JP2011055716A - Method for producing purified roasted coffee bean - Google Patents

Abstract

[PROBLEMS] To provide a method for producing a purified roasted coffee bean that has a high di-isomer content ratio of chlorogenic acids and a low hydroxyhydroquinone content ratio relative to the chlorogenic acids, and is capable of obtaining a coffee extract having a good flavor. To provide.
A method for producing refined roasted coffee beans, comprising heating raw roasted coffee beans at 80 to 150 ° C under atmospheric pressure at a temperature of 90 to 150 ° C under a vacuum condition of 6.7 kPa or less.
[Selection figure] None

Description

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

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

  However, it has been found that when coffee beans are roasted, hydroxyhydroquinone naturally occurs, 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 content and a low hydroxyhydroquinone content.

  Therefore, in order to reduce the hydroxyhydroquinone content of the roasted coffee beans, for example, the raw roasted coffee beans are subjected to aging treatment under a reduced-pressure atmosphere substituted with nitrogen under a temperature condition of 40 to 150 ° C. A method for producing brewed coffee beans 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

  The conventional production method is effective for reducing the hydroxyhydroquinone content of roasted coffee beans. However, the coffee extract obtained from such refined roasted coffee beans still has room for improvement because the flavor may be insufficient in some cases.

  Accordingly, an object of the present invention is to provide a purified roasted coffee that has a high di-form content ratio of chlorogenic acids and a low hydroxyhydroquinone content ratio with respect to the chlorogenic acids, and can obtain a coffee extract having a good flavor. It is to provide a method for producing beans.

  As a result of various studies to solve the above problems, the present inventors have conducted heat treatment of roasted coffee beans for a long time, or heat treatment at high temperature even for a short time, and only hydroxyhydroquinone from roasted coffee beans. In addition, the knowledge that the flavor component is also removed was obtained. The inventors of the present invention have further studied in detail, and as a result, the roasted coffee beans that have been heated to a predetermined temperature in advance are heat-treated at a predetermined temperature under an atmosphere controlled to a predetermined reduced pressure condition. It has been found that a purified roasted coffee bean can be obtained that not only has a high di-form content ratio and a low hydroxyhydroquinone content ratio relative to the chlorogenic acids, but can obtain a coffee extract with a good flavor.

  That is, the present invention provides a method for producing a purified roasted coffee bean, in which roasted coffee beans at 80 to 150 ° C. under atmospheric pressure are heat-treated at a temperature of 90 to 150 ° C. under a vacuum condition of 6.7 kPa or less. It is to provide.

According to the present invention, there is provided a method for producing a purified roasted coffee bean having a high di-isomer content ratio of chlorogenic acids and a low content ratio of hydroxyhydroquinone to the chlorogenic acids. In this way, a purified roasted coffee bean with a low content ratio of hydroxyhydroquinone that inhibits the physiological action of chlorogenic acids and a high di-isomer content ratio of chlorogenic acids effective for the expression of physiological action is obtained. Can be fully expected.
Moreover, since the coffee extract obtained from refined roasted coffee beans has good flavor, it is suitable for continuous intake over a long period of time.

First, terms used in this specification will be described.
“Chlorogenic acids” are monocaffeoylquinic acid of 3-caffeoylquinic acid, 4-caffeoylquinic acid and 5-caffeoylquinic acid, and 3-ferlaquinic acid, 4-ferlaquinic acid and 3-ferlaquinic acid. It is a collective term for ferlaquinic acid and 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid. The chlorogenic acid content is defined based on the total amount of the above nine types.
Further, the “di-form of chlorogenic acids (hereinafter simply referred to as“ di-form ”)” means dicaffeoylquinic acid, that is, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, and 4 , 5-dicaffeoylquinic acid, and the di-form content is defined on the basis of the total amount of the above three types. On the other hand, “mono-form of chlorogenic acids” (hereinafter simply referred to as “mono-form”) means 3-caffeoylquinic acid, 4-caffeoylquinic acid and 5-caffeoylquinic acid monocaffeoylquinic acid, It is a collective term for 3-ferlaquinic acid, 4-ferlaquinic acid, and 3-ferlaquinic acid, together with ferlaquinic acid, and the mono-body content is defined based on the total amount of the above six types.

