Coffee extract production method and enzyme preparation

Abstract

The present invention aims to provide a method for producing a coffee extract that can further reduce the turbidity of the coffee extract. The method includes contacting the coffee extract with a glucoamylase having a glucoamylase activity of 32 U or less per 1g of coffee beans. Furthermore, the method includes contacting the coffee extract with a glucoamylase and a galactomannanase, wherein the glucoamylase has a glucoamylase activity of 0.24 U or greater per 1U of the galactomannanase activity.

Description

Technical Field

[0001] The present invention relates to a method for producing a coffee extract and an enzyme preparation. More specifically, the present invention relates to a method for producing a coffee extract with reduced turbidity and an enzyme preparation for reducing the turbidity of a coffee extract. Background Art

[0002] The turbidity of coffee extract reduces production efficiency due to adhesion of insoluble matter to equipment during the production process, and deteriorates the texture and flavor of the coffee extract during storage, thereby reducing its commercial value.

[0003] To prevent turbidity in coffee extracts, methods for enzymatically treating coffee extracts are known. For example, the following methods have been proposed: a method for preventing turbidity in a coffee extract, wherein a cellulolytic enzyme such as pectinase, cellulase, hemicellulase, arabinanase, or β-glucanase is allowed to act on the coffee extract before sterilization (Patent Document 1); a method for producing a coffee beverage, comprising treating a raw material component of a coffee beverage, including a coffee extract or a coffee dissolution, with an enzyme derived from a filamentous fungus (Aspergillus niger) having galactomannanase and acid protease activities (Patent Document 2); a method for producing concentrated coffee, comprising preparing a concentrated coffee liquid containing 5 to 35% by weight of solids and then adding a galactomannan degrading enzyme to the concentrated coffee liquid (Patent Document 3); and a method for producing a coffee beverage, comprising treating the coffee liquid with a galactomannan degrading enzyme (Patent Document 4).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 4-45745

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2002-272375

[0008] Patent Document 3: Japanese Patent Application Laid-Open No. 2002-330700

[0009] Patent Document 4: Japanese Patent Application Laid-Open No. 2003-47406 Summary of the Invention

[0010] Technical problem to be solved by the invention

[0011] Conventional methods for producing coffee extracts using enzyme treatments have not been able to sufficiently reduce turbidity.

[0012] Therefore, an object of the present invention is to provide a technology for producing a coffee extract capable of further reducing the turbidity of the coffee extract.

[0013] Means for solving technical problems

[0014] The present inventors have discovered that glucoamylase has an extremely excellent effect on reducing the turbidity of coffee extracts. Based on this, turbidity can be effectively reduced by using a relatively small amount of glucoamylase, and that turbidity can be significantly reduced by combining glucoamylase with galactomannanase at a predetermined ratio or higher. Specifically, the present invention provides the following aspects.

[0015] Item 1. A method for producing a coffee extract, comprising contacting the coffee extract with a glucoamylase having a glucoamylase activity of 32 U or less per 1 g of coffee beans.

[0016] Item 2. The production method according to Item 1, wherein in the step, the coffee extract is extracted from a slurry containing ground coffee, water, and the glucoamylase.

[0017] Item 3. The production method according to Item 1 or 2, wherein the glucoamylase having a glucoamylase activity of 0.5 U or more per 1 g of the coffee beans is used.

[0018] Item 4. A method for producing a coffee extract, comprising contacting a coffee extract with glucoamylase and a galactomannanase, wherein the glucoamylase having a glucoamylase activity of 0.24 U or more per 1 U of the galactomannanase activity is used.

[0019] Item 5. The production method according to Item 4, wherein in the step, the coffee extract is extracted from a slurry containing ground coffee, water, the glucoamylase, and the galactomannanase.

[0020] Item 6. The production method according to Item 4 or 5, wherein the glucoamylase having a glucoamylase activity of 2 U or less per 1 U of the galactomannanase activity is used.

[0021] Item 7. The production method according to any one of Items 1 to 6, wherein the glucoamylase having a glucoamylase activity of 20 U or less per 1 g of coffee beans is used.

[0022] Item 8. The production method according to any one of Items 1 to 7, wherein the glucoamylase is derived from Rhizopus oryzae.

[0023] Item 9. An enzyme preparation, characterized in that

[0024] The enzyme preparation comprises glucoamylase,

[0025] The enzyme preparation is used for turbidity reduction of coffee extract.

[0026] Item 10. The enzyme preparation according to Item 9, wherein the enzyme preparation is used in an amount such that the glucoamylase activity per 1 g of coffee beans is 32 U or less.

[0027] Item 11. The enzyme preparation according to Item 9 or 10, further comprising a galactomannanase; and wherein the content of the glucoamylase is 0.24 U of glucoamylase activity per 1 U of the galactomannanase activity.

