Tartary buckwheat sprout general flavone extract and application thereof in formula milk powder

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a tartary buckwheat sprout general flavone extract and application thereof in formula milk powder. The preparation method comprises the following steps: adding tartary buckwheat sprout powder into a deep-eutectic solvent, grinding, centrifuging, taking supernate, diluting with water or concentrating to obtain a tartary buckwheat sprout general flavone solution serving as a core material, uniformly dispersing the core material into a wall material solution, and carrying out spray drying treatment to obtain tartary buckwheat sprout general flavone powder. The method is green, safe and simple to operate, and the extraction efficiency of the flavonoid compounds can be improved; by using the eutectic solvent, the problems of poor solubility, instability, low bioavailability and the like of flavonoid compounds are solved, and the problem of degradation of heat-sensitive components caused by high temperature in the spray drying process is solved. The obtained general flavone powder is applied to the formula milk powder, and the formula milk powder with the blood sugar reducing effect is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to a tartary buckwheat sprout total flavonoid extract and application of the extract in formula milk powder. Background Art

[0002] Flavonoids have multiple physiological activities and pharmacological effects, including antioxidant, anti-tumor, anti-cancer, antibacterial, immunomodulatory, cardiovascular protection, and hypoglycemic effects. Studies have shown that flavonoids can inhibit carbohydrate digestion and glucose absorption, and regulate insulin secretion through multiple signaling pathways. Moreover, a diet rich in flavonoids is negatively correlated with the risk of diabetes. The risk of type 2 diabetes can be reduced by 19%, 26%, 28%, 19%, 26%, and 27% with a higher intake of anthocyanidins, flavan-3-ols, flavonols, flavonoids, polymers, and proanthocyanidins, respectively.

[0003] Buckwheat is a grain rich in flavonoid active substances. The flavonoid content (mainly rutin and quercetin) in buckwheat is 9 to 300 times higher than that in common buckwheat. Appropriate germination treatment of buckwheat seeds can increase the content of some flavonoid compounds. At present, the research on sprouted buckwheat mainly focuses on improving its nutritional components and increasing the content of functional substances through germination technology, while there are few reports on the extraction process of flavonoid compounds in buckwheat sprouts.

[0004] In the prior art, the extraction of flavonoids from sprouted buckwheat is mostly carried out by organic solvent extraction and ultrasound-assisted extraction. Using organic solvents for extraction not only increases costs, but also poses potential risks to the environment and human health. After extraction with organic solvents, it is usually necessary to further separate the extracted flavonoids, and this process will cause a certain amount of bioactive components to be lost.

[0005] In addition, flavonoids have the disadvantages of poor solubility and sensitivity to the external environment (such as light, temperature, pH and oxygen), which reduces their bioavailability. Microencapsulation of flavonoids can help solve the above problems, but the use of high temperatures in the process of preparing microcapsule powders by spray drying may induce thermal degradation, resulting in instability of heat-sensitive components and reducing the content of active ingredients in the powder.

[0006] The present invention provides a process for extracting total flavonoids from buckwheat sprouts by a low eutectic solvent-assisted mechanochemical method, in order to solve the problems of food safety, process loss, biological activity, stability, etc. existing in the flavonoid extraction process of the prior art. Summary of the invention

[0007] The first purpose of the present invention is to provide a new process for extracting total flavonoids from tartary buckwheat buds, which uses a low eutectic solvent-assisted mechanochemical method to extract total flavonoids from tartary buckwheat buds. This method is green, safe, and easy to operate, and can improve the extraction efficiency of flavonoid compounds.

[0008] The second purpose of the present invention is to solve the problems of poor solubility, instability and low bioavailability of flavonoids mentioned in the background technology, as well as the degradation of heat-sensitive components caused by high temperature during spray drying. Then, a low eutectic solvent containing total flavonoid extract is used as a core material, mixed with a wall material, and spray-dried, and the obtained powder is added to a formula milk powder to provide a formula milk powder with a blood sugar-lowering effect.

[0009] In order to solve the above technical problems, the technical route adopted by the present invention is as follows: One of the technical solutions provided by the present invention is a method for extracting total flavonoids from tartary buckwheat buds. The method uses tartary buckwheat buds as raw materials, adds tartary buckwheat bud powder into a low eutectic solvent, grinds the tartary buckwheat buds, centrifuges to obtain a supernatant, dilutes or concentrates the tartary buckwheat bud total flavonoids solution with water to obtain a core material, uniformly disperses the core material in a wall material solution, and spray-dries the tartary buckwheat bud total flavonoids powder; Furthermore, the deep eutectic solvent uses betaine as a hydrogen bond acceptor; Furthermore, in the deep eutectic solvent, betaine and different types of hydrogen bond donors are mixed in a molar ratio of 1:1 to 6; Furthermore, the hydrogen bond donor includes one or more of polyols, amino acids, and organic acids; Furthermore, the polyol includes one or more of xylitol, sorbitol, and glucose; Furthermore, the amino acids include one or more of L-lysine and L-proline; Furthermore, the organic acid includes one or more of citric acid and malic acid; Furthermore, the deep eutectic solvent also contains water, and the water accounts for 20% to 60% of the total weight of the deep eutectic solvent; Further, the components are mixed and heated and stirred until colorless and transparent to obtain a low eutectic solvent; preferably 70-100° C., heated and stirred for 2 h-8 h; Further, the tartary buckwheat bud powder is added to the low eutectic solvent, and after grinding, the supernatant is obtained by centrifugation, and then filtered with a 0.45 μm microporous filter membrane to obtain a filtrate; Furthermore, the solid-liquid ratio of the tartary buckwheat bud powder to the low eutectic solvent is 1: 1-60; Furthermore, the grinding is performed by ball milling, and the ball milling conditions are: a rotation speed of 100-400 rpm; a time of 10-120 min; Further, a tartary buckwheat bud total flavonoid solution diluted or concentrated to 10wt% to 40wt% is used as a core material; Furthermore, the weight ratio of the core material to the wall material is 1:1-5; Furthermore, the wall material is one or more of β-cyclodextrin, maltodextrin, gum arabic, dextran, chitosan, whey protein, and skim milk powder; Furthermore, the spray drying conditions are: inlet air temperature 100~180℃, outlet air temperature 70~90℃, high pressure pump pressure 8~25Mpa, and negative pressure in the tower -50~-300Pa.

[0010] Preferably, a method for extracting total flavonoids from tartary buckwheat sprouts is as follows: (1) Betaine, xylitol and citric acid were mixed in a molar ratio of 1:1:1, 40 wt % of water was added, and the mixture was stirred at 80 ° C for 6 h until it became colorless and transparent to obtain a low eutectic solvent; buckwheat bud powder was added to the prepared low eutectic solvent at a material-liquid ratio of 1:30, and the mixture was milled at a ball mill speed of 350 r / min for 60 min, followed by centrifugation to obtain the supernatant, which was filtered through a 0.45 μm microporous filter membrane to obtain a filtrate.

