Method for simultaneously extracting tartary buckwheat polysaccharide and polyphenol

Abstract

The invention relates to the technical field of extraction of plant-derived polysaccharides and polyphenols, in particular to a method for simultaneously extracting tartary buckwheat polysaccharides and polyphenols. The preparation method comprises the following steps: degreasing tartary buckwheat to obtain degreased tartary buckwheat, mixing the degreased tartary buckwheat with an aqueous two-phase, and extracting while stirring to obtain an extraction phase, the mass percentage of ethanol in the upper phase of the aqueous two-phase is 27.06-33.37%, and the mass percentage of ammonium sulfate in the lower phase of the aqueous two-phase is 24.33-26.53%; the material-liquid ratio of the degreased tartary buckwheat to the two aqueous phases is 1: (50-70) g / mL; the extraction temperature is 40-80 DEG C; the extraction time is 40 to 80 minutes; performing two-phase separation to obtain tartary buckwheat polysaccharide and tartary buckwheat polyphenol. According to the method, the extraction efficiency and the purity of the target component are remarkably improved, meanwhile, the molecular structure integrity of polysaccharide and polyphenol is kept, and the complexity of a subsequent purification link is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of extraction of plant-derived polysaccharides and polyphenols, and in particular to a method for simultaneously extracting tartary buckwheat polysaccharides and polyphenols. Background Art

[0002] Tartary buckwheat (Fagopyrum tataricum) has become a health food ingredient that has attracted much attention due to its rich nutrients and biological activities. The polysaccharides and polyphenols in it have significant antioxidant, hypoglycemic and immune-regulating functions. However, the structure of tartary buckwheat polysaccharides and polyphenols is complex and distributed in the cell wall or in a bound state, making it difficult to separate them efficiently using traditional extraction techniques. At present, polysaccharide extraction usually uses hot water extraction, while polyphenols are mostly extracted with organic solvents. The process of separating the two separately is cumbersome, energy-intensive and difficult to avoid cross-contamination. In addition, the extraction process of polysaccharides and polyphenols is easily affected by conditions such as high temperature and extreme pH, resulting in structural degradation, loss of biological activity, and even low extraction efficiency. At the same time, these methods are usually accompanied by high solvent residues, which are not in line with the technical trend of green and sustainable development.

[0003] Disadvantages of existing technology:

[0004] (1) Insufficient separation selectivity of the target components. Traditional methods cannot take into account the separation efficiency of polysaccharides and polyphenols at the same time, and usually extract single components. The coexistence of polysaccharides and polyphenols in cell walls and bound states makes it difficult to achieve efficient separation of the two by a single extraction method.

[0005] (2) Severe structural damage during the extraction process. The extraction of buckwheat polysaccharides and polyphenols often requires high temperature, extreme pH or strong oxidants, which can easily cause structural degradation of the target components and significantly reduce their biological activity, especially polyphenol compounds that are easily oxidized and lose their function.

[0006] (3) The problem of solvent residue is prominent and environmentally unfriendly. The use of large amounts of organic solvents not only increases the extraction cost, but also may cause environmental pollution. The extracted product needs to be further purified to remove the solvent residue, which increases the complexity of the production process.

[0007] (4) The efficiency and stability of the extraction process are low. Buckwheat polysaccharides and polyphenols are tightly bound in their natural state, and their separation efficiency is significantly affected by factors such as raw material pretreatment, extraction time, and temperature. Existing technologies are difficult to balance efficient extraction and component purity. Summary of the invention

[0008] In order to solve the above problems, the present invention provides a method for simultaneously extracting tartary buckwheat polysaccharides and polyphenols. The method provided by the present invention can efficiently extract high-purity tartary buckwheat polysaccharides and polyphenols at a relatively low temperature.

[0009] In order to achieve the above object, the present invention provides the following technical solutions:

[0010] The present invention provides a method for simultaneously extracting tartary buckwheat polysaccharides and polyphenols, comprising the following steps:

[0011] 1) defatting tartary buckwheat to obtain defatted tartary buckwheat;

[0012] 2) mixing the defatted tartary buckwheat obtained in step 1) with the two-phase water, and extracting under stirring to obtain an extract phase;

[0013] The mass percentage of ethanol in the upper phase of the biphasic aqueous phase is 27.06-33.37%, and the mass percentage of ammonium sulfate in the lower phase is 24.33-26.53%;

[0014] The solid-liquid ratio of the defatted bitter buckwheat to the aqueous two-phase is 1:50-70 g / mL;

[0015] The extraction temperature is 40-80°C;

[0016] The extraction time is 40 to 80 minutes;

[0017] 3) Separating the extracted phase obtained in step 2) into two phases to obtain tartary buckwheat polysaccharides and tartary buckwheat polyphenols.

[0018] Preferably, the mass percentage of ethanol in the upper phase of the biphasic aqueous phase in step 2) is 27.87-33.09%, and the mass percentage of ammonium sulfate in the lower phase is 24.33-26.23%.

[0019] Preferably, in step 2), the solid-liquid ratio of defatted tartary buckwheat to aqueous two-phase is 1:55-65 g / mL.

[0020] Preferably, the solid-liquid ratio of the defatted tartary buckwheat to the aqueous two-phase is 1:60 g / mL.

[0021] Preferably, the extraction temperature in step 2) is 50-70°C.

[0022] Preferably, the extraction temperature is 60°C.

[0023] Preferably, the extraction time in step 2) is 50 to 70 minutes.

[0024] Preferably, the mass percentage of ethanol in the upper phase of the aqueous two-phase in step 2) is 33.09%, and the mass percentage of ammonium sulfate in the lower phase is 24.33%; the solid-liquid ratio of the defatted buckwheat to the aqueous two-phase is 1:70 g / mL; the extraction temperature is 60° C.; and the extraction time is 70 min.

[0025] Preferably, the mass percentage of ethanol in the upper phase of the aqueous two-phase in step 2) is 33.09%, and the mass percentage of ammonium sulfate in the lower phase is 24.33%; the solid-liquid ratio of the defatted buckwheat to the aqueous two-phase is 1:65 g / mL; the extraction temperature is 70° C.; and the extraction time is 70 min.

[0026] Preferably, the defatting conditions in step 1) include: grinding the tartary buckwheat into powder, mixing with petroleum ether, stirring for 24 hours for defatting, replacing the petroleum ether every 6 hours, and then soaking in anhydrous ethanol for 24 hours, and drying to obtain defatted tartary buckwheat.

