• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1168-1172
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• 2000

Fermentation characteristics for the production of honey wine with Saccharomyces sake, Saccharomyces bayanus and nuruk were investigated. Among the yeast strains and the mixture with nuruk tested, nuruk-Sacch. sake mixture and nuruk-Sacch. bayanus mixture showed higher alcohol production and better fermentability than the single strains. Total acid and pH did not change considerably during the whole period of fermentation. As the fermentation progressed, reducing sugar decreased rapidly until the 6 days of fermentation, while alcohol content increased rapidly during the same period. In fermentation of 6 days, honey wine consisted of about $7.5{\sim}8.1^{\circ}Brix$ of soluble solid, $22.7{\sim}31.8%$ of reducing sugar. Alcohol content were reached up to 12.5 and 13.1% for honey wine manufactured with nuruk-Sacch. sake mixture and nuruk-Sacch. bayanus mixture, respectively, relative to $5.2{\sim}7.2%$ of the single strains. Generally, honey wines prepared with the mixture of nuruk-yeast strains were fermented more efficiently than those with the single yeast.

• Microbiology and Biotechnology Letters
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• v.27 no.3
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• pp.236-245
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• 1999

Andong Soju is a Korean traditional distilled liquor brewed with Nuruk which is cultured with wild microorganisms. To provide useful information for scientific production and systematic quality control of traditional distilled liquor, the effects of mixed culture of the alcoholic yeasts and saccharifying molds isolated from the Nuruk, and mashes on the flavor and sensory characteristics were investigated. Distillate from mashes cocultured with Saccharomyces cerevisiae and Hansenula anomala using Mucor Nuruk was compared with distillate from mashes brewed with Andong Nuruk and with distillate from plant fermented mashes to analyze their flavor characteristics. The volatile flavor compounds in distillates were analyzed by GC and GC-MS using direct injection, solvent extraction, and purge & trap methods. Alcohols such as 3-methyl-1-butanol, 2-methyl-1-propanol, 1-propanol, and 2-phenyl ethanol; aldehydes such as acetaldehyde and 2-furancar-boxaldehyde; esters such as ethyl ester of acetic acid, hexanoic acid, octanoic acid, decanoic acid; alkanes, alkenes, ketone, sulfur, and pyrone compounds were detected. Alcohols were chief components of flavor compounds. No significant difference in overall acceptability test was shown among three experimental groups(p<0.05), but Nuruk-like aroma, Kaoliangchiew-like aroma, sweet taste, and well rounded mouthfeel showed significant differences among them(p<0.05).

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.737-746
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• 1995

Through the study of identification of filamentous molds isolated from 12 traditional Nuruk, collected from several regions in Korea, 78 strains of Absidia spp., including Absidia corymbifera, Absidia ramosa, and Absidia sp. of which specific names were not identified, 19 strains of Rhizopus spp. including Rhizopus cohnii, Rhizopus arrhizus, and Rhizopus oryzae, 8 strains of Circinella spp., 1 strain of Actinomucor sp., 49 strains of Aspergillus spp., including Aspergillus oryzae, Aspergillus flavus, Aspergillus flavus var. columnaris, Aspergillus wentii, Aspergillus candidus, Aspergillus fumigatus, Aspergillus niger, and Aspergillus foetidus, 2 strains of Cladospoyium spp. and 2 strains Botryotrichum spp., etc. total 159 kinds of filamentous molds were isolated and identified. There were many differences in numbers and distributions of filamentous molds from each Nuruk according to their collected region. Absidia spp. were most frequently isolated from every Nuruk sample. Aspergillus oryzae, Aspergillus candidus, and Rhizopus cohnii showed even distribution. Penicillium sp. and Mucor sp. were not detected. Actinomucor sp., Aspergillus foetidus, Botryotrichum sp., and Cladosporium spp., which have not been reported by far, were found. Amylase activities, pH stability of amylase, and acid productivity of isolated strains were compared.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.767-774
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• 1997

