Mulberry leaf extract and process for producing the same

Abstract

To provide a mulberry leaf extract reduced in unpleasant taste and unpleasant odor, and to provide a method for producing the mulberry leaf extract.SOLUTION: A mulberry leaf extract having effectively reduced unpleasant taste and unpleasant odor can be obtained through a first step of subjecting mulberry leaves to extraction treatment with water containing 0 to 30 mass% of a lower alcohol to obtain an extract having a ratio (300nm / A300) of absorbance A320 at wave length 320nm to absorbance A300 at wave length A320 of 0.97 or less, and a second step of subjecting the extract obtained in the first step to active carbon treatment.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a mulberry leaf extract having reduced unpleasant tastes (bitterness, astringency) and unpleasant odors (grassy, ​​fishy odors), and a method for producing the same. [Background technology]

[0002] A sudden rise in blood glucose levels after a meal is said to stimulate the production of reactive oxygen species, causing oxidative stress in blood vessels, accelerating arteriosclerosis and leading to cardiovascular disease. Furthermore, in recent years, it has been suggested that a sudden rise in blood glucose levels after a meal can lead to cancer and dementia, making postprandial blood glucose control an important issue for achieving healthy longevity.

[0003] Inhibition of small intestinal disaccharidase is one way to suppress a rapid rise in blood glucose levels after a meal. Mulberry leaves have a strong inhibitory effect on small intestinal disaccharidase and are known as an effective ingredient for controlling postprandial blood glucose levels, and mulberry leaf extract is used in functional foods.

[0004] Various methods for producing mulberry leaf extract have been investigated. For example, Patent Document 1 discloses that a mulberry leaf extract containing a large amount of stabilized quercetin glycoside or kaempferol glycoside can be obtained by heat-treating mulberry leaves in the presence of an acid. Furthermore, Patent Document 2 discloses that an extract in which the reduction of polyphenol components is suppressed can be obtained by washing, freezing, and then extracting the lyophilized mulberry leaves with a hydrophilic organic solvent.

[0005] However, conventional mulberry leaf extracts have the inherent drawbacks of having an unpleasant taste (bitterness / astringency) and an unpleasant odor (grassiness / fishy odor), making them unsuitable for daily consumption. Therefore, there is a need for a mulberry leaf extract that has the inhibitory activity of small intestinal disaccharidase, has no unpleasant taste or odor, and can be added to general foods without compromising their commercial value. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-282632 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-147605 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a mulberry leaf extract having reduced unpleasant taste and odor, and a method for producing the same. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems, and have found that by extracting mulberry leaves with water containing 0 to 30% by mass of a lower alcohol, the absorbance A 300 Absorbance A at a wavelength of 320 nm 320 The ratio (A 320 / A 300 They have found that a mulberry leaf extract in which unpleasant taste and odor are effectively reduced can be obtained by carrying out a first step of obtaining an extract having an n-hexanal concentration of 0.97 or less, and a second step of treating the extract obtained in the first step with activated carbon. They have also found that the mulberry leaf extract thus obtained has an n-hexanal concentration of 0.75 ppb or less as measured by gas chromatography mass spectrometry (GC / MS) under specified conditions. The present invention was completed through further investigation based on these findings.

[0009] That is, the present invention provides the following aspects. Item 1. A method for producing a mulberry leaf extract, comprising: Mulberry leaves were extracted with water containing 0 to 30% by mass of lower alcohol, and the absorbance A 300 Absorbance A at a wavelength of 320 nm 320 The ratio (A 320 / A 300 A first step of obtaining an extract having a value of 0.97 or less; A second step of subjecting the extract obtained in the first step to activated carbon treatment, A production method comprising the above. Item 2. The mulberry leaves subjected to extraction treatment in the first step are pretreated, The pretreatment is steam heat treatment carried out under temperature conditions of 60°C or higher, and when the maximum temperature reached does not exceed 90°C, the total treatment time, or when the maximum temperature reached exceeds 90°C, the treatment time until reaching 90°C, is carried out such that the integrated value of the heating temperature (°C) and the heating time (seconds) in the temperature range of 60 - 90°C is 1000°C·seconds or more. The production method according to Item 1. Item 3. The lower alcohol is ethanol. The production method according to Item 1 or 2. Item 4. A mulberry leaf extract obtained by the production method according to any one of Items 1 to 3. Item 5. A mulberry leaf extract having an n-hexanal concentration of 0.75 ppb or less measured under the following measurement conditions. <Measurement conditions for n-hexanal concentration> Dilute the mulberry leaf extract with water so that the α-glucosidase inhibitory activity becomes 5000 IU / ml. Then, measure the n-hexanal concentration of the diluted solution by gas chromatography-mass spectrometry using the absolute calibration curve method. The α-glucosidase inhibitory activity unit "IU" is the amount of inhibitor determined by the following method. First, add an appropriate amount of α-glucosidase crude enzyme solution derived from rat small intestine to an aqueous maltose solution with a final concentration of 100 mM, hold at 37°C for 40 minutes, and set the reaction conditions so that 115 - 125 mg / dL of glucose is produced. In 1 ml of this reaction system, the unit of inhibitory activity that can inhibit 50% of the activity of α-glucosidase derived from rat small intestine is defined as 1 IU. The α-glucosidase crude enzyme solution is prepared by suspending rat small intestine acetone powder in 0.1 M phosphate buffer (pH 7.0) to a concentration of 10% by mass and using the centrifuged supernatant. Item 6. The mulberry leaf extract according to Item 5, wherein when diluted with water so that the α-glucosidase inhibitory activity becomes 5000 IU / ml and filtered using a 0.45 μm membrane filter, the absorbance at a wavelength of 405 nm of the diluted solution is 0.300 or less. Item 7. A food or drink containing the mulberry leaf extract according to any one of Items 4 to 6. [Effects of the Invention]