[0027] The present invention is based on the selective separation principle of the two-phase aqueous system, and constructs a green, low-energy extraction environment through the synergistic effect of ethanol and ammonium sulfate. In this system, ethanol has excellent polyphenol solubility, while ammonium sulfate promotes the separation of polysaccharides through salting out. By utilizing the significant difference in the partition coefficients of polysaccharides and polyphenols in the two-phase aqueous system, the present technology can simultaneously achieve efficient extraction and preliminary separation of the two active ingredients.

[0028] By pretreating the raw materials of buckwheat seeds and optimizing the design of the two-phase aqueous system, the extraction efficiency and purity of the target components were significantly improved, while the molecular structural integrity of polysaccharides and polyphenols was maintained, reducing the complexity of the subsequent purification process. This method has the significant advantages of low cost, strong environmental protection, and simple operation, providing a new idea for the industrial preparation of plant-derived functional ingredients.

[0029] The key points of the present invention are:

[0030] (1) Establishment of the phase diagram of the two-phase aqueous system: The present invention accurately establishes the phase diagram of the two-phase aqueous system through turbidity titration, which not only optimizes the ratio of ethanol and ammonium sulfate, but also determines the distribution characteristics under different ethanol / ammonium sulfate concentrations, providing basic conditions for subsequent extraction process optimization.

[0031] (2) Determination of the optimal mass fraction of ethanol and ammonium sulfate: Through a large number of experimental verifications, the optimal concentration range of ethanol and ammonium sulfate was established, which can significantly improve the extraction efficiency of buckwheat polysaccharides and polyphenols, and provide precise parameters for the optimization of the response surface methodology.

[0032] (3) Optimization of extraction process by single factor and response surface methodology: The extraction process was comprehensively optimized by response surface methodology. Through systematic single factor experiments combined with response surface analysis, the extraction conditions such as temperature, time and material-liquid ratio were accurately optimized. The advantage of this method is that it can effectively improve extraction efficiency, reduce costs, and reduce resource waste. It has high operability and application value.

[0033] Purpose of the present invention:

[0034] (1) Efficient simultaneous extraction of polysaccharides and polyphenols

[0035] The present invention constructs an ethanol-ammonium sulfate aqueous two-phase system and utilizes the difference in the distribution coefficients of the two components in the system to achieve the simultaneous extraction and preliminary separation of buckwheat polysaccharides and polyphenols, thereby improving the extraction efficiency and significantly simplifying the process.

[0036] (2) Protecting the structure and activity of the target component

[0037] By optimizing key parameters such as the composition ratio, temperature and time of the two-phase aqueous system, the extraction process is ensured to be gentle and stable, avoiding damage to the structure of polysaccharides and polyphenols and retaining their original biological activity.

[0038] (3) Achieving green and sustainable extraction process

[0039] Ethanol and ammonium sulfate are used as solvents, both of which are easy to obtain and low in cost. At the same time, the extraction solvent can be recycled, reducing solvent residue and environmental pollution, meeting the requirements of green production.

[0040] (4) Promote industrial application

[0041] The technology of the present invention is simple and easy to implement, suitable for large-scale industrial production, and can be widely used in the fields of functional foods, nutritional supplements, etc., while improving the utilization efficiency of grain resources and promoting the high added value development of the tartary buckwheat industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0043] Figure 1 It is a two-phase water diagram;

[0044] Figure 2 This is a phase zone system diagram. DETAILED DESCRIPTION

[0045] The present invention provides a method for simultaneously extracting tartary buckwheat polysaccharides and polyphenols, comprising the following steps:

[0046] 1) defatting tartary buckwheat to obtain defatted tartary buckwheat;

[0047] 2) mixing the defatted tartary buckwheat obtained in step 1) with the two-phase water, and extracting under stirring to obtain an extract phase;

[0048] The mass percentage of ethanol in the upper phase of the two aqueous phases is 27.06-33.37%, and the mass percentage of ammonium sulfate in the lower phase is 24.33-26.53%;

[0049] The solid-liquid ratio of the defatted bitter buckwheat to the aqueous two-phase is 1:50-70 g / mL;

[0050] The extraction temperature is 40-80°C;

[0051] The extraction time is 40 to 80 minutes;

[0052] 3) Separating the extracted phase obtained in step 2) into two phases to obtain tartary buckwheat polysaccharides and tartary buckwheat polyphenols.

[0053] The present invention defats tartary buckwheat to obtain defatted tartary buckwheat. The present invention does not specifically limit the method used for defatting tartary buckwheat, and those skilled in the art can use conventional methods, such as grinding the tartary buckwheat into powder, mixing it with petroleum ether, stirring it for 24 hours for defatting, replacing the petroleum ether once every 6 hours, and then soaking it in anhydrous ethanol for 24 hours, and drying it to obtain defatted tartary buckwheat.

[0054] The present invention mixes the obtained defatted tartary buckwheat with a two-phase water, extracts under stirring, and obtains an extraction phase; the mass percentage of ethanol in the upper phase of the two-phase water is 27.06-33.37%, and the mass percentage of ammonium sulfate in the lower phase is 24.33-26.53%; the solid-liquid ratio of the defatted tartary buckwheat to the two-phase water is 1:50-70g / mL; the extraction temperature is 40-80°C; and the extraction time is 40-80min. In the present invention, the mass percentage of ethanol in the upper phase of the two-phase water is preferably 27.87-33.09%, and the mass percentage of ammonium sulfate in the lower phase is preferably 24.33-26.23%. In the present invention, the stirring is preferably water bath magnetic stirring, and the rotation speed of the water bath magnetic stirrer is preferably 800rpm. In the present invention, the solid-liquid ratio of the defatted tartary buckwheat to the two-phase water is preferably 1:55-65g / mL. In the present invention, the solid-liquid ratio of the defatted bitter buckwheat to the aqueous two-phase is preferably 1:60 g / mL. In the present invention, the extraction temperature is preferably 50 to 70° C. In the present invention, the extraction temperature is preferably 60° C. In the present invention, the extraction time is preferably 50 to 70 min.

