• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.1
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• pp.157-162
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• 1996

A. oryzas 의 밀가루 누룩과 R. japonicus의 밀가루 누룩으로 탁주를 제조할 때에는 두 누룩의 혼합 비율이 탁주의 품질에 미치는 영향을 알아조기 위하여 두 누룩의 혼합 비율을 달리하여 7종의 탁주시료를 제조하고, 탁주의 이화학적 및 관능적 특성들을 조사하였다. R. japonicus는 누룩의 사용 비율이 높을 때에는 술덧의 산도와 유리당 함량이 높았고, 제성주의 부유물 함량과 부유물의 현탁 안정성도 높았다. 그러나 A. oryzas 누룩의 사용 비율이 높을 때에는 술덧의 산도와 유리당 함량이 낮았고, 제성주의 부유물 함량과 부유물의 현탁 안정성도 낮았다. R. japonicus 누룩과 A. oryzas 누룩을 2 : 1~5 : 1의 비율로 병용했을때에는 주박의 양이 크게 줄어들었고, 아미노산 함량이 증가하였으며, 기호성도 더 좋아졌다. 탁주의 전반적이 특성으로 볼 때 각 누룩의 단용시에는 R. japonicus 누룩이 A. oryzas 누룩보다 좋았다. 그러나 R. japonicus 누룩과 A. oryzas 누룩을 병용했을때에는 탁주의 전반적인 품질이 더욱 개선되어졌는데, 이때 두 누룩의 최적 혼합 비율은 대략 5 : 1이었다.

• 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.

• Food Science and Preservation
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• v.21 no.4
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• pp.573-580
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• 2014

The enzymatic activity of Nuruk and the quality properties of Yakju were investigated according to different fungi. The fungi that were used in this study were Aspergillus kawachii KCCM 32819, Aspergillus niger KCCM 32005, Rhizopus japonicus KCCM 11604, Rhizopus oryzae KCCM 11272, Rhizopus oryzae KCCM 11273, Rhizopus oryzae KCCM 11276, and Mucor rouxii KCCM 60148. The study results are as follows. The saccharogenic power of Rhizopus oryzae KCCM 11272 Nuruk was the highest (3,647.72 SP/g) among all the samples. The ${\alpha}$-amylase production and protease activities were highest (3.76 DU and 4.7 tyrosine mg/min, respectively) in the Rhizopus japonicus KCCM 11604 Nuruk. The pH levels of the Yakju made with commercial Nuruk and Rhizopus japonicus KCCM 11604 Nuruk were 4.14 and 4.07, respectively. The total titratable acid content of the Yakju made with Rhizopus oryzae KCCM 11273 Nuruk was the highest (0.56%) among all the samples. Rhizopus japonicus KCCM 11604 and Rhizopus oryzae KCCM 11272 had the highest ethanol yields (15.18% and 15.10%, respectively). In the sensory evaluation carried out in this study, the panel preferred the Yakju made with Rhizopus japonicus KCCM 11604 Nuruk. Overall, however, the panel did not like the Yakju made with Aspergillus niger KCCM 32005 Nuruk.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.1
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• pp.170-179
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• 1996

누룩은 생소맥을 조분쇄하여 물로 혼합시켜 자연적으로 공지중의 여러 종류의 미생물을 배양시켜 만들었다. 그러므로 누룩에서는 많은 종류의 사상균, 호모와 세균이 증식하였다. 누룩의 당화력은 원료 생소맥의 당화력과 대부분의 사상균의 당화력과 알붕의 세균성 당화력에 기인하여, 발효력은 누룩효모와 극소수의 사상균애 의하여 이루어지고 있다. 1945년 이전까지 누룩으로부터 12속 59종의 사상균이, 8속 29종의 효모와 4속 16종의 세균이 분리 되었다. 누룩사상균은 Aspergillus 속이 주종을 이루었고 Rhizopus속, Absidia속, Nucor속의 순으로 분포하고 있었고, Aspergillus속과 Rhizopus속은 중요한 누룩 당화균으로 작용하였다. 누룩의 대표적 효모는 Saccharomyces cerevisiae 이며 , 이균이 알코올 발효에 가장 큰 역할을 담당하며, Saccharomyces cerevisiae도 전통 민속주의 탁주와 약주의 발효역에 깊이관여한다고 사료된다. 누룩 중에 증식하는 세균은 양조학상 특별한 역할을 담당하지않지만 Bacillus 속 과 젖산세균이 많이 분리되었으며, 젖산세균은 담금초기에 pH의 안정화에 기여할 수 있다고 추측할 수 있다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.535-542
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• 2019

