• Journal of the Korean Society of Food Culture
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• v.16 no.4
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• pp.354-360
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• 2001

A Lactic acid bacterium for barley bread was isolated from barley powder and was identified as Enterococcus sp. It was used as a starter for barley bread and quality of bread was compared with the bread prepared by conventional starter 1. The pH of bread making process using Lactobacillus sanfrancisco starter was the lowest among tested starters. while the titratable acidity(TTA) of the strain was the highest, followed by Enterococcus sp.. 2. In valorimeter value(v/v), control was 70, but dough using all starter was 60. The peak time and stability of dough using Lactobacillus sanfrancisco were the highest among tested starters. 3. Extensibility of dough using Enterococcus sp. was the highest among tested starters, followed by Lactobacillus sanfrancisco. Proper extensibility and maximum resistance were observed in Lactobacillus sanfrancisco.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5693-5699
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• 2014

The influence of the flour types, including bread flour and cake flour on sourdough preparation was investigated. As starters, mixed probiotic microorganisms, including Bifidobacterium longum KCTC 5734, Enterococcus faecium KCTC 13410, and Lactobacillus acidophilus KCTC 3925, or Saccharomyces cerevisiae fermented separately for 15h at $30^{\circ}C$, were combined and then fermented for 10h at $30^{\circ}C$. The combined process with cake flour showed a 100-fold and two-fold increase in [$H^+$] and titratable acidity, respectively. This was also reflected in the viable cell counts and lactate concentration in sourdough. These results show that bread flour and cake flour may be useful for the production of sourdough.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.168-172
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• 2017

In this study, the fermentative characteristics of rye sourdough fermented with Omija extract were investigated. The pH and total titratable acidity, numbers of yeast and lactic acid bacteria, and expansion rate were measured. While the pH of Omija rye sourdough decreased from 5.60 to 3.86, the total titratable acidity significantly increased from 2.39 to 8.50 with fermentation time (p<0.05). The numbers of yeast and lactic acid bacteria significantly increased for 18 h of fermentation period (p<0.05). The expansion rate of Omija rye sourdough showed a maximum of 183%, more than 47% more than the highest value of rye sourdough (129%). These results suggest that the application of Omija extract for making sourdough could be a good way to decrease the sanitary risk especially for early stage of sourdough fermentation. In addition, Omija rye sourdough could contribute to improvement of baking quality such as volume increase and flavor improvement of rye bread.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.471-481
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• 2016

The primary objective of this study was to investigate the effects of the bacteriocin-producing heterofermentative lactic acid bacteria (LAB) and acid-resistant yeast isolated from Mukeunji, a Korean ripened kimchi on shelf-life extension and quality improvement of sourdough. According to gene sequence analysis the heterofermentative LAB that showed the antimicrobial activity against bread-spoilage Bacillus strains were identified as Leuconostoc mesenteroides LAS112, Lactobacillus brevis LAS129, and L. mesenteroides subsp. dextranicum LAB137. In addition, the yeasts that were able to grow at acidic pH were identified as Pichia membranifaciens YS05, Pichia fermentans YS19, and Pichia anomala YS26. During sourdough fermentation the levels of acetic acid and bacteriocin produced by L. brevis LAS129 strain were higher than those of L. mesenteroides LAS112 and L. mesenteroides subsp. dextranicum LAS 137 strains, whereas LAS112 strain produced the highest levels of lactic acid. The maximum bacteriocin activity (640 AU/g) against Bacillus subtilis ATCC 35421 was obtained in sourdough fermented by mixed culture of L. brevis LAS129 and P. membranifaciens YS05 or P. anomala YS26. After 24 h of fermentation at $30^{\circ}C$, the viable cell counts of LAS129 ($10^9CFU/g$) in sourdough were higher than those of the YS05 or YS26 ($10^7CFU/g$). Meanwhile, the viable cells of bread-spoilage strain in sourdough fermented with these strains were significantly (P < 0.05) lower than the control group.

• Journal of Microbiology and Biotechnology
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• v.29 no.11
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• pp.1729-1738
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• 2019

In sourdough fermentation, lactic acid bacteria perform important roles in the production of volatile and antimicrobial compounds, and exerting health-promoting effects. In this study, we report the probiotic properties and baking characteristics of Lactobacillus plantarum SPC-SNU 72-2 isolated from kimchi. This strain is safe to use in food fermentation as it does not carry genes for biogenic amine production (i.e., hdc, tdc, and ldc) and shows no β-hemolytic activity against red blood cells. The strain is also stable under simulated human gastrointestinal conditions, showing tolerance to gastric acid and bile salt, and adheres well to colonic epithelial cells. Additionally, this strain prevents pathogen growth and activates mouse peritoneal macrophages by inducing cytokines such as tumor necrosis factor-α, interleukin (IL)-6, and IL-12. Furthermore, the strain possesses good baking properties, providing rich aroma during dough fermentation and contributing to the enhancement of bread texture. Taken together, L. plantarum SPC-SNU 72-2 has the properties of a good starter strain based on the observation that it improves bread flavor and texture while also providing probiotic effects comparable with commercial strains.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.501-509
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• 2021

