Extraction method and application of sugar-controlling component in mulberry leaves

Abstract

The invention provides an extraction method and application of a sugar-controlling component in mulberry leaves, and the extraction method comprises the following steps: mixing mulberry leaf powder and an acidic ethanol solution, and then carrying out ultrasonic extraction to prepare a first extracting solution and a first extracting residue; carrying out enzymolysis treatment on the first extraction residue, and collecting a second extraction solution; combining the first extracting solution and the second extracting solution, concentrating and decoloring to obtain a decolored solution; carrying out microfiltration, nanofiltration and membrane concentration on the decolored solution, and then drying; the enzymolysis treatment comprises primary enzymolysis treatment and secondary enzymolysis treatment; a composite decolorizing agent is added in the decolorizing process; the preparation method of the composite decolorizing agent comprises the following steps: mixing the activated carbon and the attapulgite, pickling, and calcining to obtain a first mixture; mixing and reacting the first mixture, chitosan and acetic acid. According to the method, the extraction process of the mulberry leaf powder is controlled, so that the sugar-controlled component in the mulberry leaves is efficiently extracted.

Description

Technical Field

[0001] The present application relates to the technical field of plant extracts, and in particular to a method for extracting sugar-controlling components from mulberry leaves and its application. Background Art

[0002] Mulberry leaves are the leaves of the mulberry tree, a plant of the Moraceae family. They are a type of plant resource that can be used as both medicine and food. Mulberry leaves are rich in a variety of nutrients and active substances, and have the advantages of being natural and non-toxic, and having a wide range of pharmacological effects.

[0003] Alkaloids are an important active ingredient in mulberry leaves, among which piperidine alkaloids are the main components, especially 1-deoxynojirimycin, which is the characteristic alkaloid of mulberry leaves and has the effects of lowering blood sugar, anti-oxidation, and lowering blood lipids.

[0004] In the related art, during the extraction of mulberry leaf alkaloids, some substances such as pigments will be dissolved simultaneously under the action of solvents or instruments, deepening the color of the extract and affecting the subsequent content detection, separation and purification work. Therefore, it is necessary to decolorize the extract.

[0005] At present, the commonly used decolorization methods for active ingredient extraction are activated carbon method, hydrogen peroxide method and macroporous resin method. The hydrogen peroxide method is a chemical decolorization method that uses its oxidative properties to destroy the pigment structure for decolorization, but the active ingredients may also be destroyed at the same time. The cost of macroporous resin decolorization is relatively high, and the subsequent processing process is relatively complicated.

[0006] Application Contents

[0007] The present application is made in view of the above-mentioned problems, and its purpose is to provide a method for extracting sugar-controlling components in mulberry leaves. The mulberry leaf extract prepared by the extraction method has a high content of sugar-controlling components.

[0008] Specifically, the first aspect of the present application provides a method for extracting sugar-controlling components in mulberry leaves, comprising the following steps:

[0009] Mixing mulberry leaf powder and acidic ethanol solution and then performing ultrasonic extraction to obtain a first extract and a first extract residue;

[0010] Performing enzymatic hydrolysis on the first extraction residue and collecting a second extraction liquid;

[0011] After combining the first extract and the second extract, microfiltration, nanofiltration, membrane concentration and decolorization are performed to obtain a decolorized solution;

[0012] The decolorizing solution is concentrated and then dried;

[0013] The enzymatic hydrolysis treatment includes a first enzymatic hydrolysis treatment and a second enzymatic hydrolysis treatment;

[0014] Adding a composite decolorizing agent during the decolorizing process;

[0015] The preparation method of the composite decolorizing agent comprises the following steps:

[0016] The activated carbon and attapulgite are mixed, and then acid-washed and calcined to obtain a first mixture;

[0017] The first mixture, chitosan and acetic acid are mixed and reacted.

