• Title/Summary/Keyword: oxidation time

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Effect of freezing on electrical properties and quality of thawed chicken breast meat

  • Wei, Ran;Wang, Peng;Han, Minyi;Chen, Tianhao;Xu, Xinglian;Zhou, Guanghong
    • Asian-Australasian Journal of Animal Sciences
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    • v.30 no.4
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    • pp.569-575
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    • 2017
  • Objective: The objective of this research was to study the electrical properties and quality of frozen-thawed chicken breast meat and to investigate the relationship between these parameters at different times of frozen storage. Methods: Thawed samples of chicken breast muscles were evaluated after being kept in frozen storage at $-18^{\circ}C$ for different periods of time (1, 2, 3, 4, 5, 6, 7, and 8 months). Results: The results showed that water-holding capacity (WHC) and protein solubility decreased while thiobarbituric acid-reactive substances content increased with increasing storage time. The impedance module of samples decreased during 8-month frozen storage. Pearson correlation coefficients showed that the impedance change ratio (Q value) was significantly (p<0.05) related to pH, color, WHC, lipid oxidation and protein solubility, indicating a good relationship between the electrical properties and qualities of frozen-thawed chicken breast meat. Conclusion: Impedance measurement has a potential to assess the quality of frozen chicken meat combining with quality indices.

Removal of As(III) by Pilot-Scale Filtration System Separately Packed with Iron-Coated Sand and Manganese-Coated Sand (철 및 망간코팅사를 분리 충진시킨 파일럿 여과시스템에 의한 3가 비소 제거)

  • Kim, Kwang-Seob;Song, Ki-Hoon;Yang, Jae-Kyu;Chang, Yoon-Young
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.8
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    • pp.878-883
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    • 2006
  • Removal efficiency of As(III) was investigated with a pilot-scale filtration system packed with an equal amount(each 21.5 kg) of manganese-coated sand(MCS) in the bottom and iron-coated sand(ICS) in the top. Height and diameter of the used column was 200 cm and 15 cm, respectively. The As(III) solution was introduced into the bottom of the filtration system with a peristaltic pump at a speed of $5{\times}10^{-3}$ cm/s over 148 days. Breakthrough of total arsenic in the mid-sampling position(end of the MCS bed) and final-sampling position(end of the ICS bed) was started after 18 and 44 days, respectively, and then showed a complete breakthrough after 148 days. Although the breakthrough of total arsenic in the mid-sampling position was started after 18 days, the concentration of As(III) in this effluent was below 50 ppb up to 61 days. This result indicates that MCS has a sufficient oxidizing capacity to As(III) and can oxidize 92 mg of As(III) with 1 kg of MCS up to 61 days. When a complete breakthrough of total arsenic occurred, the removed total arsenic by MCS was calculated as 79.0 mg with 1 kg MCS. As variation of head loss is small at each sampling position over the entire reaction time, it was possible to operate the filtration system with ICS and MCS for a long time without a significant head loss.

Lipid Oxidation in Shellfish under the Different Conditions of Drying (패류의 건조조건에 따른 지질산화)

  • LEE Kang-Ho;CHO Tae-Yong;CHO Ho-Sung;LEE Jong-Ho;SHIM Ki-Hwan
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.31 no.2
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    • pp.143-148
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    • 1998
  • This study was carried out in order to investigate oxidative deterioration during dehydration at $40^{\circ}C,\;50^{\circ}C$ and $60^{\circ}C$ of sea mussel and baby clam. Moisture content was decreased with drying temperature and time. Sea mussel was dehydrated more rapidly than baby clam that had Harder muscle tissue. Both samples were not reached to Aw 0.62 in case of 10 hrs drying at $40^{\circ}C$, But it reached within 8 hrs in sea mussel and 10 hrs in baby clam at $50^{\circ}C$, respectively. Even if $60^{\circ}C$ could speed up drying, it caused to form more free fatty acid, peroxide, thiobarbituric acid and brown pigments. Lipophilic brown pigment was 10 times higher than hydrophilic and actively increased in all samples. fluorescence intensity was also increased with drying temperature and time. Particularly, it was higher sea mussel than baby clam more or less.

