• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.2
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• pp.301-307
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• 2010

This study evaluates quality of Nuruk, which is a source material of Takju, collected in Daegu and Gyeongbuk and investigates fermentation characteristics of Takju made of it. Totally 7 types of Nuruk were examined and their pH and titratable acidity were 5.4~5.9 and around 0.1%, respectively. Saccharifying activity was high in D, F, G, A and E Nuruk by recording over 300 mg%. Lactic acid bacteria count was the highest in G Nuruk with $3.78\times10^8$ and yeast and total microbe count recorded the highest levels, $3.78\times10^8$ and $3.47\times10^8$, respectively in B Nuruk. When quality characteristics of Takju made of each type of Nuruk were compared, alcohol content was the highest in G Nuruk by recording 19.0% and titratable acidity was 0.44~0.86% in all samples. Hunter's color, brown color and turbidity showed different levels according to types of Nuruk and all lactic acid bacteria, yeast and total microbe counts were the highest in A and E Nuruk. For alcohol components, E and G Nuruk showed high fusel oil content levels and methanol and fusel oil contents of all samples were suitable as standards, respectively. The total organic acid content was the highest in B Nuruk at about 4,000 mg% and it was 2,000 mg% and around 1,000 mg% in A, E, F and G Nuruk and C and D Nuruk, respectively. The content of total free amino acid was the highest in B Nuruk at 3,676 mg% and it was observed to be 1,890, 1,676 and 1,531 mg% in G, E and C Nuruk in that order, respectively. Sensory preference of subjects in their 20s was high overall in G and C Nuruk and that of those in their 40s was high in F and C Nuruk. From all of these results, the types of Nuruk largely affected quality and components of Takju and an appropriate method to consider useful purpose is needed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.4
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• pp.577-583
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• 2014

In this study, we evaluated fermentation characteristics of microorganism with antimicrobial activity in makgeolli made from various kinds of koji and nuruk during fermentation. The pH of nuruk groups decreased compared to the koji groups after 3 days of fermentation. Acidity and alcohol contents of nuruk groups significantly increased compared to the koji groups. The total sugar contents of the koji groups were significantly higher than those of the nuruk groups after 15 days of fermentation. Sensory scores of koji groups (DKB) were higher than those of other samples. Antimicrobial activities of nuruk group (GND and ANF) against Salmonella enterica, Bacillus subtilis, Escherichia coli, and Bacillus cereus were significantly higher compared to the koji group. ST-1, isolated from (Geumjeonggu nuruk D), showed the highest antimicrobial activity and was identified as Paenibacillus polymyxa strain RCP6 based on 16S rRNA sequencing. Our result suggest that Paenibacillus polymyxa from nuruk group produces a bacteriocin-like substrate with antimicrobial activity.

• Journal of Life Science
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• v.22 no.1
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• pp.110-116
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• 2012

Nuruk plays a significant role in the flavor and quality of Takju and Yakju, which are produced through saccharification and alcohol fermentation by various microorganisms. In this study, we identified microbial strains isolated from a plate count and PCR-denaturing gradient gel electrophoresis (DGGE) analysis targeting the 16S and 28S rRNA genes, in order to characterize bacterial and fungal diversity in Sansung Nuruk. The numbers of bacteria and fungi in Nuruk were $1.5{\times}10^9$ CFU/g and $2.2{\tims}10^8$ CFU/g, respectively. The 16S rRNA gene sequence indicated that the predominant bacteria in the isolates and PCR-DGGE profile of Nuruk were Kocuria spp., Pantoea spp., Lactobacillus spp., Pediococcus spp., Weissella spp., Staphylococcus spp., endophytic bacterium, uncultured Gamma-proteobacteria, uncultured Cyanobacteria, and Actinobacteria. Dominant bacteria from the PCR-DGGE profile were Pediococcous pentosaceus and uncultured Cyanobacteria. The 28S rRNA gene sequence indicated the predominant fungi in the isolates and PCR-DGGE profile to be Trichomonascus spp. Pichia spp., Torulaspora spp., Wickerhamomyces spp., Sacharomycopsis spp., Lichtheimia spp., Mucor spp., Rhizopus spp. Aspergillus spp., and Cladosporium spp. Dominant fungi from the PCR-DGGE profile were Pichia kudriavzevii and Aspergillus oryzae. The PCR-DGGE technique was used for the first time in this study to assess a microbial community in Nuruk and proved to be an effective protocol for profiling microbial diversity.

