Changes in extensibility of raw beef muscle during storage

Area of Science:

• Food Science
• Materials Science
• Biophysics

Background:

• Meat tenderization is a crucial factor in meat quality.
• Understanding the mechanical changes during meat conditioning is essential for optimizing storage and processing.

Purpose of the Study:

• To characterize the mechanical properties of raw meat under tension during storage.
• To identify factors influencing tenderization, specifically irreversible muscle fiber lengthening.

Main Methods:

• Continuous measurement of extensibility and irreversible lengthening in muscle fibers.
• Testing raw meat from 2 hours to 10 days post-stunning.
• Applying cyclic tension between two forces to simulate storage conditions.

Main Results:

• Post-rigor meat exhibited a 40% increase in muscle fiber lengthening and slight extensibility.
• Lengthening occurred earlier at higher post-rigor temperatures and with increased applied stress.
• No lengthening was observed pre-rigor, with a threshold stress of 0.07 Ncm⁻² required for significant lengthening.
• Histological analysis revealed cracks approximately 17 μm apart, suggesting extracellular component involvement.

Conclusions:

• Meat weakening (tenderization) begins at rigor mortis.
• The component responsible for tenderization is significantly weaker than previously estimated.
• Extracellular matrix components likely play a role in the texture changes observed during meat conditioning.