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Benzo(a)pyrene Reduction in Sesame Oil Using Microwaving Method (Microwaving을 이용한 참기름의 Benzo(a)pyrene 저감화)

  • Oh, Sung-Cheon
    • Journal of the Korean Applied Science and Technology
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    • v.29 no.2
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    • pp.323-329
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    • 2012
  • Sesame oil has superior oxidation stability and unique roasting flavor. Accordingly, this has been used for edible oil as well as a seasoning material for a long time in Korea. But sesame oil is a simple pressed oil, unrefined. During manufacturing process of roasting-expression, benzo(a)pyrene[B(a)P] formed as a strong carcinogenic substance causes a social problem. Detection of B(a)P in sesame oil was due to residual content in raw-sesame seeds and formation in roasting-expressing process. Especially, maximal forming process was roasting. Accordingly, in this study applied the traditional roasting method by roaster and microwaving method as a new type. Best roasting time by microwaving was for 5~10 min, B(a)P content in sesame oil was 0.53~0.79 ${\mu}g/kg$. These B(a)P contents showed 1/2 level than direct roasting method by roaster. As a result, B(a)P contents in sesame oil appeared the difference of more than 2 times according to roasting condition of sesame seed. For minimizing of B(a)P content in sesame oil is demanded roasting of sesame by microwaving than direct roasting by roaster.

Effect of Inorganic Coagulants on the Performance of Electro-Chemical Treatment Process Treating Hospital Wastewater (병원폐수의 전기화학적 처리시 무기응집제 주입 효과에 관한 연구)

  • Jeong, Seung-Hyun;Jeong, Byung-Gon
    • Journal of Korean Society of Environmental Engineers
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    • v.33 no.10
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    • pp.709-716
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    • 2011
  • Effect of inorganic coagulants dosing on the performance of electro-chemical process was studied when treating hospital wastewater having low electrolyte concentration. It is thought that adding inorganic coagulants caused increase in concentration of electrolyte and this caused increase in free chloride concentration and consequently, caused increase in indirect oxidation effect. Thus, COD removal efficiencies more than doubled in percentage terms at the 2 hrs of reaction time and current density of $1.76A/dm^2$ compared with the results obtained from the parallel experiments without adding inorganic coagulants. T-N removal efficiencies approximately doubled in percentage terms at the 2 hrs of reaction time and 700 ppm of coagulants addition and applied current density of $1.76A/dm^2$ due to the increase of free residual chlorine such as HOCl caused by increase of electrolyte concentration through the addition of inorganic coagulants. Under the same experimental condition, more than 90% of T-P removal efficiencies was obtained. The reason can be explained that increase of chemical adsorption rate between phosphate and insoluble metal compounds caused by dissolved oxygen generated from anode by the increased electrolyte concentration through inorganic coagulants addition make a major role in improving T-P removal efficiencies. It can be concluded that inorganic coagulants addition as the supplemental agent of electrolyte is effective way in improving organic and nutrient salt removal efficiency when treating hospital wastewater having low electrolyte concentration.

Effects of Seeding Microorganisms, Hydrazine, and Nitrite Concentration on the Anammox Activity (혐기성 암모늄 산화균의 활성에 대한 식종미생물, 히드라진 및 아질산성 질소 농도의 영향)

  • Jung, Jin-Young;Kang, Shin-Hyun;Kim, Young-O;Chung, Yun-Chul
    • Journal of Korean Society on Water Environment
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    • v.21 no.5
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    • pp.477-483
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    • 2005
  • Anammox (Anaerobic Ammonium Oxidation) bacteria is recently discovered microorganism which can oxidize ammonium to nitrogen gas in the presence of nitrite under anaerobic conditions. The anammox process can save an energy for nitrification and need not require a carbon source for denitrification, however, the start-up periods takes a long time more than several months due to the long doubling time (approximately 11 days). In order to find the effects of seeding microorganisms, hydrazine, and nitrite concentration on the enhancement of the anammox activity, five kinds of microorganisms were selected. Among the several kinds of seeding microorganisms, the granule from acclimated microorganisms treating high concentration of ammonia nitrogen (A-1) and sludge from piggery wastewater treatment plant (A-2) were found to have a high anammox activity. In the case of A-1, the maximum nitrogen conversion rate represented 0.4 mg N/L-hr, and the amount of nitrite utilization was high compared to those of other seeding microorganisms. The A-4 represented a higher nitrogen conversion rate to 0.7 mg N/L-hr although the ammonium concentration in the serum bottle was high as 200 mg/L. Meanwhile, the anaerobic granule from UASB reactor treating distillery wastewater showed a low anammox activity due to the denitrification by the remained carbon sources in the granule. Hydrazine, intermediate product in anammox reaction, enhanced the anammox activity by representing 1.4 times of nitrogen gas was produced in the test bottle than that of control, when 0.4 mM of $N_2H_4$ was added to serum bottle which contains 5 mM of nitrite. The high concentration of nitrite (10 mM) resulted in the decrease of the anammox activity by showing lower production of nitrogen gas compared to that of 5 mM addition of nitrite concentration. As a result of FISH (Florescence In-Situ Hybridization) experiment, the Amx820 probe showed a more than 13% of anammox bacteria in a granule (A-1).

