How roasted coffee beans are made

Abstract

To provide a method for making roasted coffee bean for obtaining a coffee extract with an enhanced sweet aroma, and a method for making coffee extract from roasted coffee bean made by the making method.SOLUTION: Provided are a roasted coffee bean making method characterized by roasting green coffee bean after subjecting to hydrolytic enzyme treatment, and a coffee extract making method characterized by having a step for obtaining a roasted coffee bean modified by the roasted coffee bean making method and a step for preparing a coffee extract containing soluble solid content of the roasted coffee bean.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing roasted coffee beans to obtain a coffee extract having an enhanced sweet aroma, and a method for producing a coffee extract from the roasted coffee beans produced by said method. [Background technology]

[0002] Coffee is a popular, everyday beverage, and many packaged beverages and instant coffees that can be consumed by dissolving in water or other liquids are available on the market. It is expected that the taste and aroma of packaged coffee beverages and instant coffee can be improved by using coffee extracts with better taste and aroma as a raw material. In particular, aroma is one of the important qualities of coffee, and by using roasted coffee beans with strong aroma components as a raw material, a coffee beverage with better taste can be produced.

[0003] On the other hand, linalool (3,7-dimethylocta-1,6-dien-3-ol) has a fruity floral scent and is one of the aroma components contained in coffee extract. By adding linalool to coffee extract, a highly palatable coffee beverage can be obtained (see, for example, Patent Document 1). Green coffee beans contain two types of linalool glycosides. These linalool glycosides have no scent, but in the process of roasting green coffee beans, these glycosides are decomposed to produce free linalool with a sweet scent (see, for example, Non-Patent Document 1). In addition, among linalool derivatives, linalool oxide (2-(2-hydroxy-2-propyl)-5-methyl-5-vinyltetrahydrofuran) is also known to be an aroma component with a sweet scent (Non-Patent Document 2). In addition, methyl salicylate, methyl benzoate, benzyl acetate, etc. are known as aroma components with a sweet fruity floral scent similar to linalool. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4711958 [Non-patent literature]

[0005] [Non-Patent Document 1] Weckerle et al.,European Food Research and Technology,2003,vol.216,p.6-10. [Non-Patent Document 2] Wust and Mosandl, European Food Research and Technology,1999, vol.209, p.3-11. [Non-Patent Document 3] Bera et al., Plant Science,2017, vol.256, p.25-38. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a method for producing roasted coffee beans to obtain a coffee extract having an enhanced sweet aroma, and a method for producing a coffee extract from the roasted coffee beans produced by the method. [Means for solving the problem]

[0007] As a result of intensive research aimed at solving the above-mentioned problems, the inventors have discovered that the content of free linalool can be increased by treating green coffee beans with a hydrolytic enzyme, in particular treatment with a glycosidase (EC 3.2.1.-) or protease (EC 3.4.-) before roasting, and that a coffee extract with an enhanced sweet aroma can be obtained by roasting the glycosidase- or protease-treated green coffee beans and extracting the resulting roasted coffee beans with hot water, thereby completing the present invention.

[0008] [1] A method for producing roasted coffee beans according to a first aspect of the present invention comprises:A method for producing roasted coffee beans to prepare a coffee extract, comprising the steps of: After the raw coffee beans are treated with hydrolytic enzymes, In an unsprouted state Roasting (However, this does not include cases where raw coffee beans are treated with hydrolases in the presence of pectin.) It is characterized by: [2] In the method for producing roasted coffee beans according to [1] above, the hydrolase treatment is preferably carried out by contacting green coffee beans with an aqueous hydrolase solution. [3] In the method for producing roasted coffee beans according to [1] or [2] above, it is preferable that the hydrolase treatment is carried out by mixing the green coffee beans with 10 parts by mass or more of an aqueous hydrolase solution per 100 parts by mass of the green coffee beans. [4] In the method for producing roasted coffee beans according to either [2] or [3] above, the aqueous hydrolase solution is preferably an aqueous solution of a hydrolase preparation. [5] In any of the methods for producing roasted coffee beans according to [1] to [4] above, the hydrolase is preferably one or more enzymes selected from the group consisting of glycosidases and proteases. [6] In the method for producing roasted coffee beans according to [5] above, it is preferable that the glycosidase is one or more selected from the group consisting of β-glucosidase, hemicellulase, pectinase, cellulase, and endo-1,4-xylanase. [7] A method for producing a coffee extract according to a second aspect of the present invention is characterized by comprising the steps of obtaining modified roasted coffee beans by any one of the methods for producing roasted coffee beans according to [1] to [6] above, and preparing a coffee extract containing soluble solids from the roasted coffee beans. [8] A third aspect of the present invention relates to a method for producing a coffee beverage, the method being characterized in that a coffee extract is produced by the method for producing a coffee extract according to the above [7], and then a coffee beverage is produced using the obtained coffee extract as a raw material. [9] A fourth aspect of the present invention relates to a method for producing an instant coffee beverage composition, the method being characterized in that a coffee extract is produced by the method for producing a coffee extract according to the above [7], and then an instant coffee beverage composition is produced using the obtained coffee extract as a raw material.

