• 한국식생활문화학회지
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• 제34권2호
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• pp.208-216
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• 2019

Leuconostoc spp. are generally utilized as kimchi starters, because these strains are expected to have beneficial effects on kimchi fermentation, including improvement of sensory characteristics. Here, we developed a detection method for verifying the presence of the kimchi starter Leuconostoc mesenteroides WiKim33, which is used for control of kimchi fermentation. A primer set for multiplex polymerase chain reaction was designed based on the nucleotide sequence of the plasmids in strain WiKim33, and their specificity was validated against 45 different strains of Leuconostoc spp. and 30 other strains. Furthermore, the starter strain consistently tested positive, regardless of the presence of other bacterial species in starter kimchi during the fermentation period. Our findings showed that application of a strain-specific primer set for strain WiKim33 presented a rapid, sensitive, and specific method for detection of this kimchi starter strain during natural kimchi fermentation.

• 환경생물
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• 제39권4호
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• pp.515-522
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• 2021

Jeotgal is a salty and fermented traditional Korean fish sauce. Unlike most other previous studies that investigated samples purchased from retail markets, this study focused on samples of jeotgal with traceable history to Yeonggwang, a timehonored fishing village in Korea. Three jeotgal samples, which were made from small yellow croakers, largehead hairtail, and miscellaneous fish, were selected based on information obtained from interviews with local craftsmen and literature reviews. Bacterial community profiles of the three jeotgal samples were investigated to identify indicator (and potentially core) bacteria for jeotgal ripening. The 16S rRNA gene-based metagenomic analysis revealed that the dominant phyla and classes, (Gammaproteobacteria, Betaproteobacteria, Bacilli, and Clostridia) of the three different jeotgal were identical, albeit with different composition ratios. Diversification was evident beginning at the order level. Interestingly, each dominant order was mainly comprised of single members even at the genus level. The dominant genera included Halomonas, Tetragenococcus, Halanaerobium, Pseudomonas, Massilia, and Lentibacillus. This observed genus-level heterogeneity suggests that there are diverse bacterial signatures in jeotgal and that these can be used as indicators for jeotgal ripening and/or as starters to increase its sensory quality and functionality.

• Journal of Microbiology and Biotechnology
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• 제33권6호
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• pp.780-787
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• 2023

Two mannitol producing lactic acid bacteria were isolated from pa (green onion)- kimchi, identified and named as Leuconostoc mesenteroides SKP 88 and Leuconostoc citreum SKP 92, respectively. Both isolates grew well at 25-30℃, initial pH 6-8, and 3% and lower NaCl concentration. Both isolates converted fructose into mannitol efficiently when grown on MRS broth containing fructose and glucose. Glucose was used as a carbon source and fructose was used as a precursor for mannitol. Mannitol yields were the highest in MRS broth with 3% fructose and 2% glucose. Shine muscat juice fermentation was done using each isolate as a starter. As fermentation progressed, decrease in pH and increases in titratable acidity and viable counts were observed. L. mesenteroides SKP 88 showed better mannitol conversion ability than L. citreum SKP 92, and shine muscat juice fermented with L. mesenteroides SKP 88 showed the mannitol production of 41.6 g/l at 48 h, and juice fermented with L. citreum SKP 92 showed 23.4 g/l at the same time. Yogurt fermentations showed similar patterns, and yogurt fermented with L. mesenteroides SKP 88 showed the mannitol production of 15.13 g/l. These results showed that both strains are useful as starters for healthy fermented foods with reduced fructose contents.

• 식품보건융합연구
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• 제9권6호
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• pp.9-19
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• 2023

Lactobacillus plantarum and Leuconostoc mesenteroides are crucial functional starters and predominant isolates in a wide range of fermented foods, particularly kimchi, whose constituents exhibit bioactive properties. We previously developed a methodology using anion exchange resins to purify peptidyl compounds from Lb. plantarum LBP-K10. Antibacterial cultures of Lb. plantarum LBP-K10 were obtained from the respective cultures' supernatants and filtrates. However, conclusive evidence of the efficacy of kimchi filtrates in eradicating pathogenic bacteria is lacking. We aimed to simulate the potential effects of antibacterial filtrates that contained antibacterial compounds which were derived from cultures of Lb. plantarum LBP-K10. We acquired the kimchi filtrates using a combination of centrifugation and filtration methodologies, without the requirement for inoculation. The filtered liquid from Chinese cabbage kimchi, inoculated with Lb. plantarum LBP-K10 as a starter culture, and the non-inoculated liquid from Chinese cabbage kimchi (referred to as CCK and CCKRef, respectively) were were examined. CCK demonstrated greater inhibitory activity and a more significant bactericidal effect against the bacterial indicator strains. The minimum inhibitory concentration demonstrated comparable outcomes in tests against both Gram-positive and Gram-negative bacteria. This research offers a groundbreaking examination that displays the effectiveness of profiling peptidyl compounds within kimchi filtrates for curing bacterial infections.

