Extraction method of flavonoid glycoside and preparation method of flavonoid glycoside-rich beverage

Abstract

The application provides a flavonoid glycoside extraction method and a preparation method of a flavonoid glycoside-rich beverage. When extracting the flavonoid glycoside, first, the flavonoid raw materials and water are added into a leaching tank according to a set ratio, soaked for half an hour, and combined with temperature control to make the flavonoid glycoside dissolve more thoroughly. When testing the flavonoid content of the raw materials, the application does not use alcohol solution method, but simulates the flavonoid hydrolysis process under heating. Not only hot water is added into a beaker containing the raw materials to be tested, but also the temperature is kept at 85-88 DEG C for 30 min, so that the flavonoid glycoside dissolved by hydrolysis is the most, and the flavonoid glycoside content of the raw materials obtained by measurement is close to the actual situation. When preparing the flavonoid glycoside-rich beverage, the plant flavonoid glycoside extraction liquid is also sterilized and stored, so that the flavonoid glycoside-rich beverage is suitable for food processing. After sterilization, the temperature of the plant flavonoid glycoside extraction liquid is rapidly reduced, so that the flavonoid glycoside is prevented from being converted into flavonoid aglycone under high temperature.

Description

Technical Field

[0001] This invention relates to the field of essential technologies for human life, specifically to a method for extracting flavonoid glycosides and a method for preparing beverages rich in flavonoid glycosides. Background Technology

[0002] Flavonoids are secondary metabolites widely found in plants, possessing various biological activities such as antioxidation, anti-inflammation, antitumor activity, blood pressure reduction, and prevention of neurological disorders. Currently, over 15,000 natural flavonoids have been isolated and identified from plants. Natural flavonoids often exist in glycoside form, with only a small portion existing as free aglycones.

[0003] Flavonoid glycosides (flavonoids bound to glucosides) are generally readily soluble in highly polar solvents such as water, methanol, and ethanol, but have poor solubility in nonpolar organic solvents such as benzene and chloroform. Furthermore, the hydrolysis and breakage of glycosidic bonds at high temperatures will convert flavonoid glycosides into water-insoluble flavonoid aglycones. The hydrolysis time of flavonoids bound to rutin or sophoridine is also different from that of flavonoid glycosides. Therefore, how to obtain more flavonoid glycosides through water solubility without converting flavonoid glycosides into flavonoid aglycones is a problem that urgently needs to be solved.

[0004] Furthermore, selecting the right raw materials for enriching flavonoid glycosides is also a challenge. Currently, the most common method for detecting flavonoids in plant materials is ultraviolet-visible spectrophotometry (UV-VIS). GB / T20574-2006 "Determination of Total Flavonoid Content in Propolis" (currently obsolete) involves adding ethanol to the propolis sample to prepare the test material. This method measures the alcohol-soluble plant flavonoid aglycones, including glucose-bound flavonoid glycosides and the total amount of flavonoid aglycones. However, flavonoid aglycones are insoluble in water and difficult to absorb, leading to an inflated flavonoid content reading. GB19777-2013 "Geographical Indication Products of Shanxi Lao" The standard for testing flavonoid glycosides in aged vinegar refers to the testing method for fermented liquids. However, flavonoid plant raw materials are generally solids, with only a few being liquids (such as sea buckthorn juice). Typically, during the enrichment of flavonoid glycosides, heating is performed to eliminate water-insoluble flavonoid precursors, allowing only water-soluble flavonoid glycosides to be selected. The flavonoid glycoside testing method for Shanxi aged vinegar does not include this process. Therefore, neither of these standards is suitable for testing the flavonoid content of plant raw materials. Consequently, the flavonoid glycoside measurement method needs improvement. Without a suitable flavonoid glycoside testing method for raw materials, it is impossible to obtain beverages enriched with flavonoid glycosides.

[0005] Therefore, there is a need for a method that can both enrich flavonoid glycosides and measure the flavonoid glycoside content of raw materials by simulating actual hydrolysis. Summary of the Invention

[0006] This invention addresses the problem of flavonoid glycoside enrichment and measurement by providing a method for extracting flavonoid glycosides and a method for preparing flavonoid glycoside-rich beverages. During flavonoid glycoside extraction, flavonoid raw materials and water are first added to an extraction tank according to a set ratio and soaked for half an hour, with temperature control to ensure more thorough dissolution of flavonoid glycosides. When testing the flavonoid content of raw materials, this invention does not use the alcohol dissolution method but simulates a heated flavonoid hydrolysis process. Boiling water is added to the beaker containing the raw materials to be tested, and the temperature is maintained at 85-88℃ for 30 minutes to maximize the hydrolysis and dissolution of flavonoid glycosides, ensuring the measured flavonoid glycoside content closely approximates actual values. In preparing flavonoid glycoside-rich beverages, this invention also sterilizes and preserves the plant flavonoid glycoside extract, making the beverage suitable for food processing. Simultaneously, sterilization rapidly lowers the temperature of the plant flavonoid glycoside extract to prevent the high-temperature conversion of flavonoid glycosides into flavonoid aglycones.

[0007] This invention provides a method for extracting flavonoid glycosides, comprising the following steps: S1. Place the plant raw materials or plant mixture raw materials and water in an extraction tank at a mass ratio of 1:(7.5~10) and soak for 20~40 minutes; The flavonoid content of plant raw materials or plant mixtures was tested using the water-soluble flavonoid content measurement method during material selection and on-site testing. S2. Raise the temperature in the extraction tank to 85-88°C for 35-40 minutes, then lower the temperature to 48-50°C for 30-32 minutes. After cooling, maintain the temperature at 48-50°C for 120-125 minutes to obtain the first solid-liquid mixture. S3: Perform the first round of extraction on the first solid-liquid mixture. The first round of extraction includes three extractions. The temperature, heating time, cooling time and holding time after cooling are the same as in step S2 for each extraction. After the first extraction, the extract is transferred to the first extract storage tank. During the second extraction, the same weight of water as in step S1 is added to the extraction tank and the extraction method is the same as the first extraction. The extract is then transferred to the second extract storage tank. During the third extraction, the same weight of water as in step S1 is added to the extraction tank and the extraction method is the same as the first extraction. The extract is then transferred to the third extract storage tank. S4: Empty the extraction tank and perform the second round of extraction. The second round of extraction also includes three extractions. The temperature, heating time, cooling time and holding time after cooling are the same as in step S2 for each extraction. Add the same weight of plant raw material or plant mixture raw material as in step S1 and the extract in the first extract tank to the extraction tank and add water to make the weight of the liquid in the extraction tank the same as the weight of the water in step S1. Then perform the first extraction in the second round. After extraction, transfer the extract to the first extract tank. During the second extraction, the extract in the second extract tank is added to the extraction tank and water is added to make the weight of the liquid in the extraction tank the same as the weight of the water in step S1 before extraction is performed. After extraction, the extract is transferred to the second extract tank. During the third extraction, the extract in the third extract storage tank is added to the extraction tank and water is added to make the weight of the liquid in the extraction tank the same as the weight of the water in step S1 before extraction is performed. After extraction, the extract is transferred to the third extract storage tank. S5: Empty the extraction tank and proceed with the third extraction. The method for the third extraction is the same as that for the second extraction. After the third extraction, the liquid in the first extraction tank is the flavonoid extract. The liquid in the second and third extraction tanks is reserved for the next extraction of flavonoids.

