JP7618185B2 - Coffee bean roasting device and coffee bean roasting method - Google Patents

Description

The present invention relates to a coffee bean roasting device and a method for roasting and producing coffee beans.

Typical heat sources for generating hot air in coffee bean roasting devices include burners that burn natural gas, liquefied petroleum gas, wood, etc., as well as heat sources such as electric heaters, halogens, infrared rays, and microwaves (see, for example, Patent Documents 1 and 2).

Examples of burners include burners equipped with nozzles that supply one type of fuel and one type of oxidizer, and multi-fuel burners equipped with nozzles that supply multiple types of fuel (hydrogen, city gas) and one type of oxidizer (air) (see, for example, Patent Document 3).

Special Publication No. 2022-537262 Patent No. 6173395 Patent No. 7064474

Burners that use hydrocarbon fuels such as city gas as a heat source for generating hot air inevitably generate carbon dioxide. Therefore, as a measure against global warming, it is expected that the generation of carbon dioxide will be suppressed even in coffee bean roasting devices.
In addition, although the above-mentioned multi-fuel burner discloses the use of hydrogen, it does not disclose its use in a coffee bean roaster. In particular, in order to use it in a coffee bean roaster, it is necessary to reproduce the same taste as that of a conventional roaster.

A first object of the present disclosure is to provide a coffee bean roasting device and a coffee bean roasting production method that can reproduce a taste equivalent to that of conventional roasting devices while using a burner that uses hydrogen as fuel.
A second object is to provide a coffee bean roasting device and a coffee bean roasting method that can generate hot air free of carbon dioxide.
A third object is to provide a coffee bean roasting device and a coffee bean roasting method that enable the mixing ratio of hydrogen and hydrocarbon fuel to be freely set in the multi-fuel burner.
A fourth object is to provide a coffee bean roasting apparatus and a coffee bean roasting method that can design a new roasting profile by using a high turndown ratio in a hydrogen burner.
A fifth object is to provide a coffee bean roasting device and a coffee bean roasting method that use a high turndown ratio in a hydrogen burner to improve taste or increase healthful components after roasting.

The coffee bean roasting device (1) comprises:
An adjustable hydrogen co-fuel burner (10) using hydrogen and a hydrocarbon fuel and having a turndown ratio of 1:10 or more;
A roaster (20) that uses hot air generated by the hydrogen-mixed combustion burner as a heat source for roasting;
a control device (30) for controlling the hydrogen-mixed combustion burner in accordance with a roasting profile of coffee beans (hot air temperature setting value data (SV_t) in roasting);
Equipped with.
Examples of "hydrocarbon fuels" include city gas, propane gas, and ethane gas.
A "hydrogen-mixed burner" may use only hydrogen fuel.
The "roaster" may be a hot air roaster or a semi-hot air roaster.
The "controller" may control the roaster and/or the hydrogen co-fuel burner.

The coffee bean roasting apparatus (1) comprises:
A temperature measuring device (40) is provided for measuring the temperature of the hot air generated by the hydrogen-mixed combustion burner (10),
The control device (30)
The hydrogen-mixed combustion burner (10) may be feedback-controlled so that the measured temperature (PV_t) measured by the temperature measuring device (40) corresponds to a roasting profile of the coffee beans.
One or more of said temperature measuring devices (40) may be provided in any pre-roast hot air supply piping, roaster internal piping, or post-roast hot air exhaust piping.

The coffee bean roasting apparatus (1) comprises:
A temperature measuring means may be provided to measure the temperature of the coffee beans (or the surrounding atmospheric temperature) during roasting.
The temperature measuring means may be a thermometer that measures the temperature by contacting the coffee beans, or a non-contact thermometer.

The roasting profile may be stored in the memory of the device (1) or the control device (30). The roasting profile may be sent from an external device. The device (1) may have a profile setting unit that sets the roasting profile.

The roasting profile is set to provide a product temperature curve during roasting that can improve the taste, aroma, and health benefits of coffee. The present invention can provide a product temperature curve that cannot be achieved with conventional 100% natural gas burners.
The product temperature curve is a downward convex curve, and when divided into three parts, the early stage of roasting, the middle stage of roasting, and the late stage of roasting, there is a period in which the temperature is maintained at 180°C or higher in the early stage of roasting, the temperature is gradually decreased from the early stage of roasting to reach a minimum value in the middle stage of roasting, and the temperature is gradually increased from the middle stage of roasting to the late stage of roasting. For example, there is the following product temperature curve.
(1) There is a period in which the slope (rate of increase) of temperature rise in the latter half of the late roasting stage is smaller than the slope (rate of increase) of temperature rise from the middle to the late roasting stage.
(2) In the early stage of roasting, there is a period during which the slope of the temperature decrease toward the minimum value that is downwardly convex in the middle of roasting is higher than the slope (decrease rate) of the temperature decrease that can be achieved with a natural gas burner.
(3) The rate of temperature decrease before the minimum value of the downward convexity, the temperature of the minimum value of the downward convexity, and the rate of temperature increase after the minimum value of the downward convexity are set so as to maintain the taste and aroma and suppress the thermal decomposition of healthful ingredients.
The product temperature may be a value measured by a thermometer placed in a position that makes direct contact with the beans during roasting, or a value measured by a non-contact thermometer on the beans during roasting.
(4) In the roasting profile, the maximum temperature in the early stage of roasting can be set to be lower than, equal to, or higher than the maximum temperature in the later stage of roasting.

