• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.12
• /
• pp.340-347
• /
• 2019

This study investigated the brewing properties of rice beer made with yeast isolated from traditional whole wheat nuruk. The experimental method was followed by alcohol fermentation and quality analysis for six months after separating the yeast from nuruk. The yeasts isolated from traditional nuruk showed normal fermentation characteristics, like those of commercial yeast, in terms of alcohol production capability, sugar content, and pH reducing power. Especially, the yeast (KCCM 301) isolated from whole wheat nuruk showed higher contents of glycogen and trehalose than that of commercial yeast, and so KCCM 301 yeast has excellent yeast vitality. Meanwhile, the yeast (KCCM 90301) isolated from traditional Nuruk produced significantly higher alcohol and ester contents than that of commercial yeast. This has a positive effect for supplementing the taste and aroma of rice beer. In conclusion, the yeasts isolated from whole wheat nuruk showed the general alcohol fermentation pattern and aroma content of rice beer. These yeasts seem to be effective in strengthening the flavor of rice beer.

• Journal of the East Asian Society of Dietary Life
• /
• v.2 no.1
• /
• pp.83-94
• /
• 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 Korea Academia-Industrial cooperation Society
• /
• v.17 no.8
• /
• pp.492-501
• /
• 2016

This study was conducted to investigate the physiochemical characteristics of Cheongju prepared using different types of rice (rice and glutinous rice) according to addition rate of Nuruk during low temperature fermentation. The characteristics of Cheongju prepared using three different temperatures ($10^{\circ}C$, $18^{\circ}C$, $25^{\circ}C$) were compared. After fermentation for 30-50 days, the pH of mash prepared at lower temperature was lower, as was that of mash made from rice relative to that prepared using glutinous rice. The total acidity was formed at lower temperature and generated in mashing prepared by glutinous rice. The organic acid content of mash made from rice at $18^{\circ}C$ was lowest, while that of mash prepared from glutinous rice was lowest at $10^{\circ}C$. The fermentation speed was lowest at $10^{\circ}C$; however, low temperature fermentation resulted in the highest alcohol content. The mash prepared from glutinous rice showed faster fermentation than that made from rice. In addition, the pH was lower when lower levels of Nuruk were added and higher in mash made from glutinous rice than that prepared from rice. The lower addition rate of Nuruk also showed a lower sugar content and final alcohol content. The levels of citric acid and lactic acid were higher, while those of succinic acid, acetic acid, and ethyl acetate were lower when lower levels of Nuruk were added. The mash prepared from glutinous rice showed a higher alcohol content than that made from rice.

• Journal of the East Asian Society of Dietary Life
• /
• v.21 no.6
• /
• pp.897-904
• /
• 2011

For set up the processing method of Byeo-Nuruk, we investigated the quality characteristics of Byeo-Nuruk according to the mixture ratio of rice and wheat, as well as the addition rate of moisture. After 12 hours of incubation, the temperature of Nuruk increased dramatically and reached a maxium temperature at 36 hours. After 36 hours, the temperature decreased gradually and was maintained at about $31{\sim}38^{\circ}C$. The ranges of pH and titratable acidity of Byeo-Nuruk were 4.85 to 7.42 and 1.0 to 2.3, respectively. A higher content of wheat ratio in Byeo-Nuruk, was associated with higher enzyme activities of ${\alpha}$-amylase, glucoamylase, and acidic-protease. Further, at a 70% wheat ratio, a 25% addition rate of moisture showed the highest enzyme activity. In the mixture ratio between rice and wheat, the 50:50 and 30:70 treatments contained the highest levels of microorganisms.

• Korean Journal of Food Science and Technology
• /
• v.34 no.2
• /
• pp.296-302
• /
• 2002

Quality characteristics of mash of takju prepared by wheat flour nuruks (conventional and improved style) were investigated during fermentation. Those were cultured with wild microorganism on whole and crushed wheat (wheat nuruk), wheat flour and mixture of rice and wheat flour, and nuruk cultured with Aspergillus oryzae on wheat flour. Ethanol content reached maximum of 10.6-17.4% after 14 days of fermentation. And the ethanol contents of takju were high in order of wheat nuruk, wheat flour nuruk, Aspergillus oryzae nuruk and mixture of wheat flour and rice nuruk. No difference of pH was among the treatments while the wheat flour nuruk cultured with wild microorganisms contained higher amounts of acids than the others. The amount of total sugars ranged from 16.22-17.74% on the starting day of fermentation, and decreased to 4.28-6.10% after 14 days. The amount of total sugars in mashes brewed with wheat flour nuruk cultured with Aspergillus oryzae was measured to be highest at the beginning stage of fermentation. Afterwards no difference was found among the types of nuruks. Glucose was in the range of 2,735-7,842 mg% at initial period of fermentation, afterwards it was rapidly decreased. The total amounts of free sugar for control and the wheat flour nuruk was higher than other treatments. The total amounts of organic acids were the highest in wheat nuruk to 690-2,241 mg% and the contents of lactic acid and succinic acid were high in mixed rice nuruk to 183-1,293 mg%. The contents of lactic acid and succinic acid were higher than those of the other kinds of organic acids in takju.