[0055] In the present invention, the mass percentage of ethanol in the upper phase of the two-phase aqueous phase is preferably 33.09%, and the mass percentage of ammonium sulfate in the lower phase is preferably 24.33%; the solid-liquid ratio of the defatted buckwheat to the two-phase aqueous phase is preferably 1:70 g / mL; the extraction temperature is preferably 60°C; and the extraction time is preferably 70 min. In the present invention, the mass percentage of ethanol in the upper phase of the two-phase aqueous phase is preferably 33.09%, and the mass percentage of ammonium sulfate in the lower phase is preferably 24.33%; the solid-liquid ratio of the defatted buckwheat to the two-phase aqueous phase is preferably 1:65 g / mL; the extraction temperature is preferably 70°C; and the extraction time is preferably 70 min.

[0056] The technical solution of the present invention combines the efficient extraction method of the aqueous two-phase system (ATPS) with the optimization process of the response surface methodology to simultaneously extract high-purity polysaccharides and polyphenols from buckwheat. The specific technical steps are preferably as follows:

[0057] (1) Establishment of the phase diagram of the two-phase aqueous system: The phase diagram of the two-phase aqueous system was constructed by turbidity titration. First, select 80% ethanol solution (v / v), mix it with 20g ammonium sulfate and 35mL ultrapure water, determine the initial titration point, and use a water bath magnetic stirrer to ensure that the ethanol and salt phases are fully mixed. During the titration process, gradually add ethanol and observe the clarity of the solution until the solution begins to become turbid. At this time, record the mass of ethanol (m e ) and the total mass of the mixed solution (M H Then, add ultrapure water to the solution until the solution becomes clear again, and record the amount of water added (m 2 ) and the total mass of the system (M z ). Repeat the titration operation and draw a phase diagram based on the data of different turbidity points. Finally, connect the data points with ethanol concentration as the ordinate and ammonium sulfate concentration as the abscissa to complete the construction of the two-phase aqueous phase diagram.

[0058] (2) Determination of ATPS and determination of the optimal ethanol / ammonium sulfate concentration: According to the phase diagram obtained in step (1), multiple groups of ethanol and ammonium sulfate mass fractions (ethanol: 26%-35%, ammonium sulfate: 24%-30%) were selected and mixed to form a two-phase aqueous solution. On this basis, 1g of buckwheat powder sample was added to the two-phase aqueous solution, and the extraction conditions were set as extraction temperature 60°C, extraction time 70min, and solid-liquid ratio 1:70g / mL. After the extraction was completed, the two phases were separated using a separatory funnel, and the concentrations of polyphenols in the upper phase and polysaccharides in the lower phase were measured. The concentrations of polysaccharides and polyphenols were determined by the phenol-sulfuric acid method and the folin-phenol method, respectively, and the concentrations were calculated using the standard curve.

[0059] (3) Single factor experiment and response surface methodology (RSM) to optimize extraction process parameters: The preliminary range of extraction conditions was determined by single factor experiment, focusing on the effects of extraction temperature (40-80℃), extraction time (40-80min), and solid-liquid ratio (1:50-1:70g / mL) on the recovery of buckwheat polysaccharides and polyphenols. Based on the results of the single factor experiment, the response surface methodology was used to optimize the extraction process parameters. The parameters of the response surface methodology include extraction temperature, extraction time, and solid-liquid ratio. The Box-Benhnken experimental design was used to determine the optimal conditions. By combining experiments and mathematical models, the extraction process was optimized and the recovery rate was maximized.

[0060] Single factor optimization design of extraction process parameters

[0061] (1) The extraction temperature was set at 40°C, 50°C, 60°C, 70°C, and 80°C, the solid-liquid ratio was fixed at 1:60 g / mL, and the extraction time was 60 min. The extraction was performed under these conditions. After the extraction was completed, the two phases were separated using a separatory funnel, and then the equilibrium concentrations of the upper phase polyphenols and the lower phase polysaccharides were measured to finally determine the optimal extraction temperature.

[0062] (2) The extraction time was set to 40 min, 50 min, 60 min, 70 min, and 80 min, the extraction temperature was fixed at 70 °C, and the solid-liquid ratio was 1:60 g / mL. The extraction was carried out under these conditions. After the extraction was completed, the two phases were separated using a separatory funnel, and then the equilibrium concentrations of the upper phase polyphenols and the lower phase polysaccharides were measured to finally determine the optimal extraction time.

[0063] (3) The solid-liquid ratio was set to 1:50 g / mL, 1:55 g / mL, 1:60 g / mL, 1:65 g / mL, and 1:70 g / mL, and the extraction temperature was fixed at 60 °C and the extraction time was 70 min. The extraction was performed under these conditions. After the extraction was completed, the two phases were separated using a separatory funnel, and then the equilibrium concentrations of the upper phase polyphenols and the lower phase polysaccharides were measured to determine the optimal extraction solid-liquid ratio.

[0064] Optimization of extraction process parameters by response surface methodology

[0065] According to the single factor experimental results, the RSM parameter range is determined. The value range of RSM parameters is liquid-to-solid ratio (X 1 :50~70g / mL), extraction time (X 2 :60~80min), extraction temperature (X 3 :60~80℃). According to the Box-Benhnken experimental design principle, a three-factor three-level experimental design was established. Based on the results of single-factor experiments, the recovery rates of tartary buckwheat polysaccharides and polyphenols were taken as the response value Y. The three factors of extraction temperature (A), extraction time (B), and solid-liquid ratio (C) were selected, and each factor was set at three levels: low (-1), medium (0), and high (1). The response surface analysis method was used to optimize the process conditions for the extraction of tartary buckwheat polysaccharides and polyphenols in the two-phase system, and the empirical model of the independent variable response was established using a second-order polynomial equation.

[0066]

[0067] Where X i , X j is the independent variable, β 0 is the intercept, β i , β ii and β ij are the coefficients of the linear term, quadratic term, and interaction term, respectively.

[0068] The results of optimizing the extraction process parameters through a single factor response surface experiment in step (3) are as follows: ammonium sulfate: 24.33% (w / w), ethanol: 33.09% (w / w), extraction time: 70 min, extraction temperature: 70° C., and solid-liquid ratio 1:65 g / mL.

[0069] Example

[0070] 1. Materials and Reagents

[0071] The bitter buckwheat sample was "Tongkuiqiao No. 2", provided by the Tongliao Agricultural and Animal Husbandry Science Research Institute of Inner Mongolia. Folinphenol, anhydrous ethanol, petroleum ether (30-60), borax, ammonium sulfate, phenol, and sodium carbonate were all analytically pure and purchased from Tianjin Taijin Technology Co., Ltd.

