Synergism of Ascorbyl Stearate with the Antioxidative Effect of α-Tocopherol

Abstract

The antioxidative effect of ascorbyl stearate (AS) and its synergistic effect with α-tocopherol (α-Toc) in the case of air oxidation of purified trilinolein (TL) and triolein (TO) were examined, and free ascorbic acid (AA) was used for comparison. Samples were oxidized by introducing oxygen at 75°C into a dark glass tube, then oxidized samples were taken at various times and their peroxide values (POV) were measured. The time required for POV to reach 500 (meq/kg) was regarded as the induction period.The following results were obtained.(1) When 0.01-2.0mM/kg of AS was added to TL or TO, and the oxidation test was carried out, no antioxidative effect was observed.(2) TL containing 1.0mM/kg of α-Toc was supplemented with 0.01-2.0mM/kg of AS and subjected to the oxidation test. A synergistic effect of AS was clearly observed; the induction period was prolonged 2.5-3 times compared with α-Toc alone. A similar effect was observed with TO containing 0.1mM/kg of α-Toc, when 0.01-0.3mM/kg of AS was added.(3) An optimum concentration of AS was observed as a synergist with α-Toc; higher levels of As did not increase the effect any further. The effect of AS resembled that of AA.