Influence of pasture or grain-based diets supplemented with vitamin E on antioxidant/oxidative balance of Argentine beef

Thiobarbituric acid reactive substances number and volatile levels of hexanal, pentanal, heptanal, octanal and 3-methylbutanal were higher in grain than in pasture samples (P < 0.05). P + PE meat had higher content of antioxidant vitamins than G + GE samples (P < 0.001). Values ranged from: 15.92 ± 3.48 (G) to 17.39 ± 4.29 (GE) and 25.3 ± 10.0 (P) to 21.98 ± 5.11 (PE) μg/g of ascorbic acid; from 1.05 ± 0.73 (G) to 1.76 ± 0.97 (GE) and 3.08 ± 0.45 to 3.91 ± 0.74 μg/g of α-tocopherol; and from 0.06 ± 0.03 (G) to 0.05 ± 0.01 (GE) and 0.45 ± 0.21 (P) to 0.63 ± 0.27 (PE) μg/g of β-carotene. In addition, principal component analysis clearly separated grain from pasture samples regardless of their supplementation with vitamin E. This level of supplementation did not improve the antioxidant status of fresh meat (P > 0.05). We conclude that pasture diet contributes natural antioxidants in sufficient amounts and is an efficient way to prevent lipid oxidation in fresh beef.