Ginger extract and refining method thereof

Abstract

The invention relates to the technical field of extract refining, and particularly discloses a ginger extract and a refining method thereof. The method for refining the ginger extract comprises the following steps: (1) dispersing and dissolving a ginger extract raw material by adopting low-carbon alcohol to obtain feed liquid I; the raw material of the fresh ginger extract is a fresh ginger extract obtained by extracting fresh ginger by adopting supercritical carbon dioxide; (2) adjusting the pH value of the feed liquid I to 12-13, and after full reaction, adjusting the pH value to 5-6 to obtain feed liquid II; (3) concentrating the feed liquid II until the concentration of the low-carbon alcohol is 15-45%, standing, and separating to obtain a lower-layer material; and (4) fully mixing the lower-layer material with low-carbon alcohol with the concentration of 15-45%, standing, separating and collecting a lower layer. The method provided by the invention can effectively remove pesticide residues in the raw materials of the ginger extract, and a safer product is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of extract refining, in particular to a ginger extract and a refining method thereof. Background Art

[0002] Ginger is the fresh rhizome of a perennial herbaceous plant of the Zingiberaceae family and the genus Zingiberaceae. Ginger is warm in nature, and its unique "gingerol" can stimulate the gastrointestinal mucosa, causing congestion in the gastrointestinal tract and enhancing digestion. It can effectively treat abdominal distension, abdominal pain, diarrhea, vomiting, etc. caused by eating too much cold food. After eating ginger, people will feel hot because it can dilate blood vessels, speed up blood circulation, and open the pores on the body, which can not only take away excess heat, but also take out germs and cold air in the body.

[0003] The main methods for extracting ginger extract are steam distillation, solvent extraction, ultrasonic method, supercritical carbon dioxide extraction and pressing method. At present, supercritical carbon dioxide extraction technology is relatively mature, and the extraction temperature is low during the supercritical carbon dioxide extraction process. The yield of ginger essential oil and gingerol in the extraction process is ideal, which is very suitable for large-scale ginger raw material processing and industrial production.

[0004] However, in order to maximize ginger production, excessive amounts of pesticides are usually used to fumigate the planting area before planting to prevent insect infestation and viral infection. Pesticides need to be sprayed intermittently during the planting process to prevent insects and ensure the healthy growth of ginger seedlings. A large amount of pesticides need to be sprayed during the storage process after harvesting for antibacterial and insect control. This leads to excessive pesticide residues in the ginger produced. When extracting through supercritical carbon dioxide extraction, some pesticide residues in the ginger raw material will migrate to the ginger extract product, and the types of pesticide residues are complex, the properties are diverse, and the dosage exceeds the standard. The main types of pesticide residues include organophosphorus pesticide residues, organochlorine pesticide residues, etc. Pesticide residues have become one of the main factors restricting the use of ginger extract in food.

[0005] At present, there are related preparation technologies for removing pesticide residues, including separation using supercritical carbon dioxide extraction technology, such as Chinese patent CN116474415A, which uses ginger essential oil as an entrainer to separate pesticide residues from ginger oleoresin, but its operation is complicated and the effect of removing pesticide residues still needs to be improved. Therefore, further research is needed on the removal of pesticide residues from ginger extracts. Summary of the invention

[0006] One of the objects of the present invention is to provide a method for purifying ginger extract with low pesticide residue and high yield.

[0007] The present invention provides a method for refining ginger extract, comprising: (1) using low-carbon alcohol to disperse and dissolve ginger extract raw material to obtain liquid 1; the ginger extract raw material is ginger extract obtained by extracting ginger with supercritical carbon dioxide; (2) adjusting the pH value of the feed solution 1 to 12-13, and after sufficient reaction, adjusting the pH value to 5-6 to obtain feed solution 2; (3) After concentrating the second feed liquid to a concentration of low-carbon alcohol of 15%-45%, the feed liquid is allowed to stand at 30-50°C to separate and obtain a lower layer material (oily resin); (4) The lower layer material is fully mixed with low-carbon alcohol having a concentration of 15%-45% at 30-50° C., allowed to stand, and the lower layer is collected.