[10] A method for modifying roasted coffee beans according to a fifth aspect of the present invention comprises: 1. A method for modifying roasted coffee beans to prepare a coffee extract, comprising the steps of: After the raw coffee beans are treated with hydrolytic enzymes, In an unsprouted state Roasting (However, this does not include cases where raw coffee beans are treated with hydrolases in the presence of pectin.) It is characterized by: Effect of the Invention

[0009] The roasted coffee beans produced by the method for producing roasted coffee beans according to the present invention have a high content of linalool, which is a component of sweet aroma. Therefore, by using the coffee extract extracted from the roasted coffee beans obtained by the method as a raw material, it is possible to produce a coffee beverage or an instant coffee beverage composition with a strong sweet aroma. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 shows the measurement results of quantifying linalool glycoside 1 (Ara-Glc-LNL), linalool glycoside 2 (Api-Glc-LNL), and linalool (LNL) for green coffee beans treated under conditions A to C and untreated green coffee beans in Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In the present invention and this specification, the term "instant coffee beverage composition (IC beverage composition)" refers to a composition that can be dissolved or diluted in a liquid such as water, milk, etc. to prepare a coffee beverage. The IC beverage composition may be in the form of a powder or a liquid.

[0012] In the present invention and this specification, "powder" means a granular material (consisting of many solid particles with different size distributions, with some interaction between the individual particles). Also, "granules" are an aggregate of particles (granular granulated material) granulated from powder. Powder also includes granules.

[0013] <How roasted coffee beans are made> The method for producing roasted coffee beans according to the present invention is characterized in that green coffee beans are treated with a hydrolase and then roasted. Linalool glycosides are converted to linalool by the hydrolase treatment. By treating green coffee beans with a hydrolase, at least a part of the linalool glycosides in the green coffee beans are converted to linalool. Therefore, roasting the green coffee beans after the hydrolase treatment can provide roasted coffee beans with enhanced linalool. And, by using the roasted coffee beans with enhanced linalool as a raw material, a coffee extract with a high linalool content and a good sweet aroma can be obtained without adding linalool separately.

[0014] In addition, the hydrolase treatment also increases the contents of linalool oxide (CAS No.: 60047-17-8) and methyl salicylate (CAS No.: 119-36-8) in the green coffee beans. When the contents of linalool oxide and methyl salicylate in the coffee extract increase, the sweet aroma is enhanced. For this reason, roasting the green coffee beans after the hydrolase treatment can produce roasted coffee beans with increased contents of linalool oxide and methyl salicylate in addition to linalool. By using roasted coffee beans with increased contents of these components as a raw material, a coffee extract with a high content of these components and a good sweet aroma can be obtained without the need to add linalool oxide or methyl salicylate separately.

[0015] There are no particular limitations on the type or place of origin of the green coffee beans used as the raw material, and they may be Arabica, Robusta, or Liberica, or a blend of these.

[0016] The hydrolase used in the hydrolase treatment of green coffee beans is preferably an enzyme that hydrolyzes sugars or proteins, and more preferably a glycosidase (EC 3.2.1.-) or a protease (EC 3.4.-). The glycosidase used in the glycosidase treatment of green coffee beans is not particularly limited as long as it is an enzyme that has hydrolytic activity of glycosidic bonds. For example, β-glucosidase (EC 3.2.1.21), hemicellulase (EC 3.2.1.4), pectinase (EC 3.2.1.15), cellulase (endoglucanase (EC 3.2.1.4), cellobiohydrolase (EC 3.2.1.91)), endo-1,4-xylanase (EC 3.2.1.8), β-primeverosidase (EC 3.2.1.149), etc. can be used. The protease used in the protease treatment of green coffee beans is not particularly limited as long as it is an enzyme that has the activity of hydrolyzing peptide bonds. For example, it may be a proteinase that hydrolyzes peptide bonds within a molecule, or it may be an endopeptidase.

[0017] As the hydrolase such as glycosidase used in the present invention, for example, a commercially available hydrolase preparation can be used, or a recombinant hydrolase protein expressed by a microorganism or the like can be used. In the hydrolase treatment of green coffee beans, one type of hydrolase can be used, or two or more types of hydrolase can be used in combination. For example, in the glycosidase treatment of green coffee beans, one type of glycosidase can be used, or two or more types of glycosidase can be used in combination.

[0018] The hydrolase treatment, such as glycosidase treatment, of green coffee beans can be carried out, for example, by contacting the green coffee beans with an aqueous hydrolase solution, such as an aqueous glycosidase solution. The aqueous hydrolase solution can be prepared by dissolving the hydrolase in water or an edible buffer solution. Examples of edible buffer solutions include phosphate buffer and Tris buffer. The aqueous hydrolase solution used in the present invention is preferably a solution in which the hydrolase is dissolved in water, from the standpoint of the effect on the taste of the green coffee beans, and is preferably an aqueous glycosidase solution in which glycosidase is dissolved in water or an aqueous protease solution in which protease is dissolved in water.

