Sake production methods

Abstract

To provide a method for producing sake that undergoes enzyme inactivation and sterilization treatment while suppressing the decline in freshness and the fruity characteristics typical of sake. [Solution] A method for producing sake, which includes a step of treating sake with an alternating high-electric field.

Description

Technical Field

[0001] The present invention relates to a method for producing Japanese sake.

Background Art

[0002] In the production process of clear liquors such as Japanese sake, a step of heat-treating Japanese sake (pasteurization step) may be performed for enzyme inactivation and sterilization of harmful bacteria. The heat treatment of Japanese sake is carried out using a heat exchanger or the like (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when heat-treating Japanese sake using a heat exchanger or the like, freshness and the fruity flavor characteristic of Japanese sake may decrease.

[0005] An object of the present invention is to provide a method for producing Japanese sake subjected to enzyme inactivation treatment and sterilization treatment while suppressing a decrease in freshness and the fruity flavor characteristic of Japanese sake.

Means for Solving the Problems

[0006] The present invention relates to a method for producing Japanese sake, including a step of subjecting Japanese sake to alternating high electric field treatment. According to this production method, by subjecting Japanese sake to alternating high electric field treatment, Japanese sake subjected to enzyme inactivation treatment and sterilization treatment can be obtained while suppressing a decrease in freshness and the fruity flavor characteristic of Japanese sake.

[0007] The distance between electrodes in AC high-field processing may be 1.5 to 2.5 mm. The applied voltage per electrode distance in AC high-field processing may be 2200 to 6600 V / cm. The voltage application time in AC high-field processing may be 0.80 to 3.00 seconds.

[0008] The AC high-field treatment step may be a step of treating sake containing caproic acid and ethyl caproate, where the ratio of caproic acid content (mg / L) to ethyl caproate content (mg / L) is 5 or more, with an AC high-field treatment. In this case, the effects of the present invention become even better.

[0009] The present invention relates to a method for performing enzyme deactivation and sterilization treatment on sake while suppressing a decrease in the freshness and characteristic fruitiness of sake, the method comprising the step of treating sake with an alternating high-electric field.

[0010] The present invention includes, for example, the following: [1] A method for producing sake, including a step of treating sake with an alternating high-electric field. [2] The method for producing sake according to [1], wherein the distance between electrodes in the AC high-electric field treatment is 1.5 to 2.5 mm. [3] A method for producing sake according to [1] or [2], wherein the applied voltage per unit distance between electrodes in the AC high-electric field treatment is 2200 to 6600 V / cm. [4] A method for producing sake according to any one of [1] to [3], wherein the voltage application time in the AC high electric field treatment is 0.80 to 3.00 seconds. [5] A method for producing sake according to any one of [1] to [4], wherein the step of treating sake with an alternating high electric field is a step of treating sake containing caproic acid and ethyl caproate, wherein the ratio of the content of caproic acid (mg / L) to the content of ethyl caproate (mg / L) is 5 or more. [6] A method for performing enzyme deactivation and sterilization treatment on sake while suppressing a decrease in the freshness and characteristic fruitiness of sake, the method comprising a step of treating sake with an alternating high-electric field. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a method for producing sake that has undergone enzyme inactivation and sterilization treatment while suppressing a decrease in freshness and the fruity characteristics typical of sake. [Brief explanation of the drawing]

[0012] [Figure 1] The graph shows the results of the evaluation test of the sterilization effect of fire-damaged bacteria in the examples, with (a) showing the evaluation results of the sterilization effect by AC high-electric field treatment and (b) showing the evaluation results of the sterilization effect by heat exchanger treatment. [Modes for carrying out the invention]

[0013] The embodiments for carrying out the present invention will be described in detail below. However, the present invention is not limited to the following embodiments.

[0014] The sake manufacturing method according to this embodiment includes a step of treating sake with an alternating high-electric field (alternating high-electric field treatment step).

[0015] In this specification, "Japanese sake" means sake made in Japan using only rice produced in Japan as the raw material for the rice and rice koji. Japanese sake (sake) may be a specially designated sake that meets the "Standards for Labeling the Manufacturing Method and Quality of Sake" as stipulated by a National Tax Agency notification (standards for labeling alcoholic beverages as stipulated in the "Act on the Preservation of Liquor Tax and Liquor Industry Associations, etc."). Examples of specially designated sake include ginjo-shu, daiginjo-shu, junmai-shu, junmai ginjo-shu, junmai daiginjo-shu, tokubetsu junmai-shu, honjozo-shu, and tokubetsu honjozo-shu.

