Method for producing rutin extract derived from buckwheat stalks and leaves and rutin aroma complex extract derived from buckwheat

Abstract

[Challenge] To extract rutin from buckwheat stalks, leaves, and immature grains in large quantities and stably without compromising flavor or aroma. [Solution] Buckwheat stalks and leaves, as well as immature buckwheat grains, are harvested before and during flowering. Within 4 hours of harvesting, the buckwheat is blanched in hot water at 90°C to 100°C for 60 to 180 seconds to deactivate the enzymes. Then, the rutin component is extracted in hot water at 100°C to 120°C for 8 to 15 minutes while adding cyclodextrin to maintain the extract concentration at 1 to 3%.

Description

Technical Field

[0001] The present invention relates to a method for stably extracting a large amount of rutin from the stems and leaves of common buckwheat (Fagopyrum esculentum), and a method for producing a rutin-aroma composite extract that retains the flavor of buckwheat by mixing an aroma extract derived from unripe buckwheat seeds into the rutin extract.

Background Art

[0002] Rutin, which is a type of polyphenol contained in buckwheat, has a strong antioxidant power and has attracted attention as a health supplement food and a raw material for cosmetics. However, in the conventional production method for extracting rutin from buckwheat, in the process from harvesting buckwheat seeds to extracting rutin, since enzyme inactivation by blanching is not performed, the rutin component rapidly decreases before entering the extraction process, and in reality, almost no rutin component derived from buckwheat that contributes to health is contained. Also, although there is a demand for rutin in a wide variety of products, except for tartary buckwheat, rutin derived from common buckwheat has hardly been supplied.

[0003] On the other hand, although it has been academically recognized that in addition to seeds, rutin is contained in the stems and leaves of buckwheat at the time of flowering, the cases of extracting rutin from buckwheat stems and leaves are very few, and only a few cases of extracting buckwheat extract (rutin) used as a raw material for buckwheat beverages have been disclosed (see Patent Document 1).

[0004] According to the above Patent Document 1, after harvesting, buckwheat stems and leaves are washed with water, dehydrated, cut into 3 to 5 mm pieces, then dried under reduced pressure at 60°C for 16 hours, further roasted at 90°C for 8 minutes, and then subjected to an extraction process with hot water at 95 to 98°C. If there are processes of cutting, drying, and roasting before such an extraction process, it is assumed that the rutin component will easily be enzymatically decomposed and flow out from the raw material buckwheat stems and leaves during this period.

[0005] The following points can be considered as problems in extracting rutin from buckwheat stems and leaves and problems in extracting aroma components from unripe buckwheat seeds. 1. Due to the action of enzymes (especially polyphenol oxidase) present in the stems and leaves, rutin decomposes over time after harvest. Therefore, it is necessary to inactivate these enzymes to stop the decomposition of rutin. 2. Since rutin becomes unstable with heat, it is necessary to determine the appropriate hot water temperature for extraction. 3. In Japan, buckwheat production accounts for only about 10% of demand, with 90% being imported from overseas. The rutin content in buckwheat stems and leaves is very low, and the aroma and flavor are often significantly deteriorated. Furthermore, the buckwheat-specific aromatic components (volatile phenols, pyran compounds, etc.) contained in immature grains are prone to volatilization and oxidation, and the flavor deteriorates over time and storage temperature. Therefore, in order to effectively utilize domestically produced buckwheat raw materials, it is necessary to efficiently extract large quantities of rutin from the stems, leaves, and immature grains of ordinary buckwheat, which have not been used until now, without compromising the aroma and flavor. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2008-11759 (paragraphs 0031-0034, Figure 1) [Overview of the project] [Problems that the invention aims to solve]

[0007] This invention was made to solve the above-mentioned problems, and its purpose is to address the following technical issues. 1. To stably extract large quantities of rutin from buckwheat stalks and leaves. 2. To extract, retain, and stabilize aromatic components from immature buckwheat grains, thereby ensuring good aroma and flavor. 3. Provide these aromatic complex extracts, consisting of buckwheat stem and leaf extracts and buckwheat immature seed aroma extracts, either individually or in combination, in a form suitable for food and beverages. [Means for solving the problem]

