WO2008063006A1

WO2008063006A1 - Extracting method of buckwheat bud using ultrasonic

Info

Publication number: WO2008063006A1
Application number: PCT/KR2007/005873
Authority: WO
Inventors: Ok Soon Kim
Original assignee: Ok Soon Kim
Priority date: 2006-11-22
Filing date: 2007-11-21
Publication date: 2008-05-29
Also published as: KR100779855B1

Abstract

Disclosed is a method for high-efficiency extraction of active ingredients from buckwheat sprouts, which secures harmlessness while preventing environmental contamination occurring during provision of a liquid or powder extract. The present invention enables high-efficiency extraction of antioxidant substances and natural materials which are contained in buckwheat sprouts at a high level and are beneficial to the human body. The method comprises germinating buckwheat seeds to grow buckwheat sprouts (germination step), grinding the thus-grown buckwheat sprouts to increase a specific surface area thereof, thereby improving a solvent extraction rate of buckwheat sprouts (grinding step), adding a solvent thereto to extract antioxidant substances and natural materials, followed by ultrasonic extraction (ultrasonic application step), removing solids of the buckwheat sprouts extracted in the solvent (dehydration step), and packaging an extracted liquid material or powder thereof (packaging step).

Description

EXTRACTING METHOD OF BUCKWHEAT BUD USING

ULTRASONIC

Technical Field

[1] The present invention relates to a high-efficiency extraction method of antioxidant substances and natural materials which are contained in buckwheat sprouts at a high level.

[2] As a result of a variety of extensive and intensive studies and experiments, the inventors of the present invention have discovered that a buckwheat sprout liquid or powder extract can be obtained by a process comprising the steps of germinating buckwheat seeds to grow buckwheat sprouts (germination step), grinding the thus- grown buckwheat sprouts to increase a specific surface area thereof, thereby improving a solvent extraction rate of buckwheat sprouts (grinding step), adding a solvent thereto to extract antioxidant substances and natural materials, followed by ultrasonic extraction (ultrasonic application step), removing solids of the buckwheat sprouts extracted in the solvent (dehydration step), and packaging an extracted liquid material or a powder thereof (packaging step). The present invention has been completed based on these findings.

[3]

Background Art

[4] Humans are instinctively eager to achieve longevity. Individual health conditions can be said to be a basis capable of satisfying such a strong desire.

[5] Examples of diseases resulting from poor or non-physical activity of humans in a modern life style may include hypertension, myocardial infarction, angina pectoris, various stresses, obesity, and the like. In order to prevent the incidence of such diseases, people are devoted to physical exercise or otherwise take nutritive elements beneficial to the human body. In particular, a great deal of interest has been increasingly focused on health care via intake of beneficial ingredients contained in natural foods and natural products, not nutritive elements provided by chemical synthesis.

[6] Among foods beneficial to the human body, buckwheat is an excellent food having a high nutritive value, and has a higher protein content of 12 to 14%, as compared to other cereals. Further, buckwheat protein is highly nutritive due to a high content of an essential amino acid, lysine, and also contains a large amount of rutin which enhances resistance of capillary vessels and prevents vascular damage including cerebral hemorrhage resulting from hypertension. [7] Even though it is a starch crop, buckwheat has a high protein content and contains vitamins such as Bl, B 2 and nicotinic acid. Therefore, buckwheat has a high nutritive value and help in improvement of appetite. A buckwheat powder is used as a raw material for making buckwheat jelly or noodles which have been widely and popularly eaten in Korea since ancient times. Further, the buckwheat plant has a high content of cellulose and contains rutin, and therefore is used as an anthelmintic or hypotensive drug. Sometimes, the buckwheat plant is also cultivated for production of such a rutin ingredient.

[8] Further, buckwheat sprouts contain larger amounts of antioxidant substances (such as rutin, aspartic acid, glutamic acid, lysine, etc.), vitamins, inorganic ingredients and essential amino acids, as compared to other cereals or vegetables. A great deal of research and study has been published on buckwheat sprouts since the rutin ingredient particularly abundant in the buckwheat herb exhibits specific therapeutic effects for prevention of arteriosclerosis or hypertension. Further, buckwheat sprouts contain large amounts of potent antioxidant substances which strengthen capillary vessels. As a result, this plant has beneficial effects that strengthen sexual function of middle-aged men and also provide lustrous skin of women.

