title: Characteristics of egg yolk phosvitin as an antioxidant for inhibiting metal-catalyzed phospholipid oxidations.
abstract: A study was conducted to determine the antioxidant activity of phosvitin in an egg yolk phospholipid emulsion system. Various inorganic and organic metals (Fe2+, Cu2+, and hemin) in several different concentrations were added individually to the emulsions to induce lipid oxidation. Characteristics of phosvitin for inhibiting these metal-catalyzed lipid oxidations were investigated. The effect of heat treatments, both pasteurization (61.1 C, 4 min) and autoclaving (121.1 C, 10 min), on phosvitin was examined to find out if there was any effect on its antioxidant characteristics. Lipid oxidations were measured by thiobarbituric acid assays. Phosvitin effectively inhibited Fe2+ and Cu2+-catalyzed phospholipid oxidations as shown by low malondialdehyde values over the entire reaction period; however, it did not exert similar effects on the hemin-catalyzed oxidation reaction. Phosvitin demonstrated higher capacity to inhibit iron catalysis of phospholipid oxidations (up to 30:1 Fe2+-to-phosvitin molar ratio) than copper catalysis (1:1 molar ratio). Pasteurization did not change the antioxidant activities of phosvitin; however, autoclaving decreased phosvitin's inhibitory capacity on iron catalysis.
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D002384:Catalysis; D003300:Copper; D004527:Egg Proteins / Q000494:pharmacology*; D004530:Egg Yolk; D066298:In Vitro Techniques; D007501:Iron; D010084:Oxidation-Reduction; D010743:Phospholipids / Q000378:metabolism*; D010774:Phosvitin / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D004527:Egg Proteins; D010743:Phospholipids; D003300:Copper; D010774:Phosvitin; D007501:Iron