• Journal of the Korean Society of Food Culture
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• v.7 no.4
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• pp.323-328
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• 1992

Three kinds of soy sauce were prepared using the brick type of conventional meju (A), the brick type of meju of Aspergillus oryzae (B), and the grain type of meju of Aspergillus oryzae (C) in summer. Free amino acids were analyzed in according to aging time of those products. Findings are as follows. Lysine, histidine, serine, glycine, valine, methionine, and phenylalanine were detected in all kinds of soy sauce at the beginning preparation. Aspertic acid, glutamic acid, alanine, threonine, arginine, and leucine were detected during 90 days. Isoleucine and tyrosine were detected during 180 days. Lysine and histidine were shown higher content among the detected free amino acids. The each content of glutamic acid, aspartic acid, and methionine was decreased in passing the aging time. The total content of free amino acids was shown 3,559-4,119 mg/100 ml at the 180 days. The total content of free amino acids of soy sauce C was higher than that of other soy sauces.

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1523-1531
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• 2012

The metabolite profile of meju during fermentation was analyzed using mass spectrometry techniques, including GC-MS and LC-MS, and the bacterial diversity was characterized. The relative proportions of bacterial strains indicated that lactic acid bacteria, such as Enterococcus faecium and Leuconostoc lactis, were the dominant species. In partial least-squares discriminate analysis (PLS-DA), the componential changes, which depended on fermentation, proceeded gradually in both the GC-MS and LC-MS data sets. During fermentation, lactic acid, amino acids, monosaccharides, sugar alcohols, and isoflavonoid aglycones (daidzein and genistein) increased, whereas citric acid, glucosides, and disaccharides decreased. MS-based metabolite profiling and bacterial diversity characterization of meju demonstrated the changes in metabolites according to the fermentation period and provided a better understanding of the correlation between metabolites and bacterial diversity.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.11a
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• pp.101-103
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• 2005

This study was performed to investigate the changes of Bacillus sp. of traditional Korean soy sauce (kan-jang) and soybean paste (doen-jang) during the ripening and storage for 12 months. All of the preparation methods for soy sauce and soybean paste followed the recommendations of the Korea Food Research Institute. The soy sauce and soybean paste were analyzed at 0, 6, and 12 months. The numbers of Bacillus sp. of meju (soybean cakes) or soy sauce and soybean paste at the initial stage were significantly higher than those of soybeans (p<0.05). The number of Bacillus sp. increased in soy sauce and soybean paste after 12 months of ripening and storage. This study indicates that this comes from the preparation and fermentation of meju. It is suspected that the organoleptic characteristics of soy sauce and soybean paste might be inferior over 1 year of storage time. Therefore, more research fur overall microbiological quality changes of soy sauce and soybean paste during the storage period should be conducted to interpretate this characteristics more accurately.

• Journal of the Korean Society of Food Culture
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• v.35 no.1
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• pp.1-13
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• 2020

This study categorized and made considerations of the fermented soybean pastes into Meju, Chungjang, Si, mixed Jang, and other Jang in accordance with the manufacturing methods described in the fermented soybean paste section of Sangayorok (1450's), Suunjapbang (1540's) and Gyemiseo (1554). These are ancient cook books written in Chinese characters during the first half of the Joseon Dynasty. The content on the fermented soybean pastes recorded in these books included 24 items in Sangayorok, 11 items in Suunjapbang, and 14 items in Gyemiseo. In conclusion, the most important fermented soybean pastes during the first half of the Joseon Dynasty were those used to produce soy sauce-like seasoning for the purpose of a-chieving a salty taste with Meju made of soybeans as the main ingredient. The manufacturing techniques for such traditional fermented soybean pastes have been passed down through history to the present era.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.446-451
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• 1999

The protease produced by Mucor racemosus f. racemosus PDA 103 from meju was purified by precipitating with 80% saturated ammonium sulfate, CM Sephadex C-50 ion-exchange chromatography, and secondary Sephadex G-100 gel filtration chromatography. The specific activity of the purified enzyme was 60.1unit/mg protein and the purification fold of the enzyme was 83.5. The molecular weight of the enzyme was estimated 33,746Da and the enzyme was elucidated as monomer by LC-MS and SDS-PAGE. The number of amino acids was evaluated about 330 residues.

