• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.302-306
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• 2014

Ehwa nuruk (EN), a traditional Korean alcoholic rice beverage, is manufactured from pulverized wet rice and the needles of pine trees. In this study, the ethanol extract of EN and its subsequent organic solvent fractions were prepared, and their in-vitro anti-thrombosis activity evaluated. In an anti-coagulation assay, only the ethylacetate (EA) fraction of the ethanol extract showed significant extensions of thrombin time, prothrombin time and activated partial thromboplastin time. In a platelet aggregation assay, the water residue of the ethanol extract exhibited aggregation inhibitory activity. Our results suggest that the EA fraction has potential as a new anticoagulation agent and EN could be used as a novel resource for anti-thrombosis agents. This report provides the first evidence of the anti-thrombosis activity of EN.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.2
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• pp.125-140
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• 2016

We analyzed the cultural characteristics of isolated brewing fungi for developing fermentation starters. In a previous study, we collected 87 domestic nuruk, from which 481 fungi strains were isolated and 11 were selected showing improved productivity. After culturing these 11 fungi strains in several types of media, temperatures, carbon and nitrogen sources, Rhizopus sp. grew well in MEA, ME20S, PDA medium while Aspergillus sp. grew well in ME20S and YES. Both Rhizopus sp. and Aspergillus sp. survived well at optimal growth temperatures of 30 and $37^{\circ}C$. Rhizopus sp. utilized lactose, glucose and peptone sources while Aspergillus sp. utilized glucose, mannose, fructose and yeast extract sources. ${\alpha}-Amylase$ activity was excellent in L. ramosa CN044, R. oryzae 82-7(MEB), R. oryzae CN174 and A. oryzae 58-11(WEB) culture extracts. This study suggests that R. delemar 26-4, 58-8 and A. oryzae 78-5, 37-7 might be appropriate fungi strains for fermentation starters based on development of large fungi bodies and their good enzyme activities.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.311-314
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• 2001

In order to develop a new Korean traditional liquor using acasia, the condition of alcohol fermentation was investigated by addition of 5%, 10%, 15% nuruk and 10% acasia into mash, The maximum amounts of ethanol was produced when 10% acasia flower and 15% nuruk was added in cooked rice and fermented by S, cerevisiae at $25^{\circ}C$ for 20 days, The acceptability and physiological functionalities of acasia liquors with different concentrations(5%, 10%, 15%, 30%. 50%) of acasia flower were compared. The A -15 liquor which was brewed by addition of 15% acasia flower into mash showed the best acceptability, and its electron-donating ability and nitrite-scavenging activity were also high.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.12-17
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• 2001

Aspergil-lus coreanus NR-15 and Aspergilus oryzae NR-2-5 from traditional Korean Nuruk were selected as parental strains producing starch hydrolysis enzyme. Xll(Arginine-) mutant from A. coreanus NR 15-1 showed high glu-doamylase activity and total acid productivity. Z6(Adenine-) mutant from A. oryzae NR2-5 showed the highest $\alpha$-amylase activity. Therefore, both XII and Z6 mutants were selected and investigated for the optimal conditions of protoplast formation for protoplast fusion. Mixture of equal amount of cellulase and driselase(10mg/ml each) was the most effective as lytic enzymes. The optimal pH and temperature for protoplast formation were 5.0 and $30^{\circ}C$, respectively. The most effective reaction for protoplast formation time was 4 hours. The maximum of protoplst for- mation of Xll mutant and Z6 mutant were $6.54$\times$10^{7}$ protoplasts/ ml and $3.04$\times$10^{ 7}$ protoplasts/ml, and the regen-eration frequencies of the protoplasts were 11.3% and 11.6%, respectively. The size of the protoplasts from X11 and Z6 mutants were 3~6 $\mu\textrm{m}$ and 4~9$\mu\textrm{m}$, respectively.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.3
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• pp.283-290
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• 2014

