• Applied Biological Chemistry
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• v.13 no.1
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• pp.35-42
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• 1970

Five samples of Korean native Maeju(fermented soy-bean mash) loaves which were collected each from Kyunggi, Chungchung, Kangwon, Cholla and Kyungsang-Do were examined for their fermenting microorganisms. The results of taxonomic and ecological studies of fermentation microorganisms in these Maeju loaves were as the fellows. (1) The fungus flora grew only is the outer layer of Maeju loaves. Miscellaneous molds, 3 species of Mucor, 2 species of Pericallium., one species each of Scopulariopsis and Aspergillus, were isolated. None of them seemed exclusively predominant to be able to designate as the ecologically significant. (2) The bacterial flora which consisted of two species, Bacillus subtilis and Bacillus pumilus were distributed uniformly in th a entire Maeju loaves. The inner parts of Maeju loaves were especially inhabited solely by these bacterial flora. Probably the Korean native Maeju fermentation could be characterized by these bacterial flora. A Staphylococcus species was also isolated probably as a casual contaminant. (3) The yeasts, Rhodotorula flava and Torulopsis dattila, were isolated from Maeju loaves though their ecological significance was not clear. (4) The ecological aspects of fermentation microbes in the outer and inner parts of Maeju loaves were apparently different, consequently different fermentation processes might have occurred in these two parts and it brought quite different final outlooks in the final matured Maeju loaves. The outer part, rather rigid and dry, retained the light brown color of boiled soy-bean; whereas the inner part, soft and sticky, showed dark brown color indicating severe chemical changes. (5) The aflatoxin producing mold, Aspergillus oryzae was isolated from one sample among 5 of Maeju loaves. In addition to the low probability of isolability from Maeju loaves samples, since this mold grew only in the outer layer of Maeju loaves with such a low population density, about $10^4/g$, perhaps the aflatoxin problem in Korean native soysauce may not be critical.

• YAKHAK HOEJI
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• v.3 no.1
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• pp.11-14
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• 1957

"Kotchujang" is a favorite food among the Korean. "Kotchujang" is a fermented food made from rice, red pepper, table salt, water, and "Maeju". "Maeju" is a fermented Soybean and is the fermentation source for Kotchujang. The freshly prepared Kotchujang is quite hot due to the hot component of red pepper, Capasaicin and it is getting to decrease the hotness resulting to the delicious and milder taste after fermation for some time (one to two months ususally at home). No one studied on this fermentation process on biochemical view-point yet.n process on biochemical view-point yet.

• The Korean Journal of Mycology
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• v.21 no.4
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• pp.247-272
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• 1993

Forty-eight fungal isolates were collected from the Korean traditional maejus and twenty-eight isolates of them were identified to be a hyphomycetous fungus(three genera and 20 species) Aspergillus flavus, A. flavus var columnaris, A. oryzae, A, oryzae var effusus, A. terreus, Scopula­riosis brevicaulis, Penicillium botryosum, P. gorlenkoanum, P. griseo-purpureum, P. citrinum, P. miczynskii, P. gaditanum, P. turolense, P. funiculosum, P. rubicundum, P. godlewskii, P. jensenii, P. roqueforti, P. volguense, P. verrucosum. Various 14 species of Penicillium were isolated from maejus, but all of them were not considered to be involved in the maeju fermentation. Otherwise, S. brevicaulis was especially collected from the maejus of various located areas, but were also related to the good quality of maejus under labratory conditions. A. flavus, A. oryzae P. tulolense, and P. funiculosum were also observed to be involved in the process of maeju.

• Korean Journal of Food Science and Technology
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• v.24 no.6
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• pp.581-585
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• 1992

To isolate zearalenone-producing strains from agricultural products in Youngnam districts, various samples such as rice(60), barley(52), soybean(45), peanut(33), corn(32), maeju(27), unhulled rice(UR, 40), unhulled barley(UB, 54), and soil(32) collected. From 375 samples, 302 Fusarium strains were isolated. The isolated strains were cultured for 14 days at $30^{\circ}C$ in rice medium, and then screened zearalenone-producing strains by TLC and HPLC. The result was that 29 isolates[rice(3), maeju(2), corn(1), barley(5), soil(4), peanut(3), soybean(4), U.B.(5), U.R.(2)] were screened as zearalenone-producing strains by TLC, while 19 isolates [rice(2), maeju(1), corn(1), barley(4), soil(3), soybean(2), U.B.(3), U.R.(3)] by HPLC method.