The hydrogen-mixed combustion burner (10) is
A burner body (11),
A burner tip (12);
a hydrogen supply nozzle (13) disposed inside the burner body (11) and having a nozzle tip with a circular cross section for supplying hydrogen;
an oxidizer supply nozzle (14) having a ring-shaped cross section, which is disposed inside the burner body (11) and provided outside the hydrogen supply nozzle, for supplying an oxidizer (e.g., air, oxygen);
A fuel supply nozzle (15) that is disposed inside the burner body and is provided outside the oxidizer supply nozzle and has a ring-shaped cross section and supplies a hydrocarbon-based fuel;
The device may include:
The hydrogen-mixed combustion burner (10) is
A hydrogen source (S2) (e.g., a main pipe, a tank, a cylinder) having a predetermined pressure, a hydrogen pipe (L2), a valve (V2) (e.g., a control valve, a gate valve) provided in the hydrogen pipe (L2), an optional gas flow meter, and an optional gas pressure gauge,
An oxidizer source (S1) of a predetermined pressure (e.g., a main pipe, a bomb, a cylinder, a pressure pump, a compressor), an oxidizer pipe (L1), a valve (V1) (e.g., a control valve, a gate valve) provided in the oxidizer pipe (L1), an optional gas flow meter, and an optional gas pressure gauge,
A hydrocarbon fuel source (S3) (e.g., a main pipe, a tank, a cylinder) having a predetermined pressure, a hydrocarbon fuel pipe (L3), a valve (V3) (e.g., a control valve, a gate valve) provided in the hydrocarbon fuel pipe (L3), an optional gas flow meter, and an optional gas pressure gauge,
The device may include:
The control device (30)
The combustion power (heat power) may be controlled (the mixed combustion ratio may be controlled) by adjusting the valve opening of one or more of the valves provided in the hydrogen pipe, the valve provided in the oxidizer pipe, and the valve provided in the hydrocarbon fuel pipe. The control device (30) may proportionally control the valve opening in response to an increase or decrease in the combustion power (heat power).

The hydrogen-mixed combustion burner (10) is
a circulation pipe (L10) for circulating hot air (waste gas) from the tip of the burner to the oxidizer pipe (L1); a suction pump (P10) provided in the circulation pipe (L10); a valve (e.g., a control valve, a gate valve) provided in the circulation pipe (L10); an optional gas flow meter; and an optional gas pressure gauge.
The device may include:
The control device (30)
The amount of hot air (waste gas) circulated may be controlled by adjusting the operation of a suction pump (P10) provided in the circulation pipe (L10) and the opening degree of a valve (V10) (e.g., a control valve, a gate valve) provided in the circulation pipe (L10).

The coffee bean roasting apparatus (1) comprises:
The roaster may also include a storage device (31) for storing said roast profile.

Coffee bean roasting method:
A method for roasting coffee beans using hot air generated by an adjustable hydrogen-mixed combustion burner with a turndown ratio of 1:10 or more,
The method includes a control step of controlling the hydrogen-mixed combustion burner in accordance with the roasting profile of the coffee beans.
The control step includes:
The hydrogen-mixed combustion burner may be feedback-controlled so that the measured temperature (PV_t) of the hot air measured by the temperature measuring device corresponds to the roasting profile of the coffee beans.
The control step includes:
The combustion power (heat power) may be controlled (the mixed-fuel ratio may be controlled) by adjusting the valve opening of one or more of the valves provided in the hydrogen piping, the valves provided in the oxidizer piping, and the valves provided in the hydrocarbon fuel.
The control step includes:
The amount of circulating waste gas may be controlled by adjusting the drive of a suction pump provided in the circulation pipe and the opening degree of a valve provided in the circulation pipe.

"Coffee beans" includes all coffee beans, regardless of origin (brand) or type.

The control device may be configured as an information processing device (e.g., a computer or a server) having a memory, a processor, and a software program, or as a dedicated circuit, firmware, etc. The information processing device may be either on-premise or cloud-based, or a combination of both.