[0019] The amount of hydrolase used in the hydrolase treatment such as glycosidase treatment is not particularly limited, and can be appropriately adjusted in consideration of the type of hydrolase used, the enzyme activity, the time and temperature of the enzyme reaction after contact with the green coffee beans, etc. In the present invention, in order to more efficiently convert the linalool glycoside in the green coffee beans to linalool, the amount of hydrolase used in the hydrolase treatment is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, even more preferably 0.1 to 2 parts by mass, even more preferably 0.5 to 1.0 parts by mass, and may be 0.1 to 0.5 parts by mass relative to 100 parts by mass of the green coffee beans.

[0020] The green coffee beans can be contacted with the aqueous hydrolase solution by mixing the green coffee beans with the aqueous hydrolase solution. There are no particular limitations on the amount of aqueous hydrolase solution to be mixed with the green coffee beans, but in order to allow the green coffee beans to uniformly and efficiently absorb the aqueous hydrolase solution, it is preferable to mix 10 parts by mass or more of the aqueous hydrolase solution per 100 parts by mass of green coffee beans, more preferably mix 30 to 200 parts by mass or more of the aqueous hydrolase solution, and even more preferably mix 70 to 100 parts by mass or more of the aqueous hydrolase solution.

[0021] After mixing the green coffee beans with the aqueous hydrolase solution, the mixture of the green coffee beans and the aqueous hydrolase solution is preferably maintained for a predetermined period of time at a temperature suitable for the enzymatic reaction of the hydrolase, in order to allow the green coffee beans to absorb the hydrolase and for the enzymatic reaction to occur subsequently. In addition, in order to allow the reaction to occur uniformly and efficiently for all of the green coffee beans in the mixture, it is also preferable to stir the mixture during the hydrolase reaction.

[0022] The temperature and time of the hydrolase reaction are appropriately adjusted in consideration of the amount of the hydrolase used and the green coffee beans to be treated. In order to obtain roasted coffee beans with a stronger linalool content, it is preferable to adjust the reaction conditions of the hydrolase reaction so that at least 1% by mass, preferably 10% by mass or more, more preferably 40% by mass or more of the total amount of linalool glycosides in the green coffee beans is converted to linalool. For example, since the higher the temperature, the higher the efficiency of the chemical reaction, in the present invention, it is preferable to carry out the hydrolase reaction by holding a mixture of green coffee beans and an aqueous solution of hydrolase at 30 to 80°C for 30 minutes to 120 hours, preferably 1 to 72 hours, more preferably 1 to 48 hours.

[0023] The green coffee beans after the hydrolase reaction may be subjected to a roasting treatment as they are, but it is preferable to dry them before subjecting them to a roasting treatment. The conditions for the drying treatment are not particularly limited, and either a fixed bed or a fluidized bed may be used.

[0024] The method for roasting the hydrolase-treated green coffee beans is not particularly limited, and may be any method generally used for roasting coffee beans, such as direct flame roasting, hot air roasting, far-infrared roasting, charcoal roasting, microwave roasting, etc. Furthermore, in addition to the hydrolase treatment, the green coffee beans may also be roasted after a known pre-roasting treatment, so long as the enhancing effect of linalool and the like by the hydrolase treatment is not impaired.

[0025] The roasted coffee beans produced by the method for producing roasted coffee beans according to the present invention can be used as a raw material for various foods and beverages, similar to roasted coffee beans produced by a conventional method. The production of various foods and beverages from the roasted coffee beans can be carried out by a conventional method.

[0026] <How to manufacture coffee extract> The method for producing a coffee extract according to the present invention is characterized in that the raw material is roasted coffee beans produced by the method for producing roasted coffee beans according to the present invention. This makes it possible to obtain a coffee extract having a high content of linalool, linalool oxide, and methyl salicylate per soluble solid content and an enhanced sweet aroma. That is, the method includes the steps of obtaining roasted coffee beans modified to have a high content of linalool, etc., and preparing a coffee extract containing the soluble solid content of the modified roasted coffee beans.

[0027] Since the extraction efficiency of the soluble solids is increased, it is preferable that the roasted coffee beans are ground before the soluble solids are extracted. The roasted coffee beans can be ground using a general grinding machine such as a roll mill. The degree of grinding is not particularly limited, and roasted coffee beans of various shapes such as coarse grinding, medium coarse grinding, medium grinding, medium fine grinding, and fine grinding can be used.

[0028] The coffee extract is obtained by contacting roasted coffee beans with heated water to extract soluble solids. The extraction method can be a method generally used for brewing coffee or a method used for extracting soluble solids from ground roasted coffee beans when producing instant coffee. Specifically, any of drip, espresso, siphon, percolator, coffee press (French press), high pressure extraction, continuous high pressure extraction, etc. may be used.

[0029] When two or more kinds of roasted coffee beans are used as raw materials, all of the roasted coffee beans used as raw materials may be modified to have a high content of linalool, etc., or only a portion of the roasted coffee beans used as raw materials may be modified to have a high content of linalool, etc. When two or more kinds of roasted coffee beans are used as raw materials, in the method for producing a coffee extract according to the present invention, a soluble solid content may be extracted from a mixture (bean blend) of two or more kinds of roasted coffee beans to prepare a coffee extract, or two or more kinds of coffee extracts obtained by separately extracting soluble solid content may be mixed to prepare a coffee extract.

