• 환경위생공학
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• 제12권3호
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• pp.19-29
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• 1997

The Chemical Oxygen Demand(COD) by potassium permanganate and potassium dichromate is used as a measure of the organic matter content of a sample. Newly proposed $K_{2}Cr_{2}O_{7}$ analysis method to be list at Korean Official Method was made from analysis and comparison of the experimental process on Japanese Industrial Standard(JIS), American Open Reflux and Closed Reflux Methods. New $K_{2}Cr_{2}O_{7}$ method had better the qualitative and reproducible COD results than another methods as a result of the tested four times repeatedly by using Lakes water Plant wastewater. The COD data ratio by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ methods was 2-3, 3, 2-17 and 3-4 times respectively when its data had compared with the lakes water and treated water of domestic and experimental wastewater, and raw wastewater which is generated at the manufacturing process of 6 steps and treated wastewater of chemistry source. Its ratio indicated to 2-4 and 2-3 times respectively on raw wastewater and plant wastewater of Chemistry, rubber and plastic, fiber, metal molding source. Oxidation ratio of benzene and ethyl benzene by $KMnO_{4}$ method was nearly zero, but the oxidation ratio by $K$_{2}Cr_{2}O_{7}$ method was 50%, 70% respectively. Also, Oxidation ratio of phenol by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ methods was 80%, 100% respectively, and trichloroethylene and tetrachloroethylene were not nearly oxidizd by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ methods. As the above contents, oxidation ratio and COD results by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ were different from various from various compounds and samples respectively.

• 한국식생활문화학회지
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• 제34권6호
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• pp.771-778
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• 2019

This study investigated the effect of temperature deviation on the water-holding capacity, tenderness, lipid oxidation, and color stability of Korean Hanwoo (韓牛) beef during long-term aging. The striploins (M. longissimus lumborum) were aged for 56 days at 2±1℃ (T1), 2±2℃ (T2), or 2±3℃ (T3). Drip loss and cooking loss were higher (p<0.05) in T3 than in T1 on day 56. The Warner-Bratzler shear force value was similar for all treatments during aging times. On day 56, the content of 2-thiobarbituric acid reactive substances was higher (p<0.05) in T3 as compared to T1. The CIE L^* and b^* values were similar for all treatments, but the a^* value was lower (p<0.05) in T3 than in T1 on the last day. These findings indicate that high temperature deviation adversely affects the water-holding capacity, lipid oxidation stability, and color stability of Hanwoo beef during long-term aging.

• 한국식품과학회지
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• 제27권6호
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• pp.902-908
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• 1995

배소김과 조미김의 저장중 지방질 산화의 변질요인을 조사하기 위하여 몇가지 광원, $a_w$, 포장 및 온도의 영향을 시험하였다. 배소김의 주요 지방산 조성은 16 : 0(14.9%) 및 20 : 5(46.4%) 이었다. 배소김과 조미김의 지방질 산화는 형광등 하에서 가장 심하였고 다음이 백열등, 암소저장 순 이었으며, 또한 지방질의 산화는 $a_w$가 증가할수록, 저장온도가 높을수록 급격히 증가하는 경향을 보였고 기체 및 광 차단 효과가 큰 포장지에 포장한 시료일수록 산화가 억제 되었다. 배소김과 조미김의 지방질 산화를 kinetics 측면에서 고찰한 결과 조미김의 지방질 산화가 배소김 보다 약 3배 빨랐으나 chlorophyll 감소량은 배소김이 조미김 보다 약간 많았다.

• 한국식품영양과학회지
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• 제24권3호
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• pp.384-388
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• 1995

어유는 고도불포화지방산 함량이 높아 산화가 쉽게 되므로 식품가공용이나 기능성식품으로 응용되기에는 많은 제약이 따른다. 이러한 문제를 해결하기 위하여 어유의 산화안정성을 예측할 수 있는 기본 모델을 다음과 같은 식을 이용하여 제시하였다. $dp/dt=k{\cdot}p(t){\cdot}[P_{max}\;-\;p(t)]$. 상기식을 적분하면, $p(t)=P_{max}/[1\;+\;[(P_{max}/P_{(0)})\;-\;-1]{\cdot}EXP(-K_p{\cdot}t)]$. 여기서 산화온도가 50, 60와 70 및 $80^{\circ}C$ 일 때, $K_p$는 각각 0.00535, 0.01345와 0.02516 및 0.04657였다. 상기식은 대부분 측정치와 잘 일치하였다. 또한 $K_p$를 아래와 같이 온도의 함수로 표현할 수 있었다. $K_p=(1/P_{max})EXP\;[1\;-\;(8148/T)+20.1]$. 여기서 T 절대온도($^{o}K$)이다.

