• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.2
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• pp.253-258
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• 2011

To increase utilization of Korean sweet persimmon, white breads containing sweet persimmon were prepared and those characterizations were evaluated. WB (white bread without persimmon), FPB (white bread containing 30% (w/w) persimmon flesh), and WPB (white bread containing 30% (w/w) whole persimmon) were prepared by straight dough method. Specific volumes of WB, FPB, and WPB were 3.51, 2.99 and 3.21 $cm^3$/g, respectively. Loss of bread of WB, FPB, and WPB were 9.81, 7.78, and 8.86%. With addition of sweet persimmon in bread, the lightness (L) was decreased, and the redness (a) and the yellowness (b) were increased. DPPH radical scavenging activity, one of antioxidant activity, of WB, FPB, WPB at concentration of 10 mg/mL was $12.39{\pm}0.135$, $14.57{\pm}0.01$, and $19.57{\pm}0.44%$, respectively. Total phenolic contents of WB, FPB and WPB were $177.05{\pm}5.52$, $185.26{\pm}0.79$, and $216.24{\pm}5.47$ mg GAE/g. Hardness of WB were 175.33 Dyne/$cm^3$, and the value was decreased in FPB and WPB. In sensory test, FPB acquired relatively high points in texture, flavor, taste, and overall acceptance.

• Journal of Soil and Groundwater Environment
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• v.13 no.5
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• pp.8-19
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• 2008

The physicochemical properties of soils having high uranium content, located around Duckpyungri in Korea, were investigated and the lab scale soil washing experiments to remove uranium from the soil were preformed with several washing solutions and on various washing conditions. SPLP (Synthetic Precipitation Leaching Procedure), TCLP (Toxicity Characteristic Leaching Procedure), and SEP (Sequential Extraction Procedure) for the soil were conducted and the uranium concentration of the extracted solution in SPLP was higher than Drinking Water Limit of USEPA (30 ${\mu}g$/L), suggesting that the continuous dissolution of uranium from soil by the weak acid rain may generate the environmental pollution around the research area. For the soil washing experiments, the uranium removal efficiency of pH 1 solution for S2 soil was about 80 %, but dramatically decreased as pH of solution was > 2, suggesting that strong acidic solutions are available to remove uranium from the soil. For solutions with 0.1M of HCl and 0.05 M of ${H_2}{SO_4}$, their removal efficiencies at 1 : 1 of soil vs. washing solution ratio were higher than 70%, but the removal efficiencies of acetic acid, and EDTA were below 30%. At 1 : 3 of soil vs. solution, the uranium removal efficiencies of 0.1M HCl, 0.05 M ${H_2}{SO_4}$, and 0.5M citric acid solution increased to 88%, 100%, and 61% respectively. On appropriate washing conditions for S2 soil such as 1 : 3 ratio for the soil vs. solution ratio, 30 minute for washing time, and 2 times continuous washing, TOC (Total Organic Contents) and CEC (Cation Exchange Capacity) for S2 soil were measured before/after soil washing and their XRD (X-Ray Diffraction) and XRF (X-Ray Fluorescence) results were also compared to investigate the change of soil properties after soil washing. TOC and CEC decreased by 55% and 66%, compared to those initial values of S2 soil, suggesting that the soil reclaimant may need to improve the washed soils for the cultivated plants. Results of XRF and XRD showed that the structural change of soil after soil washing was insignificant and the washed soil will be partially used for the further purpose.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.296-301
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• 2009

