Unfiltered vinegar, method for producing unfiltered vinegar, and food composition

Abstract

To provide unfiltered vinegar containing many acetic acid bacterial cells and giving a feeling of fermentation derived from acetic acid bacteria, a method for producing the same, and a food composition containing the same. The unfiltered vinegar of the present invention contains acetic acid bacteria and has an acidity of from 4% to 9% and is characterized in that the major acetic acid bacteria accounting for 90% or more of the cells contained in the unfiltered vinegar are one type of acetic acid bacteria selected from the Gluconoacetobacter sp., Acetobacter sp., Gluconobacter sp., Komagataeibacter sp., and Nobuacetimonas sp., the cell count of the acetic acid bacteria is 1.0×108 / mL or more, and the dry weight of the solids fraction is from 5% (w / v) to 18% (w / v).

Description

Cloudy vinegar, method for producing cloudy vinegar, and food composition

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

[0002] Vinegar is produced by acetic acid fermentation using acetic acid bacteria in a culture medium containing ethanol, etc. In general vinegar, acetic acid bacteria cause turbidity and are therefore removed by filtration, etc. However, in recent years, acetic acid bacteria have been found to have functions 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 with efficiently enhanced aldehyde-oxidizing ability, which contains a specific acetic acid bacterium, has a turbidity at a wavelength of 660 nm (OD660 nm) of 1 to 10, and has an aldehyde dehydrogenase activity per 15 mL of the acetic acid bacteria culture solution of 4 to 60. Furthermore, Patent Document 2 discloses vinegar containing fermented cellulose and acetic acid, and further containing acetic acid bacteria cells.

[0004] JP 2017-195807 A JP 2020-210 A

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

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

[0007] The present inventors have conducted extensive research to achieve the above-mentioned object. As a result, they have found that increasing the number of acetic acid bacteria cells increases the unpleasant taste, but under certain conditions, the fragrant and rich fermented flavor derived from acetic acid bacteria can be felt. The present inventors further investigated the conditions under which a stable fermented flavor can be obtained, and found that the content of acetic acid bacteria is increased to 1.0 x 10 in terms of bacterial cell count. ８ / mL or more and the dry weight of the solids is adjusted to 5% (w / v) or more and 18% (w / v) or less, it has been found that a cloudy vinegar containing a large amount of acetic acid bacteria cells can be obtained that still has a fragrant and rich fermented flavor derived from the acetic acid bacteria, and this has 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% inclusive, wherein the main acetic acid bacteria that account for 90% or more of the bacterial cells contained in the cloudy vinegar is one acetic acid bacterium selected from the genus Gluconoacetobacter, Acetobacter, Gluconobacter, Komagataebacter, and Nobuacetimonas, and the number of bacterial cells of the acetic acid bacterium is 1.0 x 10 ８ (1) A cloudy vinegar characterized by having a dry weight of solids of 5% (w / v) or more and 18% (w / v) or less, (2) the cloudy vinegar according to (1), further containing fruit juice, (3) the cloudy vinegar according to (1) or (2), in which the wet weight of the acetic acid bacteria cells is less than 1% (w / v), (4) a method for producing cloudy vinegar containing acetic acid bacteria and having an acidity of 4% or more and 9% or less, the method comprising an acetic acid fermentation step of carrying out acetic acid fermentation in a medium containing the acetic acid bacteria that have been grown in advance, and (5) the medium containing the acetic acid bacteria at a density of 1 x 10 ７ (6) A method for producing cloudy vinegar according to (4), characterized in that the number of cells of the acetic acid bacteria is 5.0 × 10 or more / mL; (7) A method for producing cloudy vinegar according to any one of (4) to (6), wherein the acetic acid fermentation step involves adding an acetic acid bacteria-containing additive containing the grown cells of the acetic acid bacteria to a medium containing ethanol to carry out acetic acid fermentation; (8) A method for producing cloudy vinegar according to any one of (4) to (6), wherein the number of cells of the acetic acid bacteria is 5.0 × 10 or more; １０ particles / mL or less, and even 2.0 x 10 １０ (9) The cloudy vinegar according to any one of (1) to (3), wherein the number of cells of the acetic acid bacteria is 2.0 × 10 or less / mL. ８ / mL or more, and 4.0 × 10 ８(10) The cloudy vinegar according to any one of (1) to (3) and (8), wherein the main acetic acid bacterium is one species of acetic acid bacterium selected from the genus Gluconoacetobacter and the genus Acetobacter; (4)' A method for producing cloudy vinegar containing acetic acid bacteria and having an acidity of 4% to 9% or less, comprising an acetic acid fermentation step of performing acetic acid fermentation in a medium containing the acetic acid bacterium that has been grown in advance, wherein the main acetic acid bacterium that accounts for 90% or more of the bacterial cells contained in the cloudy vinegar is one species of acetic acid bacterium selected from the genus Gluconoacetobacter, the genus Acetobacter, the genus Gluconobacter, the genus Komagataebacter, and the genus Nobuacetimonas, and wherein the number of bacterial cells of the acetic acid bacterium is 1.0 x 10 ８ (5)' The method for producing cloudy vinegar, wherein the culture medium contains 1 x 10 acetic acid bacteria / mL or more, and the dry weight of the solid content is 5% (w / v) or more and 18% (w / v) or less. ７ (6)' A method for producing cloudy vinegar according to (4)' or (5)', wherein in the acetic acid fermentation step, an acetic acid bacteria-containing additive containing pre-grown acetic acid bacteria cells is added to a medium containing ethanol to perform acetic acid fermentation; (7)' A method for producing cloudy vinegar according to any one of (4)' to (6)', which does not include a step of filtering the medium after the acetic acid fermentation step; (8)' A method for producing cloudy vinegar according to any one of (4)' to (6)', wherein the number of acetic acid bacteria cells is 5.0 x 10 １０ particles / mL or less, and even 2.0 x 10 １０ (9)' The method for producing cloudy vinegar according to any one of (4)' to (7)', wherein the number of cells of the acetic acid bacteria is 2.0 x 10 ８ / mL or more, and 4.0 × 10 ８(10)' The method for producing cloudy vinegar according to any one of (4)' to (8)', wherein the main acetic acid bacterium is one acetic acid bacterium selected from the genus Gluconoacetobacter and the genus Acetobacter; (11)' The method for producing cloudy vinegar according to any one of (4)' to (10)', further comprising a step of growing the acetic acid bacterium in a growth medium for acetic acid bacteria to an acidity of 1% or less, prior to the acetic acid fermentation step, to grow the acetic acid bacterium in advance; (12)' A food composition containing cloudy vinegar containing acetic acid bacteria and having an acidity of 4% to 9% or less, wherein the main acetic acid bacterium accounting for 90% or more of the bacterial cells contained in the cloudy vinegar is one acetic acid bacterium selected from the genus Gluconoacetobacter, the genus Acetobacter, the genus Gluconobacter, the genus Komagataebacter, and the genus Nobuacetimonas; The number of acetic acid bacteria in the cloudy vinegar is 1.0 × 10 ８ the dry weight of the solid content in the cloudy vinegar is 5% (w / v) or more and 18% (w / v) or less.

