• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.36-44
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• 1999

Samjangs which were prepared using magjang, traditional doenjang, and mixture of traditional doenjang and magjang were stored. Characteristics of the stored samjangs were investigated. Maximum titratable acidity was shown in traditional doenjang after 30 day of storage. Total sugar in samjangs decreased while reducing sugar increased to $11.45{\sim}12.35%$ from $8.44{\sim}9.29%$ after 40 days. Amino type nitrogen predominantly increased to $337.3{\sim}381.1\;mg%$ after 40 days from $48{\sim}53\;mg%$ of initial period of preparation. Among the free amino acids the content of glutamic acid $(202.6{\sim}464.6\;mg/100g)$ was highest and others were not too much changed. Forty two components including 7 alcohols, 4 esters, 13 acids, 6 aldehydes, 5 phenols, 3 pyrazines and others were found in samjangs. Ethanol, acetic acid ethyl ester and 2-phenylethanol were found in all treatments and ethanol, acetic acid ethyl ester, phenylacetaldehyde, butanoic acid, acetic acid, 3-methyl butanoic acid and 2,4-hexadienoic acid might be major volatile components considering of high peak area. 2-Phenylethanol, butandioic acid ethyl ester, butanoic acid and 2-methyl-2-butenoic acid were higher than other components in samjang with magjang while ethanol, acetic acid, 2,4-hexadienoic acid were in samjang with traditional doenjang and 3-methyl butanoic acid, acetic acid ethyl ester and methyl pentanoic acid were in the mixed treatment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.7
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• pp.1016-1027
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• 2015

This study collected 120 figs, classified them into six degrees of maturity according to hardness values, and analyzed contents of organic acids and free sugars. Volatile compounds in figs were investigated using the solid-phase microextraction method of gas chromatography/mass spectrometry. For measurement of texture, elasticity increased up to stage 4 and decreased again. Cohesiveness and brittleness increased with maturation. Organic acids in figs were mainly composed of citric acid, malic acid, and tartaric acid in the final stage. Fructose and glucose were the major sugar components of figs. Fructose content decreased from stage 1 to stage 4 and then increased significantly. One hundred and nineteen volatile compounds were identified in figs, and classes were 14 acids, 15 alcohols, 23 aldehydes, 10 esters, 33 hydrocarbons, 11 ketones, four aromatics, six miscellaneous, and five terpenes. The dominant volatile components in figs were hexadecanoic acid, hexane, dodecanal, DL-limonene, 2-hexanal, nonanal, and 6-methyl-5-hepten-2-one.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1570-1576
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• 1999

Quality characteristics of 3 kinds of kochujang were investigated during 6 months of fermentation in order to improve the quality of industrial kochujang to that of traditional one. Three different kinds of kochujang were prepared using Aspergillus oryzae, Aspergillus oryzae plus Bacillus licheniformis and Aspergillus oryzae, Bacillus licheniformis plus Saccharomyces rouxii. Kochujang prepared with all three microorganisms contained lesser amounts of free sugar than the other preparations and glucose was the most abundant free sugar found. Ethanol was the most abundant amount among alcohols in kochujang. Kochujang prepared with A. oryzae, B. licheniformis plus S. rouxii has more amino nitrogen content than that prepared with A. oryzae only. Capsaicin contents of kochujang decreased slightly in all three kochujang, but there was no significant differences. The results of sensory evaluation showed statistically significant difference among three samples and panel members preferred the taste and flavor of kochujang prepared with all three microorganisms to those of the other samples.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.6
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• pp.609-628
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• 2015

Thie study presents the biomass-derived jet (bio-jet) fuel production technologies for greenhouse gas (GHG) reduction in aviation sector. The aviation sector is responsible for the 2% of the world anthropogenic $CO_2$ emissions and the 10% of the fuel consumption: airlines' costs for fuel reach 30% of operating costs. In addition, the aviation traffic is expected to double within 15 years from 2012, while fuel consumption and $CO_2$ emissions should double in 25 years. Biojet fuels have been claimed to be one of the most promising and strategic solutions to mitigate aviation emissions. This jet fuel, additionally, must meet ASTM International specifications and potentially be a100% drop-in replacement for current petroleum jet fuel. In this study, the current technologies for producing renewable jet fuels, categorized by alcohols-to-jet, oil-to-jet, syngas-to-jet, and sugar-to-jet pathways are reviewed for process, economic analysis and life cycle assessment (LCA) on conversion pathways to bio-jet fuel.

• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1121-1127
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• 2010

This study was performed to investigate the effects of adding a dual starter on the chemical and sensory characteristics of red wine made of Campbell Early grape. The yeast starter, Saccharomyces cerevisiae, and lactic acid bacteria (LAB) starter, Oenococcus oeni, were used for inoculation in the winemaking process for alcoholic fermentation and malolactic fermentation (MLF), respectively. After 200 days of incubation, the chemical compositions of yeast/LAB-added wine (YL-wine) were compared with those of no-starter-added wine (control) and yeast-added wine (Y-wine). The results show that no significant differences were observed in pH, total sugar, and alcohol content among the wine samples, but the malic acid content in YL-wine was significantly reduced, and various esters and higher alcohols were synthesized. The sensory test revealed that the addition of dual starters resulted in improved overall acceptability in wine. This study emphasizes the importance of O. oeni in addition to yeast in making Campbell Early wine.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.405-412
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• 1991

