阅读说明：本技术 一种半乳糖葡萄糖混合物的制备方法 (Preparation method of galactose glucose mixture ) 是由 李伟 王彦平 孟蝶 巴根纳 樊启程 付永 于 2019-10-12 设计创作，主要内容包括：本发明提供了一种半乳糖葡萄糖混合物的制备方法,包括以下步骤：(1)以牛奶为原料,制备粗乳糖液；(2)将粗乳糖液进行脱盐脱色,获得精制乳糖液；(3)将β-半乳糖苷酶加入精制乳糖液中,使乳糖进行水解；(4)进行真空浓缩或RO膜浓缩,获得精制浓缩的半乳糖葡萄糖混合物。其中,乳糖的水解率达到95％以上,所制得的混合物中半乳糖含量大于22％,葡萄糖含量大于22％,乳糖含量小于5.0％,总固形物大于55％,灰分小于总固形物的0.3％。(The invention provides a preparation method of a galactose glucose mixture, which comprises the following steps: (1) taking milk as a raw material, and preparing a crude milk sugar solution; (2) desalting and decoloring the crude lactose liquid to obtain refined lactose liquid; (3) adding beta-galactosidase into refined lactose liquid to hydrolyze lactose; (4) vacuum concentrating or concentrating with RO membrane to obtain refined and concentrated galactose glucose mixture. Wherein, the hydrolysis rate of lactose is more than 95%, the galactose content in the prepared mixture is more than 22%, the glucose content is more than 22%, the lactose content is less than 5.0%, the total solid content is more than 55%, and the ash content is less than 0.3% of the total solid content.)

1. A preparation method of a galactose glucose mixture is characterized by comprising the following steps:

(1) taking milk as a raw material, and preparing a crude milk sugar solution; preferably, the milk is skim milk;

(2) desalting and decoloring the crude lactose liquid to obtain refined lactose liquid;

(3) adding beta-galactosidase into refined lactose liquid to hydrolyze lactose;

(4) vacuum concentrating or concentrating with RO membrane to obtain refined and concentrated galactose glucose mixture.

2. The method according to claim 1, wherein in the step (1), when the milk is fresh milk, whole milk, half milk, reconstituted milk, nonreactive milk, buffalo milk, the skim milk is obtained by filtration, impurity removal and centrifugal separation, and then pasteurized and ultrafiltered, preferably, the ultrafiltration membrane has a pore size of 0.01 μm to 0.05 μm.

3. The method according to claim 1, wherein the step (2) comprises the steps of:

a. and (4) nanofiltration: preferably, the aperture of the nanofiltration membrane is 0.001-0.002 μm, and the membrane pressure is 10-15 bar;

b. cation exchange: passing lactose solution through cation exchange resin, preferably the pore diameter of the resin is 0.5mm-1.0 mm;

c. electrodialysis: under the action of an external direct current electric field, ions in the lactose liquid are selectively permeated and separated by an ion exchange membrane;

d. anion exchange: passing lactose solution through anion exchange resin, preferably the pore diameter of the anion exchange resin is 0.1mm-0.5 mm;

e. and (5) adsorbing by using activated carbon.

4. The method of claim 1, wherein the β -galactosidase is derived from Kluyveromyces lactis (Kluyveromyces lactis).

5. The method of claim 1, wherein the hydrolysis temperature is 35-45 ℃.

6. The method of claim 1, wherein the hydrolysis is performed at a pH in the range of 5.0 to 7.0.

7. The method according to claim 1, wherein the vacuum concentration is carried out under a vacuum degree of-0.7 to-0.8 bar and at a temperature of 50 to 70 ℃.

8. The production method according to claim 1, wherein the pore diameter of the RO membrane is 1.0 to 5.0 nm.

9. The method of claim 1, further comprising a step (5) of sterilizing and enzyme-inactivating after the step (4), wherein the refined and concentrated galactose glucose mixture is pasteurized and enzyme-inactivated, preferably at a temperature of 85-95 ℃ for 15-30 s; more preferably, a drying step is included after step (5).

10. A galactose and glucose mixture (preferably liquid or powder) prepared by the preparation method according to any one of claims 1 to 9.

Technical Field

The invention relates to a lactose hydrolysis technology, in particular to a method for preparing a galactose and glucose mixture from lactose.

