• 한국축산식품학회지
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• 제41권1호
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• pp.145-152
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• 2021

Microbial bioconversion using lactic acid bacteria (LAB) provides several human health benefits. Although whey and whey-derived bioactive compounds can contribute to an improvement in human health, the potential anti-obesity effect of whey bioconversion by LAB has not been well studied. This study aimed to investigate whether bioconversion of whey by Pediococcus pentosaceus KI31 and Lactobacillus sakei KI36 (KI31-W and KI36-W, respectively) inhibits 3T3-L1 preadipocyte differentiation. Both KI31-W and KI36-W reduced intracellular lipid accumulation significantly, without decreasing 3T3-L1 preadipocyte proliferation. In addition, obesity-related transcription factor (peroxisome proliferator-activated receptor γ) and genes (adipocyte fatty acid-binding protein and lipoprotein lipase) were down-regulated significantly in 3T3-L1 cells in the presence of KI31-W and KI36-W. Collectively, these results suggest that bioconversion of whey by LAB exhibits anti-adipogenic activity and may be applied as a therapeutic agent for obesity.

• 한국초지조사료학회지
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• 제41권3호
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• pp.176-182
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• 2021

Ensiling is the most preferred technology to preserve the silage quality with high nutrients by the presence of lactic acid bacteria. In this study, lactic acid bacteria RJ1 and S22 were used to make the silages from different leguminous plants such as alfalfa, hairy vetch and red clover. Experimental groups were divided into control and LAB inoculated groups. LAB inoculated group; all legumes treated with a mixture of RJ1 and S22 and made an anaerobic condition for 45d. Without the addition of LAB considered the control group. The results showed that the lactic acid content was higher in all silages in response to LAB treatment and acetic acid content was slightly increased except red clover by LAB compared to control silages. A poor silage quality marker butyric acid was reduced all legume silages in response to LAB inoculation than control silages. The organic acid is closely associated with microbial population experimental silages. We noted that higher LAB and lower yeast were found in the silage in response to LAB treatment. The contents of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and total digestible nutrient (TDN) were not altered significantly between control and LAB treated silages. Overall data suggested that the inclusion of additional LAB potentially enhance the silage quality and preserved the nutrients for long period.

• 한국초지조사료학회지
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• 제37권3호
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• pp.189-194
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• 2017

The present study analyzes the role of Lactic Acid Bacteria Mixture (LBM) on improving rye silage quality. Rye of four different stages (Booting, Heading, Flowering, and Late flowering) was collected and silage was prepared. The nutrient profile analysis of experimental silage groups showed no significant changes between control and LBM inoculation. Interestingly, the pH of rye silage in LBM treatments showed significant reduction than control (p<0.05) in all stages of rye silage. However, lowest pH (3.69) resulted on booting stage among other stages of rye. Subsequently significant lactic acid production was noted in all stages of LBM inoculation than control. Conversely maximum lactic acid production of (5.33%DM) was noted at booting stage followed by (4.86%DM) in heading stage. Further the lactic acid bacterial (LAB) count in LBM inoculated group showed significant increase than control. Similarly, the silage of booting stage group registered maximum LAB population ($63.7{\times}10^6CFU/g$) after that heading stage ($32.3{\times}10^6CFU/g$). Further significant reduction in yeast growth and no fungal growth was noted in all LPM treatment groups. Hence, LBM inoculants could be a better additive for improving rye silage quality.

• Journal of Microbiology and Biotechnology
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• 제27권11호
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• pp.2019-2027
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• 2017

Recently, cabbage kimchi has occasionally been associated with the foodborne diseases of enteric viruses such as human norovirus (HuNoV). This study aimed to evaluate the correlation between microbial/physicochemical properties and persistence of HuNoV in experimentally contaminated cabbage kimchi fermented and stored at $4^{\circ}C$ or $10^{\circ}C$ for 28 days. Changes in organic acid content, lactic acid bacteria (LAB), acidity, pH, and salinity were analyzed. The recovery of structurally intact HuNoV was examined for up to 28 days post-inoculation, using a NoV GII.4 monoclonal antibody-conjugated immuno-magnetic separation method combined with quantitative real-time reverse transcription polymerase chain reaction. On day 0, LAB loads were $4.70log_{10}$ colony forming units/g and HuNoV GII.4 titers were $2.57log_{10}\;genomic\;copies/{\mu}l$, at both temperatures. After 28 days, intact HuNoV titers decreased to 1.58 ($4^{\circ}C$) and $1.04(10^{\circ}C)log_{10}\;genomic\;copies/{\mu}l$, whereas the LAB density increased. This correlated with a gradual increase in lactic acid and acetic acid at both temperatures. Our findings support a statistical correlation between changes in physicochemical properties and the recovery of structurally intact HuNoV GII.4. Moreover, we determined that the production of organic acid and low pH could affect HuNoV GII.4 titers in cabbage kimchi during fermentation. However, HuNoV GII.4 was not completely eliminated by microbial/physicochemical factors during fermentation, although HuNoV GII.4 was reduced. Based on this, we speculate that the persistence of HuNoV GII.4 may be affected by the continually changing conditions during kimchi fermentation.

