• 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.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.310-315
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• 2007

To investigate the effect of lactic acid bacteria in Andong-Soju fermentation and traditional nuruk maturation, several lactic acid bacteria were isolated from the Andong-Soju fermentation broth and traditionally matured nuruks using Lactobacilli MRS agar containing bromocresol purple. Among the isolated bacteria, ADS-L1 showed the highest lactic acid production and was dominant species in fermentation broth. Based on physiological characteristics and 16S rDNA sequencing results, the ADS-L1 was identified as Pediococcus acidilactici. The ADS-L1 grew well at $50^{\circ}C$, and under the acidic conditions at pH 4, whereas the ADS-L1 failed to grew by treatments of 12% (w/v) ethanol or 0.01N HCl. Considering the high temperature of nuruk above $50^{\circ}C$ during nuruk maturation and the high ethanol concentration of broth above 12% at the end-stage of Andong-Soju fermentation, these results suggested that the ADS-L1 is popular in matured nuruks and plays role in the early-stage of fermentation. Analysis of pH, brix, reducing sugar content, lactic acid production, and cell growth during the cultivation of ADS-L1 further suggested that the ADS-L1 may contribute the prevention of contamination by rapid and steady acidification of broth, and do not cause problems by rapid death at the end-stage of fermentation.

• 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.

• The Korean Journal of Mycology
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• v.30 no.1
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• pp.61-65
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• 2002

The objectives of this study were to find the nuruk fungal isolate for Korean traditional rice wine and to compare the tastes of rice wines made with its single inoculum. The fungal isolates including the species of Absidia, Mucor, Rhizopus and Aspergillus were used for Korean traditional rice-wine production. The four species were cultured and measured for productions of amylase under various water contents. The four different species tested were different in their growth under the rice cereals with different moisture contents; the species of Absidia and Rhizopus grew better compared to the other species under the lower moisture conditions. The tastes and alcohol concentrations of the rice-wines made with each different inoculum were compared with those of commercial rice wines made with traditional method. As a result, it was speculated that the traditional rice wines were made with nuruk, which is mainly composed of Zygomycetous fungi, such as Absidia, Mucor, and Rhzopus. Also, it was strongly suggested that the traditional nuruk might not be a source of amylase, but a source of fungal inoculum.

• Korean Journal of Oriental Medicine
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• v.16 no.1
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• pp.173-178
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• 2010

The purpose of this study was investigation of quantitative analysis of marker substances in solid fermented Angelicae Gigantis Radix by High performance liquid chromatography(HPLC). HPLC was performed for determination of nodakenin and decursin in solid fermented Angelicae Gigantis Radix extract, the separation method was performed on C18 column ($250\;mm\;{\times}\;4.6\;mm$, $5\;{\mu}m$, RS tech) using gradient solvent mixtures of water-acetonitrile with photodiode array detector (330 nm). The flow rate was 1.0 ml/min. Retention time of nodakenin and decursin was about 11.47, 46.79 min and linearity of calibration was showed good result(r2=0.9999, 0.9999), respectively. Content of nodakenin was $0.76\;{\pm}\;0.02%$ in control, $0.31\;{\pm}\;0.00%$ in Angelicae Gigantis Radix extract fermented with Paecilomyces japonica(SDT)(p<0.01), $0.51\;{\pm}\;0.02%$ in Angelicae Gigantis Radix extract fermented with Ganoderma lucidum(SYT)(p<0.01), $0.82\;{\pm}\;0.03%$ in Angelicae Gigantis Radix extract fermented with honey(SST)(p<0.05) and $0.88\;{\pm}\;0.01%$ in Angelicae Gigantis Radix extract fermented with Nuruk(SNT)(p<0.01). Content of decursin was $4.50\;{\pm}\;0.08%$ in control, $2.90\;{\pm}\;0.05%$ in Angelicae Gigantis Radix extract fermented with Paecilomyces japonica(SDT)(p<0.01), $2.65\;{\pm}\;0.08%$ in Angelicae Gigantis Radix extract fermented with Ganoderma lucidum(SYT)(p<0.01), $4.46\;{\pm}\;0.11%$ in Angelicae Gigantis Radix extract fermented with honey(SST) and $4.73\;{\pm}\;0.04%$ in Angelicae Gigantis Radix extract fermented with Nuruk(SNT)(p<0.05), respectively.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.407-412
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• 2014

A number of Saccharomycopsis fibuligera strains that can hydrolyse and utilize starch as a carbon source were isolated from nuruk, a traditional Korean starter for rice wine fermentation, and their specific growth rates on starch-containing medium were compared to choose the prominent strain. S. fibuligera strain MBY1320 showed a higher growth rate at $42^{\circ}C$ than that of strain S. fibuligera KCTC7806, indicating that S. fibuligera MBY1320 has more thermo-tolerant machinery for starch hydrolysis and utilization than KCTC7806. Although the activity of ${\alpha}$-amylase at $30^{\circ}C$ was significantly lower for S. fibuligera MBY1320 than KCTC7806 (3,812.5 U vs. 14,878.5 U), S. fibuligera MBY1320 showed a much higher glucoamylase activity at $42^{\circ}C$ than S. fibuligera KCTC7806 (5,048.9 U vs. 13,152.3 U). Thus, a new S. fibuligera strain, with a higher starch-hydrolysing activity at elevated temperatures than that of other types of strain, this study reports.

