title: Lipid oxidation in a chicken muscle model system: oxidative response of lipid classes to iron ascorbate or methemoglobin catalysis.
abstract: Catalysis by iron ascorbate and activated methemoglobin generated different oxidative responses in chicken muscle model systems. In iron ascorbate systems, large increases in hydroperoxides and thiobarbituric acid-reactive substances (TBARS) occurred during the initial stage of incubation. Thereafter, iron ascorbate catalysis led to a slow increase in the oxidation of triacylglcyerol (TG) and sarcoplasmic reticulum (SR) membrane lipids. By the end of incubation, 24, 36, and 32% of the initial content of n-3 fatty acids in free fatty acids, TG, and SR single-lipid model systems catalyzed by iron ascorbate had been lost. Reduced losses of n-3 fatty acids were observed in the SR and TG fractions (0 and 24%, respectively) when iron ascorbate model systems contained all three lipid fractions (mix). Hydroperoxides and TBARS in model systems catalyzed by activated methemoglobin were characterized by a lag phase during most of the incubation. Consistent with their role as antioxidants, losses of alpha-tocopherol (42-49%), gamma-tocopherol (36-42%), and protein sulfhydryls (41-52%) were observed in model systems catalyzed by activated methemoglobin. SR and mix model systems were 30-50% slower to oxidize than TG model systems when activated methemoglobin served as the catalytic agent.
authors.affiliation: Center for Food Safety and Quality Enhancement, Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, Georgia 30223, USA.
authors.forename: R V
authors.initials: RV
authors.lastname: Sista
authors.forename: M C
authors.initials: MC
authors.lastname: Erickson
authors.forename: R L
authors.initials: RL
authors.lastname: Shewfelt
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D002645:Chickens; D007501:Iron / Q000737:chemistry; D050356:Lipid Metabolism; D008706:Methemoglobin / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction
chemical_list: D008706:Methemoglobin; D007501:Iron; D001205:Ascorbic Acid