• Journal of Dairy Science and Biotechnology
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• 제36권3호
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• pp.178-185
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• 2018

Kefir, which originates in the Caucasian mountains, is a cultured milk beverage produced by a combination of acidic and alcoholic fermentation. Kefir products are commonly used as food vehicles to deliver health-promoting materials including kefran and lactic acid bacteria to consumers. The aim of this study was to develop a freeze-dried starter culture without yeast and assess the suitability of kefir-like dairy products for the growth of lactic acid bacteria and the acidification of milk. Pasteurized whole milk (SNF 8.5%) stored at $25^{\circ}C$ was aseptically inoculated with starter cultures (0.002% w/v); it was kept at $25^{\circ}C$ until the pH attained a value of 4.6. Ten grams of the kefir-like product sample was diluted with 90 mL of 0.15% peptone water diluent in a milk dilution bottle, followed by uniform mixing for 1 min. Viable cells of Lactobacillus species were enumerated on modified-MRS agar (pH 5.2), with incubation at $37^{\circ}C$ for 48 h. Viable cells of Lactococcus species were enumerated on M17-lactose agar, with incubation at $32^{\circ}C$ for 48 h. The pH attained a value of 4.6 after fermentation for 9 h 30 min (Starter 1), 9 h 45 min (Starter 2), and 12 h (Starter 3). The viable cell count of Lactobacillus sp. and Lactococcus sp. was initially $10^5{\sim}10^6CFU/g$; it increased significantly to $10^9CFU/g$ after 12 h of incubation. During the storage of the kefir-like products at $4^{\circ}C$ for 1 4 days, the total viable cell numbers were unchanged, but the pH decreased slightly. The consistency of the kefir products increased gradually during the storage. The organoleptic properties of the kefir products fermented using the new starter culture are more desirable than those of commercial kefir. These results suggest that the newly developed starter culture without yeast could be suitable for kefir fermentation.

• 한국미생물·생명공학회지
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• 제28권2호
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• pp.117-123
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• 2000

P. phosphoreum의 생존과 생체발광도는 온도에 의해 많은 영향을 받는다. 냉동 저장한 세포의 경우 glycerol의 보호 작용으로 세포농도와 생균수는 측정기간 동안 일정하게 유지된 반면 생체발광도는 glycerol 첨가 직후 급속히 감소하였으며, 저장 이후에도 감소된 생체발광도가 활성화되지 못하였다. 최적 생육온도인 $20^{\circ}C$의 경우 저장 초기 세포가 성장함에 따라 세포수의 증가를 보였으나 일정 시간 이후 세포 분해 현상으로 인하여 생균수 및 세포 집락수의 감소를 나타내었으며, 생체발광도는 저장 3일 이후 소멸되었다. 이와는 대조적으로 $4^{\circ}C$에 저장한 세포의 생체발광도는 저장 10일 동안 지속되어 가장 높은 생체발광 유지도를 나타내었으나 장기간 저온 저장으로 인하여 세포가 VBNC 상태에 돌입됨에 따라 총균수와 생균수는 일정한 반면 저장 10일 이후 세포 집락수의 급격한 감소를 나타내었으며, 저장 20일 이후 간균에서 구균으로 세포 형태상의 변화를 나타내었다. 이에 따라 세포 저장 시 접종원의 농도를 달리하여 VBNC 상태와 생체발광도의 관련성을 조사한 결과 VBNC 세포가 증가할수록 생체발광도의 감소를 나타내었다. 따라서 VBNC 세포를 감소시키기 위하여 세포를 고정화하여 저장한 결과 별도의 활성제 없이 실온에서 다시 활성화되어 고정화하지 않은 세포에 비해 2.3배 높은 생체발광유지도를 나타내었으며, 저온저장에 따른 platebility 소실과 세포 응축현상이 나타나지 않았다. 이러한 결과는 세포의 고정화 방법을 이용하여 $4^{\circ}C$에서도 세포의 생존 및 생체발광 유지도를 향상시킬 수 있으며, 동결 건조법의 단점을 보완해 줄 것으로 생각된다.

• Osong Public Health and Research Perspectives
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• 제8권6호
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• pp.389-396
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• 2017

Objectives: To circumvent the limitations of the current golden standard method, colony-forming unit (CFU) assay, for viability of Bacille Calmette-$Gu{\acute{e}}rin$ (BCG) vaccines, we developed a new method to rapidly and accurately determine the potency of BCG vaccines. Methods: Based on flow cytometry (FACS) and fluorescein diacetate (FDA) as the most appropriate fluorescent staining reagent, 17 lots of BCG vaccines for percutaneous administration and 5 lots of BCG vaccines for intradermal administration were analyzed in this study. The percentage of viable cells measured by flow cytometry along with the total number of organisms in BCG vaccines, as determined on a cell counter, was used to quantify the number of viable cells. Results: Pearson correlation coefficients of FACS and CFU assays for percutaneous and intradermal BCG vaccines were 0.6962 and 0.7428, respectively, indicating a high correlation. The coefficient of variation value of the FACS assay was less than 7%, which was 11 times lower than that of the CFU assay. Conclusion: This study contributes to the evaluation of new potency test method for FACS-based determination of viable cells in BCG vaccines. Accordingly, quality control of BCG vaccines can be significantly improved.