• Korean Journal of Oriental Medicine
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• v.15 no.2
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• pp.119-124
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• 2009

The purpose of this study was investigation of quantitative analysis of marker substances in Paeonia lactiflora extracts by solid fermentation. High performance liquid chromatography (HPLC) for the determination of albiflorin and paeoniflorin in P. lactiflora extracts by solid fermentation, the separation method was performed on C18 column ($250\;mm\;{\times}\;4.6\;mm$, $5\;{\mu}m$, RS tech) using gradient solvent mixtures of water-acetonitrile with photodiode array detector (230nm). The flow rate was 1.0 ml/min. Retention time of albiflorin and paeoniflorin was about 28.88, 31.92 min and linearity of calibration was showed good result(r2 = 0.9998, 0.9996), respectively. Content of albiflorin was $0.090\;{\pm}\;0.03%$ in P. lactiflora extract(control), $0.102\;{\pm}\;0.00%$ in P. lactiflora extract fermented with Paecilomyces japonica, $0.056\;{\pm}\;0.01%$ in P. lactiflora extract fermented with Ganoderma lucidum, $0.093\;{\pm}\;0.00%$ in P. lactiflora extract fermented with honey and $0.046\;{\pm}\;0.00%$ in P. lactiflora extract fermented with Nuruk. Content of paeoniflorin was $4.506\;{\pm}\;0.13%$ in control, $2.599\;{\pm}\;0.04%$ in P. lactiflora extract fermented with Paecilomyces japonica, $1.222\;{\pm}\;0.03%$ in P. lactiflora extract fermented with Ganoderma lucidum, $2.750\;{\pm}\;0.05%$ in P. lactiflora extract fermented with honey and $0.847\;{\pm}\;0.00%$ in P. lactiflora extract fermented with Nuruk, respectively. Content of the marker substances did not increase in all fermentation experiment group.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.9
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• pp.1264-1269
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• 2015

To evaluate the functional effect of ornithine produced by isolated lactic acid bacteria, we examined the anti-lipid accumulation effect of ornithine produced by isolate lactic acid bacteria on 3T3-L1 cells. Lactic acid bacteria (Pediococcus strain) were isolated from nuruk, which is made from wheat, rice, and barley (whole grain, grits, or flour) by fermenting microorganisms (Aspergillus, Rhizopus, and yeasts). Pediococcus strain was identified by 16S rDNA sequencing analyses, and cells were collected by centrifugation and developed as an ornithine starter. makgeolli, an ornithine-containing Korean traditional alcoholic beverage, was made with isolated lactic acid bacteria and arginine. makgeolli was made with the help of ornithine starter using a makgeolli making kit. We evaluated the anti-proliferation effect of ornithine makgeolli on 3T3-L1 cells. To determine the anti-proliferation effect of ornithine makgeolli on preadipocytes, lipid droplets were quantified and stained with Oil Red O. makgeolli made with ornithine starter and arginine showed a 3-fold higher concentration of ornithine compared to makgeolli without starter and arginine. In the results of 3T3-L1 cell line experiment, lipid accumulation was significantly reduced by adding 0.05 mg/mL of ornithine makgeolli compare to the control (adipocyte without sample). In conclusion, ornithine makgeolli containing ornithine starter isolated from nuruk showed an anti-lipid accumulation effect with increased ornithine content without toxicity.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.319-324
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• 2012

Production of liquid starters using wheat bran as a medium for Rhizopus oryzae N174 and the changes in their characteristics noted during storage were investigated in this study. The optimal culture conditions of the liquid starters were determined to be 5~15% (w/v) wheat bran and 48~72 hrs of incubation. The effects of liquid starters with different storage periods and temperatures (-18, 4, 10 and $25^{\circ}C$) on the quality of wheat nuruk were evaluated. According to the results of the pH, acidity, reducing sugar and enzyme activities, it was found that liquid starter using wheat bran preserved for one day, at any temperature, is the best method of storage for seed cultures for R. oryzae N174.

• The Korean Journal of Mycology
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• v.24 no.4 s.79
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• pp.280-292
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• 1996

The fungal isolates of Mucorales, directly collected from Korean traditional raw materials of Nuruk (raw material for Korean rice wine) and Meju (raw material for Korean soysauces), were compared with those of Rhizopus oryzae purchased. The fungal isolates of Rhizopus, Mucor, and Absidia mostly identified as based on the morphological observations, were evaluated with the PCR-polymorphic bands. The PCR-polymorphic bands of the genomic DNA reacted with the primers of OPD series tenmer were various, but showed averaged 4 to 6 in the agarose-electrophoresis. The dissimilarity coefficient (DC) between two isolates were compared by the cluster analyses, dendrogams and polar ordinations. The isolates of R. oryzae known. showed several groupings within the lower value of DC and were divided to two groups of amylo-process and other fungi with other purposes. The isolates unidentified were identified by the DC made of this results. Taxonomy of these isolates made by the morphological observations were consistent with those resulted above in most case but not in all aspects. More works were needed with the isolates known for detail informations of Mucorales.