Alcoholic beverage manufacturing method

Abstract

To provide an alcoholic beverage production method reducing, dissolved oxygen, having freshness, and holding a scent of the alcoholic beverage, especially, a brewing scent which is preferable in brewage such as sake.SOLUTION: A deaerator having a hollow fiber membrane module 16 is used for flowing an alcoholic beverage to a liquid phase part of the hollow fiber membrane module, a gas phase part is held in a negative pressure state, and in the state, a step for flowing a carbon dioxide gas or a carbon dioxide gas and an inactive gas, is executed, in a production method of an alcoholic beverage. A ratio of a dissolved carbon dioxide amount after processing, to a dissolved carbon dioxide amount before processing of the above-mentioned step, is, in a range of 1 / 500 or greater in terms of mass. In addition, it is preferable that the dissolved oxygen amount in the alcoholic beverage acquired through the step, is in a range up to 10 ppm or lower.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing alcoholic beverages. [Background technology]

[0002] It has long been known that the development of undesirable aromas, such as aged aromas and coloring, in alcoholic beverages, particularly brewed alcoholic beverages, is due to the oxidation of alcoholic beverage components. Furthermore, unpasteurized sake, such as unpasteurized sake, contains approximately twice the dissolved oxygen of conventional pasteurized sake and deteriorates in quality more quickly than pasteurized sake. It is known that reducing the dissolved oxygen concentration in alcoholic beverages by reducing the pressure using hollow fiber or film-type membrane degassing devices can inhibit the oxidation of alcoholic beverage components and maintain desirable quality at the time of production for a long period of time (see, for example, Patent Document 1). To achieve this effect, it is considered desirable for the dissolved oxygen concentration in alcoholic beverages to be as low as possible, for example, approximately 0.5 ppm or less. However, no specific comparative data has been presented regarding the correlation between the dissolved oxygen concentration in alcoholic beverages and the shelf life of desirable quality. Therefore, methods have been proposed for producing brewed alcohol that suppress the deterioration of taste and color over long periods of storage by reducing the dissolved oxygen to a specific concentration range by using a membrane degassing device to remove the dissolved oxygen or by using an in-line mixer to mix nitrogen gas in a continuous flow, thereby suppressing the activity of enzymes in the unpasteurized alcohol (see, for example, Patent Document 2). [Prior art documents] [Non-patent literature]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-141840 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-308482 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the dissolved oxygen in alcoholic beverages is reduced by degassing under reduced pressure or by using an in-line mixer, the carbon dioxide (dissolved carbon dioxide) is also reduced at the same time, resulting in a loss of freshness. This also creates the problem of losing the aroma of the alcoholic beverage, particularly the "ginjo aroma" that is considered a desirable aroma in brewed alcoholic beverages such as sake.

[0005] The problem that the present invention aims to solve is to provide a method for producing alcoholic beverages that can reduce dissolved oxygen while maintaining a fresh alcoholic beverage aroma, particularly the "ginjo aroma" that is considered to be a desirable aroma for brewed alcoholic beverages such as sake. [Means for solving the problem]

[0006] As a result of various investigations, the inventors of the present application discovered that the above-mentioned problems could be solved by using a hollow fiber membrane module to reduce the dissolved oxygen in alcoholic beverages under negative pressure while flowing carbon dioxide gas, or carbon dioxide gas and an inert gas, from the upstream side, thereby achieving the present invention.

[0007] That is, the present invention relates to a method for producing alcoholic beverages, which comprises the steps of using a degassing device equipped with a hollow fiber membrane module to pass alcoholic beverages through the liquid phase portion of the hollow fiber membrane module, and, while maintaining a negative pressure on the outlet side of the gas phase portion, passing carbon dioxide gas, or a combination of carbon dioxide gas and an inert gas, through the inlet side of the gas phase portion. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a method for producing alcoholic beverages that can reduce dissolved oxygen while maintaining a fresh alcoholic beverage aroma, particularly the "ginjo aroma" that is considered to be a desirable aroma for brewed alcoholic beverages such as sake. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an outline of an apparatus used in an example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below, but is not limited to these exemplary embodiments. Furthermore, in the alcoholic beverage production method of the present invention, the steps up to producing alcoholic beverages, particularly unblended sake (new sake) by brewing, are well known and will not be described here. The unblended sake obtained through the brewing process preferably includes a step of passing it through a filtration device to remove microorganisms, particulates, and the like remaining in the unblended sake (filtration step). The alcoholic beverage production method of the present invention then includes a step of passing the alcoholic beverage through a degassing device having a gas phase and a liquid phase and equipped with a hollow fiber membrane module capable of exchanging oxygen molecules and carbon dioxide molecules between the gas and liquid, and then passing carbon dioxide gas, or carbon dioxide gas and an inert gas, through the liquid phase while maintaining negative pressure in the gas phase (deoxygenation step). The alcoholic beverage, particularly unblended sake, is then transferred to a storage container and stored.