(effect)
(1) By using a hydrogen-fueled burner, it is possible to reproduce the same taste as that achieved by conventional roasting devices that use natural gas, etc.
(2) Carbon dioxide-free operation can be achieved when hot air is generated.
(3) The mixture ratio of hydrogen and hydrocarbon fuel in the multi-fuel burner can be freely set.
(4) High turndown ratios can be used in hydrogen burners, allowing new roast profiles to be designed.
(5) A high turndown ratio can be used in the hydrogen burner, allowing for improved taste, aroma, and enhanced healthful properties after roasting.

FIG. 1 is a diagram showing an example of a coffee bean roasting device of embodiment 1. FIG. 2 is a diagram showing an example of the structure of a multi-fuel burner. FIG. 2 is a diagram showing an example of a piping configuration of a multi-fuel burner. FIG. 2 shows an example of a product temperature curve and roasting profile. FIG. 13 shows an example of a product temperature curve and roasting profile for Example 3. FIG. 1 is a diagram showing a radar chart. FIG. 13 is a diagram showing an example of a product temperature curve in Example 4. FIG. 13 is a diagram showing an example of a product temperature curve in Example 5. FIG. 13 is a diagram showing an example of a product temperature curve in Example 6.

(Embodiment 1)
Figure 1 shows an example of the function of the coffee bean roaster 1 of the first embodiment. Figure 2 shows an example of the structure of a multi-fuel burner. Figure 3 shows an example of the piping configuration of a multi-fuel burner. Figures 1 to 3 show examples of the configuration and function, and are not limited thereto, and various configuration changes are possible.

The coffee bean roasting device 1 includes a hydrogen-mixed combustion burner 10, a roaster 20, a control device 30, a memory device 31, and a temperature measuring device 40.

The hydrogen-mixed burner 10 uses hydrogen and hydrocarbon fuel and has an adjustable burner function with a turndown ratio of 1:10 or more. It is also possible to stop the supply of hydrocarbon fuel and supply only hydrogen fuel. The turndown ratio is 1:10 or more, but 1:15 or 1:20 is preferable. In this embodiment, the hydrocarbon fuel is compressed natural gas, but is not limited to this. The hydrogen fuel is compressed hydrogen at 0.1 MPa. The oxidizer is air.

The structure of the hydrogen-mixed combustion burner 10 will be described with reference to Fig. 2. The hydrogen-mixed combustion burner 10 includes a burner body 11 and a burner tip portion 12. The opening area of the burner tip portion 12 increases toward the tip.
Formed inside the burner body 11 are a hydrogen supply nozzle 13 with a nozzle tip having a circular cross section for supplying hydrogen, an oxidizer supply nozzle 14 with a ring-shaped cross section for supplying air and provided outside the hydrogen supply nozzle 13, and a fuel supply nozzle 15 with a ring-shaped cross section for supplying compressed natural gas and provided outside the oxidizer supply nozzle 14. The hydrogen fuel and natural gas are not brought into direct contact with each other, but an oxidizer is injected between them, forming a mixing region suitable for each fuel.

The roaster 20 uses the hot air generated by the hydrogen-mixed combustion burner 10 as a heat source for roasting. The roaster 20 of this embodiment is a drum-type hot air roaster or a fluidized bed-type hot air roaster.
The control device 30 controls the hydrogen-mixed combustion burner 10 in accordance with the roasting profile of the coffee beans. The storage device 31 stores the roasting profile 311. The roasting profile 311 includes hot air temperature set value data (SV_t) corresponding to the roasting time.

The piping configuration of the hydrogen-mixed combustion burner 10 will be described with reference to Figure 3. The hydrogen-mixed combustion burner 10 includes a 0.1 MPa compressed hydrogen cylinder S2, a hydrogen pipe L2, a flow rate control valve V2 with a flow meter provided on the hydrogen pipe L2, an air pump P, an air pipe L1, a flow rate control valve V1 with a flow meter provided on the air pipe L1, a compressed natural gas cylinder S3, a natural gas pipe L3, and a flow rate control valve V3 with a flow meter provided on the natural gas pipe L3.
The hydrogen-mixed combustion burner 10 includes a circulation pipe L10 for circulating hot air (waste gas) from the burner tip 12 to an air pipe L1, a suction pump P10 provided in the circulation pipe L10, and a flow rate control valve with a flow meter provided in the circulation pipe L10.
The temperature measuring device 40 is provided in the hot air supply pipe before roasting. The temperature measuring device 40 measures the temperature of the hot air generated by the hydrogen-mixed combustion burner 10.
Hot air from the hydrogen-mixed combustion burner 10 is sent to the fluidized bed 21 of the roaster 20.