[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, a method for producing the same, and a food composition containing the same.

[0010] 1 is an image of cloudy vinegar according to an example (Example 1) of the present invention, magnified 600 times; and 2 is an image of cloudy vinegar according to a comparative example (Comparative Example 3) of the present invention, magnified 600 times.

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

[0012] <Features of the present invention> The present invention is a cloudy vinegar containing acetic acid bacteria and having an acidity of 4% or more, wherein the cloudy vinegar contains 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 solids 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 suppressed unpleasant taste and a rich fermented flavor derived from acetic acid bacteria. In the present invention, the "fermented flavor" 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] <Cloudy Vinegar> In the present invention, cloudy vinegar refers to vinegar with a turbidity. While typical vinegars undergo acetic acid fermentation by acetic acid bacteria and then undergo filtration or other processes to remove the acetic acid bacteria, the cloudy vinegar of the present invention retains its cloudiness due to the bacteria's cells without removing the acetic acid bacteria. The cloudy components in the cloudy vinegar of the present invention may contain components such as other bacteria, such as yeast, and fruit fibers, in addition to the acetic acid bacteria's cells. Furthermore, the cloudy vinegar of the present invention includes vinegars in which sediment settles at the bottom of the container and becomes cloudy upon stirring. Vinegar in the present invention refers to seasonings primarily composed of water and acetic acid, such as rice vinegar, black vinegar, five-grain vinegar, wine vinegar, apple vinegar, and tomato vinegar. The cloudy vinegar of the present invention is preferably brewed vinegar, since it provides a fermented flavor derived from acetic acid bacteria. As described below, the cloudy vinegar of the present invention is preferably produced through a single acetic acid fermentation process, rather than simply blending multiple different brewed vinegars produced through different acetic acid fermentation processes.

[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 acidity requirements for 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 fermented feeling 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 this makes the fermented feeling derived from acetic acid bacteria more strongly felt.

