Multi-stage nano reaction system for preparing 0-sugar dairy product and preparation method of multi-stage nano reaction system

Abstract

The invention discloses a multistage nano reaction system for preparing 0-sugar dairy products and a preparation method of the multistage nano reaction system, lactose hydrolase, glucose oxidase and galactose oxidase are fixed on silicon dioxide nano particles through a nano reaction system technology, and an efficient enzyme-nano particle compound is formed. Through a multi-stage enzyme coupling reaction, efficient decomposition of lactose, galactose and glucose is realized, and finally the zero-sugar dairy product is prepared. Wherein the lactose hydrolase firstly decomposes lactose in the dairy product into galactose and glucose; then, glucose oxidase and galactose oxidase act on glucose and galactose respectively to further oxidize and decompose the glucose and the galactose; the process not only removes the sugar in the dairy product, but also increases the nutritional value and taste of the dairy product. The low-sugar and sugar-free milk product not only can meet the requirements of the market on low-sugar and sugar-free milk products, but also can provide healthy choices for diabetics and lactose intolerant people, and promotes the milk product industry to develop towards the low-sugar and healthy direction.

Description

Technical Field

[0001] The present invention belongs to the field of food processing, and in particular relates to a multi-stage nano-reaction system for preparing zero-sugar dairy products and a preparation method thereof. Background Art

[0002] As people's demand for healthy diets continues to increase, the market demand for low-sugar and sugar-free dairy products is also rising. Especially for diabetics and lactose-intolerant people, the sugar in traditional dairy products will bring health risks. The main sugar contained in dairy milk is lactose, which is a disaccharide formed by the condensation of one molecule of galactose and one molecule of glucose. When lactose enters the digestive tract, it is broken down by lactase into galactose and glucose. These two monosaccharides can be directly absorbed and utilized by the human body. At present, there are some low-sugar or sugar-free dairy products on the market, but most of these products rely on physical methods to remove part of the sugar, which is costly and inefficient; or they can only chemically decompose lactose, but cannot decompose the subsequent glucose and galactose products, and cannot completely achieve the effect of zero sugar. In short, these methods have low efficiency in removing sugar, high residue, high cost, and are difficult to meet consumers' health needs. Therefore, it is particularly important to develop a fast, efficient and low-pollution method for preparing zero-sugar dairy products. Therefore, there is an urgent need for a new technical means that can efficiently remove sugar from dairy products and provide true zero-sugar dairy products. Summary of the invention

[0003] Purpose of the invention: The technical problem to be solved by the present invention is that sugar in dairy products can bring health risks to diabetic patients and people with lactose intolerance. The existing processing methods for existing zero-sugar dairy products have the defects of low efficiency, high residue, high cost, etc., which cannot meet the production requirements of fast, efficient and low pollution. The present invention provides a multi-stage nano-reaction system for the preparation of zero-sugar dairy products and a preparation method thereof, which provides true zero-sugar dairy products by efficiently removing sugar from dairy products, and meets the market demand for low-sugar and sugar-free dairy products.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A method for preparing a multi-stage nano-reaction system for preparing zero-sugar dairy products comprises the following steps: S1. Preparation of high quality silica nanoparticles: Tetraethoxysilane is dissolved in ethanol, and water and ammonia catalyst are slowly added to perform hydrolysis and condensation reactions to form nanoparticles with uniform particle size and good dispersibility; S2. Functionalization treatment: Functionalizing the surface of the silica nanoparticles to obtain amino-functionalized silica nanoparticles; S3, enzyme coupling: Lactose hydrolase, glucose oxidase, and galactose oxidase molecules were separately bound to amino-functionalized silica nanoparticles using a cross-linking agent to form stable enzyme-nanoparticle complexes; S4. Forming a multi-level nano-reaction system: The enzyme-nanoparticle complex formed in step S3 is sequentially encapsulated in quartz columns and connected in series in sequence to obtain; The multi-stage nano-reaction system will be used to process dairy products to obtain zero-sugar dairy products.