Background

The lactose liquid is the main component of whey liquid, cow milk or cow milk ultrafiltration permeate liquid, the crude lactose liquid usually contains whey protein, milk mineral salt and carotenoid, the sweetness of lactose is low, the lactose is not easy to be absorbed and utilized by adults, if the lactose is directly applied to liquid dairy products to replace cane sugar or syrup, the lactose is easy to crystallize and cause lactose intolerance, and meanwhile, the influence of the milk mineral salt, particularly sodium and potassium, on the taste and the addition amount of the product is large. If the lactose liquid is directly discharged, the lactose discharging and treating cost is high and the environmental pollution is serious because the biological oxygen demand is high.

The lactose hydrolysis technology mainly comprises an acid hydrolysis method and an enzyme hydrolysis method at present. The acid hydrolysis method has quick reaction and easy browning; the enzymatic hydrolysis method has the advantages of few side reactions, mild conditions and specific reaction. No relevant process for preparing a high-concentration refined galactose glucose mixture by hydrolyzing lactose liquid with lactase is found at present.

Therefore, the lactose is hydrolyzed into a mixture of galactose and glucose with high concentration and high purity by using a lactose hydrolysis process technology, and then the mixture is directly applied to a liquid dairy product or is processed into powdered sugar after being refined and dried. Wherein in the hydrolysate, glucose is the energy source of metabolism of each organ of human body, galactose is the structural component of brain and mucosa tissue of human body, and the rest lactose can play a certain role in nutrition and health care.

Disclosure of Invention

The main object of the present invention is to provide a process for the preparation of a galactose glucose mixture product of high concentration and purity, the components of the obtained product being galactose and glucose and traces of lactose, the mass of the other trace ashes being less than 0.3% of the total dry matter, said product being applicable in different food fields.

Galactose and glucose are both monosaccharides, and therefore, the galactose and glucose are small in molecules, high in concentration and viscosity and difficult to desalt, refine and concentrate, so that a galactose and glucose mixture with high concentration is difficult to obtain. The invention adopts a new process technology to process the crude lactose liquid separated from milk into high-concentration high-purity galactose glucose mixed liquid or galactose glucose mixed powder.

Specifically, the invention adopts a refined desalting and decoloring technology to prepare the crude lactose liquid into a refined lactose liquid, and then adopts a biological enzymolysis technology to prepare a high-concentration galactose glucose mixture with low lactose and milk mineral salt contents.

More specifically, the invention carries out desalination and decoloration on skim milk ultrafiltration penetrating fluid (crude lactose liquid) through nanofiltration, electrodialysis, ion exchange and activated carbon filtration adsorption, then carries out direct hydrolysis of lactase or immobilized lactase hydrolysis, the lactose hydrolysis rate reaches more than 95 percent, the ash content in the obtained product is less than 0.3 percent of the total dry matter, the total content of galactose, glucose and lactose is more than 99.0 percent, then carries out concentration through an RO membrane and vacuum evaporation (rotary fluidized bed) to prepare galactose glucose mixed solution (the total solid content is more than 55 percent), then carries out pasteurization and enzyme deactivation treatment at 85-95 ℃/15-30s on the mixed solution, and fills the mixed solution into a sterile bag or a sterile barrel by adopting a sterile filling technology to prepare a galactose glucose mixture with high concentration and high purity, the main components of the mixture are galactose and glucose, and minimal amounts of lactose and lactase (or no lactase).

Thus, the present invention provides a method for preparing a galactose glucose mixture, comprising the steps of:

1) taking milk (preferably skimmed milk) as a raw material, and preparing a crude lactose liquid;

2) desalting and decoloring the crude lactose liquid to obtain refined lactose liquid;

3) adding beta-galactosidase into refined lactose liquid to hydrolyze lactose;

4) vacuum concentrating or concentrating with RO membrane to obtain refined and concentrated galactose glucose mixture.

In a specific embodiment of the present invention, in step 1), when the milk is fresh milk, whole milk, half-fat milk, reconstituted milk, nonreactive milk, buffalo milk, the skim milk is obtained by removing impurities by filtration and centrifugal separation, and then pasteurized and ultrafiltered, preferably, the pore size of the ultrafiltration membrane in the ultrafiltration process is 0.01 μm to 0.05 μm.

