• Journal of Dairy Science and Biotechnology
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• 제39권3호
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• pp.121-127
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• 2021

Yogurt is produced by bacterial fermentation of milk and contains lactic acid bacteria (LAB), which produce various metabolites such as organic acid, hydrogen peroxide, and bacteriocin. This study aimed to investigate cell-free supernatants (CFS) of LAB isolated from Tibetan yogurt. CFS (TY1, TY2, TY3, TY4, TY5, TY6, and TY7) from selected strains of LAB were co-incubated with four different foodborne pathogenic bacteria, namely E. coli O157:H7, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. Inhibition of foodborne pathogenic bacterial growth was not affected in the presence of CFS (pH 6.5). In contrast, CFS without neutralization completely inhibited the growth of the bacteria. Furthermore, when the concentration of CFS (without neutralization) was changed to 1:4 and 1:8, a difference in inhibition was observed between Gram-positive and Gram-negative bacteria. CFS more effectively inhibited the growth of Gram-negative E. coli O157:H7 and S. Typhimurium than Gram-positive L. monocytogenes and S. aureus. These results suggest that organic acids in LAB may inhibit the growth of foodborne pathogenic bacteria, particularly Gram-negative bacteria.

• 한국미생물·생명공학회지
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• 제25권2호
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• pp.224-228
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• 1997

This studies were carried out to investgate the effects of omija (Schizandra chinensis) extracts(OE) on the growth of lactic acid bacteria (LAB, HYO-1 and HYO-2) isolated from home-made kimchi. The growth of isolated LAB was inhibited apparently in modified MRS broth containing 1% or 2% of OE. The growth of isolated LAB was inhibited by pH control with HCI to 4.3 or 3.7, the same pH of modified MRS broth containing 1% or 2% of OE. The strong growth inhibitory properties against isolated LAB were shown by fumaric and itaconic acid among various organic acids of Schizandra chinensis, such as citric acid, malic acid, lactic acid, fumaric acid, itaconic acid and acetic acid. The isolated LAB were indentified as Lactobacillus plantarum.

• Asian-Australasian Journal of Animal Sciences
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• 제28권8호
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• pp.1123-1132
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• 2015

Winter wheat is a suitable crop to be ensiled for animal feed and China has the largest planting area of this crop in the world. During the ensiling process, lactic acid bacteria (LAB) play the most important role in the fermentation. We investigated the natural population of LAB in whole-crop wheat (WCW) and examined the quality of whole-crop wheat silage (WCWS) with and without LAB inoculants. Two Lactobacillus plantarum subsp. plantarum strains, Zhengzhou University 1 (ZZU 1) selected from corn and forage and grass 1 (FG 1) from a commercial inoculant, were used as additives. The silages inoculated with LAB strains (ZZU 1 and FG 1) were better preserved than the control, with lower pH values (3.5 and 3.6, respectively) (p<0.05) and higher contents of lactic acid (37.5 and 34.0 g/kg of fresh matter (FM), respectively) (p<0.05) than the control. Sixty LAB strains were isolated from fresh material and WCWS without any LAB inoculation. These LAB strains were divided into the following four genera and six species based on their phenotypic, biochemical and phylogenetic characteristics: Leuconostoc pseudomesenteroides, Leuconostoc citreum, Weissella cibaria, Lactococcus lactis subsp. lactis, Lactobacillus buchneri, and Lactobacillus plantarum subsp. plantarum. However, the prevalent LAB, which was predominantly heterofermentative (66.7%), consisted of Leuconostoc pseudomesenteroides, Leuconostoc citreum, Weissella cibaria, and Lactobacillus buchneri. This study revealed that most of isolated LAB strains from control WCWS were heterofermentative and could not grow well at low pH condition; the selective inoculants of Lactobacillus strains, especially ZZU 1, could improve WCWS quality significantly.

