• 동아시아식생활학회지
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• 제25권6호
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• pp.1041-1048
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• 2015

This study was performed to produce quality vinegar using different types of nuruk, which is the most effective in making traditional brown rice vinegar. The vinegar was produced with 20% vinegar starter, and pears were added to reduce the nuruk aroma. Three different types of Nuruk that were prepared were rice, wheat, and a rice+wheat (1:1) combination. The total acidities of brown rice pear vinegar made from rice-nuruk, wheat-nunuk, and rice+wheat-nuruk were 8.1%, 7.5%, and 6.4%, respectively. Free sugars, including glucose, galactose, and fructose, were highly detected from all three vinegar samples. Acetic acid and lactic acid were the major organic acids in all three vinegar samples. For free amino acids, alanine, glutamic acid, and arginine were mainly detected in all three vinegar samples. Total phenolic compounds were higher in brown rice pear vinegar made of rice-nuruk than in that made of wheat-nuruk, whereas total flavonoids showed the opposite pattern. DPPH-radical scavenging activity was higher in brown rice pear vinegar made of wheat-nuruk than in that made of rice-nuruk.

• 동아시아식생활학회지
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• 제27권2호
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• pp.159-167
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• 2017

In this study, quality characteristics of yakju fermented with byeo-nuruk prepared using rice, wheat, and water were investigated. Five different mixture ratios were considered for byeo-nuruk preparation. A comparative analysis of commercial yakju and byeo-nuruk yakju was also performed. The results showed no significant differences in pH, total acidity, and total soluble solids of byeo-nuruk yakju immediately following fermentation. The byeo-nuruk yakju alcohol content increased with increasing wheat proportion. Lactic and succinic acid were the major organic acids of byeo-nuruk yakju, and the major volatile components were isoamyl alcohol and linalool. Yakju prepared using material D had the highest volatile component content and high preference evaluation scores for taste and overall acceptability. Compared to commercial yakju, byeo-nuruk yakju had less total acidity, soluble solids, and volatile acids, whereas its pH level and amino acid content were higher. No significant differences were observed between commercial yakju and byeo-nuruk yakju in terms of sensory evaluation.

• 동아시아식생활학회지
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• 제18권1호
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• pp.41-48
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• 2008

This study focused on the alcohol fermentability of traditional Nuruk, as well as yeast containing traditional Nuruk, in the production of Yakju. The fermentation performed with 30% Nuruk was effective with regard to alcohol yield. In addition, the fermentation containing 70% Nuruk showed the highest titratable acidity due to increased amounts of organic acids (succinic acid, oxalic acid, malic acid, acetic acid), which, however, negatively influenced the Yakju quality. Moreover, microbiological contamination always occurred in the fermentations using only Nuruk. In contrast, in the experiments with the yeast containing Nuruk, higher alcohol content and lower titrable acidity were obtained, independent of the Nuruk ratio used, positively effected the Yakju taste and flavor. Overall, the fermentation performed using the yeast containing 30% traditional Nuruk showed the best results for Yakju production.

• 한국산학기술학회논문지
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• 제20권2호
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• pp.535-542
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• 2019

본 연구는 각종 누룩으로 제조한 누룩소금들의 성분을 비교분석하여 누룩소금 제조시 필요한 기초자료를 확보하고 사용자의 요구에 맞는 누룩소금을 선택할 수 있도록 하는 것을 목적으로 하였다. 누룩종류로 이화국, 미인국, 백국, 입국을 선정하여 누룩을 제조한 후 특성을 파악하였고, 재료비율과 온도 등 동일한 발효조건하에 누룩소금을 제조 후 이화학적 특성을 분석하였다. 누룩소금 제조 시 pH는 발효전 6.2-6.5에서 발효 3일후 6.1-6.2로 떨어진 다음 이후에는 약간 높아졌다. 총산은 발효전 0.16-0.18에서 발효후 0.22-0.25로 증가하였으며 누룩 간 차이는 없었다. 당도는 발효 후 높아졌으며 입국으로 만든 누룩소금이 가장 큰 당도 증가를 보였다. 누룩소금의 염도는 발효 전 30-32에서 발효 후 37-44로 높아졌으며 입국의 증가폭이 가장 컸다. 누룩소금의 유기산은 acetic acid, oxalic acid, malic acid, lactic acid, citric acid 순으로 많이 검출되었다. 백국소금의 oxalic acid는 0.77 mg/mL으로 입국소금의 2.3배 많았고, succinic acid도 1.19 mg/mL로 백국소금이 가장 많은 것으로 나타났다. 한편 malic acid, lactic acid, acetic acid 및 citric acid는 각각 0.29 mg/mL, 1.48 mg/mL, 0.12 mg/mL로 입국소금이 가장 많은 것으로 나타나 입국으로 제조한 누룩소금이 다른 누룩으로 제조한 누룩소금 보다 부드러운 감칠맛이 더 좋은 것으로 나타났다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2015년도 추계학술대회 및 정기총회
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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.

