• 한국수소및신에너지학회논문집
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• 제13권4호
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• pp.321-329
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• 2002

Clostridium butyricum, Lactobacillus amylophillus, Lactobacillus amylovorus, Lactobacillus acidophillus, AI-9 produced hydrogen and /or organic acids using glucose, lactose and starch at the anaerobic culture conditions. Cl. butyricum NCIB 9576 evolved 1,700 ml H2/L-culture broth and accumulated butyric acid, acetic acid, propionic acid and ethanol in its culture broth when lactose was used as a carbon source during 24 hrs of fermentation. L. amylovorus ATCC 33620 accumulated lactic and acetic acids and some reducing sugars when starch was used as a carbon source without hydrogen production. Instead of starch as a carbon source, L. amylovorus ATCC 33620 produced lactic acid from algal biomass during fermentation and the acid-heat or freeze-thaw pretreatment of algal biomass accelerate the lactic acid fermentation.

• KSBB Journal
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• 제32권2호
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• pp.153-159
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• 2017

The purpose of this study was to investigate the probiotic properties of lactic acid bacterial strains isolated from human feces. The properties were tested on the basis of guideline for probiotic selection protocol such as tolerance for acid or bile salt, autoaggregation, antibiotic resistance, and antimicrobial activity. Total 25 lactic acid bacteria were isolated from human feces, and their antibacterial activity was tested against Staphylococcus aureus, Escherichia coli, E. coli O157:H7, Vibrio parahaemolyticus, V. alginolyticus using an agar diffusion assay. Among them, 4 selected strains were identified by analysis of their 16S rRNA, as Lactobacillus rhamnosus MG316, L. acidophilus MG501, L. reuteri MG505, and L. gasseri MG570. Results show that resistance to low pH and bile salts. Also, the selected strains were resistant to bile acid up to 3% and their autoaggregation rates were as high as 60%. All strains tested were resistance to nalidixic acid and kanamycin.

• Macromolecular Research
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• 제9권5호
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• pp.259-266
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• 2001

Multiblock copolymer was synthesized by the copolycondensation of oligo(L-lactic acid) prepared by thermal dehydration of L-lactic acid, Pluronic$\^$TM/(PN) and dodecanedioic acid as carboxyl/hydroxyl adjusting agent. This polycondensation proceeded by catalysis of stannous oxide to give the multiblock copolymers with high molecular weight and wide range of compositions. Polymer film was prepared by casting the chloroform solution of the multiblock copolymers having different composition. The multiblock copolymers having relatively high contents of poly(L-lactide) were melt spun into filaments which were subsequently drawn at 60$^{\circ}C$. The copolymer films and the filaments showed an improved flexibility due to the incorporation of the soft segments.

• Mycobiology
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• 제33권4호
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• pp.210-214
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• 2005

More than 120 isolates of lactic acid bacteria obtained from Kimchi was screened for antifungal activity against Aspergillus fumigatus. Approximately 10% of the isolates showed inhibitory activity and only 4.16% (five isolates) exhibited strong activity against the indicator fungus A. fumigatus. The five isolates showed a wide rang of antifungal activity against A. flavus, Fusarium moniliforme, Penicillium commune, and Rhizopus oryzae. They were identified by 16S rDNA sequencing as Lactobacillus cruvatus, L. lactis subsp. lactis, L. casei, L. pentosus, and L. sakei. The effect of Lactobacillus on mycelial growth and fungal biomass as well as its ability to produce toxic compounds were determined. The results indicate that the three species, Lactobacillus casei, L. lactis subsp. lactis, and L. pentosus, are active against A. fumigatus.

