A method for photocatalytically removing lactose from milk products

Abstract

The present invention belongs to the field of industrial catalysis technology, and specifically relates to a photocatalytic composite material and a method for removing lactose from milk products. First, a photocatalytic material is prepared, and nano-TiO2 and food-grade activated carbon (AC for short) are directly ground, or TiCl4, ethylene glycol, and food-grade activated carbon are used to synthesize TiO2 / activated carbon composite materials by hydrothermal method, and the composite materials are applied to food-grade pollution-free conductive substrates such as titanium plates or graphite plates, and the coated substrates and titanium plates of the same area are loaded into a reactor, and liquid milk to be treated is put in, and strong sunlight or weak ultraviolet light is applied under stirring conditions, and low voltage is applied to the two plates at the same time. Under this condition, lactose and glucose in the liquid milk are reacted to generate sugars such as erythrose that can be absorbed by the human body. This method does not change the flavor of milk products, retains the nutritional components of milk products, has a simple process, and has good application prospects and economic value.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial catalysis, and in particular relates to a photocatalytic composite material and a method for removing lactose from milk products. Background Art

[0002] Animal milk products such as milk, goat milk and camel milk and dairy products are rich in nutrients. Taking milk as an example, every 100 grams of milk contains approximately 54 kcal of energy, 3 grams of protein, 3.2 grams of fat, 3.4 grams of carbohydrates, 15 mg of cholesterol, 24 micrograms of vitamin A, 0.03 mg of thiamine, 0.14 mg of riboflavin, 0.1 mg of niacin, 1 mg of vitamin C, 0.21 mg of vitamin E, 104 mg of calcium, 73 mg of phosphorus, 109 mg of potassium, 37.2 mg of sodium, 11 mg of magnesium, 0.3 mg of iron, 0.42 mg of zinc, 1.94 micrograms of selenium, 0.02 mg of copper, and 0.03 mg of manganese. Although dairy products are rich in nutrients, a large number of people have adverse reactions to the lactose in dairy products, which is called lactose intolerance, also known as lactose indigestion or lactose malabsorption. The main reason is that the human body does not produce lactase to break down lactose. The lactose in dairy products cannot be digested and absorbed. The lactose will be broken down by bacteria in the intestines and turned into lactic acid, thereby destroying the alkaline environment of the intestines, causing the intestines to secrete a large amount of alkaline digestive fluid to neutralize the lactic acid, which can easily cause mild diarrhea.

[0003] Lactose is a carbohydrate found in human and mammalian milk. It is a disaccharide composed of glucose and galactose with a molecular formula of C 12 H 22 O 11 In nature, lactose only exists in the milk of mammals. The lactose content in cow's milk is generally 4.5-5.0%. Lactose is a disaccharide formed by the combination of D-glucose and D-galactose with a β-1,4 bond, also known as 1,4-galactoside glucose, which is a reducing sugar. Lactose has two isomers: α-lactose and β-lactose. α-lactose can easily combine with a molecule of crystal water to become α-lactose hydrate (α-Lactose Monohydrate), so there are actually three configurations of lactose. That is, α-lactose hydrate, α-lactose anhydrous and β-lactose.

