• Microbiology and Biotechnology Letters
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• v.39 no.1
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• pp.56-62
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• 2011

We investigated quality characteristics of Seoktanju (one of the Korean traditional rice wine) which was fermented using five kinds of Korean commercial Nuruks. The purpose of this study was to research what effects on the quality of Seoktanju by using different Nuruks. We analyzed general component such as each mash's temperature change patterns, pH, titrable acidities, reducing sugar contents, volatile acids, and sugar contents during fermentation periods and studied sensory evaluation of produced Seoktanju (10 days). On the whole, temperature change patterns in the each mashes were depend on room temperature. All Seoktanju's pH was reduced rapidly up to three days after first mashing (pH 3.13-3.57) and after that was increased gradually. The end of fermentation pH was pH 3.6-4.05. Mostly, acidities were indicated high(0.59%) and Nuruk-B was showed highest acid value. These results seems to be different as occasion organic acids producing activity depend on the number of yeast, material contents, optimal temperature in the each mashes by fungi and lactic acid bacteria in Nuruks. In reducing sugar contents and sugar contents, Nuruk-C treatment were showed the highest value with 5.36%, $23^{\circ}brix$, respectively and alcohol content was lowest with 8.6%. In the five kinds of reproduced Seoktanju, alcohol content was the highest in the treated Nuruk-A group. Volatile acid value was the highest with 132.6~263.7 ppm at the 3 day after first mashing day but as the fermentation time goes on, it was reduced sharply by 5.25~5.94 ppm. Sensory evaluation was performed with 5 point scale, the Seoktanju using Nuruk-D was presented by 4 point, while Nuruk-A was presented lowest by 2.77 point on overall acceptability.

• The Korean Journal of Mycology
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• v.41 no.4
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• pp.255-260
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• 2013

In order to develop new valuable pear marc nuruk and further, reduce environmental pollution by pear marc from pear juice processing, we prepared pear marc nuruk by incubation of Aspergillus oryzae into pear marc containing 50% of moisture at $30^{\circ}C$ for 7 days. ${\alpha}$-Amylase and glucoamylase activities of the pear marc nuruk were 320.2 IU and 442.8 IU, respectively and its acidic protease activity was showed 142.6 IU. After brewed makgeolli by using the pear marc nuruk, cooked rice and Saccharmyces cerevisiae, its physicochemical characteristics was investigated. Ethanol content of pear marc nuruk-makgeolli was 6.8% after fermentation at $25^{\circ}C$ for 10 days and also pear marc makgeolli showed 45.6% of antihypertensive angiotensin I-converting enzyme (ACE) inhibitory activity. In conclusion, pear marc nuruk had high amylase activity and pear marc-makgeolli had also good fermentation characteristics and antihypertensive ACE inhibitory activity. Therefore, it has the potential to become a new nuruk for brewing makgeolli.

• 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.

• Journal of Practical Agriculture & Fisheries Research
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• v.26 no.3
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• pp.23-31
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• 2024

This study aimed to establish a liquid fermentation process to increase the alcohol productivity of distilled soju using domestically grown sorghum. After preparing mash with different ratios of sorghum and rice, the optimal amount of raw material was determined, and sorghum pretreatment methods, enzyme types, and modified nuruk were tested. The soluble solids (°Brix) of the saccharification solution ranged from 3.00 to 25.20 for bacterial α-amylase and 4.20 to 20.80 for fungal α-amylase. Bacterial α-amylase was more suitable for starch saccharification. At 20% sorghum and 80% rice mash, the alcohol content was 15.11%, showing that soluble solids and alcohol content increased with higher rice content. When puffed sorghum was used with bacterial α-amylase, alcohol content rose to 16.55%, showing puffed sorghum is suitable for fermentation without a separate saccharification process. In mash with 20% puffed sorghum and 80% rice, adding modified nuruk resulted in alcohol contents of 16.73% and 16.28%, respectively, for groups with and without nuruk. The alcohol content of the distillate after vacuum distillation showed a similar trend, suggesting modified nuruk has little effect on alcohol productivity and requires further research. When modified nuruk was added, alcohol and esters increased, but sulfur compounds, which are perceived as off-odors, also rose. Therefore, it is better not to use modified nuruk in distilled soju made with sorghum. In conclusion, the process using 20% puffed sorghum, 80% rice, and bacterial α-amylase is deemed feasible for improving the productivity of distilled soju through liquid fermentation with puffed sorghum and enzymes.

• Journal of the East Asian Society of Dietary Life
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• v.1 no.2
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• pp.133-149
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• 1991

The contents of“Joo-chan”consist of eighty two items about alcoholics, a number of side dishes and soybean sauces. Interpreted content was classified and analyzed. Selected 52 items among those brewages, artless-brewing alcoholics, were distributed into 6 large patterns. The materials used for brewing artless alcoholics were regular rice, waxy rice, wheat and yeast(NURUK). Six patterns, grounded on these materials, were set one thing to another and analyzed.