[0005] Specifically, in step S1, the preparation process of the high-quality silicon dioxide nanoparticles is as follows: S1-1, tetraethyl orthosilicate and anhydrous ethanol are mixed in a volume ratio of 2-2.5:50 to obtain a mixed solution A; aqueous ammonia and anhydrous ethanol are mixed in a volume ratio of 1-1.5:50 to obtain a mixed solution B; tetraethyl orthosilicate and anhydrous ethanol are mixed in a volume ratio of 2-2.5:100 to obtain a mixed solution C; the three mixed solutions are placed in an oven for preheating to make their temperature the same as the temperature of the reaction system; S1-2, stirring and mixing the mixed solution A and the mixed solution B and allowing them to react fully; S1-3, after the reaction is completed, add 6-10% of the volume of the mixed solution obtained in step S1-2 with ammonia water, and continue the reaction; S1-4, then add the mixed solution C and continue the reaction for 2-4 hours, then stop, and obtain high-quality silica nanoparticles through centrifugal washing and purification.

[0006] Furthermore, in step S1-1, the three mixed solutions are preheated to 45-50° C. respectively; in step S1-2, the stirring and mixing speed is 800-1000 rpm, and the reaction time is 30-45 min; in step S1-3, the reaction is continued for 5-10 minutes.

[0007] Specifically, in step S2, the surface of the silicon dioxide nanoparticles is functionalized, and the specific process is as follows: S2-1, dispersing silica nanoparticles in anhydrous ethanol to form a uniform suspension, and the concentration of the suspension is controlled at 5-10 mg / mL; S2-2, adding aminosilane to the suspension, wherein the amount of aminosilane added is 1-5% (w / w) of the mass of the silica nanoparticles; S2-3, stirring the reaction at room temperature for 4-5 hours, with the stirring speed controlled at 600-800 rpm; S2-4, after the reaction is completed, removing unreacted aminosilane and solvent by centrifugation to obtain amino-functionalized silica nanoparticles; S2-5, washing the obtained amino-functionalized silica nanoparticles with anhydrous ethanol to remove residual reactants; S2-6. Drying the washed amino-functionalized silica nanoparticles.

[0008] Specifically, in step S3, the specific process of the enzyme coupling is as follows: S3-1, using N-(3-(dimethylamino)propyl)-N'-ethylcarbodiimide hydrochloride crystals and N-hydroxysuccinimide to activate silica colloidal nanoparticles; S3-2, covalently bonding the activated silica colloidal nanoparticles using a cross-linking agent, glutaraldehyde; S3-3, respectively, mixing lactose hydrolase, glucose oxidase and galactose oxidase with the colloidal nanoparticles of step S3-2 in the presence of a cross-linking agent to react completely, and then gently washing with a buffer solution to obtain a stable enzyme-nanoparticle complex.

[0009] Furthermore, in step S3-1, the mass ratio of N-(3-(dimethylamino)propyl)-N'-ethylcarbodiimide hydrochloride crystals and N-hydroxysuccinimide is 0.5-1:1, and the concentrations are 8-12 mM and 4-6 mM, respectively.

[0010] Furthermore, in step S3-2, the mass volume concentration of glutaraldehyde is controlled at 0.5-1.5%.

[0011] Specifically, in step S4, the specific process of encapsulating the enzyme-nanoparticle complex in the quartz column in sequence is as follows: S4-1, drying the three enzyme-nanoparticle complexes obtained in step S3, and filling the dried enzyme-nanoparticle complex blocks into three quartz columns in the order of lactose, galactose, and glucose substrates, each quartz column having a diameter of 10-12 cm and a height of 50-60 cm; S4-2. Use a filter membrane to encapsulate both ends of the quartz column to ensure that the molecules in the dairy products can pass through the filter membrane into the reaction system, while the enzyme-nanoparticle complex is confined inside the quartz column and cannot move. The pore size of the filter membrane is controlled at 0.2-0.22 microns.

[0012] Specifically, when the multi-stage nano-reaction system is used to process dairy products, the dairy products are pre-treated and heated to 45-50°C. The pre-heated dairy products are passed through the multi-stage nano-reaction system at a speed of 100-120 ml / min, and enter the reaction system through the filter membrane. First, they come into contact with the lactose hydrolase fixed on the silica nanoparticles. The lactose hydrolase decomposes lactose into galactose and glucose. Then, the dairy products flow through the area containing glucose oxidase and galactose oxidase. These two enzymes further oxidize glucose and galactose into harmless substances such as gluconic acid and galactonic acid, respectively. After being treated by the multi-stage nano-reaction system, the sugar in the dairy products is effectively decomposed, and the resulting zero-sugar dairy products are collected.

