Pasteurized soy sauce

Abstract

The purpose of the present invention is to provide a soy sauce that can be produced by the honjozo (traditional brewing) method and that, in addition to having the characteristic flavor of soy sauce, is resistant to heat-induced deterioration and exhibits an excellent aroma retention and storability. This purpose is achieved by, inter alia, a pasteurized soy sauce that contains at least 30 ppb phenethyl acetate; a pasteurized soy sauce that contains at least 30 ppb phenethyl acetate and exhibits a decline in phenethyl acetate of not more than 5% when aged for 1 week at 25°C; and their pasteurized honjozo soy sauces.

Description

[Technical Field]

[0001] The present invention relates to pasteurized soy sauce. [Background technology]

[0002] In the case of the honjozo method, soy sauce is produced by inoculating and cultivating a mixture of a protein raw material such as heat-denatured soybeans and a starchy raw material such as heat-gelatinized wheat with koji starter containing koji mold to produce koji, then placing the soy sauce koji thus obtained in salt water for lactic acid fermentation and aging to produce soy sauce moromi, then yeast fermenting and aging the soy sauce moromi thus obtained to produce matured moromi, then subjecting the matured moromi thus obtained to compression and filtration to produce raw soy sauce, and then pasteurizing the raw soy sauce thus obtained.

[0003] In the conventional soy sauce manufacturing method described above, the process is carried out continuously from soy sauce koji to the production of matured moromi. That is, yeast is added to the soy sauce moromi obtained from soy sauce koji by lactic acid fermentation or the like, and yeast fermentation or the like is carried out. Furthermore, yeast fermentation is carried out by adding yeast to the soy sauce moromi and leaving it for several weeks to several months. Furthermore, the maturation period for soy sauce moromi usually lasts for three months or more. Patent Document 1 listed below describes a method for shortening the maturation period, but it still requires one to two months.

[0004] Traditionally, soy sauce has been used by itself in cooking, and also as a processed soy sauce product, such as soup stock, sauce, and ponzu sauce, by mixing it with stock, vegetables, and fruits. It has also been used as a raw material for seasonings such as side dishes by mixing it with various ingredients and then retorting it. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Tokuhei 8-2264 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when soy sauce is used as described above, there are problems with thermal deterioration due to application of strong heat, and problems with aroma retention and shelf life due to storage over a certain period of time. In addition to these known methods, there are hardly any soy sauces known to date that are resistant to thermal deterioration and have excellent aroma retention and shelf life.

[0007] Therefore, the problem to be solved by the present invention is to provide a soy sauce that can be produced by the traditional brewing method, and that is resistant to thermal deterioration and has excellent aroma retention and storage properties in addition to the original flavor of soy sauce. [Means for solving the problem]

[0008] In order to solve the above problems, the present inventors reviewed the components and production method of soy sauce obtained by the traditional brewing method, and conducted repeated trial and error to find a soy sauce that is excellent as a seasoning. In the process, they discovered that soy sauce obtained by the method described in Patent Document 1 contains a very small amount of phenethyl acetate in addition to ethyl decanoate and ethyl octanoate. Phenethyl acetate is known to have a rose-like aroma. Furthermore, the content of phenethyl acetate in commercially available soy sauce is below the lower limit of detection.

[0009] Therefore, the present inventors further repeated trial and error to find conditions for increasing the amount of phenethyl acetate, and found that the phenethyl acetate content increases in the early stages of yeast fermentation, and that the phenethyl acetate content decreases once the yeast fermentation period has reached a certain level.

[0010] Based on these findings, the researchers pasteurized a yeast fermentation product that had reached a sufficient phenethyl acetate content, and surprisingly succeeded in producing pasteurized soy sauce that could be stored while maintaining the phenethyl acetate content.

[0011] Finally, the present inventors have succeeded in creating a pasteurized soy sauce containing a predetermined amount of phenethyl acetate. The present invention has been completed based on these findings and successful examples.

[0012] Thus, according to one aspect of the present invention, there is provided: [1] Pasteurized soy sauce containing 30 ppb or more of phenethyl acetate. [2] Pasteurized soy sauce containing 30 ppb or more of phenethyl acetate and in which the reduction rate of phenethyl acetate is 5% or less when aged for one week at 25°C. [3] The pasteurized soy sauce according to [1] or [2], wherein the soy sauce is honjozo soy sauce. [4] A step of subjecting the soy sauce koji to lactic acid fermentation by soy sauce lactic acid bacteria to a solid-liquid separation treatment to obtain a soy sauce moromi liquid; A step of subjecting the soy sauce moromi soup to a pasteurization treatment or an enzyme inactivation treatment to obtain a pasteurized soy sauce moromi soup; a step of subjecting the pasteurized soy sauce moromi liquid to yeast fermentation using soy sauce yeast to obtain a phenethyl acetate-containing soy sauce; A method for producing phenethyl acetate-containing soy sauce, comprising: [Effects of the Invention]

[0013] According to the pasteurized soy sauce of one embodiment of the present invention, the phenethyl acetate contained therein can improve the flavor of ingredients and cooked foods. Since the pasteurized soy sauce of one embodiment of the present invention can be produced by the traditional brewing method, it can be produced industrially together with or in place of commercially available soy sauce. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a graph showing the results of measuring phenethyl acetate during yeast fermentation of liquid-fermented soy sauce carried out in Example 1, as described below. [Figure 2]FIG. 2 is a graph showing the results of measuring phenethyl acetate for samples of the test group with and without pasteurization carried out in Example 2, as described in Example 1 below. DETAILED DESCRIPTION OF THE INVENTION

[0015] Each aspect of the present invention will be described in detail below, but the present invention is not limited to the details of these items and can take various forms as long as the object of the present invention is achieved.

[0016] Unless otherwise specified, each term in this specification is used in the sense commonly used by those skilled in the art and should not be construed as having an unduly limiting meaning. Furthermore, the speculations and theories made in this specification are based on the inventors' knowledge and experience to date, and therefore the present invention is not limited solely to such speculations and theories.