[0018] According to one of the technical solutions of this application, at least the following beneficial effects are achieved:

[0019] The cell wall of mulberry leaf cells contains cellulose and hemicellulose, and the cell membrane contains protein, which constitute the natural barrier of the cell and hinder the release of sugar-controlling components in mulberry leaves. The present application first uses ultrasonic treatment to make the cell plasma flow and the cells vibrate, thereby thinning or rupturing the cell wall, which is beneficial to the dissolution of intracellular active ingredients, and when the enzymatic treatment is subsequently performed, the enzyme can be more easily contacted with cellulose, hemicellulose and protein, promoting the hydrolysis process, thereby facilitating the enzymatic hydrolysis of the cell wall and cell membrane, reducing the dissolution resistance of the intracellular active ingredients, thereby facilitating the release and extraction of intracellular sugar-controlling components and increasing the extraction rate.

[0020] Therefore, the combination of ultrasonic extraction and enzymatic hydrolysis can complement each other's advantages and extract more sugar-controlling components under mild and controllable conditions. It has no effect on the structure and physicochemical properties of the extract. The obtained mulberry leaf extract retains the active ingredients in the mulberry leaf to a large extent and has a strong blood sugar-lowering effect.

[0021] The present application performs an acid-washing treatment on a mixture of activated carbon and attapulgite, thereby removing impurities distributed in the attapulgite channels, unblocking the pores in the attapulgite, increasing the pore volume, weakening the original interlayer bond force, cracking the layered lattice, unblocking the pores, and improving the adsorption performance; the present application utilizes chitosan to compound the activated carbon and attapulgite, tightly combining the activated carbon, attapulgite and chitosan, which is beneficial to the adsorption and separation of pigments, thereby greatly reducing the impurity content in the extract.

[0022] According to some embodiments of the present application, the pH of the acidic ethanol solution is 4.0-5.0.

[0023] DNJ is an alkaloid compound that can form soluble salts and dissolve under acidic conditions, thereby greatly improving the extraction rate of DNJ.

[0024] According to some embodiments of the present application, the volume fraction of ethanol in the acidic ethanol solution is 60% to 70%.

[0025] According to some embodiments of the present application, the volume mass ratio of the acidic ethanol solution and the mulberry leaf powder is 10 mL to 30 mL: 1 g.

[0026] According to some embodiments of the present application, the temperature of the ultrasonic extraction is 50°C to 70°C.

[0027] Within this temperature range, the cell wall is easily softened, the permeability of the cell membrane is changed, and the dissolution of intracellular substances is promoted. Too high a temperature causes some sugar-controlling components to be decomposed, thereby reducing the extraction rate of sugar-controlling components.

[0028] According to some embodiments of the present application, cellulase and pectinase are selected in the first enzymatic hydrolysis treatment.

[0029] Cellulose is the main component of plant cell walls and a natural barrier to the dissolution of active molecules such as intracellular polysaccharides and alkaloids, which hinders the extraction process. Using cellulase to treat mulberry leaves can degrade the cellulose components in the cell wall, making the structure of the cell wall loose, thereby reducing the mass transfer resistance of the effective ingredients from the cell to the extraction medium and promoting the extraction of the effective ingredients.

[0030] According to some embodiments of the present application, the pH of the first enzymatic hydrolysis treatment is 4.0-6.0.

[0031] According to some embodiments of the present application, the time of the first enzymatic hydrolysis treatment is 40 min to 50 min.

[0032] According to some embodiments of the present application, the mass ratio of the enzyme to the first extraction residue during the first enzymatic hydrolysis process is 0.6 to 1.6:100.

[0033] If the enzyme concentration is too low, the extraction effect will be affected; if the enzyme concentration is too high, the extraction rate will decrease. This is because the enzyme concentration is too high, the enzyme and partially hydrolyzed cellulose and hemicellulose will wrap the sugar-controlling components, which is not conducive to the dissolution of the sugar-controlling components.

[0034] According to some embodiments of the present application, the temperature of the first enzymatic hydrolysis treatment is 45°C to 55°C.

[0035] According to some embodiments of the present application, papain is selected in the second enzymatic hydrolysis treatment.

[0036] According to some embodiments of the present application, the pH of the second enzymatic hydrolysis treatment is 5.5-6.5.

[0037] According to some embodiments of the present application, the time for the second enzymatic hydrolysis treatment is 60 min to 70 min.

[0038] According to some embodiments of the present application, the mass ratio of the enzyme to the first extraction residue during the second enzymatic hydrolysis process is 0.4-0.6:100.