[0013] Furthermore, the multi-stage nano-reaction system for preparing zero-sugar dairy products prepared by the above-mentioned preparation method is also within the protection scope of the present invention. Beneficial Effects

[0014] (1) The present invention is capable of preparing zero-sugar dairy products based on a multi-stage nano-reaction system. Through the nano-reaction system technology, lactose hydrolase, glucose oxidase and galactose oxidase are fixed on silica nanoparticles to form an efficient enzyme-nanoparticle complex. Through the multi-stage enzyme coupling reaction, the efficient decomposition of lactose, galactose and glucose is achieved, and finally zero-sugar dairy products are prepared. Specifically, lactose hydrolase first decomposes lactose in dairy products into galactose and glucose. Subsequently, glucose oxidase and galactose oxidase act on glucose and galactose respectively, further oxidizing and decomposing them. This process not only removes sugar from dairy products, but also increases the nutritional value and taste of dairy products. This technology can not only meet the market demand for low-sugar and sugar-free dairy products, but also provide healthy choices for diabetic patients and lactose-intolerant people, and promote the development of the dairy industry towards low-sugar and healthy directions.

[0015] (2) The reaction system of the present invention can prepare true zero-sugar dairy products, meeting the needs of diabetics and lactose-intolerant people for sugar-free dairy products. However, most products on the market rely on physical methods to remove part of the sugar, which is costly and inefficient; or can only chemically decompose lactose, but cannot decompose subsequent glucose and galactose products, and cannot completely achieve the zero-sugar effect.

[0016] (3) The catalytic system of the present invention is efficient, stable and highly selective. The present invention achieves efficient decomposition of lactose, galactose and glucose through a multi-stage nano-reaction system, and the catalytic efficiency is much higher than that of traditional methods. The enzyme-nanoparticle complex is highly selective and can accurately decompose the target sugar and reduce unnecessary side reactions. The enzyme immobilized on the silica nanoparticles has better stability and reusability, which prolongs the service life of the enzyme.

[0017] (4) The present invention is highly safe and environmentally friendly. The entire preparation process does not produce harmful byproducts, is environmentally friendly, and complies with the principles of green chemistry. Since immobilized enzymes are used, the residue of free enzymes in the product is avoided, thereby improving the safety of the product.

[0018] (5) The nano-reaction system of the present invention has the advantages of high efficiency and stability, and is suitable for large-scale production in the future. By precisely controlling the reaction conditions (such as pH value, temperature, reaction time and reactant concentration), the nano-catalytic system can be precisely adjusted to ensure its reliability and efficiency in practical applications. The application of this technology can not only improve production efficiency and reduce production costs, but also ensure product quality and safety, providing new ideas and technical support for the development of the dairy industry.

[0019] (6) The present invention is cost-effective, easy to operate and widely applicable in industry. By precisely controlling the reaction conditions, the production cost can be reduced, the production efficiency can be improved, and the economy is good. The design of the multi-stage nano-reaction system simplifies the production process and is easy to operate and maintain. This technology is not only suitable for dairy products, but can also be extended to the removal of sugar from other beverages, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0021] Figure 1 It is the technical roadmap of the multi-stage nano-reaction system used for preparing zero-sugar dairy products of the present invention.

[0022] Figure 2 It is a schematic diagram of the synthesis of high-quality silica nanoparticles of the present invention.

[0023] Figure 3 It is an electron microscope image of the high-quality silicon dioxide nanoparticles of the present invention.

[0024] Figure 4 It is a schematic diagram of the industrial structure of the multi-stage nano-reaction system used for preparing zero-sugar dairy products of the present invention. DETAILED DESCRIPTION

[0025] The present invention can be better understood with reference to the following examples.

[0026] Combination Figure 1 As shown, the preparation method of the multi-stage nano-reaction system for preparing zero-sugar dairy products of the present invention comprises the following steps: S1. Preparation of high quality silica nanoparticles: Tetraethoxysilane is dissolved in ethanol, and water and ammonia catalyst are slowly added to perform hydrolysis and condensation reactions to form nanoparticles with uniform particle size and good dispersibility; S2. Functionalization treatment: Functionalizing the surface of the silica nanoparticles to obtain amino-functionalized silica nanoparticles; S3, enzyme coupling: Lactose hydrolase, glucose oxidase, and galactose oxidase molecules were separately bound to amino-functionalized silica nanoparticles using a cross-linking agent to form stable enzyme-nanoparticle complexes; S4. Forming a multi-level nano-reaction system: The enzyme-nanoparticle complex formed in step S3 is sequentially encapsulated in quartz columns and connected in series in sequence to obtain; The multi-stage nano-reaction system will be used to process dairy products to obtain zero-sugar dairy products.

