Effects of α-tocopherol, β-carotene and ascorbyl palmitate on oxidative stability of butter oil triacylglycerols

Butter oil triacylglycerols (BO-TAGs), free of antioxidants, including beta-carotene, were obtained via sequential treatments with activated carbon (AC) adsorption and alumina column chromatography. cc-Tocopherol, beta-carotene and ascorbyl palmitate (AP) were added to BO-TAGs, individually, or in different combinations. An accelerated oven-oxidation test was carried out at 60 degrees C to determine the most effective dosages of the antioxidants. Among the antioxidants evaluated, alpha-tocopherol was found to be the most effective, at the concentration of 50 mu g/g. To determine the possible synergism between the antioxidants, binary or ternary combinations of alpha-tocopherol, beta-carotene and AP were added to BO-TAGs at concentrations of 50, 5, and 50 mu g/g, respectively. Ternary combinations of these antioxidants were significantly better in retarding oxidation than were binary blends of alpha-tocopherol with beta-carotene or AP. However, a prooxidant effect was observed, especially when beta-carotene and AP were used individually or in binary combination. (C) 2010 Elsevier Ltd. All rights reserved.