Unfiltered vinegar and method for producing unfiltered vinegar

Abstract

To provide an unfiltered vinegar containing a large number of bacterial cells of acetic acid bacteria and giving a fermentation feeling derived from the acetic acid bacteria, and to provide a method for producing the same.SOLUTION: There is provided an unfiltered vinegar having an acidity of 4% or more and 9% or less, containing acetic acid bacteria. The main acetic acid bacteria which account for 90% or more of bacterial cells contained in unfiltered vinegar are acetic acid bacteria of one kind selected from the genera Gluconacetobacter, Acetobacter, Gluconobacter, Komagataeibacter, and Novacetimonas. The number of bacterial cells of the acetic acid bacteria is 1.0×108 cells / mL or more, and the dry weight of the solids is 5% (w / v) or more and 18% (w / v) or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to cloudy vinegar containing acetic acid bacteria and a method for producing the same. [Background technology]

[0002] Vinegar is produced by acetic acid fermentation by acetic bacteria in a medium containing ethanol, etc. In general vinegar, acetic bacteria cause turbidity and are therefore removed by filtration, etc. On the other hand, in recent years, acetic bacteria have been found to have functional properties such as aldehyde oxidation and immunostimulatory activity, and cloudy vinegar containing acetic acid bacteria cells has attracted attention.

[0003] For example, Patent Document 1 discloses an acetic acid bacteria culture solution containing a specific acetic acid bacteria as an acetic acid bacteria culture solution with efficiently enhanced aldehyde oxidizing ability, in which the turbidity at a wavelength of 660 nm (OD660 nm) of the acetic acid bacteria culture solution is 1 to 10, and the aldehyde dehydrogenase activity per 15 mL of the acetic acid bacteria culture solution is 4 to 60. Patent Document 2 discloses vinegar containing fermented cellulose and acetic acid, and further containing acetic acid bacteria cells. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-195807 A [Patent Document 2] JP 2020-210 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, from the viewpoint of functionality, etc., increasing the number of acetic acid bacteria in cloudy vinegar increases the unpleasant taste and reduces the flavor.

[0006] In view of the above circumstances, an object of the present invention is to provide a cloudy vinegar that contains a large amount of acetic acid bacteria cells and has a fermented flavor derived from the acetic acid bacteria, and a method for producing the same. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to achieve the above-mentioned object. As a result, they found that increasing the number of acetic acid bacteria cells increases the unpleasant taste, but under certain conditions, the fragrant and rich fermented taste derived from the acetic acid bacteria can be felt. The present inventors further investigated conditions under which a fermented taste can be obtained stably, and found that the content of acetic acid bacteria is increased to 1.0 x 10 cell count. 8 / mL or more and with the dry weight of the solids adjusted to between 5% (w / v) and 18% (w / v), it was found possible to obtain a cloudy vinegar that contains a large amount of acetic acid bacteria cells while still having a fragrant, rich fermented flavor derived from the acetic acid bacteria, and this led to the completion of the present invention.

[0008] That is, the present invention provides (1) Cloudy vinegar containing acetic acid bacteria and having an acidity of 4% to 9%. The main acetic acid bacteria, which account for more than 90% of the bacterial cells contained in the cloudy vinegar, are one type of acetic acid bacteria selected from the genera Gluconoacetobacter, Acetobacter, Gluconobacter, Komagataebacter, and Nobuacetimonas. The number of acetic acid bacteria is 1.0 × 10 8 / mL or more, The dry weight of solids is between 5% (w / v) and 18% (w / v). Cloudy vinegar, characterized by (2) Also contains fruit juice (1) Cloudy vinegar as described above, (3) The wet weight of the acetic acid bacteria is less than 1% (w / v). (1) or (2) (4) A method for producing cloudy vinegar containing acetic acid bacteria and having an acidity of 4% to 9% The method includes a step of acetic acid fermentation in a medium containing the acetic acid bacteria that has been previously grown. How to make cloudy vinegar, (5) The medium contains 1×10 7 The present invention is characterized by containing more than 1000 / mL of (4) A method for producing cloudy vinegar according to the present invention; (6) In the acetic acid fermentation step, an acetic acid bacteria-containing additive containing the grown acetic acid bacteria is added to a medium containing ethanol to carry out acetic acid fermentation. The method for producing cloudy vinegar according to (4) or (5), (7) The method does not include a step of filtering the medium after the acetic acid fermentation step. The method for producing cloudy vinegar according to any one of (4) to (6), (4)' A method for producing cloudy vinegar containing acetic acid bacteria and having an acidity of 4% to 9%: The method includes the step of carrying out acetic acid fermentation in a medium containing the acetic acid bacteria that have been grown in advance, The main acetic acid bacteria, which account for more than 90% of the bacterial cells contained in the cloudy vinegar, are one type of acetic acid bacteria selected from the genera Gluconoacetobacter, Acetobacter, Gluconobacter, Komagataebacter, and Nobuacetimonas. The number of acetic acid bacteria is 1.0 × 10 8 / mL or more, The dry weight of solids is between 5% (w / v) and 18% (w / v). A method for producing cloudy vinegar, (5)' The medium contains 1 x 10 7 The present invention is characterized by containing more than 1000 / mL of (4)' The method for producing cloudy vinegar according to the present invention (6)' In the acetic acid fermentation step, an acetic acid bacteria-containing additive containing the grown acetic acid bacteria is added to a medium containing ethanol to carry out acetic acid fermentation. (4)' or (5)', the method for producing cloudy vinegar, (7)' The method does not include a step of filtering the medium after the acetic acid fermentation step. A method for producing cloudy vinegar according to any one of (4)' to (6)', It is. Effect of the Invention

[0009] As described above, according to the present invention, it is possible to provide cloudy vinegar that contains a large amount of acetic acid bacteria cells and has a fermented flavor derived from acetic acid bacteria, and a method for producing the same. [Brief description of the drawings]

[0010] [Figure 1] This is an image of cloudy vinegar according to an embodiment (Example 1) of the present invention, magnified 600 times. [Diagram 2] 1 is an image of cloudy vinegar according to a comparative example (Comparative Example 3) of the present invention, magnified 600 times. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below.

