Method of impregnating green coffee beans with caffeine

Abstract

The objective is to provide a caffeine impregnation method that allows caffeine to be infused into green coffee beans without compromising the beans' original flavor. [Solution] The method for impregnating green coffee beans with caffeine according to the present invention comprises a water absorption step (S12) in which the green coffee beans are immersed in a caffeine aqueous solution in a processing container under a first reduced pressure state to allow them to absorb water, and a drying step (S13) in which the green coffee beans that have absorbed the caffeine aqueous solution in the water absorption step (S12) are dried in the processing container under a second reduced pressure state.

Description

Technical Field

[0001] The present invention relates to a caffeine impregnation method for impregnating green coffee beans with caffeine in order to increase the amount of caffeine contained in the green coffee beans.

Background Art

[0002] While there is a demand for decaffeinated coffee (caffeine-free coffee) with caffeine removed to suppress the effects of caffeine on the body, there is also a significant demand for coffee with a relatively high amount of caffeine that has a strong awakening effect as a morning cup. In particular, when driving a car for a long time or during exam preparation, etc., the intake of caffeine that brings an effect of enhancing concentration and wakefulness is required.

[0003] Although it is possible to intake caffeine by energy drinks containing a large amount of caffeine, there is also a high demand for the intake of caffeine by aromatic and flavorful coffee beverages extracted from coffee beans. However, there is a limit to the amount of caffeine contained in coffee beverages extracted from coffee beans, which is not comparable to energy drinks or instant coffee with increased caffeine.

[0004] By the way, a treatment method for improving the flavor by absorbing an amino acid aqueous solution into green coffee beans has been proposed (see Patent Document 1). This flavor improvement treatment method obtains a remarkable flavor improvement effect by absorbing an aqueous solution containing an amino acid and an amino acid salt into green coffee beans before roasting that have been subjected to pressure treatment.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Although we attempted to use the above processing method to allow green coffee beans to absorb a caffeine solution, we were unable to achieve the desired caffeine absorption effect, and therefore could not provide flavorful coffee beans with increased caffeine content.

[0007] The present invention aims to provide a caffeine impregnation method that increases the caffeine content of green coffee beans by impregnating them with caffeine without compromising the original flavor of the beans. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a method for impregnating green coffee beans with caffeine, comprising: a water absorption step in which the green coffee beans are immersed in a caffeine aqueous solution in a processing container under a first reduced pressure state to allow them to absorb water; and a drying step in which the green coffee beans that have absorbed the caffeine aqueous solution in the water absorption step are dried in the processing container under a second reduced pressure state.

[0009] With this configuration, the water absorption process is carried out under a first reduced pressure state, allowing for faster water absorption compared to the water absorption process under atmospheric pressure. Furthermore, since the drying process is carried out under a second reduced pressure state, drying can be performed at a lower temperature and in a shorter time than under atmospheric pressure. As a result, the original flavor of the coffee beans is preserved, and the efficiency of caffeine absorption is also increased. In this specification, coffee beans before roasting are referred to as green coffee beans.

[0010] In the method for impregnating green coffee beans with caffeine according to the present invention, the first reduced pressure state can be configured to be a reduced pressure state of -95kPa to -97kPa in gauge pressure.

[0011] With this configuration, by reducing the gauge pressure to -95kPa to -97kPa, it becomes possible to absorb the caffeine aqueous solution 4 to 5 times faster than under atmospheric pressure.

[0012] In the method for impregnating green coffee beans with caffeine according to the present invention, the drying step can be configured such that the second reduced pressure state is a gauge pressure of -95 to -97 kPa and the temperature inside the processing container is 55°C to 58°C.

[0013] With this configuration, the second reduced pressure state is a gauge pressure of -95kPa to -97kPa, resulting in reduced-pressure distillation where the boiling point of the liquid decreases as the pressure decreases. This allows drying to be done at a low temperature of 55°C to 58°C inside the processing vessel, making drying 3 to 4 times faster than sun drying, and without compromising the original flavor of the beans. Furthermore, an improvement of about 10% to 13% in caffeine absorption efficiency can be expected compared to sun drying.

[0014] In the method for impregnating green coffee beans with caffeine according to the present invention, the drying step can be configured to dry the beans until they reach the moisture content measured before the water absorption step.

[0015] With this configuration, drying the coffee beans to the moisture content measured before the water absorption process allows for a short drying time without compromising the original flavor of the coffee beans. [Effects of the Invention]

[0016] According to the present invention, caffeine can be efficiently impregnated into green coffee beans in a short time without compromising the original flavor of the coffee beans, making it possible to provide a caffeine-enhanced coffee with a rich coffee flavor. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 is a schematic diagram of a vacuum processing device used to impregnate green coffee beans with caffeine. [Figure 2] Figure 2 is a flowchart of the process for impregnating green coffee beans with caffeine. [Modes for carrying out the invention]

[0018] Embodiments of the present invention will be described below with reference to the drawings.

