JP2015012866A - Method for producing roasted coffee bean - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a roasted coffee bean in which the amount of chlorogenic acid is made higher, and also, the amount of hydroxyhydroquinone is more reduced.SOLUTION: Provided is a method for producing a roasted coffee bean comprising the step of subjecting a raw coffee bean to heat treatment at below 200°C for 5 to 250 min in a vacuum with a vacuum degree of 7 kPa or lower to control the mass ratio between hydroxyhydroquinone (A) and chlorogenic acid (B) [(A)/(B)] in the roasted coffee bean to 55×10and the chlorogenic acid content in the roasted coffee bean to 2.8 to 8 mass%.

Description

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

  It has been reported that chlorogenic acids such as chlorogenic acid, caffeic acid and ferulic acid contained in foods and beverages such as coffee beverages show excellent physiological effects (Patent Documents 1 to 3).

  However, it has been found that when coffee beans are roasted, hydroxyhydroquinone is naturally generated, and this hydroxyhydroquinone inhibits the physiological action of chlorogenic acids (Patent Document 4). Therefore, in order to fully express the physiological effects of chlorogenic acids, it is effective to use roasted coffee beans having a high chlorogenic acid concentration and a low hydroxyhydroquinone concentration.

  Therefore, in order to reduce the amount of hydroxyhydroquinone in roasted coffee beans, for example, the coffee beans are subjected to aging treatment at a temperature of 40 to 150 ° C. and lower than the roasting temperature. A manufacturing method has been proposed (Patent Document 5).

JP 2002-363075 A JP 2002-22062 A JP 2002-53464 A JP 2006-204192 A JP 2008-48728 A

  According to the method described in Patent Document 5, it is possible to reduce the amount of hydroxyhydroquinone in roasted coffee beans from the amount normally contained. There is a need for roasted coffee beans that have a higher amount of acids and a lower amount of hydroxyhydroquinone.

  Accordingly, an object of the present invention is to provide a roasted coffee bean having a higher amount of chlorogenic acids and a reduced amount of hydroxyhydroquinone, and a method for producing the same. Another object of the present invention is to provide a coffee extract and soluble coffee obtained from the roasted coffee beans.

  As a result of various studies to solve the above-mentioned problems, the present inventors have surprisingly made the raw coffee beans heat-treated under a certain condition under vacuum, surprisingly, while leaving a larger amount of chlorogenic acids, It has been found that roasted coffee beans with significantly reduced hydroquinone content can be obtained.

That is, the present invention is roasted coffee beans having an L value of 20 to 40,
The mass ratio [(A) / (B)] of (A) hydroxyhydroquinone and (B) chlorogenic acids in the roasted coffee beans is 55 × 10 ⁻⁴ (−) or less, and in the roasted coffee beans A roasted coffee bean having a chlorogenic acid content of 2.8 to 8% by mass is provided.

The present invention is also a coffee extract obtained from roasted coffee beans having an L value of 20-40,
The mass ratio of the solid content in the coffee extract and the (A) hydroxyhydroquinone content [(A) hydroxyhydroquinone content / solid content] is 0.000001 to 0.0004 (−),
The mass ratio [(B) chlorogenic acid amount / solid content amount] of the solid content amount and the chlorogenic acid amount in the coffee extract is 0.04 to 0.3 (-), and (A) hydroxy in the coffee extract A coffee extract having a mass ratio [(A) / (B)] of hydroquinone and (B) chlorogenic acids of 55 × 10 ⁻⁴ (−) or less is provided.

  The present invention further provides soluble coffee obtained by spray drying or freeze drying the above coffee extract.

  The present invention further includes a first step of heat-treating green coffee beans under vacuum at a temperature of less than 200 ° C. for 5 to 250 minutes, or heat-treating green coffee beans under vacuum, and the first step. The present invention provides a method for producing roasted coffee beans, which includes a second step of heat-treating the obtained coffee beans under vacuum.

