• The Korean Journal of Food And Nutrition
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• v.6 no.2
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• pp.89-95
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• 1993

A Nuluk, a Korean traditional Koji for brewing, was made with wheat flour and Aspergillus oryzae L2 which had a good aroma and strong abilities In producing saccharogenic and dextrogenic enzymes. The cultural conditions for the production of saccharogenic and proteolytic enzymes were tested. The productivity of dextrogenic enzyme was improved when Nuluk was made with unsteamed wheat flour as compared with steamed one, but that of proteolytic enzyme was reduced. The addition of water containing 0.5% hydrochloric acid was unfavorable for the production of those two enzymes. The optimum ratio of water added to wheat flour for the production of those two enzymes was 28$^{\circ}C$ on the basis of wheat flour, The productivity of saccharogenic enzyme was enhanced when the Nuluk was molded after 20 hours of precultivation, but that of proteolytic enzyme was reduced as compared with no molding. The optimum temperatures for the production of saccharogenic enzyme and proteolytic enzyme were 36$^{\circ}C$ and 28$^{\circ}C$, respectively.

• Korean Journal of Food Science and Technology
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• v.46 no.1
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• pp.25-32
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• 2014

This study aimed to analyze the general ingredients and volatile compounds of ipguk (koji) and nuruk soju distilled under reduced pressure (RP) or atmospheric pressure (AP) conditions. After the secondary brewing process, soju made using ipguk had a final fermentation alcohol content of $18.0{\pm}0.6%$, whereas soju made using nuruk reached $14.3{\pm}1.7%$. The level of succinic acid was the highest in ipguk soju ($7,685.33{\pm}34.97$ ppm), but nuruk soju also showed a high level of succinic acid ($5,945.79{\pm}76.30$ ppm) after its final fermentation. In an analysis of fusel alcohol content, the level of n-propanol in ipguk soju (389.10-397.27 ppm) was similar under different RP (50 cm Hg and 60 cm Hg) and AP conditions ($80^{\circ}C$ and $90^{\circ}C$). Under RP and AP conditions, the isoamyl alcohol/isobutanol (A/B) ratio was similar, ranging from 1.32-1.35. In ipguk soju distilled under RP conditions of 50 cm Hg and 60 cm Hg, the amount of the toxic component, acetaldehyde, was 8.59 and 9.27 ppm, respectively. Under AP conditions, the amount of acetaldehyde in ipguk soju distilled at 80 and $90^{\circ}C$ was 9.80 and 10.63 ppm, respectively, indicating that the amount of acetaldehyde did not differ depending on the distilling method used. These results suggest that the liquor distilled from the mash produced using ipguk under RP conditions may be of a higher quality.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.379-383
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• 2018

Beer is the most popular alcoholic fermentation product, but its high purine content has been known to be associated with hyperuricemia and gout. In this study, we examined whether the purine content of beer could be lowered by changing the fermentation temperature during beer-brewing. We brewed beers at different temperatures, $10^{\circ}C$ and $20^{\circ}C$, that are two typical beer-brewing conditions for bottom- and top-fermentation, respectively, and the contents of the representative purines, adenine, guanine, and xanthine in each beer were measured by high performance liquid chromatography. As a result, the total purine content of the beer fermented at $10^{\circ}C$ was lower than that of fermented beer at $20^{\circ}C$. Especially, the content of adenine was lowered significantly.

• Applied Biological Chemistry
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• v.8
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• pp.45-50
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• 1967

Starch was liquefied by the bacteriological ${\alpha}-amylase$ and saccharified separately by four strains of mold as saccharogenic enzymes, then thise was fermented for research the fermentation rates, the usefulness of application of four strains of mold and the S.P to need in proportion increasing of concentration of mixed-starches for brewing in this experiment. The obtained results were as follows: 1) In the ability of saccharificatien, fermentation and acid resistance, Aspergillus usamii mut shirousamii, which were used to produce the koji, were excellent, however, Rhizopus delemar had heavy pollution in a lot of production of koji, were-as its qualities as enzyme was good. 2) The necessary S.P in proportion to the concentration of mixed-starch for brewing was found in this experiment in which was fermented in the various concentration of the adding S.P and the mixed-starches for brewing. 3) In the experiment of almost manufacture scale, the S.P needed essentially in the saccharogenic formentation was found and the usefulness of the necessary S.P was observed, and in fact in the manufacture scale it was safer to add the S.P more than 1.2% because it must be considered that the ability of enzymes is reduced by heat or acid. 4) The period of fermentation was shorten because the conditions for yeast propagation were excellent as a results of starches being liquefied by bacteriological amylase, and saccharified by molds as saccharogenic enzymes.