[0027] Example 1: Synthesis of enzyme-nanoparticle complexes (1) Objective: To synthesize enzyme-nanoparticle complexes for use in subsequent multi-stage nanoreaction systems to achieve efficient decomposition of sugars in milk and prepare zero-sugar milk.

[0028] (2) Solution preparation: Mixture A: Dissolve 2 ml tetraethyl orthosilicate (TEOS) in 50 ml anhydrous ethanol. Mixture B: Dissolve 10 ml ammonia water in 50 ml anhydrous ethanol. Mixture C: Dissolve 2 ml tetraethyl orthosilicate in 100 ml anhydrous ethanol. Aminosilane solution: 3-aminopropyltriethoxysilane (APTES), concentration is 1-5% (w / v). Activation solution: N-(3-(dimethylamino)propyl)-N'-ethylcarbodiimide hydrochloride crystals (EDC) and N-hydroxysuccinimide (NHS), concentrations are 10 mM and 5 mM, respectively. Crosslinker solution: glutaraldehyde, concentration is 1% (w / v). Buffer solution: phosphate buffer solution (PBS), pH 7.4.

[0029] (3) Prepare reaction vessels and instruments: 1 three-necked flask, 500 ml. Several centrifuge tubes, 50 ml. 1 centrifuge, 10,000 rpm. 1 vacuum drying oven, adjustable temperature. 1 microfluidic chip, for preparing monodisperse emulsion droplets. 1 stirrer, adjustable speed. 1 oven, adjustable temperature.

[0030] (4) Preparation of silica nanoparticles: Place the mixed solutions A, B, and C in an oven for preheating respectively, so that their temperatures are the same as the temperature of the reaction system. Add solution A and solution B into a three-necked flask with a mechanical stirrer, and start stirring at the same time, with a speed of about 800 rpm. After 30 minutes of reaction, add 10 ml of ammonia water from the side port of the three-necked flask. After another 5-10 minutes of reaction, add solution C to the system, and continue the reaction for 2 hours before stopping. High-quality silica nanoparticles can be obtained after centrifugal washing and purification. The reaction principle is as follows: Figure 2 As shown, the obtained silica nanoparticle sample is Figure 3 shown.

[0031] (5) Functionalization of nanoparticles: Disperse silica nanoparticles in anhydrous ethanol to form a uniform suspension. Add aminosilane (3-aminopropyltriethoxysilane, APTES) to the suspension and stir the reaction at room temperature for 4 hours. After the reaction is completed, remove the unreacted aminosilane and solvent by centrifugation. Wash the obtained amino-functionalized silica nanoparticles with anhydrous ethanol three times to remove residual reactants. Dry the washed amino-functionalized silica nanoparticles in a vacuum drying oven to obtain stable functionalized nanoparticles.

[0032] (6) Coupling of enzymes with functionalized nanoparticles: Silica colloidal nanoparticles were activated using N-(3-(dimethylamino)propyl)-N'-ethylcarbodiimide hydrochloride crystals (EDC) and N-hydroxysuccinimide (NHS). Covalent bonding was performed using a cross-linking agent (such as glutaraldehyde). Enzymes such as lactose hydrolase, glucose oxidase, and galactose oxidase were mixed with functionalized silica colloidal nanoparticles in the presence of a cross-linking agent and reacted overnight. After gentle washing with a buffer solution, a stable enzyme-nanoparticle complex was finally obtained.

[0033] Example 2: Preparation of 0-sugar high-calcium buffalo milk (1) Objective: To prepare zero-sugar, high-calcium buffalo milk to meet the needs of diabetic patients and lactose-intolerant people while providing rich calcium.

[0034] (2) Solution preparation: high calcium buffalo milk; phosphate buffer solution (PBS), pH adjusted to 7.4, to maintain enzyme activity and stability.