For the standardization and quality improvement of traditional Korean Nuruk, 120 strains of fungi were isolated from Nuruks and 18 strains of them were selected as strains analysing the amylase and flavor. The genera of these fungi were identified as Aspergillus sp. (14 strains), Penicillium sp. (3 strains) and Rhizopus sp. (1 strains) by the conventional slide culture. Most of these fungi showed a better productivity of the saccharogenic and dextrinogenic enzymes in raw wheat bran culture than in cooked wheat bran culture. The ability of acid and flavor production was good in the raw wheat bran culture, and aflatoxins were not produced under the same culture. Penicillium sp. and Rhizopus sp. had high cell growth and amylast activity. Mixed culture of Aspergillus sp. No.3-6 and Penicillium sp. No.7-7 revealed a high liquefying and saccharifying activity as well as high flavors production. These results indicated that these fungi was proper strains for making Nuruk of good quality.

• Mycobiology
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• v.39 no.4
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• pp.278-282
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• 2011

The objective of this study was to find useful fungi with ${\alpha}$-amylase activity from the Korean traditional nuruk for the quality of traditional Korean alcoholic beverage. In this study, 165 samples of traditional nuruk were collected from 170 regions throughout Korea and the fungi were isolated to a total of 384 strains. In order to investigate the effect of microflora on nuruk, ${\alpha}$-amylase activity, saccharogenic power (SP), starch hydrolysis activity and acid producing activity were evaluated. Ten strains were selected by ${\alpha}$-amylase activity, which ranged from 458.47 to 1,202.75 U/g. The size of the discolored zone for the starch hydrolysis activity of each fungus ranged from 0.3 to 2 cm. The SP of the 10 strains ranged from 228.8 to 433.4 SP. Of the 10 stains, three were identified as Aspergillus oryzae, two as Aspergillus flavus, two as Lichtheimia sp., one as Rhizopus oryzae and two as other strains. The total aflatoxins present in the nuruks were examined using enzyme-linked immunosorbent assay. The 10 nuruks had less than 1.11 ppb of aflatoxins.

• Journal of the East Asian Society of Dietary Life
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• v.2 no.1
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• pp.83-94
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• 1992

As the result of the research on the manufacturing procedure of Sogog-ju in the classical literature(35 kinds), it was found that Sogog-ju is usually brewed on the first Boar day of January and Sogog-ju base is added to it in about 7days and then the fermentation of Sogog-ju comes to end in about 21 days. The material grains out of 48 items, used in the first step of brewing Sogog-ju, are nonglutnous rice 47 items(98%), flour 20items(42%), somnuruk 9 items(19%) out of nuruk (fermenter) 48 items (100%) and nuruk water 5 items(17%), and flour 3 items(6%) are used, but fermenter nuruk is not used. When the grains are used in the first step of brewing, they are usually in the form of gruel and rice cake, and in the second step of brewing, they are usually made into steam water soaked rice. Nuruk, Which is largely used in the first step, is usually put after the processed grains get cold, but in the second step of brewing, it may be put into the still warm grains. There are hardly any cases when nuruk is used in conspicously small quantity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.1025-1030
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• 2006