[0016] The sake to be subjected to AC high electric field treatment may be raw sake that has not been pasteurized, or may be raw sake that has been pasteurized at least once. The sake to be subjected to AC high electric field treatment may be the liquid (upper tank sake) obtained by squeezing the moromi, and may be sake (unfiltered raw sake) that has not been filtered, pasteurized, or diluted with water, or may be sake (raw sake) obtained by filtering the liquid obtained by squeezing the moromi and that has not been pasteurized or diluted with water, or may be sake (raw liquor) obtained by filtering the liquid obtained by squeezing the moromi, then pasteurizing it, and that has not been diluted with water, or may be sake that has been filtered, pasteurized, and diluted with water.

[0017] The AC high electric field treatment can be carried out, for example, using the apparatus described in Japanese Patent No. 4495647. An example of an AC high electric field treatment apparatus is an apparatus comprising a liquid feeding means for feeding sake to an energization unit, an energization unit for subjecting the sake to AC high electric field treatment, a cooling device for cooling the sake subjected to AC high electric field treatment, and a pressure maintaining valve for taking out the cooled sake subjected to high electric field treatment out of the system. The AC high electric field treatment apparatus may further comprise a preheating device for preheating the sake before subjecting it to AC high electric field treatment. The AC high electric field treatment apparatus may be such that each device and means are connected by piping and constitute a closed system by itself.

[0018] A pump is used as the liquid feeding means. As the pump, it can be appropriately selected and used from commonly used plunger pumps, cylinder pumps, rotary pumps, etc.

[0019] As the preheating device, a heat exchange plate (for heating) can be used.

[0020] The energization unit includes one or more pairs of electrodes. The electrodes in the energization unit are connected to an AC power supply. A flow path through which the liquid supplied from the liquid supply port flows is formed between a pair of electrodes in the energization unit. Japanese sake continuously flows through the flow path of the energization unit. By subjecting the flowed Japanese sake to AC high electric field treatment within the energization unit, it is possible to perform sterilization treatment on the Japanese sake by self-heating due to Joule heating and physical damage due to the high electric field, and enzyme inactivation treatment by heat shock due to rapid heating. The electrodes in the energization unit may be covered with an insulator. The energization unit may be made into a closed system by covering it with an insulator or the like.

[0021] The type of the electrode is a metal having electrical conductivity, and from the viewpoint of preventing deterioration such as corrosion of the electrode, it is preferably made of titanium, platinum, or stainless steel. The electrodes of the energization unit can be stacked in multiple layers by stacking a plurality of insulators. The one or more pairs of electrodes may be one or more pairs of metal parallel plate electrodes (electrodes of parallel plates).

[0022] The distance between the electrodes (the thickness between the electrodes) may be 0.9 mm or more, 1.0 mm or more, 1.2 mm or more, 1.4 mm or more, 1.5 mm or more, 1.6 mm or more, or 1.8 mm or more, and may be 4.5 mm or less, 4.0 mm or less, 3.5 mm or less, 3.0 mm or less, 2.8 mm or less, 2.6 mm or less, 2.5 mm or less, 2.4 mm or less, or 2.2 mm or less. The distance between the electrodes may be 1.5 - 2.5 mm, 1.8 - 2.2 mm, or may be exactly 2 mm.

[0023] The applied voltage per electrode distance may be 2000V / cm or more, 2100V / cm or more, 2200V / cm or more, 2300V / cm or more, 2400V / cm or more, 2600V / cm or more, 2700V / cm or more, or 2800V / cm or more, and may be 7000V / cm or less, 6800V / cm or less, 6600V / cm or less, 6400V / cm or less, 6200V / cm or less, or 6100V / cm or less. The applied voltage per electrode distance may be 2200~6600V / cm, 2800~6100V / cm, or 2000-3000V / cm.

[0024] The treatment temperature in AC high-electric field treatment may be 50°C or higher, 55°C or higher, 60°C or higher, 62°C or higher, or 64°C or higher, and may be 80°C or lower, 75°C or lower, or 70°C or lower, as this further improves the sterilization effect. The treatment temperature in AC high-electric field treatment may be less than 70°C, 68°C or lower, or 66°C or lower, as this further improves the enzyme inactivation effect. The treatment temperature in AC high-electric field treatment may be 60°C or higher but less than 70°C, or 64-66°C, as this further improves both the sterilization effect and the enzyme inactivation effect. "Treatment temperature" refers to the liquid temperature (product temperature) of sake during AC high-electric field treatment.