The purpose of this study was to obtain basic data necessary for making a nuruk salt by comparing and analyzing the ingredients of various nuruk salts, and to select a nuruk salt that meets the users' needs. We selected the types of nuruk as the ihwaguk, miinguk, baekguk, and koji to identify the characteristics of the nuruk, and then analyzed the chemical characteristics after manufacturing the nuruk salts under the same conditions of fermentation, such as material ratio and temperature. In the manufacture of nuruk salt, the pH level dropped from 6.2~6.5 before fermentation to 6.1~6.2 three days after fermentation. The Acidity increased from 0.16~0.18 before fermentation to 0.22~0.25 after fermentation and there was no difference between the nuruk. The sugar content has risen since fermentation, and nuruk salt made by koji showed the largest increase in the sugar content. The salinity of the nuruk salt was raised to 37~44 after fermentation from 30~32 before fermentation and indicated largest increase in nuruk salt made by koji. Organic acids of nuruk salt were detected in the order of acetic acid, oxalic acid, malic acid, lactic acid, and citric acid. The oxalic acid of the baekguk salt was found to be 0.77 mg/mL, 2.3 times more of the koji, and the succinic acid was also found to be the highest with 1.19 mg/mL. Malic acid, lactic acid, acetic acid, and citric acid were found to have the highest amount of koji salt at 0.29 mg/mL, 1.48 mg/mL, and 0.12mg/mL, respectively, making it a better taste to be soft than other nuruk salt.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5150-5158
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• 2014

This study examined the physicochemical characteristics of mashing prepared using different Nuruks (traditional Nuruk, Nuruk added Aspergillus oryzae, Nuruk added Aspergillus kawachii, and Nuruk added Aspergillus oryzae and Aspergillus kawachii), and to obtain the basic data for Korean Cheongju production. The four different mashes were compared for their brewing characteristics and indicated a normal fermentation pattern. The Nuruk made from A. oryzae or A. kawachii showed higher fermentation ability than the other samples tested. In addition, the analyzed results of fermented mashing showed that the Nuruk made from A. oryzae or A. kawachii had a significantly higher aroma profile, such as higher alcohol and ester than the other samples tested, whereas the Nuruk made from a mixture of A. oryzae and A. kawachii had a much higher organic acid content. In conclusion, the Nuruk prepared using A. oryzae or A. kawachii had a positive effect on the complete fermentation and enhanced aroma compounds for Korean Cheongju production.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.231-237
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• 2007

To support the fermentational superiority of Korean nuruks and maintain the various domestic nuruks, the optimal nuruk production of Andong-Soju, which was designated as an intangible cultural asset of Gyungsangbukdo province from 1987, was investigated. Different thickness of nuruks ($2.2{\sim}5.5\;cm$) were manufactured based on traditional Andong-Soju nuruk method, while the size of round form of nuruk was set to 23 cm. During the 3 weeks maturation, changes of water content, weight, pH, brix, the amount of reducing sugar, sac-charifying activity, viable cell and major microorganisms were determined, Also, ethanol fermentation abilities of the manufactured nuruks were evaluated using 20% glucose medium or 16% starch medium, respectively. Our results indicated that the production of high quality of Andong-Soju nuruk needs $4.0{\sim}5.5\;cm$ thickness and 3 weeks maturation without extraneous yeast addition. These results would be applied to production of homogeneous, and high quality of Andong-Soju nuruk.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.12
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• pp.2042-2048
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• 2013