[0030] The coffee extract produced by the method for producing a coffee extract according to the present invention is suitable as a raw material for coffee beverages and IC beverage compositions. By using a coffee extract with a high content of linalool and the like and an enhanced sweet aroma as a raw material, it is possible to obtain a coffee beverage or an IC beverage composition with a high content of linalool and the like and a strong sweet aroma without adding linalool or the like separately.

[0031] <How to make coffee drinks> Specifically, coffee beverages are sterilized either directly from the coffee extract used as a raw material, or after mixing with other raw materials depending on the product quality of the desired coffee beverage. The sterilization can be appropriately selected from sterilization processes that are commonly used in the production process of coffee beverages, such as heat sterilization, retort sterilization, and ultraviolet light sterilization. For example, the heat sterilization may be low-temperature sterilization at 100° C. or lower, or high-temperature sterilization at 100° C. or higher.

[0032] Coffee beverages are usually distributed on the market as packaged beverages sealed in containers. The containers and filling methods for filling the coffee beverages can be appropriately selected from those containers and filling methods commonly used in the manufacturing process of packaged coffee beverages. Examples of such containers include cans, plastic containers, paper containers, glass bottles, etc. Furthermore, filling into the containers may be performed in air or under a nitrogen gas atmosphere.

[0033] When producing a packaged coffee beverage, a pre-sterilized coffee beverage may be aseptically filled into a sterilized container and sealed, or a container filled with the coffee beverage and sealed may be subjected to a sterilization treatment, or hot-pack filling may be performed in which a heated coffee beverage is filled at a high temperature into a container and sealed.

[0034] In producing a coffee beverage, the coffee extract used as a raw material may be subjected in advance to various treatments such as concentration, dilution, and unnecessary matter removal. The coffee extract may be concentrated by a commonly used concentration method such as a thermal concentration method, a freeze concentration method, or a membrane concentration method using a reverse osmosis membrane or an ultrafiltration membrane. The unnecessary matter removal may be performed by a process generally used for removing insoluble matter from beverages, such as a filtration process or a centrifugation process. These treatments may also be performed on the coffee extract after other raw materials have been added and mixed.

[0035] In the production of coffee beverages, other ingredients that can be added to the coffee extract include ingredients that can be added to beverages, such as sweeteners, creaming powders (powders added to coffee and other beverages as a substitute for cream), dairy ingredients, flavorings, antioxidants, pH adjusters, thickeners, emulsifiers, etc.

[0036] Examples of sweeteners include sugars such as sugar, sucrose, oligosaccharides, glucose, and fructose, sugar alcohols such as sorbitol, maltitol, erythritol, xylitol, and reduced starch syrup, high-intensity sweeteners such as aspartame, acesulfame potassium, sucralose, neotame, advantame, and saccharin, stevia, etc. Sugar may be granulated sugar or powdered sugar.

[0037] Examples of dairy ingredients include whole milk powder, skim milk powder, whey powder, milk, low-fat milk, concentrated milk, skim concentrated milk, lactose, fresh cream, butter, etc. Note that whole milk powder and skim milk powder are obtained by removing moisture from milk (full fat milk) or skim milk by spray drying or the like, and then drying and powdering them.

[0038] Creaming powder can be produced by selecting edible oils and fats such as coconut oil, hardened coconut oil, palm oil, hydrogenated palm oil, palm kernel oil, hydrogenated palm kernel oil, soybean oil, corn oil, cottonseed oil, rapeseed oil, rice oil, safflower oil (safflower oil), sunflower oil, medium chain fatty acid triglyceride, milk fat, beef tallow, lard, etc.; carbohydrates such as sucrose, glucose, starch hydrolysate, etc.; other raw materials such as sodium caseinate, dibasic sodium phosphate, sodium citrate, skim milk powder, emulsifier, etc. according to the desired quality characteristics, dispersing them in water, homogenizing them, and drying them. Creaming powder can be produced, for example, by mixing raw materials including edible oils and fats in water, then forming an oil-in-water emulsion (O / W emulsion) using an emulsifier or the like, and then removing the water. As a method for removing water, any method can be selected, such as spray drying, spray freezing, freeze drying, freeze grinding, and extrusion granulation. The obtained creaming powder may be subjected to classification, granulation, pulverization, etc., as necessary.

[0039] Examples of the flavoring include coffee flavoring, milk flavoring, and the like.

[0040] Examples of antioxidants include vitamin C (ascorbic acid), vitamin E (tocopherol), BHT (dibutylhydroxytoluene), BHA (butylhydroxyanisole), sodium erythorbate, propyl gallate, sodium sulfite, sulfur dioxide, chlorogenic acid, and catechin.

[0041] Examples of pH adjusters include citric acid, succinic acid, acetic acid, lactic acid, malic acid, and tartaric acid, as well as organic acids such as gluconic acid, inorganic acids such as phosphoric acid, potassium carbonate, sodium hydrogen carbonate (sodium bicarbonate), and carbon dioxide.

[0042] Examples of the thickener include starch degradation products such as dextrin, saccharides such as maltose and trehalose, indigestible dextrin, dietary fibers such as pectin, guar gum, and carrageenan, and proteins such as casein.

