QUALITY OF PIGMENTED (ASTAXANTHIN AND CANTHAXANTHIN) RAINBOW-TROUT (ONCORHYNCHUS-MYKISS) FILLETS STORED UNDER VACUUM PACKAGING DURING CHILLED STORAGE

Shelf life and color stability of muscle of rainbow trout fed ketocaro tenoids (astaxanthin and canthaxanthin) stored at 4 degrees C under va cuum-packaging conditions were studied by bacterial enumeration of mes ophilic (TVC), psychrotrophic (TPC), and total coliforms (TC), TEARS ( 2-thiobarbituric acid reactive substances), color measurements (CIELCH ), and carotenoid quantification by HPLC. An increase of TEARS values and microbial development was observed at 5 days when a loss in astaxa nthin and canthaxanthin concentration occurred. A second decrease in c anthaxanthin levels took place at 11 days when a maximun in TEARS valu es (5.9 +/- 1.7 nmol of TMP/mg of lipid) was also observed. Decrease i n carotenoid concentrations was not reflected by color parameters. Evi dence indicated that astaxanthin is more stable than canthaxanthin und er vacuum packaging at 4 degrees C. On the basis of a TVC limit of acc eptability of 10(6) microorganisms/g, the shelf life of rainbow trout fillets, stored under vacuum packaging at 4 degrees C, was 5 days.