• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.155-160
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• 1979

Mechanical agitation in fermentation process enhances the fermentation activity of microbes by means of oxygen supply and frequent collision with substrate. However, the fermentation activity of microaerophilic bacteria is inhibited by the excess oxygen resulted from the mechanical agitation. On this account, a a strain of Lactobacillus bulgarius was cultured to know the inhibition effect of the mechanical agitation and determine the optimum conditions for tile process of lactic acid fermentation. The growth rate of L. bulgaricus and the consumption rate of tile substrate revealed an identical pattern in changes. The two rates were constant in the range of the modified Reynolds number of $1\times10^5\;to\;5\times10^5$ while they showed linear increase in the range of the modified Reynolds number of $1\times10^5\;to\;10\times10^5$. Under the conditions of the modified Reynolds number more than $10\times10^5$, the both rates decreased. At the modified Reynolds number of $10\times10^5$, the maximum specific growth rate and the saturation constant of L. bulgaricus were 0.58/hr and 6.74g/l, respectively.

• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.291-298
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• 2012

One of the main microorganisms causing diarrheal diseases is Campylobacter jejuni. Purslane or Portulaca oleracea is an edible plant containing polyphenols that has been widely used as a folk remedy for treatment of diarrhea for a long time. This study was performed to investigate the antimicrobial activity of fermented P. oleracea extracts made with probiotics and plant-origin lactic acid bacteria(PLAB) isolated from P. oleracea against C. jejuni. Lactobacillus rhamnosus, L. acidophilus, L. bulgaricus, L. delbrueckii, L. plantarum, Leuconostoc mesenteroides and Bifidobacterium longum were applied to P. oleracea to make a fermentation broth of purslane. Leuconostoc mesenteroides and the lactic acid bacteria isolated from P. oleracea grew best in the fermentation broth of P. oleracea extracts when the broth was combined with 2% yeast extract, 1% peptone, and 0.05 to 1% potassium phosphate. The number of viable cells in the fermentation broth containing purslane extracts after 48 hours increased to $1{\times}10^{12}\;CFU/m{\ell}$ and remained at $1.3{\times}10^{10}\;CFU/m{\ell}$ after refrigeration for 2 weeks. The pH and acidity of purslane-fermented broth after 48 hours of fermentation was 3.7 and 3.14, respectively, which show that the fermentation broth was within the range of the general standards of fermented dairy products. The antimicrobial activity of the fermented P. oleracea extracts was determined using the liquid culture method. The 10 $mg/m{\ell}$ concentration of the fermented P. oleracea extract made with Leuconostoc mesenteroides and the lactic acid bacteria isolated from purslane showed the strongest antimicrobial activity against C. jejuni. The fermentation broth of purslane with the probiotics retarded the growth of C. jejuni for 48 hours at $42^{\circ}C$.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.398-403
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• 2013

To manufacture the fermented tea with hygienic quality, green tea was fermented using Bacillus subtilis, Saccharomyces cerevisiae and Lactobacillus bulgaricus and mineral composition, total amino acid content and antioxidative activity changes were evaluated during the fermentation period. Minerals detected in the fermented tea, the Ca, Fe, Zn, Mg and Mn minerals were detected. Ca and Mg are relatively large compared to other mineral content. Total amino acid content of the control was 3.57%, but total amino acid of fermented teas were higher (3.68~3.85%) during fermentation 20 days. Metal chelating activity of control was 55.11%, Metal chelating activity of the fermented tea using B. subtilis was the highest. In reducing power, O.D. value of the control was 2.27, three kinds of fermented tea were lower than that of control. The fermented teas increased lipid peroxidation inhibition compared to the blank test.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1388-1393
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• 1998

Traditional Andong sikhe was produced by fermenting L. bulgaricus LBS 47 and S. cerevisiae SCS 5. The changes of nitrogen compound and amino acid during fermentation and storage were investigated. Crude protein was increased until 4days, the main fermentation period. Amino form nitrogen increased up to 37.50 mg% at the 2nd day of fermentation and the product tasted best at this time. Water soluble and salt soluble protein decreased during fermentation. Proline and aspartic acid were the two major free amino acids. The free methionine increased while the free lysine decreased in the process of fermentation. The amino acids of water soluble protein and salt soluble protin were totally 17 kinds. The major amino acids of water soluble and salt soluble protein were glutamic acid and aspartic acid. The arginine content of salt soluble protein increased as the fermentation proceeded.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.8
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• pp.1073-1078
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• 2011

Changes of antioxidative components and activity of fermented tea manufactured by Bacillus subtilis, Saccharomyces cerevisiae, and Lactobacillus bulgaricus were evaluated during the fermentation period. The ascorbic acid content in the fermented tea was relatively lower (43.62~62.84 mg%) than that of green tea (66.74 mg%) during the entire fermentation period. The tea fermented by L. bulgaricus, which had the least contact with air, showed less change in ascorbic acid content. The polyphenol content of green tea was 14.88%, whereas that of fermented tea was 11.54~14.12% and it decreased during the fermentation period. The amount of flavonoids in green tea was 7.78 mg%, whereas that of fermented tea was 4.33~7.88 mg%. DPPH radical scavenging activity and ABTS reducing activity of green tea were 87.47% and 203.22 AEAC mg% (ascorbic acid equivalent antioxidant capacity), respectively, whereas those of fermented tea were lower than green tea. Results indicated that the antioxidative components and activity of fermented tea were lower than those of green tea during the fermentation period. But, when the sensory and hygienic quality are considered, fermented tea can be one of the higher quality tea products on the market.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.532.1-532
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• 1986