Next, the manufacturing method of the roasted coffee beans of this invention is demonstrated.
(Preparation process)
First, raw roasted coffee beans are prepared.
Although the kind of coffee bean used by this invention is not specifically limited, For example, Brazil, Colombia, Tanzania, Mocha, Kilimangelo, Mandelin, and Blue Mountain are illustrated. In addition, coffee beans include Arabica and Robusta. One kind of coffee beans may be used, or a plurality of kinds may be blended and used.

Examples of the roasting degree of coffee beans include light, cinnamon, medium, high, city, full city, french and italian. Among these, light, cinnamon, medium, high, and city are preferable because they contain a large amount of chlorogenic acids and are easy to drink.
The L value of the raw roasted coffee beans is preferably 16 to 24, more preferably 18 to 24, and particularly preferably 19 to 23. When the L value is within the above range, the effect of reducing hydroxyhydroquinone and the effect of improving the flavor can be sufficiently expressed. Here, the “L value” in this specification is a value obtained by measuring the brightness of raw roasted coffee beans with a color difference meter, with black as L value 0 and white as L value 100. In other words, the L value is an index representing the degree of roasting of coffee beans. The deeper the roasted coffee beans, the darker the coffee beans are, and the lower the L value, the lower the roasting degree. L value becomes a high value.

As a roasting method of coffee beans, a known method can be appropriately selected. For example, the roasting temperature is preferably 180 to 300 ° C., more preferably 180 to 250 ° C., particularly preferably 200 to 250 ° C., and the roasting degree of the coffee beans is within the above range under such temperature conditions. It can be heated until.
Moreover, as a heating method of the roasting method, for example, a direct fire type, a hot air type, a semi-hot air type, etc. are exemplified, and it is particularly preferable to combine a type using a rotating drum with any of these.
After roasting, it is preferable to cool to 0-100 degreeC within 30 minutes from a viewpoint of flavor, Most preferably, it is 10-60 degreeC.

(Preheating process)
Next, the temperature of the raw roasted coffee beans is set to a predetermined temperature of 80 to 150 ° C. under atmospheric pressure. This makes it easier to remove hydroxyhydroquinone while leaving the flavor component. As a result, it is possible to reduce the content ratio of hydroxyhydroquinone to chlorogenic acids without impairing the flavor.
As a temperature setting method, for example, the following method (i) or (ii) is exemplified, but if the temperature of the raw roasted coffee beans is within the predetermined range during the heat treatment step described later, It is not particularly limited.
(I) A method of heating raw roasted coffee beans that have been cooled to room temperature after roasting so that the predetermined temperature is reached.
(Ii) A method of maintaining the predetermined temperature while slowly cooling the roasted coffee beans after roasting.

Further, in the method (i), the following method is exemplified.
1) A method of heating the apparatus so that the raw roasted coffee beans are at the predetermined temperature after the raw roasted coffee beans are put into the apparatus.
2) A method in which raw roasted coffee beans are charged into an apparatus that has been heated to the predetermined temperature in advance and heated until the raw roasted coffee beans reach the predetermined temperature.
3) A method in which roasted coffee beans previously heated to the predetermined temperature are charged into the apparatus, and the apparatus is heated so that the raw roasted coffee beans maintain the predetermined temperature.
4) A method in which after heating the apparatus and roasted coffee beans to the predetermined temperature in advance, the heated raw material roasted coffee beans are put into the heated apparatus.

Although the heating temperature of roasted coffee beans is 80 to 150 ° C., it is preferably a temperature lower than the heat treatment step described later. Specifically, the preheating temperature is preferably 80 to 95 ° C, particularly 80 to 90 ° C from the viewpoint of flavor. The preheating time is preferably 10 to 20 minutes.
The roasted coffee beans may be unground or crushed, but are preferably pulverized. Although the magnitude | size of a ground coffee bean can be selected suitably, it is 30-100 mesh, for example.

  The apparatus to be used is not particularly limited as long as the pressure can be adjusted freely and can be heated to the predetermined temperature. Examples of the apparatus include a roasted bean stationary type, a roasted bean transfer type, and a roasted bean stirring type. Is done. Specifically, a shelf dryer, a conveyor dryer, a rotary drum dryer, a rotary V dryer, or the like can be used. Furthermore, you may use the roaster which can adjust pressure. Examples of the heating source include hot air, far infrared rays, infrared rays, microwaves, and superheated steam.