[0043] Examples of the emulsifier include glycerin fatty acid ester-based emulsifiers such as monoglyceride, diglyceride, organic acid monoglyceride, and polyglycerin ester; sorbitan fatty acid ester-based emulsifiers such as sorbitan monostearate and sorbitan monooleate; propylene glycol fatty acid ester-based emulsifiers such as propylene glycol monostearate, propylene glycol monopalmitate, and propylene glycol oleate; sugar ester-based emulsifiers such as sucrose stearate, sucrose palmitate, and sucrose oleate; and lecithin-based emulsifiers such as lecithin and enzymatically decomposed lecithin.

[0044] The order of mixing other raw materials with the coffee extract is not particularly limited. All components may be added to the coffee extract and mixed simultaneously, or may be added sequentially and mixed.

[0045] <Method for producing a composition for IC beverage> In order to use it as a raw material for the composition for IC beverage, it is preferable to concentrate or powder the coffee extract in advance. Since the obtained composition for IC beverage has good storage stability, in the method for producing the composition for IC beverage according to the present invention, it is preferable to use a powdered coffee extract (instant coffee powder) as a raw material.

[0046] The concentration treatment of the coffee extract can be carried out in the same manner as the methods listed in the method for producing coffee beverages. The powdering of the coffee extract is obtained by drying the coffee extract. Examples of the drying method of the extract include freeze drying, spray drying, and vacuum drying. Further, the extract from coffee beans may be concentrated as necessary before drying.

[0047] The IC beverage composition is produced by mixing a concentrated coffee extract or powder with other ingredients. The order of mixing is not particularly limited, and all ingredients may be mixed simultaneously or sequentially.

[0048] When all the ingredients are in powder form, a powdered IC beverage composition is produced by mixing all the ingredients as they are, whereas when all the ingredients are in liquid form, a liquid IC beverage composition is produced by mixing all the ingredients as they are.

[0049] When powdered raw materials and liquid raw materials are used, the powdered raw materials are all mixed in advance, and the resulting mixed powder is sprayed with a liquid mixture of the raw materials and dried to produce a powdered IC beverage composition. Alternatively, a liquid IC beverage composition is produced by dissolving or dispersing the powdered raw materials in a liquid mixture of the raw materials.

[0050] When a concentrated coffee extract is used as a raw material, a liquid IC beverage composition is produced by adding other raw materials to the concentrated coffee extract and dissolving them. A liquid IC beverage composition can also be produced by producing a powdered IC beverage composition and then dissolving it in water, milk, or the like.

[0051] Other ingredients added to the IC beverage composition include sweeteners, creaming powders, dairy ingredients, flavorings, antioxidants, pH adjusters, thickeners, emulsifiers, excipients, binders, flow improvers (anti-caking agents), etc. As the sweeteners, creaming powders, dairy ingredients, flavorings, antioxidants, pH adjusters, thickeners, and emulsifiers, the same ones as those listed in the method for producing coffee beverages can be used.

[0052] Examples of the excipient and binder include starch hydrolysates such as dextrin, sugars such as maltose and trehalose, dietary fibers such as indigestible dextrin, proteins such as casein, etc. The excipient and binder are also used as carriers during granulation.

[0053] As the flow improver, processing preparations such as fine silicon oxide and tricalcium phosphate may be used.

[0054] The IC beverage composition of the present invention can be individually packaged in a small pouch or the like so that a single serving is consumed, or it can be packaged in a container such as a bottle so that several servings are consumed by shaking the beverage out of the container or taking it out with a spoon when used.

[0055] The individually packaged type is a stick-shaped aluminum pouch or a one-portion cup that is filled with the contents for one cup of coffee drink, and the contents can be taken out by opening the container and pushing it out with your fingers. The individually packaged type has the advantage of being easy to handle and hygienic, as each cup is sealed.

[0056] <Method for modifying the soluble solids content of green coffee beans> Linalool glycosides in green coffee beans can also be converted to linalool after being extracted from green coffee beans. For example, linalool glycosides are soluble solids and can be extracted from green coffee beans by hot water extraction. By subjecting a green coffee bean extract containing linalool glycosides to hydrolase treatment, at least a portion of the linalool glycosides in the extract is converted to linalool. For this reason, by extracting soluble solids from green coffee beans and subjecting the resulting extract to hydrolase treatment, the linalool in the soluble solids can be enhanced and modified. Linalool may be purified from the extract with enhanced linalool.

[0057] Extraction of soluble solids containing linalool glycosides from green coffee beans can be carried out in the same manner as preparation of coffee extract by hot water extraction from roasted coffee beans. In addition, hydrolase reaction of the obtained extract can be carried out in the same manner as the hydrolase reaction of green coffee beans. It is preferable to adjust the reaction conditions of hydrolase reaction so that at least 1% by mass or more, preferably 10% by mass or more, more preferably 40% by mass or more of the total amount of linalool glycosides in the extract is converted to linalool.

[0058] By treating the green coffee bean extract with a hydrolase, the contents of linalool oxide and methyl salicylate in the soluble solids of the green coffee beans can also be increased. The green coffee bean extract with increased contents of not only linalool but also linalool oxide and methyl salicylate is modified and has an enhanced sweet aroma. EXAMPLES

[0059] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to the following examples. In the following, unless otherwise specified, "%" means "% by mass".

