Method for producing fermented pickles

Abstract

To provide a production method of fermented pickles capable of stably producing nice-flavor fermented pickles by clarifying relations among a fermentation condition, ingredient composition, flavor, etc. of the fermented pickles.SOLUTION: A production method of fermented pickles according to the present invention includes: adding lactic acid bacteria of genus Lactobacillus to vegetable raw materials, the lactic acid bacteria, for example, Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillus diolivorans, Lactobacillus parafarraginis, Lactobacillus plantarum, Lactobacillus buchneri and Lactobacillus paraphilia; fermenting them until reached pH becomes 4.5 or less; and acquiring fermented pickles containing at least any of a succinic acid content and an isothiocyanate content more than those of vegetable raw materials.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for producing fermented pickles.

Background Art

[0002] Fermented foods are increasing in value as traditional foods and are expected to promote health, and pickles are widely recognized as fermented vegetable foods. Most of the pickle products are non-fermented light pickles. However, fermented pickles in each region still maintain a high popularity as traditional foods. Furthermore, in 2019, the "Fermented Pickle Certification System" was launched by the All Japan Pickle Cooperative Federation. From such industry trends, there is an increasing trend to return from light pickles to fermented pickles, and it is expected that future demand will grow. However, pickles have a deep negative image of being a cause of excessive salt intake, and it is necessary to eliminate this for future pickle demand. From these facts, it is considered that there may be a potential demand for salt-free (extremely low-salt) pickles among fermented pickles.

[0003] The only salt-free fermented pickle commercially produced in Japan is the traditional "Sunki" of the Koshi region made using red turnip leaves. Various lactic acid bacteria inhabit Sunki. Patent Document 1 describes that starter lactic acid bacteria including Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus delbrueckii, and Lactobacillus parabuchneri can stably produce Sunki with good quality.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the relationship between lactic acid bacteria inhabiting salt-free and extremely low-salt fermented pickles, their component composition, flavor, and other qualities has not been known until now.

[0007] An object of the present invention is to clarify the relationship between the fermentation conditions, component composition, flavor, and other qualities of fermented pickles, and to provide a method for producing fermented pickles with a good flavor that can be stably produced.

Means for Solving the Problems

[0008] The present invention provides the following. 〔1〕A method for producing a fermented pickle, comprising adding lactic acid bacteria to a vegetable raw material and fermenting until the reached pH becomes 4.5 or less to obtain a fermented pickle in which at least one of the succinic acid content and the isothiocyanate content is more than that of the vegetable raw material. 〔2〕The method according to 〔1〕, wherein the lactic acid bacteria are lactic acid bacteria belonging to the genus Lactobacillus. 〔3〕The method according to 〔1〕 or 〔2〕, wherein the lactic acid bacteria are at least one selected from Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillus diolivorans, Lactobacillus paraplantarum, Lactobacillus plantarum, Lactobacillus buchneri, Lactobacillus parakefiri, Lactobacillus crispatus, Lactobacillus gasseri, and Lactobacillus reuteri. 〔4〕The method according to 〔1〕or 〔2〕, wherein the lactic acid bacteria is a combination of Lactobacillus delbrueckii and at least one selected from Lactobacillus fermentum, Lactobacillus diolivorans, Lactobacillus parafarraginis, Lactobacillus buchneri, Lactobacillus parakefiri, Lactobacillus crispatus, and Lactobacillus gasseri. 〔5〕The method according to any one of 〔1〕to 〔4〕, wherein a first lactic acid bacteria is added to a vegetable raw material for fermentation, and then a second lactic acid bacteria is added for fermentation until the reaching pH becomes 4.3 or less. 〔6〕The method according to 〔5〕, wherein the first lactic acid bacteria is Lactobacillus delbrueckii, and the second lactic acid bacteria are Lactobacillus fermentum and Lactobacillus plantarum. 〔7〕The method according to any one of 〔1〕to 〔6〕, wherein the fermentation is carried out under temperature conditions of 30 to 45 °C. 〔8〕The method according to any one of 〔1〕to 〔7〕, wherein when fermenting, less than 2% (w / v) of sodium chloride is added to the fermentation medium. 〔9〕The method according to any one of 〔1〕to 〔8〕, wherein malic acid or its salt is added when fermenting. 〔10〕The method according to any one of 〔1〕to 〔9〕, wherein the vegetable raw material is at least one selected from turnip, cabbage, Chinese cabbage, and cucumber.