[0017] "Content" is synonymous with concentration and refers to the percentage of the amount of a component relative to the total amount of soy sauce. However, the total amount of the component content cannot exceed 100%. The term "ppm" is a unit as it is commonly known, specifically 1 ppm is 1 / 10 6 and 1 mg / L (w / v). The term "ppb" is a unit as it is commonly known, specifically 1 ppb is 1 / 10 9 This is equivalent to 1 ng / g in grams. The term "and / or" means any one or any or all combinations of two or more of the associated listed items. The "to" in a numerical range includes the preceding and following numerical values; for example, "0% to 100%" means a range greater than or equal to 0% and less than or equal to 100%. "More than" and "less than" mean the lower and upper limits, respectively, excluding the preceding numerical value; for example, "more than 1" means a numerical value greater than 1, and "less than 100" means a numerical value less than 100. "Comprising" means that elements other than those explicitly stated as being included can be added (same meaning as "comprising at least"), but also encompasses "consisting of" and "consisting essentially of." That is, "comprising" can mean including the explicitly stated elements and any one or more elements, consisting of the explicitly stated elements, or consisting essentially of the explicitly stated elements. Elements include limitations such as ingredients, steps, conditions, and parameters. "Flavor" refers to the aroma (retronasal) that escapes from the oral cavity to the nose when a food is held in the mouth, the taste (taste) that is felt on the tongue when a food is held in the mouth, or both.

[0018] The number of digits in an integer value matches the number of significant digits. For example, 1 has one significant digit, and 10 has two significant digits. Also, the number of digits after the decimal point matches the number of significant digits in a decimal value. For example, 0.1 has one significant digit, and 0.10 has two significant digits.

[0019] The pasteurized soy sauce of one embodiment of the present invention is a pasteurized soy sauce containing a predetermined amount of phenethyl acetate. The pasteurized soy sauce of one embodiment of the present invention has the original flavor of soy sauce, but is less susceptible to thermal deterioration than conventional soy sauces due to the predetermined amount of phenethyl acetate. The effect of phenethyl acetate, which is less susceptible to thermal deterioration and has excellent aroma retention and storage properties, and which can consequently improve the flavor of the soy sauce itself and / or the flavor of ingredients and cooked foods, is sometimes referred to as a "flavor-improving effect."

[0020] Soy sauce (also called shoyu or soy sauce) is what is commonly known as a seasoning. Soy sauce is defined, for example, in the Ministry of Agriculture, Forestry and Fisheries' Notification "Soy Sauce Quality Labeling Standards" and "Japanese Agricultural Standards for Soy Sauce."

[0021] Phenethyl acetate is a compound represented by the following formula (I), as is commonly known: [ka] (I) It is a compound having the structure shown below.

[0022] The content of phenethyl acetate in the pasteurized soy sauce of one embodiment of the present invention is an amount sufficient to achieve a flavor-improving effect, specifically, 30 ppb or more. From the viewpoint of achieving an excellent flavor-improving effect, it is preferably 50 ppb or more, and more preferably 100 ppb or more. However, phenethyl acetate itself has a rose-like aroma, and the aroma threshold is said to be approximately 3,000 ppb. Therefore, if the phenethyl acetate content is sufficiently high, specifically, if it contains 20,000 ppb or more, it may impart an undesirable floral aroma to the pasteurized soy sauce when consumed. Therefore, the upper limit of the phenethyl acetate content is preferably less than 20,000 ppb, more preferably 15,000 ppb or less, even more preferably 10,000 ppb or less, and even more preferably 3,000 ppb or less.

[0023] As described above, the content of phenethyl acetate is sufficient as long as it is 30 ppb or more, but in order to exert a more excellent flavor improving effect, it is preferably 30 ppb to 20,000 ppb, more preferably 30 ppb to 15,000 ppb, and even more preferably 30 ppb to 3,000 ppb. Note that "30 ppb to 3,000 ppb of phenethyl acetate" means, for example, 3,000 ng to 300,000 ng (= 300 μg) of phenethyl acetate per 100 ml of pasteurized soy sauce.

[0024] The pasteurized soy sauce of one embodiment of the present invention exhibits a flavor-improving effect not found in conventional soy sauces due to the phenethyl acetate content being in the above-mentioned range. On the other hand, the flavor-improving effect of phenethyl acetate can be masked by 2-ethyl-6-methylpyrazine, which is inherently contained in conventional soy sauces. Therefore, the content of 2-ethyl-6-methylpyrazine in the pasteurized soy sauce is, for example, an amount that does not suppress the flavor-improving effect of phenethyl acetate, preferably 50 ppb or less, more preferably 20 ppb or less, even more preferably 10 ppb or less, and even more preferably 5 ppb or less. The lower limit of the 2-ethyl-6-methylpyrazine content in the pasteurized soy sauce is not particularly limited, and may be below the detection limit, i.e., substantially 0 ppb.

[0025] The pasteurized soy sauce of one embodiment of the present invention is characterized by having a flavor-improving effect, while also having the original flavor of soy sauce due to the inclusion of soy sauce components such as HEMF (4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone). Therefore, the HEMF content in the pasteurized soy sauce is preferably 20 ppm or more, more preferably 30 ppm or more, and even more preferably 40 ppm or more. The upper limit of the HEMF content can be set appropriately depending on the desired original flavor of soy sauce, and is typically around 200 ppm.

[0026] The contents of phenethyl acetate and alcohol in the pasteurized soy sauce of one embodiment of the present invention can be measured by the method described in the Examples below. The contents of 2-ethyl-6-methylpyrazine and HEMF can be measured by the method described in Patent Document 1.

[0027] The method for producing a pasteurized soy sauce according to one embodiment of the present invention is not particularly limited as long as it can produce a pasteurized soy sauce having a predetermined phenethyl acetate content, but production by the hon-jozo method is preferred. In this case, unlike the usual hon-jozo method, the soy sauce moromi obtained by lactic acid fermentation is used for yeast fermentation after removing insoluble solids.