[0004] Lactose intolerance has not yet been treated with good medical treatment methods such as drugs. Currently, dietary adjustment has become the best way to solve the problem of lactose intolerance. Lactose hydrolyzed milk with a hydrolysis degree of 70%-90%, also known as low-lactose milk, is a choice that can ensure the nutritional value of milk and can be used by lactose intolerant people. The main physical and chemical indicators of low-lactose milk currently sold on the market are: milk fat ≥3.1%, protein ≥2.9%, non-fat milk solids>8.1%, hydrolysis rate ≥70%, specific gravity ≥1.028, lactose ≤1.2%, acidity ≤18°T, which means that the problem of lactose removal still exists. Many companies cannot solve the problem of removing lactose from milk products due to technical reasons, so low-lactose milk on the market has just started. According to the mechanism of lactose hydrolysis in milk, there are four production methods for low-lactose milk: physical removal, chemical acid hydrolysis, enzyme hydrolysis and genetic engineering technology. The physical method mainly removes most of the lactose by filtering, and uses multi-stage membrane separation and centrifugation to remove lactose, so that the total sugar level is below 0.5%, and the product basically retains the original nutritional essence and taste of milk. However, the physical method removes the vitamins and minerals that are very important to the human body along with lactose. If they are added later, the production cost will be greatly increased, and the nutrients will be wasted; the acid hydrolysis method uses strong acid and high temperature to hydrolyze lactose (pH1-3, temperature 100-150℃). This method is very easy to cause the raw milk to deteriorate and cannot be used at present; the enzyme hydrolysis method is to hydrolyze lactose into monosaccharides that are easily absorbed and utilized by the human body by adding exogenous β-galactosidase. This method has mild hydrolysis conditions, simple products, good taste, and will not destroy other nutrients in milk. It is the safest and most effective method for producing low-lactose milk to date. However, exogenous proteins will be mixed into milk, and the production cost is high. The enzyme is easily contaminated by microorganisms when acting, and the action time is difficult to control. At the same time, since lactose is hydrolyzed into monosaccharides, its sweetness will increase by 3-4 times. In addition, the Maillard reaction is prone to occur during sterilization, resulting in browning, which affects the sensory quality of the product. The industrial production of low-lactose milk by enzyme hydrolysis requires high investment and high technical difficulty. The last and more direct method is to ferment raw milk into yogurt for consumption. Lactose is decomposed into a molecule of galactose and glucose, which can be directly absorbed and utilized.

[0005] Existing invention patents show that there is little research on the removal of lactose. For example, the disclosed invention patents (CN202011396680.5, CN202011396984.1, CN202011396982.2) proposed a method for synthesizing derivatives of galactose and lactose, but did not mention the removal of lactose. The disclosed Chinese invention patent (CN202011396680.5) proposed a method for synthesizing galactose derivatives and their application in the preparation of oligosaccharides. The disclosed invention patent (CN202210558827.9) proposed a processing equipment for lactose-free dairy products involving dairy products, but did not make innovations and breakthroughs in the lactose removal process. The authorized Chinese invention patent "Method for removing lactose from a solution" (CN201580006107.X) provides protein-functionalized magnetic nanoparticles, which contain magnetic nanoparticles (MNPs) to which proteins or enzymes that bind lactose have been fixed. The protein-functionalized magnetic nanoparticles are particularly suitable for separating lactose from solutions containing lactose, such as milk, cheese, yogurt, flavored milk, etc. The protein-functionalized MNPs can be added to a solution containing lactose and bind to the lactose in the solution. Then, the MNPs bound to lactose can be magnetically removed from the solution, for example, by applying an external magnetic field. The MNPs in this method need to be protected, and two methods are used: the first method is to coat the MNPs with an organic shell, such as a surfactant, a polymer, and a biomolecule. Another method is to coat the MNPs with an inorganic layer, such as silica and a metal, and finally to combine with lactase to obtain a low-lactose product. The separation problem of the magnetic nanoparticles is not detailed, and the overall industrialization is difficult. The patent also expires in 2021. The authorized Chinese invention patent "A method for preparing low-lactose milk" (CN200710000802.2) provides a method for preparing low-lactose milk. The method includes steps of purification, sterilization, cooling, preparing composition (stabilizer), adding lactase and filling, etc., and adopts enzymatic hydrolysis method. The method has good effect overall. Although lactose cannot be completely removed and the protein content is slightly reduced, dietary fiber is also added to the formula to basically maintain the flavor of the milk. The above method can be said to prepare low-lactose milk, which cannot completely remove lactose and will reduce the quality of the milk. At the same time, lactose is not converted into usable high-value and high-nutrition ingredients for human absorption.

