Method for producing processed coffee, processed coffee, enzyme agent, and method for reducing coffee residue

Abstract

The purpose of the present invention is to provide a coffee beverage having reduced residue and improved taste. The present invention relates to a method for producing processed coffee, the method including causing at least one selected from the group consisting of tannase, pectinase, and protease to act on coffee. The present invention also relates to an enzyme agent for reducing coffee residue, the enzyme agent containing at least one selected from the group consisting of tannase, pectinase, and protease.

Description

Processed coffee production method, processed coffee, enzyme preparation, and coffee residue reduction method

[0001] The present invention relates to a processed coffee production method, processed coffee, an enzyme preparation, and a coffee residue reduction method.

[0002] Coffee is one of the most consumed beverages in the world, and its market size continues to expand year by year. In recent years, along with the diversification of consumer preferences, development of various products has been demanded.

[0003] In the extraction step and filtration treatment step of a coffee beverage production process, addition of various enzymes has been studied for enhancing the amount of components in an extract and improving filterability. For example, Patent Document 1 discloses a method for producing a coffee beverage or powdered instant coffee by allowing tannase to act on an extract of roasted coffee beans and then using this liquid. Patent Document 2 discloses a method of allowing a fibrinolytic enzyme to act for the purpose of preventing the occurrence of turbidity while maintaining the flavor of a coffee extract. Patent Document 2 discloses a treatment method using a complex enzyme preparation such as Viscozyme composed of arabanase, β-glucanase, hemicellulase and the like. Patent Document 3 discloses a method for producing a coffee extract including a step of treating with a coffee extract and a polysaccharide-degrading enzyme. Patent Document 3 discloses a treatment method using a cellulolytic enzyme, a hemicellulolytic enzyme and pectinase for the purpose of improving the yield of soluble solids derived from coffee beans. Patent Document 4 discloses a production method combining treatment with tannase and adsorbent treatment for the purpose of suppressing bitter and astringent taste while maintaining the richness and flavor of a coffee extract. In addition, Patent Document 5 discloses a natural edible antioxidant having an extract obtained by enzymatic decomposition of green coffee beans as an active ingredient. In Patent Document 5, an extract having antioxidant activity is obtained by treating green coffee bean powder with cellulase and then further treating with an acidic protease.

[0004] Japanese Patent Application Laid-Open No. 51-44668, Japanese Patent Application Laid-Open No. 4-45745, Japanese Patent No. 5833841, Japanese Patent No. 3691453, Japanese Patent Application Laid-Open No. 58-138347

[0005] As mentioned above, methods for enzymatically treating coffee liquid or coffee beans have been disclosed. However, conventional techniques sometimes leave residues in the coffee liquid that cannot be removed by filtration, and improvements have been needed. Furthermore, with the diversification of consumer preferences, there is a demand for improved taste, but enzymatic improvement of coffee flavor is insufficient, and further improvements are needed.

[0006] Therefore, the present invention aims to provide a coffee beverage in which the amount of residue in the coffee liquid is reduced and the taste is improved.

[0007] Specifically, the present invention has the following configuration.

[0008] [1] A method for producing processed coffee, comprising reacting coffee with at least one selected from the group consisting of tannase, pectinase, and protease. [2] The method for producing processed coffee according to [1], wherein the protease is a neutral protease or an alkaline protease. [3] The method for producing processed coffee according to [1] or [2], wherein the protease is a protease derived from the genus Bacillus or the genus Geobacillus. [4] The method for producing processed coffee according to any one of [1] to [3], wherein the tannase is a tannase derived from the genus Aspergillus. [5] The method for producing processed coffee according to any one of [1] to [4], wherein the pectinase is a pectinase derived from the genus Aspergillus. [6] Processed coffee produced by the method according to any one of [1] to [5]. [7] An enzyme preparation for reducing coffee residue, comprising at least one selected from the group consisting of tannase, pectinase, and protease. [8] The enzyme preparation according to [7], wherein the protease is a neutral protease or an alkaline protease. [9] The enzyme preparation according to [7] or [8], wherein the protease is a protease derived from the genus Bacillus or the genus Geobacillus.

[10] The enzyme preparation according to any one of [7] to [9], wherein the tannase is a tannase derived from the genus Aspergillus.

[11] The enzyme preparation according to any one of [7] to

[10] , wherein the pectinase is a pectinase derived from the genus Aspergillus.

[12] A method for reducing coffee residue, comprising treating coffee with at least one selected from the group consisting of tannase, pectinase, and protease.

[13] The method for reducing coffee residue according to

[12] , wherein the protease is a neutral protease or an alkaline protease.

[14] The method for reducing coffee residue according to

[12] or

[13] , wherein the protease is a protease derived from the genus Bacillus or the genus Geobacillus.

