• Journal of Applied Biological Chemistry
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• 제52권4호
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• pp.205-211
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• 2009

한국 재래식 간장의 대량생산을 위한 기반 연구를 확립하기 위하여 크기별로 제조된 메주의 특성을 비교하고, 재래식 메주의 제조 방법을 개선시킨 메주(IM-meju, Improved Method for kanjang production, $25{\sim}30^{\circ}C$의 온도와 80~90%의 상대습도로 발효)와 전통식 메주(CM-meju, Conventional Method, $15{\sim}20^{\circ}C$의 온도와 40~50% 상대습도에서 발효)를 제조하여 특성을 비교하였다. 전통식 메주의 크기를 다양하게 제조하여 특성을 비교해 본 결과 메주의 크기에 따른 총질소와 가용성 질소의 함량은 큰 차이를 보이지 않았으나, 유리아미노산의 함량은 크기가 작아질수록 감소하였다. 비휘발성 유기산과 유리당 함량은 $23{\times}11{\times}7\;cm$ 크기에서 각각 1360.5 mg%와 3,770.2 mg%로 가장 높은 결과를 보여줌으로서 최적의 크기인 것으로 판단되었다. 크기별로 제조된 메주를 제조방법 즉, 발효조건에 따라 제조한 간장의 특성을 비교해본 결과 총질소 함량은 크기에 따라 큰 차이를 보이지 않았으나 유리당의 함량은 크기가 작아짐에 따라 증가하였으며, $23{\times}11{\times}7\;cm$ 크기의 메주로 제조한 간장에서 545.6 mg%의 높은 함량을 나타내었다. 비휘발성 유기산함량에서도 크기가 작아질수록 감소하였으며, 이 중 $23{\times}11{\times}7\;cm$ 크기의 메주로 제조한 간장에서 303.3 mg%의 가장 높은 함량을 보였다. 또한 젖산의 함량도 크기가 작아짐에 따라 감소하였으나, 염도는 높아졌다. 그리고, CM-meju와 IM-meju의 특성을 비교해 본 결과 제조 후 총질소 함량은 CM-meju에서 높았으나, 수가용성 질소, 20% 염수 가용성 질소는 CM-meju보다 IM-meju 에서 높은 결과를 나타내었으며, 유리 아미노산 함량은 CM-meju와 IM-meju 에서 2499.6, 2748.9 mg%의 함량으로서 CM-meju보다 IM-meju에서 높았다. 제조법을 개선시킨 IM-meju는 CM-meju보다 간장의 품질에 영향을 주는 성분들, 즉 총질소 함량, 유리당 그리고 유리 아미노산 등의 함량이 높을 뿐만 아니라 질적인 면에서도 우수하다고 사료된다.

• 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.

• Journal of Microbiology and Biotechnology
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• 제34권4호
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• pp.863-870
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• 2024

Meju, a fermented soybean brick, is a key component in soybean foods like doenjang and ganjang, harboring a variety of microorganisms, including bacteria and fungi. These microorganisms significantly contribute to the nutritional and sensory characteristics of doenjang and ganjang. Amplicon-based next-generation sequencing was applied to investigate how the microbial communities of meju fermented at low and high temperatures differ and how this variation affects the microbial communities of doenjang, a subsequently fermented soybean food. Our metagenomic data showed distinct patterns depending on the fermentation temperature. The microbial abundance in the bacterial community was increased under both temperatures during the fermentation of meju and doenjang. Weissella was the most abundant genus before the fermentation of meju, however, it was replaced by Bacillus at high temperature-fermented meju and lactic acid bacteria such as Weissella and Latilactobacillus at low temperature-fermented meju. Leuconostoc, Logiolactobacillus, and Tetragenococcus gradually took over the dominant role during the fermentation process of doenjang, replacing the previous dominant microorganisms. Mucor was dominant in the fungal community before and after meju fermentation, whereas Debaryomyces was dominant under both temperatures during doenjang fermentation. The dominant fungal genus of doenjang was not affected regardless of the fermentation temperature of meju. Strong correlations were shown for specific bacteria and fungi linked to specific fermentation temperatures. This study helps our understanding of meju fermentation process at different fermentation temperatures and highlights different bacteria and fungi associated with specific fermentation periods which may influence the nutritional and organoleptic properties of the final fermented soybean foods doenjang.