JP2013042709A - Method for producing coffee extract liquid by batch system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a coffee extract liquid which enables its coffee flavor component to be extracted while separated from its bitterness component.SOLUTION: The method for producing a coffee extract liquid by passing a solvent through a layer of ground coffee beans and retrieving the resultant extract liquid includes a step of retaining the solvent in the layer of ground coffee beans left at rest in a nearly sealed condition; wherein, the amount of the solvent is 0.3-2 times the volume of ground coffee beans and the retention time of the solvent in the layer of ground coffee beans is 5-60 min.

Description

  The present invention relates to a method for producing a coffee extract in which excessive scorching bitterness associated with roasting coffee beans is reduced.

  A coffee extract obtained by pulverizing roasted coffee beans into granules (hereinafter referred to as coffee granules) extracted with hot water or water is used for drinking as a coffee beverage. Coffee beverages are known to contain over 300 types of flavor components and about 10 types of nutritional components, and play a role not only as beverages but also as nutritional functional beverages. Therefore, it is important to obtain a savory coffee extract in order to continue ingesting a coffee beverage in a normal life for a long period of time.

  Extract coffee is known as a savory coffee extract. Extract coffee is the first few drops of coffee when it is extracted, and it is a thick and fragrant coffee liquid that is succulent when put in the mouth, has a good aftertaste, and disappears cleanly. There is a report that coffee that draws out the charm to the maximum is the supreme coffee (Non-Patent Document 1).

  A method for improving the flavor of the coffee extract by selectively removing unpleasant components has also been reported. For example, using activated carbon with an average repore radius of around 30 to 100 mm as an adsorbent, selectively adsorbs high-molecular brown components such as chlorogenic acid multimers that cause astringency in coffee extracts. There is a method (Patent Document 1) that reduces the bitterness and astringency of tannin, caffeine, etc. by combining a method of removing (Patent Document 1) and an enzyme treatment and an adsorption treatment with activated carbon, PVPP, activated clay, or the like.

  On the other hand, it is known that coffee extraction is performed by batch processing. Specifically, in a state where a filter or the like is mounted inside a cylindrical tank that is erected and held, raw materials such as coffee beans that have been crushed after roasting are put into the tank and heated using steam or the like. Hot water is poured from above the filter and the like, and a predetermined amount of raw material is filtered to obtain an extract (Patent Documents 3 and 4). And according to this batch process, it is known that the soluble solid content of the obtained extract is about 2% at the maximum. Moreover, the immersion method which restrict | limits the amount of hot water and leaves it for a fixed time is also disclosed (nonpatent literature 3).

Japanese Patent No. 2578316 JP 2003-310162 A Japanese Utility Model Publication No. 64-3584 JP-A 64-5452

Yukio Hirose, et al., Coffee Studies, Human Sciences (Tokyo), 2003 M.R.Jisha, et al., Mater. Chem. Phys., 115, 33-39, 2009 Makoto Takagi, Coffee Culture Research, 15, 113-134, 2008

  Traditionally, bitterness and astringency, which are unpleasant ingredients, have been reduced, but even if bitterness is sufficient, astringency is not sufficient, or bitterness and astringency can be removed, but at the same time it is unique to coffee The rich aroma, flavor, and richness of the coffee can be removed, and the flavor of the coffee extract itself may be reduced.

  An object of this invention is to provide the manufacturing method of the coffee extract which can reduce excessive bitterness selectively, with the preferable flavor component of coffee intact. It is another object of the present invention to provide a method for producing a coffee extract having a good flavor in which excessive bitterness and astringency are selectively reduced without changing the preferred coffee flavor components.

  As known for extract coffee, the roasted bean surface has more aroma components than the inside, so that a flavor-rich extract can be efficiently obtained with a small amount of extract. However, the strong bitter component produced in the final stage of roasting is adsorbed on the outermost surface of the coffee beans, and excessive bitterness is expressed in the extract on the roasted bean surface (referred to as “burnt bitterness” in this specification). It is difficult to obtain a coffee extract with a balanced sourness, bitterness, and richness.

