JP7028626B2 - How to make roasted coffee beans - Google Patents

Description

The present invention relates to a method for producing roasted coffee beans.

Various materials have been proposed as materials having a bioactive function, and among them, polyphenols have been proposed as materials having a bioactive function such as an antioxidant effect, a blood pressure lowering effect, and a liver function improving effect. It has been reported that chlorogenic acids, which are one of the polyphenols, have a high blood pressure lowering effect. Raw coffee beans are a material containing a large amount of chlorogenic acids. Since raw coffee beans have a high water content, they are not only difficult to crush, but also a considerable number of bacteria survive, and because they have a unique raw bean odor, roasted coffee beans are suitable from the viewpoint of processability, antibacterial properties, and flavor. Generally preferred.

In the conventional roasting method of green coffee beans, heating the green coffee beans at a high temperature has been the mainstream. For example, in the embodiment of Patent Document 1, green coffee beans are roasted to a final temperature of 230 ° C.

Japanese Patent Application Laid-Open No. 2003-289805

When roasted by a method as described in the above patent document, the water content in beans and the survival number of bacteria are reduced, but chlorogenic acids are decomposed and the content of chlorogenic acids is inevitably reduced. On the other hand, if the roasting conditions are relaxed, the decrease due to the decomposition of chlorogenic acids can be suppressed, but the water content and the survival number of bacteria are insufficiently reduced. As described above, there is a trade-off relationship between the reduction in water content and the survival number of bacteria and the suppression of decomposition of chlorogenic acids, and it is difficult to achieve both.
The subject of the present invention is to achieve both reduction of water content and survival number of bacteria and suppression of decomposition of chlorogenic acids, and since the amount of chlorogenic acids is not maintained, roasted coffee beans with reduced water content and survival number of bacteria are achieved. Is to provide a manufacturing method for.

As a result of various studies, the present inventors focused on the temperature of roasted coffee beans during roasting, and based on the temperature of roasted coffee beans during roasting, raw coffee under the condition of satisfying a specific cumulative profile over time. By roasting beans, it is possible to achieve both a reduction in water content and survival of bacteria and suppression of decomposition of chlorogenic acids, and roasted coffee with reduced water content and survival of bacteria while maintaining the amount of chlorogenic acids. I found that beans can be obtained.

That is, the present invention is a method for producing roasted coffee beans, which comprises a step of roasting green coffee beans in a roasting apparatus, in which the roasting step is Ss at the start time of roasting and Sf at the end time of roasting. A method for producing roasted coffee beans that satisfies the following conditions (1) and (2) when the temperature of the coffee beans is Ts (° C.) from Ss at the start of roasting to s (min). It is to provide.

According to the present invention, roasted coffee beans containing abundant chlorogenic acids and having a reduced water content and bacterial survival can be achieved at the same time as reducing the water content and the survival number of bacteria. Can be manufactured with a simple operation.

In the production method of the present invention, first, raw coffee beans are housed in a roasting apparatus.
(Raw coffee beans)
The bean type of the green coffee beans may be, for example, any of Arabica, Robusta, Coffea liberica and Arabsta. The production area of coffee beans is not particularly limited, and examples thereof include Brazil, Colombia, Tanzania, Mocha, Kilimanjaro, Mandelin, Blue Mountain, Guatemala, and Vietnam. As the raw coffee beans, one kind or two or more kinds can be used. When two or more kinds of raw coffee beans are used, coffee beans having different bean seeds and production areas can be appropriately selected and used in any combination.

Further, the green coffee beans may be decaffeinated. As the decaffeination treatment, a known method can be adopted, and examples thereof include a water method, a supercritical carbon dioxide extraction method, and an organic solvent extraction method. Among them, the water method and the supercritical carbon dioxide extraction method are preferable from the viewpoint of safety and flavor.

