Method for reducing unpleasant odor component in roasted coffee beans

Abstract

The present invention provides a feature which suppresses the formation of indoles and scatoles, which are known to be an unpleasant odor component in roasted coffee beans, without heat-treating raw coffee beans to a high temperature of 100°C or higher. More specifically, the present invention moistens raw coffee beans with water and subjects the same to a heat treatment at a temperature less than 100°C at atmospheric pressure, causes the heat-treated raw coffee beans to absorb an organic acid / and or a saccharide, and thereafter, roasts the coffee beans.

Description

Method for reducing unpleasant odor components in roasted coffee beans

[0001] The present invention relates to a method for reducing unpleasant odor components in roasted coffee beans. More specifically, the present invention provides a method for reducing unpleasant odor components generated in the subsequent roasting process by adding water, heat, and an organic acid and / or sugar to green coffee beans.

[0002] Coffee is a popular beverage enjoyed worldwide, and coffee with a balanced aroma, sweetness, bitterness, and acidity is preferred. Coffee is a delicate beverage, as even slight variations in the conditions of the selection, roasting, and brewing of green coffee beans can significantly affect the hundreds of compounds that determine its flavor, aroma, and richness. There are three original species of coffee: Arabica, Robusta, and Liberica. Arabica is grown in its native countries of Ethiopia, Brazil, Colombia, and other Central and South American countries, as well as Hawaii and India. It accounts for over 70% of the world's coffee production and is known for its excellent aroma and acidity, making it a high-quality coffee. Robusta is grown in its native African countries, including the Congo, Indonesia, and Trinidad and Tobago. It accounts for approximately 30% of the world's coffee production and is highly productive, being used in instant coffee and canned coffee. Robusta coffee beans have an earthy, moldy flavor and are considered inferior in quality to Arabica. The Liberica variety is native to the west coast of Africa and is grown in countries such as the Republic of Liberia, Côte d'Ivoire, Angola, Indonesia, and Liberia. It accounts for only a small percentage of the world's coffee production and is consumed almost exclusively in the regions where it is grown.

[0003] One known method for removing the earthy and moldy flavor of Robusta coffee beans and effectively improving their quality is to steam-treat moistened Robusta coffee beans at 260-300°F (approximately 126-149°C) under pressure exceeding atmospheric pressure, and then roast the treated beans to improve the quality of the roasted Robusta coffee beans (Patent Document 1). This document suggests that the earthy and moldy flavor is likely caused by 2-methylisoborneol. Other methods for improving coffee bean quality include adding sugars and amino acids to the green coffee beans and then heat-treating them under pressures exceeding atmospheric pressure (e.g., Patent Documents 2 and 3). Patent Document 4 discloses a method for increasing the β-damascenone content in green coffee beans by a high-temperature, high-pressure treatment process in which acid-treated green coffee beans, which have been absorbed into an acidic solution, are treated with a steam-containing gas at a temperature of 100-200°C and a pressure (gauge pressure) exceeding 0 MPa. This method makes it possible to produce green coffee beans and roasted coffee beans with an enhanced sweet aroma and improved flavor. Both of these methods require equipment capable of high-temperature heating under pressure.

[0004] It was subsequently confirmed that, regardless of the coffee bean variety, green coffee beans obtained from immature berries contain a large amount of tryptophan, the content of which decreases as the berries ripen, and that indole and skatole, which are produced as thermal decomposition products of tryptophan during roasting, are components that cause unpleasant odors in coffee (Patent Document 5).Patent Document 5 provides a method for obtaining roasted coffee beans with low indole and skatole contents by using a near-infrared method to select green coffee beans with low tryptophan contents and use them as a raw material.

[0005] Meanwhile, Patent Document 6 discloses a method for reducing aroma components in roasted coffee beans, such as indole and skatole, which are believed to cause unpleasant odors, by soaking green coffee beans in sake lees and then roasting them. In this method, contact between the green coffee beans and the sake lees is preferably carried out in a temperature environment of 0 to 30°C to prevent denaturation of the sake lees, which contain various components, and the alcohol content of the soaking liquid in which the green coffee beans are soaked is preferably 0.5 to 4% by mass. It has also been shown that the longer the soaking time in sake lees, the greater the effect of reducing unpleasant odors, and a soaking time of 16 hours or more is particularly preferred.

[0006] Japanese Patent Application Laid-Open No. 6-303905 Japanese Patent Application Laid-Open No. 2000-342182 Japanese Patent Application Laid-Open No. 2010-166868 Japanese Patent Application Laid-Open No. 2018-057369 Japanese Patent Application Laid-Open No. 2016-167993 Japanese Patent Application Laid-Open No. 2022-015956

[0007] Toshiki Minetoki, Journal of the Association of Brewing, Vol. 109, No. 1, pp. 11-20 (2014); Hiromitsu Nagata et al., Research Report of the Institute of Oriental Food Industry, Toyo Food Industry College, 20, 27-34 (1994); Mutsuko Takaya et al., Bulletin of Shokei Gakuin University, No. 60, pp. 19-29, accepted September 15, 2010

[0008] The present invention provides a technology for suppressing the formation of indole and skatole, which are known to cause unpleasant odors in roasted coffee beans, without heat-treating green coffee beans at high temperatures of 100°C or higher.

[0009] In summary, the present invention involves adding water to green coffee beans, then heating them at a temperature of less than 100°C under atmospheric pressure to impregnate the green coffee beans with water, allowing the impregnated green coffee beans to absorb organic acids and sugars, and then roasting the beans, thereby suppressing the formation of indole and skatole in the roasted coffee beans. As a result, the indole and skatole contents in the roasted coffee beans are reduced compared to the indole and skatole contents in roasted coffee beans obtained by roasting unprocessed green coffee beans.

[0010] More specifically, the present invention provides the following technologies. [1] A method for producing roasted coffee beans, comprising: (1) a step of adding 10% or more by mass of water to green coffee beans; (2) after the water adding step, a step of heating the green coffee beans and water to a temperature of less than 100°C under atmospheric pressure to impregnate the green coffee beans with water; (3) after the water impregnation step, a step of allowing the water-impregnated green coffee beans to absorb an organic acid and / or sugars; and (4) after the organic acid and / or sugar absorption step, a step of roasting the green coffee beans that have absorbed the organic acid and / or sugars. [2] The production method according to Item 1, wherein, in the organic acid and / or sugar absorption step, the water-impregnated green coffee beans are impregnated with an aqueous solution containing an organic acid and / or sugars. [3] The manufacturing method according to Item 1 or 2, wherein the organic acid is at least one selected from the group consisting of lactic acid, citric acid, and acetic acid, and the sugar is at least one selected from the group consisting of glucose, fructose, and maltose. [4] The manufacturing method according to any one of Items 1 to 3, wherein 0.5% by mass or more of an organic acid or sugar is absorbed by the green coffee beans. [5] The manufacturing method according to any one of Items 1 to 4, wherein the green coffee beans are Robusta. [6] Roasted coffee beans manufactured by the manufacturing method according to any one of Items 1 to 5. [7] A food or drink containing the roasted coffee beans or an extract thereof according to Item 6. [8] A method for reducing indole and skatole in roasted coffee beans, comprising: (1) a step of adding 10% or more by mass of water to green coffee beans; (2) after the water adding step, a step of heating the green coffee beans and water to a temperature of less than 100°C under atmospheric pressure to impregnate the green coffee beans with water; (3) after the water impregnation step, a step of allowing the green coffee beans impregnated with water to absorb an organic acid and / or sugars; and (4) after the organic acid and / or sugar absorption step, a step of roasting the green coffee beans that have absorbed the organic acid and / or sugars.

