• Journal of Microbiology and Biotechnology
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• 제24권5호
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• pp.648-660
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• 2014

Doenjang, a traditional Korean fermented soybean paste, is made by mixing and ripening meju with high salt brine (approximately 18%). Meju is a naturally fermented soybean block prepared by soaking, steaming, and molding soybean. To understand living bacterial community migration and the roles of bacteria in the manufacturing process of doenjang, the diversity of culturable bacteria in meju and doenjang was examined using media supplemented with NaCl, and some physiological activities of predominant isolates were determined. Bacilli were the major bacteria involved throughout the entire manufacturing process from meju to doenjang; some of these bacteria might be present as spores during the doenjang ripening process. Bacillus siamensis was the most populous species of the genus, and Bacillus licheniformis exhibited sufficient salt tolerance to maintain its growth during doenjang ripening. Enterococcus faecalis and Enterococcus faecium, the major lactic acid bacteria (LAB) identified in this study, did not continue to grow under high NaCl conditions in doenjang. Enterococci and certain species of coagulase-negative staphylococci (CNS) were the predominant acid-producing bacteria in meju fermentation, whereas Tetragenococcus halophilus and CNS were the major acid-producing bacteria in doenjang fermentation. We conclude that bacilli, LAB, and CNS may be the major bacterial groups involved in meju fermentation and that these bacterial communities undergo a shift toward salt-tolerant bacilli, CNS, and T. halophilus during the doenjang fermentation process.

• Journal of Microbiology and Biotechnology
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• 제30권11호
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• pp.1697-1705
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• 2020

Meju, a type of fermented soybean paste, is used as a starter in the preparation of various Korean traditional soybean-based foods. In this study, we performed Illumina-MiSeq paired-end sequencing for microbial communities and mass spectrometry analysis for metabolite profiling to investigate the differences between 11 traditional meju products from different regions across Korea. Even though the bacterial and fungal communities showed remarkable variety, major genera including Bacillus, Enterococcus, Variovorax, Pediococcus, Weissella, and Aspergillus were detected in every sample of meju. The metabolite profile patterns of the 11 samples were clustered into two main groups: group I (M1-5) and group II (M6-11). The metabolite analysis indicated a relatively higher amino acid content in group I, while group II exhibited higher isoflavone, soyasaponin, and lysophospholipid contents. The bioactivity analysis proved that the ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) radical-scavenging activity was higher in group II and the FRAP (ferric reducing antioxidant power) activity was higher in group I. The correlation analysis revealed that the ABTS activity was isoflavonoid, lipid, and soyasaponin related, whereas the FRAP activity was amino acid and flavonoid related. These results suggest that the antioxidant activities of meju are critically influenced by the microbiome and metabolite dynamics.

• 한국조리학회지
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• 제6권3호
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• pp.357-371
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• 2000

Changes of Microflora, enzyme activity, and contents of several taste compounds in traditional Kanjang(Korean Soy Sauce) with the variation of fermentation jars and Meju(fermented soybean brick)concentration were studied. Substitution possibilities of clay jar with glass jar and improvement possibilities of taste and nutritional value with increased Meju concentration were examined. (1) Aerobic bacteria and lactic acid bacteria were enumerated during fermentation and ripening period. But yeast and molds were hardly isolated. The number of viable cells showed small changes during fermentation and ripening period. (2) Isolated Aerobic bacteria were identified as Bacillus subtilis, Bacillus lichenformis, and lactic acid bacteria were identified as Lactlbacillus lactis lactis and lactobacillus brevis. (3) The activities of $\alpha$-amylase and $\beta$-amylase increased during fermentation period, but did not show any trend by fermentation jars or Meju concentrations. Protense activity showed small difference among four samples, and increased during the fermentation period.

