• 한국식품과학회지
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• 제23권4호
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• pp.517-519
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• 1991

글루코오스 산화효소와 수피옥사이드 디스뮤타제가 유지의 산화를 억제할 수 있는지 여부를 알아보기 위하여 이들 효소와 기질을 어유에 직접 용해시키고 시료를 vial에 담아 저장하면서 상부공간의 산소함량과 어유의 과산화물값의 변화를 측정하였다. GO 첨가구의 경우 산소의 감소속도는 대조구와 비슷하였으나 과산화물값은 훨씬 낮은 수준이었다. 이러한 결과는 산소의 일부가 GO의 기질로 소모되어 유지의 산화에 공급된 산소가 제한되었기 때문으로 풀이된다. SOD를 첨가하였을 때에도 유지의 산화가 억제되었는데 이는 SOD가 반응성이큰 일중항 산소를 기저상태의 산소로 전환시킬 수 있었기 때문으로 생각된다.

• 한국축산식품학회지
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• 제38권5호
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• pp.889-900
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• 2018

Characterization and utilization of the bioactive compounds from natural resources is one of the most concerns to maintain quality properties of foods, especially to prevent the oxidation of lipids in meat products. Phytochemical components and antioxidant activities of Cudrania tricuspidata (CT) leaves extracted using various solvents and their effects on physicochemical properties of pork patties during refrigerated storage were measured. The combined solvents of 80% ethanol, 80% methanol and pure double-distilled (dd)-water obtained the higher total phenolic compounds, flavonoids content, and antioxidant activities as compared to the pure solvent alone. Among the individual antioxidant components, catechin was the predominant polyphenol in CT leaves in all extracts. The addition of CT leaves extracts into pork patties showed high antioxidant activities since thiobarbituric acid-reactive substances (TBARS) values of added CT extracts were lower than those of the control (p<0.05). In conclusion, CT leaf phytochemical components displayed antioxidant activity that varied with the extract solvent used. CT extracts were superior to control in retarding lipid oxidation of pork patties, which was evident as reduced TBARS and peroxide values (POV).

• 동의생리병리학회지
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• 제27권2호
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• pp.189-195
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• 2013

This study was designed to analyze the effects of methanol extracts and solvent fractions of the young branch of Prunus persica on scavenging activity of ROS, RNS and inhibiting activity of oxidative modification in human LDL induced by copper ion or free radical generator. The scavenging capacities of the fractions on DPPH radical, superoxide radical, nitric oxide and peroxynitrite were exhibited the highest in ethylacetate fraction, followed by butanol fraction. In the copper-induced LDL oxidative modification system, the highest antioxidant activity was revealed in ethylacetate fraction, and butanol fraction exhibited a similar activity. However, solvent fractions of the young branch of Prunus persica showed a relatively low antioxidant activity in the AAPH-mediated LDL oxidation. In addition, ethylacetate and butanol fractions also inhibited the copper-mediated LDL oxidation in the REM assay, which was comparable to that of the positive controls, including EDTA, ascorbic acid and BHT. Futhermore, a content of total phenolics in these two fractions was higher than that of the other fractions. These results indicated that ethylacetate and butanol fractions of the young branch of Prunus persica were useful for the prevention of the free radical- or metal ion-induced oxidative damages.

• Journal of Microbiology and Biotechnology
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• 제16권3호
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• pp.469-474
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• 2006

Partial nitrification blocking of the oxidation of nitrite ($NO_{2}^{-}$) to nitrate ($NO_{3}^{-}$) has cost-efficient advantages such as lower oxygen and organics demand for nitrification and denitrification, respectively. A nitrifying membrane bioreactor of submerged type was operated for the treatment of synthetic ammonium wastewater with the purpose of nitrite build-up without affecting the efficiency of ammonium oxidation. A high ammonium concentration (1,000 mg/l) was completely converted to nitrate at up to 2 kg $N/m^3$ day under sufficient aeration. The control of pH under sufficient aeration was not a reliable strategy to maintain stable nitrite build-up. When the dissolved oxygen concentration was kept at 0.2-0.4 mg/l by adjusting the aeration rate, about 70% of nitrite content was obtained with ammonium oxidation efficiency higher than 93%. The increase of suction pressure due to membrane fouling was not significant under lowered aerating environment over a 6-month period of operation. The composition of nitrifier community, including relative abundance of nitrite oxidizers in a nitrite-accumulating condition, was quantified by fluorescence in situ hybridization analysis.

• 한국수소및신에너지학회논문집
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• 제22권2호
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• pp.213-222
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• 2011

To check adaptability of low ash coal(hyper coal) to chemical looping combustion, reaction characteristics of two coals (Roto and Hyper coal) with two oxygen carriers (NiO/bentonite, OCN703-1100) have been investigated in a thermogravimetric analyzer. Hyper coal represented low combustion rate and high ignition temperature, high volatile content and high devolatilization rate, and therefore, showed worse oxygen transfer during successive 10 cycle reduction-oxidation test than Roto coal. Finally we selected Roto coal as the candidate coal for chemical looping combustion. For Roto coal, OCN703-1100 particle showed better oxygen transfer than NiO/bentonite particle. During 10 cycle reduction oxidation test, change of the extent of oxidation (Wo) was negligible and we could conclude that both oxygen carriers have sufficient regeneration ability.