[0011] (2) The filtrate was concentrated to obtain a 35 wt% total flavonoids solution of buckwheat buds as the core material, and β-cyclodextrin and dextran were mixed in a mass ratio of 2:3 to obtain a wall material solution; the core material was then evenly dispersed in the wall material solution with a core-to-wall mass ratio of 1:4, and stirred at 60°C for 30 min; and the total flavonoids powder of buckwheat buds was obtained after spray drying. The spray drying conditions were: inlet air temperature of 150°C, outlet air temperature of 85°C, high-pressure pump pressure of 20 MPa, and negative pressure in the tower of -200 Pa.

[0012] The second technical solution provided by the present invention is the total flavonoids powder of tartary buckwheat sprouts obtained by the method described in the first technical solution.

[0013] The third technical solution provided by the present invention is the application of the total flavonoids powder of tartary buckwheat sprouts described in the second technical solution, especially in the preparation of blood sugar lowering products.

[0014] The fourth technical solution provided by the present invention is a blood sugar-lowering formula milk powder, which comprises the following components in parts by weight: 70-89 parts of milk solid composition, 0.5-15 parts of fat composition, 2-10 parts of dietary fiber composition, and 2-8 parts of total flavonoids powder of tartary buckwheat sprouts; Furthermore, the total flavonoids powder of tartary buckwheat sprouts is prepared by the method described in one of the technical solutions; Furthermore, the milk solid composition includes but is not limited to one or more of milk powder, bovine colostrum powder, desalted whey powder, and whey protein powder; Further, the fat composition includes, but is not limited to, one or more of vegetable fat powder, medium chain triglyceride, fish oil powder, plant sterol ester, docosahexaenoic acid oil powder, and arachidonic acid oil powder; Furthermore, the vegetable fat powder contains one or more of the following: rapeseed oil, corn oil, coconut oil, linseed oil, palm oil, low-erucic acid rapeseed oil, sunflower oil, high-oleic acid sunflower oil, and soybean oil; Furthermore, the dietary fiber composition includes, but is not limited to, one or more of fructooligosaccharides, inulin, polydextrose, resistant dextrin, isomaltooligosaccharides, maltooligosaccharides, galacto-oligosaccharides, and raffinose.

[0015] The formula milk powder also contains complex vitamins, and each 100g of the formula milk powder includes one or more of the following vitamin components: 300~800μg RE (calculated as retinol) vitamin A, 6.3~10μg vitamin D, 10~20mg α-TE (calculated as α-tocopherol) vitamin E, 0.8~1.3mg vitamin B6, 30~90mg vitamin C, and 200~450μg folic acid.

[0016] The formula milk powder also contains complex minerals, and each 100g of the formula milk powder includes one or more of the following amounts of minerals: 6-15mg iron, 300-680mg calcium, 3-5mg zinc, 14-24μg selenium, 30-90mg magnesium, 300-600μg copper, and 30-100μg manganese.

[0017] Furthermore, the specific sources and addition amounts of the vitamins and minerals are in compliance with the requirements of GB 14880-2012 standard.

[0018] Preferably, the hypoglycemic formula milk powder comprises the following ingredients: 76 parts of milk powder, 12 parts of whey protein powder, 0.25 parts of docosahexaenoic acid oil powder, 0.35 parts of arachidonic acid oil powder, 2 parts of galacto-oligosaccharide, 3 parts of raffinose, 6 parts of total flavonoids powder of tartary buckwheat buds; The formula milk powder also contains complex vitamins. Every 100g of formula milk powder contains 360μg RE (calculated as retinol) vitamin A, 6.56μg vitamin D, 13mg α-TE (calculated as α-tocopherol) vitamin E, and 75mg vitamin C.

[0019] The formula milk powder also contains complex minerals, with each 100g of formula milk powder containing 360mg calcium, 11mg iron, 3.5mg zinc and 20μg selenium.

[0020] Beneficial Effects 1. The present invention provides a technical method for extracting total flavonoids from tartary buckwheat buds, using a mechanochemical assisted method to destroy the cell wall of tartary buckwheat buds, and further reducing the particle size of fine powder, increasing the specific surface area, and then increasing the contact area between the deep eutectic solvent and the tartary buckwheat bud powder, which is conducive to the dissolution of flavonoid compounds. The ionic liquid in the deep eutectic solvent of the present invention can form hydrogen bonds or ionic bonds with flavonoid compounds, thereby improving the extraction efficiency of flavonoid compounds, and using the deep eutectic solvent to replace the traditional organic solvent has the advantages of low cost, simple preparation, green and non-toxic.

[0021] 2. The present invention uses a low eutectic solvent in which flavonoids are dissolved after extraction as a core material, which can not only reduce the process of separating flavonoids from the low eutectic solvent and then preparing total flavonoid powder or other forms of products, shorten the process time, but also reduce the loss of bioactive components during the separation process. In addition, the presence of a low eutectic solvent helps to improve the water solubility of flavonoids after spray drying. Under a simulated gastrointestinal environment, the total flavonoid powder of buckwheat buds prepared by extraction with a low eutectic solvent has a high bioacceptability rate, and the bioavailability of flavonoids is effectively improved. Therefore, the method of the present invention solves the problems of low solubility of flavonoids, sensitivity to the external environment, and low bioavailability.

[0022] 3. The low eutectic solvent used in the present invention is not only an extractant but also a protective agent, which can provide a milder internal environment for the bioactive ingredients, avoid thermal shock, and reduce the loss of heat-sensitive components during spray drying. In addition, compared with the total flavonoid powder prepared by using the traditional organic reagent-ethanol extraction, the total flavonoid powder prepared by the present invention has excellent anti-hygroscopic properties, which helps to improve the stability of the product.

[0023] 4. The low eutectic solvent used in the present invention is an edible raw material with safe and reliable ingredients. The adopted extraction method is simple and fast, and the equipment used is easy to operate, which is conducive to broadening the application scope of total flavonoids from tartary buckwheat sprouts in the food industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Prepare a flow chart for powdered formula.

[0025] Figure 2 This is the effect of ethanol volume fraction on the extraction rate of total flavonoids from buckwheat sprouts.

[0026] Figure 3 The effect of solid-liquid ratio on the extraction rate of total flavonoids from buckwheat sprouts.

[0027] Figure 4 The bioaccessibility of buckwheat sprout flavonoid powder.

[0028] Figure 5 is the retention rate of total flavonoid extract before and after spray drying.

[0029] Figure 6 It is the retention rate of total flavonoid extract in the sample stored under 30% relative humidity conditions.