[0072] 2. Instruments and equipment

[0073] Vacuum freeze dryer (ALpHA 1-2LD PLUS), Marin Christ, Germany; desktop high-speed refrigerated centrifuge (Neofuge 13R), Thermo Fisher Scientific, USA; pulverizer (DFT-200A), Changzhou Panfeng Drying Equipment Co., Ltd.; multi-function microplate reader (Epoch 2), Thermo Fisher Scientific, USA; rotary evaporator (RE-52AA), Shanghai Yarong Biochemical Instrument Factory; digital display constant temperature water bath (XMTD-204), Tianjin Ounuo Instrument Co., Ltd.; electronic balance (TE214S), Sartorius Scientific Instrument Co., Ltd.; ultra-low temperature refrigerator (700SERIES), Thermo, USA; UV-visible spectrophotometer (TU-1810PC89090A), Agilent Technologies, USA; integrated constant temperature heating magnetic stirrer (DF-101S), Gongyi Yuhua Instrument Co., Ltd.

[0074] 3. Sample Pretreatment

[0075] The whole-grain sample of buckwheat was powdered using a high-speed powder grinder and defatted with petroleum ether. The defatting step was to add the dried sample powder to 10 times the volume of petroleum ether, stir with a magnetic stirrer for 24 hours, and replace the petroleum ether every 6 hours. After defatting, the sample was soaked in anhydrous ethanol for 24 hours, then washed by suction filtration, and finally the sample was thoroughly dried to obtain a defatted dry buckwheat sample.

[0076] 4. Extraction of Tartary Buckwheat Polysaccharides and Polyphenols

[0077] A hot water-assisted aqueous two-phase system was used to simultaneously extract soluble polysaccharides and free phenols from buckwheat. Before extraction, single factor experiments were performed to determine the optimal extraction conditions, including the concentrations of ammonium sulfate and ethanol, extraction temperature, time, and liquid-to-solid ratio. The extraction conditions were optimized by response surface methodology (RSM) to obtain the optimal extraction parameters. Through single factor experiments and response surface methodology verification, the optimized extraction conditions can greatly improve the recovery rate of polysaccharides and polyphenols.

[0078] 5. Establishment of ATPS phase diagram

[0079] The phase diagram of the ethanol / ammonium sulfate two-phase system was drawn using turbidity titration to select the appropriate ratio of ethanol and ammonium sulfate. Through multiple experiments, the phase diagram of the system was drawn to help determine the optimal concentrations of ethanol and ammonium sulfate, so as to provide a theoretical basis for subsequent extraction experiments.

[0080] 6. Determination of ATPS

[0081] According to the above phase diagram, multiple mass fraction intervals of ethanol and ammonium sulfate were selected to test the extraction effects under different conditions. 1g of buckwheat powder sample was added to the two-phase aqueous system for extraction, the reaction temperature was 60℃, and the extraction time was 70min. After extraction, the upper and lower phases were separated by a separatory funnel, and the concentrations of polyphenols in the upper phase and polysaccharides in the lower phase were measured by ultraviolet spectrophotometer to determine the optimal extraction conditions.

[0082] 7. Optimization of extraction conditions for single factor experiments

[0083] According to the results of single factor experiments, the optimal extraction temperature, time and material-liquid ratio were determined.

[0084] The extraction temperature was 60℃, the extraction effect of polysaccharides and polyphenols was the best. The extraction time was 70min, the extraction effect was the best. The recovery rate of polysaccharides and polyphenols was the highest when the solid-liquid ratio was 1:60g / mL.

[0085] 8. Optimization of extraction conditions using response surface methodology

[0086] According to the results of the single factor experiment, the response surface methodology (RSM) was used to further optimize the extraction conditions. The response variables were the recovery rates of buckwheat polysaccharides and polyphenols. The experimental design adopted the Box-Benhnken method and set the extraction temperature (X 1 ), extraction time (X 2 ) and material-liquid ratio (X 3 ) as the independent variable, and multiple regression analysis was performed. The optimal extraction conditions were finally obtained as follows: extraction temperature: 70℃; extraction time: 70min; solid-liquid ratio 1:65g / mL.

[0087] Table 1 Response surface experimental factors and level design table

[0088]

[0089] The polysaccharide concentration was determined by the phenol-sulfuric acid method, with glucose as the standard. The principle of this method is that sugar undergoes a dehydration reaction in a concentrated sulfuric acid environment, converting into furfural or hydroxymethylfurfural, and reacting with phenol to form an orange-red substance. The color of this reaction product is positively correlated with the sugar concentration. The polysaccharide concentration is calculated by measuring the absorbance at 490nm by colorimetry. The specific operation is: take 10mg of dry glucose, dissolve it and make it to 10mL to obtain a 1mg / mL glucose solution, and then dilute it to 0.1mg / mL. Pipette 0, 0.2, 0.4, 0.6, 0.8, and 1.0mL of the dilution into a test tube, add pure water to 1mL, then add 1mL of 5% phenol solution and 5mL of concentrated sulfuric acid, mix well, and measure the absorbance at 490nm. The results are calculated according to the standard curve y=0.9041x+0.1954, R 2 =0.9992 calculation.

[0090] The polyphenol concentration was determined by the Folin phenol method, with gallic acid as the standard. Preparation of the standard curve: accurately prepare 0.1 mg / mL gallic acid solution, take 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 mL of the solution in a test tube, add pure water to 1 mL, then add 0.5 mL of Folin phenol solution, 1.5 mL of 20% sodium carbonate solution, and add pure water to make up to 10 mL. After heating the mixture in a 40°C water bath for 2 hours, measure the absorbance at 760 nm. According to the standard curve y = 0.3257x + 0.056, R 2 =0.9997 to calculate the total phenol content in the sample. Dissolve 10 mg of bitter buckwheat polysaccharide to 100 mL, take 0.5 mL of polysaccharide solution to measure the absorbance, and calculate the total phenol content according to the standard curve. Measure the absorbance of the samples in the upper phase and the lower phase respectively, and calculate the corresponding results through the standard curve.