The increasing demand for baked products has given a boost to research on isolation and selection of novel yeast strains with improved leavening activity. Twelve sourdough samples were collected from several localities of the Fez region in Morocco. The pH and total titratable acidity (TTA) values of these samples varied from 3.03-4.63 and 14-17.5 ml of 0.1 N NaOH/10 g of sourdough, respectively, while yeast counts ranged from 5.3 6.77 Log CFU/g. Thirty-two yeast isolates were obtained and evaluated for their leavening ability. Out of all isolates, four yeasts molecularly identified as Saccharomyces cerevisiae (three strains) and Kluyveromyces marxianus (one strain) showed highest specific volumes of 4.69, 4.55, 4.35 and 4.1 cm³/g, respectively. These strains were further assessed for their tolerance to high concentrations of salt, sugar, elevated temperatures, and low pH conditions. K. marxianus showed higher resistance than the S. cerevisiae. Thus, Moroccan sourdoughs harbor technologically relevant yeasts that could be used as potential starters for bread preparation.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1736-1743
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• 2017

Sourdough is made by fermentation of dough by lactic acid bacteria (LAB) and yeast to improve bread properties like volume, flavor, and texture. A Korean traditional sourdough was made by fermenting rice flour with rice wine (makgeolli) and used to make sponge-like bread (jeung-pyun). The aim of this study was to investigate the microbial diversity of makgeolli products and their influence on the organoleptic quality of jeung-pyun. Three commercial makgeolli were tested for jeung-pyun production, with each product exhibiting varied dough swelling rates and organoleptic qualities, and among them, J-product was ranked highest in texture and taste. Microbial analysis of the three makgeolli also showed a big difference in their population and diversity. J-product had the highest LAB and yeast counts, and the predominant species were Lactobacillus casei, Lactobacillus brevis, Leuconostoc pseudomenteroides, and Saccharomyces cerevisiae. Using J-product, sourdough was fermented at $25^{\circ}C$, $30^{\circ}C$, and $35^{\circ}C$, and the microbial growth in and textural properties of jeung-pyun were examined by instrumental and sensory tests. At high temperature ($35^{\circ}C$), the rates of dough swelling and acidification were fast due to rapid microbial growth mainly caused by LAB, resulting in a short leavening time and soft and sour jeung-pyun. Sensory tests showed consumer preference for the soft and mild-sour jeung-pyun. This study shows that LAB in makgeolli play key roles in production of jeung-pyun, influencing the textural and sensory properties. For the production of high-quality jeung-pyun, development of LAB starters with high gas productivity and low acidity and establishment of an optimal fermentation procedure for rice dough are necessary.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1180-1185
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• 2004

This study was conducted to investigate the optimum conditions for the medium composition after isolating and identifying yeast and lactic acid bacteria from sourdough. It was found that the best quality lactic acid bacterium with acid product and flavor was identified as Leuconostoc species among isolated 115 lactic acid bacteria, the best Quality yeast with good fermentation and flavor was identified as Saccharomyces species among isolated 8 yeast. While the microbial growth with glucose or sucrose as sugar source was good, it was, selected that sucrose which is using commercially is better than glucose. The growth of lactic acid bacterium ; was good with 1％ added sucrose whereas yeast needed more growth. Additionally, the medium for the optimum 1 growth of the yeast was composed of 0.5％ wheat flour, 0.5％ peptone and 3％ sucrose, whereas lactic acid bacterium was composed of 0.5％ wheat flour and 1％ sucrose without peptone.

• Journal of Power System Engineering
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• v.11 no.2
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• pp.5-11
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• 2007