[0039] According to some embodiments of the present application, the temperature of the second enzymatic hydrolysis treatment is 45°C to 55°C.

[0040] According to some embodiments of the present application, the mass ratio of the activated carbon to attapulgite is 10:3-4.

[0041] According to some embodiments of the present application, the mass ratio of the activated carbon to chitosan is 1:0.8-1.

[0042] According to some embodiments of the present application, the calcination temperature is 300°C to 500°C.

[0043] According to some embodiments of the present application, the calcination time is 1 h to 3 h.

[0044] According to some embodiments of the present application, the pore size of the microfiltration membrane is 0.01 μm to 0.1 μm.

[0045] According to some embodiments of the present application, the molecular weight cutoff of the nanofiltration is above 50,000 Da.

[0046] According to some embodiments of the present application, the molecular weight cutoff of the membrane concentration is above 4000 Da.

[0047] According to some embodiments of the present application, the decolorization temperature is 40°C to 50°C.

[0048] When the temperature is low, the diffusion rate of the pigment in the solution is the main factor determining the decolorization rate. As the temperature rises, the viscosity of the polysaccharide solution decreases, which is conducive to the diffusion of the pigment in the solution and makes decolorization and adsorption easier. In the high temperature area, the shift of the adsorption equilibrium becomes the main factor affecting the decolorization rate. Adsorption is an exothermic process, and rising temperature is not conducive to decolorization.

[0049] The second aspect of the present application provides a mulberry leaf extract obtained by the extraction method described in the first aspect of the present application.

[0050] The third aspect of the present application provides the use of the mulberry leaf extract as described in the second aspect of the present application in extracting sugar-controlling foods and / or sugar-controlling health products. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0052] Obviously, the following descriptions are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in the field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0053] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially the same structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the following description is provided for those skilled in the art to fully understand the present application and is not intended to limit the subject matter described in the claims.

[0054] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0055] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0056] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0057] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0058] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0059] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0060] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0061] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0062] The polysaccharide content was determined by the phenol-sulfuric acid method.

[0063] The DNJ content was determined by liquid chromatography.

[0064] The dosage of mulberry leaf powder in the examples and comparative examples of the present application is 1000 g.

[0065] Cellulase was purchased from Shanghai Yuanye Biotechnology Co., Ltd. (S10041), 50 U / mg.

[0066] Pectinase was purchased from Shanghai Yuanye Biotechnology Co., Ltd. (S10007), 50000u / g.

[0067] Papain was purchased from Shanghai Yuanye Biotechnology Co., Ltd. (S10011), 800 U / mg.

[0068] The mesh number of mulberry leaf powder in this application is 300 mesh.

[0069] Attapulgite (CAS No.: 12174-11-7).

[0070] Example 1

[0071] This embodiment is a method for extracting sugar-controlling components from mulberry leaves, which consists of the following steps:

[0072] S1, mulberry leaf powder and acidic ethanol solution are mixed and then ultrasonically extracted (temperature is 60°C, time is 40min, ultrasonic power is 200W), after the extraction is completed, solid-liquid separation is performed to obtain a first extract and a first extraction residue;

[0073] The properties and parameters of the acidic ethanol solution in this step are as follows:

[0074] The pH of the acidic ethanol solution is 4.5 (adjusted by concentrated hydrochloric acid (36%)), the volume fraction of ethanol is 65%; the volume mass ratio of the acidic ethanol solution to the mulberry leaf powder is 30 mL: 1 g;

[0075] S2, enzymatically hydrolyzing the first extraction residue, separating the solid and the liquid after the enzymatic hydrolysis is completed, and collecting the second extraction liquid;

[0076] The enzymatic hydrolysis treatment includes a first enzymatic hydrolysis treatment and a second enzymatic hydrolysis treatment;

[0077] The parameters during the first enzymatic hydrolysis process were as follows:

[0078] Cellulase and pectinase (mass ratio of 1:1), pH of 4.0, time of 50 min, mass ratio of enzyme (total mass of cellulase and pectinase) to the first extraction residue of 1.2:100 and temperature of 50°C.

[0079] The parameters during the first enzymatic hydrolysis process were as follows:

[0080] Papain was selected, pH was 6.0, time was 65 min, the mass ratio of enzyme to first extraction residue was 0.5:100 and the temperature was 50°C.