[0015] <Method for measuring acidity> First, accurately collect 10 g of cloudy vinegar as a sample and dilute it 10 times with ion-exchanged water. To the diluted solution (100 g), add two drops of 0.1% phenolphthalein solution as an indicator and neutralize titrate it with 0.1 mol / L sodium hydroxide solution of known potency. The acidity of the sample is calculated using the following formula: Acidity of sample (%) = {(60.05 x 0.1 x F x V) x 100} / {amount of sample collected (10 g) x 1000}, where 60.05 is the molecular weight of acetic acid, 0.1 is the molar concentration of the sodium hydroxide solution (mol / L), F is the potency of the 0.1 mol / L sodium hydroxide solution, and V is the titer of the 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 or 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 cloudy vinegar are typical acetic acid bacteria used in the production of brewed vinegar, and specifically, are one type of acetic acid bacteria selected from the genera Gluconacetobacter, Acetobacter, Gluconobacter, Komagataeibacter, and Novacetimonas. Furthermore, in the present invention, since a rich fermented taste derived from acetic acid bacteria can be easily obtained, the main acetic acid bacteria is preferably one selected from Gluconacetobacter hansenii, Gluconacetobacter liquefaciens, Komagataeibacter maltaceti, and Komagataeibacter medellinensis, and is particularly preferably Gluconacetobacter hansenii. In the present invention, the main acetic acid bacteria may account for 90% or more of the bacterial cells contained in the cloudy vinegar, preferably 92% or more, more preferably 95% or more, and even more preferably 98% or more.

[0017] <Number of Acetobacterial Cells> In the present invention, the number of acetic acid bacteria cells 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. ８In the present invention, the "cell count of acetic acid bacteria" refers to the total cell count of acetic acid bacteria contained in cloudy vinegar. 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 concentration is preferably 4.0 × 10 ８ Although there is no particular upper limit to the number of cells of the acetic acid bacteria, from the viewpoint of obtaining a good fermented taste with reduced unpleasant flavors, it is preferable that the number be 5.0 × 10 cells / mL or more. １０ It is preferable that the number of particles per mL is less than 2.0 × 10 １０ It is preferable that the bacterial cell count is equal to or less than 1 / mL. This bacterial cell count is the total number of live bacteria and dead bacteria. In the present invention, by using the bacterial cell count itself, rather than turbidity, as an indicator of the acetic acid bacteria cell count, the number of acetic acid bacteria cells excluding contaminants can be more accurately indicated. The number of acetic acid bacteria cells can be measured by the following method.

[0018] <How to calculate the number of acetic acid bacteria cells> (1) Dilute the sample so that each square of the hemocytometer contains 5 to 10 cells. It is recommended to use saline, phosphate-buffered saline, or pure water for dilution. (2) Inject the diluted sample into a Thoma hemocytometer. (3) Leave the sample to stand for several minutes to several tens of minutes to allow the cells to settle. (4) Count the number of cells in each square using a microscope. For chains of bacteria, count the number of individual acetic acid bacteria cells that make up the chain. Only count cells that maintain their original shape, excluding crushed cells. Furthermore, if multiple cells are present, count only cells with a shape that matches the characteristics of acetic acid bacteria described below. (5) To minimize variation within each square, count approximately 80 to 100 squares and calculate the average number of cells per square. (6) Calculate the number of cells per mL using the following formula: Number of acetic acid bacteria (cells / 1 mL) = (average number of bacteria per square / volume of one square) x dilution ratio

[0019] [Body Shape of Acetate Bacteria] In the production of brewed vinegar, acetic acid fermentation is carried out using acetic acid bacteria. Therefore, elongated bacilli are acetic acid bacteria, and can be distinguished from round-shaped bacteria such as yeast (see Figures 1 and 2 described below). Furthermore, the size of acetic acid bacteria is 1 to 5 μm, smaller than the cells of yeast and the like. Thus, in the cell counting method (4) above, acetic acid bacteria can be distinguished from other contaminating bacteria by visual inspection or image analysis. Examples of bacilli that can grow in vinegar include lactic acid bacteria and Bacillus subtilis. When these bacteria are present, 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 present, the proportion of each type of acetic acid bacteria can be calculated by genetic analysis.

[0020] <Dry weight of solid content> 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 solids to a range of 5% (w / v) to 18% (w / v) while containing a large number of bacterial cells / mL or more, it is possible to realize a cloudy vinegar that suppresses unpleasant flavors and has a fermented flavor derived from acetic acid bacteria. Furthermore, the lower limit of the dry weight of the solids is preferably 7% (w / v) or more, and even better 9% (w / v) or more, from the viewpoint of ensuring a sufficient number of bacterial cells and achieving a fermented flavor. Furthermore, the upper limit of the dry weight of the solids is preferably 16% (w / v) or less, and even better 15% (w / v) or less, from the viewpoint of more effectively suppressing unpleasant flavors.

