• The Korean Journal of Mycology
• /
• v.40 no.4
• /
• pp.204-209
• /
• 2012

In this study, a novel yeast, Y111-5 for Makgeolli manufacture was selected from Nuruk yeasts, and its optimal culture condition were investigated. The Y111-5 strain was identified as Saccharomyces cerevisiae by phylogenetic analysis of 18S RNA sequence. The maximal growth was obtained when the yeast was cultivated at $30^{\circ}C$ for 15 h in the medium containing sucrose 9% and yeast extract 5%.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.8
• /
• pp.1077-1082
• /
• 2007

In this study, killer yeasts were isolated from traditional Nuruk to improve storage and suppress contaminant in food industry. Among killer yeasts, yeast K15 showed strong killer toxin activity and inhibited growth of Salmonella Typhimurium and Vibrio parahaemolyticus. Killer yeast K15 was identified with Pichia anomala by the Microlog TM 4.0 identification system and homology of the ITS sequence. Killer toxin generated from P. anomala K15 was inactivated by pronase E and suggested to be a protein. Therefore killer toxin of P. anomala K15 was thought to be safe in human such as bacteriocin. P. anomala K15 was sufficient for growth in 50% glucose and could be used to prevent contaminant in initial stages of alcohol beverage fermentation.

• Korean Journal of Food Science and Technology
• /
• v.13 no.4
• /
• pp.307-313
• /
• 1981

The components of several kinds of Sokokju (old Korean cleared rice wine) prerared in the laboratory by two steps mashing and commercial Yakju (Korean cleared rice wine) were evaluated. The Sokokju mashed with half steamed waxy rice in tile primary fermentation yielded higher contents of alcobol and extract. Especially considerable amount of pyruvate was contained in it. The commercial Yakju sample contained abundantly tartarate and citrate while dominant organic acids in the fermented mashes of Sokokju were lactate, fumarate and succinate. The taste characteristics of the Sokokju brewed with half steamed waxy rice were most acceptable to the sensory panel.

• Microbiology and Biotechnology Letters
• /
• v.51 no.1
• /
• pp.93-98
• /
• 2023

Nuruk is a starter culture of Korea manufactured by spontaneous fermentation of grains. We isolated bacteria of the genera Bacillus and Staphylococcus, and lactic acid bacteria (LAB) from eight commercial nuruk samples collected from four districts of Korea using selective agar media and identified them based current taxonomic standards. Bacillus was detected in all samples, but Staphylococcus or LAB were not detected in three samples. In seven samples, except one sample scored the highest cell number of LAB, Bacillus and Staphylococcus were counted as the highest and the lowest numbers, respectively. Six species of Bacillus were identified, and B. subtilis, B. velezensis, and B. licheniformis were predominant species. Nine species of coagulase-negative Staphylococcus were identified, and the predominance of S. pseudoxylosus and S. saprophyticus was confirmed. Ten species of LAB including Enterococcus, Lactobacillus and close relatives, Pediococcus, and Weissella were identified. P. pentosaceus was identified as the predominant species.

• Culinary science and hospitality research
• /
• v.21 no.6
• /
• pp.103-119
• /
• 2015

This study was carried out to evaluate the quality of characteristics of Takju, Yakju, and spirit made from Bunkuk(flour), Phellinus linteus and Ginger kuk. The sacharogenic power of Nuruks and pH, brix, acidity, cell numbers of yeast, and alcohol content of Deotsuls were analysed; flavors, organic acids, and sensory evaluation of Takju, Yakju, and spirit were employed in the analysis of this current study. Results showed that the saccharogenic power of Phellinus linteus kuk after fermentation of Nuruks showed the highest level, and Phellinus linteus kuk and Ginger kuk showed the same level after dry Nuruks. During fermentation of Deotsuls, pH and brix decreased with increased fermentation time, while acidity increased with increased fermentation time. Cell numbers of yeast were found to be at the highest level in Phellinus linteus kuk on the first day of fermentation, and it was the same result in the final stage(p<0.05). Alcohol content increased with an increase in fermentation time, and showed no significant difference between control and test in the final stage of fermentation. In terms of analysis of flavor components, acetone and n-amyl alcohol were not detected in Takju, Yakju, and spirit. n-butanol was detected at the highest value, followed by i-amyl alcohol. Fusel oil was detected at the highest level in spirit fermented by Bunkuk. In analysis of organic acids, lactic acid showed the highest content followed by acetic acid. Very small amounts of acetic acid were detected in the spirit and other organic acids were not detected. In sensory evaluation, Takju, Yakju, and spirit made from Phellinus linteus kuk showed the highest score. As a result of this study, Phellinus linteus kuk presented the most desirable Nuruk in order to make Takju, Yakju, and spirit.