(Heat treatment process)
Next, the raw material roasted coffee beans heated to a predetermined temperature in advance are heated at a temperature of 90 to 150 ° C. under a vacuum condition of 6.7 kPa or less. Thereby, hydroxyhydroquinone can be efficiently removed while the flavor component in roasted coffee beans remains. As a result, it is possible to obtain purified roasted coffee beans having a low content of hydroxyhydroquinone to chlorogenic acids and having a good flavor.
The heating temperature is 90 to 150 ° C., but preferably 95 to 145 ° C., particularly preferably 100 to 130 ° C., from the viewpoint of reducing the hydroxyhydroquinone content and flavor.
The degree of vacuum is 6.7 kPa or less, but is preferably 4 kPa or less, more preferably 2.7 kPa or less, and particularly preferably 1.0 kPa or less, from the viewpoint of reduction of hydroxyhydroquinone content and flavor. 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 treatment time is preferably 1 to 10 hours, particularly preferably 3 to 7 hours, from the viewpoint of reducing the hydroxyhydroquinone content and flavor.

  Thus, although the refined roasted coffee beans of the present invention can be obtained, the obtained refined roasted coffee beans can have the following characteristics (I) to (VI). The characteristics (II) to (IV) are obtained from the following formulas (1) to (3) from the chlorogenic acid content, hydroxyhydroquinone content and solid content of the coffee extract obtained from the refined roasted coffee beans. There are extraction conditions and analysis methods described in the examples below.

Chlorogenic acid content in refined roasted coffee beans [mg / 100 g] = Concentration of chlorogenic acids in coffee extract [mg / 100 g] × Coffee extract mass [g] / Purified roasted coffee bean mass [g])・ (1)
Hydroxyquinone content in refined roasted coffee beans [mg / kg] = Hydroxyquinone concentration in coffee extract [mg / kg] x Coffee extract mass [kg] / Mass of refined roasted coffee beans [kg] (2)
Water-soluble solid content in refined roasted coffee beans [%] = Solid content in coffee extract [%] × Mass of coffee extract [g] / Mass of refined roasted coffee beans [g] (3)

(I) The L value of refined roasted coffee beans is preferably 16 to 24, more preferably 18 to 22, and particularly preferably 19 to 21 from the viewpoint of flavor.
(II) The content of chlorogenic acids in the refined roasted coffee beans is preferably 1 to 4 g, more preferably 1.2 to 3 g, and particularly preferably 1.5 to 2 g per 100 g of the refined roasted coffee beans from the viewpoint of physiological effects.
(III) From the viewpoint of physiological effect, the content of hydroxyhydroquinone in the refined roasted coffee beans is 180 mg or less per kg of refined roasted coffee beans, further 170 mg or less, more 160 mg or less, more 150 mg or less, particularly 140 mg or less. Is preferred. The lower limit is preferably 10 mg from the viewpoint of production efficiency.
(IV) The amount of water-soluble solid content in the refined roasted coffee beans is preferably 20 to 35%, particularly preferably 22 to 30% from the viewpoint of flavor.
(V) The mass ratio of hydroxyhydroquinone / chlorogenic acids in the refined roasted coffee beans is 1 × 10 ^{−4 to} 100 × 10 ⁻⁴ , and further 1 × 10 ^{−4 to} 90 × 10 ⁻⁴ from the viewpoint of physiological effects. In particular, it is preferably 10 × 10 ⁻⁴ to 80 × 10 ⁻⁴ .
(IV) The mass ratio of the di-form / mono-form in the refined roasted coffee beans is preferably 4 × 10 ⁻² or more, more preferably 4.5 × 10 ⁻² or more, from the viewpoint of flavor. The upper limit is preferably 8 × 10 ⁻² from the viewpoint of production efficiency.

(Coffee extract)
In the present invention, a coffee extract may be obtained using the purified roasted coffee beans. The “coffee extract” referred to here is one in which purified 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 the purified roasted coffee beans as they are, or may be extracted after drying the purified roasted coffee beans.
The pulverization degree of the refined roasted coffee beans used for extraction can be appropriately selected. For example, ultrafine grinding (0.250-0.500 mm), fine grinding (0.300-0.650 mm), medium Fine grinding (0.530-1.000 mm), Medium grinding (0.650-1.500 mm), Medium coarse grinding, Coarse grinding (0.850-2.100 mm), Very coarse grinding (1.000-2. 500 mm) and cut products having an average particle size of 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. The extraction time of batch type extraction or semi-batch type extraction, that is, the contact time or residence time with refined roasted coffee beans is preferably 10 seconds to 120 minutes, particularly preferably 30 seconds to 30 minutes, from the viewpoint of flavor. .
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. Although the pH (25 degreeC) of an extraction solvent is 4-10 normally, 5-7 are preferable from a 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 the refined roasted coffee beans.