[0021] <Method for measuring the dry weight of solids> A 1 mL sample was taken from the cloudy vinegar, and this sample was evaporated to dryness in a hot water bath, and then dried by placing it in a dry heat thermostatic chamber at 105°C for 2 hours and 30 minutes. The dried sample was cooled in a desiccator for 30 to 60 minutes, after which its weight was measured, and the dry weight of the solids was calculated using the following formula: Dry weight of solids (% (w / v)) = Sample weight 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 the salt from the dry weight. The weight of salt can be measured using the Mohr method or the like.

[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, and tomato juice, 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 cells> The cloudy vinegar of the present invention is characterized by a high 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 can be easily kept low. Therefore, in the cloudy vinegar of the present invention, the wet weight of acetic acid bacteria cells is preferably less than 1 (w / v)%, and even more preferably 0.7 (w / v)% or less. In the present invention, the "wet weight of 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 after centrifugation (6000 G, 5 min) and removal of the supernatant.

[0024] <Other Ingredients> In addition to the above-mentioned ingredients, the cloudy vinegar of the present invention can contain various ingredients commonly used in vinegar, selected and blended as appropriate, as long as the effects of the present invention are not impaired. Examples of other ingredients include amino acids, salt, sweeteners, thickeners, etc.

[0025] <Action and effect of cloudy vinegar of the present invention> The cloudy vinegar of the present invention has a cell count of acetic acid bacteria of 1.0 × 10８ By adjusting 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 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 flavor derived from acetic acid bacteria to be felt. Furthermore, the cloudy vinegar of the present invention has a unique, deep flavor of fermentation, which enhances the refreshing acidity and aroma characteristic of vinegar while achieving a mellow and pleasant mouthfeel. Therefore, according to the present invention, in addition to being able to enjoy the bioregulatory function of acetic acid bacteria, it is possible to provide cloudy vinegar that has a flavor and mouthfeel that is easy to consume.

[0026] <Uses of Cloudy Vinegar> The cloudy vinegar of the present invention can be used to obtain health benefits provided by acetic acid bacteria. For example, the cloudy vinegar of the present invention can be used for at least one purpose selected from the maintenance and / or improvement of immune function, reduction of allergic inflammation, increased secretion of immunoglobulin A antibodies, improvement of aldehyde dehydrogenase activity, and improvement of aldehyde oxidation ability.

[0027] <Food Compositions Containing Cloudy Vinegar> The present invention can provide various food compositions containing the cloudy vinegar described above, within the scope that does not impair the above-mentioned effects. Examples of such food compositions include beverages, supplements, seasonings, and other processed foods.

[0028] <Method for Producing Cloudy Vinegar> The method for producing cloudy vinegar of the present invention is a method for producing cloudy vinegar containing acetic acid bacteria and having an acidity of 4% or more by growing acetic acid 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 acid bacteria. The inventors have found that growing acetic acid bacteria in a medium with a high acetic acid concentration inhibits the growth efficiency of the acetic acid bacteria. Therefore, the inventors have conceived the idea of ​​growing acetic acid 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 acid bacteria, thereby achieving both an increase in the number of acetic acid bacteria cells and efficient acetic acid fermentation.

[0029] <Acetic acid fermentation step> 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. Furthermore, the production method of the present invention preferably does not include a step of filtering the medium after the acetic acid fermentation step. This allows for a 1.0 x 10 ８ This makes it easier to ensure a bacterial cell count of acetic acid bacteria of 1000 or more / mL, making it possible to produce cloudy vinegar with a clear turbidity due to the bacterial cells. 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, the cloudy vinegar of the present invention is preferably 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. Below, the production method of the present invention having such an acetic acid fermentation step will be specifically explained using two embodiments as examples. Note that the production method of the present invention is not limited to the following two embodiments.

[0030] <First embodiment of method for producing cloudy vinegar> The method for producing cloudy vinegar according to the first embodiment is characterized by including a growth step of growing acetic acid bacteria in advance before the acetic acid fermentation step.