[0008] The present invention has found that the ginger extract obtained by extracting ginger with supercritical carbon dioxide has serious pesticide residue problems and cannot meet the application requirements. Further, it has been found that when the ginger extract obtained by extracting ginger with supercritical carbon dioxide is first dissolved and dispersed, and then the pH value is adjusted to a specific alkaline condition for sufficient reaction, thiamethoxam and thiazophos can be effectively removed. After that, the pH value of the feed solution is adjusted to 5-6, and then the alcohol concentration in the feed solution is within a specific range, and it is purified and washed at a specific temperature, so that other pesticide residues can be further removed, and finally a ginger extract with low pesticide residues is obtained.

[0009] If the pH value is not within the range specified in the present invention when the feed liquid fully reacts under alkaline conditions, it is impossible to take into account both the full removal of pesticide residues and the high yield of gingerol in the product. If the concentration of the alcohol solution is too low or the temperature is too low during purification and washing, it is not conducive to the full removal of pesticide residues. If the concentration of the alcohol solution is too high or the temperature is too high, it will affect the yield of gingerol in the product. Under the purification and washing conditions specified in the present invention, it is beneficial to improve the yield of gingerol.

[0010] Compared with traditional pesticide residue removal methods, the method of the present invention has the advantages of being safer, greener, low in production cost, and suitable for industrial large-scale production. The gingerol in the obtained ginger extract has high purity and can be used at high value.

[0011] The ginger extract raw material of the present invention can be produced by a supercritical carbon dioxide extraction method known in the art. For example, the specific production method includes: the dried ginger slices are crushed and put into a supercritical carbon dioxide extraction kettle, the pressure of the extraction kettle is increased to 25-30MPa, the temperature is maintained at 35-55°C, the carbon dioxide flow rate is 5-10kg / h per kilogram of dried ginger raw material, the extraction time is 3-5h, the pressure of the separation kettle is 6-10MPa, and the temperature of the separation kettle is 30-50°C.

[0012] The pesticide residues include one or more of organophosphorus pesticides, organochlorine pesticides and phenylamide pesticides. Organophosphorus pesticides include thiamethoxam, imidacloprid, thiamethoxam, clothianidin, etc. Organochlorine pesticides include chlorpyrifos, etc. Phenylamide pesticides include metalaxyl, etc.

[0013] In the present invention, when adjusting the pH value, an acid-base reagent such as sodium hydroxide, potassium hydroxide, hydrochloric acid, phosphoric acid or nitric acid can be used, and sodium hydroxide and hydrochloric acid are preferably used.

[0014] In step (1) of the method of the present invention, the low-carbon alcohol is one or more of ethanol and methanol; the concentration of the low-carbon alcohol is greater than or equal to 55%, preferably 55%-95%.

[0015] More preferably, the low-carbon alcohol is ethanol; and the concentration of the low-carbon alcohol is 65%.

[0016] The present invention preferably uses an aqueous ethanol solution to facilitate industrial recycling.

[0017] In the method of the present invention, the mass volume ratio of the ginger extract raw material and the low-carbon alcohol is 1: (3-7) g / mL; and / or, in step (1), the dispersing and dissolving is carried out at 25-50°C.

[0018] Preferably, the mass volume ratio of the ginger extract raw material and the low-carbon alcohol is 1:4 g / mL; and the dispersion and dissolution are carried out at 30-50° C. (preferably, 35-45° C.).

[0019] In step (4) of the method of the present invention, the mass volume ratio of the lower layer material to the low-carbon alcohol is 1:(1-3) g / mL.

[0020] In step (2) of the method of the present invention, the full reaction is carried out at 25-55° C. and the reaction time is 1-3 hours.

[0021] Preferably, in step (2), the reaction is fully carried out at 30-50° C. (more preferably, 35-45° C.) The reaction under the conditions of the present invention can ensure that the reaction is fully carried out and help avoid the loss of gingerol yield.

[0022] The method of the present invention further comprises a step of removing residual solvent after step (4).

[0023] The conditions for removing the residual solvent may be: water bath temperature 55°C-70°C, vacuum degree -0.06MPa to -0.1Mpa.

[0024] In step (3) of the method of the present invention, the concentration conditions are: water bath temperature 55°C-70°C, vacuum degree -0.06MPa to -0.1MPa.

[0025] In the method of the present invention, step (4) is preferably repeated 2-5 times, more preferably repeated 2-3 times, so as to take into account both the effect of removing pesticide residues and production efficiency.

[0026] The present invention also provides a ginger extract, which is prepared by the above method.