[0006] The present invention proposes a method for preparing low-lactose milk products using the principle of photocatalysis. First, a photocatalytic material is prepared, and nano-TiO 2 and food grade activated carbon (AC), or use TiCl 4 , ethylene glycol, and food-grade activated carbon hydrothermal synthesis of TiO 2 / activated carbon composite material, which is applied to food-grade pollution-free conductive substrates such as titanium plates or graphite plates, the coated substrate and a titanium plate of the same area are loaded into a reactor, and liquid milk to be treated is put into the reactor. Under stirring conditions, strong sunlight or weak ultraviolet light is applied, and a low voltage is applied to the two plates at the same time. Under this condition, the lactose and glucose in the liquid milk are reacted to produce sugars such as erythrose that can be absorbed by the human body. Summary of the invention

[0007] The purpose of the present invention is to provide a process for removing lactose from liquid milk, which utilizes a photocatalytic method under an external electric field to achieve the effect of removing lactose from milk products.

[0008] To achieve the above purpose, the process steps are as follows:

[0009] (1) Direct use of nano-TiO 2 Mix and grind with food-grade activated carbon, or synthesize TiO by hydrothermal method 2 / AC composite materials;

[0010] (2) The TiO prepared in step (1) 2 / AC composite material, and polyvinylidene fluoride are prepared into a paste in an ethanol solution according to a certain mass ratio, and evenly bonded on a conductive substrate, dried and used, which is called electric plate A; at the same time, a titanium conductive plate of the same size is prepared, which is called electric plate B;

[0011] (3) In an electrolytic cell equipped with cooling, stirring and light source, plate A and plate B are placed, with the coated surface of plate A facing plate B; non-delactose liquid milk A is added and immersed in the plates, stirring is started, and cooling and light control switches are turned on at the same time, and relative voltages or currents are applied to the two plates. After a certain reaction time, liquid milk B is obtained for use;

[0012] (4) The liquid milk B described in step (3) is filtered and impurities are removed under certain temperature conditions, and then sterilized to obtain liquid milk C.

[0013] Liquid milk C is aseptically filled, stored or used for the next step of milk powder preparation as required. The milk product can also be used as raw milk for yogurt.

[0014] Preferably, the TiO 2 / AC composite materials can be made of nano-TiO 2 and food-grade activated carbon, directly under clean and pollution-free grinding conditions, wet ball milling or dry ball milling, drying after ball milling, and then sieving to obtain TiO 2 / AC composite material.

[0015] Preferably, the TiO 2 / AC composite materials can be prepared by hydrothermal method. The preparation steps are as follows: ① Take titanium tetrachloride, ethylene glycol, and a specific surface area greater than 1000 m 2 / g of food-grade activated carbon (AC for short), deionized water, the non-delactose liquid milk is called liquid milk A, and the above are reserved; ② put ethylene glycol into a stirred reactor with atmosphere protection, start stirring, and drop titanium tetrachloride under inert atmosphere protection, and continue stirring until the solution is uniform; ③ transfer the solution to a corrosion-resistant hydrothermal kettle with inert atmosphere protection, put in activated carbon and deionized water, seal and replace with inert atmosphere; ④ react the reactor in step ③ at a reaction temperature of 100-200°C and a reaction time of 2-30 hours, and then cool to room temperature; ⑤ filter the product in step ④, wash with distilled water until the pH value of the washing liquid is neutral, and vacuum dry the filtered solid at 40-100°C for 6-12 hours, and then sieve with 100 mesh. The sieved material is TiO 2 / AC composite material.

[0016] Further preferably, in the hydrothermal method for preparing TiO 2 / AC composite material steps: the titanium tetrachloride in step ① is of analytical grade or above; the volume ratio of titanium tetrachloride, ethylene glycol and deionized water in step ① is 1:20~40:50~70, and each 1mL of titanium tetrachloride corresponds to about 1g of food-grade activated carbon; the inert atmosphere in steps ② and ③ is nitrogen or argon.

[0017] Preferably, the polyvinylidene fluoride in step (2) is an analytically pure product or higher without color additives; the TiO 2 The mass ratio of the / AC composite material to the polyvinylidene fluoride is 10:1-5:1.

[0018] Preferably, the conductive substrate in step (2) is made of any one of titanium, silver, copper, graphite, or an alloy of titanium, silver, and copper, but does not contain heavy metals such as chromium and mercury that are harmful to the human body.