[0011] The filtration process uses a filtration device and is roughly composed of two steps: filtration with activated carbon and filtration with a filter. First, filtration with activated carbon corrects the aroma, taste, and color of the alcoholic beverage, particularly unblended sake, in subsequent processes, preventing subsequent deterioration. Next, filtration with a filter removes microorganisms and fine particles that have not been adsorbed by the activated carbon. The filter used here depends on the filtration speed, but it is preferable to use one that is fine enough to remove microorganisms that cause contamination without degrading the quality of the sake.

[0012] Next, in the deoxygenation step, the alcoholic beverage, preferably undiluted alcohol, obtained through the filtration step is sent to a degassing device equipped with a hollow fiber membrane module, and allowed to flow through the liquid phase side of the hollow fiber membrane module. At this time, carbon dioxide gas, or carbon dioxide gas and an inert gas, are allowed to flow through the gas phase from the inlet side (upstream side) while the outlet side is maintained at negative pressure (gauge pressure less than 0 atmospheres).

[0013] Known degassing devices equipped with hollow fiber membrane modules can be used in the present invention. Examples of such hollow fiber membrane modules include internal reflux-type hollow fiber membrane modules and external reflux-type hollow fiber membrane modules. Regardless of the type of module, alcoholic beverages flow through the liquid phase, while the gas phase requires at least two inlets and outlets. One of these inlets is connected to a vacuum pump to serve as the outlet (downstream) side, maintaining the gas phase at a negative pressure when the vacuum pump is activated. The other inlet is connected to a carbon dioxide gas cylinder or a carbon dioxide gas cylinder and an inert gas cylinder to serve as the inlet (upstream) side, allowing carbon dioxide gas or carbon dioxide and an inert gas to flow through the gas phase when carbon dioxide gas or carbon dioxide and an inert gas are supplied from the cylinder. In this way, by flowing alcoholic beverages through the liquid phase of the hollow fiber membrane module while maintaining the gas phase at a negative pressure, dissolved oxygen can be removed from the alcoholic beverages and transferred to the gas phase through the membrane, while retaining dissolved carbon dioxide. Of these, the external reflux type hollow fiber membrane module has superior treatment efficiency to the internal reflux type hollow fiber membrane module and is capable of suppressing the liquid flow pressure loss to an extremely low level, and is therefore most preferable when treating a large amount of alcoholic beverages.

[0014] The hollow fiber membrane used in the hollow fiber membrane module used in the present invention is not particularly limited. For example, as long as the membrane structure is a laminate of at least a skin layer (dense layer) and a layer having pores (porous layer), any hollow fiber membrane that is normally used as a degassing module or an air intake module can be used without limitation, and the following are also preferably used:

[0015] The hollow fiber membrane used in the present invention is preferably made of a highly hydrophobic material, such as a polyolefin resin such as poly(4-methylpentene-1). The membrane structure is not particularly limited as long as it comprises at least a skin layer (dense layer) and a layer with pores (porous layer). Preferably, the membrane is a heterogeneous membrane comprising a skin layer (dense layer) and a support layer with pores (porous layer). More preferably, the membrane is a heterogeneous membrane comprising an outer skin layer (dense layer) and an inner support layer with pores (porous layer). The pore size is not particularly limited, but may be preferably greater than 0 nm, more preferably at least 0.1 nm, and preferably not greater than 100 nm, more preferably not greater than 50 nm.

[0016] In this way, when a heterogeneous membrane in which a skin layer and a support layer having pores are laminated is used, it is preferable because the resin odor can be reduced by contacting the skin layer with the liquid.

[0017] The hollow fiber membrane used in the hollow fiber membrane module of the present invention preferably has an oxygen permeation rate of 0.1 × 10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg] or more, preferably 0.5×10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg] or more, more preferably 0.9×10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg] or more, and preferably 5000×10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg] or less, preferably 500×10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg] or less, more preferably 100×10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg].