[0011] The roasted coffee beans produced by the production method of the present invention can be extracted under normal conditions. The roasting conditions are not particularly limited as long as they are normal conditions, and for example, the roasting conditions described in Non-Patent Document 3 can be referenced.

[0012] The roasted coffee beans or their extract thus obtained can be added to a variety of foods and beverages, such as coffee, coffee drinks, coffee-containing soft drinks, coffee-containing carbonated drinks, instant coffee, coffee concentrates, milk drinks, dairy products, cream, confectionery, and fresh confectionery.

[0013] In conventional technology, it was necessary to heat-treat green coffee beans at high temperatures of 100°C or higher. However, according to the present invention, it is possible to suppress the formation of specific unpleasant odor components (indole and skatole) that occur in roasted coffee beans in a short period of time under heating conditions of less than 100°C.

[0014] Graph comparing the effect of adding organic acids to green Robusta coffee beans (produced in Vietnam) on the indole (top row) and skatole (bottom row) content of each sample. Graph comparing the effect of the amount of water added to green Robusta coffee beans (produced in Vietnam) on the indole (top row) and skatole (bottom row) content of each sample. Graph comparing the effect of the amount of organic acid added to green Robusta coffee beans (produced in Vietnam) on the indole (top row) and skatole (bottom row) content of each sample. Graph comparing the effect of adding sugars to green Robusta coffee beans (produced in Vietnam) on the indole (top row) and skatole (bottom row) content of each sample. Graph comparing the effect of the amount of water added to green Robusta coffee beans (produced in Vietnam) on the indole (top row) and skatole (bottom row) content of each sample. Graph comparing the effect of the amount of sugar added to Robusta coffee beans (produced in Vietnam) on the indole (top row) and skatole (bottom row) content of each sample. Graph comparing the effect of adding organic acids and sugars to Robusta coffee beans (produced in Vietnam) on the indole (top row) and skatole (bottom row) content of each sample. Graph comparing the effect of the amount of water added to Robusta coffee beans (produced in Vietnam) on the indole (top row) and skatole (bottom row) content of each sample. Graph comparing the effect of adding organic acids and sugars to Robusta coffee beans (produced in Uganda) and Robusta coffee beans (produced in Indonesia) on the indole (top row) and skatole (bottom row) content of each sample. Graph comparing the effect of adding organic acids and sugars to Arabica coffee beans (produced in Brazil) on the indole (top row) and skatole (bottom row) content of each sample. This graph compares the effect of drying Robusta coffee beans (produced in Vietnam) after absorbing organic acids and sugars on the indole (top row) and skatole (bottom row) content of each sample.

[0015] 1. Green Coffee Beans Targeted by the Present Invention The type of green coffee beans targeted by the present invention is not limited, and may be Arabica, Robusta, or Liberica, and there are no particular restrictions on the place of origin. Examples of green coffee beans include Arabica, which is grown in Central and South America (e.g., Ethiopia, Brazil, and Colombia), Hawaii, and India; Robusta, which is grown in various parts of Africa (e.g., Congo), Indonesia, and Trinidad and Tobago); and Liberica, which is grown in the Republic of Liberia on the west coast of Africa, Côte d'Ivoire, Angola, Indonesia, and Liberia. Brands of green coffee beans include Kilimanjaro, Blue Mountain, Emerald Mountain, Mocha, Brazil, Guatemala, Colombia, Hawaii-Kona, Mandheling, and Costa Rica. The moisture content of the green coffee beans is not particularly limited, but is, for example, 9 to 13% by mass, and typically 10 to 12% by mass. Since the present invention aims to reduce indole and skatole, which deteriorate the quality of roasted coffee beans, it is useful to apply the present invention to Robusta, a low-grade coffee that contains a high amount of tryptophan, a precursor of these components, as this will effectively demonstrate the effects of the present invention, but it may also be applied to green coffee beans classified as commercial coffee or higher. Furthermore, the green coffee beans to which the present invention is applied may be in the form of whole beans or ground.

[0016] 2. Method for Producing Roasted Coffee Beans According to the Present Invention The method for producing roasted coffee beans according to the present invention is characterized by comprising: (1) a step of adding 10% or more by mass of water to green coffee beans; (2) after the water adding step, a step of heating the green coffee beans and water to a temperature of less than 100°C under atmospheric pressure to impregnate the green coffee beans with water; (3) after the water impregnation step, a step of allowing the water-impregnated green coffee beans to absorb organic acids and / or sugars; and (4) after the organic acid and / or sugar absorption step, a step of roasting the green coffee beans that have absorbed the organic acids and / or sugars.

[0017] By undergoing the above steps, the indole and skatole contents in roasted coffee beans are reduced compared to the indole and skatole contents in roasted coffee beans obtained by roasting unprocessed green coffee beans. In this specification, "unprocessed green coffee beans" refer to beans in a state prior to undergoing the above step (1). Also, in this specification, "processed green coffee beans" refer to beans in a state following the above steps (1) to (3). It is believed that indole and skatole are produced by the thermal decomposition of tryptophan contained in green coffee beans. Therefore, in the present invention, it is presumed that by allowing organic acids or sugars to be absorbed into unroasted green coffee beans, the thermal decomposition of tryptophan alone is suppressed or the reaction between tryptophan and other components contained in the green coffee beans is promoted, thereby suppressing the formation of indole and skatole. Furthermore, in the present invention, the green coffee beans are impregnated with moisture through steps (1) and (2) above, and then step (3) is carried out in which organic acids and sugars are absorbed into the green coffee beans, so it is presumed that the organic acids and sugars easily penetrate into the green coffee beans, and the aforementioned suppression of indole and skatole formation is achieved throughout the green coffee beans. Therefore, compared to cases in which organic acids and sugars are absorbed into green coffee beans without going through either or both of steps (1) and (2) above, the present invention is superior in suppressing the formation of indole and skatole.

[0018] (1) Step of Adding Moisture to Green Coffee Beans In the present invention, "adding 10% by mass or more of moisture to the green coffee beans" means causing the green coffee beans and a predetermined amount of moisture to coexist in a container.

[0019] More specifically, the target green coffee beans and a predetermined amount of water are placed into a container. The container can be either a batch or continuous type, as long as it can heat and mix the green coffee beans with water. Examples of such a container include a pot, kettle, or cauldron; a cooking device equipped with a heating means and / or stirring means in the pot or kettle; a wet mixing device equipped with stirring blades; a food preparation or pharmaceutical manufacturing mixer equipped with a mixing plate inside the container and capable of rotating; a drum mixer designed to flow and mix the ingredients along the blades inside the mixing tank to gently mix the ingredients without destroying them; and a solid culture device with an internal, ventilated culture bed. These devices may also be equipped with a pressurizing means or a spraying means. The container can also be covered with a lid to prevent moisture from escaping. In the present invention, the lid may be a drop lid made of a heat-resistant film such as aluminum foil, or a snap-on type that closes the opening of the container. Furthermore, large devices such as those described above can be made airtight. In the present invention, heating to 100°C or higher under pressure is not intended, but in that case, it is preferable to use a heat-resistant container, and an autoclave can also be used as the heat-resistant container.

