• Journal of Microbiology and Biotechnology
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• 제23권5호
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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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• 제22권12호
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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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• 제27권10호
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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.

• 한국균학회지
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• 제41권3호
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• pp.167-171
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• 2013

구기자 잎의 이용 범위 확대를 통한 폐기처리 비용 경감과 구기자 잎 약리효능의 부가적 이용 등을 목적으로 구기자 잎의 첨가가 전통 막걸리의 품질과 항고혈압활성에 미치는 영향을 조사하였다. 먼저 구기자 잎 막걸리 제조용 최적 효모를 선발한 결과, 우수 알코올 발효 효모로 시판 Saccharomyces cerevisiae F-1을 최종 선발하였다. 최적 알코올 발효조건을 검토한 결과 먼저 증자 멥쌀 120 g을 끓는물 100 mL로 호화시킨 후 시판 JJ곡자(300 sp) 60.5 g과 위에서 선발한 Saccharomyces cerevisiae F-1 활성액 5%를 첨가하여 $30^{\circ}C$에서 2일간 발효시켜 밑술을 제조하였다. 여기에 다시 증자 멥쌀 150 g과 찹쌀 100 g, 담금용수 500 mL을 혼합한 다음 구기자 잎을 증자미의 0.1%를 첨가하여 $25^{\circ}C$에서 5일간 발효시켜 여과했을 때 기호도가 우수하면서 항고혈압성 안지오텐신 전환효소 활성이 55.4%로 비교적 높은 구기자 잎 막걸리를 제조할 수 있었다.

• 한국식품조리과학회지
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• 제29권6호
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• pp.777-784
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• 2013

건조 쌀 중량 기준으로 팥 5%, 10%, 15%를 첨가하여 팥 막걸리를 제조하였고 이들의 품질특성과 기호도를 조사하였다. 그 결과, 막걸리의 품질을 평가하는 항목인 산도, 알코올 함량, 환원당, 효모계수에서 대조군을 포함한 모든 실험구에서 유의적 차이가 나타나지 않은 반면, 플라보노이드 함량은 팥 첨가 함량이 증가할수록 유의적으로 증가하였고(p<0.05) 항산화 활성(DPPH)은 팥 10% 첨가구가 가장 높게 나타났다. 또한 관능평가 결과, 팥 10% 첨가구는 향미(Flavor), 단맛(Sweetness), 신맛(Sourness), 쓴맛(Bitterness)과 전체적인 기호도(Overall acceptance)에서 대조군과 유의적인 차이가 없었고(p<0.05) 대조군과 같이 높은 점수를 받았다. 이러한 결과로 보아 막걸리의 항산화 활성이 가장 높으며 관능평가 결과에서 높은 점수를 받은 팥 10%를 첨가하여 제조한 막걸리가 가장 적합하다고 판단된다. 플라보노이드 등 기능성 물질을 다량 함유하고 있는 팥을 첨가하여 막걸리를 제조함으로서 막걸리의 기능성과 관능적인 측면을 향상시켜 전통주 시장에서의 경쟁력을 가질 수 있을 것으로 기대된다.

• KSBB Journal
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• 제27권4호
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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 $25^{\circ}C$.

• 한국식품과학회지
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• 제44권5호
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• pp.583-591
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• 2012

본 연구는 막걸리의 전분질 원료가 막걸리의 화학적 특성 및 BA 생성에 미치는 영향을 살펴보고자 하였다. 이를 위해 쌀과 밀가루 배합비율을 달리하여 제조한 4종류의 막걸리를 4, 10와 $20^{\circ}C$에 각각 30일간 저장하면서 알코올 함량, pH, 산도, 아미노산 함량과 함께 8종의 BA 생성 특성을 측정하였다. 막걸리의 알코올 함량은 저장기간이 경과하고 저장온도가 증가함에 따라 증가하였다. 또한 쌀만으로 제조한 막걸리 R100과 쌀 70%와 밀가루 30%로 제조한 R70의 알코올 함량이 밀가루 70%와 쌀 30%로 만든 막걸리 R30과 밀가루만으로 제조한 R0에 비해 많았다. 막걸리의 pH는 $4^{\circ}C$에서는 저장 30일까지 별다른 변화를 보이지 않았으나 저장온도가 증가할수록 낮아져서 초기에 pH 4.33-4.38이었던 것이 $10^{\circ}C$와 $20^{\circ}C$에서 30일째 저장한 경우 각각 pH 3.54-3.81, pH 3.30-3.43까지 감소하였다. 산도는 pH와 같은 경향을 보였으며, pH의 감소와 함께 산도는 증가하였다. BA의 전구체가되는 유리 아미노산의 함량 역시 저장기간이 경과할수록 그리고 저장온도가 증가할수록 증가하였다. 막걸리에서 측정한 8종의 BA 중 tyramine, putrescine, cadaverine과 phenylethylamine의 4종이 검출되었고, 이 중 가장 주된 BA는 putrescine과 tyramine이었다. BA 생성량은 막걸리의 종류와 저장온도 및 저장기간에 따라 현저한 차이를 나타내었다. 저장온도가 증가함에 따라 각각의 BA 함량이 크게 증가하였고, $4^{\circ}C$와 $10^{\circ}C$에서는 tyramine, putrescine, cadaverine만 검출된 것과 달리 $20^{\circ}C$에서는 미량이지만 phenylethylamine도 검출되었다. 그러나 전 기간을 걸쳐 histamine은 검출되지 않았다. 쌀과 밀가루 배합비율을 달리한 막걸리에 있어서 BA 생성량은 매우 큰 차이를 나타내었다. 총 BA의 최고 생성량은 R100과 R70이 각각 178.6와 682.9 mg/L를 나타낸 반면 R30과 R0는 각각 1186.7와 1150.4 mg/L를 나타내어 쌀의 배합비율이 높을수록 각각의 BA 뿐만 아니라 총 BA의 함량 역시 유의적으로 감소함을 알 수 있었다. 또한 막걸리의 화학적 특성과 BA 함량의 상관관계를 분석한 결과 pH의 변화 및 유리 아미노산 함량은 막걸리의 BA 생성과 유의적인 상관관계를 갖고 있음을 알 수 있었다. 이상의 결과로부터 막걸리는 시판 후 유통 기간 중에도 알코올 함량을 비롯한 화학적 품질 특성이 변화하고, BA 함량이 증가할 수 있으며, 이러한 변화는 저장 온도에 따라 크게 달라진다는 것을 알 수 있었다. 따라서 품질 변화를 늦추기 위해서는 막걸리를 저온 저장해야 하며, $10^{\circ}C$보다는 $4^{\circ}C$에서의 저장이 권장된다. 또한 쌀의 배합비율이 높은 막걸리는 밀가루 비율이 높은 막걸리에 비해 알코올 생성량은 많으면서도 BA 생성량은 유의적으로 낮아서 막걸리의 품질 특성뿐만 아니라 안전성 측면에서도 우수하다는 사실을 시사하였다. 이러한 연구결과가 막걸리를 쌀로 제조하여 저온저장 함으로써 막걸리의 짧은 유통기한을 연장하고, 전량 수입에 의존하는 막걸리용 밀가루를 국내산 잉여 쌀로 대체하게 함으로써 막걸리의 품질을 향상시키고 쌀 재고량을 감소시키는 데 도움이 될 수 있기를 기대한다.

• 한국식품영양학회지
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• 제26권4호
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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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• 제43권3호
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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.

• 한국균학회지
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• 제39권2호
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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.