[0018] The hollow fiber membrane used in the hollow fiber membrane module of the present invention preferably has a carbon dioxide permeation rate of 0.1 × 10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg] or more, preferably 0.5×10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg] or more, more preferably 0.9×10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg] or more, and preferably 5000×10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg] or less, preferably 500×10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg] or less, more preferably 100×10 -5 [cm 3 (STP) / cm 2 ·sec·cmHg]. By selecting a value in the above range, it is possible to improve the air supply performance of the module while suppressing leakage of the beverage, which is preferable.

[0019] Furthermore, the hollow fiber membrane used in the hollow fiber membrane module of the present invention preferably has a carbon dioxide / oxygen separation coefficient α = (QCO2: carbon dioxide permeation rate) / (QO2: oxygen permeation rate) = in the range of 1 to 10, more preferably in the range of 1 to 4.5, and particularly preferably in the range of 3.0 to 4.2. Within this range, the membrane is preferably substantially impermeable to alcoholic beverages and is easy to degas to a predetermined dissolved oxygen level or to fill to a predetermined dissolved carbon dioxide level.

[0020] Generally, the degassing performance and carbon dioxide filling performance of the module improve as the oxygen permeation rate and carbon dioxide (carbon dioxide) permeation rate of the hollow fiber membrane increase. However, since this also increases the liquid permeation rate, it is desirable to select a membrane that has an excellent balance between these two properties.

[0021] Moreover, the oxygen transmission rate, carbon dioxide (carbon dioxide gas) transmission rate, and gas separation coefficient α can be easily measured in accordance with ASTM-D1434.

[0022] In particular, hollow fiber heterogeneous membranes made of poly(4-methylpentene-1) resin are preferred because they have excellent gas permeability to oxygen, nitrogen, carbon dioxide, etc., and high water vapor barrier properties. This heterogeneous membrane is described in detail in, for example, JP-B 2-38250, JP-B 2-54377, JP-B 4-15014, JP-B 4-50053, and JP-A 5-6656.

[0023] The module structure and the method of packing the hollow fiber membranes may be configured so as to prevent uneven flow in the degassed water. For example, Japanese Patent Publication No. 2-102714 discloses several suitable module structures.

[0024] The dimensions of the hollow fiber membranes used in the hollow fiber membrane module of the present invention are such that a smaller outer diameter of the hollow fiber membrane allows for a larger membrane area even if the diameter of the wound body is small, and therefore the outer diameter may be preferably 70 μm or more, more preferably 150 μm or more, and preferably 370 μm or less, more preferably 280 μm or less. On the other hand, the inner diameter of the hollow fiber membrane may be preferably 30 μm or more, more preferably 80 μm or more, and preferably 310 μm or less, more preferably 220 μm or less. The membrane area is not particularly limited, but is preferably 0.018 m 2 At least 0.18m, preferably 0.18m 2 More than 1.8m, preferably 1.8m 2 More than 7.0m, especially preferred 2 It may be more than 400m, and preferably 2Less than or equal to 120m, preferably 2 Less than 40m, more preferably 2 Range less than 20m, especially preferred 2 The following ranges may be present:

[0025] The hollow fiber membrane module used in the present invention is characterized by its ability to easily suppress uneven flow of alcoholic beverages flowing through the liquid phase, its excellent pressure resistance, its simple structure, and its ease of manufacture. The hollow fiber blind-like sheet is not particularly limited in shape, and may be a nonwoven fabric, knitted fabric, woven fabric, or the like. However, it is preferably a knitted or woven fabric woven with hollow fiber membranes as the weft or warp and other yarns, such as monofilament or multifilament yarns made of polyester, as the warp or weft. The blind-like sheet-like material can be incorporated into the housing in the form of a stack, wound, or bundled body. It is also possible to adopt other suitable shapes, such as a three-dimensional structure in which hollow fibers are wound around a cylindrical core.

[0026] In the deoxygenation process, the processing flow rate of alcoholic beverages (liquid phase side) per hollow fiber membrane module is preferably 0.1 L / min or more, more preferably 1 L / min or more, from the viewpoint of being able to remove dissolved oxygen in a short time and achieving excellent productivity in alcoholic beverage production, while from the viewpoint of module handleability, it is preferably 100 L / min or less, more preferably 10 L / min or less.

