0238] In some specific embodiments, the preparation method of sodium caseinate provided by the present invention reduces single-batch production time and improves product yield compared with existing preparation methods.

[0239] In some preferred embodiments, the method for preparing sodium caseinate provided by the present invention has a product yield of not less than 93%.

[0240] <Second Aspect>

[0241] The second aspect of the present invention provides sodium caseinate, which is obtained according to the industrial preparation method of sodium caseinate described in the first aspect.

[0242] In some embodiments, the sodium caseinate has a protein content of not less than 89% per 100 g of sodium caseinate on a dry basis.

[0243] In some preferred embodiments, the sodium caseinate has a protein content of not less than 89% and a fat content of not more than 1.8% per 100 g of sodium caseinate on a dry basis.

[0244] In some preferred embodiments, the sodium caseinate has an ash content of no more than 5% per 100 g of sodium caseinate on a dry basis.

[0245] In some embodiments, the sodium caseinate has a moisture content of no more than 6% per 100 g of sodium caseinate on a dry basis.

[0246] In some preferred embodiments, the sodium caseinate has a moisture content of no more than 4% per 100 g of sodium caseinate on a dry basis. More preferably, the sodium caseinate has a moisture content of no more than 3% per 100 g of sodium caseinate on a dry basis. Further preferably, the sodium caseinate has a moisture content of no more than 2.5% per 100 g of sodium caseinate on a dry basis.

[0247] In some embodiments, the pH value of the sodium caseinate is between 6.0 and 7.5. Preferably, the pH value of the sodium caseinate is between 7.0 and 7.5.

[0248] The sodium caseinate prepared by the present invention has a milky white appearance, a slight frankincense aroma, good powder fluidity, and product indicators that are superior to the relevant requirements of GB1886.212-2016.

[0249] In some embodiments, the total colony count of the sodium caseinate is less than 8000 (CFU / g), preferably, the total colony count of the sodium caseinate is less than 5000 (CFU / g), and more preferably, the total colony count of the sodium caseinate is less than 2500 (CFU / g).

[0250] In the present invention, the measurement of the total colony count is performed with reference to the GB4789.2 method.

[0251] In some embodiments, the wettability time of the sodium caseinate is less than 300 s, preferably, the wettability time of the sodium caseinate is less than 280 s, and more preferably, the wettability time of the sodium caseinate is less than 260 s.

[0252] In the present invention, the wettability time refers to the time it takes for a sample in powder form to be completely immersed in distilled water at 50° C., wherein the mass ratio of sodium caseinate to distilled water is 3:20.

[0253] In some embodiments, the volume ratio of the emulsified serum of the sodium caseinate to the precipitate is lower than 1.5. Preferably, the volume ratio of the emulsified serum of the sodium caseinate to the precipitate is lower than 1.3.

[0254] In the present invention, the ratio of the emulsified serum volume to the sediment volume refers to the volume of the product divided into the serum volume and the sediment volume after the product becomes an emulsion and is subjected to stratification treatment. The emulsified serum volume and the sediment volume can reflect the emulsification performance of the product.

[0255] In the present invention, the emulsion is prepared by adding sodium caseinate to distilled water at 50°C, wherein the mass ratio of sodium caseinate to distilled water is 3:20, taking 10 mL of the liquid into a centrifuge tube, centrifuging at 3000 rpm for 5 minutes to accelerate stratification, and observing the stratification.

[0256] In the present invention, the emulsion is a sodium caseinate emulsion, which is a colloidal dispersion system with a stable dispersed phase in the form of oil-in-water or water-in-oil.

[0257] In some embodiments, the foam volume half-life time of the sodium caseinate is not less than 86 min, preferably, the foam volume half-life time of the sodium caseinate is not less than 95 min, and more preferably, the foam volume half-life time of the sodium caseinate is not less than 100 min.

[0258] In the present invention, the foam volume half-life time of sodium caseinate refers to the time required for the foam volume to decay to 50% of the initial volume. The foam is prepared by mixing sodium caseinate and distilled water and beating at 1000 rpm for 2 minutes, wherein the mass ratio of sodium caseinate to distilled water is 3:20.

[0259] In some embodiments, the tensile breaking stress of the sodium caseinate is not less than 4.9 MPa, preferably, the tensile breaking stress of the sodium caseinate is not less than 5.5 MPa, and more preferably, the tensile breaking stress of the sodium caseinate is not less than 5.9 MPa.

[0260] In the present invention, the measurement of tensile breaking stress is performed with reference to the GB / T 1040 method.

[0261] The sodium caseinate described in the second aspect of the present invention, prepared by the preparation method of sodium caseinate provided by the first aspect of the present invention, is superior to the relevant requirements of GB1886.212-2016, and significantly reduces the risks of microbial growth, foreign matter, chemical contamination, etc. in the product, further reduces the degree of denaturation of the protein structure of the product, and significantly improves the solubility, emulsification efficiency, foaming and film-forming properties.

[0262] <Third Aspect>

[0263] The present invention provides a product, which comprises sodium caseinate prepared by the preparation method of the first aspect of the present invention or the sodium caseinate described in the second aspect of the present invention.