• Asian-Australasian Journal of Animal Sciences
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• 제18권11호
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• pp.1582-1588
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• 2005

This study aimed to evaluate the effects of silage additives on the fermentation qualities and residual mono- and disaccharides composition of silages. Forage Oats (Avena sativa L.) and Italian Ryegrass (Lolium multiflorum Lam.) were ensiled with glucose, sorbic acid and pre-fermented juice of epiphytic lactic acid bacteria (FJLB) treatments for 30 days. In both species grass silages, although the respective controls had higher contents of butyric acid (20.86, 33.45g $kg^{-1}$ DM) and ammonia-N/total nitrogen (100.07, 114.91 g $kg^{-1}$) as compared with other treated silages in forage oats and Italian ryegrass, the fermentation was clearly dominated by lactic acid bacteria. This was well indicated by the low pH value (4.27, 4.38), and high lactic acid/acetic acid (6.53, 5.58) and lactic acid content (61.67, 46.85 g $kg^{-1}$ DM). Glucose addition increased significantly (p<0.05) lactic acid/acetic acid, and significantly (p<0.05) decreased the values of pH and ammonia-N/total nitrogen, and the contents of butyric acid and volatile fatty acids as compared with control, however, there was a slightly but significantly (p<0.05) higher butyric acid and lower residual mono- and di-saccharides as compared with sorbic acid and FJLB additions. Sorbic acid addition showed the lowest ethanol, acetic acid and ammonia-N/total nitrogen, and highest contents of residual fructose, total mono- and di-saccharides and dry matter as well as high lactic acid/acetic acid and lactic acid content. FJLB addition had the lowest pH value and the highest lactic acid content, the most intensive lactic acid fermentation occurring in FJLB treated silages. This resulted in the faster accumulation of lactic acid and faster pH reduction. Sorbic acid and FJLB additions depressed clostridia or other undesirable bacterial fermentation, thus this decreased the water-soluble carbohydrates loss and saved the fermentable substrate for lactic acid fermentation.

• KSBB Journal
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• 제25권3호
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• pp.244-250
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• 2010

약용식물인 도꼬마리 추출물을 사용하여 유산균을 이용한 단일 및 복합배양을 통하여 새로운 기능성 물질의 생산을 검토하였다. 도꼬마리 추출물의 유산발효 시 단일배양 결과에서 유산생산을 통해 대체로 잘 증식하는 것이 확인되었으며, H. pylori의 항균 활성은 단일배양보다 복합배양 시 항균활성이 아주 우수하였다. 항균성 물질의 분리는 $C_{18}$ Seppak cartridge에 흡착시켜 30% methanol 용출획분에서 항균성물질이 확인되었으며, TLC로 분석한 결과 $R_f$ 0.46의 위치에서 항균성 물질을 확인하였다. 도꼬마리 유산발효액의 항산화활성은 총 polyphenol 함량 및 radical 소거능을 검토하였으며, 그 결과 총 polyphenol 함량은 미발효시에 비해 도꼬마리 추출물의 저농도에서 단일배양의 경우 2~4배 증가하였으며, Lactobacillus brevis KCTC 3498과 Lactobacillus helveticus KCTC 3545를 복합배양한 경우 1 mg/mL 첨가농도에서 polyphenol이 가장 높게 나타났다. Radical 소거능은 도꼬마리 추출물을 0.1 및 0.5 mg/mL로 첨가하여 발효하였을 때 30~40%의 scavenging이 확인되어 발효를 하지않았을 때 (25%)보다 발효를 하였을 때 높아지는 것으로 나타났다. 특히 Lactobacillus casei KCTC 3109의 경우 0.1 mg/mL의 농도에서 70%의 scavenging을 나타내었다. 이들 결과로부터 도꼬마리 추출물의 유산발효는 미발효시에 비해 Helicobactor pylori에 대한 항균활성물질의 생산과 기능성물질인 항산화물질의 생산성이 우수하다고 사료되었으며 천연한약재의 발효를 통한 천연물 신약 등 신기능물질의 생산가능성을 확인하였다.

