• 한국미생물·생명공학회지
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• 제23권4호
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• pp.373-377
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• 1995

We investigated the survival, $\beta$-galactosidase activity and cellular permeability of lactic acid bacteria such as Lactobacillus acidophilus ATCC 4356, Lactobacillus casei subsp. casei IFO 3533, Streptococcus thermophilus KCTC 2185, Lactobacillus delbrueckii subsp. lactis ATCC 4797, and Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 in anaerobic condition of pH 1.5-3.5 range. Numbers of all tested viable cells did not decrease at pH 3.5, but decreased rapidly at pH 1.5 and pH 2.5 during 2 hour incubation at modified EG medium. Immediately after 2 hour incubation, the decrease in population at pH 1.5 and pH 2.5 was about 6-8 and 5-7 log cycles/ml, respectively. Lactobacillus acidophilus ATCC 4356 showed the higest survival of all tested bacteria. The $\beta$-galactosidase activity from Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 and Streptococcus thermophilus KCTC 2185 decreased rapidly at pH 1.5 and 2.5, but there was a little decrease at pH 3.5. The cellular permeability that was measured by the leakage of intracellular materials increased with decrease of pH. These results suggest that the ingested lactic acid bacteria may be destroyed in contact with low pH of gastric acid.

• 한국식품영양학회지
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• 제12권1호
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• pp.77-84
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• 1999

The purpose of this study is to establish a rapid preparation method of Dongchimi-juice having favor-able flavor and high antibacterial activity against undesirable bacteria in Naengmyon-broth by using high antibacterial strains of lactic acid bacteria Lactobacillus homohiochii B21 and leuconostoc mesenteroid-es subsp. mesenteroides C16 as Dongchimi starter. When the two strains of lactic acid bacteria were used as starter mixed culture was better than single culture in acid production and antibacterial activity. When starter was not inoculated in Dongchimi fermentation the numbers of Gram negatives and colifor-ms were remarkably increased in early phase and antibacterial activity could scarcely be detected. But when starter was inoculated the numbers of Gram negatives and coliforms were sharply decreased from early phase and antibacterial ctivity was high. When Dongchimi was made with heat sterilized mat-erials and starter there were no Gram negatives and coliforms and antibacterial activity was high. The antibacterial activity of starter inoculated Dongchimi was maximum in 2 days of fermentation at 2$0^{\circ}C$ and was scarcely detected in six days. In consideration of coliform counts antibacterial activity and the flavor of Dongchimi the preparation method in which all materials were heat treated at 8$0^{\circ}C$ for 15 min-utes and inoculated with mixed starter of the two strains and fermented for 2 days at 2$0^{\circ}C$ was thoug-ht to be good.

• Fisheries and Aquatic Sciences
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• 제19권10호
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• pp.42.1-42.10
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• 2016

The objectives of this study were to identify the histamine-forming bacteria and bacteriocin- producing lactic acid bacteria (LAB) isolated from Myeolchi-jeot according to sequence analysis of the 16S rRNA gene, to evaluate the inhibitory effects of the bacteriocin on the growth and histamine accumulation of histamine-forming bacteria, and to assess the physico-chemical properties of the bacteriocin. Based on 16S rRNA gene sequences, histamine-forming bacteria were identified as Bacillus licheniformis MCH01, Serratia marcescens MCH02, Staphylococcus xylosus MCH03, Aeromonas hydrophila MCH04, and Morganella morganii MCH05. The five LAB strains identified as Pediococcus acidilactici MCL11, Leuconostoc mesenteroides MCL12, Enterococcus faecium MCL13, Lactobacillus sakei MCL14, and Lactobacillus acidophilus MCL15 were found to produce an antibacterial compound with inhibitory activity against the tested histamine-producing bacteria. The inhibitory activity of these bacteriocins obtained from the five LAB remained stable after incubation at pH 4.0-8.0 and heating for 10 min at $80^{\circ}C$; however, the bacteriocin activity was destroyed after treatment with papain, pepsin, proteinase K, ${\alpha}$-chymotrypsin, or trypsin. Meanwhile, these bacteriocins produced by the tested LAB strains also exhibited histamine-degradation ability. Therefore, these antimicrobial substances may play a role in inhibiting histamine formation in the fermented fish products and preventing seafood-related food-borne disease caused by bacterially generated histamine.

• Food Science and Biotechnology
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• 제15권6호
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• pp.948-953
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• 2006

The D-form of lactic acid is frequently detected in fermented foods, and an excessive dietary intake of D-lactic acid may induce metabolic stress in both infants and patients. This work was carried out to determine the prevailing microorganisms relevant to the accumulation of D-lactic acid in kimchi. Leuconostoc (Leuc.) mesenteroides and Leuc. citreum primarily synthesized D-lactate with a small quantity of L-form. Leuc. gelidum and Leuc. inhae evidenced patterns similar to this. Lactobacillus (Lb.) plantarum and Lb. brevis were shown to convert glucose into a balanced mixture of D-/L-lactic acid, whereas Lb. casei principally synthesized L-lactic acid and a very small quantity of D-lactic acid. When kimchi was incubated at 8 or $22^{\circ}C$, D-lactic acid was over-produced than L-form. Leuconostoc was determined as the primary producer between the initial to mid-phase of fermentation and Lb. plantarum or Lb. brevis seemed to boost D-lactic acid content during later stage of acid accumulation.

