Effect of magnetic field-assisted freeze-thaw processing on the protein oxidation and muscle structure of yellowfin tuna.

Abstract

This study investigated the effects of magnetic field-assisted freeze-thaw (FT) processing on the physicochemical properties and muscle structure of yellowfin tuna (Thunnus albacares). Five groups were designed: conventional FT (NMF-FT), alternating magnetic field-assisted FT (AMF-FT), static magnetic field-assisted FT (SMF-FT), AMF-assisted freezing with refrigerated thawing (AMF-FR), and SMF-assisted freezing with refrigerated thawing (SMF-FR). After seven FT cycles, AMF-FT and SMF-FT significantly suppressed protein oxidation, decreasing carbonyl content by 25% and increasing total sulfhydryl by 40% compared with NMF-FT (p < 0.05). Magnetic field treatments promoted the formation of uniform ice crystals, mitigated myofibril disruption, and maintained higher texture hardness. Among all treatments, AMF-FT exhibited the strongest protective effect, followed by SMF-FT, while treatments involving magnetic fields only during freezing showed weaker benefits. Overall, simultaneous magnetic field application during freezing and thawing effectively preserved tuna muscle integrity and protein functionality, providing insights for improving cold chain processing of aquatic products.