A method for separating alpha-lactalbumin and beta-lactoglobulin

Abstract

The present invention discloses a method for separating α-lactalbumin and β-lactoglobulin, and belongs to the technical field of dairy product processing. The method comprises the following steps: Step 1: Degreasing a milk-based raw material to obtain skimmed milk; Step 2: Microfiltration of the skimmed milk, the permeate is whey containing α-lactalbumin, β-lactoglobulin components, lactose and other components. Step 3: The permeate is subjected to hydrated calcium ion-assisted ultrafiltration treatment to remove lactose and minerals in the whey, and Step 4: Two-phase aqueous extraction treatment is performed to achieve separation of α-lactalbumin and β-lactoglobulin. Step 5: The upper phase and the lower phase are respectively subjected to hydrated calcium ion-assisted ultrafiltration treatment and electrodialysis technology desalination, and α-lactalbumin and β-lactoglobulin are concentrated. The method improves the utilization rate of milk and dairy products and the economic value of the treatment process, reduces production costs, is convenient for continuous operation, and is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of dairy product processing, and in particular relates to a method for separating alpha-lactalbumin and beta-lactoglobulin. Background Art

[0002] Whey contains a variety of biologically active substances with rich nutritional value, such as whey protein, lactoferrin, α-lactalbumin, β-lactoglobulin, etc., which have extremely high utilization value. Among them, α-lactalbumin and β-lactoglobulin account for more than 80% of whey protein and are the two proteins with the highest content. Whey is widely used in infant formula milk powder. α-lactalbumin is an important added ingredient with outstanding activities such as promoting lactose secretion, anti-cancer and anti-inflammatory. Increasing its content helps to improve the nutritional value of formula milk powder; while β-lactoglobulin usually needs to be removed from formula milk powder due to its potential allergenicity. At the same time, β-lactoglobulin has affinity for biologically active substances such as vitamins, fatty acids and polyphenols, and is one of the most widely studied ligand-binding proteins in food proteins. Therefore, efficient separation of α-lactalbumin and β-lactoglobulin in raw milk and its products while maintaining their biological activity is an important prerequisite for achieving precise nutrition, safety assurance of infant formula milk powder and deep processing of the dairy industry.

[0003] In order to achieve efficient separation of α-lactalbumin and β-lactoglobulin, it is first necessary to separate and concentrate the whey components in the raw milk. Modern membrane separation technology is widely used in milk and dairy products, and is subdivided into technical fields such as microfiltration, ultrafiltration, nanofiltration, and electrodialysis. However, membrane separation technology has problems of low product purity and high risk of biological contamination in the fine separation of α-lactalbumin and β-lactoglobulin. The Chinese patent application number CN201410534492.2 discloses a preparation method and product of α-lactalbumin powder and / or β-lactoglobulin powder, which achieves the separation of α-lactalbumin and β-lactoglobulin by combining 100 kDa and 30 kDa ultrafiltration membranes. However, due to the close molecular weight of the two proteins, the product purity of this method is low and the efficiency is low. It is worth noting that the transmembrane pressure in the membrane separation process is the driving force for molecular screening, and under the action of tangential shear stress and intra-membrane shear stress, milk protein will undergo irreversible unfolding, which is mainly manifested as changes in the secondary structure, breaking of disulfide bonds, and exposure of hydrophobic groups, thus bringing negative impacts on the biological activity of whey protein.

[0004] Secondly, after obtaining the high-concentration whey component, other means are needed to purify α-lactalbumin and β-lactoglobulin. The molecular weights of α-lactalbumin and β-lactoglobulin are similar. The methods for obtaining these two proteins in the laboratory usually include laboratory techniques such as gel chromatography, ion chromatography, and reverse chromatography, but the low yield of such methods is not conducive to factory production. Other separation techniques such as salting out and isoelectric precipitation have precise requirements for the pH of the solution, are complicated to operate, and have low product purity. The two-phase aqueous extraction method is simple to operate and can be operated continuously. It can achieve rapid and efficient separation of α-lactalbumin and β-lactoglobulin by utilizing the differences in protein molecular weight and its hydration characteristics in the solution. The Chinese patent with application number CN201510744212.5 discloses a method for cyclic large-scale separation of β-lactoglobulin, which achieves the separation of β-lactoglobulin by using polyvinyl pyrrolidone / sodium citrate two-phase aqueous extraction on raw milk, but the method does not classify and process α-lactalbumin, lactose, and mineral elements through reasonable means. Chinese patent application number CN201310460499.X discloses a method for separating milk-derived whey protein using a PEG / phosphate aqueous two-phase system. This method effectively separates α-lactalbumin and β-lactoglobulin, but lactose and mineral elements in the whey are not further separated, and the product purity of α-lactalbumin and β-lactoglobulin is low. Summary of the invention