From the viewpoint of flavor stability, the solid content in the coffee extract is preferably 0.1% or more, more preferably 0.5 to 30%, still more 1 to 20%, and particularly preferably 2 to 10%. The “solid content” can be quantified by the method described in “Measurement of Brix” in Examples described later.
The content of chlorogenic acids in the coffee extract is preferably 1 to 10%, more preferably 3 to 8%, particularly 5 to 7% per solid content of the coffee extract from the viewpoint of physiological effects. The “chlorogenic acid content in the coffee extract” can be quantified by the method described in “Analyzing Method of Chlorogenic Acids” in the Examples below.
The hydroxyhydroquinone content in the coffee extract is preferably 0.8% or less, more preferably 0.7% or less, particularly preferably 0.6% or less, based on the solid content of the coffee extract, from the viewpoint of physiological effects. In addition, a minimum is 0.001% per solid content of the said coffee extract from production efficiency and an economical viewpoint. The “hydroxyhydroquinone content” can be quantified by the method described in “Method for Analyzing Hydroxyhydroquinone” in Examples below.
The mass ratio of hydroxyhydroquinone to chlorogenic acids in the coffee extract (hydroxyhydroquinone / chlorogenic acids) is 100 × 10 ⁻⁴ or less, more preferably 90 × 10 ⁻⁴ or less, particularly 80 × 10 ⁻⁴ from the viewpoint of physiological effects. The following is preferable. The lower limit is 1 × 10 ⁻⁴ from the viewpoint of production efficiency and economy.
The mass ratio of di-form / mono-form in the coffee extract is preferably 4 × 10 ⁻² or more, more preferably 4.5 × 10 ⁻² or more, and particularly preferably 5 × 10 ⁻² or more. The upper limit is preferably 8 × 10 ⁻² from the viewpoint of production efficiency.
In this way, a coffee extract with a high di-isomer content ratio of chlorogenic acids that is effective in expressing physiological effects as well as a low content ratio of hydroxyhydroquinone that inhibits physiological actions of chlorogenic acids can be obtained. The effect can be fully 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.

(Coffee composition)
In the present invention, a coffee composition may be produced using the obtained coffee extract. Coffee compositions are milk components, sweeteners, bitterness inhibitors, antioxidants, fragrances, organic acids, organic acid salts, inorganic acids, inorganic acid salts, inorganic salts, pigments, emulsifiers, preservatives, seasonings, acidity You may mix | blend additives, such as a foodstuff, a vitamin, an amino acid, a pH adjuster, and a quality stabilizer, individually or in combination.

The coffee composition is provided as a container-packed beverage filled in ordinary packaging containers such as molded containers (so-called PET bottles), metal cans, paper containers combined with metal foil or plastic film, bottles, etc. mainly composed of polyethylene terephthalate can do.
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) Methods for analyzing chlorogenic acids (CGA), mono- and di-forms The analytical instrument used was HPLC. 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)
(A1) Monocafe oil quinic acid: 5.3, 8.8, 11.6 total 3 points (A2) Ferlaquinic acid: 13.0, 19.9, 21.0 total 3 points (A3) Dicafe Oil quinic acid: 36.6, 37.4, 44.2 in total.
From the area values of the nine types of chlorogenic acids determined here, the content of chlorogenic acids (mg / 100 g) was determined using 5-caffeoylquinic acid as a standard substance.

(2) Analysis method 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 hydroxyhydroquinone was 6.38 minutes. From the peak area value obtained, hydroxyhydroquinone (Wako Pure Chemical Industries, Ltd.) was used as a standard substance, and the hydroxyhydroquinone content (mg / kg) 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 using a saccharimeter (Atago RX-5000α-Bev, Inc.).

(5) Sensory test About the richness, the savory taste, and flavor of the coffee extract obtained by each Example and the comparative example, five panelists evaluated by the following reference | standard, and decided the score by consultation after that.

(Body evaluation criteria)
5: Very felt 4: Feeled 3: Slightly felt 2: Not felt very much 1: Not felt almost

(Egu taste evaluation criteria)
5: I can hardly feel it 4: I don't feel it very much 3: It feels a little 2: It feels 1: It feels very much

(Flavor evaluation criteria)
5: Very felt 4: Feeled 3: Slightly felt 2: Not felt very much 1: Not felt almost

Production Example 1
Colombian coffee beans were roasted at 200 ° C. to obtain L22 raw material roasted coffee beans. Table 1 shows analytical values of roasted coffee beans.