[0264] In addition to the above-mentioned essential components, the product of the present invention may also include other ingredients according to the needs of the final product, and examples thereof include:

[0265] Plant product ingredients, including fruits or their extracts such as figs, pomegranates, kiwis, tangerines, oranges, pineapples, strawberries, apples, rubber, grapes, pears, cherries, blueberries, blackberries, blackcurrants, cranberries, raspberries, melons, emblica chinensis and bilberries; fruits and vegetables such as onions, cucumbers, tomatoes, cauliflower, carrots, spinach, kale, Brussels sprouts, garlic, basil, oregano, or their extracts; grains such as rice (indica rice, japonica rice, glutinous rice), wheat (wheat, barley, oats, rye), corn, sorghum, millet, sorghum, millet, buckwheat, soybeans, broad beans, peas, mung beans, red beans, kidney beans, or their extracts; nuts such as walnuts, pistachios, cashews, hazelnuts, almonds, apricots, pine nuts, peanuts, melon seeds, chestnuts, macadamia nuts, ginkgo nuts, or their extracts; coffee or its extracts; and some botanical Chinese medicinal materials or their extracts that are both medicinal and edible.

[0266] Animal meat product ingredients, including meat product ingredients from pigs, cattle, sheep, aquatic products or poultry.

[0267] Animal dairy ingredients include fresh milk from cows, sheep, etc., as well as processed dairy products such as milk powder, whey protein or cheese.

[0268] Functional added ingredients, including vitamins (one or more of vitamin A, β-carotene, vitamin D3, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, pantothenic acid, folic acid, niacin, choline, inositol, biotin, L-carnitine, lutein); starch; modified starch; amino acids (L-lysine-L-glutamic acid, L-glutamic acid, L-arginine, L-tryptophan, L-glutamine, taurine, L-valine, L-isoleucine, L-leucine, casein phosphopeptide, etc.); dietary fiber (inulin, konjac flour, galacto-oligosaccharides, fructo-oligosaccharides, raffinose, polydextrose, isomaltooligosaccharides, soybean polysaccharides, cyclodextrin, resistant dextrin or dextrin). soy fiber, etc.); trace element supplements (which may include metal ion salts of organic acids, such as calcium citrate, calcium L-lactate, calcium hydrogen phosphate, potassium gluconate, sodium citrate, ferrous gluconate, potassium iodide, zinc gluconate, sodium selenite, copper gluconate, chromium sulfate, manganese gluconate and magnesium gluconate, etc.), fat supplements (such as saturated fatty acids, polyunsaturated fatty acids, monounsaturated fatty acids, OPO structural lipids, OPL structural lipids, LPL structural lipids, DHA, EPA, ARA, phospholipids, etc.); nucleotide supplements; human milk oligosaccharides (such as 2'-FL, 3-FL, DFL, LNFPI, LNFPII, LNT, LNnT, 3'-SL, 6'-SL, DSLNT, etc.), etc.

[0269] Any acceptable excipients include, but are not limited to, solvents, antioxidants, antibacterial agents, thickeners, diluents, solubilizers, stabilizers, fillers, disintegrants, lubricants, anti-caking agents, flavoring agents, sweeteners, edible flavors, edible colorings, etc.

[0270] The present invention does not specifically limit the specific types of the above products.

[0271] In some embodiments, the product is a food, a food additive and / or a health food.

[0272] For different product categories, the present invention does not specifically limit the specific form of the product. For example, it can be in the form of solid, liquid or semi-solid.

[0273] The present invention does not specifically limit the target population of the product. For example, the product can be used for infants, children, teenagers or adults.

[0274] In some embodiments, the product of the present invention can be infant formula, baby food, children's formula, children's snacks, milk powder for pregnant women, milk powder for the middle-aged and elderly, or nutritional or dietary supplements.

[0275] In other embodiments, the products described in the present invention can be beverages (carbonated beverages, fruit and vegetable juice beverages, functional beverages, tea beverages, milk beverages, alcoholic beverages, instant coffee, cereal powder, nut powder or lotus root powder, etc.), candies (jelly candies, hard candies, compressed candies, etc.), milk and dairy products (fresh milk from fresh cow (sheep) milk, milk powder, whey powder, fermented milk, cheese or condensed milk, etc.), pasta products (noodles, instant noodles, steamed buns, dumplings or wontons, as well as baked goods such as bread, cakes or biscuits), etc.

[0276] Example

[0277] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be obtained commercially.

[0278] Example 1:

[0279] 1. Raw material dissolution: First, put the membrane separated casein powder into the powder bin 20. The RO water is heated to 50°C by the water supply unit 10 and enters the hot water tank 11 for temporary insulation. The hot water enters the mixer 30 from the hot water tank 11. When the hot water level reaches the set level of the mixer 30, the powder bin 20 starts to discharge the material. The membrane separated casein powder is pumped into the mixer 30 and mixing begins. The stirring blade of the mixer 30 rotates at a speed of 2500r / min and the mixing time is 60min.

[0280] The casein solution prepared in step 1 has a dry matter content of 12.1 (g / 100g), protein (on a dry basis) of 86.4 (g / 100g), casein (as a percentage of protein) of 85.6 (g / 100g), and fat (on a dry basis) of 0.74 (g / 100g);

[0281] 2. Acid precipitation: The membrane-separated casein solution prepared in step 1 is poured into an acid precipitation tank 40, kept warm at 40°C, and a food-grade dilute hydrochloric acid solution is slowly added until the pH stabilizes at 4.1. During this process, the stirring collector 42 is continuously rotated counterclockwise at 60 rpm. When the precipitated casein particles gradually aggregate and grow to form casein micelles, the stirring collector 42 is adjusted to rotate counterclockwise at 20 rpm until the casein micelles are completely formed, and the acid precipitation step is completed.