[0012] <Features of the present invention> The present invention relates to a cloudy vinegar containing acetic acid bacteria and having an acidity of 4% or more, the cloudy vinegar containing a predetermined main acetic acid bacteria, and the number of cells of the acetic acid bacteria is 1.0×10 8 / mL or more, and the dry weight of the solid content is 5% (w / v) to 18% (w / v). This makes it possible to provide a cloudy vinegar that contains a large amount of acetic acid bacteria cells, yet has a rich fermented taste derived from the acetic acid bacteria and suppresses unpleasant flavors. In the present invention, the "fermented taste" refers to the fragrant, unique flavor emanating from the acetic acid bacteria cells after fermentation and the culture medium containing the acetic acid bacteria cells, other than the aroma derived from raw materials such as fruit juice and grains.

[0013] <Nigori vinegar> In the present invention, the term "cloudy vinegar" refers to vinegar that is turbid. In general vinegar, the acetic acid bacteria are removed by a process such as filtration after acetic acid fermentation by acetic acid bacteria, but the cloudy vinegar of the present invention has cloudiness due to the bacteria without removing the acetic acid bacteria. The cloudy components in the cloudy vinegar of the present invention may contain other bacteria such as yeast and fruit fibers in addition to the bacteria of the acetic acid bacteria. In addition, the cloudy vinegar of the present invention includes vinegar in which a sediment has settled at the bottom of the container and becomes cloudy when stirred. In addition, the vinegar in the present invention refers to a seasoning containing water and acetic acid as the main components, and examples of such vinegar include rice vinegar, black vinegar, five-grain vinegar, wine vinegar, apple vinegar, tomato vinegar, etc. The cloudy vinegar of the present invention is preferably brewed vinegar because it has a fermented feel derived from acetic acid bacteria. In addition, as described below, it is preferable that the cloudy vinegar of the present invention is not a simple mixture of multiple different brewed vinegars produced in different acetic acid fermentation processes, but is produced through a single acetic acid fermentation process.

[0014] <Acidity> The cloudy vinegar of the present invention has an acidity of 4% or more and 9% or less. The acidity in the present invention refers to the "acidity" specified in the Japanese Agricultural Standards for brewed vinegar, and can be calculated by the neutralization titration method described below. By making the acidity of the cloudy vinegar of the present invention 4% or more, the requirements for the acidity of brewed vinegar specified in the Japanese Agricultural Standards can be met. Furthermore, by making the acidity of the cloudy vinegar of the present invention 9% or less, the fermentation sensation derived from acetic acid bacteria can be more reliably felt. Furthermore, the cloudy vinegar of the present invention preferably has an acidity of 6% or less, since the fermentation sensation derived from acetic acid bacteria is more strongly felt.

[0015] <Method of measuring acidity> First, take 10 g of the cloudy vinegar as a sample and dilute it 10 times with ion-exchanged water. Add 2 drops of 0.1% phenolphthalein solution as an indicator to the diluted solution (100 g), and neutralize it with a 0.1 mol / L sodium hydroxide solution of known strength. Calculate the acidity of the sample using the following formula. Acidity of sample (%) = {(60.05 x 0.1 x F x V) x 100} / {amount of sample taken (10 g) x 1000} 60.05: Molecular weight of acetic acid 0.1: Molar concentration of sodium hydroxide solution (mol / L) F: Potency of 0.1 mol / L sodium hydroxide solution V: Titration volume of 0.1 mol / L sodium hydroxide solution (mL)

[0016] <Acetic acid bacteria> Acetic acid bacteria is a general term for microorganisms that grow using sugars and sugar alcohols and oxidize ethanol to produce acetic acid. In the present invention, the main acetic acid bacteria that account for 90% of the bacterial cells contained in the cloudy vinegar are typical acetic acid bacteria used in the production of brewed vinegar, specifically, one type of acetic acid bacteria selected from the genus Gluconacetobacter, Acetobacter, Gluconobacter, Komagataeibacter, and Novacetimonas. Furthermore, in the present invention, since a rich fermented feeling derived from acetic acid bacteria is easily obtained, the main acetic acid bacteria is preferably one type selected from Gluconacetobacter hansenii, Gluconacetobacter liquefaciens, Komagataeibacter maltaceti, and Komagataeibacter medellinensis, and particularly preferably Gluconacetobacter hansenii.

