• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.403-410
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• 2021

This paper aimed to increase the functionality and competitiveness of rice bran, which is used as an alternative food and cosmetic raw material, through fermentation. As a result of comparing the enzyme activity of 𝛼-amylase, CMCase, 𝛽-glucosidase, protease, etc. of fermented rice bran using standard strains with 6 strains with excellent enzyme activity among 50 strains of Saccharomycopsis fibuligera isolated from 5 types of Nuruk, A8 strain showed excellent enzyme activity of 13.7%, 21.1%, 50.3%, and 10.0% compared to the KCTC 7806 strain. As a result of the ABTS and DPPH tests as a result of fermentation, it was confirmed that rice bran fermented with A8 had 1.12 times and 1.28 times more antioxidant activity than rice bran fermented with KCTC 7806 strain. In this paper, it was possible to confirm the S. fibuligera A8 strain superior to the standard S. fibuligera strain KCTC 7806.

• Culinary science and hospitality research
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• v.21 no.3
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• pp.232-247
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• 2015

This study was carried out to evaluate the quality of characteristics of the Takju, Yakju, spirit made by various pulse crop Nuruks which were made by Whyangonkuk(whole wheat, mung beans), Naebubijeonkuk mung beans, wheat flour, millet), Daedukuk(whole wheat, soybean). pH, Brix, total acidity, cell numbers of yeast and alcohol content of brews were analysed and flavors, organic acids, sensory evaluation of Takju, Yakju, and spirit were employed to analyze for current study. Results showed that pH value of Whyangonkuk brews during fermentation decreased the lowest, and Brix value also decreased. Total acidity of Whyangonkuk at the initial and final stage of fermentation revealed the most. Alcohol contents of Naebubijeonkuk brew presented the highest at the initial stage of fermentation, but there were no significant differences among Whyangonkuk, Naebubijeonkuk and Daedukuk at the final stage of fermentation. Cell numbers of yeast were found the most in Daedukuk at the first stage of fermentation, and cell numbers started to decrease after 2 days, but there were no significant differences at the final stage(p<0.05). In terms of analysis of flavor components, acetone and n-amyl alcohol were not detected in Takju, Yakju, and spirit. n-butanol was detected the most value followed by i-amyl alcohol. Fusel oil were detected the highest level at spirit, but no differences among Takju, Yakju and spirit. In analysis of organic acids, fumaric acid and formic acid were detected in Takju and Yakju. while 7 kind of organic acids were detected. Lactic acid showed the highest level in organic acid analysis. Takju and Yakju made by Whyangonkuk showed the highest score, and Daedukuk showed the opposite result but there were no differences in spirit made by Whyangonkuk, Naebubijeonkuk, and Daedukuk. As a result of this study, Whyangonkuk presented the most desirable Nuruk.

• Applied Biological Chemistry
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• v.13 no.1
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• pp.105-109
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• 1970

Thiamin in the various materials which used for Takja braving was determined and its quantitative changes in the Takju mashes which were mashed with polished rice and wheat flour respectively using Nuruk only for the enzyme source, and with wheat flour and corn powder respectively using Nuruk and Koji, were checked at 24 hours intervals during the whole brewing period. The results obtained were as follows. a) The thiamin contents in 100 grams of each materials were: Polished rice 107.8${\gamma}$ Wheat Pour 185.0${\gamma}$ Corn powder 410.2${\gamma}$ Nuruk 347.4${\gamma}$ Koji of wheat flour 170.1${\gamma}$ Koji of corn powder 257.3${\gamma}$ b) About 40 to 50 percent of thiamin in the polished rice, wheat flour and, corn powder were losed by steaming at 10 wounds for 50 minutes. c) The quantitative changes of thiamin in the Takju meshes showed a similar tendency. Thiamin contents were decreased markedly during 2 days after mashing but thereafter, almost unchanged till the mashes were ripened. Its decreasing rates in tile two plots uses Nuruk and Koji wereless thaw those in the two plots used Nuruk only. d) Approximately 6${\gamma}$ of thiamin was determined in 100 ml. of the ripened mash of the rice plot and 7.5${\gamma}$ in tire whet flour plot in the case of using Nuruk only. 12.4${\gamma}$ of thiamin was determined in 100 ml. of the ripened mash of the wheat flour plot and 15.4${\gamma}$in the corn powder plot in the case of using Nuruk and Koji. e) It was assumed that 2.4 to 3.5${\gamma}$ of thiamin were contained in 100 ml. of finished Takju of the two plots used Nuruk only and 5 to 7${\gamma}$ in the two plots used Nuruk and Koji. f) About 43.7${\gamma}$ of thiamin were determined in 100 grams of Takju cake of the rice plot and 56.1${\gamma}$ in the wheat flour plat used Nuruk only, and 81.4${\gamma}$ in the corn powder plot and 57.7${\gamma}$ in the wheat flour plot used Nuruk and Koji.