[0028] Specific examples of methods for producing pasteurized soy sauce include a method comprising the steps of obtaining soy sauce moromi mash by a brewing method, removing insoluble solids from the obtained soy sauce moromi mash to obtain a soy sauce moromi broth, fermenting the soy sauce moromi broth with yeast to obtain raw soy sauce, and pasteurizing the obtained raw soy sauce to obtain pasteurized soy sauce. Other specific examples of methods for producing pasteurized soy sauce include a method comprising the steps of obtaining soy sauce moromi mash by a brewing method, removing insoluble solids from the obtained soy sauce moromi mash to obtain a soy sauce moromi broth, pasteurizing the soy sauce moromi broth to obtain a pasteurized soy sauce moromi broth, and fermenting the pasteurized soy sauce moromi broth with yeast to obtain pasteurized soy sauce. Non-limiting examples of each step are described below.

[0029] The process for obtaining soy sauce moromi mash includes a step of inoculating a soy sauce raw material, which is a mixture of steamed and denatured soybeans, roasted and crushed barley, etc., with koji starter, and then aerating the koji at 20°C to 40°C for about 2 to 4 days to obtain soy sauce koji. The soy sauce koji is then placed in brine with a salt concentration of 20% to 30% by mass, and soy sauce lactic acid bacteria is optionally added to the mixture, followed by lactic acid fermentation at 20°C to 40°C for 10 to 200 days with appropriate stirring to obtain soy sauce moromi mash.

[0030] The soy sauce raw material is not particularly limited, but examples thereof include soybeans such as whole soybeans and defatted soybeans, wheat, barley, naked barley, adlay and other barley, wheat gluten, rice, corn and the like.

[0031] The seed koji is not particularly limited as long as it is a koji mold that is usually used in the production of soy sauce. For example, Aspergillus oryzae ( Aspergillus oryzae ), Aspergillus sojae ( A.sojae The soy sauce lactic acid bacteria are not particularly limited as long as they are soy sauce lactic acid bacteria that are normally used in the production of soy sauce. For example, Tetragenococcus halophilus ( Tetragenococcus halophilus ) and other salt-tolerant lactic acid bacteria.

[0032] In the process of obtaining soy sauce moromi mash, if the amount of starchy raw materials such as wheat or rice among the soy sauce raw materials is small, the reducing sugar content will be low, and it may be impossible to obtain soy sauce moromi mash that can be properly fermented with yeast. Therefore, it is preferable that the amount of starchy raw materials such as wheat or rice among the soy sauce raw materials is an amount that allows a soy sauce moromi mash with a high reducing sugar content to be obtained. However, this does not apply when a soy sauce moromi mash with a high reducing sugar content is obtained by adding reducing sugar components, such as glucose, fructose, maltose, sugar, mirin, etc., to the soy sauce moromi mash. In other words, soy sauce koji includes adjusted soy sauce koji obtained by inoculating a protein raw material such as soybean with koji starter to produce koji with a high total nitrogen content, and then adding reducing sugar components to adjust the soy sauce koji. Note that reducing sugar means direct reducing sugar as defined in the Ministry of Agriculture, Forestry and Fisheries Notification "Japanese Agricultural Standards for Soy Sauce."

[0033] The step of obtaining a soy sauce moromi mash may include a step of subjecting the soy sauce moromi mash to a commonly known solid-liquid separation treatment or a solid-liquid separation treatment and sterilization treatment, and removing insoluble solids to an extent that phenethyl acetate is produced by yeast fermentation in the subsequent stage, thereby obtaining a soy sauce moromi mash.

[0034] Examples of solid-liquid separation and sterilization treatments include filtration using a filter material such as diatomaceous earth, membrane filtration using various permeable membranes such as MF membranes and UF membranes, squeeze filtration using a press machine with a filter cloth, and heating treatments in which the temperature is raised to a level at which microorganisms are killed. These can be performed alone or in combination, and each can be repeated once or multiple times. In order to ensure that phenethyl acetate is properly synthesized by yeast fermentation in the subsequent stage, it is preferable that the soy sauce mash has been removed from which most of the soy sauce lactic acid bacteria have been removed, along with the insoluble solids. The content of lactic acid bacteria in the soy sauce mash is not particularly limited, but for example, 1.0 × 10 8 It is preferable that the number of cells is less than 1.0 × 10 7 It is more preferable that the number of cells is less than 1.0 × 10 6Therefore, the soy sauce moromi mash is preferably a mash obtained by removing insoluble solids and soy sauce lactic acid bacteria from soy sauce moromi mash.

[0035] The process for obtaining raw soy sauce includes a process in which the liquid of soy sauce moromi is subjected to yeast fermentation, which is employed in the conventional soy sauce manufacturing method using the honjozo method. As the soy sauce yeast, for example, Zygosaccharomyces ruxii ( Zygosaccharomyces rouxii ), Zygosaccharomyces baili ( Z. bailii ), Candida etquersii ( Candida etchellsii ), Candida verstilis ( C. versatilis ) and other salt-tolerant yeasts.

[0036] Yeast fermentation can be carried out under conditions suitable for the type and amount of soy sauce yeast, for a period until the amount of alcohol (ethanol) produced reaches its maximum. However, if the yeast fermentation period is too long, the amount of phenethyl acetate lost by esterases and the like may be greater than the amount of phenethyl acetate produced by yeast fermentation, resulting in a decrease in the phenethyl acetate content. Therefore, it is preferable to terminate yeast fermentation before the alcohol concentration reaches its maximum, or before the phenethyl acetate content decreases. A specific example of yeast fermentation is soy sauce yeast. Zygosaccharomyces rouxii When using the above, the reaction is carried out at room temperature, preferably at 15° C. to 30° C., for about 5 to 60 days, preferably about 7 to 45 days.