[0028] Effects of the Invention

[0029] According to the present invention, a technology for producing a coffee extract capable of further reducing the turbidity of the coffee extract is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a graph comparing the turbidity (NTU) of coffee extracts obtained in Reference Example 2-1 (when only glucoamylase was used), Examples 2-1 and 2-2 (when glucoamylase and galactomannanase were used in combination at a specified ratio), Comparative Example 2-2 (when glucoamylase and galactomannanase were used in combination at a ratio deviating from the specified ratio), and Comparative Example 2-3 (when only galactomannanase was used).

[0031] Figure 2 This is a graph comparing the filtration rates (m / hour) of coffee extracts obtained in Comparative Example 2-4 (when no enzyme was used), Reference Example 2-2 (when only glucoamylase was used), Example 2-3 (when glucoamylase and galactomannanase were used in combination at a predetermined ratio), and Comparative Example 2-5 (when only galactomannanase was used). DETAILED DESCRIPTION

[0032] 1. Method for producing coffee extract

[0033] 1-1. Enzyme treatment process

[0034] A first embodiment of the method for producing a coffee extract of the present invention is characterized by comprising a step of contacting the coffee extract with a glucoamylase having a glucoamylase activity of 32 U or less per 1 g of coffee beans (enzyme treatment step) to obtain the coffee extract.

[0035] Glucoamylase has an extremely excellent turbidity-reducing effect on coffee extracts, and thus, even when used in a small amount relative to a prescribed amount of coffee beans, the turbidity-reducing effect of the coffee extract can be effectively achieved. Furthermore, in addition to its turbidity-reducing effect on coffee extracts, glucoamylase also has an extremely excellent filtration-speed-enhancing effect on coffee extracts, and thus, even when used in a small amount relative to a prescribed amount of coffee beans, the filtration-speed-enhancing effect of the coffee extract can be effectively achieved. Therefore, from the perspective of balancing the turbidity-reducing effect on the coffee extract (or the turbidity-reducing effect and the filtration-speed-enhancing effect) with the use of glucoamylase, preferred examples of the amount of glucoamylase used in the first embodiment of the present invention include a glucoamylase activity of preferably 16 U or less, more preferably 14 U or less, even more preferably 12 U or less, even more preferably 10 U or less, even more preferably 8 U or less, and particularly preferably 7 U or less.

[0036] In the first embodiment of the method for producing a coffee extract of the present invention, the lower limit of the range of the amount of glucoamylase used per 1g of coffee beans is not particularly limited and can be appropriately determined based on the degree to which the turbidity in the coffee extract should be reduced (or the degree to which the turbidity should be reduced and the degree to which the filtration speed should be improved). However, a glucoamylase activity of 1U or greater per 1g of coffee beans is preferred. From the perspective of further enhancing the turbidity-reducing effect (or the turbidity-reducing effect and the filtration speed-enhancing effect) of the coffee extract, the amount of glucoamylase used per 1g of coffee beans is preferably 0.5U or greater, more preferably 0.8U or greater, even more preferably 1U or greater, even more preferably 1.3U or greater, and particularly preferably 1.5U or greater.

[0037] In the present invention, the activity value of glucoamylase is defined as 1 U, which is the amount of enzyme that increases the reducing power of 1 mg of glucose in 1 minute.

[0038] A second embodiment of the method for producing a coffee extract of the present invention is characterized in that it includes a step of contacting the coffee extract with glucoamylase and galactomannanase (enzyme treatment step), and the coffee extract is obtained using the glucoamylase having a glucoamylase activity of 0.24 U or more per 1 U of the galactomannanase activity.

[0039] Combining glucoamylase with a galactomannanase can increase the soluble solids content in a coffee extract. On the other hand, galactomannanase not only lacks a turbidity-reducing effect on a coffee extract, but also, when combined with a glucoamylase, partially eliminates the turbidity-reducing effect of the glucoamylase on the coffee extract. Furthermore, galactomannanase not only lacks a filtration rate-enhancing effect on a coffee extract, but, when combined with a glucoamylase, partially eliminates the filtration rate-enhancing effect of the glucoamylase on the coffee extract. However, because glucoamylase has an extremely excellent turbidity-reducing effect (or both turbidity-reducing and filtration rate-enhancing effects) on a coffee extract, in a second embodiment of the method for producing a coffee extract of the present invention, by using a glucoamylase with a glucoamylase activity of 0.24 U or more per 1 U of galactomannanase activity, the loss of the turbidity-reducing effect (or both turbidity-reducing and filtration rate-enhancing effects) due to the combination with the glucoamylase can be suppressed, allowing the turbidity-reducing effect (or both turbidity-reducing and filtration rate-enhancing effects) of the coffee extract to be effectively achieved.

[0040] In a second embodiment of the method for producing a coffee extract of the present invention, from the viewpoint of further improving the turbidity-reducing effect (or the turbidity-reducing effect and the filtration speed-improving effect) of the coffee extract, the amount of glucoamylase used per 1 U of galactomannanase activity is preferably 0.4 U or more, more preferably 0.5 U or more, and even more preferably 0.6 U or more.