[0020] In the present invention, regardless of the type of green coffee beans or the moisture content of the green coffee beans at the time of adding moisture, a lower limit of 10% by mass or more, preferably 20% by mass or more, and more preferably 30% by mass or more of moisture is added per unit mass of the green coffee beans. The upper limit of the amount of moisture added per unit mass of the green coffee beans is not limited, but is 100% by mass or less, preferably 75% by mass or less, and more preferably 60% by mass or less. Adding 10% by mass or more of moisture and performing other treatments under the conditions specified in the present invention significantly reduces the indole and skatole content in the roasted coffee beans compared to roasted coffee beans produced without performing all of the treatments under the conditions specified in the present invention. Adding 75% by mass or less of moisture allows the green coffee beans to absorb substantially all of the moisture. In the present invention, the amount of water added relative to the mass of the target green coffee beans is, for example, 10% by mass or more, 10 to 100% by mass, 10 to 75% by mass, 20 to 65% by mass, 20 to 60% by mass, or 30 to 60% by mass. The water added may be pure water, ultrapure water, ion-exchanged water, filtered water, well water, natural water, mineral water, tap water, or a mixture thereof. The temperature of the water added is not particularly limited, except that the lower limit is higher than the freezing point of water and the upper limit is less than 100°C, which is the boiling point of water, under atmospheric pressure. It may be cold water below room temperature, water around room temperature, or warm or hot water above room temperature. In the present invention, the temperature of the water added is, for example, 0°C or higher but less than 100°C, 0 to 99°C, 5 to 99°C, or 5 to 95°C. Among these, work can be performed at room temperature or ordinary temperature in the work environment, or in a cold place, as long as the temperature range is 1 to 35°C, 1 to 30°C, 1 to 15°C, 5 to 35°C, 5 to 30°C, 15 to 35°C, 15 to 30°C, or 15 to 25°C. In the present invention, "room temperature" means 1 to 35°C, "ordinary temperature" means 15 to 35°C, and "cold place" means "1 to 15°C." In this specification, the symbol "to" connecting an upper limit and a lower limit includes both the upper limit and the lower limit. For example, "A to B" means greater than or equal to A and less than or equal to B.

[0021] The water to be added may be a liquid preparation obtained by mixing the above-mentioned water with spices (e.g., cocoa, cinnamon, vanilla, coriander, cardamom, cloves, ginger, nutmeg, allspice, garlic, and Japanese spicebush), herbs (e.g., rosemary, mint, basil, lemongrass, hops, jasmine, lavender, bergamot, lilac, and orange peel), tea (e.g., green tea, oolong tea, pu-erh tea, and black tea), grains (e.g., rice, barley, malt, and adlay), vegetables (e.g., tomatoes, eggplants, bell peppers, paprika, carrots, pumpkins, cucumbers, burdock, kidney beans, peas, soybeans, and sweet potatoes), fruits (e.g., pineapples, apples, strawberries, bananas, grapes, peaches, raspberries, cherries, blueberries, mangoes, oranges, lemons, grapefruits, and apricots), or ingredients such as the peels and seeds of vegetables and fruits. When added as a prepared liquid, the amount of water added refers to the water content contained in the prepared liquid. The amount of the above-mentioned materials mixed into the prepared liquid is not particularly limited and can be adjusted appropriately depending on the shape of the materials, etc. By using such a prepared liquid, the characteristic aroma of the above-mentioned materials can be efficiently imparted to green coffee beans. The spices, herbs, tea, grains, vegetables, fruits, vegetable and fruit skins and seeds, etc. that can be used as the above-mentioned materials can be appropriately selected depending on the desired aroma to be imparted to the green coffee beans, and commonly available materials can be used. The above-mentioned materials may be used in their original shape or size, or may be processed into a specific shape or size, but it is preferable to use them in any powder form because this facilitates mixing with water. As the above-mentioned materials, spices or herbs are preferably used because they are rich in aroma components and are excellent at improving or enhancing the coffee aroma.

[0022] (2) Step of Impregnating Green Coffee Beans with Water In the present invention, "heating the green coffee beans and water to a temperature of less than 100°C under atmospheric pressure to impregnate the green coffee beans with water" means that the green coffee beans and added water are heated from room temperature to a set temperature of less than 100°C without pressurizing them, and as a result, the added water is impregnated into the green coffee beans. At this time, water may adhere to the outer surface of the green coffee beans, and excess water may even be present outside the green coffee beans. In this specification, impregnating the green coffee beans with added water is sometimes referred to simply as "hydration."

[0023] More specifically, green coffee beans and a predetermined amount of added water are placed in a container (preferably a heat-resistant container) and heated, without pressurization, under atmospheric pressure to a set temperature from the temperature of the added water, for example, room temperature (1 to 35°C), to less than 100°C, thereby impregnating the green coffee beans with water. The upper limit of the set temperature is less than 100°C, preferably 99°C or less, and more preferably 95°C or less. The lower limit of the set temperature is not particularly limited as long as it is higher than room temperature, but in order to promote the impregnation of water into the green coffee beans, it is, for example, 35°C or higher, preferably 50°C or higher, and more preferably 60°C or higher. In the present invention, the set temperature range is, for example, 35°C or higher and less than 100°C, 35°C to 99°C, 40°C to 99°C, 50°C to 95°C, or 60°C to 95°C. The heating time and temperature rise profile for heating the green coffee beans and water are not particularly limited as long as the water is impregnated into the green coffee beans, and depend on the weight of the green coffee beans to be treated, but the lower limit is 5 minutes or more, preferably 10 minutes or more, and more preferably 15 minutes or more (e.g., 30 minutes or more). The upper limit is less than 16 hours, preferably 15 hours or less, more preferably 6 hours or less, and even more preferably 3 hours or less. If the heating time is 5 minutes or more, a sufficient amount of water is absorbed into the green coffee beans. In the present invention, the time for impregnating the green coffee beans with water is, for example, 5 minutes or more and less than 16 hours, 5 minutes to 15 hours, 5 minutes to 6 hours, 10 minutes to 3 hours, or 10 minutes to 2 hours, or 30 minutes or more and less than 16 hours.

[0024] Heating can be achieved by applying thermal energy to the green coffee beans and the coexisting moisture to raise the temperature inside the green coffee beans and the moisture. Examples of methods for applying thermal energy include a steaming method in which steam is directly applied to the green coffee beans, and a method in which the entire container is heated to raise the temperature of the green coffee beans and the moisture.

[0025] (3) Step of Absorbing Organic Acids and / or Sugars In the present invention, "absorb[ing] organic acids and / or sugars into green coffee beans" not only refers to adding organic acids and / or sugars to green coffee beans and then allowing the organic acids and / or sugars to be absorbed into the interior of the green coffee beans, but also includes attaching the organic acids and / or sugars to the outer surface of the green coffee beans, thereby creating a state in which the organic acids and / or sugars can act on the components of the green coffee beans.

[0026] The organic acid that can be used in the present invention is not particularly limited as long as it is edible. Examples of organic acids include lactic acid, citric acid, acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, gluconic acid, malic acid, tartaric acid, fumaric acid, succinic acid, and adipic acid. Lactic acid, citric acid, and acetic acid are preferred, and lactic acid is more preferred, due to their excellent inhibitory effect on the formation of indole and skatole. The sugars that can be used in the present invention are monosaccharides and disaccharides, with monosaccharides being preferred. Examples of monosaccharides include glucose (grape sugar), fructose (fruit sugar), galactose, xylose, arabinose, and tagatose, and examples of disaccharides include sucrose, lactose, maltose (malt sugar), isomaltose, trehalose, and cellobiose. Because of their excellent inhibitory effect on the formation of indole and skatole, glucose, fructose, and maltose are preferred, and fructose and glucose are more preferred. The organic acid may be used alone, or a combination of multiple organic acids may be used. When a combination of multiple organic acids is used, the types and ratios of the combined organic acids are not particularly limited. However, since the effect of inhibiting the formation of indole and skatole is excellent, the organic acid preferably contains one or more of lactic acid, citric acid, and acetic acid, more preferably at least lactic acid, even more preferably 30% by mass or more of lactic acid, and even more preferably 50% by mass or more of lactic acid. The sugar may be used alone, or multiple sugars may be used in combination. When a combination of multiple sugars is used, the types and ratios of the combined sugars are not particularly limited. However, since the effect of inhibiting the formation of indole and skatole is excellent, the sugar preferably contains one or more of glucose, fructose, and maltose, more preferably glucose or fructose, even more preferably at least glucose, even more preferably 30% by mass or more of glucose, and particularly preferably 50% by mass or more of glucose.