[0010] The mulberry leaf extract of the present invention has reduced unpleasant tastes (bitterness, astringency) and unpleasant odors (grassy, ​​fishy odors) unique to mulberry leaves, has excellent taste, and does not adversely affect the taste when added to foods, making it possible to provide foods, etc., with excellent taste for suppressing postprandial blood glucose elevation. Furthermore, the mulberry leaf extract of the present invention has the advantage of being suppressed in coloration, and does not adversely affect the appearance when added to foods, etc., and therefore there are no restrictions on use in terms of food appearance. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1. Manufacturing method of mulberry leaf extract The method for producing a mulberry leaf extract of the present invention is characterized by comprising the following steps 1 and 2. The method for producing a mulberry leaf extract of the present invention will be described in detail below. First step: Extract mulberry leaves with water containing 0 to 30% by mass of lower alcohol, and measure the absorbance A at a wavelength of 300 nm. 300 Absorbance A at a wavelength of 320 nm 320 The ratio (A 320 / A 300 ) is 0.97 or less to obtain an extract. Second step: The extract obtained in the first step is subjected to activated carbon treatment.

[0012] [1st step] In the first step, mulberry leaves are extracted with water containing 0 to 30% by mass of a lower alcohol, and the absorbance A 300 Absorbance A at a wavelength of 320 nm 320 The ratio (A 320 / A 300 ) is 0.97 or less.

[0013] ·Extraction raw materials The mulberry leaves used as the raw material for extraction are leaves of mulberry species belonging to the genus Morus in the family Moraceae. There are no particular limitations on the variety, place of origin, harvest time, etc. of the mulberry leaves used as the raw material for extraction.

[0014] The mulberry leaves used as the extraction raw material may be subjected to processing such as shredding or crushing.

[0015] Pretreatment of raw materials for extraction In the present invention, the mulberry leaves used as the extraction material are extracted by the extraction process described below to obtain a ratio (A 320 / A 300 It is important to carry out pretreatment to obtain an extract with a ratio (A) of 0.97 or less. Even if mulberry leaves are subjected to the extraction process described below without pretreatment, the ratio (A) 320 / A 300 ) below 0.97.

[0016] Ratio (A 320 / A 300 A suitable example of pretreatment for obtaining an extract having a value of 0.97 or less is steam treatment of mulberry leaves at 60°C or higher, where the integral of the heating temperature (°C) and heating time (seconds) in the temperature range of 60 to 90°C (hereinafter referred to as "integral value") is obtained during the entire treatment time if the maximum temperature does not exceed 90°C, or during the treatment time until the maximum temperature exceeds 90°C. 60 ~ 90 One method is to perform steaming so that the temperature (A) is 1000°C·sec or higher. By performing steaming under these specific conditions, the ratio (A) can be increased by the extraction process described below. 320 / A 300 ) can be efficiently obtained.

[0017] In the present invention, "steaming treatment" refers to a treatment in which the material is heated in steam.

[0018] In the present invention, "integral value 60 ~ 90 °C" is the area of ​​the curve showing the change in heating temperature (°C) over time (seconds) in the temperature range of 60 to 90°C. However, the integral value 60 ~ 90When the maximum temperature reached in the steaming treatment is 90°C or less, °C is the integral of the heating temperature (°C) and heating time (seconds) in the temperature range of 60 to 90°C, calculated for the entire range of the steaming treatment. When the maximum temperature reached in the steaming treatment exceeds 90°C, °C is the integral of the heating temperature (°C) and heating time (seconds) in the temperature range of 60 to 90°C, calculated for the range up to when 90°C is reached. In other words, when the maximum temperature reached in the steaming treatment exceeds 90°C, even if the temperature range of 60 to 90°C is passed through during cooling after reaching the temperature range above 90°C, the thermal history in the temperature range of 60 to 90°C experienced after reaching above 90°C is the integral value. 60 ~ 90 °C. Although a restrictive interpretation is not desired, it is presumed that some kind of enzymatic reaction that contributes to the reduction of unpleasant tastes and odors occurs during steam heat treatment in the temperature range of 60 to 90°C, and that once subjected to a heat history of 90°C or higher, the activity of the enzyme is reduced or inactivated, and even if the temperature is returned to the 60 to 90°C range, the enzymatic reaction that contributes to the reduction of unpleasant tastes and odors will no longer proceed.

[0019] For example, if the maximum temperature reached during steam treatment is within the range of 60 to 90°C, and the heating conditions to the maximum temperature α°C are set as follows: the heating rate is a constant β°C / second, the time required to raise the temperature from the point at which 60°C is reached during heating to the maximum temperature α°C is t1 seconds; the time required from the point at which 60°C is reached during heating to the completion of holding at the maximum temperature α°C is t2 seconds; and the temperature decreasing conditions from the maximum temperature α°C to 60°C are set as follows: the heating rate is a constant γ°C / second, and the time required from the point at which 60°C is reached during heating to lowering the temperature from the maximum temperature α°C to 60°C is t3 seconds, then the integral of the heating temperature (°C) and heating time (seconds) in the temperature range of 60 to 90°C is the sum of the "integral of the temperature (°C) and time (seconds) during heating," "the integral of the temperature (°C) and time (seconds) during heating," and "the integral of the temperature (°C) and time (seconds) during heating," which are calculated using the following formula:

number

[0020] Furthermore, for example, if the maximum temperature reached during steam treatment exceeds 90°C, and the temperature rise conditions up to the maximum temperature α°C are set at a constant temperature rise rate of β°C / second, and the time required for the temperature to rise from the point at which 60°C is reached to 90°C during temperature rise is set to t1 seconds, then the integral of the heating temperature (°C) and heating time (seconds) in the temperature range of 60 to 90°C will be the "integral of the temperature (°C) and time (seconds) during temperature rise from 60°C to 90°C," which is calculated using the following formula:

number

[0021] Integrated value by vapor heat treatment 60 ~ 90 The temperature should be 1000°C·sec or more, but from the viewpoint of obtaining a mulberry leaf extract in which unpleasant taste and odor are more effectively reduced, the integral value 60 ~ 90 The temperature is preferably 1000 to 100,000°C·sec, more preferably 1000 to 50,000°C·sec, even more preferably 1000 to 10,000°C·sec, still more preferably 1000 to 6,500°C·sec, and particularly preferably 1,800 to 6,300°C·sec. Conventionally, mulberry leaves have been subjected to steaming treatment during the production of mulberry leaf tea, and in the steaming treatment during the production of mulberry leaf tea, the temperature is rapidly raised to 95°C or higher for the purpose of enzyme inactivation, and the above-mentioned integral value 60 ~ 90 °C is significantly less than 1000 °C·sec.