Physicochemical Properties of Modified Chufa (Cyperus esculentus L., var sativus Boeck) Starch (기름골 변성전분의 물리화학적 특성)

  • Han Sang-Ha;Lee Hyun-Yu;Kum Jun-Seok;Park Jong-Dae
    • Food Science and Preservation
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    • v.13 no.3
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    • pp.404-412
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    • 2006
  • TThe purpose of this study was to investigate the physicochemical properties of chufa(Cyperus esculentus L., var sativus Boeck) starches by physical and chemical modification. Chufa starches were exposed to the microwave with 700W power oven for 1, 2, and 3 minutes. Also, starch was oxidized with 1.5%, 3% and 6% (15, 30, 60 mg Cl2/g starch $40^{\circ}\C$, pH 10, 3.0 hr) sodium hypochlorite. The shape of starch granules was not changed much by microwave heating and sodium hypochlorite. Water binding capacity increased but amylose content swelling power, and solubility decreased with increasing microwave heating time. Water binding capacity of the oxidized starch decreased with increasing the content of sodium hypochlorite. With increasing the microwave heating time, gelatinization temperature decreased, but enthalpy(${\Delta}H$) increased in physical modification of chufa starches. Also, chemically modified chufa starches have the similar pattern in gelatinization properties. Peak viscosities of RVA in physically modified chufa starches were 416-188 RVU, and in chemically modified chufa starches they were 129-267 RVU.

Studies on the Pollution-Free Pulping by Nitric Acid - Nitric Acid Pulping of Alkali-Pretreated Wood - (질산(窒酸)을 이용한 무공해(無公害)펄프 제조(製造)에 관한 연구(硏究) - 알카리 전처리재(前處理材)의 질산(窒酸)펄프화에 관하여 -)

  • Cho, Nam Seok
    • Journal of Korean Society of Forest Science
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    • v.61 no.1
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    • pp.27-36
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    • 1983
  • This study was performed to get the basic information on nitric acid pulping of beech wood. In order to reduce the consumption of nitric acid, alkali pretreated woods were applied to a nitric acid pulping process. It consisted of nitric acid treatment to a high residual lignin content and the subsequent delignification with alkali, required far less chemical than the single stage method. At the first stage of nitric pulping, pulp yield descreased with increasing cooking time and 3 percent of nitric acid was more effective on the delignification of wood than 1 or 2 percent. Alkali pretreatment of wood improved significantly the rate of delignification, and 79 percent of the pretreated yield was good enough for excellent delignification. The dissolution of carbohydrate (mainly xylose) was increased with increasing cooking time, especially at the second stage. It would be considered that carbonyl groups introduced to polysaccharides in wood by nitric acid oxidation caused the degradation of carbohydrates.

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Processing of Ready-to-Cook Food Materials with Dark Fleshed Fish 2. Processing of Ready-to-Cook Low Salt Mackerel Fillet (일시다획성 적색육어류를 이용한 중간식품소재 개발에 관한 연구 2. 저염 고등어 Fillet의 가공)

