The comparative protective effects of gallic acid with well-known synthetic antioxidants (tert-butylhydroquinone, butylated hydroxylanisole, propylgallate) on the thermal oxidations of corn and soybean oils during heating for 8 h at $180^{\circ}C$ wer...
The comparative protective effects of gallic acid with well-known synthetic antioxidants (tert-butylhydroquinone, butylated hydroxylanisole, propylgallate) on the thermal oxidations of corn and soybean oils during heating for 8 h at $180^{\circ}C$ were studied. The quantitative effects of gallic acid at three different concentrations on the time-course thermal oxidations in the two different vegetable oils were also studied for a prolonged heating of 6 days at $180^{\circ}C$. Gallic acid at 200 ppm exhibited higher protective activity than the synthetic antioxidants at the same concentration. Gallic acid also exhibited persistently strong protective activity, in a concentration dependent manner, on the changes in oxidation indices in corn and soybean oils throughout the prolonged heating period (6 days) at $180^{\circ}C$. The present results clearly suggested that gallic acid would be a potential natural substitute of synthetic antioxidants for the protection of vegetable oils during high temperature heating.