[0091] According to the distribution coefficient (β), phase ratio (K), lower phase (R 1 , Y 1 ) polysaccharide and upper phase (R 2 , Y 2 ) The recovery rate and productivity of polyphenols are used to estimate the composition of the ammonium sulfate / ethanol system. The calculation formulas for these parameters are as follows:

[0092]

[0093]

[0094] In the formula, C b，1 / C t，1 and C b，2 / C t，2are the equilibrium concentrations of polysaccharides and polyphenols in the lower / upper phase, respectively; V b / V t is the volume of the lower phase / upper phase; M is the mass of the powder (mg).

[0095]

[0096] Where X i , X j is the independent variable, β 0 is the intercept, β i , β ii and β ij are the coefficients of the linear term, quadratic term, and interaction term, respectively.

[0097] Design Expert software (12.0) was used to perform multiple regression analysis on the experimental data. Each independent variable and its related response were fitted with a second-order polynomial function to obtain the response surface regression analysis table 2. According to the results of the response surface regression analysis table, the optimal simulation quadratic term equation can be obtained.

[0098] Table 2 Response surface regression analysis results

[0099]

[0100]

[0101] According to the phase diagram, multiple mass fraction intervals of ethanol and ammonium sulfate were selected, and ten groups of examples and one group of comparative examples were set to test the extraction effects under different conditions, respectively, to provide the optimal two-phase concentrations for subsequent single factor experiments and response surface extraction optimization experiments.

[0102] Example 1

[0103] The optimal ammonium sulfate and ethanol mass fractions for the simultaneous extraction of polysaccharides and polyphenols from buckwheat assisted by a hot water two-phase system were determined. In the hot water-assisted two-phase system, the mass fraction of ethanol in the upper phase was 33.09%, and the mass fraction of ammonium sulfate in the lower phase was 24.33%. According to these two mass fractions, a two-phase extraction system was prepared. After 1 g of the sample was mixed with the two-phase system, magnetic stirring extraction was performed in a 70 ° C water bath, the speed was 800 rpm, the extraction time was 70 min, and the solid-liquid ratio was 1:70 g / mL. After the reaction was completed, the two phases were separated using a separatory funnel, and the volume of the extract, the polyphenol concentration in the upper phase, and the polysaccharide concentration in the lower phase were determined.

[0104] Example 2

[0105] Example 2 is similar to Example 1, except that in the hot water-assisted aqueous two-phase system, the mass fraction of ethanol in the upper phase is 27.06%, and the mass fraction of ammonium sulfate in the lower phase is 26.53%.

[0106] Example 3

[0107] Example 3 is similar to Example 1, except that in the hot water-assisted aqueous two-phase system, the mass fraction of ethanol in the upper phase is 27.87%, and the mass fraction of ammonium sulfate in the lower phase is 26.23%.

[0108] Example 4

[0109] Example 4 is similar to Example 1, except that in the hot water-assisted aqueous two-phase system, the mass fraction of ethanol in the upper phase is 28.66%, and the mass fraction of ammonium sulfate in the lower phase is 25.94%.

[0110] Example 5

[0111] Example 5 is similar to Example 1, except that in the hot water-assisted aqueous two-phase system, the mass fraction of ethanol in the upper phase is 29.44%, and the mass fraction of ammonium sulfate in the lower phase is 25.66%.

[0112] Example 6

[0113] Example 6 is similar to Example 1, except that in the hot water-assisted aqueous two-phase system, the mass fraction of ethanol in the upper phase is 30.20%, and the mass fraction of ammonium sulfate in the lower phase is 25.38%.

[0114] Example 7

[0115] Example 7 is similar to Example 1, except that in the hot water-assisted aqueous two-phase system, the mass fraction of ethanol in the upper phase is 30.95%, and the mass fraction of ammonium sulfate in the lower phase is 25.11%.

[0116] Example 8

[0117] Example 8 is similar to Example 1, except that in the hot water-assisted aqueous two-phase system, the mass fraction of ethanol in the upper phase is 31.68%, and the mass fraction of ammonium sulfate in the lower phase is 24.84%.

[0118] Example 9

[0119] Example 9 is similar to Example 1, except that in the hot water-assisted aqueous two-phase system, the mass fraction of ethanol in the upper phase is 32.39%, and the mass fraction of ammonium sulfate in the lower phase is 24.59%.

[0120] Example 10

[0121] Example 10 is similar to Example 1, except that in the hot water-assisted aqueous two-phase system, the mass fraction of ethanol in the upper phase is 33.77%, and the mass fraction of ammonium sulfate in the lower phase is 24.08%.

[0122] Comparative Example 1

[0123] Comparative Example 1 is similar to Example 1, except that the lower phase in the hot water-assisted aqueous two-phase system is selected to be ammonium bisulfate with a mass fraction of 25.23%.

[0124] In summary, after obtaining the optimal two-phase concentration, single-factor experiments were carried out to optimize the extraction time, temperature and solid-liquid ratio of hot water-assisted two-phase extraction.

[0125] Embodiment 11

[0126] The single factor method was used to optimize the hot water-assisted two-phase aqueous system for simultaneous extraction of tartary buckwheat polysaccharides and polyphenols. 1 g of tartary buckwheat sample was taken according to the extraction conditions: 24.33% (w / w) ammonium sulfate of Example 1, 33.09% (w / w) ethanol of Example 1, extraction temperature 60°C, extraction time 70 min, solid-liquid ratio 1:70 g / mL, and placed in a water bath magnetic stirrer for simultaneous extraction. The upper phase was tartary buckwheat polyphenols, and the lower phase was tartary buckwheat polysaccharides. The concentrations of the components in the two phases were determined.

[0127] Example 12

[0128] Example 12 is similar to Example 11, except for the extraction conditions: extraction temperature 40° C., extraction time 60 min, and solid-liquid ratio 1:60 g / mL.

[0129] Example 13

[0130] Example 13 is similar to Example 11, except for the extraction conditions: extraction temperature 50° C., extraction time 60 min, and solid-liquid ratio 1:60 g / mL.

[0131] Embodiment 14

[0132] Example 14 is similar to Example 11, except for the extraction conditions: extraction time 60 min, solid-liquid ratio 1:60 g / mL.

[0133] Embodiment 15

[0134] Example 15 is similar to Example 11, except for the extraction conditions: extraction temperature 70° C., extraction time 60 min, and solid-liquid ratio 1:60 g / mL.

[0135] Example 16

[0136] Example 16 is similar to Example 11, except for the extraction conditions: extraction temperature 80° C., extraction time 60 min, and solid-liquid ratio 1:60 g / mL.