The particle size of the green coffee beans may be uncrushed (whole grain), crushed product, or a mixture thereof, but uncrushed (whole grain) is preferable from the viewpoint of ease of roasting degree control. The method for crushing green coffee beans is not particularly limited, and known methods and devices can be used. For example, a crushing device such as a cutter mill, a hammer mill, a jet mill, an impact mill, a willley crusher, a roll grinder, Cutter mills such as flat cutters, conical cutters, and grade grinders can be used. The particle size of the ground coffee beans may be coarsely ground, medium ground or finely ground.

(Roasting equipment)
The roasting apparatus is not particularly limited, and for example, an apparatus such as a roasted bean stationary type, a roasted bean transfer type, and a roasted bean stirring type can be used. More specifically, for example, a shelf type dryer, a conveyor type dryer, a rotary drum type dryer, a rotary V type dryer and the like can be mentioned. Examples of the heating method include a direct flame type, a hot air type, a semi-hot air type, a far infrared type, an infrared type, a microwave type, a superheated steam type and the like.

(Roasting process)
Next, the roasting step is carried out.
In the roasting step, Ss at the start of roasting and Sf (min) at the end of roasting are controlled, and the temperature Ts (° C.) of coffee beans is measured after s (min) has elapsed from Ss at the start of roasting. Here, in the present specification, the “ss at the start of roasting” means the time when the green coffee beans are stored in the roasting apparatus. The "sf at the end of roasting" is the time when the coffee beans are taken out from the roasting device after being heated in the roasting device. The temperature Ts of coffee beans from Ss at the start of roasting to s (min) can be measured by inserting a thermocouple into the roasting apparatus, for example. If the temperature of the coffee beans in the roasting device can be measured, the method is not limited to this method.

The temperature Ts of coffee beans is usually measured over time from Ss at the start of roasting to Sf at the end of roasting so as to observe a temporal temperature profile, but if a temporal temperature profile can be created, it is measured at regular intervals. You may measure it. Then, when the horizontal axis is the elapsed time from the roasting start time Ss and the vertical axis is the temperature of the coffee beans at that elapsed time, the area calculated by multiplying the elapsed time s and the bean temperature Ts is integrated. And quantify. Specifically, it is obtained by the time-dependent integration profile represented by the following formula (i).

The value calculated by the above formula (i) is 1500 or more, but from the viewpoint of reducing the water content and the survival number of bacteria, 1600 or more is preferable, 1700 or more is more preferable, 1800 or more is further preferable, and 1900 or more. Is particularly preferable. The upper limit of the value calculated by the formula (i) is not particularly limited as long as the formula (ii) described later is satisfied at the same time, but from the viewpoint of maintaining the amount of chlorogenic acids, 3600 or less is preferable, and 3000 or less is more preferable. 2600 or less is more preferable, and 2200 or less is particularly preferable. The range of values calculated by the formula (i) is preferably 1500 or more and 3600 or less, more preferably 1600 or more and 3000 or less, still more preferably 1700 or more and 2600 or less, still more preferably 1800 or more and 2600 or less, and particularly still more preferable. Is 1900 or more and 2200 or less.

Further, as the amount of heating given to the coffee beans in the roasting step, the temperature Ts of the coffee beans from the time when the roasting is started Ss to the time when s (min) has elapsed is measured over time to calculate the F0 value, which is calculated by the following formula. Calculated by integrating with the temporal integration profile represented by (ii). The "F0 value" is a value obtained by converting the sterilization heating amount for each bean temperature into the length of the sterilization time at 121 ° C.

The value calculated by the above formula (ii) is 7,000 or more and 35,000,000 or less, but from the viewpoint of reducing the water content and the survival number of bacteria, 10,000 or more is preferable, 20,000 or more is more preferable, and 40,000 or more is further preferable. 60,000 or more is further preferable, 80,000 or more is particularly preferable, and from the viewpoint of maintaining the amount of chlorogenic acids, 3,000,000 or less is more preferable, 2000000 or less is more preferable, 1,000,000 or less is further preferable, and 400,000 or less is particularly preferable. The range of values calculated by the formula (ii) is preferably 10,000 or more and 3,000,000 or less, more preferably 20,000 or more and 2000000 or less, still more preferably 40,000 or more and 1,000,000 or less, still more preferably 60,000 or more and 400,000 or less, and particularly still more preferable. Is 80,000 or more and 400,000 or less.