• Journal of Biomedical and Translational Research
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• 제19권4호
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• pp.103-109
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• 2018

Aspergillus luchuensis 34-1 was inoculated into wheat pellets with different conditions of raw materials to produce nuruk. The degree of substrate reactivity improvement of steam treated raw materials compared with that of non-heat treated was analyzed. The water content of the pellet was adjusted to 25% and 35%, and steam treatment for 10 minutes improved the substrate reactivity at 2.1-fold and 3.1-fold, and sterilization was also possible. The characteristics of improvement pellet nuruk were investigated according to the degree of crushing and water content of raw materials according to the temperatures and humidities ($23^{\circ}C$, $30^{\circ}C$ and RH 60%, RH 80%). The pH of the pellet nuruk was higher depending on the temperature, humidity and moisture content of the koji were lower, and the pH of the flour-pellet nuruk was lower than that of 2 mm milling wheat-pellet nuruk according to milling degree. It can be seen that the milling degree affects the growth of mold. The acidity and amino acid were generally higher as fermentation time increased. Also, the higher the incubation temperature, humidity and moisture content, the higher the value. Glucoamylase activity was significantly the highest in moisture content 35% D2b nuruk, cultured at $30^{\circ}C$ and 80% RH for 38 hours. This is higher than the previous reports on glucoamylase of rice-koji or commercial nuruk using fungi isolated from traditional nuruk. From these study, it is expected that making of improvement pellet nuruk would save the fermentation time considerably compared with traditional nuruks.

• 한국미생물·생명공학회지
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• 제28권5호
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• pp.303-308
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• 2000

The character-istics of the volatile flavor components of traditional Korean Nuruk produced by Aspergillus oryze NR 3-6 and Penicillium expansum NR 7-7 were investigated. Volatile flavor of Nuruk was identified twenty-one components by gas chromatography-mass spectronmeter. Major flavor components were alkanes such as tridecan, tetradecan, penta-decane, hexadecane, heptadecane, octadecan, undecane, and dodecane.

• 동아시아식생활학회지
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• 제21권6호
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• pp.877-881
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• 2011

전통누룩에서 분리한 A. oryzae N041 균주를 서로 다른 4종류의 곡물에 접종하여 낱알누룩을 제조하였고, 이를 이용하여 빚은 막걸리의 품질특성을 조사하였다. 곡물별 낱알 누룩의 품질특성을 분석한 결과, 쌀 낱알누룩보다 녹두 낱알누룩에서 산도와 아미노산도, 당화력이 높게 나타났다. 제조한 곡물별로 막걸리를 빚어 양조적성을 분석한 결과, 녹두 낱알누룩이 타 곡물 낱알누룩보다 당도와 환원당 함량이 높았으며, 반면 알코올 함량은 낮게 나타났다. 술덧의 유기산은 citric acid, malic acid, succinic acid 등의 주요한 유기산이 확인되었으며, 전체 유기산의 총량은 쌀(1,748.5 mg%), 녹두(1,551.2 mg%), 보리(1,003.2 mg%), 율무(940.8 mg%) 순으로 유기산 생성량이 많았다. 특히, 녹두 낱알누룩으로 빚은 막걸리는 아미노산도와 유기산 함량이 높아 소비자가 마시기 쉬운 감칠맛과 녹두가 가지는 깊은 풍미를 가질 것으로 기대된다.

• 동아시아식생활학회지
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• 제22권1호
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• pp.103-108
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• 2012

밀, 쌀 및 녹두를 분쇄 후 밀기울을 첨가하여 일정 비율(15:1:1:3)로 혼합한 곡물에 양조용 곰팡이의 균종을 달리하여 제조한 누룩의 품질 특성을 알아보고자 발효 시기별 일반성분 및 효소활성과 유기산 분석을 하였다. 누룩의 pH는 발효 시기별 큰 차이는 보이지 않았으며, 산도와 아미노산도는 두균을 혼합하여 제조한 누룩(AO-AK)이 가장 높게 나타났다. 전반적으로 두 균을 혼합한 누룩이 단일 균을 접종한 누룩보다 ${\alpha}$-amylase 및 acidic protease의 효소활성이 높게 나타났다. 누룩의 유기산은 acetic, citric, formic, fumaric, lactic, malic 및 oxalic acid 등이 확인되었다. 전체 유기산 총량은 혼용누룩(2,116.3 mg%), A. kawachii SC60 단용누룩(1,608.5 mg%), A. oryzae RIB1353 단용누룩(1,146.7 mg%) 순으로 혼용누룩의 유기산 생성량이 가장 높게 나타났다. 따라서 두 균주를 혼용하여 제조한 누룩이 단일균주를 사용한 누룩보다 유기산 함량, 효소활성 등 품질 특성이 우수한 것으로 여겨진다.

• 한국식품영양과학회지
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• 제44권6호
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• pp.928-934
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• 2015

본 연구에서는 개량누룩을 정제효소로 대체하여 제조한 발효 술덧의 품질 특성을 알아보고, 정제효소의 대체가 누룩취 저감에 효과가 있는지를 검증하였다. 정제효소로의 대체량이 늘어날수록 발효 술덧의 특성은 부의 방향성을 보였다. 알코올 함량이 낮아 술의 생산 원가에 부정적인 영향을 미치는 것으로 나타났으며, pH가 높아져서 발효 시 유해미생물에 오염될 가능성이 높아질 것이라 보인다. 또한 가용성 고형분 함량도 높아서 개량누룩을 사용했을 때보다 발효가 늦게 진행되는 것이 발견되었다. 개량누룩의 사용량을 최대 30%까지 정제효소로 대체하였을 때 발효 술덧의 품질 변화에 유의미한 차이가 없었다. 정제효소($Sumizyme^{TM}$)로 30% 대체하여 제조된 발효 술덧 및 증류주는 누룩취의 강도에 있어서 개량누룩과 전통누룩으로 제조된 발효 술덧 및 증류주와 비교해서 통계적으로 낮은 누룩취 강도를 보여주었다. 누룩의 일부분을 정제효소로 대체함으로써 쌀 증류주의 누룩취를 저감할 수 있을 것이다.