Advantages of the Invention

[0009] According to the present invention, there is provided a method for producing a fermented pickled vegetable that can be stably produced with a good flavor.

Brief Description of the Drawings

[0010]

Figure 1

Modes for Carrying Out the Invention

[0011] [Method for Producing Fermented Pickled Vegetable] In the present invention, lactic acid bacteria are added to a vegetable raw material and fermented to produce a fermented pickled product.

[0012] - Vegetable raw material - In this specification, the vegetable raw material is a raw material containing at least one kind of vegetable. Examples of vegetables include turnips (e.g., white turnips, red turnips (e.g., Otagi turnips, Kaiten turnips)), cabbages, Chinese cabbages, and cucumbers. The vegetable raw material may contain other additives such as seasonings and preservatives as needed (for example, for the purpose of preventing over-fermentation, seasoning, etc.).

[0013] - Lactic acid bacteria - In the present invention, the vegetable raw material is fermented by adding (inoculating) lactic acid bacteria as a starter to the vegetable raw material. Examples of lactic acid bacteria include lactic acid bacteria belonging to the genus Lactobacillus, Lactococcus, Leuconostoc, and Pediococcus, and lactic acid bacteria belonging to the genus Lactobacillus are preferred. Examples of lactic acid bacteria belonging to the genus Lactobacillus include L. delbrueckii, L. fermentum, L. diolivorans, L. parafarraginis, L. plantarum, L. brevis, L. vilidescens, L. alimentarius, L. sakei, L. curvatus, L. casei, L. buchneri, L. parakefiri, L. reuteri, L. crispatus, L. gasseri, L. vaginalis, L. rossiae, L. otakiensis, L. kisonensis, L. crispatus, and L. delbrueckii, L. fermentum, L. diolivorans, L. parafarraginis, L. plantarum, L. buchneri, L. parakefiri, L. crispatus, L. gasseri, L. reuteri are preferred. Examples of lactic acid bacteria belonging to the genus Pediococcus include P. acidilactici.

[0014] The lactic acid bacteria may be used alone or in combinations of two or more. When used alone, L. delbrueckii, L. fermentum, L. diolivorans, and L. parafarraginis, L. reuteri are preferred, and L. delbrueckii, L. fermentum, L. diolivorans are more preferred. When used in combinations of two or more, combinations containing at least L. delbrueckii are preferred, combinations of L. delbrueckii and at least one selected from L. fermentum, L. diolivorans, L. parafarraginis, L. buchneri, L. parakefiri, L. crispatus, L. gasseri are more preferred, and combinations of L. delbrueckii and at least one selected from L. fermentum and L. parafarraginis are even more preferred.

[0015] -Reached pH- The pH at the end of fermentation (reached pH) may be lower than the initial pH (usually weakly acidic, i.e., 5.0 - 6.0), preferably 4.5 or lower, more preferably 4.4 or lower, even more preferably 4.3 or lower. The adjustment of the reached pH may be carried out according to the fermentation conditions such as the type, amount, temperature, salt concentration, etc. of the lactic acid bacteria used. The lower limit of the reached pH is usually 3.3 or higher, preferably 3.4 or higher, but is not particularly limited.

[0016] -Fermentation temperature- The fermentation temperature is preferably 30 - 45°C, more preferably 30 - 40°C. Thereby, the reached pH can be reduced to a preferable numerical value.

[0017] -Multi-stage fermentation- When using two or more lactic acid bacteria, the lactic acid bacteria can be added simultaneously for fermentation, or alternatively, a so-called multi-stage fermentation can be carried out by adding them sequentially. For example, after adding the first lactic acid bacteria to the vegetable raw material for fermentation, the operation of adding other lactic acid bacteria for fermentation can be repeated, and finally, the last lactic acid bacteria can be added for fermentation until the reached pH becomes 4.3 or lower. The multi-stage fermentation is preferably a two-stage fermentation. After the first fermentation using L. delbrueckii as the first lactic acid bacteria, it is more preferable to carry out the second fermentation using L. fermentum and L. plantarum as the second lactic acid bacteria. The fermentation conditions for each lactic acid bacteria used in the multi-stage fermentation can be determined independently.