  According to the present invention, roasted coffee beans having a higher amount of chlorogenic acids and a reduced amount of hydroxyhydroquinone are provided. In addition, the coffee extract and soluble coffee obtained from the roasted coffee beans of the present invention are rich in chlorogenic acids, and the amount of hydroxyhydroquinone that inhibits the physiological action of chlorogenic acids is reduced. The effective content of chlorogenic acids can be further increased, and as a result, the physiological effect of chlorogenic acids can be sufficiently expected. Furthermore, according to the production method of the present invention, roasted coffee beans having a larger amount of chlorogenic acids and a reduced amount of hydroxyhydroquinone can be easily produced.

[Roasted coffee beans]
The L value of the roasted coffee beans of the present invention is 20 to 40, preferably 21 to 35, more preferably 23 to 33, and particularly preferably 25 to 30. Here, “L value” in this specification is a value obtained by measuring the brightness of roasted coffee beans with a color difference meter, with black as L value 0 and white as L value 100.

The roasted coffee beans of the present invention have a mass ratio [(A) / (B)] of (A) hydroxyhydroquinone and (B) chlorogenic acids in the roasted coffee beans of 55 × 10 ⁻⁴ (−) or less. However, from the viewpoint of physiological effect, it is preferably 50 × 10 ⁻⁴ (−) or less, more preferably 40 × 10 ⁻⁴ (−) or less, more preferably 30 × 10 ⁻⁴ (−) or less, and still more preferably. 20 × 10 ⁻⁴ (−) or less, particularly preferably 10 × 10 ⁻⁴ (−) or less. The lower limit is not particularly limited, and may be 0.
The content of (B) chlorogenic acids in the roasted coffee beans of the present invention is 2.8 to 8% by mass, preferably 2.9 to 7% by mass, particularly preferably 3 from the viewpoint of physiological effects. -6 mass%.
The mass ratio [(B ³ ) / (B)] of (B ³ ) dicaffeoylquinic acid and (B) chlorogenic acids in the roasted coffee beans is preferably 5 × 10 ⁻² to 15 × 10 6. ⁻² (−), more preferably 6 × 10 ^{−2 to} 13 × 10 ⁻² (−), still more preferably 7 × 10 ^{−2 to} 11 × 10 ⁻² (−), and particularly preferably 8 × 10 ^−2. 10 × 10 ⁻² (−). Thereby, the physiological effect by (B) chlorogenic acids can fully be expected.

Here, in this specification, “(B) chlorogenic acids” means (B ¹ ) monocaffeoylquinic acid of 3-caffeoylquinic acid, 4-caffeoylquinic acid and 5-caffeoylquinic acid, and 3 -(B ² ) monoferlaquinic acid of 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid and 4,5-dicaffe Oil quinic acid is a general term that includes (B ³ ) dicaffeoylquinic acid, and (B) the amount of chlorogenic acids is defined based on the total amount of the above nine types. On the other hand, the amount of (B ³ ) dicaffeoylquinic acid is defined based on the total amount of the three kinds of dicaffeoylquinic acid.

  In addition, “(B) chlorogenic acid content in roasted coffee beans” and “hydroxyhydroquinone content in roasted coffee beans” in this specification are (B) in the coffee extract obtained from roasted coffee beans. Based on the amount of chlorogenic acids and the amount of hydroxyhydroquinone, it was determined by the following formulas (1) and (2). .

(B) Chlorogenic acids in roasted coffee beans [% by mass] = (B) Chlorogenic acids in coffee extract [mg / kg] × Coffee extract mass [kg] / Roasted coffee bean mass [kg] ) × 100 (1)
Amount of hydroxyhydroquinone in roasted coffee beans [% by mass] = Amount of hydroxyhydroquinone in coffee extract [mg / kg] × Mass of coffee extract [kg] / Mass of roasted coffee beans [kg] × 100 2)

  The extraction conditions for the coffee extract are as follows. If necessary, roasted coffee beans are pulverized, and those having a particle size range between JIS standard sieve 42 mesh and 80 mesh are collected. Next, 10 parts by mass of hot water at 98 ° C. is added to 1 part by mass of the roasted coffee beans collected, and stirring with a stirrer (100 rpm) is performed for 10 minutes while maintaining the liquid temperature at 95 ° C. or higher in a liquid nitrogen atmosphere. Do. Next, it is filtered with a coffee paper filter to obtain a coffee extract.