Production Example 2
(Manufacture of raw roasted coffee beans)
Colombian coffee beans were roasted at 200 ° C. to obtain raw roasted coffee beans of L19. Table 1 shows analytical values of roasted coffee beans.

Example 1
After the raw roasted coffee beans of L22 that have not been crushed are preheated to 80 ° C. at atmospheric pressure, they are put into a vacuum constant temperature dryer (DP33, Yamato Scientific Co., Ltd.), under a reduced pressure of 1.3 kPa, Heat treatment was performed at 140 ° C. for 5 hours to obtain L19 refined roasted coffee beans. Table 2 shows the analysis results of the obtained purified roasted coffee beans.
Subsequently, the obtained refined roasted coffee beans were pulverized to obtain a particle size range between JIS standard sieve 42 mesh and 80 mesh. Next, an extract was obtained using 10 parts of 98 ° C. warm water with respect to 1 part of the pulverized beans. In addition, extraction conditions are 95 degreeC or more holding | maintenance, a liquid surface nitrogen atmosphere, stirrer stirring (100 rpm), and 10 minutes. Subsequently, it poured into the commercially available coffee paper filter, and obtained the coffee extract. Table 2 shows the analysis results and sensory test results of the obtained coffee extract.

Example 2
A refined roasted coffee bean of L19 was produced in the same manner as in Example 1 except that the degree of vacuum was changed to 0.4 kPa and the heating temperature under reduced pressure was changed to 120 ° C. Table 2 shows the analysis results of the obtained purified roasted coffee beans.
Next, using the obtained purified roasted coffee beans, a coffee extract was obtained in the same manner as in Example 1. Table 2 shows the analysis results and sensory test results of the obtained coffee extract.

Example 3
L22 roasted coffee beans were pulverized to obtain a particle size range between JIS standard sieve 42 mesh and 80 mesh. Next, this crushed bean was used as a raw roasted coffee bean, the vacuum degree was changed to 0.4 kPa, and the heat treatment under reduced pressure was changed to 120 ° C., respectively, in the same operation as in Example 1. L19 refined roasted coffee beans were produced. Table 2 shows the analysis results of the obtained purified roasted coffee beans.

Comparative Example 1
A refined roasted coffee bean of L19 was produced in the same manner as in Example 1 except that the heating temperature under reduced pressure was changed to 160 ° C. Table 2 shows the analysis results of the obtained purified roasted coffee beans.
Next, using the obtained purified roasted coffee beans, a coffee extract was obtained in the same manner as in Example 1. Table 2 shows the analysis results and sensory test results of the obtained coffee extract.

Comparative Example 2
Using the roasted coffee beans of L19, a coffee extract was obtained in the same manner as in Example 1. Table 2 shows the analysis results of the raw roasted coffee beans of L19, the analysis results of the obtained coffee extract, and the results of the sensory test.

From Table 2, it was confirmed that purified roasted coffee beans having a low content ratio of hydroxyhydroquinone to chlorogenic acids can be obtained by performing heat treatment under reduced pressure at a temperature of 90 to 150 ° C.
Moreover, the coffee extract obtained from the refined roasted coffee beans of Examples 1 to 3 has a richer flavor and a bitter taste than the coffee extract obtained from the raw roasted coffee beans of Comparative Example 2. It had a good flavor and was easy to drink.

Example 4
L20 refined roasted coffee beans were produced in the same manner as in Example 1 except that the degree of vacuum was changed to 1.8 kPa and the heating temperature under reduced pressure was changed to 100 ° C. Table 3 shows the analysis results of the obtained purified roasted coffee beans.
Next, using the obtained purified roasted coffee beans, a coffee extract was obtained in the same manner as in Example 1. Table 3 shows the analysis results and sensory test results of the obtained coffee extract.

Comparative Example 3
L20 refined roasted coffee beans were produced in the same manner as in Example 4 except that the degree of vacuum was changed to 1.8 kPa and the heating temperature under reduced pressure was changed to 80 ° C. Table 3 shows the analysis results of the obtained purified roasted coffee beans.
Next, using the obtained purified roasted coffee beans, a coffee extract was obtained in the same manner as in Example 1. Table 3 shows the analysis results and sensory test results of the obtained coffee extract.

