Brine‐Curing Process Design for Large Yellow Croaker: An Empirical NaCl Operating Window for Texture Formation and Sodium Reduction

Brine curing is a unit operation in cured seafood manufacturing, and NaCl concentration is a readily adjustable process variable for regulating texture formation, sensory acceptability, and sodium addition. This study evaluated NaCl concentration as a process‐control variable for texture‐oriented brine curing of large yellow croaker ( Larimichthys crocea ). Fish cubes measuring approximately 2 × 2 × 1 cm were cured at 4°C for 6 h in brines containing 0%, 1%, 3%, or 5% NaCl, while sample geometry, curing temperature, curing time, and auxiliary additives were kept constant. Process performance was assessed using product‐level responses, including texture profile analysis, sensory segmentation quality, overall acceptability, and macroscopic appearance; muscle structural responses were used as endpoint indicators to interpret the process behavior. The endpoint responses separated the treatments into three concentration‐dependent regimes. The 0%–1% NaCl treatments represented an under‐processing region, with insufficient network development and poorly defined segmented texture. Approximately, 3% NaCl provided the most favorable empirical operating window, producing the clearest segmented appearance, the highest cohesiveness, and the highest overall acceptability among the tested treatments. In contrast, 5% NaCl crossed an over‐processing threshold, resulting in excessive hardness, reduced juiciness, stronger saltiness, and increased brine NaCl input. Supporting structural measurements indicated that the 3% set‐point corresponded to a controlled intermediate state of cross‐linking, aggregation, and sarcomere‐level reorganization, whereas 5% NaCl showed signs of excessive structural disruption. These findings provide an empirical process‐design basis for texture‐oriented brine curing under the tested conditions and suggest structural responses as candidate endpoint indicators for curing‐process evaluation. Future scale‐up should further quantify salt uptake, diffusion gradients, brine circulation, and geometry–time interactions.