• Journal of the East Asian Society of Dietary Life
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• v.2 no.1
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• pp.17-33
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• 1992

Information about processing method of Kwahaju can get from the 41 kinds classical literature traditional yakju. The contents of those classical literature consist of sixty items about Kwahaju, number of art-less-brewed alcoholics and compounded alcoholics. Interpreted content was classified and analyzed. Selected 40 items, about Kwahaju among previous 60 items, compounded brewages, were distributed into two groups of alcoholics ; Seoul Kwahaju and Kimchun Kwahaju. Both group of alcoholics, grunded on the periodical conversion of processing method through four centuries were set one thing to another and analyzed. The materials used for Kwahaju, compounded alcoholics, were waxy rice mainley, regular rice, yeast(Nuruk), wheat, barley seedings and Soju, Kwahaju, usually, is brewed for worm or hot season and store up the alcoholics for summer. It should be reminded to be durable alcoholics, not soon pureficated out or needing repair.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.994-998
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• 2007

Changes in microflora, pH, reducing sugar content, lactic acid content, and ethanol content during Korean rice wine fermentation were investigated. Typical quality characteristics of Korean rice wine fermentation including pH, reducing sugar content, lactic acid content, and ethanol content were evaluated. While a fungus was not detected in our Korean rice wine mash, yeast was found to be present at fairly high quantities (1.44-4.76\;{$\times}\;10^8\;CFU/mL$) throughout the fermentation period. It is assumed that lactic acid bacteria (LAB) had effects on the variations of fragrance and flavor for traditional Korean rice wine. The main LAB during the Korean rice wine fermentation was determined and identified as a Gram-positive, straight rod-shaped cell. Genotypic identification of the isolated strain by amplification of its 16S rRNA sequence revealed that the isolated strain was most closely related to Lactobacillus plantarum (99%) strains without any other comparable Lactobacillus strains. Therefore, we designated the major LAB identified from traditional Korean rice wine fermentation as L. plantarum RW.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.125-130
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• 2006

In order to utilize non-commercial melon as alcoholic beverage material, in this study the optimum fermentation method and manufacture conditions were investigated and thereafter the properties of final product were determined. As for melon wine made with only melon juice, sensorial properties, particularly flavor, were not acceptable as alcoholic beverage. To improve the lack of melon wine, we made mash with cooked rice and Nuruk, and then added melon juice during fermentation. Acceptable sensorial properties were obtained in melon wine when 30% extract juice of oriental melon was added after 4 day of fermentation. The alcoholic beverage added melon juice showed much higher yellowness value than that without melon juice indicating that a clear yellow color similar to melon was actually observed in final product. Adding melon juice led little changes in amount and composition of free sugars, organic acids and amino acids and could improve sensorial properties.

• The Korean Journal of Food And Nutrition
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• v.22 no.4
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• pp.644-649
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• 2009

This study was conducted to determine the influence of cultural conditions such as temperature, time, water content, koji-thickness and agitation on the production of saccharifying amylase by Rhizopus sp. ZB9 isolated from Korean Nuruk during the preparation of rice koji, which is used in brewing Korean rice wines, Takju and Yakju. Rice kojies were made under different cultural conditions, and the saccharifying activities of each koji were tested. The temperature range suitable for the production of saccharifying amylase was $28{\sim}36^{\circ}C$. Based on the saccharifying activity and color, 60 hours of cultivation at $28^{\circ}C$ was believed to produce the optimum results. The water contents of steamed rice suitable for the production of saccharifying amylase were 35~40%. An increase in koji-thickness induced no adverse effects on the production of saccharifying amylase, but agitation-work during cultivation had a harmful effect.

• The Korean Journal of Food And Nutrition
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• v.23 no.1
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• pp.70-75
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• 2010

This study was conducted to determine the influence of culture conditions such as temperature, time, water content, koji-thickness and agitation on the production of organic acid by Rhizopus sp. ZB9 isolated from Korean Nuruk during the preparation of rice koji, which is used in brewing the Korean rice wines, Takju and Yakju. Rice koji was made under different culture conditions, and the acidity of each koji was tested. The temperature range suitable for the production of organic acid was $28{\sim}32^{\circ}C$, and 36~48 hours of cultivation at that temperature range seemed to produce the optimum results. The production of organic acid increased in proportion to the increase in water content of steamed rice from 25% to 60%. An increase in koji-thickness induced no adverse effects on the production of organic acid, and agitation-work during cultivation showed very beneficial effects.

• The Korean Journal of Food And Nutrition
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• v.23 no.3
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• pp.399-404
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• 2010

This study was conducted to determine the influence of culture conditions such as temperature, time, water content, koji-thickness, and agitation on the production of protease by Rhizopus sp. ZB9, isolated from Korean Nuruk, during the preparation of rice koji, which is used in brewing the Korean rice wines, Takju and Yakju. Rice koji was made under different culture conditions, and the proteolytic activity of each koji was tested. The temperature range suitable for the production of protease was $28~32^{\circ}C$. Based on the protease and color, 60 hours of cultivation at $28^{\circ}C$ was shown to produce optimum results. The production of protease increased in proportion to the increase in water content of steamed rice from 25% to 35%. An increase in koji-thickness induced no adverse effects on the production of protease, and agitation during cultivation showed beneficial effects.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.229-235
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• 2016