[0282] The mass fraction of the dilute hydrochloric acid solution in step 2 is 12%, and it is prepared in advance in the acid tank 51 for standby use;

[0283] 3. Primary capture: After acid precipitation is completed, the stirring collector 42 is immediately adjusted to rotate clockwise at 120 rpm. The capture net unit 4211 rotates counterclockwise 90° under the action of resistance through the rotating part 4212 to overlap with the capture unit bracket 4213. The curved capture net 422 and the deformable capture net 421 together form a complete casein micelle precipitation and capture system. The casein micelle precipitation will be intercepted by the capture net under the action of centrifugal force and gradually form a filter layer. The capture process lasts for 2.5 minutes and ends, completing the primary capture of the casein micelle precipitation;

[0284] The spacing between the vertical supports of the capture unit bracket 4213 in step 2 is 113 mm;

[0285] In step 2, the meshes of the arc surface capturing net 422 and the deformable capturing net 421 are square hole structures with a side length of 4 mm.

[0286] 4. Primary diafiltration: After the casein micelle precipitation and capture are completed, the speed of the stirring collector 42 is maintained unchanged, and the clear liquid in the acid precipitation tank 40 is discharged into the by-product collection tank 60. After the clear liquid is emptied, 40°C RO water is added to the acid precipitation tank 4 to the set liquid level, and the stirring collector 42 is immediately adjusted to 20 rpm counterclockwise rotation. The diafiltration process is completed after 1.5 minutes;

[0287] 5. Secondary capture: After the diafiltration is completed, the stirring collector 42 is immediately adjusted to rotate clockwise at 120 rpm. The capture process lasts for 2.5 minutes and then ends, completing the secondary capture of casein micelle precipitation.

[0288] 6. Secondary diafiltration: After the secondary capture of casein micelle precipitation is completed, continue to maintain the rotation speed of the stirring collector 42 unchanged, and at the same time drain the clear liquid in the acid precipitation tank 40. After the clear liquid is emptied, add 40°C RO water to the acid precipitation tank 40 to the set liquid level, and immediately adjust the stirring collector 42 to 20 rpm counterclockwise rotation. The diafiltration process lasts for 1.5 minutes and then ends.

[0289] 7. Tertiary capture: After the secondary filtration is completed, the stirring collector 42 is immediately adjusted to rotate clockwise at 120 r / min. The tertiary capture process lasts for 2.5 minutes and then ends, completing the tertiary capture of casein micelle precipitation;

[0290] 8. Crushing: After the casein micelle precipitate is captured three times, the speed of the stirring collector 42 is maintained constant, and the clear liquid in the acid precipitation tank 40 is drained. After the clear liquid is drained, 40°C RO water is added to the acid precipitation tank 40 to the set liquid level. The stirring collector 42 is immediately adjusted to 140 r / min counterclockwise rotation. The casein micelle precipitate is dispersed and cut by the stirring collector 42 and evenly dispersed in the material system. The speed of the stirring collector 42 is maintained constant, and the material is continuously discharged into the colloid mill for sufficient crushing, and then pumped into the alkali dissolution tank 70 by the screw pump;

[0291] 9. Alkali dissolution: Keep the temperature at 40℃ and slowly add food-grade sodium hydroxide solution until the pH stabilizes at 7.5. The speed of the stirring paddle in the alkali dissolution tank is 2000r / min and the alkali dissolution time is 50min.

[0292] The mass fraction of the sodium hydroxide solution in step 9 is 12%, and it is prepared in advance in the alkali solution tank 52 for standby use;

[0293] 10. Sterilization: The sodium caseinate solution prepared in step 9 is pumped into the scraper sterilizer 80 through a screw pump to the temporary storage tank 90 and kept at 72°C for later use;

[0294] 11. Concentration and spray drying: The sterilized sodium caseinate solution is pumped into an evaporator for concentration and then spray dried to obtain the finished sodium caseinate product.

[0295] Example 2:

[0296] 1. Raw material dissolution: First, put the membrane separated casein powder into the powder bin 20. The RO water is heated to 55°C by the water supply unit 10 and enters the hot water tank 11 for temporary heat preservation. The hot water enters the mixer 30 from the hot water tank 11. When the hot water level reaches the set level of the mixer 30, the powder bin 20 starts to discharge the material. The membrane separated casein powder is pumped into the mixer 30 and mixing begins. The stirring blade of the mixer 30 rotates at a speed of 3500r / min and the mixing time is 30min.

[0297] The prepared casein in step 1 has a liquid dry matter content of 12.5 (g / 100g), protein (on a dry basis) of 86.2 (g / 100g), casein (as a percentage of protein) of 85.4 (g / 100g), and fat (on a dry basis) of 0.89 (g / 100g);

[0298] 2. Acid precipitation: The membrane-separated casein solution prepared in step 1 is poured into the acid precipitation tank 40, kept warm at 55°C, and food-grade dilute hydrochloric acid solution is slowly added until the pH stabilizes at 4.6. During this process, the stirring collector 42 is continuously rotated counterclockwise at 30 rpm. When the precipitated casein particles gradually aggregate and grow to form casein micelles, the stirring collector 42 is adjusted to rotate counterclockwise at 10 rpm until the casein micelles are completely formed, and the acid precipitation step is completed.