The roasting time Sf-Ss is not particularly limited as long as the above formulas (i) and (ii) are satisfied, but from the viewpoint of maintaining the amount of chlorogenic acids, 25 minutes or less is preferable, 24 minutes or less is more preferable, and 23 minutes or less. Is more preferable, 22 minutes or less is further preferable, and 21 minutes or less is particularly preferable. Further, from the viewpoint of reducing the water content and the survival number of bacteria, 5 minutes or more is preferable, 9 minutes or more is more preferable, 11 minutes or more is further preferable, and 13 minutes or more is particularly preferable. The range of the roasting time is preferably 5 minutes or more and 25 minutes or less, more preferably 5 minutes or more and 24 minutes or less, further preferably 9 minutes or more and 23 minutes or less, still more preferably 11 minutes or more and 22 minutes or less, and particularly particularly. It is preferably 13 minutes or more and 21 minutes or less.

The roasting device may be heated so as to satisfy the above formulas (i) and (ii). For example, the heating temperature of the roasting apparatus is usually preferably 300 to 550 ° C, preferably 350 to 550 ° C, and more preferably 400 to 500 ° C. Further, the roasting apparatus may raise the temperature after accommodating the green coffee beans, but from the viewpoint of production efficiency, it is preferable to raise the temperature of the roasting apparatus in advance. The preheating temperature of the roasting apparatus can be set to the same temperature as or different from the heating temperature at the time of roasting. For example, the preheating temperature at the time of roasting is preferably 100 to 300 ° C., more preferably 100 ° C. Can be set to a low temperature of about 150 to 250 ° C.

Further, it is preferable that the roasting step is performed by controlling the water removal rate in the green coffee beans to be 0.7 kg / min or more. As a result, uneven roasting of coffee beans is reduced, and variations in the amount of chlorogenic acids in roasted coffee beans can be suppressed. From the viewpoint of further suppressing uneven roasting, the water removal rate is preferably 0.8 kg / min or more, more preferably 0.9 kg / min or more, still more preferably 1.0 kg / min or more. The upper limit of the water removal rate is not particularly limited, but from the viewpoint of production stability, 2.0 kg / min or less is preferable, 1.9 kg / min or less is more preferable, and 1.8 kg / min or less is further preferable. 1.7 kg / min or less is particularly preferable. The range of the water removal rate is preferably 0.7 to 2.0 kg / min, more preferably 0.8 to 1.9 kg / min, still more preferably 0.9 to 1.8 kg / min, and even more preferably 0.9 to 1.8 kg / min. It is 1.0 to 1.7 kg / min. The water removal rate can be measured according to the method described in Examples described later.

The atmosphere in the roasting apparatus may be under air or under an inert gas. Examples of the inert gas include nitrogen, argon, helium, carbon dioxide and the like.
The pressure condition in the roasting apparatus may be atmospheric pressure, reduced pressure, or pressurization, but is usually atmospheric pressure.

