• Food Science and Biotechnology
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• v.18 no.3
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• pp.717-723
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• 2009

Thermal degradation characteristics of sucrose was investigated. A 20% sucrose solution was heated to temperatures of $110-150^{\circ}C$ for 1-5 hr. Chromaticity, pH, organic acids, 5-hydroxymethylfurfural (HMF), free sugars, electron donating ability (EDA), and ascorbic acid equivalent antioxidant capacity (AEAC) of the heated sucrose solutions were evaluated. With increasing temperatures and times, the L-, a-, and b-values decreased; however, total color difference (${\Delta}E_{ab}$) increased. The pH and sucrose contents decreased, and fructose and glucose contents increased with increasing heating temperature and time. Organic acids, such as formic acid, lactic acid, and levulinic acid, and HMF contents increased with increasing heating temperatures and times. EDA (%) and the AEAC of the heated sucrose solutions increased with increasing heating temperature and time. The heated sucrose solution was more effective than unheated sucrose solution, having higher EDA (90 fold), and AEAC (13 fold).

• Food Science and Preservation
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• v.10 no.4
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• pp.488-492
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• 2003

This study was analyzed to the components of leaf teas produced by manufature methods for which estimated food and nutritional values of Lindera obtusiloba loaves growed in Korea and had unique taste and aroma. There were identified to four kinds of free sugars in Lindera obtusiloba leaf teas and its content was the highest in the roasted tea among others. The contents of glutamic acid, aspartic acid, asparagine, and glycine were remarkably higher than other amino acids. The contentsof free amino acid in the leased tea and the androasted tea after steaming wase. 6 mg/100g had 101.5 mg/100g, respectively,had especially higher than in the others. Among the amino acid derivativer, phosphoserine, ${\alpha}$-aminobutyric acid, ${\beta}$-aminobutvic acid, and anserine contents were especially higher than others, but were not significantly difference by the manufacturing process. The volatile organic acids were composed acetic, propionic and butyric acid, and the nenvolatility organic acid were composed citric, oxalic, levulinic glutaric, lactic and pyroglutamic acid.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.512-515
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• 2000

In this study, ${\delta}-aminolevulinic$ acid, porphobilinogen, glycine and levulinic acid were succesfully separated by capillary electrophoresis(CE). We established the separative conditions of the mixture containing four components by CE. The borate buffered solution was used for CE electrolyte, and its pH was adjusted to $9.25{\sim}9.42$. Under constant current or constant voltage, higher concentraion of borate produced better resolution of four components, but adversely affected migration rates , resulting in longer analysis time. While migration time was faster with increase in applied voltage, but adversely affected resolution. Each component was separated well in borate buffer of 30mM at the applied voltage of 20kV.

• Journal of Microbiology and Biotechnology
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• v.30 no.6
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• pp.930-936
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• 2020

The red seaweed Gracilaria verrucosa has been used for the production of bioethanol. Pretreatment for monosaccharide production was carried out with 12% (w/v) G. verrucosa slurry and 500 mM HNO₃ at 121℃ for 90 min. Enzymatic hydrolysis was performed with a mixture of commercial enzymes (Cellic C-Tec 2 and Celluclast 1.5 L; 16 U/ml) at 50℃ and 150 rpm for 48 h. G. verrucosa was composed of 66.9% carbohydrates. In this study, 61.0 g/L monosaccharides were obtained from 120.0 g dw/l G. verrucosa. The fermentation inhibitors such as hydroxymethylfurfural (HMF), levulinic acid, and formic acid were produced during pretreatment. Activated carbon was used to remove HMF. Wild-type and adaptively evolved Saccharomyces cerevisiae, Candida lusitaniae, and Kluyveromyces marxianus were used for fermentation to evaluate ethanol production.

• Journal of Plant Biology
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• v.36 no.3
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• pp.267-273
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• 1993

Promoters of the chlorophyll a/b bidning protein genes, cab1, and cab2, of Arabidopsis thaliana were studied for their functions in differential expression during greening of etiolated shoots. The etiolated shoots were derived from leaves of transgenic tobacco plants with the cab-CAT (chloramphenicol acetyltransferase) translational fusions, and CAT activity was measured to monitor the activities of the cab promoters. Cab1 promoter activity increased rapidly and showed saturation after about 24 hours of greening, but that of cab2 increased with about 2 day-lag period and showed saturation after 6 days. Cab1 promoter activity was more sensitive to levulinic acid (LA) compared with cab2 activity. Cab2 promoter activity was inhibited more sensitively by chloramphynicol (CAP) than by inhibitors of Chl formation. Cab1 promoter activity was, however, inhibited less sensitively by CAP than by LA. The treatment of abscisic acid (ABA) did not block Chl synthesis so significantly as LA treatment did, and cab2 promoter activity was much less sensitive to ABA compared with that of cab1. These results suggest that cab1 expression is strongly related with Chl formation, possibly with $\delta$-aminolevulinic acid accumulation, and cab2 expression is suppressed more by the blockage of translation of Chl a-apoproteins than by the blockage of Chl a accumulation.

