Effect of Freezing on Autoxidation of Oxymyoglobin Solutions^a

Abstract

SUMMARY Rates of oxidation of solutions of highly purified and “crude” tuna and beef oxymyoglobins were measured at 0, −5, −10, −15, and −18°C. The results show that the oxidation rate decreases with lower temperatures until solutions actually solidify; at that time the autoxidation rate increases sharply. There are variations in rates of oxidation between tuna and beef myoglohins, as well as between myoglobin solutions at different buffer concentrations; however, these are secondary to the changes noted due to freezing.

Reverse Stability Kinetics of Meat Pigment Oxidation in Aqueous Extract from Fresh Beef

“…The results of this study agree with those of Brown and Dolev () who found a local minimum for the rate of oxymyoglobin oxidation at −5 °C in aqueous solutions from beef and tuna in phosphate buffer. These authors performed studies on the oxidation of pure tuna and beef oxymyoglobin in phosphate buffer that suggest a maximum at −15 °C ranging from 3 to 150 times the rate in unfrozen solution at −5 °C.…”

“…In fact, Lai found that pure myoglobin in deionized water did not exhibit a rate acceleration under frozen conditions, indicating the cause of this phenomenon is not increased proximity of the myoglobin moieties themselves, but an increased localization of other dissolved species within the system. Brown and Dolev () also observed elevated rates of oxidation for beef myoglobin in phosphate buffer, showing that this effect is apparent with different types of dissolved ionic species.…”

“…One reaction that follows this trend is the oxidation of oxymyoglobin to metmyoglobin, the reaction responsible for the browning of raw and cooked meat. This reaction has been found to have a maximum rate around −15 °C (Brown and Dolev ). Other research suggests the rate maximum is closer to temperatures just below the freezing point (−2 to −3 °C) (Lai ).…”

Effect of packaging and frozen storage temperature on beef pigments

“…Rate constants of Mb02 and MetMb production in frozen systems were reported by Brown & Dolev (1963) and Zachariah & Saterlee (1973) in studies that analysed storage temperature, buffer strength and pH effects on kinetic constants for the autoxidation of Mb02 solutions. Chow et al (1987) analysed the effect of freezing rate on autoxidation of bluefin tuna oxymyoglobin solutions; Lanari et al, (1990) showed the behaviour of muscle pigments in packaged frozen beef.…”

The Influence of Metallic Ions on the Autoxidation of Oxymyoglobin

“…However, all attempts failed to decrease rate constants even further by careful exclusion or removal of metal ions. Yet, for unpurified HbOz and Mb02 (Brown and Dolev, 1963a), rate constants are frequently lower than those for crystallized HbOz or MbOa. The reason for the increased susceptibility to autoxidation upon purification of a heme pigment is not known.…”