[0137] Embodiment 17

[0138] Example 17 is similar to Example 11, except for the extraction conditions: extraction temperature 70° C., extraction time 40 min, and solid-liquid ratio 1:60 g / mL.

[0139] Embodiment 18

[0140] Example 18 is similar to Example 11, except for the extraction conditions: extraction temperature 70° C., extraction time 50 min, and solid-liquid ratio 1:60 g / mL.

[0141] Embodiment 19

[0142] Example 19 is similar to Example 11, except for the extraction conditions: extraction temperature 70° C., extraction time 60 min, and solid-liquid ratio 1:60 g / mL.

[0143] Embodiment 20

[0144] Example 20 is similar to Example 11, except for the extraction conditions: extraction temperature 70° C., extraction time 70 min, and solid-liquid ratio 1:60 g / mL.

[0145] Embodiment 21

[0146] Example 21 is similar to Example 11, except for the extraction conditions: extraction temperature 70° C., extraction time 80 min, and solid-liquid ratio 1:60 g / mL.

[0147] Embodiment 22

[0148] Example 22 is similar to Example 11, except for the extraction conditions: solid-liquid ratio 1:50 g / mL.

[0149] Embodiment 23

[0150] Example 23 is similar to Example 11, except for the extraction conditions: solid-liquid ratio 1:55 g / mL.

[0151] Embodiment 24

[0152] Example 24 is similar to Example 11, the only difference being the extraction conditions: solid-liquid ratio 1:60 g / mL.

[0153] Embodiment 25

[0154] Example 25 is similar to Example 11, except for the extraction conditions: solid-liquid ratio 1:65 g / mL.

[0155] Embodiment 26

[0156] Example 26 is similar to Example 11, except for the extraction conditions: solid-liquid ratio 1:70 g / mL.

[0157] After obtaining the extraction time, temperature and solid-liquid ratio of the best embodiment, the extraction conditions were finally optimized by response surface methodology (RSM).

[0158] Embodiment 27

[0159] Response surface methodology was used to optimize the hot water-assisted aqueous two-phase system for simultaneous extraction of tartary buckwheat polysaccharides and polyphenols. 1 g of tartary buckwheat sample was placed in a water bath magnetic stirrer for simultaneous extraction according to the extraction conditions: 33.09% (w / w) ethanol of Example 1, 24.33% (w / w) ammonium sulfate of Example 1, extraction temperature 70°C, extraction time 70 min, solid-liquid ratio 1:65 g / mL, and extracted simultaneously. The upper phase was tartary buckwheat polyphenols, and the lower phase was tartary buckwheat polysaccharides. The recovery rates of the upper and lower phases were determined.

[0160] Embodiment 28

[0161] Example 28 is similar to Example 27, except for the extraction conditions: extraction temperature 40° C., extraction time 60 min, and solid-liquid ratio 1:60 g / mL.

[0162] Embodiment 29

[0163] Example 29 is similar to Example 27, except for the extraction conditions: extraction temperature 50° C., extraction time 60 min, and solid-liquid ratio 1:60 g / mL.

[0164] Embodiment 30

[0165] Example 30 is similar to Example 27, except for the extraction conditions: extraction temperature 60° C., extraction time 60 min, and solid-liquid ratio 1:60 g / mL.

[0166] Embodiment 31

[0167] Example 31 is similar to Example 27, except for the extraction conditions: extraction time 60 min, solid-liquid ratio 1:60 g / mL.

[0168] Embodiment 32

[0169] Example 32 is similar to Example 27, except for the extraction conditions: extraction time 60 min, solid-liquid ratio 1:60 g / mL.

[0170] Embodiment 33

[0171] Example 33 is similar to Example 27, except for the extraction conditions: extraction time 40 min, solid-liquid ratio: 1:60 g / mL.

[0172] Embodiment 34

[0173] Example 34 is similar to Example 27, except for the extraction conditions: extraction time 50 min, solid-liquid ratio 1:60 g / mL.

[0174] Embodiment 35

[0175] Example 35 is similar to Example 27, except for the extraction conditions: extraction time 60 min, solid-liquid ratio 1:60 g / mL.

[0176] Embodiment 36

[0177] Example 36 is similar to Example 27, except for the extraction conditions: solid-liquid ratio 1:60 g / mL.

[0178] Embodiment 37

[0179] Example 37 is similar to Example 27, except for the extraction conditions: extraction time 80 min, solid-liquid ratio 1:60 g / mL.

[0180] Embodiment 38

[0181] Example 38 is similar to Example 27, except for the extraction conditions: extraction temperature 60° C., extraction time 60 min, and solid-liquid ratio 1:70 g / mL.

[0182] Embodiment 39

[0183] Example 39 is similar to Example 27, except for the extraction conditions: extraction temperature 60° C., solid-liquid ratio 1:70 g / mL.

[0184] Embodiment 40

[0185] Example 40 is similar to Example 27, except for the extraction conditions: extraction temperature 60° C., solid-liquid ratio 1:60 g / mL.

[0186] Embodiment 41

[0187] Example 41 is similar to Example 27, except for the extraction conditions: extraction temperature 60° C., solid-liquid ratio 1:60 g / mL.

[0188] Embodiment 42

[0189] Example 42 is similar to Example 27, except for the extraction conditions: extraction temperature 60° C., solid-liquid ratio 1:60 g / mL.

[0190] Embodiment 43

[0191] Example 43 is similar to Example 27, except for the extraction conditions: solid-liquid ratio 1:60 g / mL.

[0192] Embodiment 44

[0193] Example 44 is similar to Example 27, except for the extraction conditions: solid-liquid ratio 1:60 g / mL.

[0194] Embodiment 45

[0195] Example 45 is similar to Example 27, except for the extraction conditions: solid-liquid ratio 1:60 g / mL.

[0196] Comparative Example 2

[0197] Comparative Example 2 is similar to Example 27, except that only 70°C hot water is used for extraction for 70 min, and the solid-liquid ratio is 1:20 g / mL.

[0198] By determining the optimal extraction mass fractions of ethanol and ammonium sulfate and conducting a single factor preliminary optimization experiment, the preliminary optimal extraction conditions obtained are: ethanol concentration 33.09% (w / w), ammonium sulfate concentration 24.33% (w / w) (Example 1), extraction temperature 60°C, extraction time 70 minutes, and solid-liquid ratio 1:70g / mL (Example 11). Subsequently, the response surface methodology (RSM) was used to further optimize the extraction conditions, and the optimal extraction conditions finally obtained were: ethanol concentration 33.09% (w / w), ammonium sulfate concentration 24.33% (w / w), extraction temperature 70°C, extraction time 70 minutes, and solid-liquid ratio 1:65g / mL (Example 27). Under this condition, when hot water-assisted two-phase system extraction is used, the recovery rate of polysaccharides is the highest, and the recovery rate of polyphenols is second.