[0005] The object of the present invention is to provide a method for separating α-lactalbumin and β-lactoglobulin, so as to solve the problems existing in the current separation process of α-lactalbumin and β-lactoglobulin: low separation efficiency, protein variability and low product purity.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for separating α-lactalbumin and β-lactoglobulin comprises the following steps:

[0008] Step 1: Degreasing the milk-based raw material to obtain skimmed milk;

[0009] Step 2: microfiltration of skimmed milk, the permeate is whey including α-lactalbumin, β-lactoglobulin components, lactose and minerals;

[0010] Step 3: The permeate in step 2 is subjected to a hydrated calcium ion-assisted ultrafiltration treatment to remove lactose and minerals in the whey. The retentate in this step is a concentrated solution containing α-lactalbumin and β-lactoglobulin components;

[0011] Step 4: performing a two-phase aqueous extraction treatment on the concentrated solution in step 3 to separate and obtain solutions containing α-lactalbumin and β-lactoglobulin respectively;

[0012] Step 5: The upper phase and lower phase solutions are subjected to hydrated calcium ion-assisted ultrafiltration and electrodialysis technology desalination, respectively, to concentrate α-lactalbumin and β-lactoglobulin.

[0013] In some possible implementations, the dairy-based raw material includes at least one of milk and dairy products.

[0014] In some possible implementations, the milk includes fresh milk; the fresh milk includes at least one of cow's milk, goat's milk, camel's milk, horse's milk, donkey's milk and yak's milk;

[0015] The dairy product comprises at least one of whey liquid, whole milk powder, skim milk powder, whey powder and whey protein powder.

[0016] In some possible implementations, the fat content after defatting in step 1 is less than 0.1%.

[0017] In some possible implementations, the degreasing process uses a centrifugal separation method.

[0018] In some possible implementations, the casein content in the permeate after microfiltration treatment in step 2 is less than 3%.

[0019] In some possible implementations, the ceramic ultrafiltration membrane used in the hydrated calcium ion-assisted ultrafiltration treatment has a molecular weight cutoff of 10 kDa and a transmembrane pressure of 0.08-0.10 MPa.

[0020] In some possible implementations, the volume ratio of the polyethylene glycol solution to the KH2PO4 solution in the aqueous two-phase extraction treatment system in step 4 is 1 / 1; wherein the mass percentage concentration of the polyethylene glycol solution is 30%, and the mass percentage concentration of the KH2PO4 solution is 20%.

[0021] In some possible implementations, a standard calcium chloride solution is used to adjust the ion concentration in the hydrated calcium ion-assisted ultrafiltration process, and the calcium ion concentration of the solution is adjusted to 5 mmol / L-20 mmol / L.

[0022] In some possible implementations, the electrodialysis desalination treatment uses a homogeneous electrodialysis membrane, the conductivity is monitored during the process, and the dialysis is stopped when the conductivity is 0.12-0.15 mS / cm.

[0023] Beneficial effects of the present invention:

[0024] The invention aims at efficiently separating and maintaining the activity of whey protein, avoids introducing acid treatment and heat treatment procedures, and uses hydrated ions to regulate the ultrafiltration process on the basis of conventional operations of centrifugal defatting of milk raw materials and whey separation, so as to promote the formation of an ion water molecule layer around the protein and on the membrane surface, reduce protein structure damage caused by tangential shear stress and intra-membrane shear stress, ensure the structural stability of the whey protein, and further realize the purification of active alpha-lactalbumin and beta-lactoglobulin in the whey protein through two-phase aqueous extraction.

[0025] In the method for separating α-lactalbumin and β-lactoglobulin components in milk and dairy products disclosed in the present invention, the components of milk and dairy products are subjected to exclusion-type separation and extraction to obtain α-lactalbumin and β-lactoglobulin components with high economic value, thereby improving the utilization rate of milk and dairy products and retaining the biological activity of the components.