[0030] Figure 7 It is the retention rate of total flavonoid extract in the sample stored under 70% relative humidity conditions. DETAILED DESCRIPTION

[0031] The present invention is described below by specific embodiments. The technical means not particularly described in the present invention are methods known to those skilled in the art. In addition, the embodiments should be understood as illustrative rather than limiting the scope of the present invention, and the essence and scope of the present invention are limited only by the claims. For those skilled in the art, various changes or modifications to the material components and dosages in these embodiments, without departing from the essence and scope of the present invention, also belong to the protection scope of the present invention.

[0032] The present invention adopts a complex network structure formed by non-covalent bonds such as hydrogen bonds of a deep eutectic solvent (DES), reduces the interaction between solvent molecules, enhances its binding force with flavonoid compounds, and thus improves the solubility of flavonoid compounds. At the same time, the components and molar ratio of DES are adjustable, so that its polarity is more matched with flavonoid compounds, selective dissolution is achieved, and the purity of the target is improved. DES also has the effect of destroying plant cell walls and cell membranes, can promote the release of total flavonoid substances in cells, and has good permeability, accelerating the diffusion of total flavonoids into the solvent. In addition, the low toxicity, low volatility and biocompatibility of DES make it an environmentally friendly green solvent, and can effectively stabilize flavonoid compounds and reduce their degradation in adverse environments such as high temperature and high humidity.

[0033] The tartary buckwheat sprouts can be prepared according to a germination method commonly used in the art, or by the following method provided by the inventors (the embodiments of the present invention all adopt this method to prepare the tartary buckwheat sprouts): The steps of germination of bitter buckwheat include: seed selection, cleaning, seed soaking, germination and harvesting. Specifically: 1) Select high-quality buckwheat seeds with full grains, wash and disinfect them, and then heat-shock them at 50°C; 2) Soak the heat-shocked seeds in a soaking solution (50 ppm gibberellin) for 4 hours, and then rinse with clean water to remove the soaking solution on the surface of the seeds; 3) Spread the seeds evenly on the seedling pots and germinate them in dark and ventilated conditions; 4) After the seeds germinate, move them to a constant temperature and humidity incubator (25℃±2℃, humidity 80%±5%) for alternating dark and light cultivation, 16h of blue light and 8h of darkness. Nutrient solution (5mmol / L L-phenylalanine) is placed at the bottom of the seedling pot. The nutrient solution is replaced once a day, and the nutrient solution is sprayed into the seedling pot every 12h; 5) After 8 days of cultivation, the tartary buckwheat sprouts were harvested, freeze-dried and ground into fine powder.

[0034] The present invention is further explained below through specific implementation modes.

[0035] Example 1 Preparation of total flavonoids extract from buckwheat sprouts (1) Select high-quality buckwheat seeds with full grains, wash and disinfect them, and then heat-shock them at 50°C. Soak the heat-shocked seeds in soaking solution for 4 hours, and then rinse them with clean water to remove the soaking solution on the surface of the seeds; (2) Spread the seeds evenly on the seedling pot and germinate them in dark and ventilated conditions. After the seeds germinate, move them to a constant temperature and humidity incubator for alternating dark and light cultivation, with 16 hours of blue light and 8 hours of darkness. Put nutrient solution at the bottom of the seedling pot, change the nutrient solution once a day, and spray the nutrient solution into the seedling pot every 12 hours. Harvest after 8 days of cultivation, freeze-dry the buckwheat buds and grind them into fine powder.

[0036] (3) Betaine and xylitol were mixed in a molar ratio of 1:1, and 30 wt% of water was added to the whole low eutectic solvent, and the mixture was stirred at 80°C for 4 h until it became colorless and transparent to obtain a low eutectic solvent. Tartary buckwheat bud powder was added to the prepared low eutectic solvent at a material-liquid ratio of 1:10, and the mixture was milled at a ball mill speed of 200 r / min for 60 min, followed by centrifugation to obtain the supernatant, which was filtered through a 0.45 μm microporous filter membrane to obtain a filtrate.

[0037] (4) The 10wt% total flavonoids solution of buckwheat buds obtained by diluting the filtrate with water was used as the core material, and gum arabic and maltodextrin were mixed in a mass ratio of 4:6 to prepare the wall material solution. The core material was then evenly dispersed in the wall material solution with a core-to-wall mass ratio of 1:2, and stirred at 60°C for 30 minutes. After spray drying, the total flavonoids powder of buckwheat buds was obtained. The spray drying conditions were: inlet air temperature of 110°C, outlet air temperature of 70°C, high-pressure pump pressure of 15MPa, and negative pressure in the tower of -140Pa.

[0038] Example 2 Preparation of total flavonoid extract from buckwheat sprouts (1) Select high-quality buckwheat seeds with full grains, wash and disinfect them, and then heat-shock them at 50°C. Soak the heat-shocked seeds in soaking solution for 4 hours, and then rinse them with clean water to remove the soaking solution on the surface of the seeds; (2) Spread the seeds evenly on the seedling pot and germinate them in dark and ventilated conditions. After the seeds germinate, move them to a constant temperature and humidity incubator for alternating dark and light cultivation, with 16 hours of blue light and 8 hours of darkness. Put nutrient solution at the bottom of the seedling pot, change the nutrient solution once a day, and spray the nutrient solution into the seedling pot every 12 hours. Harvest after 8 days of cultivation, freeze-dry the buckwheat buds and grind them into fine powder.

[0039] (3) Betaine and L-proline were mixed in a molar ratio of 1:2, and 20 wt% of water was added to the whole low eutectic solvent, and the mixture was stirred at 70°C for 6 h until it became colorless and transparent to obtain a low eutectic solvent. Tartary buckwheat bud powder was added to the prepared low eutectic solvent at a material-liquid ratio of 1:20, and the mixture was milled at a ball mill speed of 250 r / min for 80 min, followed by centrifugation to obtain the supernatant, which was filtered through a 0.45 μm microporous filter membrane to obtain a filtrate.

[0040] (4) The filtrate was diluted with water to obtain a 15wt% total flavonoids solution of buckwheat buds as the core material, and gum arabic and maltodextrin were mixed in a mass ratio of 4:6 to obtain a wall material solution. The core material was then evenly dispersed in the wall material solution with a core-to-wall mass ratio of 1:3, and stirred at 60°C for 30 minutes. After spray drying, the total flavonoids powder of buckwheat buds was obtained. The spray drying conditions were: inlet air temperature of 120°C, outlet air temperature of 70°C, high-pressure pump pressure of 18Mpa, and negative pressure in the tower of -150Pa.

