Preparation method and application of a lime fruit extract

Abstract

The present invention belongs to the technical field of extracts, and discloses a preparation method and application of an extract of Citrus aurantium fruit. The preparation method of the present invention is as follows: vacuum freeze-dry the pericarp of Citrus aurantium, crush and sieve it to obtain Citrus aurantium peel powder; take the Citrus aurantium peel powder, add an extraction solvent, mix evenly, and perform ultrasonic-assisted extraction to obtain a crude extract; centrifuge the crude extract to obtain a supernatant; filter the supernatant by suction to obtain a filtrate; subject the filtrate to column chromatography treatment, elute to obtain an eluate; concentrate the eluate under reduced pressure, heat, decolorize, filter, and then vacuum freeze-dry to obtain an extract of Citrus aurantium fruit. The preparation method of the present invention uses an ionic liquid as an extraction solvent, which does not require volatile organic solvents, has good biocompatibility, and the ionic liquid can be reused after simple treatment. The extract of Citrus aurantium fruit prepared by the present invention has a significant soothing effect and is widely applicable to the preparation of soothing cosmetics.

Description

Technical Field

[0001] The present invention relates to the technical field of extracts, and specifically relates to a preparation method and application of an extract of Citrus aurantium fruit. Background Art

[0002] Citrus aurantium (Citrus reticulata Blanco), a plant under the Rutaceae family, the pericarp residue of Citrus aurantium has high medicinal value. Hesperidin is one of the main components of Citrus aurantium flavonoids. The full name of hesperidin is hesperetin-7-O-neohesperidoside, which has high biological activity, good antioxidant effect, and inhibitory effect on the mutagenicity of heterocyclic amines, 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid and N-methyl-N-nitro-N-nitrosoguanidine; it can inhibit the carcinogenic effects of nitrosamines, aflatoxin and other carcinogens, and has a certain preventive effect on tumors such as breast cancer and lung cancer; it has a preventive and therapeutic effect on gastric ulcers; it has an inhibitory effect on Staphylococcus aureus, Salmonella, etc.; it has an antagonistic effect on certain poisons; in addition, it also has functions such as anti-inflammatory, lipid-lowering, cholesterol-lowering, spasmolysis, and analgesia.

[0003] In the prior art, Chinese patent document CN 106866758 A discloses a process for extracting hesperidin from tangerine peel, including the following steps: pulverization - heat preservation and pressure maintenance - cooling - alkali solution and enzyme treatment - stirring and standing - neutralization - redissolution - resin adsorption - elution - evaporation and drying. However, a large amount of organic solvents are required during the elution of this process, the amount of sewage is large, the process is complex, it takes a long time, and steam must be used, resulting in high energy consumption. Chinese patent document CN 111362993 A discloses a new process method for extracting hesperidin, including the following steps: pulverizing the Fructus Aurantii Immaturus raw material, and the pulverization particle size is 40 - 60 mesh; pretreating the pulverized raw material with a sodium citrate solution for 3 - 5 hours, and the concentration of the sodium citrate solution is controlled at 1% - 5%; after treatment, filter, add the filter residue to an alkaline extraction solution, control the concentration at 0.5% - 2.5%, and the extraction time is 3 - 6 hours; first, perform rough filtration on the alkaline extraction solution, then perform fine filtration, and transfer the filtrate to a stirring tank; during the stirring of the extraction filtrate, slowly add acid to adjust the pH, and the pH is controlled at 4.5 - 6.5, and wait for crystallization for 6 - 12 hours; the crystallization solution passes through a plate and frame, and the filter cake is rinsed with purified water until it is colorless, then the filter cake is dried, and transferred to a drying oven for drying, and the drying temperature is 70°C - 105°C. However, this method uses sodium citrate for impurity removal. Since alkaline solution extraction is used for hesperidin extraction, hesperidin and impurities such as naringin and isonaringin will be extracted simultaneously. Theoretically, sodium citrate cannot remove impurities similar to hesperidin substances, but can only remove impurities such as colloids. The obtained product is unqualified, with low purity and yield, and this method has a long operation time and low production efficiency.

[0004] At present, the commonly used extraction methods for lime fruit extracts are maceration method and ethanol solvent reflux method. However, these methods have disadvantages such as large solvent consumption, high toxicity and side effects, low yield of finished products, and long time, which are not conducive to industrialization. Different extraction methods will not only directly affect the extraction rate, purity and production cost of lime fruit extracts, but also have a significant impact on the functions and qualities of downstream products. Therefore, it is urgent to establish a safe, green and efficient extraction method for lime fruit extracts. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a preparation method and application of lime fruit extracts.