[0041] In a second embodiment of the method for producing a coffee extract of the present invention, the upper limit of the range of the amount of glucoamylase used per 1U of galactomannanase activity is not particularly limited, but an example thereof is 2U or less of glucoamylase activity. Glucoamylase has an extremely excellent turbidity-reducing effect (or turbidity-reducing effect and filtration speed-enhancing effect) on the coffee extract, so even if a large amount of glucoamylase is used, the turbidity-reducing effect (or turbidity-reducing effect and filtration speed-enhancing effect) of the coffee extract can be effectively achieved. From the perspective of saving glucoamylase, the upper limit of the range of the amount of glucoamylase used per 1U of galactomannanase activity is preferably 1.5U or less of glucoamylase activity, more preferably 1.3U or less, even more preferably 1U or less, even more preferably 0.8U or less, and particularly preferably 0.7U or less.

[0042] In the present invention, the activity value of galactomannanase is defined as 1 U, which is the amount of enzyme that increases the reducing power of 1 μmol of mannose in 1 minute.

[0043] In the second embodiment of the method for producing a coffee extract of the present invention, the amount of coffee beans used relative to the glucoamylase is not particularly limited, and the amount described in the first embodiment can be used.

[0044] That is, glucoamylase is extremely excellent in the turbidity-reducing effect of the coffee extract, and even if the amount used relative to the prescribed amount of coffee beans is small, the turbidity-reducing effect of the coffee extract (or the turbidity-reducing effect and the filtration speed-improving effect) can be effectively obtained. Therefore, from the perspective of balancing the turbidity-reducing effect (or the turbidity-reducing effect and the filtration speed-improving effect) of the coffee extract and the conservation of glucoamylase, preferred examples of the amount of glucoamylase used in the second embodiment of the present invention include, for example, a glucoamylase activity of 32 U or less, preferably 16 U or less, more preferably 14 U or less, even more preferably 12 U or less, even more preferably 10 U or less, even more preferably 8 U or less, and particularly preferably 7 U or less.

[0045] In the second embodiment of the method for producing a coffee extract of the present invention, the lower limit of the range of the amount of glucoamylase used per 1 g of coffee beans is not particularly limited and can be appropriately determined depending on the degree to which the turbidity in the coffee extract should be reduced (or the degree to which the turbidity should be reduced and the degree to which the filtration speed should be improved). For example, a glucoamylase activity of 1 U or more per 1 g of coffee beans can be used. From the viewpoint of further improving the turbidity-reducing effect (or the turbidity-reducing effect and the filtration speed-improving effect) of the coffee extract, it is preferably 1.5 U or more, more preferably 2 U or more, even more preferably 4 U or more, even more preferably 4.5 U or more, even more preferably 5 U or more, and particularly preferably 6 U or more.

[0046] The coffee beans used in the present invention are not particularly limited in the first embodiment and the second embodiment, as long as they are roasted coffee beans suitable for coffee extraction. Therefore, as the origin of coffee beans, there is no particular limitation, and examples include Robusta species (Indonesia, Vietnam, Uganda), Arabica species (Brazil, Kilimanjaro, Peru, Colombia, Guatemala), etc., and these coffee beans can be used alone or in combination of two or more. In addition, there is no particular limitation on the roasting grade of coffee beans, and examples include extremely light roasting (Light roast), cinnamon roasting (Cinnamon roast), micro-medium roasting (Medium roast), medium roasting (High roast), medium-deep roasting (City roast), deep roasting (Full city roast), French roasting (French roast), Italian roasting (Italian roast), etc., and one of these roasting grades can be used alone, or two or more beans with different roasting grades can be used in combination.

[0047] In the present invention, in the step of contacting the coffee extract with the enzyme (glucoamylase, or glucoamylase and galactomannanase) (enzyme treatment step), the timing of contacting the coffee extract with the enzyme is not particularly limited in both the first and second embodiments. For example, it is also possible to extract coffee grounds and prepare a coffee extract (coffee extract liquid) in advance, and then mix the coffee extract and the enzyme. In addition, it is also possible to extract the coffee extract from a slurry containing coffee grounds, water and enzymes, and in fact, to simultaneously prepare the coffee extract and contact the coffee extract and the enzyme. In the present invention, it is preferred to simultaneously prepare the coffee extract and contact the coffee extract and the enzyme. It should be noted that the water contained in the above-mentioned slurry refers to water with no temperature limit, and also includes non-heated water and heated water (hot water, etc.). In addition, the slurry may contain a coffee extract liquid. In this case, the slurry can contain coffee grounds and a coffee extract liquid (a liquid containing a water extract of coffee in water) and an enzyme.

[0048] In the present invention, the pH and temperature conditions for contacting the coffee extract with the enzyme (glucoamylase, or glucoamylase and galactomannanase) can be appropriately determined based on the optimal pH and temperature of the enzymes used. For example, the pH condition may be 3 to 8, preferably 4 to 7, more preferably 5 to 6, and even more preferably 5 to 5.5. The temperature condition may be 10 to 50°C, preferably 20 to 40°C.