The present study was performed to obtain data that could be used to popularize yakju(Korean traditional rice wine) by surveying how well rice wine goes with pairing foods. The survey was given to 302 men and women living in the Seoul and Gyunggi areas and work in the food service industry. The Jeon group, Gui group, Jeongol and Jjigae group, Pyeonyuk and Bossam group, and Muchim group were selected as menu items that go well with available rice wines. The survey aimed to identify foods that go well with four rice wines with different sensory characteristics. The survey results showed that both men and women replied that rice wines with Nuruk aroma and Nuruk taste go well with the Jeon group, rice wines with sour and flower aromas and common characteristics go well with the Muchim group, and rice wines with sweet and fruit tastes go well with the Muchim group. However, men and women had different opinions on rice wines having ginseng, soil, and herbal medicine aromas. Men replied that such rice wines go well with grilled meat, whereas women replied that these rice wines go well with Pyeonyuk and Bossan groups.

• Microbiology and Biotechnology Letters
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• v.41 no.2
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• pp.168-175
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• 2013

In this study we investigated the possibility of preparing brewed brown rice makgeolli, a traditional Korean rice wine, under diverse conditions. For this purpose the physicochemical characteristics of makgeolli brewed at different temperatures, utilizing a variety of nuruks, the traditional Korean fermentation agent, were studied. The alcohol content was seen to be highest when brewing occurred at $30^{\circ}C$, with the nuruk TN producing 16.2%. At $20^{\circ}C$TN produced 14.1% alcohol content. The alcohol content was therefore higher, by about 2%, for $30^{\circ}C$ fermentations than $20^{\circ}C$ fermentations. Similarly, saccharifying activity was influenced by temperature and sugar content, with a higher activity seen at $30^{\circ}C$ than at $20^{\circ}C$. As the fermentations progressed acidification petered out, with titratable acidity being 0.50-0.67% in all end samples. On the Hunter L, a, b scale; the a value decreased slightly, while the b value increased steadily during the fermentation process. Measurements of total organic acids were highest at $30^{\circ}C$, with the nuruk AK, at about 550 mg%. The content of citric acid was the highest at $30^{\circ}C$, being 230-310 mg% in all samples. However, more lactic acid was detected at $20^{\circ}C$ than at $30^{\circ}C$. Total free amino acid was highest at $30^{\circ}C$, with TN at $8,605{\mu}g/ml$, AK at $6,083{\mu}g/ml$, and RJ at $2,381{\mu}g/ml$. Total free amino acid and essential amino acid was shown to be higher at $30^{\circ}C$ than at $20^{\circ}C$. The bioactive substance ${\gamma}$-aminobutyric acid was also higher at $30^{\circ}C$, with TN at $223{\mu}g/ml$. From all of these results, we surmise that brown rice makgeolli manufacturing conditions are optimal at $30^{\circ}C$ fermentation temperatures and using the nuruk TN for brewing vinegar. In addition, the nuruk used clearly affects the quality of brown rice makgeolli and an appropriate method to determine the best nuruk for various purposes should be pursued.

• Korean Journal of Food Science and Technology
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• v.53 no.3
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• pp.356-363
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• 2021

This study investigated the quality characteristics of anchovy sauce fermented using Nuruk to maintain a unique flavor, reduce fishy smell, and improve the fermentation rate. Six kinds of fermented fish sauces, including the control, fermentation using traditional Nuruk; SH Koji (Fs-A), JJ Koji (Fs-B), GJ Koji (Fs-C); and fermentation with improved Nuruk; Aspergillus luchuensis (Fs-D) and Aspergillus oryzae (Fs-E), were prepared. Samples were collected at 15 days intervals with 10% Nuruk added to raw anchovy and fermented at 25o C for 60 days. The free amino acids, especially glutamic acid content and amino nitrogen, were the highest in Fs-C, reflecting the high protease activity of Nuruk C (GJ). Regarding overall sensory evaluation, the control was the lowest, whereas Fs-C was highly evaluated among the sample groups. The addition of Nuruk not only shortened the fermentation period, but also increased the overall sensory level by adding umami and reducing fishy odor.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.239-246
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• 2005