• 무역학회지
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• 제45권5호
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• pp.1-22
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• 2020

This study explores the role of relationship banking for the exports of SMEs (small and medium sized enterprises) in Korea. Using a sample of SMEs listed on the Korean stock markets between 2004 and 2018, I find that relationship banking has a positive impact on exporting behaviors of SMEs. This result indicates that relationship banking is suitable for SMEs to raise their funds in the export decision-making since the incentive for banks to obtain soft information enhances SMEs' access to external finance. In particular, through further analysis considering financial constraints, I find that the positive impact of relationship banking on exports is amplified for financially constrained SMEs. In addition, the positive impact on exports is also amplified for export starters. Finally, relationship banking provides benefits for SMEs' export decision-making regardless of the financial crisis. To sum up, relationship banking may be useful means of financing for Korean SMEs whose creditworthiness cannot be assessed only by hard information. As the role of finance in international trade has recently been highlighted, this study provides insightful evidence that relationship banking may enhance exports of SMEs as a source of trade finance.

• 한국축산식품학회지
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• 제36권3호
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• pp.427-434
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• 2016

Benzoic acid is occasionally used as a raw material supplement in food products and is sometimes generated during the fermentation process. In this study, the production of naturally occurring yogurt preservatives was investigated for various starter cultures and incubation temperatures, and considered food regulations. Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium infantis, and Bifidobacterium breve were used as yogurt starter cultures in commercial starters. Among these strains, L. rhamnosus and L. paracasei showed the highest production of benzoic acid. Therefore, the use of L. rhamnosus, L. paracasei, S. thermophilus, and different incubation temperatures were examined to optimize benzoic acid production. Response surface methodology (RSM) based on a central composite design was performed for various incubation temperatures (35-44℃) and starter culture inoculum ratios (0-0.04%) in a commercial range of dairy fermentation processes. The optimum conditions were 0.04% L. rhamnosus, 0.01% L. paracasei, 0.02% S. thermophilus, and 38.12℃, and the predicted and estimated concentrations of benzoic acid were 13.31 and 13.94 mg/kg, respectively. These conditions maximized naturally occurring benzoic acid production during the yogurt fermentation process, and the observed production levels satisfied regulatory guidelines for benzoic acid in dairy products.

• Journal of Microbiology and Biotechnology
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• 제12권4호
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• pp.649-656
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• 2002

Fibrinolytic microorganisms were screened from 42 samples of Korean fermented food (7 kinds of Chungook-jang, 14 kinds of commercial Doen-Jang, 5 kinds of home-made Doen-jang, and 16 kinds of Jeot-gal), 15 samples of Japanese fermented food (5 kinds of home-made soybean paste, and 10 kinds of Natto), and 19 samples of Indonesian fermented food (Tempe) as well as starters of Meju (500 microflora from Korea, and 22 from China). Initially, 11 isolates with strong fibrinolytic activity were selected for further characterization. The fibrinolytic activity of the 11 isolates ranged from 89 to 199% of standard plasmin. Four strains, M5l from Korean fermented food (Meju), I 1-1, I 1-4, and I 5-1 from Indonesian fermented food (Tempe), were chosen based on the degree of activity and reproducibility, and identified as Staphylococcus sciuri, Citrobacter or Enterobacter, Enterococcus faecalis, and Bacillus subtilis, respectively. The first two isolates are pathogenic stains while the latter two are considered as GRAS (Generally Recognized As Safe). Fibrinolytic activity of E. faecalis, characterized and designated as BRCA-5, reached a maximum, when the producer was cultivated in Ml7 broth supplemented with 1.0% glucose for 5 h at 37$^{\circ}C$ with shaking at 180 rpm. Compared to commercial fibrinolytic enzymes, the cell-free culture supernatant of 5. faecaiis BRCA-5 showed stronger activity than plasmin and streptokinase, but similar degree of specific activity as nattokinase and urokinase, aud it also demonstrated anticoagulant and antiplatelet activity ex vivo. These features of E. faecalis make it an attractive agent as a biomaterial for health-promoting foods.