The burner control unit 101 of the hydrogen-mixed combustion burner 10 can control the combustion (proportional control of the fuel supply amount and the air supply amount) in response to the roasting profile 311 and the command from the control device 30. The control device 30 may perform feedback control by issuing a command to the burner control unit 101 of the hydrogen-mixed combustion burner 10 so that the measured temperature (PV_t) measured by the temperature measuring device 40 corresponds to the roasting profile 311.
The control device 30, directly or by issuing a command to the burner control unit 101, adjusts the valve opening of one or more of the flow control valves V2 provided in the hydrogen pipe L2, the flow control valve V1 provided in the air pipe L1, and the flow control valve V3 provided in the natural gas pipe L3, thereby controlling the combustion power (thermal power). It can control the ratio of the supply amounts of hydrogen and natural gas, and the air amount. It can proportionally control the opening of each valve according to the increase or decrease in the combustion power (thermal power).
The control device 30 can control the start/stop of circulation of hot air (waste gas) and the circulation amount by adjusting the drive of the suction pump P10 provided in the circulation pipe L10 and the valve opening of the flow rate control valve V10 provided in the circulation pipe L10, either directly or by issuing a command to the burner control unit 101. When the combustion power (fire power) is to be reduced, the circulation can be started or the circulation amount can be increased to control the reduction of the oxygen concentration supplied to the burner. This can also reduce the amount of NOx generated.

According to this embodiment, the mixture ratio of hydrogen and hydrocarbon fuel can be freely set in the multi-fuel burner. A high turndown ratio can be used in the hydrogen burner, and a new roasting profile (product temperature curve) can be designed. A high turndown ratio can be used in the hydrogen burner, and it is possible to improve the taste, aroma, and enhance the health components after roasting.
Examples of "taste" include sourness, richness, bitterness, and aroma (fragrance). Since aroma stimulates the sense of smell, it can also be said that it improves the sense of smell. A new roasting profile (product temperature curve) with a high turndown ratio, which is not possible with conventional hydrocarbon fuel burners, can suppress the deterioration of taste components.
Examples of "healthy components" include chlorogenic acids and trigonelline. It is known that healthy components are decomposed at high temperatures. A new roasting profile (product temperature curve) with a high turndown ratio, which is not possible with conventional hydrocarbon fuel burners, can suppress the thermal decomposition of healthy components.

(Examples 1 and 2)
Examples 1 and 2 of roasting using the hydrogen-mixed combustion burner in the first embodiment and Comparative Example 1 of roasting using a normal compressed natural gas burner will be described.
Coffee beans: 5kg
Roasting time: 15 minutes Heat source: Hydrogen 0.1MPa
: Natural gas 10kPa (0.01MPa)
Mixed combustion conditions (Example 1): Hydrogen:Natural gas=50%:50% (heat ratio)
Hydrogen only (Example 2): 100% hydrogen
Supply pressure: 10 kPa

Figure 4 shows an example of the product temperature curve and roasting profile during roasting. An example of the roasting profile (hot air temperature setting conditions) for the burners of Examples 1 and 2 and Comparative Example 1 is shown. Example 1 is shown by a solid line, Example 2 by a dashed and dotted line, and Comparative Example 1 by a dashed line. Each roasting profile is different in order to achieve the same product temperature curve. The product temperature is a value measured by a thermometer installed in a position that is in direct contact with the beans being roasted.

(Taste evaluation)
A taste evaluation was carried out for each of Examples 1 and 2 and Comparative Example 1.
The method for obtaining the extract is as follows.
Extraction method: Paper drip method Extraction conditions: 20g ground coffee, 320g hot water, 20 seconds steeping time Sensory evaluation Subjects: 14 people Extracted samples were blinded and absolute evaluation was performed according to the following sensory evaluation criteria (N=14). The strength of the taste in five categories (acidity, bitterness, astringency, richness, aftertaste) was evaluated on a 9-level scale (from -4 (very weak) to +4 (very strong), with the median value 0 being normal).
A significance test (t-test: significance level 5%) was conducted on the evaluation results in Table 1 using the roasted product of Comparative Example 1 (natural gas) as the standard. Both Example 1 (mixed combustion) and Example 2 (hydrogen only combustion) were able to produce a taste equivalent to that of conventional fuel roasting.

(Roast level (L value) evaluation)
The roast level (L value) of each of Examples 1 and 2 and the Comparative Example was evaluated.
Roast level: Colorimeter (ZE-6000, manufactured by Nippon Denshoku Industries Co., Ltd.)
The measurement results of the roast level (L value) are shown in Table 2. The L value for each was within 20.2±0.1, indicating that the roast levels were the same.

(Hydrogen-only burner: Example 3)
In the hydrogen-mixed combustion burner in the first embodiment, only hydrogen fuel is used (hereinafter, referred to as a "hydrogen-only burner") to implement a new roasting control that cannot be performed with conventional fuel burners.
The hydrogen-only burner has a turndown ratio of 1:20 in this embodiment, which is greater than the conventional turndown ratio of 1:5. The combustion power level can be set much lower than with conventional fuels.