• Food Science and Preservation
• /
• v.19 no.1
• /
• pp.144-152
• /
• 2012

The temperature changes and quality characteristics of $Makgeolli$ produced using rice treated with $Gaeryang-Nuruk$ (commercial improved $Nuruk$) extract were investigated. During fermentation, the treated rice maintained a lower temperature than the control and then rose after the fifth mashing day. For all the treatments, the numbers of yeast, LAB and AAB colonies increased on the second mashing day, and then gradually decreased. As the fermentation proceeded, the pH gradually increased from the third mashing day, and eventually became higher than that on the initial mashing day. The total acid contents increased on the first mashing day, but as the fermentation progressed, they showed little change. The amino acidity and soluble solid contents during overall fermentation and reducing-sugar contents was reduced until the first mashing day, and increased from the day after. As for the alcohol content, that of the control was 6.87% on the first mashing day, and then gradually increased, nuruk-extract-treated rice began with 9~10% alcohol content and then increased as the fermentation proceeded. Among the organic acid contents, lactate was the main material. In the sensory evaluation, the 24 h-, 48 h- and 72 h- treated rice samples showed somewhat good response.

• Microbiology and Biotechnology Letters
• /
• v.38 no.1
• /
• pp.46-52
• /
• 2010

Yakju, a Korean traditional alcoholic beverage, is made from glutinous-rice flour or rice starch with nuruk. In this study, we investigated that fermentation characteristics in yakju was made with glutinous rice and pretreatment. The yeast and nuruk were used Y90-9 and SP1800 (a kind of improved nuruk), respectively. pH and brix degree of yakju, brewed with glutinous rice flour by heating, were higher than the others during fermentation process. Total acid contents were 0.2~0.3 and the highest alcohol degree (15.75%(v/v)) was fermented glutinous rice flour by heating. Reducing sugar contents were 3.5-3.9 mg/mL. Yakju, which brewed with glutinous rice flour, of amino acid degree, UV absorbance and color degree was higher than yakju which brewed with glutinous rice starch. Succinic acid was the highest organic acid among 6 organic acids and free sugar contents described as glucose > maltose > fructose. Twenty one components were identified including 3 alcohols, 17 esters and one aldehyde. Of these, ethyl palmitate, which was described as mild flavor, was the highest %area except ethyl alcohol. Overall, the fermentation performed using glutinous rice flour by heating and improved-nuruk showed the best results for yakju production.

• Journal of the East Asian Society of Dietary Life
• /
• v.1 no.1
• /
• pp.1-16
• /
• 1991

Baekhaju is commonly called Bangmoonju. However comparing Baekhaju while Baekhaju used distiller's grains, Bangmoonju did not use them. Baekhaju used only nonglutinous rice, however, Bangmoonju used glutinous rice or a mixture of glutinous rice and nonglutinous rice. Baekhaju in Chinese, which was misrecored on Baekhaju in Korean from 15th century. However, Baekhaju should be distingnish from Baekhwaju, which is made buy addition of many flowers in various wine. Baekhaju used distiller's grains in the first step of its manufacture procedure. For the fermentation of Baekhaju, one of the three bases, which are rice gruel, rice cake or 구멍떡 was added to distiller's grains. Flours and nuruk are also added. In the second step, steamed water-soaked rice and nuruk was added up to the Baekhaju-base which was got from the first step.

• Journal of the East Asian Society of Dietary Life
• /
• v.21 no.6
• /
• pp.877-881
• /
• 2011

This study was investigated the quality characteristics of Makgeolli containing different types of Nuruk grain inoculated with A. oryzae N041. In an analysis of the quality characteristics of four types of Nuruk grain, mung beans Nuruk grain had higher acidity, amino acidity and saccharogenic power than rice Nuruk grain. In an analysis of four types of brewed Nuruk grain, mung beans Nuruk grain had the highest sugar and reducing sugar contents. On the other hand, mung beans Nuruk grain had the lowest alcohol content. Citric acid, malic acid and succinic acid have been identified as the major organic acids in Makgeolli. The amounts of organic acids were 1,748.5 mg% in rice Nuruk grain, 1,553.9 mg% in mung beans Nuruk grain, 1,003.2 mg% in barley Nuruk grain and 940.8 mg% in adlay Nuruk grain. In particular, Makgeolli brewed with mung beans Nuruk grain had the highest content of the organic acids, which is expected to deepen its flavor.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.12
• /
• pp.1702-1710
• /
• 2010

Korean traditional rice wines yakju and takju are generally brewed with nuruk as the source of the saccharogenic enzymes by natural fermentation. To improve the quality of Korean rice wine, the microorganisms in the nuruk need to be studied. The objective of this research was to improve the quality of Korean wine with the wild-type yeast strains isolated from the fermentation starter, nuruk. Only strain YA-6 showed high activity in 20% ethanol. Precipitation of Y89-5-3 was similar to that of very flocculent yeast (>80%) at 75.95%. Using 18S rRNA sequencing, all 10 strains were identified as Saccharomyces cerevisiae. Volatile compounds present in yakju were analyzed by gas chromatography-mass selective detector. The principal component analysis (PCA) of the volatile compounds grouped long-chain esters on the right side of the first principal component, PC1; these compounds were found in yakju that was made with strains YA-6, Y89-5-3, Y89-5-2, Y90-9, and Y89-1-1. On the other side of PC1 were short-chain esters; these compounds were found in wines that were brewed with strains Y183-2, Y268-3, Y54-3, Y98-4, and Y88-4. Overall, the results indicated that using different wild-type yeast strains in the fermentation process significantly affects the chemical characteristics of the glutinous rice wine.