In this way, the roasted coffee beans of the present invention can be produced, and the obtained roasted coffee beans can have the following characteristics.
(I) The content of chlorogenic acids in roasted coffee beans is usually 4% by mass or more, preferably 5% by mass or more, and more preferably 6% by mass or more. The upper limit of the content of the chlorogenic acids is not particularly limited, but is usually 10% by mass or less, preferably 8% by mass or less. Here, the "chlorogenic acids" in the present specification are monocafe oil quinic acid of 3-cafe oil quinic acid, 4-cafe oil quinic acid and 5-cafe oil quinic acid, and 3-ferloyl quinic acid, 4 -A generic term for ferroyl quinic acid and monoferroyl quinic acid of 5-ferloyl quinic acid, and the content of chlorogenic acids is defined based on the total amount of the above 6 types. The content of chlorogenic acids in roasted coffee beans can be measured according to the method described in Examples described later.
(Ii) The water content of the roasted coffee beans is 4% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less, and further preferably 1% by mass or less. The lower limit of the water content is not particularly limited and may be 0% by mass. The water content of roasted coffee beans can be measured according to the method described in Examples described later.
(Iii) The number of bacteria per 1 g of roasted coffee beans is usually 3000 or less, preferably 300 or less, and more preferably 30 or less. Examples of bacteria in roasted coffee beans include A. niger , A. tubingensis , and A. carbonarius . In addition, the number of bacteria in roasted coffee beans can be measured according to the method described in Examples described later.
(Iv) The L value of roasted coffee beans is usually 35 to 60, preferably 38 to 58, and more preferably 40 to 55. Here, in the present specification, the "L value" is obtained by measuring the brightness of roasted coffee beans with a color difference meter, where black is L value 0 and white is L value 100.
(V) The standard deviation of the content of chlorogenic acids in roasted coffee beans is preferably 0.15 or less, more preferably 0.1 or less, still more preferably 0.08 or less. The standard deviation shall be measured according to the method described in the examples below.

1. 1. Analysis of roasted coffee beans Roasted coffee beans were crushed, and 0.5 g of crushed roasted coffee beans was dissolved in 1 L of ion-exchanged water with extraction water (1 g of phosphoric acid and 0.03 g of 1-hydroxy 1,1-dysphonic acid). 80 g of the liquid) was added, and immersion extraction was performed for 10 minutes while keeping the temperature between 95 and 99 ° C., and the supernatant was collected to obtain a coffee extract. Based on the obtained coffee extract, the content of chlorogenic acids in roasted coffee beans was analyzed.

(1) Analysis of chlorogenic acids HPLC was used as the analytical instrument. The model numbers of the constituent units of the device are as follows.
-UV-VIS detector: L-2420 (Hitachi High-Technologies Corporation)
・ Column oven: L-2300 (Hitachi High-Technologies Corporation)
・ Pump: L-2130 (Hitachi High-Technologies Corporation)
・ Autosampler: L-2200 (Hitachi High-Technologies Corporation)
-Column: Cadenza CD-C18, inner diameter 4.6 mm x length 150 mm, particle diameter 3 μm (Intact Co., Ltd.)

The analysis conditions are as follows.
-Sample injection volume: 10 μL
・ Flow rate: 1.0 mL / min
・ UV-VIS detector set wavelength: 325nm
・ Column oven set temperature: 35 ° C
Eluent A: A solution obtained by diluting acetonitrile with water to a concentration of 5 (V / V)% of acetonitrile, such as 0.05 M acetic acid, 0.1 mM 1-hydroxyethane-1,1-diphosphonic acid, and Solution / eluent B containing 10 mM sodium acetate B: acetonitrile

Concentration gradient condition (% by volume)
Time Eluent A Eluent B
0.0 minutes 100% 0%
10.0 minutes 100% 0%
15.0 minutes 95% 5%
20.0 minutes 95% 5%
22.0 minutes 92% 8%
50.0 minutes 92% 8%
52.0 minutes 10% 90%
60.0 minutes 10% 90%
60.1 minutes 100% 0%
70.0 minutes 100% 0%

In HPLC, 1 g of the sample was finely weighed, and the sample was dispensed to 10 mL with eluent A, filtered through a membrane filter (GL chromatodisc 25A, pore size 0.45 μm, GL Sciences Co., Ltd.), and then subjected to analysis.
Retention time of chlorogenic acids (unit: minutes) 6 kinds of chlorogenic acids ・ Monocafe oil quinic acid: 5.3, 8.8, 11.6, total 3 points ・ Monoferloylquinic acid: 13.0, 19. A total of 3 points of 9, 21.0 From the area values of the 6 kinds of chlorogenic acids obtained here, 5-cafe oil quinic acid was used as a standard substance, and the mass% was determined.