[15] The method for reducing coffee residue according to any one of

[12] to

[14] , wherein the tannase is a tannase derived from the genus Aspergillus.

[16] The method for reducing coffee residue according to any one of

[12] to

[15] , wherein the pectinase is a pectinase derived from the genus Aspergillus.

[0009] Furthermore, the present invention has the following configuration:

[101] A method for improving the taste of coffee, comprising treating coffee with at least one selected from the group consisting of tannase, pectinase, and protease.

[102] The method for improving the taste of coffee according to

[101] , wherein the protease is a neutral protease or an alkaline protease.

[103] The method for improving the taste of coffee according to

[101] or

[102] , wherein the protease is a protease derived from the genus Bacillus or the genus Geobacillus.

[104] The method for improving the taste of coffee according to any one of

[101] to

[103] , wherein the tannase is a tannase derived from the genus Aspergillus.

[105] The method for improving the taste of coffee according to any one of

[101] to

[104] , wherein the pectinase is a pectinase derived from the genus Aspergillus.

[106] A method for improving the acidity of coffee, comprising acting on coffee with pectinase.

[107] The method for improving the acidity of coffee according to

[106] , wherein the pectinase is a pectinase derived from the genus Aspergillus.

[0010] According to the present invention, it is possible to provide a coffee beverage in which the amount of residue in the coffee liquid is reduced and the taste is improved.

[0011] The present invention will be described in detail below. The following descriptions of constituent elements may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, numerical ranges expressed using "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits.

[0012] (Method for producing processed coffee / Method for reducing coffee residue) This embodiment relates to a method for producing processed coffee, which includes treating coffee with at least one selected from the group consisting of tannase, pectinase, and protease. This embodiment also relates to a method for reducing coffee residue, which includes treating coffee with at least one selected from the group consisting of tannase, pectinase, and protease.

[0013] In this embodiment, processed coffee with reduced residue can be obtained by treating coffee with at least one enzyme selected from the group consisting of tannase, pectinase, and protease. The residue in processed coffee refers to the precipitate obtained when the processed coffee, after enzyme treatment, is subjected to centrifugation (5000 rpm, 10 minutes). In this embodiment, the residue that was suspended or settled in the coffee liquid is dissolved by the enzyme treatment described above, thus reducing the amount of residue in the processed coffee. Reducing the residue in processed coffee improves the texture and mouthfeel of the processed coffee, and also reduces off-flavors. Furthermore, in this embodiment, if coffee raw materials such as ground coffee beans are dispersed or settled in the coffee, it is also possible to reduce the amount of waste derived from these coffee raw materials.

[0014] Furthermore, in this embodiment, processed coffee with improved flavor can be obtained by treating coffee with at least one selected from the group consisting of tannase, pectinase, and protease. In the processed coffee obtained in this embodiment, multiple taste qualities such as bitterness, sourness, and sweetness can be altered. For example, by treating coffee with pectinase or tannase, the sourness of the processed coffee can be improved, and by treating it with protease, the saltiness and umami of the processed coffee can be improved.

[0015] In this embodiment, two or more enzymes selected from the group consisting of tannase, pectinase, and protease may be applied to the coffee, but it is preferable to apply only one of tannase, pectinase, or protease. In other words, in this embodiment, it is preferable to apply a single enzyme to the coffee.

[0016] One embodiment of the method for producing processed coffee or reducing coffee residue according to this embodiment includes the following steps (1) and (2). An enzyme inactivation step may be added after step (2). (1) A step of preparing coffee. (2) A step of treating the prepared coffee with an enzyme preparation containing at least one selected from the group consisting of tannase, pectinase, and protease.

[0017] The coffee prepared in step (1) above is liquid or semi-liquid coffee. For example, coffee can be an extract obtained by extracting coffee raw materials (green coffee beans, roasted coffee beans, or ground coffee beans) with water (including hot water or steam), or a concentrate obtained by concentrating the extract. The concentrate may be a semi-liquid substance such as a paste obtained by concentrating coffee. The coffee may also be instant coffee, which is made by dissolving the dried extract or concentrate (such as instant coffee powder) in water (including hot water or steam). Furthermore, coffee may also include a slurry in which coffee raw materials are dispersed, or a solution in which the coffee raw materials have settled.

[0018] In particular, the coffee in this embodiment is preferably green coffee beans, roasted coffee beans, or an extract of these ground coffee beans. The type of coffee beans used is not particularly limited, and examples of cultivated tree species include Arabica, Robusta, and Liberica, while examples of coffee varieties include Mocha, Brazil, Colombia, Guatemala, Blue Mountain, Kona, Mandheling, and Kilimanjaro. One type of coffee bean may be used, or a blend of multiple types may be used. In this embodiment, it is preferable to roast the coffee beans to make roasted coffee beans, and the coffee is preferably an extract of roasted coffee beans.

