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 ketocarotenoids (astaxanthin and canthaxanthin) stored at 4 degrees C under vacuum-packaging conditions were studied by bacterial enumeration of mesophilic (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 astaxanthin and canthaxanthin concentration occurred. A second decrease in canthaxanthin levels took place at 11 days when a maximun in TEARS values (5.9 +/- 1.7 nmol of TMP/mg of lipid) was also observed. Decrease in carotenoid concentrations was not reflected by color parameters. Evidence indicated that astaxanthin is more stable than canthaxanthin under vacuum packaging at 4 degrees C. On the basis of a TVC limit of acceptability of 10(6) microorganisms/g, the shelf life of rainbow trout fillets, stored under vacuum packaging at 4 degrees C, was 5 days.