Lactobacillus plantarum mingles strain having reduced capacity to produce lactic acid which causes kimchi to go rancid

Abstract

The present invention relates to a Lactobacillus plantarum mingles strain (KCTC accession number 15821BP) which has a reduced capacity to produce lactic acid, which causes kimchi to go rancid, and thus improves the storability of kimchi. The Lactobacillus plantarum mingles strain (KCTC accession number 15821BP) according to the present invention has a reduced capacity to produce lactic acid, which causes kimchi to go rancid, compared to commercially available Lactobacillus plantarum strains, and thus can improve the storability of kimchi. Therefore, when kimchi is manufactured using the strain of the present invention it is possible to maintain stable quality during the distribution process, slow down the production of lactic acid that greatly affects the taste of kimchi, and thus provide consumers with more delicious kimchi.

Description

Lactobacillus plantarum MINGLES strain with reduced lactic acid production capacity, which causes kimchi to go rancid

[0001] The present invention relates to a Lactobacillus plantarum mingles strain (accession number KCTC 15821BP), characterized in that the production capacity of lactic acid, which causes kimchi to go rancid, is reduced, thereby improving the storage property of kimchi.

[0002] Kimchi is a traditional Korean fermented food, made by fermenting and maturing ingredients like pickled cabbage, radish, and cucumber with various seasonings over a period of time. It is a major part of the Korean diet. Kimchi is made from a variety of vegetables, which harbor various microorganisms, including bacteria, molds, and yeasts, derived from the soil, air, and water. While some of these microorganisms are removed during the pickling and washing processes, salt-tolerant lactic acid bacteria remain, playing a key role in kimchi fermentation.

[0003] Changes in the lactic acid bacteria community according to the kimchi fermentation stage are important factors in determining kimchi quality. The proliferation of hetero-fermentative lactic acid bacteria, such as Leuconostoc mesenteroides, improves the sensory characteristics of kimchi, but the proliferation of homo-fermentative lactic acid bacteria after the optimal ripening period is known to lower the quality of kimchi.

[0004] Kimchi has traditionally been produced and consumed in small quantities at home. However, with the rise of the urban population due to changes in industrial structure, the development of processed foods, and the rise of group meal services, changes in dietary and cultural habits have led to a gradual increase in the supply of large-scale, packaged kimchi. Consequently, freshness is a critical factor in determining kimchi quality and marketability, and thus, the need to extend the shelf life of packaged kimchi by maintaining freshness over an extended period has emerged.

[0005] Meanwhile, gas pressure treatment has recently been proposed as a new method for sterilizing microorganisms. According to this method, tens to hundreds of atmospheres of pressure are applied to the object to be sterilized using carbon dioxide, and then the pressure is reduced to normal pressure. During the pressurization, the gas dissolved in the cells is rapidly released to the outside of the cells during the depressurization process, destroying the cells. The sterilization effect is generally 10 -5 10 inland -7 It is known to reach .

[0006] This gas pressure treatment method is a newly proposed and effective sterilization method, but it has only recently moved beyond the laboratory stage and is being applied industrially. Furthermore, due to the difficulty of determining treatment methods and conditions based on the characteristics of each sterilized object, there have been no specific reports of this sterilization method being applied to kimchi to maintain its freshness and extend its shelf life.

[0007] Therefore, in order to accelerate the commercialization of kimchi, a traditional food, there is an urgent need to develop a method to extend the storage life while maintaining the inherent quality of kimchi.

[0008] The substances that give kimchi its sour taste include various organic acids (lactic acid and acetic acid are representative), and the bacteria that produce these organic acids are lactic acid bacteria. Simply put, lactic acid bacteria is a general term for bacteria that break down sugars to produce various acids, including lactic acid. Although other bacteria also produce some lactic acid, bacteria that produce more than 50% lactic acid through fermentation under anaerobic (air-free) conditions are called lactic acid bacteria, and these lactic acid bacteria are sometimes called lactic acid bacteria.

[0009] Kimchi is a lactic acid fermented food. The lactic acid bacteria in kimchi convert the sugars in vegetables into lactic acid, giving kimchi a refreshing flavor and killing harmful bacteria.

