Daily quantification of myoglobin forms on beef longissimus lumborum steaks over 7-days of display using near-infrared diffuse reflectance spectroscopy

Abstract

Oxymyoglobin (OxyMb), deoxymyoglobin (DeoxyMb), andmetmyoglobin (MetMb) content on beef longissimus lumborum muscles weredetermined using a near-infrared (NIR) diffuse reflectance spectroscopy (DRS).  Approximately eighteen wavelengths spanningfrom 480-650 nm were utilized to develop an algorithm to quantify myoglobinforms. Daily changes in subsurface myoglobin redox states were evaluated forseven days using NIR-DRS and compared with surface color assessed by HunterLab MiniScanspectrophotometer. Both measurements revealed that MetMb increased steadilyover the duration of display, showing a high correlation (R2 = 0.91)between the two methods. Comparatively, while NIR-DRS revealed the OxyMb tohave decreased steadily over the period of display, the HunterLab MiniScanspectrophotometer indicated a much later onset of the apparent decrease ofOxyMb than NIR-DRS reading, resulting in a moderate correlation (R2= 0.64) between the two methods. No correlation was found between the twomethods regarding the changes of DeoxyMb over the duration of display. NIR rayscan penetrate deeper into the muscle sub-surface than visible light and probemyoglobin forms. The newly developed NIR-DRS algorithm has potential as analternative method for the color assessment in post-rigor skeletal muscle.