Crystallization method of carnosine

Abstract

The invention relates to the technical field of carnosine, in particular to a crystallization method of carnosine, which comprises the following steps: S1, preparation of a base material: the base material comprises the following raw materials in percentage by mass: 4-6% of carnosine, 0.06-0.08% of histidine, 0.1-0.3% of beta-alanine, 0.4-0.6% of fiber material and the balance of water. According to the invention, 1-butyl-3-methylimidazolium hexafluorophosphate can dissolve cellulose of phoenix tree leaves to expose more active sites, the addition of polyethylene glycol can improve the dispersion uniformity of the fiber material, the microcrystalline cellulose surface in the fiber material can be used as a template, carnosine molecules are guided to be arranged according to specific crystal lattices through an interface induction effect, and the surface of the carnosine molecules can be used as a template. The crystal defects are reduced, the nucleation energy barrier is reduced, the crystal nucleus formation is accelerated, and the purposes of improving the purity and the yield of the carnosine crystal preparation are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of carnosine, in particular to a carnosine crystallization method. Background Art

[0002] Carnosine is a crystalline solid that has antioxidant and anti-glycation effects. It can protect cells from free radical damage and reduce aging-related cell changes. In the cosmetics field, it can be used to delay skin aging. In the food industry, it can be used as an antioxidant to preserve freshness.

[0003] In the prior art, during the crystallization process of carnosine, the interactions between carnosine molecules are complex, the molecules are crowded, and it is difficult to form a regular lattice structure, thereby affecting the quality of the carnosine crystallization. Based on this, the present invention provides a method for crystallizing carnosine. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for crystallizing carnosine. The carnosine prepared by the method not only has good purity performance, but also has excellent yield performance.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for crystallizing carnosine, characterized in that it comprises the following steps: S1: Preparation of a base material, wherein the raw materials of the base material include water, carnosine powder, histidine, β-alanine, and fiber material, wherein the mass percentage of each raw material is: 4-6% carnosine powder, 0.06-0.08% histidine, 0.1-0.3% β-alanine, 0.4-0.6% fiber material, and the balance is water. After mixing the raw materials, the base material is purified by a membrane system and electrodialysis to obtain the base material; S2: Pretreatment: the base material is decolorized and then concentrated under reduced pressure to obtain a concentrated base material; The temperature of the reduced pressure concentration treatment is 40-80°C, the vacuum degree is -0.1Mpa, and the treatment time is 30-40min; S3: Preparation of finished product: adding ethanol to the concentrated base material for crystallization, followed by crystal growth, filtration and drying to obtain carnosine.

[0006] Furthermore, the fiber material is prepared by the following method: fresh sycamore leaves are selected, immersed in clean water for 2 to 4 hours, then drained and dried, and after drying, ground to a particle size of 2 to 10 μm to obtain powder, the powder and sodium hydroxide solution are added to a water bath and mixed, stirred evenly, and then set to heat to 86 to 88° C. and react at a constant temperature for 1 to 3 hours. The obtained product is filtered, and the precipitate is taken and washed with deionized water to obtain a coarse material for standby use.

[0007] Furthermore, the coarse material and the mixed liquid are added to a mixer, which is set at 120-160 r / min and stirred for 10-20 min. The product obtained by stirring is added to a ball mill, and the ball milling time is 6-10 min. The ball milling is performed 3-5 times with an interval of 2-4 min. The product obtained by ball milling is added to a centrifuge, and the centrifuge is set at 3000-5000 r / min and centrifuged for 4-6 min. A precipitate is taken from the product obtained by centrifugation, and the precipitate is sent to an oven, which is set at 40-50°C and dried for 3-6 h. The obtained product is ground to obtain a fiber material with a grinding particle size of 2-10 μm.

[0008] Furthermore, the mass ratio of the powder to the sodium hydroxide solution is 1: (6-8), the mass concentration of the sodium hydroxide solution is 3-5%, and the mass ratio of the coarse material to the mixed liquid is 1: (1.2-1.4).