• 한국미생물·생명공학회지
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• 제27권6호
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• pp.466-470
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• 1999

Protease production and its characteristics were investigated with Mucor racemosus f. racemosus PDA 103 which was isolated from Korean traditional meju. Optimum culture conditions of the strain for the production of the protease in basic medium[bean(Baektae):H2O=1:1(w/v)] were as follows: pH 6, 3$0^{\circ}C$ and 72hrs. Optimum pH and temperature for the enzyme activity of the protease produced by Mucor racemosus f. racemosus were pH 5 and 5$0^{\circ}C$, respectively. The enzyme was relatively stable a pH2.0~5.0 and at temperature below 4$0^{\circ}C$. Phenylmethane-sulfonyl fluoride and Ag+ inhibited the enzyme activity. This indicates that the enzyme is serine protease. Km value was 0.9$\times$10-4M and Vmax value was 5.93$\mu\textrm{g}$/min. This enzyme hydrolyzed casein more rapidly than bovine albumin.

• 한국지역사회생활과학회지
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• 제12권1호
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• pp.41-49
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• 2001

The purpose of this study was to investigate the preparation patterns of traditional fermented soybean products(jang) from the housewives living in Yangsan. 89.4% of the respondents used once a day, every meal and the frequency of eating was higher with getting older. 70% answered that the taste of their homemade doenjang was good, while only 2.5% were not be satisfied with their doenjang. According to the survey, 82.2% of the housewives used the meju made by the traditional method for jang preparation, of which perparation patterns showed remarkablely in the housewives living in the independent home. On the other hand, we could see that the amount of jang preparated one time in each home of Yangsan region was approximately 6∼10kg or 16∼20kg. The hard tasks of jang preparation were seasoning, storing and meju preparation. Especially, housewives living in the communal house had a difficulty in storing of jang. But most wants to continue to prepare jang by traditional method at home.

• Journal of Microbiology and Biotechnology
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• 제21권11호
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• pp.1166-1173
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• 2011

Meju is a traditional Korean fermented soy product used as a key element for soy sauce and doenjang. Bacilli with antimicrobial activity were isolated from meju prepared by traditional methods at Sunchang county, Jeollabukdo, Korea. Six isolates were identified as Bacillus amyloliquefaciens by recA gene sequencing and RAPD-PCR. One isolate, B. amyloliquefaciens MJ5-41, showed the strongest fibrinolytic activity. A 27 kDa active fibrinolytic enzyme, AprE5-41, was purified from the culture supernatant of MJ5-41 grown on LB by chromatographic methods. The optimum pH and temperature for purified AprE5-41 were 7.0 and $45^{\circ}C$, respectively. AprE5-41 quickly degraded $A{\alpha}$ and $B{\beta}$ chains but not the ${\gamma}$-chain of fibrinogen. AprE5-41 exhibited the highest specificity for N-succinyl-Ala-Ala-Pro-Phe p-nitroanilide, a known substrate for ${\alpha}$-chymotrypsin, cathepsin G, and subtilisin BPN'. The structural gene, aprE5-41, was cloned by PCR and successfully expressed in B. subtilis.

• 한국식품영양학회지
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• 제31권5호
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• pp.712-719
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• 2018

This study was carried out to obtain basic data on Korean traditional Meju collected from 18 regions (TM1~TM18) in Korea and to define and control quality. The shape of Meju was mostly rectangular and the weight was 0.84~2.04 kg. The physicochemical analysis showed: pH, 5.31~8.21; total acidity, 0.91~2.74%; moisture content, 4.79~42.16%; and soluble protein content, 41.37~23.48%. Hunter color values for L (lightness), a (redness), and b (yellowness) ranged from 39.07~67.92, 3.57~8.87, and 7.48~20.67, respectively. The amino nitrogen contents of all samples were in the range of 257.29 to 839.58 mg% and TM13 showed the highest content (839.58 mg%). Total viable cells, yeast and mold counts of Meju were 8.43~5.91 log CFU/g, 2.48~5.19 log CFU/g, and 3.42~7.48 log CFU/g, respectively. Based on the results, it is proposed that quality standards and management of Meju fermentation conditions and information about different varieties of soybeans used should be made available.