• 한국수산과학회지
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• 제36권4호
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• pp.327-332
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• 2003

We Isolated strains of Micrococcus sp., Pseudomonas sp., Leuconostoc sp. which have protease activity in the Changran-Jeotgal. These microbes were added in the Changran-Jeotgal for the starters during fermentation to short fermentation period to check PH, VBN, $NH_2-N,$ free amino acids, and sensory evaluation. Microbiological changes were also examined for microorganism-added Changran-Jeotgal and the control. Viable cell counts in the microorganism-added Changran-Jeotgal increased from $7.1\times10^5\;CFU/g\;to\;7.5\times10^8\;CFU/g$ on 15th day, The cell counts in the control increased from $4.1\times10^5\;CFU/g\;to\;8.1\times10^8\;CFU/g$ on 30th day. VBN also increased in both. Increasing rates of $NH_2-N$ and free amino acids in the microorganism-added Changran-Jeotgal were faster than those in the control. Sensory evaluation showed that the microorganism-added Changran-Jeotgal was most favorable on 20th day. These results showed that fermentation period was shortened about 10 days in comparison with the control.

• 한국미생물·생명공학회지
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• 제44권3호
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• pp.303-310
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• 2016

In this study, doenjang samples were prepared with different types of salts (12%, w/w): purified salt (PS), 3-year aged solar salt (SS3), 1-year aged solar salt (SS1), and bamboo salt melted 3 times (BS). Whole-soybean mejus were fermented with starters consisting of 2 Bacillus strains, a yeast, and a fungus (starter doenjang), and control mejus were fermented with organisms present naturally in rice straw (non-starter doenjang). The whole-soybean mejus were dried, and then mixed with cooked soybeans and the respective salts. The doenjang samples were fermented for 13 weeks at 25℃. The protease (acid, neutral, and alkaline) activities, fibrinolytic activities, and antioxidant capacities of the samples were examined every week. BS doenjang showed the highest acid protease (6.46 ± 0.20 unit/g) and fibrinolytic activities (0.61 unit/ml). Among the starter doenjang samples, those made with SS and BS showed the highest total phenolic contents after 91 days of fermentation. For antioxidant activities, SS3 doenjang showed higher activities than the other doenjang samples, as evaluated by ABTS, DPPH, and FRAP assays. These results suggest that solar salt, especially aged for 3 years, is better than purified salt in terms of producing better functionalities of doenjang.

• Journal of Microbiology and Biotechnology
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• 제26권9호
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• pp.1533-1541
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• 2016

Samples of doenjang (a fermented soybean paste) were prepared with different types of salts; purified salt (PS), 3-year-aged solar salt (SS3), 1-year-aged solar salt (SS1), and bamboo salt (BS, 3^rd processing product). For starter doenjang samples, selected starters comprising two bacilli, one yeast, and one fungus were inoculated, whereas for non-starter doenjang samples, microorganisms present in rice straw were inoculated after enrichment. The doenjang samples were fermented for 13 weeks at 25℃. During the fermentation period, SS and BS doenjang samples showed higher bacilli counts as well as much lower yeast counts than PS doenjang. At 13 weeks, yeast counts of starter doenjang samples were 7.75, 5.69, 6.08, and 4.74 log CFU/g for PS, SS3, SS1, and BS doenjang, respectively. For non-starter doenjang samples, counts were 7.17, 5.05, 5.92, and 4.54 log CFU/g for PS, SS3, SS1, and BS doenjang, respectively. SS and BS promoted growth of bacilli but inhibited growth of yeasts compared with PS. Debaryomyces hansenii was the dominant yeast in PS doenjang, whereas Candida guilliermondii and Pichia sorbitophila were dominant in SS and BS doenjang. In the sensory evaluation, SS and BS doenjang scored better than PS doenjang. In conclusion, SS and BS seem better than PS for production of high-quality doenjang.