[Method of manufacturing roasted coffee beans]
Roasted coffee beans having the above properties can be produced by the following method.

[Preparation process]
First, prepare raw coffee beans.
The kind of green coffee bean to be used is not particularly limited, and examples thereof include Arabica, Robusta, and Revelica. Examples of coffee bean varieties include Brazil, Colombia, Tanzania, Mocha, Kilimangelo, Mandelin, Blue Mountain, Guatemala, and the like. One kind of these coffee beans may be used, or a plurality of kinds may be blended.

  The green coffee beans may be crushed or unground. Although the magnitude | size of the grind | pulverized green coffee beans can be selected suitably, it is 30-100 mesh, for example.

[Heat treatment process]
After preparing the green coffee beans, the green coffee beans are heat-treated at a temperature below 200 ° C. for 5 to 250 minutes under vacuum. Thereby, a green coffee bean can be roasted, removing hydroxyhydroquinone efficiently, without impairing the amount of chlorogenic acids greatly.

Examples of the method for heat-treating green coffee beans under vacuum include the following method i) or ii).
i) A method in which green coffee beans are put into an apparatus and heated to a predetermined temperature while reducing the pressure to a predetermined degree of vacuum.
ii) A method in which green coffee beans are put into a device preheated to a predetermined temperature, and the pressure is reduced to a predetermined degree of vacuum while maintaining the predetermined temperature.

Although heating temperature is less than 200 degreeC, Preferably it is 90-190 degreeC, More preferably, it is 100-180 degreeC, More preferably, it is 110-170 degreeC, Most preferably, it is 120-160 degreeC.
The degree of vacuum is preferably 7 kPa or less, more preferably 6 kPa or less, still more preferably 5 kPa or less, particularly preferably 4 kPa or less, and even more preferably 3 kPa or less. In addition, it is preferable that the minimum of a vacuum degree is 0.13 kPa from a production efficiency and an economical viewpoint.
The heating time is preferably 5 to 250 minutes, preferably 10 to 150 minutes, more preferably 15 to 90 minutes, and particularly preferably 20 to 60 minutes.

  The apparatus to be used is not particularly limited as long as the pressure can be adjusted freely and can be heated to the above-mentioned predetermined temperature. Is done. Specifically, a shelf dryer, a conveyor dryer, a rotary drum dryer, a rotary V dryer, or the like can be used. Examples of the heating source include hot air, far infrared rays, infrared rays, microwaves, and superheated steam.

  The roasted coffee beans after the heat treatment can be gradually cooled to 0 to 100 ° C., preferably 10 to 60 ° C., but are preferably cooled to the above temperature within 30 minutes from the viewpoint of flavor. In cooling, the vacuum state may be returned to atmospheric pressure as it is after the apparatus is stopped, or may be returned to atmospheric pressure while being replaced with an inert gas such as nitrogen.

  Moreover, in this invention, it roasts by the process including the 1st process which heat-processes green coffee beans under a vacuum, and the 2nd process which heat-processes the coffee beans obtained by the 1st process under a vacuum. Coffee beans may be produced.

(First step)
The heat treatment in the first step may employ the same conditions as described above, but can be performed at a lower temperature and in a shorter time than the above manufacturing method.
Specifically, the degree of vacuum is preferably 7 kPa or less, more preferably 6 kPa or less, still more preferably 5 kPa or less, particularly preferably 4 kPa or less, and even more preferably 3 kPa or less. In addition, it is preferable that the minimum of a vacuum degree is 0.13 kPa from a production efficiency and an economical viewpoint.
The heating temperature is preferably 80 to 180 ° C, more preferably 90 to 160 ° C, particularly preferably 100 to 150 ° C, and the heating time is preferably 3 to 60 minutes, more preferably 5 to 30 minutes, Especially preferably, it is 5 to 20 minutes.
Thereby, while roasting fresh coffee beans, hydroxyhydroquinone can be efficiently removed while leaving more chlorogenic acids.
After the first step, the obtained coffee beans are preferably cooled by the same operation as described above.