(conditions)
Coffee beans: 5kg
Roasting time: 17 minutes Heat source: Hydrogen 0.1MPa
Hydrogen only (Example 3): 100% hydrogen
Hydrogen only (Reference Example 1): 100% hydrogen
Comparative Example 2: 100% natural gas
Supply pressure: 10 kPa

Figure 5 shows an example of a product temperature curve and roasting profile during roasting. An example of a roasting profile (hot air temperature setting conditions) in Example 3 is shown. Example 3 is shown with a dashed line. Reference Example 1 is shown with a solid line, and Comparative Example 2 is shown with a dashed line. Comparative Example 2 was set by approximating the product temperature curve of Example 3. Since the turndown ratios are different, it is not possible to set the same product temperature curve, and the roasting profiles are significantly different from each other.
The product temperature curve of Example 3 has a period in which the temperature rise slope after the minimum value of the downward convexity in the middle of roasting is smaller than that of Comparative Example 2, thereby improving the taste. Example 3 also has an inflection point in the later stage of roasting.

(Taste evaluation)
A taste evaluation was carried out for each of Example 3 (hydrogen only combustion), Comparative Example 2 (natural gas), and Reference Example 1.
The method for obtaining the extract is as follows.
Extraction method: Paper drip method Extraction conditions: 20g ground coffee, 320g hot water, 20 seconds steeping time (A) Sensory evaluation Subjects: 14 people Extracted samples were blinded and absolute evaluation was performed according to the following sensory evaluation criteria (N=14). The strength of the five taste items was rated on a 9-level scale (from -4 (very weak) to +4 (very strong), with the median value 0 being normal).
For the evaluation results in Table 3, a significance test (t-test: significance level 5%) was performed using the roasted product of Reference Example 1 as the standard.

(Roast level (L value) evaluation)
The roast level (L value) of each of Reference Example 1, Example 3 and Comparative Example 2 was evaluated.
Roast level: Colorimeter (ZE-6000, manufactured by Nippon Denshoku Industries Co., Ltd.)
The measurement results of the roast level (L value) are shown in Table 4. The L value for each was within 20.9±0.3, indicating that the roast levels were the same.

(C) Taste sensor Analysis device: Taste recognition device manufactured by Intelligent Sensor Technology (model: SA402B)
The extract was cooled to room temperature (20°C), and the taste of the coffee ('acidity', 'bitterness', 'astringency', 'richness', 'aftertaste of bitterness', and 'full-bodied umami') was measured using five taste sensors, namely 'CA0 (acidity)', 'CT0 (saltiness)', 'C00 (bitterness/irritation)', 'AE1 (astringency)', and 'AAE (umami)', using the SA402B taste sensor.
For each analysis batch, a bottled black coffee extract with a Brix value (indicating coffee concentration) of 1.05 and a pH of 5.70 was measured as a reference sample, and the difference between the analytical results of each coffee and the reference sample was used as taste data.
The taste score of Reference Example 1 was set as the standard "0", and the difference from the standard was shown in a radar chart (Figure 6).
The taste sensor also confirmed that the sourness of Example 3 (hydrogen only combustion) was strong.
In Example 3 (hydrogen only), a taste was created that could not be achieved with conventional fuel roasting.

(Example 4: Fragrance Improvement)
(conditions)
Coffee beans: 5kg
Roasting time: 12 minutes Heat source: Hydrogen 0.1MPa
Example 4: 100% hydrogen
Comparative Example 4: 100% natural gas
Reference Example 4: 100% natural gas (standard roast)
Supply pressure: 10 kPa

Figure 7 shows an example of a product temperature curve during roasting. Example 4 is shown with a dashed line, Reference Example 4 with a solid line, and Comparative Example 4 with a dashed line. Reference Example 4 is a standard roasting temperature curve. The product temperature curve of Example 4 has a high temperature period due to high heat in the early stage of roasting, and a period in the latter half of the late roasting period in which the temperature rise slope is smaller than that of Comparative Example 3, thereby improving the aroma. The roasting profile of Comparative Example 4 was set to be close to the product temperature curve of Example 4, but it was not possible to make the temperature rise slope smaller in the latter half of the late roasting period as in Example 4.

(aroma)
The aroma of the coffee powder of Example 4 (hydrogen only combustion), Reference Example 4 (standard), and Comparative Example 4 (natural gas) was measured. The method for measuring the aroma of the coffee powder is as follows.
[Measurement of aroma components by gas chromatography]
The amount of aroma components contained in the coffee liquid was analyzed by gas chromatography under the following conditions, and the total area of the peaks was calculated as the total amount of aroma.
(a) Preparation of measurement samples: 3 g of each coffee powder was placed in a vial and sealed. The sealed vial was heated at 80° C. for 30 minutes using a gas chromatography autosampler HS-20NX, and the gas phase was introduced into a gas chromatograph for analysis.
(b) Measurement conditions Measuring device: Shimadzu Gas Chromatograph GC-2030
Column: GL Sciences TC-WAX (Φ0.32 mm×60 m DF 0.50 μm)
Carrier gas: helium Column flow rate: 3.52 ml/min Column temperature: 40° C. 0 min → 55° C. 1 min (heating at 5° C./min) → 80° C. 1 min (heating at 10° C./min) → 120° C. 1 min (heating at 12° C./min) → 180° C. 1 min (heating at 15° C./min) → 215° C. 1 min (heating at 15° C./min)
Detector: FID (detector temperature 240° C.)
The measurement results of the total aroma amount are shown in Table 5. (The standard total aroma amount is shown as "100.") Example 4 had a total aroma amount 12.6% higher than Reference Example 4 (standard), confirming that the hydrogen burner was able to increase the aroma compared to the natural gas burner. The L value was measured using the same method as above.