[0299] The mass fraction of the dilute hydrochloric acid solution in step 2 is 13%, and it is prepared in advance in the acid tank 51 for standby use;

[0300] 3. Primary capture: After acid precipitation is completed, the stirring collector 42 is immediately adjusted to rotate clockwise at 120 rpm. The capture net unit 4211 rotates counterclockwise 90° under the action of resistance through the rotating part 4212 to overlap with the capture unit bracket 4213. The curved capture net 422 and the deformable capture net 421 together form a complete casein micelle precipitation and capture system. The casein micelle precipitation will be intercepted by the capture net under the action of centrifugal force and gradually form a filter layer. The capture process lasts for 5 minutes and ends, completing the primary capture of the casein micelle precipitation;

[0301] The spacing between the vertical support rods of each set of capture unit brackets 4213 in step 2 is 248 millimeters (mm);

[0302] The meshes of the arc surface capturing net 422 and the deformable capturing net 421 in step 2 are square hole structures with a side length of 8 mm.

[0303] 4. Primary diafiltration: After the casein micelle precipitation and capture are completed, the speed of the stirring collector 42 is maintained unchanged, and the clear liquid in the acid precipitation tank 40 is discharged into the by-product collection tank 60. After the clear liquid is emptied, 55°C RO water is added to the acid precipitation tank 40 to the set liquid level. The stirring collector 4 is immediately adjusted to rotate counterclockwise at 10 rpm. The diafiltration process is completed after 3 minutes.

[0304] 5. Secondary capture: After the filtration is completed, the stirring collector 42 is immediately adjusted to 80 rpm clockwise rotation. The capture process lasts for 5 minutes and then ends, completing the secondary capture of casein micelle precipitation.

[0305] 6. Secondary diafiltration: After the secondary capture of casein micelle precipitation is completed, continue to maintain the rotation speed of the stirring collector 42 unchanged, and at the same time drain the clear liquid in the acid precipitation tank 40. After the clear liquid is emptied, add 55°C RO water to the acid precipitation tank 40 to the set liquid level, and immediately adjust the stirring collector 42 to 10 rpm counterclockwise rotation. The diafiltration process lasts for 3 minutes and then ends.

[0306] 7. Tertiary capture: After the secondary filtration is completed, the stirring collector 42 is immediately adjusted to 80 rpm clockwise rotation. The tertiary capture process lasts for 5 minutes and then ends, completing the tertiary capture of casein micelle precipitation.

[0307] 8. Crushing: After the casein micelle precipitation is captured three times, the speed of the stirring collector 42 is maintained unchanged, and the clear liquid in the acid precipitation tank 40 is drained. After the clear liquid is emptied, 55°C RO water is added to the acid precipitation tank 40 to the set liquid level. The stirring collector 42 is immediately adjusted to 90r / min counterclockwise rotation. The casein micelle precipitation is dispersed and cut by the stirring collector 42 and evenly dispersed in the material system. The speed of the stirring collector 42 is maintained unchanged, and the material is continuously discharged into the colloid mill for sufficient crushing, and then driven into the alkali dissolution tank 70 by the screw;

[0308] 9. Alkali dissolution: Keep the temperature at 55℃ and slowly add food-grade sodium hydroxide solution until the pH stabilizes at 7.0. The speed of the stirring paddle in the alkali dissolution tank is 3000r / min and the alkali dissolution time is 20min.

[0309] The mass fraction of the sodium hydroxide solution in step 9 is 13%, which is prepared in advance in the alkali solution tank 52;

[0310] 10. Sterilization: The sodium caseinate solution prepared in step 9 is pumped into the scraper sterilizer 80 through a screw pump to the insulation temporary storage tank 90 and kept at 75°C for later use;

[0311] 11. Concentration and spray drying: The sterilized sodium caseinate solution is pumped into an evaporator for concentration and then spray dried to obtain the finished sodium caseinate product.

[0312] Example 3:

[0313] 1. Raw material dissolution: First, put the membrane separated casein powder into the powder bin 20. The RO water is heated to 53°C by the water supply unit 10 and enters the hot water tank 11 for temporary insulation. The hot water enters the mixer 30 from the hot water tank 11. When the hot water level reaches the set level of the mixer 30, the powder bin 20 starts to discharge the material. The membrane separated casein powder is pumped into the mixer 30 and mixing begins. The stirring blade of the mixer 30 rotates at a speed of 3000r / min and the mixing time is 45min.

[0314] The casein solution prepared in step 1 has a dry matter content of 12.3 (g / 100g), protein (on a dry basis) of 86.7 (g / 100g), casein (as a percentage of protein) of 85.9 (g / 100g), and fat (on a dry basis) of 0.66 (g / 100g);

[0315] 2. Acid precipitation: The membrane separated casein solution prepared in step 1 is poured into (acid precipitation tank 40), kept warm at 50°C, and food-grade dilute hydrochloric acid solution is slowly added until the pH stabilizes at 4.4 and the acid addition is completed. During this process, the (stirring trap 42) is continuously rotated counterclockwise at 50 rpm. When the precipitated casein particles gradually aggregate and increase to form casein micelles, the (stirring trap 42) is adjusted to 15 rpm counterclockwise rotation until the casein micelles are fully formed, and the acid precipitation step is completed.