[0010] However, after kimchi ferments, the lactic acid bacteria begin to die, unable to withstand the organic acids they themselves produced. This causes yeast and mold to begin growing again, altering the kimchi's flavor. This causes the kimchi to develop a musty odor and turn brown. Various types of lactic acid bacteria play a role in kimchi fermentation.

[0011] The lactic acid bacteria involved in the initial fermentation are Leuconostoc mesenteroides, which gives kimchi its proper flavor, and Lactobacillus plantarum, a lactic acid bacteria that appears in the middle and late stages, kills other harmful bacteria, but produces excessive acid, which causes kimchi to go rancid.

[0012] The present invention aims to provide a Lactobacillus plantarum strain having a weakened ability to produce lactic acid or acetic acid, which are causes of rancidity, in order to prevent rancidity of kimchi and extend the storage period of kimchi.

[0013] The present invention provides a Lactobacillus plantarum mingles strain (accession number KCTC 15821BP).

[0014] The above strain is characterized by a reduced ability to produce lactic acid, which causes kimchi to go rancid, thereby improving the storage properties of kimchi.

[0015] The above strain is characterized by a lactic acid production of 2.4 g / l when inoculated into 5 ml of MRS medium containing 10 g / l of glucose and cultured at 30°C for 96 hours.

[0016] When kimchi is made by adding the above strain, it is characterized by a pH of 4.4 after 60 days.

[0017] When kimchi is made by adding the above strain, the number of lactic acid bacteria reaches its maximum after 60 days.

[0018] The above strain is characterized in that, when cultured with erythorbic acid and used to make kimchi, the ripening delay effect of kimchi is improved.

[0019] According to another embodiment of the present invention, a method for producing kimchi is provided, comprising the step of producing kimchi by mixing salted vegetables for kimchi with a seasoning containing a strain according to any one of claims 1 to 5.

[0020] The Lactobacillus plantarum mingles strain (Accession No. KCTC 15821BP) of the present invention has the characteristic of improving the storage stability of kimchi by reducing the production capacity of lactic acid, which causes kimchi to go rancid, compared to commercially available Lactobacillus plantarum strains. Therefore, when kimchi is manufactured using the strain of the present invention, stable quality can be maintained during the distribution process, and the production of lactic acid, which has a significant impact on the taste of kimchi, can be slowed down, thereby providing consumers with more delicious kimchi.

[0021] When a part in this specification is said to "include" a certain component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0022]

[0023] The present invention provides a Lactobacillus plantarum mingles strain (accession number KCTC 15821BP). The strain is characterized by having a reduced ability to produce lactic acid, which causes kimchi to go rancid, thereby improving the storage properties of kimchi.

[0024] Kimchi rancidity refers to a condition in which the organic acids produced by lactic acid bacteria increase, making it unsuitable for consumption. Therefore, to improve kimchi's shelf life and shelf life, it is necessary to reduce the production of organic acids, specifically lactic acid, produced by lactic acid bacteria.

[0025] The Lactobacillus plantarum mingles strain (accession number KCTC 15821BP) provided in the present invention has a characteristic of reduced lactic acid production ability compared to general Lactobacillus plantarum strains, and when kimchi is manufactured using the strain of the present invention, the production of lactic acid, which causes rancidity of kimchi, can be reduced, thereby improving the storage and distribution properties of kimchi.

[0026] The Lactobacillus plantarum mingles strain (accession number KCTC 15821BP) of the present invention is characterized by a lactic acid production amount of 2.4 g / l when inoculated into 5 ml of MRS medium containing 10 g / l of glucose and cultured at 30°C for 96 hours. While the lactic acid production amount of a typical Lactobacillus plantarum strain is 5.3 g / l, the strain of the present invention has a lactic acid production amount of about 50% or less.

[0027] When kimchi is made by adding the above strain, it is characterized by a pH of 4.4 after 60 days.

