The effect of direct addition of conjugated linoleic acid (CLA) on lipid oxidation was studied. CLA and/or fat trim (4% by weight) were added to the lean trim (96%). Thiobarbituric acid reactive substances (TBARS) were determined on days 0, 3, and 7 for cooked or raw patties stored aerobically at 4C. Addition of CLA during the grinding process increased CLA isomers in both raw and cooked ground beef and decreased TBARS production (P < 0.01). CLA caused a greater reduction in TBARS over storage time in cooked patties than in raw patties (P = 0.006). The concentrations of 18:2n-6 and CLA isomers decreased with storage time. CLA increased 18:2n-6, whereas most fatty acids were decreased by the addition of CLA. CLA did not affect percentages of fat and moisture, cooking loss, or meat color (L*, a*, b*) (P > 0.60).