• 한국식품저장유통학회지
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• 제17권5호
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• pp.602-607
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• 2010

어수리의 실용적인 활용방법을 모색하기 위하여 어수리 분말을 첨가하여 생면을 제조하고. 이들 면의 품질특성과 저장성을 비교 검토하였다. 어수리 분말의 첨가량이 증가 할수록 국수의 중량, 부피 및 수분흡수율이 감소하였다. 어수리 분말의 첨가량이 증가할수록 국수 국물의 탁도와 조리중 고형분 손실량이 대조구에 비해 낮았다. 어수리 분말 첨가에 의해 생면의 명도(L)와 적색도(a)는 감소하였으며, 황색도(b)는 증가하였다. 어수리 분말 첨가에 의해 국수의 기호성은 증가하였으며, 0.6%첨가 국수가 기호성 즉 맛, 조직감, 종합적기호도에서 가장 우수하였다. 총 폴리페놀 함량은 어수리 분말의 첨가량이 증가할수록 증가하였으며, 전자공여능은 대조구 22%, 어수리 분말 0.6%와 0.9%첨가구는 각각 40.22%와 49.42%이었다. 저장 중 미생물의 변화는 저장 6일째까지 대조구와 첨가구(0.3 - 0.6%)간에 뚜렷한 차이를 나타내지 않았으며, 저장 12일째 대조구, 0.3% 그리고 0.6%첨가구는 $10^6$ CFU/mL이었으나, 어수리 분말 0.9%첨가 국수는 $10^3$ CFU/mL이었다. 저장 중 pH의 변화는 대조구와 0.3%, 0.6%첨가구는 유사하였으나 0.9% 첨가구는 전 저장기간 동안 pH의 변화가 지연되었다.

• 한국식품저장유통학회지
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• 제16권6호
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• pp.804-809
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• 2009

최근, 저온 장시간 발효된 묵은지에 대한 소비가 증가하고 있다. 본 논문에서는, 저온($5^{\circ}C$)에서 46주 동안 발효된 묵은지의 pH, 산도, 유기산, 생균수, 아미노산, polygalacturonase (PG) 활성 등을 분석하였다. 10주 발효한 김치에서는 pH 4.1, 산도 0.99%를 나타낸 반면, 46주 발효한 김치에서는 pH 3.9, 산도 1.29%를 보였다. 한편, 10주에서 46주로 발효 기간이 증가하면서, 젖산, 젖산/초산비, Lactobacillus species/Leuconostoc species비 등은 증가한 반면, 호기성 세균, 효모, Lactobacillus species, Leuconostoc species, 유리아미노산, PG 효소 활성은 감소하였다.

• 한국식품조리과학회지
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• 제22권1호
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• pp.12-21
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• 2006

This study analyzed the characteristics of single-harvested pepper flakes and investigated the effects of the addition of red and green pepper flakes on the quality of various dressings. Moisture contents of red and green pepper flakes were $14.57{\pm}0.13%\;and\;11.86{\pm}0.12%$, capsaicinoids contents on a dry-weight basis were $207.91{\pm}6.68\;mg/100\;g\;and\;172.32{\pm}5.94\;mg/100\;g$, and total free sugars were $21.63{\pm}1.81%\;and\;12.49{\pm}0.56%$, respectively. ASTA color of red pepper flakes was $150.93{\pm}4.56$. Viable cell numbers of red and green pepper flakes were $3.9X10^4\;CFU/g\;and\;5.2X10^5\;CFU/g$, respectively. The pH values in French dressing and Italian dressing, with added red and green pepper flakes, were slightly increased, but not in American Caesar dressing. Acidity and viscosity weren't statistically different in the 3 kinds of dressings by the addition of red and green pepper flakes. The color difference $({\Delta}E^*_{ab})$ for the storage periods was calculated in each dressing and that of American Caesar dressing with added red pepper flakes was extremely high. Viable cell number in each dressing was maintained at 2 log CFU/g during the storage periods. The sensory characteristics during the storage periods were assessed by members of a trained panel, and showed that the color and pungency of red and green flakes increased the overall preference in the Italian dressing and American Caesar dressing.