[0199] Table 3 Effects of ammonium sulfate and ethanol mass fraction on the extraction of polysaccharides and polyphenols

[0200] Example Polysaccharide concentration (mg / mL) Polyphenol concentration (mg / mL) Polysaccharide recovery rate (%) Polyphenol recovery rate (%) 1 <![CDATA[11.540±0.079 a ]]> <![CDATA[0.993±0.003 b ]]> 77.61 79.17 2 <![CDATA[3.453±0.025 e ]]> <![CDATA[0.674±0.002 f ]]> 50.82 51.18 3 <![CDATA[4.703±0.005 d ]]> <![CDATA[0.717±0.002 d ]]> 53.44 53.75 4 <![CDATA[4.955±0.004 d ]]> <![CDATA[0.734±0.003 d ]]> 55.10 55.36 5 <![CDATA[4.315±0.004 d ]]> <![CDATA[0.756±0.004 d ]]> 50.90 56.78 6 <![CDATA[6.336±0.003 c ]]> <![CDATA[0.775±0.003 d ]]> 62.22 58.42 7 <![CDATA[6.433±0.002 c ]]> <![CDATA[1.026±0.003 a ]]> 62.71 82.36 8 <![CDATA[4.463±0.002 d > <![CDATA[0.836±0.002 c > 52.30 64.12 9 <![CDATA[6.225±0.004 c ]]> <![CDATA[0.814±0.003 c ]]> 60.09 62.03 10 <![CDATA[7.633±0.002 b ]]> <![CDATA[0.876±0.003 c ]]> 64.91 66.25 Comparative Example Polysaccharide concentration (mg / mL) Polyphenol concentration (mg / mL) Polysaccharide recovery rate (%) Polyphenol recovery rate (%) 1 <![CDATA[4.982±0.003 d ]]> <![CDATA[0.689±0.003 i ]]> 55.35 52.41

[0201] Note: Different lowercase letters indicate significant differences in the simultaneous extraction of buckwheat polysaccharides and polyphenols under different conditions (P<0.05).

[0202] By selecting the optimal mass fraction range of ethanol and ammonium sulfate in the phase region according to the phase diagram (ethanol concentration 26%-35%, ammonium sulfate concentration 24%-30%), and fixing other extraction conditions, ten groups of two-phase extraction experiments were carried out. According to the changes in the polyphenol concentration of the upper phase and the polysaccharide concentration of the lower phase, the optimal extraction conditions of Example 1 were obtained: the ethanol concentration of the upper phase was 33.09% (w / w), and the ammonium sulfate concentration of the lower phase was 24.33% (w / w). Under this condition, the polysaccharide concentration of the lower phase and the polyphenol concentration of the upper phase both reached the highest values, which was shown as the best embodiment. In contrast, in Comparative Example 1, the salt phase selected was ammonium bisulfate, and the experimental results showed that the extraction effect was not as good as ammonium sulfate. The determination of the optimal mass fraction of ethanol / ammonium sulfate is the basis of single-factor experiments and response surface optimization experiments. Therefore, Example 1 is the optimal condition for hot water-assisted two-phase extraction, and the optimal mass fractions of ethanol in the upper phase and ammonium sulfate in the lower phase are established.

[0203] Table 4 Optimization of extraction process parameters by single factor experimental design

[0204] Example Polysaccharide concentration (mg / mL) Polyphenol concentration (mg / mL) 11 <![CDATA[10.225±0.002 a > <![CDATA[0.089±0.003 b ]]> 12 <![CDATA[2.724±0.003 f ]]> <![CDATA[0.015±0.006 e ]]> 13 <![CDATA[2.995±0.003 f ]]> <![CDATA[0.010±0.005 e ]]> 14 <![CDATA[5.998±0.001 c ]]> <![CDATA[0.022±0.008 d ]]> 15 <![CDATA[4.942±0.002 d ]]> <![CDATA[0.011±0.015 e ]]> 16 <![CDATA[3.361±0.001 e ]]> <![CDATA[0.017±0.005 e ]]> 17 <![CDATA[2.263±0.003 f ]]> <![CDATA[0.041±0.009 c ]]> 18 <![CDATA[2.372±0.003 f ]]> <![CDATA[0.028±0.004 d <!-- 12 -->]]> 19 <![CDATA[1.214±0.001 g ]]> <![CDATA[0.023±0.004 d ]]> 20 <![CDATA[4.606±0.002 d ]]> <![CDATA[0.098±0.005 a ]]> 21 <![CDATA[0.927±0.001 c ]]> <![CDATA[0.031±0.011 cd ]]> 22 <![CDATA[4.429±0.039 d ]]> <![CDATA[0.017±0.66 e ]]> 23 <![CDATA[1.226±0.030 g ]]> <![CDATA[0.081±0.01 b ]]> 24 <![CDATA[3.240±0.085 e ]]> <![CDATA[0.007±0.01 f ]]> 25 <![CDATA[4.418±0.020 d ]]> <![CDATA[0.007±0.00 f ]]> 26 <![CDATA[8.331±0.044 b ]]> <![CDATA[0.042±0.01 c ]]>

[0205] Note: Different lowercase letters indicate significant differences in the simultaneous extraction of buckwheat polysaccharides and polyphenols under different conditions (P<0.05).

[0206] By determining the optimal extraction mass fractions of ethanol and ammonium sulfate, and combining the single factor preliminary optimization experiment, the optimal extraction conditions after preliminary optimization are obtained as Example 11: ethanol concentration 33.09% (w / w), ammonium sulfate concentration 24.33% (w / w), extraction temperature 60℃, extraction time 70min, and solid-liquid ratio 1:70g / mL. The experimental results show that although the tartary buckwheat polysaccharides and polyphenols cannot be extracted efficiently at the same time when the hot water-assisted two-phase extraction method is used, compared with other single extraction methods, the hot water-assisted two-phase extraction can maximize the simultaneous extraction of high-purity tartary buckwheat polysaccharides and polyphenols under the conditions of low cost, low energy consumption and low pollution. After single factor experimental optimization, the mass fraction of the two-phase system when the lower phase polysaccharide concentration reaches the highest value is taken as the main basis, and the upper phase polyphenol concentration is second. Finally, Example 11 is determined to be the optimal extraction process parameters.