In other to develop new functional doenjangs, two types of the isolated nuruk doenjangs were prepared with protease and amylase-producing Aspergillus oryzae D-2 and antihyperlipidemia Bacillus subtilis LK-12 and then changes of its quality and physiological functionalities were investigated during 2 months of fermentation and compared with those of the commercial nuruk doenjangs made by commercial Aspergillus oryzae and antihyperlipidemia Bacillus subtilis LK-12. ${\alpha}-Amylase$ activity of the isolated nuruk doenjangs during fermentation were decreased slightly, whereas proteases activities were increased significantly to $1.8{\sim}2.8$ Unit per mL after 1 month of fermentation. These ${\alpha}-amylase$ activities and proteases activities were similar with those of the commercial nuruk doenjangs. Amino-nitrogen content and reducing sugar content of the doenjangs after 2 months of fermentation were approximate $1.63{\sim}1.72\;mg%$ and $0.77{\sim}0.81%$, respectively. Antihypertensive angiotensin-Ⅰ converting enzyme inhibitory activities of the isolated nuruk doenjangs were slightly decreased from $85.6{\sim}87.2%$ to $84.0{\sim}85.1%$ after 2 months of fermentation and the commercial nuruk doenjangs were also significantly decreased from $85.7{\sim}88.0%$ to $69.1{\sim}79.7%$, lower than the isolated nuruk doenjangs. Fibrinolytic activity and HMG-CoA reductase inhibitory activity of the isolated nuruk doenjangs were very low and it were also similar with those of the commercial nuruk doenjangs. Antioxidant activity of the isolated nuruk doenjangs were showed $17{\sim}22%$, lower than that of the commercial nuruk doenjangs $(22{\sim}26%)$.

• The Korean Journal of Mycology
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• v.39 no.1
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• pp.78-84
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• 2011

To develop new functional traditional rice wines using Gugija and Liriope tuber as raw materials, screenings of optimal fungal nuruk and alcohol fermentative yeast for brewing of Gugija-L. tuber traditional rice wine were performed with investigation of optimal fermentation condition. Finally, we selected commercial SJ nuruk and Saccharomyces cerevisiae C-2 as optimal nuruk and yeast for Gugija-L. tuber traditional rice wine. Furthermore, a new antihypertensive and anti-gout Gugija-L. tuber traditional rice wine was produced when 3% of Jangmyong Gugija and L. tuber No.1 were added into cooked rice and then fermented at $25^{\circ}C$ for 5 days with SJ nuruk and S. cerevisiae C-2.

• Microbiology and Biotechnology Letters
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• v.43 no.2
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• pp.169-174
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• 2015

Nuruk has been used as fermentation starter in the alcohol industry for some time in Korea. Various bioactivities, such as antiproliferative and anti-obesity, of R4 nuruk made from Rhizopus oryzae KSD-815 have been previously reported. In this study, the hot water and ethanol extract of R4 nuruk and their subsequent organic solvent fractions were prepared, and their antithrombosis activities were evaluated. The ethylacetate fraction showed strong anti-coagulation activity, and the ethylacetate and butanol fraction from hot water extract demonstrated platelet aggregation inhibitory activity, without hemolysis against human RBC. Our results suggest that R4 nuruk has the potential to act as a new anti-thrombosis agent.

• Journal of Applied Biological Chemistry
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• v.63 no.3
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• pp.229-234
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• 2020

Beer production with rice or other malt substitutes suffers from a lack of suitable enzymes for saccharification. For this reason, rice nuruk (fermentation starter) was tested as a starch replacement for malt in the saccharification process of beer production. The results of this study show that the enzyme activities of rice nuruk made with brewing fungi were higher than those of malt. Saccharification and glucoamylase activities were high in Aspergillus awamori KCCM 30790 and α-amylase activity was high in Aspergillus oryzae CF1003. Overall, malt beer had significantly higher alcohol, pH, total acid, volatile acids, amino acids, free amino nitrogen, bitterness unit and ΔE than rice nuruk beer. Where as Aspergillus awamori KCCM 30790 beer had significantly higher soluble solids, reducing sugar than malt beer. According to a sensory evaluation, malt beer was better color, flavor and Aspergillus oryzae CF1003 beer was better taste, texture, overall acceptability than other beer. Therefore Aspergillus awamori KCCM 30790 beer was suitable considering enzyme activities (saccharification, glucoalmylase) and physicochemical characteristics (soluble solids, reducing sugar). And then Aspergillus oryzae CF1003 beer was suitable considering sensory evaluation (taste, texture, overall acceptability). Therefore rice nuruk like Aspergillus awamori KCCM 30790 and Aspergillus oryzae CF1003 were suitable as a substitute material that can replace for malt in beer proceccing.