[0017] <Acetate bacteria cell count> In the present invention, the number of acetic acid bacteria contained in the cloudy vinegar is set to 1.0 × 10 from the viewpoint of enhancing the fermented feeling derived from the acetic acid bacteria. 8 In the present invention, the "cell count of acetic acid bacteria" refers to the total cell count of acetic acid bacteria contained in the cloudy vinegar. In addition, from the viewpoint of further enhancing the fermented feeling derived from acetic acid bacteria, the cell count of the acetic acid bacteria is 2.0 × 10 8 The cell count should be 4.0×10 8 The upper limit of the number of acetic acid bacteria is not particularly limited, but from the viewpoint of obtaining a good fermented taste with suppressed unpleasant flavors, it is preferably 5.0 × 10 10The number of cells / mL or less is preferably 2.0×10 10 The cell count is preferably equal to or less than 1 / mL. This cell count is the total number of live and dead cells. In the present invention, by using the cell count itself, rather than turbidity, as an index of the cell count of acetic acid bacteria, the cell count of acetic acid bacteria excluding impurities can be more accurately indicated. The cell count of acetic acid bacteria can be measured by the following method.

[0018] <How to calculate the number of acetic acid bacteria> (1) Dilute the sample so that each square of the hemacytometer contains 5 to 10 bacterial cells. When diluting, it is recommended to use saline, phosphate buffered saline, or pure water. (2) The diluted sample is injected into a Thoma hemocyte plate. (3) Allow to stand for several minutes to several tens of minutes to allow the bacteria to settle. (4) Count the number of bacteria in the squares by observing under a microscope. For chains of bacteria, count the number of individual acetic acid bacteria that make up the chain. Also, only count those acetic acid bacteria whose bodies still retain their original shape, excluding crushed bodies, etc. Furthermore, when multiple bacteria are mixed, only count those whose shapes match the characteristics of acetic acid bacteria described below. (5) To minimize variation in each square, count approximately 80 to 100 squares and calculate the average number of bacteria per square. (6) Calculate the number of bacteria per mL using the following formula. Number of acetic acid bacteria (units / 1mL) = (average number of bacteria per square / volume of one square) x dilution ratio

[0019] [Body shape of acetic acid bacteria] In the production of brewed vinegar, acetic acid fermentation is performed using acetic acid bacteria, so that the elongated rod-shaped bacteria are acetic acid bacteria and can be distinguished from round-shaped bacteria such as yeast (see Figures 1 and 2 described later). In addition, the size of acetic acid bacteria is 1 to 5 μm, which is smaller than the bacteria such as yeast. Thus, in the counting of the number of bacteria in (3) above, the acetic acid bacteria bacteria can be distinguished from other bacteria and the like that are mixed in by visual inspection or image analysis. In addition, examples of rod-shaped bacteria that can grow in vinegar include lactic acid bacteria and Bacillus subtilis, and when these are mixed in, lactic acid bacteria (Lactobacillus genus) and Bacillus subtilis (Bacillus genus) are gram-positive bacteria, and can be distinguished from gram-negative acetic acid bacteria by gram staining. Furthermore, when multiple acetic acid bacteria are mixed, the proportion of each type of acetic acid bacteria may be calculated by genetic analysis.

[0020] <Dry weight of solids> In the present invention, the dry weight of the solid content of the cloudy vinegar is 5% (w / v) or more and 18% (w / v) or less. 8 By adjusting the dry weight of the solid content to a range of 5% (w / v) to 18% (w / v) while containing many bacteria at a concentration of 5 or more bacteria / mL, it is possible to realize a cloudy vinegar that has a fermented taste derived from acetic acid bacteria while suppressing unpleasant flavors. The lower limit of the dry weight of the solid content is preferably 7% (w / v) or more, and more preferably 9% (w / v) or more, from the viewpoint of ensuring a sufficient number of bacteria to obtain a fermented taste. The upper limit of the dry weight of the solid content is preferably 16% (w / v) or less, and more preferably 15% (w / v) or less, from the viewpoint of more effectively suppressing unpleasant flavors.

[0021] <Method for measuring dry weight of solids> Take 1 mL of the cloudy vinegar as a sample, evaporate this sample to dryness in a hot water bath, and then dry it by placing it in a dry heat thermostatic chamber at 105°C for 2 hours and 30 minutes. After cooling the dried sample in a desiccator for 30 to 60 minutes, measure its weight and calculate the dry weight of the solid content using the following formula. Dry weight of solids (% (w / v)) = weight of sample after drying (g) / volume of sample before drying (mL) × 100 However, if salt is included, the dry weight of the solids is calculated by subtracting the weight of salt from the dry weight. The weight of salt can be measured by the Mohr method or other methods.

[0022] <Fruit juice> The cloudy vinegar of the present invention may further contain fruit juice in order to provide a cloudy vinegar with a pleasant taste. The fruit juice is not particularly limited, but examples thereof include apple juice, blueberry juice, lemon juice, mandarin orange juice, grape juice, pomegranate juice, persimmon juice, plum juice, strawberry juice, tomato juice, etc., and one or more of these may be used. The fruit juice may be used as a nutrient source for the culture medium of acetic acid bacteria, but may also be added after fermentation.

[0023] <Wet weight of acetic acid bacteria> The cloudy vinegar of the present invention is characterized by having a large number of acetic acid bacteria cells, while containing few components such as fermented cellulose and other impurities. Therefore, the cells are less likely to swell with water, and the wet weight is easily kept low. Therefore, in the cloudy vinegar of the present invention, the wet weight of the acetic acid bacteria cells is preferably less than 1 (w / v)%, and more preferably 0.7 (w / v)% or less. In the present invention, the "wet weight of the acetic acid bacteria cells" refers to the wet weight of the entire acetic acid bacteria contained in the cloudy vinegar. This wet weight is the weight of the precipitate obtained by removing the supernatant after centrifugation (6000G, 5 min).

