• 한국식품영양학회지
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• 제25권4호
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• pp.951-956
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• 2012

This research was carried out in order to discover acid-forming bacteria during fermentation of Makgeolli, as Makgeolli loses its commercial value due to overproduced acidic materials. In Makgeolli kept at $25^{\circ}C$, a sudden increase of acidity as well as the disappearance of yeast cells occurred at day 6, whereas the total cell count and bacterial type remained unchanged; the result implies that a succession of bacterial types, including acid forming bacteria, occurred. Two acid-forming bacteria were isolated from acidified Makgeolli and were identified as Acetobacter pasteurianus and Lactobacillus casei. When fresh and heat-treated Makgeolli were inoculated with Acetobacter pasteurianus and/or Lactobacillus casei, the greatest amount of acid was formed in Makgeolli inoculated with Acetobacter pasteurianus and Lactobacillus casei and also in Makgeolli with Acetobacter pasteurianus alone. This result indicates that Acetobacter pasteurianus is the main acidifier; furthermore, it shows the synergy effect in acid formation with Lactobacillus casei.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• 제15권7호
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• pp.1031-1035
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• 2002

This study was carried out to obtain conjugated linoleic acid (CLA) producing lactic acid bacteria for further study on the enzymes related to the production of CLA which has gained considerable attention and on the development as a probiotic culture. Total 34 lactic acid bacteria were isolated from 19 feces samples of healthy babies. CLA forming ability was measured spectrophotometrically by the modification of linoleate 12-cis, 11-trans-isomerase activity measuring method, and CLA of the cultures were extracted, methylated, and examined by HPLC analysis. CLA methyl ester of only one culture showing the highest value of CLA forming ability could be detected by HPLC analysis. The culture was found to be Gram positive, rods and catalase negative. It grows at $45^{\circ}C$ but not at $15^{\circ}C$, and was identified to be Lactobacillus fermentum on the basis of the biochemical characteristics and the utilization of substrates. These results provide an efficient experimental method to screen CLA producing lactic acid bacteria.

• Journal of Dairy Science and Biotechnology
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• 제22권2호
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• pp.99-106
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• 2004

포자형성 유산균주에 대하여 종양세포에 대한 증식 억제 활성과 항산화 활성 및 세포내 glutathione 함유율을 측정하였다. 종양세포에 대한 억제활성은 균주에 따라 큰 차이를 나타내었고 Bacillus coagulans KTCC 3675는 높은 수준의 특이한 수준의 억제 활성을 나타내었고 human lymphoma cell NCLH-1299에 대한 억제 활성은 미약한 수준인 것으로 확인되었다. TBA 방법에 의한 linoleic acid에 대한 항산화 활성은 5~25% 정도의 항산화 활성을 보였고 특별히 높은 수준의 항산화 활성을 보인균주는 Bacillus coagulans KTCC 625, Bacillus coagulans KTCC 1015 및 Lactobacillus sporogens CU 815인 것으로 확인되었다. 포자형성 유산균체 추출액의 linoleic acid과산화 억제 활성과 세포내 glutathione함유율과의 상관계수는 0.78로서 고도의 유의성이 인정되는 상관계수를 나타내었다.

• Journal of Applied Biological Chemistry
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• 제63권4호
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• pp.375-385
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• 2020

본 연구의 목적은 발효 기간 동안 멸치 액젓과 새우젓으로 담근 배추 김치로부터 분리 동정된 바이오제닉 아민(biogenic amines, BA) 생성 유산균 단독 스타터 혹은 BA 분해 유산균과의 혼합 스타터로 제조한 김치의 품질 특성을 조사하고자 하였다. 발효가 진행될수록 새우젓 보다 멸치 액젓을 첨가하여 제조한 김치에서 유산균수, 산도 및 BA 함량이 높게 나타났다. 유산균이 생산하는 BA의 종류 및 생성량은 균종 보다는 균주에 의존적이었다. 분리 균주 중에서 가장 많은 양의 카다베린, 히스타민, 푸트레신 및 티라민은 각각 Leuconostoc mesenteroides MBK32, Lactobacillus brevis MBK34, Lactobacillus curvatus MBK31 및 Enterococcus faecalis SBK31로부터 생산되었다. BA 생성능과 분해능이 있는 스타터는 김치 내 유산균의 증식 속도와 산 생성능에 중요한 역할을 하였다. BA 생성균 단독 스타터에 의해 증가된 김치의 BA 함량은 BA 분해균과의 혼합 스타터에 의해 효과적으로 감소되었다.