[0049] The temperature and pressure conditions for coffee extraction are not particularly limited. The temperature conditions may be either water extraction (non-heated extraction) or heated extraction, with water extraction being preferred. Furthermore, when preparing the coffee extract and contacting the coffee extract with an enzyme are performed simultaneously, the temperature conditions may be determined based on the optimal temperature of the enzyme. In this case, specific examples include 10-50°C, preferably 20-40°C. The pressure conditions may be either pressurized extraction or non-pressurized extraction.

[0050] In the present invention, the time for contacting the coffee extract with the enzyme (glucoamylase, or glucoamylase and galactomannanase) is not particularly limited, and may be, for example, 30 minutes to 5 hours, preferably 1 to 4 hours, and more preferably 1.5 to 3 hours.

[0051] The glucoamylase used in the present invention is an enzyme (EC3.2.1.3) with exo-1,4-α-glucosidase activity. In any one of the first embodiment and the second embodiment, as a specific example, glucoamylase preferably derived from Aspergillus (Aspergillus) such as Rhizopus, Eudomyces, Penicillium, Nurospora, Trichoderma, and Mucor can be enumerated. In addition, as the glucoamylase derived from Rhizopus, it is not particularly limited, and Rhizopus oryzae, Rhizopus delemer, Rhizopus niveus, etc. can be enumerated. These glucoamylases can be used alone or in combination.

[0052] Among these glucoamylases, from the viewpoint of further improving the turbidity-reducing effect (or the turbidity-reducing effect and the filtration speed-improving effect) of the coffee extract, glucoamylases derived from the genus Rhizopus are more preferred, and glucoamylases derived from Rhizopus oryzae are even more preferred.

[0053] The titer of the glucoamylase is, for example, 500 U / g or more, preferably 1000 U / g or more, and more preferably 1500 U / g or more. The upper limit of the titer of the glucoamylase is not particularly limited, but is, for example, 10000 U / g or less, preferably 5000 U / g or less, and more preferably 2000 U / g or less.

[0054] The galactomannanase used in the second embodiment of the method for producing a coffee extract of the present invention is an enzyme having endo-1,4-β-mannanase activity (EC 3.2.1.78). Specific examples thereof are not particularly limited, but include galactomannanases derived from the genus Aspergillus. Aspergillus-derived galactomannanases are preferably derived from Aspergillus niger.

[0055] The titer of the galactomannanase is, for example, 1000 U / g or more, preferably 5000 U / g or more, and more preferably 8000 U / g or more. The upper limit of the titer of the galactomannanase is not particularly limited, but is, for example, 50000 U / g or less, preferably 30000 U / g or less, and more preferably 15000 U / g or less.

[0056] 1-2. Other processes

[0057] In the present invention, the coffee extract with reduced turbidity (or reduced turbidity and improved filtration rate) obtained through the enzyme treatment step described above can be appropriately subjected to an enzyme inactivation step, a coffee bean separation step using centrifugation, static separation, and / or filtration, and / or a sterilization step. The order of the enzyme inactivation step, coffee bean separation step, and sterilization step is arbitrary.

[0058] 1-3. Use of coffee extract

[0059] The coffee extract with reduced turbidity (or reduced turbidity and increased filtration speed) obtained by the present invention can be directly used in the manufacture of coffee food and beverages, or can be prepared into a concentrated solution or dry extract by appropriately removing water, and then diluted with water as needed for use in the manufacture of coffee food and beverages.

[0060] Among coffee foods and beverages, coffee beverages include, for example, sugar-free black coffee; sweetened black coffee to which sucrose, liquid sugar, sweeteners, etc. are added; and cafe au lait-type coffee beverages to which milk, skimmed milk powder, fresh cream, etc. are added to sugar-free or sweetened coffee beverages.

[0061] Among coffee foods and beverages, coffee foods include, for example, coffee-flavored frozen desserts / refrigerated desserts such as jelly, pudding, ice cream, and popsicles; and coffee-flavored confectionery / baked goods such as cakes, candies, cookies, and bread.

[0062] When producing coffee drinks and beverages, any material that can be used in coffee drinks and beverages can be added to the coffee extract with reduced turbidity (or reduced turbidity and increased filtration rate). Examples of such materials include milk components, sugars, sweeteners, salt, wheat flour, eggs, and the like. Furthermore, when producing coffee drinks and beverages, any component that can be used in coffee drinks and beverages can be added to the coffee extract with reduced turbidity (or reduced turbidity and increased filtration rate). Examples of such components include antioxidants, pH adjusters, emulsifiers, flavorings, stabilizers, antioxidants, and preservatives.