[0316] The mass fraction of the dilute hydrochloric acid solution in step 2 is 12.5%, which is prepared in advance by (acid tank 51) for standby use;

[0317] 3. Primary capture: After acid precipitation is completed, the stirring collector 42 is immediately adjusted to rotate clockwise at 100 rpm. The capture net unit 4211 rotates counterclockwise 90° under the action of resistance through the rotating part 4212 to overlap with the capture unit bracket 4213. The curved capture net 422 and the deformable capture net 421 together form a complete casein micelle precipitation and capture system. The casein micelle precipitation will be intercepted by the capture net under the action of centrifugal force and gradually form a filter layer. The capture process lasts for 3.5 minutes and ends, completing the primary capture of the casein micelle precipitation;

[0318] The spacing between the vertical supports of the capture unit bracket 4213 in step 2 is 186 millimeters (mm);

[0319] The mesh of the curved capture net 422 and the deformable capture net 421 described in step 2 is a square hole structure with a side length of 6 mm. 4. Primary diafiltration: After the casein micelle precipitation and capture are completed, continue to maintain the rotation speed of the stirring collector 42 unchanged, and at the same time, drain the clear liquid in the acid precipitation tank 40 into the by-product collection tank 60. After the clear liquid is emptied, 50°C RO water is added to the acid precipitation tank 40 to the set liquid level. The stirring collector 42 is immediately adjusted to 15 rpm counterclockwise rotation. The diafiltration process lasts for 2.2 minutes and ends.

[0320] 5. Secondary capture: After the diafiltration is completed, the stirring collector 42 is immediately adjusted to rotate clockwise at 100 rpm. The capture process lasts for 3.5 minutes and then ends, completing the secondary capture of casein micelle precipitation.

[0321] 6. Secondary diafiltration: After the secondary capture of casein micelle precipitation is completed, continue to maintain the rotation speed of the stirring collector 42 unchanged, and at the same time drain the clear liquid in the acid precipitation tank 40. After the clear liquid is emptied, add 50°C RO water to the acid precipitation tank to the set liquid level, and immediately adjust the stirring collector 42 to 15 rpm counterclockwise rotation. The diafiltration process lasts for 2.2 minutes and then ends.

[0322] 7. Tertiary capture: After the secondary filtration is completed, the stirring collector 42 is immediately adjusted to rotate clockwise at 100 rpm. The tertiary capture process lasts for 3.5 minutes and then ends, completing the tertiary capture of casein micelle precipitation.

[0323] 8. Crushing: After the casein micelle precipitation is captured three times, the speed of the stirring collector 42 is maintained unchanged, and the clear liquid in the acid precipitation tank 40 is drained. After the clear liquid is drained, 50°C RO water is added to the acid precipitation tank 40 to the set liquid level. The stirring collector 42 is immediately adjusted to 115 r / min counterclockwise rotation. The casein micelle precipitation is dispersed and cut by the stirring collector 42 and evenly dispersed in the material system. The speed of the stirring collector 42 is maintained unchanged, and the material is continuously discharged into the colloid mill for sufficient crushing, and then pumped into the alkali dissolution tank 70 by the screw pump;

[0324] 9. Alkali dissolution: Keep the temperature at 53℃ and slowly add food-grade sodium hydroxide solution until the pH stabilizes at 7.3. The speed of the stirring paddle in the alkali dissolution tank is 2500r / min and the alkali dissolution time is 35min.

[0325] The mass fraction of the sodium hydroxide solution in step 9 is 12.5%, which is prepared in advance in the alkali solution tank 52;

[0326] 10. Sterilization: pump the sodium caseinate solution prepared in step 3 into the scraper sterilizer 80 through a screw pump to the temporary storage tank 90 and keep it at 73°C for later use;

[0327] 11. Concentration and spray drying: The sterilized sodium caseinate solution is pumped into an evaporator for concentration and then spray dried to obtain the finished sodium caseinate product.

[0328] Example 4:

[0329] 1. Raw material preparation: directly use membrane separation casein solution for production, omitting the step of raw material dissolution;

[0330] The casein solution described in step 1 has a dry matter content of 12.2 (g / 100g), protein (on a dry basis) of 86.6 (g / 100g), casein (as a percentage of protein) of 85.2 (g / 100g), and fat (on a dry basis) of 0.74 (g / 100g);

[0331] 2. Acid precipitation: The membrane-separated casein solution in step 1 is poured into an acid precipitation tank 40, kept warm at 50°C, and a food-grade dilute hydrochloric acid solution is slowly added until the pH stabilizes at 4.4. During this process, the stirring collector 42 is continuously rotated counterclockwise at 50 rpm. When the precipitated casein particles gradually aggregate and grow to form casein micelles, the stirring collector 42 is adjusted to rotate counterclockwise at 15 rpm until the casein micelles are completely formed, and the acid precipitation step is completed.