• Food Science of Animal Resources
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• v.39 no.3
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• pp.355-370
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• 2019

The present study aimed at evaluating effects of traditional sauce type and storage time on shelf-life and flavor compounds of marinated pork cooked by Sous-Vide method. Five different traditional sauces (Meju soy sauce, Brewed soy sauce, Fish-soy sauce, Ishiru fish sauce and Anchovy fish sauce) purchased from Asian countries were used. After marination with the sauces, polyvinylchloride film bags containing the marinated pork samples were cooked using Sous-Vide method for $55^{\circ}C$ for 5 h and $60^{\circ}C$ for 30 min, and were then stored for 8 wk at $10^{\circ}C$. Results showed that the pork samples marinated with the sauces retarded the growth of total plate counts (TPC) during storage. At $8^{th}$ wk storage, TPC counts were significantly lower in all samples marinated with the sauces compared to control (p<0.05). Lipid oxidation level was significantly lower in the T2 (Meju soy sauce) and T6 (Anchovy fish sauce) compared to those of T3 (Brewed soy sauce) and T5 (Ishiru fish sauce) or control after 8 wk storage (p>0.05). Forty volatile flavor compounds were detected from the control and marinated samples at $4^{th}$ wk of storage. The pork marinated with Anchovy fish sauce presented significantly higher amounts of importantly pleasant flavor compounds such as; pyrazines and sulfurcontaining compounds than those marinated with other remaining sauces and control. It is concluded that the marination with Anchovy fish sauce partly improved the shelf-life and increased amounts of pleasant flavor compounds of Sous-Vide cooked pork products during storage in comparison to the other remaining sauces.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.478-486
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• 1998

The isolates of Rhizopus collected from Korean traditional fermented food meju and nuruk, were compared with the well known species of Rhizopus donated. The isolates of Rhizopus were identified with the numerical analyses calculated from RAPD-DNA bands, and confirmed with the microscopic observations of morphological features on PDA. The isolates of R. oryzae purchased were segregated through the results of RAPD or the morphological features. The species of R. nigricans, known as an illegitimate species, were different from those of R. stolonife and it is estimated that they are species of Rhizopus, again. According to microscopic observations and the result of RAPD, Some isolates of R. oryzae purchased belong to R. nigricans and are completely different from R. oryzae in their growth. The isolates of R. nigricans included with several isolates of R. oryzae identified for the different phenotypes and were heterogenous. The isolate of R. oligosporus were speculated to be different from morphological features of Rhizopus, but to be similar to the species of Absidia on the apophysis of sporangium. Its sporangiophore or mycelium was observed to be dark black, but the sporangia were not in those of R. oligosporus. The isolates collected from Korean traditional nuruk showed genetic diversity, and also considered to be different tastes in Korean rice wines.

• Korean journal of food and cookery science
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• v.24 no.2
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• pp.243-250
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• 2008

This study examined the quality characteristics of soybean pastes that were prepared using different ratios of whole soybean meju inoculated with three different types of microbial strains. The five samples were prepared with meju inoculated with Aspergillus oryzae KFRI 995, Bacillus subtilis F4005, mixture with A. oryzae KFRI 995 and B. subtilis F2315, mixture with A. oryzae KFRI 995 and B. subtilis F4005, and mixture using all three strains, respectively. Over two months of fermentation, pH gradually decreased, whereas total acidity increased. And across samples and fermentation periods, there were no considerable changes in moisture or crude protein. In all five samples, amino-type nitrogen levels increased approximately 2- to 3-fold as compared to initial levels; the sample inoculated with A. oryzae KFRI 995 showed the highest level (205.2 mg%) of amino-type nitrogen. Throughout fermentation, the five samples displayed differences in their reducing sugar levels according to the inoculated microorganisms. The lowest level of lightness and highest level of redness occurred in the sample inoculated with B. subtilis F2315 showed a lowest level in lightness and a highest level of redness, indicating a strong browning reaction. Finally, the samples inoculated with A. oryzae KFRI 995 and B. subtilis F4005, respectively, showed had similarly high preference scores as compared to the other samples.

