• Title, Summary, Keyword: autoxidation

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Effects of Fe(III) and Cu(II) Ions on the Autoxidation of L-Ascorbic Acid

  • Kim, Mi-Ok
    • Preventive Nutrition and Food Science
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    • v.6 no.2
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    • pp.83-86
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    • 2001
  • The autoxidation reaction of L-ascorbic acid(AsA), and, particularly, the oxidation rates of AsA in the presence of Fe(III) or Cu(II) ions were determined in water and methanol. UV spectral measurement (at 265 nm) and HPLC were used to determine the remaining amounts of AsA in water and methanol, respectively. It was found that, in the presence of metal ions, the autoxidation rate of AsA was significantly affected by the kinds of solvents used, and also by the kinds of metal ions present. Moreover, the first-order rate constants for the oxidation of non-dissociated AsA compared with dissociated-AsA were investigated. It was confirmed that the oxidation of AsA was more accelerated in the dissociated form of AsA than in the non-dissociated form of AsA in either with Fe(III) or Cu(II). It was also found that the Cu(II) at a concentration of 0.1 $\mu$M had a more significant effect on the first-order rate constants for the autoxidation of AsA than Fe(III) at 5 $\mu$M.

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Effects of Oleic Acid on the Autoxidation of Rice Bran Oil (미강유의 자동산화에 미치는 Oleic Acid의 첨가 효과)

  • 이성호;신영순
    • The Korean Journal of Food And Nutrition
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    • v.6 no.1
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    • pp.47-52
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    • 1993
  • In the present study, an attempt was made to investigate the effect of oleic acid on the autoxidation of the commercial rice bran oil. Rice bran oil samples with oleic acid at 0.1, 0.3 and 0.5% level were kept at 45 $\pm$ 0.3$^{\circ}C$ for 40 days. The rate of autoxidation of each samples was estimated regularly on the basis of the changes of peroxide value, acid value, anisidine value and the fatty acid composition. The per oxide, acid and anisidine values of the rice bran oil with the oleic acid increased as compared with that of the rice bran oil without the oleic acid during the autoxidation. The induction period of the rice bran oil without the oleic acid, control was 19.8 days, while those of the rice bran oil with oleic acid at 0.1, 0.3 and 0.5% levels were 18.3 days, 16.8 days, and 15.5 days, respectively. In conclusion, it seemed that oleic acid acted as weak prooxidant when added at 0.1, 0.3 and 0.5% levels to the commercial rice bran oil.

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Mechanism of DNA Cleavage Induced by Fe2+ Autoxidation

  • Kim, Jong-Moon;Kim, Seog-K.
    • Bulletin of the Korean Chemical Society
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    • v.32 no.3
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    • pp.964-972
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    • 2011
  • This work investigated the difference between $Fe^{2+}$ autoxidation-induced and Fenton-type cleavage of pBR322 plasmid DNA. $^{\cdot}OH$ generation reactions in the absence and presence of $H_2O_2$ under various conditions were also investigated. Although both the $Fe^{2+}$ autoxidation and Fenton-type reactions showed DNA cleavage and $^{\cdot}OH$ generation, there were significant differences in their efficiencies and reaction rates. The rate and efficiency of the cleavage reaction were higher in the absence of 1.0 mM of $H_2O_2$ than in its presence in 20 mM phosphate buffer. In contrast, the $^{\cdot}OH$ generation reaction was more prominent in the presence of $H_2O_2$ and showed a pH-independent, fast initial reaction rate, but the rate was decreased in the absence of $H_2O_2$ at across the entire tested pH range. Studies using radical scavengers on DNA cleavage and $^{\cdot}OH$ generation reactions in both the absence and presence of $H_2O_2$ confirmed that both reactions spontaneously involved the active oxygen species $^{\cdot}OH$, ${O_2}^{\cdot-}$, $^1O_2$ and $H_2O_2$, indicating that a similar process may participate in both reactions. Based on the above observations, a new mechanism for the $Fe^{2+}$ autoxidation-induced DNA cleavage reaction is proposed.