• Mycobiology
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• 제41권2호
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• pp.100-107
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• 2013

Diverse fungi are present in Korean traditional meju and they are known to play an important role in fermented soybean products. To determine the origin of the fungi in meju, we examined the mycoflora of soybeans from 10 traditional meju factories. The samples were untreated or treated with sodium hypochlorite, and placed on malt extract agar (MEA), dichloran 18% glycerol agar (DG18), and dichloran rose bengal chloramphenicol agar (DRBC) medium. A total of 794 fungal strains were isolated and they were identified as 41 genera and 86 species. From sodium hypochlorite untreated soybeans, the genera, Cladosporium (55%), Eurotium (51%), Fusarium (33%), Penicillium (22%), and Aspergillus (exclusion of Eurotium) (20%), were mainly isolated, and Eurotium herbariorum (22%), Eurotium repens (18%), Cladosporium tenuissimum (18%), F. fujikuroi (18%), Aspergillus oryzae/flavus (7%), and Penicillium steckii (6%) were the predominant species. In case of sodium hypochloritetreated soybeans, Eurotium (31%) and Cladosporium (5%) were frequently isolated, but Aspergillus (excluding Eurotium), Penicillium and Fusarium which were frequently isolated from untreated soybeans, were rarely isolated. Eurotium herbariorum (21%), Eurotium repens (8%), and Cladosporium tenuissimum (3%) were the predominant species. Of the 41 genera and 86 species isolated from soybeans, 13 genera and 33 species were also found in meju. These results suggest that the fungi on soybeans may influence the mycoflora of meju.

• 한국식품과학회지
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• 제34권3호
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• pp.400-406
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• 2002

된장제품의 경우 갈변의 해결은 소비자의 불만을 해소시킬 수 있는 중요한 개선책으로 본 연구에서는 소비자의 기호도에 맞는 색상의 재래식 된장을 개발하였다. 우리나라 장류 제조사에서 제조된 시판 재래식 된장의 이화학 성분 및 색도를 조사 분석하고 이를 위해 대두를 수침, 증숙, 냉각 및 쵸핑한 것에 분쇄시킨 재래식 메주를 다양한 비율로 배합하여 시료 된장을 제조한 후 $30^{\circ}C$에서 27일 동안 저장 보관하면서 발효기간에 따른 아미노태질소, pH, 색상을 분석하고 현재 시판 중인 재래식 된장제품과 비교 하였으며, 관능검사도 실시하였다. 재래식 메주와 증숙대두의 배합비를 달리하여 제조한 된장 처리구를 비교시, 재래식 메주만으로 처리시킨 처리구에서 아미노태질소함량이 가장 높았고 증숙대두의 함량이 증가할수록 아미노태질소함량이 줄었다. 발효기간에 따른 pH변화는 모든 처리구에서 초기 알칼리성으로부터 약산성쪽으로 변화되었다. 재래식된장의 색상이 가장 많이 개선된 것은 재래식 메주와 증숙대두의 비가 1.0 : 4.0인 처리구였으며, 이를 시판 된장과 관능적 비교를 한 결과 색, 향 및 맛에서 우수한 것으로 평가되어 기존제품과 비교하여서도 시장성이 있다고 판단되었다.

• 한국균학회지
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• 제24권4호통권79호
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• pp.329-336
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• 1996

From five years' previous work, the fungal isolates of Scopulariopsis were reported to be important flora at the late stage of meju fermentation. Mainly, the white or pale brown powders of spore mass of these fungi were observed on the surfaces of rectangular mejus, and to be an important sign for well-done Korean traditional home - made mejus. Out of the five isolates previously collected and stored, two kinds of Scopulariopsis isolates were identified as S. brevicauli and S. fusca. The microscopic differences between two were found to be branching patterns of annellophore and ornamentations of spore wall (warty and smooth). However, the intermediate form between two ornamentations of spore wall were also observed in our isolates. This observation was consistent with other result made from the protein electrophoresis. The isolates of Scopulariopsis were considered to be similar or superior to those of Aspergillus species, as compared with production of protease and amylase related enzymes. Thus, these isolates were speculated to be important fungi in Korean traditional home - made meju fermentation and also in production of protease and amylase.