γ-PGA(poly-γ-glutamic acid) is an unusual anionic polypeptide that is made of D-and L-glutamic acid units connected by amide linkages between α-amino and γ-carboxylic acid groups. γ-PGA has been isolated from many kinds of organisms. Many Bacillus strains produce γ-PGA as a capsular material of an extracellular viscous material. It is safe for eating as a viscosity element of fermented soybean products such as Chungkookjang and Natto. It is biodegradable, edible and nontoxic toward humans and the environment and its molecular weight varies from ten thousand to several hundred thousand depending on the kinds of strains used. Therefore, potential applications of γ-PGA and its derivatives have been of interest in the past few years in a broad range of industrial fields such as food, cosmetics, medicine, water-treatment, etc. In this study, a bacterium, Bacillus subtilis GS-2 isolated from the Korean traditional seasoning food, Chungkookjang could produce a large amount of γ-PGA with high productivity and had a simple nutrient requirement. Based on carbon utilization pattern and partial 16S rRNA sequence analysis, the GS-2 strain was identified as B. subtilis. The determination of purified γ-PGA was confirmed with thin layer chromatography (TLC), high performance liquid chromatography (HPLC), fourier transform infrared (FT-IR) spectra, and 1 H-nuclear magnetic resonance ( 1 H-NMR) spectroscopy.

국문요약Poly-γ-glutamic Acid(γ-PGA)를 다량 생산하는 균주를 우리나라의 전통발효식품인 청국장으로부터 Bacillus subtilis GS-2를 분리하였다. 이 균은 glutamic acid 의존형 균으로, 이 균에 의한 γ-PGA 생산 최적 조건을 검토한 바, 단순배 지(L-glutamic acid 2.0%, glucose 1.0%, NH4Cl 0.5%, KH2PO4 0.05%, MgSO4․7H2O 0.01%, pH 7.0)로 진탕배양(220 rpm) 하였을 때, 배양시간 48시간, 최적온도 33℃, 그리고 초기 pH 6.5로 나타났다. 영양원으로 glutamic acid 3%, sucrose 3%, NH4Cl 0.25%, KH2PO4 0.15%, MgSO4․7H2O 0.015%에서 γ-PGA 최대 생산량이 31.0 g/ℓ이었다.

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In this study, effect of resveratrol concentration on wine taste was investigated. Content of resveratrol in 14 different wines were quantified using HPLC. The resveratrol concentrations in the Australian wine samples (grape species: Syrah) with 3 vintage years were analyzed and different concentrations of resveratrol were observed (2.89~3.84 mg/L). Variation in wine grape species with the same wine manufacturer (Chile, 2006) and variation in different manufacturing country of origin with same wine grape species (Cabernet Sauvignon, 2006) also produced the variations in resveratrol concentration. The preference analysis (color, aroma, taste, astringency and overall acceptability) of the sample wines were determined by 15 panelists using 5-point hedonic scale. When the analysis results of the resveratrol concentrations in the sample wines were compared with the preference analysis of sample wines, the resveratrol concentration in the wine produced the positive effects in the wine preference analysis in the factors of aroma, taste and color.

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