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

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

• Proceedings of the Korean Society of Life Science Conference
• /
• 2007.10a
• /
• pp.50.2-50.2
• /
• 2007

See Full Text

• Proceedings of the Korean Society of Life Science Conference
• /
• 2007.10a
• /
• pp.50.1-50.1
• /
• 2007

See Full Text

• Microbiology and Biotechnology Letters
• /
• v.27 no.3
• /
• pp.236-245
• /
• 1999

Andong Soju is a Korean traditional distilled liquor brewed with Nuruk which is cultured with wild microorganisms. To provide useful information for scientific production and systematic quality control of traditional distilled liquor, the effects of mixed culture of the alcoholic yeasts and saccharifying molds isolated from the Nuruk, and mashes on the flavor and sensory characteristics were investigated. Distillate from mashes cocultured with Saccharomyces cerevisiae and Hansenula anomala using Mucor Nuruk was compared with distillate from mashes brewed with Andong Nuruk and with distillate from plant fermented mashes to analyze their flavor characteristics. The volatile flavor compounds in distillates were analyzed by GC and GC-MS using direct injection, solvent extraction, and purge & trap methods. Alcohols such as 3-methyl-1-butanol, 2-methyl-1-propanol, 1-propanol, and 2-phenyl ethanol; aldehydes such as acetaldehyde and 2-furancar-boxaldehyde; esters such as ethyl ester of acetic acid, hexanoic acid, octanoic acid, decanoic acid; alkanes, alkenes, ketone, sulfur, and pyrone compounds were detected. Alcohols were chief components of flavor compounds. No significant difference in overall acceptability test was shown among three experimental groups(p<0.05), but Nuruk-like aroma, Kaoliangchiew-like aroma, sweet taste, and well rounded mouthfeel showed significant differences among them(p<0.05).