• The Korean Journal of Mycology
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• v.25 no.1 s.80
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• pp.35-45
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• 1997

The yellow fungal isolates inhabiting at the cereals (Hwang-Kuk, HK-fungi) were widely collected from the mejus and nuluks in Korea; the meju is a raw material for Korean traditional foods for soysauce and soypaste, and the nuluk is a raw material for Korean traditional rice wine. These isolates, well known as an Aspergillus oryzae producing amylase for Korean rice wine or producing protease for soybeans, were compared with Aspergillus species known. All isolates were microscopically observed to be a species of A. oryzae or its related, but to be difficult to be identified. Thus, RAPD-DNA techniques were applied for these isolates and analyzed with nummerical values using NT-system, or Ecological programs or Factorial analyses. Several common bands of RAPD-DNA in the 28 isolates were synthesized with the different OPD primers and speculated to be used for identification of HK fungi. The HK-fungi isolated were revealed to belong to the group of A. flavus previously defined. Particularly, the isolates collected from mejus were analyzed to be more closed to A. flavus, The species of A. flavus, A. oryzae and A. sojae were grouped at the values lower than those indicating the diversity of species. In other words, these three fungal species were not distinguishable and all isolates known as a HK-fungus were very closed to A. flavus, All isolates were not diversified at groupings of RAPD-DNA, and considered to be not the natural flora at the mejus or nuluks. The meju or nuluk having the above fungi as the fungal flora were speculated to be not termed "Korean traditional foodstuffs".The yellow fungal isolates inhabiting at the cereals (Hwang-Kuk, HK-fungi) were widely collected from the mejus and nuluks in Korea; the meju is a raw material for Korean traditional foods for soysauce and soypaste, and the nuluk is a raw material for Korean traditional rice wine. These isolates, well known as an Aspergillus oryzae producing amylase for Korean rice wine or producing protease for soybeans, were compared with Aspergillus species known. All isolates were microscopically observed to be a species of A. oryzae or its related, but to be difficult to be identified. Thus, RAPD-DNA techniques were applied for these isolates and analyzed with nummerical values using NT-system, or Ecological programs or Factorial analyses. Several common bands of RAPD-DNA in the 28 isolates were synthesized with the different OPD primers and speculated to be used for identification of HK fungi. The HK-fungi isolated were revealed to belong to the group of A. flavus previously defined. Particularly, the isolates collected from mejus were analyzed to be more closed to A. flavus, The species of A. flavus, A. oryzae and A. sojae were grouped at the values lower than those indicating the diversity of species. In other words, these three fungal species were not distinguishable and all isolates known as a HK-fungus were very closed to A. flavus. All isolates were not diversified at groupings of RAPD-DNA, and considered to be not the natural flora at the mejus or nuluks. The meju or nuluk having the above fungi as the fungal flora were speculated to be not termed 'Korean traditional foodstuffs'.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.365-368
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• 1997

This study was carried out to investigate the optimum mashing and maturing conditions for Korean traditional Kanjang(soy sauce) production and to reduce the fermentation period. The effects of maturing time of soy sauce mash, maturing temperature, salt concentration and the ratio of Meju to salt brine on the quality of Kaniang(total nitrogen, pH and color) were examined. Soy sauce pigments and about 90% of N constituents contained in soybean Meju(Koji) in soy sauce mash were degraded and solubilized into liquid portion (soy sauce) of the mash within five days of maturing at $30^{\circ}C$ with the mashing ratio(weight/volume) of 1 : 4 of soybean(as raw soybean) to 20% salt brine. No remarkable effects of soy sauce maturing temperature in the range of $5^{\circ}C{\sim}30^{\circ}$ on the digestion and solubilization of N components and pigment extraction during five days of soy sauce mash maturing were observed. Optimum mashing salt brine concentration for the digestion and solubilization of N components and pigment extraction during soy sauce maturing at $30^{\circ}C$ were observed to be in the range of $15{\sim}20%$. The suitable mashing ratio of Meju to salt brine (wt./vol.) to match N content of the standards of identity of Korean traditional Kanjang(soy sauce) was found to be below 1 : 5.