[0022] For specific conditions of vapor heat treatment, see the integral value 60 ~ 90The temperature may be appropriately set so that the temperature falls within the above range. For example, the maximum temperature reached by the steaming treatment is about 60 to 150°C, preferably about 60 to 120°C, more preferably about 60 to 100°C, and even more preferably about 60 to 95°C. Specific conditions for the steaming treatment include conditions in which the temperature is increased at a rate of about 0.01 to 1000°C / sec, the maximum temperature reached is about 60 to 150°C, and this is maintained for about 1 to 86,400 seconds, followed by rapid cooling to less than 60°C; preferably conditions in which the temperature is increased at a rate of about 0.1 to 500°C / sec, the maximum temperature reached is about 60 to 120°C, and this is maintained for about 1 to 43,200 seconds, followed by rapid cooling to less than 60°C; more preferably conditions in which the temperature is increased at a rate of about 0.1 to 300°C / sec, the maximum temperature reached is about 60 to 100°C, and this is maintained for about 1 to 1,440 seconds, followed by rapid cooling to less than 60°C; and even more preferably conditions in which the temperature is increased at a rate of about 0.5 to 50°C / sec, the maximum temperature reached is about 60 to 95°C, and this is maintained for about 10 to 60 seconds, followed by rapid cooling to less than 60°C.

[0023] The steam-treated mulberry leaves may be subjected to extraction treatment as they are, or may be subjected to extraction treatment after drying, if necessary.

[0024] Extraction solvent In the first step, water containing 0 to 30% by mass of a lower alcohol is used as the extraction solvent. That is, in the first step, water or a water-containing lower alcohol with a lower alcohol content of 30% by mass or less is used as the extraction solvent. By using an extraction solvent with such a composition, the ratio (A 320 / A 300 ) can be obtained as an extract having a value of 0.97 or less.

[0025] The lower alcohol is a monohydric alcohol having 1 to 5 carbon atoms, and specific examples thereof include ethanol, propanol, butanol, pentanol, etc. These lower alcohols may be used alone or in combination of two or more. Among these lower alcohols, ethanol is preferred.

[0026] The content of lower alcohol in the extraction solvent may be 0 to 30% by mass, preferably 0 to 20% by mass, more preferably 0 to 10% by mass, from the viewpoint of obtaining a mulberry leaf extract with reduced coloration while further reducing unpleasant taste and odor.

[0027] Extraction process The extraction treatment is carried out by immersing the pretreated mulberry leaves in an extraction solvent and stirring as necessary.

[0028] In the extraction process, the amount of mulberry leaves to be immersed in the extraction solvent is not particularly limited, but for example, the amount of mulberry leaves to be immersed in 1 L of solvent should be set at about 1 to 1000 g, preferably about 50 to 500 g, and more preferably about 100 to 300 g, in dry weight terms.

[0029] The temperature conditions during extraction are not particularly limited, but may be, for example, about 0 to 100°C, preferably about 40 to 100°C, more preferably about 60 to 100°C, and even more preferably about 80 to 100°C.

[0030] The extraction treatment conditions are not particularly limited, but may be, for example, about 1 to 1440 minutes, preferably about 10 to 300 minutes, and more preferably about 30 to 120 minutes.

[0031] The extract obtained After the extraction process, the liquid fraction is collected by solid-liquid separation to obtain a liquid extract. The extract obtained under the above-mentioned processing conditions has an absorbance A of 300 nm. 300 Absorbance A at a wavelength of 320 nm 320 The ratio (A 320 / A 300 ) is 0.97 or less, and by subjecting the extract to the second step described below, a mulberry leaf extract with reduced unpleasant taste and odor can be obtained.

[0032] The ratio of the extract obtained by the extraction treatment in the first step (A 320 / A 300) is 0.97 or less, the extract is diluted with water to a Brix of 0.035, and the absorbance A of the diluted solution at a wavelength of 300 nm is 300 and absorbance A at a wavelength of 320 nm 320 It can be determined by measuring the absorbance A 300 and absorbance A 320 Round off the measured value to the third decimal place, calculate the significant figure to the second decimal place, and calculate the absorbance A 300 and absorbance Degree A 320 By calculating the ratio of 320 / A 300 ) is required.

[0033] The ratio of the extract obtained in the first step (A 320 / A 300 ) is sufficient if it is 0.97 or less, but from the viewpoint of obtaining a mulberry leaf extract in which unpleasant taste and unpleasant odor are more effectively reduced, the ratio (A 320 / A 300 ) is preferably 0.96 or less, more preferably 0.95 or less, and even more preferably 0.90 or less. 320 / A 300 The lower limit of such a ratio (A) is not particularly limited, but may be, for example, 0 or more, 0.50 or more, 0.70 or more, 0.80 or more, or 0.85 or more. 320 / A 300 An extract satisfying the above requirements can be obtained by appropriately setting the pretreatment conditions of the mulberry leaves, the composition of the extraction solvent, the extraction conditions, etc. within the above-mentioned ranges.

[0034] [Second process] The second step is a step of subjecting the extract obtained in the first step to an activated carbon treatment.