[9] Further, rutin contains large amounts of active ingredients such as polyphenol and consequently is a physiologically active substance having excellent therapeutic effects for diabetes, hypertension, and vascular diseases. Similar to saponins of ginseng and wild ginseng plants, rutin belongs to vitamin P-like compounds. Since the 1960s, a great deal of research and study has been actively undertaken on the feasibility of rutin as a therapeutic agent for vascular diseases.

[10] Buckwheat sprouts are obtained by conventional cultivation as in bean sprouts or green bean sprouts. With reports showing that co-uptake of buckwheat sprouts with meat-based meals promotes digestive function of the body, intake of buckwheat sprouts in the form of cooked vegetables, soup materials or herb salads is anticipated to be helpful for promotion of health, which has thereby brought about a gradual increase of interest into utilization of buckwheat sprouts.

[11] Meanwhile, the buckwheat sprout is a moisture-containing food and is thus highly susceptible to putrefaction when it is kept under poor storage conditions or is exposed to inferior circulation conditions. For these reasons, there may be various difficulties with easy and widespread intake of buckwheat sprouts.

[12] Therefore, in order to furnish active ingredients of the buckwheat sprouts, individual ingredients contained in the buckwheat sprouts may be preferably provided in the form of an extract or powder.

[13] As a method for effective extraction of active ingredients of buckwheat sprouts,

Korean Patent Application No. 10-2004-0017054 discloses a method for preparing a ratin-containing extract from hydroponically-cultivated buckwheat herb, which is carried out using a heat source of 50 to 8O⁰C and a 30 to 8O⁰C ethanol aqueous solution or a 3 to 15% acetic acid aqueous solution as a solvent.

[14] However, the above-mentioned extraction method is only focused on extraction of rutin compounds contained in buckwheat sprouts, so it is considered that extractability of aspartic acid, glutamic acid and lysine ingredients beneficial to the human body, other than the rutin compound, is very low, or it is almost impossible to extract such beneficial ingredients.

[15] Further, when it is desired to extract active ingredients directly from buckwheat sprouts without a grinding process, a very small specific- surface area of the raw material results in extremely low extractability of active compounds into an extraction solvent. Consequently, the long-term extraction under high-temperature water conditions may result in high risk of active ingredient destruction. Further, since the 3 to 15% acetic acid aqueous solution is used as the extraction solvent, acetic acid reacts with alkaline ingredients, such as Na, Ca, Mg and K in the extract, when it is in the form of a dried powder, thereby resulting in formation of alkali acetate giving off a slightly acetic acid odor which will cause rejection against intake of the product. Particularly when the product is a liquid extract containing an acetic acid solvent, a strong odor of acetic acid causes problems associated with low drinkability and eatability thereof.

[16] Therefore, the present invention is conceived to provide an efficient extraction method of beneficial ingredients such as aspartic acid, glutamic acid and lysine as well as rutin, via a simple process, and simultaneously is to obtain an extract having no toxicity or malodor of a solvent.

[17]

Disclosure of Invention Technical Problem

[18] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a solid powder or liquid extract from buckwheat sprouts containing a large amount of active ingredients including antioxidant substances.

[19] More specifically, the object of the present invention is to provide a method for high-efficiency extraction of harmless or odorless active ingredients from buckwheat sprouts, while preventing environmental contamination occurring during provision of a liquid or powder extract which is intended for easy intake of ingredients beneficial to the human body extracted from buckwheat sprouts. Technical Solution [20] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a solvent extraction method of active ingredients from buckwheat sprouts, and a powder or liquid extract produced therefrom.

[21]

Advantageous Effects

[22] As will be illustrated hereinafter, the present invention provides a liquid or powder extract of buckwheat sprouts which is produced by a method comprising germination, grinding, ultrasonic application, dehydration, and packaging steps to enhance the ex- tractability of buckwheat sprout ingredients without a supply of high-thermal energy. Therefore, the buckwheat extract of the present invention is superior in economic efficiency, and provides various beneficial effects such as skin nourishing to give luster and/or brightness of skin, rapid recovery from alcohol hangover, and blood pressure-, cholesterol- and blood sugar-lowering activity.

[23] The present invention is to provide a method for high-efficiency extraction of buckwheat sprout active ingredients, which secures harmlessness while preventing environmental contamination which may occur during provision of a liquid or powder extract which is intended for easy intake of ingredients beneficial to the human body extracted from buckwheat sprouts,

[24]

Brief Description of the Drawings

[25] FIG. 1 is a total ion chromatogram of an extract of the present invention, as measured by LC/MS;

[26] FIG. 2 is a LC/MS spectrum of an extract of the present invention, as measured by

LC/MS;

[27] FIG. 3 is a total ion chromatogram of a rutin standard for quantitative analysis of a rutin compound extracted by an extraction method of the present invention; and

[28] FIG. 4 is a LC/MS spectrum of a rutin standard compound.