[0332] The mass fraction of the dilute hydrochloric acid solution in step 2 is 12.5%, and it is prepared in advance in the acid tank 51 for standby use;

[0333] 3. Primary capture: After the acid precipitation is completed, the stirring collector 42 is immediately adjusted to rotate clockwise at 100 rpm. The capture net unit 4211 rotates counterclockwise 90° under the action of resistance through the rotating part 4212 and overlaps with the capture unit bracket 4213. The arc-surface capture net 422 and the deformable capture net 421 together form a complete casein micelle precipitation and capture system. The casein micelle precipitation will be intercepted by the capture net under the action of centrifugal force and gradually form a filter layer. The capture process lasts for 3.5 minutes and ends, completing the primary capture of the casein micelle precipitation;

[0334] In step 2, the spacing between the vertical support rods of each set of capture unit brackets 4213 is 180 mm;

[0335] In step 2, the meshes of the arc surface capturing net 422 and the deformable capturing net 421 are square hole structures with a side length of 6 mm.

[0336] 4. Primary diafiltration: After the casein micelle precipitation and capture are completed, the speed of the stirring collector 42 is maintained unchanged, and the clear liquid in the acid precipitation tank 40 is discharged into the by-product collection tank 60. After the clear liquid is emptied, 50°C RO water is added to the acid precipitation tank 40 to the set liquid level. The stirring collector 42 is immediately adjusted to rotate counterclockwise at 15 rpm. The diafiltration process is completed after 2.2 minutes.

[0337] 5. Secondary capture: After the diafiltration is completed, the stirring collector 42 is immediately adjusted to rotate clockwise at 100 rpm. The capture process lasts for 3.5 minutes and then ends, completing the secondary capture of casein micelle precipitation.

[0338] 6. Secondary diafiltration: After the secondary capture of casein micelle precipitation is completed, the speed of the stirring collector 42 is maintained unchanged, and the clear liquid in the acid precipitation tank 40 is drained. After the clear liquid is emptied, 50°C RO water is added to the acid precipitation tank 40 to the set liquid level. The stirring collector 42 is immediately adjusted to 15 rpm counterclockwise rotation. The diafiltration process lasts for 2.2 minutes and then ends.

[0339] 7. Tertiary capture: After the secondary filtration is completed, the stirring collector 42 is immediately adjusted to rotate clockwise at 100 rpm. The tertiary capture process lasts for 3.5 minutes and then ends, completing the tertiary capture of casein micelle precipitation.

[0340] 8. Crushing: After the casein micelle precipitation is captured three times, the speed of the stirring collector 42 is maintained constant, and the clear liquid in the acid precipitation tank 40 is drained. After the clear liquid is drained, 50°C RO water is added to the acid precipitation tank 40 to the set liquid level. The stirring collector 42 is immediately adjusted to 115 r / min counterclockwise rotation. The casein micelle precipitation is dispersed and cut by the stirring collector 42 and evenly dispersed in the material system. The speed of the stirring collector 42 is maintained constant, and the material is continuously discharged into the colloid mill for sufficient crushing, and then pumped into the alkali dissolution tank 70 by the screw pump;

[0341] 9. Alkali dissolution: Keep the temperature at 53℃ and slowly add food-grade sodium hydroxide solution until the pH stabilizes at 7.3. The speed of the stirring paddle in the alkali dissolution tank is 2500r / min and the alkali dissolution time is 35min.

[0342] The mass fraction of the sodium hydroxide solution in step 9 is 12.5%, which is prepared in advance in the alkali solution tank 52;

[0343] 10. Sterilization: The sodium caseinate solution prepared in step 9 is pumped into the scraper sterilizer 80 through a screw pump to the temporary storage tank 90 and kept at 73°C for later use;

[0344] 11. Concentration and spray drying: The sterilized sodium caseinate solution is pumped into an evaporator for concentration and then spray dried to obtain the finished sodium caseinate product.

[0345] Comparative Example

[0346] Comparative Example 1

[0347] The secondary capture and secondary diafiltration processes in Example 3 are omitted, and the remaining steps are the same as in Example 3.

[0348] Comparative Example 2

[0349] The preparation process is as follows:

[0350] 1. Qula crushing: Use air flow crusher to repeatedly crush the Qula raw materials and pass through 80 mesh sieve (particle size ≤ 180μm);

[0351] 2. Dissolution: material-liquid ratio 1:8 (w / v), water temperature 52±3°C, stirring speed 200 rpm, dissolution time 90-120 min;

[0352] 3. Acidification: Slowly add 1 mol HCl dropwise to adjust the pH to 4.6 ± 0.1;

[0353] 4. Insulation: Maintain the temperature at 45±3°C, let it stand for 40-60 minutes, and collect the precipitated casein micelle particles in batches;

[0354] 5. Horizontal screw centrifugation: Each batch of material is centrifuged at 2500-3000 rpm for 15 minutes, the supernatant is discarded, and the casein micelle particles after centrifugation are returned to the tank;

[0355] 6. Washing: Add RO water to the precipitate at a ratio of 1:2 (w / v) and stir for 10-20 minutes;

[0356] 7. Repeat centrifugation: centrifuge twice under the same conditions;

[0357] 8. Neutralization: add 2 mol NaOH solution dropwise, adjust the pH to 6.8-7.0, dissolve at 60±5°C, stir at 100-300 rpm, and stir for 60-90 min;

[0358] 9. Sterilization: 75℃ for 30s.

