• Food Science and Preservation
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• v.21 no.4
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• pp.473-482
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• 2014

Changes in quality of mushroom during storage are severe problem that reduce the shelf life of harvested mushrooms. This study investigates the effect of oriental melon peel extracts on maintenance of the quality of mushrooms (Agaricus bisporus). Mushrooms were dipped in solutions (distilled water, DW; 0.1% oriental melon peel extract, OMP; 0.1% ascorbic acid, AA; and OMP+AA) for 3 minutes. After the dipped mushrooms were air-dried at room temperature, they were packaged in a polypropylene (PP) films and stored at $4^{\circ}C$ and $15^{\circ}C$. The changes in the quality of mushrooms were measured in terms of their color, gas composition, firmness, and sensory evaluation during storage at $4^{\circ}C$ and $15^{\circ}C$. The antioxidant and anti-browning activities of oriental melon peel extract were measured with respect to their total polyphenol contents, total flavonoid contents, DPPH, ABTS radical scavenging, copper chelating activity and PPO inhibition activity. The samples that were dipped in all the solutions did not show significant differences in firmness and gas exchange during their storage at $4^{\circ}C$ and $15^{\circ}C$. At both storage temperatures, the OMP solution samples showed highest L value and lowest delta E value. The sensory evaluation showed that during the storage period, the overall acceptability of mushrooms treated with the OMP and OMP+AA solutions was higher than that of the untreated mushrooms. The total polyphenol and flavonoid contents of oriental melon peel extract were $4.81mg\;GAE{\cdot}g^{-1}$ and $1.18mg\;QE{\cdot}g^{-1}$, respectively. The DPPH, ABTS radical scavenging activity, copper chelating activity and PPO inhibition activity of the oriental melon peel extract lower than ascorbic acid. All these results suggest that oriental melon peel extract can be used as a natural browning inhibitor.

• Membrane Journal
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• v.16 no.1
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• pp.16-24
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• 2006

We report on the preparation and characterization of sulfonated polymer membranes containing perfluorocyclobutane (PFCB) units and fluorene units. The polymers were prepared through three synthetic steps, that is, the synthesis of a trifluorovinylether-terminated monomer, its thermal polymerization, and post-sulfonation using chlorosulfonic acid. A series of sulfonated polymers with different ion exchange capacity (IEC) were prepared by changing the content of chlorosulfonic acid during the post-sulfonation reaction. All the synthesized compounds were characterized by FT-IR, $^{1}H-NMR,\;^{19}F-NMR$, and Mass spectroscopy. As the content of chlorosulfonic acid increased, the SD, IEC, water uptake, and ion conductivity of the sulfonated polymer membranes increased. The sulfonated polymer 4 showed higher values of ion conductivity than the Nafion-$115^{\circledR}$ in a wide range of temperatures ($25{\sim}80^{\circ}C$).

• Membrane Journal
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• v.21 no.1
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• pp.30-38
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• 2011

Composite membranes based on sulfonated poly(aryl ether) sulfone (SPAES) with different sulfated zirconia nanoparticles ($s-ZrO_2$) ratio are synthesized and investigated for the improvement of the hydration and the proton conductivity at high temperature and no humidification for fuel cell applications. X-ray diffraction technique is employed to characterize the structure and the size of $s-ZrO_2$ nanoparticles. The sulfation effect of $s-ZrO_2$ nanoparticles is verified by FT-IR analysis. The properties of the SPAES composite membranes with the various $s-ZrO_2$ ratio are evaluated by ion exchange capacity and water content. The proton conductivities of the composite membranes are estimated at room temperature with full hydration and at the various high temperature without external humidification. The composite membrane with 5 wt% $s-ZrO_2$ shows the highest proton conductivity. The proton conductivities are $0.9292\;S\;cm^{-1}$ at room temperature with full hydration and $0.0018\;S\;cm^{-1}$ at $120^{\circ}C$ without external humidification, respectively.