Wherein the specific operations of filtering, impurity removing and centrifugal separation are that milk is filtered by a 60-80 mesh filter to remove partial impurities or foreign matters, the milk is preheated to 50-60 ℃, and is separated by a centrifuge (the rotating speed is 5000-;

wherein the pasteurization is carried out by pasteurizing (70-90 deg.C for 15s) skimmed milk, and cooling to 8-10 deg.C;

wherein the specific operation of ultrafiltration is that the pasteurized skim milk is ultrafiltered (aperture is 0.01-0.05 μm, membrane pressure range is 2-6bar), the molecular weight cut-off is more than 500u, and crude lactose liquid and protein liquid are separated.

In a specific embodiment of the present invention, the step 2) comprises the following steps:

a. and (4) nanofiltration: preferably, the aperture of the nanofiltration membrane is 0.001-0.002 μm, and the membrane pressure is 10-15 bar; the process can retain molecular weight of 150-;

b. cation exchange: passing lactose solution through cation exchange resin, preferably the pore diameter of the resin is 0.5mm-1.0 mm; the cation exchange resin has weak reactive groups such as carboxyl (-COOH) groups, and can be used for removing second order ions (such as calcium/magnesium ions);

c. electrodialysis: under the action of an external direct current electric field, ion exchange membranes are used for carrying out selective permeation separation on ions in the lactose liquid; the process can be used for ion migration of anions and cations in the solution, and phosphate ions, chloride ions, hydroxide ions, calcium ions, potassium ions, magnesium ions and sodium ions in the lactose solution are removed through anion exchange membranes and cation exchange membranes respectively;

d. anion exchange: passing lactose solution through anion exchange resin, preferably the pore diameter of the anion exchange resin is 0.1-0.5 mm; the anion exchange resin contains weak base groups and can be used for removing phosphate ions, chloride ions and citrate ions;

e. activated carbon adsorption: preferably, activityThe diameter of the micropores on the carbon surface is 2-10 nm, the activated carbon has a huge surface area, and the preferred surface area per gram of the activated carbon is 500-1500 m²(ii) a The process can be used to adsorb beta carotene and vitamins in the lactose liquor.

In a particular embodiment of the invention, the beta-galactosidase is derived from Kluyveromyces lactis (Kluyveromyces lactis).

In a particular embodiment of the invention, the temperature of the hydrolysis is between 35 and 45 ℃.

In a particular embodiment of the invention, the pH of the hydrolysis is in the range of 5.0 to 7.0.

In a specific embodiment of the invention, the vacuum concentration conditions are vacuum degree of-0.7 to-0.8 bar and temperature of 50-70 ℃.

In one embodiment of the present invention, the pore size of the RO membrane is 1.0 to 5.0 nm.

In a specific embodiment of the invention, the step 4) is further followed by a step 5) of sterilizing and enzyme-killing, wherein the refined and concentrated galactose glucose mixed solution is pasteurized and enzyme-killed, preferably at 85-95 ℃ for 15-30 s; more preferably, a drying step is included after step (5) to prepare a galactose glucose mixed powder.

It is another object of the present invention to provide a galactose and glucose mixture, preferably a liquid or powder, prepared by the above method.

Technical effects of the invention

The preparation method of the invention has the following advantages:

1. the invention uses milk as raw material to extract lactose

In the prior art, lactose is generally extracted by using a byproduct lactose liquid of cheese (containing lactalbumin, a leavening agent and rennin) as a raw material, wherein the leavening agent generates protease to decompose protein, the lactose is decomposed to generate lactic acid, and the obtained lactose has many impurities and is not beneficial to subsequent lactose hydrolysis. The invention directly uses milk as raw material to prepare lactose liquid, and the prepared lactose has high purity and stable crystal form, and is beneficial to subsequent enzymolysis.

2. The invention carries out desalination and refining on the lactose liquid before hydrolyzing the lactose liquid

In the prior art, lactase is generally directly added into crude lactose liquid, the obtained galactose glucose mixture contains a large amount of salt ions, and the galactose and the glucose are both monosaccharides, have small molecules and high concentration and viscosity, and the desalination, refining and concentration technology of the mixture has higher difficulty, so that the high-concentration refined galactose glucose mixture is difficult to obtain. Before hydrolysis, the coarse lactose liquid is treated through electrodialysis, ion exchange and active carbon filtration to obtain refined lactose liquid, so that a high-concentration and high-purity galactose glucose mixture is obtained, wherein the lactose hydrolysis rate is over 95 percent, and the ash content is less than 0.3 percent of the total solid matter mass.

