• Journal of Microbiology and Biotechnology
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• v.23 no.5
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• pp.681-688
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• 2013

This work is aimed to increase knowledge of the functional exopolysaccharide (EPS) from lactic acid bacteria (LAB) in makgeolli, a Korean fermented rice wine. Among LAB strains isolated from makgeolli, strain M76 was selected as a functional strain producing a bioactive EPS, based on its antioxidative activity on the DPPH radical. The 16S rRNA gene sequencing analysis showed a high sequence similarity (99.0%) with P. acidilactici, but had different biochemical properties with the already known P. acidilactici type strains in the aspect of carbohydrates utilization. The obtained P. acidilactici M76 produced a soluble EPS above 2 g/l. One-step chromatography using gel filtration after ethanol precipitation from the supernatant of P. acidilactici M76 was enough to obtain purified EPS with a single peak, showing a molecular mass of approximately 67 kDa. Componential and structural analyses of EPS by TLC, HPLC, and FT-IR indicated that the EPS is a glucan, consisting of glucose units. The purified EPS had antioxidant activity on the DPPH radical of 45.8% at a concentration of 1 mg/ml. The purified EPS also showed proliferative effect on the pancreatic RIN-m5F cell line and remarkable protection activity on alloxan-induced cytotoxicity. This potent antioxidant and antidiabetic EPS by LAB in makgeolli may contribute to understanding the functionality of makgeolli.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1749-1757
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• 2012

Makgeolli is a traditional rice wine favored by the general public in Korea. This study investigated the fermentation and sensory characteristics of using wild yeast strains for brewing makgeolli. A non-Saccharomyces cerevisiae strain was isolated from nuruk and termed Y197-13. It showed 98% similarity to Pichia anomala and had an optimal growth temperature of $25^{\circ}C$. Makgeolli was manufactured using koji, jinju nuruk, and improved nuruk as fermentation agents. Y197-13 makgeolli brewed with koji had alcohol and solids contents of 11.1% and 13.9%, respectively. Sweet sensory characteristics were attributed to residual sugars in makgeolli with 6% alcohol. The makgeolli had a fresh sour taste and carbonated taste. Volatile component analysis showed the isoamyl alcohol, phenylethyl alcohol, isoamyl acetate, and fatty acid, including ethyl oleate and ethyl linoleate, relative peak area was higher in Y197-13 makgeolli than in makgeolli with Saccharomyces cerevisiae. These results suggest the wild yeast, Y197-13, as a candidate for brewing makgeolli.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1736-1743
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• 2017

Sourdough is made by fermentation of dough by lactic acid bacteria (LAB) and yeast to improve bread properties like volume, flavor, and texture. A Korean traditional sourdough was made by fermenting rice flour with rice wine (makgeolli) and used to make sponge-like bread (jeung-pyun). The aim of this study was to investigate the microbial diversity of makgeolli products and their influence on the organoleptic quality of jeung-pyun. Three commercial makgeolli were tested for jeung-pyun production, with each product exhibiting varied dough swelling rates and organoleptic qualities, and among them, J-product was ranked highest in texture and taste. Microbial analysis of the three makgeolli also showed a big difference in their population and diversity. J-product had the highest LAB and yeast counts, and the predominant species were Lactobacillus casei, Lactobacillus brevis, Leuconostoc pseudomenteroides, and Saccharomyces cerevisiae. Using J-product, sourdough was fermented at $25^{\circ}C$, $30^{\circ}C$, and $35^{\circ}C$, and the microbial growth in and textural properties of jeung-pyun were examined by instrumental and sensory tests. At high temperature ($35^{\circ}C$), the rates of dough swelling and acidification were fast due to rapid microbial growth mainly caused by LAB, resulting in a short leavening time and soft and sour jeung-pyun. Sensory tests showed consumer preference for the soft and mild-sour jeung-pyun. This study shows that LAB in makgeolli play key roles in production of jeung-pyun, influencing the textural and sensory properties. For the production of high-quality jeung-pyun, development of LAB starters with high gas productivity and low acidity and establishment of an optimal fermentation procedure for rice dough are necessary.

• 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 $25^{\circ}C$.

• Korean journal of food and cookery science
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• v.29 no.6
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• pp.777-784
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• 2013

With the development of economy and culture, Korean traditional rice wine, Makgeolli, has been widely consumed with increasing popularity in Korea, China and other Asian countries. In this study, we examined the quality characteristics of red bean Makgeolli: pH, total acidity, alcohol contents, sugar contents, reducing sugar, color, total flavonoid contents, DPPH, microbial properties, sensory evaluation of Makgeolli added with red bean (0, 5, 10 and 15% by rice weight) during fermentation for 7 days. There were no significant differences between samples in acidity, alcohol contents, reducing sugars and yeat cell counts, but total flavonoid contents increased with increasing ratio of red bean(p<0.05). Makgeolli added with 10% red bean showed the highest antioxidation activity, and was not significantly different with Makgeolli without red bean in flavor, sweetness, sourness, bitterness and overall acceptance in sensory evaluation. Therefore, Makgeolli added with 10% red bean was considered to be the most suitable for the manufacturing.