As a method for solving the above-mentioned problems, the present inventors diligently studied a method for selectively removing the burning bitterness from the extract on the roasted bean surface. It is known that when coffee beans are roasted, a honeycomb structure (honeycomb structure) is formed, and the honeycomb structure partition walls have a surface area that is comparable to that of a porous gel and have a component adsorption capacity. It has been reported (Non-Patent Document 2). The present inventors have surprisingly found that the burnt bitter component has a strong affinity with the partition walls of the honeycomb structure of coffee beans. And, by allowing the extraction solvent to forcibly pass through the coffee granules under standing and holding for a certain period of time, the burnt bitter components in the extract can be selectively adsorbed to the exposed honeycomb structure partition walls and separated and extracted. As a result, the present invention has been completed. That is, the present invention relates to the following.
(1) A coffee extract containing a step of retaining a solvent in a coffee granule layer that is allowed to stand in a substantially sealed state in the production of a coffee extract by passing a solvent through the coffee granule layer and recovering the extract Manufacturing method.
(2) The method according to (1), wherein the solvent amount is 0.3 to 2 times the volume of the coffee granules.
(3) The method according to (1) or (2), wherein the retention time of the solvent in the coffee granule layer is 5 to 60 minutes.
(4) The method according to any one of (1) to (3), wherein a column type extractor is used.

  The production method of the present invention provides a method for producing a coffee extract that can selectively reduce excessive bitterness while maintaining the preferred coffee flavor components.

FIG. 1 is a diagram showing an example of a method for producing a coffee extract by a batch method. As a method for placing the coffee granules in a stationary state, an embodiment in which the coffee granules M are held by the coffee holding plates 5 and 6 (FIG. 1 (1)), and an embodiment in which the entire accumulated layer of the coffee granules M is covered by the coffee holding bags 7 ( FIG. 1 (2)) is shown. FIG. 2 is a diagram showing an embodiment using a closed extraction column. FIG. 3 is a diagram showing an example of a method for producing a coffee extract by the batch method of the present invention. FIG. 4 is a diagram showing an example of a method for producing a coffee extract by the batch method of the present invention.

  Coffee beans evaporate water by roasting process, hollow the internal cellular tissue to form a honeycomb structure, and the carbon dioxide gas, aroma component, taste component (water-soluble) of coffee on the uneven surface (partition) of the hollowed cell membrane Adsorbs taste components). In the production method of the present invention, the aroma component and taste component adsorbed on the surface of the honeycomb structure (water-soluble taste component, bitterness component) are once desorbed by passing a small amount of extraction solvent, and the honeycomb structure After the surface is exposed, the burnt bitter component of the desorbed components is selectively captured (re-adsorbed) to separate and remove the roasted coffee beans with the exposed honeycomb structure surface. It is the biggest feature to use as. In order to use the honeycomb structure of coffee beans as an adsorbent, it is important to forcibly pass a small amount of extraction solvent through the coffee granules in a stationary state and hold them for a certain period of time.

  As used herein, the “still state of coffee granules” refers to a state in which coffee granules are accommodated in the extraction section in a substantially sealed manner, and the coffee granules are danced in the extraction section when the extraction solvent is passed through. It means no state. Specifically, it means a state in which the accumulated layer of coffee granules is surrounded by the wall of the extraction unit, the filter medium, the lid material, and the like.

  In the present invention, the method for placing the coffee granules in a stationary state is not limited. Examples include a method of holding the coffee granules M with the coffee holding plates 5 and 6 (see FIG. 1 (1)) and a method of covering the entire accumulation layer of the coffee granules M with the coffee holding bag 7 (see FIG. 1 (2)). . The coffee holding plate and the coffee holding bag need to select the shape and material inscribed in the extraction section in order to accommodate the coffee granules in a substantially sealed manner, but the extraction solvent can be passed through, so that the coffee granules and the extraction liquid If it can isolate | separate, it will not specifically limit. Specifically, a mesh member such as a metal mesh, a non-woven fabric (such as flannel cloth or lint cloth), a paper filter, etc. can be exemplified, and a flat, conical, pyramidal shape or the like can be used. If the mesh of the mesh member is made too small, clogging is likely to occur, and extraction may take time and may cause over-extraction. Therefore, in the case of a metal mesh, the mesh size is about 20 to 200 American meshes. Are preferably used. Moreover, it is preferable to use a nonwoven fabric from a viewpoint which can adsorb and remove the oil contained in the coffee extract.

