Physicochemical and biochemical changes during frozen storage of minced flesh of lizardfish (Saurida micropectoralis)

Physicochemical and biochemical changes of minced flesh of lizardfish (Saurida micropectoralis) kept in air and vacuum during frozen storage at −20 °C for 24 weeks were investigated. Formaldehyde and dimethylamine (DMA) contents increased with a concomitant decrease in trimethylamine oxide (TMAO) content as the storage time increased (P<0.05). Ca2+-ATPase activity decreased continuously with a coincidental decrease in the salt-soluble fraction. Disulfide bonds were increasingly formed throughout the storage (P<0.05). Nevertheless, surface hydrophobicity increased and reached a maximum at week 4 with a subsequent decrease up to the end of storage. In general, greater changes were observed in lizardfish mince kept under vacuum than in air. A marked increase in trimethylamine-N-oxide demethylase (TMAOase) activities was observed up to 6 weeks, followed by continuous decrease up to 24 weeks of storage. TMAOase activity, as well as formaldehyde formation, could be reduced to some extent with packaging containing oxygen.