[0008] The method for extracting flavonoid glycosides according to the present invention, as a preferred embodiment, includes the following steps in step S1 for measuring water-soluble flavonoid glycosides: SⅠ. Preparation of the test solution: Weigh 30g of the raw and auxiliary materials to be tested into a 500ml beaker, add 300ml of boiling water and weigh to obtain the weight. Heat the beaker and keep it at a constant temperature of 85-88℃ for 30min. Then add water to the weight. After cooling, filter to obtain the test solution. Take 5.00g of the test solution into a 100ml beaker, adjust the pH to 7.1-7.2 with sodium hydroxide solution, transfer it into a 100ml volumetric flask, dilute to the mark with water, and shake well to obtain the sample solution; SⅡ, The total flavonoid content, calculated as rutin, was obtained by measuring the sample solution using ultraviolet-visible spectrophotometry.

[0009] The method for extracting flavonoid glycosides according to the present invention, as a preferred embodiment, includes the following steps in step SⅡ: SⅡ-1. Pipette 0.00 mL, 0.50 mL, 1.00 mL, 2.00 mL, 3.00 mL, and 4.00 mL of rutin standard working solution, equivalent to 0.00 mg, 0.10 mg, 0.20 mg, 0.40 mg, 0.60 mg, and 0.80 mg of anhydrous rutin, respectively, into 25 mL stoppered colorimetric tubes. Add water to a final volume of 10 mL, add 1.0 mL of sodium nitrite solution, mix well, and let stand for 6 min. Then add 1.0 mL of aluminum nitrate solution, mix well, and let stand for 6 min. Next, add 4.0 mL of sodium hydroxide solution, add water to the mark, mix well, and let stand for 15 min. Using a 1 cm cuvette, adjust the zero point with a reagent blank, and measure the absorbance at a wavelength of 510 nm. Plot a working curve or calculate a regression equation with absorbance as the ordinate and the mass of rutin as the abscissa. SⅡ-2. Preheat the spectrophotometer 20 minutes in advance. Pipette two 2.00 mL aliquots of the sample solution into two 25 mL stoppered colorimetric tubes, add water to 10 mL, add 1.0 mL of sodium nitrite solution to each aliquot and mix well, then let stand for 6 minutes. Do not add 1.0 mL of aluminum nitrate solution to one aliquot as a sample blank, mix well and let stand for 6 minutes. Add 4.0 mL of sodium hydroxide solution to both aliquots, then add water to the mark and mix well, let stand for 15 minutes. Adjust the zero point with a 1 cm cuvette using the reagent blank, and measure the absorbance at a wavelength of 510 nm. Measure the absorbance of the test solution and subtract the absorbance of the sample blank. Find the mass m1 of total flavonoids in the sample solution from the working curve or calculate it using the regression equation. Total flavonoid content in the sample (calculated as rutin): ; in: X represents the total flavonoid content in the raw material sample to be tested, calculated as rutin, in milligrams per 100 grams (g). m1 is the total flavonoids in the test solution, calculated as rutin, obtained from the working curve or calculated by the regression equation, in milligrams (mg). m represents the mass of the raw material sample to be tested, in grams (g).

[0010] The method for extracting flavonoid glycosides described in this invention, as a preferred embodiment, In step S1, the concentration of the sodium hydroxide solution is 10 g / L; In step S2, the concentration of sodium nitrite solution is 50 g / L, the concentration of aluminum nitrate solution is 100 g / L, the concentration of sodium hydroxide solution is 200 g / L, and the concentration of sodium nitrite solution is 50 g / L. The concentration of the rutin standard solution used is 0.20 mg / mL, which is obtained by pipetting 10.00 mL of the rutin standard stock solution into a 100 mL volumetric flask and diluting it to the mark with water. The concentration of the rutin standard stock solution is 2.00 mg / mL. The preparation method is as follows: Weigh 0.2000 g of anhydrous rutin that has been dried to constant weight under reduced pressure at 120℃ and place it in a 100 mL volumetric flask. Dissolve it in ethanol solution and dilute to the mark. Shake well to obtain the anhydrous rutin, which is rutin or rutin with a mass fraction greater than 95% and ethanol solution with a volume fraction of 60%.

[0011] In the preferred embodiment of the flavonoid glycoside extraction method of the present invention, the plant material or plant mixture can be either solid or liquid. In steps S2 to S5, the method for measuring flavonoid glycosides in the liquid in the extraction storage tank and the flavonoid glycoside extract is as follows: Step SⅠ is as follows: Weigh 5.00g of the mixed sample into a 100mL beaker, adjust the pH value to 7.1-7.2 with sodium hydroxide solution, transfer it into a 100mL volumetric flask, dilute to the mark with water, and shake well. Step SⅡ is the same as the method for measuring water-soluble flavonoid glycosides.

[0012] In a preferred embodiment of the flavonoid glycoside extraction method of the present invention, in step S1, the plant raw materials or plant mixture raw materials include any one or more of the following: buckwheat bran, buckwheat hulls, kudzu root, sea buckthorn pulp, dried hawthorn, wolfberry fruit, and sophora japonica flowers. After step S5, the liquid in the second extract storage tank and the third extract tank is added to the first extraction tank and the second extraction tank of the first extraction in the next extraction of flavonoid glycosides, respectively. When the weight of the extract is less than that of the water in step S1, water is added.

[0013] The method for extracting flavonoids according to the present invention, as a preferred embodiment, uses a mixture of tartary buckwheat hulls, tartary buckwheat bran and kudzu root as the plant mixture raw material, or a mixture of sea buckthorn pulp, tartary buckwheat hulls and wolfberry fruit, or a mixture of dried hawthorn, tartary buckwheat hulls and kudzu root as the plant raw material, and Sophora japonica flowers as the plant raw material.

[0014] In the preferred embodiment of the flavonoid glycoside extraction method of the present invention, when the plant mixture raw material is a mixture of buckwheat hulls, buckwheat bran and kudzu root, the mass ratio is (7-9):(1-3):(2-4). When the raw materials for the plant mixture are a mixture of sea buckthorn pulp, buckwheat hulls and wolfberry fruit, the mass ratio is (1-3): (7-9): (2-4); When the raw materials of the plant mixture are a mixture of dried hawthorn, buckwheat hulls and kudzu root, the mass ratio is (2-4): (7-9): (1-3).