(2) Bacterial count analysis We requested the Japan Food Research Laboratories to analyze the bacterial count. The roasted coffee beans were treated with a stomacher to prepare a diluted solution, which was used for analysis. The analysis was performed by the standard agar plate culture method.

2. 2. Analysis of moisture content The roasted coffee beans after cooling were kept in an electric furnace at 100 ° C. for 6 hours and dried. From the mass of roasted coffee beans before and after drying, the water content was calculated from the following formula (iii).

[In the formula (iii), A indicates the mass (g) of the roasted coffee beans before drying, and B indicates the mass (g) of the roasted coffee beans after drying. ]

3. 3. Measurement of water removal rate in green coffee beans in the roasting process The water removal rate in green coffee beans in the roasting process was calculated from the following formula (iv).

[In formula (iv), C indicates the water content (%) of the green coffee beans before roasting, D indicates the water content (%) of the coffee beans after roasting, and E indicates the raw coffee before roasting. The mass (kg) of beans is shown, and F is the roasting time (min). ]

4. Measurement of standard deviation of chlorogenic acid After roasting, 100 g of roasted coffee beans were sampled from different locations in the roasting equipment at 20 points. The content of chlorogenic acids in roasted coffee beans was analyzed for each sample, and the standard deviation of the content of chlorogenic acids in roasted coffee beans was calculated among 20 points.

Example 1
A hot air roasting machine (manufactured by Probat) was used as the roasting device. The burner temperature was set to 450 ° C., and the apparatus was preheated until the temperature inside the tank reached 215 ° C. Then, 250 kg of uncrushed green coffee beans (Robusta coffee produced in Vietnam) was put into a roasting apparatus and roasted for 12 minutes. The product temperature during roasting was measured, and the integrated value was calculated based on the above formula (i) and the above formula (ii). Further, the obtained roasted coffee beans were analyzed for the content of chlorogenic acids, the water content and the number of bacteria, and the water removal rate was calculated based on the above (iv). The results are shown in Table 1.

Example 2
Roasting was carried out by the same operation as in Example 1 except that the roasting time was changed to that shown in Table 1. The product temperature during roasting was measured, and the integrated value was calculated based on the above formula (i) and the above formula (ii). Then, in the obtained roasted coffee beans, the content of chlorogenic acids, the water content and the number of bacteria were analyzed in the same manner as in Example 1, and the water removal rate was calculated. The results are also shown in Table 1.

Example 3
Roasting was carried out by the same operation as in Example 1 except that the roasting time was changed to that shown in Table 1. The product temperature during roasting was measured, and the integrated value was calculated based on the above formula (i) and the above formula (ii). Then, in the obtained roasted coffee beans, the content of chlorogenic acids, the water content and the number of bacteria were analyzed in the same manner as in Example 1, and the water removal rate was calculated. The results are also shown in Table 1.

Comparative Example 1
Roasting was carried out by the same operation as in Example 1 except that the roasting time was changed to that shown in Table 1. The product temperature during roasting was measured, and the integrated value was calculated based on the above formula (i) and the above formula (ii). Then, in the obtained roasted coffee beans, the content of chlorogenic acids, the water content and the number of bacteria were analyzed in the same manner as in Example 1, and the water removal rate was calculated. The results are also shown in Table 1.

Comparative Example 2
Roasting was carried out by the same operation as in Example 1 except that the burner temperature, the amount charged and the roasting time were changed as shown in Table 1. The product temperature during roasting was measured, and the integrated value was calculated based on the above formula (i) and the above formula (ii). Then, in the obtained roasted coffee beans, the content of chlorogenic acids, the water content and the number of bacteria were analyzed in the same manner as in Example 1, and the water removal rate was calculated. The results are also shown in Table 1.