[0027] The ginger extract obtained by the method of the present invention has low pesticide residues, and pesticide residues such as thiamethoxam, thiazofos, chlorpyrifos, and metalaxyl are not detected (the detection limit is 0.1 ppm).

[0028] The beneficial effects of the present invention are at least: The invention provides a method for removing pesticide residues in ginger extract, which solves the problem of excessive pesticide residues in ginger extract products. The process of the invention is simple to operate and low in cost, can be effectively applied to large-scale production, can completely separate gingerol and pesticide residues, and prepare clean and safe ginger extract products. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention will be described in detail below in conjunction with the examples. It should be understood that the following examples are provided only for the purpose of illustration and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0030] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples are commercially available or prepared according to conventional methods in the art unless otherwise specified.

[0031] The raw material used in the embodiment of the present invention is a ginger extract produced by supercritical carbon dioxide extraction for the purpose of extracting gingerol. The specific production method is: the dried ginger slices are crushed and put into a supercritical carbon dioxide extraction kettle, the pressure of the extraction kettle is increased to 28MPa, the temperature is maintained at 45°C, the carbon dioxide flow rate is 8kg / h per kilogram of dried ginger raw material, the extraction time is 4h, the separation kettle pressure is 8MPa, and the separation kettle temperature is 40°C.

[0032] The content of gingerols (including 6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol, and 8-shogaol) in the final ginger extract was 41.35%, with 2.13 ppm of chlorpyrifos, 3.73 ppm of thiamethoxam, 2.46 ppm of imidacloprid, 1.72 ppm of thiamethoxam, and 6.25 ppm of metalaxyl.

[0033] In the present invention, chlorpyrifos, thiamethoxam and metalaxyl are detected with reference to GB 23200.113, thiamethoxam is detected with reference to GB23200.9, and imidacloprid is detected with reference to GB / T 20769.

[0034] Example 1 This embodiment provides a method for removing pesticide residues in ginger extract, and the specific steps are as follows: 1. Weigh 100 kg of ginger extract raw material, add 4 times the volume (L) of the extract weight of ethanol solution (concentration 65%), stir at 40 ° C for 0.5 h to fully mix to obtain liquid 1; 2. Add sodium hydroxide reagent to the feed solution 1 to adjust the pH to 12.5, stir and react at 40°C for 2 hours, then add hydrochloric acid dilution to the feed solution to adjust the pH to 5.5 to obtain feed solution 2; 3. Concentrate the feed liquid 2 at a water bath temperature of 65°C and a vacuum degree of -0.08MPa until the ethanol concentration in the feed liquid is 30%, then stand at 40°C for 0.5h and collect the lower layer; 4. Add 30% ethanol solution (material-liquid ratio 1:2 kg / L) to the lower layer material again, stir at 40℃ for 1h, let stand for 0.5h, and collect the lower layer material. The ethanol solvent washing was repeated according to the above operation for a total of 3 times, and the upper ethanol solutions after each washing were combined. The combined upper ethanol solution and the lower material were respectively desolventized (the water bath temperature was 65°C and the vacuum degree was -0.08MPa). After the lower layer was concentrated, 86.69kg of ginger oleoresin without pesticide residues was obtained, with a gingerol content of 39.87% and a content yield of 83.59%. Chlorpyrifos, thiamethoxam, imidacloprid, thiamethoxam and metalaxyl were not detected (detection limit 0.1ppm). After the ethanol solution was concentrated, 12.43kg of common ginger oleoresin was obtained, with a gingerol content of 41.43% and a content yield of 12.45%. Chlorpyrifos was 2.81ppm, imidacloprid was 3.47ppm, metalaxyl was 10.84ppm, thiamethoxam and thiamethoxam were not detected (detection limit 0.1ppm), and the total gingerol content yield was 96.04%.