[0015] This invention provides a method for preparing a flavonoid-rich beverage based on a flavonoid glycoside extraction method, which further includes the following steps: S6. Use a diatomaceous earth filter to filter the flavonoid glycoside extract to obtain a plant flavonoid glycoside extract; S7. The flavonoid glycoside extract is filled into a transfer container to obtain the filled flavonoid glycoside extract; S8. Sterilize the flavonoid glycoside extract by raising the temperature from room temperature to 85-87 degrees Celsius within 40-42 minutes and maintaining it for 30-32 minutes. After sterilization, open the sterilization cabinet door and quickly cool it to below 50 degrees Celsius for 30-32 minutes.

[0016] The present invention discloses a method for preparing a flavonoid-rich beverage based on a flavonoid glycoside extraction method, characterized in that: in step S6, the fine and coarse diatomaceous earth in the diatomaceous earth filter are of the same quality. In step S7, 25KG reusable containers are used for filling; In step S8, the sterilization process is as follows: the temperature is raised from room temperature to 85-87°C within 40-42 minutes, maintained for 30-32 minutes, sterilization is completed, the sterilization cabinet door is opened, and the temperature is cooled to below 50°C for 30-32 minutes. It also includes step S9: S9. Prepare 10-14% sweetener in a reusable container and fill the flavonoid glycosides into small bottles to obtain a flavonoid glycoside-rich beverage. The sweeteners include honey and / or white sugar and / or monk fruit juice.

[0017] Currently, the ultraviolet-visible spectrophotometry method is commonly used in China for determining flavonoid content. GB / T20574-2006, "Determination of Total Flavonoid Content in Propolis" (currently expired), specifies the method for preparing the test solution by dissolving propolis in ethanol. The specific method is as follows: All propolis blocks (approximately 50g to 100g) from the same sample were frozen until hardened and brittle. They were then broken into small pieces with a wooden mallet, pulverized using a high-speed tissue homogenizer (4.3), and passed through a 14-mesh sieve. The mixture was thoroughly mixed. Approximately 1g of the pulverized propolis sample was weighed, accurate to 1mg. It was placed in a beaker, and approximately 30mL of ethanol (3.1) was added. The beaker was heated in a 65°C water bath for approximately 45 minutes, stirring to dissolve the propolis. After cooling to room temperature, the supernatant was filtered through rapid filter paper. The beaker, funnel, filter residue, and filter paper were washed with a small amount of ethanol (3.1) until the filtrate was colorless. Finally, the mixture was diluted to 50mL with ethanol (3.1), shaken well, and ready for analysis.

[0018] Appendix C of GB19777-2013 "Geographical Indication Product Shanxi Aged Vinegar" is the method for measuring the flavonoid content of Shanxi Aged Vinegar (liquid after fermentation). The preparation method of the test solution is as follows: Weigh 5.00g of the mixed sample into a 100mL beaker, adjust to neutral with sodium hydroxide solution (C.2.2), add 2 more drops, transfer to a 100mL volumetric flask, dilute to the mark with water, shake well, and set aside.

[0019] Although GB / T20574-2006 specifies the method for measuring the flavonoid content of propolis blocks, it extracts alcohol-soluble plant flavonoid aglycones, glucose-bound flavonoids, and flavonoid aglycones. The measured flavonoid content reflects the content of total flavonoids, including both water-soluble and water-insoluble portions. However, the absorption effect of water-insoluble flavonoid aglycones in the human body is unknown, resulting in a relatively high measured value but only a moderate effect. GB19777-2013 measures the flavonoids in vinegar, but the testing method for liquid vinegar after fermentation is not applicable to solid plant raw materials.

[0020] During plant growth, secondary metabolites of flavonoids gradually combine with glucosides from water-insoluble flavonoid aglycones to form flavonoid glycosides. As the plant grows, flavonoid aglycones may also combine with rutin and sophoroside to form different flavonoid glycosides. These flavonoid glycosides are characterized by good water solubility and are easily absorbed by the human body.

[0021] Plants increase water solubility by gradually adding sugar, but in the human body, this becomes a process that requires the reverse process (sugar removal) for absorption.

[0022] Flavonoid aglycones: Highly lipid-soluble, but poorly absorbed. Flavonoid glycosides (monoglucosides): After the aglycone binds to a glucose, its water solubility improves, and it begins to have the potential to be actively recognized.

[0023] Flavonoid glycosides (rutin glycosides, sophoridine glycosides): Rutin (rhamnose-glucose) and sophoridine (glucose-glucose) are both disaccharides. The human small intestinal mucosa possesses only enzymes (such as lactase and sucrase) that break down specific types of glycosidic bonds (such as α-glucosidic bonds), but lacks enzymes that break down these specific β-glycosidic bonds on flavonoids. Therefore, intact flavonoid rutin glycosides or sophoridine glycosides cannot be broken down, resulting in lower colonic absorption efficiency than the small intestine, and a high dependence on individual gut microbiota composition (explaining why individuals react so differently to rutin and other rutin glycoside flavonoids).

[0024] In simple terms: flavonoids bound to glucosides are absorbed faster and more directly; while flavonoids bound to rutin (or other sophorosides) are absorbed more slowly, needing to reach the large intestine for processing by gut microbiota first. Differences in human gut microbiota determine the significant differences in effects among different individuals. Flavonoid aglycones (alcohol-soluble flavonoids) are not bound to glycosides, are insoluble in water, and have a low absorption rate by the body.

[0025] During the growth process, plant flavonoids undergo a continuous process of glycosylation, which alters their water solubility. Glycosylated flavonoids are more easily dissolved in water and absorbed by the body. This is the essence of why traditional Chinese medicine requires long-term growth to accumulate the essence of nature. Insoluble flavonoids cannot dissolve during the decoction process, while glycosylated flavonoids are dissolved in water and extracted by the body through decoction, thus being absorbed and exerting their effects.

[0026] Rutin tablets are a type of vitamin P, a dehydroflavonoid glycoside. It is a quercetin-rutin glycoside, often found alongside vitamin C in food. It can maintain vascular elasticity, enhance capillary resistance, reduce capillary fragility and permeability, promote cell proliferation, and prevent blood cell aggregation. It also has anti-inflammatory and anti-allergic effects. It is almost insoluble in water and poorly soluble in fat.

[0027] At room temperature (10℃), rutin has a solubility of 8.5 mg / 100 ml, which is considered sparingly soluble (below 0.01 g). When heated, such as above 30℃, it becomes slightly soluble (10 mg - 100 mg).

[0028] Human digestive organs are characterized by water solubility and fat solubility, while flavonoids are alcohol solubility and unrelated to these properties, so water solubility is particularly important for detection.

