• 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.

• The Korean Journal of Food And Nutrition
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• v.30 no.4
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• pp.719-727
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• 2017

The objective of this study was to investigate the effect of alcohol content in Makgeolli made with Chinese matrimony vine (M-CMV) on the sensory profile and consumer acceptability. The M-CMVs were prepared with 6, 7, 8, and 9% alcohol content. Descriptive analysis of M-CMV was performed with six trained panelists. Thirteen attributes were generated and their intensities were alcohol content dependent. The consumer acceptance test was conducted with 57 consumers. M-CMV samples with 7% alcohol had the highest acceptance rate (5.8) followed by 6% M-CMV (5.6). Commercial rice Makgeolli (CRM) had the lowest consumer acceptance. Consumers were divided into two groups by clustering analysis. The majority of consumers (n=38) preferred M-CMV and did not like the commercial sample. Only 19 consumers indicated high acceptance ratings for CRM. However, these consumers also preferred 6 and 7% M-CMV. Partial least-squares regression analysis revealed moderate attribute intensities were related to greater consumer acceptability. The optimal alcohol content for the greatest consumer acceptance predicted by linear regression was 6.7%.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.727-734
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• 2013

Makgeolli mashes that were brewed using five different commercial nuruks (fermentation starters) were investigated for changes in physicochemistry, microbial diversity, and biogenic amine (BA) production. Mash A brewed with the nuruk (Gaeryang-nuruk) had the highest level of alcohol concentration and the greatest number of yeast cells, whereas mash E had the greatest number of bacterial cells. Only three biogenic amines were detected in the makgeolli mashes: tyramine, putrescine, and cadaverine. Using a PCR-DGGE technique, we observed that mash E had the highest BA production, and had the greatest number of bands on the denaturing gradient gels. We also observed that the numbers of bacterial cells correlated significantly with the putrescine and the total BA content, and that the BA content correlated significantly with the color values (L, a, b). This study shows that the quality of a makgeolli can depend on the type of nuruk. Therefore, we suggest that the quality management of makgeolli should start with the stage of nuruk manufacture.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.573-578
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• 2015

This study was performed to elucidate the fermentation and sensory characteristics of Korean traditional rice wine, makgeolli, made from GABA rice, which has a high content of GABA (gamma-aminobutyric acid). GABA rice is a brown rice that is not easily fermented by general makgeolli manufacturing methods. Thus, the Geupchungju method, which is a Korean traditional manufacturing method for makgeolli using a fermentation starter and additional malt, was considered for making makgeolli from GABA rice. We confirmed that Geupchungju method showed a high saccharification and stable alcohol fermentation ability in the early stages of fermentation. However, malt addition more than 2% resulted in a lower score in the sensory evaluation of the final product. It was also confirmed that GABA content of GABA makgeolli was higher than that of commercial makgeolli by 2.3-fold. Our result provides useful information toward improving quality of brown rice makgeolli.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.226-233
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• 2017

Jeung-pyun, a fermented rice cake, is prepared by fermenting rice sourdough using makgeolli, a traditional Korean rice wine, in the presence of yeast and lactic acid bacteria (LAB). The goal of this study was to conduct biochemical and microbial analyses of five different rice sourdoughs, each fermented with a different commercial makgeolli, using culture-dependent and culture-independent approaches. All sourdough samples fermented with different makgeolli for 6.5 h showed different profiles in pH, total titratable acidity, organic acid concentration, and microbial growth. LAB belonging to different genera were identified based on colony morphology on modified MRS and sourdough bacteria agar medium. PCR-denaturing gradient gel electrophoresis analyses of the five sourdoughs showed different bands corresponding to LAB and yeast. 16S/26S rRNA gene sequence analyses of the samples confirmed that the predominant LAB in the five fermented rice doughs was Lactobacillus plantarum, Lb. pentosus, and Lb. brevis. Various other Lactobacillus spp. and Saccharomyces cerevisiae were common in all five fermented samples. This study provides comprehensive and comparative information on the microflora involved in fermentation of rice sourdough and signifies the need to develop effective starters to enrich the quality of jeung-pyun.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.367-376
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• 2014