[0008] The present invention provides a method for producing rutin extract derived from buckwheat stalks and leaves, which is a method for stably and abundantly extracting rutin from buckwheat. This method involves harvesting buckwheat stalks and leaves before and during flowering, immediately after harvesting (within 4 hours) blanching them in hot water at 90°C to 100°C for 60 to 180 seconds to inactivate enzymes, extracting the rutin component in hot water at 100°C to 120°C for 8 to 15 minutes while adding cyclodextrin to maintain the extract concentration at 1 to 3%, and then concentrating under reduced pressure. Furthermore, the present invention provides a method for producing a rutin aroma complex extract derived from buckwheat, which involves mixing a rutin extract derived from buckwheat stalks and leaves with an aroma extract derived from buckwheat immature grains, which are produced by blanching and extracting these immature grains under the same conditions as the method for producing the rutin extract derived from buckwheat stalks and leaves, in a proportion suitable for the intended use. [Effects of the Invention]

[0009] According to the present invention, the following effects can be obtained. 1. Rutin degradation can be suppressed by enzyme inactivation through blanching. 2. By setting the appropriate time and temperature for extraction, the amount of rutin extracted can be increased. 3. Cyclodextrin inclusion prevents the volatilization and oxidation of aroma components. 4. The aroma characteristics remain stable over the long term, and the characteristic grassy smell of buckwheat is reduced. 5. We can provide a buckwheat-derived rutin aroma complex extract (semi-finished product) with excellent preservation, usability, and distribution properties. [Brief explanation of the drawing]

[0010] [Figure 1] This is a manufacturing process diagram showing the steps for producing a rutin aroma complex extract from buckwheat stalks and leaves and immature buckwheat grains as shown in this embodiment. [Figure 2] This is a diagram illustrating the process for producing rutin extract from buckwheat stalks and leaves. [Figure 3] This is a diagram illustrating the process for producing aromatic extracts from immature buckwheat grains. [Figure 4]It is a process diagram for manufacturing a rutin-aroma composite extract from a rutin-containing extract and an aroma extract. [Figure 5] It is a table showing the remaining rutin amounts in buckwheat stems and leaves with or without branching compared. [Figure 6] It is a table showing the relationship between the hot water temperature and the color and taste judgment in the branching process. [Figure 7] It is a table showing the relationship between the processing time and the color and taste judgment in the branching process. [Figure 8] It is a table showing the relationship between the extraction temperature and the remaining rutin amount in the extraction process. [Figure 9] It is a table showing the relationship between the extraction time and the remaining rutin amount in the extraction process. [Figure 10] It is a table showing the aroma and flavor judgment in the extraction process with or without cyclodextrin addition compared. Mode for Carrying Out the Invention

[0011] Hereinafter, the manufacturing method of the best embodiment of the present invention will be described based on FIGS. 1 to 10. However, the present invention is not limited to the following embodiments. Here, FIG. 1 is a manufacturing process diagram showing the process of manufacturing a rutin-aroma composite extract from buckwheat stems and leaves and buckwheat immature fruits of the present embodiment, and includes a process of manufacturing a rutin extract from buckwheat stems and leaves (FIG. 2), a process of manufacturing an aroma extract from buckwheat immature fruits (FIG. 3), and a process of manufacturing a rutin composite extract from the rutin extract and the aroma extract (FIG. 4).

[0012] (Process of manufacturing a rutin extract from buckwheat stems and leaves) The process of extracting a large amount and stably extracting rutin components from buckwheat stems and leaves of the present invention uses at least one of buckwheat stems and leaves harvested immediately before flowering or during the morning of flowering as raw materials. As shown in FIG. 2, it consists of eight processes: (1) harvesting, (2) branching, (3) storage, (4) extraction, (5) filtration, (6) concentration, (7) sterilization, and (8) freezing storage.

[0013] (Harvesting and Branching) The purpose of blanching is to inactivate the rutin-degrading enzyme by blanching (hot water treatment) so that rutin in buckwheat stems and leaves does not disappear during the storage period until the extraction process, to suppress the degradation of rutin, to increase the residual amount of rutin before the extraction process, and to improve the rutin extraction rate from buckwheat stems and leaves in the extraction process. In the blanching process, since it is necessary to cut the raw buckwheat stems and leaves to a length of 15 cm to 20 cm according to the size of the production container (autoclave), it is necessary to blanch within 4 hours after harvesting so that rutin is not decomposed.