[0035] Example 2 This embodiment provides a method for removing pesticide residues in ginger extract, and the specific steps are as follows: 1. Weigh 100 kg of ginger extract raw material, add 7 times the volume (L) of the extract weight of ethanol solution (concentration 55%), stir at 50 ° C for 0.5 h to fully mix to obtain liquid 1; 2. Add sodium hydroxide reagent to the feed solution 1 to adjust the pH to 12.0, stir and react at 55°C for 3 hours, then add hydrochloric acid dilution to the feed solution to adjust the pH to 5 to obtain feed solution 2; 3. Concentrate the feed liquid 2 at a water bath temperature of 70°C and a vacuum degree of -0.06MPa until the concentration of ethanol in the feed liquid is 15%, then stand at 50°C for 0.5h and collect the lower layer; 4. Add 15% ethanol solution (material-liquid ratio 1:3 kg / L) to the lower layer material again, stir at 50℃ for 1h, let stand for 0.5h, and collect the lower layer material. The ethanol solvent washing was repeated according to the above operation for a total of 5 times, and the upper ethanol solutions after each washing were combined. The combined upper ethanol solution and the lower material were respectively desolventized (the water bath temperature was 70°C and the vacuum degree was -0.06MPa). After the lower layer was concentrated, 86.82kg of ginger oleoresin without pesticide residues was obtained, with a gingerol content of 40.03% and a content yield of 84.05%. Chlorpyrifos, thiamethoxam, imidacloprid, thiamethoxam and metalaxyl were not detected (detection limit 0.1ppm). After the ethanol solution was concentrated, 12.14kg of common ginger oleoresin was obtained, with a gingerol content of 41.12% and a content yield of 12.07%. Chlorpyrifos was 2.45ppm, imidacloprid was 3.45ppm, metalaxyl was 9.74ppm, thiamethoxam and thiamethoxam were not detected (detection limit 0.1ppm), and the total gingerol content yield was 96.12%.

[0036] Example 3 This embodiment provides a method for removing pesticide residues in ginger extract, and the specific steps are as follows: 1. Weigh 100 kg of ginger extract raw material, add 3 times the volume (L) of the extract weight of ethanol solution (concentration 95%), stir at 25 ° C for 0.5 h to fully mix to obtain liquid 1; 2. Add sodium hydroxide reagent to the feed solution 1 to adjust the pH to 13.0, stir and react at 25°C for 1 hour, then add hydrochloric acid dilution to the feed solution to adjust the pH to 6 to obtain feed solution 2; 3. Concentrate the feed liquid 2 at a water bath temperature of 55°C and a vacuum degree of -0.1MPa until the ethanol concentration in the feed liquid is 45%, then let it stand at 30°C for 0.5h and collect the lower layer; 4. Add 45% ethanol solution (material-liquid ratio 1:1 kg / L) to the lower layer material again, stir at 30℃ for 1h, let stand for 0.5h, and collect the lower layer material. The ethanol solvent washing was repeated according to the above operation for 2 times in total, and the upper ethanol solutions after each washing were combined. The combined upper ethanol solution and the lower material were respectively desolventized (water bath temperature was 55°C, vacuum degree was -0.1MPa), and the lower layer was concentrated to obtain 85.46kg of ginger oleoresin without pesticide residues, with a gingerol content of 39.68% and a content yield of 82.01%. Chlorpyrifos, thiamethoxam, imidacloprid, thiamethoxam and metalaxyl were not detected (detection limit 0.1ppm). After the ethanol solution was concentrated, 12.76kg of common ginger oleoresin was obtained, with a gingerol content of 42.35%, a content yield of 13.07%, chlorpyrifos 3.21ppm, imidacloprid 3.97ppm, metalaxyl 11.23ppm, thiamethoxam and thiamethoxam were not detected (detection limit 0.1ppm), and the total gingerol content yield was 95.08%.

[0037] Comparative Example 1 This comparative example provides a method for removing pesticide residues from ginger extract, and the specific method is basically the same as that in Example 1, except that in step 2, sodium hydroxide reagent is added to the feed solution 1 to adjust the pH to 14, and the remaining steps are the same as those in Example 1. After the final lower layer is concentrated, 86.61 kg of ginger oleoresin with pesticide residues removed is obtained, with a gingerol content of 23.17%, a content yield of 48.53%, and no chlorpyrifos, thiamethoxam, imidacloprid, thiamethoxam, and metalaxyl are detected (detection limit 0.1 ppm). After the ethanol solution is concentrated, 12.46 kg of ordinary ginger oleoresin is obtained, with a gingerol content of 24.15%, chlorpyrifos 0.41 ppm, imidacloprid 0.35 ppm, metalaxyl 0.48 ppm, thiamethoxam and thiamethoxam are not detected (detection limit 0.1 ppm), and a content yield of 7.28%. The total content yield of gingerol is 55.81%.

