Roasted coffee beans, roasted coffee bean aging method, aged roasted coffee beans, and packaged aged roasted coffee beans

Abstract

To provide roasted coffee beans which can be stored for a long period without deteriorating in taste even at room temperature after roasting, and a method for aging the roasted coffee beans. (A) The pore volume calculated by the nitrogen BJH method is 1.5 × 10 -3 cm 3 / g or more 3.0×10 -3 cm 3 / g or less, and (B) the total volume of pores having a diameter of 20 Å to 200 Å calculated by the nitrogen BJH method is 1.5 × 10 -3 cm 3 / g or more, and roasted coffee beans having a texture are subjected to an oxygen permeability test at 5000cm 3 / m 2 ·24h · ATM or more 20000cm 3 / m 2 Aging the beans in a storage container at or below 24 hours atm reduces the bitterness and produces matured roasted coffee beans with a clean taste. It also reduces the amount of diacetyl, which can be harmful to your health.

Description

[Technical Field]

[0001] The present invention relates to roasted coffee beans that can be stored for long periods at room temperature, a method for aging roasted coffee beans, aged roasted coffee beans, and packaged aged roasted coffee beans. More specifically, the present invention relates to aged roasted coffee beans that have a predetermined texture and are aged in a storage container with a predetermined oxygen permeability, thereby improving the aroma and flavor and reducing the diacetyl content that causes health problems. [Background technology]

[0002] Coffee beans have almost no flavor or aroma when they are in their green state, but roasting produces the aroma components characteristic of coffee. Lightly roasted coffee beans have a sour taste due to the acidity inherent in the green beans. On the other hand, darkly roasted coffee beans have a fragrant roasted aroma and a bitter taste due to the roasting, but if they are roasted too much, they tend to have a strong, stinging bitterness in the mouth rather than umami. In this way, the roasting conditions determine the characteristics and quality of the roasted coffee beans, and ultimately affect the characteristics and quality of the extracted drip coffee.

[0003] For example, Patent Document 1 discloses a roasting method in which roasting is performed in two stages using the roast color or temperature of coffee beans as an indicator, thereby enhancing methanethiol (methyl mercaptan), which contributes to the fresh aroma of roasted beans, thereby improving the production of aromas and flavors characteristic of coffee. Patent Document 2 also discloses a roasting method that includes a step of rapidly heating the coffee beans at a high heating rate (20°C / min to 40°C / min) until the temperature of the coffee beans reaches 160°C to 220°C, and a step of gradually heating the beans at a low heating rate (1°C / min to 10°C / min), thereby reducing acrylamide produced by roasting coffee beans while maintaining the flavor characteristics of coffee.

[0004] Generally, roasted coffee beans are best enjoyed within three days to three to five weeks after roasting. Immediately after roasting, coffee beans retain a roasted aroma and have not yet released carbon dioxide, which can affect extraction. Carbon dioxide generated by the coffee beans can interfere with extraction, resulting in a bland flavor or, conversely, an overly bitter taste, making it difficult to obtain the original flavor of the beans. For this reason, after roasting, the roasted coffee beans are allowed to degas at room temperature for one to three days before being extracted. On the other hand, when roasted coffee beans are stored for a long period of time, the aroma components produced by roasting are lost, and the oils contained in the coffee beans deteriorate, increasing an unpleasant sourness. The flavor tends to deteriorate significantly within one month of roasting.

[0005] The factors that cause roasted coffee beans to deteriorate are air, moisture, temperature changes, and light. To minimize these effects, it is recommended to store them in an airtight package after roasting. The shelf life of coffee beans after opening the package is about one week for ground coffee and about one month for whole beans. After opening the package, it is recommended to store them in the refrigerator or freezer and consume them as soon as possible.

[0006] Commercially available roasted coffee beans are typically sealed and packed in aluminum-coated laminated packaging (aluminized bags) to extend their shelf life as much as possible. Because aluminum-coated bags have virtually no air permeability, the roasted coffee beans gradually release carbon dioxide during storage, which can cause the package to expand and burst. For this reason, a gas release valve is provided to prevent bursting. The shelf life of roasted coffee beans packed in such aluminum-coated bags with a gas release valve is set at approximately three to six months in an unopened state at specialty coffee shops, while supermarkets and major coffee chains often set it at approximately one year.

[0007] However, even if the beans are packed in aluminum-coated bags, which are considered to have a long shelf life, the flavor still deteriorates about a month after roasting. This is why it is recommended to buy coffee beans as fresh as possible and frequently, in the amount you can drink.

[0008] In regions with heavy snowfall, snow storage has long been practiced, where snow and ice collected during the winter are used to build icehouses or snowhouses, which are then used as a cooling source for storing food during the summer. For example, Non-Patent Document 1 examines the effect of snow storage on improving the taste of several foods, including coffee, cheese, flour, and vegetables.

[0009] According to Non-Patent Document 1, coffee that has been aged in a snow room has been reported to have improved flavor, such as a significantly reduced astringency and increased sweetness. Specifically, the report states that coffee that has been aged in a snow room has a reduced composition ratio of aldehydes and ketones, which have pungent or unpleasant odors, and an increased composition ratio of pyrazines, which have a sweet or fragrant aroma, and furans, which have a coffee-like aroma, which contributes to the mildness of the drink.

[0010] However, even coffee that has been aged in a snow room will still begin to deteriorate in flavor if it is removed from the snow room and stored at room temperature. Therefore, there is a need to develop roasted coffee beans that can be stored for long periods at room temperature without losing flavor, as well as a method for storing roasted coffee beans for long periods. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-300180 [Patent Document 2] Special Publication No. 2018-536408 [Non-patent literature]

[0012] [Non-Patent Document 1] Shin Kamiyama and Hideyuki Sone, University of Niigata Prefecture, "New high-value-added food storage using snow," Journal of the Japan Society of Home Economics, Vol. 72, No. 1 (2021), pp. 47-53 Summary of the Invention [Problem to be solved by the invention]

[0013] In view of the above-mentioned conventional drawbacks, the present invention is based on a novel concept and aims to provide roasted coffee beans that can be stored for a long period of time even at room temperature after roasting without losing their flavor, and a method for storing the same. [Means for solving the problem]

[0014] In view of the above object, the present inventors conducted extensive research and discovered that by storing roasted coffee beans roasted to have a predetermined texture for a long period of time in a storage container with a predetermined oxygen permeability, it is possible to obtain matured roasted coffee beans that do not deteriorate in flavor, have a clean taste, and have a reduced diacetyl content, which is a cause of health problems. This discovery led to the present invention. Specifically, the problems of the present invention can be solved by the following configuration.

[0015] The first invention is roasted coffee beans characterized by having a texture that satisfies the following (A) and (B): (A) The pore volume calculated by the nitrogen BJH method is 1.5 × 10 -3 cm 3 / g or more 3.0×10 -3 cm 3 / g or less. (B) The total volume of pores with diameters of 20 Å to 200 Å calculated by the nitrogen BJH method is 1.5 × 10 -3 cm 3 / g or more.

[0016] The second invention is roasted coffee beans characterized in that the surface color tone of the roasted coffee beans is measured with a color difference meter and the standard deviation of the L* value is within ±0.8 in the L*a*b* color system.

[0017] The third aspect of the present invention is to provide roasted coffee beans having a texture that satisfies the above-mentioned (A) and (B) at an oxygen permeability of 5000 cm 3 / m 2 ·24h · ATM or more 20000cm 3 / m 2This is a method for aging roasted coffee beans, characterized by including an aging step in which roasted coffee beans are aged at room temperature in a storage container at a temperature of 24h·atm or less.