[0014] Figure 5 is a table showing the effect of suppressing rutin degradation by blanching, comparing with the case without blanching using the rutin residual rate in buckwheat stems and leaves as an index. The sample with blanching shown in Figure 5 is a sample obtained by blanching buckwheat stems and leaves harvested immediately before flowering in hot water at 90°C for 120 seconds and then storing them at 20°C for 180 days. The sample without blanching for comparison is a sample after 180 days of storage harvested in the same field as the sample with blanching and stored under the same conditions. Here, both samples used for the quantitative analysis of rutin were 5 g, and the measurement was performed using liquid chromatography. The rutin residual rate shown in the table of Figure 5 is the residual amount of rutin after blanching with respect to the rutin content (52 mg) in 5 g of the sample before blanching in the case of blanching, and the residual amount of rutin after 180 days of storage with respect to the rutin content (52 mg) in 5 g of the sample immediately after raw material harvesting in the case of no blanching. From Figure 5, it was confirmed that by blanching, more than twice as much rutin remains compared to without blanching, and blanching is effective in suppressing rutin degradation.

[0015] Figure 6 is an experiment to determine the appropriate temperature for enzyme inactivation by blanching on buckwheat stems and leaves immediately after harvesting. Using samples stored for 180 days, with a constant immersion time of 120 seconds and the temperature changed, the color and taste were used as indices for evaluation. From Figure 6, it was judged that the appropriate temperature for blanching is 90°C to 100°C because the color and taste are overall light when the temperature is below 90°C, and rutin degradation progresses and the bitterness increases when the temperature exceeds 110°C.

[0016] Figure 7 shows an experiment to determine the optimal time for enzyme deactivation by blanching in buckwheat stalks and leaves immediately after harvest. Samples stored for 180 days were used, and the immersion temperature was kept constant at 100°C. The color and taste were evaluated as indicators when the blanching time was varied. From Figure 7, it was determined that if the blanching time was less than 60 seconds, uneven deactivation occurred, and if it exceeded 180 seconds, enzyme deactivation was possible, but rutin decomposition progressed and bitterness increased. Therefore, the optimal blanching time was determined to be between 60 and 180 seconds.

[0017] (extraction) In the extraction process, the buckwheat stalks and leaves, which had been blanched and then frozen, were further cut into 1cm to 2cm lengths. These cuts were then immersed in a tank (pressure vessel) filled with hot water, and extraction was carried out under appropriate temperature and time conditions. Cyclodextrin was added to further prevent the volatilization and oxidation of aromatic components. The experimental results obtained to determine the optimal conditions for these extraction operations are shown in Figures 8 and 9. The sample used for the quantitative analysis of rutin was 5g, and the measurement was performed using liquid chromatography.

[0018] Figure 8 shows the results of an experiment to determine the optimal pressurized hot water temperature for rutin extraction from buckwheat stalks and leaves that had been blanched immediately after harvest to deactivate enzymes. Here, the amount of rutin remaining was measured while varying the extraction temperature, with the extraction time kept constant at 10 minutes. From Figure 8, it was determined that rutin extraction decreased below 90°C, and rutin decomposition progressed above 130°C. Therefore, based on the rutin remaining rate, the optimal pressurized hot water temperature was determined to be between 100°C and 120°C.

[0019] Figure 9 shows the results of an experiment to determine the optimal extraction time for rutin extraction in buckwheat stalks and leaves that had been blanched immediately after harvest to deactivate enzymes. Here, the amount of rutin remaining was measured while the extraction temperature was kept constant at 110°C and the extraction time was varied. From Figure 9, it was determined that the rutin extraction rate decreased if the extraction time was less than 4 minutes, and rutin decomposition progressed if it was more than 20 minutes, so the optimal extraction time was determined to be between 8 and 15 minutes.

[0020] (filtration, concentration, sterilization, frozen storage) After the extraction process, the solution is concentrated under reduced pressure at 50°C or below (Brix level 30% or less), then sterilized, and stored frozen at -20°C.

[0021] (Process for producing aromatic extracts from unripe fruit) The present invention's process for efficiently extracting aromatic components from immature buckwheat grains consists of nine steps, as shown in Figure 3: (1) harvesting, (2) sorting and recovery, (3) blanching, (4) preservation, (5) extraction, (6) filtration, (7) concentration, (8) sterilization, and (9) freezing and preservation. Except for the addition of the sorting and recovery step after the harvesting step, it is identical to the manufacturing method for extracting rutin from buckwheat stalks and leaves. The blanching conditions (temperature, time) and extraction conditions (temperature, time, cyclodextrin addition) are also all the same. The only difference is the sorting and recovery step, in which, after drying the harvested buckwheat grains, unused immature grains that cannot be used as buckwheat grains are sorted and recovered and used as raw materials for aromatic extraction.