[0037] After the completion of yeast fermentation, the maturation period begins. Yeast fermentation is terminated when the alcohol concentration reaches approximately its maximum value. More specifically, yeast fermentation is preferably terminated when the average alcohol production rate over the most recent 10 days becomes 0.2% (v / v) or less, but a target alcohol concentration may be set in advance. Since the content of phenethyl acetate decreases during the maturation period, maturation is preferably completed at room temperature, preferably 15°C to 30°C, within 30 days, more preferably within 20 days, and even more preferably within 10 days. In the soy sauce production process, the moromi mash after fermentation and maturation is generally pressed to obtain raw soy sauce, which is then stored for a long period in the raw soy sauce state. However, in this production method, regardless of maturation or storage, the maturation storage period after the completion of yeast fermentation is completed within the above-mentioned conditions.

[0038] After the aging process is completed, the pasteurization process begins. Examples of the process for obtaining pasteurized soy sauce include a process in which pasteurization is performed in a conventional method for producing soy sauce using the traditional brewing method. The pasteurization conditions are those that do not reduce the content of phenethyl acetate when the resulting pasteurized soy sauce is stored, i.e., those that inactivate the koji mold-derived esterase. Examples of the pasteurization conditions include a temperature of 70°C to 125°C, preferably 70°C to 90°C, for 1 second to 60 minutes, preferably about 1 minute to 30 minutes. Alternatively, instead of pasteurization, a separate process (enzyme inactivation process) for inactivating the koji mold-derived esterase may be performed. Examples of such a process include a process for removing the koji mold-derived esterase, specifically, a membrane process using a UF membrane. Soy sauce obtained by UF membrane treatment may be referred to as pasteurized soy sauce, as it is a soy sauce obtained by a process equivalent to pasteurization, or as UF membrane-treated soy sauce.

[0039] Since the raw soy sauce before pasteurization is obtained using the liquid of soy sauce moromi from which insoluble solids have been removed in advance, it is a yeast-fermented product with a low solid content, and it may be pasteurized itself. In addition, in order to remove yeast, residues, etc. in the raw soy sauce, solid-liquid separation treatments used in the subsequent stage of yeast fermentation in ordinary soy sauce manufacturing methods, such as squeezing, filtration, and lees removal, may be carried out before or after pasteurization.

[0040] As described in the Examples below, it is highly likely that the esterases that reduce the amount of phenethyl acetate are derived from soy sauce koji. Therefore, the pasteurized soy sauce of one embodiment of the present invention may be obtained by pasteurizing soy sauce moromi mash or a soy sauce moromi mash to inactivate the koji-derived esterase, in addition to pasteurizing raw soy sauce, followed by yeast fermentation. In this case, instead of the step of obtaining raw soy sauce, a step of pasteurizing the soy sauce moromi mash to obtain a pasteurized soy sauce moromi mash and a step of using the pasteurized soy sauce moromi mash to perform yeast fermentation to obtain pasteurized soy sauce are carried out. In this case, since the reduction of phenethyl acetate during the aging period can be suppressed by pasteurizing the soy sauce moromi mash, the aging period (e.g., 10 days to 100 days to 1 year) employed in the conventional brewing method for soy sauce can be used. The pasteurization conditions described above can be applied. In this case, the soy sauce obtained after yeast fermentation preferably contains 30 ppb or more of phenethyl acetate and exhibits a phenethyl acetate reduction rate of 5% or less when aged at 25°C for one week.

[0041] The pasteurized soy sauce of one embodiment of the present invention can be packaged in a container and sealed to form a packaged pasteurized soy sauce. The container is not particularly limited, and examples include packaging containers made of metals such as aluminum, paper, plastics such as PET and PTP, glass, single-layer or laminated film bags, retort pouches, vacuum packs, aluminum containers, plastic containers, bottles, cans, and the like. Packaged pasteurized soy sauce can be sold commercially and independently by itself.

[0042] Specific examples of pasteurized soy sauce according to one embodiment of the present invention include, but are not limited to, the pasteurized soy sauces described in Examples 1 and 2 of Example 1 below. Note that soy sauce produced by the same method as the test solution described in Example 1 of Example 1 has a 2-ethyl-6-methylpyrazine content of 5 ppb or less and a HEMF content of 20 ppm or more.

[0043] The pasteurized soy sauce of one embodiment of the present invention can be used in the same manner as regular pasteurized soy sauce. That is, the pasteurized soy sauce of one embodiment of the present invention can be used alone or in combination with vegetable ingredients, meat, fish, yeast extract, meat extract, fruit juice, spices, chemical seasonings, flavors, and other seasoning ingredients such as dashi, acidulants, amino acids, nucleic acids, organic acids, protein hydrolysates, sugar, sake, mirin, alcohol, thickeners, emulsifiers, and inorganic salts in cooking and processing methods for various ingredients. For example, the pasteurized soy sauce of one embodiment of the present invention can be used in various dishes such as Japanese, Western, and Chinese cuisine. Specifically, it can be used in fried foods, yakiniku (grilled meat), udon, soba, ramen, hamburger steak, meatballs, Chikuzenni (stewed meat and potato stew), teriyaki, curry, stew, hayashi (hashed beef), and meat tofu, but is not limited to these.

[0044] Non-limiting specific examples of the pasteurized soy sauce of one aspect of the present invention include pasteurized soy sauces having the following contents of phenethyl acetate and 2-ethyl-6-methylpyrazine: Phenethyl acetate content: 30 ppb to 20,000 ppb 2-Ethyl-6-methylpyrazine content: 0 ppb to less than 20 ppb

[0045] Non-limiting specific examples of the pasteurized soy sauce of one aspect of the present invention include pasteurized soy sauces having the following contents of phenethyl acetate and HEMF: Phenethyl acetate content: 30 ppb to 20,000 ppb HEMF content: 20 ppm to 200 ppm

[0046] Non-limiting specific examples of the pasteurized soy sauce of one aspect of the present invention include pasteurized soy sauces having the following contents of phenethyl acetate, 2-ethyl-6-methylpyrazine, and HEMF: Phenethyl acetate content: 30 ppb to 20,000 ppb, preferably 30 ppb to 3,000 ppb 2-Ethyl-6-methylpyrazine content: 0 ppb to less than 20 ppb HEMF content: 20 ppm to 200 ppm

[0047] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples, and the present invention can take various forms as long as the object of the present invention can be achieved. [Example]

[0048] Example 1: Evaluation of the formation behavior of phenethyl acetate during yeast fermentation [1-1. Purpose of evaluation] The behavior of phenethyl acetate production during yeast fermentation of liquid-fermented soy sauce was evaluated. Hereinafter, the yeast fermentation method of the present invention will be referred to as liquid fermentation.

