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Suigen, South Korea

Bal J.,Chonbuk National University | Yun S.-H.,Chonbuk National University | Yeo S.-H.,NAAS | Kim J.-M.,Wonkwang University | Kim D.-H.,Chonbuk National University
Food Microbiology | Year: 2016

Nuruk, a traditional natural starter, is extensively used in the brewing of Makgeolli, one of Korea's most popular alcoholic beverages that has been recently gaining global popularity. Thus, the quality of traditional nuruk needs to be enhanced. The nuruk mycobiome greatly influences both fermentation process as well as palatability enhancement. Limitations of culture-dependent identification restrict an accurate analysis of fungal diversity and distribution in nuruks. 454 pyrosequencing of two traditional wheat-based nuruks, prepared at two representative temperature conditions revealed a total of 153 and 53 OTUs for nuruks A and B, respectively, from a total of 33,157 ITS sequences. Phylogenetic assignments indicated that nuruk A mycobiota was dominated by the genera Aspergillus and Mucorales, whereas nuruk B by Rhizomucor. Species-level identification indicated that Mucorales sp., Aspergillus candidus, and Aspergillus cibarius predominated in nuruk A mycoflora whereas Rhizomucor pusillus, Mucorales sp., and Thermoascus crustaceus in nuruk B. The alpha diversity indices suggest nuruk A mycobiota to be more diverse than that of nuruk B at almost all time points of fermentation. Resemblances of patterns of predominant species composition and succession between culture-dependent and -independent phylogenetic analysis creates the potential to reconstruct the nuruk mycobiome in vitro, which allows the establishment of a standard inoculum for scientific comparison. © 2016 Elsevier Ltd Source

Lee S.-W.,Kyungpook National University | Yoon S.-R.,Biohealth Convergence Center | Kim G.-R.,Kyungpook National University | Woo S.-M.,Keimyung University | And 4 more authors.
Food Science and Biotechnology | Year: 2012

The effects of different nuruk contents and fermentation methods (AV, vinegar fermented in an agitated culture; SV, vinegar fermented in a static culture) on organic acids and volatile compounds in brown rice vinegars were investigated. In the SV, the contents of acetic, oxalic, tartaric, and malic acids increased with hipher contents of nuruk. Acetic, tartaric, and malic acid contents were higher in the SV than those in the AV. Volatile compounds that can affect vinegar quality, including acetic acid, isoamyl acetate, phenethyl acetate, and phenethyl alcohol were present at high concentrations in the AV. With the increase in nuruk contents in the AV, acetic acid content decreased and isoamyl acetate and phenethyl acetate content increased. No significant differences in sensory scores were observed regarding the amount of nuruk and the type of fermentation. However, electronic-nose analysis showed its potential to effectively differentiate different samples. © 2012 The Korean Society of Food Science and Technology and Springer Netherlands. Source

Kim S.-Y.,NAAS | Yoo K.-S.,Chungbuk National University | Kim J.E.,Chungbuk National University | Kim J.-S.,Chungbuk National University | And 4 more authors.
Food Science and Biotechnology | Year: 2010

A polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method was used to determine the presence and diversity of lactic acid bacteria (LAB) in takju, a traditional Korean rice wine. Bacterial DNAs were extracted from 15 commercial rice wines and amplicons of partial 16S rRNA genes were separated by DGGE and intense bands were sequenced. Lactobacillus (Lb.) paracasei, Lb. plantarum, and Leuconostoc pseudomesenteroides were detected in all samples and Lb. harbinensis and Lb. parabuchneri were found with above 80% frequency of occurrence. Unknown species of Lactobacillus were also widely detected. This result revealed that, regardless of products and raw materials, the distribution profiles of LAB in takju products have a common pattern comprising of above predominant species and, furthermore, takju can be regarded as a LAB-rich fermented food providing various probiotics. © KoSFoST and Springer 2010. Source

Liu C.-S.,Kyung Hee University | Nam T.-G.,Kyung Hee University | Han M.-W.,Korea Ginseng Corporation | Ahn S.-M.,Kyung Hee University | And 6 more authors.
Bioscience, Biotechnology and Biochemistry | Year: 2013

Oxidative stress due to the over-production of reactive oxygen species (ROS) is associated with human skin aging. This study was designed to identify the bioactive phenolics in detoxified Rhus verniciflua Stokes (DRVS) that may protect human skin against oxidative stress. Under oxidative stress caused by H2O2, the 40% (v/v) aqueous methanol extract of DRVS protected human keratinocytes in a dose-dependent manner. The expression of matrix metalloproteinase-1 (MMP-1) was also inhibited by the DRVS extract in human dermal fibroblasts-neonatal cells exposed to ultraviolet A. The major bioactive phenolics of DRVS were tentatively identified by LC/Q-TOF-ESI-MS/MS, and included gallic acid, 2-(ethoxymethoxy)-3-hydroxyphenol, fustin, a fustin isomer, tetragalloyl glucose, pentagalloyl glucose, fisetin, sulfuretin, a sulfuretin isomer, and butein. The results suggest that a DRVS extract may be effective in slowing skin aging through its antioxidative properties and by down-regulating MMP-1 expression. Further studies are needed to examine whether this effect would be mediated by the phenolics identified in this study. Source

Choi H.-S.,NAAS | Lee S.Y.,NAAS | Baek S.Y.,NAAS | Koo B.S.,NAAS | And 3 more authors.
Korean Journal of Food Science and Technology | Year: 2011

This study was conducted to provide information for improving the quality characteristics of Buckwheat Soksungjang (BWS). We determined aminotype nitrogen content, total microbial flora counts, the population of Bacillus cereus, presence of volatile compounds, fibrinolytic activity, antioxidant activity, ACE inhibition rate, and a sensory evaluation. The aminotype nitrogen increased gradually during fermentation. We found a decreasing population of B. cereus during fermentation, thus, the edible period for BWS was more than 30 days after fermentation. Acetaldehyde, butanol, and pyrazine were detected as volatile compounds after fermentation. The fibrinolytic activities of a 10%BWS water extract were high at 120.8 units compared to the control (71.6 units). In a sensory evaluation, Soksungjang with 60% added BW showed a significantly higher score (p < 0.001) for color, taste, smell, texture, and overall. The results suggest that a new type of shortened fermented soybean paste had good safety, bioactivities, and sensory characteristics within 4 weeks. © The Korean Society of Food Science and Technology. Source

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