[0018] -Salt concentration- In fermentation, sodium chloride may be added, and the addition amount is preferably less than 2% (w / v) with respect to the medium, more preferably 1.5% (w / v) or less. Thereby, the negative image of causing excessive salt intake can be wiped out, and a very low-salt fermented pickle with improved flavor while considering health can be obtained. The addition time of sodium chloride may be during the fermentation, but the start of fermentation (in the case of multi-stage fermentation, the start of the first fermentation) is preferable.

[0019] -Malic acid- In fermentation, malic acid or its salt may be added. Thereby, a fermented pickle containing a larger amount of succinic acid can be obtained. The addition amount of malic acid is usually 50 mM or more, preferably 70 mM or more, more preferably 90 mM or more with respect to the medium. The addition time of malic acid or its salt may be during the fermentation, but the start of fermentation (in the case of multi-stage fermentation, the start of the first fermentation) is preferable.

[0020] -Other fermentation conditions- Other fermentation conditions other than the above are not particularly limited, but an example is as follows. The inoculation amount of lactic acid bacteria is usually 1.0×10 5 ~1.0×10 10 cfu / mL, preferably 5.0×10 5 ~5.0×109 cfu / mL, more preferably 1.0×10 6 ~1.0×10 9 cfu / mL. The inoculum amount can be adjusted according to conventional methods such as preculture. The fermentation time is usually 12 hours or more, preferably 20 hours or more, more preferably 24 hours or more. The upper limit is not particularly limited, but about 5 days is sufficient, usually within 3 days, and a short period is preferable from the viewpoint of hygiene. When oxygen-sensitive lactic acid bacteria such as L. delbrueckii, L. fermentum, and L. reuteri are used as the lactic acid bacteria, it is preferable to carry out the fermentation under anaerobic conditions. During fermentation, the medium may be allowed to stand or stirred as necessary.

[0021] [Fermented pickles] A fermented pickle can be obtained by the above production method. In the present specification, the "fermented pickle" means a pickle produced by a method including a step of fermenting a food material (for example, a vegetable raw material) (for example, lactic acid fermentation). For example, sunki, suguki, fermented kimchi, fermented shiba pickles, yuzukosui pickles, zukemiso, and pickles are exemplified.

[0022] The fermented pickle preferably has at least one of its succinic acid content and isothiocyanate content higher than that of the vegetable raw material, usually 4 times or more, preferably 5 times or more. Since the succinic acid content and isothiocyanate content of the fermented pickle vary depending on the vegetable raw material, it is difficult to specify uniformly, but they are usually 0.5 mM or more, preferably 5 mM or more, more preferably 6 mM or more. Isothiocyanate is a decomposition product of glucosinolate, a component peculiar to cruciferous vegetables, and is contained in cruciferous vegetables (for example, white turnip, red turnip, cabbage, Chinese cabbage). In the present specification, the isothiocyanate content means the total amount of isothiocyanates (for example, 4-pentenyl ITC, 3-butenyl ITC, 2-phenethyl ITC, allyl ITC), and is usually 8 or more, preferably 10 or more, as a relative amount to unfermented vegetables. The adjustment of the succinic acid content and isothiocyanate content can be carried out according to the type of vegetable raw material, the type, amount, and fermentation conditions of the lactic acid bacteria.

[0023] The fermented pickles preferably have a higher acid content other than succinic acid than the vegetable raw materials. Examples of the acids other than succinic acid include acetic acid and lactic acid. Since these acid contents of the fermented pickles vary depending on the vegetable raw materials, it is difficult to specify them uniformly. For example, the acetic acid content is usually 5 mM or more, preferably 6 mM or more. The lactic acid content is usually 10 mM or more, preferably 12 mM or more.

Example

[0024] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

[0025] Reference Example 1 The component compositions and the like of 49 samples exhibited at a tasting session of "Sunki", a salt-free fermented pickle that is the only one manufactured in the country, were compared to clarify the characteristics of the best product (Table 1). · The pH is 4.1, and it is fermenting well with lactic acid even when compared with the average value (4.0). · The content of succinic acid is remarkably large among the 49 samples (a contributing component to umami). · The contents of lactic acid, acetic acid, glutamic acid, and isothiocyanate (ITC) are large (contributing components to flavor and pickle aroma). · The contents of ethanol, ethyl acetate, acetoin, and diacetyl are small (causing components of fermentation odor and stuffiness odor).

