The Autoxidation of Crystallized Beef Myoglobin a

SUMMARY The autoxidation rate in air for crystallized beef muscle myoglobin and the temperature dependence of the autoxidation were studied. Results show that autoxidation of beef muscle myoglobin is essentially the same as that reported by others for horse heart myoglobin. The rate constant for autoxidation was found to be dependent upon the amount of sodium hydrosulfite used to reduce metmyoglobin. It was shown that increased autoxidation, resulting from relatively high concentrations of sodium hydrosulfite, was not due to hydrogen peroxide. Control of the amount of sodium hydrosulfite used to 0.005% or less substantially reduced fluctuations observed in rate constants for autoxidation. For crystallized beef muscle myoglobin at pH 5.7 and 30°C, the rate constant is 0.21 ± 0.02 hr −1 . The abnormally high temperature dependence of myoglobin autoxidation and the relative importance of bacteria and autoxidation as causes of meat discoloration were discussed.