Comparative study of air-blast and cell-alive system (CAS) freezing on the quality of thawed masu salmon (Oncorhynchus masou) sashimi

This study evaluated the effects of the novel cell-alive system (CAS) freezing method compared to conventional air-blast freezing on the quality of thawed masu salmon (Oncorhynchus masou) sashimi. Physicochemical changes (ATP-related compounds, K-value, free amino acids, pH, color changes, and microstructure) were monitored. Both methods showed similar results in ATP and IMP degradation after thawing. After 48 hours of post-thawing storage, the K-value remained below the 20 % threshold for both methods, indicating good quality. Anserine was abundant in masu salmon muscle, with sixteen FAAs detected, including flavor-contributing FAAs such as Glu, Gly, Ala, and His. pH slightly decreased after thawing but was similar for both methods. The taste-active value (TAV) for sweetness increased due to glycine, while umami taste also became more intense, as indicated by equivalent umami concentration (EUC) values of 7.01 g MSG/100 g (CAS) and 6.90 g MSG/100 g (Blast) after 48 hours. Colorimetric results revealed a transient decline in lightness (L*) after thawing followed by a recovery. No significant difference in ice crystal size was observed between the two freezing treatments. Overall, both methods effectively preserved the flavor and quality attributes of thawed sashimi, with no significant differences between them.