(Second step)
The heat treatment in the second step may employ the same conditions as in the first step, but it is preferable to use the following treatment conditions as the heat treatment in the second step.
The degree of vacuum is preferably 5 kPa or less, more preferably 4 kPa or less, still more preferably 3 kPa or less, particularly preferably 2 kPa or less, and even more preferably 1 kPa or less. In addition, it is preferable that the minimum of a vacuum degree is 0.13 Pa from production efficiency and an economical viewpoint. The degree of vacuum in the second step is preferably higher than that in the first step from the viewpoint of the removal efficiency of hydroxyhydroquinone.
The heating temperature is preferably 100 to 180 ° C, more preferably 110 to 180 ° C, still more preferably 120 to 175 ° C, and particularly preferably 130 to 170 ° C. The heating time is preferably 3 to 60 minutes, More preferably, it is 5 to 50 minutes, and particularly preferably 8 to 40 minutes. Thereby, the amount of hydroxyhydroquinone can be further reduced while leaving a larger amount of (B) chlorogenic acids in the roasted coffee beans.
Note that after the second step, the roasted coffee beans may be cooled by the same operation as that after the first step. Further, after the second step, the same heat treatment as in the second step can be performed 1 to 3 times, preferably 1 to 2 times. The processing conditions at that time are as described above.

  In this way, the roasted coffee beans of the present invention can be obtained.

[Coffee extract]
The coffee extract of the present invention can be obtained from the roasted coffee beans having an L value of 20 to 40. The “coffee extract” referred to here is one in which roasted coffee beans are used in an amount of 1 g or more, preferably 2.5 g or more, particularly preferably 5 g or more in terms of green beans per 100 g of the coffee extract.
The coffee extract may be obtained by extracting roasted coffee beans as they are, or may be obtained by extracting roasted coffee beans after drying.
The degree of pulverization of roasted coffee beans used for extraction can be selected as appropriate. For example, ultrafine grinding (0.250-0.500 mm), fine grinding (0.300-0.650 mm), medium fineness Grinding (0.530-1.000mm), Medium grinding (0.650-1.500mm), Medium coarse grinding, Coarse grinding (0.850-2.100mm), Very coarse grinding (1.000-2.500mm) And cut products having an average particle diameter of about 3 mm, 5 mm, or 10 mm.

As an extraction method, for example, a known method such as a boiling method, an espresso method, a siphon method, a drip method (paper, flannel, etc.) can be adopted, and batch extraction, semi-batch extraction, or continuous extraction is possible. It may be. From the viewpoint of flavor, the extraction time of batch extraction or semi-batch extraction, that is, the contact time or residence time with roasted coffee beans is preferably 10 seconds to 120 minutes, particularly preferably 30 seconds to 30 minutes.
As the extractor, known ones such as paper drip, non-woven drip, siphon, nell drip, espresso machine, coffee machine, percolator, coffee press, ibrick, water drip, boiling, kneader, drip extractor, column extractor, etc. are used. it can. Further, the extractor may be provided with a heating or cooling means such as a jacket through which hot water, steam or cold water can be passed, or an electric heater.

Examples of the extraction solvent include water, aqueous alcohol solution, milk, carbonated water and the like. Among these, water is preferable from the viewpoint of flavor. The pH of the extraction solvent (20 ° C., the same applies hereinafter) is usually 4 to 10, but 5 to 7 is preferable from the viewpoint of flavor. In addition, you may adjust pH by containing pH adjusters, such as sodium bicarbonate, sodium hydrogencarbonate, L-ascorbic acid, sodium L-alcorbate, in an extraction solvent, for example.
Although the temperature of an extraction solvent can be suitably selected according to the kind of extraction solvent, Preferably it is 0-100 degreeC, More preferably, it is 10-100 degreeC, Most preferably, it is 80-100 degreeC.
The amount of the extraction solvent is preferably 0.5 to 50 parts by mass, particularly preferably 0.5 to 10 parts by mass with respect to 1 part by mass of roasted coffee beans.