[0063] 2. Enzyme preparation for turbidity of coffee extract

[0064] As shown above, in either the first or second embodiment of the production method of the present invention, glucoamylase can significantly reduce the turbidity of a coffee extract. Therefore, the present invention also provides an enzyme preparation further comprising a glucoamylase, which is used to reduce the turbidity of a coffee extract. Furthermore, as shown above, glucoamylase can significantly increase the filtration rate of a coffee extract. Therefore, the enzyme preparation of the present invention can also be used to increase the filtration rate.

[0065] As shown in the first and second embodiments of the production methods of the present invention, the enzyme preparation of the present invention can be used in an amount of 32 U or less per 1 g of coffee beans. Furthermore, as shown in the second embodiment of the production method of the present invention, the enzyme preparation of the present invention can further comprise a galactomannanase, wherein the content of the glucoamylase is 0.24 U per 1 U of the galactomannanase activity.

[0066] Reducing the turbidity of a coffee extract means obtaining a coffee extract having a lower turbidity than that of a coffee extract obtained without enzyme treatment. The degree of reduction in turbidity of the coffee extract, expressed as a relative turbidity with the turbidity of the coffee extract obtained without enzyme treatment set to 1, is preferably 0.4 or less, and more preferably 0.3 or less. Turbidity can be determined, for example, as the turbidity (NTU) when the coffee extract is diluted with water to achieve a Brix of 2.

[0067] Furthermore, increasing the filtration rate of the coffee extract means obtaining a coffee extract having a higher filtration rate than the filtration rate of the coffee extract obtained without enzyme treatment. It should be noted that the degree of improvement in the filtration rate of the coffee extract, as a relative filtration rate when the filtration rate of the coffee extract obtained without enzyme treatment is set to 1, is preferably 5.5 or more, more preferably 6 or more, and even more preferably 6.5 or more. It should be noted that the filtration rate can be calculated as the amount of filtrate (m3 )×1 / filtration area (m 2 )×1 / hour (hr) to obtain the value.

[0068] In the enzyme preparation of the present invention, details of various enzymes and methods of use are as described in the above-mentioned "1. Method for producing coffee extract".

[0069] In addition to glucoamylase and galactomannanase, the enzyme preparation of the present invention may further comprise other food-scientifically acceptable ingredients, such as excipients, disintegrants, preservatives, stabilizers, vitamins, minerals, sweeteners, and flavorings.

[0070] Example

[0071] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not to be construed as being limited to the following Examples.

[0072] (1) Activity value determination method

[0073] The method for measuring the titer (activity value) of glucoamylase and galactomannanase is as follows.

[0074] Glucoamylase (GA) activity

[0075] The measurement was performed by the following method according to the fourth method of the glucoamylase activity test method of the ninth edition of the Official Standards of Food Additives (the Japanese original of "Food Additives Official Standards" is "Food Additives Official Standards").

[0076] 0.50g of enzyme sample was measured and diluted with water to an appropriate concentration as the sample solution. Potato starch was dried at 105°C for 2 hours, and 1.0g of the dried product was weighed. 20mL of water was added, and 5mL of sodium hydroxide solution (2mol / L) was slowly added while stirring to form a paste. The starch paste was heated in a water bath while stirring for 3 minutes, and then 25mL of water was added. After cooling, hydrochloric acid solution (2mol / L) and hydrochloric acid solution (0.1mol / L) were added to neutralize the mixture. 10mL of 1mol / L acetic acid and sodium acetate buffer (pH 4.5) was added, and further water was added to prepare a 100mL solution as the substrate solution.

[0077] Measure 10 mL of substrate solution and heat it at 37°C for 10 minutes. Add 1 mL of sample solution and immediately shake to mix. After heating at 37°C for 10 minutes, add 4 mL of Fehling's solution and gently shake to mix. Heat in a water bath for 15 minutes, cool to below 25°C, and add 2 mL of potassium iodide solution and 2 mL of sulfuric acid (dilute 1 part sulfuric acid by volume with water to make 6 parts sulfuric acid by volume) to prepare a test solution. Separately, replace the substrate solution with 10 mL of water and follow the same procedure as for the test solution to prepare a comparative solution. The test and comparative solutions are titrated for free iodine using 0.05 mol / L sodium thiosulfate solution. The endpoint is determined by adding 1 to 2 drops of soluble starch solution near the endpoint, resulting in the disappearance of the resulting blue color. Under these conditions, 1 unit (1 U) is defined as the amount of enzyme that increases the reducing power of 1 mg of glucose in 1 minute. The glucoamylase activity is calculated using the following formula.

[0078] [Mathematical formula 1]

[0079] Glucoamylase activity (U / g) = amount of glucose (mg) × 1 / 10 × 1 / M

[0080] Amount of glucose (mg) = (b - a) × 1.6 × f

[0081] a: titration value of test solution (mL)

[0082] b: titration value of comparison solution (mL)

[0083] 1.6: 1 mL of 0.05 mol / L sodium thiosulfate solution is equivalent to 1.6 mg of glucose

[0084] 1 / 10: Unit conversion factor for reaction time (minutes)

[0085] M: The amount of enzyme sample in 1 mL of sample solution (g or mL)

[0086] f: Factor of 0.05 mol / L sodium thiosulfate solution

[0087] <Galactomannanase (GM) activity>

[0088] The determination was carried out by the following method based on the fifth method of the hemicellulase activity test method in the ninth edition of the official standard for food additives.