Effect of Addition of Egg Yolk Lecithin on the Lipid Oxidation of a Water/canola Oil Emulsion (달걀 노른자위 레시틴의 첨가가 물/카놀라 기름 에멀션의 지방질 산화에 미치는 영향)

  • Choe, Jeesu;Choe, Eunok
    • Korean Journal of Food Science and Technology
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    • v.47 no.5
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    • pp.561-566
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    • 2015
  • Effect of the addition of egg yolk lecithin at a concentration of 350 mg/kg on iron-catalyzed autoxidation and chlorophyll-photosensitized oxidation of a water/canola oil emulsion (W/O) during storage at $25^{\circ}C$ was studied based on headspace oxygen consumption and hydroperoxide production. Changes in the phospholipid (PL) composition of the emulsion were determined by high performance liquid chromatography. Headspace oxygen consumption and hydroperoxide content of the emulsion increased with storage time, and addition of egg yolk lecithin did not have any significant effect on these parameters during iron-catalyzed autoxidation and chlorophyll-photosensitized oxidation of the emulsion. PL content of the emulsion decreased during both oxidations, and the degradation rate was higher during autoxidation than during photosensitized oxidation. Phosphatidylcholine content ratio tended to increase during autoxidation. The results suggest that egg yolk lecithin in canola oil emulsion behaves differently during iron-catalyzed autoxidation and chlorophyll-photosensitized oxidation.

Isolation of Chlorophyll Derivatives and $\beta$-Carotene from Mustard Leaf and Their Antioxidative Activities on the Lipid Autoxidation (갓에서 Chlorophyll 유도체 및 $\beta$-Carotene의 분리와 이들의 항산화 작용)

  • 송은승;전영수;최홍식
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.30 no.3
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    • pp.377-381
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    • 2001
  • Chlorophyll a and b, pheophytin a and b and $\beta$-carotene, crude chlorophylls and carotenoids (CCC) extracts of mustard leaf kimchi were isolated by DEAE-sepharose CL-6B and Sepharose CL-6B colume and TLC. The effects of chlorophyll a and b, pheophytin a and b and $\beta$-carotene on linoleic acid autoxidation were examined by the determination of peroxide value and conjugated dienoic acid content. Among them, chlorophyll a showed greater antioxidative activity than others, followed by chlorophyll b, pheophytin a, pheophytin b and $\beta$-carotene. Degradation of pheophytin b was observed to be slower than others and $\beta$-carotene showed highest degradation level during the autoxidation reaction of linoleic acid.

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Effects of Clove Extracts on the Autoxidation and Thermal Oxidation of Soybean Oil (대두유의 자동산화 및 가열산화에 미치는 정향추출물의 항산화 효과)

  • 박상일;손종연
    • Korean journal of food and cookery science
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    • v.20 no.1
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    • pp.81-85
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    • 2004
  • This study was conducted to investigate the antioxidant activities of clove extracts in water, methanol and ether. The clove extracts, BHA and ${\alpha}$-tocopherol were added to each oil at a level of 200 ppm. The activities of the substrate oils and controls were tested under autoxidation and thermal oxidation conditions. The degree of the effects of the antioxidant activities under autoxidation condition were in the following order; ether extract 〉 methanol extract 〉BHA 〉 ${\alpha}$-tocopherol 〉 water extract = control group. The induction periods of the control, water, methanol and ether extracts, and BHA and ${\alpha}$-tocopherol were 9.5, 9.6, 10.7 11.8, 10.4 and 9.7 days, respectively. Under thermal oxidation condition, the methanol extract showed stronger antioxidant activity than those of the water and ether extracts. The antioxidant activity of the methanol extract was attributed to ${\alpha}$-tocopherol and BHA.