[0019] The moisture content of the coffee is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 99% by mass or more.

[0020] The pH of coffee is, for example, pH 3.0 to 7.0, preferably pH 3.5 to 6.5, more preferably pH 4.0 to 6.0, and even more preferably pH 4.2 to 5.0.

[0021] The reaction time, temperature, and pH of the reaction solution for reacting the enzyme with coffee are not particularly limited. The reaction temperature is, for example, 15 to 75°C, preferably 20 to 60°C, more preferably 25 to 55°C, even more preferably 30 to 55°C, and even more preferably 40 to 55°C. The pH of the reaction solution is, for example, 3.0 to 10.0, preferably 3.0 to 7.0, and more preferably 4.0 to 7.0. The reaction time is, for example, 1 minute to 24 hours, preferably 2 minutes to 12 hours, and more preferably 10 minutes to 6 hours. The amount of residue in the processed coffee is reduced under these reaction conditions. These reaction conditions can be selected according to the coffee raw material. The optimal reaction conditions can be determined by preliminary experiments.

[0022] <Tanase> Tanase is an enzyme that hydrolyzes tannins. In the method for producing processed coffee according to this embodiment, tanase promotes the breakdown of plant cell walls derived from coffee beans, and as a result, the amount of residue contained in the processed coffee can be reduced. Furthermore, by applying tanase to coffee, the bitterness of the processed coffee can be reduced and the acidity can be improved.

[0023] The organism from which the tannase used in this embodiment is derived is not particularly limited, and examples include microorganisms such as filamentous fungi. The tannase derived from filamentous fungi is not particularly limited, but examples include tannases derived from the genera Aspergillus, Rhizopus, Mucor, Neurospora, Penicillium, Rhizomucor, and Sclerotinia.

[0024] In particular, tannases derived from the genus Aspergillus are preferred. Examples of tannases derived from the genus Aspergillus include those derived from Aspergillus oryzae, Aspergillus meleus, Aspergillus niger, Aspergillus sojae, Aspergillus luchuensis, and Aspergillus flavus.

[0025] In this embodiment, one type of tannase may be used alone, or multiple types may be used in combination. Among the above tannases, from the viewpoint of further improving the effect, a tannase derived from filamentous fungi is preferred, a tannase derived from the genus Aspergillus is more preferred, and a tannase derived from Aspergillus oryzae is even more preferred.

[0026] Tannase can be prepared from the culture medium of the microorganism from which the above-mentioned tannase originates. Specific preparation methods include recovering tannase from the culture medium or cells of the above-mentioned microorganism. For example, when using tannase-secreting microorganisms, the cells can be recovered from the culture medium by filtration, centrifugation, etc., as needed, and then the enzyme can be separated and / or purified. When using non-tannase-secreting microorganisms, the cells can be recovered from the culture medium by filtration, centrifugation, etc., as needed, and then the cells can be crushed by pressurization, sonication, etc., to expose the enzyme, and then the enzyme can be separated and / or purified. Methods for separating and / or purifying the enzyme can be any known protein separation and / or purification method without particular limitation, such as centrifugation, UF concentration, salting out, and various chromatography methods using ion exchange resins. The separated and / or purified enzyme can be powdered by drying methods such as freeze-drying or vacuum drying, and can also be powdered using appropriate excipients and / or drying aids in the drying method. Furthermore, the separated and / or purified enzyme can be liquefied by adding appropriate additives and sterilizing by filtration. Furthermore, in this embodiment, a commercially available product can also be used as the tannase. Examples of commercially available tannases include a tannase preparation derived from Aspergillus oryzae manufactured by Amano Enzyme Co., Ltd.

[0027] The amount of tannase used is not particularly limited, but for example, 0.01 U or more per 1 ml of coffee is used. From the viewpoint of further enhancing the residue reduction effect, the amount of tannase used per 1 ml of coffee is preferably 0.1 U or more, more preferably 0.5 U or more, even more preferably 1 U or more, even more preferably 3 U or more, even more preferably 5 U or more, and even more preferably 6 U or more. The upper limit of the range of tannase used per 1 ml of coffee is not particularly limited, but for example, it can be 100 U or less, 90 U or less, 80 U or less, 70 U or less, 60 U or less, 50 U or less, 40 U or less, 30 U or less, 20 U or less, 15 U or less, or 10 U or less. By appropriately adjusting the amount of tannase used, for example, the acidity of processed coffee can also be changed.