[0018] The fourth invention is a method for aging roasted coffee beans, characterized in that in the aging step, the storage container is stored in a wooden container whose inner surface is coated with a metal layer.

[0019] A fifth aspect of the present invention is a method for aging roasted coffee beans, characterized in that in the aging step, the roasted coffee beans are aged at room temperature for at least three months or more.

[0020] The sixth invention is aged roasted coffee beans that have been roasted for at least one month or more, characterized in that the surface color tone of the aged roasted coffee beans is measured with a colorimeter in an L*a*b* color system, with a standard deviation of the L* value being within ±0.8, and the beans have a texture that satisfies the above-mentioned (A) and (B).

[0021] The seventh invention of the present invention is aged roasted coffee beans characterized in that the diacetyl content is 70 ng / g or less.

[0022] The eighth aspect of the present invention provides aged roasted coffee beans packed in a container, the container having an oxygen permeability of 5000 cm 3 / m 2 ·24h · ATM or more 20000cm 3 / m 2 The packed aged roasted coffee beans are characterized in that the temperature is 24h·atm or less, the color tone of the surface of the aged roasted coffee beans is measured with a colorimeter in an L*a*b* color system, with a standard deviation of the L* value being within ±0.8, and the aged roasted coffee beans have a texture that satisfies the above-mentioned (A) and (B).

[0023] A ninth aspect of the present invention is packed aged roasted coffee beans, characterized in that the container is a bag-shaped container made of resin and having a thickness of 20 μm or more and 200 μm or less. [Effects of the Invention]

[0024] According to the first aspect of the present invention, by roasting coffee beans so that they have a texture that satisfies the above (A) and (B), roasted coffee beans are obtained that do not deteriorate in flavor even at room temperature and can be stored for a long period of time.

[0025] According to the second invention, by keeping the standard deviation of the L* value of roasted coffee beans within ±0.8, it is possible to prevent the inclusion of beans that cause deterioration in taste.

[0026] According to the third aspect of the present invention, roasted coffee beans having a texture satisfying the above (A) and (B) can be aged at room temperature in a storage container with a predetermined oxygen permeability, thereby reducing the diacetyl content, which is a cause of health problems, and improving the flavor.

[0027] According to the fourth aspect of the present invention, a storage container containing roasted coffee beans having a texture satisfying the above (A) and (B) is stored in a wooden container whose inner surface is coated with a metal layer. The wooden container whose inner surface is coated with a metal layer has excellent heat insulation, moisture resistance, light blocking, and insect resistance, so that the freshness and flavor of the roasted coffee beans can be maintained for a long period of time.

[0028] According to the fifth aspect of the present invention, roasted coffee beans having a texture that satisfies the above (A) and (B) are aged at room temperature for at least three months or more, whereby off-flavor components are significantly reduced, further improving the taste.

[0029] According to the sixth aspect of the present invention, by keeping the standard deviation of the L* value of aged roasted coffee beans within ±0.8, it is possible to prevent the inclusion of beans that cause deterioration in taste. The inclusion of beans that do not meet the specific structural requirements set forth in the present invention is undesirable because it causes deterioration in taste, but by selecting beans to a level where the standard deviation of the L* value is within ±0.8, the beans can be stored at room temperature for at least three months after roasting, and under appropriate storage conditions, can be stored at room temperature for at least one year after roasting.

[0030] According to the seventh invention, the diacetyl content can be reduced, thereby reducing the risk of health damage caused by diacetyl.

[0031] According to the eighth aspect of the present invention, an oxygen permeability of 5000 cm 3 / m 2 ·24h · ATM or more 20000cm 3 / m 2 By packaging it in a container that can withstand 24 hours or less atm, it is possible to continue maturing without any deterioration in flavor even after the consumer has purchased it.

[0032] According to the ninth aspect of the present invention, by using a resin bag-shaped container having a thickness of 20 μm or more and 200 μm or less, it is possible to ensure sufficient strength as a storage container, and the handling properties as a product are improved. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a flowchart showing a method for producing roasted coffee beans and a method for aging roasted coffee beans. [Figure 2A] FIG. 1 is a photomicrograph (×1000) of a cross section of roasted coffee beans (compliant product) of the present invention. [Figure 2B] This is a micrograph (×1000) of a cross section of a lightly roasted coffee bean (non-compliant). [Figure 2C] This is a micrograph (1000x) of a cross section of an over-roasted roasted coffee bean (non-conforming product). [Figure 3A] FIG. 1 illustrates one embodiment of a degassing process. [Figure 3B] FIG. 1 illustrates one embodiment of the aging process. [Figure 3C] FIG. 10 shows another embodiment of the aging process. [Figure 4] FIG. 1 is a diagram showing a test bag used for measuring oxygen permeability. [Figure 5] 1 is a graph showing the measurement results of the cumulative pore volume of roasted coffee beans in Examples 1 to 3. [Figure 6]1 is a graph showing the measurement results of the cumulative pore volume of roasted coffee beans of Comparative Examples 1 to 3. [Figure 7] 1 is a graph showing the measurement results of the cumulative pore volume of roasted coffee beans of Comparative Examples 4 to 6. [Figure 8] 1 is a graph showing the measurement results of the pore size distribution of roasted coffee beans in Example 1. [Figure 9] 1 is a graph showing the measurement results of the pore size distribution of roasted coffee beans in Comparative Example 3. [Figure 10] 1 is a graph showing the measurement results of the pore size distribution of roasted coffee beans in Comparative Example 5. DETAILED DESCRIPTION OF THE INVENTION

[0034] Below, roasted coffee beans that can be stored for a long period at room temperature, a method for aging roasted coffee beans, aged roasted coffee beans, and packaged aged roasted coffee beans will be described in detail.

[0035] In this specification, "roasted coffee beans" are defined as coffee beans that have been roasted but not yet subjected to the aging process, and "aged roasted coffee beans" are defined as coffee beans that have been roasted for at least 30 days or more. Unless otherwise specified, the term "roasted coffee beans" does not include aged roasted coffee beans or roasted coffee beans in the aging process. Furthermore, when a numerical range is referred to in this specification, unless otherwise specified, the numerical range includes the upper and / or lower endpoints.

[0036] (1) Roasted coffee beans (Roasted coffee bean structure) The roasted coffee beans of the present invention are characterized by having a texture that satisfies the following (A) and (B), as calculated based on the amount of nitrogen adsorption in adsorption / desorption isotherm measurements using nitrogen as the adsorbed species. (A) The pore volume calculated by the nitrogen BJH method is 1.5 × 10 -3 cm 3 / g or more 3.0×10 -3 cm 3 / g or less. (B) The total volume of pores with diameters of 20 Å to 200 Å calculated by the nitrogen BJH method is 1.5 × 10 -3 cm 3 / g or more.

[0037] By roasting coffee beans so that they have a texture that satisfies the above (A) and (B), roasted coffee beans that can be stored for a long time without deteriorating in taste even at room temperature can be obtained. The reason why the roasted coffee beans of the present invention can be stored for a long time at room temperature is not clear, but it is thought that the above-mentioned texture suppresses the deterioration of the oil contained in the roasted coffee beans.

[0038] Furthermore, by aging the roasted coffee beans of the present invention in a storage container with a predetermined oxygen permeability, the resulting aged roasted coffee beans can have a reduced diacetyl content, which is a cause of health hazards.Furthermore, the bitterness is mellowed, the sweetness is increased, and the aged roasted coffee beans have a clean taste.