• 동아시아식생활학회지
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• 제18권1호
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• pp.95-103
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• 2008

The aim of this study was to evaluate the physicochemical, microbial, and sensory characteristics, as well as antioxidative activities of yoghurts containing spirulina powder, during storage at 4$^{\circ}C$. The pH of the yoghurts decreased until the 9th day of storage, but significantly increased by the 12th day. Total acidity also increased until the 9th day of storage, and then significantly decreased by the 12th day. Sugar content did not change significantly (approximately 18 $^{\circ}Brix$). Viscosity(cP) increased until the 6th day of storage, but had decreased at the 12th day. The viable bacterial cell counts of the control group decreased during storage. In contrast, the viable cell counts of the spirulina containing samples increased until the 9th day, and then decreased by the 12th day of storage. Antioxidant activity decreased in all groups, but the changes in antioxidant activity were lower in the spirulina groups than in the control group. According to sensory evaluations, the samples presented no significant differences during storage. Based on the above results, the optimum concentration of spirulina was determined as 0.25%. Also, the period of circulation of yoghurt containing spirulina was estimated to be 9 days at 4$^{\circ}C$.

• 한국식생활문화학회지
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• 제30권6호
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• pp.757-765
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• 2015

The objective of this study was to determine the quality characteristics of fermenting mash and pasteurized ginseng Makgeolli added with different concentrations of ginseng powder. Total aerobic bacteria and lactic acid bacteria counts of mash added with 0, 1, 2, and 4% ginseng powder during 4 days of fermentation significantly increased, whereas yeast count decreased. Viable cell count remarkably decreased after pasteurization. Pasteurized 4% ginseng Makgeolli (4.30) showed a higher pH than 0, 1, and 2 % ginseng Makgeolli (4.09, 4.08, and 4.06, respectively) after 15 days of aging. After aging, amylase activity of pasteurized Makgeolli decreased, and 0% and 1% ginseng Makgeolli (22.35, $21.55^{\circ}Brix$) showed higher Brix content than 4% ginseng Makgeolli ($20.15^{\circ}Brix$). Before aging, alcohol contents of 0, 1, 2, and 4% pasteurized ginseng Makgeolli were 5.80, 5.50, 5.20, and 5.10%, respectively. After 15 days of aging, 0% ginseng Makgeolli (7.00) showed higher alcohol content than 1, 2, and 4% ginseng Makgeolli (5.90, 5.80, and 5.60%, respectively). The results of the sensory evaluation show that 2% ginseng Makgeolli after 3 days of aging at $4^{\circ}C$ had the highest scores for taste (5.19), flavor (5.04), and overall acceptability (5.22) among the samples.

• 한국식품영양과학회지
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• 제42권5호
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• pp.828-831
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• 2013

고춧가루 첨가 시기에 따른 사과고추장혼합물에서의 에탄올 생성과 고추장 제조 후 관능검사를 실시하여 사과고추장의 가능성을 검토하고자 하였다. 고춧가루 첨가 전의 사과고추장혼합물에서 효모의 생육은 발효 5일 후 약 6.5 log CFU/ g으로 빠른 증식을 보였으며, 에탄올 생성 농도는 발효 15일 후 3.8%에 도달하였다. 고춧가루를 미리 첨가한 사과고추장혼합물의 경우에 효모균주의 생육은 발효 20일 후 7 log CFU/g으로 증가하였고, 25일 발효 후에 에탄올 농도가 1.3 %에 이르러 고춧가루 첨가 방법에 따른 에탄올 생성 농도에서 큰 차이를 보였다. 그러나 고춧가루 첨가시기에 따른 사과고추장의 전체적인 기호성에서는 큰 차이를 보이지 않았다.

• Journal of Microbiology and Biotechnology
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• 제18권7호
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• pp.1266-1273
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• 2008

Lactic acid bacteria (LAB) with antimicrobial activity and high exopolysaccharide (EPS) production ability isolated from sourdough were studied for their fermentation characteristics as potential new starter cultures. The values of pH, titratable acidity, and viable cell counts were $4.06{\pm}0.009-4.50{\pm}0.015,\;0.787{\pm}0.020%-1.172{\pm}0.018%,\;and\;8.78{\pm}0.08-8.98{\pm}0.06$ log CFU/ml, respectively. In order to select probiotics with a high survival rate in the gut, isolates were tested to assess resistance against the artificial gastric acid and bile juice. Viable LAB counts were significantly (p<0.05) affected by the acidity. At pH 2.0, the total declines in the initial bacterial counts were 4.52$\pm$0.07 log for S. thermophilus St-Body-1, >7.98$\pm$0.03 log for E. flavescens DU-10, >7.95$\pm$0.05 log for E. faecium DU-12, and 3.15$\pm$0.06 log for L. amylovorus DU-21. Among the strains, L. amylovorus DU-21 was the only strain that had bile tolerance under simulated gastrointestinal conditions. In order to improve EPS production by L. amylovorus DU-21, the influence of carbon source was studied. When glucose was used as a carbon source, EPS production dramatically increased to 17.19$\pm$0.28 g/l (p<0.05). The maximum cell growth (10.012$\pm$>0.012 log CFU/ml) and EPS production (18.71$\pm$0.19 g/l) were achieved when 15 g/l of glucose was employed as the carbon source.