  The solid content in the coffee extract is preferably 0.1% by mass or more, more preferably 0.5 to 30% by mass, still more preferably 1 to 20% by mass, and particularly preferably 2 from the viewpoint of flavor stability. -10 mass%. In the present specification, the “solid content (% by mass) in the coffee extract” is the value of “Measurement of Brix” described in the examples below.

The coffee extract of the present invention can have the following characteristics i) to iv).
i) The mass ratio of the solid content in the coffee extract to the (A) hydroxyhydroquinone content [(A) hydroxyhydroquinone content (mass%) / solid content (mass%)] is 0.000001 to 0.0004 ( Although it is-), from a viewpoint of a physiological effect, Preferably it is 0.000005-0.0003 (-), Most preferably, it is 0.00001-0.0002 (-).
ii) Mass ratio of solid content in coffee extract to (B) chlorogenic acids [(B) chlorogenic acids (mass%) / solid contents (mass%)] is 0.04 to 0.3 (- However, from the viewpoint of physiological effects, it is preferably 0.08 to 0.25, particularly preferably 0.1 to 0.2.
iii) The mass ratio [(A) (mass%) / (B) (mass%)] of (A) hydroxyhydroquinone and (B) chlorogenic acids in the coffee extract is 55 × 10 ⁻⁴ (−) or less. However, from the viewpoint of physiological effects, it is preferably 50 × 10 ⁻⁴ (−) or less, more preferably 40 × 10 ⁻⁴ (−) or less, still more preferably 20 × 10 ⁻⁴ (−) or less, particularly preferably. Is 10 × 10 ⁻⁴ (−) or less. The lower limit is not particularly limited, and may be 0.
iv) The mass ratio [(B ³ ) (mass%) / (B) (mass%)] of (B ³ ) dicaffeoylquinic acid and (B) chlorogenic acids in the coffee extract is preferably 5 × 10 ⁻² to 15 × 10 ⁻² (−), more preferably 6 × 10 ^{−2 to} 13 × 10 ⁻² (−), still more preferably 7 × 10
^{−2 to} 11 × 10 ⁻² (−), particularly preferably 8 × 10 ⁻² to 10 × 10 ⁻² (−).
v) The mass ratio [the amount of caffeine (% by mass) / the amount of solids (% by mass)] of the amount of solids in the coffee extract and the amount of caffeine is preferably 0.01-0. 07 (-), more preferably 0.02-0.06 (-), particularly preferably 0.03-0.05 (-).

  As described above, the coffee extract of the present invention is rich in chlorogenic acids, and the amount of hydroxyhydroquinone that inhibits the physiological action of chlorogenic acids is significantly reduced. As a result, the physiological action by chlorogenic acids can be sufficiently expected.

[Soluble coffee]
In the present invention, the coffee extract can be dried to obtain soluble coffee. Examples of the drying method include spray drying and freeze drying, but are not limited thereto. Examples of the shape of soluble coffee include powder, granules and tablets.

  The soluble coffee of the present invention preferably contains (B) chlorogenic acids in an amount of 5 to 25% by mass, more preferably 8 to 20% by mass, still more preferably 10 to 18% by mass, and particularly preferably 12 to 16% by mass.

[Coffee drink]
In the present invention, a coffee beverage may be produced using the obtained coffee extract. For coffee beverages, milk ingredients, sweeteners, bitterness inhibitors, antioxidants, fragrances, organic acids, organic acid salts, inorganic acids, inorganic acid salts, inorganic salts, pigments, emulsifiers, preservatives, seasonings, acidity Additives such as additives, vitamins, amino acids, pH adjusters, and quality stabilizers can be used alone or in combination.

  The coffee beverage of the present invention preferably contains (B) chlorogenic acids in an amount of 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass, and particularly preferably 0.1 to 0.3% by mass. .

