Evolution of quality characteristics and bacterial community in vacuum-packed soft-shell mud crab during slurry ice...

Slurry ice is known to extend the shelf life of refrigerated seafood, yet its specific impact on the quality and microbiota of soft-shell mud crabs during storage has not been well characterized. This study examined changes in the K-value, xanthine oxidase (XOD) activity, free amino acids, flavor nucleotides, and bacterial community succession in the muscle of vacuum-packed soft-shell crabs during slurry ice cooling and cold storage. The results showed that the crabs retained acceptable biochemical freshness (K-value < 40%) for up to 7 days. XOD activity increased over time. Gly, _L-Arg, _L-Ala, and _L-Glu were identified as the predominant FAAs, and their marked reduction significantly influenced flavor development. Adenosine monophosphate was the most abundant flavor nucleotide, followed by inosine monophosphate; the decline in both compounds contributed to a reduction in the equivalent umami concentration. Furthermore, while the α-diversity of the muscle bacterial community remained stable, an increase was observed in four families-primarily Comamonadaceae and Shewanellaceae. Notably, the rise in amplicon sequence variant 936 (ASV936, assigned to Shewanella) by day 7 suggested the onset of spoilage. These findings demonstrate that slurry ice cooling combined with cold storage can effectively maintain the edible quality of soft-shell crabs for 7 days, offering a viable method for short-term preservation.