[29]

Best Mode for Carrying Out the Invention

[30] Hereinafter, the present invention will be described in more detail.

[31] The present invention discloses a technical idea for obtaining a liquid extract of buckwheat sprouts, comprising germinating buckwheat seeds to grow buckwheat sprouts (germination step), grinding the thus-grown buckwheat sprouts to increase a specific surface area thereof, thereby improving a solvent extraction rate of buckwheat sprouts (grinding step), adding a solvent thereto to extract antioxidant substances and natural materials, followed by ultrasonic application (ultrasonic extraction step), removing solids of buckwheat sprouts extracted in the solvent (dehydration step), and packaging the dehydrated liquid material as a liquid extract.

[32] Alternatively, the liquid extract may be dried to obtain a solid powder which is then packaged to provide a powder extract of buckwheat sprouts.

[33] In an aspect as described above, the present invention is aimed to provide a solvent extraction method of buckwheat sprouts for extracting active ingredients beneficial to the human body, the method comprising germinating buckwheat seeds to grow buckwheat sprouts (germination step), grinding the buckwheat sprouts to increase a specific surface area thereof, thereby improving a solvent extraction rate of buckwheat sprouts (grinding step), adding a solvent thereto to extract antioxidant substances and natural materials, followed by ultrasonic application (ultrasonic extraction step), removing solids of buckwheat sprouts extracted in the solvent (dehydration step), and packaging the dehydrated liquid material as a liquid extract. Instead of packaging the dehydrated liquid material as an extract, the extraction method of buckwheat sprouts according to the present invention may comprise drying the liquid extract to obtain a solid powder and then packaging the solid powder to provide a buckwheat sprout powder extract.

[34] More specifically, the buckwheat germination step may include dipping of buckwheat seeds in water for 12 to 36 hours, sieving the mixture, supplying to the buckwheat seeds a sufficient amount of water selected from distilled water, tap water, underground water and bottled water, at regular intervals of 6 to 8 hours, and growing the buckwheat seeds at a temperature of 20 to 38⁰C for 5 to 9 days to provide buckwheat sprouts. Alternatively, the buckwheat germination step may include dipping of buckwheat seeds in water for 12 to 36 hours, sieving the mixture, supplying to the buckwheat seeds a sufficient amount of water by hydroponic cultivation, at regular intervals of 6 to 8 hours, and growing the buckwheat seeds at a temperature of 20 to 38⁰C for 5 to 9 days to provide buckwheat sprouts.

[35] When it is desired to obtain buckwheat sprouts via hydroponic cultivation, irrigation water for hydroponic cultivation may be water containing 0.8 to 2.0% by weight of nitrogen, 0.2 to 0.5% by weight of phosphorus, 0.5 to 2% by weight of potassium, 0.05 to 0.2% by weight of magnesium, 10 to 30 ppm of boron, 50 to 200 ppm of iron, 35 to 75 ppm of manganese, 10 to 25 ppm of zinc, 4 to 8 ppm of copper, and 0.05 to 0.2 ppm of molybdenum. The buckwheat sprout grinding step includes adding 10 to 60 parts by weight of water to buckwheat sprouts, based on 100 parts by weight of buckwheat sprouts, and grinding the mixture using a grinding mill at the rotational speed of 100 to 2,000 rpm. An extraction vessel used in the ultrasonic extraction step is made of stainless steel selected from stainless-304, stainless-316 and stainless-316L, one ultrasonic generator is installed per an extraction vessel internal area of 30 to 90 D, and an extraction process may be carried out using automated equipment which can control an extraction temperature to be within a range of 25 to 8O⁰C and an extraction time to be within a range of 20 min to 2 hours.

[36] The extraction solvent may be water selected from distilled water, tap water, underground water and bottled water. Further, the extraction solvent may be at least one organic solvent selected from methylene chloride, ether, ethyl acetate, acetone, butanol, isopropanol (IPA: 2-propanol), ethanol and methanol. Further, the extraction process may be carried out using a mixed solvent of 5 to 35 parts by weight of water with 100 parts by weight of the organic solvent.

[37]

Mode for the Invention

[38] Hereinafter, embodiments to specifically implement the technical idea of the present invention will be described with reference to an extraction method of buckwheat sprouts using ultrasonic waves.