• The Korean Journal of Mycology
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• v.19 no.2
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• pp.148-155
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• 1991

Fungal ochratoxin A wes extracted and measured from the Korean traditional and fermented soybean foodstuffs (12 samples of Maeju, 28 samples of Dwangjang and 28 samples of Kangjang) collected from the whole nation wide regions. The various fungi were isolated from the foodstuffs and they were also examined whether the isolates produce ochratoxin A (OA) under the artificial conditions or not. Determinations of OA produced by the fungi were done with the antibody-attached CIA method, which was accurate or sensitive at the range of 20 pg per sample with a ninty percent recovery. Out of the 222 fungal isolates, 39 isolates produced the OA under the artificial conditions, and were identified as species of Aspergillus, Penicillium, Paecilom­yces or other genera. The OA detected in all soybean foodstuffs was presumed to be originated from the first fermentation step of maeju.

• Applied Biological Chemistry
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• v.14 no.2
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• pp.137-148
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• 1971

Studies were carried out to investigate the main fermentation microorganisms and their flora changes during Korean native soy-sauce fermentation. Korean native Maeju loaves collected from 5 Do's were separated into surface and inner parts. Four different soy-sauces-the surface part Maeju fermented soy-sauce, the inner part, the surface and inner part combined Maeju fermented soy-sauce, and the semi-Japanese type soy-sauce were fermented and the changes of fermentation microorganism flora and the various chemical components during the period of their fermentations were studied. Besides, 14 home-made soy-sauces collected from 14 different places all over Korea were examined in comparison with the laboratory soy-sauces and to determine the characteristics of Korean native soy-sauce. The results were as follows: 1. The main microorganisms in Korean native soy-sauce fermentation were determined as; Aerobic bacteria: Bacillus subtilis, Bacillus pumilus Lactic acid bacteria: Pediococcus halophilus, Leuconostoc mesenteroides Yeasts: Torulopsis datila, Saccharomyces rouxii 2. Microflora changes during Korean native soy-sauce fermentation were as follows; Aerobic bacteria increased until the 2nd week of fermentation and then gradually decreased. The lactic acid bacteria increased until the 3rd week, after which decreased. When the lactic acid fermentation lowered the pH value to below the 5.4, yeasts were able to grow and participate the fermentation. As the production of organic acids amounted, to a certain height, the growth of all microorganisms lead to the period of decline or death at about the 2nd month of fermentation. After boiling of soy-sauce most microorganisms except a few of Bacillus sp. disappeared. Occosionally yeasts and lactic acid bacteria survived depending upon the composition of soy-sauce. 3. Changes of general chemical components influencing the microflora were investigated for the period of Korean native soy-sauce fermentation. Tetal acidity, salt concentration and total nitrogen were increasing steadily over the entire period of fermentation. pH values were dropping to a certain degree of about 4.5. Salt concentration and pH value seemed to be the important factors influencing the microflora. 4. The microflora were influenced by chemical components of soy-sauce. Aerobic bacteria were able to survive in all soy-sauce as they made spores. Growth of lactic acid bacteria was inhited at 23-26% of salt concentration and pH 4.8. Soy-sauce yeasts started to grow only at pH below 5.4 and seemed to be inhibited at around 26% of salt concentration under pH 4.5-4.7. 5. The open kettle boiling of soy-sauce, the characteristic process of Korean native soy-sauce manufacturing, was effective to sterilize microorganisms, increase the salt concentration, and coagulate proteins. 6. The average viable cell counts of microorganism found in collected samples of home-made Korean native soy-sauces were; Aerobic bacteria: $53{\times}10^2\;cell/ml$ Lactic acid bacteria: 34 cell/ml Yeasts: 14 cell/ml The average values of chemical compositions of samples of home-made Korean native soy-sauce were; Salt concentration: 28.9% pH value: 4.79 Total acidity(lactic acid): 0.91g/100ml Total nitrogen: 1.09g/100ml