Effect of pH on the Iron Autoxidation Induced DNA Cleavage

  • Kim, Jong-Moon;Oh, Byul-Nim;Kim, Jin-Heung;Kim, Seog-K.
    • Bulletin of the Korean Chemical Society
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    • v.33 no.4
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    • pp.1290-1296
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    • 2012
  • Fenton reaction and iron autoxidation have been debated for the major process in ROS mediated DNA cleavage. We compared both processes on iron oxidation, DNA cleavage, and cyclic voltammetric experiment at different pHs. Both oxidation reactions were preferred at basic pH condition, unlike DNA cleavage. This indicates that iron oxidation and the following steps probably occur separately. The ROS generated from autoxidation seems to be superoxide radical since sod exerted the best inhibition on DNA cleavage when $H_2O_2$ was absent. In comparison of cyclic voltammograms of $Fe^{2+}$ in NaCl solution and phosphate buffer, DNA addition to phosphate buffer induced significant change in the redox cycle of iron, indicating that iron may bind DNA as a complex with phosphate. Different pulse voltammogram in the presence of ctDNA suggest that iron ions are recyclable at acidic pH, whereas they may form an electrically stable complex with DNA at high pH condition.

Spectroscopic Evidence of the Autoxidation Products Derived from Methyl Linolenate (Methyl Linolenate의 산화생성물(酸化生成物)에 대(對)한 분광학적(分光學的) 연구(硏究))

  • Ahn, Jong-Kyoon;Cho, Mi-Za;Kim, In-Sook;Oh, Sung-Ki
    • Applied Biological Chemistry
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    • v.32 no.1
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    • pp.1-7
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    • 1989
  • The autoxidation products derived from methyl linolenate are isolated and characterized by using thin-layer chromatography, infrared, ultraviolet and nuclear magnetic resonance spectrometries. In addition, the propriety of the application of NMR spectrometry to the analysis of the autoxidation products is examined. Spectroscopic data indicate that the autoxidation of methyl linolenate produces hydroperoxides and trans, cis-substituted diene. The autoxidation products have a predominant cis, trans-conjugated diene system with some trans, trans-configuration. The spectroscopic data of ir, uv, and nmr are very consistent with each other, and further investigation of the multiplet region at $5.83{\sim}6.60ppm$ would be very helpful for the structural elucidation of the autoxidation products.

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Autoxidation Products of Phytofluene in Liposome and Conversion of Phytapentaenal to 4,5-Didehydrogeranyl Geranoic Acid in Pig Liver Homogenate

  • Kim, Seon-Jae
    • Preventive Nutrition and Food Science
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    • v.5 no.4
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    • pp.234-238
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    • 2000
  • The cleavage products formed by autoxidation of phytofluene were evaluated in order to elucidate possible oxidation products of phytofluene under oxidative conditions. Phytofluene solubilized at 50$\mu$M in liposomal suspension was oxidized by incubating at 37$^{\circ}C$ for 72 h. Among a number of oxidation products formed, five products in the carbonyl compound fraction were identified as 6, 10, 14-trimethylpentadeca-3,5,9,13-tetraen-2-one, phytapentaenal, 5,9,13,17-tetramethyloctadeca-2,4,6,8,12,16-hexaenal, 5,9,13,17-tetramethyloctadeca-2,4,8,12,16-pentaenal, 2,7,11,15,19-pentamethylicosa-2,4,6,10,14,18-hexaenal and 4,9,13,17,21-pentamethyldocosa-2,4,6,8,12,16,20-heptaenal. These correspond to a series of products formed by cleavage in the respective eight conjugated double bonds of phytofluene. Also, 4,5-didehydorgeranyl geranoic acid was formed by autoxidation of phytofluene in liposomal suspension. The pig liver homogenate had the ability to convert phytapentaenal to 4,5-didehydrogeranyl geranoic acid, comparable to the conversion of all-trans-retinal to all-trans-retinoic acid. These results suggest that phytofluene is cleaved to a series of long-chain and short-chain carbonyl compounds under the oxidative condition in vitro and that phytapentaenal is further enzymatically converted to 4,5-didehydrogeranyl geranoic acid.

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