• Journal of Microbiology and Biotechnology
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• 제30권9호
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• pp.1404-1411
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• 2020

Lactic acid bacteria (LAB) play an important role in dairy fermentations, notably as cheese starter cultures. During the cheese production and ripening period, various enzymes from milk, rennet, starter cultures, and non-starter LABs are involved in flavor formation pathways, including glycolysis, proteolysis, and lipolysis. Among these three pathways, starter LABs are particularly related to amino acid degradation, presumably as the origins of major flavor compounds. Therefore, we used several enzymes as major criteria for the selection of starter bacteria with flavor-forming ability. Lactococcus lactis subsp. lactis LDTM6802 and Lactococcus lactis subsp. cremoris LDTM6803, isolated from Korean raw milk and cucumber kimchi, were confirmed by using multiplex PCR and characterized as starter bacteria. The combinations of starter bacteria were validated in a miniature Gouda-type cheese model. The flavor compounds of the tested miniature cheeses were analyzed and profiled by using an electronic nose. Compared to commercial industrial cheese starters, selected starter bacteria showed lower pH, and more variety in their flavor profile. These results demonstrated that LDTM6802 and LDTM6803 as starter bacteria have potent starter properties with a characteristic flavor-forming ability in cheese.

• 한국물환경학회지
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• 제20권4호
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• pp.339-345
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• 2004

The characteristics of $H_2$ production from livestock wastewater were investigated through an anaerobic acid forming process using Clostridium beijerinckii and the photosynthetic process using Rhodobacter sphaeroides. The submerged separation membrane was installed in the acid forming reactor, The photosynthetic process is composed of two reactors(photosynthetic reactor 1 and photosynthetic reactor 2) which is connected continually. The removal rate of COD and the production of volatile fatty acid(VFA) in the acid forming process were approximately 50% and 1000mg/L, respectively. The 70% of COD in the effluent of acid forming process was removed through the photosynthetic process. The production of $H_2$ in the photosynthetic reactor 1 and 2 was 50 and $25mLH_2/gVFA_{COD}$, respectively. The values of Y in acid forming reactor, photosynthetic reactor 1 and 2 was 0.2263, 0.0601 and 0.0393, respectively. The acetic acid and butyric acid produced in acid forming process were converted to $H_2$ by photosynthetic bacteria.

• 농업과학연구
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• 제37권3호
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• pp.451-455
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• 2010

Cabbage, the main material of coleslaw was not safely washed because it is uneven and tightly layered. In this study, vinegar was used to control the number of E. coli in cabbage for coleslaw production. When cabbage was soaked in 10% acetic acid, The number of bacteria was reduced by $10^{-3}$ was survived after 5min and $10^{-6}$ after 30min. After soaking, 15-20% (w/w of cabbage) of 10% acetic acid was remained in chopped cabbage. Spraying 10% acetic acid up to 3% of cabbage weight decreased the number of bacteria by 1/1000 after 60min. Spraying 3% (v/w of cabbage) of vinegar containing 10% acidity decreased the bacteria by 2/3 after 20min but no further decrease was observed. This result indicated that vinegar can be used only in the case that contamination is low.

• 한국식품저장유통학회지
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• 제20권5호
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• pp.705-711
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• 2013

비단백질 구성 아미노산인 gamma amino butyric acid(GABA)는 뇌에서 억제성 신경전달물질로 작용하며 혈압 저하, 신경 안정, 이뇨 작용 등에 효과가 있는 것으로 알려져 있다. 김치로부터 두유에서 커드를 형성하는 40개 균주를 분리하였다. GABA 생산력이 높은 균주를 선별하기 위하여 분리된 균주들을 두유에 접종하여 $37^{\circ}C$에서 48시간동안 발효하였다. 분리된 균주들 가운데 발효두부에서 가장 높은 GABA 를 생산하는 383 균주는 API 분석과 16S rDNA sequence를 통하여L. sakei로 동정되었으며 L. sakei 383으로 명명하였다. L. sakei 383은 MRS 배지에서 $35^{\circ}C$, 24시간 배양할 때 가장 높은 생육을 나타내었으며 두유에 균을 접종하여 $35^{\circ}C$에서 18시간 발효 했을 때를 GABA 생산을 위한 최적 배양 조건으로 정하였으며 최대 GABA 함량은 8.65 mg/100 g이었다.

• 한국식품영양과학회지
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• 제28권5호
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• pp.1069-1075
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• 1999

The sterilization was attempted to improve the quality deterioration of soybean paste during its storage. For this experiment, soybean paste was sterilized at 80oC for 30 minutes and stored during 6 months at 15oC and 30oC, respectively. The total approximate composition contents were moisture 52.5%, crude protein 11.94%, crude fat 2.0%, amino nitrogen 413.3mg%, sodium chloride 11.61% and ash 15.5%. According to the increase of storage period, pH was decreased gradually because of the increase of organic acids by the metabolism of microorganisms and the acid accumulation by acid forming bacteria, but titratable acidity was increased during storage. Amino nitrogen was rapidly increased for the first one or two month storage period and maintained as the same level for the rest of them. Each amino acid contents of soybean paste, which were glutamic acid, tryptophan, proline, arginine, and aspartic acid, had much higher level than others. In color changes sterilized soybean paste(SSP) was much lower than that of raw ones(RSP). Hunter L and b values on the surface of soybean paste were decreased during storage, and the decreasing levels were higher at 30oC than at 15oC. Hunter a value, however, was increased a little in the initial storage, and thereafter it was decreased. Lactic acid bacteria, yeasts, and molds were disappeared completely by the sterilization. However, the bacteria of aerobes and anaerobes were not disappeared by this processing.