[0035] The type of activated carbon used in the activated carbon treatment is not particularly limited, and any type commonly used in the treatment of food materials may be used. Examples of raw materials for activated carbon include coconut shells, wood, and coal. Among these, wood is preferred.

[0036] The activated carbon may be any of activated carbons that have been chemically activated with, for example, zinc chloride, phosphoric acid, sulfuric acid, calcium chloride, sodium hydroxide, potassium hydroxide, etc., and activated carbons that have been gas-activated with water vapor, carbon dioxide gas, oxygen gas, combustion exhaust gas, mixed gases thereof, etc. Among these, activated carbons that have been chemically activated are preferred.

[0037] The activated carbon treatment may be carried out by contacting the extract obtained in the first step with activated carbon, and may be carried out, for example, by a batch method in which activated carbon is added to the extract obtained in the first step and stirred, or by a column method in which the extract obtained in the first step is passed through a column packed with activated carbon.

[0038] In the activated carbon treatment, the amount of activated carbon to be contacted with the extract obtained in the first step is, for example, about 10 to 100,000 mg, preferably about 10 to 10,000 mg, and more preferably about 10 to 2,000 mg, calculated as the dry weight of the extract obtained in the first step, per 1 g of activated carbon.

[0039] In the activated carbon treatment, the time for contacting the extract obtained in the first step with activated carbon is, for example, about 1 to 1440 minutes, preferably about 10 to 300 minutes, and more preferably about 30 to 180 minutes. The temperature condition during the activated carbon treatment is not particularly limited, and may be, for example, about 20 to 100°C, preferably about 20 to 90°C, and more preferably about 20 to 80°C.

[0040] Thus, by performing the activated carbon treatment and recovering the liquid fraction that has not been adsorbed by the activated carbon, a mulberry leaf extract with reduced unpleasant taste and odor can be obtained. The obtained mulberry leaf extract can be concentrated or dried as needed for use as a concentrated extract or a dried extract.

[0041] 2. Mulberry leaf extract The mulberry leaf extract obtained by the above manufacturing method has reduced unpleasant taste and odor, and one of its characteristics is that the content of n-hexanal is low. As a preferred embodiment of the mulberry leaf extract obtained by the above manufacturing method, the n-hexanal concentration measured under the following conditions is 0.75 ppb or less, preferably 0.70 ppb or less, more preferably 0.65 ppb or less. Also, the lower limit of the n-hexanal concentration is not particularly limited, and examples thereof include 0.00 ppb or more, 0.30 ppb or more, 0.40 ppb or more, or 0.45 ppb or more. <Measurement conditions for n-hexanal concentration> Dilute the mulberry leaf extract with water so that the amount of α-glucosidase inhibitor becomes 5000 IU / ml. Next, measure the n-hexanal concentration of the diluted solution by gas chromatography-mass spectrometry (GC / MS) using the absolute calibration curve method.

[0042] Here, 1 IU (Inhibition Unit) of α-glucosidase inhibitory activity is the amount of inhibitor that can inhibit α-glucosidase derived from rat small intestine by 50% under the following conditions. <Measurement conditions for α-glucosidase inhibitory activity> Add an appropriate amount of α-glucosidase crude enzyme solution derived from rat small intestine to an aqueous maltose solution with a final concentration of 100 mM, hold at 37°C for 40 minutes, and set the reaction conditions so that 115 - 125 mg / dL of glucose is generated. In 1 ml of this reaction system, the unit of inhibitory activity that can inhibit the activity of α-glucosidase derived from rat small intestine by 50% is defined as 1 IU. The α-glucosidase crude enzyme solution is prepared by suspending rat small intestine acetone powder in 0.1 M phosphate buffer (pH 7.0) at a concentration of 10% by mass, and using the centrifuged supernatant.

[0043] Furthermore, one embodiment of the mulberry leaf extract obtained by the above-described production method is characterized by reduced coloration compared to conventional mulberry leaf extracts. A preferred embodiment of the mulberry leaf extract obtained by the above-described production method exhibits an absorbance at a wavelength of 405 nm of 0.300 or less, preferably 0.200 or less, more preferably 0.100 or less, and even more preferably 0.075 or less, when diluted with water to an α-glucosidase inhibitory activity of 5000 IU / ml and filtered through a 0.45 μm membrane filter. The lower limit of the absorbance at a wavelength of 405 nm is not particularly limited, but examples include 0.000 or more, 0.010 or more, 0.020 or more, 0.030 or more, 0.040 or more, or 0.045 or more. The α-glucosidase inhibitory activity of 1 IU of mulberry leaf extract is as described above.

[0044] The mulberry leaf extract obtained by the above-mentioned production method can be used as an ingredient for foods and beverages, a compounding ingredient for pharmaceuticals, etc. In particular, the mulberry leaf extract obtained by the above-mentioned production method has reduced unpleasant taste and odor, making it easy to ingest, and therefore is particularly suitable as an ingredient for foods and beverages.

[0045] Foods and drinks containing the mulberry leaf extract obtained by the above-mentioned production method include general foods and drinks, as well as health functional foods such as foods for specified health uses, foods with nutrient functions, and foods with functional claims.

