• Journal of Microbiology and Biotechnology
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• v.24 no.5
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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 the Korean Society of Food Science and Nutrition
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• v.15 no.4
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• pp.1-9
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• 1986

The mashes of soybean paste were preparea using the conventional meju fermented naturally by wild microoganisms or the new types of meju fermented by pure cultures of Aspergillus oryzae, Bacillus natto and B. subtilis to elucidate changes during the aging period. The results obtained are as follows ; The soybean paste made with conventional meiu and Asp. oryzae meju showed higher content of amino nitrogen than those of B, natto and B. subtilis meju. Soybean paste made with conventional meju contained a little more content of total and reducing sugars than other soybean pastes. ph during aging period was higher than 5.0 for the Asp. oryzae paste while less than 4.5 for B. subtilis paste. Aspartic acid. threonine, serine, glutamic acid, glycine, alanine, cystine, valine, methionne, leucine and histidine for Asp. oryzae paste ; tyrosine, arginine and proline for conventional meju paste; and isoleucine and phenylalanine for B. subtilis paste were found to be peak amount 90 days after the preparation. The content of total free amino acid was high in the order of Asp. oryzae paste, conventional paste, B. natto paste and B. subtilis paste.

• Food Science and Biotechnology
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• v.16 no.3
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• pp.386-391
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• 2007

This study was conducted to observe quality characteristics of whole soybean meju fermented with germinated soybean (Glycine max: Hwanggeumkong). The germination rate after 24 hr was $23.0{\pm}1.2%$, then increased rapidly to $90.2{\pm}1.3%$ at 36 hr of germination, and finally reached a level of $99.4{\pm}0.3%$ at 60 hr of germination. It was confirmed that the total isoflavone content immediately after soaking was 100.1 mg%, increasing during the beginning of the germination process; it continued to increase to 114.0 mg% by 24 hr of germination, but decreased thereafter. The isoflavone content at 60 hr of germination was 101.6 mg%. A total of 6 organic acids were detected, and total organic acid content ranged from 963.1-1,145.3 mg%. Differences based on the degree of germination in the raw material were insignificant. The free amino acid levels of the whole soybean meju made from non-germinated soybeans and from soybeans that had germinated 48 hr were 2,580.9 and 2,519.7 mg%, respectively. The content of glutamic acid was highest followed by aspartic acid, lysine, leucine, and proline.

• Applied Biological Chemistry
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• v.35 no.4
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• pp.286-293
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• 1992

This study was investigated on the change of physico-chemical properties at various mixture ratio of improved Meju and Natto during the aging of soybean paste. pH was increased on the improved Meju with increasing the mixture ratio of Natto, but pH was decreased in Korean traditional Meju. Change of nitrogen compound was 3 times higher and aging was faster in increased ratio of Korean traditional Meju than that of improved Meju. Brown color was not changed as compared to the initial stage, however the value of brown color was higher in the Korean traditional Meju than that of other group. In sensory evaluation, the mixture ratio of improved Meju, Korean traditional Meju and Natto (48 : 48 : 5) was the best acceptables.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.195-200
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• 2003

Methods of adding barley malt as source of carbohydrates and enzymes in the production of kanjang in order to improve it's tastes and qualities were investigated. Soybean meju, soybean-malt meju and soybean meju cummalt was mashed with 20% salt brine in the ratio of 1:3 respectively, matured and analyzed the chemical compositions of the soy sauce mash samples for 150 days of maturing. Organoleptic evaluations for the matured soy sauce samples were done. The higher total nitrogen, TCA soluble nitrogen, O.D. at 500 nm, pure extract and lactic acid content could be observed with the soy sauce mash made of soybean-malt meju than those of contrast one from the beginning of the mashing throughout to the whole maturing period of 150 days. The higher the content of malt in the soybean-malt meju, the higher those content in the mash. But the lower content of those compositions in the soy sauce mash made of soybean meju cum malt than those in the contrast was found. The highest scores in all the sensory characteristics including 7.56 points, which were significantly different from that of contrast soy sauce at 5% level, in overall palatability were obtained by the soy sauce made of soybean-malt meju added with 30% malt in the organoleptic evaluations.