[0029] The present invention has the following advantages: (1) In the extraction of flavonoid glycosides in this invention, the flavonoid raw materials and water are first added to the extraction tank according to the set ratio and soaked for half an hour to make the flavonoid glycosides dissolve more thoroughly. The ratio of water to plant raw materials has a direct impact on the dissolution efficiency of flavonoid glycosides. If the water ratio is too small, although the dissolution concentration of flavonoid glycosides is increased, the total amount of flavonoid glycosides is not completely dissolved, resulting in serious waste; while if the water volume is increased, the total amount of flavonoid glycosides is dissolved more thoroughly, but the concentration of flavonoid glycosides is diluted too much, and the efficiency of concentration increase is affected. This invention achieves efficient dissolution of flavonoid glycosides by setting the mass ratio of flavonoid raw materials and water to 1:(7-10).

[0030] (2) The present invention increases the dissolution rate of flavonoid glycosides by adjusting the soaking temperature beforehand. If the soaking process is not properly controlled by temperature, the dissolution of flavonoid glycosides will be affected, and the extraction rate of flavonoid glycosides will be significantly reduced. If the soaking temperature is not properly controlled, flavonoid glycosides will hydrolyze into water-insoluble aglycones in a high-temperature environment, thereby reducing the extraction rate of flavonoid glycosides. Data shows that buckwheat flavonoids and sea buckthorn flavonoids have limited high-temperature tolerance. At 90°C, 15% of flavonoid glycosides will dissolve within 5 to 10 minutes, causing the glycoside flavonoids to be converted into aglycones. The present invention sets heating, cooling, and holding temperatures and corresponding times during the soaking process, which can accelerate the dissolution of flavonoid glycosides.

[0031] (3) In this invention, when testing the flavonoid content of raw materials and excipients, the alcohol dissolution method is not used. Instead, the flavonoid hydrolysis process is simulated by heating. Boiling water is added to the beaker containing the raw materials and excipients to be tested, and the temperature is kept constant at 85-88℃ for 30 minutes to maximize the amount of flavonoid glycosides dissolved by hydrolysis, so that the measured flavonoid glycoside content of the raw materials and excipients is close to the actual situation. The calculation method of the working curve or regression equation is the same as that of GB19777-2013, which is convenient for comparison with other measurement methods.

[0032] (4) In preparing a flavonoid-rich beverage, the present invention also sterilizes and preserves the plant flavonoid glycoside extract, making the flavonoid-rich beverage suitable for food processing. At the same time, after sterilization, the temperature of the plant flavonoid glycoside extract drops rapidly to prevent the flavonoid glycosides from being converted into flavonoid aglycones at high temperatures. Attached Figure Description

[0033] Figure 1 A flowchart illustrating a method for extracting flavonoid glycosides and a method for preparing a beverage rich in flavonoid glycosides; Figure 2 A diagram showing the temperature and time control of soaking plant raw materials for a method of extracting flavonoids and a method of preparing flavonoid-rich beverages; Figure 3 This is a temperature and time control diagram for sterilization of plant flavonoid extract, used in a method for extracting flavonoid glycosides and preparing beverages rich in flavonoid glycosides. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0035] Example 1 like Figure 1 As shown, a method for extracting flavonoid glycosides and a method for preparing a beverage rich in flavonoid glycosides include the following steps: S1. Place 80kg of buckwheat hulls, 20kg of buckwheat bran, 30kg of kudzu root, and 1000kg of water in an extraction tank and soak for 30 minutes. The flavonoid content of buckwheat hulls, buckwheat bran, and kudzu root was determined by the water-soluble flavonoid content measurement method of the present invention. Among them, the buckwheat hulls were black buckwheat hulls, and the flavonoid content of buckwheat hulls was 12 mg / mL, the flavonoid content of buckwheat bran was 35 mg / mL, and the flavonoid content of kudzu root was 8.9 mg / mL. S2. Raise the temperature in the extraction tank to 86°C for 40 minutes, then lower it to 50°C for 32 minutes. After cooling, keep the temperature at 50°C and soak for 120 minutes to obtain the first solid-liquid mixture. S3: Perform a first round of extraction on the first solid-liquid mixture, which includes three extractions; During the three extractions, the temperature in the extraction tank was raised to 86℃ for 40 minutes, then cooled to 50℃ for 32 minutes. After cooling, the solution was kept at 50℃ for 120 minutes. The extract was then transferred to the first extract storage tank, where the flavonoid content was 0.96 mg / mL. 1000 kg of water was added to the extraction tank for the second extraction, and the extract was transferred to the second extract storage tank. After the second extraction, 1000 kg of water was added to the extraction tank for the third extraction, and the extract was transferred to the third extract storage tank. S4: Empty the extraction tank, add the liquid from the three extraction storage tanks in the corresponding rounds to the extraction tank, add water until the liquid weight is 1000kg, then add 80kg of buckwheat hulls, 20kg of buckwheat bran and 30kg of kudzu root to carry out the second round of extraction. The second round of extraction includes three extractions. The temperature, heating time, cooling time, and holding time after cooling are the same as in step S3 for each extraction. After the first extraction, the extract is transferred to the first extract storage tank. The flavonoid content in the solution in the first extract storage tank is 1.54 mg / mL. During the second extraction, the extract from the second extract storage tank is added to the extraction tank, and water is added until the liquid weight is 1000 kg. After the second extraction, the extract is transferred to the second extract storage tank. During the third extraction, the extract in the third extract storage tank is added to the extraction tank, and water is added until the liquid weight is 1000 kg. After the third extraction, the extract is transferred to the third extract storage tank. S5: Empty the extraction tank, add the liquid from the three extraction storage tanks in the corresponding rounds to the extraction tank in sequence, add water until the liquid weight is 1000kg, then add 80kg of buckwheat hulls, 20kg of buckwheat bran and 30kg of kudzu root, and carry out the third round of extraction. The method of the third round of extraction is the same as that of the second round of extraction. After the third extraction, the flavonoid content in the first extract storage tank was 2 mg / mL, and it was used as the final product for the next process. The solutions from the second and third extract storage tanks were used as raw materials for the next batch of extraction.

[0036] S6. The flavonoid glycoside extract was filtered using a diatomaceous earth filter to obtain a plant flavonoid glycoside extract. The ratio of coarse earth to fine earth was 50% each. S7. The plant flavonoid glycoside extract is bottled to obtain bottled flavonoid glycoside extract; S8. Sterilize the flavonoid glycoside extract. Rapidly raise the temperature from room temperature to 87 degrees Celsius within 40 minutes and maintain this temperature for 30 minutes. After sterilization, open the sterilizer door and rapidly cool the solution to below 50 degrees Celsius for 30-32 minutes.

[0037] S9. Prepare 12% sweetener in a reusable container and fill it into small bottles to obtain a flavonoid-rich drink with a flavonoid content of 1.76 mg / ml.

