RESUMO
The effects of dietary modification with flaxseed oil-enhanced (Flax) feed on the product quality of brook trout fillets were examined. Trout were fed a commercial feed supplemented with fish oil (CD) or flaxseed oil (Flax) for 165 d before harvesting. Proximate composition and fatty acid profile were determined on fillets. Quality parameters of the raw fillets were examined over the storage period by measuring color (L*, a*, b*), muscle pH, and thiobarbituric acid reactive substances test. Evaluations on the cooked fillets included sensory evaluation with triangle tests and a paired preference test. There were no differences in proximate composition between the groups; however, the total omega-3 fatty acids were greater in Flax fillets (P<0.05). Diet and day were shown to interact in their effect on whiteness, pH, and lipid oxidation (P<0.05); however, linear regression did not determine that malondialdehyde concentration was associated with time in either diet type implying that lipid oxidation in the vacuum-packed fish was controlled at storage temperatures (4°C). Sensory panelists were able to choose the odd sample in a replicated triangle test analyzed using the ß-binomial model, and there was preference for Flax fillets (P<0.05). Results indicate that a Flax-enhanced diet would have favorable effects on product quality of farmed brook trout.