[0038] Comparative Example 2 This comparative example provides a method for removing pesticide residues in ginger extract, and the specific method is basically the same as that in Example 1, except that in step 2, sodium hydroxide reagent is added to the feed solution one to adjust pH=11. After the final lower layer is concentrated, 86.72kg of ginger oleoresin with pesticide residues removed is obtained, with a gingerol content of 40.56%, a content yield of 85.06%, 1.31ppm of chlorpyrifos, 0.27ppm of thiamethoxam, 0.73ppm of imidacloprid, 0.11ppm of thiamethoxam, and 1.97ppm of metalaxyl. After the ethanol solution is concentrated, 12.38kg of common ginger oleoresin is obtained, with a gingerol content of 41.96%, a content yield of 12.56%, 5.42ppm of chlorpyrifos, 1.17ppm of thiamethoxam, 4.38ppm of imidacloprid, 0.89ppm of thiamethoxam, and 28.36ppm of metalaxyl. The total content yield of gingerol is 97.63%.

[0039] Comparative Example 3 This comparative example provides a method for removing pesticide residues in ginger extract, and the specific method is basically the same as Example 1, except that the feed liquid 2 obtained in step 2 is directly concentrated to remove pesticide residues, and the ethanol separation and washing steps in steps 3 and 4 are not performed. Finally, 99.87 kg of ginger oleoresin without pesticide residues was obtained, with a gingerol content of 39.92%, a content yield of 96.42%, 0.16 ppm of chlorpyrifos, no detection of thiamethoxam, 0.39 ppm of imidacloprid, no detection of thiathion, and 0.48 ppm of metalaxyl.

[0040] Comparative Example 4 This comparative example provides a method for removing pesticide residues from ginger extract. The specific method is basically the same as that in Example 1, except that steps 1, 2, and 3 are not performed, and the ginger extract raw material is directly added to 30% ethanol for washing 4 times (solid-liquid ratio 1: 2 kg / L). After the final lower layer is concentrated, 86.43 kg of ginger oleoresin with pesticide residues removed is obtained, with a gingerol content of 40.97%, a content yield of 85.64%, 1.43 ppm of chlorpyrifos, 0.75 ppm of thiamethoxam, 1.33 ppm of imidacloprid, 0.42 ppm of thiamethoxam, and 2.52 ppm of metalaxyl. After the ethanol solution is concentrated, 12.53 kg of ordinary ginger oleoresin is obtained, with a gingerol content of 42.76%, a content yield of 12.96%, 7.08 ppm of chlorpyrifos, 24.62 ppm of thiamethoxam, 10.65 ppm of imidacloprid, 10.87 ppm of thiamethoxam, and 31.37 ppm of metalaxyl. The total content yield of gingerol is 98.59%.

[0041] Comparative Example 5 This comparative example provides a method for removing pesticide residues from ginger extract, and the specific method is basically the same as that in Example 1, except that in step 3, the feed solution 2 is concentrated to an ethanol content of <1%, and the lower layer ginger oleoresin is washed 4 times with 30% ethanol, and the steps not described in detail are the same as those in Example 1. After the lower layer is finally concentrated, 86.53 kg of ginger oleoresin with pesticide residues removed is obtained, with a gingerol content of 39.85%, a content yield of 83.39%, 0.12 ppm of chlorpyrifos, no detection of thiamethoxam, 0.11 ppm of imidacloprid, no detection of thiamethoxam, and 0.15 ppm of metalaxyl. After the ethanol solution is concentrated, 12.28 kg of ordinary ginger oleoresin is obtained, with a gingerol content of 41.41%, a content yield of 12.30%, 1.74 ppm of chlorpyrifos, 2.84 ppm of imidacloprid, 9.97 ppm of metalaxyl, no detection of thiamethoxam and thiamethoxam (detection limit 0.1 ppm), and a total gingerol content yield of 95.69%.