액화천연가스(LNG : Liquified Natural Gas)는 연료로 사용하기 위하여 기화하는 과정을 거치게 되는데 기화하는 방식에는 해수에 의한 기화와 공기에 의한 기화의 두 가지 방식으로 나뉘게 된다. 해수에 의한 기화는 LNG 인수기지에서 대량의 LNG를 NG로 기화하기 위하여 사용하며, 공기에 의한 기화는 LNG 위성기지에서 사용처에 적합한 온도를 얻기 위해서 일반적으로 많이 사용하고 있는 공기식 기화기를 이용하여 기화를 하는 방식을 취하고 있다. LNG가 NG로 기화하는 과정에서 1kg당 200kcal의 냉열을 외부로 방출하고 있으며, 이러한 냉열의 방출로 인하여 공기식 기화기의 표면에 결빙현상을 발생시킨다. 또한 현재 사용하고 있는 기화기는 $2{\sim}3$개의 기화기를 연결하여 사용하고 있어 그 비용의 손실이 크다고 할 수 있다. 그리하여 본 연구는 최근 사용빈도가 증가하고 있는 공기식 기화기에 관한 것으로 작동유체는 실제 LNG와 특성이 비슷한 초저온 액화가스인 $LN_2$를 사용하였다. 이번 연구에 사용된 변수는 다음과 같다. 첫째, 각각의 기화기의 길이를 4000mm, 6000mm, 8000mm으로 하였고 핀의 type을 finless, 4fin, 8fin으로 하여 적용하였다. 두 번째는 봄, 여름, 가을, 겨울철에 따른 기화기의 성능을 알고자 각각의 계절별 온도와 습도를 적용하였다. 마지막으로 계절별 풍속과 실험을 하는 시간 동안의 유량을 알고자 압력을 1 bar로 적용하였다. 그리하여 이번 연구의 목적으로는 각각의 변수를 통하여 실험을 진행 한 후 vaporizer type과 길이에 대한 최적의 성능을 가지는 기화기에 대한 자료를 제시하고자 한다.기성분은 균주에 따른 약간의 차이가 있었으나 경향은 비슷하게 나타났다. 이상의 결과 알코올 발효 균주에 따른 참다래 와인의 이화학적 품질특성에는 큰 차이가 없었으나 고급알코올함량을 비교하였을 때 Sacch. cerevisiae Wine 3이 와인제조에 가장 적합한 것으로 평가되었다.장 낮은 값을 나타내었으며, 홍국의 함유량이 증가할수록 유의적으로 증가하였다. b값은 CSB가 가장 낮은 값을 나타내었으며, 홍국의 함유량이 증가할수록 유의적으로 증가하였다. 물성측정 결과 경도와 응집성은 각 시료들 간의 유의적인 차이가 나타나지 않았다. 탄력성과 부서짐성은 CSB가 가장 낮았으며, 홍국의 함유량이 증가할수록 증가하였다. 점착성은 SDB1이 가장 낮았으며, 홍국의 함유량이 증가할수록 증가하였다. 관능검사 결과 기공의 균일성은 SDB1이 가장 균일한 것으로 나타났으며, 색은 홍국의 함유량이 증가할수록 높게 나타났다. 경도, 탄력성, 단맛 및 신맛 등은 홍국 함유량이 증가할수록 증가하는 것으로 나타났다. 이취는 SDB1이 가장 적게 나는 것으로 나타났으며, 전반적인 기호도는 SDB1이 가장 높았다. 따라서 홍국을 10% 첨가한 sourdough starter를 3일 동안 발효한 후 반죽에 첨가하여 sourdough bread를 제조할 때 품질이 가장 우수한 제품을 얻을 수 있었다.생수와 여러 물질의 혼합용액의 온도가 장에 끼치는 자극에 차이가 있지 않나 추측되며 이에 관한 추후 연구가 요망된다. 총대장통과시간의 단축은 결장 분절 모두에서 줄어들어 나타났으나 좌측결장 통과시간의 감소 및 이로 인한 이 부위의 통과시간 비율의 저하가 가장 주요하였다. 이러한 결과는 차가운 생수 섭취가 주로 결장 근위부를 자극하는 효과를 발휘하는 것이 아닌가

• Investigative Magnetic Resonance Imaging
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• v.11 no.1
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• pp.39-48
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• 2007

Purpose : To determine the diagnostic accuracy of four different sequences : moderately T2 weighted, two heavily T2-weighted single shot turbo spin-echo sequence and breath-hold axial-2D balanced turbo field-echo sequence(bFFE) for characterization of focal lesions. Materials and Methods : During the 3-month period between June and August 2005, seventy-six patients were proved to have ninety-three focal hepatic lesions on MR imaging. The patients consisted of 49 men and 27 women (age range, 15-75 years; mean age, 56.23 years). All MR images were acquired on a 1.5-T MR using the following sequences: 1. A breath-hold axial T2-weighted single shot turbo spin-echo sequence, 2. a breath-hold axial-2D balanced turbo field-echo sequence. Two radiologists performed quantitative analysis. Another radiologist measured the lesion-to-liver contrast-to-noise ratio at the region-of-interest in the four sequences. Results : There was no significant difference in inter-observer variability between the four sequences. The accuracy for both cyst and malignancy of moderate T2 weighted MRI (echo time: 80 msec) was also highest. There was significant difference for lesion characterization between moderate T2 weighted MRI and balanced steady state procession (p-value: 0.004) in the second reader. For longer echo time, the CNR of cystic lesions were markedly increased in comparison to lesions of other component. Conclusion : The accuracy and inter-observer variability of single shot turbo spin echo T2 weighted sequence was higher than bFFE. Although there was no statically significant difference, moderate T2 weighted MRI (echo time: 80 msec) was more accurate than heavily T2 weighted sequence (echo time: 300 msec). If the results for lesion characterization is equivocal in TE 80, the addition of heavily T2 weighted MRI (echo time: 180 msec) can be helpful.