[0207] Table 5 Optimization of extraction process parameters by response surface design

[0208] Example Polysaccharide concentration (mg / mL) Polyphenol concentration (mg / mL) Polysaccharide recovery rate (%) Polyphenol recovery rate (%) 27 10.572 1.952 96.34 33.07 28 1.478 0.355 68.90 23.06 29 2.464 1.037 74.46 16.47 30 3.137 0.408 71.41 33.83 31 2.531 0.431 88.75 17.87 32 2.223 0.437 78.21 21.96 33 4.452 0.411 84.63 23.03 34 2.230 0.236 94.44 32.18 35 2.558 1.005 82.35 9.81 36 7.327 1.014 89.29 10.50 37 6.701 0.827 86.90 10.11 38 8.155 0.816 93.49 20.10 39 7.851 0.824 93.47 28.80 40 7.650 1.972 93.77 37.16 41 9.016 1.885 95.69 38.05 42 8.529 1.914 95.35 39.08 43 6.247 1.887 94.38 35.63 44 8.358 1.972 91.82 40.13 Comparative Example Polysaccharide concentration (mg / mL) Polyphenol concentration (mg / mL) Polysaccharide recovery rate (%) Polyphenol recovery rate (%) 2 5.513 1.435 80.25 20.65

[0209] Example 27 was optimized by single factor experiment and response surface methodology, and the optimal process parameters for hot water-assisted aqueous two-phase extraction were: ammonium sulfate concentration 24.33% (w / w), ethanol concentration 33.09% (w / w), extraction time 70 min, extraction temperature 70 ° C, and solid-liquid ratio 1: 65 g / mL. Under this condition, the recovery rate of tartary buckwheat polysaccharides was the highest, and the recovery rate of polyphenols was relatively high. The hot water-assisted aqueous two-phase extraction method can efficiently extract tartary buckwheat polysaccharides and polyphenols at the same time under low cost, low energy consumption, and low pollution conditions. Its extraction effect and purity are better than those of the traditional hot water single extraction method in Comparative Example 2, and it has significant advantages in efficiency, purity, energy consumption, and cost.

[0210] The experimental data were fitted with multiple regression using Design Expert 13.0 software, and the following quadratic polynomial regression equations were obtained, which were used to predict the recovery rates of buckwheat polysaccharides and polyphenols, respectively:

[0211] Y=94.20-0.096A-0.45B+3.09C-1.56AB-4.63AC+0.5920BC-14.35A 2 -

[0212] 8.47B 2 +5.06C 2 ;

[0213] Y=38.01-5.48A+3.06B+0.66C-2.34AB-5.86AC+3.27BC-2.92A 2 -

[0214] 12.29B 2 -13.34C 2 .

[0215] Through these regression models, the optimal extraction process parameters were finally predicted under the conditions of Example 1: the predicted recovery rate of tartary buckwheat polysaccharides was 96.34%, and the recovery rate of tartary buckwheat polyphenols was 33.03%. Response surface analysis showed that the interaction between extraction temperature, extraction time and solid-liquid ratio had a significant effect on the recovery rate of polysaccharides and polyphenols. By combining single factor experiments with response surface experiments, Example 27 was optimized as the optimal process conditions for hot water-assisted two-phase aqueous extraction of tartary buckwheat polysaccharides and polyphenols.

[0216] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for simultaneously extracting tartary buckwheat polysaccharides and polyphenols, characterized in that: The following steps are involved: 1) defatting tartary buckwheat to obtain defatted tartary buckwheat; 2) mixing the defatted tartary buckwheat obtained in step 1) with the two-phase water, and extracting under stirring to obtain an extract phase; The mass percentage of ethanol in the upper phase of the two aqueous phases is 27.06-33.37%, and the mass percentage of ammonium sulfate in the lower phase is 24.33-26.53%; The solid-liquid ratio of the defatted bitter buckwheat to the aqueous two-phase is 1:50-70 g / mL; The extraction temperature is 40-80°C; The extraction time is 40 to 80 minutes; 3) Separating the extracted phase obtained in step 2) into two phases to obtain tartary buckwheat polysaccharides and tartary buckwheat polyphenols.

2. The method according to claim 1, characterized in that In the step 2), the mass percentage of ethanol in the upper phase of the biphasic water is 27.87-33.09%, and the mass percentage of ammonium sulfate in the lower phase is 24.33-26.23%.

3. The method according to claim 1, characterized in that In the step 2), the solid-liquid ratio of defatted tartary buckwheat to aqueous two-phase is 1:55-65 g / mL.

4. The method according to claim 1 or 3, characterized in that: The solid-liquid ratio of the defatted tartary buckwheat to the aqueous two-phase is 1:60 g / mL.

5. The method according to claim 1, characterized in that: The extraction temperature in step 2) is 50-70°C.

6. The method according to claim 1 or 5, characterized in that: The extraction temperature is 60°C.

7. The method according to claim 1, characterized in that The extraction time in step 2) is 50 to 70 minutes.

8. The method according to claim 1, characterized in that In the step 2), the mass percentage of ethanol in the upper phase of the two-phase aqueous solution is 33.09%, and the mass percentage of ammonium sulfate in the lower phase is 24.33%; the solid-liquid ratio of the defatted buckwheat to the two-phase aqueous solution is 1:70 g / mL; the extraction temperature is 60° C.; and the extraction time is 70 min.

9. The method according to claim 1, characterized in that: In the step 2), the mass percentage of ethanol in the upper phase of the two-phase aqueous solution is 33.09%, and the mass percentage of ammonium sulfate in the lower phase is 24.33%; the solid-liquid ratio of the defatted buckwheat to the two-phase aqueous solution is 1:65 g / mL; the extraction temperature is 70° C.; and the extraction time is 70 min.

10. The method according to claim 1, characterized in that The defatting conditions of step 1) include: grinding the tartary buckwheat into powder, mixing with petroleum ether, stirring for 24 hours to defatted, replacing the petroleum ether once every 6 hours, and then soaking in anhydrous ethanol for 24 hours, and drying to obtain defatted tartary buckwheat.

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