Expressible juice showed highest increase within the second day of storage. Actomyosin was partially purified from stored muscles. Both reduced viscosity and Mg'+-ATPase activity of actomyosin decreased about 44% in the first day. These changes were due neither to actomyosin dissociation nor fragmentation of major proteins of the complex. Relative percentage of myosin decreased, and actin increased in actomyosin after the second day. These changes are related to a decrease in the myosin heavy chain and could explain the slow decrease in reduced viscosity and Mg*+-ATPase of this protein after the second day.

The characteristics of flounder (Paralichthys patagonicus) were evaluated during a 12‐day period of storage in ice by monitoring the biochemical, microbiological and sensory parameters. The adenosine‐5′‐triphosphate and adenosine‐5′‐diphosphate were not detected, and the initial content of adenosine‐5′‐monophosphate (AMP) rapidly decreased to zero. Inosine‐5′‐monophosphate (IMP) but not adenosine (Ado) was present in muscle extracts. The AMP deaminase activity was found in the muscle. Conversely, the Ado deaminase activity was not detected. A 55% decrease in IMP concentration occurred during the first 2 days of storage. The inosine content was barely detectable (<0.1 μmol/g), probably because of the high nucleoside phosphorylase activity in the muscle. Hypoxanthine significantly (P < 0.01) increased up to the seventh day and then remained approximately constant. The muscle pH fluctuated between 6.6 and 7.0. The iced flounder was microbiologically acceptable for up to 7 days with aerobic plate counts reaching <107 cfu/g. The sensory score, determined by the Quality Index Method, linearly increased (r2 = 0.96) with the keeping time. All the parameters, including the K‐value, indicated that the shelf life of iced flounder was 7 days.

No abstract