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.172-187
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• 1993

Forty eight fungal isolates were isolated from the maeius collected through the whole nation. Out of them, nine isolate were observed to be zygomyceteous fungi(4 genera and 9 species): Mucor hiemalis, M. circinelloides f. griseo-cyanus, M. circinelloides, M. jansseni, M. racemosus f. racemosus, Mortierella isabellina, Rhizopus stolonifer, R. oryzae, and Absidia corymbifera. Four species(M. circinelloides f. griseo-cyanus, M. hiemalis, M. jansseni, and R. oryzae) identified here were known as species involved in maeiu but not described in detail. The others were first reported as a species inhabiting in the maeiu. Two species of M. hiemalis f. hiemalis. and M. circinelloides f. griseo-cyanus were determined to play a role in biochemical changes of soybean in the fermentation of maeiu. However, the others seldom inhabited but considered to be comtaminated fungi in maeiu.

• Applied Biological Chemistry
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• v.19 no.2
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• pp.82-92
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• 1976

The study was carried out to investigate the changes of the various chemical components and the microflora during the aging period of Korean navive Kochuzang. (Red pepper soybean paste) Korean native maeju loaves were separated into surface and inner parts. Three kinds of Korean native Kochuzang were prepared from surface part, inner part, and ordinary of maeju. The selection and the indentification of the high enzyme producing strains from the microflora and characteristics of their enzymes were studied. I. The changes of the various chemical components during the aging period of Kochuzang. 1) The changes of pH in the 3 kinds of Kochuzang displayed rapid decrease for the first 10 days after preparing and gradual curve of decrease until 60 days, but slight increase for the next 30 days. The pH of the surface part Kochuzang was lower than that of inner part or ordinary Kochuzang. 2) The total acid contents in the 3 kinds of Kochuzang showed gradual increase until the 60 days but it slowly reduced after this time. 3) The total nitrogen contents in the 3 kind of Kochuzang showed gradual inerease up to the 60 days, but slight decrease after this time. 4) The changes of trichloroacetic acid soluble nitrogen in the 3 kinds of Kochuzang showed a remarkable increase for the first 10 days, however gradual increase after this time. 5) The increase of amino nitrogen contents in the 3 kinds of Kochuzang seemed to be remarkable until the first 30 days, however to be less remarkable after this time. 6) The contents of reducing sugar in the 3 kinds of Kochuzang showed remarkable increase until the first 50 days and it slowly reduced after this time. II. The changes of microflora during the aging period of Kochuzang. 1) Aerobic, anaerobic bacteria and mold in the 3 kinds of Kochuzang were increased until the first 30 to 40 days, but they were reduced after this time. 2) No yeast in the three kinds of Kochuzang appeared until the first 20 days. Yeast were proved to grow, when the pH value was decreased below 5.4 after the 30 days. Yeasts in the surface part and ordinary Kochuzang were gradually increased and those in the inner part Kochuzang were decreased as aging. III. The selection and identification of high amylase and protease producing strains from the microflora during the aging period of Kochuzang. 1) The amylase and protease highly producing strains from microflora were identified as Bacillus subtilis-P, Bacillus subtilis-G, Bacillus licheniformis-K, Aspergillus oryzae-B. 2) Amylase activity of Aspergillus oryzae-B was highest among the strains and the strains in order of the higher activity to the lower one were Bacillus subtilis-P Bacillus licheniformis-K, Bacillus subtilis-G. Protease activities of Aspergillus oryzae-B and Bacillus subtilis-P were about the same and the strains in order of the higher activity to the lower one were Bacillus licheniformis-K, Bacillus subtilis-G. 3) Amylase activity was inhibited more than protease activity was with NaCl concentration. Amylase activity was inhibited by 45 to 65 percent and protease activity by 40 to 46 percent at the concentration of 15 percent NaCl, which was the average concentration of NaCl in Kochuzang.