[0026]

Table 1

[0027] From the results of this reference example, it became clear that the contents of succinic acid and isothiocyanate are important for high-quality salt-free fermented pickles. In addition, since all of the other characteristic components are components having taste and aroma, it is considered that they contribute complexly to a good flavor.

[0028] Example 1 Search for lactic acid bacteria strains related to the component composition of high-quality Sunki Among the lactic acid bacteria that inhabit pickled turnips, those involved in high succinic acid production were explored. 250 lactic acid bacteria colonies belonging to 18 different lactic acid bacteria species were collected from commercially available and home-made pickled turnips. Lactic acid bacteria cultured at 30 °C for 24 hours in Lactobacillus MRS medium (manufactured by Difco) were inoculated into an extract prepared by hot water extraction from the leaves of freeze-dried red turnips (Kaiten turnips), and fermentation was carried out at 30 °C for 3 days. The concentrations of water-soluble components and volatile components produced after fermentation were analyzed by nuclear magnetic resonance (NMR) method and solid-phase microextraction-gas chromatography / mass spectrometry (SPME-GC / MS) method.

[0029]

Table 2

[0030] As a result of the analysis, it was revealed that the one that produces the most succinic acid is L. delbrueckii (Table 2, Figure 1). Furthermore, the juice of turnips fermented by L. delbrueckii was closest to the characteristics of the best product shown in Reference Example 1. That is, it showed a good decrease in pH, was excellent in the content of lactic acid and acetic acid, had a small production amount of ethanol, acetoin, and ethyl acetate, and showed characteristics such as a large signal intensity of isothiocyanates. As lactic acid bacteria that showed a medium level of succinic acid production, L. fermentum, L. parafarraginis, L. reuteri, and L. diolivorans were also selected. These lactic acid bacteria are also excellent in the production amount of acetic acid. However, since the final pH of the fermented product became higher compared to L. delbrueckii, there is a risk that the appropriate quality cannot be maintained at the pH when used alone. In addition, in the fermentation of these strains, the characteristics of the component composition became different from those of the best pickled turnips.

[0031] Example 2 Analysis of applicability to various pickled vegetables Using white turnips, Akakabu of Kisoji (Kaiten Kabu, Otagi Kabu), cabbages, Chinese cabbages, and cucumbers, lactic acid bacteria shown in Tables 3 to 5, which were cultured in Lactobacillus MRS medium (manufactured by Difco) at 30°C for 24 hours, were inoculated into extracts obtained from the leaves of each plant in the same manner as in Example 1, and fermented at 30°C for 3 days. The composition of the water-soluble metabolites of the resulting fermented product was analyzed by NMR method, and the reaching pH was analyzed using a pH meter. The suitability for raw materials was determined in three grades (◎: particularly good, 〇: generally good, △: usable) (Tables 3 to 5).

[0032]

Table 3

[0033]

Table 4

[0034]

Table 5

[0035] As a result, lactic acid bacteria showed the ability to produce succinic acid in each vegetable. Among them, L. delbrueckii showed the best ability to produce succinic acid among all lactic acid bacteria in any vegetable. Regarding the pH of the fermented product, white turnips, Akakabu (Kaiten Kabu), Chinese cabbages, and cucumbers were particularly good, Akakabu (Otagi Kabu) was generally good, and for cabbages, although limited, a decrease in pH was observed. From this, it became clear that even when L. delbrueckii is used in other vegetables widely used for pickles, a salt-free fermented pickle with a good flavor characterized by succinic acid can be produced.

[0036] However, L. delbrueckii was inferior to other bacterial species in terms of its suitability for cabbage fermentation. Although the production amount of succinic acid was at the maximum level, the resulting pH reached around 4.5. In contrast, L. fermentum, which showed a medium level of succinic acid production in other vegetables, showed a succinic acid production amount comparable to that of L. delbrueckii in the fermentation of cabbage. Also, for L. fermentum, L. diolivorans, L. parafarraginis, etc., a metabolite production tendency similar to that of Kaieda turnip was confirmed.

[0037] Example 3: Co-fermentation test using a combination of multiple lactic acid bacteria Using white turnips, Akakabu of Kiso (Kaieda turnip, Otagitaki turnip), cabbages, Chinese cabbages, and cucumbers, the lactic acid bacteria shown in Tables 6 and 7, which were cultured in Lactobacillus MRS medium (manufactured by Difco) at 30°C for 24 hours in the extracts obtained from the leaves of each plant in the same manner as in Example 1, were inoculated and fermented at 30°C for 3 days. The composition of the water-soluble metabolites and the reached pH of the resulting fermented products were analyzed by the same method as in Example 2, and the suitability for the raw materials was determined in the same manner as in Examples 1 and 2 (Tables 6 and 7).

