• 한국식품과학회지
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• 제25권5호
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• pp.517-520
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• 1993

돈육의 pH가 5.0에서 7.0으로 증가할수록 저장중 산패치는 유의차 있게 감소하였다. 본 실험 결과 고 pH 돈육의 낮은 유리철 함량과 높은 GPx 활성은 저장중 돈육의 산패 억제에 관여하는 중요한 요인들인 것으로 밝혀졌다. 그러나 pH 조절에 의한 산패 억제에 관여할 수 있는 그 밖의 다른 가능한 인자들을 찾는 연구 또한 중요하다고 하겠다. 나아가서 유리철 ion의 방출 억제나 불활성화 방안, GPx의 또 다른 활성화 방안 및 천연항산화제로서의 활용 가능성등이 계속 연구, 검토되어야 할 것이다. 본 연구의 결과는 돈육의 저장성 증진은 물론, 규명된 항산화 기작들을 다른 작품 system에 응용하는 데에도 이용될 수 있을 것으로 본다.

• 한국축산식품학회지
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• 제36권1호
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• pp.44-50
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• 2016

This study was conducted to observe the association between antioxidant enzyme activity, free iron content and lipid oxidation of Korean native chicken (KNC) meat during refrigerated storage. Four lines of KNC (Yeonsan ogye, Hyunin black, Hoengseong yakdak and Hwangbong) were raised under similar conditions. A total of 16 roosters were randomly sampled and slaughtered at the age of 12 mon. The breast and thigh meats were stored aerobically for 10 d at 4℃. Although thigh meat had higher antioxidant enzyme activity, it was more susceptible to lipid oxidation and released more iron during storage than breast meat. Aerobic refrigerated storage for 10 d significantly decreased the activity of antioxidant enzymes and increased the amount of free iron and malondialdehyde. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were negatively correlated with lipid oxidation, whereas that of catalase was not. The amount of free iron was positively associated with lipid oxidation. We concluded that chicken line did not affect strongly on antioxidant enzyme activity and lipid oxidation in breast meat of KNC. However, the thigh meat of Hwangbong and Hyunin black had higher SOD and GSH-Px activity, respectively, and lower malondialdehyde contents than that of other chickens. SOD, GSH-Px and free iron play significant roles in meat lipid oxidation during refrigerated storage.

• Plant Resources
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• 제1권1호
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• pp.1-5
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• 1998

Total iron content and ferritin distribution have been determined in red pepper(Capsicum annuum L.) during development stage under conditions of iron nutritional status from hydroponic culture. Color of the leaves become chlorotic on iron deficient and high concentration. The plant height on each iron concentration had retarding effect at concentration lower than $25\muM$ and greater than 125$25\muM$. In normal green leaves. Total iron content was almost constant with a mean value of $2.5\mumole$ of iron/mg of dry matter, except at 63day, for which it increases slightly to $4\mumole$. Howere, iron content of chlorotic plants grew on iron free medium was not almost detectable. Also in post chlorotic leaves(++Fe), iron content was evidently increase unitl 7days after transfer on liquid medium, but decreased from after 14days. Also, ferritin protein analysed total protein extracts prepared from leaves of different ages using antibodies raised against ferritin protein. Ferritin protein deereased progressively during the first week of germination and was not detectable in vegetative tissues. Ferritin protein in post chlorotic leaves wasevidently strongly cnhanced until 11days after transfer on liquid medium but decreased until the leves became chlorotic.

• 한국주조공학회지
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• 제6권4호
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• pp.277-283
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• 1986

The effects of copper as an alloying element on the microstructure of Compacted Vermicular graphite cast iron which was treated with Mg-REM spheroidizer have been studied. With the increase of copper content up to 2.0wt.%, the following results were obtained; First, the ratio of residual magnesium content in the as-cast iron has been found to be increased, possibly due to the decrease of sulfur content in the melt. Thus, the morphology of graphite in the as-cast iron has been found to be more nodular type. Second, the proportion of pearlite in the matrix has been found to he increased, however the matrix being with free carbide precipitates in the copper range of 1.2wt.% to 2.0wt.%. Third, the tensile strength of the as-cast iron in the temperature up to $400^{\circ}C$ was increased.

• BMB Reports
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• 제44권3호
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• pp.165-169
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• 2011

Excess free iron generates oxidative stress that may contribute to the pathogenesis of various causes of neurodegenerative diseases. In this study, we assessed the modification of ferritin induced by $H_2O_2$. When ferritin was incubated with $H_2O_2$, the degradation of ferritin L-chain increased with the $H_2O_2$ concentration whereas ferritin H-chain was remained. Free radical scavengers, azide, thiourea, and N-acetyl-$_L$-cysteine suppressed the $H_2O_2$-mediated ferritin modification. The iron specific chelator, deferoxamine, effectively prevented $H_2O_2$-mediated ferritin degradation in modified ferritin. The release of iron ions from ferritin was increased in $H_2O_2$ concentration-dependent manner. The present results suggest that free radicals may play a role in the modification and iron releasing of ferritin by $H_2O_2$. It is assumed that oxidative damage of ferritin by $H_2O_2$ may induce the increase of iron content in cells and subsequently lead to the deleterious condition.

• 한국초전도ㆍ저온공학회논문지
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• 제23권3호
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• pp.5-9
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• 2021

Comprehensive utilization of sulfur-containing iron tailings (SIT) not only solves environmental problems but also creates certain economic value. The iron element from SIT was enriched by the superconducting high gradient magnetic separation (S-HGMS) technology in this study. In the experiments, the total iron content (TFe) was increased from 26.3% to 60.5% with the total sulfur content (TS) of 5.9% under the optimal parameters, i.e., a magnetic flux density of 0.4 T, a slurry flow rate of 1500 mL/min. The high-quality sulfur-containing material with TFe of more than 60% was obtained, which can be used for preparing high-sulfur free cutting steel. The S-HGMS technology can realize the resource utilization of iron tailings with high added value.