In the method for preparing the galactose glucose mixture from the lactose, the hydrolysis rate of the lactose reaches more than 95%, the galactose content in the prepared mixture is more than 22%, the glucose content is more than 22%, the lactose content is less than 5.0%, the dry matter (namely, the total solid matter) of the lactose liquid is more than 55%, the ash content is less than 0.3% of the dry matter, and the pH value is more than 5. The invention solves the problems of low sweetness, high content of milk mineral salt and lactose intolerance existing in the direct application of the crude milk sugar solution. Since the solubility of galactose in water is 68g/100ml (25 ℃) and the solubility of glucose in water is 83g/100ml (20 ℃), the mixture is not easy to crystallize under the normal temperature condition, and can be used as a natural raw material to be applied to various liquid dairy products or other random foods. The quality specification is as follows:

TABLE 1

Item	Index (I)	Inspection method
			Galactose, g/100g ≥	22.0	GB/T 23780
Glucose, g/100g ≥	22.0	GB 5009.8
			Lactose, g/100g is less than or equal to	5.0	GB 5009.8
Dry matter (solid matter), g/100g ≥	55	GB/T 12143
			pH value	5.0～7.0	GB 5009.237
Ash content of less than or equal to g/100g	0.15	GB5009.4-2016

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments.

The methods used in the following examples are conventional methods unless otherwise specified, and the reagents used are commercially available reagents unless otherwise specified.

Example 1

A preparation method of a galactose glucose mixture comprises the following steps:

1) taking whole milk as a raw material, and preparing a crude milk liquid glucose, which comprises the following steps:

a. preparing skim milk: filtering raw milk with a 60-mesh duplex filter, and separating into skimmed milk and cream with skimmed milk fat content of 0.05% and impurity content less than 0.05g/10ml by a centrifugal separator at 5000 rpm.

b. Pasteurization: the skim milk was pasteurized (70 ℃/15 s).

c. And (3) ultrafiltration: separating skim milk with ultrafiltration membrane into crude lactose liquid and milk protein liquid, at 6-10 deg.C, membrane pressure of 6bar, pore diameter of 0.01 μm, and lactose liquid solid content of 5.0%.

2) Desalting and decoloring the crude lactose liquid to obtain a refined lactose liquid, which comprises the following steps:

a. and (4) nanofiltration: the lactose liquid is nano-filtered, the aperture is 0.001 mu m, the temperature is 8 ℃, the membrane pressure is 10bar, the sodium ion is reduced to 600mg/kg from the original 1000mg/kg, the potassium ion is reduced to 2200mg/kg from the original 3200mg/kg, and the lactose content is concentrated to 12.0 percent from the original 4.0 percent.

b. Cation exchange: the lactose liquid is treated by weak acid cation exchange resin, the aperture is 0.5mm, and calcium ions are reduced to 200mg/kg from 800mg/kg and magnesium ions are reduced to 80mg/kg from 180mg/kg by ion exchange technology.

c. Electrodialysis: under the action of an external direct current electric field, cation and anion in the solution are selectively permeated through electrodialysis (polyethylene heterogeneous ion exchange membrane), sodium ions are reduced to 200mg/kg from the original 600mg/kg, potassium ions are reduced to 1000mg/kg from the original 2000mg/kg, calcium ions are reduced to 30mg/kg from 200mg/kg, magnesium ions are reduced to 20mg/kg from the original 50mg/kg, phosphate ions are reduced to 80mg/kg from the original 900mg/kg, chloride ions are reduced to 5mg/kg from the original 10mg/kg, and hydroxide ions are reduced to 2mg/kg from the original 5 mg/kg.

d. Anion exchange: the lactose liquid is processed by weak base anion exchange resin with aperture of 0.1mm, the resin contains weak base group, phosphate radical ion is reduced to 5mg/kg from original 80mg/kg, chloride ion is reduced to 1.0mg/kg from original 5.0mg/kg, and hydroxyl ion is reduced to 1mg/kg from original 2 mg/kg.

e. Activated carbon adsorption: the diameter of the micropores on the surface of the activated carbon is 2nm, and the surface area of each gram of the activated carbon is 1500m²Beta carotene in the adsorbed lactose liquid is reduced to be not detected from 0.5 mu g/100g, and vitamin B2 is reduced to be not detected from 0.6mg/100 g.

