• 한국식품영양학회지
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• 제6권1호
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• pp.1-7
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• 1993

19 Samples of koji-starters using in brewing were collected from Korea and Japan, and then 31 strains of koji-molds were isolated from them. After Identification of the Isolate, rice koji was made with each strains, and its saccharogenic activity, dextrogenic activity, proteolytic activity, acid Producing ability, browning reaction and flavor were tested. Among 31 strains of isolates, 10 strains were Identified as Asp nwamori var. kawachii, 18 strains as Asp. oryzae, 3 strains as Asp. usamii mkt. shirousamii. The koji-starters made in Korea were composed of single species of koji-mold with same strain, but those made in Japan were composed of the mixture of different two species or the mixture of different 2 ∼4 strains in same species. Judging from amylolytic and proteolytic ability by species, Asp. awamori var. kawachii H1, I1 and 11, Asp. owsae J2, L2, M2, P3 and P4, and Asp. usamii writ. shirousamii S1 were better than the others. Mold strains isolated from Korean koji-starters were much lower in amylolytic or proteolytic activity than those from Japanese koji-starters. The typical characteristics for the 3 species of koji-molds were that Asp. awamori var. kawachii was strong in acid producing ability, but week in amylolytic and proteolytic ability, that Asp. owzae had strong amylolytic activity and good aroma, but produced little amount of acid, and that Asp. usamii mut. shirousamii had strong Proteolytic activity but some off-flavor.

• 한국식품영양학회지
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• 제6권4호
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• pp.294-300
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• 1993

This study was carried out to investigate the influences of cultural conditions of koji on the production of saccharogenic amylase during rice-koji making by Aspergillus awamori var. kawachii which is now widely used as koji-mold in brewing Tikju and Yakju in Korea. The optimum cultural temperature for the production of saccharogenic amylase by this mold was 36$^{\circ}C$, and at this temperature it needed 40 hours of cultivation for maximum production of this enzyme. It was favorable for high production of both organic acid and saccharogenic amylase to shift the cultural temperature form initial 36$^{\circ}C$ to 32$^{\circ}C$ after 20~25 hours of cultivation. The production of saccharogenic amylase was low when the water content of steamed rice was below 35%, but its production was high at 40~60% of water content. When the quantity of conidial inoculation was too small, the production of saccharogenic amylase was low in initial phase, but it was retrived after 40 hours of cultivation. When koji-thickness was over 3cm, the production of saccharogenic amylase was markedly restricted. The saccharogenic amylase of this koji was stable at pH 2~7, and showed high activity at pH 2~5.

• 한국식품위생안전성학회지
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• 제22권3호
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• pp.137-144
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• 2007

우리나라의 전통발효식품의 기초가 되는 곡자는 날곡류에 Aspergillus속, Rhizpous속 등 곰팡이류 , 효모 기타 미생물이 자연적으로 번식하여 효소를 함유하는 것이고, 입국은 곡류를 증자한 후 Aspergillus속, Rhizopus,속 등 곰팡이를 번식시켜 효소를 함유하는 것이다. 식품첨가물공전 천연첨가물 중 국(입국) 시험항목에서 잡균(Penicillium속)의 오염확인이 어려워 새로운 곰팡이 시험법의 확립이 필요하다. 그래서 곰팡이 특유의 포자, 분생자병 또는 균사의 격벽유무 등의 관찰이 용이한 slide culture법을 확립하였다. Slide culture 법은 slide glass위에 정방형의 잘라진 배지를 놓고, 양쪽 모서리에 포자를 접종하고 배양되는 과정동안 포자, 균사체 및 격벽 등을 관찰하였다. Slide culture법을 이용하여 대표적인 식품 관련 곰팡이의 형태학적 특징을 확인하여, 시중에서 유통되는 수입 또는 국내 생산되는 곡자, 입국 등을 수거하여 Penicillium속 오염 여부를 모니터링하였으며, 그 결과 Penicillium속의 오염율은 0%였음을 확인하였다. 최종적으로 식품첨가물공전의 국 중 잡균시험법 등 곰팡이시험법 제 개정의 기초자료로 활용하고자 한다.