The enzymes were immobilized by treating the microbial cells in 0.05% chitosan and 0.28% glutaraldehyde solution. The activity of immobilized cell was about 535 IGIC/g. Glucose isomerase was purified by 6.5 times after homogenization using 60% $(NH_4)_2S0_4$ fractionation, DEAE-cellulose and Sephadex G-150 gel filtration. The molecular weight of enzyme was about 140,000 when it was measured by HPLC and the purified enzyme had only one band by electrophoresis. It showed good enzyme activity at pH 7.5 and $75^{\circ}C$. The optimum conditions for enzyme reactions were shifted to pH 7.0 and $80^{\circ}C$ when the enzyme was immobilized. The enzyme reaction was activated by the addition of 5~10 mM magnesium ion and the thermostability was improved by the addition of 0.25 mM cobalt ion. The enzyme activity was competitively inhibited by sugar alcohols.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.217-226
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• 2015

Metabolite profiles of seven commercial vinegars and two traditional vinegars were performed by gas chromatography time-of-flight mass spectrometry with multivariate statistical analysis. During alcohol fermentation, yeast, nuruk, and koji were used as sugars for nutrients and as fermentation substrates. Commercial and traditional vinegars were significantly separated in the principal component analysis and orthogonal partial least square discriminant analysis. Six sugars and sugar alcohols, three organic acids, and two other components were selected as different metabolites. Target analysis by ultra-performance liquid chromatography quadruple-time-of-flight mass spectrometry and liquid chromatography-ion trap-mass spectrometry/mass spectrometry were used to detect several metabolites having antioxidant activity, such as cyanidin-3-xylosylrutinoside, cyanidin-3-rutinoside, and quercetin, which were mainly detected in Rural Korean Black raspberry vinegar (RKB). These metabolites contributed to the highest antioxidant activity measured in RKB among the nine vinegars. This study revealed that MS-based metabolite profiling was useful in helping to understand the metabolite differences between commercial and traditional vinegars and to evaluate the association between active compounds of vinegar and antioxidant activity.

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1523-1531
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• 2012

The metabolite profile of meju during fermentation was analyzed using mass spectrometry techniques, including GC-MS and LC-MS, and the bacterial diversity was characterized. The relative proportions of bacterial strains indicated that lactic acid bacteria, such as Enterococcus faecium and Leuconostoc lactis, were the dominant species. In partial least-squares discriminate analysis (PLS-DA), the componential changes, which depended on fermentation, proceeded gradually in both the GC-MS and LC-MS data sets. During fermentation, lactic acid, amino acids, monosaccharides, sugar alcohols, and isoflavonoid aglycones (daidzein and genistein) increased, whereas citric acid, glucosides, and disaccharides decreased. MS-based metabolite profiling and bacterial diversity characterization of meju demonstrated the changes in metabolites according to the fermentation period and provided a better understanding of the correlation between metabolites and bacterial diversity.

• Journal of the East Asian Society of Dietary Life
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• v.6 no.2
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• pp.221-227
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• 1996

This study was performed to analyze general components such as, organic acids, alcohols and minerals In persimmon vinegar made with quick fermented using deteriorated sweet persimmon and four commercial vinegars (rice vinegar, apple vinegar, brewed vinegar, traditional persimmon vinegar) purchased In local markets for quality evaluation. The pH and total acidity of all vinegars were in the range of 2.02-3.02 and 4.62-9.78%, respectively The pH of quick fermented persimmon vinegar (A) was relatively higher than that of others. Acidity was the highest in brewed vinegar. Total sugar content was in the range of 0.45-6.43%. These contents were high In were high In traditional persimmon vinegar wherase low in brewed vinegar. Total nitrogen and amino-nitrogen were in the range of 0.025-0.046% and 0.015-0.029%. Organic acids were identified as acetic acid, citric acid, tartaric acid malic acid, succinic acid, formic acid and oxalic acid. While major minerals of all vinegars were Mg, Ca, and Na, minor minerals were Zn, Cu, Mn and Fe.

• Journal of Oral Medicine and Pain
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• v.41 no.4
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• pp.155-160
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• 2016

Purpose: It has been reported that xylitol and sorbitol affect antifungal activities by enhancing antimicrobial activities of other substances. The purpose of this study was to investigate the direct candidacidal activities of xylitol and sorbitol at a wide range of concentration. Methods: Xylitol and sorbitol solubilized with simulated salivary buffer at a range of $0.8{\mu}M$ to 1.05 M were used. Candida albicans strains, ATCC strains 10231, 11006, and 18804 were used for the candidacidal assay. The candidacidal activities of xylitol and sorbitol were determined by comparing the numbers of colony forming units between in the presence and absence of xylitol or sorbitol and calculating the percent loss of cell viability. Results: There were some differences in the candidacidal activities according to the types of sugar alcohols and C. albicans strains. The candidacidal activity of more than 10% was observed when a final concentration of 32.9 mM in xylitol or sorbitol was maintained and that of about 20% was observed when a final concentration of 131 mM was maintained. Even at a high concentration of 1.05 M, the candidacidal activity of xylitol or sorbitol was about 20%. Conclusions: Xylitol and sorbitol at the concentrations used in commercial oral health care products had some levels of candidacidal activities.