[0009] Furthermore, the mixed liquid is prepared by mixing 1-butyl-3-methylimidazolium hexafluorophosphate and polyethylene glycol, and the mass ratio of 1-butyl-3-methylimidazolium hexafluorophosphate to polyethylene glycol is 1:(0.1-0.2).

[0010] Furthermore, the decolorization method is as follows: activated carbon is added to the base material, and a stirring adsorption treatment is performed for 2 to 4 hours. After the treatment is completed, the activated carbon is filtered to remove the activated carbon to complete the decolorization treatment, wherein the mass of the activated carbon is 4 to 6% of the mass of the base material, and the activated carbon is pretreated before being added to the base material.

[0011] Furthermore, the pretreatment method of the activated carbon is as follows: the activated carbon is dried and ground to a powder particle size of 60 to 100 μm to obtain activated carbon powder, the activated carbon powder and the treatment liquid are added to a mixer, the mixer is set to 200 to 300 r / min and stirred for 20 to 30 minutes, the stirred product is washed with deionized water, and then sent to a tubular furnace, the tubular furnace is set to a heating rate of 4 to 6°C / min, the temperature is raised to 280 to 320°C, and the temperature is kept warm for 30 to 40 minutes. During the treatment process, water vapor is introduced into the tubular furnace to complete the pretreatment of the activated carbon, wherein the mass of the treatment liquid is 2 to 4 times the mass of the activated carbon powder.

[0012] Furthermore, the treatment liquid is prepared by mixing hydrogen peroxide, nitric acid, disodium ethylenediaminetetraacetic acid and ammonia water, the mass ratio of hydrogen peroxide, nitric acid, disodium ethylenediaminetetraacetic acid and ammonia water is 1: (2-3): (0.03-0.05): (0.1-0.3), the mass concentration of hydrogen peroxide is 2-4%, and the mass concentration of ammonia water is 20-22%.

[0013] Furthermore, the method for preparing the finished product is as follows: ethanol is added dropwise to the concentrated base material while maintaining a stirring state, the temperature is set to 40-60°C during the addition, the addition of ethanol is stopped after crystals appear, and a crystal growing process is performed, and the remaining ethanol is added dropwise after the crystal growing process is completed. After the addition process is completed, the temperature is set to 42-46°C, and the process is stirred at a constant temperature for 1-3 hours. The obtained product is filtered to obtain crystals, the crystals are rinsed with ethanol, and then the crystals are placed in an oven, and the oven is set at 70-90°C for drying for 20-40 minutes to obtain carnosine.

[0014] Furthermore, the mass of ethanol is 8 to 12 times the mass of carnosine powder, and the crystal growth treatment time is 40 to 60 minutes.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, in the process of preparing carnosine crystals, a fiber material is used to prepare a base material. After the fiber material is processed using sycamore leaves as a raw material, 1-butyl-3-methylimidazole hexafluorophosphate can dissolve the cellulose in the sycamore leaves, exposing more active sites. The addition of polyethylene glycol can improve the uniformity of the dispersion of the fiber material. The surface of the microcrystalline cellulose in the fiber material can serve as a template. Through the interfacial induction effect, the carnosine molecules are guided to arrange according to a specific lattice, thereby reducing its crystal defects, lowering the nucleation energy barrier, and accelerating the formation of crystal nuclei, thereby achieving the purpose of improving the purity and yield of the carnosine crystal preparation.

[0016] 2. In the present invention, by pre-treating the activated carbon in the decolorization step, the activated carbon can increase its specific surface area after being ground into fine powder, exposing more micropores on its surface, thereby improving the adsorption capacity. The use of the treatment liquid can generate oxygen-containing functional groups on the surface of the activated carbon, thereby enhancing the adsorption capacity of pigment molecules. The introduction of water vapor can regulate the hydrophilic balance and enhance the adsorption performance of zwitterions, thereby making the adsorption treatment of impurities in the crystallization preparation of carnosine more thorough, further improving the purity and yield of the carnosine crystallization preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of a method for crystallizing carnosine is proposed for the invention; Figure 2 The present invention proposes a fiber material preparation flow chart for a method for crystallizing carnosine. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] It should be noted that the raw materials used in the following examples are all commercially available raw materials.

