Electrochemical Measurement of Freeze-Thaw Cycle Impact on Sarcoplasmic Oxidation in Beef

Repeated freezing and thawing (F-T) of meat, a common practice in home kitchens, markets, and transportation, reduces meat quality due to wide temperature fluctuations. This study presents the electrochemical analysis of oxidation in beef longissimus lumborum muscle sarcoplasm under repeated F-T cycles, which differs from prior reports that focused on other related meat aspects, such as discoloration, adulteration, freshness, and antibiotic detection. Moreover, comparing the complexity of meat extract analysis using certain spectral methods, such as Raman, NMR, FTIR, and expensive mass spectrometry, electrochemical methods offer simplicity, speed, and cost-effectiveness. Increased current responses at specific peaks (0.82 ± 0.01 V and -0.25 ± 0.01 V vs Ag/AgCl) correlated strongly (<i>r</i> = 0.99, <i>p</i> < 0.01) with elevated metmyoglobin content, which is responsible for the discoloration or brown color of meat, validated by spectrophotometry. Frozen sarcoplasm (day 3) exhibited significantly higher currents and metmyoglobin levels (<i>p</i> < 0.01) compared to fresh sarcoplasm (day 0), indicating biochemical changes during F-T cycles. Electrocatalytically accessed redox signals of purified beef myoglobin confirmed the contributions from the rapid oxidation of myoglobin, as well as other meat sarcoplasmic proteins. This research introduces a portable, cost-effective electrochemical tool for point-of-need monitoring of meat oxidation under various practical, experimental, and environmental conditions. Future research could focus on obtaining insights into biochemical changes in longissimus lumborum sarcoplasm during frozen storage and developing strategies to mitigate the effects of F-T cycles on meat quality.