• Food Science and Preservation
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• v.22 no.6
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• pp.920-925
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• 2015

The microbial composition in Nuruk, a Korean cereal fermentation starter, is a critical factor for the quality and organoleptic properties of traditional alcoholic beverages. This study was aimed at monitoring the compositional change and enzyme activity of culturable lactic acid bacteria (LAB) in two types of Nuruk fermented at different temperatures. All culturable LAB were isolated at various time points (0, 3, 6, 10, 20, and 30 days) and identified by 16S rRNA sequencing. In traditional Nuruk type A (TN-A), which was fermented at $36^{\circ}C$, the population of total culturable LAB during the fermentation period was between $10^4$ and $10^5$ log CFU/mL. On the other hand, the LAB population in traditional Nuruk type B (TN-B) fermented at $45^{\circ}C$ (primary fermentation for 10 days) and $35^{\circ}C$ (secondary fermentation for 20 days) was $10^2$ log CFU/mL; however, these bacteria could not be detected after 6 days. Major LAB strains were identified in both Nuruk types: (1) from the MRS-culture of TN-A, Pediococcus pentosaceus at 3-30 days; (2) from MRS-culture of TN-B, P. pentosaceus at 3 days and Enterococcus hirae at 6 days. The protease activities of the dominant LAB isolated from the TN-A and TN-B cultures were within the ranges of 0.64~1.03 mg/mL and 0.74~0.81 mg/mL (tyrosine content), respectively, whereas the ${\alpha}$-amylase activities were 0.75~0.98 mg/mL and 0.78~0.79 mg/mL (amylose content), respectively.

• Food Science and Preservation
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• v.30 no.4
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• pp.669-682
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• 2023

The production of distilled soju by fermenting nonsteamed rice was evaluated using commercial enzyme products. White koji and modified nuruk had alpha-amylase activities of 31.90 U/g and 3,532.71 U/g, respectively, and gluco-amylase activities of 698.32 U/g and 4,899.58 U/g, respectively. The enzyme products had activities of 5,604.15-225,182.00 U/g and 13,517.41-120,822.41 U/g, respectively. At enzyme concentrations of >800 mg/L, the Chung-moo-purified enzyme had an alcohol productivity of ≥19%. Nurukzyme R400, Sanferm Yied, and Diazyme X4 exhibited alcohol productivities of >19% at concentrations of >600 mg/L. The alcohol content of the vacuum distillates was 41.31%-44.86%. The volatile component with the alcohol content adjusted to 25% was analyzed and principal component analysis was performed. The volatile components in white koji, Diazyme X4, and Sanferm Yield were similar. The modified nuruk treatment group had a relatively high ethyl lactate content compared to the white koji treatment group. The Nurukzyme R400 treatment group had high contents of butyric acid and ethyl butyrate. The Chung-moo-purified enzyme was characterized by a low component content. Thus, when enzyme products were used in nonsteamed rice fermentation, no effect on the alcohol productivity and quality of vacuum distilled soju was observed, suggesting that it can replace white koji and modified nuruk.

• KSBB Journal
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• v.19 no.4
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• pp.301-307
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• 2004

The characteristics of the a-amylase of Aspergillus coreanus NR 15-1 isolated from traditional Korean Nuruk have been carried out. The a-amylase of A. coreanus NR 15-1 was purified by ammonium sulfate precipitation followed by column chromatographies on CM-cellulose, DEAE-cellulose, Sephadex G-100 gel filtration and hydroxyapatite. The a-amylase was purified 78-fold with a yield of 8.7%. The molecular weight of the a-amylase was estimated to be 49 kDa by Sephadex G-100 gel filtration and 51 kDa by SDS-polyacrylamide gel eletrophoresis. These experimental results suggested that the purified enzyme might be monomer. The enzyme was stable between pH 4 and 11. The optimum pH was 5.0. The optimum temperature for enzyme was 45$^{\circ}C$ and the enzyme was stable up to 50$^{\circ}C$. The enzyme was significantly inhibited by 1 mM N-bromosuccinimide. These results suggested that tryptophan residue was involved in the active site of a-amylase. The enzyme was identified as a-amylase because the reaction products of soluble starch hydrolyzed by the purified enzyme was oligosaccharide by thin layer chromatography.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.6
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• pp.880-886
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• 2010