[0038] [Table 6]

[0039] [Table 7]

[0040] As a result of the tests, when L. delbrueckii and L. fermentum were co-fermented using cabbage, the accumulation amount of succinic acid increased (Tables 6 and 7). Furthermore, the production of lactic acid and acetic acid was also significantly improved, and the pH decrease was significantly ameliorated. Since it was improved compared to when each of these two lactic acid bacteria was used alone, a synergistic fermentation-promoting effect could be obtained by using these lactic acid bacteria in combination. There is no case where this synergistic effect has been scientifically verified, and its mechanism is not clear, but it is considered that some kind of symbiotic relationship may be established, such as L. delbrueckii subsp. bulgaricus and Streptococcus thermophilus complementing each other's lacking nutrients in yogurt fermentation.

[0041] In addition, the effect of co-fermentation was also observed in vegetables other than cabbage. For example, in the fermentation of white turnips and red turnips, an increasing effect of acetic acid was obtained with little influence on the production of succinic acid and lactic acid. This effect is not limited to L. fermentum but is the same for other lactic acid bacteria. Similarly, an increasing effect of lactic acid and acetic acid can be obtained even when L. buchneri, L. parakefiri, L. crispatus, and L. gasseri, which have relatively low succinic acid-producing ability, are used in co-fermentation.

[0042] Example 4 Effect of additional fermentation by two-stage co-fermentation Using white turnips, Akita red turnips (Kaiten turnips, Otagi turnips), cabbage, Chinese cabbage, and cucumbers, L. delbrueckii cultured in Lactobacillus MRS medium (manufactured by Difco) at 30 °C for 24 hours was inoculated into the extracts extracted from the leaves of each plant in the same manner as in Example 1, and fermentation was carried out at 30 °C for 3 days. Subsequently, the lactic acid bacteria shown in Tables 8 and 9 were further inoculated, and fermentation was carried out at 30 °C for an additional 3 days. The composition of the water-soluble metabolites of the obtained fermented product and the reached pH were analyzed, and the suitability for the raw materials was determined in the same manner as in Examples 1 and 2 (Tables 8 and 9).

[0043]

Table 8

[0044]

Table 9

[0045] The effect of co-fermentation was obtained not only when two strains were inoculated simultaneously as in Example 3, but also when fermentation was carried out in two stages (Tables 8 and 9).

[0046] In the case of raw materials such as cabbage that can accumulate succinic acid with L. delbrueckii alone but are poor in pH reduction, by performing a second-stage additional fermentation with lactic acid bacteria suitable for cabbage fermentation such as L. fermentum, acetic acid and lactic acid can be significantly increased without reducing succinic acid, and the pH can be reduced to 4.0 or less. This utilizes the property that L. delbrueckii preferentially produces succinic acid even in raw materials with low suitability, and is due to the remaining most of the carbon source being additionally fermented by other lactic acid bacteria.

[0047] In the case of raw materials such as Otagi turnip, where the pH reached is slightly high with L. delbrueckii alone, when additional fermentation is carried out with L. plantarum or the like, the accumulation amounts of acetic acid and lactic acid can be increased while maintaining a high succinic acid concentration, and the pH reduction can be assisted. This is realized based on the finding in this study that glucose, which is generally preferentially consumed by lactic acid bacteria compared to other carbon sources, tends to remain rather than be consumed in the fermentation of vegetable juice by L. delbrueckii. In addition to the remaining glucose, L. plantarum can convert citric acid that cannot be assimilated by L. delbrueckii into lactic acid and acetic acid.

[0048] Example 5 Influence of fermentation temperature Using the red turnips of Kiso (Kaiten turnip, Otagi turnip), L. delbrueckii was inoculated into the extracts extracted from the leaves of each plant in the same manner as in Example 1, and fermentation was carried out for 14 days from day 1 under the temperature conditions shown in Tables 10 and 11. After the start of cultivation, the composition of the water-soluble metabolites and the reached pH of the fermented product were analyzed by the same method as in Example 2 (Tables 10 and 11).