  When the coffee holding plate is used, the coffee holding plate is installed at a position in contact with or close to the uppermost surface of the accumulated layer of the dried coffee granules M so that the coffee granules are substantially sealed. The adjacent position refers to a position separated from the uppermost surface of the deposited layer of the coffee granules M by an amount that allows the coffee granules to naturally swell when the coffee granules M are wetted with the extraction solvent. Specifically, from the position where the coffee granules are slightly compressed (about 0.9 times the volume of the coffee granules), considering the swelling of the coffee granules after contact with the extraction solvent, about twice the volume of the coffee granules The area between the position corresponding to (preferably about 1.5 times) is indicated.

  In the present invention, the extraction solvent is passed through and held in the coffee granules under standing. As the extraction solvent, water at 15 to 100 ° C., preferably hot water at 50 to 98 ° C. is preferably used. In particular, when hot water at 60 to 95 ° C. is used, it has been confirmed that a coffee extract having a strong aroma and a strong sweet taste can be obtained.

  The present invention is characterized in that a small amount of extraction solvent is passed through. If the amount of extracted solvent is large, the effect of roasted coffee beans as an adsorbent will not be fully exerted, and the separation efficiency of burnt bitterness will deteriorate, or if the amount of extracted solvent is large or the retention time is too long, The miscellaneous taste may be extracted from the inside of the bean and the flavor of the extract may be lowered. The amount of the extraction solvent is about 0.3 to 2 times the volume of the coffee granule M, preferably about 0.5 to 1.5 times, more preferably about the upper surface of the deposited layer of the coffee granule M. Is the amount to be. The injection amount of the extraction solvent may be controlled by providing a liquid level meter in the extraction column, or may be calculated from the volume of the coffee granule layer. In general, the bulk specific gravity of medium roasted and ground coffee granules is 0.3 to 0.5. From this bulk specific gravity and the inner diameter of the extraction column, those skilled in the art can determine the volume of extraction solvent necessary to fill the upper surface of the extraction section. The retention time of the extraction solvent is about 5 to 60 minutes, preferably about 7 to 45 minutes.

  After holding for a certain time, the extract is recovered. The means for collecting is not particularly limited, and automatic dropping by gravity, pumping by a pump, and the like are conceivable. For the purpose of preventing desorption of the burnt bitter component adsorbed on the partition wall surface of the honeycomb structure, SV (space velocity) = about 3 to 100, preferably SV = 5 to 70, more preferably 5 to 50, particularly preferably about 6 to 40. It is good to collect at.

  The present invention can be carried out using a column type extractor. The column-type extractor includes a coffee holding plate for containing the coffee granules inside in a substantially sealed manner, a supply port for the extraction solvent and the extract A, and a take-out port for the coffee extract A and the coffee extract B. If it is a thing, it will not specifically limit. For example, a type that supplies the extraction solvent from the upper side of the column type extractor, a type that supplies the extraction solvent from the lower side, or a type that can supply the extraction solvent from both sides can be used.

  As the column type extractor, for example, a closed type extraction column (hereinafter, also simply referred to as “column”) as shown in FIG. 2 can be used. A column 1 shown in FIG. 2 includes an extraction unit E for extracting coffee, a pump 2 for supplying an extraction solvent for extraction from an extraction solvent tank 3 (for example, a water or hot water tank), and an extract A. It is configured with a tank 4 for collection, and is equipped with coffee holding plates 5 and 6 having a shape that is detachable and inscribed in the brewing part E, which can accommodate the coffee granules M in a stationary state.

  Here, in this specification, the coffee granule M is stored in a substantially sealed state, that is, in the position of the coffee holding plate 5 installed in the lower part of the coffee granule M in FIG. An area between the position of the coffee holding plate 6 provided at a position close to the upper surface of the granule deposition layer is referred to as an extraction unit E.