[0060] [Reference example 1] Colombian Arabica beans were roasted, and linalool flavoring (0.02% alcohol dilution) was added to the resulting roasted coffee bean extract, and a sensory evaluation was performed on the sweet aroma. The sensory evaluation was performed by four trained expert panelists on a 5-point scale (1 being the weakest coffee-like sweet aroma, 5 being the strongest coffee-like sweet aroma), with the control being given a score of 1. The evaluation results are shown in Tables 1 and 2.

[0061] [Table 1]

[0062] [Table 2]

[0063] These results demonstrate that the addition of linalool enhances the sweet aroma, and that when the linalool concentration is 1 to 20 μg / 100 mL, and more preferably 2.5 to 5.5 μg / 100 mL, the sweet aroma characteristic of coffee is enhanced, resulting in a coffee extract that is highly palatable.

[0064] [Example 1] Ethiopian Arabica beans were treated with glycosidase, and the amounts of linalool glycosides and linalool in the resulting green coffee beans were quantified. Aromase H2 (Amano Enzyme Co., Ltd.), a commercially available β-glucosidase preparation, was used as the glycosidase.

[0065] First, 320 g of green coffee beans were mixed with 16 g of a β-glucosidase preparation (5 parts by mass per 100 parts by mass of green coffee beans) and an enzyme solution dissolved in 208 g of water, and the enzyme reaction was carried out at 45° C. for 48 hours while stirring at 3 rpm. Next, the green coffee beans after the enzyme reaction were dried at 60° C. for 18 hours (condition A).

[0066] For comparison, an enzyme solution prepared by dissolving a β-glucosidase preparation in water was treated at 70°C for 1 hour to inactivate the enzyme activity and then mixed with the green coffee beans. The procedure was the same as in Condition A, except that the beans were kept at 45°C for 48 hours with stirring at 3 rpm and then dried (Condition B).

[0067] In addition, the same procedure as in Condition A was followed, except that no β-glucosidase preparation was added and 320 g of raw coffee beans were mixed with 224 g of water, and the beans were then kept at 45°C for 48 hours with stirring at 3 rpm, and then dried (Condition C).

[0068] As a control, 320 g of green coffee beans were used (untreated).

[0069] For each green coffee bean, linalool glycoside 1 (Ara-Glc-LNL), linalool glycoside 2 (Api-Glc-LNL), and linalool (LNL) were quantified using the following method.

[0070] [Preparation of analytical samples] Approximately 100 mg of ground coffee beans was accurately weighed as an analytical sample into a screw - neck test tube, 0.4 mL of n - heptane was added, and it was shaken at 30 °C for 30 minutes. Then, 2 mL of pure water was added to the test tube and shaken for 3 hours. Next, the supernatant was sampled and filtered through a 0.45 - μm MF (micro - filtration), and then 0.1 mL each of the aqueous layer and the organic layer was aliquoted into an analytical vial. The aqueous layer was analyzed and quantified according to the linalool glycoside quantification method shown below, and the organic layer was analyzed and quantified according to the linalool quantification method shown below. All samples were prepared with N = 3 analytical samples, and the average value of the three analytical samples was taken as the quantified value.

[0071] [Linalool Quantification Method] In the subsequent experiments, the linalool in coffee beans was quantified by gas chromatography - FID method (GC - FID method).

[0072] <GC - FID Conditions> System: GC - 2010plus (manufactured by Shimadzu Corporation) Column: Rxi 5ms (0.25 μm, 0.25 mm ID × 30 m) Injection volume: 1 μL Vaporization chamber temperature: 260 °C Pressure: 65.8 kPa Total flow rate: 10.3 mL / min Column flow rate: 0.67 mL / min Column linear velocity: 19.4 cm / s Purge flow rate: 3.0 mL / min Split ratio: 10 Column oven temperature: 70 °C (held for 5 minutes) → 115 °C (5 °C / min) → 350 °C (25 °C / min, held for 10 minutes)

[0073] <Preparation of Linalool Standard Solution> Approximately 10 mg of the standard substance linalool (CAS: 78 - 70 - 6) was accurately weighed into a 20 - mL volumetric flask containing about 10 mL of n - heptane and made up to the mark with n - heptane. The resulting solution was diluted 1000 - fold, and this was used as the linalool standard solution.

[0074] [Quantification method of linalool glycoside] In the subsequent experiments, the linalool glycoside in coffee beans was quantified by liquid chromatography mass spectrometry (LC / MS method).