[0038] Example 2 like Figure 1 As shown, a method for extracting flavonoids and a method for preparing a flavonoid-rich beverage include the following steps: 20% sea buckthorn pulp + 80% buckwheat hulls + 30% wolfberry fruit; S1. Place 20kg of sea buckthorn pulp, 80kg of buckwheat hulls, 30kg of dried goji berries, and 1000kg of water in an extraction tank and soak for 30 minutes. The flavonoid content of buckwheat hulls, buckwheat bran, and dried wolfberries was determined by the water-soluble flavonoid content measurement method of the present invention. The flavonoid content of sea buckthorn pulp was 1.6 mg / mL, the flavonoid content of buckwheat hulls was 12 mg / mL, and the flavonoid content of dried wolfberries was 6.6 mg / mL. S2. Raise the temperature in the extraction tank to 86°C for 35 minutes, then lower it to 50°C for 30 minutes. After cooling, keep the temperature at 50°C and soak for 120 minutes to obtain the first solid-liquid mixture. S3: Perform a first round of extraction on the first solid-liquid mixture, which includes three extractions; During the three extractions, the temperature in the extraction tank was raised to 86℃ for 35 minutes, then cooled to 50℃ for 30 minutes. After cooling, the solution was kept at 50℃ for 120 minutes. The extract was then transferred to the first extract storage tank, where the flavonoid content was 0.59 mg / mL. 1000 kg of water was added to the extraction tank for the second extraction, and the extract was transferred to the second extract storage tank. After the second extraction, 1000 kg of water was added to the extraction tank for the third extraction, and the extract was transferred to the third extract storage tank. S4: Empty the extraction tank and add the three concentrations of extract to the corresponding extraction storage tanks for each round. Then add 20 kg of sea buckthorn pulp, 80 kg of buckwheat hulls, and 30 kg of wolfberry fruit for the second round of three extractions. The temperature, heating time, cooling time, and holding time after cooling are the same as in step S3 for each extraction. After the first extraction, transfer the extract to the first extract storage tank. During the second extraction, the extract from the second extract storage tank is added to the extraction tank, and water is added until the liquid weight is 1000 kg. After the second extraction, the extract is transferred to the second extract storage tank. During the third extraction, the extract in the third extract storage tank is added to the extraction tank, and water is added until the liquid weight is 1000 kg. After the third extraction, the extract is transferred to the third extract storage tank. S5: Empty the extraction tank, add the three concentrations of extract to the corresponding extraction tanks, add water until the liquid weight is 1000kg, add 20kg of sea buckthorn pulp, 80kg of buckwheat hulls and 30kg of wolfberry fruit, and carry out the third round of three extractions. After the third extraction, the flavonoid content in the first extract storage tank was 1.2 mg / mL, which was then used as the final product for the next process. The solutions from the second and third extract storage tanks were used as raw materials for the next batch of extraction.

[0039] S6. The flavonoid glycoside extract was filtered using a diatomaceous earth filter to obtain a plant flavonoid glycoside extract. The ratio of coarse earth to fine earth was 50% each. S7. The plant flavonoid glycoside extract is bottled to obtain bottled flavonoid glycoside extract; S8. Sterilize the flavonoid glycoside extract. Rapidly raise the temperature from room temperature to 85 degrees Celsius within 42 minutes and maintain this temperature for 30 minutes. After sterilization, open the sterilizer door and rapidly cool the solution to below 50 degrees Celsius for 30 minutes.

[0040] S9. Prepare 12% sweetener in a reusable container and fill it into small bottles to obtain a flavonoid-rich drink with a flavonoid content of 1.05 mg / ml.

[0041] Example 3 like Figure 1 As shown, a method for extracting flavonoid glycosides and a method for preparing a beverage rich in flavonoid glycosides include the following steps: S1. Place 30kg of dried hawthorn, 80kg of buckwheat hulls, 20kg of kudzu root, and 1000kg of water in an extraction tank and soak for 30 minutes. The flavonoid content of buckwheat hulls, buckwheat bran, and kudzu root was determined by the water-soluble flavonoid content measurement method of the present invention. The flavonoid content of dried hawthorn was 22.4 mg / mL, the flavonoid content of buckwheat hulls was 12 mg / mL, and the flavonoid content of kudzu root was 8.9 mg / mL. S2. Raise the temperature in the extraction tank to 86°C for 35 minutes, then lower it to 50°C for 30 minutes. After cooling, keep the temperature at 50°C and soak for 120 minutes to obtain the first solid-liquid mixture. S3: The first solid-liquid mixture is subjected to the first round of extraction, which includes three extractions. During the three extractions, the temperature in the extraction tank is raised to 86°C for 35 minutes, then cooled to 50°C for 30 minutes. After cooling, the mixture is kept at 50°C for 120 minutes. The three extracts are then transferred to the first extract storage tank, the second extract storage tank, and the third extract storage tank, respectively. The flavonoid content in the solution in the first extract storage tank is 0.9 mg / mL. S4: Empty the extraction tank and add the three concentrations of extract to the corresponding extraction storage tanks for each round. Then add 30 kg of dried hawthorn, 80 kg of buckwheat hulls, and 20 kg of kudzu root for the second round of three extractions. The temperature, heating time, cooling time, and holding time after cooling are the same as in step S3 for each extraction. After the first extraction, transfer the extract to the first extract storage tank. During the second extraction, the extract from the second extract storage tank is added to the extraction tank, and water is added until the liquid weight is 1000 kg. After the second extraction, the extract is transferred to the second extract storage tank. During the third extraction, the extract in the third extract storage tank is added to the extraction tank, and water is added until the liquid weight is 1000 kg. After the third extraction, the extract is transferred to the third extract storage tank. S5: Empty the extraction tank, add the liquid from the three extraction storage tanks to the corresponding extraction tank, add water until the liquid weight is 1000kg, then add 30kg of dried hawthorn, 80kg of buckwheat hulls and 20kg of kudzu root, and carry out the third round of extraction. The flavonoid content in the first extract storage tank solution of the third round of extraction was 1.89 mg / mL, and it was used as the formal product for the next process. The solutions from the second and third extract storage tanks were used as preparation materials for the next batch of extraction process.

[0042] S6. The flavonoid glycoside extract was filtered using a diatomaceous earth filter to obtain a plant flavonoid glycoside extract. The ratio of coarse earth to fine earth was 50% each. S7. The plant flavonoid glycoside extract is bottled to obtain bottled flavonoid glycoside extract; S8. Sterilize the flavonoid glycoside extract. Rapidly raise the temperature from room temperature to 85 degrees Celsius within 40 minutes and maintain this temperature for 30 minutes. After sterilization, open the sterilizer door and rapidly cool the solution to below 50 degrees Celsius for 30 minutes.

[0043] S9. Prepare 12% sweetener in a reusable container and fill it into small bottles to obtain a flavonoid-rich drink with a flavonoid content of 1.66 mg / mL.