[0027] Patent Document 6 discloses soaking green coffee beans in sake lees to reduce aroma components, such as indole and skatole, which are believed to cause unpleasant odors in roasted coffee beans. Sake lees are known to contain various organic acids, sugars, amino acids, and other components (e.g., Non-Patent Documents 1 and 2). However, the organic acids and sugars contained in sake lees are very small; for example, lactic acid is approximately 74 mg / 100 g, acetic acid is approximately 30 mg / 100 g, and the total organic acid content is 189 to 418 mg / 100 g. Furthermore, glucose accounts for approximately 15%. Furthermore, the type and composition of components contained in sake lees are affected by various production conditions, such as the type and composition of fermentation raw materials, the type of koji mold used for koji, and fermentation conditions. Sake lees generally contain moisture, carbohydrates, proteins, lipids, ash, and various vitamins, but it has not been clarified which components contribute to the reduction of unpleasant odors.

[0028] Organic acids and / or sugars are added to the green coffee beans that have been impregnated with water as described above, and the organic acids and / or sugars are then allowed to penetrate into the interior of the green coffee beans and adhere to their outer surfaces. In this way, the organic acids and / or sugars that adhere to the interior and outer surfaces of the green coffee beans can act on the components of the green coffee beans. In the present invention, the total amount of organic acids and / or sugars that have penetrated into the interior of the green coffee beans and the amount of organic acids and / or sugars that have adhered to the outer surfaces of the green coffee beans is defined as the amount of organic acids and / or sugars absorbed by the green coffee beans.

[0029] The organic acids or sugars (total amount of organic acids or total amount of sugars) are absorbed at a lower limit of 0.5% by mass or more, preferably 0.7% by mass or more, and more preferably 1.0% by mass or more per mass of the green coffee beans before processing. The upper limit of the amount of organic acids or sugars absorbed per mass of the green coffee beans before processing is not limited, but is 10% by mass or less, or 5% by mass or less. Adding 10% by mass or less of organic acids or sugars allows the green coffee beans to absorb substantially all of the organic acids or sugars. Absorbing a total amount of 0.5% by mass or more of organic acids or sugars and processing under other conditions specified in the present invention significantly reduces the indole and skatole content in the roasted coffee beans compared to roasted coffee beans produced without treatment under all of the conditions specified in the present invention. In the present invention, the amount of organic acid or sugar added per mass of green coffee beans before processing is, for example, 0.5% by mass or more, 0.7% by mass or more, 1.0% by mass or more, 0.5 to 10% by mass, 0.7 to 10% by mass, 0.7 to 5% by mass, or 1.0 to 5% by mass. Organic acids and sugars may be used in combination, and when used in combination, the above amounts of each can be absorbed by the green coffee beans. When organic acids and sugars are used in combination, there are no particular limitations on the ratio (mass ratio) of organic acid to sugar, but for example, it is in the range of 99:1 to 1:99 organic acid:sugar, preferably in the range of 90:10 to 10:90, and more preferably in the range of 80:20 to 20:80.

[0030] In the step of adding the organic acid and / or sugar, the organic acid and / or sugar can be added directly to the coffee beans and absorbed, but adding an aqueous solution containing the organic acid and / or sugar to the green coffee beans allows for uniform absorption throughout. The concentration of the organic acid or sugar in the aqueous solution is not particularly limited, as long as a predetermined amount of organic acid and / or sugar is absorbed into the green coffee beans and adheres to their outer surfaces. For example, the lower limit of the concentration of the organic acid or sugar in the aqueous solution is 10% by mass or more, preferably 20% by mass or more, and more preferably 50% by mass or more. Although it depends on the amount of moisture already absorbed by the green coffee beans, as long as the concentration of the organic acid or sugar in the aqueous solution is 10% by mass or more, a predetermined amount of organic acid and / or sugar can be absorbed into the green coffee beans and adhered to their outer surfaces.

[0031] The conditions for the step of adding the organic acid and / or sugar, such as temperature and time, are not particularly limited as long as the organic acid and / or sugar is absorbed into the green coffee beans, and the step can be carried out under any conditions. For example, the temperature is from room temperature (1 to 35°C) to 90°C, preferably from 15 to 85°C, and the time is from 30 minutes to less than 16 hours, preferably from 30 minutes to 12 hours, and more preferably from 1 to 6 hours.

[0032] (4) Step of Roasting Green Coffee Beans That Have Absorbed Organic Acids and / or Sugars In the present invention, "roasting green coffee beans that have absorbed organic acids and / or sugars" means placing the green coffee beans in a roaster and adjusting the heat amount within the roaster to impart thermal energy to the green coffee beans. In the present invention, the roasting conditions, such as the roasting temperature and roasting environment, are not particularly limited as long as they are ordinary conditions, but the roasting conditions described in Non-Patent Document 3 can be referenced. By setting the roasting temperature to 190 to 240°C and controlling the temperature profile before and after roasting, it is possible to adjust flavors such as acidity, bitterness, and richness. In the present invention, the roasting degree of the roasted coffee beans is not particularly limited and is defined by the L value measured under the following conditions. The L value is the "L" value representing brightness in the Lab standard established by the International Commission on Illumination. The reference L value for the degree of roasting is, for example, 27.0 or more for light roast, 18.5 or more and less than 20.5 for medium roast (city roast), and 15.0 or more and less than 16.5 for dark roast (French roast). In the present invention, the roasting device and heating method are not particularly limited, and known roasting devices and heating methods such as direct flame type, semi-hot air type, and hot air type can be used.

[0033] (5) Step of Drying the Green Coffee Beans That Have Absorbed Organic Acids and / or Sugars After the step of absorbing organic acids and / or sugars, the green coffee beans that have absorbed moisture in the above steps can be dried and then roasted, or the green coffee beans can be roasted without drying. The drying method for drying the green coffee beans is not particularly limited and can be determined appropriately by those skilled in the art. For example, the green coffee beans can be dried with hot air in a food dryer, or by fluidized bed drying or natural drying. The drying conditions can be determined appropriately by those skilled in the art, but can be, for example, dried at 60°C to 80°C for 1 to 4 hours. The degree of drying may be approximately the same as the moisture content of the green coffee beans before processing (e.g., 9 to 13% by mass), or can be adjusted to a moisture content different from that of the green beans before processing, depending on the roasting step. In the present invention, a drying step is not required; the wet green coffee beans may be directly subjected to the roasting step. By appropriately setting the roasting conditions according to the wetness and dryness of the green coffee beans, roasted coffee beans of the desired roasting level can be obtained.

[0034] It was confirmed that the roasted coffee beans obtained in this manner had significantly reduced content of indole and skatole, which are unpleasant odor components, compared to roasted coffee beans produced by conventional manufacturing methods, and had an improved flavor evaluation rank.

[0035] Hereinafter, the present invention will be described using control examples, examples, and comparative examples, but the present invention is not limited to these, and it should be understood that any modifications or additions may be made and the present invention may be used in combination with other techniques as long as they do not impede the object of the present invention.