[0025] The voltage application time may be within 3.00 seconds, within 2.90 seconds, within 2.80 seconds, within 2.70 seconds, or within 2.60 seconds, and may be 0.50 seconds or more, 0.60 seconds or more, 0.80 seconds or more, 1.00 seconds or more, 1.50 seconds or more, 2.00 seconds or more, 2.20 seconds or more, 2.40 seconds or more, or 2.50 seconds or more. The heating time may be 0.80 to 3.00 seconds, 1.50 to 3.00 seconds, 2.00 to 2.90 seconds, 2.40 to 2.80 seconds, or 2.58 seconds. The voltage application time may be the time to maintain the above processing temperature (heating time).

[0026] The power supply frequency may be 50 kHz or less, 20 kHz or less, or 10-20 kHz, or even 5 kHz or less, considering energy efficiency and corrosion resistance to electrodes.

[0027] The AC high-field treatment device cools the sake heated by Joule heating through a cooling means. A heat exchange plate (for cooling) can be used as the cooling means.

[0028] The sake, treated with an AC high-electric field, is removed from the system via a pressure-holding valve (pressure-regulating valve). The pressure can be adjusted using the liquid delivery means and the pressure-holding valve.

[0029] AC high-field processing may be performed under pressure. Pressurization can be achieved by controlling the pressurized gas, the water pressure of the liquid itself, the liquid delivery means (pump), and, if necessary, a pressure-holding valve.

[0030] When sake is subjected to AC high-electric field processing under pressure in an energizing unit, the pressure inside the energizing unit may be, for example, 0.67 to 0.9 MPa.

[0031] The AC high-field treatment process may be a process of treating sake containing caproic acid and ethyl caproate with an AC high-field. Caproic acid is a compound also known as hexanoic acid. Ethyl caproate is a compound also known as ethyl hexanoate.

[0032] The caproic acid content in sake subjected to AC high-electric field treatment may be 10 mg / L or more, 20 mg / L or more, 30 mg / L or more, 35 mg / L or more, 40 mg / L or more, 50 mg / L or more, 60 mg / L or more, 70 mg / L or more, or 75 mg / L or more, based on the total amount of sake, and may be 100 mg / L or less, 90 mg / L or less, or 85 mg / L or less. The caproic acid content in sake subjected to AC high-electric field treatment can be measured, for example, by GC-MS analysis by solvent extraction.

[0033] The ethyl caproate content in sake subjected to AC high-electric field treatment may be 1 mg / L or more, 2 mg / L or more, 3 mg / L or more, 4 mg / L or more, 5 mg / L or more, 6 mg / L or more, 7 mg / L or more, 8 mg / L or more, 9 mg / L or more, or 10 mg / L or more, based on the total amount of sake, and may be 30 mg / L or less, 25 mg / L or less, 20 mg / L or less, 15 mg / L or less, or 12 mg / L or less. The ethyl caproate content in sake subjected to AC high-electric field treatment can be measured by solid-phase microextraction (SPME).

[0034] In sake subjected to AC high-electric field treatment, the ratio of caproic acid content (mg / L) to ethyl caproate content (mg / L) (hereinafter, "caproic acid / ethyl caproate") may be 1 or more, 2 or more, 3 or more, or 4 or more. From the viewpoint of further enhancing the effect of suppressing the decrease in freshness and the fruity taste characteristic of sake, and from the viewpoint of further improving the fruity aroma, it may be 5 or more, 6 or more, 7 or more, 8 or more, 10 or more, 12 or more, or 15 or more. The caproic acid / ethyl caproate ratio may be 25 or less, 20 or less, 18 or less, 16 or less, 14 or less, 12 or less, 10 or less, or 9 or less.

[0035] By treating sake containing caproic acid with an alternating high-electric field in the presence of ethyl caproate, the reaction between caproic acid and the alcohol (ethanol) present in the sake to produce ethyl caproate is accelerated. This accelerated reaction effect becomes more pronounced when the respective caproic acid and ethyl caproate content and / or the caproic acid / ethyl caproate ratio are within the aforementioned numerical range. As a result of this reaction acceleration, the amount of fruit-like aroma components containing ethyl caproate can be increased. This makes it easier to achieve the effect of increasing the amount of fruit-like aroma components containing ethyl caproate ultimately contained in the sake, and / or suppressing the decrease in the amount of fruit-like aroma components due to enzyme inactivation and sterilization treatments.