[0039] Furthermore, it is preferable that the roasted coffee beans of the present invention satisfy the following requirement (C) in addition to the requirements (A) and (B) above. (C) The specific surface area calculated by the nitrogen BET method is 1.5 m 2 / g or more 2.5m 2 / g or less.

[0040] (color tone) The roasted coffee beans of the present invention have an L* value of the bean surface color tone in the L*a*b* color system measured with a color difference meter, which average value is between 15 and 27. In this specification, the average value and standard deviation of the L*a*b* color system are values ​​(n=20) calculated from the L*a*b* values ​​of 20 beans randomly selected from the roasted coffee beans, measured with a spectrophotometer (SCI method).

[0041] The roasted coffee beans of the present invention preferably have as little color variation as possible from bean to bean. The standard deviation of the L* value of the roasted coffee beans of the present invention is within ±0.8, preferably within ±0.7, more preferably within ±0.65, and even more preferably within ±0.5. The standard deviation of the a* value is within ±0.8, preferably within ±0.7, more preferably within ±0.65, and even more preferably within ±0.5. The standard deviation of the b* value is within ±0.9, preferably within ±0.8, more preferably within ±0.7, and even more preferably within ±0.6.

[0042] Furthermore, the color difference ΔE*(ab) of the roasted coffee beans of the present invention is preferably 3.0 or less, more preferably 2.0 or less, even more preferably 1.0 or less, and particularly preferably 0.8 or less.

[0043] (water activity) The roasted coffee beans of the present invention are thoroughly roasted to the core of the beans, and preferably have a water activity value of 0.05 Aw or more and 5.0 Aw or less, more preferably 1.5 Aw or more and 3.5 Aw or less.

[0044] If the water activity value exceeds 5.0Aw, the freshness of the roasted coffee beans will be easily lost and they will tend to have an unpleasant sour taste. In addition, mold may grow, and there will be hygiene risks such as spoilage during the aging process.

[0045] If the water activity is less than 0.05Aw, the coffee is over-roasted, which can lead to a strong, stinging bitterness in the mouth. Furthermore, during the aging process, drying can cause changes in the pore morphology of the beans, which can lead to oxidation of the oils contained in the beans and a deterioration in flavor.

[0046] (2) Method for manufacturing roasted coffee beans Next, the method for producing roasted coffee beans of the present invention will be described. Figure 1 shows a flowchart of the method for producing roasted coffee beans of the present invention and the method for aging the obtained roasted coffee beans.

[0047] The method for producing roasted coffee beans of the present invention includes a first picking step (step S11) of removing defective beans from raw coffee beans as raw material and homogenizing the raw beans, a roasting step (step S12) of roasting the raw beans to change the bean's texture and prepare roasted coffee beans with a predetermined texture, a cooling step (step S13) of cooling the roasted coffee beans at a high temperature, a second picking step (step S14) of removing beans that do not have the predetermined texture from the roasted coffee beans, and a degassing step (step S15) of releasing carbon dioxide gas generated from the freshly roasted coffee beans.

[0048] There is no particular restriction on the order of the second picking process (step S14) and the degassing process (step S15), and the second picking process (step S14) may be performed after the degassing process (step S15), or the second picking process (step S14) may be performed during the degassing process (step S15).

[0049] (Coffee beans as raw material) The coffee beans used as the raw material are not particularly limited, and commonly available green coffee beans can be used. For example, the variety of coffee beans (Arabica, Robusta, Liberica, etc.), place of production, refining method (natural, washed, etc.), storage period, grade, etc. are not particularly limited, and can be selected appropriately by a person skilled in the art.

[0050] It is preferable that the raw coffee beans be homogeneous. That is, it is preferable to use a single type of coffee, rather than blending multiple different types of raw coffee beans. It is also preferable that the raw coffee beans be uniform in color. Beans with different colors have different moisture contents, which can cause uneven roasting. It is also preferable that the raw coffee beans be uniform in size. Beans with different sizes are roasted at different times, which can cause uneven roasting.

[0051] (First picking process) If the raw coffee beans contain defective beans, this will cause uneven roasting, so in the first picking step, defective beans (worm-eaten beans, immature beans, cracked beans, beans of different colors, beans of different sizes, etc.) contained in the raw coffee beans are removed by hand picking or the like (step S11). Note that the first picking step is not essential, and for example, if high-quality raw beans with almost no defective beans are used, the first picking step may be omitted.

[0052] (Roasting process) Next, in the roasting process, the green coffee beans are roasted (step S12). Coffee bean roasting methods can be roughly classified into three types: direct fire, hot air, and semi-hot air. The direct fire method is a method in which a perforated drum is used to directly apply fire to the coffee beans, and the hot air method is a method in which hot air is blown into a drum containing the coffee beans, and the roasting method is performed by blowing hot air into the drum. The semi-hot air method is an intermediate method between the direct fire and hot air methods, and is a method in which heat is directly applied from the outside of a drum without holes. Furthermore, known heat sources such as electric, charcoal, gas, and steam can be used as heat sources for these roasting methods. In the present invention, any of the roasting methods may be used, but it is preferable to roast the coffee beans uniformly and without unevenness.

[0053] The amount of coffee beans to be roasted at one time can be set appropriately depending on the size of the roasting equipment, the required amount of product (roasted coffee beans), etc. The heating temperature is generally about 140°C to 230°C, but is not limited to this.

[0054] When coffee beans are heated in the roasting process, the moisture contained in the coffee beans evaporates and is lost, resulting in a roasted coffee bean weight that is approximately 20% lighter than that of raw beans. The roasted coffee beans of the present invention are roasted thoroughly to the core of the beans, and preferably have a water activity value of 0.05 Aw or more and 5.0 Aw or less.

[0055] As the roasting process progresses, the voids within the beans gradually expand, forming a porous structure. This releases the inherent coffee aroma and allows oils to seep out. Figures 2A to 2C are micrographs of cross sections of roasted coffee beans. Figure 2A shows roasted coffee beans of the present invention (compliant), Figure 2B shows lightly roasted beans (non-compliant), and Figure 2C shows over-roasted beans (non-compliant).

[0056] In the roasted coffee beans of the present invention (compliant product) shown in Figure 2A, the moisture contained in the beans has almost completely evaporated, the cross-sectional shape of the pores in the beans is close to perfect circle, and the aspect ratio of the pores is close to 1:1. It has been found that beans roasted to the specified texture state defined by the present invention maximize the coffee flavor and tend to show minimal change in morphology over time during long-term storage. While the reason why the roasted coffee beans of the present invention can be stored for long periods at room temperature is unclear, it is presumed that carbon dioxide is stably retained in the tiny pores of the beans for long periods, and that this structure inhibits the deterioration of the oils contained in the roasted coffee beans.

[0057] In contrast, in the case of light roasts, the cavity of the coffee bean has not yet fully expanded, as shown in Figure 2B. When the beans are lightly roasted, the moisture remaining inside the beans shortens the peak flavor (the period during which they can be enjoyed). In addition, with light roasts, the amount of carbon dioxide produced is small, so the oils contained in the roasted coffee beans are more likely to oxidize in the air, which is thought to be a factor in the deterioration of flavor.