[0026] The method for separating α-lactalbumin and β-lactoglobulin components in milk and dairy products of the present invention does not require excessive processing and can be directly used to prepare formula dairy products, thereby improving production efficiency and enhancing the nutritional value of milk-based raw materials.

[0027] The method of the present invention for separating α-lactalbumin and β-lactoglobulin components in milk and dairy products can separate a single raw material or a plurality of mixed raw materials, extract various components of the milk-based raw materials, and achieve the advantages of maintaining active ingredients, maximizing product yield, improving production efficiency, and improving cost performance.

[0028] In the method for separating α-lactalbumin and β-lactoglobulin components in milk and dairy products disclosed in the present invention, by adding inorganic hydrated salt ions and adjusting their concentrations in the process, it is helpful to maintain the structural stability of milk protein molecules during the membrane filtration process, improve the utilization rate of milk and dairy products and the economic value of the treatment process, reduce production costs, facilitate continuous operation, and be suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the accompanying drawings.

[0030] Figure 1 The present invention is a flow chart for separating α-lactalbumin and β-lactoglobulin. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In order to improve the utilization rate of milk and dairy products and the economic value of the processing technology, reduce production costs, and facilitate continuous operation, it is suitable for industrial production. For the convenience of explanation, the following embodiments are described by taking a method for separating α-lactalbumin and β-lactoglobulin as an example.

[0033] A method for separating α-lactalbumin and β-lactoglobulin comprises the following steps:

[0034] Step 1: Degrease the milk-based raw materials to obtain skimmed milk; the skimmed milk enters the next processing stage, and the milk fat can be further processed into butter or used as a raw material for cream products.

[0035] Step 2: Microfiltration is performed on the skimmed milk, the permeate is whey containing α-lactalbumin, β-lactoglobulin, lactose, minerals and other components, and the retentate is milk base containing casein components.

[0036] Step 3: The permeate in step 2 is subjected to a hydrated calcium ion-assisted ultrafiltration treatment to remove lactose and minerals in the whey. The retentate in this step is a concentrated solution of α-lactalbumin and β-lactoglobulin components.

[0037] Step 4: performing a two-phase aqueous extraction treatment on the concentrated solution in step 3 to separate α-lactalbumin and β-lactoglobulin.

[0038] Step 5: The upper phase and lower phase solutions are subjected to hydrated calcium ion-assisted ultrafiltration and electrodialysis technology desalination, respectively, to concentrate α-lactalbumin and β-lactoglobulin.

[0039] In some specific embodiments, the dairy-based raw material includes at least one of milk and dairy products;

[0040] In some specific embodiments, the milk comprises raw milk;

[0041] The dairy product comprises at least one of whey liquid, whole milk powder, skim milk powder, whey powder and whey protein powder;

[0042] The fresh milk includes at least one of cow's milk, goat's milk, camel's milk, horse's milk, donkey's milk and yak's milk.

[0043] In some specific embodiments, the degreasing treatment in step 1 adopts a centrifugal separation method, and the fat content after degreasing is less than 0.1% (W / W). Too high a fat content will cause instability of the system in the subsequent separation process, affecting the efficiency and separation purity of the separation process; controlling the fat content too low is strict for the centrifugal separation conditions. After multiple tests, the centrifugal speed is adjusted to 6000-7000 r / min, the time is 25-30 min, and the temperature is 50-55°C, which can better control the fat content after degreasing. In the exemplary example, the centrifugal speed can be 6000 r / min, 6500 r / min, 7000 r / min, etc., which are typical but non-restrictive speeds or a range between any two speeds, and the temperature can be 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, etc., which are typical but non-restrictive temperatures or a range between any two temperatures. Under such conditions, the stability of the system can be improved, thereby improving the separation efficiency and purity.

[0044] In some specific embodiments, the casein content in the permeate after the microfiltration treatment in step 2 is less than 3%; too high a casein content will affect the separation and purification process of α-lactalbumin and β-lactoglobulin, affect the purity and quality of the protein, and make the separation process more complicated and difficult. Controlling the casein content too low places strict demands on the conditions in the microfiltration process. The ceramic microfiltration membrane pore size selected in the embodiments of this application is 0.1-0.2 µm, and the microfiltration transmembrane pressure is 0.07-0.09 MPa to regulate the casein content in the permeate.

