Enriching M. sternomandibularis with -tocopherol by dietary means does not protect against the lipid oxidation caused by high-pressure processing

We hypothesized that elevating the concentration of α -tocopherol in beef muscle tissue by dietary means would increase lipid stability following high-pressure processing. Beef M. sternomandibularis was obtained from cattle that had medium (4.92 μ g/g) and high (7.30 μ g/g) concentrations of α -tocopherol. Post-rigor, paired muscles samples were subjected to pressures of 0.1 (atmospheric), 200 or 800 MPa for 20 min at approximately 60 °C. Following high-pressure processing, measurements were made immediately (d 0) or on samples stored in the dark for 6 d at 4 °C (d 6). Intramuscular lipid was similar for each group (4.02% vs. 4.26%, respectively; P = 0.78), but lipid from the medium α -tocopherol muscle was more saturated and less monounsaturated than muscle from the high α -tocopherol group. High-pressure processing at 800 MPa and 60 °C did not reduce the amount of α -tocopherol but significantly reduced the concentration of linoleic acid (18:2n−6) in muscle from both production groups of cattle. Thiobarbituric acid reactive substances increased linearly with treatment pressure only in d 6 samples (day × pressure interaction P = 0.0001) and were higher overall (P = 0.02) in the high α -tocopherol muscle than in the medium α -tocopherol muscle. At d 6, lipid peroxides were decreased (P = 0.007) by high-pressure treatment and were higher (P < 0.0001) in the high α -tocopherol group than in the medium α -tocopherol group. Therefore, muscle from the high α -tocopherol cattle in this study had a greater accumulation of lipid peroxides by d 6, making the muscle from those cattle more susceptible to oxidation.