[0028] For typical kimchi, the fermentation period is approximately 15 to 20 days, at which point the pH reaches approximately 4.3, resulting in well-ripened kimchi with a crisp, sweet-and-sour flavor. However, when kimchi was produced using the strain of the present invention, the pH reached 4.4 after 60 days, demonstrating that the strain can delay kimchi rancidity and improve its shelf life.

[0029] When kimchi is manufactured by adding the above strain, the number of lactic acid bacteria reaches its maximum after 60 days. According to the inventor's experiments, when kimchi is manufactured without adding the strain of the present invention, the number of lactic acid bacteria reaches its maximum after about 30 days, but when kimchi is manufactured using the strain of the present invention, the number of lactic acid bacteria reaches its maximum after 60 days.

[0030] The above strain is characterized by an improved ripening delay effect or rancidity delay effect when kimchi is made after being cultured with erythobic acid. Therefore, when making kimchi using the strain of the present invention, if the strain is cultured with erythobic acid and then added to the kimchi, it is expected that rancidity of the kimchi can be further delayed, and thus the storage or distribution property of the kimchi can be further improved.

[0031] According to another embodiment of the present invention, a method for producing kimchi is provided, comprising the step of producing kimchi by mixing salted vegetables for kimchi and a seasoning including the strain.

[0032] The above kimchi vegetables may vary depending on the type of kimchi to be made, and may be, for example, one or more selected from the group consisting of cabbage, radish, turnip, and radish.

[0033] It is preferable to pickle the above kimchi vegetables in brine with a salinity of 5 to 20%.

[0034] The above seasoning can be varied depending on the type of kimchi, and can be easily prepared and added by a person skilled in the art.

[0035]

[0036] The composition of the seasoning in the present invention is not limited, and for example, it may be one or more selected from the group consisting of radish, green onion, onion, red pepper powder, salt, garlic, ginger, green onion, sugar, and salted seafood. Users can appropriately select the components of the seasoning according to their taste, preference, climate, season, and other circumstances.

[0037] However, the above seasoning may include the above strain. The strain may be prepared as a live cell, a dead cell, or a culture medium. The strain may be added to the seasoning after being cultured with erythobic acid.

[0038] The above strain is 10 times higher than the total seasoning.5 ~ 10 8 Concentration of cells / g, preferably 10 6 ~ 10 7 It can be added at a concentration of cells / g, but is not limited thereto.

[0039]

[0040] Hereinafter, preferred examples are presented to aid in understanding the present invention. However, the following examples are provided solely to facilitate a better understanding of the present invention, and the scope of the present invention is not limited by the following examples.

[0041]

[0042] <Example>

[0043] 1. Isolation of strains

[0044] The entire kimchi with a pH of 0.6-0.8% was crushed and filtered through sterile gauze to use as a sample for isolating effective strains. After diluting the sample, 0.1 mL was taken and spread on MRS (Difco Laboratories, Detroit, MI, USA) agar medium supplemented with 0.01% bromocresol green and cultured at 30°C for 48 hours. Bromocresol green is a pH indicator used to identify pH values ​​between 3.8 and 5.4. Below pH 3.8, the indicator solution is yellow, and above pH 5.4, the solution is blue. Between pH 3.8 and 5.4, the indicator solution is green.

[0045] During the growth process of the strain, five strains with a green color (pH value between 3.8 and 5.4) were selected due to a low lactic acid production ability, and the colonies formed through pure culture three times on MRS plate medium were subcultured and stored at -70℃ for use in the experiment.

[0046]

[0047] 2. Investigation of kimchi fermentation characteristics of the above isolated strain (pH measurement)

[0048] In order to measure the change in pH when making kimchi by adding the above-mentioned isolated strain, kimchi was made using the above-mentioned strain.

[0049] After pickling the cabbage in 10-15% (w / v) brine for 24 hours, the cabbage was washed three times in tap water. The seasoning used in making kimchi was prepared by mixing red pepper powder, garlic, green onion, ginger, shrimp paste, anchovy sauce, sugar, and glutinous rice powder in a weight ratio of 2.5:2.5:2.5:0.5:1.7:1.3:0.5:3.5. The pickled cabbage and seasoning were mixed in a ratio of approximately 7:3, and the strain added to the kimchi was sufficiently cultured in MRS medium and added in an amount of 10 to the total seasoning. 6 ~ 10 7 Kimchi was prepared by mixing with seasoning at a concentration of 10 cells / g.