• 폴리머
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• 제25권3호
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• pp.385-390
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• 2001

oxyethylene/oxypropylene 공중합체의 존재하에 L-lactide를 중합시킴에 의해 poly(L-lactic acid) (PLLA) (A)와 polyether (B)로 이루어진 A-B-A block copoly(ester-ether)를 합성하였으며, 이들 블록 공중합체는 세그멘트를 도입함에 의해 PLLA에 유연성이 부여되었고, 표면에서의 미세상분리 구조로 인한 항혈전성의 개질을 확인하기 위하여 AFM사진을 관찰한 결과, PLLA와 비교하여 블록 공중합체는 필름표면의 요철성이 현저하게 저하하여 매끄러운 것을 확인하였으며 따라서, 표면의 요철이 항혈전성의 증가와 깊은 관계가 있음을 확인하였다.

• 폴리머
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• 제24권3호
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• pp.431-436
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• 2000

폴리락트산의 열적 안정성과 기계적 물성을 개선하고자 측쇄에 벤젠고리를 함유한 천연 $\alpha$-히드록시산인 만델린산(mandelic acid)과 L-락트산을 직접 용액 축중합법으로 공중합체를 합성하고 그 열적, 물리적 성질 등을 조사하였다. 합성된 공중합체는 무정형이었으며, 만델린산의 함량이 증가할수록 유리전이온도와 분해개시온도가 상승함을 열분석을 통해 알 수 있었다. 또한 만델린산을 5, 10 wt% 함유한 공중합체의 필름의 경우 그 기계적 성질이 다소 향상된 결과를 얻었다.

• 한국축산식품학회지
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• 제24권3호
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• pp.266-272
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• 2004

본 연구는 gelatin의 생산공정에서 각종 산 처리가 최종 gelatin의 품질에 어떤 영향을 주는지를 평가함으로써 양질의 gelatin을 생산하는데 기초를 제공하고자 하였다. Gelatin gel의 물성은 lactic acid로 처리한 gelatin이 높은 hardness, cohesiveness, brittleness를 나타내었고 다음으로는 citric acid, acetic acid 순으로 나타났다. Gelatin의 색도는 citric acid, 처리한 gelatin이 acetic acid나 lactic acid로 산침한 젤라틴 보다 높은 명도를 나타냈다. a-value는 acetic acid로 산침한 gelatin이 가장 높게 나타났으며 황색도를 나타내는 b-value는 lactic > acetic acid > citric acid 순으로 높게 나타났다. Gelatin의 점도를 측정한 결과 전단속도(shear rate)에 대한 전단응력(shear stress)의 관계는 모두 전단속도가 증가함에 따라 전단응력이 증가하는Newton성 유체로 판단되었다. 그 기울기는 acetic acid로 산침한 것이 가장 높게 나타났으며 lactic acid, citric acid 순으로 높게 나타났다. Gelatin내의 hydroxyproline 함량을 살펴보면 acetic acid(0.186 g/100 g sample)로 가장 높은 수치를 나타나며 다음으로 lactic acid, citric acid 순으로 나타났다. 그러나, sample중 crude protein 함량을 비교하면 acetic acid(68.74%), lactic acid(80.08%), citric acid(85.47%)로 나타났다. 이것은 gelatin의 열수 추출시 가장 작게 용출된 acetic acid가 가장 높은 collagenous connective tissue 함량(1.35 g/100g)을 나타내었다.

• 한국식품영양학회지
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• 제14권2호
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• pp.126-131
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• 2001

Microbiological, pH and sensory evaluations of pork loins treated with lactic acid cultures (Lactococcus lactis subsp. lactis ATCC 11454 grown in 10% milk solids) during storage at 4$^{\circ}C$ were assessed. Pork loins were immersed in solutions containing 3.96 log units, 4.10 log units, or 4.23 log units of individual lactic acid cultures for 2 min. Pork loins treated with lactic acid cultures had a inhibitory effect (P<0.05) on the growth of aerobic palate counts during storage of 3 days at 4$^{\circ}C$. Pork loins treated with lactic acid cultures during storage of 3 days at 4$^{\circ}C$ significantly (P<0.05) decreased pH values compared to those of controls. Sensory evaluations for odor and appearance of pork loins treated with lactic acid cultures during storage of 9 days at 4$^{\circ}C$ were a "liked less" to "typical" category compared to those of controls.