[0089] Measure 0.50g enzyme sample, add water and dilute to the sample of appropriate concentration as sample liquid.Measure 0.6g locust bean gum (Locust Bean Gum) (enzyme is used), after adding 100mL water and stirring, after 600W heating in microwave oven for 2 minutes, stir 1 minute.After heating 2 minutes with 600W heating in microwave oven again, stir 1 minute, cool in flowing water.After cooling, add 5mol / L hydrochloric acid test solution 6mL while stirring at room temperature, after stirring 15 minutes, add 1mol / L acetic acid sodium acetate buffer (pH5.0) 6mL, use 0.5mol / L sodium hydroxide test solution that pH is adjusted to 5.0.Use water to be settled to 300mL, with 8000rpm centrifugation 15 minutes, using supernatant as substrate solution.

[0090] Weigh 4 mL of substrate solution into a 50 mL Nessler tube, heat at 40°C for 10 minutes, add 1 mL of sample solution, shake and mix, and heat at 40°C for 10 minutes. Add 2 mL of Somogyi test solution to this solution and mix. Gently stopper the Nessler tube and heat in a water bath for 30 minutes. After cooling, add 2 mL of Nelson's test solution to this solution and mix. After standing for 20 minutes, add water to 30 mL and centrifuge at 3000 rpm for 15 minutes. The supernatant is used as the test solution. Separately, measure 1 mL of sample solution into a 50 mL Nessler tube, add 2 mL of Somogyi test solution (I) and shake and mix. Then, add 4 mL of substrate solution and mix. Gently stopper the Nessler tube and heat in a water bath for 30 minutes. The same procedures as for the test solution are repeated to prepare this solution as the comparison solution. The absorbance of the test and comparison solutions at a wavelength of 750 nm is measured. Under these conditions, the amount of enzyme that increases the reducing power of 1 μmol of mannose in 1 minute is defined as 1 unit (1 U), and the galactomannanase activity is calculated from the following formula.

[0091] [Mathematical formula 2]

[0092] Galactomannanase activity (U / g) = (A1-A0) × 0.163 × 1 / 10 × 1 / 0.18 × n

[0093] A1: Absorbance of the test solution

[0094] A0: Absorbance of comparison solution

[0095] 0.163: coefficient

[0096] 1 / 10: Conversion factor per minute

[0097] 1 / 0.18: mannose 1 μmol = 0.180 mg

[0098] n: dilution factor per 1g enzyme sample

[0099] (2) Experimental methods and results

[0100] (2-1) Turbidity and soluble solids content of coffee extracts based on the use of glucoamylase

[0101] Commercially available coffee (100% Arabica from Colombia, medium roast) was ground into 150 g of coffee powder, 150 g of water, and the enzymes shown in Tables 1 and 2 (glucoamylase (GA) derived from Rhizopus oryzae manufactured by Amano Enzyme Co., Ltd., trade name saccharifying enzyme AF6; hemicellulase manufactured by Amano Enzyme Co., Ltd., trade name hemicellulase "AMANO" 90; pectinase manufactured by Amano Enzyme Co., Ltd., trade name pectinase PL "AMANO"; pectinase manufactured by Amano Enzyme Co., Ltd., trade name pectinase G "AMANO"; galactomannanase (GM) derived from Aspergillus niger manufactured by Amano Enzyme Co., Ltd., trade name mannanase BGM "AMANO" 10; β-glucanase manufactured by BioCat Co., Ltd., trade name Beta-Glucanase 3000 BGU / g (the same applies hereinafter) was thoroughly mixed in the indicated amounts to prepare a coffee bean slurry, which was then placed in a French press coffee machine. 600 g of water was further added, and the mixture was allowed to stand at room temperature (25°C) and pH 5.2 for 2 hours. A coffee extract (coffee extract liquid) was recovered by pressing with a French press.

[0102] The turbidity was measured using a turbidimeter (manufactured by HANNA Corporation, model number: HI93703) by diluting the coffee extract (coffee extract liquid) with water to give a Brix of 2. The results are shown in Tables 1 and 2.

[0103] The soluble solids yield was calculated using the following formula by measuring the Brix and TDS (total dissolved solids) of the coffee extract (coffee extract liquid) using a PAL-COFFEE (BX / TDS) analyzer manufactured by ATAGO Co., Ltd. The results are shown in Tables 1 and 2.