• 한국식품영양학회지
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• 제6권4호
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• pp.287-293
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• 1993

This study was carried out to investigate the influences of cultural conditions of koji on the production of organic acid during rice-koji making by Aspergillus awamori var. kawachii which is now widely used as koji-mold in brewing Takju and Yakju in Korea. The optimum temperature for the germination of the conidia of the mold was 35'8, and the time required for germination at this temperature was 8 hours. Rapid germination occurred when the water content of steamed rice was above 40%, but germination retardation occurred markedly below 35%. The optimum cultural temperature for the production of organic acid was 32$^{\circ}C$, and the production of organic acid was markedly restricted at 36$^{\circ}C$ and 4$0^{\circ}C$. It was effective for the high production of both saccharogenic amylase and organic acid to shift the cultural temperature from initial 36$^{\circ}C$ to 32$^{\circ}C$ after 20~25 hours of cultivation. Initial water content suitable to the production of organic acid was 40% in steamed rice, but its production was markedly restricted below 30% of water content. When the quantity of conidial inoculation was too small, the production of organic acid was low in initial phase, but it was retrived at later period. Acid production was markedly restricted together with the increase in koji thickness.

• 한국수산과학회지
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• 제51권4호
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• pp.369-375
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• 2018

This study investigated the effects of selected seaweeds on rice koji preparation (rice inoculated with Aspergillus luchuensis) and enzyme activity. Four types of rice koji were prepared using one of three seaweeds (0.5% laver, 0.5% kelp and 0.5% green laver) or a control for 72 h. The changes in the moisture content, water activity, pH, total mold cell count, amylase and protease activities were measured. During preparation, there was no significant difference in the moisture content among the four kojis, whereas the pH in the kojis made with either laver or green laver decreased rapidly compared with the control (P<0.05). This seemed to result from the seaweeds promoting the growth of mold cells. In terms of the activities of both amylase and protease, the koji with laver was superior. Subsequently, the amylase and protease activities of the koji made with laver were evaluated at various pHs (3 to 9), temperatures ($15-55^{\circ}C$) and NaCl concentrations (0-10%). The activities of both enzymes decreased notably at pH 9 and the protease activity decreased at temperatures above $45^{\circ}C$. Although the activities of both enzymes decreased at greater than 2.5% NaCl, activity was present at 10% NaCl.

• Applied Biological Chemistry
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• 제2권
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• pp.17-21
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• 1961

The manufacture of riboflavine fortified Dwen-Jang has been tried with an exceedingly riboflavine productive Aspergillus oryzae #612 mutant which has been developed by the authors. Both the rice and barley koji of this mutant and Aspergillus sojae have been prepared. Their riboflavine production, saccharifying and protease activities have begin compared The riboflavine fortified Dwen-Jang has been manufactured using the barley koji of riboflavine productive mutant. Their riboflavine content and qualities have been studied comparing with an ordinary Dwen-Jang which has been prepared with the barley kojo of A. sojae strain. The following results have been obtained. (1) The baley koji was superior in riboflavine production and protease activity, inferior in saccharifying ability than rice koji both with A. oryzae #612 and A. sojae. (2) In barley koji, the mutant, A. oryzae #612, produces 1.5 times riboflavine than A. sojae and shows stronger saccharifying and protease activities than the latter. (3) The riboflavine fortified Dwen-Jaug manufactured contained $5.2{\gamma}/g$ of riboflavine, about 1.5 times that of A. sojae. The higher contents of free sugar and free amjno nitrogen have been observed than the ordinary Dwen-Jang manufactured with A. sojae.