Korea has a long history of brewing traditional rice wine using a authentic starter culture called nuruk, which contains natural microbial flora. Because rice wine is consumed fresh without filtration, its viable cells contribute to the biological activities of the wine. In numerous studies, microbial strains isolated from rice wine have been screened for their functionalities, which were mainly probiotic properties and antimicrobial activities. Indeed, some lactic acid bacteria (LAB) were confirmed to have strong probiotic activities as well as other health-promoting effects. Moreover, some of the isolated probiotic strains produced functional compounds, such as exopolysaccharides and γ-aminobutyric acid. For antimicrobial activities, some LAB and yeast strains were identified to produce bacteriocins and killer toxins, respectively, with significantly broad spectrum of antimicrobial activity. These functional strains originating from traditional rice wine and their metabolites can be used directly for the production of value-added food products.

• Microbiology and Biotechnology Letters
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• v.45 no.4
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• pp.277-283
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• 2017

To produce sweet liquor without artificial sweeteners, 8 traditional rice pre-treatment methods (juk, beombeok, seolgitteok, gumeongtteok, mulsongpyeon, injeolmi, gaetteok, and godubap) were analyzed in this study. The formation of sugars with the help of ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase using nuruk as a substrate has been previously confirmed. During the early stages of the pre-treatment processes, the amount of maltose produced (in descending order of its concentration) by ${\alpha}$-amylase was observed to be as follows: gaetteok > seolgitteok > beombeok > mulsongpyeon > juk > injeolmi > gumeongtteok > godubap. However, changes in maltose concentrations with respect to the pre-treatment processes after 48 hours were observed to be as follows: injeolmi > beombeok = godubap > gumeongtteok > gaetteok = mulsongpyeon > seolgitteok > juk. Maltose produced using either ${\alpha}$-amylase or ${\beta}$-amylase showed similar results. Glucoamylase produced 10 mg/ml of glucose during the godubap process, which was the highest amount of glucose among all the methods. Moreover, when ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase were used concurrently, glucoamylase increased glucose production in the later stages. Therefore, the possibility of producing sweet liquor without employing artificial sweeteners was confirmed, even if the amount of sugar in the liquor varied with the pre-treatment process.

• Food Science and Preservation
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• v.23 no.2
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• pp.259-266
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• 2016

Bitter melon powder (BMP) was used in the preparation of rice nuruk (RN) and makgeolli as one of raw materials. RN containing BMP (BMP-RN) was prepared by adding 0~2.0% (w/w) BMP into rice. Fermentative microbial, and antioxidant characteristics of makgeolli were determined during the fermentation process. pH during fermentation decreased from 4.52 (0% BMP-RN), 4.93 (0.5%), 4.80 (1.0%), and 4.88 (2.0%) on the initial fermentation day (day 0) to 4.15, 4.30, 4.57, and 4.59, respectively, corresponding to increases in acidity from 0.64~0.70% to 1.17~1.28%, respectively. Soluble solid contents increased from an initial 2.2~4.4 g/L (day 0) to 9.0~9.3 g/L, and alcohol level increased up to 13.0% by the end of fermentation (day 7). Soluble phenolic contents increased from 0.92, 1.01, 1.32, and 1.41 mg/mL on day 0, to 1.85, 2.03, 2.24, and 2.48 mg/mL on day 7, respectively, while the levels of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activities and ferric reducing/antioxidant power (FRAP) assay increased from 46.95~70.04%, 55.33~74.13%, and 0.629~1.243 on day 0, respectively, to 54.98~83.4%, 70.34~92.39%, and 0.964~1.455 on day 7, respectively. Makgeolli made with BMP-RN had higher soluble phenolic contents and antioxidant activity than those of makgeolli made without BMP-RN. These results suggested that BNP-RN made a functional makgeolli.

• Food Science and Preservation
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• v.30 no.4
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• pp.669-682
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• 2023

The production of distilled soju by fermenting nonsteamed rice was evaluated using commercial enzyme products. White koji and modified nuruk had alpha-amylase activities of 31.90 U/g and 3,532.71 U/g, respectively, and gluco-amylase activities of 698.32 U/g and 4,899.58 U/g, respectively. The enzyme products had activities of 5,604.15-225,182.00 U/g and 13,517.41-120,822.41 U/g, respectively. At enzyme concentrations of >800 mg/L, the Chung-moo-purified enzyme had an alcohol productivity of ≥19%. Nurukzyme R400, Sanferm Yied, and Diazyme X4 exhibited alcohol productivities of >19% at concentrations of >600 mg/L. The alcohol content of the vacuum distillates was 41.31%-44.86%. The volatile component with the alcohol content adjusted to 25% was analyzed and principal component analysis was performed. The volatile components in white koji, Diazyme X4, and Sanferm Yield were similar. The modified nuruk treatment group had a relatively high ethyl lactate content compared to the white koji treatment group. The Nurukzyme R400 treatment group had high contents of butyric acid and ethyl butyrate. The Chung-moo-purified enzyme was characterized by a low component content. Thus, when enzyme products were used in nonsteamed rice fermentation, no effect on the alcohol productivity and quality of vacuum distilled soju was observed, suggesting that it can replace white koji and modified nuruk.