[0045] In some specific embodiments, the volume ratio of the polyethylene glycol solution to the KH2PO4 solution in the two-phase aqueous extraction treatment system in step 4 is 1 / 1; wherein the mass percentage concentration of the polyethylene glycol solution is 30%, and the mass percentage concentration of the KH2PO4 solution is 20%. α-lactalbumin is a hydrophobic protein, and β-lactoglobulin is a hydrophilic protein. The extraction rate of α-lactalbumin and β-lactoglobulin is improved by the two-phase aqueous system.

[0046] In some specific embodiments, the ceramic ultrafiltration membrane used in the hydrated calcium ion-assisted ultrafiltration treatment in step three and step five has a molecular weight cutoff of 10 kDa.

[0047] In some specific embodiments, the hydrated calcium ion-assisted ultrafiltration treatment in step 3 and step 5 uses a calcium chloride (CaCl2) standard solution (1 mol / L) to adjust the ion concentration, and adjusts the solution calcium ion concentration to 5 mmol / L-20mmol / L. The calcium ion concentration in the embodiment can be 5mmol / L, 10mmol / L, 15mmol / L, 20mmol / L and other typical but non-limiting concentrations or a range between any two concentrations. Within this range, the Ca in the present invention 2+The role of maintaining protein structure stability is mainly reflected in: using the hydration of metal ions to form hydrated Ca 2+ , proteins attract hydrated Ca in solution under the action of electrostatic field 2+ , forming Ca on the protein surface 2+ Ionized water molecule layer; similar to protein, Ca is attached to the surface of the ultrafiltration membrane 2+ Ionized water molecule layer; Ca 2+ The formation of the ion layer strengthens the hydration repulsion between proteins and between proteins and membranes. This ionized water molecule layer plays a role similar to that of a "lubricant", reducing the tangential shear stress and intra-membrane shear stress of the ultrafiltration process, thereby helping to maintain the stability of the protein structure.

[0048] In some specific embodiments, the electrodialysis desalination treatment uses a homogeneous electrodialysis membrane, monitors the conductivity during the process, monitors the change of the dissolved matter content in real time, and stops the dialysis when the conductivity is 0.12-0.15 mS / cm. The potential difference is used as the driving force, the temperature is 25-30 °C, the voltage is 20-22 V, and the current is 0.1-0.2A.

[0049] Example 1

[0050] Reference Figure 1 The flowchart shown is used to separate α-lactalbumin and β-lactoglobulin in milk, and specifically comprises the following steps:

[0051] Step 1: Degreasing of milk-based raw materials: Fresh milk is preheated to 50°C, and the fat is separated by centrifugation to obtain skimmed milk. The centrifugal speed in this step is 7000 r / min, and the time is 30 min.

[0052] Step 2: Microfiltration of skimmed milk: Skimmed milk contains a milk base with casein as the main component and whey with α-lactalbumin and β-lactoglobulin as the main components. Microfiltration is used to separate the milk base and whey of skimmed milk. The pore size of the ceramic microfiltration membrane is 0.1 µm, and the transmembrane pressure is 0.09 MPa. The permeate is whey containing α-lactalbumin, β-lactoglobulin components, lactose, minerals and other components, and the retentate is a milk base containing casein components. In order to improve the removal rate of whey components in the retentate, the microfiltration process lasts for 30 minutes, and distilled water is replenished to the microfiltration tank, and repeated three times.

[0053] Step 3: Perform multi-ion controlled ultrafiltration on the whey permeate: remove lactose and minerals from the whey. The retentate in this step is a concentrate of α-lactalbumin and β-lactoglobulin components. An ultrafiltration membrane with a molecular weight cutoff of 10 kDa is selected, the transmembrane pressure is set to 0.10 MPa, and the ion concentration is adjusted using a calcium chloride (CaCl2) standard solution (1 mol / L). The calcium ion concentration of the solution is adjusted to 5 mmol / L. When the permeate volume is 90% of the initial volume, ultrafiltration is stopped to achieve the concentration of α-lactalbumin and β-lactoglobulin components in the whey.

[0054] Step 4: Perform two-phase aqueous extraction on the whey concentrate: the volume ratio of polyethylene glycol (PEG1500) solution to KH2PO4 solution is 1 / 1; wherein the mass percentage concentration of the polyethylene glycol solution is 30%, and the mass percentage concentration of the KH2PO4 solution is 20%. The volume ratio of the extract to the whey is 5:1. Stir and mix for 10 min, centrifuge (3000 r / min) for 30 min to separate the copolymer phase and the phosphate phase, the upper layer is the copolymer phase containing α-lactalbumin, and the lower layer is the phosphate phase containing β-lactoglobulin.