[0028] Tannase activity is defined as the amount of enzyme that degrades 1 μmol of depsid bonds from tannic acid per minute when reacting a 0.32% (w / v) tannic acid solution (pH 5.5, 0.05 mol / L citrate buffer) as a substrate at 30°C, with 1 unit (1 U) being defined. Activity is calculated by measuring the absorbance of the freed galloyl group at 310 nm. More specifically, tannase activity can be measured by the method described in the examples.

[0029] <Pectinase> Pectinase is an enzyme that hydrolyzes pectin. In the method for producing processed coffee of this embodiment, pectinase promotes the breakdown of plant cell walls derived from coffee beans, and as a result, the amount of residue contained in the processed coffee can be reduced. In addition, by applying pectinase to coffee, the acidity of the processed coffee can be improved.

[0030] The organism from which the pectinase used in this embodiment is derived is not particularly limited, and examples include microorganisms such as filamentous fungi. The pectinase derived from filamentous fungi is not particularly limited, but examples include pectinases derived from the genera Aspergillus, Rhizopus, Mucor, Neurospora, Penicillium, Rhizomucor, Sclerotinia, etc.

[0031] In particular, the pectinase is preferably a pectinase derived from the genus Aspergillus. Examples of pectinases derived from the genus Aspergillus include those derived from Aspergillus oryzae, Aspergillus meleus, Aspergillus niger, Aspergillus sojae, Aspergillus luchuensis, and Aspergillus flavus.

[0032] In this embodiment, the above-mentioned pectinase may be used individually or in combination of multiple types. Among the above-mentioned pectinases, from the viewpoint of further improving the effect, pectinase derived from filamentous fungi is preferred, more preferably pectinase derived from the genus Aspergillus is preferred, and even more preferably pectinase derived from Aspergillus niger is preferred.

[0033] Pectinase can be prepared from the culture medium of the microorganism from which the above-mentioned pectinase originates. Specific preparation methods include recovering pectinase from the culture medium or cells of the above-mentioned microorganism. For example, when using pectinase-secreting microorganisms, the cells can be recovered from the culture medium by filtration, centrifugation, etc., as needed, and then the enzyme can be separated and / or purified. When using non-pectinase-secreting microorganisms, the cells can be recovered from the culture medium by filtration, centrifugation, etc., as needed, and then the cells can be crushed by pressurization, sonication, etc., to expose the enzyme, and then the enzyme can be separated and / or purified. As for the enzyme separation and / or purification method, any known protein separation and / or purification method can be used without particular limitation, such as centrifugation, UF concentration, salting out, and various chromatography methods using ion exchange resins. The separated and / or purified enzyme can be powdered by drying methods such as freeze-drying or vacuum drying, and can also be powdered using appropriate excipients and / or drying aids in the drying method. Furthermore, the separated and / or purified enzyme can be liquefied by adding appropriate additives and sterilizing by filtration. In addition, a commercially available product can be used as pectinase in this embodiment. Examples of commercially available pectinases include the Aspergillus niger-derived pectinase preparation manufactured by Amano Enzyme Co., Ltd.

[0034] The amount of pectinase used is not particularly limited, but for example, 0.01 U or more per 1 ml of coffee is used. From the viewpoint of further enhancing the residue reduction effect, the amount of pectinase used per 1 ml of coffee is preferably 0.1 U or more, more preferably 1 U or more, even more preferably 2 U or more, even more preferably 5 U or more, even more preferably 10 U or more, and even more preferably 15 U or more. The upper limit of the range of pectinase used per 1 ml of coffee is not particularly limited, but for example, it can be 1000 U or less, 900 U or less, 800 U or less, 700 U or less, 600 U or less, 500 U or less, 400 U or less, 300 U or less, 200 U or less, 100 U or less, 80 U or less, 50 U or less, or 30 U or less. By appropriately adjusting the amount of pectinase used, it is also possible to change, for example, the acidity or bitterness of processed coffee.

[0035] Pectinase activity is defined as the amount of enzyme that reduces the viscosity of a 0.7% (w / v) LM pectin solution (pH 3.5 McIlbein buffer) by 50% per minute when reacted at 40°C. One unit (1 U) of enzyme is defined as the amount of enzyme that reduces the viscosity of the solution by 50% per minute. The activity is calculated from the viscosity reduction rate by measuring the flow time of the reaction solution using an Ostwald viscometer. More specifically, pectinase activity can be measured by the method described in the examples.

[0036] <Protease> Protease is an enzyme that hydrolyzes proteins. In the method for producing processed coffee of this embodiment, protease promotes the breakdown of proteins derived from coffee beans, and as a result, the amount of residue contained in the processed coffee can be reduced.

[0037] The organism from which the protease used in this embodiment is derived is not particularly limited, and examples include microorganisms such as bacteria. While there are no particular limitations on bacterial-derived proteases, examples include proteases derived from the genera Bacillus and Geobacillus.