[0081] S3, combining the first extract and the second extract, and concentrating (concentrating to 1 / 3 of the original volume) to obtain a concentrated solution;

[0082] The concentrated solution and the composite decolorizing agent are mixed and then decolorized, and the solid-liquid separation is performed to obtain a decolorized solution; the decolorized solution is microfiltered (filter membrane pore size is 0.1 μm, PVDF filter membrane), nanofiltered (molecular weight cutoff is 50000Da) and membrane concentrated (molecular weight cutoff is 4000Da), and crystallized at -4°C (adding ethanol with a volume fraction of 99%, the volume ratio of ethanol to the concentrated solution is 5:1, and the crystallization time is 1h), solid-liquid separation is performed, and the solid phase is collected and dried;

[0083] The mass ratio of the concentrated solution to the composite decolorizing agent is 100mL:2g.

[0084] The decolorization temperature was 45°C and the decolorization time was 60 min.

[0085] The preparation method of the composite decolorizing agent comprises the following steps:

[0086] The activated carbon (mesh size is 300 mesh) and attapulgite are mixed and then acid-washed (using acetic acid for acid washing, and the volume mass ratio of acetic acid to activated carbon is 10 mL: 1 g), washed with water after the acid washing, dried after washing (dried at 150° C. for 2 h), and calcined after drying (calcination atmosphere is nitrogen, calcination temperature is 400° C., and time is 3 h) to obtain a first mixture;

[0087] Chitosan and water are mixed to form a chitosan solution (mass fraction is 1%), and the first mixture and the chitosan solution are mixed; acetic acid is then added to the mixed phase (the mass ratio of acetic acid to chitosan is 1.2:1), and after mixing evenly, glutaraldehyde is added (the mass ratio of glutaraldehyde to chitosan is 1:100), stirred for 3 hours, separated into solid and liquid, washed and dried (the drying temperature is 80°C).

[0088] The mass ratio of activated carbon, attapulgite and chitosan is 10:3.5:8.7.

[0089] Example 2

[0090] This embodiment is a method for extracting sugar-controlling components from mulberry leaves, which consists of the following steps:

[0091] S1, mulberry leaf powder and acidic ethanol solution are mixed and then ultrasonically extracted (temperature is 60°C, time is 40min, ultrasonic power is 200W), after the extraction is completed, solid-liquid separation is performed to obtain a first extract and a first extraction residue;

[0092] The properties and parameters of the acidic ethanol solution in this step are as follows:

[0093] The pH of the acidic ethanol solution is 4.0 (adjusted by concentrated hydrochloric acid (36%)), the volume fraction of ethanol is 70%; the volume mass ratio of the acidic ethanol solution to the mulberry leaf powder is 30 mL: 1 g;

[0094] S2, enzymatically hydrolyzing the first extraction residue, separating the solid and the liquid after the enzymatic hydrolysis is completed, and collecting the second extraction liquid;

[0095] The enzymatic hydrolysis treatment includes a first enzymatic hydrolysis treatment and a second enzymatic hydrolysis treatment;

[0096] The parameters during the first enzymatic hydrolysis process were as follows:

[0097] Cellulase and pectinase (mass ratio of 1:1), pH of 4.0, time of 50 min, mass ratio of enzyme to first extraction residue of 0.6:100 and temperature of 55°C.

[0098] The parameters during the first enzymatic hydrolysis process were as follows:

[0099] Papain, pH 6.5, time 70 min, mass ratio of enzyme (total mass of cellulase and pectinase) to first extraction residue 0.4:100 and temperature 55°C were selected.

[0100] S3, combining the first extract and the second extract, and concentrating (concentrating to 1 / 3 of the original volume) to obtain a concentrated solution;

[0101] The concentrated solution and the composite decolorizing agent are mixed and then decolorized, and the solid-liquid separation is performed to obtain a decolorized solution; the decolorized solution is microfiltered (filter membrane pore size is 0.1 μm, PVDF filter membrane), nanofiltered (molecular weight cutoff is 50000Da) and membrane concentrated (molecular weight cutoff is 4000Da), and crystallized at -4°C (adding ethanol with a volume fraction of 99%, the volume ratio of ethanol to the concentrated solution is 5:1, and the crystallization time is 1h), solid-liquid separation is performed, and the solid phase is collected and dried;

[0102] The mass ratio of the concentrated solution to the composite decolorizing agent is 100mL:1g.