[0041] Example 3 Preparation of total flavonoids extract from tartary buckwheat sprouts (1) Select high-quality buckwheat seeds with full grains, wash and disinfect them, and then heat-shock them at 50°C. Soak the heat-shocked seeds in soaking solution for 4 hours, and then rinse them with clean water to remove the soaking solution on the surface of the seeds; (2) Spread the seeds evenly on the seedling pot and germinate them in dark and ventilated conditions. After the seeds germinate, move them to a constant temperature and humidity incubator for alternating dark and light cultivation, with 16 hours of blue light and 8 hours of darkness. Put nutrient solution at the bottom of the seedling pot, change the nutrient solution once a day, and spray the nutrient solution into the seedling pot every 12 hours. Harvest after 8 days of cultivation, freeze-dry the buckwheat buds and grind them into fine powder.

[0042] (3) Betaine and malic acid were mixed in a molar ratio of 1:2, and water was added to account for 30 wt% of the total low eutectic solvent, and the mixture was stirred at 80°C for 5 h until the mixture became colorless and transparent to obtain a low eutectic solvent. Tartary buckwheat bud powder was added to the prepared low eutectic solvent at a material-liquid ratio of 1:20, and the mixture was milled at a ball mill speed of 300 r / min for 60 min, followed by centrifugation to obtain the supernatant, which was then filtered through a 0.45 μm microporous filter membrane to obtain a filtrate.

[0043] (4) The filtrate was concentrated (rotary evaporation at 50°C) to obtain a 20wt% total flavonoid solution of buckwheat buds as the core material, and chitosan and skim milk powder were mixed at a mass ratio of 2:5 to obtain a wall material solution. The core material was then evenly dispersed in the wall material solution with a core-to-wall mass ratio of 1:3, and stirred at 60°C for 40 minutes. After spray drying, the total flavonoid powder of buckwheat buds was obtained. The spray drying conditions were: inlet air temperature of 130°C, outlet air temperature of 75°C, high-pressure pump pressure of 18Mpa, and negative pressure in the tower of -180Pa.

[0044] Example 4 Preparation of total flavonoids extract from tartary buckwheat sprouts (1) Select high-quality buckwheat seeds with full grains, wash and disinfect them, and then heat-shock them at 50°C. Soak the heat-shocked seeds in soaking solution for 4 hours, and then rinse them with clean water to remove the soaking solution on the surface of the seeds; (2) Spread the seeds evenly on the seedling pot and germinate them in dark and ventilated conditions. After the seeds germinate, move them to a constant temperature and humidity incubator for alternating dark and light cultivation, with 16 hours of blue light and 8 hours of darkness. Put nutrient solution at the bottom of the seedling pot, change the nutrient solution once a day, and spray the nutrient solution into the seedling pot every 12 hours. Harvest after 8 days of cultivation, freeze-dry the buckwheat buds and grind them into fine powder.

[0045] (3) Betaine and citric acid were mixed in a molar ratio of 1:1, and water was added to account for 20 wt% of the total low eutectic solvent, and the mixture was stirred at 80°C for 5 h until the mixture became colorless and transparent to obtain a low eutectic solvent. Tartary buckwheat bud powder was added to the obtained low eutectic solvent at a material-liquid ratio of 1:30, and the mixture was milled at a ball mill speed of 300 r / min for 90 min, followed by centrifugation to obtain the supernatant, which was then filtered through a 0.45 μm microporous filter membrane to obtain a filtrate.

[0046] (4) The filtrate was concentrated (rotary evaporation at 50°C) to obtain a 25wt% total flavonoid solution of buckwheat buds as the core material, and chitosan and skim milk powder were mixed at a mass ratio of 2:5 to obtain a wall material solution. The core material was then evenly dispersed in the wall material solution with a core-to-wall mass ratio of 1:4, and stirred at 60°C for 40 minutes. After spray drying, the total flavonoid powder of buckwheat buds was obtained. The spray drying conditions were: inlet air temperature of 135°C, outlet air temperature of 80°C, high pressure pump pressure of 20Mpa, and negative pressure in the tower of -160Pa.

[0047] Example 5 Preparation of total flavonoids extract from tartary buckwheat sprouts (1) Select high-quality buckwheat seeds with full grains, wash and disinfect them, and then heat-shock them at 50°C. Soak the heat-shocked seeds in soaking solution for 4 hours, and then rinse them with clean water to remove the soaking solution on the surface of the seeds; (2) Spread the seeds evenly on the seedling pot and germinate them in dark and ventilated conditions. After the seeds germinate, move them to a constant temperature and humidity incubator for alternating dark and light cultivation, with 16 hours of blue light and 8 hours of darkness. Put nutrient solution at the bottom of the seedling pot, change the nutrient solution once a day, and spray the nutrient solution into the seedling pot every 12 hours. Harvest after 8 days of cultivation, freeze-dry the buckwheat buds and grind them into fine powder.

[0048] (3) Betaine was mixed with xylitol and glucose in a molar ratio of 1:1:2, and water was added to account for 50 wt% of the total low eutectic solvent, and the mixture was stirred at 80°C for 6 h until the mixture became colorless and transparent to obtain a low eutectic solvent. Tartary buckwheat bud powder was added to the obtained low eutectic solvent at a material-liquid ratio of 1:40, and the mixture was milled at a ball mill speed of 300 r / min for 90 min, followed by centrifugation to obtain the supernatant, which was then filtered through a 0.45 μm microporous filter membrane to obtain a filtrate.

[0049] (4) The filtrate was concentrated (rotary evaporation at 50°C) to obtain a 30wt% total flavonoid solution of buckwheat buds as the core material, and β-cyclodextrin and glucan were mixed in a mass ratio of 2:3 to obtain a wall material solution. The core material was then evenly dispersed in the wall material solution with a core-to-wall mass ratio of 1:4, and stirred at 60°C for 30 minutes. After spray drying, the total flavonoid powder of buckwheat buds was obtained. The spray drying conditions were: inlet air temperature of 140°C, outlet air temperature of 85°C, high pressure pump pressure of 20Mpa, and negative pressure in the tower of -180Pa.

[0050] Example 6 Preparation of total flavonoid extract from buckwheat sprouts (1) Select high-quality buckwheat seeds with full grains, wash and disinfect them, and then heat-shock them at 50°C. Soak the heat-shocked seeds in soaking solution for 4 hours, and then rinse them with clean water to remove the soaking solution on the surface of the seeds; (2) Spread the seeds evenly on the seedling pot and germinate them in dark and ventilated conditions. After the seeds germinate, move them to a constant temperature and humidity incubator for alternating dark and light cultivation, with 16 hours of blue light and 8 hours of darkness. Put nutrient solution at the bottom of the seedling pot, change the nutrient solution once a day, and spray the nutrient solution into the seedling pot every 12 hours. Harvest after 8 days of cultivation, freeze-dry the buckwheat buds and grind them into fine powder.