In order to investigate the effect of different yeasts (La Parisienne (LP), Y18-2, Y54-3, Y90-2, Y90-9 and Y272-7) from nuruks on the quality of Glutinous rice wines, physicochemical properties and volatile flavor components were evaluated. Glutinous rice wines prepared with different yeasts were analyzed for ethanol, pH, total acid, amino acid, soluble solid, coloring degree, UV absorbance, reducing sugar, organic acid, free sugar and volatile compounds. After fermentation for 17 days, the ethanol contents ranged from 13.40 to 14.50%, while the total acid levels were from 0.33 to 0.44%. The amino acid contents in six samples ranged from 0.13 to 0.18%, while soluble solid contents ranged from 12.1 to $14.7^{\circ}Bx$. The glutinous rice wine prepared with LP showed the highest level of coloring degree, soluble solid and reducing sugar among six samples. Organic acid contents of the glutinous rice wine prepared with LP had the highest levels of lactic acid and acetic acid, while the glutinous rice wine prepared with Y90-9 had the highest level of succinic acid. In all glutinous rice wines tested, the most abundant free sugars were glucose followed by maltose. Volatile flavor components in the glutinous rice wines were identified by using GC-MSD. Nineteen esters, ten alcohols, eight acids, one aldehyde and one miscellaneous compound were identified in the glutinous rice wines. Using relative peak area, it was found that other than ethyl alcohol, hexadecanoic acid ethyl ester was the major component, predominantly found in the range of 2.73-10.41%. Phenylethyl alcohol, isoamyl alcohol, ethyl oleate, ethyl linoleate and tetradecanoic acid ethyl ester were some of the major volatile components present through the fermentation, respectively. Overall, it was shown that different yeast strains from nuruks greatly affected chemical and volatile characteristics of the glutinous rice wines.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.275-281
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• 2004

Our previous research has demonstrated that the bacterium, Pseudomonas sp. NFQ-l capable of utilizing quin­oline (2,3-benzopyridine) as the sole source of carbon, nitrogen, and energy was isolated and characterized [Yoon et ai. (2003) Kor. J. Biotechnol. Bioeng. 18(3):174-179]. In this study, we have found that Pseudomonas sp. NFQ-l could degrade quinoline as well as benzoate, and extended this work to characterize the catechol 1,2­dioxygenase (C1,2O) purified from the bacterium cultured in benzoate media. Initially, C1,2O has been purified by ammonium sulfate precipitation, gel permeation chromatography, and Source 15Q. After Source 15Q, puri­fication fold was increased to approximately 14.21 unit/mg. Molecular weight of C1,2O was about 33 kDa. Physicochemical characteristics (e.g., substrate specificity, Km, Vmax, pH, temperature and effect of inhibitors) of purified C1,2O were examined. C1,2O demonstrated the activity for catechol, 4-methylcatechol and 3-meth­ylcatechol as a substrate, respectively. The Km and Vmax value of C1,2O for catechol was 38.54 ${\mu}M$ and $25.10\;{\mu}mol{\cdot}min^{-1}{\cdot}mg^{-1}.$ The optimal temperature of C1,2O was $30^{\circ}C$ and the optimal pH was approximately 8.5. Metal ions such as $Ag^+,\;Hg^+,\;Ca^{2+},\;and\;Cu^{2+}$ show the inhibitory effect on the activity of C1,2O. N-terminal amino sequence of C1,2O was analyzed as ^1TVKISQSASIQKFFEEA^{17}.$ In this work, we found that the amino acid sequence of NFQ-l showed the sequence homology of 82, 71, 59 and $53\%$ compared with C1,2O from Pseudomonas aeruginosa PA0l, Pseudomonas arvilla C-1., P. putida KT2440 and Pseudomonas sp. CA10, respectively.

• Journal of Life Science
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• v.27 no.2
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• pp.202-210
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• 2017

As an effort to find a potential biopreservative, we isolated bacterial strains producing bacteriocin from fermented foods. A strain was finally selected and characteristics of the bacteriocin were investigated. The selected strain was identified as Bacillus subtilis E9-1 based on the 16S rRNA gene analysis. The culture supernatant of B. subtilis E9-1 showed antimicrobial activity against Gram-positive bacteria. Subtilisin A, ${\alpha}$-chymotrypsin, trypsin and proteinase K inactivated the antimicrobial activity, which means its proteinaceous nature, a bacteriocin. The bacteriocin activity was fully retained at the pH range from 2.0 to 8.0 and stable at up to $100^{\circ}C$ for 60 min. Solvents such as ethanol, isopropanol and methanol had no effect on the antimicrobial activity at the concentration of 100% but acetone and acetonitrile reduced the activity at up to 100% concentration. Cell growth of four indicator strains was dramatically decreased in dose-dependent manner. Listeria monocytogenes was the most sensitive, but Enterococcus faecium was the most resistant. Bacillus cereus and Staphylococcus aureus showed the medium sensitivity. The bacteriocin showed its antimicrobial activity against B. cereus and L. monocytogenes via bactericidal action. The number of viable cells of L. monocytogenes started to reduce after addition of bacteriocin to the minced beef. The bacteriocin was purified through acetone concentration, gel filtration chromatography and RP-HPLC. The whole purification step led to a 6.82 fold increase in the specific activity and 6% yield of bacteriocin activity. The molecular weight of the purified bacteriocin was determined to be 3.3 kDa by MALDI-TOF/TOF mass spectrometry.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.238-245
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• 1999