[0036] Experiment 1: Effect of Adding Organic Acids to Green Coffee Beans (1) Roasted Coffee Beans [Control A] 100 g of Robusta green coffee beans (produced in Vietnam) were roasted using a Gene Cafe (manufactured by Genesis) at 235°C until an L value of 20 was reached, yielding roasted coffee beans (Vietnamese Robusta Control A). [Control B] 100 g of Robusta green coffee beans (produced in Vietnam) and 40 g of room temperature water were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and held at that temperature for 30 minutes for a heating treatment. The coffee beans were then dried to a moisture content similar to that before processing, and the resulting dried green coffee beans were roasted using a Gene Cafe (manufactured by Genesis) at 235°C until an L value of 20 was reached, yielding roasted coffee beans (Vietnamese Robusta Control B). In the experimental section, the roasting conditions were standardized to a medium roast with an L value of 20 to facilitate the identification of changes in the indole and skatole content in the roasted coffee beans. However, the roasting level is not limited in the present invention. [Samples 1-1 to 1-3] 100 g of Robusta coffee beans (produced in Vietnam) and 40 g of room-temperature water were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and held at that temperature for 30 minutes to perform a heating treatment. 3 g of organic acid (lactic acid, citric acid, or acetic acid) was added to 100 g of unprocessed green coffee beans and allowed to stand at room temperature for 3 hours to absorb. Thereafter, the coffee beans were dried until the moisture content was approximately the same as before processing, and the resulting dried processed green coffee beans were roasted at 235°C using a Gene Cafe (manufactured by Genesis) until the L value reached 20, thereby obtaining roasted coffee beans (Vietnamese Robusta samples 1-1 to 1-3).

[0037] (2) Coffee Extract For Controls A and B and Samples 1-1 to 1-3, each roasted coffee bean was finely ground using a cone grinder (DeLonghi SpA) to obtain a roasted bean powder. 180 mL of hot water was poured over 10 g of the roasted bean powder and held for 4 minutes, after which the whole was stirred to remove any remaining foam on the surface. The mixture was then held for 12 minutes after pouring the hot water (i.e., the extraction time was set to 12 minutes), and the supernatant liquid after natural settling of the roasted bean powder was collected and used as a coffee extract.

[0038] (3) Measurement of Indole and Skatole Content in Coffee Extracts 3-Methyl-1H-indole-d8 (obtained from Toronto Research Chemicals Inc.) was dissolved in 50% by volume aqueous methanol to a concentration of 100 ng / mL to prepare an internal standard solution. 25 μL of this internal standard solution, 400 μL of 50% by volume aqueous methanol, and 100 μL of each coffee extract were mixed and filtered through a 0.2 μm pore PTFE filter, and the filtrate was used as the analytical sample. The indole and skatole contents of the analytical samples were measured according to the following LC-MS / MS conditions. Three data points per condition were used, and the average was calculated to obtain the quantitative value.

[0039] (4) Measurement Results Table 1 summarizes the quantitative values ​​and standard deviations of indole and skatole for each sample, and Figure 1 shows a graph comparing the quantitative values ​​of indole (upper row) and skatole (lower row) for each sample.

[0040]

[0041] (5) Discussion It was confirmed that the indole or skatole content in the extract obtained from the green coffee beans of the Examples processed by adding water, heating, and an organic acid was significantly reduced compared to the extract obtained from either of the Control Examples. In particular, it was confirmed that the indole or skatole content was significantly reduced when lactic acid was used as the organic acid.

[0042] Experiment 2 Effect of Water Amount Added to Green Coffee Beans (1) Roasted Coffee Beans [Sample 2-1] 100 g of Robusta green coffee beans (produced in Vietnam) were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and maintained at that temperature for 30 minutes for a heating treatment. 3 g of lactic acid was added to the heated green coffee beans per 100 g of unprocessed green coffee beans, and the beans were allowed to absorb at room temperature for 3 hours. The coffee beans were then dried to a moisture content similar to that before processing, and the resulting dried green coffee beans were roasted at 235°C using a Gene Cafe (manufactured by Genesis) until an L value of 20 was reached, yielding roasted coffee beans (Robusta green coffee beans produced in Vietnam, Sample 2-1). [Samples 2-2 to 2-8] 100 g of Robusta coffee beans (produced in Vietnam) and 10 g, 20 g, 30 g, 40 g, 50 g, 60 g, or 100 g of room-temperature water were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and held at that temperature for 30 minutes for a heating treatment. Roasted coffee beans (Vietnamese Robusta Samples 2-2 to 2-8) were obtained in the same manner as Sample 2-1, except for the above. [Sample 2-9] 100 g of Robusta coffee beans (produced in Vietnam) and 40 g of room-temperature water were placed in a heat-resistant container, and roasted coffee beans (Vietnamese Robusta Sample 2-9) were obtained in the same manner as Sample 2-1, except for the heating treatment.

[0043] (2) Coffee Extract Samples 2-1 to 2-9 were treated in the same manner as Controls A and B to prepare coffee extracts.

[0044] (3) Measurement of indole and skatole contents in coffee extracts The indole and skatole contents of Samples 2-1 to 2-9 were measured in the same manner as for Controls A and B. Three data points per condition were obtained, and the average values ​​were calculated to obtain quantitative values.

[0045] (4) Measurement Results Table 2 summarizes the quantitative values ​​and standard deviations of indole and skatole for each sample, and Figure 2 shows a graph comparing the quantitative values ​​of indole (upper row) and skatole (lower row) for each sample.

[0046]

[0047] (5) Discussion It was confirmed that the indole or skatole content in the extract obtained from the green coffee beans of the Examples, which were processed by adding 10% by mass or more of water, heating, and adding an organic acid, was significantly reduced compared to the extracts obtained from any of the Control Examples and Comparative Examples.

[0048] Experiment 3: Effect of the Amount of Organic Acid Added to Green Coffee Beans (1) Roasted Coffee Beans [Samples 3-1 to 3-4] 100 g of Robusta green coffee beans (produced in Vietnam) and 40 g of room-temperature water were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and held at that temperature for 30 minutes for a heating treatment. 0.7, 1, 3, or 5 g of lactic acid per 100 g of unprocessed green coffee beans was added to the heated green coffee beans and allowed to absorb at room temperature for 3 hours. The coffee beans were then dried to a moisture content similar to that before processing, and the resulting dried processed green coffee beans were roasted at 235°C to an L value of 20 using a Gene Cafe (manufactured by Genesis) to obtain roasted coffee beans (Robusta green coffee beans produced in Vietnam, Samples 3-1 to 3-4).

[0049] (2) Coffee Extract Samples 3-1 to 3-4 were treated in the same manner as Controls A and B to prepare coffee extracts.

[0050] (3) Measurement of indole and skatole contents in coffee extracts The indole and skatole contents of Samples 3-1 to 3-4 were measured in the same manner as for Controls A and B. Three data points per condition were obtained, and the average values ​​were calculated to obtain quantitative values.

[0051] (4) Evaluation Results Table 3 summarizes the quantitative values ​​and standard deviations of indole and skatole for each sample, and FIG. 3 shows a graph comparing the quantitative values ​​of indole (upper row) and skatole (lower row) for each sample.

[0052]

[0053] (5) Discussion It was confirmed that the indole or skatole content in the extract obtained from the green coffee beans of the Examples, which were processed by adding water, heating, and adding 0.7% by mass or more of an organic acid, was significantly reduced compared to the extracts obtained from either of the Control Examples.

[0054] Experiment 4 Effect of Adding Sugars to Green Coffee Beans (1) Roasted Coffee Beans [Samples 4-1 to 4-3] 100 g of Robusta green coffee beans (produced in Vietnam) and 40 g of room-temperature water were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and maintained at that temperature for 30 minutes for heating treatment. 3 g of sugars (fructose, maltose, or glucose) per 100 g of unprocessed green coffee beans were added to the heated green coffee beans and allowed to absorb at room temperature for 3 hours. The coffee beans were then dried to a moisture content similar to that before processing, and the resulting dried processed green coffee beans were roasted at 235°C to an L value of 20 using a Gene Cafe (manufactured by Genesis) to obtain roasted coffee beans (Robusta green coffee beans produced in Vietnam, Samples 4-1 to 4-3).

