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Role of Alpha‐Tocopherol, Ascorbic Acid, Citric Acidand EDTA as Oxidants in Model Systems
Author(s) -
MAHONEY JOHN R.,
GRAF ERNST
Publication year - 1986
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1986.tb13108.x
Subject(s) - chemistry , ascorbic acid , ferrous , citric acid , hydroxyl radical , lipid peroxidation , chelation , peroxide , antioxidant , aqueous solution , hydrogen peroxide , inorganic chemistry , redox , pro oxidant , radical , autoxidation , oxygen , organic chemistry , food science
The effects of four widely employed “antioxidants” on iron‐mediated hydroxyl radical formation and lipid peroxidation were studied in aqueous model systems. Iron and copper served as catalysts for the reactions which oxidized ascorbic acid and alpha‐tocopherol and reduced oxygen. Ferrous ion spontaneously reduced oxygen to O − 2 (su‐peroxide anion radical) which led to OH (hydroxyl radical) and H 2 O 2 generation and lipid peroxidation. Precipitation or sequestration of iron greatly depressed these oxidative events. Complexation by EDTA and citric acid, however, formed catalytically active iron chelates. The concomitant increase in iron solubility explained the substantial enhancement of iron‐driven redox reactions by EDTA and citric acid.