[0058] On the other hand, in the case of over-roasting, the moisture has completely evaporated, resulting in roasted coffee beans with roughly the same roast weight and moisture content as roasted coffee beans (compliant) of the present invention. However, as shown in Figure 2C, the cross-section of the pores in the coffee beans becomes slightly diamond-shaped, and the volume (area) of the beans is slightly reduced compared to the compliant beans. When over-roasted beans are stored for a long period of time, fine cracks develop on the surface. This presumably releases aroma components and carbon dioxide from the pores of the coffee beans, making the oils contained in the roasted coffee beans more susceptible to air oxidation.

[0059] The conditions for roasting coffee beans to the specified texture state defined in the present invention vary depending on the state of the coffee beans to be roasted (hardness, moisture content, size) and the type of roaster, so the roasting conditions of heat power and air volume are set appropriately.

[0060] During the roasting process, the time that the roasted coffee beans maintain the specified texture state defined by the present invention is extremely short, typically less than 3 seconds, with the optimal timing being approximately 1 second. This timing is determined, and the roasted coffee beans are removed from the roasting chamber to the outside. If the roasted coffee beans are removed from the roasting chamber too early, the beans will not expand sufficiently and will not achieve the specified texture structure defined by the present invention. On the other hand, if the beans are removed from the roasting chamber too late, they will be over-roasted, resulting in roasted coffee beans with a structure different from the specified texture structure defined by the present invention.

[0061] (cooling process) In the cooling process, the roasted coffee beans are quickly cooled to room temperature to stop the roasting process (Step S13). The beans in the roasting chamber are at a high temperature, so the roasted coffee beans are quickly removed from the roasting chamber into a container such as a bowl or tray to dissipate heat.

[0062] (Second picking process) The roasted coffee beans of the present invention preferably have minimal roasting unevenness. In the second picking step, beans that do not meet the requirements for the predetermined texture structure defined by the present invention are removed by hand picking or the like (step S14). If beans that do not meet the requirements for the predetermined texture structure defined by the present invention are mixed into the roasted coffee beans of the present invention, this is undesirable because it can cause a deterioration in taste.

[0063] In the second picking step, the L* value of the L*a*b* color system measured with a color difference meter can be used as one of the indices for determining whether or not the beans satisfy the above (A) and (B). First, multiple beans are selected from the roasted coffee beans, the state of the texture of each bean is confirmed, and the range of L* values ​​for roasted coffee beans having the specified texture defined in the present invention is identified and set as the bean sorting standard. Then, beans that do not fall within the L* value range for roasted coffee beans having the specified texture defined in the present invention are removed from the roasted coffee beans by hand picking or the like, thereby minimizing variation in roast level (standard deviation of L* values) as much as possible.

[0064] In the second picking step, in addition to the L* value, the a* value and the b* value may also be used to determine whether or not the beans satisfy the above (A) and (B). That is, multiple beans are selected from the roasted coffee beans, the state of the texture of each bean is confirmed, and the L* value range, a* value range, and b* value range of roasted coffee beans having the specified texture defined in the present invention are identified. Beans that do not satisfy one or more of the requirements of the L* value range, a* value range, and b* value range are then removed by hand picking or the like, thereby minimizing variation in roast level.

[0065] It goes without saying that a person skilled in the art can implement the present invention by substituting other color indices (such as Agtron values) in the above description.

[0066] (Gas removal process) Roasted coffee beans immediately after roasting contain a large amount of carbon dioxide, so they are degassed by leaving them unsealed in a well-ventilated place at room temperature (step S15). The release of carbon dioxide from the roasted coffee beans peaks 1 to 4 days after roasting, after which the gas release slows down and the flavor settles. The degassing period is between 1 day and 1 week, with 1 to 3 days being preferable.

[0067] The degassing step is preferably carried out at room temperature. If the beans are stored at a low temperature during the degassing step, condensation will occur and the beans will absorb moisture, which is not desirable.

[0068] The degassing of the roasted coffee beans is preferably carried out in a container having an opening. For example, the degassing of the roasted coffee beans may be carried out in the same bowl or the like used to cool the roasted coffee beans in the cooling step.

[0069] Alternatively, as shown in FIG. 3A, sufficiently cooled roasted coffee beans 20 may be transferred to a bag-shaped storage container 10 used in the aging process, and degassing may be performed with the mouth of the bag-shaped storage container 10 open.

[0070] The roasted coffee beans of the present invention thus obtained are subjected to the aging step (step S21) described below to produce aged roasted coffee beans of the present invention.

[0071] Needless to say, the roasted coffee beans of the present invention may be consumed without undergoing the aging step (step S21). That is, the obtained roasted coffee beans of the present invention may be ground as is (step S16) and extracted with water (step S17), and the resulting coffee extract (drip coffee, French press coffee, etc.) may be served as a beverage.

[0072] (3) Aging method of roasted coffee beans Next, the method for aging roasted coffee beans of the present invention will be described. After the degassing step, the obtained roasted coffee beans of the present invention are stored in a sealable storage container and aged. By aging the roasted coffee beans of the present invention, the flavor is improved and the diacetyl content, which causes health hazards, can be reduced.

[0073] In the aging process, the roasted coffee beans of the present invention are aged in an atmosphere having an oxygen permeability of 5000 cm 3 / m 2 ·24h · ATM or more 20000cm 3 / m 2 The roasted coffee beans are matured by storing them for a long period of time in a storage container at a temperature of 24h·atm or less (step S21).

[0074] Roasted coffee beans are aged in the bean state. Grinding them into powder increases the surface area compared to the bean state, making them more susceptible to oxidation and resulting in the loss of much of the carbon dioxide and aroma, and is therefore not suitable for the aging method of the present invention.

[0075] One embodiment of the aging process is shown in Figure 3B. In the example of Figure 3B, a commercially available garbage bag made of low-density polyethylene or the like is used as storage container 10, roasted coffee beans 20 are placed in storage container 10, and the opening of storage container 10 is tied to seal.

[0076] (Aging period) The aging period is at least 3 weeks, preferably 3 months, more preferably 6 months, and even more preferably 1 year. It has been confirmed that some sakes can be enjoyed even after 2.5 years or more if aged under appropriate conditions.

[0077] During the aging process, the roasted coffee beans are stored in a sealed storage container with a predetermined oxygen permeability. However, this does not prohibit opening the sealed storage container during the aging process. As shown in Figure 3A, storage container 10 containing roasted coffee beans 20 may be temporarily opened and served for drinking during the aging process, allowing one to enjoy the changes in the coffee's taste over time as it ages.

[0078] In addition, to hasten the aging process, the storage container containing the roasted coffee beans may be temporarily opened during the aging process, and the roasted coffee beans may be left unsealed for about a day.

[0079] (storage container) The storage containers used in the aging process have an oxygen permeability of 5000 cm 3 / m 2 ·24h · ATM or more 20000cm 3 / m 2 Storage containers with a temperature of 24h or less are recommended. Storage containers with high oxygen permeability tend to accelerate the ripening of roasted coffee beans, so if you want to speed up the ripening process, choose a container with high oxygen permeability and set the best time to drink it.

[0080] The oxygen permeability of the storage container is 5000 cm 3 / m 2 If the oxygen permeability is less than 24h atm, the diacetyl content, which can cause health problems, will not be reduced sufficiently, which is undesirable. 3 / m 2 Storing it for longer than 24h atm is not recommended as it can cause the coffee to lose its aromatic components.