  • LEE Byeong-Ho;LEE Kang-Ho;YOU Byeong-Jin;SUH Jae-Soo;JEONG In-Hak;CHOI Byeong-Dae;JI Young-Ae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.18 no.5
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    • pp.409-416
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    • 1985
  • In previous paper (Lee et al., 1983) processing method of sardine meat "surimi" was described as a part of the wort to develop new types of ready-to-cook food materials with dark fleshed fishes. As the other part of the work, processing of low salt mackerel fillet was investigated, in this paper, in which fresh mackerel was filleted, salted in brine or with dry salt for an adequate time until the expected salt concentration reached, washed, air dried (3 m/sec, 15 to $20^{\circ}C$), and finally packed individually in K-flex film bag by vacuum or $N_2$ gas substitution. Salting time and salt concentration of brine was decided by the salt level penetrated into the fillet. As the final salt level was fixed to 4 to $5\%$, salting for 20 hours with $10\%$ dry salt or in $15\%$ brine at $5^{\circ}C$ was enough to get that level of salt. If the final salt level was set 5 to $6\%$, salting for 20-24 hours with $15\%$ dry salt or in $20\%$ brine was adequate. Salt penetration, however, was not much influenced by salting method and temperature. Changes in VBN and salt soluble protein occurred more rapidly in cases of salting with dry salt at $20^{\circ}C$ than salted in brine at $5^{\circ}C$, although it was not significant in the period of 20 to 24 hours. Oxidation of lipid and histamine formation during salting at $20^{\circ}C$ could not be neglected if it was delayed loger than 25 hours. Insolubilizing the salt soluble proteins during the storage of salted fillet occurred rapidly regardless of storage temperature. Browning and histamine formation, however, was depended on temperature and packing condition. In case of air pack, deterioration by browning and rancid was deeply developed but not the case for the packs by vacuum or $N_2$ gas substitution. The shelf-life of the salted mackerel fillet based on panel scores of brown color and rancidity, appeared 21 days for the air packed, and more than 30 days for vacunm or $N_2$ gas packed fillet at $20^{\circ}C$.

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Characteristics of Organic Carbon Species in Atmospheric Aerosol Particles at a Gwangju Area During Summer and Winter (여름 및 겨울철 광주지역 대기 에어로졸 입자의 유기탄소 특성)

  • Park, Seung-Shik;Hur, Jai-Young;Cho, Sung-Y.;Kim, Seung-J.;Kim, Young-Joon
    • Journal of Korean Society for Atmospheric Environment
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    • v.23 no.6
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    • pp.675-688
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    • 2007
  • To characterize organic and elemental carbon (OC and EC), and water-soluble organic carbon (WSOC) contents, daily $PM_{2.5}$ measurements were performed in August 2006 (summer) and Jan $11{\sim}Feb$ 12 2007 (winter) at an urban site of Gwangju. Daily size-segregated aerosol samples were also collected for WSOC analysis. No clear seasonal variations in EC and WSOC concentrations were observed, while seasonal differences in OC concentration, and OC/EC and WSOC/EC ratios were shown. The WSOC/OC ratio showed higher value in summer (0.56) than in winter (0.40), reflecting the greater enhancement of secondary WSOC formation at the site in summer. Secondary WSOC concentrations estimated using EC tracer method were in the range $0.0{\sim}2.1\;{\mu}g/m^3$ (average $0.42\;{\mu}g/m^3$) and $0.0{\sim}1.1\;{\mu}g/m^3\;(0.24\;{\mu}g/m^3)$, respectively, accounting for $0{\sim}51.6%$ (average 16.8%) and $0{\sim}52.5%$ (average 13.1 %) of the measured WSOC concentrations in summer and winter. Sometimes higher WSOC/OC ratio in winter than that in summer could be attributed to two reasons. One is that the stable atmospheric condition often appears in winter, and the prolonged residence time would strengthen atmospheric oxidation of volatile organic compounds. The other is that decrease of ambient temperature in winter would enhance the condensation of volatile secondary WSOC on pre-existing aerosols. In summertime, atmospheric aerosols and WSOC concentrations showed bimodal size distributions, peaking at the size ranges $0.32{\sim}0.56\;{\mu}m$ (condensation mode) and $3.2{\sim}5.6\;{\mu}m$ (coarse mode), respectively. During the wintertime, atmospheric aerosols showed a bimodal character, while WSOC concentrations showed a unimodal pattern. Size distributions of atmospheric aerosols and WSOC with a peak in the size range $0.32{\sim}0.56\;{\mu}m$ were observed for most of the measurement periods. On January 17, however, atmospheric aerosols and WOSC exhibited size distributions with modal peaks in the size range $1.0{\sim}1.8\;{\mu}m$, suggesting that the aerosol particles collected on that day could be expected to be more aged, i.e, longer residence time, than the aerosols at other sampling periods.