• Membrane Journal
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• v.21 no.1
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• pp.1-12
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• 2011

Partially fluorinated poly(arylene ether sulfone) block ionomer membranes with different branch degree for fuel cell applications were investigated. A sulfonable monomer, a non-sulfonable monomer and a trifunctional branching agent were synthesized and the sulfonable monomer was oligomerized to obtain block structures. The oligomer was then further polymerized with the non-sulfonable monomer and the branching agent. The mole ratio of oligomer : non-sulfonable monomer was fixed at 4:6 and the content of the branching agent was varied from 0 to 2 mol% (BBC-40Bx). Post-sulfonation of BBC-40Bx was carried out using chlorosulfonic acid (CSA) (SBBC-40Bx). All the synthesized compounds were characterized by $^1H$-NMR, $^{19}F$-NMR and FT-IR. It was confirmed that the ion exchange capacity (IEC), water uptake and ion conductivity of SBBC-40Bx increased with the increment of branching agent content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.527-533
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• 2002

In the screening of Korean traditional tea sources for the cellular lysosomal enzyme activity of peritoneal macrophage from mice, CT-0, a cold-water extract from Carthamus tinctorius L., showed the highest macro-phage-stimulating activity. CT-1-IIa-2-1, a purified macrophage-stimulation polysaccharide was obtained by a series of purification steps such as anion exchage chromatography with DEAE-Toyopearl 650M, gel permeation chromatography with Sepharose CL-6B, Sephacryl S-200, and HPLC with Superdex G-75. The molecular weight of homogeneous purified polysaccharide was estimated about 68 kDa. CT-1-IIa-2-1 consisted of xylose 27.44%, arabinose 16.14%, mannose 15.92% and glucose 14.47%. To measure acute toxicity, dose of 50, 100, 500, and 1000 mg/kg were intraperitoneally injected to ICR mice. The LD$\_$50/ was about 397 mg/kg.

• The Korean Journal of Mycology
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• v.23 no.4 s.75
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• pp.332-339
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• 1995

Water-soluble polysaccharide (FCW) was extracted from the fruiting body of Fomitella fraxinea with neutral sodium chloride solution. The polysaccharide was further fractionated into FCW-I and FCW-II by ion exchange chromatography. The FCW-I and FCW-II were then purified by gel permeation chromatography and named as FCW-Ia and FCW-IIa, respectively. FCW-IIa showed relatively strong immuno-stimulating activity but FCW-Ia did not. By analyses of HPLC and GPC, FCW-Ia and FCW-IIa were identified to be homogeneous and their molecular weights were estimated to be about 15,000 and 8,700, respectively. FCW-Ia consisted of fucose, galactose, and mannose as main sugars and their molar ratio was 19.5 : 63.2 : 25.0. Protein was not detected in FCW-Ia. However, FCW-IIa was composed of glucose, galactose, and mannose at a molar ratio of 1.0 : 0.3 : 0.4 and contained 0.4% protein with a higher amount of glutamic acid. A small amount of uronic acid was detected in both FCW-Ia and FCW-IIa.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.243-249
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• 2005

Esterification of lactic acid with alcohols catalyzed by Amberlyst-type ion exchange resins and sulfuric acid was carried out in a batch reactor with total /or partial recycle of distilled condensates, respectively. The esterification of lactic acid in the total-recycling reactor (n-butanol/lactic acid = 4, $100^{\circ}C$) was promoted by decreasing the residual water and increasing the mole ratio of n-butanol/lactic acid. Also, it was confirmed that methanol with simple structure and tert-butanol with superior substitution reactivity were more effective in increasing the conversion of esterification reaction, compared to ethanol, n-butanol, and iso-butanol. In a partial-recycling reactor (n-butanol/ammonium lactate = 4, $115^{\circ}C$), the conversion of ammonium lactate into butyl lactate with 1.0 wt% Amberyst-type resins was higher in comparison to that with 0.2 mol $H_2SO_4$ (per 1.0 mol ammonium lactate). The esterification was gradually occurred during the initial stage of reaction in the presence of solid catalyst, whereas the initial addition of $H_2SO_4$ did not affect the initial rate of esterification reaction because of ammonium sulfate formation by the neutralizing reaction of ammonium lactate with sulfuric acid.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.998-1001
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• 2002