[0049] [1-2. Preparation of test solution] Test solutions were prepared by making the following fermented liquid soy sauce.

[0050] A mixture of steamed whole soybeans and cracked roasted wheat in a ratio of 6:4 was inoculated with Aspergillus sojae ( Aspergillus sojae ) was inoculated and koji was produced by the usual method for 43 hours to obtain soy sauce koji.

[0051] 100 parts by mass of the obtained soy sauce koji was added to 116 parts by mass of salt water (salt concentration 25% (w / v)), and then soy sauce lactic acid bacteria ( Tetragenococcus halophilus) was added and subjected to lactic acid fermentation for 20 days at 15°C to 25°C with appropriate stirring according to a conventional method. After the lactic acid fermentation was completed, the soy sauce moromi mash was pressed, and the resulting pressed liquid was filtered through diatomaceous earth and then through a UF membrane to obtain a liquid fermentation base liquid as a soy sauce moromi mash.

[0052] The liquid fermentation liquid was placed in a 250 mL Duran bottle (N=2) and the salt-tolerant soy sauce yeast ( Zygosaccharomyces rouxii ) was inoculated, stoppered, and yeast fermentation was carried out at 25°C for 4 weeks. One test group was pasteurized at 80°C for 30 minutes, while the other test group was not pasteurized. Yeast fermentation was then carried out in the same manner for another 8 weeks. Sampling was carried out every two weeks and stored at -20°C. 12 weeks after yeast fermentation, the alcohol, phenethyl acetate, 2-ethyl-6-methylpyrazine, and HEMF contents in the samples were measured. 2-ethyl-6-methylpyrazine and HEMF were measured according to standard methods.

[0053] [1-3. Measurement method of phenethyl acetate] Aroma compounds in the gas phase were adsorbed onto a fiber by headspace solid-phase microextraction (HS-SPME). The SPME fiber was a divinylbenzene / carboxen / polydimethylsiloxane (DVB / CAR / PDMS) fiber (75 mm, DVB / CAR / PDMS, fused silica, 24Ga; Merck). The equilibration conditions were 40°C for 5 minutes, and the adsorption conditions were 40°C for 20 minutes.

[0054] The collected aroma components were analyzed using an autosampler "AOC5000" (Shimadzu Corporation) by introducing them into a GC-MS "GCMS QP-2010 Ultra" (Shimadzu Corporation). The analysis was performed with n=4. The GC / MS conditions were as follows: Measurement mode: Scan Column: DB WAX 60 x 0.25 mm, id 0.25 μm (Agilent) Carrier gas: Helium Linear flow rate: 40 cm / min Oven temperature: 40°C (hold for 3 minutes) → 5°C / min → 110°C → 10°C / min → 240°C (hold for 5 minutes) Ion source temperature: 240°C Transfer line temperature: 240°C Ionization mode: EI Mass range: 30 m / z ~ 250 m / z Measurement time: 2 minutes ~ 35 minutes Target ion of phenethyl acetate: 104 m / z As described above, the peak area of phenethyl acetate was calculated by GC-MS. The correction of the peak area was performed using LOWESS smoothing based on the results of analyzing a quality control obtained by mixing equal amounts of the samples to be analyzed.

[0055] [1-4. Quantitative method for alcohol] Alcohol (ethanol) was measured by GC-FID under the following conditions according to a conventional method.

[0056] <GC-FID analysis conditions> Measuring device: GC-2014AF (manufactured by Shimadzu Corporation) Column: porapack q (80-100 mesh) (manufactured by GL Sciences Inc.) Inlet temperature: 230°C Temperature condition: Hold at 155°C (for 7 minutes) Carrier gas: Nitrogen Linear flow rate: 20 mL / min Detector temperature: 250°C

[0057] [1-5. Evaluation results] The measurement results of phenethyl acetate for each sample are shown in Fig. 1. As shown in Fig. 1, the amount of phenethyl acetate increased until 4 weeks after the start of fermentation. The content of phenethyl acetate 4 weeks later was 229 ppb, the content of 2-ethyl-6-methylpyrazine was 1.9 ppb, the content of HEMF was 84 ppm, and the content of alcohol was 2.1%.

[0058] After that, the phenethyl acetate content in the non-pasteurized test group decreased significantly. On the other hand, the decrease in the phenethyl acetate content in the pasteurized test group was suppressed, but it did not increase either. The final phenethyl acetate content in the non-pasteurized test group was 21.5 ppb.

[0059] From the above results, it was found that in yeast fermentation using a liquid fermentation stock, the phenethyl acetate content increases for 4 weeks after the start of fermentation, that the amount of phenethyl acetate reduced by the decomposing enzyme exceeds the amount of phenethyl acetate produced by yeast fermentation after 4 weeks, and that the phenethyl acetate content can be maintained by pasteurizing the stock 4 weeks after the start of fermentation. Furthermore, it was found that a yeast fermentation period of about 4 weeks is preferable to obtain soy sauce containing a high concentration of phenethyl acetate.

[0060] Example 2: Evaluation of suppression of phenethyl acetate reduction by pasteurization timing [2-1. Purpose of evaluation] The liquid fermentation base liquid after lactic acid fermentation was pasteurized to inactivate esterases derived from soy sauce koji and lactic acid bacteria, and then yeast fermentation was carried out, and the suppression of the decrease in phenethyl acetate was evaluated.

[0061] [2-2. Evaluation Method] A liquid fermentation base liquid was obtained in the same manner as in 1-2 above.