This research was carried out to compare the physicochemical characteristics of Korean traditional spirits brewed with Phellinus linteus by different Nuruks. The spirits were produced by atmospheric distillation of rice mash added with 1~5% P. linteus and fermented by traditional and improved Nuruks. Traditional Nuruk facilitated more alcohol production than improved Nuruk during the initial fermentation time. The alcohol contents of rice mash with P. linteus ranged from 15.8 to 18.9%. Predominant volatile compounds were i-amyl alcohol of fusel oils and ethyl acetate of ester compounds in P. linteus added spirits. The spirits prepared by traditional Nuruk showed higher contents of i-butanol, n-butanol, and i-amyl alcohol than those by improved Nuruk. More ethyl acetate was produced in the spirits prepared by improved Nuruk than those by traditional Nuruk. The contents of methyl alcohol were less than 50 mg/L in P. linteus added spirits.

• Korean Journal of Food Science and Technology
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• v.48 no.3
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• pp.223-230
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• 2016

We investigated the fermentation characteristics of yakju made with nuruk extracts. Alcoholic fermentation was performed in an incubator set at $25^{\circ}C$ for 14 days. The study results are as follows: the alcohol content of yakju made with modified nuruk (18.67%) was higher than that made with other nuruk extracts (14.80-17.50%). The pH value of this modified nuruk (4.13) was higher than that of traditional nuruk (3.70-4.00). The yakju containing modified nuruk showed the highest acidity (3.64 mL/10 mL), amino acidity (4.72 mL/10 mL), soluble solid ($1.20^{\circ}Bx$), and color difference (39.78). The concentration of organic acids in traditional nuruks was 212.25-312.97 mg/100 mL, whereas that in modified nuruk was 295.92 mg/100 mL. Nitrogen compound concentrations in modified nuruk (2285.89 mg/L) were 2-14 times higher than that in traditional nuruk. Nitrogen compound concentration and amino acidity are the physiochemical characteristics with the highest impact on off-flavor and browning of yakju. In order to reduce these unfavorable characteristics, material with a lower protein content should be used.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.199.1-199
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• 2003

제주민속주인 좁쌀약주의 제조를 위하여 전국에서 수집된 35종의 누룩으로부터 우수 곰팡이와 효모를 분리하였다. 수집된 누룩의 균수는 곰팡이가 6.4$\times$105~107개, 효모는 1.4$\times$104~107개로 나타났고, 이 중에서 곰팡이 169균주, 효모 103균주를 분리하였으며 전분당화력이 좋은 곰팡이 16균주와 효모 1균주를 선발하였다. 이 중에서 전분당화 균주의 효소활성을 분석한 결과 Aspergillus속으로 동정된 A8-3이 glucoamylase 활성, 액화력, xylanase 활성이 가장 높았고, Rhizopus속으로 동정된 B23-3은 당화력이 가장 우수하였다. 우수효모를 선발하기 위하여 pH, 무게 감량, 내당성, 내알코올성 등을 측정한 결과, Saccharomyces속인 A10-4가 가장 우수하였다. 같은 원료비율로 만든 누룩에 우수균주를 접종하였을 때, 단일 균주를 처리할 때보다 A8-3과 B23-3인 두 균주를 혼합하여 처리한 경우가 당화력이 높게 나타났다. 누룩을 원반형의 누룩과 팰릿(개량형) 형태로 만들어 혼합종균 배양액을 접종한 후 당화력을 측정한 결과, 비슷한 당화력을 나타내었다. 개량형 누룩을 사용하여 양조하는 경우, 좁쌀주 양조에 발효효율을 높일 수 있을 것으로 판단되었다. 수집된 누룩은 수분이 10~13%, 총당은 55~70%, 조단백질은 10~18% 조지방은 0.2~l.0%, 회분은 1.8~2.1%이었다. 본 연구에서 제조한 누룩은 수분이 12~15%, 총당은 61~7l%, 조단백질은 15~20%, 조지방은 0.4~1.5%, 회분은 1.1~1.5%이었다.