• Microbiology and Biotechnology Letters
• /
• v.39 no.1
• /
• pp.56-62
• /
• 2011

We investigated quality characteristics of Seoktanju (one of the Korean traditional rice wine) which was fermented using five kinds of Korean commercial Nuruks. The purpose of this study was to research what effects on the quality of Seoktanju by using different Nuruks. We analyzed general component such as each mash's temperature change patterns, pH, titrable acidities, reducing sugar contents, volatile acids, and sugar contents during fermentation periods and studied sensory evaluation of produced Seoktanju (10 days). On the whole, temperature change patterns in the each mashes were depend on room temperature. All Seoktanju's pH was reduced rapidly up to three days after first mashing (pH 3.13-3.57) and after that was increased gradually. The end of fermentation pH was pH 3.6-4.05. Mostly, acidities were indicated high(0.59%) and Nuruk-B was showed highest acid value. These results seems to be different as occasion organic acids producing activity depend on the number of yeast, material contents, optimal temperature in the each mashes by fungi and lactic acid bacteria in Nuruks. In reducing sugar contents and sugar contents, Nuruk-C treatment were showed the highest value with 5.36%, $23^{\circ}brix$, respectively and alcohol content was lowest with 8.6%. In the five kinds of reproduced Seoktanju, alcohol content was the highest in the treated Nuruk-A group. Volatile acid value was the highest with 132.6~263.7 ppm at the 3 day after first mashing day but as the fermentation time goes on, it was reduced sharply by 5.25~5.94 ppm. Sensory evaluation was performed with 5 point scale, the Seoktanju using Nuruk-D was presented by 4 point, while Nuruk-A was presented lowest by 2.77 point on overall acceptability.

• Korean Journal of Agricultural Science
• /
• v.12 no.2
• /
• pp.242-252
• /
• 1985

In order to get information on the ecology of rice false smut, germination ability and pathogenicity of sclerotia and chlamydospores of the pathogen, environmental conditions affecting the disease outbreak and varietal resistance have been investigated. 1. The degree of outbreak of rice false smut was higher in the upland rice in comparison with the paddy field rice in respect to the number of affected grains per ear, the size and weight of smut balls formed on affected grains as well as the ratio of sclerotial formation produced on smut balls. 2. Germination percentage and days required for germination of overwintered sclerotia placed on the soil surface in July were 81% and 19 days, respectively, while those of overwintered sclerotia treated in May were 60-70% and 41 days. Sclerotia placed on the soil surface or under 1 cm depth of the soil surface and incubated at $25-30^{\circ}C$ were germinated well, whereas those placed under 3 cm or 5 cm depth of the soil surface were not germinated at all. Germinability and stroma productivity of sclerotia were reduced when the sclerotia were cutted into small pieces. 3. The average number of stroma formed on a sclerotium was six and that of perithecia formed in a stroma was about 50 to 140. 4. Percentage of germination of chlamydospores on the yellow balls was very high and was decreased as the color of the balls being darken with maturation. 5. Panicle of rice plants were successfully infected by injection inoculation with suspention of ascospores and chlamydospores of the pathogen to the sheaths at the booting stages, while seeding infection by spraying with suspensions of chlamydospores was unsuccessful. 6. More number of infected grains was distributed on basal parts of an affected ear than that of infected ones distributed upper parts of the ear, when the affected ear was divided into five parts from its basal portion to the apical of the ear. 7. The occurrence of the disease was more severe in the late maturing varieties of rice in comparison with the early maturing varieties. 8. When the level of nitrogen applied was increased, the incidence of disease increased, and the infection percentage of the disease was increased as the transplanting date was delayed. 9. The weight of panicles and 1000 kernels and the ratio of ripenness were reduced, and the contamination degree of grains with chlamydospores were increased as the number of smut balls per panicle were increased.