[0020] Example 1: S1: Preparation of base material. The raw materials of the base material include water, carnosine powder, histidine, β-alanine, and fiber material. The mass percentage of each raw material is: 4% carnosine powder, 0.06% histidine, 0.1% β-alanine, 0.4% fiber material, and the balance is water. After mixing the raw materials, the base material is purified by a membrane system and electrodialysis to obtain the base material. The fiber material is prepared by the following method: fresh sycamore leaves are selected, immersed in clean water for 2 hours, then drained and dried, and then ground to a particle size of 2 μm to obtain a powder. The powder and sodium hydroxide solution are added to a water bath and mixed. After stirring evenly, the temperature is set to 86°C and the reaction is carried out at a constant temperature for 1 hour. The obtained product is filtered, and the precipitate is taken and washed with deionized water to obtain a coarse material for standby use. The coarse material and the mixed solution are added to a mixer, and the mixer is set to 120 r / min and stirred for 10 minutes. The obtained The product was added to a ball mill and subjected to ball milling for 6 minutes, and the ball milling was repeated 3 times with an interval of 2 minutes. The product obtained by ball milling was added to a centrifuge and centrifuged at 3000 r / min for 4 minutes. A precipitate was taken from the product obtained by centrifugation and placed in an oven, which was set at 40° C. and dried for 3 hours. The obtained product was ground to obtain a fiber material with a grinding particle size of 2 μm. The mass ratio of the powder to the sodium hydroxide solution was 1:6, the mass concentration of the sodium hydroxide solution was 3%, and the mass ratio of the coarse material to the mixed solution was 1:1.2. The mixed solution is prepared by mixing 1-butyl-3-methylimidazolium hexafluorophosphate and polyethylene glycol, wherein the mass ratio of 1-butyl-3-methylimidazolium hexafluorophosphate to polyethylene glycol is 1:0.1; S2: Pretreatment: the base material is decolorized and then concentrated under reduced pressure to obtain a concentrated base material; The decolorization method is as follows: adding activated carbon to the base material, performing stirring adsorption treatment for 2 hours, and after the treatment is completed, filtering to remove the activated carbon to complete the decolorization treatment, wherein the mass of the activated carbon is 4% of the mass of the base material, and the activated carbon is pretreated before being added to the base material; The pretreatment method of activated carbon is as follows: the activated carbon is dried and ground to a powder particle size of 60 μm to obtain activated carbon powder, the activated carbon powder and the treatment liquid are added to a mixer, the mixer is set to 200 r / min and stirred for 20 minutes, the stirred product is washed with deionized water, and then sent to a tubular furnace, the tubular furnace is set to a heating rate of 4°C / min, the temperature is raised to 280°C, and the temperature is kept for 30 minutes, water vapor is introduced into the tubular furnace during the treatment process to complete the pretreatment of the activated carbon, wherein the mass of the treatment liquid is twice the mass of the activated carbon powder, the treatment liquid is prepared by mixing hydrogen peroxide, nitric acid, disodium ethylenediaminetetraacetic acid and ammonia water, the mass ratio of hydrogen peroxide, nitric acid, disodium ethylenediaminetetraacetic acid and ammonia water is 1:2:0.03:0.1, the mass concentration of hydrogen peroxide is 2%, and the mass concentration of ammonia water is 20%; The temperature of the reduced pressure concentration treatment was 40°C, the vacuum degree was -0.1 MPa, and the treatment time was 30 min; S3: Preparation of finished product: adding ethanol to the concentrated base material for crystallization, followed by crystal growth, filtration, and drying to obtain carnosine; The method for preparing the finished product is as follows: ethanol is added dropwise to the concentrated base material and stirred, the temperature is set to 40°C during the addition, the addition of ethanol is stopped after crystals appear, and crystal growing is carried out, the remaining ethanol is added dropwise after the crystal growing is completed, the temperature is set to 42°C after the addition is completed, and the constant temperature stirring is carried out for 1 hour, the obtained product is filtered to obtain crystals, the crystals are rinsed with ethanol, and then the crystals are sent to an oven, the oven is set to 70°C for drying for 20 minutes to obtain carnosine, wherein the mass of ethanol is 8 times the mass of carnosine powder, and the crystal growing time is 40 minutes.