Antioxidative effects of the water or ethanol extracts from Rhus verniciflua Stokes (RVS) were measured by protection against hydroxyl radicals in mouse brain tissue culture. In the water extracts from RVS, cell viabilities were estimated 60.0, 66.0, 72.0, 84.0 and 90.0% at addition of 1, 2, 4, 7 and $10{\mu}L$, respectively, compared with GO (20 mU/mL) alone. The cell viability in the ethanol extracts was similarly with water extracts. In the antitumor effects, the results showed that percentages of the HeLa cell death were approximately 24% for 12 hrs, 57% for 48 hrs at addition of 10%/well ethanol extracts respectively. To know inhibition of tumor growth, in vivo, mice (BALB/c) were inoculated with 0.25 mL CT-26 $(1{\times}10^6\;cells/mL)$ subcutaneously. After the generation of tumor, the results of RVS extracts (ethanol, water) injection showed generally that the tumor size in BALB/c was reduced. For physicochemical characterization of the RVS extracts, purified substances of water or ethanol extracts were analized with SDS-PAGE and ICP spectrometer. In electrophoresis, gel showed 2 bands (210, 230 KDa). The results of ICP verified that RVS extracts contain $Cu^{2+}$ in both samples. Conclusively, this substance might be a laccase which has a biological effective function, as a natural bioactive substance.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.872-879
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• 2010

Layered copper hydroxides [LCHs, $Cu_2(OH)_3{\cdot}NO_3$] has the agricultural potentials as a fungicide because of its high crystallinity, excellent anion exchange capacity, and its regular layered particle size. The study, for the first time, has synthesized LCHs in highly concentrated solution and evaluated its physicochemical properties including the crystallinity and suspension stability. Optimal synthetic condition of LCHs was determined by crystallinity and stability of suspension as follow; 1) concentrations of $Cu(NO_3)_2$ and NaOH solutions were 3.0 M respectively, 2) reaction temperature and solution pH were $25^{\circ}C$ and 6.0, respectively, and 3) aging time after reaction was 2hr. Crystallinity of LCHs enhanced with increase in pH up to 9.0. Whereas, stability of suspension was decrease by increase in crystal size. Especially, increase in reaction temperature decreased stability of suspension. XRD patterns and SEM images exhibited that LCHs had regular layered particle size with 0.2~0.8 ${\mu}m$ and high crystallinity in optimal synthetic condition. The particle size was increased with increase in reaction temperature and pH. These results showed that LCHs synthesized in highly concentrated solution exhibited high stability of suspension as well as high crystallinity suitable to their potential as a fungicide.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.382-390
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• 2021

In this study, solubilized yuzu pulp powder (EYP) was produced using enzyme treated yuzu pulp powder (YP) and used to manufacture yuzu granules (0-20% EYP content). The physicochemical, product stability, and functional properties of Yuzu granules were compared among five enzyme treatments. Among the five treatments, CL had the highest YP solubilization yield (48.68%). Microstructural observation of EYP using FE-SEM revealed that its surface became irregular and porous after enzymatic treatment. Compared to YP, EYP had 2 times lower insoluble dietary fibers and 3 times lower hemicellulose and cellulose content. Among the yuzu granules, IV (yuzu granules with 15% EYP) had an excellent water and oil holding capacity and flowability. IV granule had the highest narirutin and hesperidin content of 3.4 mg and 2.2 mg/g DW, respectively and the highest antioxidant (68.4%) and tyrosinase inhibitory activities (82.5%). Therefore, EYP or granule with EYP can be used as a functional component in food industry or pharmaceutical field.