• Korean Journal of Food Science and Technology
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• v.52 no.1
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• pp.94-102
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• 2020

Brown rice Makgeolli was brewed by using the Saccharomyces cerevisiae strain SRCM102596 under different fermentation conditions: temperatures at 20 and 25℃ and Nuruk ratios of 5, 10, and 15%. There were no significant differences in the pH and total acidity between samples. The alcohol content at the different nuruk ratios varied significantly by the days in the fermentation process. The major free sugars were maltose, glucose, and fructose, and they gradually reduced with fermentation. The major organic acids in the brown rice Makgeolli were oxalic acid, citric acid, malic acid, succinic acid, and acetic acid. The lactic acid content increased with the number of days in the fermentation process. Among the 24 different free amino acid contents identified, the total free amino acid content of, especially, threonine, serine, and alanine were high in the brown rice Makgeolli, at 20℃ and nuruk ratio of 10%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.505-511
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• 2013

To investigate the potential use of makgeolli by-products as cosmetic materials, their phenolic and kojic acid contents, antioxidant activity, whitening effect, and anti-wrinkle activity were evaluated. Extracts were obtained with five different solvents (containing 0, 25, 50, 75, and 100% ethanol) from nuruk lees (NL), rice lees (RL), raw makgeolli (RM), and commercial makgeolli (CM) at 20 and $50^{\circ}C$. NL and CM extracts prepared with 75% ethanol had the highest phenolic contents (13.26 and 16.66 mg gallic acid equivalents/g, respectively) at 20 and $50^{\circ}C$, respectively. The highest kojic acid content was found in NL extracts with 0% ethanol at $20^{\circ}C$, while kojic acid was not detected in extracts prepared at $50^{\circ}C$. NL and RL extracts at $20^{\circ}C$ showed significant antioxidant activity. Whitening effects, determined by tyrosinase inhibitory activity, were highest for the NL extract prepared with 75% ethanol at $50^{\circ}C$. Noticeable anti-wrinkling effects, estimated by elastase inhibition activity, were also found in NL and RL extracts. These results suggest that makgeolli by-products could be valuable cosmetic materials with antioxidant, whitening, and anti-wrinkle activities.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.943-950
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• 2003

To identify the functional properties of Hongkuk ju and to improve its brewing process, Hongkuk ju was brewed using different hongkuks (Monascus red koji) made by Monascus purpureus, Monascus anka, Monascus aruneosus, and nuruk. Hongkuk using M. purpureus showed the highest enzyme activity. Hongkuk ju prepared with the M. purpureus hongkuk was fermented most efficiently, and showed the highest Hunter value. Hongkuk ju showed significant levels of phenolic compounds, electron donating ability, nitrate-scavenging activity, and ACE inhibition activity. In particular, Hongkuk ju made with M. purpureus showed the highest value among the wines of this study.