[0027] In the deoxygenation step, the alcoholic beverage flowing through the liquid phase side of the hollow fiber membrane module can be pressurized with a pump or the like, or can be placed in a storage container such as a tank and pressurized with a gas containing carbon dioxide or an inert gas, thereby forcing the alcoholic beverage out of the storage container and introducing it into the hollow fiber membrane module. The pressure at which the alcoholic beverage is pressurized is not particularly limited as long as it is within the range that achieves the above-mentioned treatment flow rate. However, since degassing can be achieved in a short period of time, a pressure of 0.001 MPa or more is preferred as a lower limit, and 0.01 MPa or more is more preferred. On the other hand, from the viewpoint of excellent pressure resistance of the module, a pressure of 1.0 MPa or less is preferred as an upper limit, and 0.8 MPa or less is more preferred, and 0.3 MPa or less is even more preferred.

[0028] When the hollow fiber membrane module used in the deoxygenation step is an internal reflux type, the outlet pressure outside the hollow fiber membranes (gas phase side) of the internal reflux type hollow fiber membrane module is kept at a reduced pressure, and the above-mentioned gas is flowed from the inlet side while the liquid is passed through the hollow fiber membranes (liquid phase side) to perform degassing. On the other hand, when the hollow fiber membrane module used in the degassing step is an external reflux type, the outlet pressure inside the hollow fiber membranes (gas phase side) of the external reflux type hollow fiber membrane module is kept at a reduced pressure, and the above-mentioned gas is flowed from the inlet side while the liquid is passed through the hollow fiber membranes (liquid phase side). In either case, it is preferable that the liquid phase side is the skin layer (dense layer) and the gas phase side is a layer with fine pores (porous layer).

[0029] There are no particular restrictions on the temperature of the alcoholic beverage during deoxygenation, but a temperature of 10°C or higher is preferred, 20°C or higher is more preferred, and a temperature of 50°C or lower is preferred, 40°C or lower is more preferred.

[0030] In the deoxidation step, carbon dioxide gas, or carbon dioxide gas and an inert gas, may be flowed into the gas phase inside the hollow fiber membranes of the hollow fiber membrane module from the module inlet side (upstream side). The pressure at which the carbon dioxide gas, or carbon dioxide gas and an inert gas, is flowed may be any pressure that can maintain a negative pressure in the gas phase. In other words, the pressure at which the carbon dioxide gas, or carbon dioxide gas and an inert gas are flowed into the gas phase may be lower than the pressure at which the gas phase is evacuated by a vacuum pump.

[0031] The total pressure of the gas in the gas phase portion may be a negative pressure (less than 0 atmospheres in gauge pressure), preferably -0.3 atmospheres (gauge pressure) or less, more preferably -0.5 atmospheres (gauge pressure) or less, and although there is no lower limit, it is preferably -1 atmosphere (gauge pressure) or more. In the present invention, when it is necessary to convert the unit from atmosphere (atm) to "Pa", standard atmospheric pressure (101,325 Pa) is used.

[0032] When the gas flowing into the gas phase is carbon dioxide, it preferably accounts for 5 mol% or more of the flowing gas, more preferably 50 mol% or more, even more preferably 80 mol% or more, and particularly preferably 100 mol%, i.e., substantially only carbon dioxide. However, even if the flowing gas contains gases other than carbon dioxide, the proportion of oxygen gas is 20 mol% or less, preferably 10 mol% or less, and more preferably 0 mol%. Note that "carbon dioxide only" means that the total pressure and the carbon dioxide partial pressure are equal, and "substantially carbon dioxide only" means that all gases other than carbon dioxide (air) have been completely removed, except for the case where residual air remains at start-up and the gas is not completely carbon dioxide.

[0033] On the other hand, when the gas flowing into the gas phase is carbon dioxide gas and an inert gas, it is more preferable that the oxygen content of the flowing gas is 50 mol % or more, even more preferably 80 mol % or more, and particularly preferably 100 mol %, i.e., substantially only a mixture of carbon dioxide gas and nitrogen gas. However, even if the flowing gas contains gases other than the mixture of carbon dioxide gas and nitrogen gas, the proportion of oxygen gas is 20 mol % or less, preferably 10 mol % or less, and more preferably 0 mol %. Note that "only a mixture of carbon dioxide gas and an inert gas" means that the total pressure is equal to the sum of the partial pressure of carbon dioxide gas and the partial pressure of the inert gas, and "substantially only a mixture of carbon dioxide gas and an inert gas" means that all gases (air) other than the "mixture of carbon dioxide gas and an inert gas" have been completely removed, except for the case where residual air remains at the time of startup and the mixture is not entirely made up of the mixture of carbon dioxide gas and an inert gas. Furthermore, the mixing ratio of carbon dioxide gas and inert gas in the mixed gas is not particularly limited and can be any ratio, but the ratio of the carbon dioxide gas partial pressure to the total pressure is preferably in the range of 0.1 or more, and preferably less than 1.