Micro-LC method for the quantitative determination of hydrogen peroxide in foods has been established. This method was carried out on cation-exchange resin gel column using distilled water as mobile phase with 50 mM sodium sulfate as electrolyte. The detection was performed with an electrochemical detector (ECD) at 0.6 voltage. Under this analytical condition, the recovery rates of hydrogen peroxide in tomato and lemon were 98.3 and 97.4%, respectively. Among 28 food types, hydrogen peroxide concentrations were 0.6, 0.5, 1.9, 0.9, 0.5, 0.6, 0.9, 0.8, and 0.4 ppm in banana, peach, orange, strawberry, pepper, onion, cucumber, burdock, and egg plant, respectively, Whereas none was detected in remaing 19 samples.

• Journal of Soil and Groundwater Environment
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• v.19 no.4
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• pp.62-69
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• 2014

In the results of monitoring nitrate concentration in more than 8,000 groundwater wells around agro-livestock, the average and maximum nitrate concentration was 9.4 mg/L and 101.2 mg/L, respectively. Since about 31% of the monitoring wells was exceed the quality standard for drinking water, nitrate control such as remediation or source regulation is required to conserve safe-groundwater in South Korea. Typical nitrate-treatment technologies include ion exchange, reverse osmosis, and biological denitrification. Among the treatment methods, biological denitrification by indigenous microorganism has environmental and economic advantages for the complete elimination of nitrate because of lower operating costs compared to other methods. Major mechanism of the process is microbial reduction of nitrate to nitrite and nitrogen gas. Three functional genes (nosZ, nirK, nirS) that encode for the enzyme involved in the pathway. In this work, we tried to develop simple process to determine possibility of natural denitrification reaction by monitoring the functional gene. For the work, the functional genes in nitrate-contaminated groundwater were monitored by using PCR with specific target primers. In the result, functional genes (nosZ and nirK) encoding denitrification enzymes were detected in the groundwater samples. This method can help to determine the possibility of natural-nitrate degradation in target groundwater wells without multiplex experimental process. In addition, for field-remediation application we selected nitrate-contaminated site where 200~600 mg/L of nitrate is continuously detected. To determine the possibility of nitrate-degradation by stimulated-natural attenuation, groundwater was sampled in two different wells of the site and nitrate concentration of the samples was 300 mg/L and 616 mg/L, respectively. Fumarate for different C/N ratio was added into microcosm bottles containing the groundwater to examine denitrification rate depending on carbon concentration. In the result, once 1.5 times more than amount of fumarate stoichiometry required was added, the 616 mg/L of nitrate and 300 mg/L of nitrate were completely degraded in 8 days and 30 days. The nitrite, byproduct of denitrification process, was also completely degraded during the experimental period.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.67-71
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• 1998

This study was carried out to granulate artificial zeolite powder that remove ammonium nitrogen and phosphorous simultaneously in wastewater treatment. Optimum water content was required for 30 percent volume to granulate artificial zeolite with 1.7mm diameter and 1~2cm length using granulator. Portland cement could remove much $NH_4{^+}$ and $PO_4{^{3-}}$ from the wastewater than other binding materials. Mixed 33, 25. 20. 16 percent of portland cement to artificial zeolite powder(v/v), cation exchange capacity of the granulars were 66.5, 81.4, 126.8, $151.2cmol^+kg^{-1}$ and hardness of that were 176.1, 24.4, 4.1, $0.4kg\;cm^{-2}$, respectively. Content of portland cement in the granular were related with removal of $PO_4{^{3-}}$ positively and that of $NH_4{^+}$ negatively. Shaked 1g of the granulars that made of portland cement 33 percent with 40ml synthetic wastewater containing $NH_4{^+}$ $1545mgl^{-1}$ and $PO_4{^{3-}}$ $417mgl^{-1}$, 99.4 percent of $NH_4{^+}$ and 90.3 percent of $PO_4{^{3-}}$ were removed simultaneously after 48 hours shaking. The longer shaking, the more $NH_4{^+}$ and $PO_4{^{3-}}$were removed. The artificial zeolite granular had both micropore and macropore that could be useful in the wastewater purification.