Evolution of tissue microstructure, protein properties, and oxidative stability of salted bigeye tuna (Thunnus obesus) meat during frozen storage

Abstract

The characteristics of ice crystals, tissue recoverability, protein properties, and lipid oxidation were investigated to reveal the effects of salting time (0–8 h) on the frozen storage stability of tuna meat. After 2 w of frozen storage, the ice crystals in tuna meat with different salting time varied in morphological properties, evolving from large columns (0 h) to ellipsoid (0.5–3 h) and plate shape (5–8 h). The ice crystals in tuna meat with salting time of 1–3 h were more stable with the extension of frozen storage. The enhanced water-holding capacity, springiness, and cohesiveness were attributed to the modified morphology and stability of ice crystals and tissue recoverability after thawing with the formation of moderate protein-protein interactions under proper salting conditions. The declined oxidative stability of salted tuna meat was likely associated with the loss of redox balance with the extension of salting as indicated by aggravated oxidation of lipid and myoglobin and discoloration. Salting time must be taken into account for the frozen storage stability of salted aquatic products, which could modify the microstructure of both frozen and thawed meat, protein properties, redox status of tissue, and thus quality attributes.