[39] There is no particular limit to the germination method of buckwheat sprouts. For example, similar to a conventional method for growth of bean sprouts, the buckwheat sprout germination step may be carried out under germination conditions that continuously supply a sufficient amount of water, simultaneously with control of temperature and humidity. Preferably, hydroponic cultivation conditions may be more advantageous.

[40] The conventional germination method includes dipping buckwheat seeds in water for 12 to 36 hours, followed by sieving to remove water, and cultivating buckwheat seeds at a proper temperature for about 5 to 9 days while supplying a sufficient amount of water at regular intervals of 6 to 8 hours to provide buckwheat sprouts with a height of 10 to 18 D.

[41] When the hydroponic cultivation method is employed to provide buckwheat sprouts, traditional hydroponic cultivation may be used except that inorganic nutrients are added to the irrigation water. Preferably, the hydroponic cultivation may be carried out with irrigation of water containing proper amounts of major fertilizer ingredients, e.g. nitrogen (N), phosphorus (P), potassium (K) and trace elements such as calcium (Ca), magnesium (Mg), boron (B), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), and molybdenum (Mo). The hydroponic cultivation water may contain major elements of nitrogen, phosphorus and potassium at concentrations of 1,000 ppm (0.1 wt%) to 2.0 wt%, and trace elements of magnesium, boron, iron, manganese, zinc, copper and molybdenum at concentrations of 0.1 ppm to 2,000 ppm.

[42] When the hydroponic cultivation water contains none or an infinitesimal quantity of nutritive elements, this may result in very poor growth of buckwheat sprouts, deficiency of nutritive elements, and deterioration of texture and freshness. If contents of the major and minor elements are excessively high, growth of buckwheat may be rapid, but an excessive supply of the nutritive elements cannot provide optimum growth of buckwheat, in conjunction with incidence of physiological disorders. Therefore, proper amounts of the major elements may be preferably 0.8 to 2.0% by weight for nitrogen (N), 0.5 to 0.2% by weight for phosphorus (P), and 0.5 to 2% by weight for potassium (K), whereas proper amounts of trace elements may be preferably 0.05 to 0.2% by weight for magnesium (Mg), 10 to 30 ppm for boron (B), 50 to 200 ppm for iron (Fe), 35 to 75 ppm for manganese (Mn), 10 to 25 ppm for zinc (Zn), 4 to 8 ppm for copper (Cu), and 0.05 to 0.2 ppm for molybdenum (Mo). In addition to these elements, hydrogen, carbon, oxygen and sulfur elements may be further added at a concentration of 0.1 to 4.5% by weight to water.

[43] A temperature of the cultivation vessel may be in a range of preferably 20 to 38⁰C, more preferably 25 to 35⁰C. If the cultivation temperature is less than 2O⁰C, this may result in poor growth of buckwheat sprouts. On the other hand, if the cultivation temperature is more than 38⁰C, buckwheat sprouts may be highly susceptible to rot during a growing period. Therefore, it is preferred to maintain the cultivation temperature in a range of 20 to 38⁰C.

[44] The buckwheat sprout grinding step may be carried out using a high-speed grinding mill equipped with blades. There is no particular limit to size, shape, and rotational speed of blades. As long as overflow of contents from the cultivation vessel, which may occur due to incidence of a whirlpool by rotation of the rotating shaft and blades, is prevented, and safety supervision for an operator is secured during the grinding process, it is possible to employ any kind of grinding machines.

[45] The blade rotational speed during the grinding process may be in a range of 100 to

2,000 rpm, preferably 300 to 1,500 rpm, most preferably 500 to 750 rpm. If the rotational speed is less than 100 rpm, a grinding rate may be lowered even though the blade edges are sharp, and a large particle size of the thus-ground particles results in a relatively large specific-surface area, which is contrary to the technical idea of the present invention. On the other hand, if the rotational speed is higher than 2,000 rpm, the rotational speed is very high and therefore there may be financial burden associated with purchase of an expensive high-speed motor and safety problems for operators. For these reasons, it is advantageous to carry out the grinding process in the above- specified range of blade rotational speed.

[46] In order to further enhance grinding efficiency during the grinding process, grinding may be preferably carried out with addition of 10 to 60 parts by weight, more preferably 10 to 25 parts by weight of water, based on 100 parts by weight of buckwheat sprouts.