[0051] (3) Betaine was mixed with xylitol and citric acid in a molar ratio of 1:1:1, and water accounting for 40 wt% of the total low eutectic solvent was added, and the mixture was stirred at 80°C for 6 h until it became colorless and transparent to obtain a low eutectic solvent. Tartary buckwheat bud powder was added to the prepared low eutectic solvent at a material-liquid ratio of 1:30, and the mixture was milled at a ball mill speed of 350 r / min for 60 min, followed by centrifugation to obtain the supernatant, which was filtered through a 0.45 μm microporous filter membrane to obtain a filtrate.

[0052] (4) The filtrate was concentrated (rotary evaporation at 50°C) to obtain a 35wt% total flavonoid solution of buckwheat buds as the core material, and β-cyclodextrin and glucan were mixed at a mass ratio of 2:3 to obtain a wall material solution. The core material was then evenly dispersed in the wall material solution with a core-to-wall mass ratio of 1:4, and stirred at 60°C for 30 minutes. After spray drying, the total flavonoid powder of buckwheat buds was obtained. The spray drying conditions were: inlet air temperature of 150°C, outlet air temperature of 85°C, high pressure pump pressure of 20Mpa, and negative pressure in the tower of -200Pa.

[0053] Example 7 A formula milk powder and its preparation Formula milk powder preparation flow chart Figure 1 shown.

[0054] Take 2 parts of the total flavonoids powder of tartary buckwheat sprouts prepared in Example 1 and mix them with other raw materials to obtain a formula milk powder with blood sugar lowering effect. The details are as follows: 75 parts of milk powder, 6.4 parts of desalted whey powder, 12 parts of vegetable fat powder, 1 part of oligofructose, 3 parts of inulin, and 2 parts of total flavonoids powder of tartary buckwheat sprouts.

[0055] Among them, the vegetable oil contained in the vegetable fat powder is composed of 40% rapeseed oil, 35% corn oil and 25% coconut oil; The formula milk powder also contains compound vitamins. Every 100g of formula milk powder contains 650μg RE (in terms of retinol) vitamin A, 9.5μg vitamin D, 13.5mg α-TE (in terms of α-tocopherol) vitamin E, and 1.2mg vitamin B 6 , 85mg vitamin C, 380μg folic acid.

[0056] The formula milk powder also contains complex minerals, with each 100g of formula milk powder containing 11mg iron, 3.35mg zinc, 16.2μg selenium, 500μg copper, and 80μg manganese.

[0057] Example 8 A formula milk powder and its preparation Take 3 parts of the total flavonoids powder of tartary buckwheat sprouts prepared in Example 2 and mix with other raw materials to obtain a formula milk powder with blood sugar lowering effect. The details are as follows: 78 parts of milk powder, 10.1 parts of desalted whey powder, 1.25 parts of phytosterol esters, 0.05 parts of fish oil powder, 5 parts of resistant dextrin, 2 parts of inulin, and 3 parts of total flavonoids powder of tartary buckwheat buds.

[0058] The formula milk powder also contains compound vitamins. Every 100g of formula milk powder contains 650μg RE (in terms of retinol) vitamin A, 9.5μg vitamin D, 13.5mg α-TE (in terms of α-tocopherol) vitamin E, and 1.2mg vitamin B 6 , 75mg vitamin C, 380μg folic acid.

[0059] The formula milk powder also contains complex minerals, with each 100g of formula milk powder containing 11mg iron, 3.5mg zinc, 16.2μg selenium, 500μg copper, and 80μg manganese.

[0060] Example 9 A formula milk powder and its preparation Take 4 portions of the total flavonoids powder of tartary buckwheat sprouts prepared in Example 3 and mix them with other raw materials to obtain a formula milk powder with a blood sugar-lowering effect. The details are as follows: 70 parts of milk powder, 6.6 parts of desalted whey powder, 2 parts of bovine colostrum powder, 12 parts of vegetable fat powder, 4 parts of resistant dextrin, 0.8 parts of isomaltooligosaccharide, and 4 parts of total flavonoids powder of tartary buckwheat buds.

[0061] The vegetable oils contained in the vegetable fat powder are composed of 45% low-erucic acid rapeseed oil, 40% sunflower oil and 15% soybean oil; The formula milk powder also contains compound vitamins. Every 100g of formula milk powder contains 650μg RE (in terms of retinol) vitamin A, 9.5μg vitamin D, 13.5mg α-TE (in terms of α-tocopherol) vitamin E, and 1.2mg vitamin B 6 , 85mg vitamin C, 380μg folic acid.

[0062] The formula milk powder also contains complex minerals, with each 100g of formula milk powder containing 360mg calcium, 11mg iron, 3.35mg zinc, 23.2μg selenium, 300μg copper, and 80μg manganese.

[0063] Example 10 A formula milk powder and its preparation Take 5 portions of the total flavonoids powder of tartary buckwheat sprouts prepared in Example 4 and mix them with other raw materials to obtain a formula milk powder with a blood sugar-lowering effect. The details are as follows: 71 parts of milk powder, 15.3 parts of desalted whey powder, 1.25 parts of phytosterol esters, 0.05 parts of fish oil powder, 3 parts of resistant dextrin, 4 parts of inulin, and 5 parts of total flavonoids powder of tartary buckwheat buds.

[0064] The formula milk powder also contains complex vitamins. Every 100g of formula milk powder contains 480μg RE (calculated as retinol) vitamin A, 9.5μg vitamin D, 13mg α-TE (calculated as α-tocopherol) vitamin E, and 75mg vitamin C.

[0065] The formula milk powder also contains complex minerals, with each 100g of formula milk powder containing 360mg calcium, 11mg iron and 3.5mg zinc.

[0066] Example 11 A formula milk powder and its preparation Take 6 portions of the total flavonoids powder of tartary buckwheat sprouts prepared in Example 5 and mix them with other raw materials to obtain a formula milk powder with blood sugar lowering effect. The details are as follows: 76 parts of milk powder, 12 parts of whey protein powder, 0.25 parts of docosahexaenoic acid oil powder, 0.35 parts of arachidonic acid oil powder, 2 parts of galacto-oligosaccharide, 3 parts of raffinose, and 6 parts of total flavonoids powder of tartary buckwheat buds.

[0067] The formula milk powder also contains complex vitamins. Every 100g of formula milk powder contains 360μg RE (calculated as retinol) vitamin A, 6.56μg vitamin D, 13mg α-TE (calculated as α-tocopherol) vitamin E, and 75mg vitamin C.

[0068] The formula milk powder also contains complex minerals, with each 100g of formula milk powder containing 360mg calcium, 11mg iron, 3.5mg zinc and 20μg selenium.