• Journal of the East Asian Society of Dietary Life
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• v.2 no.1
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• pp.1-16
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• 1992

The contents of "Joo-Chan" consist of eighty two items abut alcoholics, a number of side dished and soybean sauces. Interpreted content was classified and analyzed. Selected 31 items among those brewages, compounded alcoholics, were distributed into 7 large patterns. The materials used for compounded alcoholics, were regular rice, waxy rice, wheat, yeast(NURUK), and compounded extra materials. Seven patterns, grounded on those materials, were set one thing to another and analyzed. analyzed.

• 한국균학회소식:학술대회논문집
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• 2015.11a
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• pp.11-11
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• 2015

A total of sixty-six samples of Nuruk, a fermention starter used to make the Korean traditional rice wine, Makgeolli, were collected from central and southern regions of Korea in 2013 and 2014. We classified two groups of the Nuruk samples, "commercial" and "home-made", according to the manufacturing procedure and purpose of use. Commercial Nuruks were made in a controlled environment where the temperature and humidity are fixed and the final product is supplied to Makgeolli manufacturers. Home-made Nuruks were made under uncontrolled conditions in the naturally opened environment and were intended for use in the production of small amounts of home-brewed Makgeolli. We obtained more than five hundred isolates including filamentous fungi and yeasts from the Nuruk samples followed by identification of fungal species. Also we stored glycerol stocks of each single isolate at $-70^{\circ}C$. We identified the species of each isolate based on the sequences of ITS regions amplified with two different universal primer pairs. We also performed morphological characterization of the filamentous fungi and yeast species through observations under the microscope. We investigated the major fungal species of commercial and home-made Nuruks by counting the colony forming units (CFU) and analyzing the occurrence tendency of fungal species. While commercial Nuruks contained mostly high CFU of yeasts, home-made Nuruks showed relatively high occurrence of filamentous fungi. One of the representative Nuruk manufacturers used both domestic wheat bran and imported ones, mainly from US, as raw material. Depending on the source of ingredient, the fungal diversity was somewhat different. Another commercial Nuruk sample was collected twice, once in 2013 and again in 2014, and showed different diversity of fungal species in each year. Nuruks obtained from the southern regions of Korea and Jeju island showed high frequency of yeast such as Saccharomycopsis fibuligera and Pichia species as well as unique filamentous fungus, Monascus species. S. fibuligera was easily found in many Nuruk samples with high CFU. The major filamentous fungi were Aspergillus, Lichtheimia, Mucor and Penicillium species. In order to further our understanding of the isolates and their potential industrial applications, we assayed three enzymes, alpha amylase, glucoamylase and acid protease from 140 isolates out of about five hundred isolates and selected about 10 excellent strains with high enzyme activities. With these fungal isolates, we will perform omics analyses including genomics, transcriptomics, metabolic pathway analyses, and metabolomics followed by whole genome sequencing of unique isolates associated with the basic research of Nuruk and that also has applications in the Makgeolli making process.

• Food Science and Preservation
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• v.24 no.5
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• pp.714-724
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• 2017

Soju is a Korean traditional distilled alcoholic beverage produced from mashes various crops and Nuruk which is cultured with wild microorganisms. This study was conducted to investigate rice-Soju brewing characteristics of yeasts isolated from Korean traditional Nuruk. The general components of rice (Hanarumbyeo) raw materials were 14.7 g of water, 6.8 g of crude protein, 0.9 g of crude lipid, 0.4 g of crude ash, and 76.5 g of carbohydrate in 100 g. Saccharifying and proteolytic activities in Hanarumbyeo ipguk (solid-state culture of Aspergillus luchuensis) were also determined. The alcohol content of the fermented wash from isolates was 15.37-16.58% (v/v), which is 16.7-36.0% higher than that of industrial yeasts (12.33-13.19%). Reducing sugar contents were 2.04-3.92 and 7.92-8.78 g/100 mL in the isolates and industrial yeasts, respectively. The isolated yeasts showed 25.2-52.7% higher yield of distillates (41% alcohol) compared to industrial yeasts. Forty-one components were detected in the rice distillated Soju (25% alcohol) and principal component analysis revealed differences between the isolated and industrial yeasts with respect to the contents of i-BuOH, isobutanal diethyl acetal, ethyl caprate, and tetradecanoic acid.

• Preventive Nutrition and Food Science
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• v.16 no.2
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• pp.142-149
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• 2011

The purpose of this study was to elucidate the physicochemical and microbiological properties of Korean traditional rice wine, Makgeolli, supplemented with black garlic extract during fermentation. Black garlic extract was diluted with distilled water to produce 0.5% and 1.0% black garlic solutions. Those solutions were then used to make rice solutions which included 2 kg rice, 40 g Nuruk (a fermentation starter), and 14 g yeast. After being mixed, the rice solutions were fermented for 7 days in a water bath at $28^{\circ}C$. The alcohol contents of the control, 0.5% and 1.0% black garlic Makgeolli were 16.9, 16.0, and 16.2%, respectively. Total acidity, total soluble solids, and color increased throughout the fermentation process. There was an increase of microorganisms throughout the fermentation period in all the samples. Glucose was the highest free sugar, and succinic acid was the highest organic acid detected in all the samples. Thirty nine volatile compounds were detected in black garlic Makgeolli.

• 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.