  In order to prevent over-extraction due to local contact of the extraction solvent with the coffee granules, it is preferable to use a column having an extraction part having a shape in which the extraction solvent easily contacts the coffee granules uniformly. Specifically, it has a shape having a substantially uniform inner diameter, for example, a columnar shape, a rectangular parallelepiped shape, or the like with respect to the flow direction of the extraction solvent (in FIG. 2, the antigravity direction (the direction from the bottom to the top)). It is preferable to use a column. When such a column is used, the cross-sectional shape of the coffee granule accumulation layer in the direction along the shaft boat is substantially rectangular.

  In general, the ratio of the width (L) to the height (H) of the quadrangular width (L) and the height (H) in the cross-sectional shape of the quadrangular shape in the direction along the axis of the extraction part E, although depending on the characteristics such as the particle size of the coffee granules. / L) is preferably 0.1 to 10, preferably 2 to 6, and more preferably 3 to 6 so that the coffee granule M is accommodated in the extraction part E. If the above range is exceeded, extraction may take time or clogging may occur, resulting in overextraction. Moreover, if it is less than said range, the adsorption effect of this invention may not fully be acquired.

  In the following, further embodiments of the invention will be described. FIG. 3 shows the coffee brewing apparatus 1 in which the injection means is connected to the side wall of the granule container 52. The coffee granules M are accommodated in a substantially sealed shape in the granule accommodating portion 52 having the lid 53 using the braking members 10 and 11. Next, the extraction solvent is gently injected from the injection means connected to the side wall of the granule container 52. The injection means includes a first supply path 51 and a first supply valve 51A connected in the middle of the first supply path 51, and the first supply path 51 includes a first extraction solvent tank 54. Is communicated. The first supply path 51 is connected to the side wall opening 52 of the granule container 52. In this embodiment, since the extraction solvent gently flows along the surface of the side wall of the granule container 52, there is an advantage that the granule is placed still. That is, the disorder | damage | failure etc. of the coffee granule M by the momentum at the time of injection | pouring of an extraction solvent are suppressed, and stability can be maintained. The supply valve 51A is opened or closed to inject a predetermined amount of the extraction solvent, specifically, the extraction solvent to a position close to the upper surface of the coffee granule layer, and then it is kept still for a certain time. Then, after a predetermined time has elapsed, the liquid supply valve 57A is opened, and the extract is discharged to the storage tank 56. At this time, the extract contained in the coffee granules M passes through the coffee granules M before reaching the discharge opening 52B '. For this reason, a bitter taste component is adsorbed by the coffee granules M, and a refreshing coffee extract is obtained.

  FIG. 4 shows a modification of the coffee brewing apparatus 1 disclosed in FIG. 3 and shows an example in which the injection means is connected to the lower side wall of the granule container 52. By connecting the injection means to the lower side wall, the extraction solvent is injected substantially from the lower part of the coffee granule M into the granule container 52. Thereafter, the liquid feeding valve 57 is opened, so that the extracted liquid extracted from the coffee is discharged to the storage tank 56. At that time, since the extract passes through the coffee granules M, the bitter component is removed.

  Here, the coffee granule used as an extraction raw material is explained in full detail. The coffee granule used in the present invention may be any granule obtained by pulverizing roasted coffee beans. The cultivated tree species of coffee beans is not particularly limited, and examples thereof include Arabica species and Robusta species. The method of the present invention is characterized in that a coffee extract with a clear aftertaste and a distinctive personality can be obtained even if it is deeply drunk. Species are preferably used. The variety is not particularly limited, and examples thereof include mocha, Brazil, Colombia, Guatemala, Blue Mountain, Kona, Mandelin, Kilimanjaro, and the like. A plurality of types of coffee beans may be blended.