[0038] Specific examples of proteases derived from the genera Bacillus or Geobacillus include proteases derived from Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus stearothermophilus, Bacillus subtilis, and Geobacillus stearothermophilus.

[0039] The type of protease is not particularly limited; for example, acidic proteases (aspartic acid proteases), neutral proteases, alkaline proteases, etc. are examples. Among these, from the viewpoint of further improving the effects of the present invention, the protease is preferably a neutral protease or an alkaline protease, and is particularly preferably an alkaline protease.

[0040] In this embodiment, the above-mentioned proteases may be used individually or in combination of multiple types. Among the above-mentioned proteases, from the viewpoint of further improving the effect, bacterial proteases are preferred, more preferably proteases derived from the genus Bacillus or the genus Diobacillus, and even more preferably proteases derived from Bacillus licheniformis or Diobacillus stearothermophilus.

[0041] Proteases can be prepared from the culture medium of the microorganisms from which the proteases are derived. Specific preparation methods include recovering the protease from the culture medium or cells of the microorganisms. For example, when using protease-secreting microorganisms, the cells can be recovered from the culture medium by filtration, centrifugation, etc., as needed, and then the enzyme can be separated and / or purified. When using non-protease-secreting microorganisms, the cells can be recovered from the culture medium by filtration, centrifugation, etc., as needed, and then the cells can be crushed by pressurization, sonication, etc., to expose the enzyme, and then the enzyme can be separated and / or purified. Methods for separating and / or purifying the enzyme can be any known protein separation and / or purification method without particular limitation, such as centrifugation, UF concentration, salting out, and various chromatography methods using ion exchange resins. The separated and / or purified enzyme can be powdered by drying methods such as freeze-drying or vacuum drying, and can also be powdered using appropriate excipients and / or drying aids in the drying method. Furthermore, the separated and / or purified enzymes can be liquefied by adding appropriate additives and sterilizing by filtration. In addition, in this embodiment, commercially available proteases can be used. Examples of commercially available proteases include protease preparations derived from Bacillus amyloricephaciens, Bacillus licheniformis, and Diobacillus stearothermophilus, all manufactured by Amano Enzyme Co., Ltd.

[0042] There is no particular limitation on the amount of protease used, and for example, 1 U or more per 1 ml of coffee can be mentioned. From the perspective of further enhancing the residue reduction effect, the amount of protease used per 1 ml of coffee is preferably 10 U or more, more preferably 50 U or more, still more preferably 100 U or more, even more preferably 300 U or more, still even more preferably 500 U or more, further still more preferably 700 U or more, and even further still more preferably 1000 U or more. There is no particular limitation on the upper limit of the range of the amount of protease used per 1 ml of coffee, and examples include 500000 U or less, 100000 U or less, 50000 U or less, 20000 U or less, 15000 U or less, 12000 U or less, 10000 U or less, 8000 U or less, 7000 U or less, 6000 U or less, or 5000 U or less. By appropriately adjusting the amount of protease used, for example, the salty taste and umami of processed coffee can be altered.

[0043] Protease activity is defined as follows: Using a 0.6% (w / v) casein solution (0.05 mol / L sodium hydrogen phosphate, pH 8.0) as a substrate, when reacted at 37°C for 10 minutes, the amount of enzyme that causes an increase in Folin reagent colored substance corresponding to 1 µg of tyrosine per minute is defined as 1 unit (1 U). The activity is calculated by measuring the absorbance at 660 nm using Folin reagent. More specifically, the protease activity can be measured by the method described in the Examples.

[0044] (Enzyme Preparation) This embodiment relates to an enzyme preparation for reducing coffee residue, comprising at least one selected from the group consisting of tannase, pectinase and protease. The enzyme preparation only needs to be a preparation comprising at least one selected from the group consisting of tannase, pectinase and protease, and may also be a preparation consisting of at least one selected from the group consisting of tannase, pectinase and protease. Furthermore, the enzyme preparation may be in any form of powder, solid, gel, or liquid.

[0045] As for the tannase, pectinase or protease contained in the enzyme preparation, the respective enzymes mentioned above can be cited, and preferred embodiments are also the same as those described above.

[0046] The enzyme agent of the present embodiment may contain two or more kinds selected from the group consisting of tannase, pectinase and protease, but it preferably contains only one kind of tannase, pectinase or protease. That is, the enzyme agent of the present embodiment is preferably a single enzyme agent.

[0047] Further, the enzyme agent may contain a carrier, and in this case, the enzyme in the enzyme agent may be immobilized on a carrier such as a porous body. In the immobilized enzyme, the enzyme and the carrier may be in a covalently bonded state, may be in an attracted state via electrostatic interaction, or may be in a state where the enzyme is encapsulated in a protein within the porous body. The carrier used for the immobilized enzyme is not particularly limited, but is preferably insoluble. The insoluble carrier may be either an inorganic substance or an organic substance.

