Peroxide dependent and independent lipid peroxidation: Site‐specific mechanisms of initiation by chelated iron and inhibition by α‐tocopherol

Fukuzawa, Kenji; Fujii, Takeru

doi:10.1007/bf02536183

Cited by 51 publications

(33 citation statements)

References 23 publications

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“…M n+1 + O 2 · − + TOH → TO· + HO 2 · + M n+ [18] Moreover, tocopherols and TO· are able to reduce metal ions to lower state valences which will recycle reactions 15-17 (37)(38)(39):…”

Section: Tocopherol Concentration (Ppm) Peroxide Value (Mequiv/kg Oil)mentioning

confidence: 99%

Effects of α‐ and γ‐tocopherols on the autooxidation of purified sunflower triacylglycerols

Fuster

Lampi

Hopia

et al. 1998

Lipids

117

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The antioxidant effects of alpha- and gamma-tocopherols were evaluated in a model system based on the autooxidation of purified sunflower oil (p-SFO) triacylglycerols at 55 degrees C for 7 d. Both tocopherols were found to cause more than 90% reduction in peroxide value when present at concentrations >20 ppm. Alpha-tocopherol was a better antioxidant than gamma-tocopherol at concentrations < or =40 ppm but a worse antioxidant at concentrations >200 ppm. Neither alpha- nor gamma-tocopherol showed a prooxidant effect at concentrations as high as 2000 ppm. The amount of tocopherols consumed during the course of oxidation was positively correlated to the initial concentration of tocopherols, and the correlation was stronger for alpha- than for gamma-tocopherol. This correlation suggested that, besides reactions with peroxyl radicals, destruction of tocopherols may be attributed to unknown side reactions. Addition of FeSO4, as a prooxidant, caused a 12% increase in the peroxide value of p-SFO in the absence of tocopherols. When tocopherols were added together with FeSO4, some increase in peroxide value was observed for samples containing 200, 600 or 1000 ppm of alpha- but not gamma-tocopherol. The addition of FeSO4, however, caused an increase in the amount of alpha- and gamma-tocopherols destroyed and led to stronger positive correlations between the amount of tocopherols destroyed during oxidation and initial concentration of tocopherols. No synergistic or antagonistic interaction was observed when alpha- and gamma-tocopherols were added together to autooxidizing p-SFO.

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Section: Tocopherol Concentration (Ppm) Peroxide Value (Mequiv/kg Oil)mentioning

confidence: 99%

Effects of α‐ and γ‐tocopherols on the autooxidation of purified sunflower triacylglycerols

Fuster

Lampi

Hopia

et al. 1998

Lipids

117

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“…Lipid oxidation was determined using peroxide value (POV, meq kg-1) by the method of Takagi et al (1978). The chelating effect on ferrous ions in the oil emulsion system and the binding effect on ferrous ions in the methanol extracts were measured by the method of Fukuzawa and Fujii (1992).…”

Section: Evaluation Of Antioxidant Activitymentioning

confidence: 99%

Mineral components and anti-oxidant activities of tropical seaweeds

Suzuki

Yoshie-Stark

Santoso

2005

J Ocean Univ. China

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Seaweeds are known to hold substances of high nutritional value; they are the richest resources of minerals important to the biochemical reactions in the human body. Seaweeds also hold non-nutrient compounds like dietary fiber and polyphenols. However, there is not enough information on the mineral compounds of tropical seaweeds. Also we are interested in the antioxidant activities of seaweeds, especially those in the tropical area. In this study, Indonesian green, brown and red algae were used as experimental materials with their mineral components analyzed by using an atomic absorption spectrophotometer. The catechins and flavonoids of these seaweeds were extracted with methanol and analyzed by high performance liquid chromatography (HPLC) ; the anti-oxidant activities of these seaweeds were evaluated in a fish oil emulsion system. The mineral components of tropical seaweeds are dominated by calcium, potassium and sodium, as well as small amounts of copper, iron and zinc. A green alga usually contains epigallocateehin, gallocatechin, epigallocatechin gallate and catechin. However, catechin and its isomers are not found in some green and red algae. In the presence of a ferrous ion catalyst, all the methanol extracts from the seaweeds show significantly lower peroxide values of the emulsion than the control, and that of a green alga shows the strongest anti-oxidant activity. The highest chelation on ferrous ions is also found in the extract of this alga, which is significantly different from the other methanol extracts in both 3 and 24 h incubations.

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“…Yoshida and Niki (1992) and Fukuzawa and Fujii (1992) reported that the iron-catalyzed oxidation of lipids in the micelle system was promoted by the anionic surfactant of so- dium dodecylsulfate and inhibited by the cationic surfactant such as tetradecyltrimethylammonium bromide. Mei et al (1998b) reported that the iron was difficult to bring into lipid, when the interface of the lipid particle and water in emulsion had a positive charge.…”

Section: Resultsmentioning

confidence: 99%

Autoxidation of Fish Oil in Mayonnaise-Like O/W Type Emulsion

Takai

Endo

Okuzaki³

et al. 2003

FSTR

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O/W type emulsions were prepared with salmon oil as lipid and soymilk or whole egg as an emulsifier at different pH, to know the effect of pH on the oxidation and flavor stability of mayonnaise-like emulsions. Emulsions were oxidized in the presence of hemoglobin as a catalyst at 20˚C. Both emulsions prepared with soymilk and whole egg were stable at pH 4 to 6, when the oxidative stability of emulsions was estimated as the induction period. Volatile compounds produced during oxidation were quantified for emulsions at different pH. Total volatiles were highest at pH 4. Propanal was added as a typical volatile compound to emulsions at different pH. The quantity of propanal in the gas phase was highest at pH 4, while it was lowest in the liquid phase at pH 4. The inferior flavor stability of mayonnaise could be due to the high volatility of low molecular weight compounds at pH 4, but this is not true of the oxidative stability.

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Peroxide dependent and independent lipid peroxidation: Site‐specific mechanisms of initiation by chelated iron and inhibition by α‐tocopherol

Cited by 51 publications

References 23 publications

Effects of α‐ and γ‐tocopherols on the autooxidation of purified sunflower triacylglycerols

Effects of α‐ and γ‐tocopherols on the autooxidation of purified sunflower triacylglycerols

Mineral components and anti-oxidant activities of tropical seaweeds

Autoxidation of Fish Oil in Mayonnaise-Like O/W Type Emulsion

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