Abilities of some antioxidants to stabilize soybean oil in industrial use conditions

Antioxidants, chelators, and alcohols were screened at 0.01 and 1.28% by weight for their ability to delay viscosity increase in soybean oil in the presence of metallic colloidal copper and iron at 105 C with air flowing through the sample. Most substances did not significantly enhance the effect of the natural tocopherols in the soybean oil at 0.01%. A few substances were mildly prooxidant, and a few delayed the increase in viscosity significantly. TBHQ at 0.01% was the best antioxidant of those: tested. At 1.28% ascorbyl palmitate, BHT, hydroquinone, and TBHQ increased the stability significantly. Again, TBHQ was the most effective. As measured by viscosity increase to 150 CP, TBHQ increased stability about five times over that of soybean oil controls.