[0055] (2) Coffee Extract Samples 4-1 to 4-3 were treated in the same manner as Controls A and B to prepare coffee extracts.

[0056] (3) Measurement of indole and skatole contents in coffee extracts The indole and skatole contents of Samples 4-1 to 4-3 were measured in the same manner as for Controls A and B. Three data points per condition were obtained, and the average values ​​were calculated to obtain quantitative values.

[0057] (4) Evaluation Results Table 4 summarizes the quantitative values ​​and standard deviations of indole and skatole for each sample, and FIG. 4 shows a graph comparing the quantitative values ​​of indole (upper row) and skatole (lower row) for each sample.

[0058]

[0059] (5) Discussion It was confirmed that the indole or skatole content in the extract obtained from the green coffee beans of the Examples processed by adding water, heating, and sugar was significantly reduced compared to the extract obtained from either of the Control Examples. In particular, it was confirmed that the indole or skatole content was further reduced when fructose or glucose was used as the sugar.

[0060] Experiment 5 Effect of Water Amount Added to Green Coffee Beans (1) Roasted Coffee Beans [Sample 5-1] 100 g of Robusta green coffee beans (produced in Vietnam) were placed in a heat-resistant container and covered with aluminum foil to prevent moisture loss. The heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and maintained at that temperature for 30 minutes for a heating treatment. 3 g of glucose was added to the heated green coffee beans per 100 g of unprocessed green coffee beans and allowed to absorb at room temperature for 3 hours. The coffee beans were then dried to a moisture content similar to that before processing, and the resulting dried green coffee beans were roasted at 235°C using a Gene Cafe (manufactured by Genesis) until an L value of 20 was reached, yielding roasted coffee beans (Robusta green coffee beans produced in Vietnam, Sample 5-1). [Samples 5-2 to 5-8] 100 g of Robusta coffee beans (produced in Vietnam) and 10 g, 20 g, 30 g, 40 g, 50 g, 60 g, or 100 g of room-temperature water were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and held at that temperature for 30 minutes for a heating treatment. Roasted coffee beans (Vietnamese Robusta Samples 5-2 to 5-8) were obtained in the same manner as Sample 5-1, except for the above. [Sample 5-9] 100 g of Robusta coffee beans (produced in Vietnam) and 40 g of room-temperature water were placed in a heat-resistant container, and roasted coffee beans (Vietnamese Robusta Sample 5-9) were obtained in the same manner as Sample 5-1, except for the heating treatment.

[0061] (2) Coffee Extract Samples 5-1 to 5-9 were treated in the same manner as Controls A and B to prepare coffee extracts.

[0062] (3) Measurement of indole and skatole contents in coffee extracts The indole and skatole contents of Samples 5-1 to 5-9 were measured in the same manner as for Controls A and B. Three data points per condition were obtained, and the average values ​​were calculated to obtain quantitative values.

[0063] (4) Measurement Results Table 5 summarizes the quantitative values ​​and standard deviations of indole and skatole for each sample, and FIG. 5 shows a graph comparing the quantitative values ​​of indole (upper row) and skatole (lower row) for each sample.

[0064]

[0065] (5) Discussion It was confirmed that the indole or skatole content in the extract obtained from the green coffee beans of the Examples, which were processed by adding 10% by mass or more of water, heating, and adding sugars, was significantly reduced compared to the extracts obtained from any of the Control Examples and Comparative Examples.

[0066] Experiment 6: Effect of Sugar Amount Added to Green Coffee Beans (1) Roasted Coffee Beans [Samples 6-1 to 6-4] 100 g of Robusta green coffee beans (produced in Vietnam) and 40 g of room-temperature water were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and held at that temperature for 30 minutes for heating treatment. 0.7, 1, 3, or 5 g of glucose per 100 g of unprocessed green coffee beans was added to the heated green coffee beans and allowed to absorb at room temperature for 3 hours. The coffee beans were then dried to a moisture content similar to that before processing, and the resulting dried processed green coffee beans were roasted at 235°C to an L value of 20 using a Gene Cafe (manufactured by Genesis) to obtain roasted coffee beans (Robusta green coffee beans produced in Vietnam, Samples 6-1 to 6-4).

[0067] (2) Coffee Extract Samples 6-1 to 6-4 were treated in the same manner as Controls A and B to prepare coffee extracts.

[0068] (3) Measurement of indole and skatole contents in coffee extracts The indole and skatole contents of Samples 6-1 to 6-4 were measured in the same manner as for Controls A and B. Three data points per condition were obtained, and the average values ​​were calculated to obtain quantitative values.

[0069] (4) Evaluation Results Table 6 summarizes the quantitative values ​​and standard deviations of indole and skatole for each sample, and FIG. 6 shows a graph comparing the quantitative values ​​of indole (upper row) and skatole (lower row) for each sample.

[0070]

[0071] (5) Discussion It was confirmed that the indole or skatole content in the extract obtained from the green coffee beans of the Examples, which were processed by adding water, heating, and adding 0.7% by mass or more of sugars, was significantly reduced compared to the extracts obtained from either of the Control Examples.

[0072] Experiment 7: Effect of Adding Organic Acids and Sugars to Green Coffee Beans (1) Roasted Coffee Beans [Samples 7-1 to 7-4] 100 g of Robusta green coffee beans (from Vietnam) and 40 g of room-temperature water were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and held at that temperature for 30 minutes for heating treatment. For 100 g of unprocessed green coffee beans, 0.7 g of lactic acid and 0.7 g of glucose, 1 g of lactic acid and 1 g of glucose, 3 g of lactic acid and 3 g of glucose, or 5 g of lactic acid and 10 g of glucose were added to the heated green coffee beans, and the beans were left at room temperature for 3 hours to absorb the added sugars. Thereafter, the coffee beans were dried until the moisture content was approximately the same as before processing, and the obtained dried processed green coffee beans were roasted at 235°C using a Gene Cafe (manufactured by Genesis) until the L value reached 20, thereby obtaining roasted coffee beans (Vietnamese Robusta samples 7-1 to 7-4).

[0073] (2) Coffee Extract Samples 7-1 to 7-4 were treated in the same manner as Controls A and B to prepare coffee extracts.

[0074] (3) Measurement of indole and skatole contents in coffee extracts The indole and skatole contents of Samples 7-1 to 7-4 were measured in the same manner as for Controls A and B. Three data points per condition were obtained, and the average values ​​were calculated to obtain quantitative values.

[0075] (4) Evaluation Results Table 7 summarizes the quantitative values ​​and standard deviations of indole and skatole for each sample, and FIG. 7 shows a graph comparing the quantitative values ​​of indole (upper row) and skatole (lower row) for each sample.

[0076]

[0077] (5) Discussion It was confirmed that the indole or skatole content in the extract obtained from the green coffee beans of the Examples, which were processed by adding water, heating, and adding organic acids and sugars, was significantly reduced compared to the extracts obtained from either of the Control Examples.

[0078] Experiment 8: Effect of Water Amount Added to Green Coffee Beans (1) Roasted Coffee Beans [Sample 8-1] 100 g of Robusta green coffee beans (from Vietnam) were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and maintained at that temperature for 30 minutes for heating processing. For 100 g of unprocessed green coffee beans, 3 g of an organic acid mixture (lactic acid:acetic acid:citric acid = 4:1:1 by mass) and 3 g of glucose were added to the heated green coffee beans, and the beans were allowed to absorb at room temperature for 3 hours. The coffee beans were then dried to a moisture content similar to that before processing, and the resulting dried green coffee beans were roasted at 235°C using a Gene Cafe (manufactured by Genesis) until an L value of 20 was reached, yielding roasted coffee beans (Robusta green coffee beans from Vietnam, Sample 8-1). [Samples 8-2 to 8-8] 100 g of Robusta coffee beans (produced in Vietnam) and 10 g, 20 g, 30 g, 40 g, 50 g, 60 g, or 100 g of room-temperature water were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and maintained at that temperature for 30 minutes for a heating treatment. Roasted coffee beans (Vietnamese Robusta Samples 8-2 to 8-8) were obtained in the same manner as Sample 8-1, except for the above. [Sample 8-9] 100 g of Robusta coffee beans (produced in Vietnam) and 40 g of room-temperature water were placed in a heat-resistant container, and roasted coffee beans (Vietnamese Robusta Sample 8-9) were obtained in the same manner as Sample 8-1, except for the heating treatment.