• 한국수소및신에너지학회논문집
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• 제23권4호
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• pp.346-352
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• 2012

The properties of methane oxidation were studied in this research over transition metal containing $CeO_2$ (TM/$CeO_2$, TM=Ni, Co, Cu, Fe) with TM content of 5 wt. % at atmospheric pressure. The characteristics of catalysts were investigated by various characterization techniques, including XRD, GC, SEM and EPMA analyses. The catalytic tests were carried out in a fixed Rmix ratio of 1.5 ($CH_4/O_2$) in a fixed-bed reactor operating isothermally at atmospheric pressure. Only the Ni/$CeO_2$ catalysts showed syngas production above $400^{\circ}C$ via typical partial oxidation reaction whereas other catalysts induced complete oxidation resulting in the production of $CO_2$ and $H_2O$ in whole reaction temperature range. From the quantitative analysis on carbon deposition after catalytic tests, Cu/$CeO_2$ was found to show the highest resistance on carbon deposition. Therefore Cu can be proposed as an efficient catalyst element which can be combined with a conventional Ni-based SOFC anode to enhance the carbon tolerance.

• 한국축산식품학회지
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• 제38권6호
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• pp.1203-1215
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• 2018

The antioxidant effects of Allium hookeri root (AHR) were investigated by evaluating lipid and protein oxidation in meatballs during refrigerated storage at $4{\pm}1^{\circ}C$. AHR was mixed at concentrations of 0.5% (w/w, T2) and 1% (w/w, T3) with minced longissimus dorsi muscle. Meatballs containing AHR (T2 and T3) were compared to those containing 0.05% (w/w) ascorbic acid (T1) as a reference and without antioxidant as a control. The 2-thiobarbituric acid reactive substances (TBARS) value, disulfide bond formation, carbonyl contents, and volatile basic nitrogen (VBN) value of T2 were lower than those of the control during storage (p<0.05). The pH values of T2 and T3 were higher than that of the control (p<0.05). Texture profile analysis of T2 revealed a lower value compared to the control (p<0.05). Therefore, the VBN value, TBARS value, disulfide bond formation, and carbonyl content in meatball containing AHR were lower than those of the control meatball. These results indicate that AHR improves the quality of meat products and functions as an antioxidant.

• 한국축산식품학회지
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• 제39권3호
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• pp.446-458
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• 2019

The aim of this study was to investigate the oxidative status and quality characteristics of four animal skin-derived fats extracted using an identical extraction method. Pressurized hot water extraction, a green extraction method, was used to extract animal skin fats (duck, chicken, swine, and bovine skin). Multiple experiments were performed during accelerated storage at $60^{\circ}C$ for 90 days. Quality characteristics, such as extraction yield, iodine value (IV), fatty acid composition, and fat viscosity were determined. In addition, indicators for oxidative status, including acid value (AV), peroxide value (PV), p-anisidine value (p-AV), thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD), and total oxidation (totox) values were evaluated. The fat extraction yield was highest in bovine fat, followed by duck, swine, and chicken fats. The IV was higher in duck and chicken fats. Duck fats contained the most unsaturated fats and the least saturated fats. Fat oxidation indicators, such as PV, TBARS, and totox values, were relatively higher in duck fats during storage compared to the other fats. Other indicators, including AV, p-AV, and CD, were similar in duck, chicken, and swine fats. Viscosity was similar in all the tested fats but markedly increased after 70 days of storage in duck fats. Our data indicate that duck skin fat was more vulnerable to oxidative changes in accelerated storage conditions and this may be due to its higher unsaturated fatty acid content. Supplementation with antioxidants might be a reasonable way to solve the oxidation issue in duck skin fats.

