• Journal of Microbiology and Biotechnology
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• v.27 no.5
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• pp.896-908
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• 2017

In this study, a total of 58 different kinds of nuruk (a traditional Korean fermentation starter) were prepared, including 46 kinds of restored nuruk from ancient documents. Each nuruk was evaluated by analysis of its saccharification power, and the enzyme activities of glucoamylase, ${\alpha}$-amylase, ${\beta}$-amylase, protease, and ${\beta}$-glucanase. The range of saccharification power (sp) of the restored nuruk ranged between 85 and 565 sp. The diastatic enzymes, ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase, were significantly correlated to the saccharification power value; conversely, ${\beta}$-glucanase and protease did not have a correlative relationship with saccarification power. In addition, their brewing properties on chemical and organoleptic aspects of traditional alcoholic beverage production were compared. Each raw and supplementary material contained in nuruk showed its own unique characteristics on Korean alcoholic beverage brewing. For the first time, in this study, the traditional Korean nuruk types mentioned in ancient documents were restored using modernized production methods, and also characterized based on their brewing properties. Our results could be utilized as a basis for further study of traditional alcoholic beverages and their valuable microorganisms.

• Mycobiology
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• v.45 no.2
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• pp.119-122
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• 2017

Herein, nuruks derived from non-glutinous and glutinous rice inoculated with Aspergillus oryzae N159-1 (having high alpha-amylase and beta-glucosidase activities) were used to produce Korean alcoholic beverages. The resultant beverages had enhanced fruity (ethyl caproate and isoamyl alcohol) and rose (2-phenethyl acetate and phenethyl alcohol) flavors and high taste scores.

• Mycobiology
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• v.42 no.4
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• pp.361-367
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• 2014

Makgeolli, also known as Takju, is a non-filtered traditional Korean alcoholic beverage that contains various floating matter, including yeast cells, which contributes to its high physiological functionality. In the present study, we assessed the levels of ${\beta}$-glucan and glutathione in various yeast strains isolated from traditional Korean Nuruk and selected a ${\beta}$-glucan- and glutathione-rich yeast strain to add value to Makgeolli by enhancing its physiological functionality through increased levels of these compounds. Yeast ${\beta}$-glucan levels ranged from 6.26% to 32.69% (dry basis) and were strongly species-dependent. Dried Saccharomyces cerevisiae isolated from Nuruk contained $25.53{\mu}g/mg$ glutathione, $0.70{\mu}g/mg$ oxidized glutathione, and $11.69{\mu}g/g$ and $47.85{\mu}g/g$ spermidine and L-ornithine monohydrochloride, respectively. To produce functional Makgeolli, a ${\beta}$-glucan- and glutathione-rich yeast strain was selected in a screening analysis. Makgeolli fermented with the selected yeast strain contained higher ${\beta}$-glucan and glutathione levels than commercial Makgeolli. Using the selected yeast strain to produce Makgeolli with high ${\beta}$-glucan and glutathione content may enable the production of functional Makgeolli.

• 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.

• 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.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.23-23
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• 2014

There are many yeast strains have been discovered for industrial usage in global scale. In the point of view for the alcoholic fermentation performance and producing alcoholic beverage products, recently many countries have known about the importance of microorganisms as a valuable resource. Discovered with well performed yeasts have potential industrial application in diverse ways such as foods, beverages, cosmetics, pharmaceutical functions, and so on. In Korea, the yeast research has not been sufficiently performed especially for distilled spirits industry. As a result, not so little manufacturers use exotic yeasts from overseas even included the expensive royalties. Besides of those, to produce distilled spirits, many manufacturers do not use specialized yeast for distilled spirits. Distiller's characterized yeasts such as whisky, brandy, vodka, Japanese shochu and awamori, are all well-known industrialized. For decades, the distillers, except us, have selected, developed, and practised yeasts in accordance with distilled spirits characters. This study is about selection and industrial application of yeasts for the Korean pot distilled spirits. Finally 7 yeast strains were selected among over 1,000 yeasts from the traditional Nuruks, through the essential related tests based on brewing and distilling science. The selected yeasts show the appropriate characteristics of distilled spirits. The result of this study could help our distilled spirits industry be activated and stand independent from the exotic microbes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.5
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• pp.598-604
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• 2008

This study was carried out to develop a new traditional alcoholic beverage by using lily scale in order to utilize lily scale as a new matter for nutritious foods. The condition of alcohol fermentation was investigated by the addition of 2.5, 5.0, 7.5, 10.0, 12.5 and 15.0% dried lily scale and 10, 20, 30, 40 and 50% raw lily scale into mash, respectively. The maximum amount of ethanol was produced when 15% dried lily scale and 20% raw lily scale were added to cooked rice at $25^{\circ}C$ for 10 days. In overall acceptability of sensory evaluation, the LSD-5 alcoholic beverage (added 5% dried lily scale into mash) and LSR-20 alcoholic beverage (added 20% raw lily scale into mash) showed the best acceptability. Physiological functionalities of LSD-5 and LSR-20 alcoholic beverage were investigated. Electron donating ability by DPPH solution ($16.5{\sim}23.2%$), SOD-like activity ($20.4{\sim}24.7%$), ACE inhibitory activity ($24.7%{\sim}78.2%$) and tyrosinase inhibitory activity ($57.4{\sim}62.6%$) of LSD-5 and LSR-20 alcoholic beverage were better than the control (non-added liquor). Moreover, acceptability and physiological functionalities of LSD-5 alcoholic beverage are better than LSR-20.

• The Korean Journal of Mycology
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• v.40 no.4
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• pp.204-209
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• 2012

In this study, a novel yeast, Y111-5 for Makgeolli manufacture was selected from Nuruk yeasts, and its optimal culture condition were investigated. The Y111-5 strain was identified as Saccharomyces cerevisiae by phylogenetic analysis of 18S RNA sequence. The maximal growth was obtained when the yeast was cultivated at $30^{\circ}C$ for 15 h in the medium containing sucrose 9% and yeast extract 5%.

• 한국균학회소식:학술대회논문집
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• 2015.11a
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• pp.39-39
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• 2015

Korean traditional Nuruk has been developed with various materials and shapes according to geographical environments and climates of their origins. Nuruk is also known as kokja in Korea, reflecting the understanding that microorganisms such as wild fungi, yeasts, and lactobacillus bacteria are naturally inoculated and reproduced. The objective of this study is to identify the characteristics of traditional Nuruk through recreating traditional production methods detailed in ancient Korean documents. In the present study, a total of 58 different kinds of Korean traditional Nuruk were prepared, including 46 kinds of recreated products. Each Nuruk sample was evaluated for its enzymatic activities, including glucoamylase, protease, and glucanase. Their suitability for alcoholic beverage production were compared to each other. To isolate valuable microorganisms from Nuruk samples, alcoholic beverages produced using each sample were subjected to sensory evaluation to determine their taste. In addition, metabolite changes in traditional alcoholic beverages fermented with different kinds of Nuruk were analyzed through mass-based metabolomics approach. This study presents, for the first time, the traditional production methods written in ancient Korean documents using workable production methods supported by modern technologies. In addition, this study analyzed the characteristics of reproduced Nuruk. It could be utilized as a basis for studying traditional Korean traditional alcoholic beverages and their valuable microorganisms.

• Food Industry And Nutrition
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• v.6 no.3
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• pp.5-10
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• 2001