Study of pure and combined antioxidants for replacing TBHQ in soybean oil packed in pet bottles

Oils are subject to several reactions that lead to physical–chemical, sensory and nutritional deterioration. This deterioration process is called rancidity or lipid oxidation, a spontaneous and irreversible phenomenon that can be delayed by the addition of antioxidants. Usually, vegetable oil producers choose to add antioxidants to the upper limit permitted by applicable law as it is not entirely clear the ideal dosages of pure or combined antioxidants designated for this purpose. In order to determine the optimum dosage of antioxidants that minimizes the impact of lipid oxidation of soybean oil bottled in PET (ethylene terephthalate) and replace the traditional antioxidant tert -Butylhydroquinone (TBHQ), an accelerated oven shelf-life test was performed. The antioxidants ascorbyl palmitate (AP), mix of tocopherols and rosemary extract (RE) were evaluated, pure and in combination, at different dosages. Most of the evaluated antioxidants delayed lipid oxidation of soybean oil, but a mixture containing AP and RE presented results of TOTOX statistically lower (higher oxidative stability) than that with TBHQ. One the other hand, regarding OSI at 120 °C, the result obtained by that mixture was statistically lower (less oxidative stability) than that obtained with TBHQ, in both evaluated dosages.