[0069] Example 12 A formula milk powder and its preparation 7 portions of the total flavonoids powder of tartary buckwheat sprouts prepared in Example 6 were mixed with other raw materials to obtain a formula milk powder with a blood sugar-lowering effect. The details are as follows: 78 parts of milk powder, 4 parts of whey protein powder, 5 parts of phytosterol esters, 0.25 parts of docosahexaenoic acid oil powder, 0.35 parts of arachidonic acid oil powder, 2 parts of maltooligosaccharide, 3 parts of raffinose, and 7 parts of total flavonoids powder of tartary buckwheat buds.

[0070] The formula milk powder also contains complex vitamins. Every 100g of formula milk powder contains 360μg RE (calculated as retinol) vitamin A, 6.56μg vitamin D, 13mg α-TE (calculated as α-tocopherol) vitamin E, and 75mg vitamin C.

[0071] The formula milk powder also contains complex minerals, with each 100g of formula milk powder containing 360mg calcium, 11mg iron, 3.5mg zinc and 20μg selenium.

[0072] Comparative Example 1 (1) Effect of ethanol concentration on the extraction rate of total flavonoids from buckwheat sprouts Weigh a certain amount of bitter buckwheat bud powder, add different concentrations of ethanol (40%, 50%, 60%, 70%, 80%, 90%), the solid-liquid ratio is 1:30, grind at a ball mill speed of 200r / min for 60min, then centrifuge to obtain the supernatant, filter with a 0.45μm microporous filter membrane, and concentrate the filtrate by rotary evaporation at 50°C to remove ethanol for later use. The total flavonoid content of the extract was determined at 420nm by aluminum chloride colorimetry, and the standard curve was drawn with rutin standard. The total flavonoid concentration was calculated according to the regression equation, and then the extraction rate of total flavonoids was calculated. The results are as follows: Figure 2 shown.

[0073] Depend on Figure 2It can be seen that within the ethanol concentration range of 40% to 60%, the extraction rate of total flavonoids from buckwheat sprouts gradually increased with the increase of ethanol concentration, and the extraction rate was the highest at 60%; when the ethanol concentration was greater than 60%, the extraction rate of total flavonoids gradually decreased with the increase of ethanol concentration. Therefore, 60% was selected as the optimal ethanol extraction concentration.

[0074] (2) Effect of solid-liquid ratio on the extraction rate of total flavonoids from buckwheat sprouts Weigh a certain amount of buckwheat bud powder, add 60% ethanol, and measure the effect of different solid-liquid ratios on the extraction rate of total flavonoids from buckwheat buds. The rest of the experimental process is the same as (1). The results are as follows: Figure 3 shown.

[0075] Depend on Figure 3 It can be seen that with the increase of the solid-liquid ratio, the extraction rate of total flavonoids gradually increased; when the solid-liquid ratio exceeded 1:40 (g / mL), the extraction rate of total flavonoids began to decrease. Therefore, the solid-liquid ratio of 1:40 (g / mL) was selected as the optimal extraction ratio.

[0076] In summary, the optimal process parameters for extracting total flavonoids from buckwheat sprouts with ethanol are: 60% ethanol concentration and solid-liquid ratio of 1:40 (g / mL). After three parallel tests, the average extraction rate of total flavonoids from buckwheat sprouts under this condition was 6.46%, and the total flavonoids obtained under this process condition were used for subsequent tests.

[0077] Preparation of total flavonoids powder from tartary buckwheat sprouts (Comparative Example 1): Weigh a certain amount of buckwheat bud powder, add 60% ethanol, the solid-liquid ratio is 1:40, grind at a ball mill speed of 200 r / min for 60 min, then centrifuge to obtain the supernatant, and filter with a 0.45 μm microporous membrane; The 10wt% total flavonoids solution of buckwheat buds obtained by diluting the filtrate was used as the core material, and the wall material solution was prepared by mixing gum arabic and maltodextrin at a mass ratio of 4:6. The core material was then evenly dispersed in the wall material solution, with a core-wall mass ratio of 1:2, and stirred at 60°C for 30 minutes. After spray drying, the total flavonoids powder of buckwheat buds was obtained. The spray drying conditions were: inlet air temperature of 110°C, outlet air temperature of 70°C, high pressure pump pressure of 15Mpa, and negative pressure in the tower of -140Pa.

[0078] Comparative Example 2 Preparation of total flavonoids extract from buckwheat sprouts Referring to Comparative Example 1, the effects of ethanol concentration (40%, 50%, 60%, 70%, 80%, 90%), extraction time (40, 60, 80, 100, 120 min), solid-liquid ratio (1:20, 1:30, 1:40, 1:50, 1:60, 1:70 (g / mL)), extraction temperature (50, 60, 70, 80, 90, 100 ° C) and ultrasonic frequency (30, 40, 50, 60, 70, 80, 90, 100 kHz) on the extraction yield of total flavonoids were investigated respectively.

[0079] The optimal process parameters were as follows: 70% ethanol concentration, solid-liquid ratio 1:50 (g / mL), extraction time 80 min, extraction temperature 80 °C and ultrasonic frequency 70 kHz. After three parallel tests, the average extraction rate of total flavonoids from buckwheat buds under this condition was 6.97%, and the total flavonoids obtained under this process condition were used for subsequent tests.

[0080] Preparation of total flavonoids powder from tartary buckwheat sprouts (Comparative Example 2): A certain amount of bitter buckwheat bud powder was weighed, 70% ethanol was added, the solid-liquid ratio was 1:50, the extraction time was 80 min, the extraction temperature was 80 °C and the ultrasonic frequency was 70 kHz, then the supernatant was centrifuged and filtered with a 0.45 μm microporous membrane; The 10wt% total flavonoids solution of buckwheat buds obtained by diluting the filtrate was used as the core material, and the wall material solution was prepared by mixing gum arabic and maltodextrin at a mass ratio of 4:6. The core material was then evenly dispersed in the wall material solution, with a core-wall mass ratio of 1:2, and stirred at 60°C for 30 minutes. After spray drying, the total flavonoids powder of buckwheat buds was obtained. The spray drying conditions were: inlet air temperature of 110°C, outlet air temperature of 70°C, high pressure pump pressure of 15Mpa, and negative pressure in the tower of -140Pa.

[0081] Comparative Example 3 A formula milk powder and its preparation Take 2 portions of the total flavonoids powder of tartary buckwheat sprouts prepared in Comparative Example 1 and mix with other raw materials to obtain a formula milk powder with the effect of lowering blood sugar. The details are as follows: 75 parts of milk powder, 6.4 parts of desalted whey powder, 12 parts of vegetable fat powder, 1 part of oligofructose, 3 parts of inulin, and 2 parts of total flavonoids powder of tartary buckwheat sprouts.

[0082] Among them, the vegetable oil contained in the vegetable fat powder is composed of 40% rapeseed oil, 35% corn oil and 25% coconut oil; The formula milk powder also contains compound vitamins. Every 100g of formula milk powder contains 650μg RE (in terms of retinol) vitamin A, 9.5μg vitamin D, 13.5mg α-TE (in terms of α-tocopherol) vitamin E, and 1.2mg vitamin B 6, 85mg vitamin C, 380μg folic acid.