[0075] <LC / MS conditions: HPLC section> System: Prominence LC20A UFLC (manufactured by Shimadzu Corporation) Pump: LC-20AD Autosampler: SIL-20AC Detector: SPD-20A Column oven: CTO-20AC Degasser: DGU-20A3 Column: InertSustain C18 (3μm, 2.1mm ID × 250mm) Column oven temperature: 40°C Eluent flow rate: 0.2 mL / min Detection: UV 210nm Injection volume: 2μL Eluent composition: Solution A is 0.1% formic acid aqueous solution, and solution B is acetonitrile Gradient program: Table 3

[0076]

Table 3

[0077] <LC / MS conditions: MS section> System: LCMS-2020 Ionization method: Electrospray ionization (ESI(+ / -)) SIM: m / z 493(-) Molecular weight measurement range: m / z 50~1000 Dry gas temperature: 350°C Dry gas flow rate: 15L / min

[0078] <Preparation of linalool glycoside standard solution> Approximately 10 mg of the standard substance Linalyl-3-O-β-D-glucopyranosyl-(1-6)-α-L-arabinopyranoside (Ara-Glc-LNL) was accurately weighed into a 100 mL measuring flask and dissolved in pure water to make up to 100 mL. The prepared solution was diluted 200 times to prepare the Ara-Glc-LNL standard solution. Linalyl-3-O-β-D-glucopyranosyl-(1-6)-β-D-apiofuranoside (Api-Glc-LNL) was prepared in the same manner.

[0079] The quantitative results are shown in Figure 1. Treatment with the β-glucosidase preparation reduced the amount of linalool glycosides in green coffee beans and increased the amount of linalool.

[0080] [Example 2] Ethiopian Arabica beans were treated with glycosidase and the amount of linalool in the treated green coffee beans was examined. Aromase H2, a commercially available β-glucosidase preparation, was used as the glycosidase.

[0081] First, 10 g of green coffee beans was mixed with an enzyme solution prepared by dissolving 0.03 g of a β-glucosidase preparation (0.3 parts by mass per 100 parts by mass of green coffee beans) in the amount of water (proportion relative to the weight of the green coffee beans) shown in Table 4, and the enzyme reaction was carried out at 50°C for 48 hours while stirring at 3 rpm. Next, the green coffee beans after the enzyme reaction were dried at 60°C for 18 hours.

[0082] The amount of linalool in the obtained green beans was quantified in the same manner as in Example 1. The measurement results are shown in Table 4.

[0083] [Table 4]

[0084] As a result, it was found that the amount of linalool in the final coffee extract is affected by the amount of water used during glycosidase treatment, even though the amount of green beans and glycosidase are the same. It was confirmed that when the amount of water used during glycosidase treatment of green coffee beans is within the range of 10 to 90% by mass, the amount of linalool is high depending on the amount of water, and the linalool enhancing effect is high.

[0085] [Example 3] Green coffee beans were treated with various hydrolases, and the aroma components of the green coffee beans after treatment were quantified. Arabica beans from Ethiopia were used as the green coffee beans. The 10 types of hydrolases listed in Table 5 were used as the hydrolases.

[0086] [Table 5]

[0087] <Enzyme treatment> The green coffee beans were immersed in the aqueous solution of the enzyme preparation to carry out the enzyme treatment. Each aqueous solution of the enzyme preparation was adjusted so that the amount of enzyme relative to the green coffee beans was 0.5% or 1.0% by mass. The aqueous solution of the enzyme preparation adjusted so that the amount of enzyme relative to the green coffee beans was 0.5% by mass was prepared by mixing 50 mg of the enzyme and 7.95 g of ultrapure water in a 50 mL tube. The aqueous solution of the enzyme preparation adjusted so that the amount of enzyme relative to the green coffee beans was 1.0% by mass was prepared by mixing 100 mg of the enzyme and 7.90 g of ultrapure water in a 50 mL tube.

[0088] 10 g of green coffee beans were added to each 50 mL tube containing the aqueous enzyme preparation solution, and the beans were immersed in the solution and subjected to an enzyme reaction at 50°C for 48 hours while stirring at 3 rpm. The green coffee beans after the enzyme reaction were then dried at 60°C for 18 hours.

[0089] <Quantitative analysis of components in green coffee beans> The contents of linalool (LNL), trans-linalool oxide, and methyl salicylate were quantified for each type of green coffee bean. For comparison, the contents of untreated green coffee beans and green coffee beans that had been similarly soaked in ultrapure water that did not contain the enzyme preparation (water soaking treatment) were also quantified.

[0090] [Quantitative determination of linalool and methyl salicylate] The quantitative determination of linalool and methyl salicylate in green coffee beans was carried out by the following method.

[0091] <Standard solution adjustment> Approximately 10 mg of the standard substance linalool, the standard substance methyl salicylate, and the standard substance 2,3-dimethoxytoluene (CAS No.: 4463-33-6) were accurately weighed into a 100 mL volumetric flask, and the mixture was made up to 50:50 pentane:diethyl ether. The resulting solution was used as the standard solution.