(Example 5: Increase in chlorogenic acids)
(conditions)
Coffee beans: 5kg
Roasting time: 17 minutes Heat source: Hydrogen 0.1MPa
Example 5: 100% hydrogen
Comparative Example 5: 100% natural gas
Reference Example 5: 100% natural gas (standard roast)
Supply pressure: 10 kPa

Figure 8 shows an example of a product temperature curve during roasting. Example 5 is shown as a square plot line, Reference Example 5 as a circle plot line, and Comparative Example 5 as a triangle plot line. Reference Example 5 is a standard roasting temperature curve. The product temperature curve of Example 5 has a large temperature decrease rate in the early stage of roasting, and has a low temperature period area to gently apply heat in the early stage of roasting. The minimum value of the downward convexity is also a temperature lower than the standard, and is raised to the same temperature as the standard in the latter half of the late stage of roasting. The roasting profile of Comparative Example 5 was set to approach the product temperature curve of Example 5, but a product temperature curve like that of Example 5 could not be realized.

(chlorogenic acid content)
The amount of chlorogenic acids and the total aroma were measured for Example 5 (hydrogen combustion only), Reference Example 5 (standard), and Comparative Example 5 (natural gas). "Chlorogenic acids" is a general term for mono-caffeoylquinic acids such as 3-caffeoylquinic acid (3-CQA), 4-caffeoylquinic acid (4-CQA), and 5-caffeoylquinic acid (5-CQA), mono-feruloylquinic acids such as 3-feruloylquinic acid (3-FQA), 4-feruloylquinic acid (4-FQA), and 5-feruloylquinic acid (5-FQA), and 3,4-dicaffeoylquinic acid (3,4-diCQA), 3,5-dicaffeoylquinic acid (3,5-diCQA), and 4,5-dicaffeoylquinic acid (4,5-diCQA).

The method for obtaining the extract is as follows.
Extraction method: Paper drip method Extraction conditions: 20 g of coffee powder, 320 g of hot water poured, 20 seconds of steeping time The obtained extract was cooled to room temperature (20°C) and the amount of chlorogenic acids was measured using high performance liquid chromatography under the following analytical conditions.
Column: Inertsil(R) ODS-3 (particle size: 5 μm, inner diameter: 4.6 mm, length: 150 mm)
Column oven temperature: 35°C
Mobile phase: Solution A: 30 mg/L HEDP-containing water-acetonitrile-acetic acid (1000:50:3, v/v/v)
B solution: acetonitrile C solution: methanol Flow rate: 0.8 mL/min
Sample injection volume: 10 μL
Detection wavelength: 324 nm
Gradient conditions: shown in Table 6.

The concentrations (μg/mL) of 3-CQA, 4-CQA, 5-CQA, 3-FQA, 4-FQA, 5-FQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA converted to 5-caffeoylquinic acid (5-CQA) are calculated from the area values of the nine chlorogenic acids measured using 5-caffeoylquinic acid as the standard substance. 3-CQA, 4-CQA, 3-FQA, 4-FQA, 5-FQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA are converted to the concentrations (μg/mL) of each chlorogenic acid (CGA) using (Formula 1).
(Formula 1):
CGA (μg/mL) = [CGA concentration converted to 5-CQA (μg/mL)] × (ε _5-CQA /M _5-CQA ) × (M _CGA /ε _CGA )
Here, CGA represents any one of 3-CQA, 4-CQA, 3-FQA, 4-FQA, 5-FQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA. ε _CGA represents the molar absorption coefficient of each chlorogenic acid, and the respective values are as follows.
ε _3-CQA = 1.84×10 ⁻⁴ (L/(mol・cm)),
ε _4-CQA = 1.80×10 ⁻⁴ (L/(mol・cm)),
ε _5-CQA = 1.95×10 ^-4 (L/(mol・cm)),
ε _3-FQA = 1.90×10 ^-4 (L/(mol・cm)),
ε _4-FQA = 1.95×10 ^-4 (L/(mol・cm)),
ε _5-FQA = 1.93×10 ^-4 (L/(mol・cm)),
ε _3,4-diCQA = 3.18×10 ⁻⁴ (L/(mol・cm)),
ε _3,5-diCQA = 3.16×10 ⁻⁴ (L/(mol・cm)),
ε _4,5-diCQA = 3.32×10 ⁻⁴ (L/(mol・cm))