3) Adding beta-galactosidase into refined lactose liquid to hydrolyze lactose, which comprises the following steps:

adding 0.2% beta-galactosidase (with the enzyme activity of 30 ten thousand) generated by kluyveromyces lactis into the 15% concentrated lactose liquid obtained in the step 2), hydrolyzing at the temperature of 45 ℃ and the pH value of 5.5 for 4 hours, and hydrolyzing lactose into 6.0g of galactose and 6.0g of glucose, wherein the hydrolysis rate reaches more than 95%.

4) Carrying out vacuum concentration or RO membrane concentration on the hydrolysate to obtain refined and concentrated galactose glucose mixed solution, wherein the specific operation comprises the following steps:

concentrating galactose glucose mixed solution to 56.0% by single effect or multiple effect vacuum evaporator solid with vacuum degree of-0.7 bar and temperature of 50 deg.C. Or concentrating with RO membrane with pore diameter of 1.0nm to 56.0% of galactose glucose mixed solution solid.

5) Sterilization and enzyme inactivation: pasteurizing and inactivating enzyme of the galactose glucose mixed solution at 85 ℃/15 s.

6) Sterile perfusion: perfusion was performed under sterile or ultra-clean conditions at 25 ℃.

The quality standard test results of the finished products are shown in the table

TABLE 2

Example 2

A preparation method of a galactose glucose mixture comprises the following steps:

1) the method for preparing the coarse milk sugar liquid by taking fresh milk as a raw material comprises the following steps:

a. preparing skim milk: filtering raw milk with 70 mesh filter, centrifuging at 5500rpm to obtain skimmed milk with fat content of 0.05% and dilute cream, and removing impurities less than 0.03g/10 ml.

b. Pasteurization: the skim milk was pasteurized (80 ℃/15 s).

c. And (3) ultrafiltration: separating skim milk with ultrafiltration membrane into crude lactose liquid and milk protein liquid, with aperture of 0.03 μm, separation temperature of 10-12 deg.C, membrane pressure of 4bar, and lactose liquid solid content of 15.0%.

2) Desalting and decoloring the crude lactose liquid to obtain a refined lactose liquid, which comprises the following steps:

a. and (4) nanofiltration: the nanofiltration temperature is 8-10 ℃, the membrane pressure is 12bar, the pore diameter is 0.0015 mu m, the sodium ion content is reduced to 500mg/kg from the original 900mg/kg, the potassium ion content is reduced to 1800mg/kg from the original 3000mg/kg, and the lactose content is concentrated to 14.5% from the original 5.0%.

b. Cation exchange: the lactose liquid is treated by weak acid cation exchange resin, the aperture is 0.85mm, and calcium ions are reduced to 150mg/kg from 600mg/kg and magnesium ions are reduced to 50mg/kg from 150mg/kg by ion exchange technology.

c. Electrodialysis: electrodialysis (polyethylene heterogeneous ion exchange membrane) selectively permeates cations and anions in the solution, wherein sodium ions are reduced to 100mg/kg from original 500mg/kg, potassium ions are reduced to 600mg/kg from original 1800mg/kg, calcium ions are reduced to 10mg/kg from 150mg/kg, magnesium ions are reduced to 10mg/kg from original 50mg/kg, phosphate ions are reduced to 60mg/kg from original 700mg/kg, chloride ions are reduced to 3mg/kg from original 15mg/kg, and hydroxide ions are reduced to 1mg/kg from original 3 mg/kg.

d. Anion exchange: the lactose liquid is processed by weak base anion exchange resin with aperture of 0.3mm, the resin contains weak base group, phosphate radical ion is reduced to 2mg/kg from original 60mg/kg, chloride ion is reduced to 1.0mg/kg from original 5.0mg/kg, and hydroxyl ion is reduced to 0.5mg/kg from original 1 mg/kg.

e. Activated carbon adsorption: the diameter of the micropores on the surface of the activated carbon is 6nm, and the surface area of each gram of the activated carbon is 1000m²Beta carotene in the adsorbed lactose liquid is reduced to be not detected from 0.5 mu g/100g, and vitamin B2 is reduced to be not detected from 0.6mg/100 g.

