The effect of partial-fat substitutions with encapsulated and unencapsulated fish oils on the technological and eating quality of beef burgers over storage

The effects of fat substitution (≤15%) with commercial encapsulated and unencapsulated fish oils on the technological and eating quality of beef burgers over storage [modified atmosphere packs (80% O₂:20% CO₂); constantly illuminated retail display at 4°C; for 15days] were studied using design of experiment (DOE). Burger formulations comprised beef shin (59.5%), salt (0.5%), vitamin E (0.015%) combined with varying levels of beef-fat/fish oils depending on the treatment. Increasing amounts of encapsulated and unencapsulated fish oils in burgers increased polyunsaturated fatty acid content (P<0.001). Storage decreased (P<0.001) a* values, which was in agreement with oxymyoglobin data. Vitamin E inclusion in burgers resulted in higher (P<0.01) oxymyoglobin values. TBARS values increased (P<0.001) over storage as expected. Fat substitution with unencapsulated oils increased cook loss (P<0.001) and decreased hardness (P<0.05) compared to other treatments. Optimisation predicted a burger formulation with 7.8% substitution in beef-fat with encapsulated fish oil. Panellists scored the optimised burger formulation (P<0.05) lower than controls for overall acceptability.