[0079] (2) Coffee Extract Samples 8-1 to 8-9 were treated in the same manner as Controls A and B to prepare coffee extracts.

[0080] (3) Measurement of indole and skatole contents in coffee extracts The indole and skatole contents of Samples 8-1 to 8-9 were measured in the same manner as for Controls A and B. Three data points per condition were obtained, and the average values ​​were calculated to obtain quantitative values.

[0081] (4) Measurement Results Table 8 summarizes the quantitative values ​​and standard deviations of indole and skatole for each sample, and FIG. 8 shows a graph comparing the quantitative values ​​of indole (upper row) and skatole (lower row) for each sample.

[0082]

[0083] (5) Discussion It was confirmed that the indole or skatole content in the extract obtained from the green coffee beans of the Examples, which were processed by adding 10% by mass or more of water, heating, and adding organic acids and sugars, was significantly reduced compared to the extracts obtained from any of the Control Examples and Comparative Examples.

[0084] Experiment 9: Effect of Adding Organic Acids and Sugars to Green Coffee Beans (1) Roasted Coffee Beans [Control C] 100 g of Robusta coffee beans (Ugandan) were roasted at 235°C using a Gene Cafe (manufactured by Genesis) until an L value of 20 was reached, yielding roasted coffee beans (Ugandan Robusta Control C). [Sample 9-1] 100 g of Robusta coffee beans (Ugandan) and 40 g of room-temperature water were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and held at that temperature for 30 minutes for heating treatment. For 100 g of unprocessed green coffee beans, 3 g of an organic acid mixture (lactic acid:acetic acid:citric acid = 4:1:1 by mass) and 3 g of glucose were added to the heated green coffee beans, and the beans were left at room temperature for 3 hours for absorption. The coffee beans were then dried until their moisture content was approximately the same as before processing, and the resulting dried processed green coffee beans were roasted using a Gene Cafe (manufactured by Genesis) at 235°C until an L value of 20 was reached, yielding roasted coffee beans (Ugandan Robusta Sample 9-1). [Control D] 100g of Robusta green coffee beans (produced in Indonesia) were roasted using a Gene Cafe (manufactured by Genesis) at 235°C until an L value of 20 was reached, yielding roasted coffee beans (Indonesian Robusta Control D). [Sample 9-2] 100g of Robusta green coffee beans (produced in Indonesia) and 40g of water at room temperature were placed in a heat-resistant container, the container was covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), the temperature was raised from room temperature to 90°C, and the container was maintained at that temperature for 30 minutes, thereby carrying out a heating treatment. To 100 g of unprocessed green coffee beans, 3 g of an organic acid mixture (lactic acid:acetic acid:citric acid = 4:1:1 mass ratio) and 3 g of glucose were added, and the beans were left to absorb at room temperature for 3 hours. The coffee beans were then dried to a moisture content similar to that before processing, and the resulting dried processed green coffee beans were roasted at 235°C using a Gene Cafe (manufactured by Genesis) until an L value of 20 was reached, yielding roasted coffee beans (Indonesian Robusta sample 9-2).

[0085] (2) Coffee Extract For Control C, Sample 9-1, Control D, and Sample 9-2, roasted coffee beans were finely ground using a cone grinder (DeLonghi SpA) to obtain roasted bean powder. 180 mL of hot water was poured over 10 g of roasted bean powder and held for 4 minutes, after which the mixture was stirred to remove any remaining foam on the surface. The mixture was then held for 12 minutes after pouring the hot water (i.e., the extraction time was set to 12 minutes), and the supernatant liquid after natural settling of the roasted bean powder was collected and used as the coffee extract.

[0086] (3) Measurement of Indole and Skatole Content in Coffee Extracts 3-Methyl-1H-indole-d8 (obtained from Toronto Research Chemicals Inc.) was dissolved in 50% by volume aqueous methanol to a concentration of 100 ng / mL to prepare an internal standard solution. 25 μL of this internal standard solution, 400 μL of 50% by volume aqueous methanol, and 100 μL of each coffee extract were mixed and filtered through a 0.2 μm pore PTFE filter, and the filtrate was used as the analytical sample. The indole and skatole contents of the analytical samples were measured according to the following LC-MS / MS conditions. Three data points per condition were used, and the average was calculated to obtain the quantitative value.

[0087] (4) Measurement Results Table 9 summarizes the quantitative values ​​and standard deviations of indole and skatole for each sample, and Figure 9 shows a graph comparing the quantitative values ​​of indole (upper row) and skatole (lower row) for each sample.

[0088]

[0089] (5) Discussion It was confirmed that, regardless of the origin of the coffee beans, the content of indole or skatole in the extract obtained from the green coffee beans of the Examples, which were processed by adding water, heating, and organic acids and sugars, was significantly reduced compared to the extract obtained from any of the Control Examples.

[0090] Experiment 10: Effect of Adding Organic Acids and Sugars to Green Coffee Beans (1) Roasted Coffee Beans [Control E] 100 g of green Arabica coffee beans (Brazilian) were roasted at 235°C using a Gene Cafe (manufactured by Genesis) until an L value of 20 was reached, yielding roasted coffee beans (Brazilian Arabica Control E). [Sample 10-1] 100 g of green Arabica coffee beans (Brazilian) and 40 g of room-temperature water were placed in a heat-resistant container, covered with aluminum foil to prevent moisture loss, and the heat-resistant container was placed in an autoclave (LSX500, Tomy Seiko Co., Ltd.), heated from room temperature to 90°C, and held at that temperature for 30 minutes for heating treatment. For 100 g of unprocessed green coffee beans, 3 g of an organic acid mixture (lactic acid:acetic acid:citric acid = 4:1:1 by mass) and 3 g of glucose were added to the heated green coffee beans, and the beans were left at room temperature for 3 hours for absorption. The coffee beans were then dried until their moisture content was approximately the same as before processing, and the resulting dried processed green coffee beans were roasted using a Gene Cafe (manufactured by Genesis) at 235°C until an L value of 20 was reached, yielding roasted coffee beans (Brazilian Arabica Sample 10-1). [Sample 10-2] 100 g of green Arabica coffee beans (from Brazil) were placed in a heat-resistant container, and roasted coffee beans (Brazilian Arabica Sample 10-2) were obtained in the same manner as Sample 10-1, except that no water was added. [Sample 10-3] 100 g of green Arabica coffee beans (from Brazil) and 40 g of room temperature water were placed in a heat-resistant container, and roasted coffee beans (Brazilian Arabica Sample 10-3) were obtained in the same manner as Sample 10-1, except that no heating treatment was performed. [Sample 10-4] Roasted coffee beans (Brazilian Arabica sample 10-4) were obtained in the same manner as Sample 10-1, except that neither organic acids nor sugars were added to the heat-treated green coffee beans.

[0091] (2) Coffee Extract For Control E and Samples 10-1 to 10-4, roasted coffee beans were finely ground using a cone grinder (DeLonghi SpA) to obtain roasted bean powder. 180 mL of hot water was poured over 10 g of roasted bean powder and held for 4 minutes, after which the mixture was stirred to remove any remaining foam on the surface. The mixture was then held for 12 minutes after pouring the hot water (i.e., the extraction time was set to 12 minutes), and the supernatant liquid after natural settling of the roasted bean powder was collected and used as the coffee extract.