[0006] To achieve the above purpose, the technical solutions adopted by the present invention are as follows:

[0007] In the first aspect, the present invention provides a preparation method of lime fruit extracts, including the following steps:

[0008] (1) Vacuum freeze-dry the lime fruit peel, crush and sieve it to obtain lime peel powder;

[0009] (2) Take the lime peel powder, add an extraction solvent, mix evenly, and perform ultrasonic-assisted extraction to obtain a crude extract; the extraction solvent is a mixed aqueous solution of ionic liquid, ammonia water and basic alumina; the mass ratio of ionic liquid: ammonia water: basic alumina is 4-6:1:0.5;

[0010] (3) Centrifuge the crude extract to obtain a supernatant; filter the supernatant by suction to obtain a filtrate;

[0011] (4) Subject the filtrate to column chromatography treatment and elute to obtain an eluate;

[0012] (5) Concentrate the eluate under reduced pressure, heat, decolorize, filter, and then vacuum freeze-dry to obtain lime fruit extracts.

[0013] The preparation method of the present invention is based on the principle of "like dissolves like". After the ionic liquid is dissolved in water to form a homogeneous solution, basic alumina and ammonia water are added. Since the extract of bitter orange fruit has phenolic hydroxyl groups and is easily soluble in dilute alkali solutions, ammonia water provides an alkaline condition, but strong alkali solutions cannot be used as they will destroy its parent nucleus. Basic alumina can, on the one hand, provide an alkaline environment, and on the other hand, play a role in adsorbing pigment components, reducing the pressure for subsequent elution and impurity removal, and further improving the yield and content of the extract. Among them, the ionic liquid composed of organic cations and inorganic anions has the characteristics of low vapor pressure, high thermal stability and chemical stability, and high potential recovery rate. Using ionic liquid as the extraction solvent does not require volatile organic solvents, has good biocompatibility, and the ionic liquid can be reused after simple treatment. The ultrasonic-assisted extraction method is adopted, and ultrasonic cavitation can accelerate the entry of hesperidin in the plant into the solvent, increase the yield of hesperidin in the finished product, reduce the amount of extraction solvent used, and is more environmentally friendly.

[0014] As a preferred embodiment of the preparation method of the present invention, in step (1), the freeze-drying time is 48 - 60 h; the mesh number of sieving is 40 - 80 mesh.

[0015] As a preferred embodiment of the preparation method of the present invention, in step (2), the material-liquid ratio of the bitter orange peel powder to the extraction solvent is 1 g / 15 - 35 mL.

[0016] As a preferred embodiment of the preparation method of the present invention, in step (2), the extraction temperature is 25°C - 28°C, and the time is 8 - 15 min; the mass fraction of the extraction solvent is 40% - 70%.

[0017] As a preferred embodiment of the preparation method of the present invention, in step (2), the ionic liquid is a basic functional ionic liquid, a quaternary ammonium ionic liquid or a quaternary phosphonium ionic liquid that can be dissolved in water.

[0018] As a preferred embodiment of the preparation method of the present invention, the basic functional ionic liquid is 1-butyl-3-methylimidazolium hydroxide; the quaternary ammonium ionic liquid is at least one of tributylhexylammonium bromide, tetramethylammonium tetrafluoroborate, and tributylhexylammonium tetrafluoroborate; the quaternary phosphonium ionic liquid is hexyltributylphosphonium bromide and / or tetrabutylphosphonium bromide.

[0019] As a preferred embodiment of the preparation method of the present invention, in step (3), the centrifugation speed is 6000 - 10000 rpm.

[0020] As a preferred embodiment of the preparation method of the present invention, in step (4), the column chromatography uses D101 macroporous adsorption resin; the elution is carried out with ethanol having a volume concentration of 48% - 52%.

[0021] As a preferred embodiment of the preparation method of the present invention, in step (5), the heating temperature is 80°C to 90°C; the decolorization is carried out using activated carbon; the pressure of the vacuum freeze-drying is -0.1 MPa, the temperature is -60 to -50°C, pre-freezing for 6 to 10 h, and drying until the water content of the bitter orange fruit extract < 1%.

[0022] In the second aspect, the present invention applies the bitter orange fruit extract prepared by the above-mentioned preparation method to cosmetics with a soothing effect.