[0103] The decolorization temperature was 45°C and the decolorization time was 60 min.

[0104] The preparation method of the composite decolorizing agent comprises the following steps:

[0105] The activated carbon (mesh size is 300 mesh) and attapulgite are mixed and then acid-washed (using acetic acid for acid washing, and the volume mass ratio of acetic acid to activated carbon is 10 mL: 1 g), washed with water after the acid washing, dried after washing (dried at 150° C. for 2 h), and calcined after drying (calcination atmosphere is nitrogen, calcination temperature is 400° C., and time is 3 h) to obtain a first mixture;

[0106] Chitosan and water are mixed to form a chitosan solution (mass fraction is 1%), and the first mixture and the chitosan solution are mixed; acetic acid is then added to the mixed phase (the mass ratio of acetic acid to chitosan is 1.2:1), and after mixing evenly, glutaraldehyde is added (the mass ratio of glutaraldehyde to chitosan is 1:100), stirred for 3 hours, separated into solid and liquid, washed and dried (the drying temperature is 80°C).

[0107] The mass ratio of activated carbon, attapulgite and chitosan is 10:3:10.

[0108] Example 3

[0109] This embodiment is a method for extracting sugar-controlling components from mulberry leaves, which consists of the following steps:

[0110] S1, mulberry leaf powder and acidic ethanol solution are mixed and then ultrasonically extracted (temperature is 60°C, time is 40min, ultrasonic power is 200W), after the extraction is completed, solid-liquid separation is performed to obtain a first extract and a first extraction residue;

[0111] The properties and parameters of the acidic ethanol solution in this step are as follows:

[0112] The pH of the acidic ethanol solution is 5.0 (adjusted by concentrated hydrochloric acid (36%)), the volume fraction of ethanol is 65%; the volume mass ratio of the acidic ethanol solution to the mulberry leaf powder is 30 mL: 1 g;

[0113] S2, enzymatically hydrolyzing the first extraction residue, separating the solid and the liquid after the enzymatic hydrolysis is completed, and collecting the second extraction liquid;

[0114] The enzymatic hydrolysis treatment includes a first enzymatic hydrolysis treatment and a second enzymatic hydrolysis treatment;

[0115] The parameters during the first enzymatic hydrolysis process were as follows:

[0116] Cellulase and pectinase (mass ratio of 1:1), pH of 4.0, time of 50 min, mass ratio of enzyme (total mass of cellulase and pectinase) to the first extraction residue of 1.6:100 and temperature of 55°C.

[0117] The parameters during the first enzymatic hydrolysis process were as follows:

[0118] Papain was selected, pH was 5.5, time was 70 min, the mass ratio of enzyme to first extraction residue was 0.4:100 and the temperature was 55°C.

[0119] S3, combining the first extract and the second extract, and concentrating (concentrating to 1 / 3 of the original volume) to obtain a concentrated solution;

[0120] The concentrated solution and the composite decolorizing agent are mixed and then decolorized, and the solid-liquid separation is performed to obtain a decolorized solution; the decolorized solution is microfiltered (filter membrane pore size is 0.1 μm, PVDF filter membrane), nanofiltered (molecular weight cutoff is 50000Da) and membrane concentrated (molecular weight cutoff is 4000Da), and crystallized at -4°C (adding ethanol with a volume fraction of 99%, the volume ratio of ethanol to the concentrated solution is 5:1, and the crystallization time is 1h), solid-liquid separation is performed, and the solid phase is collected and dried;

[0121] The mass ratio of the concentrated solution to the composite decolorizing agent is 100mL:1.5g.

[0122] The decolorization temperature was 45°C and the decolorization time was 60 min.