[0083] The formula milk powder also contains complex minerals, with each 100g of formula milk powder containing 11mg iron, 3.35mg zinc, 16.2μg selenium, 500μg copper, and 80μg manganese.

[0084] Comparative Example 4 A formula milk powder and its preparation Take 2 parts of the total flavonoids powder of tartary buckwheat sprouts prepared in Comparative Example 2 and mix with other raw materials to obtain a formula milk powder with blood sugar lowering effect. The other raw material components are the same as those in Comparative Example 3.

[0085] Experiment 1 This experiment studied Examples 1 to 6, and the yield of total flavonoids by low eutectic solvent-assisted mechanochemical extraction. The results are shown in Table 1.

[0086] Table 1 Extraction rate of total flavonoids from buckwheat sprouts

[0087] It can be seen from the data in Table 1 that the total flavonoid extraction rates of Examples 1-6 of the present invention are all higher than those of Comparative Examples 1 and 2, indicating that the deep eutectic solvent is helpful for the extraction of total flavonoid compounds in buckwheat buds. In addition, from the results of Examples 1-6, it can be seen that the total flavonoid extraction rate of Example 1 is the lowest (7.42%), while that of Example 6 is the highest (11.23%), indicating that when the deep eutectic solvent is betaine-xylitol-citric acid, it has a better extraction effect on the total flavonoids of buckwheat buds.

[0088] Experiment 2 This experiment studied the solubility of the flavonoid compounds prepared in Examples 1 to 6 and the comparative example in water.

[0089] An excess of the spray-dried sample (2 g) was added to 10 mL of distilled water, placed in a 40°C water bath for 20 min, and insoluble matter was removed using a Millipore filter (0.45 μm). The amount of dissolved flavonoids in the sample was determined by high performance liquid chromatography. The results are shown in Table 2.

[0090] Table 2 Solubility of flavonoids

[0091] As shown in Table 2, the amount of flavonoids dissolved in the samples of Examples 1-6 is higher than that in Comparative Examples 1 and 2, indicating that the deep eutectic solvent can improve the water solubility of the flavonoids after spray drying. And when the deep eutectic solvent is betaine-xylitol-citric acid, it has the best effect on improving the solubility of flavonoids.

[0092] Experiment 3 This experiment studied the bioaccessibility of the tartary buckwheat sprout flavonoid powder prepared by spray drying in Examples 1 to 6 and the comparative example.

[0093] Bioaccessibility is the proportion of active factors that can be absorbed after oral ingestion, that is, the proportion of active factors released from the food matrix and dissolved in the intestinal fluid after gastrointestinal digestion. The determination of bioaccessibility is an important indicator for evaluating the bioavailability of active factors, which can generally be determined using an in vitro simulated digestion model.

[0094] According to the method of Wu et al. (Wu Xiaolin, Xu Na, Cheng Ce, et al. Encapsulation ofhydrophobic capsaicin within the aqueous phase of water-in-oil high internalphase emulsions: Controlled release, reduced irritation, and enhancedbioaccessibility[J]. Food Hydrocolloids, 2022, 123: 107184.), simulated oral digestive fluid, gastric digestive fluid and small intestinal digestive fluid were prepared, and digestion experiments were conducted.

[0095] (1) Preparation of digestive juice ①Simulated oral digestive fluid (SSF): 200mL distilled water, 318.8mg sodium chloride, 65.6mg ammonium nitrate, 40.4mg potassium chloride, 61.6mg potassium citrate, 127.2mg potassium dihydrogen phosphate, 4.2mg potassium dihydrogen urate, 39.6mg urea, 29.2mg sodium lactate.

[0096] ②Simulated gastric digestive fluid (SGF): 200 mL distilled water, 400 mg sodium chloride, 1.4 mL concentrated hydrochloric acid.

[0097] ③Simulated small intestinal fluid (SIF): 100 mL distilled water, 21.87 g sodium chloride, 3.67 g calcium chloride monohydrate.

[0098] ④Digestive fluid should be prepared in advance: ⅰ. Dissolve the mucosal protein with SSF one night before use and prepare a simulated oral digestive fluid containing 3 mg / mL mucosal protein; ⅱ. Dissolve pepsin with SGF 45 minutes before use to prepare a simulated gastric digestive fluid containing 3.2 mg / mL pepsin; ⅲ. When using, temporarily dissolve lipase, pancreatin, and bile salts with 5 mM PBS (pH 7.0) to obtain 24 mg / mL lipase solution, 24 mg / mL pancreatin solution, and 54 mg / mL bile salt solution; All solutions to be used were preheated to 37°C before digestion began.

[0099] (2) In vitro digestion experiment Oral digestion: Take 1g of sample and add distilled water to a total mass of 7.5g, then add 7.5mL of simulated oral digestion fluid containing mucosal proteins and mix, quickly adjust the pH of the mixture to 6.8, and digest in a 37℃ constant temperature water bath shaker for 10min; Gastric digestion: Take 15 mL of simulated gastric digestion solution containing pepsin and add it to the solution after oral digestion. The pH of the mixed system is quickly adjusted to 2.5, and digested in a constant temperature water bath shaker at 37°C for 2 h. Intestinal digestion: Add 1.5 mL of simulated small intestinal digestive fluid and 3.5 mL of bile salt solution to the solution after gastric digestion, and adjust the pH of the mixed system to 6.8. Then add 2.5 mL of lipase solution and 2.5 mL of pancreatic enzyme solution, adjust the pH of the mixed system to 7.0, and digest at 37°C for 2 hours. After digestion, centrifuge and take the supernatant, and determine the soluble (i.e. absorbable) total flavonoid content in the digestive fluid.

[0100] Bioaccessibility W(%) = 100×W 1 / W 0 Among them, W 0 is the content of total flavonoids in the sample before digestion; W 1 is the content of total flavonoids in the digested sample.

[0101] The bioaccessibility results of the samples are as follows: Figure 4 As shown. Compared with Comparative Example 1 and Comparative Example 2, the bioaccessibility of the tartary buckwheat bud flavonoid powder prepared in Examples 1-6 of the present invention is improved, indicating that under the simulated gastrointestinal environment, the total flavonoid powder of tartary buckwheat buds prepared by extraction with a low eutectic solvent has a high bioavailability, that is, a high proportion of effective ingredients that can be digested and absorbed by the body and exert their effects. The bioaccessibility of Example 6 is the highest, indicating that the optimal low eutectic solvent is betaine-xylitol-citric acid.

[0102] Experiment 4 This experiment studied the retention rate of total flavonoid extracts in the spray-dried encapsulated samples of Examples 1 to 6 and the comparative example.

