Dynamic remodeling of intramuscular structural proteins and its impact on abalone muscle quality during post-mortem...

Post-mortem abalone muscle undergoes significant textural changes during cold storage, characterized by a rapid (0-3 days) and slow (3-7 days) softening period, with hardness decreasing by 65% (P < 0.05) and 76% (P < 0.05), respectively. To investigate the underlying mechanisms of abalone muscle softening during cold storage, dynamic changes in muscle quality, tissue structure, and protein composition were studied. This study revealed that texture deterioration was primarily driven by progressive degradation of intramuscular connective tissue (IMCT) and muscle fibers (MF). Microstructural analyses demonstrated that IMCT degradation preceded MF disruption, with collagen hierarchical structure becoming increasingly disorganized during storage. During rapid softening period, IMCT experienced substantial collagen degradation, resulting in a reduction of collagen content to 1.12%, while MF primarily underwent denaturation with minimal protein degradation. The slow softening period was marked by continuous collagen reduction and significant myofibrillar protein (MP) degradation, particularly affecting paramyosin (P < 0.05). These findings established that phased textural changes in post-mortem abalone muscle resulted from sequential IMCT structural damage, MF integrity loss, and MP denaturation/degradation, providing insights for optimizing abalone processing and preservation techniques.