[47] An apparatus for supplying ultrasonic waves may be employed for extraction of an- tioxidant substances and natural materials contained in buckwheat sprouts. For this purpose, one or more vibrators generating ultrasonic waves may be provided at the bottom of the extraction vessel. If the extraction vessel is small or the extraction amount of buckwheat sprouts is low, one ultrasonic generator may be installed. When it is desired to carry out large-scale extraction, a plurality of the ultrasonic generators may be advantageously installed in order to enhance the extraction efficiency. Preferably, one ultrasonic generator is installed per an extraction vessel internal area of 30 to 90 D.

[48] In order to further enhance the extraction efficiency, a heating device may be additionally provided in conjunction with the ultrasonic generator installed at the bottom of the extraction vessel. According to intentions and demands of the operator, a controller capable of automatically controlling an extraction temperature and time may be further provided with the extraction vessel. The controller can control an extraction temperature within a range of 25 to 8O⁰C and an extraction time within a range of 20 min to 2 hours.

[49] In order to avoid contamination problems which may occur due to ultrasonic extraction processes or external factors, the extraction vessel may be advantageously made of stainless steel. For example, the extraction vessel may be made of preferably stainless-304, more preferably stainless-316, and most preferably stainless-316L.

[50] In order to provide a liquid extract of buckwheat sprouts, clean and safe water which is completely free of an organic solvent and is selected from distilled water, tap water, underground water and bottled water is preferably used as an extraction solvent. Bottled water or distilled water is more advantageous than tap water or underground water. More suitably, it is advantageous to use single-distilled water which is provided by a reverse osmosis (RO) system.

[51] When it is desired to provide a solid powder of buckwheat sprout extract, there is no particular limit to kinds of the extraction solvents that can be used. For example, the extraction solvent may be any of organic solvent-freewater, a mixture of water and organic solvent, and a water- free organic solvent. However, upon taking into consideration potential loss of thermal energy which may occur during the drying process for powderization of the buckwheat sprout extract after solvent extraction thereof, it may be advantageous to select a substantially water-free solvent.

[52] However, an extraction rate is very low or an extraction amount is insignificant when the active ingredients in the buckwheat sprout extract of the present invention are extracted with water or organic solvent alone. Therefore, it may be more advantageous to use a mixed solvent of the organic solvent with water which can satisfy various demands simultaneously with extractability of each active ingredient.

[53] When it is desired to use a mixed solvent, 100 parts by weight of the organic solvent may be mixed with preferably 5 to 35 parts by weight, more preferably 8 to 25 parts by weight, and most preferably 10 to 15 parts by weight of water. If the water content is less than 5 parts by weight, dissolution of water-soluble ingredients is poor. On the other hand, if the water content is more than 35 parts by weight, dissolution of water-soluble ingredients, e.g. highly polar organic materials, is very significant, but energy loss is disadvantageously high in the drying step for preparation of a powder. Therefore, the organic solvent and water should be mixed in a proper ratio as specified above.

[54] Even though the organic solvent used to extract the antioxidant substances and natural materials from buckwheat sprouts may be at least one selected from the group consisting of methylene chloride, ether, ethyl acetate, acetone, butanol, isopropanol (IPA: 2-propanol), ethanol, methanol and any combination thereof, it may be advantageous to select and use ethanol. This is because ethanol undergoes no layer separation due to high polarity when it is mixed with water, and is harmless to the human body even when a trace amount of the organic solvent is contained in the extract which is powderized by the drying process.

[55] The dehydration step in the present invention is intended to remove solids from the extracted buckwheat sprouts and may be carried out by any dehydration method of compression and centrifugation. The compression dehydration is primarily intended to remove solids from the extracted buckwheat sprouts, and the resulting cake of the dehydrated buckwheat sprouts may be advantageously reutilized as organic fertilizer or herbivorous animal feed. However, compression dehydration is more expensive than centrifugal dehydration and therefore is disadvantageous from an economic point of view.

[56] Compression dehydration may be advantageous for dehydration of a large volume of buckwheat sprout extract, whereas centrifugal dehydration is suitable for dehydration of a small volume of buckwheat sprout extract.

[57] The packaging step of the buckwheat sprout extract may be divided into a method of packaging an aqueous solution extracted from buckwheat sprouts in the form of an extract, and a method of drying an aqueous solution extracted from buckwheat sprouts and packaging the resulting powder.

[58] The former method for direct packaging of the aqueous extract must be carried out by vacuum packaging to extend a circulation period because the extract solution contains a large amount of organic materials. The latter packaging method of the powder after drying an aqueous solution of the extract may be carried out by any of hot-air drying, cold-air drying, freeze-drying and spray-drying using a drying machine.

