Use of alpha-tocopherol combined with synergists and compared to other antioxidants on the oxidative stability of sardine skin lipids

Antioxidant effectiveness of alpha-tocopherol (Toc) was determined in concentrations 0.01%, 0.1%, 1% and 10% combined with the synergist action of lecithin (Lec) and ascorbic acid (AA). Evaluations were carried out in a model system of lipids extracted from sardine (Sardinops melanoxticta) skin. The course of the oxidation was evaluated measuring the oxygen uptake (mmol of O2/kg lipids), samples were incubated in closed cylinders at 40°C in darkness. The most effective combination observed was 0.01% Toc+0.5% Lec+0.05% AA. This treatment prolonged during 14 days the stage of the oxidation initiation. Higher concentrations of Toc promoted oxidation. The addition of 5% Lec although more effective for antioxidative purposes, affected drastically the color of the samples. Application of 0.01% Toc without synergists could only stop the oxidation for 4 days when compared with other commercial anti-oxidants (sodium erythorbate, BHA and TBHQ). This suggests that the combination of these antioxidants with synergists could be efficient.