• Asian-Australasian Journal of Animal Sciences
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• 제33권1호
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• pp.100-110
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• 2020

Objective: The objective of this study was to isolate proteolytic microorganisms and evaluate their effects on proteolysis in total mixed ration (TMR) silages of soybean curd residue. Methods: TMRs were formulated with soybean curd residue, alfalfa or Leymus chinensis hay, corn meal, soybean meal, a vitamin-mineral supplement, and salt in a ratio of 25.0: 40.0:30.0:4.0:0.5:0.5, respectively, on a basis of dry matter. The microbial proteinases during ensiling were characterized, the dominate strains associated with proteolysis were identified, and their enzymatic characterization were evaluated in alfalfa (A-TMR) and Leymus chinensis (L-TMR) TMR silages containing soybean curd residue. Results: Both A-TMR and L-TMR silages were well preserved, with low pH and high lactic acid concentrations. The aerobic bacteria and yeast counts in both TMR silages decreased to about 10⁵ cfu/g fresh matter (FM) and below the detection limit, respectively. The lactic acid bacteria count increased to 10⁹ cfu/g FM. The total microbial proteinases activities reached their maximums during the early ensiling stage and then reduced in both TMR silages with fermentation prolonged. Metalloproteinase was the main proteinase when the total proteinases activities reached their maximums, and when ensiling terminated, metallo and serine proteinases played equally important parts in proteolysis in both TMR silages. Strains in the genera Curtobacterium and Paenibacillus were identified as the most dominant proteolytic bacteria in A-TMR and L-TMR, respectively, and both their proteinases were mainly with metalloproteinase characteristics. In the latter ensiling phase, Enterococcus faecium strains became the major sources of proteolytic enzymes in both TMR silages. Their proteinases were mainly of metallo and serine proteinases classes in this experiment. Conclusion: Proteolytic aerobic bacteria were substituted by proteolytic lactic acid bacteria during ensiling, and the microbial serine and metallo proteinases in these strains played leading roles in proteolysis in TMR silages.

• 한국식품과학회지
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• 제29권3호
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• pp.476-481
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• 1997

두부의 저장성에 미치는 수용성 키토산 분해물질의 영향을 알아 보기 위해 두부침지액으로 일반 시중 두부공장에서 사용하는 수돗물, 멸균증류수, 0.5% 키토산 분해물질, 0.5% fumaric acid, 0.5% lactic acid를 사용하여 $4^{\circ}C$에서 냉장저장하면서 pH와 탁도, 그리고 미생물상의 변화를 관찰하였다. 수용성 키토산 분해물질을 첨가한 침지액의 경우 총균수가 21일 저장시 $10^{7}\;CFU/mL$에 달해 다른 침지액에 비해 7일에서 14일의 저장기간 연장을 관찰할 수 있었다. 특히 초기 오염 미생물의 lag phase가 다른 군에 비해 상당히 길어진 것을 관찰할 수 있었다. Yeast와 mold, 그리고 E. coli의 경우도 시간이 경과됨에 따라 증가하였으며, 0.5% 키토산 분해물질 첨가 침지액의 경우가 다른 침지액의 경우보다 증가율이 적음을 알 수 있었다. 이는 수용성 키토산 분해물질의 항균효과를 잘 보여주고 있다. 초기 pH는 0.5% fumaric acid와 lactic acid의 경우 pH 4.68과 pH 5.12로 상당히 낮았으며, 수돗물과 멸균증류수, 0.5% 키토산 분해물질 첨가 침지액에서는 pH 7.2로 비슷하였고, 저장 초기에 약간 감소하다가 서서히 증가하는 경향을 보였다. 탁도의 변화는 미생물상의 변화와 연관시켜 두부가 부패된 것으로 간주되는 총균수 $10^{7}\;CFU/mL$이상에서 0.2를 초과해 탁도가 두부부패정도를 파악하는 한 척도가 될 수 있다고 판단된다. 상기 결과로부터 항균성을 가지는 수용성 키토산 분해물질을 첨가한 두부 침지액의 개발은 두부의 저장성 향상에 크게 기여할 것으로 사료된다.