[0036] The caproic acid content in sake after AC high-electric field treatment may be 10 mg / L or more, 25 mg / L or more, 50 mg / L or more, or 60 mg / L or more, based on the total amount of sake, and may be 100 mg / L or less, 80 mg / L or less, or 70 mg / L or less. The caproic acid content in sake after AC high-electric field treatment can be measured by the method described above.

[0037] The ethyl caproate content in sake after AC high-field treatment may be, for example, 1 mg / L or more, 3 mg / L or more, or 4 mg / L or more, and may be 30 mg / L or less, 20 mg / L or less, 10 mg / L or less, 8 mg / L or less, or 6 mg / L or less. The ethyl caproate content in sake after AC high-field treatment can be measured by the method described above.

[0038] The method for producing sake can be carried out by conventional methods, except for the inclusion of an AC high-electric field treatment process.

[0039] The method for producing sake may further include a step of preparing the sake to be treated with the AC high-electric field treatment (preparation step) before the AC high-electric field treatment step. This step may further include a step of fermenting the brewing ingredients to obtain mash (fermentation step), and a step of separating the liquid fraction of the mash from the sake lees and collecting the liquid fraction (separation step), etc.

[0040] In the fermentation process, the brewing ingredients are fermented to obtain mash. The brewing ingredients include steamed rice, rice koji, yeast starter, and water. The steamed rice used in the brewing process may be steamed rice or mashed rice. The rice variety may be a variety that can be used for sake brewing, and may be sake-brewing rice or general-purpose rice, and may be non-glutinous rice or glutinous rice.

[0041] Rice koji is made by cultivating Aspergillus oryzae mold on steamed rice. There are no particular restrictions on the type of koji mold used, as long as it is suitable for sake production. The sake starter (shubo) can be made using conventional methods.

[0042] The brewing process involves adding the yeast starter, steamed rice, rice koji, and water to a fermentation tank. The brewing ingredients may be added all at once or in multiple stages.

[0043] The fermentation period for the mash may be, for example, 10 to 40 days, 15 to 40 days, or 20 to 30 days. The fermentation temperature for the mash may be, for example, 5 to 25°C, or 10 to 20°C.

[0044] After the fermentation process, sake lees are removed from the mash to obtain sake (pressed sake) as a liquid fraction. The separation of sake lees from the liquid fraction can be carried out by methods such as pressing and filtration.

[0045] The method for producing sake may further include, after the preparation step, at least one step selected from the following: a step of filtering the sake (filtration step), a step of heating the sake (pasteurization step), a step of storing the sake (storage step), a step of adjusting the alcohol content of the sake with water or the like (dilution step), and a step of bottling the sake (bottling step).

[0046] The filtration process may be a process of filtering the liquid fraction obtained by removing sake lees from the mash. The conditions for filtration are not particularly limited and can be carried out by conventional methods. The filtration process can be carried out using a filter that utilizes activated carbon and filters, etc. The sake may also be unfiltered sake that has not undergone this filtration process.

[0047] The pasteurization process is a process of sterilizing sake by maintaining it at a temperature of, for example, 60-65°C. The pasteurization process may be performed multiple times. The pasteurization process may be performed, for example, before the storage process and / or after the storage process.

[0048] In the storage process, sake is stored and aged. Storage conditions can be set appropriately depending on the type of sake, etc. The storage temperature may be, for example, 15-20°C. By performing the AC high-electric field treatment process before the storage process, changes in amino acid composition due to storage can be suppressed, and sweetness can be suppressed.

[0049] In the dilution process, the alcohol content of the sake is adjusted with water or other liquids. The dilution process may be performed as needed. The sake may be undiluted sake (genshu). The alcohol content of the sake may be less than 22 v / v%, for example, 13-16 v / v%, or 15-16 v / v%. The sake may also be a low-alcohol type sake with an alcohol content of less than 10 v / v%.

[0050] Materials used for containers in the packaging process include glass, plastic, paper, ceramics, wood, and combinations thereof. Types of containers include cups, paper cartons, pouches, bottles, plastic containers, and barrels.

[0051] The method for manufacturing sake may further include other processes, such as a process of blending it with other sake (blending process).