[0359] Test Case

[0360] Test Example 1 Comparison of sensory and physical and chemical indicators

[0361] The sensory and physical and chemical indicators were compared according to the relevant requirements of GB1886.212, and the results are shown in Table 1 below.

[0362] Table 1: Physical and chemical index results

[0363]

[0364] The sodium caseinate prepared in Examples 1-4 has a milky white appearance, a slight frankincense aroma, good powder fluidity, ash content ≤5%, protein ≥90%, fat ≤1.8%, and moisture ≤4%. All product indicators of Examples 1-4 are superior to the relevant requirements of GB1886.212-2016. Compared with the examples, the protein and ash content of Comparative Example 1 do not meet the relevant requirements of GB1886.212-2016, indicating that the capture and filtration methods in Examples 1-4 can effectively improve the quality of the sodium caseinate product. All product indicators of Examples 1-4 are superior to those of Comparative Example 2, indicating that the preparation method provided by the embodiments of the present invention is superior to the existing Qula preparation method and the resulting product is of better quality.

[0365] Test Example 2 Comparison of physical, chemical and microbiological indicators

[0366] The physical, chemical and microbiological control levels were compared and the results are shown in Table 2 below.

[0367] Table 2 Results of physical, chemical and microbiological indicators

[0368]

[0369]

[0370] Conclusion: As can be seen from the data in Table 2, the present technical solution adopts a unique preparation system, and the entire production process is completely closed and pipelined, thereby greatly reducing the risks of microbial growth, foreign matter introduction, chemical contamination, etc. The product indicators of Examples 1-4 are all better than those of Comparative Example 2.

[0371] Test Example 3: Comparison of production efficiency and material yield

[0372] The production efficiency and material yield (output rate) were compared, and the results are shown in Table 3 below.

[0373] Table 3 Production efficiency and material yield results

[0374]

[0375] Conclusion: The present invention adopts a unique acid precipitation, capture and filtration system. Through the original stirring and trapping design, the functions of material stirring and mixing, casein micelle precipitation and capture, water replenishment, filtration and crushing can be achieved in a single acid precipitation tank. Compared with the method prepared in Comparative Example 2, the methods prepared in Examples 1-4 avoid repeated switching of the casein micelles after acid precipitation between material tanks, and the single batch production time of the products prepared in Examples 1-4 is shortened by nearly 1 times compared with the product prepared in Comparative Example 2, and the material yield (output rate) is increased by 6% (Table 3).

[0376] Test Example 4 Application Characteristics Comparison

[0377] (1) Experimental methods

[0378] The comparison of the application characteristics of sodium caseinate is as follows:

[0379] 1. Wettability Test Method: Measure 50°C distilled water into a 500mL beaker. Place a pumping plate and stainless steel funnel above the beaker. Pour the weighed sample (sample to water mass ratio of 3:20) into the stainless steel cylinder with the pumping plate, making sure the surface of the milk powder is level. Gently and continuously remove the bottom plate (complete within approximately 2 seconds). Start a stopwatch as the bottom plate is removed. Stop the stopwatch when all samples are submerged in water and record the elapsed time. The shorter the wettability time, the better the sample's solubility.

[0380] 2. Emulsification Test Method: First, measure distilled water at a specific temperature of 50°C into a 500mL beaker. Pour the weighed sample (sample to water mass ratio of 3:20) into the beaker to prepare an emulsion. Then, place a certain volume (e.g., 10mL) into a centrifuge tube. Centrifuge (3000 rpm, 5 minutes) to accelerate stratification. Observe the stratification process and calculate the volume ratio of the supernatant to the precipitate. The smaller the ratio of the supernatant to the precipitate, the better the sample's emulsification.

[0381] 3. Foam Stability Test Method: Foam stability is measured by foam half-life. First, measure 50°C distilled water into a 500mL beaker. Pour the weighed sample (sample to water mass ratio of 3:20) into the beaker and blend using a high-speed homogenizer (1000 rpm, 2 minutes). Start a stopwatch and measure the time it takes for the foam volume to decay to 50% of its initial volume. The longer the foam volume half-life, the better the sample's foaming properties and the more stable the foam.

[0382] 4. Film-forming property test method: Refer to GB / T 1040 method. The greater the tensile breaking stress, the better the film-forming property of the sample.

[0383] (2) Experimental results

[0384] The results are shown in Table 4 below.

[0385] Table 4 Application characteristics results

[0386]

[0387] Conclusion: The preparation processes of Examples 1-4 are more gentle, with high control precision in each process step, low degree of partial denaturation of the protein structure, and significantly improved solubility, emulsification efficiency, foaming properties, and film-forming properties. Compared with the product prepared in Comparative Example 2, the products prepared in Examples 1-4 showed approximately 30% higher wettability (Table 4), approximately 40% higher emulsification, approximately 45% higher foam stability, and approximately 30% higher film-forming properties.