[0031] [Growth Step] In the growth step of this embodiment, acetic acid bacteria are grown in a growth medium for acetic acid bacteria. Therefore, the acetic acid bacteria used in this step are viable bacteria. The growth medium used in this step may contain known components used for growing acetic acid bacteria, and may contain components commonly used as fermentation nutrient sources for acetic acid bacteria, such as sugars such as fruit juice, organic nitrogen sources such as yeast extract, peptone, and tryptone, and inorganic nitrogen sources such as ammonium salts and nitrates. Furthermore, from the viewpoint of increasing the growth efficiency of acetic acid 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 bacterial cells is, for example, 1 x 10 ７ The number of acetic acid bacteria grown in this step is further increased to 3×10７ It is preferable that the number of cells / mL is 5×10 or more. ７ It is preferable that the concentration is at least 1 / mL. In this step, the acetic acid bacteria can be grown in a medium that minimizes stress on the acetic acid bacteria, for example by lowering the acidity of the medium, thereby increasing the growth efficiency of the acetic acid bacteria. Furthermore, 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.

[0032] [Acetic Acid Fermentation Process (First Embodiment)] In the acetic acid fermentation process of this embodiment, ethanol is added to a medium containing the acetic acid bacteria grown in the growth process to carry out acetic acid fermentation. The medium used in the acetic acid fermentation process may be the medium used in the growth process (medium for growing acetic acid bacteria) to which ethanol has been added, and may further contain 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 process, acetic acid fermentation is preferably carried out using only the acetic acid bacteria grown in the growth process, but new live bacteria may also be added.

[0033] <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 an acetic acid fermentation is carried out by adding an acetic acid bacteria-containing additive containing cells of acetic acid bacteria grown in a growth step. Note that the production method according to this embodiment may further include a preparation step of preparing the acetic acid bacteria-containing additive before the acetic acid fermentation step.

[0034] [Acetate bacteria-containing additive] In this embodiment, the acetic acid bacteria-containing additive contains acetic acid bacteria cells that have been grown in advance in the growth step. The acetic acid bacteria-containing additive may contain unpulverized cells, or may contain partially pulverized cells. The acetic acid bacteria contained in the acetic acid bacteria-containing additive may be killed or live, but killed cells are particularly preferable. It is believed that adding killed cells to a medium can further reduce stress on live bacteria that perform acetic acid fermentation, thereby improving fermentation efficiency. Specific examples of the acetic acid bacteria-containing additive include a medium in which acetic acid bacteria have been grown, a concentrated product of the medium, and an extract in which acetic acid bacteria cells have been 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 have been grown, from the viewpoint of efficiently adding acetic acid bacteria to the medium to which it is added.

[0035] [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 carry out 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 time during the acetic acid fermentation process, and may be added once or multiple times. Adding the acetic acid bacteria-containing additive after the start of this process, particularly from the middle stage onwards, can 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 commonly used as fermentation nutrient sources for acetic acid bacteria, and may further contain acetic acid.

[0036] <Fermentation Method> Fermentation methods used in the production method of the present invention include aeration fermentation, static fermentation (surface fermentation), shaking fermentation, etc., and aeration fermentation is particularly preferred. Aeration fermentation is a fermentation method in which air is introduced while stirring, and can improve the growth efficiency and fermentation efficiency of live bacteria. Furthermore, compared to static fermentation, there is less contamination by other bacteria, and unpleasant flavors can be further reduced.

[0037] <Effects of the method for producing cloudy vinegar> In the production method of the present invention, acetic acid fermentation is carried out in a medium containing acetic acid bacteria that have been grown in advance, and the number of acetic acid bacteria is increased to 1.0 × 10 while the acidity is sufficiently increased to 4% or more. ８Furthermore, by increasing the efficiency of acetic acid bacteria proliferation, the time required for producing 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 can be increased to 50 ...

[0038] The present invention will be explained 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 following medium compositions, "%" indicates "% (w / v)."

[0039] <Test Example 1: Examination of the manufacturing method of cloudy vinegar and the cell count of acetic acid bacteria> [Manufacturing cloudy vinegar] (Example 1) In Example 1, cloudy vinegar was manufactured using the manufacturing method according to the first embodiment described above. First, in the growth process, live cells of the acetic acid bacteria Gluconacetobacter hansenii were added to a culture medium for growing 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 approximately 20 hours at a temperature of 30°C and an aeration rate of 0.1 L / min per culture medium. Next, in the acetic acid fermentation process, the cell count was increased to 5 x 10 ７ The culture medium was diluted to 1000 cells / mL, and ethanol was added until the acidity of the medium reached 4% or higher. The medium was then subjected to aeration fermentation under the same conditions as in the growth step. This culture medium (fermentation liquid) containing acetic acid bacteria was used as the cloudy vinegar of Example 1 without filtration.