[0024] <Other ingredients> In addition to the above-mentioned components, the cloudy vinegar of the present invention can contain various components that are normally used in vinegar, as long as they do not impair the effects of the present invention. Examples of other components include amino acids, salt, sweeteners, thickeners, etc.

[0025] <Effects of the cloudy vinegar of the present invention> The cloudy vinegar of the present invention has a cell count of acetic acid bacteria of 1.0 x 10 8By adjusting the concentration of bacteria to 5% (w / v) or more and the dry weight of the solid content to 5% (w / v) or more and 18% (w / v) or less, the number of bacteria can be sufficiently increased while suppressing impurities. This allows the original taste and flavor of acetic acid bacteria to be enjoyed with the unpleasant taste caused by impurities suppressed, and the rich, fragrant fermented feeling derived from acetic acid bacteria to be felt. Furthermore, the cloudy vinegar of the present invention has a unique deep flavor of fermentation, and can achieve a mellow and good mouthfeel while enhancing the refreshing acidity and aroma typical of vinegar. Therefore, according to the present invention, it is possible to provide cloudy vinegar that has a flavor and mouthfeel that is easy to ingest, in addition to being able to enjoy the bioregulation function of acetic acid bacteria.

[0026] <How to make cloudy vinegar> The method for producing cloudy vinegar of the present invention is a method for producing cloudy vinegar containing acetic bacteria and having an acidity of 4% or more by growing acetic bacteria, and is characterized by including an acetic acid fermentation step in which acetic acid fermentation is performed in a medium containing pre-grown acetic bacteria. The present inventors have found that when acetic bacteria are grown in a medium with a high acetic acid concentration, the growth efficiency of the acetic acid bacteria is suppressed. For this reason, the present inventors have conceived of growing acetic bacteria in a medium with an acetic acid concentration below a certain level, and then performing acetic acid fermentation in the medium containing the pre-grown acetic bacteria, thereby achieving both an increase in the number of acetic acid bacteria cells and an increase in the efficiency of acetic acid fermentation.

[0027] <Acetic acid fermentation process> In the acetic acid fermentation step of the present invention, ethanol or the like is added to a medium containing pre-grown acetic acid bacteria to carry out acetic acid fermentation. The pre-grown acetic acid bacteria may be live or dead. When the pre-grown acetic acid bacteria are dead, live acetic acid bacteria for acetic acid fermentation may be inoculated into the medium. In addition, the production method of the present invention may not include a step of filtering the medium after the acetic acid fermentation step. This allows the production of 1.0×10 8It becomes easier to ensure a cell count of acetic acid bacteria of 300 / mL or more, and cloudy vinegar with clear turbidity due to the cells can be produced. Furthermore, the production method of the present invention preferably does not include a step of mixing two or more vinegars each produced by a production method including an acetic acid fermentation step. In other words, it is preferable that the cloudy vinegar of the present invention is produced by a production method including a single acetic acid fermentation step. This makes it possible to suppress the unpleasant taste of the cloudy vinegar and enhance the fermented feel. The production method of the present invention having such an acetic acid fermentation step will be specifically described below by taking two embodiments as examples. Note that the production method of the present invention is not limited to the following two embodiments.

[0028] <First embodiment of the method for producing cloudy vinegar> The method for producing cloudy vinegar according to the first embodiment is characterized in that it includes a growth step of growing acetic acid bacteria prior to the acetic acid fermentation step.

[0029] [Proliferation process] In the growth step of this embodiment, acetic bacteria are grown in a medium for growing acetic bacteria. Therefore, the acetic bacteria used in this step are viable bacteria. The growth medium used in this step may contain known components used for growing acetic bacteria, and may contain components that are generally used as fermentation nutrient sources for acetic bacteria, such as sugars such as fruit juice, yeast extract, organic nitrogen sources such as peptone and tryptone, and inorganic nitrogen sources such as ammonium salts and nitrates. Furthermore, from the viewpoint of increasing the growth efficiency of acetic bacteria, the growth medium used in this step preferably has an acidity of 1% or less, more preferably 0.5% or less, and more preferably does not contain acetic acid. In this step, the number of bacteria is, for example, 1×10 7 The number of acetic acid bacteria grown in this step should be increased to 3×10 7 The number of cells / mL or more is preferably 5×10 7It is preferable that the concentration is more than 1 / mL. In this step, the acetic acid bacteria can be grown by making the medium low in acidity or the like, which minimizes stress on the acetic acid bacteria, and the growth efficiency of the acetic acid bacteria can be increased. In addition, at the start of the culture in this step, the density of acetic acid bacteria (viable bacteria) in the medium is low, creating an environment with little stress from other bacteria, which also increases the growth efficiency of the acetic acid bacteria.

[0030] [Acetic acid fermentation process (first embodiment)] In the acetic acid fermentation step of this embodiment, ethanol is added to a medium containing the acetic acid bacteria grown in the growth step to carry out acetic acid fermentation. The medium used in the acetic acid fermentation step may be the medium used in the growth step to which ethanol has been added, and may further include fermentation nutrient sources, acetic acid, etc. Ethanol may be added all at once at the start of acetic acid fermentation, or may be added in several portions from the start to the end of acetic acid fermentation. In this step, acetic acid fermentation is preferably carried out using only the acetic acid bacteria grown in the growth step, but new live bacteria may also be added.