3) Adding beta-galactosidase into refined lactose liquid to hydrolyze lactose, which comprises the following steps:

adding 0.15% beta-galactosidase (with the enzyme activity of 30 ten thousand) generated by kluyveromyces lactis into the 14.5% concentrated lactose liquid obtained in the step 2), hydrolyzing at 40 ℃ and pH value of 6.0 for 6 hours, and hydrolyzing lactose into 5.8g of galactose and 5.8g of glucose, wherein the hydrolysis rate is over 95%.

4) Carrying out vacuum concentration or RO membrane concentration on the hydrolysate to obtain refined and concentrated galactose glucose mixed liquor, which specifically comprises the following steps:

concentrating galactose glucose mixed solution to 58.0% by single-effect or multi-effect vacuum evaporator with vacuum degree of-0.75 bar and temperature of 60 deg.C or RO membrane concentration with aperture of 3 nm.

5) Sterilization and enzyme inactivation: pasteurizing and inactivating enzyme of the galactose glucose mixed solution at the temperature of 90 ℃/30s, and then drying to obtain galactose glucose mixed powder.

6) Sterile perfusion: perfusion was performed under sterile or ultra-clean conditions at 30 ℃.

The detection results of the quality standard of the finished product are as follows:

TABLE 3

Item	Index (I)	Inspection method
			Galactose, g/100g	25.0	GB/T 23780
Glucose, g/100g	25.0	GB 5009.8
			Lactose, g/100g	1.5	GB 5009.8
Dry matter (solids), g/100g	58.0	GB/T 12143
			pH value	6.0	GB 5009.237
Ash content, g/100g	0.12	GB5009.4-2016

Example 3

A preparation method of a galactose glucose mixture comprises the following steps:

1) the method for preparing the crude milk sugar liquid by taking the skim milk as a raw material comprises the following steps:

a. pasteurization: the skim milk was pasteurized (90 ℃/15 s).

b. And (3) ultrafiltration: separating skim milk with ultrafiltration membrane into crude lactose liquid and milk protein liquid, with pore diameter of 0.05 μm, membrane pressure of 4bar, separation temperature of 9-10 deg.C, and lactose liquid solid content of 5.8%.

2) Desalting and decoloring the crude lactose liquid to obtain refined lactose liquid, which comprises the following steps:

a. and (4) nanofiltration: the crude lactose liquid is subjected to nanofiltration, the nanofiltration temperature is 9-12 ℃, the membrane pressure is 15bar, the pore diameter is 0.002 mu m, the sodium ions are reduced to 500mg/kg from the original 900mg/kg, the potassium ions are reduced to 1800mg/kg from the original 3000mg/kg, and the lactose content is concentrated to 14.8% from the original 5.8%.

b. Cation exchange: the lactose liquid is treated by weak acid cation exchange resin, the aperture is 1.0mm, and calcium ions are reduced to 150mg/kg from 600mg/kg and magnesium ions are reduced to 50mg/kg from 150mg/kg by ion exchange technology.

c. Electrodialysis: the lactose solution is subjected to selective permeation of cations and anions in the solution through electrodialysis (polyethylene heterogeneous ion exchange membrane), wherein sodium ions are reduced to 100mg/kg from original 500mg/kg, potassium ions are reduced to 600mg/kg from original 1800mg/kg, calcium ions are reduced to 5mg/kg from 150mg/kg, magnesium ions are reduced to 5mg/kg from original 50mg/kg, phosphate ions are reduced to 6mg/kg from original 700mg/kg, chloride ions are reduced to 2mg/kg from original 15mg/kg, and hydroxide ions are reduced to 1mg/kg from original 6 mg/kg.

d. Anion exchange: the lactose liquid is processed by weak base anion exchange resin with aperture of 0.5mm, the resin contains weak base group, phosphate radical ion is reduced to 1mg/kg from original 6mg/kg, chloride ion is reduced to 0.5mg/kg from original 2.0mg/kg, and hydroxyl ion is reduced to 0.1mg/kg from original 1 mg/kg.

e. Activated carbon adsorption: the diameter of micropores on the surface of the activated carbon is 10nm, and the surface area of each gram of the activated carbon is 500m²Beta carotene in the adsorbed lactose liquid is reduced to be not detected from 0.5 mu g/100g, and vitamin B2 is reduced to be not detected from 0.6mg/100 g.