유산균이 생성하는 polysaccharide 에 관한 연구의 일환으로서 L. casei YIT 9018 SKD-0007, L. bulgaricus SKD-0003, sir. faecalis SKD-1007, str. thermophilus SKD- 1005, str. thermophilus 510 SKD-1006등을 탈지유에 배양하면서 polysaccharide 생성에 의한 배양액의 점도 변화를 검토하였다. 이러한 다당류가 Antitumor로서의 활성과 제암효과를 가지며 인체내의 생리효과를 고양시킨다고 보고되어 있는바 다당류가 최대로 생성되는 조건을 찾는 것을 본 실험의 목적으로 하였다. 다당류의 생성을 측정하는 방법으로서 배지로는 10% 환원탈지유와 12% 환원전지유를 선택하였으며 Brookfield Viscometer를 사용하여 배양액의 점도를 경시적으로 측정하였다. 시험균 중에서 str. thermophilus 510 SKD-1006이 가장 높은 점도를 나타내었는데 41$^{\circ}C$ 배양 5일째에 5000 cps였고 다른균에 비해서 1000cps이상 높았다. 접종량이 증가할수록 점도도 증가하였으며 14%이상의 탈지유 농도에서는 7000cps를 나타냈다. 탈지유와 전지유 배양액 모두 의가소성 유체의 유동 양식을 나타내었는데 12% 환원전지유 배양액은 최대점도값이 2500 cps에 불과하였으며 배양 2일째에 최대점도 값에 도달하여 그 이후로 급격한 감소현상을 보였다.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.216.3-217
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• 2003

본 연구에서는 우유에 탈지분유 또는 4종의 쌀을 각각 2%(w/v)첨가하여 커드상의 요구르트를 만들고, 대조군(우유로만 만든 요구르트)과 비교하여 쌀의 첨가가 젖산균의 산생성 및 커드상 요구르트의 품질(관능성, 저장성에 미치는 영향을 조사하였으며, HPLC를 이용하여 몇 가지 유기산을 분석하였다. 쌀의 첨가로 젖산균의 산생성이 대조군보다 촉진되었는데 현미의 촉진효과가 가장 현저하였다. 접종된 4종의 젖산균(Lacttobacillus 3종, Leuconostoc 1종) 중에서는 Lenc. mesenteroides 와 L. bulgaricus 의 산생성도가 높았다. HPLC에 의한 유기산 분석의 결과를 보면 우유나 2% 현미를 첨가한 우유에 L. bulgaricus를 접종하여 24시간 발효하는 동안 lactic acid 는 젖산균에 의해 생성되어 그 양이 현저하게 증가하였으나, 우유 중에 들어있는 citric acid 는 젖산균에 의해 이용되어 그 양이 현저히 감소하였다. 커드상 요구르트의 관능성은 쌀의 첨가로 표준시료보다 다소 저하되었으며, 쌀 첨가시료 중에서는 통일벼 참가시료가 다른 시료보다 우수하였다. 커드상의 요구르트를 2주일 간 5$^{\circ}C$냉장고에 저장하는 동안 산생성과 pH, 생균수에 거의 변화가 없어 저장성은 매우 우수한 것으로 나타났다.

• KSBB Journal
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• v.32 no.3
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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.

• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.587-592
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• 1991

The curd yogurt was prepared from milk or milk added with skim milk powder or four types of rice powder. Acid production by lactic acid bacteria in milk containing additive of 2% (w/v) was investigated and quality of curd yogurt (sensory property and keeping quality) was examined. Some organic acids in curd yogurt were analyzed by HPLC. Four types of rice powder, particularly brown rice, stimulated acid production by lactic acid bacteria more than control (milk yogurt). Among four organisms tested, Leuconostoc mesenteroides and Lactobacillus bulgaricus produced more acid than L. casei and L. delbrueckii. HPLC analysis of organic acids in curd yogurt showed that the amount of lactic acid markedly increased during the fermentation by L. bulgaricus for 24 hours while the amount of citric acid markedly decreased. Addition of rice powders to milk slightly reduced sensory property of curd yogurt. Among four types of rice powder tested, tongil rice added sample showed better sensory acceptability than other samples. When curd yogurt was kept at $5^{\circ}C$ for two weeks, acidity and number of viable cells of curd yogurt were not changed.

• The Korean Journal of Food And Nutrition
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• v.15 no.1
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• pp.42-50
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• 2002

This experiment was carried out to investigate the effect of Maesil extract on the acid production and growth of yoghurt starter in the skim milk medium. The Maesil extract was added to skim milk medium fur 1% to 9% and the medium was fermented by single or mixed culture of 4 types of lactic acid bacteria(Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus, bulgaricus, Lactobacillus casei). The chemical composition of Maesil, the changes in acid production (titratable acidity, pH) and number of viable cells of the medium during lactic fermentation in skim milk added with Maesil extract, and the keeping quality of curd yoghurts containing Maesil extract have determined. The composition of Maesil were 0.4% crude ash, 4.1% dietary fiber, 4.66%l citric acid, 0.264% total sugars and 405.34mg% vitamin C. The addition of Maesil extract stimulated the acid production and propagation of the lactic acid bacteria. Among the treatments tested, the addition of 3% Maesil extract with the mixed culture of Streptococcus thermophilus, Lactobacillus acidophilus and Lactobacillus casei produced the highest amount of acid(1.23%) and showed the highest number of viable cell counts(3.6$\times$10$^{11}$ cfu/mL). When the curd yoghurts containing 3% Maesil extract with the mixed culture of the lactic acid bacteria were kept at 4$^{\circ}C$ and 2$0^{\circ}C$ for 30 days, it was showed that the changes of titratable acidity, pH and number of viable cell counts of the lactic acid bacteria were not significantly different during storage. Therefore the keeping quality of the curd yoghurts adding 3% Maesil extract showed relatively good at the shelf-life.