• Food Science and Preservation
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• v.24 no.5
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• pp.714-724
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• 2017

Soju is a Korean traditional distilled alcoholic beverage produced from mashes various crops and Nuruk which is cultured with wild microorganisms. This study was conducted to investigate rice-Soju brewing characteristics of yeasts isolated from Korean traditional Nuruk. The general components of rice (Hanarumbyeo) raw materials were 14.7 g of water, 6.8 g of crude protein, 0.9 g of crude lipid, 0.4 g of crude ash, and 76.5 g of carbohydrate in 100 g. Saccharifying and proteolytic activities in Hanarumbyeo ipguk (solid-state culture of Aspergillus luchuensis) were also determined. The alcohol content of the fermented wash from isolates was 15.37-16.58% (v/v), which is 16.7-36.0% higher than that of industrial yeasts (12.33-13.19%). Reducing sugar contents were 2.04-3.92 and 7.92-8.78 g/100 mL in the isolates and industrial yeasts, respectively. The isolated yeasts showed 25.2-52.7% higher yield of distillates (41% alcohol) compared to industrial yeasts. Forty-one components were detected in the rice distillated Soju (25% alcohol) and principal component analysis revealed differences between the isolated and industrial yeasts with respect to the contents of i-BuOH, isobutanal diethyl acetal, ethyl caprate, and tetradecanoic acid.

• Microbiology and Biotechnology Letters
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• v.28 no.5
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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.

• 월간낙농육우
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• v.21 no.4 s.228
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• pp.166-169
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• 2001

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2001.12a
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• pp.122-122
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• 2001

쌀과 같은 곡류는 전분질을 당분으로 전환시켜 술을 제조하여야 하므로 미생물이 생성하는 효소가 필요한데 그 효소원이 누룩이며 누룩은 주류의 품질이나 생산량에 영향을 미치는 가장 중요한 요소라고 할 수 있다. 본 연구는 전국44개 지역의 누룩에서 순수 분리된 89종의 곰팡이 중 효소역가와 당화력이 비교적 뛰어난 10종(Aspergillus sp. SH-412 Heunghae, Aspergillus sp. SH-422 Ulsan, Rhizopis sp. SH-606 Imdeok, Aspergillus sp. SH-607 Yhesan, Aspergilus sp. SH-613 Wolseong, Rhizopus sp. SH-654 Uncheon, Aspergillus sp. SH-660 Jeonkok, Aspergillus sp. SH-667 Dongseong, Aspergillus sp. SH-669 Uncheon, Aspergillus sp. SH-696 Daecheon)과 대조균주로 Aspergillus kawachii CF1002 그리고 효모 Saccharomyces cerevisiae를 사용하셨으며 탁주제조 중 균주별 술덧의 산도, 환원당, 아미노산도와 제조된 완성주의 유기산, 유리아미노산, 유리당, 휴젤유 및 색도를 HPLC, GC Mass, 색차계로 측정한 결과 다음과 같은 결론을 얻었다. 균주별 술덧의 주정도는 모든 실험구에서 Aspergillus kawachii보다 높았으며 특히 Aspergillus sp. SH-422는 14.9%로 가장 수율이 좋았다. 환원당은 Aspergillus sp. SH-613이 0.49%로 가장 높았고 Aspergillus sp. SH-422는 0.37%로 가장 낮았으며 산도는 시간의 경과에 따라 감소했으며 술덧 발효중 아미노산도는 시간의 경과에 따라 약간 상승 후 다소 낮아지는 경향을 보였다. 각 균주별 술덧의 유기산은 tataric acid, malic acid, succinic acid, lactic acid, acetic acid가 검출되었으며 lactic acid 함량이 2.0∼3.2g/100ml로 가장 많이 검출되었다. 유기산은 Aspergillus sp. SH-669가 가장 높게 확인되었으며 Aspergillus sp. SH-607이 가장 낮게 분석되었다. 술덧의 주 아미노산은 histidine, alanine, glutamic acid, leucine, tryptophan순으로 검출되었으며 특히 alanine은 주류에 단맛을 주는 성분으로 모든 실험구에서 많은 양이 검출되었다. 각 균주별 술덧의 유리당은 glucose가 가장 많이 검출되었으며 Fusel oil은 iso-butyl alcohol과 iso-pentyl alcohol 이 가장 많이 검출되었다. 한편 균주별 술덧의 색차를 측정한 결과 L값은 63.33∼41.98, a값은 0.09∼-3.47, b값은 17.41∼4.90으로 나타났다.