[0046] The types of food and drink to be blended with the mulberry leaf extract obtained by the above-mentioned production method are not particularly limited, and examples thereof include confectioneries such as cookies, biscuits, chocolate biscuits, crackers, pies, puddings, butter cream, custard cream, cream puffs, waffles, sponge cakes, donuts, chocolate, chewing gum, caramel, and candy; breads such as white bread, French bread, cooked bread, melon bread, bean paste bread, cream buns, jam bread, rolls, and croissants; beverages such as soft drinks, milk drinks, lactic acid bacteria drinks, almond drinks, carbonated drinks, fruit juice drinks, vegetable drinks, vegetable and fruit drinks, powdered drinks, jelly drinks, coffee drinks, black tea drinks, green tea drinks, barley tea, oolong tea, roasted green tea, jasmine tea, rooibos tea, mulberry tea, blended tea, sports drinks, milk, nutritional drinks, energy drinks, non-alcoholic drinks, and alcoholic drinks; desserts such as yogurt, pudding, jelly, pudding, and mousse; frozen desserts such as ice cream, soft serve ice cream, sorbet, and frozen desserts; instant soups and instant juices. Instant food and beverages such as sauce, instant coffee, instant sweet red bean soup, instant curry, instant Chinese rice bowl, instant beef bowl, and instant oyakodon; bases for rice dishes such as kamameshi and gomoku gohan; sauce bases for curry, hayashi, stew, meat sauce, and white sauce; processed livestock foods such as ham, sausage, bacon, shoulder bacon, liver paste, hamburger steak, and meatballs; processed fish foods such as kamaboko, fish ham, fish sausage, chikuwa, and tempura; noodles such as Chinese noodles, udon, and soba; soy sauce, powdered soy sauce, miso, powdered miso, and moromi mash These include condiments such as hishio, furikake, mayonnaise, dressing, vinegar, sanbai-zu, powdered sushi vinegar, Chinese seasonings, tempura sauce, noodle soup, sauces, ketchup, grilled meat sauce, dashi stock, compound seasonings, and mirin; cooked rice foods such as white rice, fried rice, pilaf, porridge, chestnut rice, red rice, mixed rice, and vinegared rice; soy processed foods such as tofu, deep-fried tofu, tofu, ganmodoki, yuba, natto, and soy milk; processed fruit or vegetable foods such as jam, marmalade, and syrup-preserved foods; and supplements such as tablets, granules, powders, capsules, and soft capsules.

[0047] When the mulberry leaf extract obtained by the above-mentioned production method is incorporated into a food, drink, or pharmaceutical product, the amount of the mulberry leaf extract to be incorporated may be appropriately determined depending on the type of food, drink, or pharmaceutical product, but for example, the amount of the mulberry leaf extract converted into α-glucosidase inhibitory activity per 100 g of food, drink, or pharmaceutical product may be about 25 to 2,500,000 IU, preferably about 250 to 250,000 IU. Here, the "converted amount of α-glucosidase inhibitory activity" refers to the value converted into the α-glucosidase inhibitory activity of the mulberry leaf extract. [Example]

[0048] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0049] Test Example 1: Production and evaluation of mulberry leaf extract 1. Manufacturing of mulberry leaf extract 1-1. Pretreatment of mulberry leaves (1) Vapor heat treatment Mulberry leaves were promptly refrigerated after harvesting and then subjected to moist heat treatment within 24 hours of harvesting under the conditions shown in Table 1. The steam treatment was carried out using a convection oven (SelfCooking Center, manufactured by RATIONAL) in a steam (100% humidity) atmosphere. After the steam treatment, the mulberry leaves were dried at 42°C for 16 hours and then crushed. [Table 1]

[0050] (2) Freeze-drying process Mulberry leaves were immediately refrigerated after harvesting and then freeze-dried at -80°C for 48 hours within 24 hours of harvesting. The freeze-dried mulberry leaves were then crushed.

[0051] (3) Drying process Mulberry leaves were immediately refrigerated after harvesting and then dried at 35°C for 48 hours within 24 hours of harvesting. After drying, the mulberry leaves were crushed.

[0052] (4) Untreated Mulberry leaves were immediately refrigerated after harvesting and used as they were within 24 hours of harvesting without any pretreatment.

[0053] 1-2. Extraction process 20 g (dry weight equivalent) of mulberry leaves pretreated under the above conditions or untreated mulberry leaves was added to 80 ml of water or aqueous ethanol (ethanol concentration: 10 mass%, 20 mass%, 30 mass%, or 40 mass%) and extracted for 60 minutes under boiling conditions. After extraction, the extract was filtered using a 0.45 μm membrane filter (manufactured by Merck Millipore) to obtain an extract.

[0054] 1-3. Activated carbon treatment To 45 ml of the extract obtained after the extraction process (approximately 4,000 mg in dry weight), 4 g of powdered chemically activated wood carbon (Seijin Shirasagi, manufactured by Osaka Gas Chemicals Co., Ltd.) was added, and the mixture was shaken for 60 minutes in a shaker, after which it was filtered using a 0.45 μm membrane filter (manufactured by Merck Millipore) to obtain a mulberry leaf extract.

[0055] 2.Analysis / measurement method 2-1. Absorbance of extract (before activated carbon treatment) The extract obtained after the extraction treatment (i.e., the extract before activated carbon treatment) was diluted with water to a Brix of 0.035 to obtain a diluted solution. The absorbance of the diluted solution at wavelengths of 300 nm and 320 nm was measured using an absorption spectrophotometer (Infinite200Pro M Plex, manufactured by Tecan). The absorbance at wavelengths of 300 nm, A 300 and absorbance A at a wavelength of 320 nm 320 Round off the measured values ​​to the third decimal place, calculate the significant figures to the second decimal place, and calculate the ratio (A 320 / A 300 ) was calculated.

[0056] 2-2. n-Hexanal concentration in mulberry leaf extract (after activated carbon treatment) The mulberry leaf extract obtained after activated carbon treatment was diluted with water so that the α-glucosidase inhibitory activity became 5000 IU / ml to obtain a diluted solution. Next, the n-hexanal concentration of the diluted solution was measured by headspace solid-phase microextraction / gas chromatography-mass spectrometry (HS-SPME / GC / MS) using the absolute calibration curve method. The analysis conditions for HS-SPME / GC / MS are as follows. <HS-SPME / GC / MS Analysis Conditions> ·sampling : 1 ml was measured and sealed with a magnetic cap in a 20 ml brown headspace vial. SPME conditions Fiber: 50 / 30μm DVB / CAR / PDMS (1 cm) Preincubation: 40°C, 10 minutes Extraction: 40°C, 15 minutes Desorption: 240°C, 1 minute ·Instrumental analysis conditions Apparatus: GCMS-QP2010 (manufactured by Shimadzu Corporation) Inlet temperature: 240°C Split ratio: Splitless Sampling time: 1 minute Column: DB-WAX (length 60 m, inner diameter 0.25 mm, film thickness 0.25 μm) Temperature rising condition: 40°C (5 minutes) → 4°C / min → 230°C (10 minutes) → 5°C / min → 250°C (0 minutes) Carrier gas: He Pressure: 138.5 kPa (pressure control) Flow rate · Flow amount: 1.26 ml / min Ion source temperature: 200°C Detector: MS Analysis mode: SIM