[0034] Here, examples of the inert gas include nitrogen gas (nitrogen molecules) and gases (molecules) made of rare gas elements such as helium, neon, and argon, with nitrogen gas being preferred.

[0035] In this way, by maintaining the gas phase at negative pressure and removing (deoxygenating) the dissolved oxygen (molecules) in the liquid phase, and flowing carbon dioxide gas, or carbon dioxide gas and an inert gas, into the gas phase to prevent the reduction of dissolved carbon dioxide in the liquid phase, it is possible to suppress the reaction of oxidizing enzymes and inhibit reactions with oxidizable substances.In this process, by preventing the reduction of the amount of dissolved carbon dioxide, it is possible to maintain the freshness and aroma (fragrance) of the alcoholic beverage, and in particular the "ginjo aroma" which is considered to be a desirable aroma in brewed alcoholic beverages such as sake. The ratio of the amount of dissolved carbon dioxide after the deoxygenation step to the amount of dissolved carbon dioxide before the treatment is, by mass, preferably 1 / 500 or more, more preferably 1 / 100 or more, even more preferably 1 / 50 or more, particularly preferably 1 / 2 or more, and most preferably 0.8 or more, and although there is no upper limit specified, it can be 1 or less.

[0036] The amount of dissolved oxygen in alcoholic beverages, preferably undiluted alcohol, after the deoxygenation step is not particularly limited, but is preferably 10 ppm or less, more preferably 4 ppm or less. Since a lower amount is preferable, the lower limit is not particularly limited, but may be preferably 0.01 ppm or more, more preferably 0.5 ppm or more.

[0037] In the deoxygenation process, the gas flow rate on the gas side per hollow fiber membrane module may be adjusted appropriately within a range of 0.1 to 10 times the flow rate of the liquid flowing through the set module, but it is preferable to adjust it appropriately within a range of 1 to 3 times.

[0038] The pressure of the gas flowing into the gas phase portion may be adjusted by appropriately pressurizing it with a pump or the like, but when the gas is provided in a pressure vessel such as a cylinder, it is preferable to use the gas by reducing the pressure inside the cylinder via a pressure adjustment valve and adjusting it to the required pressure as appropriate. In this case, it is sufficient that the pressure is negative at the outlet of the gas phase side of the hollow fiber membrane module. It is also preferable that the gas is caused to flow in the gas phase side of the degassing module in the opposite direction to the flow in the liquid phase side.

[0039] An example of an apparatus that can be used in the present invention is shown in Figure 1. The apparatus is equipped with a hollow fiber membrane module, and contains an alcoholic beverage flowing through the liquid phase and carbon dioxide gas, or carbon dioxide gas and an inert gas, while maintaining a negative pressure in the gas phase.

[0040] First, the alcoholic beverage is supplied to a pressure-resistant tank 4 and stored while its temperature is appropriately adjusted. With two-way valve 17 closed, nitrogen gas is supplied to tank 4 through gas piping 3 from nitrogen gas cylinder 1 while adjusting the pressure with pressure adjustment valve 2, thereby extruding the alcoholic beverage stored in tank 4. Next, the alcoholic beverage is introduced into hollow fiber membrane module 16 for deoxidation through liquid-passing piping 5 from its liquid-phase side inlet 6.

[0041] Next, while keeping the two-way valve 17 closed, carbon dioxide gas is introduced into the hollow fiber membrane module 16 from the gas phase inlet 12 via piping 11 while adjusting the pressure of the pressure regulating valve 10 from the carbon dioxide gas cylinder 9, and the vacuum pump 15 is operated to maintain a negative pressure on the pressure gauge P3, and the pressure inside the module is reduced through piping 14 from the gas phase outlet 13 of the hollow fiber membrane module 16, thereby maintaining or suppressing the loss of dissolved carbon dioxide in the alcoholic beverage passed through the liquid phase side of the hollow fiber membrane module 16 and deoxygenating the dissolved oxygen. After a predetermined time has elapsed, the two-way valve 17 is opened, and the deoxygenated alcoholic beverage can be stored in a storage container through the supply port 18. It is also possible to provide a cooling device to some or all of the hollow fiber membrane module 16 and the liquid passage pipes 5 and 8.