[0040] In Example 2, cloudy vinegar was produced by the production method according to the second embodiment. First, an acetic acid bacteria-containing additive containing killed acetic acid bacteria, the same as in Example 1, was added to a medium containing ethanol, and the number of bacteria in the medium was increased to 5×10 ７The concentration was adjusted to cells / mL. Live acetic acid bacteria were then added, and acetic acid fermentation was carried out. The acetic acid bacteria-containing additive was a concentrate prepared by concentrating and sterilizing a medium in which the same acetic acid bacteria as in Example 1 had been grown. The medium contained 10% concentrated apple juice (7-fold concentrated), 4.5% ethanol, 0.4% acetic acid, as well as yeast extract, inorganic nutrients, and fresh water. In Example 2, the acetic acid bacteria-containing additive was added to achieve the bacterial concentration shown in Table 1. The acetic acid bacteria-containing additive was added at the start of fermentation. The acetic acid fermentation conditions were the same as those for the acetic acid fermentation process in Example 1. Aeration fermentation was carried out using the above medium until the acidity reached 4% or higher, and the cloudy vinegar of Example 2 was produced without filtration.

[0041] (Example 3) 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.

[0042] (Example 4) 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.

[0043] Example 5 The cloudy vinegar of Example 5 was produced by adding 0.3% of fermented cellulose to the cloudy vinegar of Example 3.

[0044] Example 6 In Example 6, a different Acetobacter pasteurianus strain from those used in Examples 1 to 5 was used to produce cloudy vinegar by the production method according to the second embodiment. First, an acetic acid bacteria-containing additive containing killed acetic acid bacteria was added to a medium containing rice saccharified liquid (13% rice content), 4.5% ethanol, inorganic nutrients, and fresh water. Live acetic acid bacteria were then added, and acetic acid fermentation was carried out. The acetic acid bacteria-containing additive was prepared in the same manner as the acetic acid bacteria-containing additive of Example 2, except that the acetic acid bacteria described above was used. The acetic acid bacteria-containing additive was added to achieve the bacterial concentration shown in Table 1. Aeration fermentation was carried out under the same conditions as in Example 2 until the acidity of the medium reached 4% or higher, and the cloudy vinegar of Example 6 was obtained without filtration.

[0045] (Example 7) Cloudy vinegar of Example 7 was produced in the same manner as in Example 6, except that an acetic acid bacteria-containing additive containing killed bacteria similar to that in Example 6 was added appropriately to achieve the bacterial concentration shown in Table 1.

[0046] (Example 8) Cloudy vinegar of Example 8 was produced in the same manner as in Example 6, except that an acetic acid bacteria-containing additive containing killed bacteria similar to that of Example 2 was added appropriately to achieve the bacterial concentration shown in Table 1.

[0047] (Example 9) Using the same acetic acid bacteria as in Example 1, the cloudy vinegar of Example 9 was produced in the same manner as in Example 3, except that the composition of the culture medium was changed to rice saccharified liquid (rice content: 10%), ethanol: 4.5%, acetic acid: 0.4%, inorganic nutrients, and fresh water.

[0048] Comparative Example 1 Cloudy vinegar of Comparative Example 1 was produced by the same process as in Example 2, but by mixing brewed vinegar from which acetic acid bacteria had been removed by filtration.

[0049] (Comparative Example 2) The cloudy vinegar of Comparative Example 2 was produced by mixing the cloudy vinegar prepared in the same manner as in Example 2 with brewed vinegar with a high solid content (30% concentrated apple juice (7 times concentrated), 0.4% acetic acid, 4.5% ethanol, inorganic nutrients, and fresh water).

[0050] (Comparative Example 3) A commercially available cloudy vinegar produced by static fermentation using steamed rice was used as the cloudy vinegar of Comparative Example 3. Generally, in static fermentation, a film of acetic acid bacteria is floated on top of a brewing liquid adjusted to an acidity (as acetic acid) of about 1-2% and an ethanol content of about 4%, and acetic acid fermentation is carried out until the acidity reaches 4% or more. It is presumed that the cloudy vinegar of Comparative Example 3 was produced without filtration after static fermentation, and sterilized as necessary.

[0051] [Measurement of Acidity] 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. To the diluted solution (100 g), two drops of 0.1% phenolphthalein solution were added as an indicator, and the diluted solution was subjected to neutralization titration with a 0.1 mol / L sodium hydroxide solution of known potency, and the acidity of the sample solution was calculated using the following formula. As a result, the acidity of the samples of Examples 1 to 9 and Comparative Examples 1 to 3 was all 4.5 (see Table 1). Acidity of sample (%) = {(60.05 x 0.1 x F x V) x 100} / {amount of sample (10 g) x 1000} 60.05: molecular weight of acetic acid 0.1: molar concentration of sodium hydroxide solution (mol / L) F: titer of 0.1 mol / L sodium hydroxide solution V: titer of 0.1 mol / L sodium hydroxide solution (mL)

[0052]

[0053] [Evaluation of bacterial cell 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 determined using the following formula: Number of acetic acid bacteria cells (cells / 1 mL) = (average number of bacteria per square / volume of one square) × dilution factor

[0054] As shown in Table 1, the bacterial counts of the cloudy vinegars of Examples 1 to 9 were all 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 Furthermore, within 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 varied, a tendency was confirmed in which the number of bacterial cells increased as the amount of the additive containing acetic acid bacteria increased.