[0023] Hesperidin, a flavonoid substance in the bitter orange fruit extract prepared by the preparation method of the present invention, is an active ingredient in Citrus reticulata Blanco cv. Tomentosa with a relatively strong ability to scavenge 1,1-diphenyl-2-picrylhydrazy (DPPH) free radicals. Inflammatory response plays a key role in host defense. When stimulated by pathogen invasion or endotoxin exposure, etc., it can activate the immune system to help the human body function return to normal. However, when there are too many inflammatory factors in the body, it will disrupt the immune system and cause damage to the body, thus triggering inflammation. The flavonoid hesperidin in the bitter orange fruit extract has a good therapeutic effect on inflammation, mainly playing a soothing effect by regulating cellular inflammatory molecules, affecting mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) inflammation-related signaling pathways, etc.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] According to the principle of like dissolves like in the preparation method of the present invention, after the ionic liquid is dissolved in water to form a homogeneous solution, basic alumina and ammonia water are added. Since the bitter orange fruit extract has phenolic hydroxyl groups and is easily soluble in dilute alkali solutions, ammonia water provides an alkaline condition, but strong alkali solutions cannot be used as they will destroy its parent nucleus; basic alumina can not only provide an alkaline environment but also play a role in adsorbing pigment components, reducing the pressure for subsequent elution and impurity removal, and further improving the finished product yield and content of the extract. Among them, the ionic liquid composed of organic cations and inorganic anions has the characteristics of low vapor pressure, high thermal stability and chemical stability, and high potential recovery rate. Using ionic liquid as the extraction solvent does not require volatile organic solvents, has good biocompatibility, and the ionic liquid can be reused after simple treatment; adopting the ultrasonic-assisted extraction method, ultrasonic cavitation can accelerate the entry of hesperidin in the bitter orange into the solvent, increase the finished product yield of hesperidin in the bitter orange, reduce the amount of extraction solvent used, and is more environmentally friendly. The bitter orange fruit extract prepared by the present invention has a significant soothing effect and is widely applicable to the preparation of soothing cosmetics. Description of the Drawings

[0026] Figure 1 For the soothing typical diagram, the red line in the figure represents the fast movement distance, the green line represents the medium-speed movement distance, and the black line represents the slow movement distance;

[0027] Figure 2 For the bar chart of the total movement distance, compared with the model control group, ***p < 0.001. Specific implementation manners

[0028] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] Unless otherwise specified, the test methods used in the examples are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0030] Example 1: A preparation method of lime fruit extract

[0031] The preparation method includes the following steps:

[0032] (1) Vacuum freeze-dry the lime peel for 48 - 60 h, crush the dried peel and pass it through a 40 - 80 mesh sieve to obtain lime peel powder, and place it in a dry and cool place for later use;

[0033] (2) Weigh the lime peel powder and the extraction solvent, mix them evenly and then carry out ultrasonic-assisted extraction. During the ultrasonic process, control the temperature with a constant temperature water of 25°C - 28°C, and the extraction time is 8 - 15 min to obtain a crude extract;

[0034] Among them, the extraction solvent is a mixed aqueous solution of ionic liquid, ammonia water and basic alumina; the mass ratio of ionic liquid: ammonia water: basic alumina is 4 - 6:1:0.5; the ionic liquid is a water-soluble basic functional ionic liquid, quaternary ammonium ionic liquid or quaternary phosphonium ionic liquid; the basic functional ionic liquid is 1-butyl-3-methylimidazolium hydroxide; the quaternary ammonium ionic liquid is tributylhexylammonium bromide, tetramethylammonium tetrafluoroborate or tributylhexylammonium tetrafluoroborate; the quaternary phosphonium ionic liquid is hexyltributylphosphonium bromide or tetrabutylphosphonium bromide; the material-liquid ratio of the lime peel powder and the extraction solvent is 1 g / 15 - 35 mL; the mass fraction of the extraction solvent is 40% - 70%;

[0035] (3) Centrifuge the crude extract at 6000 - 10000 rpm and retain the upper clear liquid; filter the upper clear liquid with a filter membrane to obtain a filtrate;

[0036] (4) After subjecting the filtrate to column chromatography and elution, an eluate is obtained;

[0037] Among them, D101 macroporous adsorption resin is used for column chromatography of the filtrate, and ethanol with a volume concentration of 48% - 52% is added for elution;

[0038] (5) The eluates are combined, concentrated under reduced pressure until the alcohol smell disappears, heated to 80°C - 90°C in a water bath, activated carbon is added for decolorization, filtered while hot, and then vacuum freeze-dried to obtain the extract of lime fruit;

[0039] Among them, the pressure of the vacuum freeze-drying is -0.1 MPa, the temperature is -60°C to -50°C, pre-frozen for 6 - 10 h, and dried to make the water content of the extract of lime fruit < 1%.