[0050] The kimchi manufactured above was stored at 5℃ for 60 days and the pH change of the kimchi was observed.

[0051] Strain 0 days 15 days 30 days 45 days 60 days 16.05.64.74.13.926.05.75.24.94.436.05.54.44.03.946.05.54.54.23.756.05.64.84.13.7Untreated 6.04.64.24.03.8

[0052] For typical kimchi, the fermentation period is approximately 15 to 20 days, at which point the pH reaches approximately 4.3, resulting in well-ripened kimchi with a crisp, sweet-and-sour flavor. The aforementioned strains 1 to 5 all exhibited a tendency for acidity to decrease slowly, indicating their ability to prevent kimchi from rancidity. However, when the storage period is prolonged, the pH of the kimchi becomes similar to that of untreated kimchi.

[0053] Among the above strains, strain 2 exhibited the highest pH and was confirmed to be most effective in preventing kimchi from becoming rancid. The inventors performed 18s rRNA identification on strain 2 and identified it as Lactobacillus plantarum.

[0054] The inventor named the strain Lactobacillus plantarum mingles and deposited it with the Korea Research Institute of Bioscience and Biotechnology on February 20, 2024 (deposit number KCTC 15821BP).

[0055]

[0056] <Experimental Example>

[0057] 1. Measurement of lactic acid production capacity of the above strain

[0058] The inventors measured the lactic acid production capacity of the strain. The strain was inoculated into 5 ml of MRS medium containing 10 g / l glucose and cultured at 30°C for 96 hours, after which lactic acid production capacity was evaluated. For comparison, a commercially available Lactobacillus plantarum strain was also tested using the same method.

[0059] Lactic acid and xylose concentrations were measured using HPLC equipped with a Rezex ROA-Organic Acid H+ (Phenomenex, USA) column (mobile phase 0.005 N sulfuric acid solution, flow rate 0.6 ml / min).

[0060] As a result of the above measurement, the lactic acid production amount of the Lactobacillus plantarum mingles strain of the present invention was 2.4 g / l, and the lactic acid production amount of the commercially sold Lactobacillus plantarum strain was 5.3 g / l.

[0061] Therefore, the lactic acid production amount of the Lactobacillus plantarum mingles strain of the present invention is lower than that of a general Lactobacillus plantarum strain, and thus exhibits the effect of improving the storage life of kimchi by reducing lactic acid, which is a cause of rancidity in kimchi.

[0062]

[0063] 2. Measuring the salinity of kimchi

[0064] The inventors of the present invention measured the salinity of the kimchi prepared in the above examples. The salinity was measured three times using the Mohr method (Doughty HW. 1924. Mohr's method for the determination of silver and halogens in other than neutral solutions. J Am Chem Soc 46: 2707-2709). Approximately 1 g of a paste-like sample ground in a blender was diluted 100-fold and filtered (Toyo No. 1). 10 mL of the filtrate was taken, 1 mL of 2% potassium chromate was added, and titrated with a 0.02 N AgNO3 solution. A blank test was separately conducted on distilled water, and the salinity was calculated according to the following mathematical formula 1.

[0065] [Mathematical Formula 1]

[0066] Salinity (%) = {(AB) x 0.00117 xfx D x 100} / S

[0067] A: mL of 0.02 N AgNO3 solution consumed in this test

[0068] B: mL of 0.02 N AgNO3 solution consumed in the background test

[0069] f: Titer of 0.02 N AgNO3 solution

[0070] D: Dilution factor

[0071] S: Sample amount (g)

[0072] 0 days 15 days 30 days 45 days 60 days KCTC 15821BP2.52.32.42.42.4 Untreated 2.52.42.32.42.4

[0073] Referring to Table 2 above, it was confirmed that the salinity of kimchi with and without the addition of the Lactobacillus plantarum mingles strain of the present invention remained generally constant. Therefore, it was confirmed that the Lactobacillus plantarum mingles strain of the present invention did not affect the salinity of kimchi.