[0052] The AC high-field treatment process can be carried out, for example, at any stage after the preparation process and before the bottling process. The AC high-field treatment process may be performed in place of the pasteurization process in the sake manufacturing method. If the pasteurization process is performed multiple times (e.g., before and after the storage process), the AC high-field treatment process may be performed in place of at least one of the multiple pasteurization processes.

[0053] The method according to this embodiment includes an AC high-electric field treatment step, which allows for the production of sake that has undergone enzyme inactivation and sterilization treatment while suppressing a decrease in freshness and the fruity characteristics characteristic of sake. Because the sake obtained by the method according to this embodiment has undergone enzyme inactivation and sterilization treatment, it can suppress the deterioration of sweetness caused by changes in amino acid composition during storage, and harmful bacteria are killed. Examples of harmful bacteria include spoilage bacteria.

[0054] One embodiment of the present invention provides a method for enzyme deactivation and sterilization of sake, which includes a step of treating sake with an alternating high electric field. This method makes it possible to deactivate enzymes and sterilize sake while suppressing a decrease in the freshness and characteristic fruitiness of sake. Therefore, one embodiment of the present invention provides a method for enzyme deactivation and sterilization of sake, which includes a step of treating sake with an alternating high electric field, while suppressing a decrease in the freshness and characteristic fruitiness of sake (or a method for suppressing a decrease in the freshness and characteristic fruitiness of sake due to enzyme deactivation and sterilization).

[0055] The sake obtained by the manufacturing method according to this embodiment undergoes enzyme deactivation and sterilization treatment while suppressing the reduction of fruit-like aroma components in the sake. Therefore, as one embodiment of the present invention, a method is also provided for performing enzyme deactivation and sterilization treatment on sake while suppressing the reduction of fruit-like aroma components in sake (or a method for suppressing the reduction of fruit-like aroma components in sake due to enzyme deactivation and sterilization treatment), which includes a step of treating sake with an alternating high electric field.

[0056] Examples of fruit-like aroma components in sake include esters such as ethyl caproate, isoamyl acetate, ethyl acetate, ethyl butyrate, ethyl caprylate, ethyl caprate, and isobutyl acetate. The sake obtained by the production method according to this embodiment has a suppressed decrease in the amount of ethyl caproate, or an increased amount of ethyl caproate. Therefore, as one embodiment of the present invention, a method is provided for enzyme deactivation and sterilization treatment of sake, which includes a step of treating sake with an alternating high electric field, while suppressing a decrease in the amount of ethyl caproate or increasing the amount of ethyl caproate. [Examples]

[0057] The present invention will be described more specifically below based on examples. However, the present invention is not limited to the following examples.

[0058] The following test samples were prepared. Test Sample 1: Tosa Sake Brewery Co., Ltd. (Keigetsu CEL24 Junmai Daiginjo 50 Shiboritate Nama-zake): Characterized by its gorgeous aroma. Test sample 2: Chikuma Nishiki Sake Brewery Co., Ltd. (Kizan No. 2 Junmai Daiginjo Genshu)

[0059] [Sake production] Japanese sake (test sample) was subjected to AC high-field treatment or heat exchanger treatment to obtain sample liquids treated with either AC high-field treatment or heat exchanger treatment. The AC high-field treatment conditions and heat exchanger treatment conditions were as follows. The obtained sample liquids were used for enzyme activity measurement, amino acid analysis, aroma component measurement, and sensory evaluation.

[0060] AC high electric field processing conditions Distance between electrodes (thickness between electrodes): 2 mm Applied voltage: 2800~6100 (V / m) Processing temperature: 65℃ Heating time: 2.58 seconds

[0061] Heat exchanger processing conditions Processing temperature: 80℃ Heating time: 120 seconds

[0062] [Evaluation of Japanese sake] 1. Measurement of viable bacterial count The flammable bacteria (NBRC13118: Fructilactobacillus fructivorans, NBRC15886: Lactobacillus Hilgardii) were each removed from the plate and dissolved in physiological saline (PBS). 660After adjusting the concentration to 0.1, 1 mL of these was added to 200 mL of MRS liquid medium and incubated at 30°C for 7 days. The resulting culture solution was centrifuged (3000 rpm, 5 min, 4°C) and resuspended in 5 mL of PBS to obtain a suspension of *Cyperus rottensis* bacteria. The *Cyperus rottensis* suspension was added to sake (test sample 1) at a concentration of approximately 0.1 mL / L. The sake to which the *Cyperus rottensis* suspension was added was subjected to AC high-field treatment or heat exchanger treatment to obtain sample solutions (treated sample solutions) that had undergone AC high-field treatment or heat exchanger treatment. 100 μl of each sample solution was spread onto MRS agar medium and incubated at 30°C for 7 days, and the number of viable *Cyperus rottensis* bacteria in the resulting culture solution was measured.