[0044] Example 4 like Figure 1 As shown, a method for extracting flavonoid glycosides and a method for preparing a beverage rich in flavonoid glycosides include the following steps: S1. Place 100kg of dried Sophora japonica flowers and 1000kg of water in an extraction tank and soak for 30 minutes. The flavonoid content of dried Sophora japonica flowers was determined by the water-soluble flavonoid glycoside measurement method of the present invention, wherein the flavonoid glycoside content of dried Sophora japonica flowers was 17 mg / g; S2. Raise the temperature in the extraction tank to 86°C for 35 minutes, then lower it to 50°C for 30 minutes. After cooling, keep the temperature at 50°C and soak for 120 minutes to obtain the first solid-liquid mixture. S3: Perform a first round of extraction on the first solid-liquid mixture, which includes three extractions; During the three extractions, the temperature in the extraction tank was raised to 86℃ for 35 minutes, then cooled to 50℃ for 30 minutes. After cooling, the solution was kept at 50℃ for 120 minutes. The extracts were then transferred to the first, second, and third extraction tanks, respectively. The flavonoid content in the solution in the first extraction tank was 0.93 mg / mL. S4: Empty the extraction tank, add the three concentrations of extract to the corresponding extraction tanks, add water until the liquid weight is 1000kg, and then add 100kg of dried Sophora japonica flowers for the second round of extraction, using the same method as step S3. S5: Empty the extraction tank, add the three concentrations of extract to the corresponding extraction tanks, add water until the liquid weight is 1000kg, and then add 100kg of dried Sophora japonica flowers for the third round of extraction. The flavonoid content in the first extract storage tank solution of the third round of extraction was 1.92 mg / mL, and it was used as the formal product for the next process. The solutions from the second and third extract storage tanks were used as preparation materials for the next batch of extraction process.

[0045] S6. The flavonoid glycoside extract was filtered using a diatomaceous earth filter to obtain a plant flavonoid glycoside extract. The ratio of coarse earth to fine earth was 50% each. S7. The plant flavonoid glycoside extract is bottled to obtain bottled flavonoid glycoside extract; S8. Sterilize the flavonoid glycoside extract. Rapidly raise the temperature from room temperature to 85 degrees Celsius within 40 minutes and maintain this temperature for 30 minutes. After sterilization, open the sterilizer door and rapidly cool the solution to below 50 degrees Celsius for 30 minutes.

[0046] S9. Prepare 12% sweetener in a reusable container and fill it into small bottles to obtain a flavonoid-rich drink with a flavonoid content of 1.69 mg / ml.

[0047] In this embodiment, the content of Sophora japonica flowers is affected by many factors such as variety, harvesting time (bud / full bloom), and detection method, resulting in significant differences. Due to the lack of direct measurement data, the following estimation is based on comparative data of its isomers.

[0048] According to a study, the average content of kaempferol-3-O-rutin in 40 batches of Sophora japonica flowers was about 10%, while the content of isoquercitrin was usually much lower, with one study measuring a content of 1.693 mg / g.

[0049] Additional notes: Rutin and kaempferol-3-O-rutin are the absolute main components of Sophora japonica flowers, with a total content of over 20%; while the content of quercetin-3-O-glucoside (isoquercetin) and other quercetin monosaccharide glycosides (such as glucoside and galactoside) is generally very low.

[0050] The following is a quantitative analysis of the proportion of major flavonoid components in Sophora japonica flowers, based on data from the Chinese Pharmacopoeia and multiple academic papers: 1. Two major "absolute principal components" (accounting for more than 20%) Rutin and kaempferol-3-O-rutin are indeed the two most abundant components, and their combined content usually reaches more than 20%.

[0051] Rutin: It has the highest content, accounting for about 6%-10% in Sophora japonica flowers (open flowers) and up to 15%-20% in Sophora japonica buds (flower buds).

[0052] Kaempferol-3-O-rutin: Its content is second only to rutin, accounting for about 4%-10%. Some literature reports that its content is even comparable to or slightly higher than that of rutin (e.g., 10.08%).

[0053] 2. Content of quercetin monosaccharides Isoquercetin (quercetin-3-O-glucoside): Content data: It typically accounts for only 0.2%-0.5% (or even lower) in Sophora japonica flowers. Although it is an important active ingredient, it is far from being the main component in Sophora japonica flower raw materials.

[0054] Hyperoside (quercetin-3-O-galactoside): Content data: Although the academic community generally believes that its content is lower than that of rutin, in some studies, hyperoside is one of the main components besides rutin and kaempferol-3-O-rutin, accounting for about 0.5%-2%, which is significantly higher than that of isoquercitrin. Therefore, if it is said that "all quercetin monosaccharides have very low content", hyperoside is a significant exception.

[0055] In addition to the components mentioned above, locust flowers also contain: Quercetin (aglycone): present in very low amounts (usually <0.1%), mainly produced by the degradation of rutin.

[0056] Narcisin (isorhamnoside-3-O-rutin): approximately 0.1%-0.5%.

[0057] The content of rutin in Sophora japonica flowers is ranked as follows: rutin ≈ kaempferol-3-O-rutin (total >20%) > hyperoside > quercetin / isoquercetin / narcissin.

[0058] Isoquercitrin (quercetin-3-O-glucoside), hyperoside (quercetin-3-O-galactoside), rutin, and kaempferol-3-O-rutin glycoside. The core principle in comparing these four compounds lies in the fact that the type and number of sugar groups determine their absorption efficiency. Simply put: monosaccharides (especially glucosides) are absorbed best, while disaccharides (rutin glycosides) are absorbed very poorly.

[0059] Water solubility comparison: The differences in water solubility are significant. The water solubility of rutin and kaempferol-3-O-rutin glycoside is much different from that of isoquercitrin (glucoside) and hyperoside (galactoside).

[0060] All four compounds, due to the attachment of hydrophilic glycosides, have much higher water solubility than the almost insoluble quercetin aglycone. Among them: Isoquercetin (glucoside) and hyperoside (galactoside): have the best and similar water solubility. Their small monosaccharide molecules effectively increase polarity.

[0061] Rutin and kaempferol-3-O-rutin: Relatively low water solubility (almost insoluble in cold water). They are linked to a larger disaccharide (rutin), and steric hindrance may slightly reduce their solubility.

[0062] Comparison of absorption and bioavailability: Huge differences The key difference lies in whether it can be directly absorbed by the small intestine:

[0063] Summarize the composition of Sophora japonica flowers in order of ranking Water solubility: Isoquercetin ≈ Hyperoside > Rutin ≈ Kaempferol-3-O-rutin Bioavailability: Isoquercetin > Hyperoside >> Rutin ≈ Kaempferol-3-O-rutin Modern technology extracts and produces rutin tablets, which are composed of two main flavonoids: rutin and kaempferol-3-O-rutin. These two components have extremely poor water solubility. Rutin can only be passively absorbed by the large intestine through enzymatic hydrolysis of rutin by intestinal bacteria. This results in a very low utilization rate of the drug by the human body, thus limiting its efficacy.