[0048] In addition to the above enzymes, the enzyme agent may contain other components to an extent that does not affect the effects of the present invention. Examples of other components include enzymes other than the above, additives, and culture residues generated in the enzyme production process. Examples of the additives include excipients, buffers, suspending agents, stabilizers, preservatives, antiseptics, and physiological saline. Examples of the excipients include starch, dextrin, maltose, trehalose, lactose, D-glucose, sorbitol, D-mannitol, sucrose, and glycerol. Examples of the buffers include phosphates, citrates, and acetates. Examples of the stabilizers include propylene glycol and ascorbic acid. Examples of the preservatives include phenol, benzalkonium chloride, benzyl alcohol, chlorobutanol, and methylparaben. Examples of the antiseptics include ethanol, benzalkonium chloride, para-hydroxybenzoic acid, and chlorobutanol. These additives may be contained singly or in combination of two or more kinds.

[0049] (Processed Coffee) The present embodiment relates to processed coffee produced by the above-described method for producing processed coffee. The processed coffee contains an enzyme-treated product of some components of coffee, and in the present embodiment, the above-described enzymatic decomposition product may be contained therein.

[0050] In this embodiment, the coffee on which the enzyme is applied is preferably a water (including hot water or steam) extract. Therefore, the moisture content of the resulting processed coffee is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 99% by mass or more.

[0051] The pH of the processed coffee is, for example, pH 3.0 to 7.0, preferably pH 3.5 to 6.5, more preferably pH 4.0 to 6.0, and even more preferably pH 4.2 to 5.0. If the pH of the processed coffee is X and the pH of the coffee before enzyme treatment is Y, then it is preferable that X ≤ Y.

[0052] Furthermore, the term "processed coffee" in this specification also includes dried, solid processed coffee.

[0053] (Processed Coffee-Containing Beverage) This embodiment may also relate to a processed coffee-containing beverage containing the processed coffee described above. The processed coffee-containing beverage of this embodiment may contain optional ingredients as appropriate. For example, optional ingredients may include milk (animal milk, plant milk), flavorings, sweeteners, acidulants, bittering agents, colorings, antioxidants, pH adjusters, vitamins, amino acids, minerals, defoaming agents, emulsifiers (glycerin fatty acid esters, sucrose fatty acid esters, lecithin, saponins, etc.), thickening polysaccharides (pectin, carboxymethylcellulose, etc.), salts (sodium chloride, calcium salts, phosphates, etc.).

[0054] (Method for improving taste / method for improving acidity) This embodiment relates to a method for improving the taste of coffee, which includes applying at least one selected from the group consisting of tannase, pectinase, and protease to coffee. In the method for improving the taste of this embodiment, multiple taste qualities such as bitterness, acidity, and sweetness can be altered. For example, by applying pectinase to coffee, the bitterness and acidity of processed coffee can be improved. Also, by applying tannase to coffee, the bitterness of processed coffee can be reduced and the acidity can be improved. In other words, this embodiment may also relate to a method for improving the bitterness or acidity of coffee, which includes applying pectinase to coffee. Furthermore, this embodiment may also relate to a method for reducing the bitterness or improving the acidity of coffee, which includes applying tannase to coffee.

[0055] The features of the present invention will be further described in detail below with reference to examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below.

[0056] (Materials used)

