Postmortem changes of sardine muscle during 15 d storage at 0 °C were studied to evaluate its quality and functionality. No microbial deterioration was detected since trimethylamine and histamine concentration remained low with final values of Յ 1.62 mg/100g and 0.00018 ppm, respectively. A final proteolytic activity Յ 20 g Tyrosine/min/g protein was detected. Lipid oxidation from moderate to advanced was detected after day 5 with values of 31.8 to 33.9 meq/kg and 26 mg/kg for peroxide value and thiobarbituric acid value respectively. Muscle protein showed no gel-forming ability. Extraction of myofibrillar protein decreased 45% and 81% at day 5 and 15 respectively. Overall results indicated that good quality was maintained during the storage period with a final K value of 50.7% when proper handling practices were implemented.

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Quality characteristics of black-skipjack (Euthynnus lineatus) muscle kept in ice were evaluated by monitoring changes in chemical, microbiological, and sensory parameters over a 24-d storage period. The K value increased linearly (r 2 = 0.966) from < 20% before d 3 to 75% at d 18. Muscle pH fluctuated between 5.7 to 6.0. Histamine did not exceed 50 ppm, while putrescine and cadaverine were < 40 ppm. Lipid deterioration was rather low with TBA values of 5 mg/100g at d 18. Descriptive sensorial evaluation indicated excellent-to-good attributes at d 6 and good-to-acceptable at d 18. Sensory assessment and K value gave the highest correlation with storage time, indicating a shelf life of 18 d.

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Several freshness and spoilage indicators were monitored to characterize the postmortem biochemistry of giant squid (Dosidicus gigas) mantle muscle. Squid samples were obtained directly from the sea and kept at 0 degrees C during a 15-d storage period. Data at zero time were obtained from cryogenically frozen samples at time of capture. The adenosine 5'-triphosphate (ATP) degradation followed a different pattern as compared with that from fish species. ATP was almost completely depleted at 24-h postcatch from 6.54 to <1 micromol/g, while at the same time Hx was the predominant catabolite with a concentration of 4 mumol/g, reaching 6.85 micromol/g at day 15. K-value data followed a logarithmic pattern with time instead of a linear one, with no change after day 3, thus reducing its suitability as a freshness index. The coefficient Hx/AMP seems to be an adequate alternative for this purpose due to its constant increment with time. The high NH4Cl content in mantle muscle (461.3 +/- 24.5 mg of NH4(+)/100 g) derived from its physiological importance for the species compromises the use of the distillation step of the TVB-N analysis commonly used as a spoilage index. This fact explains why the initially high value of TVB-N detected in mantle muscle (243.7 mg N/100 g) did not correlate with the initial low TMA-N content (1.5 +/- 0.1 mg/100 g of muscle). The results suggested that under the experimental conditions the shelf life of squid exceeds 15 d.