• Applied Biological Chemistry
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• v.36 no.4
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• pp.277-283
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• 1993

In order to brew foxtail millet wine, a folk wine of Cheju, properties of raw materials, optimum brewing conditions were inveatigated. Carbohydrate and crude fat content of glutinuous foxtail millet are 71.27% and 3.47%, respectively. Since the ratio of water to steamed millet and ethanol concentration of wine showed negative correlation, less than 250% water had to added to steamed millet to maintain ethanol concentration in wine above 13%, Sugar consumption and ethanol production increased rapidly for the first 2 days, and main fermentation was done in 4 days. Ethanol concentrations were $13.0{\sim}13.4%$ when foxtail millet was used, and they were $14.0{\sim}14.3%$ for the mixture substrates of 90% millet and 10% rice or barley. Organic acids in millet wine were lactic acid, malic acid and succinic acid. The residual carbohydrates after fermentation were mainly xylose and oligosaccharides. A trace of methanol was detected in millet wine. The content of fusel oil was low, while the concnetration of organic acids was high. Optimum conditions for millet wine-making were as follows. Glutinuous foxtail millet with 10% rice as fermentation source need to be soaked in water and steamed for enough time. Water was added to steamed millet with the ratio of 2 : 1. The resulting mixture was stmnultaneously saccharified and fermented by Aspergillus orzae and Saccharomyces cerevisiae IAM 4274 at $20^{\circ}C$ for a week. Millet wine was prepared after filtering fermented broth while pressing for a week.

• Mycobiology
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• v.38 no.2
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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.

• The Korean Journal of Food And Nutrition
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• v.6 no.2
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• pp.96-102
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• 1993

A Nuluk, a Korean traditional koji for brewing, was made with wheat flour and Rhizopus japonicus T2 which had a good aroma and strong abilities in producing saccharogenic and proteolytic enzymes, and cultural conditions for the production of those two enzymes were tested. The productivity of saccharogenic enzyme was markedly improved when Nuluk was made with unsteamed wheat flour as compared with that with steamed one, but that of acid protease was reduced. The addition of water containing 0.5% hydrochloric acid was unfavorable for the production of saccharogenic enzyme and neutral protease. The optimum ratio of water added to wheat flour for the production of saccharogenic enzyme and proteolytic enzyme was 28% on the basis of wheat flour. The productivity of saccharogenic enzyme was enhanced "when the Nuluk was molded after 10~20 hours precultivation but that of proteolytic enzyme was reduced as compared with no molding. The optimum temperature for the production of saccharogenic enzyme was 28f and that of proteolyic enzyme was also 28$^{\circ}C$. The optimum cultural time for the production of saccharogenic enzyme was 36 ~72 hours at 3$0^{\circ}C$ and that of proteolytic enzyme was 36 hours.ours.

• The Korean Journal of Food And Nutrition
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• v.7 no.1
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• pp.51-57
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• 1994

A nuluk, a Korean traditional koji for brewing, was made with wheat flour and Aspergillus usamii mot. shirousamii S1 which had strong abilities in producing amylase and protease. The cultural conditions for the production of saccharogenic and proteolytic enzymes were tested. The productivities of saccharogenic and dextrogenic enzymes were improved when nuluk was made with unsteamed wheat flour as compared with steamed one, but those of proteolytic enzyme and organic acid were reduced. The addition of water containing 0.5% of hydrochloric acid was unfavorable for the production of saccharogenic, dextrogenic and proteolytic enzymes. The optimum ratios of water added to wheat flour for the production of saccharogenic enzyme and proteolytic enzyme were 32% and 28%, respectively on the basis of wheat flour. The optimum temperatures for the production of saccharogenic enzyme and proteolytic enzyme were 36$^{\circ}C$ and 28$^{\circ}C$, respectively. The activity of saccharogenic enzyme reached its maximum after 120 hours of cultivation at 36$^{\circ}C$, but that of proteolytic enzyme 96 hours. The productivity of saccharogenic enzyme was enhanced when the nuluk was molded after 24 hours of precultivation but that of proteolytic enzyme was reduced as compared with no molding.

• The Korean Journal of Food And Nutrition
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• v.6 no.4
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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.

• The Korean Journal of Food And Nutrition
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• v.6 no.4
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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.