• 한방비만학회지
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• 제16권1호
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• pp.11-18
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• 2016

Objectives: To confirm microbiological change and cytoprotective effect of Samjung-hwan (SJH) which fermented by Lactic acid bacteria from natural fermented SJH. Methods: SJH was fermented by Lactobacillus brevis and Lactococcus lactis subsp. lactis from natural fermented SJH. After 1 week of fermentation, we analysed pH and microbial profiling. We also performed measuring total polyphenol total flavonoid contents and 1,1-Diphenyl-2-picryhydrazyl (DPPH) free radical scavenging activity to investigate antioxidant ability. Cell viability was performed by using HepG2 cell. Results: pH of lactic acid bacteria inoculated group and non-inoculated group was decreased and total counts of lactic acid bateria for both group was increased after fermentation of SJH. Total polyphenol and flavonoid contents and DPPH free radical scavenging activity was increased in both group. Total polyphenol contents of lactic acid bacteria Inoculated group is more increased than non-inoculated group. HepG2 cell viability was increased in both group. Conclusions: SJH fermentd by Lactobacillus brevis and Lactococcus lactis subsp. lactis shows change in microbiological character and has cytoprotective effect. Further studies are required for investigating function of lactic acid bacteria during fermentation of SJH.

• 한국식품과학회지
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• 제16권3호
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• pp.285-290
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• 1984

유청(乳淸)과 두유(豆乳)의 공동침전(共同沈澱)에 의해 치즈를 제조하기 위한 기초실험으로서 유청-두유 혼합액에서 6종의 유산균들의 생육특성을 조사하였다. S. cremoris와 L. acidophilus가 두유와 유청-두유 혼합액에서 다 같이 많은 산을 생성하였다. 그러나 모든 유산균들이 두유에서 보다는 유청-두유 혼합액에서 더 많은 산을 생성하였고 이것은 특히 S. lactis와 S. cremoris에서 현저하였다. S. lactis와 S. cremoris 혼합균주의 생균수는 두유에서보다 유청-두유혼합액에서 약10배정도 많았다. 유청-두유 혼합액에서 산생성이 증가되는 것은 유청중에 존재하는 유당의 효과에 주로 기인한 것으로 나타났다. 두유에서의 산생성을 촉진키 위해 첨가하는 유당의 적정량은 두유 100ml당 0.8g으로 밝혀졌다.

• 방사선산업학회지
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• 제5권2호
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• pp.175-178
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• 2011

This study was conducted with effect of lactic acid bacteria by gamma irradiation. Lactic acid bacteria were exposed to irradiation with a single absorbed dose of 1, 2, 3, 4, 5, 6, 8, and 10 kGy. Possible lactic acid bacteria, including Lactobacillus paracasei KCTC 13169, Lactobacillus casei KCTC 3109, Lactobacillus acidophilus KCTC 3140, Lactobacillus plantarum subsp plantarum KCTC 3103, Lactobacillus debruekii subsp bulgaricus KCTC 3635, Streptococcus thermophilus KCTC 3658 were selected. The radiation sesitivities of lactic acid bacteria were expressed as $D_{10}$ values. The $D_{10}$ values of Lactobacillus paracasei, Lactobacillus casei, Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus debruekii were calculated as 0.42, 0.51, 0.47, 0.90, 0.44, and 0.61 kGy, respectively. Results suggest that L. acidiphilus has the highly resistant to gamma irradiation.

• Journal of Microbiology and Biotechnology
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• 제27권5호
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• pp.869-877
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• 2017

Lactic acid bacteria (LAB) are used as fermentation starters in vegetable and dairy products and influence the pH and flavors of foods. For many centuries, LAB have been used to manufacture fermented foods; therefore, they are generally regarded as safe. LAB produce various substances, such as lactic acid, ${\beta}$-glucosidase, and ${\beta}$-galactosidase, making them useful as fermentation starters. Existing functional substances have been assessed as fermentation substrates for better component bioavailability or other functions. Representative materials that were bioconverted using LAB have been reported and include minor ginsenosides, ${\gamma}$-aminobutyric acid, equol, aglycones, bioactive isoflavones, genistein, and daidzein, among others. Fermentation mainly involves polyphenol and polysaccharide substrates and is conducted using bacterial strains such as Streptococcus thermophilus, Lactobacillus plantarum, and Bifidobacterium sp. In this review, we summarize recent studies of bioconversion using LAB and discuss future directions for this field.

• Journal of Microbiology and Biotechnology
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• 제21권1호
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• pp.62-70
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• 2011

The antibacterial effects of nine lactic acid bacteria (LAB) against Campylobacter jejuni were investigated by using agar gel diffusion and co-culture assays. Some differences were recorded between the inhibition effects measured with these two methods. Only two LAB, Lb. pentosus CWBI B78 and E. faecium THT, exhibited a clear anti- Campylobacter activity in co-culture assay with dehydrated poultry excreta mixed with ground straw (DPE/GS) as the only growth substrate source. It was observed that the supplementation of such medium with a cellulase A complex (Beldem S.A.) enhanced the antimicrobial effect of both LAB strains. The co-culture medium acidification and the C. jejuni were positively correlated with the cellulase A concentration. The antibacterial effect was characterized by the lactic acid production from the homofermentative E. faecium THT and the lactic and acetic acids production from the heterofermentative Lb. pentosus CWBI B78. The antagonistic properties of LAB strains and enzyme combination could be used in strategies aiming at the reduction of Campylobacter prevalence in the poultry production chain and consequently the risk of human infection.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.285-285
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• 2017

This study is aimed to analyze the effect of lactic acid bacteria inoculants (LAB) on quality of rye silage fermentation, harvested at early heading stage. The nutritive values were similar between the control and LAB inoculated silages. The pH of rye silage in LAB inoculation significantly decreased as compared to control (p<0.05). In addition, the content of lactic acid in LAB inoculation significantly increased (p<0.05), but the content of acetic acid in LAB treatments decreased. In addition, lactic acid bacterial counts in LAB inoculation significantly increased as compared to control (p<0.05). Therefore, we suggest that rye silage could be improved by novel lactic acid inoculation.