Effect of light on colour stability of sliced smoked rainbow trout Oncorhynchus mykiss fed astaxanthin

Colour stability of sliced smoked fillets of trout fed astaxanthin exposed to light during chilled storage was monitored by instrumental colour measurements and analyses of flesh astaxanthin content. When exposed to light changes in colour parameters at the surface of sliced smoked rainbow trout fillets occurred. The slices became paler. The level of astaxanthin was not affected by either light or storage conditions. Slices exposed to light had higher TBARS values than those stored in the dark. In our experimental conditions the use of a high initial vacuum level and packaging film with a low oxygen transmission rate maintained the astaxanthin content. However these optimal packaging conditions were not able to prevent significant oxidation of lipids after the initial 2-3 days of display.