• Korean Journal of Food Science and Technology
• /
• v.46 no.1
• /
• pp.25-32
• /
• 2014

This study aimed to analyze the general ingredients and volatile compounds of ipguk (koji) and nuruk soju distilled under reduced pressure (RP) or atmospheric pressure (AP) conditions. After the secondary brewing process, soju made using ipguk had a final fermentation alcohol content of $18.0{\pm}0.6%$, whereas soju made using nuruk reached $14.3{\pm}1.7%$. The level of succinic acid was the highest in ipguk soju ($7,685.33{\pm}34.97$ ppm), but nuruk soju also showed a high level of succinic acid ($5,945.79{\pm}76.30$ ppm) after its final fermentation. In an analysis of fusel alcohol content, the level of n-propanol in ipguk soju (389.10-397.27 ppm) was similar under different RP (50 cm Hg and 60 cm Hg) and AP conditions ($80^{\circ}C$ and $90^{\circ}C$). Under RP and AP conditions, the isoamyl alcohol/isobutanol (A/B) ratio was similar, ranging from 1.32-1.35. In ipguk soju distilled under RP conditions of 50 cm Hg and 60 cm Hg, the amount of the toxic component, acetaldehyde, was 8.59 and 9.27 ppm, respectively. Under AP conditions, the amount of acetaldehyde in ipguk soju distilled at 80 and $90^{\circ}C$ was 9.80 and 10.63 ppm, respectively, indicating that the amount of acetaldehyde did not differ depending on the distilling method used. These results suggest that the liquor distilled from the mash produced using ipguk under RP conditions may be of a higher quality.

• Microbiology and Biotechnology Letters
• /
• v.26 no.5
• /
• pp.456-464
• /
• 1998

For the standardization and quality improvement of traditional Korean Nuruk, 10 strains of fungi, which were isolated from Nuruks and showed good productivity of the saccharogenic and dextrinogenic enzymes, acid and flavor, were selected and their enzymological characteristics and identification were carried out. Aspergillus spp. and Rhizopus sp. showed a high liquefying activity without regard to cultivation time, whereas the majority of strains except for Rhizopus sp. had decreasing saccharifying activity in proportion to the increase in cultivation time. Aspergillus spp. No.17-2, No.17-6 and Rhizopus sp. No.18-1 showed high liquefying and saccharifying activity after 15 and 30 day cultivation. The optimum temperature of most of these saccharogenic and dextrinogenic enzymes was from 40$^{\circ}C$ to 60$^{\circ}C$, and their optimum pH was extensive between pH 3 and pH 11. But Penicillium spp.(2 strains) and Rhizopus sp. showed low activity under the alkalic and acidic conditions. Among these isolated strains, 5 strains which had shown the high productivity of materials were identified as Aspergillus oryzae NR3-6 and Aspergillus oryzae NR17-6, Aspergillus penicilloides NR12-1, Penicillium expansum NR7-7 and Rhizopus oryzee NRl8-1, respectively. Five kinds of mixed culture were carried out and all of them showed a better productivity of saccharogenic and dextrinogenic enzymes than single culture. These results indicate that it is possible to make traditional Korean liquors of good quality by using these fungi.

• Applied Biological Chemistry
• /
• v.51 no.2
• /
• pp.142-147
• /
• 2008

Nuruk is the Korean traditional Koji that contains various microorganisms and has been used to make the traditional fermented foods including alcoholic beverages. Rhizopus oryzae KSD-815 was isolated from the alcohol-fermenting Nuruk used for manufacturing traditional alcohol. In this study, the authors reported the isolation and identification of four lipids from the Nuruk (Rhizopus oryzae KSD-815) that inoculated wheat with Rhizopus oryzae KSD-815. The dried and powdered Nuruk (Rhizopus oryzae KSD-815) were extracted three times at room temperature with 80% aqueous MeOH. The extracts were partitioned with EtOAc, n-BuOH, and water, successively. The EtOAc extract was suspended in 80% MeOH and partitioned repeatedly with n-hexane. From the n-hexane fraction, four lipids were isolated through the repeated silica gel and ODS column chromatographies. According to the results of physico-chemical data including NMR, GC and MS, the chemical structures of the compounds were determined as linolenic acid methyl ester (1), palmitic acid methyl ester (2), linoleic acid (3), palmitic acid (4). Cytotoxicity was evaluated in huamn breast cancer cells, MDA-MB-231 and human hepatocarcinoma, SK-HEP-1 cells using MTT assay. Exposure of compounds 1 and 3 led to a dose-dependent inhibition of cell viability in both cancer cell lines. In addition, treatment of RAW264.7 cells with compound 3 caused inhibition of lipopolysaccharide/interferon-${\gamma}$-induced nitric oxide production.