• 한국미생물·생명공학회지
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• 제51권2호
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• pp.147-156
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• 2023

Tetragenococcus halophilus CY54, an isolate from jeotgal, grows best in media with 5% NaCl and can grow at 18% and higher salt concentration. Three different doenjang samples were prepared with multiple starters including T. halophilus CY54. TBZA doenjang was prepared with T. halophilus, Bacillus subtilis, Zygosaccharomyces rouxii and Aspergillus oryzae. BZA doenjang was prepared with the same 3 starters except T. halophilus. KACC doenjang was prepared with a single starter, B. subtilis KACC16750. During 16 weeks of fermentation at 25℃, the viable counts were maintained in the range of 7-8 log CFU/g in all 3 samples. As fermentation progressed, pH decreased and titratable acidity (TA) gradually increased. Crude protein contents decreased slightly. TBZA doenjang showed higher amino-type nitrogen (ANN) and volatile basic nitrogen (VBN) contents, and KACC doenjang showed higher ammonia-type nitrogen (AMN) content. TBZA doenjang showed higher fibrinolytic and protease activity than other doenjang samples. Metabolites analyses by GC/MS showed that doenjang samples were separated from each other by partial least squares-discriminant analysis (PLS-DA) analysis. Seventeen major metabolites involved in the differences between samples were identified and they included organic acids, amino acids, sugars, fatty acids and alcohols. TBZA doenjang showed higher contents for most metabolites responsible for flavor and taste of fermented foods including doenjang. These results showed that T. halophilus could be useful as a starter for doenjang and can improve the product quality by accelerating the fermentation processes.

• 한국미생물·생명공학회지
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• 제44권3호
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• pp.254-260
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• 2016

Doenjang samples were prepared by inoculation of multiple starters consisting of two Bacillus spp., one yeast, and one fungus. Doenjang A was fermented with Bacillus amyloliquefaciens EMD17, B. amyloliquefaciens MJ1-4, Pichia farinosa SY80, and Rhizopus oryzae. Doenjang B and C were fermented with the same yeast and fungus but different Bacillus strains; namely, B. amyloliquefaciens EMD17 and B. subtilis CH3-5 for doenjang B, and B. amyloliquefaciens MJ1-4 and B. subtilis CH3-5 for doenjang C. Doenjang D was fermented with microorganisms present in rice straw (control). The doenjang samples were spiked with B. cereus ATCC14579 at two different levels, 10⁴ CFU/g doenjang (I) and 10⁷ CFU/g doenjang (II). All eight doenjang samples were fermented for 70 days at 25℃. Growth of B. cereus was inhibited in doenjang A, B, and C, with the bacterial cell count after 70 days being less than the initial 10⁴ CFU/g added, whereas B. cereus was not inhibited in doenjang D. Doenjang B showed the strongest inhibitory activity against B. cereus, with a cell count of less than 10³ CFU/g after 42 days, even when B. cereus was initially added at 10⁷ CFU/g. Some properties of the doenjang samples, such as pH, TA, and amino-type nitrogen content, were similar to those of doenjang fermented with starters only. The results indicate that carefully selected starters can effectively prevent the growth of B. cereus during doenjang fermentation.

• 한국미생물·생명공학회지
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• 제44권2호
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• pp.109-116
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• 2016

대두에 B. amyloliquefaciens 2 균주들과 P. farinosa SY80, 그리고 R. oryzae 총 4 균주를 접종한 메주를 만들었다(메주 1). 대조구로 B. subtilis KACC16450과 A. oryzae를 접종한 메주(메주 2)와 볏짚을 균원시료로 접종한 메주(메주 3)들을 제조하여 총 56일 발효시켰다. 발효 기간중 메주 1과 2의 pH와 적정산도는 메주 3보다 각각 높고 그리고 낮았다. 메주의 혈전용해능은 메주 1이 가장 높았다. 발효 기간중 모든 메주에서 B. cereus는 검출되지 않았으나 메주 2와 3에서 여러 모양과 색을 띈 잡균들이 검출되었다. 메주 2에서 histamine이 그리고 메주 3에서 tyramine이 저 농도로 검출되었으나 메주 1에서는 둘 다 검출되지 않았다. B. amyloliquefaciens EMD17이나 MJ1-4와 같은 항균력 균주들을 접종하여 메주를 제조하면 미생물학적으로 보다 안전한 장류제품들 생산이 가능할 것이다.

• 한국식품영양학회지
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• 제33권5호
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• pp.524-531
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• 2020

The purpose of this study was to evaluate the quality properties of Meju prepared by inoculating two strains of Bacillus amyloliquefaciens HJ5-2, and Aspergillus oryzae PS03. The three soybean varieties that include Daewonkong, Daechan, and Saedanbaek were used in this experiment. The fermentation temperature during the Meju aging varied at 20℃, 30℃, and 40℃, respectively. The physicochemical analysis of the soybeans, showed that the cured protein and fat contents were 34.83~43.49% and 12.91~18.90%, respectively. The pH and total acidity were 6.47~6.93 and 0.11~1.22%, respectively. The change in appearance of the Meju was that the yellow-green mold was well formed on seven days at fermentation temperature of 20℃ and 30℃, but at 40℃, there was minimal mold formation and cracking of the surface. The amino nitrogen content was highest on the Daechan Meju at 621.83 mg% for seven days. The amylase increased as the fermentation period increased in all samples, and the protease increased rapidly until the first day of the fermentation, and then gradually increased thereafter. The total number of bacteria increased or decreased as the fermentation proceeded to 6.66~10.07 log CFU/g. The mold counts increased with increasing fermentation period in the range of 6.38~8.79 log CFU/g.

• 한국식품과학회지
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• 제52권1호
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• pp.11-18
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• 2020

발효식품의 우점종 Enterococcus 속 박테리아는 식품발효에 중요한 역할을 담당할 뿐만 아니라 사람과 가축의 프로바이오틱스로 사용되는 긍정적 측면을 가지고 있지만, 균혈증, 심내막염 등의 병원감염을 일으키는 병원균으로도 알려져 있다. 또한 여러 항생제에 대한 내성균주와 부착분자, 선모, 용혈소 등의 독성인자 보유 균주들이 발견되고 있어 식품용 미생물 및 프로바이오틱스로서의 적합성에 의문이 제기되고 있다. 본 총설에서는 우선 Enterococcus의 긍적적 및 부정적 측면에 대한 정보를 제공하여 논란이 되고 있는 문제점을 제시하였고, 유전체 연구를 통하여 부정적인 측면을 보유하지 않은 식품산업에서 활용할 수 있는 균주 선발 방향을 검토하였다. 또한 우리나라 전통발효식품용 종균개발 현황과 신규 식품용 미생물 인허가 제도를 검토하여 문제점을 파악하였다. 결론으로 Enterococcus 연구결과에 근거 우리나라 신규 식품용 미생물의 안전성 평가 방향성을 제시하였다.