[0388] In summary, the present invention uses membrane-separated casein as raw material rather than Qula, and the membrane-separated casein is prepared through acid precipitation, stirring and capturing, filtration, crushing, alkali dissolution, spray drying and other steps. The sodium caseinate prepared by this process has a milky white appearance, a slight frankincense aroma, good powder fluidity, ash content ≤5%, protein ≥90%, fat ≤1.8%, moisture ≤4%, no total arsenic detected, no lead detected, total colony count ≤3000 (CFU / g), and no coliform group detected. All product indicators are better than the relevant requirements of GB1886.212-2016; the present invention adopts a unique preparation system, and the entire production process is completely sealed and pipelined. The invention adopts a unique acid precipitation, capture and washing system, and through the original stirring and collecting device design, it can realize the functions of material stirring and mixing, casein micelle precipitation and capture, water replenishment, washing and filtering, and crushing in a single acid precipitation tank, thereby avoiding the repeated switching of casein micelles between material tanks after acid precipitation. The process is simple, the operation difficulty is low, and the operation is easy to standardize, the production efficiency is greatly improved, and the yield is higher. The preparation process of the invention is more gentle, the control accuracy of each process link is high, the degree of denaturation of the protein structure of the product is low, and the solubility, emulsification efficiency, foaming and film-forming properties are significantly improved.

[0389] It should be noted that, although the technical solutions of the present invention are described with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0390] While various embodiments of the present invention have been described above, the above descriptions are intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing sodium caseinate, characterized in that: The raw material used in the method includes casein; the method includes: an acid precipitation step, adding an acid solution to the raw material to form a casein micelle dispersion; a capturing step of capturing the casein micelles in the casein micelle dispersion, wherein the capturing step is performed at least three times; In the alkali dissolution step, an alkali solution is added to the product obtained from the last capture.

2. The preparation method according to claim 1, characterized in that The casein is separated from the casein raw material by a membrane separation method.

3. The preparation method according to claim 1 or 2, characterized in that In the acid precipitation step, an acid solution is added to the raw material until the pH value is between 3.5 and 5.5; the acid precipitation step is carried out at a temperature not exceeding 60°C.

4. The preparation method according to any one of claims 1 to 3, characterized in that The time for each capture step does not exceed 10 minutes.

5. The preparation method according to any one of claims 1 to 4, characterized in that After each capturing step, a diafiltration step is further included, wherein the diafiltration step comprises diafiltration of the product obtained from each capturing in a solvent.

6. The preparation method according to any one of claims 1 to 5, characterized in that The diafiltration step is carried out at a temperature not exceeding 62°C.

7. The preparation method according to any one of claims 1 to 6, characterized in that Before the alkali dissolution step, a crushing step is also included, and the crushing step includes crushing the product obtained from the last capture.

8. The preparation method according to any one of claims 1 to 7, characterized in that The alkali dissolution step is carried out at a pH of 7-8; the time for the alkali dissolution does not exceed 60 minutes.

9. The preparation method according to any one of claims 1 to 8, characterized in that The method further comprises a post-processing step, wherein the post-processing step comprises at least one of sterilization, concentration and drying.

10. The preparation method according to any one of claims 1 to 9, characterized in that: The preparation method is carried out by using an industrialized sodium caseinate preparation system, wherein the preparation system comprises one or more acid precipitation tanks (40) and one or more alkali dissolution tanks (70). The acid precipitation tank (40) is connected to the alkali dissolution tank (70), The acid precipitation tank (40) comprises a tank body (41), a stirring collector (42), a stirring motor (43) and a stirring main shaft (44); the stirring collector (42) is arranged inside the tank body (41); the stirring collector (42) is connected to the stirring main shaft (44); the stirring motor (43) is connected to the stirring main shaft (44); the stirring motor (43) can drive the stirring collector (42) and the stirring main shaft (44) to rotate. The stirring collector (42) comprises a deformable collecting net (421) and a cambered collecting net (422), wherein the deformable collecting net (421) extends in the radial direction and the axial direction of the tank body (41), and the cambered collecting net (422) extends in the circumferential direction and the axial direction of the tank body (41). The deformable capturing net (421) comprises a plurality of capturing net units (4211), a plurality of rotating parts (4212) and a capturing unit bracket (4213); the capturing net units (4211) are rotatably connected to the capturing unit bracket (4213) via the rotating parts (4212); the rotating shaft of the rotating part (4212) extends along the axial direction or the axially parallel direction of the tank body (41), so that the plurality of capturing net units (4211) can change the liquid-facing area of ​​the deformable capturing net (421) when rotating around the rotating shaft. The plurality of capturing net units (4211) are arranged in a matrix on both sides of the stirring main shaft (44); Preferably, the acid precipitation step, the capturing step, the filtration step, and the crushing step are all performed in the acid precipitation tank (40).

11. Sodium caseinate, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 10.

12. Sodium caseinate according to claim 11, characterized in that The sodium caseinate has a protein content of not less than 89% and an ash content of not more than 5% per 100g of the sodium caseinate on a dry basis.

13. Sodium caseinate according to claim 11 or 12, characterized in that The sodium caseinate has a moisture content of less than 3% per 100g of the sodium caseinate on a dry basis; and the pH of the sodium caseinate is 6-7.

5.

14. A product, characterized in that The product comprises sodium caseinate prepared according to the preparation method according to any one of claims 1 to 10, or sodium caseinate according to any one of claims 11 to 13, and any one or more of the following ingredients: plant product ingredients, animal meat product ingredients, animal dairy product ingredients, functional additives and any acceptable excipients.

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