[0055] [Evaluation of the proportion of major acetic acid bacteria] The proportion of major 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 in counting the number of bacterial cells. As a result, as shown in Table 1, in the cloudy vinegars of Examples 1 to 9 and Comparative Examples 1 and 2 produced by aerobic fermentation, the major acetic acid bacteria accounted for 100% of the total bacterial cells, while in the cloudy vinegar of Comparative Example 3 produced by surface fermentation, the major acetic acid bacteria accounted for 33% of the total bacterial cells.

[0056] 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 contaminants other than the bacteria (such as parts of fruit) 3 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. The inventors also checked images of other Examples and found similar trends to those shown in FIG. 1. Thus, the cloudy vinegars of the Examples 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.

[0057] [Evaluation of dry weight of solid content] 1 mL of each of the nigori vinegar samples from Examples 1 to 9 and Comparative Examples 1 to 3 was collected and evaporated to dryness in a hot water bath, and then dried by placing it in a dry heat thermostatic chamber at 105°C for 2 hours and 30 minutes. The weight of the dried sample 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) / Volume of sample before drying (mL) × 100

[0058] As shown in Table 1, the dry weights of the cloudy vinegars of Examples 1 to 9 were all 5% (w / v) or more and 18% (w / v) or less. On the other hand, the dry weights of the samples of Comparative Examples 1 and 3 were all less than 5% (w / v). The dry weight of the sample of Comparative Example 2 was greater than 18% (w / v).

[0059] [Evaluation of wet weight of acetic acid bacteria cells] 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 minutes), the supernatant was removed and the weight of the resulting precipitate was recorded as the wet weight.

[0060] 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).

[0061] [Evaluation of fermented sensation] The cloudy vinegars of Examples 1 to 9 and Comparative Examples 1 to 3 were put in the mouths of several trained panelists, and the rich fermented sensation derived from the bacteria was evaluated based on the evaluation criteria shown below. "Rich fermented sensation derived from the bacteria" was evaluated as the fragrant, distinctive rich flavor of the acetic acid bacteria, other than the aroma derived from the raw materials such as fruit juice or grains. Each of the cloudy vinegars of Examples 1 to 9 and Comparative Examples 1 to 3 was scored from 1 to 4 in increments of 0.5, and the average score was calculated. An average score of 2.0 or more was considered to be a pass. The results are shown in Table 1. (Evaluation criteria for the rich fermented sensation derived from the bacteria) 1: The rich fermented sensation derived from the acetic acid bacteria was weakly or not perceived 2: The rich fermented sensation derived from the acetic acid bacteria was perceived 3: The rich fermented sensation derived from the acetic acid bacteria was fully perceived 4: The rich fermented sensation derived from the acetic acid bacteria was strongly perceived

[0062] As shown in Table 1, the cloudy vinegars of Examples 1 to 9 all had a fermented feeling rating of 2.0 points or more. On the other hand, the cloudy vinegars of Comparative Examples 1 to 3 all had a fermented feeling rating of less than 2.0 points. This indicates that in cloudy vinegars containing acetic acid bacteria with an acidity of 4% or more, the number of acetic acid bacteria cells was 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 feeling derived from acetic acid bacteria can be felt.

[0063] Furthermore, the results of the groups of Examples 2, 3, and 4, and the groups of Examples 6, 7, and 8, which used the same manufacturing method but changed the bacterial species, showed that even when the bacterial species of 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 ranges. 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 examples with a high number of acetic acid bacteria cells (Examples 4 and 8) tended to have a slightly lower fermented feeling rating. This suggests that optimizing the number of acetic acid bacteria cells can suppress unpleasant flavors and enhance the fermented feeling derived from acetic acid bacteria.

[0064] Furthermore, the results of Examples 1 and 6 showed that even when the wet weight was less than 1.0% (w / v), a cloudy vinegar with a sufficiently high number of acetic acid bacteria cells and a sufficiently high fermented feel could be obtained.