[0055] Step 5: The upper phase and lower phase solutions are subjected to ultrafiltration and electrodialysis treatment respectively: the upper and lower phase liquids are subjected to ultrafiltration through ceramic ultrafiltration membranes (molecular weight cutoff is 10 kDa), the calcium ion concentration during ultrafiltration is 5 mmol / L, the transmembrane pressure is 0.10 MPa, and the ultrafiltration is stopped when the permeate volume is 95% of the initial volume. The retentate is a concentrated solution containing α-lactalbumin or β-lactoglobulin, and α-lactalbumin and β-lactoglobulin are concentrated. The permeate is a copolymer solution or a KH2PO4 solution, and the concentration is further adjusted for recycling.

[0056] The concentrate was subjected to electrodialysis treatment, using a homogeneous electrodialysis membrane, with potential difference as the driving force, temperature 30 °C, voltage 20V, current 0.1A, and conductivity was monitored during the process. Dialysis was stopped when the conductivity was 0.12-0.15 mS / cm. The dialysis product was freeze-dried and the yield was calculated; the proportion of active protein was detected by saturated sodium chloride precipitation method.

[0057] Example 2

[0058] The difference between this embodiment and embodiment 1 is that the calcium ion concentration in step 2 and step 5 is adjusted to 10 mmol / L, and the other raw materials and preparation process remain the same as those in embodiment 1.

[0059] Example 3

[0060] The difference between this embodiment and embodiment 1 is that the calcium ion concentration in step 2 and step 5 is adjusted to 15 mmol / L, and the other raw materials and preparation process remain the same as those in embodiment 1.

[0061] Example 4

[0062] The difference between this embodiment and embodiment 1 is that the calcium ion concentration in step 2 and step 5 is adjusted to 20 mmol / L, and the other raw materials and preparation process remain the same as those in embodiment 1.

[0063] Example 5

[0064] The difference between this embodiment and embodiment 1 is that in the ultrafiltration treatment of step 2 and step 5, no calcium chloride solution is used to adjust the calcium ion concentration in the ultrafiltration system;

[0065] Specific:

[0066] Step 3: Perform multi-ion controlled ultrafiltration on the whey permeate: remove lactose and minerals from the whey. The retentate in this step is a concentrate of α-lactalbumin and β-lactoglobulin components. Use an ultrafiltration membrane with a molecular weight cutoff of 10 kDa, set the transmembrane pressure to 0.10 MPa, and stop ultrafiltration when the permeate volume is 90% of the initial volume to achieve the concentration of α-lactalbumin and β-lactoglobulin components in the whey.

[0067] Step 5: The upper phase and lower phase solutions are subjected to ultrafiltration and electrodialysis treatment respectively: the upper and lower phase liquids are subjected to ultrafiltration through ceramic ultrafiltration membranes (molecular weight cutoff of 10 kDa), the transmembrane pressure is 0.10 MPa, and the ultrafiltration is stopped when the permeate volume is 95% of the initial volume. The retentate is a concentrated solution containing α-lactalbumin or β-lactoglobulin, and α-lactalbumin and β-lactoglobulin are concentrated. The permeate is a copolymer solution or a KH2PO4 solution, and the concentration is further adjusted for recycling.

[0068] The concentrate was subjected to electrodialysis treatment, using a homogeneous electrodialysis membrane, with potential difference as the driving force, temperature 30 °C, voltage 20V, current 0.1A, and conductivity was monitored during the process. Dialysis was stopped when the conductivity was 0.12-0.15 mS / cm. The dialysis product was freeze-dried and the yield was calculated; the proportion of active protein was detected by saturated sodium chloride precipitation method.

[0069] The other parameters were the same as those in Example 3. Ultrafiltration was stopped when the permeate volume was 90% of the initial volume to achieve the concentration of α-lactalbumin and β-lactoglobulin components in whey. The other raw materials and preparation process were the same as those in Example 1.

[0070] Example 6

[0071] Compared with Example 1, the fresh cow's milk in this example is replaced with fresh goat's milk, and the other raw materials and preparation process remain the same as those in Example 3.