[59] Hot-air drying may be carried out by heating and drying an extract with hot-air at a temperature of 60 to 15O⁰C. Due to a high heating temperature, the hot-air drying exhibits a very high drying rate and a highly effective removal rate of the organic solvent contained in the aqueous solution extracted by the solvent extraction method. However, this drying method may suffer from the risk of loss of volatile active ingredients which were extracted by the solvent. The cold-air drying is a method for powderization of an extract by heating at room temperature of 20 to 3O⁰C for a long period of time. This method has advantages associated with very low risk of volatilization and decomposition of volatile and non- volatile active ingredients which were extracted by the solvent, but exhibits disadvantages associated with very low economic efficiency due to a long period of heating time.

[60] Spray-drying is a method of obtaining a granular powder by drying an extract sprayed from the top with hot-air supplied at the bottom. This drying method has advantages such as a very rapid drying rate and high productivity via the feasibility of automatization, but exhibits a disadvantage associated with use of expensive equipment. The freeze-drying method involves pre-cooling of an extract material in a freezer at a temperature of -50 to -7O⁰C and then vacuum-drying the material in a freeze dryer. Therefore, the freeze-drying method advantageously exhibits substantially no loss of volatile and non- volatile active ingredients, thus providing active ingredients of buckwheat sprouts beneficial to the human body, and use of relatively inexpensive equipment. Accordingly, the freeze-drying method may be advantageous for drying and powderization of the extract.

[61] Even though the powderized extracts may be packaged under an air atmosphere, it is preferred to fill any inert gas selected from nitrogen (N ), argon (Ar) and helium (He) to maintain a long-term circulation period of the product. Most preferably, it is to fill inexpensive and inert nitrogen.

[62]

[63] EXAMPLES

[64] Now, the present invention will be described in more detail with reference to the following Examples. These examples are provided only for illustrating the present invention and should not be construed as limiting the scope and spirit of the present invention.

[65]

[66] Example 1

[67] After germination of buckwheat seeds at a temperature of 27⁰C for 7 days, the resulting buckwheat sprouts were homogeneously ground using a mixer, and 100 g of the ground buckwheat sprouts were precisely weighed in a 250 D beaker to which 20 D of triple-distilled water and 80 D of ethanol were added. The resulting mixture was introduced into a bath (ultrasonic cleaner) which is capable of providing ultrasonic waves at a temperature of 35⁰C. After extraction for 20 min and filtration, the filtrate was used as an analyte sample.

[68] Analysis was carried out as follows.

[69] Prior to quantitative analysis of individual ingredients, the extracted and filtered solution was examined for the retention time and mass of rutin, aspartic acid, glutamic acid and lysine peaks through liquid chromatography-mass spectrometry (LC-MS). Then, quantitative analysis of individual ingredients was carried out by liquid chromatography (LC) to thereby examine extraction rates of individual ingredients. For quantitative analysis, rutin, aspartic acid, glutamic acid and lysine were prepared at accurate concentrations of 0, 0.5, 1.0 2.0, 5.0, and 10.0 ppm to prepare standards, respectively, and the resulting standard solutions were subjected to LC/MS to thereby calculate peak areas with respect to the corresponding concentrations. A simple linear regression curve (standard curve) was plotted based on the thus-calculated values, and concentrations for the extract samples were calculated. Based on the results obtained, extraction rates of the extracts were compared and confirmed therebetween. LC/MS analysis conditions are given as follows.

[70]

[71] ► Column: Eclipse C18 (4.6 mm x 150 mm x 3.5 D)

[72] ► Eluent:

[73] Acetonitrile:Water (10 mM ammonium acetate)=30:70 Gradient (30% to 80%)

[74] ► Ionization: ESI (Negative Mode)

[75] ► Fragmentor: 150 V

[76]

[77] Comparative Example 1

[78] After germination of buckwheat seeds at a temperature of 27⁰C for 7 days, 100 g of the unground buckwheat sprouts were precisely weighed in a 250 D beaker to which 20 D of triple-distilled water and 80 D of ethanol were added. The resulting mixture was introduced into a bath (ultrasonic cleaner) which is capable of providing ultrasonic waves at a temperature of 35⁰C. After extraction for 20 min and filtration, the filtrate was used as an analyte sample. Analysis to confirm the extraction rate of individual ingredients was carried out in the same manner as in Example 1.

