METMYOGLOBIN REDUCTION IN BEEF SYSTEMS AS AFFECTED BY AEROBIC, ANAEROBIC AND CARBON MONOXIDE‐CONTAINING ENVIRONMENTS

Abstract

ABSTRACTMetmyoglobin (Mb+) reduction was studied in ground beef, beef slurries and extracts held in air, nitrogen or CO‐air mixtures. Significant Mb+ reduction occurred in aerobic extracts but not in ground beef or slurries in the presence of ferricyanide. A nonenzymatic electron trans. fer was demonstrated in extracts under these conditions. At normal meat pH (5.6), carbon monoxide (CO) accelerated Mb+ reduction, even in the presence of air, with the rate of reduction dependent upon CO concentration. Neither the addition of catalase nor compounds that inhibit the electron transport chain markedly affected Mb+ reduction under a CO atmosphere while arsenate addition slightly accelerated the reaction. The use of ferricyanide as the pigment oxidant increased the Mb+ reduction rate in aerobic extracts and in all systems under CO, but was not necessary to observe reduction under CO. Possible mechanisms for the CO‐enhanced reduction of Mb+ are explored.