[0072] The results corresponding to Example 1 to Example 6 are recorded, as shown in Table 1:

[0073] Table 1

[0074]

[0075] As can be seen from Table 1, there is a large difference in the yield of α-lactalbumin and β-lactoglobulin between Example 1 and Example 6, indicating that there are differences in the whey protein composition of cow's milk and goat's milk, especially in the content and ratio of α-lactalbumin and β-lactoglobulin. Analyzed from the ratio of active protein, Example 5 did not perform hydration salt ion regulation during the ultrafiltration separation of whey protein, resulting in changes in the secondary structure of some whey proteins, thus quickly forming a precipitate and precipitating in a saturated sodium chloride system; and by comparing Examples 1, 2, 3, and 4, it was found that different calcium ion concentrations had different protective effects on active proteins during ultrafiltration, wherein the calcium ion concentration in Example 3 was 15 mmol / L, which had the best protein activity protection effect.

[0076] In general, the method for separating the components in milk and dairy products proposed in the present invention improves the utilization rate of milk and dairy products by separating and extracting the components of milk and dairy products, and retains the biological activity of various components. It does not require excessive processing and can be directly used to prepare dairy products, thereby improving production efficiency and reducing production costs. It is convenient for continuous operation and is suitable for industrial production.

[0077] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0078] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for separating α-lactalbumin and β-lactoglobulin, characterized in that: The steps include: Step 1: Degreasing the milk-based raw material to obtain skimmed milk; Step 2: microfiltration of skimmed milk, the permeate is whey including α-lactalbumin, β-lactoglobulin components, lactose and minerals; Step 3: The permeate in step 2 is subjected to a hydrated calcium ion-assisted ultrafiltration treatment to remove lactose and minerals in the whey. The retentate in this step is a concentrated solution containing α-lactalbumin and β-lactoglobulin components; Step 4: performing a two-phase aqueous extraction process on the concentrated solution in step 3 to obtain an upper phase solution and a lower phase solution; Step 5: The upper phase solution is subjected to hydrated calcium ion-assisted ultrafiltration treatment and electrodialysis technology desalination to obtain α-lactalbumin; the lower phase solution is subjected to hydrated calcium ion-assisted ultrafiltration treatment and electrodialysis technology desalination to obtain β-lactoglobulin; In the hydrated calcium ion-assisted ultrafiltration treatment, a calcium chloride standard solution is used to adjust the ion concentration, and the calcium ion concentration of the solution is adjusted to 5 mmol / L-20 mmol / L.

2. A method for separating α-lactalbumin and β-lactoglobulin according to claim 1, characterized in that: The milk-based raw material includes at least one of milk and dairy products.

3. A method for separating α-lactalbumin and β-lactoglobulin according to claim 2, characterized in that: The milk-based raw materials include milk and dairy products; The milk includes fresh milk; the fresh milk includes at least one of cow's milk, goat's milk, camel's milk, horse's milk, donkey's milk and yak's milk; the dairy product includes at least one of whey liquid, whole milk powder, skim milk powder, whey powder and whey protein powder.

4. The method for separating α-lactalbumin and β-lactoglobulin according to claim 1, characterized in that: The fat content after defatting in step 1 is less than 0.1%.

5. The method for separating α-lactalbumin and β-lactoglobulin according to claim 1, characterized in that: The degreasing treatment adopts a centrifugal separation method.

6. The method for separating α-lactalbumin and β-lactoglobulin according to claim 1, characterized in that: The casein content in the permeate after microfiltration treatment in step 2 is less than 3%.

7. The method for separating α-lactalbumin and β-lactoglobulin according to claim 1, characterized in that: The ceramic ultrafiltration membrane used in the hydrated calcium ion-assisted ultrafiltration treatment has a molecular weight cutoff of 10 kDa.

8. The method for separating α-lactalbumin and β-lactoglobulin according to claim 1, characterized in that: In step 4, the volume ratio of the polyethylene glycol solution to the KH2PO4 solution in the aqueous two-phase extraction treatment system is 1 / 1; wherein the mass percentage concentration of the polyethylene glycol solution is 30%, and the mass percentage concentration of the KH2PO4 solution is 20%.

9. The method for separating α-lactalbumin and β-lactoglobulin according to claim 1, characterized in that: The electrodialysis technology desalination treatment adopts a homogeneous electrodialysis membrane, monitors the conductivity during the process, and stops the dialysis when the conductivity is 0.12-0.15 mS / cm.

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