Postmortem interactions of muscle temperature, pH and extension on beef quality

Area of Science:

• Meat Science
• Food Science
• Animal Science

Background:

• Beef tenderness is a critical quality attribute influenced by early postmortem muscle conditions.
• Understanding the interplay of temperature, pH, and muscle structure is essential for optimizing beef quality.

Purpose of the Study:

• To investigate the effects of early postmortem temperature, pH, and muscle extension on beef quality, focusing on tenderness.
• To determine how these factors interact to influence key meat quality parameters.

Main Methods:

• A 2x2x2 factorial design was employed using 64 steer carcasses.
• Semitendinosus muscles were subjected to varying temperatures (high/low), pH levels (high/low via electrical stimulation), and muscle lengths (excised/extended) early postmortem.
• Measurements included sarcomere length, fragmentation index, shear force, color, and solubility after 7 days of aging.

Main Results:

• High-temperature aging increased fragmentation and color reflectance while decreasing protein solubility.
• Electrical stimulation (low pH) enhanced sarcomere length only at high temperatures.
• Muscle extension reduced shear force in low-temperature aged muscles and decreased collagen solubility in high-temperature, extended muscles.

Conclusions:

• Postmortem temperature and pH are primary drivers of meat quality.
• Early postmortem muscle extension acts as a significant modulating factor for meat tenderness, especially in conjunction with temperature.
• These findings provide insights for improving beef tenderness through controlled postmortem handling.