[0062] The resulting liquid fermentation base liquid was pasteurized at 80°C for 30 minutes, then placed in a 200mL Duran bottle and fermented with salt-tolerant soy sauce yeast ( Zygosaccharomyces rouxii ) was seeded, plugged, and yeast fermentation was carried out at 25°C for 4 weeks (pasteurized group). The untreated group was subjected to yeast fermentation in the same manner except for not being pasteurized. The phenethyl acetate content of the pasteurized and untreated samples was measured (N=4 for the analysis).

[0063] [2-3. Evaluation Results] The measurement results of phenethyl acetate in each sample are shown in Figure 2.

[0064] As shown in Figure 2, the amount of phenethyl acetate in the pasteurized group was more than 10 times higher than that in the untreated group. This result indicates that the esterases in the liquid fermented soy sauce are likely derived from the soy sauce koji. Therefore, it was found that the amount of phenethyl acetate increases by inactivating the esterases either before or after the yeast fermentation of the liquid fermentation base liquid.

[0065] Example 3: Evaluation of the decomposition activity of koji-derived enzymes for phenethyl acetate [3-1. Purpose of evaluation] The decomposition activity of phenethyl acetate in the liquid fermentation stock was evaluated.

[0066] [3-2. Evaluation Method] A phenethyl acetate stock solution (1 g / 100 ml) was prepared by adding 1 g of 98% pure phenethyl acetate (Sigma-Aldrich) to a 100 ml volumetric flask and diluting it with 95% ethanol. The phenethyl acetate stock solution was then diluted with water to prepare each test soy sauce, so that the amount of phenethyl acetate added to each test soy sauce (described below) was standardized to 100 μl, and the phenethyl acetate content in each test soy sauce reached the specified concentration.

[0067] A phenethyl acetate solution was added to the liquid fermentation base liquid so that the phenethyl acetate content was 30 ppb. As the liquid fermentation base liquid, Aspergillus sojae ( Aspergillus sojae Two strains (strain A and strain B) with different phenotypes were used.

[0068] Each liquid fermentation base liquid was divided into two, one of which was pasteurized at 80°C for 30 minutes and then incubated at 25°C for 24 hours (pasteurized group), and the other was not pasteurized and was incubated at 25°C for 24 hours (untreated group).

[0069] The phenethyl acetate content after incubation was measured for the A strain burned group, the A strain untreated group, the B strain burned group, and the B strain untreated group.

[0070] [3-3. Evaluation Results] Table 1 shows the measurement results of phenethyl acetate for each test group and the decomposition rate (reduction rate) calculated based on the phenethyl acetate content (30 ppb) before incubation.

[0071] [Table 1]

[0072] As shown in Table 1, the decomposition activity of phenethyl acetate differed between strains A and B, but both strains were found to decompose more than 40% of phenethyl acetate. However, it was found that the decomposition of phenethyl acetate could be suppressed in both strains by heating.

[0073] These results show that by pasteurizing the yeast fermentation base liquid, a liquid fermentation base liquid and pasteurized soy sauce can be obtained in which the reduction rate of phenethyl acetate when stored at 25°C for 24 hours is 30% or less.

[0074] Example 4 Evaluation of decomposition activity of phenethyl acetate during aging [4-1. Purpose of evaluation] The decomposition activity of phenethyl acetate during the aging period was evaluated.

[0075] [4-2. Evaluation Method] The liquid fermentation liquid was placed in a 250 mL Duran bottle (N=2) and the salt-tolerant soy sauce yeast ( Zygosaccharomyces rouxii ) was seeded, the mixture was stoppered, and yeast fermentation was carried out for 4 weeks at 25°C. Based on the amounts of alcohol and phenethyl acetate produced at this point, the yeast fermentation period was considered to have ended, and the subsequent period was considered to be the maturation period, and the amount of phenethyl acetate after the start of the maturation period was measured.

[0076] [4-3. Evaluation Results] The results of measuring phenethyl acetate after a certain aging period are shown in Table 2.

[0077] [Table 2]

[0078] As shown in Table 2, after the start of the aging period, the decomposition activity of phenethyl acetate in soy sauce tends to decrease, but the rate of decrease per week does not fall below 5%. Furthermore, as shown in Figure 1, the amount of phenethyl acetate in soy sauce does not decrease after pasteurization.

[0079] These results indicate that pasteurized soy sauce can be obtained in which the reduction rate of phenethyl acetate is 5% or less when aged at 25°C for one week. [Example]

[0080] Example 1: Evaluation of the effect on the flavor of soy sauce [1-1. Preparation of test soy sauce] A phenethyl acetate stock solution (1 g / 100 ml) was prepared by adding 1 g of 98% pure phenethyl acetate (Sigma-Aldrich) to a 100 ml volumetric flask and diluting it with 95% ethanol. The phenethyl acetate stock solution was then diluted with water to prepare each test soy sauce, so that the amount of phenethyl acetate added to each test soy sauce (described below) was standardized to 100 μl, and the phenethyl acetate content in each test soy sauce reached the specified concentration.

[0081] Soy sauce and each phenethyl acetate solution were mixed and dissolved by stirring to prepare 100 ml of each test soy sauce so that the phenethyl acetate content was 0 ppb (no additives), 30 ppb, or 50 ppb. The soy sauce used was "Kikkoman Special Whole Soybean Soy Sauce" (manufactured by Kikkoman Corporation), in which no phenethyl acetate was detected.

[0082] The prepared test soy sauce was subjected to the following tests 1 to 3. That is, in test 1, the prepared test soy sauce was heated to 80°C in a hot water bath, then rapidly cooled in ice and maintained at approximately 25°C. In test 2, it was stored in an incubator at 60°C for 2 days. In test 3, the prepared test soy sauce was stored in an incubator at 5°C for 2 days.

[0083] [1-2. Sensory evaluation method] For the test soy sauces of each test group, five panelists (A to E) who excelled in distinguishing the flavor of soy sauce were asked to take a spoonful of the test soy sauce and eat it at room temperature of approximately 25°C, and evaluate the intensity of the heat-deteriorated odor, soy sauce aroma, and astringent taste that emanated from the mouth to the nose when consuming the soy sauce.

