Enhancing oxidative stability and quality of frozen fish during storage: A hydrogen-fumigation coupled with chitosan-ice glazing assisted freezing approach.

Lipid and protein oxidation during frozen storage remain a primary bottleneck for fish preservation. An innovative freezing strategy integrating hydrogen-fumigation and chitosan-ice glazing (HAC) was developed to provide enhanced oxidative protection and improved quality for frozen fish. Results indicated that HAC best maintained the freshness of tilapia fillets after 37 days of frozen storage, exhibiting lower lipid/protein oxidation and superior quality properties (31.32 mJ chewiness, 59.36 whiteness, and 93.64% immobile water) compared to individual treatments. Microscopy indicated that HAC better preserved muscle integrity while establishing finer chitosan-mediated nanoscale domains around myofibrillar proteins (MPs), suggesting a potential nanoconfined antioxidant microenvironment. Moreover, superior MP conformational stability (21.37% α-helix, 22.29% β-sheet, and 38.58% random coil) and significantly mitigated oxidative damage (6.34 and 112.97 nmol/mg protein for carbonyls and sulfhydryls, respectively) were achieved in the HAC group. This work provides a novel approach for preserving the oxidative stability and quality of frozen aquatic products.