Color Stability of Astaxanthin Pigmented Rainbow Trout Under Various Packaging Conditions

Astaxanthin‐rich oil extract from Louisiana crawfish by‐product imparted a salmon‐red coloration to the flesh and integument of rainbow trout on a diet containing 45 mg astaxanthin/kg feed. Carotenoids deposited in fish flesh were stable (ca 90% retention) in air‐packed samples at 1 ‐ 2°C. Oxygen‐evacuated and CO 2 ‐enriched packaging gave adverse color stability. Lowest pigment levels were in frozen samples, with 53% of the absorbed pigment degraded in 14 days. Visual color scores were consistent with quantitative pigment analyses (r = 0.77). Higher pigment contents were observed in air‐packed (1 ‐ 2°C) samples, possibly due to astacene or other breakdown products of astaxanthin. Maximal TBA values were observed in air‐packed (1 ‐ 2°C) samples. The effect of tissue enzyme homogenate on fading of trout flesh is discussed.