[0035] (3) Required instruments: multi-stage nano-reaction system (including quartz columns containing lactose hydrolase, glucose oxidase and galactose oxidase); centrifuge (speed up to 10,000 rpm, used for separation and purification); vacuum drying oven (used for drying); constant temperature water bath (temperature adjustable, used for preheating and controlling reaction temperature); filter (used to filter solid particles in high-calcium buffalo milk to ensure product purity). The industrial structure of the multi-stage nano-reaction system used for the preparation of zero-sugar dairy products is as follows: Figure 4 As shown. Column 1 is a quartz column containing a lactose hydrolase-nanoparticle complex to achieve galactose decomposition. Column 2 is a quartz column containing a galactose oxidase-nanoparticle complex to achieve galactose decomposition. Column 3 is a quartz column containing a glucose oxidase-nanoparticle complex to achieve glucose decomposition. High calcium buffalo milk flows from left to right.

[0036] (4) Pretreatment: Heat high-calcium buffalo milk to 45°C for 10 to 30 minutes to increase enzyme activity and reduce microbial contamination in milk.

[0037] (5) Flowing through the reaction system: The pretreated milk is passed through the multi-stage nano-reaction system at a flow rate of 100 mL / min, passes through a 0.2 μm filter membrane into the reaction system, and comes into contact with the lactose hydrolase immobilized on the silica nanoparticles.

[0038] (6) Sugar breakdown: Lactose hydrolase breaks down lactose into galactose and glucose. The high-calcium buffalo milk then flows through an area containing glucose oxidase and galactose oxidase. These two enzymes further oxidize glucose and galactose into harmless gluconic acid and galactonic acid and carbon dioxide.

[0039] (7) Processing time control: The processing time of high-calcium buffalo milk in the multi-stage nanoreaction system is usually controlled within 1 to 4 hours, depending on the initial sugar concentration of the milk and the required sugar removal efficiency.

[0040] (8) Collecting zero-sugar, high-calcium buffalo milk: After being treated by the multi-stage nano-reaction system, the sugar in the milk is effectively decomposed, and the resulting zero-sugar, high-calcium buffalo milk is collected. The treated milk can be further filtered or centrifuged to remove any residual nanoparticles.

[0041] (9) Post-processing: The obtained zero-sugar, high-calcium buffalo milk is cooled to room temperature and packaged and sterilized as needed to ensure product quality and safety.

[0042] The present invention provides a multi-stage nano-reaction system for preparing zero-sugar dairy products and a method for preparing the same. There are many methods and approaches to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention. All components not specified in this embodiment can be implemented using existing technologies.

Claims

1. A method for preparing a multi-stage nano-reaction system for preparing zero-sugar dairy products, characterized in that: The steps include: S1. Preparation of high quality silica nanoparticles: Tetraethoxysilane is dissolved in ethanol, and water and ammonia catalyst are slowly added to perform hydrolysis and condensation reactions to form nanoparticles with uniform particle size and good dispersibility; S2. Functionalization treatment: Functionalizing the surface of the silica nanoparticles to obtain amino-functionalized silica nanoparticles; S3, enzyme coupling: Lactose hydrolase, glucose oxidase, and galactose oxidase molecules were separately bound to amino-functionalized silica nanoparticles using a cross-linking agent to form stable enzyme-nanoparticle complexes; S4. Forming a multi-level nano-reaction system: The enzyme-nanoparticle complex formed in step S3 is sequentially encapsulated in quartz columns and connected in series in sequence to obtain; The multi-stage nano-reaction system will be used to process dairy products to obtain zero-sugar dairy products.

2. The method for preparing a multi-stage nano-reaction system for preparing zero-sugar dairy products according to claim 1, characterized in that: In step S1, the preparation process of the high-quality silicon dioxide nanoparticles is as follows: S1-1, tetraethyl orthosilicate and anhydrous ethanol are mixed in a volume ratio of 2-2.5:50 to obtain a mixed solution A; aqueous ammonia and anhydrous ethanol are mixed in a volume ratio of 1-1.5:50 to obtain a mixed solution B; tetraethyl orthosilicate and anhydrous ethanol are mixed in a volume ratio of 2-2.5:100 to obtain a mixed solution C; the three mixed solutions are placed in an oven for preheating to make their temperature the same as the temperature of the reaction system; S1-2, stirring and mixing the mixed solution A and the mixed solution B and allowing them to react fully; S1-3, after the reaction is completed, add 6-10% of the volume of the mixed solution obtained in step S1-2 with ammonia water, and continue the reaction; S1-4, then add the mixed solution C and continue the reaction for 2-4 hours, then stop, and obtain high-quality silica nanoparticles through centrifugal washing and purification.