[0040] Example 2: A preparation method of the extract of lime fruit

[0041] This preparation method includes the following steps:

[0042] (1) The lime fruit peel is vacuum freeze-dried for 48 h, the dried peel is crushed and sieved through a 50-mesh sieve to obtain lime peel powder, which is placed in a dry and cool place for later use;

[0043] (2) Weigh the lime peel powder and the extraction solvent, mix them evenly, and perform ultrasonic-assisted extraction while maintaining the temperature. During the ultrasonic process, the temperature is controlled with a constant-temperature water bath at 25°C, and the extraction time is 10 min to obtain a crude extract;

[0044] Among them, the extraction solvent is a mixed solution of ionic liquid, ammonia water, and basic alumina; the ratio of ionic liquid: ammonia water: basic alumina is 4:1:0.5; the ionic liquid is the quaternary ammonium type ionic liquid tributylhexylammonium bromide that can dissolve in water; the material-liquid ratio of the lime peel powder and the extraction solvent is 1 g / 25 mL; the mass fraction of the extraction solvent is 60%;

[0045] (3) The crude extract is centrifuged at 6000 rpm, and the upper clear liquid is retained; the upper clear liquid is filtered with a filter membrane to obtain a filtrate;

[0046] (4) After subjecting the filtrate to column chromatography and elution, an eluate is obtained;

[0047] Among them, D101 macroporous adsorption resin is used for column chromatography of the filtrate, and ethanol with a volume concentration of 50% is added for elution;

[0048] (5) The eluates are combined, concentrated under reduced pressure until the alcohol smell disappears, heated to 80°C in a water bath, activated carbon is added for decolorization, filtered while hot, and then vacuum freeze-dried to obtain the extract of lime fruit;

[0049] Among them, the pressure of the vacuum freeze-drying is -0.1 MPa, the temperature is -55 °C, pre-freezing is carried out for 8 h, and then drying is carried out to make the water content of the lime fruit extract < 1%.

[0050] Example 3: A preparation method of lime fruit extract

[0051] The difference between this preparation method and Example 2 lies in that: in step (2), the ratio of ionic liquid: ammonia water: basic alumina is 6:1:0.5.

[0052] Example 4: A preparation method of lime fruit extract

[0053] The difference between this preparation method and Example 3 lies in that: in step (2), the ionic liquid is the water-soluble quaternary phosphonium ionic liquid hexyltributylphosphonium bromide.

[0054] Example 5: A preparation method of lime fruit extract

[0055] The difference between this preparation method and Example 3 lies in that: in step (2), the ionic liquid is the water-soluble basic functional ionic liquid 1-butyl-3-methylimidazolium hydroxide.

[0056] Comparative Example 1: A preparation method of lime fruit extract

[0057] The difference between this preparation method and Example 2 lies in that: in step (2), the extraction solvent is only the ionic liquid, and the ionic liquid is the water-soluble quaternary amine ionic liquid tributylhexylammonium bromide.

[0058] Comparative Example 2: A preparation method of lime fruit extract

[0059] The difference between this preparation method and Example 2 lies in that: in step (2), the extraction solvent is only the ionic liquid and ammonia water, and the ratio of ionic liquid: ammonia water is 4:1.

[0060] Comparative Example 3: A preparation method of lime fruit extract

[0061] The difference between this preparation method and Example 2 lies in that: in step (2), the extraction solvent is only the ionic liquid and basic alumina, and the ratio of ionic liquid: basic alumina is 4:0.5.

[0062] Comparative Example 4: A preparation method of lime fruit extract

[0063] The difference between this preparation method and Example 2 lies in that: in step (2), the ratio of ionic liquid: ammonia water: basic alumina is 3:1:0.5.

[0064] Comparative Example 5: A preparation method of lime fruit extract

[0065] The difference between this preparation method and that of Example 3 lies in that: in step (2), the ratio of ionic liquid: ammonia water: basic alumina is 7:1:0.5.

[0066] Comparative Example 6: A preparation method of lime fruit extract

[0067] The difference between this preparation method and that of Example 3 lies in that: in step (2), the ionic liquid is trimethylhydroxyethylammonium tetrafluoroborate.

[0068] Comparative Example 7: A preparation method of lime fruit extract

[0069] The difference between this preparation method and that of Example 2 lies in that: in step (2), the ionic liquid is a water-insoluble quaternary amine type ionic liquid tributylhexylammonium tetrafluoroborate.