[0057] (Method for measuring enzyme activity) <Method for measuring enzyme activity (method for measuring protease activity)> Protease activity was calculated using the following method based on the 9th edition of the Japanese Food Additives Compendium. 5 mL of 0.6% (w / v) casein solution (0.05 mol / L sodium hydrogen phosphate, pH 8.0) was heated at 37°C for 10 minutes, then 1 mL each of appropriately diluted sample solutions were added and immediately shaken. After letting this solution stand at 37°C for 10 minutes, 5 mL of trichloroacetic acid reagent (containing 1.8% (w / v) trichloroacetic acid, 1.8% (w / v) sodium acetate, and 0.33 mol / L acetic acid) was added and shaken, and the solution was again left at 37°C for 30 minutes and filtered. The first 3 mL of filtrate was removed, and the next 2 mL of filtrate was measured, 5 mL of 0.55 mol / L sodium carbonate reagent and 1 mL of forin reagent (1→3) were added, and the solution was shaken well and left at 37°C for 30 minutes. For this solution (enzyme reaction solution), the absorbance AT at a wavelength of 660 nm was measured using water as a control. Separately, 1 mL of the sample solution containing protease was weighed out, 5 mL of trichloroacetic acid reagent (containing 1.8% (w / v) trichloroacetic acid, 1.8% (w / v) sodium acetate, and 0.33 mol / L acetic acid) was added and shaken, then 5 mL of 0.6% (w / v) casein solution (0.05 mol / L sodium hydrogen phosphate, pH 8.0) was added and immediately shaken, and left to stand at 37°C for 30 minutes. For solutions (blank) prepared in the same manner as the enzyme reaction solution described above, the absorbance AB was measured. The amount of enzyme that produces an increase in the forin reagent colorant equivalent to 1 μg of tyrosine per minute was defined as 1 unit (1 U). 1 mL, 2 mL, 3 mL, or 4 mL of 1 mg / mL tyrosine standard stock solution (0.2 mol / L hydrochloric acid) were measured, and 0.2 mol / L hydrochloric acid reagent was added to each to make a total volume of 100 mL. 2 mL of each solution was measured, 5 mL of 0.55 mol / L sodium carbonate reagent and 1 mL of Forin reagent (1→3) were added, and the mixture was immediately shaken. The solutions were then left at 37°C for 30 minutes. The absorbances A1, A2, A3, and A4 at a wavelength of 660 nm were measured for these solutions. For control (blank solution), the solution obtained by measuring 2 mL of 0.2 mol / L hydrochloric acid reagent, adding 5 mL of 0.55 mol / L sodium carbonate reagent and 1 mL of Forin reagent (1→3), immediately shaking, and leaving it at 37°C for 30 minutes was used as a control (blank solution), and the same measurements were performed.A calibration curve was created by plotting the absorbances A1, A2, A3, and A4 on the vertical axis and the amount of tyrosine (μg) in 2 mL of each solution on the horizontal axis. The amount of tyrosine (μg) corresponding to an absorbance difference of 1 (slope of the calibration curve) was then determined. Protease activity (U / g, U / mL) = (AT - AB) × F × 1 1 / 2 × 1 / 10 × 1 / M AT: Absorbance of the enzyme reaction solution AB: Absorbance of the blank F: Amount of tyrosine (μg) when the absorbance difference is 1, as determined from the tyrosine calibration curve 1 1 / 2: Conversion factor to the total volume of solution after reaction cessation 1 / 10: Conversion factor to the reaction time per minute M: Dilution factor of the sample.

[0058] <Method for Measuring Pectinase Activity> Based on the 9th edition of the Japanese Food Additives Standards, pectinase activity was calculated using the following method. 6 mL of 0.7% (w / v) LM pectin solution (pH 3.5 McIlbine buffer) was heated at 40°C for 10 minutes, then 2 mL each of appropriately diluted sample solutions (each enzyme solution described later) were added, and the mixture was immediately shaken. This solution was placed vertically in a constant temperature water bath at 40 ± 0.5°C, and the time ti seconds required for the liquid level to flow from the upper mark to the lower mark on sphere B was measured. This procedure was repeated five times. Separately, the same procedure was performed using 6 mL of LM pectin solution (pH 3.5), 6 mL of McIlbine buffer (pH 3.5), and 2 mL of water, and the flow time t0 seconds was measured. Also, the same procedure was performed using 14 mL of water, and the flow time tw seconds was measured. The viscosity reduction rate was calculated using the following formula. A curve was drawn with the viscosity reduction rate on the vertical axis and time (Ti + ti / 2) seconds on the horizontal axis, and the time at which the viscosity reduction rate reached 50% was read. The amount of enzyme required to reduce viscosity by 50% per minute was defined as 1 unit (1 U). Viscosity reduction rate (V50) = ((t0 - ti) / (t0 - tw)) × 100 Pectinase activity (U / g, U / mL) = 60 / V50 × n ti: Flow time of 14 mL of reaction solution (seconds) t0: Flow time of 6 mL of substrate + 6 mL of buffer + 2 mL of water (seconds) tw: Flow time of 14 mL of water (seconds) 60: Unit conversion factor (1 minute = 60 seconds) n: Dilution factor of the sample

[0059] <Method for Measuring Tannase Activity> Based on the 9th edition of the Japanese Food Additives Compendium and Iibuchi et al. Agr. Bial. Chem., Vol. 31, No. 5, pp. 513-518, 1967, tannase activity was calculated using the following method. 4 mL of 0.32% (w / v) tannic acid solution (containing citrate buffer (0.05 mol / L) at pH 5.5) was heated at 30°C for 10 minutes, and then 1 mL of the sample solution, diluted as appropriate, was added to each and immediately shaken. This solution was heated at 30°C, and 1 mL of this solution was measured after 10 minutes and 20 minutes, diluted with 9 mL of water / ethanol (99.5%) mixture (1:4), and then further diluted 10-fold with the same mixture. For these solutions, the absorbance AT1 (10 min value) and AT2 (20 min value) at a wavelength of 310 nm were measured using a water / ethanol (99.5%) mixture (1:4) as a control. Separately, the absorbance AB1 (10 min value) and AB2 (20 min value) were measured using 1 mL of buffer solution instead of the sample solution in the same procedure, and the absorbance difference was determined. The tannase activity was calculated using the following formula from the literature Iibuchi et al. Agr. Bial. Chem., Vol. 31, No. 5, pp. 513-518, 1967. In the activity below, the amount of enzyme that degrades 1 μmol of depsid bonds per minute was defined as 1 unit (U). Tannase activity (U / g, U / mL) = 20.3 × 4 × (1 / 0.71) × (absorbance difference / Δt)