• 한국식품영양학회지
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• 제31권6호
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• pp.940-948
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• 2018

The aim of this study was to investigate the immune activity of Ailantias altissima as an active ingredient on the immune enhancement by mixing ethanol extract with lactic acid bacteria (LAB). The activity of $NF-{\kappa}B/AP1$ transcription factor increased by $NF-{\kappa}B$ activity when mixed with LAB samples rather than with the extract alone. Nitric oxide (NO) production was similar in ethanol extract alone group and LPS treatment group. Mixing Ailantias altissima extract and lactic acid bacteria led to low NO production. The cytokine productivity of $TNF-{\alpha}$ significantly increased in Ailantias altissima extract when treated with LPS, and increased even more when mixed with lactic acid bacteria. The $IL-1{\beta}$ cytokine production was high when the Ailantias altissima extract were treated alone, but no $IL-1{\beta}$ cytokine was produced in the mixtures with isolates. The combination of the ethanol extract of the Ailantias altissima and the lactic acid bacteria was found to be effective in the immune function. Consequently, the ingredient to combine Ailantias altissima extract and lactic acid bacteria can be effectively used for development of the health functional food on the prevention and treatment of hypoimmunities.

• 한국초지조사료학회지
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• 제35권2호
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• pp.159-165
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• 2015

본 연구는 충남 천안 국립축산과학원 식용벼 재배지에서 2012년부터 2013년까지 정상적으로 벼 재배가 이루어지고 수확이 완료된 볏짚을 이용하여 수행하였다. 젖산균 접종 유무에 따라 볏짚사일리지의 사료가치 변화는 나타나지 않았으나 클로렐라 처리구는 대조구에 비해 현저하게 조단백질 함량이 증가하였다(p<0.05). 그리고 클로렐라 농도의 증가에 따라 조단백질 함량이 증가하는 경향을 보였다 (p<0.05). 모든 처리구에서 섬유소와 TDN 함량 및 in vitro 소화율은 차이를 나타내지 않았다. 그리고 젖산균 접종 유무에 따라 볏짚사일리지의 pH 및 유기산 함량 변화는 나타나지 않았으며 클로렐라 처리구도 무처리구에 비해 pH 변화는 나타나지 않았다. 그러나 클로렐라 처리구에서 젖산함량은 무처리구에 비해 유의적으로 증가하였으며 클로렐라 농도의 증가에 따라 젖산함량이 증가하는 경향을 보였다(p<0.05). 젖산균 단독접종구의 젖산균 수는 무처리구에 비해 현저하게 증가하였으며(p<0.05), 클로렐라 농도의 증가에 따라 증가하는 경향을 보였다(p<0.05). 그러나 효모와 곰팡이 수는 비슷한 수준을 나타냈다. 그러므로 볏짚사일리지의 사료가치와 품질은 클로렐라 첨가에 의해서 향상될 수 있다.

• 미생물학회지
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• 제54권2호
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• pp.113-125
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• 2018

본 연구에서는 히스타민을 생성하는 유산균과 이에 항균 활성을 나타내는 프로바이오틱 유산균을 혼합 접종하여 제조한 렌넷 커드 내 항균물질과 히스타민 생산에 영향을 미치는 인자를 조사하였다. 프로바이오틱 유산균인 Lactobacillus plantarum FIL20과 Lactobacillus sakei PIL52는 히스타민 생성균인 Lactobacillus brevis LAS129, Enterococcus faecium SBP12 및 Enterococcus faecalis SBP58에 대해 강력한 항균 물질을 생산하였고, 프로바이오틱균이 생산한 유산과 박테리오신의 항균 활성은 농도의존적이었다. 렌넷 커드 제조를 위해 접종한 프로바이오틱 유산균의 균수가 많을수록 항균 물질 생성량이 증가되어 히스타민 생성균에 대한 항균 활성도 높아졌다. 프로바이오틱 유산균과 히스타민 생성균은 NaCl 10% 첨가에 의해 증식이 억제됨으로써 렌넷 커드 내에 항균 물질과 히스타민의 함량은 대조구보다 유의하게 낮았다(P < 0.05). 한편, 프로바이오틱 유산균과 히스타민 생성균을 혼합하여 제조한 렌넷 커드를 $25^{\circ}C$에서 5일간 저장 했을 때 히스타민의 함량은 유의하게 증가되지 않았으나, $20^{\circ}C$에서 20일간 저장한 경우에는 프로바이오틱 유산균이 생산한 항균 물질의 활성이 감소됨에 따라 렌넷 커드 내에 히스타민의 함량이 유의하게 증가되었다(P < 0.05).