[0081] The storage container used in the aging process is not particularly limited as long as it has a predetermined oxygen permeability and sufficient strength. For example, it is preferable to use a storage container made of a resin film such as polyethylene, polypropylene, or polyvinyl chloride, and particularly a storage container made of low-density polyethylene (LDPE) film. The thickness of the resin film is preferably 20 μm or more and 200 μm or less.

[0082] The shape of the storage container used in the aging step is not particularly limited, and for example, a bag-shaped container such as a commercially available garbage bag or a food storage bag with an openable zipper structure can be used.

[0083] The storage container used in the aging process may be made of a light-blocking material, such as a commercially available black garbage bag, to protect the roasted coffee beans from external light during the aging process.

[0084] Conventional roasted coffee beans deteriorate easily, and if stored in an oxygen-permeable storage container at room temperature, the taste will begin to change after about two weeks. This is why they must be stored in aluminum-coated bags or cans.

[0085] In contrast, the roasted coffee beans of the present invention have a specific texture, so the oils contained in the beans are less likely to deteriorate, and they can be stored for long periods at room temperature even in oxygen-permeable storage containers.

[0086] (Storage location) During the aging process, the storage container containing the roasted coffee beans of the present invention can be stored at room temperature. A suitable storage location is indoors, away from direct sunlight, and where the temperature and humidity are stable.

[0087] Room temperature is 5 to 40° C., preferably 10 to 30° C., and the ideal storage temperature is 15 to 20° C. If the temperature is too high, oxidation will progress and the flavor will be impaired, so it is preferable to store it in as cool a place as possible.

[0088] The preferred humidity for storage is 20-80%, more preferably 40-70%, and most preferably 50-60%. It is important to maintain an appropriate humidity level, as too high a humidity level can cause mold, and too low a humidity level can dry out the beans.

[0089] The water activity value of roasted coffee beans during aging is preferably 0.05 Aw or more and 5.0 Aw or less. A water activity value above 5.0 Aw poses hygiene risks such as spoilage, while a water activity value below 0.05 Aw is undesirable because drying can cause morphological changes in the pores of the beans. The water activity value of roasted coffee beans during aging is more preferably 2.0 Aw or more and 5.0 Aw or less.

[0090] Furthermore, since light can cause deterioration of roasted coffee beans, it is ideal to store the storage container containing the roasted coffee beans of the present invention in a light-blocking location.

[0091] In one preferred embodiment of the present invention, as shown in FIG. 3C, a storage container 10 containing roasted coffee beans 20 is stored in a so-called tea chest 30. The tea chest 30 is a housing 31 with a lid 32, made of a board material such as cedar. The inside of the housing 31 and the inside of the lid 32 are lined with metal layers 31A, 32A, such as tin. While tea chests are originally used to store tea, their excellent insulation, moisture-proofing, light-blocking, and insect-repellent properties make them ideal for storing storage containers containing roasted coffee beans. Of course, the storage location is not limited to a tea chest; any storage space with similar functions as a tea chest may be used. For example, a storage container containing roasted coffee beans may be stored in a wooden container whose inner surface is coated with a metal layer.

[0092] As such, the storage location of storage containers containing roasted coffee beans is important for maintaining the quality of the beans, and storing them in a place with properly controlled temperature and humidity will help maintain the freshness and flavor of the roasted coffee beans for a long period of time.

[0093] (4) Aged roasted coffee beans The aged roasted coffee beans obtained through the above-mentioned aging process have a reduced diacetyl content, which is a cause of health problems, and show almost no increase in acidity even after long-term storage. Sensory evaluation also shows that the beans are free of the unpleasant acidity associated with oil deterioration, have a mellower taste, are refreshing to drink, and tend to have an increased sweetness.

[0094] (Structure of matured roasted coffee beans) The aged roasted coffee beans of the present invention have a texture that satisfies the requirements (A) and (B) described above.

[0095] In other words, one of the characteristics of the aged roasted coffee beans of the present invention is that they undergo little morphological change due to long-term storage, and compared to roasted coffee beans before aging, there is almost no change in the specific surface area and pore volume, and they maintain values ​​that are almost the same as those of roasted coffee beans before aging.

[0096] The aged roasted coffee beans of the present invention have a pore volume value calculated by the nitrogen BJH method that is in the range of 0.7 to 1.5 times, and preferably 0.9 to 1.2 times, that of roasted coffee beans before aging.

[0097] (Diacetyl content) One of the features of the aged roasted coffee beans of the present invention is that the diacetyl content is reduced compared to roasted coffee beans before aging by storing them for a long period of time in a storage container with a specified oxygen permeability.

[0098] Diacetyl is a compound considered a health hazard in the coffee industry and can cause serious and irreversible lung disease. Diacetyl vapor is also produced as a by-product during roasting and crushing of coffee beans, and even when diacetyl is present at low concentrations in coffee beans, exposure to the vapor can exceed safe workplace exposure limits (WELS). The aging method of the present invention enables the reduction of diacetyl content in roasted coffee beans through a simple storage method without the need for chemical or other treatments, making it a simple and excellent method for removing diacetyl.

[0099] In the roasted coffee bean aging method of the present invention, the longer the aging period, the lower the diacetyl content. In conventional storage containers with virtually zero oxygen permeability, such as aluminum-coated bags or cans, the diacetyl contained in the roasted coffee beans is trapped within the storage container, tending to increase the diacetyl content. However, in the storage containers used in the present invention, which have a specified oxygen permeability, diacetyl is easily released outside the storage container, which is presumably what contributes to the reduction in the content of off-flavor components.

[0100] According to the method for aging roasted coffee beans of the present invention, the diacetyl content can be reduced to 0.8 times or less, preferably 0.5 times or less, more preferably 0.3 times or less, even more preferably 0.2 times or less, and particularly preferably 0.1 times or less, compared to roasted coffee beans before aging.

[0101] The aged roasted coffee beans of the present invention have a diacetyl content of 70 ng / g or less, preferably 60 ng / g or less, more preferably 50 ng / g or less, and even more preferably 30 ng / g or less.

[0102] (color tone) As the aging period increases, the brightness of the aged roasted coffee beans of the present invention tends to decrease slightly, but color variation between beans remains small and is almost unchanged compared to roasted coffee beans before aging.

[0103] The aged roasted coffee beans of the present invention have an average L* value of the color tone of the bean surface in the L*a*b* color system measured with a color difference meter of 15 or more and 27 or less.

[0104] In the L*a*b* color system measured with a colorimeter, the standard deviation of the L* value of the aged roasted coffee beans of the present invention is within ±0.8, preferably within ±0.7, more preferably within ±0.65, and even more preferably within ±0.5. The standard deviation of the a* value is within ±0.8, preferably within ±0.7, more preferably within ±0.65, and even more preferably within ±0.5. The standard deviation of the b* value is within ±0.9, preferably within ±0.8, more preferably within ±0.7, and even more preferably within ±0.6.

[0105] Furthermore, the color difference ΔE*(ab) of the aged roasted coffee beans of the present invention is 3.0 or less, preferably 2.0 or less, more preferably 1.0 or less, and even more preferably 0.8 or less.

[0106] (Packing of aged roasted coffee beans) The aged roasted coffee beans of the present invention can be packed in a packaging material and provided to consumers.

[0107] A preferred packaging material is a container having an oxygen permeability similar to that of the storage container used in the aging process. 3 / m 2 ·24h · ATM or more 20000cm 3 / m 2 Containers with a temperature of 24h·atm or less can be used as packaging materials. The packaging material is preferably a bag-shaped container, and preferably has an openable and closable zipper structure. By packing the aged roasted coffee beans of the present invention in a bag-shaped container with a predetermined oxygen permeability, aging continues even after the consumer purchases the beans, allowing the consumer to enjoy the changes in the coffee's flavor over time due to aging.