• Asian-Australasian Journal of Animal Sciences
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• 제32권6호
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• pp.874-880
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• 2019

Objective: Ozone is considered a strong antimicrobial agent with numerous potential applications in the food industry. However, its high oxidizing potential can induce alterations in foods by acting on the unsaturated fatty acids. The aim of this study was to investigate the effect of ozonation on the oxidative stability of chicken breast meat obtained from animals subjected to different feeding strategies. Methods: Samples were obtained from commercial hybrid chickens (ROSS 508), some of which were nourished with a feed enriched with fats of animal origin, while the lipid source was vegetal for the remaining birds. Samples of meat belonging to both groups were treated with ozone and then analysis was performed to evaluate alterations in physical properties, lipid content, fatty acid profile, and oxidation stability. Results: Ozone induced a significant reduction in drip loss in meat samples obtained from animals nourished with vegetable fats; this nutritional strategy also produced meats leaner and richer in polyunsaturated fatty acids. Thiobarbituric acid reactive substances, useful for the assessment of lipid oxidation, were higher in samples obtained from animals fed with vegetable fats with respect to diet based on the addition of animal fats. Conclusion: The ozone treatment improved the physical parameters of meat samples obtained from animals fed with vegetable fats, however the same samples showed a higher lipid oxidation compared to what observed in the case of the dietary intake of animal fats, probably as a consequence of the marked increase in polyunsaturated fatty acids which are more susceptible to peroxidation.

• 한국응용과학기술학회지
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• 제37권6호
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• pp.1583-1590
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• 2020

본 연구는 Cinnamomum loureiroi 추출물(CLE)의 항산화 활성을 확인하기 위해 수행되었다. 실험 전에 세포독성을 확인하였으며, 본 연구수행에서 사용할 농도의 안전성을 확보하였다. 추출물의 폴리페놀과 플라보노이드 함량을 측정하고 ABTS 라디칼과 DPPH 라디칼 소거능을 측정하였으며, LPS에 유도된 Raw 264.7 세포에서 ROS의 생성 감소를 확인하였다. 연구 결과 총 폴리페놀의 함량은 397.7±8.3 mg/g, 총 플라보노이드 함량은 101.9±0.8 mg/g으로 BHA 검량선 기준으로 선행연구들과 비교한 결과 함량비가 높은 것으로 나타났다. ABTS 라디칼과 DPPH 라디칼 소거율은 농도 의존적으로 증가하는 것으로 나타나 농도에 따라 항산화 활성이 높아지는 것으로 확인되었다. ROS 생성은 농도 의존적으로 유의한 감소를 나타내어 라디칼 소거능과 부합되는 결과를 나타냈다. 결과적으로 CLE의 항산화 활성이 확인되었으며, 향 후 천연원료로서 기능성화장품 또는 심화 연구를 통한 천연화장품의 응용할 가능성이 있는 것으로 사료된다.

• Animal Bioscience
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• 제35권6호
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• pp.884-891
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• 2022

Objective: Free-range systems have been increasingly available to the consumer due to increased demand for more sustainable meat-products. In the current study, the effect of free-range (FR) and cage system (CS) was explored on growth performance, meat quality and oxidation products in Italian White breed rabbits during the growing-fattening phase (5 to 13 weeks of age). Methods: Forty rabbits were randomly allotted to two treatment groups according to the rearing system, and each treatment group was replicated five times with four subjects in each replicate (20 rabbits per treatment-group). All rabbits fed the same diet as pelleted, and under FR system, no additional feeds were available to animals. Results: Rearing system had significant effect on rabbit growth performance, where CS group resulted in higher final body weight (p<0.045) and gain (p<0.029) and better feed efficiency (p<0.025) compared to FR rabbits. Most carcass traits were not affected by rearing system; however, a reduction of abdominal fat content (p<0.015) and meat lipids (p<0.034) was observed in FR rabbits. Rearing system had no effects on meat fatty acid profile, whereas meat from FR rabbits resulted less susceptible to lipid and protein oxidation compared to caged animals. Conclusion: In overall, FR system could be suggested as a substitute for conventional caged system because of FR system preserved rabbit meat from oxidation.