[0057] 2-3. Measurement of α-glucosidase inhibitory activity An appropriate amount of crude α-glucosidase solution derived from rat small intestine was added to a 100 mM maltose solution, and the mixture was incubated at 37°C for 40 minutes. The reaction conditions were set to produce 115-125 mg / dL of glucose. The α-glucosidase inhibitory activity of each mulberry leaf extract was measured, with 1 IU being the unit of inhibitory activity required to inhibit 50% of the activity of rat small intestine α-glucosidase in 1 ml of this reaction mixture. The α-glucosidase crude enzyme solution was prepared by suspending rat small intestine acetone powder (Sigma) in 0.1 M phosphate buffer (pH 7.0) at a concentration of 10% by mass, followed by centrifugation of the supernatant.

[0058] 2-4. Evaluation of the taste and odor of mulberry leaf extract (after activated carbon treatment) The mulberry leaf extract obtained after activated carbon treatment was diluted with water to obtain a diluted solution with an α-glucosidase inhibitory activity of 5000 IU / ml. Five expert sensory panelists tasted the diluted solution and conducted a sensory evaluation. The sensory evaluation was conducted by the five expert sensory panelists, who then decided whether the extract met any of the following criteria: AA: No unpleasant taste (bitterness, astringency) or unpleasant odor (grassy, ​​fishy odor) is detected. A: There is almost no unpleasant taste (bitterness, astringency) or unpleasant odor (grassy, ​​fishy odor). B: There is a slight unpleasant taste (bitterness / astringency) and unpleasant odor (grassy / fishy odor). C: Unpleasant taste (bitterness, astringency) and unpleasant odor (grassy, ​​fishy odor) are perceived. D: Strong unpleasant taste (bitterness, astringency) and unpleasant odor (grassy, ​​fishy odor).

[0059] 2-5. Evaluation of coloration of mulberry leaf extract (after activated carbon treatment) The mulberry leaf extract obtained after activated carbon treatment was diluted with water to obtain a diluted solution with an α-glucosidase inhibitory activity of 5000 IU / ml. The diluted solution was filtered using a 0.45 μm membrane filter (Merck Millipore), and the absorbance at a wavelength of 405 nm was measured using an absorption spectrophotometer (Infinite200Pro M Plex, Tecan). The absorbance at a wavelength of 405 nm was rounded to the fourth decimal place and expressed as a significant value to the third decimal place.

[0060] Furthermore, five expert sensory panelists observed the appearance of the diluted solution and evaluated the degree of coloration. The sensory evaluation was conducted by the five expert sensory panelists in consultation with each other, and they judged whether the diluted solution met any of the following criteria. +: Coloration is confirmed by visual inspection. -: No coloring can be visually confirmed.

[0061] 3.Results The results obtained are shown in Tables 2 and 3.

[0062] The mulberry leaf extract obtained by subjecting mulberry leaves to extraction and activated carbon treatment without pretreatment had an unpleasant taste and odor (Comparative Example 1-1). Furthermore, even when the mulberry leaves were subjected to pretreatment by freeze-drying or drying at 35°C and then subjected to extraction and activated carbon treatment, the mulberry leaf extract still had an unpleasant taste and odor (Comparative Examples 1-2 and 1-3). Furthermore, even when the mulberry leaf extract was obtained by subjecting mulberry leaves to pretreatment by steaming and then subjected to extraction and activated carbon treatment, the integrated value after steaming was 60 ~ 90 When the temperature was less than 1000°C·sec, the unpleasant taste and odor of the mulberry leaf extract were felt (Comparative Examples 1-4 to 1-11). Under the conditions of Comparative Examples 1-1 to 1-11, the ratio of the extract before the activated carbon treatment (A 320 / A 300 ) was 0.98 or higher.

[0063] In addition, as a preprocessing step, the integral value 60 ~ 90 By performing steaming treatment at 1000°C·sec or more, the ratio of extractables before activated carbon treatment (A 320 / A 300 ) was 0.97 or less, when aqueous ethanol with an ethanol concentration of 40% by mass was used as the extraction solvent, an unpleasant taste and odor were felt (Comparative Example 1-12).

[0064] In contrast, the integral value is used as preprocessing. 60 ~ 90When steaming treatment was performed at a temperature of 1000°C·sec or higher, followed by extraction treatment using water or aqueous ethanol with an ethanol concentration of 30% by mass or less and treatment with activated carbon, mulberry leaf extracts with sufficiently reduced unpleasant taste and odor were obtained (Examples 1-1 to 1-9). Under the conditions of Examples 1-1 to 1-9, the ratio of the extract before the activated carbon treatment (A 320 / A 300 ) was 0.97 or less. Furthermore, as can be seen from Examples 1-10 to 1-17, even when the maximum temperature reached in the steaming treatment exceeded 90°C, the integral value 60 ~ 90 If the temperature is 1000°C·sec or higher, the ratio of extractables before activated carbon treatment (A 320 / A 300 ) was 0.97 or less, and a mulberry leaf extract with sufficiently reduced unpleasant taste and odor was obtained.

[0065] Furthermore, the mulberry leaf extracts obtained in Examples 1-1 to 1-9 had an n-hexanal concentration of 0.75 ppb or less in a diluted solution diluted with water to an α-glucosidase inhibitory activity of 5000 IU / ml, and the absorbance of the diluted solution at 405 nm was less than 0.300, and coloration was also suppressed.