[0021] Example 2: S1: Preparation of base material. The raw materials of the base material include water, carnosine powder, histidine, β-alanine, and fiber material. The mass percentage of each raw material is: 5% carnosine powder, 0.07% histidine, 0.2% β-alanine, 0.5% fiber material, and the balance is water. After mixing the raw materials, the base material is purified by a membrane system and electrodialysis to obtain the base material. The fiber material is prepared by the following method: fresh sycamore leaves are selected, immersed in clean water for 3 hours, then drained and dried, and then ground to a particle size of 6 μm to obtain a powder. The powder and sodium hydroxide solution are added to a water bath and mixed. After stirring evenly, the temperature is set to 87°C and the reaction is carried out at a constant temperature for 2 hours. The obtained product is filtered, and the precipitate is taken and washed with deionized water to obtain a coarse material for standby use. The coarse material and the mixed solution are added to a mixer, and the mixer is set to 140 r / min and stirred for 15 minutes. The product obtained by stirring is The raw materials were added into a ball mill, and the ball milling time was 8 minutes. The ball milling was performed 4 times with an interval of 3 minutes. The product obtained by ball milling was added into a centrifuge, and the centrifuge was set at 4000r / min for 5 minutes. The precipitate was taken from the product obtained by centrifugation, and the precipitate was sent to an oven, and the oven was set at 45°C for drying for 4.5 hours. The obtained product was ground to obtain a fiber material with a grinding particle size of 6μm. The mass ratio of the powder to the sodium hydroxide solution was 1:7, the mass concentration of the sodium hydroxide solution was 4%, and the mass ratio of the coarse material to the mixed liquid was 1:1.3. The mixed solution is prepared by mixing 1-butyl-3-methylimidazolium hexafluorophosphate and polyethylene glycol, wherein the mass ratio of 1-butyl-3-methylimidazolium hexafluorophosphate to polyethylene glycol is 1:0.15; S2: Pretreatment: the base material is decolorized and then concentrated under reduced pressure to obtain a concentrated base material; The decolorization method is as follows: adding activated carbon to the base material, performing stirring and adsorption treatment for 3 hours, and after the treatment is completed, filtering to remove the activated carbon to complete the decolorization treatment, wherein the mass of the activated carbon is 5% of the mass of the base material, and the activated carbon is pretreated before being added to the base material; The pretreatment method of activated carbon is as follows: the activated carbon is dried and ground to a powder particle size of 80 μm to obtain activated carbon powder, the activated carbon powder and the treatment liquid are added to a mixer, the mixer is set to 250 r / min and stirred for 25 minutes, the stirred product is washed with deionized water, and then sent to a tube furnace, the tube furnace is set to a heating rate of 5°C / min, the temperature is raised to 300°C, and the temperature is kept for 35 minutes, water vapor is introduced into the tube furnace during the treatment process to complete the pretreatment of the activated carbon, wherein the mass of the treatment liquid is 3 times the mass of the activated carbon powder, the treatment liquid is prepared by mixing hydrogen peroxide, nitric acid, disodium ethylenediaminetetraacetic acid and ammonia water, the mass ratio of hydrogen peroxide, nitric acid, disodium ethylenediaminetetraacetic acid and ammonia water is 1:2.5:0.04:0.2, the mass concentration of hydrogen peroxide is 34%, and the mass concentration of ammonia water is 21%; The temperature of the reduced pressure concentration treatment was 60°C, the vacuum degree was -0.1 MPa, and the treatment time was 35 min; S3: Preparation of finished product: adding ethanol to the concentrated base material for crystallization, followed by crystal growth, filtration, and drying to obtain carnosine; The method for preparing the finished product is as follows: ethanol is added dropwise to the concentrated base material and stirred, the temperature is set to 50°C during the addition, the addition of ethanol is stopped after crystals appear, and crystal growing is carried out, the remaining ethanol is added dropwise after the crystal growing is completed, the temperature is set to 44°C after the addition is completed, and the constant temperature stirring is carried out for 2 hours, the obtained product is filtered to obtain crystals, the crystals are rinsed with ethanol, and then the crystals are sent to an oven, the oven is set to 80°C for drying for 30 minutes to obtain carnosine, wherein the mass of ethanol is 10 times the mass of carnosine powder, and the crystal growing time is 50 minutes.