[0060] (Test Example 1) The coffee liquid (provided by Damin Group) was obtained by grinding coffee beans, extracting with hot water, filtering, and sterilizing. This coffee liquid was collected in a conical flask and adjusted to a temperature of 50°C. Each enzyme was added to the coffee liquid according to the conditions shown in the table below. A control sample without added enzymes was also prepared. The mixture was reacted at 50°C with stirring for 1 hour, and then heated in a boiling water bath for 10 minutes to inactivate the enzymes. The obtained sample was cooled to room temperature and centrifuged (5000 rpm, 10 minutes) to obtain a precipitate. The precipitation rate was calculated using the following formula. Sedimentation rate (%) = ((M2 - M0) / (M1 - M0)) × 100 M0: Mass of the centrifuge tube M1: Total mass of the centrifuge tube and coffee solution M2: Total mass of the precipitate and centrifuge tube after centrifugation In addition, the pH of the supernatant after centrifugation was measured, and sensory evaluation was performed on samples treated with tannase derived from Aspergillus oryzae.

[0061]

[0062] (Test Example 2) A commercially available coffee concentrate (manufactured by Jiangsu Huasang Food Technology Co.) was diluted with water to a Brix of 1.0%, and 300 mL was taken into each of three Erlenmeyer flasks. The first Erlenmeyer flask was placed in a constant temperature water bath set to 50°C, and tannase derived from Aspergillus oryzae was added to a concentration of 0.5 U / mL-coffee. The second Erlenmeyer flask was also placed in a constant temperature water bath set to 50°C, and pectinase derived from Aspergillus nigar was added to a concentration of 2.0 U / mL-coffee. A control sample without enzyme addition was also prepared. The mixtures were reacted at 50°C for 1 hour with stirring, and then heated in a boiling water bath for 10 minutes to inactivate the enzymes. The obtained samples were cooled to room temperature, transferred to containers numbered using random numbers, and subjected to sensory evaluation. Evaluation by five panelists (n=3) revealed that in the samples treated with tannase, a change in taste was observed before and after treatment, mainly with an increase in acidity. Evaluation by four panelists (n=3) revealed that in the samples treated with pectinase, a change in taste was observed before and after treatment, with an increase in bitterness and acidity.

Claims

1. A method for producing processed coffee, comprising treating coffee with at least one selected from the group consisting of tannase, pectinase, and protease.

2. The method for producing processed coffee according to claim 1, wherein the protease is a neutral protease or an alkaline protease.

3. The method for producing processed coffee according to claim 1, wherein the protease is a protease derived from the genus Bacillus or the genus Geobacillus.

4. The method for producing processed coffee according to claim 1, wherein the tannase is a tannase derived from the genus Aspergillus.

5. The method for producing processed coffee according to claim 1, wherein the pectinase is a pectinase derived from the genus Aspergillus.

6. Processed coffee produced by the manufacturing method described in any one of claims 1 to 5.

7. An enzyme preparation for reducing coffee residue, comprising at least one selected from the group consisting of tannase, pectinase, and protease.

8. The enzyme preparation according to claim 7, wherein the protease is a neutral protease or an alkaline protease.

9. The enzyme preparation according to claim 7, wherein the protease is a protease derived from the genus Bacillus or the genus Geobacillus.

10. The enzyme preparation according to claim 7, wherein the tannase is a tannase derived from the genus Aspergillus.

11. The enzyme preparation according to claim 7, wherein the pectinase is a pectinase derived from the genus Aspergillus.

12. A method for reducing coffee residue, comprising treating coffee with at least one selected from the group consisting of tannase, pectinase, and protease.

13. The method for reducing coffee residue according to claim 12, wherein the protease is a neutral protease or an alkaline protease.

14. The method for reducing coffee residue according to claim 12, wherein the protease is a protease derived from the genus Bacillus or the genus Geobacillus.

15. The method for reducing coffee residue according to claim 12, wherein the tannase is a tannase derived from the genus Aspergillus.

16. The method for reducing coffee residue according to claim 12, wherein the pectinase is a pectinase derived from the genus Aspergillus.

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