[0108] Another preferred sales method is to provide consumers with aged roasted coffee beans packed in a bag-shaped container with a specified oxygen permeability, which is then further housed in a container such as a tea box.

[0109] The above packaging materials are merely examples, and do not preclude the aged roasted coffee beans of the present invention from being packaged and provided in conventional coffee packaging materials such as cans, bottles, and aluminum-coated bags.

[0110] (extraction) The aged roasted coffee beans of the present invention are ground into powder just before consumption (step S22) and extracted with water (step S23). [Example]

[0111] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The analytical results in the following examples were measured at the request of the Gunma Prefectural Industrial Technology Center.

[0112] (1) Adjustment of roasted coffee beans (Moccasin compatible) Defective beans were removed by hand-picking from 10 kg of raw beans (mocha, produced in Ethiopia), and the beans were roasted using a direct-fire roaster (manufactured by Fuji Royal Co., Ltd.). After the roasted coffee beans were cooled to room temperature, beans that did not meet the requirements for the specified texture defined in the present invention were removed by hand-picking from the roasted coffee beans, thereby preparing the roasted coffee beans of the present invention (mocha-compliant product).

[0113] (Roasted coffee beans from other companies) We prepared six types of roasted coffee beans (mocha) from another company that were roasted on a similar date to the mocha-compatible products described above and had a relatively similar roasting level (color).

[0114] (Kenya compliant) Defective beans were removed by hand-picking from 10 kg of raw beans (Kenya) as raw material, and the beans were roasted using a direct-fire roaster (manufactured by Fuji Royal Co., Ltd.). After the roasted coffee beans were cooled to room temperature, beans that did not meet the specific texture requirements set forth in the present invention were removed by hand-picking from the roasted coffee beans to prepare roasted coffee beans (Kenya-compliant) of the present invention.

[0115] (Kenyan light roast) 10 kg of raw beans (Kenya) were hand-picked to remove any defective beans, and then roasted slightly lighter than the Kenyan standard using a semi-direct fire roaster (Fuji Royal Co., Ltd.). After cooling the roasted coffee beans to room temperature, beans with different color tones were hand-picked to remove them, and the roasted coffee beans (Kenya light roast) were prepared.

[0116] (2) Aging conditions for roasted coffee beans The roasted coffee beans described above were analyzed at 0, 1, and 3 months after storage under the various conditions shown in Table 1. Note that Example 4 (Kenyan-compliant product) and Comparative Example 7 (Kenyan light roast) were analyzed at 0 and 6 months.

[0117] [Table 1]

[0118] (storage container) In Examples 1, 3, and 4 and Comparative Example 7, roasted coffee beans were stored in commercially available 45 L black garbage bags (made of low-density polyethylene (LDPE), 60 μm thick) and aged.

[0119] In Example 2, the roasted coffee beans were stored in a commercially available aluminum vapor-deposited bag (manufactured by Seisan Nippon Co., Ltd., "Lamizip" flat bag, thickness 114 μm) and the roasted coffee beans were aged.

[0120] In addition, for Comparative Examples 1 to 6, the roasted coffee beans were stored and aged in the aluminum vapor-deposited bags in which they were packaged when purchased from each company.

[0121] The oxygen permeability of the storage container used in the aging process was measured according to the following procedure.

[0122] First, the storage container was cut to a size of 155 x 265 mm, and the obtained plastic film was overlapped and heat-sealed around the periphery. After that, a cock was attached to prepare the test bag shown in Figure 4.

[0123] After removing the air from the test bag through a valved cock using a vacuum pump, 1 L of nitrogen was introduced into the test bag from a high-pressure nitrogen cylinder (G1 grade).

[0124] The test bag was allowed to stand at room temperature, and then the oxygen composition inside the test bag was measured using a thermal conductivity detector type gas chromatograph under the following conditions: Equipment: Gas chromatograph (Shimadzu Corporation, GC2014) Sample volume: 0.5mL Carrier gas: Argon Separation column: SHINCARBON ST (6.0 m x 3.00 mm ID, manufactured by Shinwa Chemical Co., Ltd.) Column temperature: 60 °C (14 min) → 20 °C / min → 180 °C (5 min) Detector: Thermal Conductivity Detector (TCD) Detector temperature: 150°C, detector current: 70mA

[0125] The amount of gas in the test bag was quantified by the water displacement method, and the product of the oxygen composition and the amount of gas in the test bag was taken as the oxygen permeation rate. The plot of the change in oxygen permeation rate over time (vertical axis: oxygen permeation rate (cm)) was then made. 3 ), horizontal axis: time (h)) 3 / h·atm), the outer surface area of ​​the test bag (m 2 ) and calculate the oxygen permeability (cm 3 / m 2 24h atm) was calculated.

[0126] TIFF0007822657000003.tif17122

[0127] (tea box) The tea box used was a commercially available 30kg size (long side 59cm x short side 40cm x height 47cm) tea box made of domestic cedar wood and lined with galvanized iron.

[0128] (3) Water activity The results of the water activity of the roasted coffee beans are shown in Table 2. In Example 2 and Comparative Examples 1 to 6, which used aluminum-deposited bags, the water activity values ​​were low, around 0.1 Aw, whereas in Example 1 (LDPE bag + tea box) and Example 3 (LDPE bag), which were stored in commercially available LDPE bags, the water activity values ​​were around 0.4 Aw. This is thought to be due to the adsorption of moisture from the air. However, because both had a water activity value of 0.5 Aw or less, which is considered to be the level at which microorganisms do not grow, the possibility of mold growth was extremely low, and storage in a storage container with the specified oxygen permeability is thought to be unlikely to result in deterioration of hygiene, such as spoilage. Furthermore, because the storage period was from the first week of August to the first week of November, a time when humidity and temperature are high and water activity values ​​are likely to be high, it is estimated that the water activity value would be maintained at 0.5 Aw or less throughout the year, even when stored in a storage container with the specified oxygen permeability.

[0129] [Table 2]

[0130] (4) Color tone L*a*b* and L(Hunter) were measured under the following conditions using a spectrophotometer (Spectrophotometer SD7000, manufactured by Nippon Denshoku Industries Co., Ltd.). L*a*b* measurements were performed on 20 beans (n=20) randomly selected from each roasted coffee bean, and the average, standard deviation, maximum, and minimum values ​​were calculated. Note that the SCE (specular reflection excluded) method of measurement evaluates color visually, while the SCI (specular reflection included) method evaluates the color of the material itself. Measurement method: Reflection method (SCE, SCI) Measurement diameter: φ6.4mm Light source: D65 (with UV) Field of view: 10

[0131] [Table 3]

[0132] Table 3 shows that the roasted coffee beans of the present invention (Examples 1 and 4) had a smaller standard deviation than beans from other companies, indicating that they were roasted more uniformly with less variation in roast level. Furthermore, ΔE*(ab) of Example 1 (3 months) based on Example 1 (0 months) was 0.67 (SCE) and 0.64 (SCI), indicating that there was no significant difference in color even after 3 months.

[0133] (5) Taste For each sample, 45g of freshly ground coffee beans were infused in 350g of hot water in a 400ml glass French press for 4 minutes, and the resulting solution was extracted.