[0092] (3) Measurement of Indole and Skatole Content in Coffee Extracts 3-Methyl-1H-indole-d8 (obtained from Toronto Research Chemicals Inc.) was dissolved in 50% by volume aqueous methanol to a concentration of 100 ng / mL to prepare an internal standard solution. 25 μL of this internal standard solution, 400 μL of 50% by volume aqueous methanol, and 100 μL of each coffee extract were mixed and filtered through a 0.2 μm pore PTFE filter, and the filtrate was used as the analytical sample. The indole and skatole contents of the analytical samples were measured according to the following LC-MS / MS conditions. Three data points per condition were used, and the average was calculated to obtain the quantitative value.

[0093] (4) Measurement Results Table 10 summarizes the quantitative values ​​and standard deviations of indole and skatole for each sample, and FIG. 10 shows a graph comparing the quantitative values ​​of indole (upper row) and skatole (lower row) for each sample.

[0094]

[0095] (5) Discussion It was confirmed that, regardless of the variety of coffee beans, the content of indole or skatole in the extract obtained from the green coffee beans of the Examples that were processed by adding water, heating, and adding organic acids and sugars was significantly reduced compared to the extracts obtained from any of the Control Examples and Comparative Examples.

[0096] Experiment 11 Effect of Presence or Absence of Drying After Allowing Green Coffee Beans to Absorb Organic Acids and Sugars (1) Roasted Coffee Beans [Sample 11] (1) Roasted Coffee Beans An organic acid mixture (lactic acid:acetic acid:citric acid = 4:1:1 mass ratio) and glucose were added to warmed green coffee beans, which were then left to absorb at room temperature for 3 hours. Roasted coffee beans (Vietnamese Robusta Sample 11) were obtained in the same manner as Sample 8-5, except that they were not dried.

[0097] (2) Coffee Extract Sample 11 was treated in the same manner as Controls A and B to prepare a coffee extract.

[0098] (3) Measurement of indole and skatole contents in coffee extract The indole and skatole contents of Sample 11 were measured in the same manner as for Controls A and B. Three data points per condition were obtained, and the average values ​​were calculated to obtain quantitative values.

[0099] (4) Measurement Results Table 11 summarizes the quantitative values ​​and standard deviations of indole and skatole for each sample, and FIG. 11 shows a graph comparing the quantitative values ​​of indole (upper row) and skatole (lower row) for each sample.

[0100]

[0101] (5) Discussion It was confirmed that the indole or skatole content in the extract obtained from the green coffee beans of the Examples, which were processed by adding water, heating, and adding organic acids and sugars, was significantly reduced compared to the extract obtained from either of the Control Examples, regardless of whether the beans were dried after absorbing the organic acids and sugars.

[0102] [Measurement Method] <LC-MS / MS Conditions> A quantitative method was established using multiple reaction monitoring mode with 3-methyl-1H-indole-d8 as the internal standard. Indole (obtained from Nacalai Tesque) and skatole (obtained from Tokyo Chemical Industry Co., Ltd.) were each diluted with 50% by volume of aqueous methanol, and calibration curves for each compound were prepared. The compound concentrations in coffee extract samples pretreated using the above method were then quantified. Specifically, a Shimadzu Shim-pack Scepter C18-120 column (1.9 μm, 2.1 mm × 50 mm) was used. The LC-MS / MS equipment used included a Shimadzu Nextera HPLC system (communication bus module: CBM-20A; pump: LC-30AD; autosampler: SIL-30AC; degasser: DGU-20A5R; column oven: CTO-20AC) for high-performance liquid chromatography (HPLC) and an AB SCIEX Sciex Triple quad 6500+ tandem mass spectrometry (MS / MS) system. Mobile phase A consisted of 0.05% by volume formic acid in water, and mobile phase B consisted of 100% by volume methanol. The flow rate was 0.2 mL / min, and the column temperature was set to 40°C. The initial concentration was 45:55 by volume of mobile phase A:B, and the same conditions were maintained for 5 minutes. After 0.1 minutes, the mobile phase A:B volume ratio was changed to 0:100, and the same conditions were maintained for 2 minutes. The injection volume into the HPLC was 2 μL. The MS conditions were APCI positive ionization mode, and the following six MS conditions were common parameters for all compounds: curtain gas, collision activated dissociation gas, ion spray voltage floating, temperature, ion source gas 1, and entrance potential, which are summarized in Table 12.The following six MS conditions: declustering potential, collision energy, collision cell exit potential, elution time, precursor ion, and product ion are parameters set for each compound and are summarized in Table 13.

[0103]

[0104]

[0105] <Method for Measuring L Value> The L value was measured using a color meter ZE6000 manufactured by Nippon Denshoku Industries Co., Ltd. Specifically, 10 g of roasted coffee beans were finely ground using a cone grinder (DeLonghi SpA), and the resulting powder was placed in an attached round cell and compressed, and the L value was measured in the reflection mode of the color meter.

[0106] In conventional technology, green coffee beans need to be heat-treated at high temperatures of 100°C or higher, necessitating the use of high-pressure heating equipment. However, the method for reducing indole and skatole in roasted coffee beans according to the present invention makes it possible to suppress the formation of specific unpleasant-odor components (indole and skatole) that occur in roasted coffee beans in a short period of time under heating conditions of less than 100°C. Thus, the method for producing roasted coffee beans according to the present invention employs the above-mentioned reduction method and can produce roasted coffee beans with significantly reduced contents of the unpleasant-odor components indole and skatole, using simple equipment.

Claims

1. A method for producing roasted coffee beans, (1) A step of adding 10% by mass or more of moisture to the green coffee beans; (2) After the step of adding water, the step of heating the green coffee beans and water to a temperature of less than 100°C under atmospheric pressure to impregnate the green coffee beans with water; (3) A step after the step of impregnating with water, in which organic acids and / or sugars are absorbed into the water-impregnated green coffee beans; and (4) After the step of absorbing the organic acid and / or sugars, the step of roasting the green coffee beans that have absorbed the organic acid and / or sugars. A method for producing roasted coffee beans, including [the specified ingredient].

2. The manufacturing method according to claim 1, wherein in the step of absorbing the organic acid and / or sugars, the water-impregnated green coffee beans are impregnated with an aqueous solution containing an organic acid and / or sugars.

3. The method for producing a product according to claim 1, wherein the organic acid is at least one selected from the group consisting of lactic acid, citric acid, and acetic acid, and the sugar is at least one selected from the group consisting of glucose, fructose, and maltose.

4. The manufacturing method according to claim 1, wherein 0.5% by mass or more of an organic acid or sugar is absorbed with respect to the green coffee beans.

5. The manufacturing method according to claim 1, wherein the green coffee beans are of the Robusta variety.

6. Roasted coffee beans produced by the manufacturing method described in any one of claims 1 to 5.

7. Food or beverage containing roasted coffee beans or an extract thereof as described in claim 6.

8. A method for reducing indole and skatole in roasted coffee beans, (1) A step of adding 10% by mass or more of moisture to the green coffee beans; (2) After the step of adding water, the step of heating the green coffee beans and water to a temperature of less than 100°C under atmospheric pressure to impregnate the green coffee beans with water; (3) A step after the step of impregnating with water, in which organic acids and / or sugars are absorbed into the water-impregnated green coffee beans; and (4) After the step of absorbing the organic acid and / or sugars, the step of roasting the green coffee beans that have absorbed the organic acid and / or sugars. A method for reducing indole and skatole in roasted coffee beans, including [the specified substance].