[0031] <Second embodiment of the method for producing cloudy vinegar> The method for producing cloudy vinegar according to the second embodiment of the present invention is characterized in that in the acetic acid fermentation step, an additive containing acetic acid bacteria that contains the cells of grown acetic acid bacteria is added to perform acetic acid fermentation. Note that the production method according to this embodiment may further include a preparation step of preparing the additive containing acetic acid bacteria prior to the acetic acid fermentation step.

[0032] [Additives containing acetic acid bacteria] In this embodiment, the acetic acid bacteria-containing additive contains the cells of the grown acetic acid bacteria. The acetic acid bacteria-containing additive may contain uncrushed cells, or may contain partially crushed cells. The acetic acid bacteria contained in the acetic acid bacteria-containing additive may be dead or live, but it is particularly preferable that the dead bacteria are used. It is considered that the stress of the live bacteria performing acetic acid fermentation can be further reduced by adding dead bacteria to the medium, and the fermentation efficiency can be improved. Specific examples of the acetic acid bacteria-containing additive include a medium in which acetic acid bacteria are grown, a concentrated product of the medium, and an extract in which acetic acid bacteria cells are extracted from the medium. In particular, the acetic acid bacteria-containing additive is preferably a concentrated product of a medium in which acetic acid bacteria are grown, from the viewpoint of efficiently adding acetic acid bacteria to the medium to which the additive is added.

[0033] [Acetic acid fermentation process (second embodiment)] In the acetic acid fermentation process of this embodiment, the acetic acid bacteria-containing additive is added to a medium containing ethanol to perform acetic acid fermentation. When the acetic acid bacteria-containing additive contains dead bacteria, live bacteria are further added to the medium. The acetic acid bacteria-containing additive may be added at any timing in the acetic acid fermentation process, and may be added once or multiple times. By adding the acetic acid bacteria-containing additive after the start of this process, particularly in the middle or later stages, it is possible to suppress a decrease in the efficiency of acetic acid fermentation due to overcrowding of acetic acid bacteria. The medium used in this process may contain, in addition to ethanol, components that are generally used as fermentation nutrient sources for the above-mentioned acetic acid bacteria, and may further contain acetic acid.

[0034] <Fermentation method> The fermentation method used in the production method of the present invention includes aeration fermentation, static fermentation (surface fermentation), shaking fermentation, etc., and it is particularly preferable to use aeration fermentation. Aeration fermentation is a fermentation method in which air is taken in while stirring, and can increase the growth efficiency and fermentation efficiency of live bacteria. In addition, compared to static fermentation, there is less contamination by other bacteria, and unpleasant flavors can be further reduced.

[0035] <Effects of the method for producing cloudy vinegar> In the production method of the present invention, acetic acid fermentation is performed in a medium containing pre-grown acetic acid bacteria, and the number of acetic acid bacteria is increased to 1.0 × 10 while the acidity is sufficiently increased to 4% or more. 8 In addition, by increasing the efficiency of acetic acid bacteria proliferation, the time required to produce cloudy vinegar can be shortened, and the risk of contamination can be reduced. This allows the number of acetic acid bacteria to be increased to 1.0 × 10 8 The concentration of acetic acid bacteria in the vinegar can be increased to 50 ... EXAMPLES

[0036] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention should not be construed as being limited to the following descriptions. In the medium compositions below, "%" indicates "% (w / v)".

[0037] <Test Example 1: Examination of the method of producing cloudy vinegar and the number of acetic acid bacteria> [Production of cloudy vinegar] Example 1 In Example 1, cloudy vinegar was produced by the production method according to the first embodiment described above. First, in the proliferation step, live cells of the acetic acid bacteria Gluconacetobacter hansenii were added to a culture medium for proliferation of the acetic acid bacteria. The culture medium contained 10% concentrated apple juice (7 times concentrated), yeast extract, inorganic nutrients, and fresh water. The acetic acid bacteria were then subjected to aeration fermentation for about 20 hours under conditions of a temperature of 30°C and an aeration rate per culture medium of 0.1 L / min. Next, in the acetic acid fermentation step, the number of bacteria in the proliferation step was increased to 5×10 7 Ethanol was added to the medium in which the number of acetic acid bacteria was increased to 1 / mL until the acidity of the medium reached 4% or more, and aeration fermentation was carried out under the same conditions as in the growth step. This medium (fermentation liquid) containing acetic acid bacteria was used as the cloudy vinegar of Example 1 without filtration.

[0038] Example 2 In Example 2, cloudy vinegar was produced by the production method according to the second embodiment described above. First, an acetic acid bacteria-containing additive containing the same killed acetic acid bacteria as in Example 1 was added to a medium containing ethanol, and the number of bacteria contained in the medium was increased to 5×10 7 The concentration was adjusted to 1 / mL. Furthermore, live acetic acid bacteria were added to carry out acetic acid fermentation. The acetic acid bacteria-containing additive was prepared by concentrating and sterilizing a medium in which the same acetic acid bacteria as in Example 1 was grown. The medium contained 10% concentrated apple juice (7 times concentrated), 4.5% ethanol, 0.4% acetic acid, yeast extract, inorganic nutrients, and fresh water. In Example 2, the acetic acid bacteria-containing additive was added so as to achieve the bacterial concentration shown in Table 1. The timing of addition of the acetic acid bacteria-containing additive was at the start of fermentation. The conditions for acetic acid fermentation were the same as those for the acetic acid fermentation process in Example 1. Using the above medium, aeration fermentation was carried out until the acidity reached 4% or more, and the cloudy vinegar of Example 2 was produced without filtration.