Furthermore, M _CGA represents the molecular weight of each chlorogenic acid, and each value is as follows.
_M3-CQA =354.31,
_M4-CQA =354.31,
_M5-CQA =354.31,
_M3-FQA =368.34,
_M4-FQA =368.34,
_M5-FQA =368.34,
_M3,4-diCQA =516.45,
_M3,5-diCQA =516.45,
_M4,5-diCQA =516.45

The measurement results of the amount of chlorogenic acids are shown in Table 7 (the standard amount of chlorogenic acids is shown as "100") (average of N=2). Example 5 had a chlorogenic acid amount 13.6% higher than Reference Example 5 (standard), confirming that the amount of chlorogenic acids could be increased by using a hydrogen burner compared to a natural gas burner. The L value was measured using the same method as above.

(Example 6: Increase in trigonelline)
(conditions)
Coffee beans: 5kg
Roasting time: 16 minutes Heat source: Hydrogen 0.1MPa
Example 6: 100% hydrogen
Comparative Example 6: 100% natural gas
Reference Example 6: 100% natural gas (standard roast)
Supply pressure: 10 kPa

Figure 9 shows an example of a product temperature curve during roasting. Example 6 is shown as a square plot line, Reference Example 6 as a circle plot line, and Comparative Example 6 as a triangular plot line. Reference Example 6 is a standard roasting temperature curve. The product temperature curve of Example 6 was set as a temperature rise curve with one inflection point in the later stage of roasting after the minimum value of the downward convexity in the middle stage of roasting, and decomposition of trigonelline was suppressed. The roasting profile of Comparative Example 6 was set to be close to the product temperature curve of Example 6, but a product temperature curve like that of Example 6 could not be realized.

(Trigoneline)
The amount of trigonelline was measured for each of Example 6 (hydrogen only combustion), Reference Example 6 (standard), and Comparative Example 6 (natural gas).
The method for obtaining the extract is as follows.
Extraction method: Paper drip method Extraction conditions: 20 g of coffee powder, 320 g of hot water poured, 20 seconds of steeping time The obtained extract was cooled to room temperature (20°C) and the amount of trigonelline was measured using high performance liquid chromatography under the following analytical conditions.
Column: CAPCELL PAK C18 AQ (particle size: 3 μm, inner diameter: 4.6 mm, length: 250 mm)
Column oven temperature: 35°C
Mobile phase: Solution A: 0.005 mol/L perchloric acid-containing water; Solution B: acetonitrile; Flow rate: 0.5 mL/min
Sample injection volume: 10 μL
Detection wavelength: 264 nm
Gradient conditions: shown in Table 8.

The amount of trigonelline is calculated from the measured area value of trigonelline using a calibration curve prepared using the trigonelline standard solution as a standard substance. The trigonelline standard solution is prepared by dissolving 253.2 mg of the standard trigonelline hydrochloride (Sigma) in ultrapure water to obtain 200 mg of trigonelline calculated by molecular weight conversion according to (Formula 2), and diluting the solution to 200 mL to obtain the trigonelline standard solution (100 mg/100 mL).
(Formula 2):
Amount of trigonelline (mg)=amount of trigonelline hydrochloride (mg)×(M _T )/(M _THC )
*M _T and M _THC represent the molecular weights of trigonelline and trigonelline hydrochloride, respectively, and their molecular weights are as follows:
M _T = 137.14
M _THC =173.60

The results of measuring the amount of trigonelline are shown in Table 9 (the standard amount of trigonelline is shown as "100") (average of N=2). Example 6 had a 13.2% higher amount of trigonelline than Reference Example 6 (standard), confirming that the amount of trigonelline could be increased by using a hydrogen burner compared to a natural gas burner. The L value was measured using the same method as above.

(method)
The coffee bean roasting method is a method for roasting coffee beans using hot air generated by an adjustable hydrogen-mixed combustion burner with a turndown ratio of 1:10 or more.
The coffee bean roasting and manufacturing method includes a control step of controlling the hydrogen-mixed combustion burner in accordance with a roasting profile of the coffee beans.
The control step may include feedback-controlling the hydrogen-mixed combustion burner so that a measured temperature (PV_t) measured by a temperature measuring device corresponds to a roasting profile of the coffee beans.
The control step may control the combustion power (heat power) (control the mixed-fuel ratio) by adjusting the valve opening of one or more valves selected from the group consisting of a valve provided in the hydrogen piping, a valve provided in the oxidizer piping, and a valve provided in the hydrocarbon fuel.
The control step may control the amount of circulated waste gas by adjusting the drive of a suction pump provided in the circulation pipe and the opening degree of a valve provided in the circulation pipe.