[0022] Example 3: S1: Preparation of base material. The raw materials of the base material include water, carnosine powder, histidine, β-alanine, and fiber material. The mass percentage of each raw material is: 6% carnosine powder, 0.08% histidine, 0.3% β-alanine, 0.6% fiber material, and the balance is water. After mixing the raw materials, the base material is purified by a membrane system and electrodialysis to obtain the base material. The fiber material is prepared by the following method: fresh sycamore leaves are selected, immersed in clean water for 4 hours, then drained and dried, and then ground to a particle size of 10 μm to obtain a powder. The powder and sodium hydroxide solution are added to a water bath and mixed. After stirring evenly, the temperature is set to 88°C and the reaction is carried out at a constant temperature for 3 hours. The obtained product is filtered, and the precipitate is taken and washed with deionized water to obtain a coarse material for standby use. The coarse material and the mixed solution are added to a mixer, and the mixer is set to 160 r / min and stirred for 20 minutes. The obtained The product was added to a ball mill and subjected to a ball milling treatment for 10 minutes. The ball milling treatment was repeated 5 times with an interval of 4 minutes. The product obtained by ball milling was added to a centrifuge and centrifuged at 5000 r / min for 6 minutes. A precipitate was taken from the product obtained by centrifugation and placed in an oven at 50° C. for drying for 6 hours. The obtained product was ground to obtain a fiber material with a grinding particle size of 10 μm. The mass ratio of the powder to the sodium hydroxide solution was 1:8, the mass concentration of the sodium hydroxide solution was 5%, and the mass ratio of the coarse material to the mixed solution was 1:1.4. The mixed solution is prepared by mixing 1-butyl-3-methylimidazolium hexafluorophosphate and polyethylene glycol, wherein the mass ratio of 1-butyl-3-methylimidazolium hexafluorophosphate to polyethylene glycol is 1:0.2; S2: Pretreatment: the base material is decolorized and then concentrated under reduced pressure to obtain a concentrated base material; The decolorization method is as follows: adding activated carbon to the base material, stirring and adsorbing the activated carbon for 4 hours, filtering the activated carbon to remove the activated carbon after the treatment is completed, and completing the decolorization treatment. The activated carbon is pretreated before being added to the base material. The pretreatment method of activated carbon is as follows: the activated carbon is dried and ground to a powder particle size of 100 μm to obtain activated carbon powder, the activated carbon powder and the treatment liquid are added to a mixer, the mixer is set to 300 r / min and stirred for 30 minutes, the stirred product is washed with deionized water, and then sent to a tubular furnace, the tubular furnace is set to a heating rate of 6°C / min, the temperature is raised to 320°C, and the temperature is kept for 40 minutes, water vapor is introduced into the tubular furnace during the treatment process to complete the pretreatment of the activated carbon, wherein the mass of the treatment liquid is 4 times the mass of the activated carbon powder, the treatment liquid is prepared by mixing hydrogen peroxide, nitric acid, disodium ethylenediaminetetraacetic acid and ammonia water, the mass ratio of hydrogen peroxide, nitric acid, disodium ethylenediaminetetraacetic acid and ammonia water is 1:3:0.05:0.3, the mass concentration of hydrogen peroxide is 4%, and the mass concentration of ammonia water is 22%; The temperature of the reduced pressure concentration treatment is 80°C, the vacuum degree is -0.1 MPa, and the treatment time is 40 min; S3: Preparation of finished product: adding ethanol to the concentrated base material for crystallization, followed by crystal growth, filtration, and drying to obtain carnosine; The method for preparing the finished product is as follows: ethanol is added dropwise to the concentrated base material and stirred, the temperature is set to 60°C during the addition, the addition of ethanol is stopped after crystals appear, and crystal growing is carried out, the remaining ethanol is added dropwise after the crystal growing is completed, and after the addition is completed, the temperature is set to 46°C, and the constant temperature stirring is carried out for 3 hours. The obtained product is filtered to obtain crystals, the crystals are rinsed with ethanol, and then the crystals are sent to an oven, and the oven is set at 90°C for drying for 40 minutes to obtain carnosine, wherein the mass of ethanol is 12 times the mass of carnosine powder, and the crystal growing time is 60 minutes.