[0070] Test Example 1:

[0071] Detect the finished product yield of the lime fruit extracts prepared in Examples 2 to 5 and Comparative Examples 1 to 7, and the hesperidin content in the lime fruit extracts.

[0072] Hesperidin extraction rate = hesperidin content in the extract × mass of the extract / mass of the hesperidin extract in the lime peel powder; among them, the hesperidin content in the extract is obtained by high performance liquid chromatography;

[0073] Finished product yield = mass of the hesperidin extract / total mass of the lime peel powder;

[0074] The detection method of hesperidin uses the external standard method of high performance liquid chromatography, that is: using a C18 analytical column (250 mm × 4.6 mm, 5 μm), with octadecylsilane-bonded silica gel as the filler, using acetonitrile - water (22:78) as the mobile phase, and the detection wavelength is 283 nm.

[0075] Take the lime peel powder in step (1) of Example 2, and the hesperidin content in the lime peel powder is detected by high performance liquid chromatography to be 5.54%.

[0076] The detection results of the lime fruit extracts prepared in Examples 2 to 5 and Comparative Examples 1 to 7 are shown in Table 1:

[0077] Table 1 Detection results

[0078]

[0079]

[0080] The finished product yields of the preparation methods in Examples 2 to 5 were 5.07% to 5.26%, the hesperidin content in the lime fruit extract was 95.5% to 96.0%, and both were significantly higher than those in Comparative Examples 1 to 7. Moreover, their hesperidin extraction rates were all greater than 85%. In Comparative Example 4, the mass fraction of the ionic liquid was too low, and the flavonoid compounds could not be fully dissolved in the solution, thus reducing the extraction rate. In Comparative Example 5, too high a mass fraction of the ionic liquid would lead to an increase in the viscosity of the solvent system, reducing the ability of the solvent to penetrate into plant tissues, thereby hindering the dissolution of flavonoid compounds in the solution and further reducing the extraction rate. In Comparative Example 7, an alkaline environment was provided, and the added ionic liquid was insoluble in water. Therefore, the ionic liquid did not play an extraction role, so its extraction rate was low. However, water-soluble impurities were extracted, so its yield was high.

[0081] Test Example 2:

[0082] The zebrafish group without any treatment was used as the control group, the zebrafish group stimulated with glacial acetic acid was used as the model control group, and the model control group treated with the lime fruit extract sample (denoted as PM121-3) extracted in Example 3 with a mass concentration of 0.2% was used as the experimental group. Test system: Wild-type AB strain zebrafish. Zebrafish age: 2 days post-fertilization (2 dpf). Sample size for each group of experiments: 15 tails (N = 10). Adult fish rearing and breeding method: According to the laboratory standard rearing and breeding methods of our company, meeting the requirements of international AAALAC certification (certification number: 001458).

[0083] According to the "Standard Operating Procedure for the Evaluation of the Soothing Efficacy of Zebrafish", the efficacy was tested by the zebrafish soothing efficacy (total movement distance) test method. The detection principle was as follows: Although glacial acetic acid belongs to a weak acid, it has strong penetrability and corrosiveness. Skin contact with glacial acetic acid will cause a stinging and burning sensation. Zebrafish with undeveloped swimming ability were selected, and the use of glacial acetic acid to stimulate zebrafish caused large-area and long-term inflammatory pain, resulting in more movement trajectories and more severe pain. A behavioral analyzer was used to detect the total movement distance of zebrafish to evaluate whether the sample had a soothing efficacy.

[0084] The experimental steps were as follows:

[0085] (1) Zebrafish were randomly selected into 6-well plates, 15 tails per well.

[0086] (2) The sample was administered in water solution, and at the same time, a normal control group and a model control group were set up, with a volume of 3 mL per well.

[0087] (3) Incubate in the dark at 28 °C for 24 h.

[0088] (4) Randomly select 10 zebrafish from each experimental group and transfer them to a 96-well plate. Administer acetic acid in water to establish a zebrafish pain model. Immediately use a behavioral analyzer to measure the movement trajectory of the zebrafish, analyze and collect the total movement distance (D) of the zebrafish, calculate the soothing efficacy of the sample according to the formula, and determine whether it has a soothing efficacy.