[0049]

Table 10

[0050]

Table 11

[0051] When the effect of temperature on the fermentation of pickles was examined, the fermentation temperature at which the pH decreased most rapidly and the reached pH was also the lowest was 40°C (Tables 10 and 11). At 30°C, it was slightly slower, and at 45°C, the fermentation was slightly delayed. At 50°C or 20°C or lower, the deterioration of pH decrease was remarkable. The production amount of succinic acid was the largest at 40°C or 30°C, and a difference similar to the progress of pH decrease was observed. Therefore, it is considered that appropriate fermentation progress can be obtained preferably in the range of 30°C to 45°C, more preferably in the range of 30°C to 40°C.

[0052] Example 6 Salt concentration tolerance of L. delbrueckii Using the red turnips (Kaiten turnips) of Kiso, L. delbrueckii was inoculated into the extracts extracted from the leaves of each plant in the same manner as in Example 1, and a quarter volume of saline was added to the concentration shown in Table 12, and fermentation was carried out at 30°C for 3 days. After the start of cultivation, the composition of the water-soluble metabolites of the fermented product and the reached pH were analyzed by the same method as in Example 2 (Table 12).

[0053]

Table 12

[0054] Fermentation was significantly suppressed at an NaCl concentration of 2% (w / v) or higher, whereas no significant effect on the composition of the metabolites was observed at an NaCl concentration of less than 2% (w / v) (Table 12). From this, it was found that salt may be added at a concentration of less than 2% (w / v).

[0055] Example 7 Enhancement of succinic acid production by the addition of malic acid Using cabbage, sodium malate (manufactured by Fujifilm Wako Pure Chemical Corporation) was added to the extracts obtained from the leaves of each plant in the same manner as in Example 1 to a concentration of 100 mM, and the lactic acid bacteria shown in Table 13, which were cultured in Lactobacillus MRS medium (manufactured by Difco) at 30°C for 24 hours, were inoculated and fermented at 30°C for 3 days. After the start of the culture, the composition of the water-soluble metabolites and the final pH of the fermented product were analyzed by the same method as in Example 2 (Table 13).

[0056]

Table 13

[0057] When co-fermentation of L. delbrueckii and L. fermentum was carried out after adding 100 mM sodium malate, the enhancing effect of succinic acid in the co-fermentation was further increased by the addition of sodium malate (Table 13). From this result, it was found that, based on the co-culture of L. delbrueckii and L. fermentum, the characterization of fermented pickles by succinic acid can be further enhanced by using sodium malate in combination.

[0058] It is considered that most of the production of succinic acid by lactic acid bacteria in the fermentation of vegetables is due to the conversion of malic acid to succinic acid. From the results of this example, it can be seen that in the case of vegetables where lactic acid bacteria such as L. delbrueckii can produce a large amount of succinic acid alone, the production of succinic acid by lactic acid bacteria can be enhanced simply by adding malic acid.

[0059] Example 8 Influence of oxygen on the progress of fermentation Using the red turnips of Kiso (Kaiten turnips, Otagi turnips), the extracts obtained from the leaves of each plant in the same manner as in Example 1 were placed in a culture tube with a two-position cap (manufactured by Corning), and the lactic acid bacteria shown in Table 14 were inoculated and fermented at 30°C for 3 days. For the anaerobic condition group, fermentation was carried out anaerobically using AnaeroPack (manufactured by Mitsubishi Gas Chemical Company) in a sealed anaerobic jar. For the group with aeration, the two-position cap was left in an aerated state and left standing in a semi-open anaerobic jar, and the medium was mixed every 24 hours to provide aeration. The water-soluble metabolites and the reached pH of the obtained fermented product were analyzed by the same method as in Example 2 (Table 14).

[0060]

Table 14

[0061] L. delbrueckii showed obvious sensitivity to oxygen (Table 14). Also, not only did the reached pH increase, but the amount of succinic acid production by L. delbrueckii also decreased significantly to about 1 / 3. L. fermentum also showed some sensitivity to oxygen, although slightly. Therefore, it was found that when using oxygen-sensitive lactic acid bacteria such as L. delbrueckii and L. fermentum, it is preferable to perform the culture under anaerobic conditions.