[0104] [Mathematical formula 3]

[0105] Soluble solid content yield (%) = extract (mL) × TDS (%) / coffee beans (g) × 100

[0106] [Table 1]

[0107]

[0108] [Table 2]

[0109]

[0110] As shown in Table 1, a significant turbidity-reducing effect was observed when glucoamylase (saccharifying enzyme AF6) was used (Example 1-1) according to the first embodiment of the present invention, compared to the cases where various enzymes effective in reducing the turbidity of the coffee extract were used (Comparative Examples 1-2 to 1-6). It should be noted that for the case where glucoamylase (saccharifying enzyme AF6) was used at 8 U per 1 g of coffee beans, reference can be made to Reference Examples 2-1 and 2-2 described below (also corresponding to the examples of the first embodiment of the present invention). Furthermore, for the case where glucoamylase (saccharifying enzyme AF6) was used in combination with galactomannanase (mannanase BGM10), reference can be made to Examples 2-1 to 2-3 described below (also corresponding to the examples of the first embodiment of the present invention).

[0111] In addition, as can be seen from Table 2, when glucoamylase (saccharifying enzyme AF6) is used based on the first embodiment of the present invention, the turbidity reducing effect is improved depending on the usage amount (Examples 1-1 to 1-3). On the other hand, when other enzymes are used, the turbidity reducing effect is almost unchanged regardless of the usage amount (Comparative Examples 1-5 to 1-10).

[0112] (2-2) Turbidity and soluble solids content of coffee extracts using glucoamylase and galactomannanase

[0113] <Method>

[0114] Coffee bean slurry was prepared by thoroughly mixing 200 g of commercially available coffee (100% Arabica, Colombian, medium roast), 200 g of water, and the enzymes listed in Table 3 (in the indicated amounts). The coffee bean slurry was placed in a reactor fitted with filter paper (Whatman, No. 1 (pore diameter = 11 μm)) at the bottom. 600 g of water was added, and the mixture was allowed to stand at room temperature (25°C) and pH 5.2 for 2 hours. Coffee extract (coffee extract liquid) was recovered from the bottom of the reactor by natural descent and compressed air extrusion.

[0115] The turbidity and soluble solid content yield of the coffee extract (coffee extract) were measured in the same manner as in (3-1). The results are shown in Table 3 below. In addition, a graph comparing the turbidity (NTU) of Reference Example 2-1, Examples 2-1 to 2-2, and Comparative Examples 2-2 to 2-3 is shown in Figure 1 .

[0116] [Table 3]

[0117]

[0118] As can be seen from Table 3, compared with the case where glucoamylase (saccharifying enzyme AF6) was used alone (Reference Example 2-1) and the case where galactomannanase (mannanase BGM10) was used alone (Comparative Example 2-3), when these enzymes were used in combination (Example 2-1, Example 2-2, Comparative Example 2-2), the yield of the soluble solid component was confirmed to be significantly improved.

[0119] In addition, in the above (3-1), it was shown that glucoamylase (saccharifying enzyme AF6) had an extremely excellent effect of reducing the turbidity of the coffee extract, as shown in Tables 3 and Figure 1 Reference Example 2-1 also showed extremely excellent effects.

[0120] However, in the combination of glucoamylase (saccharifying enzyme AF6) and galactomannanase (mannanase BGM10), the yield of soluble solid components was greatly improved. Figure 1 As shown in FIG, when the amount of glucoamylase GA relative to galactomannanase GM is small (Comparative Example 2-2), the turbidity-reducing effect of glucoamylase GA on the coffee extract is significantly impaired. Figure 1 As shown, when glucoamylase GA is used in an amount greater than or equal to the prescribed amount relative to galactomannanase GM (Examples 2-1 and 2-2, particularly Example 2-1), the loss of the turbidity-reducing effect of the coffee extract due to the addition of galactomannanase GM can be suppressed. Therefore, by using glucoamylase GA in an amount greater than or equal to the prescribed amount relative to galactomannanase GM, it is possible to achieve an excellent turbidity-reducing effect while increasing the yield of the soluble solids content of the coffee extract.

[0121] (2-3) Filtration speed

[0122] 200 g of commercially available ground coffee, 200 g of water, and the enzymes listed in Table 4 (indicated amounts) were thoroughly mixed to prepare a coffee bean slurry. The coffee bean slurry was placed in a reactor fitted with filter paper (Whatman, No. 1 (pore diameter = 11 μm)) at the bottom. 800 g of water was added, and the mixture was allowed to stand at room temperature for 2 hours. Coffee extract (coffee extract liquid) was recovered from the bottom of the reactor by natural descent and compressed air extrusion.

[0123] The turbidity of the coffee extract (coffee extract liquid) was measured in the same manner as in (3-1) above. Separately, 200 mL of the coffee extract (coffee extract liquid) was filtered (-0.5 bar) using filter paper (Whatman, diameter 90 mm, No. 3 (pore diameter = 6 μm)) and the filtration rate (m / h) and the amount of filtrate (m 3 )×1 / filtration area (m 2)×1 / hour (hr)). The results are shown in Table 4. In addition, the results of the filtration rate measurements are also shown in Table 4. Figure 2 .

