The spoilage profile of chilled swimming crab (Ovalipes punctatus): An integrated analysis of physicochemical, flavor compounds, and microbial profiling, highlighting the potential role of Pseudoalteromonas.

Abstract

Crabs are highly susceptible to quality deterioration during chilled storage, primarily due to protein degradation and flavor changes. To systematically evaluate this spoilage process, we stored swimming crab at 4 °C for 5 d and conducted a comprehensive analysis. This included measuring sensory attributes and key physicochemical indices, such as centrifugal loss and trimethylamine (TMA) content, as well as the sulfhydryl content of myofibrillar protein. We also profiled free amino acids (FAAs) and volatile organic compounds (VOCs) and characterized the microbial community composition. The sensory score dropped below the acceptable threshold of 6, centrifugal loss increased by more than 200%, while TMA content exceeded 8 mg/100 g after chilled storage. Additionally, the sulfhydryl content of myofibrillar protein decreased significantly, by 68% in the pincer muscle and 92% in the cephalothorax muscle; the total variable count in both regions increased. Shifts in FAA profiles and an increase in undesirable VOCs were documented. Furthermore, microbial analysis demonstrated that bacterial community succession culminated in dominance by the genus Pseudoalteromonas, which also showed significant positive correlations with VOCs (e.g., 1-octen-3-one and 1-penten-3-one), FAAs (e.g., Met and Tyr), and the deterioration of physicochemical characteristics (e.g., centrifuge loss and TMA content). In conclusion, this integrated study provides a potential scientific foundation for developing targeted strategies to preserve quality and extend shelf life.