[0023] Comparative Example 1: The difference between this comparative example and Example 1 is that in this comparative example, an equal amount of bamboo powder is used to replace the fiber material.

[0024] Comparative Example 2: The difference between this comparative example and Example 1 is that this comparative example does not contain fiber material.

[0025] Comparative Example 3: This comparative example differs from Example 1 in that: this comparative example does not contain a mixed liquid.

[0026] Comparative Example 4: This comparative example differs from Example 1 in that the activated carbon is not pretreated in this comparative example.

[0027] Performance test: Carnosine prepared in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 was subjected to performance test, and the obtained test data are recorded in the following table: It can be seen that the purity performance and yield performance of carnosine prepared in Comparative Examples 1, 2, 3, and 4 are all lower than those in Examples 1, 2, and 3. This shows that: by using a fiber material to prepare a base material in the crystallization preparation process of carnosine, after the fiber material is treated with Chinese parasol leaves as a raw material, 1-butyl-3-methylimidazole hexafluorophosphate can dissolve the cellulose in the Chinese parasol leaves, exposing more active sites, and the addition of polyethylene glycol can improve the uniformity of the dispersion of the fiber material. The surface of the microcrystalline cellulose in the fiber material can serve as a template to guide the carnosine molecules to arrange according to a specific lattice through the interfacial induction effect, thereby reducing its crystal defects, lowering the nucleation energy barrier, and accelerating the formation of crystal nuclei, thereby achieving the purpose of improving the purity and yield of the carnosine crystallization preparation. By pre-treating the activated carbon in the decolorization step, the activated carbon can be ground into fine powder to increase its specific surface area, exposing more micropores on its surface, thereby improving its adsorption capacity. The use of the treatment liquid can generate oxygen-containing functional groups on the surface of the activated carbon, thereby enhancing the adsorption capacity of pigment molecules. The introduction of water vapor can regulate the hydrophilic balance and enhance the adsorption performance of zwitterions, thereby making the adsorption treatment of impurities in the crystallization preparation of carnosine more thorough, and further improving the purity and yield of the carnosine crystallization preparation.

[0028] By comparing and analyzing the relevant data in the table, it can be seen that the carnosine prepared by the carnosine crystallization method of the present invention not only has good purity performance, but also has excellent yield performance. This shows that the carnosine crystallization method provided by the present invention has a broader market prospect and is more suitable for promotion.

[0029] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0030] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for crystallizing carnosine, characterized in that: The following steps are involved: S1: Preparation of a base material, wherein the raw materials of the base material include water, carnosine powder, histidine, β-alanine, and fiber material, wherein the mass percentage of each raw material is: 4-6% carnosine powder, 0.06-0.08% histidine, 0.1-0.3% β-alanine, 0.4-0.6% fiber material, and the balance is water. After mixing the raw materials, the base material is purified by a membrane system and electrodialysis to obtain the base material; S2: Pretreatment: the base material is decolorized and then concentrated under reduced pressure to obtain a concentrated base material; The temperature of the reduced pressure concentration treatment is 40-80°C, the vacuum degree is -0.1Mpa, and the treatment time is 30-40min; S3: Preparation of finished product: adding ethanol to the concentrated base material for crystallization, followed by crystal growth, filtration and drying to obtain carnosine.

2. The crystallization method of carnosine according to claim 1, wherein The fiber material is prepared by the following method: fresh sycamore leaves are selected, immersed in clean water for 2 to 4 hours, then drained and dried, and after drying, ground to a particle size of 2 to 10 μm to obtain a powder, the powder and sodium hydroxide solution are added to a water bath and mixed, stirred evenly, and then set to heat to 86 to 88° C. and react at a constant temperature for 1 to 3 hours, the obtained product is filtered, and the precipitate is taken and washed with deionized water to obtain a coarse material for standby use.