Some characteristics of two forms of glucoamylase (glucan 1 A-$\alpha$-glucosidase, EC 3. 2. I. 3) purified from Aspergillus coreanus NR 15-1 were investigated. The enzymes were produced on a solid, uncooked wheat bran medium of A. coreanus NR 15-1 isolated from traditional Korean Nuruk. Two forms of glucoamylase, GA-I and GA-II, were purified to homogenity after 5.8-fold and 9.6-fold purification, respectively, judged by disc- and SDS-polyacrylamide gel electrophoresis. The molecular mass of GA-I and GA-II were estimated to be 62 kDa and 90 kDa by Sephadex G-1OO gel filtration, and 64 kDa and 91 kDa by SDS-polyacrylarnide gel electrophoresis, respectively. The optimum temperatures of GA-I and GA-II were 60$^circ$C and 65$^circ$C, respectively, and the optimum pH was 4.0. The activation energy (Ea value) of GA-I and GA-II was 11.66 kcal/mol and 12.09 kcal/mol, respectively, and the apparent Michaelis constants (K_{m}) of GA-I and GA-II for soluble starch were found to be 3.57 mg/ml and 6.25 mg/ml, respectively. Both enzymes were activated by 1 mM Mn^{2+} and Cu^{2+}, but were completely inhibited by 1 mM N­bromosuccinimide. The GA-II was weakly inhibited by 1 mM p-CMB, dithiothreitol, EDTA, and pyridoxal 5-phosphate, but GA-I was not inhibited by those compounds. Both enzymes had significant ability to digest raw wheat starch and raw rice starch, and hydrolysis rates of raw wheat starch by GA-I and GA-II were 7.8- and 7.3-fold higher than with soluble starch, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.4
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• pp.548-553
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• 2010

This study was carried out to compare the physicochemical characteristics of Korean traditional wines fermented by addition of sorghum (Sorghum bicolor) using different nuruks (SH and BS nuruk). The alcohol contents of the fermented wines ranged from 12.36 to 13.21%. The brix degrees of sorghum wines fermented using SH and BS nuruks were $8.6\sim17.9^{\circ}Bx$ and $7.6\sim20.0^{\circ}Bx$ on addition ratio, respectively. Wine no addedsorghum using SH and BS nuruks showed pH 3.74 and 3.40, total acidity of 1.40 and 1.51%, and 0.441 and 0.149 of turbidity. With increase of sorghum addition, brix degree, pH, turbidity and L-value decreased whereas total acidity and a-value increased. Total color difference (${\Delta}Eab$) parameters of wines fermented in 30, 70 and 100% sorghum addition using SH and BS nuruk were 4.33, 6.63 and 26.13, and 4.08, 5.29 and 10.59. Glucose content decreased with increasing amounts of sorghum. Organic acids such as lactic acid and acetic acid were predominantly detected in the fermented wine. Finally, based on sensory evaluations, the wine fermented by BS nuruk showed the best overall quality at 30% sorghum addition.

• Mycobiology
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• v.42 no.4
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• pp.353-360
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• 2014

Makgeolli is a traditional Korean alcoholic beverage. The flavor of makgeolli is primarily determined by metabolic products such as free sugars, amino acids, organic acids, and aromatic compounds, which are produced during the fermentation of raw materials by molds and yeasts present in nuruk, a Korean fermentation starter. In this study, makgeolli was brewed using the wild yeast strain Saccharomyces cerevisiae Y98-5, and temporal changes in the metabolites during fermentation were analyzed by ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry. The resultant data were analyzed by partial least squares-discriminant analysis (PLS-DA). Various metabolites, including amino acids, organic acids, sugar alcohols, small peptides, and nucleosides, were obviously altered by increasing the fermentation period. Changes in these metabolites allowed us to distinguish among makgeolli samples with different fermentation periods (1, 2, 3, 6, 7, and 8 days) on a PLS-DA score plot. In the makgeolli brewed in this study, the amounts of tyrosine ($463.13{\mu}g/mL$) and leucine ($362.77{\mu}g/mL$) were high. Therefore, our results indicate that monitoring the changes in metabolites during makgeolli fermentation might be important for brewing makgeolli with good nutritional quality.