[0039] Example 3 The cloudy vinegar of Example 3 was produced in the same manner as in Example 2, except that an acetic acid bacteria-containing additive containing the same killed bacteria as in Example 2 was added appropriately to achieve the bacterial concentration shown in Table 1.

[0040] Example 4 The cloudy vinegar of Example 4 was produced in the same manner as in Example 2, except that an acetic acid bacteria-containing additive containing the same killed bacteria as in Example 2 was added appropriately to achieve the bacterial concentration shown in Table 1.

[0041] Example 5 The cloudy vinegar of Example 5 was produced by adding 0.3% fermented cellulose to the cloudy vinegar of Example 3.

[0042] Example 6 In Example 6, a different acetic acid bacteria, Acetobacter pasteurianus, from Examples 1 to 5 was used to produce cloudy vinegar by the production method according to the second embodiment described above. First, an acetic acid bacteria-containing additive containing dead acetic acid bacteria was added to a medium containing rice saccharification liquid with 13% rice content, 4.5% ethanol, inorganic nutrients, and fresh water, and live acetic acid bacteria were further added to perform acetic acid fermentation. The acetic acid bacteria-containing additive was produced in the same manner as the acetic acid bacteria-containing additive of Example 2, except that the acetic acid bacteria was used. The acetic acid bacteria-containing additive was adjusted to the bacterial concentration in Table 1. Aeration fermentation was performed under the same conditions as in Example 2 until the acidity of the medium reached 4% or more, and the cloudy vinegar of Example 6 was obtained without filtration.

[0043] Example 7 The cloudy vinegar of Example 7 was produced in the same manner as in Example 6, except that an acetic acid bacteria-containing additive containing the same dead bacteria as in Example 6 was added appropriately to achieve the bacterial concentration shown in Table 1.

[0044] Example 8 The cloudy vinegar of Example 8 was produced in the same manner as in Example 6, except that an acetic acid bacteria-containing additive containing the same dead bacteria as in Example 2 was added appropriately to achieve the bacterial concentration shown in Table 1.

[0045] Example 9 The cloudy vinegar of Example 9 was produced in the same manner as in Example 3, using the same acetic acid bacteria as in Example 1, except that the medium composition was changed to rice saccharification liquid (rice content: 10%), ethanol: 4.5%, acetic acid: 0.4%, inorganic nutrients, and clean water.

[0046] Comparative Example 1 In addition to the same process as in Example 2, the cloudy vinegar of Comparative Example 1 was produced by mixing brewed vinegar from which acetic acid bacteria had been removed by filtration.

[0047] Comparative Example 2 The cloudy vinegar of Comparative Example 2 was produced by mixing cloudy vinegar prepared by the same process as in Example 2 with brewed vinegar with a high solids content (30% concentrated apple juice (7 times concentrated), 0.4% acetic acid, 4.5% ethanol, inorganic nutrients, and clean water).

[0048] Comparative Example 3 The cloudy vinegar of Comparative Example 3 was a commercially available cloudy vinegar produced by static fermentation using steamed rice. Generally, in static fermentation, a film of acetic acid bacteria is floated on top of a preparation liquid adjusted to an acidity (as acetic acid) of about 1 to 2% and ethanol of about 4%, and acetic acid fermentation is carried out until the acidity reaches 4% or more. It is assumed that the cloudy vinegar of Comparative Example 3 was produced without filtration after static fermentation, and sterilized as necessary.

[0049] [Acidity measurement] The acidity of each sample of Examples 1 to 9 and Comparative Examples 1 to 3 was calculated by the following method (neutralization titration method: quantitative formula). First, a sample was accurately collected and diluted 10 times with ion-exchanged water, and two drops of 0.1% phenolphthalein solution were added to the diluted solution (100 g) as an indicator, and neutralization titration was performed with 0.1 mol / L sodium hydroxide solution of known titer, and the acidity of the sample solution was calculated by the following formula. As a result, the acidity of each of the samples of Examples 1 to 9 and Comparative Examples 1 to 3 was 4.5 (see Table 1). Acidity of sample (%) = {(60.05 x 0.1 x F x V) x 100} / {amount of sample taken (10 g) x 1000} 60.05: Molecular weight of acetic acid 0.1: Molar concentration of sodium hydroxide solution (mol / L) F: Potency of 0.1 mol / L sodium hydroxide solution V: Titration volume of 0.1 mol / L sodium hydroxide solution (mL)

[0050] [Table 1]

[0051] [Evaluation of bacterial count] Samples were taken from each of the cloudy vinegars of Examples 1 to 9 and Comparative Examples 1 to 3, and each sample was diluted with phosphate buffered saline so that 5 to 10 bacterial cells were present in one square of a blood plate. The diluted sample was poured into a Thoma blood plate and left to stand for several minutes to several tens of minutes to allow the bacterial cells to settle. The number of acetic acid bacteria cells in each square was counted by observation under a microscope. For chains of acetic acid bacteria, the number of individual acetic acid bacteria cells constituting the chain was counted. Approximately 80 to 100 squares were counted to calculate the average number of bacterial cells per square, and the number of bacterial cells per mL was calculated using the following formula. Number of acetic acid bacteria (units / 1mL) = (average number of bacteria per square / volume of one square) x dilution ratio

[0052] As shown in Table 1, the bacterial count of each of the cloudy vinegars of Examples 1 to 9 was 1.0 × 10 8 On the other hand, the bacterial counts of the cloudy vinegars of Comparative Examples 1 to 3 were all 1.0 × 10 8 In addition, in the groups of Examples 2, 3, and 4, and the groups of Examples 6, 7, and 8, in which the amount of the additive containing acetic acid bacteria was changed, a tendency was confirmed that the greater the amount of the additive containing acetic acid bacteria added, the greater the number of bacterial cells.