[0065] Test Example 2: Investigation of Acidity of Cloudy Vinegar Production of Cloudy Vinegar Cloudy vinegars of Examples 10 to 12 were produced in the same manner as in Example 2, except that in Examples 10 and 12, the acetic acid concentration of the medium at the start of culture was 2.5%, and aerobic fermentation was performed to a final acidity of the medium of 6.5% (see Table 2), and in Example 11, the acetic acid concentration of the medium at the start of culture was 4.5%, and aerobic fermentation was performed until the final acidity reached 8.5% (see Table 2). In Examples 10 and 11, the same acetic acid bacterium Gluconacetobacter hansenii as in Examples 1 to 5 was used. In Example 12, the same acetic acid bacterium Acetobacter pasteurianus as in Example 6 was used. Acidity was measured in the same manner as in Test Example 1.

[0066]

[0067] [Evaluation of bacterial cell count] As in Test Example 1, the bacterial cell count of each of the cloudy vinegars of Examples 10 to 12 was measured. As shown in Table 2, the bacterial cell count of each of the cloudy vinegars of Examples 10 to 12 was 1.0 × 10 ８ The number was more than 1 / mL.

[0068] [Evaluation of the proportion of major acetic acid bacteria] As in Test Example 1, the proportion of major acetic acid bacteria in each of the cloudy vinegars of Examples 10 to 12 was measured, and in all cases the major acetic acid bacteria accounted for 100% of the total bacterial cells.

[0069] [Evaluation of dry weight of solids] As in Test Example 1, the dry weight of the solids 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.

[0070] [Evaluation of wet weight of acetic acid bacteria cells] 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, and the wet weight of acetic acid bacteria in Examples 10 and 11 was less than 1% (w / v).

[0071] [Evaluation of Fermented Feeling] As in Test Example 1, the fermented feel of each of the cloudy vinegars of Examples 10 to 12 was evaluated, and all of them received a score of 2.0 or higher. Of these, Examples 10 and 12, which had an acidity of 6.5%, received a higher score for fermented feel than Example 11, which had an acidity of 8.5%, and a lower score for fermented feel than Example 2, which had an acidity of 4.5%. This result showed that the fermented feel tended to decrease as the acidity increased.

[0072] <Summary> From the above, in cloudy vinegar containing acetic acid bacteria and having an acidity of 4% to 9%, the number of acetic acid bacteria was 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 unpleasant flavors were suppressed and the rich fermented taste derived from the acetic acid bacteria could be felt.

[0073] 1a, 1b... acetic acid bacteria 2... yeast 3... impurities

Claims

1. Cloudy vinegar containing acetic acid bacteria and having an acidity of 4% to 9% inclusive, wherein the main acetic acid bacteria that account for 90% or more of the bacterial cells contained in the cloudy vinegar is one species of acetic acid bacteria selected from the genera Gluconoacetobacter, Acetobacter, Gluconobacter, Komagataebacter, and Nobuacetimonas, and the number of bacterial cells of the acetic acid bacteria is 1.0 x 10 ８ 1. The cloudy vinegar characterized by having a dry weight of solids of 5% (w / v) or more and 18% (w / v) or less.

2. The cloudy vinegar according to claim 1, further containing fruit juice.

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

4. A method for producing cloudy vinegar containing acetic acid bacteria and having an acidity of 4% to 9%, comprising an acetic acid fermentation step of carrying out acetic acid fermentation in a medium containing the acetic acid bacteria previously grown, wherein the main acetic acid bacteria accounting for 90% or more of the bacterial cells contained in the cloudy vinegar is one species of acetic acid bacteria selected from the genus Gluconoacetobacter, Acetobacter, Gluconobacter, Komagataebacter, and Nobuacetimonas, and the bacterial cell count of the acetic acid bacteria is 1.0 x 10 ８ and the dry weight of the solid content is 5% (w / v) or more and 18% (w / v) or less.

5. The medium contains 1 x 10 ７ The method for producing cloudy vinegar according to claim 4, characterized in that it contains more than 1000 pieces / mL.

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

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

8. A food composition containing cloudy vinegar containing acetic acid bacteria and having an acidity of 4% to 9%, wherein the main acetic acid bacteria that account for 90% or more of the bacterial cells contained in the cloudy vinegar is one species of acetic acid bacteria selected from the genera Gluconoacetobacter, Acetobacter, Gluconobacter, Komagataebacter, and Nobuacetimonas, and the number of bacterial cells of the acetic acid bacteria in the cloudy vinegar is 1.0 x 10 ８ The food composition is characterized in that the dry weight of the solid content in the cloudy vinegar is 5% (w / v) or more and 18% (w / v) or less.

Images