[0042] The present invention is not particularly limited to the type of alcoholic beverage, and may be applied, for example, to beverages with an alcohol content of 1% or more, including those that can be diluted to make a beverage with an alcohol content of 1% or more, or powdered products that can be dissolved to make a beverage with an alcohol content of 1% or more. Sparkling alcoholic beverages, such as beer and happoshu, brewed alcoholic beverages, such as refined alcoholic beverages like sake and fruit wine, distilled alcoholic beverages, such as whiskey and shochu, and blended alcoholic beverages are all acceptable, but it is particularly preferred to apply the invention to "namazake" (a general term for alcoholic beverages that have never been subjected to a heating treatment at around 60°C called "pasteurization," particularly for sake), which is said to have a strong "ginjo aroma (fruity)."

[0043] As described above, according to the production method of the present invention, not only is the amount of dissolved oxygen in alcoholic beverages reduced by the hollow fiber membrane module, but the gas phase is deoxygenated under atmospheric pressure with a flow of gas containing carbon dioxide, thereby suppressing the removal of aroma. As a result, deterioration of aroma, taste, and color can be prevented. More preferably, alcoholic beverages (undiluted sake) can maintain their freshness while retaining their aroma, particularly the "ginjo aroma" that is considered a desirable aroma in brewed alcoholic beverages such as sake. [Example]

[0044] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0045] (Measurement of dissolved gases) The amount of dissolved oxygen was measured using a "B-506" manufactured by Iijima Electronics Co., Ltd. The amount of dissolved carbon dioxide was measured using a "Dissolved Oxygen (CO2) Meter" manufactured by Mettler Toledo.

[0046] (Sensory evaluation method and evaluation criteria) In the examples, the evaluation methods were as follows, unless otherwise specified. The sensory evaluation consisted of evaluation of ginjo aroma (fruit-like) and freshness. "Ginjo aroma" and "freshness" are defined as the evaluation of "Ginjo aroma, fruity" (codes 110, 120) and "14. Mouthfeel" (code 1460) in Table 1, respectively, from Utsunomiya Jin and three others, "Quality Evaluation Terms and Standard Samples for Aroma and Flavor in Sensory Evaluation Analysis of Sake," [online], 2006, National Research Institute of Brewing, pp. 3 and 4, accessed December 7, 2020, http: / / www.nrib.go.jp / data / pdf / seikoumihou.pdf.

[0047] The results of the sensory evaluation were compiled by a panel of five trained people using standard samples (50 ml polypropylene centrifuge tubes containing 3 g / liter of isoamyl acetate and 1.2 g / liter of ethyl caproate).

[0048] The intensity of the "Ginjo aroma, fruity" (codes 110, 120) was evaluated on a six-point scale: 1 (not noticeable), 2 (hardly noticeable), 3 (slightly noticeable), 4 (slightly noticeable), 5 (strong), and 6 (very strong), and recorded in the "Ginjo aroma" column in Table 1.

[0049] The intensity of the perceived "mouthfeel" (code 1460) was rated on a six-point scale: 1 (not noticeable), 2 (barely noticeable), 3 (slightly noticeable), 4 (slightly noticeable), 5 (strong), and 6 (very strong), and recorded in the "Freshness" column in Table 1.

[0050] Example 1 The hollow fiber membrane modules used were all "EF-020G-A30" manufactured by DIC Corporation (poly-4-methylpentene-1 resin hollow fiber membranes with an asymmetric membrane consisting of a skin layer (outer layer) and a porous layer (inner layer) with hollow fiber pore diameters of 5 to 20 nm). Prior to testing, the modules were washed with ultrapure water for 72 hours, then the inside of the modules were dried with sterile air. They were then washed with tap water (23°C) for 3 minutes.