3. The method for preparing a multi-stage nano-reaction system for preparing zero-sugar dairy products according to claim 2, characterized in that: In step S1-1, the three mixed solutions are preheated to 45-50° C. respectively; in step S1-2, the stirring and mixing speed is 800-1000 rpm, and the reaction time is 30-45 min; in step S1-3, the reaction is continued for 5-10 minutes.

4. The method for preparing a multi-stage nano-reaction system for preparing zero-sugar dairy products according to claim 1, characterized in that: In step S2, the surface of the silicon dioxide nanoparticles is functionalized, and the specific process is as follows: S2-1, dispersing silica nanoparticles in anhydrous ethanol to form a uniform suspension, and the concentration of the suspension is controlled at 5-10 mg / mL; S2-2, adding aminosilane to the suspension, wherein the amount of aminosilane added is 1-5% (w / w) of the mass of the silica nanoparticles; S2-3, stirring the reaction at room temperature for 4-5 hours, with the stirring speed controlled at 600-800 rpm; S2-4, after the reaction is completed, removing unreacted aminosilane and solvent by centrifugation to obtain amino-functionalized silica nanoparticles; S2-5, washing the obtained amino-functionalized silica nanoparticles with anhydrous ethanol to remove residual reactants; S2-6. Drying the washed amino-functionalized silica nanoparticles.

5. The method for preparing a multi-stage nano-reaction system for preparing zero-sugar dairy products according to claim 1, characterized in that: In step S3, the specific process of the enzyme coupling is as follows: S3-1, using N-(3-(dimethylamino)propyl)-N'-ethylcarbodiimide hydrochloride crystals and N-hydroxysuccinimide to activate silica colloidal nanoparticles; S3-2, covalently bonding the activated silica colloidal nanoparticles using a cross-linking agent, glutaraldehyde; S3-3, respectively, mixing lactose hydrolase, glucose oxidase and galactose oxidase with the colloidal nanoparticles of step S3-2 in the presence of a cross-linking agent to react completely, and then gently washing with a buffer solution to obtain a stable enzyme-nanoparticle complex.

6. The method for preparing a multi-stage nano-reaction system for preparing zero-sugar dairy products according to claim 5, characterized in that: In step S3-1, the mass ratio of N-(3-(dimethylamino)propyl)-N'-ethylcarbodiimide hydrochloride crystals and N-hydroxysuccinimide is 0.5-1:1, and the concentrations are 8-12 mM and 4-6 mM, respectively.

7. The method for preparing a multi-stage nano-reaction system for preparing zero-sugar dairy products according to claim 6, characterized in that: In step S3-2, the mass volume concentration of glutaraldehyde is controlled at 0.5-1.5%.

8. The method for preparing a multi-stage nano-reaction system for preparing zero-sugar dairy products according to claim 1, characterized in that: In step S4, the specific process of encapsulating the enzyme-nanoparticle complex in the quartz column in sequence is as follows: S4-1, drying the three enzyme-nanoparticle complexes obtained in step S3, and filling the dried enzyme-nanoparticle complex blocks into three quartz columns in the order of lactose, galactose, and glucose substrates, each quartz column having a diameter of 10-12 cm and a height of 50-60 cm; S4-2. Use a filter membrane to encapsulate both ends of the quartz column to ensure that the molecules in the dairy products can pass through the filter membrane into the reaction system, while the enzyme-nanoparticle complex is confined inside the quartz column and cannot move. The pore size of the filter membrane is controlled at 0.2-0.22 microns.

9. The method for preparing a multi-stage nano-reaction system for preparing zero-sugar dairy products according to claim 1, characterized in that: The dairy products are pretreated and heated to 45-50°C. The preheated dairy products are passed through a multi-stage nano-reaction system at a speed of 100-120 ml / min, and enter the reaction system through a filter membrane. They first come into contact with lactose hydrolase immobilized on silica nanoparticles. Lactose hydrolase decomposes lactose into galactose and glucose. Then, the dairy products flow through areas containing glucose oxidase and galactose oxidase. These two enzymes further oxidize glucose and galactose into harmless substances such as gluconic acid and galactonic acid, respectively. After being treated by the multi-stage nano-reaction system, the sugar in the dairy products is effectively decomposed, and the resulting zero-sugar dairy products are collected.

10. A multi-stage nano-reaction system for preparing zero-sugar dairy products prepared by the preparation method according to any one of claims 1 to 9.

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