Abstract:
The purpose of this study is to identify the intrinsic and extrinsic
quality characteristics of West Coast albacore tuna (Thunnus alalunga). Albacore
tuna were troll caught off the Oregon coast and transferred to the Oregon State
University Seafood laboratory in Astoria, Oregon. Core samples were extracted
from six designated body zones of 16 fish and analyzed for lipid, moisture, protein,
ash, and fatty acid distribution. Proximate distribution was constant throughout the
body zones. Protein and ash made up 25% of the composition, lipid and moisture
made up the remaining 75%. The lipid content ranged from 3.9 ± 0.2 to 36.3 ±
1.1%, with a distribution of higher lipid towards the head and lower lipid towards
the tail. Total omega-3 content averaged 40% of the identified fatty acids for each
body zone, with omega-3 (g/100g tissue) ranging from 2.1 ± 0.5 to 3.5 ± 0.4. Furthermore, an inverse correlation (R²= -0.95) was found for lipid and moisture
content, enabling a faster estimate of lipid content derived from moisture content.
Onboard handling techniques for West Coast albacore tuna were evaluated using
sensory and analytical methods. Chilling (immediately and after 3 h), spiking, and
bleeding at the throat and gills were evaluated by a sensory panel for overall
quality, color, smell, texture and flavor. 2-Thiobarbituric acid-reactive substances
(TEARS) and pH were also compared. Rapid chilling significantly and positively
influenced overall quality, color, texture, and flavor; and significantly reduced
oxidative rancidity. Bleeding at the throat significantly and positively influenced
all sensory attributes tested, but did not significantly influence TEARS or pH.
Neither spiking nor bleeding at the gills significantly affected sensory attributes.