[0074] 3. Measurement of microbial changes according to kimchi storage period

[0075] The number of lactic acid bacteria according to the storage period of kimchi treated with the Lactobacillus plantarum mingles strain of the present invention and kimchi not treated was analyzed.

[0076] After taking 10 g of kimchi sample, it was diluted 10-fold with sterilized 0.85% saline solution, homogenized with a stomacher (Bagmixer R400, Interscience, Saint Nom, France), and serially diluted to conduct the experiment. For the number of lactic acid bacteria, the serially diluted sample was inoculated into a medium prepared by adding 25 ppm of bromocresol purple (BCP, Samchun chemical, Pyeongtaek, Korea) indicator to MRS (Lactobacilli MRS agar, Difco) medium, and then cultured at 30℃ for 48 hours using the pouring culture method. The total colonies and colonies that showed yellow color reaction (organic acid producing bacteria) were counted. The number of lactic acid bacteria colonies counted was expressed as colony forming unit (log CFU / mL).

[0077] 0 days 15 days 30 days 45 days 60 days KCTC 15821 BP4.566.567.038.619.01 Untreated 3.715.868.927.536.97

[0078] Referring to the above [Table 3], in the case of the untreated control group, the number of lactic acid bacteria was the highest on the 10th day and decreased thereafter. On the other hand, in the case of kimchi treated with the Lactobacillus plantarum mingles strain of the present invention, it was confirmed that the number of lactic acid bacteria increased slowly and reached the maximum on the 60th day. This shows that the Lactobacillus plantarum mingles strain of the present invention has the effect of delaying the ripening of kimchi by delaying the maximum production period, thereby improving the storage and distribution properties of kimchi.

[0079]

[0080] 4. Kimchi fermentation characteristics according to food additives

[0081] The present inventor screened a substance that can further improve the storage and distribution properties of kimchi by reducing the fermentation of kimchi by the Lactobacillus plantarum mingles strain isolated above.

[0082] The inventor of the present invention inoculated 1% (v / v) of the Lactobacillus plantarum mingles strain of the present invention into MRS medium to which 1% (v / v) of the food additives described in Table 4 was added, cultured for 48 hours, and then kimchi was prepared using the same method as in the example, and the pH on the 60th day was measured.

[0083] Glucoamylase, mucin, erythovate, pH 4.3, 4.4, 4.8

[0084] The inventors of the present invention confirmed that there was no change in the final pH for glucoamylase and mucin, but that erythobic acid showed a pH value higher than the pH value in Table 1 when cultured with erythobic acid. Therefore, the Lactobacillus plantarum mingles strain can improve the ripening delay effect of kimchi.

[0085]

[0086] [Accession number]

[0087] Name of depositor: Korea Research Institute of Bioscience and Biotechnology, Biological Resource Center (KCTC)

[0088] Accession number: KCTC15821BP

[0089] Date of acceptance: 20240220

[0090]

[0091] [Correction pursuant to Rule 91, August 25, 2025]

Claims

1. Lactobacillus plantarum mingles strain (accession number KCTC 15821BP) characterized by reducing the production capacity of lactic acid, which causes kimchi to go rancid, thereby improving the storage life of kimchi.

2. In paragraph 1, The strain is characterized in that, when inoculated into 5 ml of MRS medium containing 10 g / l of glucose and cultured at 30°C for 96 hours, the lactic acid production amount is 2.4 g / l.

3. In paragraph 1, A strain characterized in that the pH is 4.4 after 60 days when kimchi is manufactured by adding the above strain.

4. In paragraph 1, A strain characterized in that the number of lactic acid bacteria reaches a maximum after 60 days when kimchi is made by adding the above strain.

5. In paragraph 1, The above strain is characterized in that the effect of delaying the ripening of kimchi is improved when kimchi is manufactured after being cultured with erythobic acid.

6. Vegetables for salted kimchi and A method for producing kimchi, comprising a step of producing kimchi by mixing the kimchi with a seasoning containing the strain of any one of claims 1 to 5.

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