[0064] In addition to the flavonoids rutin and kaempferol-3-O-rutin, Sophora japonica flowers also contain certain amounts of isoquercitrin and hyperoside. These two flavonoid components contain monoglucoside and monogalactoside, respectively. The water solubility of these components is significantly improved, and they are rapidly absorbed into small intestinal cells via SGLT1 after enzymatic hydrolysis in the human small intestine, resulting in the highest bioavailability. Crucially, these two flavonoids meet the technical characteristics of this invention and can be effectively enriched using this technology, as shown in the table below.

[0065]

[0066] Therefore, the present invention enriches isoquercitrin, which is easily soluble in water and has high bioavailability, slightly higher hyperoside, and extremely low narcissin (isorhamnoside-3-O-rutin).

[0067] The comparative detection data of flavonoid glycoside measurement methods are shown in the table below:

[0068] The solid flavonoid content measured by the alcohol-soluble method in GB / T20574-2006 is much higher than the measurement results of the water-soluble flavonoid glycoside measurement method of this invention. GB / T20574-2006 not only detects water-soluble flavonoid glycosides, but also alcohol-soluble flavonoid glycosides.

[0069] The ratio of water to plant flavonoids during extraction determines the efficiency of flavonoid glycoside dissolution. If the water ratio is reduced, for example, by 10 times, the concentration of flavonoid glycosides dissolved increases, but the total amount of flavonoid glycosides dissolved is not completely removed, resulting in significant waste. On the other hand, if the water volume is increased, for example, by 30 times, the total amount of flavonoid glycosides dissolved more completely, but the concentration of flavonoid glycosides is diluted too much, affecting the efficiency of concentration improvement.

[0070] like Figure 2 As shown in the soaking temperature curve, the extraction of flavonoid glycosides follows a general pattern. Without proper temperature control during the extraction process, the dissolution of flavonoid glycosides is affected, leading to a significant decrease in the extraction rate. Furthermore, improper temperature control can cause flavonoid glycosides to hydrolyze into water-insoluble aglycones at high temperatures, further reducing the extraction rate. Buckwheat flavonoids and sea buckthorn flavonoids have limited high-temperature tolerance; at 90 degrees Celsius, approximately 15% of the flavonoid glycosides dissolve within 5–10 minutes, transforming into aglycones.

[0071] like Figure 3 As shown, sterilization and preservation of plant flavonoid glycoside extracts is an indispensable step in food processing. However, if the high temperature cannot be reduced quickly after sterilization, the flavonoid glycosides will undergo high-temperature hydrolysis and dissolve, converting into flavonoid aglycones, which greatly reduces the efficacy of the flavonoid glycoside extract.

[0072] Comparative Example 1 In Example 3, during the sterilization of the buckwheat flavonoid glycoside extract, the temperature was not cooled to 50 degrees Celsius in time after the high-temperature sterilization was completed. Instead, it was slowly cooled with the furnace. This cooling caused the flavonoid glycoside content of the 186 mg / 100 ml solution to decrease to 130 mg / 100 ml after three days of cooling with the furnace, a decrease rate of 31.5%, resulting in a serious loss of flavonoid glycosides.

[0073] The results of flavonoid content measurements before and after sterilization in multiple batches are shown in the table below:

[0074] The results above show that the flavonoid content of directly prepared products without sterilization is close to that of diluted products. Therefore, this method will not cause flavonoid glycosylation attenuation, but it is not suitable for industrial production.

[0075] After sterilization, the product is allowed to cool to room temperature and then stored for another 3 months. This method results in a significant decrease in flavonoid glycosylation and a sharp drop in the levels of flavonoids.

[0076] The sterilization control parameters (following step S8) are maintained for 3 months. Controlling the sterilization parameters can effectively control the hydrolysis of flavonoid glycosylation, with the optimal flavonoid attenuation controlled to within 10%.

[0077] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for extracting flavonoid glycosides, characterized in that: Includes the following steps: S1. Place the plant raw materials or plant mixture raw materials and water in an extraction tank at a mass ratio of 1:(7.5~10) and soak for 20~40 minutes; The flavonoid content of the plant raw materials or plant mixture raw materials was detected by water-soluble flavonoid glycoside measurement method during material selection and on-site testing. S2. Raise the temperature in the extraction tank to 85-88°C for 35-40 minutes, then lower the temperature to 48-50°C for 30-32 minutes. After cooling, maintain the temperature at 48-50°C for 120-125 minutes to obtain the first solid-liquid mixture. S3: Perform a first round of extraction on the first solid-liquid mixture. The first round of extraction includes three extractions. The temperature, heating time, cooling time and holding time after cooling are the same as in step S2 for each extraction. After the first extraction, the extract is transferred to the first extract storage tank. During the second extraction, the same weight of water as in step S1 is added to the extraction tank and the extraction method is the same as the first extraction. The extract is then transferred to the second extract storage tank. During the third extraction, the same weight of water as in step S1 is added to the extraction tank and the extraction method is the same as the first extraction. The extract is then transferred to the third extract storage tank. S4: Empty the extraction tank and perform the second round of extraction. The second round of extraction also includes three extractions. The temperature, heating time, cooling time and holding time after cooling are the same as in step S2 for each extraction. Add the same weight of plant raw material or plant mixture raw material as in step S1 and the extract in the first extract tank to the extraction tank and add water to make the weight of the liquid in the extraction tank the same as the weight of the water in step S1. Then perform the first extraction in the second round. After extraction, transfer the extract to the first extract tank. During the second extraction, the extract in the second extract tank is added to the extraction tank and water is added to make the weight of the liquid in the extraction tank the same as the weight of the water in step S1 before extraction is performed. After extraction, the extract is transferred to the second extract tank. During the third extraction, the extract in the third extract storage tank is added to the extraction tank and water is added to make the weight of the liquid in the extraction tank the same as the weight of the water in step S1 before extraction is performed. After extraction, the extract is transferred to the third extract storage tank. S5: Empty the extraction tank and proceed with the third extraction. The method for the third extraction is the same as that for the second extraction. After the third extraction, the liquid in the first extraction tank is the flavonoid extract. The liquid in the second and third extraction tanks is reserved for the next extraction of flavonoids.

2. The method for extracting flavonoid glycosides according to claim 1, characterized in that: In step S1, the method for measuring water-soluble flavonoid glycosides includes the following steps: SⅠ. Preparation of the test solution: Weigh 30g of the raw and auxiliary materials to be tested into a 500ml beaker using a balance, add 300ml of boiling water and weigh to obtain the weight, heat the beaker and keep it at a constant temperature of 85-88℃ for 30min, then add water to the weighed weight, cool and filter to obtain the test solution. Take 5.00g of the test solution into a 100ml beaker, adjust the pH to 7.1-7.2 with sodium hydroxide solution (10g / L), transfer it into a 100ml volumetric flask, dilute to the mark with water, and shake well to obtain the sample solution; SⅡ, The total flavonoid content, calculated as rutin, of the sample solution was measured using ultraviolet-visible spectrophotometry.