  The degree of roasting (usually expressed in the order of light roasting, medium roasting and deep roasting) is not particularly limited. In general, roasted coffee beans cannot exhibit the rich personality of the coffee beans themselves if they are shallowly roasted, and there is little scorching odor due to roasting, but the heating has not progressed to the inside of the beans and sour taste and sourness However, if roasting is deep, the burning odor will increase on the surface, but the unique bitterness of coffee caused by roasting and the aroma that rises from it will be obtained, and it will be an attractive flavor. Are known. From the viewpoint of maximizing the characteristics of the present invention that a coffee extract with distinctive individuality with reduced burnt bitterness can be obtained, it is preferable to perform roasting to the extent of medium roasting or deep roasting. In terms of L value, L value of 15 to 24 is preferable, 16 to 22 is more preferable, and 16 to 20 is particularly preferable. Here, the L value is a numerical value of the surface color of the coffee granules obtained by pulverizing roasted coffee beans, and is a value serving as a lightness index (0 is black, 100 is white). The L value of the coffee granules can be measured using, for example, a color difference meter. When this deep roasted coffee bean is used, there is also an advantage that the extraction efficiency of nutrient components is improved.

  The degree of grinding of roasted coffee beans (usually classified into coarse grinding, medium grinding, fine grinding, etc.) is not particularly limited, and ground beans with various particle size distributions can be used. If it is too small, clogging is likely to occur, and extraction may take time and may cause over-extraction, so that intermediate grinding and / or coarse grinding is one of the preferred embodiments of the present invention. The average particle size after pulverization is preferably about 0.1 to 2.0 mm, more preferably 0.5 to 2.0 mm, and particularly preferably 1.0 to 1.5 mm. As used herein, the term “overextraction” refers to a phenomenon in which an agglomerate, astringency, and miscellaneous taste inside a coffee bean are extracted when an extraction solvent is excessively brought into contact with coffee granules.

EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these.
A cylindrical extraction column (inner diameter: 50 mm) was used as the extraction device. A 100-mesh metal filter was placed at the bottom of the column extraction unit, and 100 g of coffee granules (average particle size of 1 to 2 mm) crushed from Arabica roasted coffee beans (L = 20) were added thereto. In order to keep the coffee granules stationary, a 100 mesh metal filter was placed on top of the coffee granules and fixed. 200 g of pure water at 98 ° C. was added from the upper part of the extraction column, and the extract was recovered from the lower part of the extraction column after being held still for 10 minutes with the valve at the lower part of the column closed (this product; extract A) ).

  For comparison, a 1L beaker made of stainless steel (diameter: 105 mm) was used, and 100 g of crushed coffee beans (coffee granules) of the same Arabica roasted coffee beans (L = 20) as described above were added, and further 200 g of pure water at 98 ° C. was added. The mixture was added and held for 10 minutes while stirring with a stirrer (200 rpm), and then the solid-liquid separation was performed with a 100 mesh metal filter to obtain an extract (Comparative Example: Extract B).

  About the extract A obtained by the manufacturing method of this invention and the comparative example (extract B), dilution adjustment was carried out so that soluble solid content might be 2%, and the sensory test was done by five special panels. Evaluation was made into the relative evaluation which made the evaluation point of the comparative example (extract B) 3 points about the item of bitterness, aroma, and miscellaneousness (bitterness: the higher the score, the weaker the bitterness, the aroma: the higher the score) The stronger the aroma (good), the miscellaneous taste: the higher the score, the weaker the mischief).

  The results are shown in Table 1. It has been clarified that the production method of the present invention can reduce excessive bitterness and miscellaneous taste while maintaining the preferred flavor components. Extract A was a coffee extract with a good balance of sourness, bitterness, and richness, and all expert panels evaluated that palatability was higher than Extract B.

  The production method of the present invention provides a method for producing a coffee extract that can selectively reduce excessive bitterness while maintaining the preferred coffee flavor components. The coffee extract obtained by the production method of the present invention is a coffee extract with balanced acidity, bitterness, and richness.

Claims (4)

  In the production of a coffee extract by passing a solvent through a coffee granule layer and recovering the extract, a method for producing a coffee extract comprising a step of retaining a solvent in a coffee granule layer that is allowed to stand in a substantially sealed state .   The method according to claim 1, wherein the amount of solvent is 0.3 to 2 times the volume of coffee granules.   The method according to claim 1 or 2, wherein the retention time of the solvent in the coffee granule layer is 5 to 60 minutes.   The method according to claim 1, wherein a column type extractor is used.