[0124] [Table 4]

[0125]

[0126] It can be seen from Table 4 that turbidity is correlated with filtration speed. Figure 2 It can be seen that glucoamylase (saccharifying enzyme AF6), which has an extremely excellent turbidity-reducing effect on coffee extract, also exhibits an extremely high filtration speed-improving effect (Reference Example 2-2). Galactomannanase (mannanase BGM10), which has a poor turbidity-reducing effect on coffee extract, also has a poor filtration speed-improving effect (Comparative Example 2-5). Meanwhile, in the combination of glucoamylase (saccharifying enzyme AF6), which significantly increases the yield of soluble solids, and galactomannanase (mannanase BGM10), when a predetermined amount of glucoamylase (GA) relative to the galactomannanase (GM) is used (Example 2-3), an excellent filtration speed-improving effect is achieved. Therefore, by using a predetermined amount of glucoamylase (GA) relative to the galactomannanase (GM), the yield of soluble solids in coffee extract can be increased while also achieving an excellent turbidity-reducing effect and an excellent filtration speed-improving effect.

[0127] (2-4) Changes in turbidity of coffee extracts using glucoamylase and galactomannanase

[0128] <Method>

[0129] 150 g of commercially available coffee (100% Arabica from Colombia, slightly roasted) ground powder, 150 g of water, saccharifying enzyme AF6 (6.4 U / 1 g of coffee beans) and mannanase BGM10 (10 U / 1 g of coffee beans) were thoroughly mixed to form a coffee bean slurry, which was then put into a French press coffee machine. 450 g of water was further added and the mixture was allowed to stand at room temperature (25°C) for 2 hours. The coffee extract (coffee extract) was recovered by squeezing using a French press. The recovered extract was then concentrated to about 40 mL under reduced pressure (60°C, 30 rpm, -1 bar) to obtain a coffee concentrate. Next, 3% of the liquid volume of diatomaceous earth (Celite Hyflo) was added to the concentrate, and suction filtration (-1 bar) was performed using filter paper coated with diatomaceous earth (Celite Hyflo). The resultant concentrate was further heat-treated (90°C, 5 minutes) to obtain a clarified coffee concentrate. The obtained concentrate was stored at 4°C. To determine the change in turbidity over time during storage, the samples were diluted with water to a Brix of 2 and measured using a turbidimeter (manufactured by HANNA Corporation, Model: HI93703). The turbidity (NTU) immediately after preparation in Comparative Example 2-6 was set to 1, and relative turbidity was derived at each time point. The results are shown in Table 5 below.

[0130] [Table 5]

[0131]

[0132] As can be seen from Table 5, by using a combination of glucoamylase (saccharifying enzyme AF6) and galactomannanase (mannanase BGM10) (Example 2-4), not only the turbidity of the coffee extract immediately after preparation can be significantly suppressed, but also the increase in turbidity during storage of the coffee extract can be significantly suppressed, compared to the case where no enzyme is used (Comparative Example 2-6). Therefore, it can be confirmed that further significant stability (turbidity reduction effect) is achieved after storage of the coffee extract.

Claims

1. A method for producing a coffee extract, comprising treating the coffee extract with a glucoamylase having a glucoamylase activity of 32 U or less per 1 g of coffee beans, No galactomannanase was used in the process.

2. The manufacturing method according to claim 1, wherein In the process, a coffee extract is extracted from a slurry comprising coffee grounds, water and the glucoamylase.

3. The manufacturing method according to claim 1 or 2, wherein: The glucoamylase having a glucoamylase activity of 0.5 U or more per 1 g of the coffee beans is used.

4. The manufacturing method according to claim 1 or 2, wherein: The glucoamylase is derived from Rhizopus oryzae.

5. A method for producing a coffee extract, comprising the step of contacting the coffee extract with glucoamylase and galactomannanase, wherein: For every 1 U of the galactomannanase activity, the glucoamylase having a glucoamylase activity of 0.24 U or more is used. The glucoamylase used has a glucoamylase activity of 20 U or less per 1 g of coffee beans.

6. The manufacturing method according to claim 5, wherein: In the process, a coffee extract is extracted from a slurry comprising coffee grounds, water, the glucoamylase and the galactomannanase.

7. The manufacturing method according to claim 5 or 6, wherein: The glucoamylase is used at a glucoamylase activity of 2 U or less per 1 U of the galactomannanase activity.

8. The manufacturing method according to claim 5 or 6, wherein: The glucoamylase is derived from Rhizopus oryzae.

9. An enzyme preparation, characterized in that The enzyme preparation comprises glucoamylase and galactomannanase, wherein the content of the glucoamylase is 0.24 U or more of glucoamylase activity per 1 U of the galactomannanase activity. The enzyme preparation is used for reducing the turbidity of coffee extract, The enzyme preparation is used in an amount such that the glucoamylase activity per 1 g of coffee beans is 32 U or less.

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