This study's purpose was to investigate the characteristics of a traditional Korean rice wine containing lactic acid bacteria (LAB), called makgeolli. The makgeolli was brewed with the alcohol-tolerant Pediococcus acidilactici strain K3, and was analyzed for LAB cell counts, alcoholic content, turbidity, pH, total acidity, amino nitrogen, total sugars, reducing sugars, solid contents, and organic acids. The physicochemical properties of the makgeolli were mostly maintained during fermentation (9 d) and storage (15 d). We also monitored the properties of LAB-supplemented commercial makgeollies, after adding P. acidilactici K3 at a concentration of $10^7CFU/ml$ makgeolli, for one month. Most of their properties, such as alcoholic content, turbidity, pH, total acidity, amino nitrogen, total sugars, reducing sugars, solid contents, and organic acids, were preserved during storage at $10^{\circ}C$, suggesting that makgeolli supplemented with live LAB can be produced. These results suggest that alcohol-tolerant P. acidilactici K3 can be used for makgeolli brewing either as a starter or as a supplement.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.44-50
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• 2015

The purpose of this study was to characterize the lactic acid bacteria found in makgeolli in terms of bacterial identity and gastric compatibility. Lactic acid bacteria were isolated from commercial raw makgeolli and separated into six strains that are resistant to gastric acidity and bile acid. These strains were identified by analysis of their 16S rDNA, as Lactobacillus plantarum BSM-2 and EHJ-1, Lactobacillus casei GSM-3 and EHJ-2, Lactobacillus brevis BSM-3 and Pediococcus pentosaceus TJH-1. All strains exhibited adhesion to intestines, showing that they were probiotic. We also found that L. plantarum BSM-2 had excellent resistance to bile acid as well as antioxidant activity. Taken together with its antibacterial properties and ability to lower cholesterol, our data suggest that L. plantarum BSM-2 was the most beneficial probiotic among the six strains.

• Journal of the Korean Society of Food Culture
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• v.27 no.4
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• pp.383-390
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• 2012

This study was conducted to investigate the physicochemical and sensory changes of 6 kinds of commercial Makgeolli (A, B, C, D, E, and F) during storage at $4{\pm}1^{\circ}C$ for 30 days. The initial pH was 3.50~4.23, but it increased to 3.65~4.37 by the end of the storage period (p<0.05) There were no significant differences in titratable acidity between the beginning and end of the storage period. The reducing sugar content of A and B increased, whereas C, D, E, and F decreased with increasing storage time. A decrease in lightness (L values) was observed in all samples with increasing storage time (p<0.05). The alcohol content increased from beginning values of 5.90~6.10% to ending values of 6.30~7.35% at the end of storage, of which sample B exhibited the highest value. A sensory evaluation test revealed that the overall acceptability of samples A, B, D, and E were still within acceptable limits, but samples C and F showed undesirable changes during 30 days of storage at $4^{\circ}C$.

• The Korean Journal of Community Living Science
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• v.23 no.2
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• pp.199-206
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• 2012

In order to evaluate the aroma compounds in Korean traditional alcoholic beverages, volatile compounds of the commercial wines, Makgeolli were analyzed and quantified using the conventional method. Eight volatile compounds including three kinds of alcohols, two kinds of organic acids and three kinds of ether were extracted by Liquid-Liquid Extraction with Dichloromethane. For the separation and quantification, Gas chromatography coupled with mass spectrometry (GC/MS) was used to analyze these compounds. Also, the separation efficiency of these compounds was performed and compared with GC column. The results of this study were as follows ; Eight kinds of volatile compounds were separated well on the HP-88 column better than on the DB-5MS column. Short chain fatty acids, butyric acid and isovaleric acid were not detected in two brands of makgeolli samples. The higher alcohols were detected in the range of 0.86~225.68 ${\mu}g/mL$ and ethyl esters were detected in the range of 0.86~225.68 ${\mu}g/mL$, respectively. There compounds are known to be associated with sensory and odorant.

• The Korean Journal of Mycology
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• v.41 no.3
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• pp.167-171
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• 2013

The goal of this study was to screen a useful alcohol fermentative yeast for Gugija leaf makgeolli (Gl makgeolli) brewing and establish its optimal fermentation condition. Gugija leaves with various alcohol fermentative yeasts were added into the mixture of cooked non-glutinous rice and koji, and then fermented at $25^{\circ}C$ for 7 days. Among several Gl makgeolli, ethanol contents was the highest in Gl makgeolli made by S. cerevisiae F-1. Therefore, we selected S. cerevisiae F-1 as suitable yeast for brewing of Gl makgeolli. Gl makgelli with the best total acceptability and high antihypertensive action was obtained when cooked non-glutinous rice (120 g), boiled D.W (100 mL) and JJ koji (60.5 g/300 sp) were mixed and fermented for 2 days at $30^{\circ}C$ with S. cerevisiae F-1 (5%), and added again cooked non-glutinous rice (150 g), glutinous rice (100 g), D.W (500 mL) and Gugija leave (0.1%/cooked rice) and further fermented for 5 days at $25^{\circ}C$.