title: Enriching M. sternomandibularis with alpha-tocopherol by dietary means does not protect against the lipid oxidation caused by high-pressure processing.
abstract: We hypothesized that elevating the concentration of alpha-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 microg/g) and high (7.30 microg/g) concentrations of alpha-tocopherol. Post-rigor, paired muscles samples were subjected to pressures of 0.1 (atmospheric), 200 or 800 MPa for 20 min at approximately 60 degrees C. Following high-pressure processing, measurements were made immediately (d 0) or on samples stored in the dark for 6 d at 4 degrees C (d 6). Intramuscular lipid was similar for each group (4.02% vs. 4.26%, respectively; P=0.78), but lipid from the medium alpha-tocopherol muscle was more saturated and less monounsaturated than muscle from the high alpha-tocopherol group. High-pressure processing at 800 MPa and 60 degrees C did not reduce the amount of alpha-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 x pressure interaction P=0.0001) and were higher overall (P=0.02) in the high alpha-tocopherol muscle than in the medium alpha-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 alpha-tocopherol group than in the medium alpha-tocopherol group. Therefore, muscle from the high alpha-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.
authors.affiliation: CSIRO, Food and Nutritional Sciences, Cannon Hill, Queensland, Australia. ron.tume@csiro.au
authors.forename: R K
authors.initials: RK
authors.lastname: Tume
authors.forename: A L
authors.initials: AL
authors.lastname: Sikes
authors.forename: S B
authors.initials: SB
authors.lastname: Smith
mesh_terms: D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D002417:Cattle; D004032:Diet; D004041:Dietary Fats / Q000032:analysis / Q000302:isolation & purification; D005227:Fatty Acids / Q000032:analysis / Q000302:isolation & purification; D006358:Hot Temperature; D019787:Linoleic Acid / Q000032:analysis / Q000302:isolation & purification; D015227:Lipid Peroxidation; D008054:Lipid Peroxides / Q000032:analysis; D008460:Meat / Q000032:analysis*; D008462:Meat-Packing Industry / Q000379:methods*; D011312:Pressure / Q000009:adverse effects*; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D013997:Time Factors; D024502:alpha-Tocopherol / Q000008:administration & dosage* / Q000032:analysis*
chemical_list: D004041:Dietary Fats; D005227:Fatty Acids; D008054:Lipid Peroxides; D017392:Thiobarbituric Acid Reactive Substances; D019787:Linoleic Acid; D024502:alpha-Tocopherol