Texture and amino acid changes of Chinese mitten crabs (Eriocheir sinensis) and underpinned physiological and metabolic mechanisms during waterless preservation

This study investigated muscle texture and amino acid changes in Chinese mitten crab (<i>Eriocheir sinensis</i>) during waterless preservation and further explored their relationship with physiological and metabolic profiles. During 6-days waterless preservation, significant reductions in muscle integrity, hardness, chewiness, and gumminess were revealed along with gradually decreased vitality. Essential amino acids such as methionine (Met), threonine (Thr) and valine (Val) were selectively preserved despite ongoing protein degradation, suggesting their role in maintaining basal metabolism and flavor attributes. Tissue-specific antioxidant responses were reflected by transient SOD/CAT overactivation and collapse in hepatopancreas, while sustained SOD activity in leg meat mitigated oxidative damage, delaying the deterioration of muscle texture. Day 3 has been suggested as the critical transition point from compensatory energy metabolism to irreversible decompensation, driven by lactate accumulation and antioxidant failure. Collectively, this study provides a scientific basis for quality control in the live crustacean supply chain.