[0019] Preferably, in step (3), the area of ​​a single electrode corresponding to every 50 mL of liquid milk is greater than 3 square centimeters; the reaction temperature is controlled to be no greater than 20° C., and the liquid stirring state is ensured to be good; and the required light source is visible light and ultraviolet light with adjustable power and wavelength range.

[0020] Preferably, the relative potential difference between the electrode A and the electrode B in step (3) is 0-2 V, the current intensity is 0-100 A, and the reaction time is 0.5-10 hours.

[0021] Preferably, the temperature required in step (4) is less than 20° C., and the fluidity of the liquid is ensured, and the filtration is mechanical filtration or membrane filtration.

[0022] The sterilization method in step (4) is pasteurization or ultra-high temperature instant sterilization, which is a conventional sterilization method for liquid milk. There are two basic pasteurization processes. The first is to heat the liquid milk to 62℃-65℃ and keep it for 30 minutes; the second method is to heat the milk to 75℃-90℃ and keep it warm for 15s-16s; the ultra-high temperature instant sterilization method is a temperature above 135℃, and the heating time is not less than 2 seconds.

[0023] All of the above-mentioned process must be carried out under aseptic conditions to ensure safe food production, thus ensuring the safety of milk products from secondary contamination.

[0024] This method converts glucose and lactose in milk into sugars such as erythrose with high nutritional value during the milk processing process, does not change the flavor of the milk, retains the nutritional components of the milk, has a simple process, and has good application prospects and economic value. DETAILED DESCRIPTION

[0025] Example 1

[0026] (1) Take 1 mL of titanium tetrachloride and 25 mL of ethylene glycol with a specific surface area of ​​1500 m 2 / g food-grade activated carbon (AC) 1g (300 mesh), deionized water 50mL, non-delactose liquid milk is called liquid milk A, and the lactose content of 50mL is 4.8% (mass ratio), which is set aside.

[0027] (2) Add ethylene glycol to a stirring vessel with N 2 In the reactor protected by atmosphere, start stirring. Add titanium tetrachloride dropwise. Floccules may appear during the reaction. Stir continuously until the solution is uniform.

[0028] (3) Transfer the homogeneous solution to a 100 mL hydrothermal reactor with atmosphere protection, introduce 50 mL of prepared deionized water, stir lightly with a stirring rod, add 1 g of prepared activated carbon, seal the reactor, and heat with N 2 Replace the gas in the kettle.

[0029] (4) Heat the hydrothermal autoclave to 150°C and react at this temperature for 10 hours. Cool down and filter, wash the filter cake with deionized water until the washing liquid is neutral, and ensure that the washing is performed at least three times.

[0030] (5) The filter cake was sent to a vacuum drying oven and dried at 60°C for 8 hours. Then it was sieved with 100 mesh to obtain the sieved fine powder, which is TiO 2 / AC composite material.

[0031] (6) TiO 2The AC composite material and polyvinylidene fluoride were dissolved in 5 mL of ethanol at a mass ratio of 9:1, and the temperature was controlled at 70°C until the polyvinylidene fluoride was completely dissolved and evaporated with the ethanol, and a viscous paste was formed under continuous stirring. The above paste was applied to a 4 square centimeter platinum sheet and dried at room temperature, which was called electrode A. A platinum sheet of the same area was prepared, which was called electrode B.

[0032] (7) Transfer the plate to an electrolytic cell with cooling, stirring, and ultraviolet light (fluorescent light), and install plate A and plate B, with the coated surface of plate A facing plate B. Add the prepared liquid milk A, making sure that the plate is submerged, start stirring, turn on the cooling control switch to control the reaction temperature not to exceed 20°C, turn on the light and control the intensity, using ultraviolet light with a wavelength of 360nm and a power of 30kW / h, applying a potential of 0.5V to plate A and a voltage of 0V to plate B. React under this condition for 2 hours, stop powering, lighting, stirring and cooling, and obtain liquid milk B for use. At this time, the lactose content of liquid milk B is tested, and the lactose content has dropped to 0.53% (mass ratio), and the lactose removal rate reaches 89%.