[0022] Figure 10 is a table showing the aroma and flavor in the process of extracting aroma components from immature buckwheat grains, comparing the presence and absence of cyclodextrin. From Figure 10, it was confirmed that adding 1-3% cyclodextrin to the extract stabilizes and encapsulates the aroma and flavor, preserving them over a long period. It was also confirmed that the extract without cyclodextrin had a bitter taste and an oxidized odor. Immature buckwheat grains that had been blanched to inactivate the enzymes were used as samples.

[0023] (Process for producing a rutin complex extract from rutin extract and aroma extract) The process for manufacturing rutin extract derived from buckwheat consists of three steps: (1) freeze-thawing, (2) mixing, and (3) semi-finishing. The rutin extract derived from buckwheat stalks and leaves and the aroma extract derived from immature buckwheat seeds, which are stored frozen at -20°C, are thawed separately and mixed in appropriate ratios according to the intended use (mixing step), before moving on to the semi-finishing step. In this step, the process varies depending on the intended use, including freeze-pulverization, freeze-drying, shaping, and capsule production. For example, when used in buckwheat noodles, a powder containing 20mg to 40mg of rutin per serving is added, resulting in semi-finishing by freeze-drying.

[0024] (Specific examples of the effects of the invention) The method of the present invention allows for the extraction of buckwheat stalks, leaves, and immature grains under optimal conditions, and by mixing the two, the following effects, which could not be obtained with conventional buckwheat flour, can be achieved. Furthermore, the use of buckwheat-derived rutin can contribute to a wide range of antioxidant products. 1. Increase in rutin production The rutin content of buckwheat stalks and leaves before and during flowering is 3-6% per 10 ares, which corresponds to approximately 8 times the rutin production of Tartary buckwheat and 36 times that of ordinary buckwheat. By concentrating the extract according to the present invention to a rutin extract concentration of 30% or less, this product can be easily utilized in a wide range of products. 2. Soba noodles with a high rutin content offer a dramatic improvement in health. By concentrating the extract according to the present invention to 300% by weight and adding it to buckwheat flour for buckwheat noodles, a rutin-enhancing effect of 20-40 mg, which is more than four times that of ordinary buckwheat flour, can be easily obtained. 3. Retention of aromatic components and imparting of flavor. Buckwheat flour that has not had its enzymes deactivated will lose its aroma and flavor over time and with temperature fluctuations. By mixing in an aroma complex extract derived from immature buckwheat grains, a refreshing buckwheat aroma can be imparted. 4. Improved processing suitability and stability Blanching inactivates enzymes, which inhibits the breakdown of rutin, resulting in high shelf life in both liquid and powder forms. [Industrial applicability]

[0025] The rutin aroma complex extract obtained by the present invention can be widely applied to the following uses. 1. Buckwheat flour additives By adding 2-6% by weight to buckwheat flour for noodle making (20-40 mg per serving of soba), the rutin content can be increased to more than three times the conventional amount, enhancing the functionality of the food and improving its flavor. 2. Health supplements It can provide rutin in various forms such as powder, granules, or crushed form, delivering a daily intake of 20-40 mg. 3.Tea and beverages By incorporating it into beverages and powdered tea, it can impart a refreshing aroma and antioxidant properties. 4. Cosmetics, topical preparations It can be used as an ingredient in beauty serums, creams, and other products that take advantage of its antioxidant and anti-glycation properties. This technology effectively utilizes the stalks, leaves, and immature grains of buckwheat, which were previously unused, and contributes to adding value to domestic agricultural products, promoting regional development, and advancing the functional materials industry.

Claims

1. A manufacturing method for extracting a large amount of rutin from buckwheat stalks and leaves in a stable manner, A method for producing rutin extract derived from buckwheat stalks and leaves, characterized by immediately blanching the buckwheat stalks and leaves in hot water at 90°C to 100°C for 60 to 180 seconds after harvesting to inactivate the enzymes, and then extracting the rutin component in hot water at 100°C to 120°C for 8 to 15 minutes while adding cyclodextrin to maintain the concentration of the extract at 1 to 3%.

2. A method for producing a rutin-derived rutin-aroma complex extract from buckwheat by mixing a rutin-containing extract derived from buckwheat stalks and leaves, extracted by the manufacturing method described in claim 1, with unused immature buckwheat grains that cannot be used as buckwheat grains, and then blanching and extracting the immature buckwheat grains under the same conditions as the manufacturing method described in claim 1 to produce an aroma extract derived from immature buckwheat grains.

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