• Food Science and Biotechnology
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• 제15권5호
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• pp.664-671
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• 2006

Modeling the growth kinetics of lactic acid bacteria (LAB), one of the most valuable microbial groups in the food industry, has been actively pursued in order to understand, control, and optimize the relevant fermentation processes. Most modeling approaches have focused on the development of single population models. Primary single population models provide fundamental kinetic information on the proliferation of a primary LAB species, the effects of biological factors on cell inhibition, and the metabolic reactions associated with cell growth. Secondary single population models can evaluate the dependence of primary model parameters, such as the maximum specific growth rate of LAB, on the initial external environmental conditions. This review elucidates some of the most important single population models that are conveniently applicable to the LAB fermentation analyses. Also, a well-defined mixed population model is presented as a valuable tool for assessing potential microbial interactions during fermentation with multiple LAB species.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.490-495
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• 2007

Lactic acid bacteria (LAB) are beneficial for the gastrointestinal tract and reinforce immunity in human health. Recently, many functional products using the lactic acid bacteria have been developed. Among these LAB, Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium longum, and Bifidobacterium bifidum are frequently used for probiotic products. In order to monitor these LAB in commercial probiotic products, a multiplex PCR method was developed. We designed four species-specific primer pairs for multiplex PCR from the 16S rRNA, 16S-23S rRNA intergenic spacer region, and 23S rRNA genes in Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium longum, and Bifidobacterium bifidum. Using these primer pairs, 4 different LAB were detected with high specificity in functional foods. We suggest that the multiplex PCR method developed in this study would be an efficient tool for simple, rapid, and reliable identification of LAB used as probiotic strains.

• KSBB Journal
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• 제32권3호
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• pp.199-205
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• 2017

The aim of this study was to investigate probiotic characteristics and fermentation profile of selected lactic acid bacteria (LAB) isolated from traditional fermented foods. Antibacterial activity against various pathogens, acid and bile salt tolerance, cell hydrophobicity, and antibiotic resistance were examined. 16S rRNA sequencing was carried out to identify eight presumptive LAB isolates. In general, all identified LAB (Enterococcus faecium MG89-2, Lactobacillus plantarum MG207, L. paracasei MG310, L. casei MG311, Streptococcus thermophilus MG510, L. bulgaricus MG515, L. helveticus MG585, and L. fermentum MG590) showed strong antimicrobial activity. Also, the selected strains were resistant to bile acid up to 3% and their autoaggregation rates were as high as 60%. All selected strains tested were sensitive to chloramphenicol, tetracycline, and ampicillin, whereas resistant to nalidixic acid and kanamycin.

• Journal of Dairy Science and Biotechnology
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• 제41권1호
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• pp.34-43
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• 2023

Hydrolysis of whey-derived proteins using lactic acid bacteria (LAB) utilizes the mass culture method and fermentation of LAB to produce effective bioactive peptides. Whey protein has the biological potential of its precursors, but the active fragments may not be released depending on the hydrolysis method. As an alternative to these problems, the nutritional and bioactive functionality of the hydrolysis method have been reported to be improved using LAB for whey protein. Peptide fractions were obtained using a sample fast protein liquid chromatography device. Antioxidant activity was verified for each of the five fractions obtained. In vitro cell experiments showed no cytotoxicity and inhibited nitric oxide production. Cytokine (IL [interleukin]-1α, IL-6, tumor necrosis factor-α) production was significantly lower than that of lipopolysaccharides (+). As a result of checking the amino acid content ratio of the fractions selected through the AccQ-Tag system, 17 types of amino acids were identified, and the content of isoleucine, an essential amino acid, was the highest. These properties show their applicability for the production of functional products utilizing dietary supplements and milk. It can be presented as an efficient method in terms of product functionality in the production of uniform-quality whey-derived peptides.