[0033] (8) Filter the liquid milk B to remove mechanical impurities and control the temperature to no higher than 20°C; then transfer to the pasteurization stage and keep it at 65°C for 30 minutes. Then cool the liquid milk to 20°C and fill it or store it according to production needs.

[0034] Example 2

[0035] (1) Take 1 mL of titanium tetrachloride and 30 mL of ethylene glycol with a specific surface area of ​​1500 m 2 / g food-grade activated carbon (AC) 1g (300 mesh), deionized water 50mL, non-delactose liquid milk is called liquid milk A, and the lactose content of 50mL is 4.8% (mass ratio), which is set aside.

[0036] (2) Add ethylene glycol to a stirring vessel with N 2 In the reactor protected by atmosphere, start stirring. Add titanium tetrachloride dropwise. Floccules may appear during the reaction. Stir continuously until the solution is uniform.

[0037] (3) Transfer the homogeneous solution to a 100 mL hydrothermal reactor with atmosphere protection, introduce 50 mL of prepared deionized water, stir lightly with a stirring rod, add 1 g of prepared activated carbon, seal the reactor, and heat with N 2 Replace the gas in the kettle.

[0038] (4) Heat the hydrothermal autoclave to 160°C and react at this temperature for 14 hours. Cool down and filter, wash the filter cake with deionized water until the washing liquid is neutral, and ensure that the washing is performed at least three times.

[0039] (5) The filter cake was sent to a vacuum drying oven and dried at 60°C for 8 hours. Then it was sieved with 100 mesh to obtain the sieved fine powder, which is TiO 2 / AC composite material.

[0040] (6) TiO 2 The AC composite material and polyvinylidene fluoride were dissolved in 5 mL of ethanol at a mass ratio of 9:1, and the temperature was controlled at 70°C until the polyvinylidene fluoride was completely dissolved and evaporated with the ethanol, and a viscous paste was formed under continuous stirring. The above paste was applied to a 4 square centimeter silver sheet and dried at room temperature, which was called electrode A. A platinum sheet of the same area was prepared, which was called electrode B.

[0041] (7) Transfer the plate to an electrolytic cell with cooling, stirring, and ultraviolet light (fluorescent light), and install plate A and plate B, with the coated surface of plate A facing plate B. Add the prepared liquid milk A to ensure that the plate is submerged, start stirring, turn on the cooling control switch to control the reaction temperature not to exceed 20°C, turn on the light and control the intensity, use ultraviolet light with a wavelength of 300nm and a power of 60kW / h, apply a potential of 0.3V to plate A, and apply a voltage of 0 V to plate B. React under this condition for 0.5 hour, stop powering, lighting, stirring and cooling, and obtain liquid milk B for use. At this time, the lactose content of liquid milk B is tested, and the lactose content has dropped to 0.63% (mass ratio), and the lactose removal rate reaches 86.9%.

[0042] (8) Filter the liquid milk B to remove mechanical impurities and control the temperature to no higher than 20°C; then transfer to the pasteurization stage and keep it at 80°C for 15 seconds. Then cool the liquid milk to 20°C and fill it or store it according to production needs.

[0043] Example 3

[0044] (1) Take 1 mL of titanium tetrachloride and 25 mL of ethylene glycol with a specific surface area of ​​1500 m 2 / g food-grade activated carbon (AC) 1g (300 mesh), deionized water 50mL, non-delactose liquid milk is called liquid milk A, and the lactose content of 50mL is 4.8% (mass ratio), which is set aside.

[0045] (2) Add ethylene glycol to a stirring vessel with N 2 In the reactor protected by atmosphere, start stirring. Add titanium tetrachloride dropwise. Floccules may appear during the reaction. Stir continuously until the solution is uniform.

[0046] (3) Transfer the homogeneous solution to a 100 mL hydrothermal reactor with atmosphere protection, introduce 50 mL of prepared deionized water, stir lightly with a stirring rod, add 1 g of prepared activated carbon, seal the reactor, and heat with N 2 Replace the gas in the kettle.

[0047] (4) Heat the hydrothermal autoclave to 150°C and react at this temperature for 10 hours. Cool down and filter, wash the filter cake with deionized water until the washing liquid is neutral, and ensure that the washing is performed at least three times.