[0019] Referring to Figure 1, a schematic explanation of a method for impregnating green coffee beans with caffeine using a vacuum processing device will be given. Figure 1 is a schematic diagram of a vacuum processing device for impregnating green coffee beans with caffeine. As shown in Figure 1, the vacuum processing device 11 includes a processing container 12 into which the raw material, green coffee beans, are put for processing, a vacuum device 13 for reducing the pressure inside the processing container 12, a pressure gauge 15 for measuring the pressure inside the processing container 12, a caffeine aqueous solution supply device 16 for supplying caffeine aqueous solution to the processing container 12, a heating device 18 for heating the processing container 12, and a stirring device 19 provided inside the processing container 12. Note that the vacuum processing device 11 is just an example and is not limited to this. As long as the water absorption process and drying process can be performed on the green coffee beans under reduced pressure, it is sufficient, for example, to directly put the caffeine aqueous solution into the processing container 12 without providing the caffeine aqueous solution supply device 16.

[0020] The processing container 12 and the pressure reducing device 13, and the processing container 12 and the caffeine aqueous solution supply device 16 are connected by pipes 21 and 22. A pressure gauge 15 is installed in pipe 21 connecting the processing container 12 and the pressure reducing device 13. The pressure reducing device 13 reduces the internal pressure of the processing container 12 below atmospheric pressure, and equipment such as an oil rotary vacuum pump or a dry vacuum pump is used. The pressure reducing device 13 reduces the internal pressure of the processing container 12 to a first reduced pressure state (gauge pressure of -95kPa to -97kPa) during the water absorption process, and to a second reduced pressure state (gauge pressure of -95kPa to -97kPa) during the drying process. Both the first and second reduced pressure states only need to be within the range of gauge pressure of -95kPa to -97kPa, and the first and second reduced pressure states do not need to be the same value. The internal pressure of the processing container 12 can be checked by the pressure gauge 15 and adjusted to be within the above pressure range.

[0021] The caffeine aqueous solution supply device 16 stores an aqueous solution obtained by adding natural caffeine to water and supplies it to the treatment container 12 via the pipe 22. The caffeine aqueous solution is, for example, an aqueous solution in which natural caffeine (about 222 g to about 680 g) is added to 22 liters of water, which is 1.1 times (22 kg) the amount of 20 kg of green coffee beans, to form an aqueous solution of about 1% to about 3%. In this embodiment, it is an aqueous caffeine solution, but fruit juice or flavoring can be added in place of or together with caffeine. It is also possible to provide a coffee beverage with a new flavor.

[0022] The heating device 18 is a device that heats the inside of the treatment container 12 in order to dry the green coffee beans that have undergone the water absorption process under reduced pressure. The heating device 18 may be of any type such as an electric heating type or a fuel heating type, and is provided with a control device (not shown) that controls it to reach a predetermined temperature. In this embodiment, it is drying under reduced pressure (gauge pressure of -95 kPa to -97 kPa), and since the boiling point drops, the temperature inside the treatment container 12 is set within the range of 55°C to 58°C. The stirring device 19 stirs the green coffee beans inside the treatment container 12 and is used in both the water absorption process and the drying process so that water absorption and drying are carried out evenly throughout.

[0023] Regarding the green coffee beans used in this embodiment, any of Arabica, Robusta, and Liberica varieties may be used, and the origin of the green coffee beans is not particularly limited. Furthermore, the green coffee beans may be of a single type or a blend of several types. The present invention relates to a method of impregnating these green coffee beans with caffeine. The moisture content, which is the amount of moisture contained in the green coffee beans as raw materials before the water absorption step, is measured. This is because when shifting to the drying step after the water absorption step, drying is performed until the initial moisture content measured before the water absorption step is reached. Therefore, the moisture content is also measured in the drying step. Green coffee beans usually have a moisture content of about 9% to 13%. As equipment for measuring the moisture content, an electric moisture meter, an optical moisture meter, etc. are used. An electric moisture meter is a device that passes electricity through the substance to be measured to measure the amount of moisture, and an optical moisture meter is a device that shines light on the object and measures the amount of moisture based on the amount of reflected light. In addition to the above, there are also devices that measure the moisture content of green coffee beans by applying pressure to the coffee beans or using microwaves, infrared rays, high-frequency electric fields, etc., and these can also be used.

[0024] Next, the procedure of the processing steps for impregnating green coffee beans with caffeine will be described with reference to FIG. 2. FIG. 2 is a flowchart of the processing steps for impregnating green coffee beans with caffeine. Appropriate reference is made to FIG. 1 showing the vacuum processing device 11 as needed. As shown in FIG. 2, the moisture content of the raw green coffee beans is measured by a moisture measuring device (S11). The moisture measuring device may be any of those described above, and a commercially available moisture content measuring device dedicated to coffee beans can be used.