The coffee beverage is provided as a container-packed beverage filled in an ordinary packaging container such as a molded container (so-called PET bottle) mainly composed of polyethylene terephthalate, a metal can, a paper container combined with a metal foil or a plastic film, or a bottle. be able to.
In addition, packaged beverages are manufactured under the sterilization conditions stipulated in the applicable regulations (Food Sanitation Law in Japan) if they can be sterilized by heating after filling in containers such as metal cans. it can. For PET bottles and paper containers that cannot be sterilized by retort, sterilize under the same conditions as above, for example, after sterilizing at high temperature and short time with a plate heat exchanger, etc. The method can be adopted.

(1) Analysis of chlorogenic acids (CGA) HPLC was used as an analytical instrument. The model numbers of the constituent units of the apparatus 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 × length 150 mm, particle diameter 3 μm (Intact Co.).

The analysis conditions are as follows.
Sample injection volume: 10 μL,
Flow rate: 1.0 mL / min,
UV-VIS detector setting wavelength: 325 nm,
Column oven set temperature: 35 ° C
Eluent A: 0.05 M acetic acid, 0.1 mM 1-hydroxyethane-1,1-diphosphonic acid, 10 mM sodium acetate, 5 (V / V)% acetonitrile solution,
Eluent B: acetonitrile.

Concentration gradient condition 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 a sample was precisely weighed, made up to 10 mL with eluent A, filtered through a membrane filter (GL chromatodisc 25A, pore size 0.45 μm, GL Sciences Inc.), and subjected to analysis.
Retention time of chlorogenic acids (unit: minutes)
(B ¹ ) Monocafe oil quinic acid: 5.3, 8.8, 11.6, total 3 points (B ² ) Monoferlaquinic acid: 13.0, 19.9, 21.0, total 3 points ( B ³ ) Dicaffeoylquinic acid: 36.6, 37.4, 44.2 in total.
From the area values of the nine types of chlorogenic acids determined here, (C) chlorogenic acid content (% by mass) was determined using 5-caffeoylquinic acid as a standard substance.

(2) Analysis of hydroxyhydroquinone (HHQ) by HPLC-electrochemical detector The analytical instrument used was a Couloarray system (model 5600A, manufactured by ESA, USA) which is an HPLC-electrochemical detector (coulometric type). The names and model numbers of the constituent units of the apparatus are as follows.
Analytical cell: Model 5010, Couloarray Organizer,
Couloarray electronics module software: Model 5600A,
Solvent delivery module: Model 582, gradient mixer,
Autosampler: Model 542, pulse damper,
Degasser: Degasys Ultimate DU3003,
Column oven: 505
Column: CAPCELL PAK C18 AQ inner diameter 4.6 mm × length 250 mm Particle diameter 5 μm (Shiseido Co., Ltd.).

The analysis conditions are as follows.
Sample injection volume: 10 μL,
Flow rate: 1.0 mL / min,
Applied voltage of electrochemical detector: 0 mV,
Column oven set temperature: 40 ° C
Eluent C: 0.1 (W / V)% phosphoric acid, 0.1 mM 1-hydroxyethane-1,1-diphosphonic acid, 5 (V / V)% methanol solution,
Eluent D: 0.1 (W / V)% phosphoric acid, 0.1 mM 1-hydroxyethane-1,1-diphosphonic acid, 50 (V / V)% methanol solution.

  For preparing the eluents C and D, distilled water for high performance liquid chromatography (Kanto Chemical Co., Ltd.), methanol for high performance liquid chromatography (Kanto Chemical Co., Ltd.), phosphoric acid (special grade, Wako Pure Chemical Industries, Ltd.) )), 1-hydroxyethane-1,1-diphosphonic acid (60% aqueous solution, Tokyo Chemical Industry Co., Ltd.).

Concentration gradient condition Time Eluent C Eluent D
0.0 minutes 100% 0%
10.0 minutes 100% 0%
10.1 min 0% 100%
20.0 minutes 0% 100%
20.1 minutes 100% 0%
50.0 minutes 100% 0%

  After accurately weighing 5 g of the sample, it was made up to 10 mL with 0.5 (W / V)% phosphoric acid, 0.5 mM 1-hydroxyethane-1,1-diphosphonic acid, 5 (V / V)% methanol solution. The solution was centrifuged and the supernatant was used as an analysis sample. This supernatant was passed through Bond Elut SCX (solid phase filling amount: 500 mg, reservoir volume: 3 mL, GL Sciences Inc.), and about 0.5 mL of the first passage solution was removed to obtain a passage solution. The passing liquid was filtered through a membrane filter (GL chromatodisc 25A, pore size 0.45 μm, GL Sciences Inc.) and immediately subjected to analysis.