[0062] Example 9 Small-scale preparation test of salt-free fermented pickles In a pickled vegetable factory with experience in manufacturing fermented pickles, salt-free fermented pickles using L. delbrueckii were trial-produced and the fermented products were evaluated. As the fermentation starter, L. delbrueckii was cultured at 37°C for 24 hours using the centrifuged supernatant of salt-free tomato juice (product name: Kagome Salt-Free Tomato Juice, manufactured by Kagome Co., Ltd.) and a food-grade medium prepared with food additives (0.5% Heinute AM (manufactured by Fuji Oil Co., Ltd.), 3.0% edible yeast extract (Marmite: manufactured by Unilever), 0.5% sodium acetate, 0.02% magnesium sulfate, adjusted to pH 6.5 with sodium hydroxide and autoclaved at 115°C for 10 minutes). Using red turnips, Chinese cabbages, cucumbers and cabbages, 9 kg of each shredded raw material was blanched with 70°C hot water and then placed in plastic bags installed in a pickle container. L. delbrueckii was inoculated to a starting concentration of 1.0×10 7 cfu / mL. After expelling the air from the plastic bag so that the raw materials were immersed in the liquid surface, the bag was closed, the container was wrapped with a mattress for heat preservation and left standing at room temperature for fermentation for 3 days. As a comparative control, a non-fermented salt-free pickle pickled for 3 days with the addition of 0.5% lactic acid was prepared. The metabolites contained in the juice of the resulting pickles, the reached pH, the number of lactic acid bacteria, the number of coliform bacteria, and the number of molds and yeasts were analyzed (Table 15). In addition, the palatability of the finished salt-free fermented pickles was evaluated by 4 panelists, and each judged on a 3-point scale (3 points: particularly good, 2 points: generally good, 1 point: poor), and the average value of the scores (average evaluation) was calculated (Table 16).

[0063]

Table 15

[0064]

Table 16

[0065] In each fermented pickle, fermentation metabolites such as succinic acid were produced and good palatability was exhibited. From this, it was found that the fermentation proceeded well, and the produced succinic acid, ITC, etc. contributed to the improvement of flavors such as umami and aroma (Tables 15 and 16).

[0066] Example 10 Effects of Fermentation and Co-Fermentation by Various Lactic Acid Bacteria on ITC Content Using pickled cruciferous vegetables (white turnip, Akakabu of Kisoji (Kaiten Kabu, Otagi Kabu), cabbage, Chinese cabbage) that characteristically contain glucosinolates as substrates for ITC production, the extracts obtained from the leaves of each plant in the same manner as in Example 1 were inoculated with the lactic acid bacteria shown in Table 17 that were cultured in MRS medium for Lactobacillus (manufactured by Difco) at 30 °C for 24 hours, and fermented at 30 °C for 3 days. In addition, a fermentation test using a composite starter was also carried out. In the co-fermentation test, co-fermentation and two-stage fermentation were carried out in the same manner as in Example 3 and Example 4. In the co-fermentation test, L. delbrueckii and other lactic acid bacteria shown in Table 18 were inoculated and fermented at 30 °C for 3 days. In the two-stage fermentation test, after fermentation with L. delbrueckii at 30 °C for 3 days, fermentation was further carried out at 30 °C for 3 days using other lactic acid bacteria shown in Table 18. Fermentation was carried out using inert glass vials with screw caps. The composition of the volatile metabolites of the resulting fermented products was analyzed using SPME-GC / MS, and the peak area values shown by each ITC were compared as signal intensities (Table 17 and Table 18).

[0067] [Table 17]

[0068] [Table 18]

[0069] As a result of the analysis, it was revealed that when cruciferous pickled vegetables were fermented by L. delbrueckii, more ITCs were produced than by other lactic acid bacteria (Table 17). When white turnips, red turnips (Kaida turnips, Otagi turnips), and Chinese cabbages were used, 4-pentenyl ITC and 3-butenyl ITC increased by about 1.5 to about 2.5 times compared to the uninoculated lactic acid bacteria. Only allyl ITC was detected in cabbages, but when fermented with L. delbrueckii, the signal intensity increased slightly compared to the uninoculated lactic acid bacteria. In samples fermented by L. plantarum, extremely strong ITC signals were detected in some vegetables. This characteristic brings a strong pungency to the pickles and there is concern that it may lead to abnormal quality. From the above, it is expected that using L. delbrueckii for the fermentation of cruciferous vegetables will moderately enhance the characteristics of ITC aroma and pungency.