3. The method for extracting flavonoid glycosides according to claim 2, characterized in that: Step SⅡ includes the following steps: SⅡ-1. Pipette 0.00 mL, 0.50 mL, 1.00 mL, 2.00 mL, 3.00 mL, and 4.00 mL of rutin standard working solution, equivalent to 0.00 mg, 0.10 mg, 0.20 mg, 0.40 mg, 0.60 mg, and 0.80 mg of anhydrous rutin, respectively, into 25 mL stoppered colorimetric tubes. Add water to a final volume of 10 mL, add 1.0 mL of sodium nitrite solution, mix well, and let stand for 6 min. Then add 1.0 mL of aluminum nitrate solution, mix well, and let stand for 6 min. Next, add 4.0 mL of sodium hydroxide solution, add water to the mark, mix well, and let stand for 15 min. Using a 1 cm cuvette, adjust the zero point with a reagent blank, and measure the absorbance at a wavelength of 510 nm. Plot a working curve or calculate a regression equation with absorbance as the ordinate and the mass of rutin as the abscissa. SⅡ-2. Preheat the spectrophotometer 20 minutes in advance. Pipette 2.00 mL of the sample solution into two 25 mL stoppered colorimetric tubes, add water to 10 mL, add 1.0 mL of sodium nitrite solution to both tubes and mix well, then let stand for 6 minutes. Do not add 1.0 mL of aluminum nitrate solution to one tube to make a sample blank, mix well and let stand for 6 minutes. Add 4.0 mL of sodium hydroxide solution to both tubes, then add water to the mark and mix well, let stand for 15 minutes. Adjust the zero point with a 1 cm cuvette using the reagent blank, and measure the absorbance at a wavelength of 510 nm. Measure the absorbance of the test solution and subtract the absorbance of the sample blank. Find the mass m1 of total flavonoids in the sample solution from the working curve or calculate it using the regression equation. Total flavonoid content in the sample (calculated as rutin): ； in: X represents the total flavonoid content in the raw material sample to be tested, calculated as rutin, in milligrams per 100 grams. m1 is the total flavonoids in the test solution, expressed as rutin, which is determined by the working curve or calculated by the regression equation, and is expressed in milligrams. m represents the mass of the raw material sample to be tested, in grams (g).

4. The method for extracting flavonoid glycosides according to claim 3, characterized in that: In step S1, the concentration of the sodium hydroxide solution is 10 g / L; In step S2, the concentration of sodium nitrite solution is 50 g / L, the concentration of aluminum nitrate solution is 100 g / L, and the concentration of sodium hydroxide solution is 200 g / L. The concentration of the rutin standard solution used is 0.20 mg / mL, which is obtained by pipetting 10.00 mL of the rutin standard stock solution into a 100 mL volumetric flask and diluting it to the mark with water. The concentration of the rutin standard stock solution is 2.00 mg / mL. The preparation method is as follows: Weigh 0.2000 g of anhydrous rutin that has been dried to constant weight under reduced pressure at 120℃ and place it in a 100 mL volumetric flask. Dissolve it in ethanol solution and dilute to the mark. Shake well to obtain the solution. The anhydrous rutin is rutin or rutin with a mass fraction greater than 95%, and the volume fraction of the ethanol solution is 60%.

5. The method for extracting flavonoid glycosides according to claim 2, characterized in that: The plant material or plant mixture can be solid or liquid; In steps S2 to S5, the method for measuring flavonoid glycosides in the liquid in the extraction storage tank and the flavonoid glycoside extract is as follows: Step S1 is to weigh 5.00 g of the mixed sample into a 100 mL beaker, adjust the pH value to 7.1-7.2 with sodium hydroxide solution, transfer it into a 100 mL volumetric flask, dilute to the mark with water, and shake well. Step S2 is the same as the method for measuring water-soluble flavonoid glycosides.

6. The method for extracting flavonoid glycosides according to claim 1, characterized in that: In step S1, the plants in the plant raw materials or plant mixture raw materials include any one or more of the following: buckwheat bran, buckwheat hulls, kudzu root, sea buckthorn pulp, dried hawthorn, wolfberry fruit, and sophora japonica flowers; After step S5, the liquid in the second extract storage tank and the third extract tank is added to the first extraction tank and the second extraction tank of the first extraction in the next extraction of flavonoid glycosides, respectively. When the weight of the extract is less than that of the water in step S1, water is added.

7. The method for extracting flavonoid glycosides according to claim 6, characterized in that: The plant mixture is made from a mixture of buckwheat hulls, buckwheat bran, and kudzu root, or from a mixture of sea buckthorn pulp, buckwheat hulls, and wolfberry fruit, or from a mixture of dried hawthorn, buckwheat hulls, and kudzu root. The plant material is Sophora japonica flowers.

8. The method for extracting flavonoid glycosides according to claim 7, characterized in that: When the raw material of the plant mixture is a mixture of buckwheat hulls, buckwheat bran and kudzu root, the mass ratio is (7-9):(1-3):(2-4); When the raw material of the plant mixture is a mixture of sea buckthorn pulp, buckwheat hulls and wolfberry fruit, the mass ratio is (1-3):(7-9):(2-4); When the raw material of the plant mixture is a mixture of dried hawthorn, buckwheat hulls and kudzu root, the mass ratio is (2-4): (7-9): (1-3).

9. A method for preparing a flavonoid-rich beverage according to any one of claims 1 to 8, characterized in that: It also includes the following steps: S6. The flavonoid glycoside extract is filtered using a diatomaceous earth filter to obtain a plant flavonoid glycoside extract. S7. The flavonoid glycoside extract is filled into a transfer container to obtain a filled flavonoid glycoside extract; S8. Sterilize the flavonoid glycoside extract by raising the temperature from room temperature to 85-87 degrees Celsius within 40-42 minutes and maintaining it for 30-32 minutes. After sterilization, open the sterilization cabinet door and quickly cool it to below 50 degrees Celsius for 30-32 minutes.

10. The method for preparing a flavonoid-rich beverage according to claim 9, characterized in that: In step S6, the fine and coarse diatomaceous earth in the diatomaceous earth filter are of the same quality. In step S7, 25KG reusable containers are used for filling; In step S8, the sterilization process is as follows: the temperature is raised from room temperature to 85-87°C within 40-42 minutes, maintained for 30-32 minutes, sterilization is completed, the sterilization cabinet door is opened, and the temperature is cooled to below 50°C for 30-32 minutes. It also includes step S9: S9. Prepare 10-14% sweetener in a transfer pot and fill the flavonoid glycosides into small bottles to obtain the flavonoid glycoside-rich beverage. The sweetener includes honey and / or white sugar and / or monk fruit juice.

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