[0084] "Heat-deteriorated odor" was the unpleasant and stuffy odor (a smell that makes your nose feel steamy) that is unique to soy sauce that has been heated at a high temperature and that is felt when you put it in your mouth. "Soy sauce aroma" was the refreshing and fruity aroma that is inherent to soy sauce that is felt when you put it in your mouth with soy sauce that has not been subjected to heat treatment (i.e., commercially available soy sauce). "Astringent taste" was the astringent flavor that remains in the mouth after eating.

[0085] In the sensory evaluation, the test soy sauce without added phenethyl acetate was used as the evaluation standard ("0"), and the strength of each test soy sauce's evaluation item was rated on the following nine-point scale. Prior to conducting the sensory test, the panel discussed the flavor of the soy sauce and underwent evaluation training. Specifically, the panel discussed and refined the flavor characteristics of the soy sauce so that each panelist had a common understanding. Furthermore, to ensure the validity of the sensory test, the panel trained in evaluation using several test soy sauces, and the reproducibility of the evaluations by each panelist was confirmed. After these were performed, the panel evaluated the flavor of each test soy sauce. -4: Feels very weak compared to the evaluation criteria -3: Feels quite weak compared to the evaluation criteria -2: Feels weak compared to the evaluation criteria -1: Feels a little weak compared to the evaluation criteria 0: Feels the same as the evaluation criteria 1: Compared to the evaluation criteria, it feels somewhat strong 2: Compared to the evaluation criteria, I feel strongly 3: Compared to the evaluation criteria, I feel it is quite strong. 4: Compared to the evaluation criteria, I feel very strongly

[0086] [1-3. Sensory evaluation results] For each test soy sauce, sensory evaluation was carried out on the evaluation items of "heat-deteriorated odor," "soy sauce aroma," and "harshness," and the results are shown in Tables 3A to 3C.

[0087] [Table 3A]

[0088] [Table 3B]

[0089] [Table 3C]

[0090] As shown in Tables 3A to 3C, in Tests 1 and 2 in which the test soy sauces were subjected to heat treatment, the test soy sauces containing phenethyl acetate had a stronger soy sauce aroma and reduced heat deterioration odor and harsh taste compared to the test soy sauces containing no phenethyl acetate, which were the evaluation criteria.

[0091] In addition, in Test 3, in which the test soy sauces were stored without being subjected to heat treatment, the test soy sauces containing phenethyl acetate had a slightly stronger soy sauce aroma and a reduced harshness compared to the test soy sauces containing no phenethyl acetate. In this case, no heat-deteriorated odor was detected in any of the test soy sauces.

[0092] From the above results, it was found that phenethyl acetate has the effect of improving the flavor of soy sauce and the effect of suppressing the deterioration of the flavor of soy sauce.

[0093] Example 2: Evaluation of the effect of fruit juice on the flavor of ponzu sauce (1) [2-1. Preparation of test ponzu sauce] A 100 ml volumetric flask was charged with 1 g of 98% pure phenethyl acetate (Sigma-Aldrich) and diluted with 95% ethanol to prepare a phenethyl acetate stock solution (1 g / 100 ml). The phenethyl acetate stock solution was then diluted with water to prepare each test ponzu sauce, with the amount of phenethyl acetate added to each sauce adjusted to a standard 100 μl, and the phenethyl acetate content of each test ponzu sauce adjusted to the specified concentration.

[0094] Soy sauce, yuzu juice, vinegar, sugar, glutamic acid, water, and each phenethyl acetate solution were placed in stainless steel tubes in the amounts shown in Table 4 below and stirred at approximately 40°C to prepare 100 ml of each test ponzu sauce. The soy sauce used was "Kikkoman Special Whole Soybean Soy Sauce" (manufactured by Kikkoman Corporation), in which no phenethyl acetate was detected. The yuzu juice used was a non-heated, bottled product of straight juice. Regarding the phenethyl acetate concentration, 10 ppb means that 1,000 mg of phenethyl acetate is present in 100 ml of test ponzu sauce.

[0095] The prepared test ponzu sauces were designated as test ponzu sauces 1-1 to 8-1 before heating. Test ponzu sauces 1-1 to 8-1 were heated to 80°C in a hot water bath, then rapidly cooled in ice and maintained at approximately 25°C, designated as test ponzu sauces 1-2 to 8-2 after heating.

[0096] [Table 4]

[0097] [2-2. Sensory evaluation method] For test ponzu 1-1 to 8-1 and test ponzu 1-2 to 8-2, panelists (three people, A to C) who are skilled in distinguishing the flavor and aroma of fruit juice were asked to take a spoonful of test ponzu, eat it, and smell it at room temperature of approximately 25°C.

[0098] The evaluation items were "fruit juice flavor," "acidity," and "off-flavor" when tasting, and "fresh citrus aroma" when sniffing.

[0099] "Fruit juice flavor" was the fruit juice flavor felt when the test ponzu was eaten and put in the mouth. "Sourness" was the sour taste felt on the tongue when the test ponzu was eaten and put in the mouth. "Off-flavor" was either the astringency or bitterness (peeliness) felt on the tongue when the test ponzu was eaten and put in the mouth. "Fresh citrus aroma" was the grassy, ​​sour aroma that is produced when citrus fruits are squeezed, felt relatively early on by the nose alone without putting the test ponzu in the mouth.

