Effects of ultra-high pressure combined with egg white protein on the sodium release and flavour of reduced‑sodium surimi products.

Salt reduction in shrimp surimi is constrained by weakened gel networks, inefficient sodium release, and loss of characteristic flavour. This study evaluated whether ultra-high-pressure treatment (UHP, 290 MPa, 15 min) combined with egg white protein (EWP) could improve saltiness perception and flavour release in Litopenaeus vannamei surimi containing 1.5% NaCl. Five treatments were compared: reduced-salt control, normal-salt control, UHP alone, EWP alone, and UHP-EWP co-treatment. Electronic tongue and sensory analyses showed that UHP-EWP produced the strongest saltiness response among the reduced-salt samples and achieved taste, texture, and overall acceptability close to the 2.5% NaCl control. Conductivity monitoring and ICP-OES confirmed that the co-treated gel promoted Na+ release during simulated oral processing, particularly at later mastication stages. SEM-EDS mapping further showed a more homogeneous sodium distribution after UHP-EWP treatment, whereas EWP alone caused localized sodium enrichment and delayed release. HS-SPME-GC-MS, electronic nose, and GC-IMS analyses indicated treatment-dependent remodeling of the volatile profile and clear separation between treated and control samples. These results suggest that UHP-induced protein unfolding and EWP-assisted co-gelation reconstructed the surimi matrix, thereby coordinating sodium mobility, ion spatial distribution, and volatile release. The UHP-EWP strategy offers a promising clean-label route for developing reduced‑sodium marine gel foods, although molecular-level verification, consumer validation, and pilot-scale cost assessment are still needed.