  In the analysis under the above conditions of the HPLC-electrochemical detector, the retention time of (A) hydroxyhydroquinone was 6.38 minutes. From the peak area value obtained, hydroxyhydroquinone (Wako Pure Chemical Industries, Ltd.) was used as a standard substance, and (A) hydroxyhydroquinone content (mass%) was determined.

(3) Measurement of L value The sample was measured using the color difference meter (Spectrophotometer SE2000 by Nippon Denshoku Co., Ltd.).

(4) Measurement of Brix The sample was measured at 20 ° C. using a saccharimeter (Atago RX-5000α-Bev).

Example 1
Raw green coffee beans (Brazilian Arabica seeds) that have not been crushed are put into a vacuum constant temperature dryer (DP33, Yamato Scientific Co., Ltd., the same shall apply hereinafter) and heat-treated at 170 ° C. for 40 minutes under a reduced pressure of 1.3 kPa. Thus, roasted coffee beans of L23 were obtained. Next, the obtained roasted coffee beans were pulverized and sieved to obtain a particle size range between JIS standard sieve 42 mesh and 80 mesh. Ten parts by mass of 98 ° C. warm water was added to 1 part by mass of the roasted coffee beans, and stirring was performed (100 rpm) for 10 minutes while maintaining the liquid temperature at 95 ° C. or higher in a liquid nitrogen atmosphere. Subsequently, it poured into the commercially available coffee paper filter, and obtained the coffee extract. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

Example 2
L24 roasted coffee beans were obtained in the same manner as in Example 1 except that the treatment conditions were changed to 170 ° C. and 10 minutes. Next, a coffee extract was obtained from the roasted coffee beans obtained in the same manner as in Example 2. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

Example 3
L32 roasted coffee beans were obtained in the same manner as in Example 1 except that the treatment conditions were changed to 140 ° C. and 40 minutes. Next, a coffee extract was obtained from the roasted coffee beans obtained in the same manner as in Example 2. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

Example 4
Crushed green coffee beans (Brazilian Arabica seeds) were sieved to obtain a particle size range between JIS standard sieve 42 mesh and 80 mesh. Next, the collected green coffee beans were put into a vacuum constant temperature dryer, and subjected to heat treatment (first step) at 145 ° C. for 10 minutes under a reduced pressure of 1.3 kPa. Next, after the obtained coffee beans were cooled to 25 ° C. and returned to atmospheric pressure, they were put into a vacuum constant temperature drier and heat-treated at 145 ° C. for 10 minutes under a reduced pressure of 0.4 kPa (second step) ) To obtain roasted coffee beans of L27.
Next, the obtained roasted coffee beans were pulverized and sieved to obtain a particle size range between JIS standard sieve 42 mesh and 80 mesh. Next, a coffee extract was obtained by the same operation as in Example 1. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

Example 5
L27 roasted coffee beans were obtained in the same manner as in Example 4 except that the processing conditions of the first and second steps were changed to 140 ° C. and 10 minutes. Next, using the obtained roasted coffee beans, a coffee extract was obtained in the same manner as in Example 4. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

Comparative Example 1
Raw coffee beans (Brazilian Arabica) were roasted at 200 ° C. for 15 minutes under atmospheric pressure to obtain roasted coffee beans of L22. Next, the obtained roasted coffee beans were pulverized and sieved in the same manner as in Example 1, and a coffee extract was obtained in the same manner as in Example 1. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

Comparative Example 2
Raw coffee beans (Brazilian Arabica) were roasted at 170 ° C. for 60 minutes under atmospheric pressure to obtain roasted coffee beans of L22. Next, the obtained roasted coffee beans were pulverized and sieved in the same manner as in Example 1, and a coffee extract was obtained in the same manner as in Example 1. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