Comparative Example 4
A refined roasted coffee bean of L20 was produced in the same manner as in Example 4 except that the degree of vacuum was changed to 13.3 kPa. Table 3 shows the analysis results of the obtained purified roasted coffee beans.
Next, using the obtained purified roasted coffee beans, a coffee extract was obtained in the same manner as in Example 1. Table 3 shows the analysis results and sensory test results of the obtained coffee extract.

Comparative Example 5
A refined roasted coffee bean of L20 was produced in the same manner as in Example 4 except that the heat treatment was performed at a normal pressure of 101.3 kPa. Table 3 shows the analysis results of the obtained purified roasted coffee beans.
Next, using the obtained purified roasted coffee beans, a coffee extract was obtained in the same manner as in Example 1. Table 3 shows the analysis results and sensory test results of the obtained coffee extract.

Comparative Example 6
In the same manner as in Example 4, except that the preheating temperature of the raw roasted coffee beans was 25 ° C., the vacuum degree was changed to 0.4 kPa, and the heating temperature under reduced pressure was changed to 120 ° C. Refined roasted coffee beans were produced. Table 3 shows the analysis results of the obtained purified roasted coffee beans.
Next, using the obtained purified roasted coffee beans, a coffee extract was obtained in the same manner as in Example 1. Table 3 shows the analysis results and sensory test results of the obtained coffee extract.

Comparative Example 7
The operation of L19 was performed in the same manner as in Example 4 except that the preheating temperature of the raw roasted coffee beans was changed to 60 ° C., the degree of vacuum was changed to 0.4 kPa, and the heating temperature under reduced pressure was changed to 120 ° C. Refined roasted coffee beans were produced. Table 3 shows the analysis results of the obtained purified roasted coffee beans.
Next, using the obtained purified roasted coffee beans, a coffee extract was obtained in the same manner as in Example 1. Table 3 shows the analysis results and sensory test results of the obtained coffee extract.

From Table 3, if the heating temperature under reduced pressure is low even if the degree of vacuum is sufficient, or if the degree of vacuum is low even if the heating temperature is sufficient, the di-form in chlorogenic acids decomposes and the di-form content ratio It was also found that the content ratio of hydroxyhydroquinone to chlorogenic acids was increased, and the flavor of the coffee extract was insufficient (Comparative Examples 3 to 5).
In addition, if the temperature of the preheating of the raw roasted coffee beans is too low, even if the subsequent heat treatment conditions are sufficient, both the di-form content ratio of chlorogenic acids and the content ratio of hydroxyhydroquinone to chlorogenic acids are insufficient, And it turned out that the flavor of a coffee extract also becomes inadequate (Comparative Examples 6-7).
From these results, it is clear that the preheating temperature of the raw roasted coffee beans is 80 to 150 ° C., and that the heat treatment is performed at a temperature of 90 to 150 ° C. under a vacuum condition of 6.7 kPa or less. became.

Claims (7)

  A method for producing purified roasted coffee beans, wherein raw roasted coffee beans at 80 to 150 ° C under atmospheric pressure are heat-treated at a temperature of 90 to 150 ° C under vacuum conditions of 6.7 kPa or less.   The manufacturing method of Claim 1 whose L value of raw material roasted coffee beans is 16-24.   The manufacturing method of Claim 1 or 2 whose heat processing time of raw material roasted coffee beans is 3 to 7 hours.   The production method according to any one of claims 1 to 3, wherein the raw roasted coffee beans are pulverized. L value is 16-24,
The content of hydroxyhydroquinone is 180 mg or less per kg of the refined roasted coffee beans,
The content of chlorogenic acids is 1 to ⁴ g per 100 g of the refined roasted coffee beans, and the content mass ratio of hydroxyhydroquinone to chlorogenic acids is 1 × 10 ^{−4 to} 100 × 10 ⁻⁴ .
Refined roasted coffee beans. A coffee extract obtained from roasted coffee beans having an L value of 16 to 24 of purified roasted coffee beans, wherein the hydroxyhydroquinone content is 0.8% or less per solid content of the coffee extract, A coffee extract in which the content of chlorogenic acids is 1 to 10% per solid content of the coffee extract and the mass ratio of hydroxyhydroquinone to chlorogenic acids is 1 × 10 ^{−4 to} 100 × 10 ⁻⁴ .   Soluble coffee obtained by spray drying or freeze drying the coffee extract according to claim 6.