3. The crystallization method of carnosine according to claim 2, wherein The coarse material and the mixed liquid are added to a mixer, which is set at 120-160 r / min and stirred for 10-20 minutes. The product obtained by stirring is added to a ball mill, and the ball milling time is 6-10 minutes. The ball milling is performed 3-5 times with an interval of 2-4 minutes. The product obtained by ball milling is added to a centrifuge, and the centrifuge is set at 3000-5000 r / min and centrifuged for 4-6 minutes. The precipitate is taken from the product obtained by centrifugation, and the precipitate is sent to an oven, which is set at 40-50°C and dried for 3-6 hours. The obtained product is ground to obtain a fiber material with a grinding particle size of 2-10 μm.

4. The crystallization method of carnosine according to claim 3, wherein The mass ratio of the powder to the sodium hydroxide solution is 1: (6-8), the mass concentration of the sodium hydroxide solution is 3-5%, and the mass ratio of the coarse material to the mixed liquid is 1: (1.2-1.4).

5. The crystallization method of carnosine according to claim 3, wherein The mixed liquid is prepared by mixing 1-butyl-3-methylimidazolium hexafluorophosphate and polyethylene glycol, and the mass ratio of 1-butyl-3-methylimidazolium hexafluorophosphate to polyethylene glycol is 1:(0.1-0.2).

6. The crystallization method of carnosine according to claim 1, wherein The decolorization method is as follows: adding activated carbon to the base material, performing stirring and adsorption treatment for 2 to 4 hours, and after the treatment is completed, filtering to remove the activated carbon to complete the decolorization treatment, wherein the mass of the activated carbon is 4 to 6% of the mass of the base material, and the activated carbon is pretreated before being added to the base material.

7. The method for crystallizing carnosine according to claim 6, wherein The activated carbon pretreatment method comprises the following steps: drying and grinding the activated carbon to obtain activated carbon powder with a grinding particle size of 60 to 100 μm, adding the activated carbon powder and a treatment liquid into a mixer, setting the mixer at 200 to 300 r / min and stirring for 20 to 30 minutes, washing the stirred product with deionized water, and then feeding the product into a tubular furnace, setting the heating rate of the tubular furnace at 4 to 6°C / min, heating the temperature to 280 to 320°C, and keeping the temperature for 30 to 40 minutes. During the treatment process, water vapor is introduced into the tubular furnace to complete the pretreatment of the activated carbon, wherein the mass of the treatment liquid is 2 to 4 times the mass of the activated carbon powder.

8. The method for crystallizing carnosine according to claim 7, wherein The treatment liquid is prepared by mixing hydrogen peroxide, nitric acid, disodium ethylenediaminetetraacetate and ammonia water, wherein the mass ratio of hydrogen peroxide, nitric acid, disodium ethylenediaminetetraacetate and ammonia water is 1:(2-3):(0.03-0.05):(0.1-0.3), the mass concentration of hydrogen peroxide is 2-4%, and the mass concentration of ammonia water is 20-22%.

9. The method for crystallizing carnosine according to claim 1, wherein The method for preparing the finished product comprises the following steps: adding ethanol dropwise to the concentrated base material while maintaining stirring, setting the temperature at 40-60° C. during the addition, stopping the addition of ethanol after crystals appear, performing crystal growing, adding the remaining ethanol dropwise after the crystal growing, setting the temperature at 42-46° C. after the addition, performing constant temperature stirring for 1-3 hours, filtering the obtained product to obtain crystals, rinsing the crystals with ethanol, and then placing the crystals in an oven, setting the oven at 70-90° C. for drying for 20-40 minutes, thereby obtaining carnosine.

10. The method for crystallizing carnosine according to claim 9, wherein The mass of ethanol is 8 to 12 times the mass of carnosine powder, and the crystal growth treatment time is 40 to 60 minutes.

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