Interactions between mitochondrial lipid oxidation and oxymyoglobin oxidation and the effects of vitamin E.
Off-flavor and discoloration of meat products result from lipid oxidation and myoglobin (Mb) oxidation, respectively, and these two processes appear to be interrelated. The objective of this study was to investigate their potential interaction in mitochondria and the effects of mitochondrial alpha-tocopherol concentrations on lipid oxidation and metmyoglobin (MetMb) formation in vitro. The addition of ascorbic acid and ferric chloride (AA-Fe(3+)) increased ovine and bovine mitochondrial lipid oxidation when compared with their controls (p < 0.05); MetMb formation also increased with increased lipid oxidation relative to controls (p < 0.05). Reactions containing Mb and mitochondria with greater alpha-tocopherol concentrations demonstrated less lipid oxidation and MetMb formation than mitochondria with lower alpha-tocopherol concentrations. Greater mitochondrial alpha-tocopherol concentration was also correlated with increased mitochondrial oxygen consumption in vitro and with a more pronounced effect at pH 7.2 than at pH 5.6. Relative to controls, succinate addition to bovine mitochondria resulted in increased concentrations of ubiquinol 10 and alpha-tocopherol and decreased lipid and Mb oxidation (p < 0.05). Mitochondrial lipid oxidation was closely related to MetMb formation; both processes were inhibited by alpha-tocopherol in a concentration-dependent manner.
Tang
Jiali
J
Department of Animal Science, University of Connecticut, 3636 Horsebarn Hill Road Ext., Storrs, Connecticut 06269-4040, USA.
Faustman
Cameron
C
Hoagland
Thomas A
TA
Mancini
Richard A
RA
Seyfert
Mark
M
Hunt
Melvin C
MC
D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002417:Cattle; D002712:Chlorides; D005290:Ferric Compounds / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D015227:Lipid Peroxidation / Q000187:drug effects; D008460:Meat / Q000032:analysis; D008929:Mitochondria, Heart / Q000737:chemistry* / Q000378:metabolism; D009211:Myoglobin / Q000737:chemistry*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000187:drug effects; D012756:Sheep; D024502:alpha-Tocopherol / Q000494:pharmacology*
D002712:Chlorides; D005290:Ferric Compounds; D009211:Myoglobin; C017595:oxymyoglobin; D024502:alpha-Tocopherol; D001205:Ascorbic Acid; C024555:ferric chloride