Comparative Example 3
Roasting was carried out by the same operation as in Comparative Example 2 except that the roasting time was changed to that shown in Table 1. The product temperature during roasting was measured, and the integrated value was calculated based on the above formula (i) and the above formula (ii). Then, in the obtained roasted coffee beans, the content of chlorogenic acids, the water content and the number of bacteria were analyzed in the same manner as in Example 1, and the water removal rate was calculated. The results are also shown in Table 1.

Comparative Example 4
Roasting was carried out by the same operation as in Comparative Example 2 except that the roasting time was changed to that shown in Table 1. The product temperature during roasting was measured, and the integrated value was calculated based on the above formula (i) and the above formula (ii). Then, in the obtained roasted coffee beans, the content of chlorogenic acids, the water content and the number of bacteria were analyzed in the same manner as in Example 1, and the water removal rate was calculated. The results are also shown in Table 1.

From Table 1, by roasting green coffee beans under the conditions satisfying the above (1) and (2), the water content and the survival number of bacteria are both reduced, and the decomposition of chlorogenic acids is suppressed. It can be seen that roasted coffee beans with reduced water content and bacterial survival can be obtained because the acid content is not maintained.

Example 4
A hot air roasting machine (manufactured by Probat) was used as the roasting device. The burner temperature was 450 ° C., the damper closing degree was 60%, and the device was preheated until the temperature inside the tank reached 190 ° C. Then, 250 kg of uncrushed green coffee beans (Robusta coffee produced in Vietnam) was put into a roasting apparatus and roasted for 14.7 minutes. The product temperature during roasting was measured, and the integrated value was calculated based on the above formula (i) and the above formula (ii). Further, for the obtained roasted coffee beans, the content, water content and bacterial count of chlorogenic acids were analyzed in the same manner as in Example 1, and the water removal rate and the standard deviation of the chlorogenic acids of the 20-point sample were calculated. The results are shown in Table 2.

Example 5
Roasting was carried out in the same manner as in Example 4 except that the degree of damper closing and the roasting time were changed as shown in Table 2. The product temperature during roasting was measured, and the integrated value was calculated based on the above formula (i) and the above formula (ii). Then, in the obtained roasted coffee beans, the content, water content and bacterial count of chlorogenic acids were analyzed in the same manner as in Example 4, and the water removal rate and the standard deviation of the chlorogenic acids of the 20-point sample were calculated. The results are also shown in Table 2.

From Table 2, when roasting under the conditions satisfying the above (1) and (2), the coffee beans are roasted by controlling the water removal rate in the green coffee beans to be 0.7 kg / min or more. It can be seen that roasted coffee beans can be obtained with less variation in the amount of chlorogenic acids while reducing uneven roasting and containing abundant chlorogenic acids.

Claims (6)

A method for producing roasted coffee beans, which includes a step of roasting raw coffee beans in a roasting device.
When the roasting step is Ss at the start of roasting, Sf at the end of roasting, and Ts (° C.) is the temperature of coffee beans after s (min) has elapsed from Ss at the start of roasting, the following (1) ) And (2), a method for producing roasted coffee beans.

The method for producing roasted coffee beans according to claim 1, wherein the roasting step is further controlled so that the water removal rate in the green coffee beans is 0.7 kg / min or more. The method for producing roasted coffee beans according to claim 1 or 2, wherein the water content of the roasted coffee beans is 4% by mass or less. The method for producing roasted coffee beans according to any one of claims 1 to 3 , wherein the inequality shown in (2) is 10,000 or more and 2000,000 or less. The method for producing roasted coffee beans according to any one of claims 1 to 4 , wherein the roasting step further satisfies the condition of (3) below.
(3) Sf-Ss ≦ 25 The method for producing roasted coffee beans according to any one of claims 1 to 5 , wherein the content of chlorogenic acids in the roasted coffee beans is 5% by mass or more.