[0063] Figure 1 shows the number of viable fire-dropping bacteria after AC high-electric field treatment and heat exchanger treatment. In Figure 1, "Initial" indicates the number of viable fire-dropping bacteria before treatment. As shown in Figure 1, it was confirmed that fire-dropping bacteria can be killed by AC high-electric field treatment as well as by heat exchanger treatment.

[0064] 2. Enzyme activity The enzyme activity of sample liquids treated with either AC high-electric field treatment or heat exchanger treatment was measured for test sample 1 (Keigetsu CEL24 Junmai Daiginjo 50 Shiboritate Nama-zake).

[0065] We measured α-amylase, saccharification capacity (glucoamylase + α-glucosidase), and acidic carboxypeptidase, which are commonly measured in sake, using their respective measurement kits (Kikkoman Biochemifa Co., Ltd.).

[0066] The results are shown in Table 1. The values ​​are expressed as a percentage with the enzyme activity of unpasteurized sake (test sample 1) set to 100%. [Table 1]

[0067] Both AC high-field treatment and heat exchanger treatment confirmed enzyme deactivation (residual enzyme activity less than 1%).

[0068] 3. Amino Acid Analysis The treated and untreated samples of test sample 1 were stored at 30°C for 4 weeks, and the changes in amino acid composition were confirmed by measuring the amounts of 40 amino acids before and after storage. The results are shown in Table 2.

[0069] We focused on and compared the amounts of amino acids that contribute to umami (glutamic acid, aspartic acid), bitterness (phenylalanine, tyrosine, arginine, isoleucine, methionine, lysine), and sweetness (glycine, alanine, threonine, proline, serine). Amino acids were analyzed using the ninhydrin method. The results are shown in Table 3.

[0070] [Table 2] [Table 3]

[0071] Because unpasteurized sake retains enzyme activity, its amino acid composition changes during storage, with a particularly increased amount of amino acids contributing to umami and sweetness (sweetness). On the other hand, samples treated with AC high-electric field and heat exchanger treatment showed no change in amino acid composition because the enzymes were deactivated.

[0072] 4. Measurement of aroma components 4-1. Measurement of aroma components of treated and untreated test sample 1 (Keigetsu) Eight milliliters of either the treated or untreated sample 1 were placed in a 20-milliliter SPME vial pre-filled with 3 g of NaCl, and the vial was sealed. After adding an internal standard with a microsyringe, the vial was shaken at 40°C for 15 minutes, exposing the SPME fiber to the headspace within the vial. After stopping the stirring, volatile components were adsorbed onto the fiber at 40°C for 30 minutes, followed by desorption at the inlet for 5 minutes, and analysis was performed by GC / MS. Aroma components known as esters, ginjo aroma, stale / stale odor, or aged aroma were measured. The results are shown in Table 4.

[0073] [Table 4]

[0074] The amount of fruit-like aroma components such as ethyl caproate and other esters (isoamyl acetate, ethyl acetate, ethyl butyrate, ethyl caprylate, ethyl caprate, and isobutyl acetate) decreased in heat exchanger treatment compared to unpasteurized sake, while the decrease was suppressed (ethyl caprylate and ethyl caprate) or increased (ethyl caproate, ethyl butyrate, and isobutyl acetate) in AC high-field treatment.

[0075] 4-2. Measurement of aroma components of treated and untreated test sample 2 (Kiyama) Aroma component measurements were performed on the treated and untreated samples of test sample 2 using the same method as described in "4-1. Aroma component measurement of treated and untreated samples of test sample 1 (Keigetsu)". The results are shown in Table 5.

[0076] [Table 5]

[0077] The amount of fruit-like aroma components (esters such as ethyl caproate) decreased in the heat exchanger-treated product compared to the untreated product, while the decrease was suppressed in the AC high-field-field-treated product.