[0025] In this embodiment, 22 liters of water (22 kg), which is 1.1 times the amount of green coffee beans, are used for 20 kg of green coffee beans. Natural caffeine (approximately 222 g to 680 g) is added to the 22 liters of water to create a caffeine aqueous solution with a caffeine concentration of approximately 1% to 3%. The caffeine aqueous solution is stored in the caffeine aqueous solution supply device 16. 20 kg of green coffee beans are placed inside the processing container 12, and the caffeine aqueous solution is supplied. The pressure is then reduced to a first reduced pressure state (gauge pressure of -95 kPa to -97 kPa) by the depressurization device 13, and the water absorption process is started to allow the green coffee beans to absorb the water (S12). The time required for the water absorption process is approximately 3 hours, which is about 12 hours in the water absorption process under atmospheric pressure. Therefore, water can be absorbed 4 to 5 times faster than in the water absorption process under atmospheric pressure. In this water absorption process, the green coffee beans are stirred by the stirring device 19 at a rate of once every few minutes to ensure even water absorption. The water absorption process is terminated when it is confirmed that there is no excess water in the caffeine solution.

[0026] Next, the inside of the processing container 12 is maintained in a second reduced pressure state (gauge pressure of -95kPa to -97kPa), which is the same pressure range as the first reduced pressure state, and the heating device 18 heats the inside of the processing container 12 to a temperature of 55°C to 58°C to dry the green coffee beans in the drying process (S13). The drying process takes about 10 hours, which is 3 to 4 times faster than conventional sun drying. By performing low-temperature, short-time drying under reduced pressure according to this embodiment (reduced-pressure distillation), the original flavor of the coffee beans can be preserved during drying. In the drying process, the green coffee beans are stirred by the stirring device 19 at a rate of once every tens of minutes in order to ensure uniform drying of the green coffee beans.

[0027] Once the drying process has progressed and the moisture content of the green coffee beans has reached the level measured before the water absorption process, the drying process is terminated (S14).

[0028] According to this embodiment, by allowing green coffee beans to absorb a caffeine solution under a first reduced pressure state (gauge pressure of -95kPa to -97kPa) inside the processing container 12, the absorption time could be shortened from 12 hours to 3 hours compared to the conventional method under atmospheric pressure. Furthermore, by using a second reduced pressure state (gauge pressure of -95kPa to -97kPa), the inside of the processing container 12 can be dried at a lower temperature (boiling point of approximately 50°C) compared to conventional drying under atmospheric pressure, thus preserving the flavor. The flavor was improved compared to conventional drying in a food drying oven under atmospheric pressure. Moreover, by performing both the caffeine aqueous solution supply process and the subsequent drying process under reduced pressure, the caffeine absorption efficiency of green coffee beans was improved by approximately 10% to 13% compared to the conventional method under atmospheric pressure.

[0029] The green coffee beans that have undergone the above drying process are then roasted, ground, and the coffee liquid is extracted by drip or other methods. The roasting method is carried out using a rotating drum or the like, using known methods such as direct-fire or hot-air roasting. Regardless of the degree of grinding or the extraction method, the green coffee beans provided in this embodiment can be used to obtain a coffee beverage that is flavorful and has increased caffeine content.

[0030] Although several embodiments and modifications of the present invention have been described above, these embodiments and modifications are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments described above can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the invention described in the claims. [Industrial applicability]

[0031] According to the method for impregnating green coffee beans with caffeine according to the present invention, caffeine can be efficiently impregnated into green coffee beans in a short time without impairing the original flavor of the coffee beans, making it useful as a flavorful coffee bean with increased caffeine content. [Explanation of symbols]

[0032] 11. Vacuum treatment device 12 Processing container 13. Pressure reducing device 15. Pressure gauge 16. Caffeine aqueous solution supply device 18 Heating device 19 Stirring device 21, 22 Piping

Claims

1. A water absorption step is performed by creating a first reduced-pressure state inside the processing container and immersing the green coffee beans in a caffeine aqueous solution to allow them to absorb water, The coffee beans that have absorbed the caffeine aqueous solution in the water absorption step are dried in a drying step in which the processing container is subjected to a second reduced pressure state. A method for impregnating green coffee beans with caffeine.

2. The method for impregnating green coffee beans with caffeine according to claim 1, wherein the first reduced pressure state is a reduced pressure state of -95 kPa to -97 kPa in gauge pressure.

3. The method for impregnating green coffee beans with caffeine according to claim 1, wherein in the drying step, the second reduced pressure state is a reduced pressure state of -95 kPa to -97 kPa in gauge pressure, and the temperature inside the processing container is 55°C to 58°C.

4. The method for impregnating green coffee beans with caffeine according to any one of claims 1 to 3, wherein the drying step is performed to dry the beans until the moisture content of the green coffee beans is measured before the water absorption step.

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