[0051] Using the manufacturing apparatus shown in Figure 1, deoxygenation was performed under a carbon dioxide flow. Sake (Gekkeikan Co., Ltd.'s "Junmai Daiginjo Namashu" with a dissolved oxygen concentration (DO) of 8.2 ppm and a dissolved carbon dioxide concentration of 200 ppm before degassing) was charged into tank 4. With two-way valve 17 closed, pressure valve 3 was opened to adjust the flow rate of sake from tank 4 to 4 L / min. Furthermore, while operating vacuum pump 15 on the gas phase side, carbon dioxide (100% purity) was supplied from carbon dioxide cylinder 9 via pipe 11 into the hollow fiber membrane module through air inlet 12. The carbon dioxide supply was adjusted to a negative pressure (vacuum degree -88.025 kPa(g)) on the outlet 13 side, with the amount of air removed by the vacuum pump being supplied. Then, two-way valve 17 was opened, and the sake was deoxygenated in hollow fiber membrane module 15. The deoxygenated sake was poured into a storage container through supply port 18. The resulting sake (after vacuum degassing in a carbon dioxide gas stream, DO value 1.7 ppm, dissolved carbon dioxide concentration 196 ppm) was immediately subjected to a sensory evaluation. The results of the sensory evaluation are shown in Table 1.

[0052] Example 2 Sake was deoxygenated in the same manner as in Example 1, except that a cylinder 9 of a mixed gas of carbon dioxide and nitrogen gas (molar ratio N2:CO2 = 8.7:1.3) was used instead of the carbon dioxide gas cylinder 9. A sensory evaluation was performed on the resulting sake (after reduced pressure degassing treatment under a flow of carbon dioxide and nitrogen gas, DO value 1.0 ppm, dissolved carbon dioxide concentration 190 ppm). The results of the sensory evaluation are shown in Table 1.

[0053] (Comparative Example 1) Sake was deoxygenated in the same manner as in Example 1, except that pressure regulating valve 10 was closed and no gas was supplied. A sensory evaluation was performed on the resulting sake (after reduced pressure degassing treatment without gas flow, DO value 1.7 ppm, dissolved carbon dioxide concentration 0.1 ppm). The results of the sensory evaluation are shown in Table 1.

[0054] [Table 1]

[0055] The above sensory evaluation analysis showed that in Comparative Example 1, deoxygenation was performed by vacuum degassing using a hollow fiber membrane module to reduce the dissolved oxygen, resulting in a decrease in both "ginjo aroma, fruity" and "freshness." In contrast, in Examples 1 and 2, while only carbon dioxide gas was circulated through the gas phase side of the hollow fiber membrane module, deoxygenation was performed by vacuum degassing within the gas phase to reduce the dissolved oxygen, which resulted in the suppression or maintenance of the decrease in "ginjo aroma, fruity" and the maintenance of both "freshness." [Explanation of symbols]

[0056] 1 Nitrogen gas cylinder (high-pressure container) 2 Pressure Regulating Valve 3 Nitrogen gas piping 4 Tanks (pressure-resistant storage vessels) 5 Piping for fluid passage 6 Module liquid phase inlet 7 Module liquid phase outlet 8 Fluid flow piping 9 Carbon dioxide cylinder (high pressure container) 10 Pressure Regulating Valve 11 Carbon dioxide gas intake port side piping 12 Module gas phase inlet (carbon dioxide gas inlet) 13 Module gas phase outlet (carbon dioxide gas outlet) 14 Carbon dioxide gas outlet side piping 15 Vacuum pump 16 Hollow fiber membrane module 17 Two-way valve 18 Supply port P1 Pressure Gauge P2 pressure gauge F1 flow meter P3 Pressure Gauge

Claims

1. The method includes a step of using a degassing device equipped with a hollow fiber membrane module to pass alcoholic beverages through a liquid phase portion of the hollow fiber membrane module and passing carbon dioxide gas and an inert gas through the liquid phase portion of the hollow fiber membrane module while maintaining a negative pressure in the gas phase portion, A method for producing alcoholic beverages, wherein the carbon dioxide gas and the inert gas account for 50 mol % or more of the gas flowing into the gas phase portion, and the ratio of the partial pressure of the carbon dioxide gas to the total pressure of the gas flowing into the gas phase portion is 0.1 or more and less than 1.

2. 2. The method for producing alcoholic beverages according to claim 1, wherein the ratio of the amount of dissolved carbon dioxide after the treatment to the amount of dissolved carbon dioxide before the treatment is in the range of 1 / 500 or more on a mass basis.

3. 3. The method for producing alcoholic beverages according to claim 1 or 2, wherein the amount of dissolved oxygen in the alcoholic beverage obtained through the steps is in the range of 10 ppm or less.

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