• 한국수산과학회지
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• 제55권3호
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• pp.267-277
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• 2022

This study investigated changes in the physicochemical and microbiological properties of fermented fish sauces based on the pacific sand lance Ammodytes personatus during fermentation according to rice koji treatments and salt contents. In total, six fish sauces were prepared, with rice koji treatment for 24 or 72 h before salt addition, and salt contents of 10 or 20%, including two controls to compare the response to different salt contents without koji treatment. The initial pH values of the sauces with koji treatments were notably lower than those of the controls. Over the 10 months of fermentation, the amino nitrogen contents of the sauces with 10% salt were higher than those with 20% salt, while the volatile base nitrogen value was also increased. In the microbial community, the initial numbers of lactic acid bacteria and mold were higher in the sauces with koji treatment than in the controls. After 8 months of fermentation, the free amino acid and organic acid contents were higher in the sauces with koji treatment than in the controls. Although the fermentation rate was affected to a greater extent by salt contents, the rice koji treatment also exerted a positive effect on the acceleration of fermentation.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 춘계학술대회 및 임시총회
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• pp.25-25
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• 2014

Koji molds are comprised of yellow, black and white. Black and white koji molds were recently re-visited by this author and it is concluded that they consists of Aspergillus luchuesnsis, A. niger and A. tubingensis, and the most important species for alcoholic beverage production is A. luchuensis. In the case of yellow koji mold, it is comprised of Aspergillus oryzae, A. sojae and A. tamari. In the case of A. sojae, the species is scarcely isolated from nature and rarely used for industry in Korea. Aspergillus tamari is often isolated from traditional Korean Meju, a fermented soybean product, and the classification of the species is clear. However, in the case of A. oryzae, differentiation between A. oryzae and A. flavus is still in controversy. In this study, we collected 415 strains of Aspergillus flavus/oryzae complex from air, rice straw, soybean, corn, peanut, arable soil and Meju in Korea and we examined the aflatoxin producing capacity of the strains. The norB-cypA, omtA and aflR genes in the aflatoxin biosynthesis gene cluster were analyzed. We found that 367 strains (88.4%) belonged to non-aflatoxigenic group (Type I of norB-cypA, IB-L-B-, IC-AO, or IA-L-B- of omtA, and AO type of aflR), and only 48 strains (11.6%) belonged to aflatoxin-producible group (Type II of norB-cypA, IC-L-B+/B- or IC-L-B+ of omtA, and AF type of aflR). In the case of A. flavus/oryzae strains from Meju, almost strains (178/192, 92.7%) belonged to non-aflatoxigenic group and only 14 strains (7.3 %) belonged to aflatoxin-producible group. It is proposed in this study that non-aflatoxigenic strain from Meju is classified as A. oryzae, considering that Meju is food material.

• Mycobiology
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• 제38권2호
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• pp.122-127
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• 2010

Different strains of mold were screened for the production of high quality Korean traditional rice wine with anti-hypertension and good acceptability. We isolated 867 nuruk mold strains and selected 24 for further study based on measurement of amylase activity. Among them, mold No. 17 showed high ethanol production upon fermentation with Saccharomyces cerevisiae as well as anti-hypertensive properties. The No. 17 strain was therefore selected as the functional mold and later identified as Rhizopus stolonifer based on molecular biological characteristics. Optimal fermentation conditions for the brewing of anti-hypertensive traditional rice wine comprised the addition of R. stolonifer No. 17 koji at a concentration of 35 sp/g and a fermentation period of 10 days at $25^{\circ}C$ using S. cerevisiae.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.340-341
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• 2006

High functional micro devices are demanded in a variety of fields. For realising such demands, development of high-precision micro-components installed in the devices are needed. To achieve high-precision in the mold processing of micro-components, the development of mold materials, i.e., the development of WC-Co hardmetal with higher hardness and fracture strength is essential, together with the developments of processing technology of high precision mold and mold-forming technology of high precision micro-components, etc. The role of development of the finer submicro-grained hardmetal in a NEDO national project aiming the integrated development of these all technologies and some results are mainly explained.