Electroanalysis of meat discoloration: beef sarcoplasm extract with storage time

Electrochemical techniques offer a promising approach for monitoring redox-active biomolecules involved in meat discoloration. Building on our previous identification of characteristic redox peaks in beef extracts associated with myoglobin oxidation (S. B. Kasthuri Dias, S. Bhandari, S. A. Devage, J. A. Avery, R. Kumar, R. Ramanathan and S. Krishnan, <i>J. Am Chem. Soc.</i>, 2024, <b>146</b>, 30728-30732, DOI: 10.1021/jacs.4c09375), we present an extended investigation into electrochemical changes over longer meat storage times. Square wave voltammetry revealed frequency-dependent peak potential shifts over a period of 9 days, indicative of a quasi-reversible electron transfer process. Spiking experiments with purified myoglobin in the meat extract confirmed its predominant contribution to the observed voltammetric signals. After 9 days of storage, peak currents at -0.26 V (redox-active myoglobin heme center) and +0.38 V (overall oxidation of meat components) increased by 68.9% and 270.3%, respectively, compared to relative changes of 37.3% and 61.7% in a shorter-duration study. These electrochemical findings showed a strong correlation with spectrophotometrically determined metmyoglobin accumulation (<i>r</i> = 0.98, <i>P</i> < 0.001). The results provide insight into redox transformations during meat spoilage and contribute to the development of electrochemical tools for evaluating meat quality.