• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.50-54
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• 1998

Ethyl caproate is one of the important flavor compounds produced during the brewing of rice wine. The rice wine yeast and koji were reported to produce the esterases which synthesize and also hydrolyze ethyl caproate. From the results of monitoring the esterase activities of rice wine yeast and koji, their roles for producing ethyl caproate during brewing were postulated. In case of rice wine yeast, the production of esterase synthesizing ethyl caproate was influenced by the substrate, caproate but that of esterase hydrolyzing ethyl caproate was promoted by ethyl caproate but inhibited by caproate. The production of esterases of koji were not influenced by the substrates for ethyl caproate production but influenced by the growth of koji. The maximum concentration of ethyl caproate produced by rice wine yeast was 0.4 ppm in this research but the production of ethyl caproate by koji was not detected under our experimental conditions. Considering the results of this research, ethyl caproate is not produced by the esterases of koji during brewing but produced by the esterases of rice wine yeast. The growth of rice wine yeast represses that of koji because of the high concentration of ethanol produced by rice wine yeast. The esterases of rice wine yeast may decide the production of ethyl caproate during brewing.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.830-834
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• 2003

The optimal condition for the production and extraction of monacolin K was reported. HPLC was used to determine monacolin K a kind of metabolite of Monascus from red-koji made of Monascus purpureus CBS 281.34. After culturing Monascus in solid and liquid media at $30^{\circ}C$ for 10 days, each of these were inoculated with soybean, wheat, barley, waxy rice, and rice and cultivated at $30^{\circ}C$ for 11 days. The production of monacolin K was the highest(0.35g/100g) when cultured with rice. The yield of monacolin K in red-koji increased with drying temperature and time according to the removal of water. Considering monacolin K content and the degree of death of Monascus, red-koji was dried at $80^{\circ}C$ for 60 min. Although monacolin K in red-koji was mostly extracted by 80% ethanol, there was no difference in monacolin K between shaking for 1 min and extraction for $0{\sim}24$ hr after sonication for 7 min. The extracted yield of monacolin K was the highest when the ratio of red-koji and 80% ethanol was 1:9. Moreover, the production of monacolin K appeared to be parallel with that of the pigment.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.125-131
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• 2000

Quality characteristics of kochujang prepared with meju, koji and mixture of the two(meju+koji) were investigated during fermentation to improve quality of kochujang. During fermentation of kochujang, moisture content was in the range of $53.4{\sim}66.5%$, salt was $8.3{\sim}10.1%$, crude protein was $8.3{\sim}19.3%$ and pH of kochujang was $4.6{\sim}5.4$. Amino-nitrogen content increased during fermentation and the levels were $230{\sim}270\;mg%$ after 150 days of fermentation. The highest amino-nitrogen content was found in mixed kochujang at the beginning stage of fermentation, but in koji kochujang after 30 days of fermentation. Maximum reducing sugar content was $15.0{\sim}19.5%$ at 60th day of fermentation. The highest amino acid content of kochujang protein was found in meju kochujang followed by koji kochujang at the first stage of fermentation. The content of glutamic acid, a major amino acid was $1.38{\sim}3.66%$ of total amino acid content. High levels of aspartic acid, leucine, arginine, alanine and phenylalanine were found in the kochujangs. Mixed kochujang showed the highest L value among the samples until 30 days of fermentation. After that, the highest L value was found in meju kochujang. The highest degree of redness was observed in meju kochujang until 60 days of fermentation and in koji kochujang during $90{\sim}120$ days of fermentation.

• The Korean Journal of Food And Nutrition
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• v.22 no.1
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• pp.86-91
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• 2009

To develop a new traditional Gugija tagju, various koji were prepared using several starch sources along with Aspergillus awamori var. kawachi, and then their effects on the quality of the tagju were investigated. Ethanol contents(11.1${\sim}$13.8%) were not significantly different among the Gugija tagju made from the various types of koji, whereas the tagju made using non-glutinous rice koji had the best total acceptability. The addition of 1% Gugija extracts into the mash increased its total acceptability and anti-hypertensive angiotensin I-converting inhibitory activity, and the optimal fermentation period for brewing the Gugija tagju was 10 days.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1979.10a
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• pp.243.2-243
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• 1979

현재 우리나라의 탁약주 용 Rice-Koji 제조 용종국균으로 널리 분양되고 있는 분양되고 있는 fawachi, S-27 균주가 생성하는 Amylase의 효소학적 특성과 Rice-Koji i제조 시 유기산 및 당화 효소의 생성 조건을 검토했다. 1. 본 균은 유기산 생성력이 강하고 또 생성하는 당화효소 및 액화효소는 내산성이 극히 강하며 pH3~5의 범위내에서 최고 활성을 나타내었으므로 탁약주 제조 용 종국균으로 아주 적합하였다. 2. 본 균의 발아 최적온도는 36$^{\circ}C$이었으며 Rice -Koji제조시 제국시간을 40시간으로 볼 때 유기산 생성의 최적온도는 32$^{\circ}C$이었고 당화효소 생성의 최적온도는 36$^{\circ}C$이었으며 고온인 4$0^{\circ}C$에서는 유기산 생성이 극히 불량하였다. 3. Rice-Kojiw제조시 당화효소의 생성은 배지의 수분함량 35%일 때 최고치를 보였으며 유기산 생성은 이 보다 높은 조건인 수분함량 40%일 때 이었고 비교적 건조한 조건인 수분함량 30%일 때는 유기산 생성이 특히 불량하였다. 4. 배지의 두께가 3cm이상이 되면 유기산 및 당화효소 생성에 않은 지장을 주었다. 5. 종국균의 점종량은 유기산 및 당화효소의 생성에 별로 영향을 미치지 못했다.