[0123] The preparation and extraction method of the composite decolorizing agent comprises the following steps:

[0124] The activated carbon (mesh size is 300 mesh) and attapulgite are mixed and then acid-washed (using acetic acid for acid washing, and the volume mass ratio of acetic acid to activated carbon is 10 mL: 1 g), washed with water after the acid washing, dried after washing (dried at 150° C. for 2 h), and calcined after drying (calcination atmosphere is nitrogen, calcination temperature is 400° C., and time is 3 h) to obtain a first mixture;

[0125] Chitosan and water are mixed to form a chitosan solution (mass fraction is 1%), and the first mixture and the chitosan solution are mixed; acetic acid is then added to the mixed phase (the mass ratio of acetic acid to chitosan is 1.2:1), and after mixing evenly, glutaraldehyde is added (the mass ratio of glutaraldehyde to chitosan is 1:100), stirred for 3 hours, separated into solid and liquid, washed and dried (the drying temperature is 80°C).

[0126] The mass ratio of activated carbon, attapulgite and chitosan is 10:3:8.

[0127] Example 4

[0128] This embodiment is a method for extracting sugar-controlling components from mulberry leaves, which differs from Embodiment 1 in that:

[0129] The mass ratio of activated carbon, attapulgite and chitosan is 10:4:8.

[0130] Example 5

[0131] This embodiment is a method for extracting sugar-controlling components from mulberry leaves, which differs from Embodiment 1 in that:

[0132] The mass ratio of activated carbon, attapulgite and chitosan is 10:3.3:9.

[0133] Comparative Example 1

[0134] This comparative example is a method for extracting sugar-controlling components from mulberry leaves, which differs from Example 1 in that:

[0135] The composite decolorizing agent of this comparative example is prepared and extracted by the following method:

[0136] The activated carbon (mesh size is 300 mesh) is acid-washed (using acetic acid for acid washing, and the volume mass ratio of acetic acid to activated carbon is 10 mL: 1 g), washed with water after the acid washing, dried after washing (dried at 150° C. for 2 h), and calcined after drying (calcination atmosphere is nitrogen, calcination temperature is 400° C., and time is 3 h) to obtain a first mixture;

[0137] Chitosan and water are mixed to form a chitosan solution (mass fraction is 1%), and the first mixture and the chitosan solution are mixed; acetic acid is then added to the mixed phase (the mass ratio of acetic acid to chitosan is 1.2:1), and after mixing evenly, glutaraldehyde is added (the mass ratio of glutaraldehyde to chitosan is 1:100), stirred for 3 hours, separated into solid and liquid, washed and dried (the drying temperature is 80°C).

[0138] The mass ratio of activated carbon to chitosan is 10:8.7.

[0139] Comparative Example 2

[0140] This comparative example is a method for extracting sugar-controlling components from mulberry leaves, which differs from Example 1 in that:

[0141] The composite decolorizing agent of this comparative example is prepared by the following method:

[0142] The preparation method of the composite decolorizing agent comprises the following steps:

[0143] The attapulgite is acid-washed (using acetic acid for acid washing, and the volume mass ratio of acetic acid to attapulgite is 10 mL: 1 g), washed with water after the acid washing, dried after washing (dried at 150° C. for 2 h), and calcined after drying (calcination atmosphere is nitrogen, calcination temperature is 400° C., and time is 3 h) to obtain a first mixture;

[0144] Chitosan and water are mixed to form a chitosan solution (mass fraction is 1%), and the first mixture and the chitosan solution are mixed; acetic acid is then added to the mixed phase (the mass ratio of acetic acid to chitosan is 1.2:1), and after mixing evenly, glutaraldehyde is added (the mass ratio of glutaraldehyde to chitosan is 1:100), stirred for 3 hours, separated into solid and liquid, washed and dried (the drying temperature is 80°C).

[0145] The mass ratio of attapulgite to chitosan is 3.5:8.7.

[0146] Comparative Example 3

[0147] This comparative example is a method for extracting sugar-controlling components from mulberry leaves, which differs from Example 1 in that:

[0148] The composite decolorizing agent of this comparative example is prepared by the following method:

[0149] The activated carbon (mesh size is 300 mesh) and attapulgite are mixed and then acid washed (using acetic acid for acid washing, the volume mass ratio of acetic acid to activated carbon is 10mL:1g), washed with water after the acid washing, dried after washing (dried at 150℃ for 2h), and calcined after drying (the calcination atmosphere is nitrogen, the calcination temperature is 400℃, and the time is 3h) to obtain a composite decolorizer.