[0100] In the sensory evaluation, the heated test ponzu 1-2 without the addition of phenethyl acetate was used as the evaluation standard ("0"), and the strength of each test ponzu was evaluated on the following nine-point scale. Prior to conducting the sensory evaluation, the panel discussed and trained on the flavor and aroma of the fruit juice. Specifically, the panel discussed and refined the characteristics of the flavor and aroma of the fruit juice so that each panelist had a common understanding. To ensure the validity of the sensory evaluation, the panel trained on evaluation using several test ponzus, and the reproducibility of the evaluations by each panelist was confirmed. After these evaluations, the panel evaluated the flavor and aroma of each test ponzu. -4: Feels very weak compared to the evaluation criteria -3: Feels quite weak compared to the evaluation criteria -2: Feels weak compared to the evaluation criteria -1: Feels a little weak compared to the evaluation criteria 0: Feels the same as the evaluation criteria 1: Compared to the evaluation criteria, it feels somewhat strong 2: Compared to the evaluation criteria, I feel strongly 3: Compared to the evaluation criteria, I feel it is quite strong. 4: Compared to the evaluation criteria, I feel very strongly

[0101] [2-3. Sensory evaluation results] The results of sensory evaluation of each test ponzu for the evaluation items "fruit juice flavor," "off-flavor," and "fresh citrus aroma" are shown in Tables 5A to 5C. Regarding the evaluation item "sourness," no significant differences were observed among the test ponzu.

[0102] [Table 5A]

[0103] [Table 5B]

[0104] [Table 5C]

[0105] As shown in Tables 5A to 5C, the heated test ponzu 2-2 to 7-2 containing phenethyl acetate had a stronger fruit juice flavor and fresh citrus aroma than the heated test ponzu 1-2 without phenethyl acetate, which was the evaluation standard, and the unpleasant flavor was reduced. Furthermore, a comparison of test ponzu 1-1 and test ponzu 1-2 without phenethyl acetate revealed that heating impaired the desirable flavor. Taking these results together, it was found that adding phenethyl acetate to ponzu can suppress the deterioration of flavor caused by heating fruit juice.

[0106] Furthermore, the test results for test ponzu 1-1 to 7-1 before heating showed that the addition of a larger amount of phenethyl acetate improved the flavor compared to those without phenethyl acetate. However, test ponzu 8-1 and 8-2, which contained 5,000 ppb of phenethyl acetate, had an overall floral aroma, possibly due to the rose scent of phenethyl acetate, making it impossible to conduct a sensory evaluation. Furthermore, when test ponzu 8-2 was poured over boiled tofu and eaten, the floral aroma was still noticeable, creating an unpleasant feeling, and it was found to be unsuitable as a ponzu.

[0107] From the above results, it was found that phenethyl acetate has the effect of improving the flavor of fruit juice and the effect of suppressing the deterioration of flavor due to heating of fruit juice.

[0108] Example 3: Evaluation of the effect of fruit juice on the flavor of ponzu sauce (2) [3-1. Preparation of test ponzu sauce] Test ponzu sauces 9-1 to 13-1 and 9-2 to 13-2 were obtained after heating in the same manner as in Example 2, except that the blending amounts shown in Table 6 below were used. Each test ponzu sauce was filled into a 100 ml transparent bottle and stored for 15 days at 5°C for test ponzu sauces 9-1 to 13-1 and at 40°C for test ponzu sauces 9-2 to 13-2. The pH of each test ponzu sauce was measured, and all of the pH values ​​were within the range of 3.87 to 3.90.

[0109] [Table 6]

[0110] [3-2. Sensory evaluation method] Test Ponzu 9-1 to 13-1 and Test Ponzu 9-2 to 13-2 were subjected to sensory evaluation for "fruit juice flavor," "acidity," "off-flavor," and "fresh citrus aroma" in the same manner as in Example 2. However, the evaluation criteria were those for Test Ponzu 9-1, which was a product stored at 5°C and did not contain phenethyl acetate.

[0111] [3-3. Sensory evaluation results] The results of sensory evaluation of each test ponzu for the evaluation items "fruit juice flavor," "off-flavor," and "fresh citrus aroma" are shown in Tables 7A to 7C. Regarding the evaluation item "sourness," no significant differences were observed among the test ponzu.

[0112] [Table 7A]

[0113] [Table 7B]

[0114] [Table 7C]

[0115] As shown in Tables 7A to 7C, Test Ponzu 9-2, which did not contain phenethyl acetate and was stored at 40°C, had a weakly favorable flavor ("fruit juice flavor," "fresh citrus aroma") and a strong unfavorable flavor ("off-flavor"). However, as shown by the results of Test Ponzu 10-2 to 13-2, the favorable flavor tended to be stronger and the unfavorable flavor reduced depending on the amount of phenethyl acetate added. A similar trend was also observed in the test results using Test Ponzu stored at 5°C.

[0116] From the above results, it was found that ponzu sauce containing phenethyl acetate can be stored while retaining a desirable fruit juice flavor regardless of temperature conditions. [Industrial Applicability]

[0117] The pasteurized soy sauce of one embodiment of the present invention can improve the flavor of ingredients and cooked foods, and furthermore, since it can be produced using the traditional brewing method, it can be produced and used industrially along with or in place of commercially available soy sauce.

[0118] This application claims priority from Japanese Patent Application No. 2020-056774, filed March 26, 2020, the entire disclosure of which is incorporated herein by reference.

Claims

1. A pasteurized soy sauce containing phenethyl acetate at 30 ppb or more and less than 20,000 ppb and 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone at 20 ppm or more, wherein the reduction rate of phenethyl acetate when aged at 25°C for one week is 5% or less.

2. The pasteurized soy sauce according to claim 1, containing 100 ppb or more and less than 20,000 ppb of phenethyl acetate.

3. The pasteurized soy sauce according to claim 1 or 2, wherein the soy sauce is brewed soy sauce.

4. a step of subjecting the soy sauce koji to lactic acid fermentation using soy sauce lactic acid bacteria to obtain soy sauce moromi mash, and subjecting the soy sauce moromi mash to solid-liquid separation treatment to obtain a soy sauce moromi mash; a step of subjecting the soy sauce moromi broth to yeast fermentation with soy sauce yeast to obtain a phenethyl acetate-containing soy sauce; A step of pasteurizing the phenethyl acetate-containing soy sauce before 30 days have passed since the end of yeast fermentation; A method for producing a phenethyl acetate-containing soy sauce containing 30 ppb or more and less than 20,000 ppb of phenethyl acetate.

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