• KSBB Journal
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• v.27 no.4
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• pp.251-256
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• 2012

In this study we investigated the effect of temperature on the two-stage fermentation of Makgeolli using uncooked germinated black rice. The fermentation processes were conducted at $15^{\circ}C$ for three weeks and $25^{\circ}C$ for 7 days. The pH of Makgeolli at $25^{\circ}C$ increased from pH3.0 to pH 4.2, which was consistent with that at $15^{\circ}C$. In contrast total acidity of Makgeolli at $15^{\circ}C$ was about half of that at $25^{\circ}C$ (0.36% and 0.59%, respectively). By the 7 days-fermentation at $25^{\circ}C$, 11% of alcohol was produced, whereas three weeks were required for the same alcohol production at $15^{\circ}C$. In the case of sugar contents, the amounts of total glucose-equivalent reducing sugars and glucose increased at the end of the fermentation at $25^{\circ}C$ up to 2.25 mg/mL and 3.4 mM, respectively, whereas those at $15^{\circ}C$ were maintained at very low levels (0.18 mg/mL and 0.1 mM, respectively). Such limited supplement of sugars at $15^{\circ}C$ seemed to affect metabolism of yeast, resulting in different composition of organic acid. At $25^{\circ}C$, citric acid that was 73.4 ppm at the initial fermentation was consumed completely, whereas 20 ppm of citiric acid was remained at $15^{\circ}C$. In addition, acetic acid and lactic acid in Makgealli at $15^{\circ}C$ were 53% and 14% of those at $25^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.583-591
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• 2012

Four kinds of makgeolli brewed with different proportions of rice and wheat flour were prepared to investigate the effects of the carbohydrates source on the storage properties, and to examine the chemical characteristics and BA (biogenic amine) contents in makgeolli stored over 30 days at 4, 10 and $20^{\circ}C$, respectively. The chemical properties and BA contents were sustained at a consistent level for those makgeolli stored at $4^{\circ}C$ over 30 days. The alcohol content was significantly higher for makgeolli brewed with higher proportions of rice (R) over wheat flour (WF) (R 100: WF 0, R 70: WF 30) when compared with those brewed with a high proportion of wheat flour (R 30: WF 70, R 0: WF 100), and increased with increasing storage temperature and duration. The free amino acid contents of makgeolli brewed with high proportion of rice were significantly lower under the same conditions. Among the 8 BAs examined, tyramine, putrescine, cadaverine and phenylethylamine were detected, while tyramine and putrescine were mainly detected. Histamine was not detected throughout storage. Makgeolli brewed with rice as the only carbohydrate source exhibited very low levels of total BA during 30 days of storing at $20^{\circ}C$. Total BA contents of R100, R70, R30, R0 were 178.6, 682.9, 1186.7 and 1150.4 mg/L, respectively. These results suggest that makgeolli brewed with relatively higher proportions of rice have better storage properties and are safer for consumption.

• The Korean Journal of Food And Nutrition
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• v.26 no.4
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• pp.633-637
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• 2013

There is an increasing consumption of Makgeolli in both domestic and foreign markets due to a high interest in Korean traditional alcoholic beverages. However, currently, a standardized system of manufacturing, storing and circulating Makgeolli is not available. Therefore, manufacturing the constant quality of finished products is hardly achieved due to the uncertified quality index of Makqeolli. In particular, quality changes occur as a result of variable initial load of microorganisms during shelf life. Eight different commercially available brands of Makgeolli were obtained, and their initial concentrations of yeasts were measured. One brand with the highest concentration was chosen, and the variable initial concentrations were prepared at a concentration of $10^6{\sim}10^8$ yeast CFU/ml. These Makgeolli samples were heat-treated at 65, 70, 75 or $80^{\circ}C$. It was shown that temperatures higher than $75^{\circ}C$ were needed in order to pasteurize Makgeolli properly. In addition;it is considered that controlling the microorganisms by a standardized system for the processing analysis would improve the quality of Makgeolli.

• Journal of Biosystems Engineering
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• v.43 no.3
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• pp.229-236
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• 2018

Purpose: Makgeolli is a traditional alcoholic beverage made from rice with a fermentation starter called "nuruk." The concentration of alcohol in makgeolli depends on the temperature of the fermentation tank. It is important to monitor the alcohol concentration to manage the makgeolli production process. Methods: Data were collected from 84 makgeolli fermentation tanks over a year period. Independent variables included the temperatures of the tanks and the room where the tanks were located, as well as the quantity, acidity, and water concentration of the source. Software for the multilayer perceptron model (MLP) was written in Python using the Scikit-learn library. Results: Many models were created for which the optimization converged within 100 iterations, and their coefficients of determination $R^2$ were considerably high. The coefficient of determination $R^2$ of the best model with the training set and the test set were 0.94 and 0.93, respectively. The fact that the difference between them was very small indicated that the model was not overfitted. The maximum and minimum error was approximately 2% and the total MSE was 0.078%. Conclusions: The MLP model could help predict the alcohol concentration and to control the production process of makgeolli. In future research, the optimization of the production process will be studied based on the model.

• The Korean Journal of Mycology
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• v.39 no.2
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• pp.122-125
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• 2011

The goal of this study was to provide shelf-life of Gugija-Liriope tuber raw makgeolli. After we prepared Gugija-Liriope tuber raw makgeolli by using Gugija, Liriope tuber, nuruk, cooked rice and Saccharomyces cerevisiae C-2, changes of its quality and physiological functionality were investigated during the storage at $4^{\circ}C$ and $20^{\circ}C$. Ethanol contents was decreased from 8.3% to 7.2% for storage of 9 days at $4^{\circ}C$ and 6 days storage at $20^{\circ}C$, respectively. Antihypertensive angiotensin I-converting enzyme inhibitory activity of Gugija-Liriope tuber makgeolli was increased from 63.1% to 66.0% after storage for 9 days at $4^{\circ}C$. Total acceptability of 9 days storage makgeolli at $4^{\circ}C$ was still good. In conclusion, shelf-life of Gugija-Liriope tuber raw makgeolli was 9 days at $4^{\circ}C$ in this respect of ethanol contents, antihypertensive action and total acceptability.