In this study, volatile compounds in liquor distilled from mash produced using koji or nuruk under reduced or atmospheric pressure were analyzed and eventually, the proper starter material and distillation method was selected. Acetaldehyde was detected two or three times more in the liquor distilled under the atmospheric pressure than under the reduced pressure. Furfural was only detected in the liquor distilled under the atmospheric pressure. Esters were detected more in the liquor distilled under the atmospheric pressure than the reduced pressure. Ethyl pelargonate and 2-phenyl ethanol were particularly detected two times more in the liquor distilled under the atmospheric pressure than the reduced pressure. Methanol was detected two times more in the liquor made with nuruk than that with koji. These results suggest that the liquor distilled from the mash produced using koji under the reduced pressure may have the better quality.

• Korean Journal of Food Science and Technology
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• v.52 no.5
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• pp.529-537
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• 2020

This study was carried out to confirm changes in the microbial community and physicochemical characteristics of Korean traditional Makgeolli during fermentation by yeast as a fermentation starter. We demonstrate that the microbial community during fermentation affects the quality of Makgeolli. At the species level, Pediococcus pentosaceus, Weissella confusa, Pantoea vagans, and Lactobacillus graminis were dominant on fermentation mix, after 1-2 days, in the control group without yeast treatment. Acid production in the control group was higher than that in the yeast-treated group. P. pentosaceus was dominant throughout the fermentation process, and the proportion of P. vagans remarkably decreased following yeast addition. Considering quality characteristics, the alcohol content rapidly increased after yeast addition, and the lactic acid content was lower in the yeast-treated group than in the control. These results suggest that the rapid increase in alcohol at the start of fermentation inhibits the growth of lactic acid-producing bacteria. The addition of yeast may contribute to the reduction in the high amount of lactic acid, which can be one of the causes of changes in Makgeolli quality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.376-385
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• 2019

This study was undertaken is to isolate brewing yeast suitable for rice beer fermentation from the traditional Nuruk, and to identify the brewing ability of the isolated yeast. After 6 months of research, four brewing yeast isolated from traditional Nuruk showed a normal fermentation pattern in terms of physicochemical data (pH, brix, alcohol content) and higher vitality, as compared to commercial brewing yeast. The concentrations of higher alcohol and ester, that impart the aroma to beer, were 78.4 to 106.5 ppm and 15.1 to 29.3 ppm, respectively. In particular, S. cerevisiae (KCCM 90313) bestowed significantly higher contents of higher alcohol and ester concentrations than rice beer prepared from commercial yeast. We conclude that the four variants of yeast isolated from traditional Nuruk are potentially suitable for manufacturing rice beer. Especially, the S. cevisiae (KCCM 90313) yeast shows excellent yeast activity and aroma production, thereby displaying potential application for manufacturing rice beer in the future.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.357-363
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• 2011

This study focus was primarily the development of liquid starters for Aspergillus oryzae and Aspergillus niger prepared with wheat bran as a low cost culture medium. For the preparation of the liquid media wheat bran was added at rates of 0, 5, 10, 15 and 20% and the Aspergillus sp. strains were then inoculated to these prepared broths. The results indicated that the more that wheat bran was contained in the medium, the more mycelia was produced for A. oryzae and A. niger. The highest enzyme activities were obtained with a 10~15% adding rate of wheat bran for both strains. Changes in the enzyme activities of the liquid starters during various incubation times (0, 24, 48, 72 and 96 hrs), indicated that the highest enzyme activities were seen between 48 and 72 hrs of culture. In addition, a comparative study was carried out on the production of enzymes using wheat as a substrate in nuruk, with liquid starter made from fermented agents according to the same concentrations used with the wheat bran. The pH, acidity, amino acidity, reducing sugar content and enzyme activity (${\alpha}$-amylase, glucoamylase, acidic protease) of wheat nuruk made with liquid starter were compared with those of wheat nuruk made with solid starter. The results suggest that the liquid starter is superior in both cases.