[0053] [Evaluation of the proportion of major acetic acid bacteria] The proportion of the main acetic acid bacteria in the total bacterial cells contained in the cloudy vinegar was measured by visually classifying the types of bacterial cells from the images used for counting the number of bacterial cells. As a result, as shown in Table 1, the main acetic acid bacteria accounted for 100% of the total bacterial cells in the cloudy vinegars of Examples 1 to 9 and Comparative Examples 1 and 2 produced by aerobic fermentation, and the main acetic acid bacteria accounted for 33% of the total bacterial cells in the cloudy vinegar of Comparative Example 3 produced by surface fermentation.

[0054] FIG. 1 shows an image of the sample of Example 1 enlarged 600 times, and FIG. 2 shows an image of the sample of Comparative Example 3 enlarged 600 times. In the image of FIG. 2, in addition to the main acetic acid bacteria 1b, which is a bacillus, round yeast 2 and other contaminants (such as parts of fruit) 3 other than the bacteria were also present. On the other hand, in the image of FIG. 1, the main acetic acid bacteria 1a, which is a bacillus, were abundant, but yeast and other contaminants were scarce. When the inventors also checked the images of other Examples, they showed the same tendency as FIG. 1. Thus, the cloudy vinegar of the Example of the present invention tended to have a higher proportion of the main acetic acid bacteria and less yeast and other contaminants than the cloudy vinegar of Comparative Example 3.

[0055] [Evaluation of dry weight of solids] 1 mL of each of the cloudy vinegar samples from Examples 1 to 9 and Comparative Examples 1 to 3 was collected and evaporated to dryness in a hot water bath, then dried by placing in a dry heat thermostatic chamber at 105° C. for 2 hours and 30 minutes. The weight of the sample after drying was measured, and the dry weight of the solid content was calculated using the following formula. The results are shown in Table 1. Dry weight (% (w / v)) = sample weight after drying (g) / sample volume before drying (mL) × 100

[0056] As shown in Table 1, the dry weight of each of the cloudy vinegars of Examples 1 to 9 was 5% (w / v) or more and 18% (w / v) or less. On the other hand, the dry weight of each of the samples of Comparative Example 1 and Comparative Example 3 was less than 5% (w / v). Moreover, the dry weight of the sample of Comparative Example 2 was more than 18% (w / v).

[0057] [Evaluation of wet weight of acetic acid bacteria] A 10 mL sample was taken from each of the cloudy vinegars of Examples 1 to 9 and Comparative Examples 1 to 3, and after centrifugation (6000 G, 5 min), the supernatant was removed, and the weight of the resulting precipitate was recorded as the wet weight.

[0058] As shown in Table 1, among the cloudy vinegars of Examples 1 to 9 and Comparative Examples 1 to 3, the wet weight of acetic acid bacteria in the cloudy vinegars of Examples 1 to 3, 6 and 9 and Comparative Example 1 was less than 1% (w / v).

[0059] [Evaluation of fermentation sensation] A number of trained panels put the cloudy vinegars of Examples 1 to 9 and Comparative Examples 1 to 3 in their mouths and evaluated the rich fermented feeling derived from bacteria based on the evaluation criteria shown below. The "rich fermented feeling derived from bacteria" was evaluated as a savory, rich flavor unique to acetic acid bacteria, other than the aroma derived from raw materials such as fruit juice and grains. Each cloudy vinegar of Examples 1 to 9 and Comparative Examples 1 to 3 was scored from 1 to 4 points in increments of 0.5 points, and the average score was calculated. An average score of 2.0 points or more was considered to be a pass. The results are shown in Table 1. (Evaluation standard for the rich fermented feeling derived from bacteria) 1: The rich fermented taste derived from acetic acid bacteria is weak or not noticeable. 2: Feel the rich fermentation sensation from the acetic acid bacteria 3. You can fully feel the rich fermentation sensation derived from acetic acid bacteria. 4: You can feel the rich fermentation from the acetic acid bacteria.

[0060] As shown in Table 1, the cloudy vinegars of Examples 1 to 9 all had a fermentation sensation score of 2.0 points or more. On the other hand, the cloudy vinegars of Comparative Examples 1 to 3 all had a fermentation sensation score of less than 2.0 points. This indicates that in cloudy vinegars containing acetic acid bacteria and having an acidity of 4% or more, the number of acetic acid bacteria cells is 1.0×10 8 It was found that by setting the concentration to 5% (w / v) or more and the dry weight of the solids to 5% (w / v) or more and 18% (w / v) or less, the rich fermented flavor derived from the acetic acid bacteria could be felt.

[0061] In addition, from the results of the groups of Examples 2, 3, and 4 and the groups of Examples 6, 7, and 8, which adopted the same manufacturing method but changed the bacterial species, it was found that even if the bacterial species of the acetic acid bacteria was changed, a sufficient fermented feeling could be obtained in all cases by adjusting the number of acetic acid bacteria cells and the dry weight of solids within the above range. Furthermore, when comparing the groups of Examples 2, 3, and 4 with the groups of Examples 6, 7, and 8, it was found that the evaluation of the fermented feeling tended to be slightly lower in the examples (Examples 4 and 8) in which the number of acetic acid bacteria cells was high. This suggests that by optimizing the number of acetic acid bacteria cells, it is possible to suppress unpleasant flavors and enhance the fermented feeling derived from the acetic acid bacteria.