[79]

[80] Example 2

[81] After germination of buckwheat seeds at a temperature of 27⁰C for 7 days, the resulting buckwheat sprouts were homogeneously ground using a mixer, and 100 g of the ground buckwheat sprouts were precisely weighed in a 250 D beaker to which 100 D of triple-distilled water was added. The resulting mixture was introduced into a bath (ultrasonic cleaner) which is capable of providing ultrasonic waves at a temperature of 35⁰C. After extraction for 20 min and filtration, the filtrate was used as an analyte sample. Analysis to confirm the extraction rate of individual ingredients was carried out in the same manner as in Example 1.

[82]

[83] Comparative Example 2

[84] After germination of buckwheat seeds at a temperature of 27⁰C for 7 days, 100 g of the unground buckwheat sprouts were precisely weighed in a 250 D beaker to which 100 D of triple-distilled water was added. In order to prevent volatilization of the solvent during the heating process, a watch glass was placed on the beaker which was then heated on a hot plate at a temperature of 100⁰C for 1 hour. After extraction, cooling and filtration processes, the resulting filtrate was used as an analyte sample. Analysis to confirm the extraction rate of individual ingredients was carried out in the same manner as in Example 1.

[85]

[86] Example 3

[87] After germination of buckwheat seeds at a temperature of 27⁰C for 7 days, the resulting buckwheat sprouts were homogeneously ground using a mixer, and 100 g of the ground buckwheat sprouts were precisely weighed in a 250 D beaker to which 100 D of ethanol was added. The resulting mixture was introduced into a bath (ultrasonic cleaner) which is capable of providing ultrasonic waves at a temperature of 35⁰C. After extraction for 20 min and filtration, the filtrate was used as an analyte sample.

[88]

[89] Comparative Example 3

[90] After germination of buckwheat seeds at a temperature of 27⁰C for 7 days, 100 g of the unground buckwheat sprouts were precisely weighed in a 500 D round-bottom flask to which 100 D of ethanol was added. In order to prevent volatilization of the solvent occurring during the heating process, a cooling water-circulating condenser and a heating mantle were provided with the flask. After heating and extraction at a temperature of 7O⁰C for 1 hour, cooling and filtration, the resulting filtrate was used as an analyte sample. Analysis to confirm the extraction rate of individual ingredients was carried out in the same manner as in Example 1.

[91]

[92] Table 1 below shows extraction results of active ingredients for buckwheat sprouts extracted in Examples 1 to 3 and Comparative Examples 1 to 3.

[93]

[94] Table 1

[95] [96] As shown in Table 1, in the case of unground buckwheat sprouts, it was found that the extraction process should be carried out at a high temperature for a long time such that active ingredients in the buckwheat sprout stems can be dissolved into the solvent. When buckwheat sprouts were ground and dissolved by the solvent, an increased surface area of the buckwheat sprout material leads to a relative increase in a contact area with the solvent, thereby providing a very high extraction rate.

[97] Ultrasonic extraction according to the present invention at a low temperature for a short period of time showed an excellent recovery rate, whereas conventional long- term hot- water extraction exhibited a poor extraction rate. Further, only the limited active ingredients of buckwheat sprouts exhibited a high extraction rate upon use of water or organic solvent alone, whereas almost all the active ingredients of buckwheat sprouts exhibited a high extraction rate upon use of a mixed solution of water and organic solvent. These results represent that a polarity of the solvent should be modified depending upon a polarity of the compound, such that it is possible to provide a high extraction rate.

[98] Referring to drawings attached to the present application, FIGS. 1 and 2 show retention time versus total ion chromatogram and spectrum of an extract of the present invention, as measured by LC/MS, and FIGS. 3 and 4 show retention time versus total ion chromatogram and spectrum of a rutin standard for quantitative analysis of a rutin compound in an extract of the present invention, as measured by LC/MS.

[99] For quantitative analysis of the rutin compound in chemical materials extracted by an extraction method of the present invention, LC/MS total ion chromatogram and spectrum of rutin (MW; 610, C H O ) at the retention time of 3.733 min were first r 27 30 16 confirmed for the rutin standard, as shown in FIGS. 3 and 4. Then, as shown in FIGS. 1 and 2, the extract of the present invention was measured under the same conditions as in the standard compound.

[100] As a result, the retention time of the compound of the present invention was 3.427 min (FIG. 1, left, ion chromatogram), and the LC/MS spectrum (FIG. 2) also showed the same pattern as the standard compound, thus confirming a ratine compound having a retention time peak of about 3.5 min. As compared to a molecular weight of 610 of the rutin standard, the measured result of the compound of the present invention (FIGS. 2 and 4) exhibited a molecular weight which is 1 lower than a theoretical molecular weight of 610, due to use of a negative mode in LC/MS analysis of Example 1. If a positive mode is used, a value which is 1 higher than a theoretical molecular weight will be obtained.