[0134] (Evaluation using a taste sensor) Each sample was analyzed using a taste recognition device (TS-5000Z, manufactured by Intelligent Sensor Technology Co., Ltd.) The standard sample used for the calibration process was a solution prepared by dissolving 1.2 g of Nescafé Gold Blend (manufactured by Nestle Japan Co., Ltd.) in 140 g of boiling water. The evaluation items were sourness, bitterness, astringency, umami, saltiness, bitterness, astringency, and umami richness. Using various sensors (AAE, CT0, CA0, C00, AE1), sourness, bitterness, astringency, umami, saltiness, bitterness, astringency, and umami richness were measured according to the manual.

[0135] When evaluating each taste using a taste sensor, a difference of 1 is considered to be noticeable to the average person, while a difference of around 0.5 is considered to be detectable at the quality control level. Furthermore, when evaluating coffee, saltiness is expressed as a coffee flavor, not a salty taste caused by sodium chloride or other substances. Table 4 shows the interpolated difference values ​​measured by the taste sensor, with a "Moccha-compliant product, aged 0 months" being used as the reference value of 0.

[0136] [Table 4]

[0137] From the results in Table 4, it can be inferred that the coffee beans of Comparative Examples 1, 2, and 4 to 6 had high acidity values ​​and low bitterness, off-flavors, and sweetness values, and therefore the roast level of each sample was lighter than that of the mocha-compliant product. On the other hand, it can be seen that Comparative Example 3 was closer to a darker roast than the mocha-compliant product. It is noteworthy that when comparing the "mocha-compliant product (0 months)" and the "Kenya-compliant product (stored for 6 months)," the difference between the values ​​for all tastes was less than "0.5," indicating that the aging method of the present invention causes almost no deterioration or change in taste due to long-term storage.

[0138] Next, comparing the changes over time up to three months for Example 1 (LDPE bag + tea box), Example 2 (aluminum vapor-deposited bag), and Example 3 (LDPE bag), no difference in taste was observed between the storage methods at one and three months. At three months, there was no change in taste that the average person would notice, regardless of the storage method, and even people familiar with coffee would only notice a slight acidity or coffee flavor, indicating that mocha-compatible coffee can be preserved without any change when stored in an oxygen-permeable storage container, compared to when stored in a commonly available aluminum vapor-deposited bag.

[0139] (sensory evaluation) Next, three panelists evaluated each extract obtained from the roasted coffee beans after three months of storage to determine whether it was drinkable or not, from the perspectives of sourness and stale odor. The sourness and stale odor were judged according to the following evaluation criteria. acidity 〇 It has a moderate acidity and is delicious as coffee. △ It can be drunk as coffee, but the sourness lingers in the mouth and is difficult to drink. × It is not tasty as coffee. It has a strong, sour taste like putrid coffee. Deterioration odor 〇 There is absolutely no smell of deterioration. △ There is a slight smell of deterioration. × A strong smell of deterioration is felt.

[0140] A sensory evaluation was conducted by three panelists, and all panelists rated Comparative Examples 1 to 6 as "x" for sourness and deterioration odor. This is thought to be because the expiration dates set by each company for Comparative Examples 1 to 6 had passed. After three months of storage, Comparative Examples 1 to 6 had a strong sourness and a deterioration odor like old oil, making them unsuitable for drinking. On the other hand, after three months of storage, Examples 1 to 3 (Moka-compliant products) and Example 4 (Kenya-compliant product) were all rated as "good" for sourness and deterioration odor. Specifically, the evaluations indicated that the sourness and bitterness were well balanced, the aftertaste of the sourness and bitterness was short, and the taste was mellow and refreshing.

[0141] (6) Odor For the analytical sample, 2-3 g of the specimen was crushed into powder using a Multi-Bead Shocker (Yasui Kikai Co., Ltd.), and 5.0 mg of the crushed material was precisely sealed in a dedicated vial.

[0142] The analysis was performed using a triple quadrupole gas chromatograph mass spectrometer (GCMS-TQ8050 NX / AOC-6000 Plus [Shimadzu Corporation]) by solid-phase microextraction (SPME). Semi-quantitative analysis of off-flavor components using the GCMSMS off-flavor analysis system was performed under the following conditions. Solid-phase microextraction conditions Fiber: Smart SPME fiber (DVD / Carbon WR / PDMS, 80 μm) Heating temperature: 80℃ Extraction time: 30 minutes Gas chromatographic conditions Separation column: InertCap Pure-Wax [30 m x 0.25 mm ID, 0.25 μm, manufactured by GL Sciences] Heating conditions: 50°C (5 min) - 10°C / min - 250°C (10 min) Mass spectrometry conditions Ion source temperature: 200℃ Interface temperature: 250℃ MRM(Multiple Reaction Monitoring) Measurement mass (precursor / product ion): Complies with the odor analysis system requirements Semi-quantitative conditions : Complies with odor analysis system requirements

[0143] Furthermore, under the same analytical conditions as above, when peaks with different area values ​​were observed in the total ion current (TIC) chromatograms obtained by simultaneous scan analysis, with the zeroth month as the reference point for each sample, the peaks were subjected to a library search using NIST or other libraries within the measurement mass range of m / z = 45-500 to identify the compounds. The results of the off-flavor analysis by GCMSMS are shown in Tables 5 to 7.

[0144] [Table 5]

[0145] [Table 6]

[0146] [Table 7]

[0147] Tables 5 to 7 show that the overall tendency for samples is that the total content of offensive odor components increases after one month compared to zero months, and remains the same or has decreased at three months. When samples were stored in aluminum-coated bags, many of the bags had swelled significantly with carbon dioxide at one month, which is thought to be why the volatile components also increased at one month. Furthermore, it is thought that these volatile components decreased at three months due to evaporation and decomposition.

[0148] Focusing on differences in storage methods, the total content of off-flavor components differed after one month, with Example 1 (LDPE bag + brown box) > Example 2 (aluminum-coated bag) ≒ Example 3 (LDPE bag). However, after three months, the order was Example 2 (aluminum-coated bag) > Example 1 (LDPE bag + brown box) > Example 3 (LDPE bag). While the details are unclear, it is speculated that the air permeability of the LDPE bag causes the off-flavor components to increase more quickly than the aluminum-coated bag, and then the content decreases more quickly than in the aluminum-coated bag due to volatilization or decomposition. Furthermore, Example 1 (LDPE bag + brown box) and Example 3 (LDPE bag) had lower total content of off-flavor components than Example 2 (aluminum-coated bag). In particular, the content of nitrogen-containing heterocyclic compounds such as pyrazine and 5-methyl-2-furfural decreased. The content of these compounds did not decrease over time when other samples were stored with aluminum-coated bag. This is a characteristic change observed when stored in an LDPE bag, i.e., an oxygen-permeable container.

[0149] With regard to aldehydes, which are considered to be indicators of bean deterioration, most components in each sample showed an increase compared to month 0, but diacetyl was the only component that decreased in Example 1 (LDPE bag + tea box) and Example 3 (LDPE bag). Table 8 shows the results of diacetyl analysis by GCMSMS.

[0150] [Table 8]

[0151] Diacetyl is a compound for which the UK Health and Safety Executive (HSE) issued a safety alert in 2023. In Example 1, the diacetyl content decreased to less than 0.5 times after three months, and in Example 3, the diacetyl content decreased to less than 0.2 times after three months, demonstrating that the coffee bean aging method of the present invention is also an excellent method for removing diacetyl.