• 생명과학회지
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• 제28권1호
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• pp.68-77
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• 2018

바이오제닉 아민 비생성 유산균의 선별을 위해 순창군에서 재배된 베리류 및 엑기스, 식초 등으로부터 42종의 유산균을 분리하였다. 분리주를 대상으로 세포외 효소 활성, 항균 활성, 항산화 활성과 같은 다양한 생리활성 분석을 실시하여 5종의 분리주를 1차 선별하였다. 분리주를 대상으로 바이오제닉 아민 생성 여부를 분석하여 최종적으로 SBB07을 선별하였고, 16S rRNA 염기서열 분석을 통해 Lactobacillus brevis SBB07로 명명하였다. SBB07의 프로바이오틱스 활용 가능성을 확인하기 위해 효소 생산 여부, 내산성, 내담즙성, 내열성, 항생제 내성을 조사하였고, pH 2.0에서의 내산성 및 0.5% oxgall을 함유한 내담즙성에서 각각 86% 이상과 54% 이상의 높은 생존율을 나타내었다. 또한 $60^{\circ}C$에서도 113% 이상의 생존율을 나타내어 내열성도 우수하며 다양한 항생제 내성을 갖는 것을 확인하였다. 프리바이오틱스 이용가능성을 확인한 결과에서는 GOS의 이용 능력이 가장 우수하였으며, FOS와 inulin의 이용 능력도 높게 나타났다. 따라서 SBB07은 세포외 효소 및 항균 활성이 우수하고, 내담즙, 내산성, 내열성 및 항생제 내성을 지니며 프리바이오틱스 기질 이용 능력도 우수한 프로바이오틱스 소재로 활용가능성이 높은 유산균으로 기대된다.

• Asian-Australasian Journal of Animal Sciences
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• 제31권4호
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• pp.585-594
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• 2018

Objective: This study was to determine the bacterial diversity and monitor the community dynamic changes during storage of vacuum-packaged sliced raw beef as affected by Lactobacillus sakei and Lactobacillus curvatus. Methods: L. sakei and L. curvatus were separately incubated in vacuumed-packaged raw beef as bio-protective cultures to inhibit the naturally contaminating microbial load. Dynamic changes of the microbial diversity of inoculated or non-inoculated (control) samples were monitored at $4^{\circ}C$ for 0 to 38 days, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Results: The DGGE profiles of DNA directly extracted from non-inoculated control samples highlighted the order of appearance of spoilage bacteria during storage, showing that Enterbacteriaceae and Pseudomonas fragi emerged early, then Brochothrix thermosphacta shared the dominant position, and finally, Pseudomonas putida showed up became predominant. Compared with control, the inoculation of either L. sakei or L. curvatus significantly lowered the complexity of microbial diversity and inhibited the growth of spoilage bacteria (p<0.05). Interestingly, we also found that the dominant position of L. curvatus was replaced by indigenous L. sakei after 13 d for L. curvatus-inoculated samples. Plate counts on selective agars further showed that inoculation with L. sakei or L. curvatus obviously reduced the viable counts of Enterbacteraceae, Pseudomonas spp. and B. thermosphacta during later storage (p<0.05), with L. sakei exerting greater inhibitory effect. Inoculation with both bio-protective cultures also significantly decreased the total volatile basic nitrogen values of stored samples (p<0.05). Conclusion: Taken together, the results proved the benefits of inoculation with lactic acid bacteria especially L. sakei as a potential way to inhibit growth of spoilage-related bacteria and improve the shelf life of vacuum-packaged raw beef.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.460-460
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• 2003

• 한국식품과학회지
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• 제34권2호
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• pp.296-302
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• 2002

통밀과 파쇄밀로 만든 누룩을 대조구로 하고, 밀가루를 이용하여 만든 재래식의 밀가루 누룩, 밀가루와 쌀의 혼용 누룩 및 Aspergillus oryzae의 누룩으로 각각 탁주를 담금하여 발효 과정 중의 품질을 검토한 결과는 다음과 같다. 에탄올 함량은 발효 14일에 $10.6{\sim}17.4%$로 최대치를 보였으며 대조구, 밀가루 누룩구, Aspergillus oryzae 누룩구, 쌀 혼용구의 순으로 높았다. pH는 시험구간에 차이가 없었으나, 총산은 재래식 밀가루 누룩구에서 높았다. 총당은 담금일에 $16.22{\sim}17.74%$로 가장 높았으나 14일에 $4.28{\sim}6.10%$로 현저히 감소되었다. 발효초기에 Aspergillus oryzae구에서 높았으나 이후는 총당의 차이가 없는 편이었다. 유리당중 glucose는 담금일에 $2,735{\sim}7,842\;mg%$로 월등히 높았으나 이후 현저히 감소하였다. 유리당 총량은 대조구와 재래식 밀가루 누룩구에서 높았다. 유리당 총량은 대조구에서 $690{\sim}2,241\;mg%$로, lactic acid+succinic acid는 쌀 혼용구에서 $183{\sim}1,293\;mg%$로 각각 높았고, 확인된 6종의 유기산중 lactic acid+succinic acid가 탁주에서 가장 함량이 많았다.