• Environmental Analysis Health and Toxicology
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• v.4 no.3_4
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• pp.1-6
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• 1989

The effects of his ($\beta$-amino-ethyl-oxo) oxalate and bis ($\alpha$-amino-methyl-oxo) oxalate on the toxicity of lead acetate in rast were examined. Rats were given intraperitoneally at the dose of lead acetate 45 mg/kg. The exposure of lead acetate showed the 70% decrease of ALAD ($\delta$-amino levulinic acid dehydratase) activity in red blood cell. In vivo 122 mg/kg administration of bis ($\beta$-amino-ethyl-oxo) oxalate and bis ($\alpha$-amino-methyl-oxo) oxalate showed the 50% increase of ALAD activity, whereas 149 mg/kg administeration of Ca-EDTA had no effect. In vitro, the same results were obtained. Both compounds had hemolytic activity at concentrations higher than that required for showing the 50% ALAD activity increase in vivo.

• Journal of the Korean Society of Tobacco Science
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• v.16 no.2
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• pp.152-162
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• 1994

This study was designed to establish an analytical method for the properties of leaf tobacco smoke. Lyophilized TPM from leaf tobacco smoke was extracted with MeOH, dried under reduced pressure, and trimethyl-silylated(TMS). Gas chromatography of the material using SPB-5 column showed 120 quantifiable peaks. Among those, 26 compounds including a hydrocarbons, Neophytadiene. and Levulinic acid could be identified through GC-MS. Smoke properties of 5 manufacturing grades and 2 oriental cultivars of domestic and imported leaf tobacco including AB3O-1 were analyzed. For flue-cured tobacco, content of the compounds in the smoke was generally higher in American leaf tobacco except for glycerol compounds. For burley tobacco, domestic leaves were found to have much higher amount of smoke compound than imported leaves. Among oriental tobacco, Izmir contained slightly higher amount of smoke compounds than Basma. Key words : GC - profile. TPM. TMS. Leaf tobacco.

• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.48-54
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• 2016

In this study, biosugar production by the red-algae Eucheuma cottonii was investigated using dilute sulfuric acid-catalyzed hydrolysis and data analysis by response surface methodology. This approach yielded 25.8 g/l total reducing sugar under the conditions of $160.1^{\circ}C$, 1% (v/v) sulfuric acid, and 13.1 min. The sugar concentration showed a linear inverse correlation with the combined severity factor (CSF) of the reaction conditions. CSF was calculated as $log(t{\cdot}e{xp}[(T_H-T_R)/14.75])-pH$, where t is the coupling reaction time, $T_H$ is the target temperature, and $T_R$ is the reference temperature ($100^{\circ}C$). In addition, levulinic acid production showed a linear positive correlation with CSF. E. cottonii may represent a useful feedstock for sugar production in the field of bioenergy.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.219-224
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• 1998

The cyclic metabolism of poly(3-hydroxyhutyrate-co-3-hydroxyvalerate) synthesized from glucose by Alcaligenes sp. SH-69 in the presence or absence of new carbon substrate was investigated. In batch culture, the content and weight average molecular weight of the copolymer already stored in the cell decreased rapidly when there was no other carbon source available. After the depletion of carbon source, the amount of high molecular weight copolymer decreased more rapidly than that of low molecular weight copolymer, and as a result, average molecular weight distribution shifted to the lower value. The addition of a mixture of glucose and levulinic acid when the initial carbon substrate, glucose, was nearly depleted supported the continual increase in cell mass and the accumulation of poly(3HB-co-3HV) with high molar fraction of 3HV. However, solvent fractionation of the polymer with acetone revealed the degradation of pre-existing polyhydroxyalkanoale (PHA) in parallel with the synthesis of PHA from new carbon substrate. Even though PHAs obtained from each substrate alone were the copolymer of 3HB and 3HV, it was found that the polymer accumulated in the cells grown by sequential feeding was mainly physical mixture of two poly(3HB-co-3HV) copolymers containing different molar fractions of 3HV.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.293-300
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• 1999

Garlic from 4 main growing area was analyzed for the composition related to garlic flavor. Twenty-eight volatile compounds in garlic were separated by GC and twenty five were identified by GC/MS. Total peak area was high in garlic from $S\u{o}san$, and low from $Hampy\u{o}ng$. However, no significant difference was found in total peak area of sulfur compounds for garlic from Namhae, $S\u{o}san$, and $Uis\u{o}ng$. The results of free sugars analysis showed that relatively large amount of 1-kestose, 1-nystose, and 1-F-fructosyl nystose known as fructooligosaccharide were found in garlic in addition to glucose, fructose, and sucrose. Garlic from $S\u{o}san$ contained high amount of 1-nystose and 1-F- fructosyl nystose. Total free amino acid content in garlic was in a range of $2036.1{\sim}2704.0mg%$, and it was higher in garlic from $S\u{o}san$ and $Uis\u{o}ng$. Lactic acid, pyruvic acid, oxalic acid, malonic acid, fumaric acid, levunic acid, succinic acid, malic acid, citric acid and pyroglutamic acid were found in garlic. Total organic acid content in garlic was $1905.7{\sim}2359.2mg$, and garlic from $Hampy\u{o}ng$ had relatively low organic acid contents.