[0152] (6) Electron microscope observation Electron microscopic observations showed that the Kenya-compliant product showed no difference in the inner wall change over time, even after six months from roasting, compared to the product at zero months after roasting. Furthermore, the Mocha-compliant product showed no difference in the inner wall change over time, even after three months from roasting, compared to the product at zero months after roasting. Meanwhile, in Comparative Examples 1, 2, and 4 to 6, the occurrence of fine cracks on the surface of the beans was confirmed one month after roasting.

[0153] During roasting, coffee beans form voids, trapping carbon dioxide within them. Lighter roasts produce fewer voids, but also produce less carbon dioxide, making the oils more susceptible to air oxidation. Darker roasts, on the other hand, produce more carbon dioxide, but with longer storage periods, tiny cracks form on the surface, releasing the carbon dioxide from the voids and making the beans more susceptible to air oxidation. For this reason, roasted coffee beans that are less susceptible to air oxidation must produce a sufficient amount of carbon dioxide and show minimal change in morphology over time.

[0154] (7) Cumulative pore volume The time-dependent change in cumulative pore volume was investigated using the gas adsorption method. Using a multi-analyte gas adsorption analyzer (Anton Paar, Autosorb-iQ2-XR-VP), adsorption isotherms were measured at liquid nitrogen temperature using nitrogen as the adsorbed gas. The pore volume was calculated from the resulting adsorption isotherms using the BJH method. The relative pressure range was from 0 to 1, and the nitrogen adsorption volume was measured at intervals of 0.025 relative pressure. The cumulative pore volume measurement results are shown in Figures 5 to 10 and Tables 9 and 10.

[0155] [Table 9]

[0156] [Table 10]

[0157] The cumulative pore volume at 0 months was the largest for the mocha-compatible products (Examples 1 to 3), which suggests that the surface area in contact with air is larger than that of the other samples. However, when the cumulative pore volume at 0 months is taken as 1, the change is small compared to the other samples except for Comparative Example 3. This suggests that there was little carbon dioxide leakage from the pores during the 3-month storage period, making the product less susceptible to air oxidation.

[0158] For Comparative Example 3, because it is a commercially available product, the type of coffee beans and the roasting method are unknown, but the change in the cumulative pore volume ratio due to storage is small. Despite the small change in cumulative pore volume, the reason Comparative Example 3 was judged to be "unsuitable for drinking" in the sensory taste evaluation after 3 months is thought to be because the cumulative pore volume of Comparative Example 3 is insufficient.

[0159] (8) Calculation of specific surface area Adsorption isotherms were measured at liquid nitrogen temperature using a multi-analyte gas adsorption analyzer (Anton Paar, Autosorb-iQ2-XR-VP) with nitrogen as the adsorbed gas. The specific surface area was calculated by the BET method from the nitrogen adsorption amounts at relative pressures of 0.25, 0.275, and 0.3. The results are shown in Table 11.

[0160] [Table 11]

[0161] The mocha-compatible products (Examples 1 to 3) showed the largest specific surface area at 0 months, which suggests that they also had a larger contact area with air compared to the other samples. However, when the ratio of the specific surface area is taken as 1 at 0 months, the change is small compared to Comparative Example 1, which suggests that there was little carbon dioxide leakage from the voids during the 3-month storage period, making them less susceptible to air oxidation.

[0162] For the roasted coffee beans used in Comparative Examples 2 to 6, the BET plot linearity of the specific surface area at 0 months was poor, making it impossible to calculate an accurate value. Similarly, for some roasted coffee beans at 1 month and 3 months, the specific surface area could not be calculated. This suggests that oils may have bled to the surface of these roasted coffee beans, making them susceptible to air oxidation. [Industrial Applicability]

[0163] As explained above, by storing the roasted coffee beans of the present invention, which have been roasted to a specified texture, for a long period of time in a storage container with a specified oxygen permeability, the flavor does not deteriorate, the coffee has a refreshing taste, and the diacetyl content, which is a cause of health problems, can be reduced.

[0164] Conventional aged roasted coffee beans begin to smell stale about one month after opening the package, so they must be consumed as soon as possible. In contrast, the aged roasted coffee beans of the present invention can be stored at room temperature in a delicious state even after opening the package, allowing consumers to enjoy the changes in flavor that occur with aging for a long period of time. The present invention provides a new genre of coffee that has never been seen before. [Explanation of symbols]

[0165] 10 Storage container 20 roasted coffee beans 30 Tea box 31 Case 32 Lid 31A, 32A metal layer

Claims

1. A plurality of roasted coffee beans, The surface color tones of the plurality of roasted coffee beans are measured using a color difference meter in an L*a*b* color system, with a standard deviation of the L* value being within ±0.8, and The roasted coffee beans are characterized by having a texture that satisfies the following (A) and (B): (A) The pore volume calculated by the nitrogen BJH method is 1.5 × 10 －３ cm 3 / g or more 3.0×10 －３ cm 3 / g or less. (B) The total volume of pores having a diameter of 20 Å to 200 Å calculated by the nitrogen BJH method is 1.5 × 10 －３ cm 3 / g or more.

2. A plurality of roasted coffee beans as described in claim 1, characterized in that no beans other than roasted coffee beans having a tissue structure that satisfies (A) and (B) are mixed in.

3. A method for aging roasted coffee beans, comprising: Roasted coffee beans having a texture that satisfies the following (A) and (B) are subjected to an oxygen permeability test at 5000 cm 3 / m ２ ・24h・ATM or more 20000cm 3 / m ２ A method for aging roasted coffee beans, comprising a aging step of aging at room temperature in a storage container for 24 hours atm or less. (A) The pore volume calculated by the nitrogen BJH method is 1.5 × 10 －３ cm 3 / g or more 3.0×10 －３ cm 3 / g or less. (B) The total volume of pores having a diameter of 20 Å to 200 Å calculated by the nitrogen BJH method is 1.5 × 10 －３ cm 3 / g or more.

4. 4. The method for aging roasted coffee beans according to claim 3, wherein in the aging step, the storage container is stored in a wooden container whose inner surface is coated with a metal layer.

5. A plurality of aged roasted coffee beans that have been roasted for at least one month, The surface color tones of the plurality of aged roasted coffee beans are measured with a color difference meter in an L*a*b* color system, with a standard deviation of the L* value being within ±0.8, and The aged roasted coffee beans are a plurality of aged roasted coffee beans characterized by having a texture that satisfies the following (A) and (B): (A) The pore volume calculated by the nitrogen BJH method is 1.5 × 10 －３ cm 3 / g or more 3.0×10 －３ cm 3 / g or less. (B) The total volume of pores having a diameter of 20 Å to 200 Å calculated by the nitrogen BJH method is 1.5 × 10 －３ cm 3 / g or more.

6. 6. The plurality of aged roasted coffee beans according to claim 5, characterized in that the diacetyl content is 70 ng / g or less.

7. A plurality of aged roasted coffee beans as described in claim 5, characterized in that no beans other than aged roasted coffee beans having a tissue structure that satisfies (A) and (B) are mixed in.

8. A plurality of aged roasted coffee beans according to any one of claims 5 to 7 packed in a storage container, The storage container has an oxygen permeability of 5000 cm 3 / m ２ ・24h・ATM or more 20000cm 3 / m ２ - A plurality of packed aged roasted coffee beans characterized by being aged for 24 hours or less.

9. 9. The packed plurality of aged roasted coffee beans according to claim 8, wherein the storage container is a bag-shaped container made of resin and having a thickness of 20 μm or more and 200 μm or less.

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