[0092] <Pretreatment conditions> Approximately 21 g of boiling stones were placed in a 2 L mantle flask, and several drops of antifoaming agent were added using a Komagome pipette. Approximately 8 g of sample was weighed out and placed in the mantle flask, and 1 L of ultrapure water at room temperature was added. Furthermore, 1 mL of 2,3-dimethoxytoluene solution (a solution in which 2,3-dimethoxytoluene was dissolved in a mixed solvent of pentane:diethyl ether = 50:50 to give a concentration of approximately 25 mg / 100 mL) was added to the mantle flask as an internal standard substance, and the mixture was gently shaken. Separately, about 2 g of boiling stones and about 100 mL of a mixed solvent of pentane:diethyl ether=1:1 were placed in a 200 mL Erlenmeyer flask. Next, the mantle flask and the Erlenmeyer flask were set in an extractor, and then heated to boiling at the maximum output of the mantle heater for 20 minutes. After boiling, extraction was carried out for 90 minutes. After the extraction, the solvent was mixed with an appropriate amount of sodium sulfate to remove moisture, and then allowed to stand. The mixture was then transferred to a concentration tube by decantation and concentrated to 1 mL using a TurboVap (registered trademark) 500 (manufactured by Zymark Corporation).

[0093] <GC / MS Conditions> The concentrated sample was analyzed using GC / MS under the following conditions. GC section: 7890A (manufactured by Agilent Technologies) MS section: 5975C (manufactured by Agilent Technologies) Column: InertCap WAX-HT (0.25μm × 0.25mm × 60m) Injection volume: 1 μL Pressure: 50 psi Column flow rate: 1.737 mL / min Column linear velocity: 33.701 cm / sec Column oven temperature: 35°C (held for 1 minute) → 60°C (25°C / min) → 190°C (2°C / min) → 250°C (5°C / min, held for 26 minutes)

[0094] [Quantification of trans-Linalool Oxide] The quantification of trans-linalool oxide in green coffee beans was performed by the following method.

[0095] <Standard Solution Preparation> Approximately 10 mg of linalool oxide isomer mixture and 2,3-dimethoxytoluene were accurately weighed into a 100 mL volumetric flask and made up to the mark with a mixed solvent of pentane:diethyl ether = 50:50. The resulting solution was used as the standard solution.

[0096] When this standard solution was analyzed, three isomer peaks were obtained. The area values of each peak were taken, and considering that their detection sensitivities were similar, the area ratio was used as the abundance ratio to calculate the quantification value of trans-linalool oxide.

[0097] <Pretreatment Conditions> The pretreatment conditions were the same as those for the pretreatment of [Quantification of Linalool and Methyl Salicylate].

[0098] <GC / MS Conditions> The concentrated sample was analyzed using GC / MS under the following conditions. GC section: 7890B (manufactured by Agilent Technologies) MS: 5977A (Agilent Technologies) Column: InertCap WAX-HT (0.25 μm × 0.25 mm × 60 m) Injection volume: 1μL Pressure: 50psi Column flow rate: 2.5mL / min Column linear velocity: 33.693 cm / sec Column oven temperature: 35°C (1 min hold) → 60°C (25°C / min) → 190°C (2°C / min) → 250°C (5°C / min, 26 min hold)

[0099] The quantitative results of the content (μg / kg(GB)) of each component per 1 kg of green coffee beans (GB) are shown in Tables 6 to 8. Compared to untreated or water-soaked green coffee beans, the contents of linalool, linalool oxide, and methyl salicylate were all increased in green coffee beans treated with each hydrolase preparation. The increase in amount compared to untreated or water-soaked green coffee beans was greater for linalool than for linalool oxide and methyl salicylate.

[0100] [Table 6]

[0101] [Table 7]

[0102] [Table 8]

Claims

1. A method for producing roasted coffee beans for preparing a coffee extract, comprising treating green coffee beans with a hydrolase and then roasting the beans in an unsprouted state (excluding the case where the green coffee beans are treated with a hydrolase in the presence of pectin).

2. The method for producing roasted coffee beans according to claim 1 , wherein the hydrolase treatment is carried out by contacting green coffee beans with an aqueous hydrolase solution.

3. 3. The method for producing roasted coffee beans according to claim 1, wherein the hydrolase treatment is performed by mixing 10 parts by mass or more of an aqueous hydrolase solution per 100 parts by mass of the green coffee beans with the green coffee beans.

4. 4. The method of claim 2, wherein the aqueous hydrolase solution is an aqueous solution of a hydrolase preparation.

5. The method for producing roasted coffee beans according to any one of claims 1 to 4, wherein the hydrolase is one or more selected from the group consisting of glycosidases and proteases.

6. The method for producing roasted coffee beans according to claim 5, wherein the glycosidase is one or more selected from the group consisting of β-glucosidase, hemicellulase, pectinase, cellulase, and endo-1,4-xylanase.

7. A step of obtaining modified roasted coffee beans by the method for producing roasted coffee beans according to any one of claims 1 to 6; Preparing a coffee extract containing soluble solids from the roasted coffee beans; A method for producing a coffee extract, comprising the steps of:

8. A method for producing a coffee beverage, comprising producing a coffee extract by the method for producing a coffee extract according to claim 7, and then producing a coffee beverage using the resulting coffee extract as a raw material.

9. 8. A method for producing an instant coffee beverage composition, comprising the steps of: producing a coffee extract by the method for producing a coffee extract according to claim 7; and then producing an instant coffee beverage composition using the obtained coffee extract as a raw material.

10. A method for modifying roasted coffee beans for preparing a coffee extract, comprising treating the green coffee beans with a hydrolase and then roasting them in an unsprouted state (excluding the case where the green coffee beans are treated with a hydrolase in the presence of pectin).

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