[0089]

[0090] The test results are shown in Table 2:

[0091] Table 2 Test Results

[0092] Test Items Test Concentration (%) Efficacy (%) P Value Soothing Efficacy 0.2 50 ＜0.001

[0093] The phenotypic diagram and column chart of the efficacy experiment are shown in Figure 1 and Figure 2 respectively. The test results show that the total movement distance of the hesperidin extract finished product is significantly reduced compared with the model control group, revealing its soothing efficacy.

[0094] The preparation method of the present invention is based on the principle of "like dissolves like". After the ionic liquid is dissolved in water to form a homogeneous solution, basic alumina and ammonia water are added. Since the extract of bitter orange fruit has phenolic hydroxyl groups and is easily soluble in dilute alkali solutions, ammonia water provides an alkaline condition, but strong alkali solutions cannot be used as they will damage its parent nucleus. Basic alumina can provide an alkaline environment and can also adsorb pigment components, reducing the pressure for subsequent elution and impurity removal, and further improving the extraction rate and content of the extract. Among them, the ionic liquid composed of organic cations and inorganic anions has the characteristics of low vapor pressure, high thermal stability and chemical stability, and high potential recovery rate. Using ionic liquid as the extraction solvent does not require volatile organic solvents, has good biocompatibility, and the ionic liquid can be reused after simple treatment. The ultrasonic-assisted extraction method is adopted. Ultrasonic cavitation can accelerate the entry of hesperidin in the bitter orange into the solvent, increase the extraction rate of hesperidin, reduce the amount of extraction solvent used, and is more environmentally friendly. The flavonoid hesperidin in the extract is an active ingredient with strong ability to scavenge 1,1-diphenyl-2-picrylhydrazy (DPPH) free radicals in Citrus grandis Tomentosa. Inflammatory responses play a key role in host defense. When stimulated by pathogen invasion or endotoxin exposure, etc., the immune system can be activated to help the body's functions return to normal. However, when there are too many inflammatory factors in the body, it will disrupt the immune system and cause damage to the body, thus triggering inflammation. The flavonoid hesperidin in the extract of bitter orange fruit has a good therapeutic effect on inflammation, mainly by regulating cellular inflammatory molecules and affecting inflammatory-related signaling pathways such as Mitogen activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) to achieve a soothing effect.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a lime fruit extract, characterized in that, It includes the following steps: (1) Vacuum freeze-dry the lime peel, crush and sieve it to obtain lime peel powder; (2) Take the lime peel powder, add an extraction solvent, mix evenly, and perform ultrasonic-assisted extraction to obtain a crude extract; the extraction solvent is a mixed aqueous solution of an ionic liquid, ammonia water, and basic alumina; the mass ratio of ionic liquid: ammonia water: basic alumina is 4 - 6:1:0.5; The ionic liquid is a water-soluble basic functional ionic liquid, quaternary ammonium ionic liquid, or quaternary phosphonium ionic liquid; The basic functional ionic liquid is 1-butyl-3-methylimidazolium hydroxide; the quaternary ammonium ionic liquid is tributylhexylammonium bromide; the quaternary phosphonium ionic liquid is hexyltributylphosphonium bromide; (3) Centrifuge the crude extract to obtain a supernatant; filter the supernatant by suction to obtain a filtrate; (4) Subject the filtrate to column chromatography treatment and elute to obtain an eluate; (5) Concentrate the eluate under reduced pressure, heat, decolorize, filter, and then vacuum freeze-dry to obtain a lime fruit extract.

2. The preparation method according to claim 1, characterized in that, In step (1), the time for freeze-drying is 48 - 60 h; the mesh number for sieving is 40 - 80 mesh.

3. The preparation method according to claim 1, wherein In step (2), the material-liquid ratio of the lime peel powder to the extraction solvent is 1 g / 15 - 35 mL.

4. The preparation method according to claim 1, characterized in that, In step (2), the extraction temperature is 25°C - 28°C, and the time is 8 - 15 min; the mass fraction of the extraction solvent is 40% - 70%.

5. The preparation method according to claim 1, wherein In step (3), the rotation speed for centrifugation is 6000 - 10000 rpm.

6. The preparation method according to claim 1, characterized in that, In step (4), the column chromatography uses D101 macroporous adsorption resin; the elution is carried out with ethanol having a volume concentration of 48% - 52%.

7. The preparation method according to claim 1, characterized in that, In step (5), the heating temperature is 80°C - 90°C; the decolorization is carried out using activated carbon; the pressure for vacuum freeze-drying is -0.1 MPa, the temperature is -60 - -50°C, pre-freezing is for 6 - 10 h, and drying is carried out until the water content of the lime fruit extract < 1%.

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