• KSBB Journal
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• v.30 no.1
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• pp.33-37
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• 2015

Recently, several health benefits of rice wine, makgeolli, were known due to the interest on the traditional Korean liquor and the researches on the rice wine are increasing. Organic acids produced during the process of rice wine fermentation play important roles in the taste and flavor. In this study, we have examined the optimal conditions for lactic acid production in rice koji as a carbon source. Skim milk was also used as a supplementary ingredient for the optimization of lactic acid fermentation. Bacterial growth of Lactobacillus sakei was monitored under this condition. The pH, acidity of the culture and the ethanol tolerance of this bacterium were also tested. Through these experiments, we were able to optimize the growth condition of lactic acid bacteria by the addition of skim milk. This was also able to affect the change of pH, acidity, sugar concentration and alcohol tolerance, which might contribute to the improvement of the quality of rice wine. The optimal condition for the growth was 2 days with 10% (w/v) of skim milk concentration. With these results, it was confirmed that rice koji was an effective carbon source for the growth of lactic acid bacteria.

• Journal of the Korean Society of Food Culture
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• v.6 no.3
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• pp.245-249
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• 1991

This study was conducted to establish traditional manufacturing process of Hongju, a traditional spirit by traditional Kokja and Koji method based on different materials. In the fermentation process, the changes of temperature, pH, total acid, alcohol, total sugar and microflora in mash were analyzed. During the whole fermentation period, the temperature in mash made by Kokja method was reached to $30^{\circ}C$, and that of Koji method was reached $33^{\circ}C$. There was no significant difference in pH by different treatments and the initial pH in Koji method was pH 6.0 and the final pH was 4.0. The content of total acid was higher in mash processed by Kokja method than that of Koji method. Alcohol content was higher in mash processed by Koji method. The content of total sugar in all samples were reduced gradually according to progress of fermentation. Yeast populations in all samples were increased up to 6 days of fermentation and then decreased gradually. Lactic acid bacteria were increased until 3 days of fermentation and then decreased until the fermentation completed.

• Applied Biological Chemistry
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• v.2
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• pp.23-28
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• 1961

The enzymic activities of Kojis which were prepared by the various combination of raw-materials, soybean and barley, were measured and the ripening process of soybean paste made from the kojis was pursued. 1). The koji made by the admixture of soybean, barley and wheat at the ratio of 40-60 : 60-40:20 was superior to the Kojis made from soybean or barley alone, in the aspect of dextrinizing, saccharifying and proteolytic activities. 2). The soybean paste mashed with the admixed koji with higher enzymic activities caused the more and rapid formation of reducing sugars and proteolysis than the soybean pate from barley-koji. 3). The effect of salt on the activities of ${\alpha}-amylase$, saccharification and proteases was examined and it was noticed that the three was inhibited to the different extent respectively.

• Microbiology and Biotechnology Letters
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• v.8 no.4
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• pp.247-253
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• 1980

This experiment was carried out to improve the method of koji preparation by using stainless steel frays which were specially designed and covered with lids. To elucidate changes in chemical composition and formation of enzymes during the preparation of koji with glutinous rice for red pepper paste. professes, amylases, reducing sugars, nitrogens, and microbial contaminations were determined and compared with the case of using trays without lids. The results obtained were as follows. 1. The activities of protease and amylases (both liquefying and saccharifying activities) during the koji preparation were found to be higher incase of using the trays with lids than that without lids. 2. The contents of moisture, soluble nitrogen, amino nitrogen, and reducing sugar were also higher in case of using the trays with lids. 3. Contamination by yeasts and bacteria were markedly low in the trays with lids. 4. Temperature of koji was higher in the trays with lids, however the level of moisture loss was 1ower.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.167-177
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• 1990

Rapid production of sardine sauce using sardine meal koji and autolysate from sardine meat was investigated. The sardine meal koji was prepared by mixing sterillized sardine meal with $10\%$ flour and $10\%$ soy sauce koji, and cultivating the mixture for 48hrs at $30^{\circ}C$ and $80\%$ R. H. For sardine autolysate preparation, chopped sardine was mixed with water (10:8= sardine:water, w/w) and autolyzed for 6hrs at $550^{\circ}C$. The optimum temperature and salinity were $40^{\circ}C$ and $15\%$ for rapid fermentation of sardine sauce. Sardine sauce were prepared experimentally under 10 kinds of conditions and fermented for 20 days. The excellent effects of sardine meal koji and autolysates from sardine meat on rapid processing of sardine sauce were showed in enhancing its flavor and advancing of nitrogenous compounds.