Comparative Example 3
A roasted coffee bean less than L19 was obtained in the same manner as in Example 1 except that the raw coffee bean (Brazilian Arabica seed) was changed to a treatment condition of 160 ° C. and 300 minutes under a reduced pressure of 1.3 kPa. It was. Subsequently, it grind | pulverized by the operation similar to Example 1, it sieved, and the coffee extract was obtained by the operation similar to Example 1. FIG. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

Comparative Example 4
Roasted coffee beans less than L19 were obtained in the same manner as in Comparative Example 2 except that the treatment conditions were changed to 140 ° C. and 300 minutes under reduced pressure of 1.3 kPa. Next, a coffee extract was obtained from the roasted coffee beans obtained in the same manner as in Comparative Example 2. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

Comparative Example 5
L19 roasted coffee beans were obtained in the same manner as in Comparative Example 2 except that the treatment conditions were changed to 120 ° C. and 600 minutes under reduced pressure of 1.3 kPa. Next, a coffee extract was obtained from the roasted coffee beans obtained in the same manner as in Comparative Example 2. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

Comparative Example 6
Crushed green coffee beans (Brazilian Arabica seeds) were sieved to obtain a particle size range between JIS standard sieve 42 mesh and 80 mesh. The roasted coffee beans of L19 were obtained in the same manner as in Comparative Example 2 except that raw coffee beans collected as raw materials were used and the processing conditions were changed to 120 ° C. and 300 minutes under reduced pressure of 1.3 kPa. It was. Next, a coffee extract was obtained from the roasted coffee beans obtained in the same manner as in Comparative Example 2. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

Comparative Example 7
Crushed green coffee beans (Brazilian Arabica seeds) were sieved to obtain a particle size range between JIS standard sieve 42 mesh and 80 mesh. L19 roasted coffee beans were obtained in the same manner as in Comparative Example 2 except that raw coffee beans collected as raw materials were used and the processing conditions were changed to 100 ° C. and 600 minutes under reduced pressure of 1.3 kPa. It was. Next, a coffee extract was obtained from the roasted coffee beans obtained in the same manner as in Comparative Example 2. Table 1 shows the analysis results of the roasted coffee beans and coffee extract obtained.

  From Table 1, it was confirmed that roasted coffee beans having a higher amount of chlorogenic acid and (A) a reduced amount of hydroxyhydroquinone were obtained by heat-treating green coffee beans under vacuum conditions. Moreover, it turned out that the amount of (A) hydroxyhydroquinone can be reduced notably by using a green coffee bean for heat processing several times.

Claims (7)

  A method for producing roasted coffee beans, comprising subjecting green coffee beans to heat treatment under vacuum at a temperature of less than 200 ° C for 5 to 250 minutes.   The method for producing roasted coffee beans according to claim 1, wherein the degree of vacuum is 7 kPa or less. The roasted coffee beans are roasted coffee beans having an L value of 20 to 40, and the mass ratio of (A) hydroxyhydroquinone and (B) chlorogenic acids in the roasted coffee beans [(A) / (B) ] Is 55 × 10 ⁻⁴ or less, and the chlorogenic acid content in the roasted coffee beans is 2.8 to 8% by mass. A first step of heating the green coffee beans under vacuum;
The manufacturing method of roasted coffee beans including the 2nd process of heat-processing the coffee beans obtained by the 1st process under vacuum.   The manufacturing method of the roasted coffee beans of Claim 4 which heat-processes at the temperature of 80-180 degreeC at 7 kPa or less for 3 to 60 minutes in a 1st process.   The manufacturing method of the roasted coffee beans of Claim 4 or 5 which heat-process at the temperature of 100-180 degreeC at 5 kPa or less for 3 to 60 minutes in a 2nd process. The roasted coffee beans are roasted coffee beans having an L value of 20 to 40, and the mass ratio of (A) hydroxyhydroquinone and (B) chlorogenic acids in the roasted coffee beans [(A) / (B) ] Is 55 × 10 ⁻⁴ or less, and the content of chlorogenic acids in the roasted coffee beans is 2.8 to 8% by mass. Manufacturing method.