Structural changes in collagen and aggrecan during extended aging may improve beef tenderness

Area of Science:

• Meat Science
• Biochemistry
• Food Science

Background:

• Intramuscular connective tissue (IMCT) plays a crucial role in determining meat quality attributes such as tenderness.
• Understanding the structural and property modifications of IMCT during postmortem aging is essential for optimizing meat processing and consumer satisfaction.

Purpose of the Study:

• To characterize the structural and property modifications of IMCT during extended postmortem aging periods.
• To investigate the impact of aging on collagen and proteoglycan components within the IMCT.

Main Methods:

• Longissimus lumborum, Gluteus medius, and Gastrocnemius muscles were collected from USDA choice carcasses.
• Samples were subjected to four aging periods: 3, 21, 42, and 63 days postmortem.
• Tenderness, IMCT texture, collagen transition temperature, collagen chain composition, and aggrecan fragments were analyzed.

Main Results:

• Meat tenderness improved and IMCT texture weakened significantly after 21 days of postmortem aging.
• Collagen transition temperature decreased after 42 days postmortem, indicating structural weakening.
• Alterations in collagen structure (decreased γ chain, increased α1 chain) and a reduction in 75 kDa aggrecan fragments were observed with extended aging.

Conclusions:

• Intramuscular connective tissue (IMCT) weakens during postmortem aging due to significant modifications in its collagen and proteoglycan components.
• These molecular changes in IMCT directly correlate with observed improvements in meat tenderness and texture over extended aging periods.
• The study provides evidence for specific molecular mechanisms driving meat tenderization during aging, offering insights for the meat industry.