1 Coffee bean roasting device 10 Hydrogen mixed combustion burner 20 Roaster 30 Control device 31 Storage device 40 Temperature measuring device

Claims (8)

A hydrogen co-fuel burner capable of adjusting hydrogen and hydrocarbon fuel so that the turndown ratio is 1:10 or more;
A roaster that uses the hot air generated by the hydrogen-mixed combustion burner as a heat source for roasting;
A control device that controls the hydrogen-mixed combustion burner in accordance with a roasting profile of coffee beans;
A temperature measuring device is provided for measuring the temperature of the hot air generated by the hydrogen-mixed combustion burner,
The control device includes:
and controlling the hydrogen-mixed combustion burner so that the measured temperature measured by the temperature measuring device corresponds to a roasting profile of the coffee beans.
Coffee bean roasting equipment. The hydrogen-mixed combustion burner is
A burner body,
A burner tip portion,
a hydrogen supply nozzle disposed inside the burner body and having a nozzle tip with a circular cross section for supplying hydrogen;
an oxidizer supply nozzle having a ring-shaped cross section, which is disposed inside the burner body and provided outside the hydrogen supply nozzle, and which supplies an oxidizer;
a fuel supply nozzle having a ring-shaped cross section, which is disposed inside the burner body and provided outside the oxidizer supply nozzle, and which supplies a hydrocarbon-based fuel;
A hydrogen source having a predetermined pressure, a hydrogen pipe, and a valve provided on the hydrogen pipe;
An oxidant source having a predetermined pressure, an oxidant pipe, and a valve provided in the oxidant pipe;
A hydrocarbon fuel source having a predetermined pressure, a hydrocarbon fuel pipe, and a valve provided in the hydrocarbon fuel pipe;
Equipped with
The control device includes:
The combustion power is controlled by adjusting the valve opening degree of one or more of the valves provided in the hydrogen pipe, the valve provided in the oxidizer pipe, and the valve provided in the hydrocarbon fuel pipe.
2. The coffee bean roasting apparatus according to claim 1. The hydrogen-mixed combustion burner is
a circulation pipe for circulating hot air from a tip of the burner to the oxidizer pipe, a suction pump provided in the circulation pipe, and a valve provided in the circulation pipe;
Equipped with
The control device includes:
The amount of hot air circulated is controlled by adjusting the driving of a suction pump provided in the circulation pipe and the valve opening degree of a valve provided in the circulation pipe.
3. The coffee bean roasting apparatus according to claim 2. The roasting profile of the coffee beans includes a state in which the combustion power level of the hydrogen-mixed combustion burner is set lower than that of a burner using only a hydrocarbon fuel with a turndown ratio of less than 1:10.
4. A coffee bean roasting apparatus according to claim 1 . The roasting profile of the coffee beans is set to provide a product temperature curve during roasting that can achieve improved taste, improved aroma, and/or enhanced health components such as chlorogenic acids or trigonelline, as compared to roasting using a burner with a turndown ratio of less than 1:10 using only a hydrocarbon fuel.
5. The coffee bean roasting apparatus according to claim 4. A method for roasting coffee beans by using hot air generated by a hydrogen-mixed combustion burner, comprising:
A control step of controlling an adjustable hydrogen-mixed burner capable of burning hydrogen and a hydrocarbon-based fuel in accordance with a roasting profile of coffee beans so that a turndown ratio is 1:10 or more;
The control step includes:
controlling a hydrogen-mixed combustion burner so that the temperature of the hot air measured by the temperature measuring device corresponds to a roasting profile of the coffee beans;
The roasting profile of the coffee beans includes a state in which the combustion power level of the hydrogen-mixed combustion burner is set lower than that of a burner using only a hydrocarbon fuel with a turndown ratio of less than 1:10.
Coffee bean roasting production method. The roasting profile of the coffee beans is set to provide a product temperature curve during roasting that can achieve improved taste, improved aroma, and/or enhanced health components such as chlorogenic acids or trigonelline, as compared with roasting using a burner with a turndown ratio of less than 1:10 using only the hydrocarbon fuel.
The method for roasting and producing coffee beans according to claim 6. The control step includes:
feedback-controlling the hydrogen-mixed combustion burner so that a measured temperature (PV_t) measured by a temperature measuring device corresponds to a roasting profile of the coffee beans;
The combustion power (heat power) is controlled by adjusting the valve opening of one or more valves among a valve provided in a hydrogen pipe, a valve provided in an oxidizer pipe, and a valve provided in a hydrocarbon-based fuel pipe, and/or
The amount of waste gas circulated is controlled by adjusting the operation of a suction pump provided in the circulation pipe and the opening degree of a valve provided in the circulation pipe.
The method for roasting and producing coffee beans according to claim 6 .