• 한국분말재료학회지
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• 제12권3호
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• pp.225-230
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• 2005

In order to prevent the oxide formation on the surface of nano-size iron particles and thereby to improve the oxidation resistance, iron nanoparticles synthesized by a chemical vapor condensation method were directly soaked in hexadecanethiol solution to coat them with a polymer layer. Oxygen content in the polymer-coated iron nanoparticles was significantly lower than that in air-passivated particles possessing iron-core/oxide-shell structure. Accordingly, oxidation resistance of the polymer-coated particles at an elevated temperature below $130^{\circ}C$ in air was $10\~40$ times higher than that of the air- passivated particles.

• 한국표면공학회지
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• 제33권1호
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• pp.3-9
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• 2000

Arc-melted alloys of TiAl-(o.25, 0.5, 1.0at%) Si were isothermally oxidized at 800, 900 and $1000^{\circ}C$ in air for 60hr. It was found that the oxidation resistance of the prepared TiAl-Si alloys was much better than that of pure TiAl, being progressively increasing with an increase in the Si content. This was attributed to the formation of $SiO_2$in addition to ($TiO_2$+$Al_2$$O_3$) oxides which formed in TiAl alloys with and without silicon additions. However, the silica formation within the oxide layer unfortunately accelerated the oxide scale spallations. During oxidation, all the elements in the base alloy diffused outward, whereas oxygen from the atmosphere diffused inward. The oxides were primarily composed of an outer thick $TiO_2$layer, an intermediate diffuse $Al_2$$O_3$layer and an inner $TiO_2$layer. A small amount of $SiO_2$was present all over the oxide scale and some voids were found around the intermediate layer.

• 한국축산식품학회지
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• 제37권1호
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• pp.114-122
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• 2017

This study was conducted to evaluate the effects of clove extract (CE) (0.25%, 0.5%, 1%, and 2%) on the oxidative stability and quality deterioration of Chinese-style sausage stored for 21 d at $4^{\circ}C$. The addition of clove extract to sausages significantly retarded increases in Thiobarbituric Reactive Substances (TBARS) values (p<0.05), while also controlling the production of protein carbonyls (p<0.05). However, the addition of clove extract promoted reduced thiol group content in sausages (p<0.05). Sausages amended with clove extract also had decreased $L^*$ values (p<0.05) and increased $a^*$ values (p<0.05) when compared with the control. Similarly, texture deterioration was retarded in sausage containing added clove extract when compared with the control during refrigerated storage. Moreover, the addition of clove extract had no negative effects on the sensory properties of sausages. These results suggested that clove extract was effective at protecting sausages from oxidation and quality deterioration during refrigerated storage for 21 d.

• 한국식품영양과학회지
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• 제31권2호
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• pp.189-195
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• 2002

전분의 물리화학적 성질과 기능 특성을 개선하여 식품에서의 이용성을 확대하고자, 0.25, 0.5, 0.75, 1.0과 1.5% active Cl/g starch를 포함하는 NaOCl 용액으로 pH 7.0, $25^{\circ}C$에서 10분간 처리하여 산화 전분을 제조한 후 산화전분의 이화학적 특성과 호화 특성을 비교 분석하였다. 산화전분은 입자의 형태와 크기에 차이가 없었고, 뚜렷한 복굴절 현상을 보였다. 무처리 전분과 산화전분의 겉보기 아밀로오스 함량은 차이가 없었으며, 가용성 아밀로오스의 함량은 증가하였다 산화됨에 따라 X-선 회절도의 피크 강도와 위치가 변하여 상대적 결정화도가 감소하였고, 용해도와 팽윤력이 증가하였다. 아밀로그램에서 산화전분은 호화 개시 온도가 무처리 전분과 차이가 없었으나 산화제의 처리 농도가 증가됨에 따라 최고 점도와 setback이 감소하였다.

• 한국재료학회지
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• 제24권1호
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• pp.43-47
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• 2014

NiO-doped hibonite pigments were synthesized by the solid state method to get stabilized blue color pigment in both oxidation and reduction atmospheres. Optimum substitution condition with NiO for hibonite blue pigment was investigated. Experimental results were comparable to those of previous cobalt-minimization studies performed with other phosphate- or oxide-based cobalt-containing ceramic pigments (having olivine ($Co_2SiO_4$), spinel ($CoAl_2O_4$), or with co-doped willemite ($(Co,Zn)_2SiO_4$) structures). Composition was designed varying the NiO molar ratio increasing with $SnO_2$. The optimum substitution content is 0.93 mole NiO with 0.75mole $SnO_2$. The characteristics of the synthesized pigment were analyzed by XRD, Raman spectroscopy, SEM, and UV-vis. Synthesized pigment was applied to a lime-barium glaze with 10 wt% each and fired at an oxidation atmosphere of $1250^{\circ}C/1h$ and a reducing atmosphere $1240^{\circ}C/1h$. Blue color was obtained with $L^*a^*b^*$ values at 43.39, -6.78, -18.20 under a reducing atmosphere and 41.66, -6.36, -14.7 under and oxidation atmosphere, respectively.