[0048] (5) The filter cake was sent to a vacuum drying oven and dried at 60°C for 8 hours. Then it was sieved with 100 mesh to obtain the sieved fine powder, which is TiO 2 / AC composite material.

[0049] (6) TiO 2 The AC composite material and polyvinylidene fluoride were dissolved in 5 mL of ethanol at a mass ratio of 9:1, and the temperature was controlled at 70°C until the polyvinylidene fluoride was completely dissolved and evaporated with the ethanol, and a viscous paste was formed under continuous stirring. The above paste was applied to a 4 square centimeter platinum sheet and dried at room temperature, which was called electrode A. A platinum sheet of the same area was prepared, which was called electrode B.

[0050] (7) Transfer the plate to an electrolytic cell with cooling, stirring, and ultraviolet light (fluorescent lamp), and install plate A and plate B, with the coated surface of plate A facing plate B. Add the prepared liquid milk A to ensure that the plate is immersed, start stirring, turn on the cooling control switch to control the reaction temperature not to exceed 20°C, turn on the light and control the intensity, using visible light with a wavelength of 470nm and a power of 30kW / h, applying a potential of 0.5V to plate A and a voltage of 0V to plate B. React under this condition for 5 hours, stop powering, lighting, stirring and cooling, and obtain liquid milk B for use. At this time, the lactose content of liquid milk B is tested, and the lactose content has dropped to 0.79% (mass ratio), and the lactose removal rate reaches 83.5%.

[0051] (8) Filter the liquid milk B to remove mechanical impurities and control the temperature to no higher than 20°C; then transfer to the pasteurization stage and keep it at 65°C for 30 minutes. Then cool the liquid milk to 20°C and fill it or store it according to production needs.

[0052] Example 4

[0053] (1) Take nano-TiO 2 0.75 g, surface area 1500 m 2 / g of food-grade activated carbon (AC) 1g (300 mesh), the non-delactose liquid milk is called liquid milk A, and the lactose content of 50mL is 4.8% (mass ratio), which is set aside.

[0054] (2) The above TiO 2Mix with activated carbon and ball mill. After ball milling for 6 hours, wash with deionized water ultrasonically, filter, and send the filter cake to a vacuum drying oven to dry at 60°C for 8 hours. Then sieve through 100 mesh to obtain the sieved fine powder, which is TiO 2 / AC composite material.

[0055] (3) TiO 2 The AC composite material and polyvinylidene fluoride were dissolved in 5 mL of ethanol at a mass ratio of 9:1, and the temperature was controlled at 70°C until the polyvinylidene fluoride was completely dissolved and evaporated with the ethanol, and a viscous paste was formed under continuous stirring. The above paste was applied to a 4 square centimeter silver sheet and dried at room temperature, which was called electrode A. A platinum sheet of the same area was prepared, which was called electrode B.

[0056] (4) Transfer the plate to an electrolytic cell with cooling, stirring, and ultraviolet light (fluorescent light), and install plate A and plate B, with the coated surface of plate A facing plate B. Add the prepared liquid milk A, making sure that the plate is submerged, start stirring, turn on the cooling control switch to control the reaction temperature not to exceed 20°C, turn on the light and control the intensity, using ultraviolet light with a wavelength of 300nm and a power of 60kW / h, applying a potential of 0.3V to plate A and a voltage of 0V to plate B. React under this condition for 0.5 hours, stop powering, lighting, stirring and cooling, and obtain liquid milk B for use. At this time, the lactose content of liquid milk B is tested, and the lactose content has dropped to 1.09% (mass ratio), and the lactose removal rate reaches 77.3%.

[0057] (5) Filter the liquid milk B to remove mechanical impurities and control the temperature to no higher than 20°C; then transfer to the pasteurization stage and keep it at 80°C for 15 seconds. Then cool the liquid milk to 20°C and fill it or store it according to production needs.