3) Adding beta-galactosidase into refined lactose liquid to hydrolyze lactose, which comprises the following steps:

adding 0.2% beta-galactosidase (with the enzyme activity of 30 ten thousand) generated by kluyveromyces lactis into the 14.8% concentrated lactose liquid obtained in the step 2), hydrolyzing at 35 ℃ and pH value of 5.8 for 8 hours, and hydrolyzing lactose into 6.0g of galactose and 6.0g of glucose, wherein the hydrolysis rate is over 95%.

4) Carrying out vacuum concentration or RO membrane concentration on the hydrolysate to obtain refined and concentrated galactose glucose mixed liquor, which specifically comprises the following steps:

concentrating galactose glucose mixed solution to 60% solid by single-effect or multi-effect vacuum evaporator with vacuum degree of-0.8 bar and temperature of 70 deg.C or RO membrane concentration with aperture of 5 nm.

5) Sterilization and enzyme inactivation: pasteurizing and inactivating enzyme of the galactose glucose mixed solution at 95 ℃/30 s.

6) Sterile perfusion: perfusion was performed under sterile or ultra-clean conditions at 28 ℃.

The quality standard test results of the finished products are shown in the table

TABLE 4

Item	Index (I)	Inspection method
			Galactose, g/100g	27.0	GB/T 23780
Glucose, g/100g	27.0	GB 5009.8
			Lactose, g/100g	1.0	GB 5009.8
Dry matter (solids), g/100g	60	GB/T 12143
			pH value	5.8	GB 5009.237
Ash content, g/100g	0.15	GB5009.4-2016

Example 4

The same procedure as in example 3 above, except that the lactose hydrolysis in step 3) has a pH of 5.0. The detection results of the quality standard of the finished product are as follows:

TABLE 5

Example 5

The same procedure as in example 3 above, except that the lactose hydrolysis in step 3) had a pH of 7.0. The detection results of the quality standard of the finished product are as follows:

TABLE 6

Item	Index (I)	Inspection method
			Galactose, g/100g	23.6	GB/T 23780
Glucose, g/100g	24.5	GB 5009.8
			Lactose, g/100g	0.86	GB 5009.8
Dry matter (solids), g/100g	56	GB/T 12143
			pH value	7.0	GB 5009.237
Ash content, g/100g	0.14	GB5009.4-2016

Comparative example 1

The method is the same as the step of the embodiment 2, and is characterized in that the whey liquid by-product of cheese in the step 1) is taken as a raw material to be subjected to ultrafiltration separation, desalting refining, enzymolysis and concentration treatment, and the specific parameters are the same as those of the ultrafiltration in the step 1) and the steps 2) -6) of the embodiment 2).

The quality standard detection results of the obtained finished products are as follows:

TABLE 7

Item	Index (I)	Inspection method
			Galactose, g/100g	17.6	GB/T 23780
Glucose, g/100g	16.8	GB 5009.8
			Lactose, g/100g	15.0	GB 5009.8
Dry matter (solids), g/100g	56	GB/T 12143
			pH value	4.5	GB 5009.237
Ash content, g/100g	1.56	GB5009.4-2016

Comparative example 2

The same procedure as in example 2 above, except that the order of lactose hydrolysis in step 3) was changed, i.e. lactose hydrolysis was first performed after completion of step 1) ultrafiltration, and then step 2) and steps 4) to 6) were performed in sequence.

The quality standard detection results of the obtained finished products are as follows:

TABLE 8

Item	Index (I)	Inspection method
			Galactose, g/100g	12	GB/T 23780
Glucose, g/100g	12.6	GB 5009.8
			Lactose, g/100g	25	GB 5009.8
Dry matter (solids), g/100g	56	GB/T 12143
			pH value	4.8	GB 5009.237
Ash content, g/100g	2.5	GB5009.4-2016

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.