[0042] Comparative Example 6 This comparative example provides a method for removing pesticide residues in ginger extract. The specific method is basically the same as that in Example 1, except that in step 3, the feed liquid 2 is concentrated to a concentration of 10% ethanol in the feed liquid, and the mixture is allowed to stand at 40° C. for 0.5 h, and the lower layer is collected. In step 4, a 10% ethanol solution is added to the lower layer material again for washing, and the remaining steps are the same as those in Example 1. After the final lower layer was concentrated, 93.24 kg of pesticide-free ginger oleoresin was obtained, with a gingerol content of 39.74%, a content yield of 89.61%, 0.17 ppm of chlorpyrifos, no detection of thiamethoxam, 0.28 ppm of imidacloprid, no detection of thiamethoxam, and 0.21 ppm of metalaxyl. After the ethanol solution was concentrated, 6.45 kg of ordinary ginger oleoresin was obtained, with a gingerol content of 39.85%, a content yield of 6.22%, 1.32 ppm of chlorpyrifos, 1.45 ppm of imidacloprid, 3.27 ppm of metalaxyl, no detection of thiamethoxam and thiamethoxam (detection limit 0.1 ppm), and a total gingerol content yield of 95.83%.

[0043] Comparative Example 7 This comparative example provides a method for removing pesticide residues in ginger extract. The specific method is basically the same as that in Example 1, except that in step 3, the feed liquid 2 is concentrated to a concentration of ethanol in the feed liquid of 50%, and the mixture is allowed to stand at 40° C. for 0.5 h, and the lower layer is collected. In step 4, a 50% ethanol solution is added to the lower layer material again for washing, and the remaining steps are the same as those in Example 1. Finally, after the lower layer was concentrated, 57.32 kg of pesticide-free ginger oleoresin was obtained, with a gingerol content of 31.54% and a content yield of 43.72%. Chlorpyrifos, thiamethoxam, imidacloprid, thiamethoxam and metalaxyl were not detected. After the ethanol solution was concentrated, 42.45 kg of ordinary ginger oleoresin was obtained, with a gingerol content of 51.03% and a content yield of 52.39%. Chlorpyrifos 0.89 ppm, imidacloprid 0.73 ppm, metalaxyl 2.51 ppm, thiamethoxam and thiamethoxam were not detected (detection limit 0.1 ppm), and the total gingerol content yield was 96.11%.

[0044] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A method for refining ginger extract, characterized in that, include: (1) using low-carbon alcohol to disperse and dissolve ginger extract raw material to obtain liquid 1; the ginger extract raw material is ginger extract obtained by extracting ginger with supercritical carbon dioxide; (2) adjusting the pH value of the feed solution 1 to 12-13, and after sufficient reaction, adjusting the pH value to 5-6 to obtain feed solution 2; (3) After concentrating the second feed liquid to a concentration of low-carbon alcohol of 15%-45%, the feed liquid is allowed to stand at 30-50° C., and the lower layer material is separated; (4) The lower layer material is fully mixed with low-carbon alcohol having a concentration of 15%-45% at 30-50° C., allowed to stand, and the lower layer is collected.

2. The method according to claim 1, characterized in that In step (1), the low-carbon alcohol is one or more of ethanol and methanol; the concentration of the low-carbon alcohol is greater than or equal to 55%, preferably 65%-85%.

3. The method according to claim 2, characterized in that In step (1), the low-carbon alcohol is ethanol; the concentration of the low-carbon alcohol is 65%.

4. The method according to any one of claims 1 to 3, characterized in that: The mass volume ratio of the ginger extract raw material and the low-carbon alcohol is 1: (3-7) g / mL; and / or, in step (1), the dispersing and dissolving is carried out at 25-50°C; Preferably, the mass volume ratio of the ginger extract raw material and the low-carbon alcohol is 1:4 g / mL; and the dispersion and dissolution are carried out at 30-50°C.

5. The method according to any one of claims 1 to 4, characterized in that: In step (4), the mass volume ratio of the lower layer material to the low-carbon alcohol is 1:(1-3) g / mL.

6. The method according to any one of claims 1 to 5, characterized in that: In step (2), the reaction is fully carried out at 25-55°C, preferably 30-50°C, and the reaction time is 1-3h.

7. The method according to any one of claims 1 to 6, characterized in that: After step (4), the method further includes a step of removing the residual solvent.

8. The method according to any one of claims 1 to 7, characterized in that: In step (3), the concentration conditions are: water bath temperature 55°C-70°C, vacuum degree -0.06MPa to -0.1MPa.

9. The method according to any one of claims 1 to 8, characterized in that: Repeat step (4) 2-5 times.

10. A ginger extract, characterized in that The method is prepared by any one of claims 1 to 9.