• Mycobiology
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• v.43 no.3
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• pp.218-224
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• 2015

Aspergillus is an important fungal genus used for the fermentation of Asian foods; this genus is referred to as koji mold in Japan and China. A. oryzae, A. sojae, and A. tamari are used in the production of miso and shoyu in Japan, but a comprehensive taxonomic study of Aspergillus isolated from Meju, a fermented soybean starting material for traditional soy sauce and soybean paste in Korea, has not been conducted. In this study, various Aspergillus species were isolated during a study of the mycobiota of Meju, and the aspergilli were identified based on phenotypic characteristics and sequencing of the ${\beta}$-tubulin gene. Most strains of Aspergillus were found to belong to the following sections: Aspergillus (n = 220), Flavi (n = 213), and Nigri (n = 54). The most commonly identified species were A. oryzae (n = 183), A. pseudoglaucus (Eurotium repens) (n = 81), A. chevalieri (E. chevalieri) (n = 62), A. montevidensis (E. amstelodami) (n = 34), A. niger (n = 21), A. tamari (n = 15), A. ruber (E. rubrum) (n = 15), A. proliferans (n = 14), and A. luchuensis (n = 14); 25 species were identified from 533 Aspergillus strains. Aspergillus strains were mainly found during the high temperature fermentation period in the later steps of Meju fermentation.

• Applied Biological Chemistry
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• v.49 no.1
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• pp.7-14
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• 2006

This study was carried out to examine the quality characteristics of soybean pastes made of Meju with mold-producing pretense isolated from traditional Meju. The changes in moisture content, enzyme activity (amylase, protease, lipase), reducing sugar, amino-type nitrogen contents and anti-oxidant activity were investigated during the aging period. The moisture contents decreased gradually with time. Amylase activity decreased during the aging period while pretense and lipase activities increased until 30-45 days of aging, but decreased thereafter, Especially pretense activity in soybean paste with mold was greater than that in the control. Amino-type nitrogen and ammoniacal nitrogen contents increased, but reducing sugar contents decreased with time. Amino-type nitrogen contents were greater in soybean paste made of Meju with isolated mold than those in the control. Antioxidative activity was also confirmed in soybean paste.

• Microbiology and Biotechnology Letters
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• v.11 no.3
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• pp.241-248
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• 1983

Lupin seed was used to make Meju, the fermentation starter for Korean soybean sauce and paste in substitution for soybean and the fermentation characteristics were compared with those of soybean. Mejus were prepared by in-oculating Asp. oryzae on the cooked whole beans. The dried Mejus were used for making fermented bean sauce and paste by mixing with brine and subsequent ripening for 4 weeks. In general the protease activity and amylase activity-during ripening were higher in lupin seed Meju than those of soybean Meju. The increase in protease activity correlated to the increase in $\alpha$-amino nitrogen content of the fermented paste and sauce. The development of dark-brown color of the sauce during ripening faster with lupin seed Meju compared to soybean Meju. In sensory evaluation the flavor score of lupin seed sauce and paste was slightly lower than that of soybean products but the overall quality of fermented lupin seed sauce was acceptable.

• Journal of Microbiology and Biotechnology
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• v.6 no.4
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• pp.278-285
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• 1996

We identified volatile components of traditional Korean soy sauce and soybean paste which had been manufactured with the same traditional Meju with a view to improving the quality of traditional Korean soy sauce and soybean paste. All of the volatile components were extracted by simultaneous steam distillation-extraction (SDE) apparatus. To obtain more detailed information, whole volatile components were separated into fractions. The volatile components of the whole and of each fraction were identified by GC-mass and Kovat's retention index. Sixty two and eighty six components were identified in traditional Korean soy sauce and soybean paste, respectively. Many aroma components of traditional Korean soy sauce differ from those of traditional Korean soybean paste. It was confirmed that many aroma components of traditional Korean soy sauce and soybean paste are completely different from those of Japanese fermented soy sauce (Shoyu) and soybean paste (Miso).

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.6
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• pp.917-924
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• 1995

Four types of soybean paste(Doenjang), prepared with traditional Korean meju, natto meju, koji and mixture of koji and natto meju, were analyzed for compositions of free sugars and fatty acids. Crude protein content of the soybean pastes were ranged from 10.3~14.6% and in the order of traditional Korean soybena paste>natto soybena paste>koji & natto soybean paste>koji soybean paste during fermentation of Doenjang. Ethyl alcohol contnet was relatively higher in koji and natto soybean paste after fermentation for 75 days, and its content was the highest in koji soybean paste as 2.8% after fermenting for 90 days. Contents of total sugars and reducing sugars decreased during fermentation of doenjang in the order of koji soybena paste>koji and natto soybean paste>traditional soybean paste>natto soybean paste. Among the free sugars glucose, galactose, mannose and arabinose were identified in soybean paste, and glucose and galactose were more bundant. Contents of glucose and total free sugars were the highest in the traditional Korean soybean paste and galactose content was highest in koji soybean paste. In fatty acid compositions of soybean pastes, palmitic, stearic, oleic, linoleic, linolenic and arachidonic acids were analyzed, and the most abundant fatty acid was found to be oleic acid as 38.5~46.9% in all samples tested. But no significant differences in ratio of fatty acid compositions was observed from tested samples during the fermentation period.