[0103] High performance liquid chromatography was used to analyze the contents of flavonoids in the samples before and after spray drying, and then the effect of spray drying on the retention of flavonoids was evaluated.

[0104] Retention rate R(%) = 100×C 1 / C 0 Among them, C 0 is the content of total flavonoids in the mixed solution before spray drying; C 1 is the content of total flavonoids in the sample after spray drying.

[0105] The retention rate results are as follows Figure 5 As shown. Compared with Comparative Examples 1 and 2, the retention rate of the total flavonoid extract in the sample powders prepared in Examples 1-6 of the present invention is significantly improved. This may be because the low eutectic solvent provides a milder internal environment, avoiding thermal shock, thereby reducing the loss of heat-sensitive components. The retention rate of the total flavonoid extract in the sample of Example 6 is the highest, indicating that the bioactive ingredients (total flavonoid extract) have a higher stability under the betaine-xylitol-citric acid low eutectic solvent system.

[0106] Experiment 5 This experiment studied the retention rate of the total flavonoid extract of the spray-dried samples prepared in Examples 1 to 6 and the comparative example after storage at 25° C. and relative humidity of 30% and 70% for 60 days.

[0107] During storage, especially when exposed to oxygen, light, high temperature and high humidity, flavonoids are easily oxidized and decomposed, resulting in changes in their physical and chemical properties and biological activities. High performance liquid chromatography was used to analyze the content of flavonoids in the samples before and after storage, and then to evaluate the stability of the active ingredients in the encapsulated samples. The results are as follows Figure 6 and Figure 7 shown.

[0108] Depend on Figure 6 and Figure 7 It can be seen that under the conditions of 30% and 70% relative humidity, compared with Comparative Example 1 and Comparative Example 2, the retention rate of the total flavonoid extract in the samples prepared in Examples 1-6 is higher, that is, the samples prepared in Examples 1 to 6 have excellent anti-hygroscopic properties, indicating that the powders of the samples in Examples 1-6 form a more solid shell structure, which may be attributed to the presence of the low eutectic solvent, which promotes its interaction with the wall material, thereby improving the anti-hygroscopic ability of the sample.

[0109] Experiment 6 In this experiment, sensory evaluation was conducted on the prepared formula milk powder, and the sensory indicators included: color, texture, dissolution, taste and smell. The results are shown in Table 3.

[0110] Table 3 Sensory evaluation results of formula milk powder

[0111] It can be seen from the data in the above table that, compared with Comparative Examples 3 and 4, Examples 7-12 have better sensory evaluations overall, and Example 12 has the highest total evaluation score. Among them, compared with other example groups, Example 12 has lower scores for taste and smell, which may be due to the high addition of total flavonoid powder of tartary buckwheat sprouts affecting the flavor and taste of milk powder, and the appropriate addition of extracts helps to improve the taste and nutrition of milk powder.

[0112] Although the present invention has been disclosed as above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make various changes, modifications, substitutions and variations in form and details to these embodiments without departing from the spirit and principles of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for extracting total flavonoids from tartary buckwheat sprouts, characterized in that: The method uses tartary buckwheat buds as raw materials, adds tartary buckwheat bud powder into a low eutectic solvent, grinds, centrifuges to obtain a supernatant, dilutes or concentrates the tartary buckwheat bud total flavonoids solution with water to obtain a core material, evenly disperses the core material in a wall material solution, and spray-dries to obtain tartary buckwheat bud total flavonoids powder.

2. The method for extracting total flavonoids from tartary buckwheat sprouts according to claim 1, characterized in that: The low eutectic solvent uses betaine as a hydrogen bond acceptor; in the low eutectic solvent, betaine is mixed with different types of hydrogen bond donors in a molar ratio of 1:1-6; the hydrogen bond donor includes one or more of polyols, amino acids, and organic acids; the low eutectic solvent also contains water, and the water accounts for 20%-60% of the total weight of the low eutectic solvent.

3. The method for extracting total flavonoids from tartary buckwheat sprouts according to claim 2, characterized in that: The polyol includes one or more of xylitol, sorbitol, and glucose; The amino acids include one or more of L-lysine and L-proline; The organic acid includes one or more of citric acid and malic acid.

4. The method for extracting total flavonoids from tartary buckwheat sprouts according to claim 1, characterized in that: The tartary buckwheat bud powder is added to a low eutectic solvent, and after grinding, the supernatant is obtained by centrifugation, and then filtered with a 0.45 μm microporous filter membrane to obtain a filtrate; the tartary buckwheat bud total flavonoid solution diluted or concentrated to 10wt%~40wt% is used as a core material.

5. The method for extracting total flavonoids from tartary buckwheat sprouts according to claim 1, characterized in that: The weight ratio of the core material to the wall material is 1:1-5; The wall material is one or more of beta-cyclodextrin, maltodextrin, gum arabic, dextran, chitosan, whey protein and skimmed milk powder.

6. The method for extracting total flavonoids from tartary buckwheat sprouts according to claim 1, characterized in that: The spray drying conditions are: air inlet temperature 100-180°C, air outlet temperature 70-90°C, high pressure pump pressure 8-25Mpa, and negative pressure in the tower -50-300Pa.

7. Tartary buckwheat sprout total flavonoids powder prepared by the method according to any one of claims 1 to 6.

8. Use of the total flavonoids powder of tartary buckwheat sprouts according to claim 7 in the preparation of blood sugar lowering products.

9. A hypoglycemic formula milk powder, characterized in that: The formula milk powder comprises the following components in parts by weight: 70-89 parts of milk solid composition, 0.5-15 parts of fat composition, 2-10 parts of dietary fiber composition, and 2-8 parts of total flavonoids powder of tartary buckwheat sprouts; The preparation method of the tartary buckwheat sprout total flavonoids powder is as shown in claim 1.

10. A hypoglycemic formula milk powder as claimed in claim 9, characterized in that: The milk solid composition includes but is not limited to one or more of milk powder, bovine colostrum powder, desalted whey powder, and whey protein powder; The fat composition includes but is not limited to one or more of vegetable fat powder, medium chain triglyceride, fish oil powder, plant sterol ester, docosahexaenoic acid oil powder, and arachidonic acid oil powder; The vegetable fat powder contains one or more of the following: rapeseed oil, corn oil, coconut oil, linseed oil, palm oil, low-erucic acid rapeseed oil, sunflower oil, high-oleic acid sunflower oil, and soybean oil; The dietary fiber composition includes but is not limited to one or more of oligofructose, inulin, polydextrose, resistant dextrin, isomaltooligosaccharide, oligomalto-oligosaccharide, galacto-oligosaccharide and raffinose; The formula milk powder also contains compound vitamins and compound minerals; The specific sources and added amounts of the vitamins and minerals are in compliance with the requirements of GB 14880-2012 standard.

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