[0070] In the co-fermentation of L. delbrueckii and other lactic acid bacteria, the effect of increasing each ITC was obtained in many combinations such as L. diolivorans, L. parafarraginis, and L. parakefiri compared to the uninoculated lactic acid bacteria (Table 18). Therefore, it can be seen that the high production of succinic acid and ITC by L. delbrueckii and the promotion of lactic acid and acetic acid production by the co-fermentation shown in Example 3 can be achieved simultaneously.

Claims

1. A method for producing a fermented pickled vegetable, comprising adding lactic acid bacteria to a vegetable raw material and fermenting until the reached pH becomes 4.5 or less under the conditions of a fermentation temperature of 30 to 45°C and a sodium chloride addition amount of less than 2% (2 / v), to obtain a fermented pickled vegetable in which at least one of the succinic acid content and the isothiocyanate content is more than that of the vegetable raw material, wherein the vegetable raw material is cabbage, and the lactic acid bacteria are at least one selected from Lactobacillus diolivorans, Lactobacillus parafarraginis, Lactobacillus plantarum, Lactobacillus buchneri, Lactobacillus parakefir, Lactobacillus crispatus, Lactobacillus otakiensis, and Lactobacillus xylosenensis, or at least one combination selected from the group consisting of Lactobacillus delbrueckii and a combination of Lactobacillus fermentum, Lactobacillus diolivorans, Lactobacillus parafarraginis, Lactobacillus buchneri, and Lactobacillus parakefir, a method.

2. A method for producing a fermented pickled vegetable, comprising adding lactic acid bacteria to a vegetable raw material and fermenting until the reached pH becomes 4.5 or less under the conditions of a fermentation temperature of 30 to 45°C and a sodium chloride addition amount of less than 2% (2 / v), to obtain a fermented pickled vegetable in which at least one of the succinic acid content and the isothiocyanate content is more than that of the vegetable raw material, wherein the vegetable raw material is Chinese cabbage, and the lactic acid bacteria are at least one selected from Lactobacillus delbrueckii, Lactobacillus diolivorans, Lactobacillus parafarraginis, Lactobacillus plantarum, Lactobacillus buchneri, Lactobacillus parakefir, Lactobacillus otakiensis, and Lactobacillus xylosenensis, or at least one combination selected from the group consisting of Lactobacillus delbrueckii and a combination of Lactobacillus fermentum, Lactobacillus diolivorans, Lactobacillus parafarraginis, Lactobacillus buchneri, Lactobacillus parakefir, Lactobacillus crispatus, and Lactobacillus gasseri, a method.

3. Add lactic acid bacteria to the vegetable raw material and ferment it under the conditions of a fermentation temperature of 30 to 45°C and a sodium chloride addition amount of less than 2% (2 / v) until the reached pH becomes 4.5 or less, to obtain a fermented pickled product in which at least one of the succinic acid content and the isothiocyanate content is more than that of the vegetable raw material. A method for producing a fermented pickled product, The vegetable raw material is cucumber, The lactic acid bacteria are, At least one selected from Lactobacillus delbrueckii, Lactobacillus diolivorans, Lactobacillus paraplantarum, Lactobacillus plantarum, Lactobacillus buchneri, Lactobacillus parakefir, and Lactobacillus otakiensis, or, At least one combination selected from the combination of Lactobacillus delbrueckii and at least one selected from Lactobacillus fermentum, Lactobacillus diolivorans, Lactobacillus paraplantarum, Lactobacillus buchneri, Lactobacillus parakefir, Lactobacillus crispatus, and Lactobacillus gasseri, Method.

4. After adding and fermenting the first lactic acid bacteria to the vegetable raw material, add the second lactic acid bacteria and ferment it under the conditions of a fermentation temperature of 30 to 45°C and a sodium chloride addition amount of less than 2% (w / v) until the reached pH becomes 4.3 or less, to obtain a fermented pickled product in which at least one of the succinic acid content and the isothiocyanate content is more than that of the vegetable raw material. A method for producing a fermented pickled product, The vegetable raw material is turnip, cabbage, Chinese cabbage or cucumber, The first lactic acid bacteria are Lactobacillus delbrueckii, The second lactic acid bacteria are at least one selected from Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus diolivorans, Lactobacillus paraplantarum, Lactobacillus buchneri, and Lactobacillus parakefir, Method.

5. The method according to claim 4, wherein the first lactic acid bacteria are Lactobacillus delbrueckii and the second lactic acid bacteria are Lactobacillus fermentum and / or Lactobacillus plantarum.

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