[0078] 5. Sensory evaluation 5-1. Sensory evaluation of treated and untreated samples of test sample 1 (Keigetsu) A sensory evaluation was conducted on both the processed and unprocessed samples of test sample 1 by a panel of nine people. The unprocessed sample (raw sake) was scored 3 points (only the heated odor and heated taste were scored 1 point). Positive items included "freshness / juiciness," "fruity characteristic of sake," and "full-bodied flavor." Negative items included "bitterness," "heated odor / heated taste," and "harshness of alcohol." In addition, an "overall evaluation of aroma and flavor" was established. The sensory evaluation was based on a 5-point scale for intensity and preference, from "not perceived / dislike: 1" to "very strong / preference: 5." The panel consisted of trained panelists who had passed tests for the five tastes and aroma components.

[0079] [Table 6]

[0080] Compared to products treated with a high-field AC field, the sake treated with a heat exchanger had higher freshness (evaluation item "freshness / juiciness") and a fruity flavor characteristic of sake, as well as lower levels of heated odor and taste, resulting in a higher overall evaluation.

[0081] The AC high-field treated sake had a similar level of fruitiness characteristic of Japanese sake compared to unpasteurized sake, and received a high overall rating.

[0082] 5-2. Sensory evaluation of treated and untreated samples of test sample 2 (Kiyama) A sensory evaluation was conducted on both the processed and unprocessed samples of test sample 2 by a panel of six people. Unprocessed sake was scored out of 3 points (freshness / juiciness and sake-like fruitiness were scored out of 4 points, and heated odor / taste was scored out of 1 point). Positive items included "freshness / juiciness," "sake-like fruitiness," and "full-bodied flavor," while negative items included "bitterness," "heated odor / taste," "harshness of alcohol," "fatty acid odor," as well as "appearance" and "overall flavor evaluation." Intensity and preference were evaluated on a 5-point scale from "not perceived / dislike: 1" to "very strong / preference: 5." The panel consisted of trained individuals who had passed tests for the five tastes and aroma components. The results are shown in Table 7.

[0083] [Table 7]

[0084] Compared to products treated with a high AC electric field, the AC electric field-treated sake had higher freshness (evaluation item "freshness / juiciness") and a more characteristic sake fruitiness. The AC electric field-treated sake showed suppressed declines in freshness and sake fruitiness. Compared to products treated with a heat exchanger, the AC electric field-treated sake had lower heating odor and heating taste, and received a higher overall evaluation.

[0085] 6. Sake Model Liquid Test The sake model solution was prepared by diluting disinfectant alcohol to an alcohol content of 15% using Tosa Sake Brewing Co., Ltd.'s "Keigetsu CEL24 Junmai Daiginjo 50 Shiboritate Nama-zake" as a reference, and adding lactic acid to adjust the pH to 4.2. Furthermore, 0.5% glucose was added, and caproic acid and ethyl caproate were added to each test group in the amounts shown in Tables 8 and 9. Each model solution was subjected to heat exchanger or AC high-field treatment, and the amounts of ethyl caproate and caproic acid were measured along with the untreated sample. The amounts of ethyl caproate and caproic acid are shown in Tables 8 and 9, respectively. In Tables 8 and 9, ppm is synonymous with mg / L.

[0086] [Table 8] [Table 9]

[0087] It was confirmed using a model solution that when sake subjected to AC high-field treatment contains caproic acid and ethyl caproate, and the ratio of caproic acid content to ethyl caproate content (caproic acid / ethyl caproate) is above a predetermined level, the amount of ethyl caproate increases after AC high-field treatment.

Claims

1. A method for producing sake, including a step of treating sake with an alternating high-electric field.

2. The method for producing sake according to claim 1, wherein the distance between electrodes in the AC high-electric field treatment is 1.5 to 2.5 mm.

3. A method for producing sake according to claim 1 or 2, wherein the applied voltage per electrode distance in the AC high-electric field treatment is 2200 to 6600 V / cm.

4. The method for producing sake according to claim 1 or 2, wherein the voltage application time in the AC high-electric field processing is 0.80 to 3.00 seconds.

5. The method for producing sake according to claim 1 or 2, wherein the step of performing alternating high-field treatment is a step of performing alternating high-field treatment on sake containing caproic acid and ethyl caproate, wherein the ratio of the content of caproic acid (mg / L) to the content of ethyl caproate (mg / L) is 5 or more.

6. A method for performing enzyme deactivation and sterilization treatment on sake while suppressing the decline in freshness and the characteristic fruitiness of sake, A method comprising the step of treating sake with an alternating high-electric field.

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