• Food Science and Biotechnology
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• 제14권1호
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• pp.152-163
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• 2005

Lipid peroxidation is a primary cause of quality deterioration in meat and meat products. Free radical chain reaction is the mechanism of lipid peroxidation and reactive oxygen species (ROS) such as hydroxyl radical and hydroperoxyl radical are the major initiators of the chain reaction. Lipid peroxyl radical and alkoxyl radical formed from the initial reactions are also capable of abstracting a hydrogen atom from lipid molecules to initiate the chain reaction and propagating the chain reaction. Much attention has been paid to the role of iron as a primary catalyst of lipid peroxidation. Especially, heme proteins such as myoglobin and hemoglobin and "free" iron have been regarded as major catalysts for initiation, and iron-oxygen complexes (ferryl and perferryl radical) are even considered as initiators of lipid peroxidation in meat and meat products. Yet, which iron type and how iron is involved in lipid peroxidation in meat are still debatable. This review is focused on the potential roles of ROS and iron as primary initiators and a major catalyst, respectively, on the development of lipid peroxidation in meat and meat products. Effects of various other factors such as meat species, muscle type, fat content, oxygen availability, cooking, storage temperature, the presence of salt that affect lipid peroxidation in meat and meat products are also discussed.

• 한국식품과학회지
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• 제31권2호
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• pp.527-534
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• 1999

솔잎의 제조방법별 열수추출물(HPNP, CPNP, FPN)의 항산화성을 검토하기 위하여 in vitro상에서 실험을 수행하였다. 각 추출물들의 지방산화 억제능을 측정한 결과, $Fe^{2+}$이온 첨가구에서는 HPNP와 FPN이 $Fe^{2+}$ 이온 binding능력이 우수하였으나, CPNP는 오히려 지방산화를 촉진하였고, $Fe^{3+}$이온 첨가구에서는 $Fe^{3+}$이온 binding능력은 없는 것으로 나타났다. 활성 산소종 존재 하에서 솔잎추출물의 첨가가 지방산화에 미치는 영향은 활성산소종보다 지방산화도가 오히려 높게 나타났으며, 가장 낮은 값을 나타낸 FPN도 $KO_2$보다 높게 나타나 포집능력은 없는 것으로 나타났다. 지방산화를 촉진하는 iron 함량은 ferrous iron과 total iron 모두 CPNP가 가장 높게 나타났고, 다음으로 HPNP, FPN순으로 나타났다. 항산화제인 ascorbic acid함량은 FPN, HPNP, CPNP 순으로 나타났다. 산화성 활성 free radical에 전자를 공여하여 산화를 억제시키는 척도인 전자공여능은 HPNP, CPNP, FPN순이었고, HPNP의 전자공여능이 가장 높은 것으로 나타났다. Speroxide dismutase (SOD) 유사활성을 측정한 결과 HPNP, CPNP, FPN순으로 나타나 SOD 유사활성능은 HPNP가 가장 우수하였다. 솔잎추출물을 각기 다른 pH에서 측정한 아질산염 분해능은 반응용액의 pH가 낮을수록 아질산염 분해능이 높게 나타났고 특히, pH 1.2에서 높은 분해능을 나타내었다.

• 미생물학회지
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• 제5권1호
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• pp.15-19
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• 1967

Chlorella ellipsoidea cells were cultured in an iron, copper, zinc, manganese, molybdenum or boron-free medium. Physiological activities such as growth rate, reproduction, endogenous and glucose respiration, photosynthetic activity and biosythesis of chlorophyll of the micro-element definition cells were measured. It generally, growth rate, respiratory and photosynthetic activities, and biosynthesis of chlorophyll of the micro-element deficient cells decreased more or less, compared with those of the normal cells. The growth of the algal cells in an iron-free medium were retarded severely with the chlorosis, and the photosynthetic activity of the cells decreased remarkably even though the low content of chlorophyll in the cells owing to the iron-deficiency is considered. Therefore, it is deduced that iron takes part in the photosynthetic process itself, possibly by its participation in the photo phosphorylation coupled with electron transport. Respiratory activity of boron-deficient cells showed the most severe decrease whereas those of the molybdenum-deficient cells showed very slight decrease in spite of severe growth retardation.

• Journal of Microbiology and Biotechnology
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• 제19권6호
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• pp.604-609
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• 2009

To investigate the potential use of microbial heme as an iron source, recombinant Escherichia coli coexpressing ALA synthase (HemA) as well as the NADP-dependent malic enzyme (MaeB) and dicarboxylic acid transporter (DctA) were cultured. The typical red pigment extracted from the recombinant E. coli after 38 h showed highest absorbance at 407 nm, and the amount of iron in 38.4 mg of microbial heme extract derived from 6-1 fermentation broth was 4.1 mg. To determine the commercial potential of the recombinant E.coli-synthesized iron-associated heme as an iron source, mice were fed the iron-free provender with the microbial heme extract. The average body weight reduction of mice fed non-iron provender was 2.3%, whereas no detectable weight loss was evident in mice fed microbial heme addition after 15 days. The heme content of the blood from microbial heme fed mice was 4.2 mg/ml whereas that of controls was 2.4 mg/ml, which implies that the microbial heme could be available for use as an animal iron source.