[0066] From the above results, it was found that the ratio (A 320 / A 300 It was found that by obtaining an extract with an integral value of 0.97 or less and treating the extract with activated carbon, it is possible to obtain a mulberry leaf extract with reduced unpleasant taste and odor. 60 ~ 90 By steaming the mulberry leaves at a temperature of 1000°C·sec or more, the ratio (A 320 / A 300 It was also revealed that an extract (before activated carbon treatment) with a β-glucan value of 0.97 or less could be obtained.

[0067] [Table 2]

[0068] [Table 3]

[0069] Test Example 2: Production and evaluation of food and drink containing mulberry leaf extract 1. Evaluation Method Various foods and beverages were produced using the mulberry leaf extracts obtained in Examples 1-14 or Comparative Examples 1-4, and the taste, smell, and appearance of the various foods and beverages were evaluated.

[0070] The taste and smell were evaluated by having five expert sensory panelists taste each food and drink and then deciding whether it met any of the following criteria in a consensus among the five expert sensory panelists. AA: The unpleasant taste (bitterness, astringency) and unpleasant odor (grassy, ​​fishy odor) caused by mulberry leaf extract are completely absent. A: The unpleasant taste (bitterness, astringency) and unpleasant odor (grassy, ​​fishy odor) caused by mulberry leaf extract are hardly noticeable. B: There is a slight unpleasant taste (bitterness, astringency) and unpleasant odor (grassy, ​​fishy odor) caused by mulberry leaf extract. C: The unpleasant taste (bitterness, astringency) and unpleasant odor (grassy, ​​fishy odor) caused by mulberry leaf extract are noticeable. D: The unpleasant taste (bitterness, astringency) and unpleasant odor (grassy, ​​fishy odor) caused by mulberry leaf extract are strongly felt.

[0071] Furthermore, the appearance of each food and drink was evaluated by five expert sensory panelists who observed its appearance and decided, through consensus among the five expert sensory panelists, whether it met any of the following criteria. +: Coloring caused by mulberry leaf extract is visually confirmed. -: No coloring caused by mulberry leaf extract can be visually confirmed.

[0072] 2. Production and evaluation of food and beverages Cookies The dough was prepared by mixing the ingredients shown in Table 4. The dough was then molded into a thickness of approximately 5 mm and baked at 170°C for approximately 15 minutes to obtain cookies. The taste, smell, and appearance of the resulting cookies were evaluated, and the results are shown in Table 4.

[0073] [Table 4]

[0074] 2-2. Bread Bread was obtained by preparing dough with the composition shown in Table 5, fermenting, and baking. Specifically, strong flour, sugar, skim milk, dry yeast, and salt were mixed, followed by adding water and mulberry leaf extract and mixing. The dough was then kneaded and combined. Next, unsalted butter was added and kneaded. The dough was then placed in a bowl, wrapped in plastic wrap, and kept at 40°C for fermentation until the volume approximately doubled. The dough was then divided into 2-3 equal parts, covered with a wet cloth, and left at room temperature for 15 minutes to degas. The dough was then re-formed into balls, covered with plastic wrap and a wet cloth, and kept at 40°C for 30 minutes for fermentation. Once the volume of the dough had approximately doubled, the wet cloth and plastic wrap were removed, and the dough was baked at 190°C for approximately 15 minutes to obtain bread. The results of evaluation of the taste, odor, and appearance of the resulting bread are shown in Table 5.

[0075] [Table 5]

[0076] 2-3. Beverages A beverage was obtained by mixing the ingredients shown in Table 6. The results of evaluation of the taste, odor, and appearance of the obtained beverage are shown in Table 6.

[0077] [Table 6]

[0078] 2-4. Yogurt Yogurt was obtained by mixing the ingredients shown in Table 7. The results of evaluation of the taste, odor, and appearance of the obtained yogurt are shown in Table 7.

[0079] [Table 7]

[0080] 2-5. Chocolate Chocolates were prepared according to the composition shown in Table 8. Specifically, the chocolate was melted in a water bath at about 50°C, and then the mulberry leaf extract was added and mixed well. The mixture was then molded and allowed to stand at room temperature to solidify, yielding chocolate. The results of evaluation of the taste, odor, and appearance of the resulting chocolate are shown in Table 8.

[0081] [Table 8]

[0082] 2-6.Candy All the ingredients shown in Table 9 were placed in a pot and melted, then boiled over medium heat for about 10 minutes, poured into a mold, and allowed to solidify to obtain candy. The results of evaluation of the taste, odor, and appearance of the resulting candy are shown in Table 9.

[0083] [Table 9]

[0084] 2-7. Pudding Pudding was obtained using the ingredients shown in Table 10. Specifically, eggs were thoroughly beaten, and milk, sugar, and mulberry leaf extract were added and mixed. The mixed ingredients were then strained through a tea strainer and poured into a mold. The mold was covered with aluminum foil, placed in a steamer, and heated over low heat for approximately 15 minutes to obtain a pudding. The results of evaluation of the taste, odor, and appearance of the obtained pudding are shown in Table 10.

[0085] [Table 10]

[0086] 2-8. Ice Cream Ice cream was prepared using the ingredients shown in Table 11. Specifically, egg yolk and sugar were first placed in a bowl and mixed thoroughly. Fresh cream, milk, and mulberry leaf extract were placed in a separate pot and heated. When the pot began to bubble, the pot was removed from the heat and the mixture was gradually added to the bowl containing the egg yolk and sugar while mixing. The resulting mixture was placed in a metal container, allowed to cool, then covered and cooled to -20°C. The mixture was stirred after 2-3 hours, and then stirred 3-4 times every 30 minutes to prepare ice cream. The results of evaluation of the taste, odor, and appearance of the resulting ice cream are shown in Table 11.