[0150] The mass ratio of activated carbon to attapulgite is 10:3.5.

[0151] Comparative Example 4

[0152] This comparative example is a method for extracting sugar-controlling components from mulberry leaves, which differs from Example 1 in that:

[0153] The decolorizing agent of this comparative example adopts activated carbon.

[0154] Comparative Example 5

[0155] This comparative example is a method for extracting sugar-controlling components from mulberry leaves, which differs from Example 1 in that:

[0156] The decolorizing agent of this comparative example is attapulgite.

[0157] The total mass, DNJ and polysaccharide mass of the extracts in this application are shown in Table 1.

[0158] Table 1

[0159]

[0160]

[0161] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for extracting sugar-controlling components from mulberry leaves, characterized in that: The following steps are involved: Mixing mulberry leaf powder and acidic ethanol solution and then performing ultrasonic extraction to obtain a first extract and a first extract residue; Performing enzymatic hydrolysis on the first extraction residue and collecting a second extraction liquid; After combining the first extract and the second extract, microfiltration, nanofiltration, membrane concentration and decolorization are performed to obtain a decolorized solution; The decolorizing solution is concentrated and then dried; The enzymatic hydrolysis treatment includes a first enzymatic hydrolysis treatment and a second enzymatic hydrolysis treatment; Adding a composite decolorizing agent during the decolorizing process; The preparation method of the composite decolorizing agent comprises the following steps: The activated carbon and attapulgite are mixed, and then acid-washed and calcined to obtain a first mixture; The first mixture, chitosan and acetic acid are mixed and reacted.

2. The extraction method according to claim 1, characterized in that The parameters of the acidic ethanol solution include at least one of the following (1) to (3); (1) The pH of the acidic ethanol solution is 4.0 to 5.0; (2) The volume fraction of ethanol in the acidic ethanol solution is 60% to 70%; (3) The volume mass ratio of the acidic ethanol solution to the mulberry leaf powder is 10 mL to 30 mL: 1 g.

3. The extraction method according to claim 1, characterized in that The temperature of the ultrasonic extraction is 50°C to 70°C.

4. The extraction method according to claim 1, characterized in that The parameters of the enzymatic treatment include at least one of the following (1) to (5); (1) cellulase and pectinase are selected in the first enzymatic hydrolysis treatment; (2) The pH of the first enzymatic hydrolysis treatment is 4.0 to 6.0; (3) The duration of the first enzymatic hydrolysis treatment is 40 to 50 minutes; (4) During the first enzymatic hydrolysis process, the mass ratio of the enzyme to the first extraction residue is 0.6 to 1.6:100; (5) The temperature of the first enzymatic hydrolysis treatment is 45°C to 55°C.

5. The extraction method according to claim 1, characterized in that The parameters of the enzymatic treatment include at least one of the following (1) to (5); (1) papain is selected in the second enzymatic hydrolysis treatment; (2) The pH of the second enzymatic hydrolysis treatment is 5.5 to 6.5; (3) The second enzymatic hydrolysis treatment lasts for 60 to 70 minutes; (4) During the second enzymatic hydrolysis process, the mass ratio of the enzyme to the first extraction residue is 0.4-0.6:100; (5) The temperature of the second enzymatic hydrolysis treatment is 45°C to 55°C.

6. The extraction method according to claim 1, characterized in that The mass ratio of the activated carbon to the attapulgite is 10:3-4; The mass ratio of the activated carbon to chitosan is 1:0.8-1; The pore size of the microfiltration membrane is 0.01 μm to 0.1 μm; The molecular weight cut-off of the nanofiltration is above 50000Da; The molecular weight cut-off of the membrane concentration is above 4000Da.

7. The extraction method according to claim 1, characterized in that The calcination temperature is 300°C to 500°C; The calcination time is 1 h to 3 h.

8. The extraction method according to claim 1, characterized in that The decolorization temperature is 40°C to 50°C.

9. A mulberry leaf extract rich in sugar-controlling ingredients, characterized in that: The extract is obtained by the extraction method according to any one of claims 1 to 8.

10. Use of the mulberry leaf extract according to claim 9 in the preparation of sugar-controlling foods and / or sugar-controlling health products.

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