Iridescence in beef caused by multilayer interference from sarcomere discs

Area of Science:

• Food science
• Biophysics
• Meat science

Background:

• Iridescence in beef is an uncommon phenomenon.
• The origin of interference colors in meat has not been definitively established.
• Sarcomere structures are fundamental components of muscle tissue.

Purpose of the Study:

• To investigate the hypothesis that interference colors in beef originate from reflections off sarcomere discs.
• To analyze the optical properties of meat exhibiting iridescence.
• To determine the relationship between sarcomere structure and light scattering in beef.

Main Methods:

• Microscope photometry was employed on raw and cooked iliocostalis muscle samples.
• Polarization techniques were used to analyze light pathways and interference.
• Reflectance spectra were measured to identify interference peaks.

Main Results:

• Interference colors persisted regardless of polarizer rotation in single pathways but were extinguished when polarizers were crossed.
• Reflectance spectra revealed multiple interference peaks, suggesting layered origins, likely from sarcomeres.
• The intensity of major interference peaks showed a strong dependence on the angle of measurement.

Conclusions:

• Reflections from sarcomere discs are a plausible source of interference colors in beef.
• Sarcomere discs may represent a widespread mechanism for light scattering in meat.
• Understanding these optical properties can enhance knowledge of meat quality and appearance.