[0087] [Table 11]

[0088] 2-9. Sherbet Ice cream was obtained using the ingredients shown in Table 12. Specifically, orange juice and sugar were first placed in a pot and heated to dissolve the sugar. Next, the pot was removed from the heat, and the mulberry leaf extract was added to the remaining orange juice and mixed. The resulting mixture was poured into a metal tray, covered, and cooled to -20°C. After one hour, the mixture was stirred, and then cooled at -20°C for at least two hours to solidify, yielding a sorbet. The results of evaluation of the taste, odor, and appearance of the resulting sorbet are shown in Table 12.

[0089] [Table 12]

[0090] 2-10. Soup Soup was obtained by mixing the ingredients shown in Table 13. The results of evaluation of the taste, smell, and appearance of the obtained soup are shown in Table 13.

[0091] [Table 13]

[0092] 2-11. Instant curry A retort curry was prepared using the ingredients shown in Table 14. Specifically, the retort curry was heated in a hot water bath, and then mulberry leaf extract was added and mixed well to obtain the retort curry. The evaluation results for the taste, odor, and appearance of the obtained retort curry are shown in Table 14.

[0093] [Table 14]

[0094] 2-12. Ham Ham was obtained using the ingredients shown in Table 15. Specifically, pork was rubbed with salt, sugar, and mulberry leaf extract, placed in a sealed plastic bag, and then heated in hot water at 60-70°C for about 2 hours. The results of evaluation of the taste, odor, and appearance of the obtained ham are shown in Table 15.

[0095] [Table 15]

[0096] 2-13.Kamaboko Kamaboko was obtained using the ingredients shown in Table 16. Specifically, fish paste, salt, and mulberry leaf extract were mixed in a food processor, placed on a wooden board, shaped, and heated in a steamer for about 10 minutes to obtain kamaboko. The results of evaluation of the taste, odor, and appearance of the obtained kamaboko are shown in Table 16.

[0097] [Table 16]

[0098] 2-14. Cooked rice Cooked rice was obtained using the ingredients shown in Table 17. Specifically, rice, water, and mulberry leaf extract were placed in a rice cooker and cooked to obtain cooked rice. The results of evaluation of the taste, odor, and appearance of the obtained cooked rice are shown in Table 17.

[0099] [Table 17]

[0100] 2-15. Noodles Noodles were obtained using the ingredients shown in Table 18. Specifically, salt, water, and mulberry leaf extract were first mixed well in a bowl, and then all-purpose flour was added and mixed well again, all together to form dough. The dough was then left to rest at room temperature for 1-2 hours, after which it was rolled out to a thickness of approximately 3 mm with a rolling pin and cut into 5 mm widths. The noodles were then boiled for approximately 10-15 minutes, washed under running water, and drained to obtain noodles. The results of evaluation of the taste, odor, and appearance of the obtained noodles are shown in Table 18.

[0101] [Table 18]

[0102] 2-16. Sushi rice Vinegared rice was prepared using the ingredients shown in Table 19. Specifically, vinegar, sugar, salt, and mulberry leaf extract were first mixed thoroughly to prepare a mixture of vinegar. The mixture of vinegar was then mixed evenly with cooked rice to obtain vinegared rice. The results of evaluation of the taste, odor, and appearance of the obtained vinegared rice are shown in Table 19.

[0103] [Table 19]

Claims

1. A method for producing a mulberry leaf extract, comprising: Mulberry leaves are extracted with water containing 0 to 30% by mass of lower alcohol, and the absorbance A 300 Absorbance A at a wavelength of 320 nm 320 The ratio (A 320 / A 300 a first step of obtaining an extract having a value of 0.97 or less; a second step of subjecting the extract obtained in the first step to an activated carbon treatment; A manufacturing method comprising:

2. The mulberry leaves to be subjected to the extraction treatment in the first step are pretreated, 2. The manufacturing method according to claim 1, wherein the pretreatment is a steam treatment carried out at a temperature condition of 60°C or higher, and is carried out so that an integrated value of the heating temperature (°C) and the heating time (seconds) in a temperature range of 60 to 90°C is 1000°C-seconds or more during the entire treatment time if the maximum temperature reached does not exceed 90°C, or during the treatment time until 90°C is reached if the maximum temperature reached exceeds 90°C.

3. The method according to claim 1 or 2, wherein the lower alcohol is ethanol.

4. A mulberry leaf extract obtained by the manufacturing method according to any one of claims 1 to 3.

5. A mulberry leaf extract having an n-hexanal concentration of 0.75 ppb or less as measured under the following measurement conditions. <Conditions for measuring n-hexanal concentration> The mulberry leaf extract is diluted with water to an α-glucosidase inhibitory activity of 5000 IU / ml, and the n-hexanal concentration of the diluted solution is then measured by gas chromatography mass spectrometry using the absolute calibration curve method. The α-glucosidase inhibitory activity unit (IU) is the amount of inhibitor determined by the following method. First, an appropriate amount of rat small intestine-derived α-glucosidase crude enzyme solution is added to a maltose solution with a final concentration of 100 mM, and the mixture is kept at 37°C for 40 minutes. The reaction conditions are set so that 115-125 mg / dL of glucose is produced. 1 IU is the inhibitory activity unit that can inhibit 50% of the activity of rat small intestine-derived α-glucosidase in 1 ml of this reaction system. The α-glucosidase crude enzyme solution is prepared by suspending rat small intestine acetone powder in 0.1 M phosphate buffer (pH 7.0) to a concentration of 10% by mass, and then centrifuging the resulting supernatant.

6. 6. The mulberry leaf extract according to claim 5, wherein when diluted with water to an α-glucosidase inhibitory activity of 5000 IU / ml and filtered through a 0.45 μm membrane filter, the diluted solution has an absorbance of 0.300 or less at a wavelength of 405 nm.

7. A food or drink comprising the mulberry leaf extract according to any one of claims 4 to 6.

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