[101] For quantitative analysis of the rutin compound after confirming that the retention time of the rutin standard compound and that of the rutin compound in the extract of the present invention have substantially the same value, peak areas with increasing concentrations of the rutin standard were plotted on a simple linear regression curve (standard curve). Thereafter, the thus -calculated value was compared with that of the sample which was measured by LC/MS analysis.

[102] From the experimental results of Examples in accordance with the present invention, it was confirmed that, in order to achieve high extraction rate and economic efficiency of the active ingredient contained in buckwheat sprouts, it is necessary to increase a surface area of a raw material to be extracted and apply ultrasonic waves to an extraction vessel to thereby simultaneously extract various ingredients at a high extraction rate. The present invention has been completed based on these findings.

[103] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[1] A method for solvent extraction of active ingredients from buckwheat sprouts, comprising: germinating buckwheat seeds to grow buckwheat sprouts (germination step); grinding the buckwheat sprouts to increase a specific surface area thereof, thereby improving a solvent extraction rate of buckwheat sprouts (grinding step); adding a solvent thereto to extract antioxidant substances and natural materials, followed by ultrasonic application (ultrasonic extraction step); removing solids of buckwheat sprouts extracted in the solvent (dehydration step); and packaging the dehydrated liquid material as a liquid extract.

[2] The method according to claim 1, wherein the liquid extract is dried to obtain a solid powder and the solid powder is then packaged.

[3] The method according to claim 1 or 2, wherein the buckwheat germination step includes dipping of buckwheat seeds in water for 12 to 36 hours, sieving the mixture, supplying to the buckwheat seeds an amount of water selected from distilled water, tap water, underground water and bottled water, at regular intervals of 6 to 8 hours, and growing the buckwheat seeds at a temperature of 20 to 38⁰C for 5 to 9 days to provide buckwheat sprouts.

[4] The method according to claim 1 or 2, wherein the buckwheat germination step includes dipping of buckwheat seeds in water for 12 to 36 hours, sieving the mixture, supplying to the buckwheat seeds an amount of water by hydroponic cultivation, at regular intervals of 6 to 8 hours, and growing the buckwheat seeds at a temperature of 20 to 38⁰C for 5 to 9 days to provide buckwheat sprouts.

[5] The method according to claim 4, wherein the irrigation water for hydroponic cultivation is water containing 0.8 to 2.0% by weight of nitrogen, 0.2 to 0.5% by weight of phosphorus, 0.5 to 2% by weight of potassium, 0.05 to 0.2% by weight of magnesium, 10 to 30 ppm of boron, 50 to 200 ppm of iron, 35 to 75 ppm of manganese, 10 to 25 ppm of zinc, 4 to 8 ppm of copper, and 0.05 to 0.2 ppm of molybdenum.

[6] The method according to claim 1 or 2, wherein the buckwheat sprout grinding step includes adding 10 to 60 parts by weight of water to buckwheat sprouts, based on 100 parts by weight of buckwheat sprouts, and grinding the mixture using a grinding mill at the rotational speed of 100 to 2,000 rpm.

[7] The method according to claim 1 or 2, wherein the extraction vessel used in the ultrasonic extraction step is made of stainless steel selected from stainless-304, stainless-316 and stainless-316L, one ultrasonic generator is installed per an extraction vessel internal area of 30 to 90 D, and the extraction process is carried out using automated equipment which can control an extraction temperature to be within a range of 25 to 8O⁰C and an extraction time to be within a range of 20 min to 2 hours. [8] The method according to claim 1 or 2, wherein the extraction solvent is water selected from distilled water, tap water, underground water and bottled water. [9] The method according to claim 1 or 2, wherein the extraction solvent is at least one organic solvent selected from methylene chloride, ether, ethyl acetate, acetone, butanol, isopropanol (IPA: 2-propanol), ethanol and methanol. [10] The method according to claim 1 or 2, wherein the extraction solvent is selected from organic solvents of claim 9, and the extraction process is carried out using a mixed solvent of 5 to 35 parts by weight of water with 100 parts by weight of the organic solvent. [11] A liquid extract of buckwheat sprouts comprising active ingredients, which is prepared by the method of claim 1. [12] A powder extract of buckwheat sprouts comprising active ingredients, which is prepared by the method of claim 2. [13] The powder extract according to claim 12, wherein the extract is provided with filling of inert nitrogen (N ) gas.