[0062] Furthermore, the results of Examples 1 and 6 show that even when the wet weight is less than 1.0% (w / v), a cloudy vinegar with a sufficiently high number of acetic acid bacteria cells and a sufficiently fermented feel can be obtained.

[0063] <Test Example 2: Examination of the acidity of cloudy vinegar> [Production of cloudy vinegar] In Examples 10 and 12, the acetic acid in the medium at the start of the culture was 2.5%, and aeration fermentation was performed so that the final acidity of the medium was 6.5% (see Table 2). In Example 11, the acetic acid in the medium at the start of the culture was 4.5%, and aeration fermentation was performed until the final acidity was 8.5% (see Table 2). The cloudy vinegars of Examples 10 to 12 were produced in the same manner as in Example 2. In Examples 10 and 11, the same acetic acid bacteria Gluconacetobacter hansenii as in Examples 1 to 5 was used. In Example 12, the same acetic acid bacteria Acetobacter pasteurianus as in Example 6 was used. The acidity was measured in the same manner as in Test Example 1.

[0064] [Table 2]

[0065] [Evaluation of bacterial count] As in Test Example 1, the bacterial counts of the cloudy vinegars of Examples 10 to 12 were measured. As shown in Table 2, the bacterial counts of the cloudy vinegars of Examples 10 to 12 were all 1.0 × 10 8 The number of cells / mL or more was higher.

[0066] [Evaluation of the proportion of major acetic acid bacteria] As in Test Example 1, the proportion of the main acetic acid bacteria in each of the cloudy vinegars of Examples 10 to 12 was measured, and it was found that the main acetic acid bacteria accounted for 100% of the total bacterial cells in all cases.

[0067] [Evaluation of dry weight of solids] As in Test Example 1, the dry weight of the solid content in each of the nigori vinegars of Examples 10 to 12 was measured, and the dry weight was 5% (w / v) or more and 18% (w / v) or less in all cases.

[0068] [Evaluation of wet weight of acetic acid bacteria] As in Test Example 1, the wet weight of acetic acid bacteria in each of the cloudy vinegars of Examples 10 to 12 was measured. In Examples 10 and 11, the wet weight of acetic acid bacteria was less than 1% (w / v).

[0069] [Evaluation of fermentation sensation] As in Test Example 1, the fermented feeling of each of the cloudy vinegars of Examples 10 to 12 was evaluated, and all of them had a score of 2.0 points or more. Of these, Examples 10 and 12, which have an acidity of 6.5%, had a higher score for the fermented feeling than Example 11, which has an acidity of 8.5%, and a lower score for the fermented feeling than Example 2, which has an acidity of 4.5%. This result showed a tendency for the fermented feeling to decrease as the acidity increases.

[0070] <Summary> From the above, in cloudy vinegar containing acetic acid bacteria with an acidity of 4% to 9%, the number of acetic acid bacteria is 1.0 × 10 8 It was found that by setting the concentration at 5% (w / v) or more and the dry weight of the solids at 5% (w / v) or more and 18% (w / v) or less, unpleasant flavors were suppressed and the rich fermented flavor derived from the acetic acid bacteria could be felt. [Explanation of symbols]

[0071] 1a, 1b…Acetic acid bacteria 2…Yeast 3. Impurities

Claims

1. A cloudy vinegar containing acetic acid bacteria and having an acidity of 4% to 9%. The main acetic acid bacteria, which account for more than 90% of the bacterial cells contained in the cloudy vinegar, are one type of acetic acid bacteria selected from the genera Gluconoacetobacter, Acetobacter, Gluconobacter, Komagataebacter, and Nobuacetimonas, The number of acetic acid bacteria is 1.0 × 10 ８ / mL or more, The dry weight of the solid content is 5% (w / v) or more and 18% (w / v) or less. Cloudy vinegar is characterized by its

2. Also contains fruit juice The cloudy vinegar according to claim 1.

3. The wet weight of the acetic acid bacteria is less than 1% (w / v). The cloudy vinegar according to claim 1 or 2.

4. A method for producing cloudy vinegar containing acetic acid bacteria and having an acidity of 4% to 9% The method includes the step of carrying out acetic acid fermentation in a medium containing the acetic acid bacteria that have been grown in advance, The main acetic acid bacteria, which account for more than 90% of the bacterial cells contained in the cloudy vinegar, are one type of acetic acid bacteria selected from the genera Gluconoacetobacter, Acetobacter, Gluconobacter, Komagataebacter, and Nobuacetimonas, The number of acetic acid bacteria is 1.0 × 10 ８ / mL or more, The dry weight of the solid content is 5% (w / v) or more and 18% (w / v) or less. A method for producing cloudy vinegar, comprising the steps of:

5. The medium contains 1×10 ７ The present invention is characterized by containing more than 1000 / mL of The method for producing cloudy vinegar according to claim 4.

6. In the acetic acid fermentation step, an acetic acid bacteria-containing additive containing the grown acetic acid bacteria cells is added to a medium containing ethanol to carry out acetic acid fermentation. The method for producing cloudy vinegar according to claim 4.

7. The method does not include a step of filtering the medium after the acetic acid fermentation step. The method for producing cloudy vinegar according to any one of claims 4 to 6.

Images