Claims

1. A method for photocatalytically removing lactose from liquid milk, characterized in that Here are the steps: (1) Directly mix and grind nano-TiO2 and food-grade activated carbon, or prepare TiO2 / AC composite materials by hydrothermal synthesis; (2) The TiO2 / AC composite material prepared in step (1) is mixed with polyvinylidene fluoride in an ethanol solution at a certain mass ratio to form a paste, and the paste is evenly bonded to a conductive substrate, and dried for later use, which is referred to as electrode A. At the same time, a titanium conductive plate of the same size is prepared, which is referred to as electrode B. (3) In an electrolytic cell with cooling, stirring and light source, the electrode A and the electrode B are placed, with the coated surface of the electrode A facing the electrode B; non-delactose liquid milk A is added and immersed in the electrode plates, stirring is started, and the cooling and light control switches are turned on at the same time. The required light source is visible light and ultraviolet light with adjustable power and wavelength range, and a relative voltage or current is applied to the two electrode plates. The relative potential difference between the electrode A and the electrode B is 0-2V, and the current intensity is 0-100A. After a certain reaction time, liquid milk B is obtained for use; (4) The liquid milk B described in step (3) is filtered and impurities are removed under certain temperature conditions, and then sterilized to obtain liquid milk C.

2. The method for photocatalytically removing lactose from liquid milk according to claim 1, characterized in that: The TiO2 / AC composite material described in step (1) is prepared by using nano-TiO2 and food-grade activated carbon, directly using wet ball milling or dry ball milling under clean and pollution-free grinding conditions, drying after ball milling, and then sieving to obtain the obtained product.

3. The method for photocatalytically removing lactose from liquid milk according to claim 1, characterized in that: The TiO2 / AC composite material described in step (1) is prepared by a hydrothermal method as follows: ① Take titanium tetrachloride, ethylene glycol, and a specific surface area greater than 1000 m 2 / g of food-grade activated carbon, deionized water, the non-delactose liquid milk is called liquid milk A, and the above is reserved; ② put ethylene glycol into a stirred reactor with atmosphere protection, start stirring, and drop titanium tetrachloride under the protection of inert atmosphere, and continue stirring until the solution is uniform; ③ transfer the solution to a corrosion-resistant hydrothermal autoclave with inert atmosphere protection, put in activated carbon and deionized water, seal and replace with inert atmosphere; ④ react the reactor of step ③ at a reaction temperature of 100-200°C and a reaction time of 2-30 hours, and then cool to room temperature; ⑤ filter the product in step ④, wash with distilled water until the pH value of the washing liquid is neutral, and vacuum dry the filtered solid at 40-100°C for 6-12 hours, and then sieve with 100 mesh. The sieved material is TiO2 / AC composite material.

4. A method for photocatalytically removing lactose from liquid milk as claimed in claim 3, characterized in that In the steps of preparing TiO2 / AC composite materials by hydrothermal method: the volume ratio of titanium tetrachloride, ethylene glycol and deionized water described in step ① is 1:20~40:50~70, and each 1mL of titanium tetrachloride corresponds to 1g of food-grade activated carbon; the inert atmosphere described in steps ② and ③ is nitrogen or argon.

5. The method for photocatalytically removing lactose from liquid milk according to claim 1, characterized in that: The polyvinylidene fluoride described in step (2) is an analytically pure product or above without color additives; the mass ratio of the TiO2 / AC composite material to the polyvinylidene fluoride is 10:1~5:

1.

6. The method for photocatalytically removing lactose from liquid milk according to claim 1, characterized in that: The conductive substrate described in step (2) is made of any one of titanium, silver, copper, graphite, or an alloy of titanium, silver, and copper.

7. The method for photocatalytically removing lactose from liquid milk according to claim 1, characterized in that: In step (3), the area of ​​a single electrode corresponding to every 50 mL of liquid milk is greater than 3 square centimeters; and the reaction temperature is controlled to be no greater than 20°C.

8. The method for photocatalytically removing lactose from liquid milk according to claim 1, characterized in that: The reaction time in step (3) is 0.5 to 10 hours.

9. The method for photocatalytically removing lactose from liquid milk according to claim 1, characterized in that: The temperature required in step (4) is less than 20°C.