EFFECTS OF DIFFERENT ANTIOXIDANTS ON OXIDATIVE STABILITY OF SOYBEAN OIL IN PET BOTTLES EFEITOS DE DIFERENTES ANTIOXIDANTES NA ESTABILIDADE OXIDATIVA DO ÓLEO DE SOJA EM GARRAFAS PET

Abstract

Lipid oxidation is responsible for physicochemical and organoleptic changes which reduce not only the food shelf life but also its acceptability. However, this deterioration process can be delayed or prevented by the addition of antioxidants. The aim of this study was to evaluate the effect of different antioxidants, pure and in combination (ascorbyl palmitate, rosemary extract and mix of tocopherols) compared to TBHQ ( tert -butylhydroquinone) on oxidative stability index (OSI) of soybean oil stored in PET bottles by Rancimat at 120°C. The rancimat method is included in the AOCS Cd 12b-92 standard, due to the ease of use and reproducibility that allows the OSI evaluation in a relatively short period. Therefore, an accelerated shelf life study was performed at 60°C for 30 days. The results showed that all evaluated antioxidants and their combinations delayed the lipid oxidation of soybean oil.  However, a mix containing ascorbyl palmitate and rosemary extract presented OSI (Oxidative Stability Index) similar to TBHQ. At the end of the 30th day, this referred blend of antioxidants had OSI of 4.83 hours at 120 °C, while treatment with TBHQ showed 5.90 hours at the same temperature. Thus, it was concluded that the evaluated concentration of the ascorbyl palmitate and rosemary extract blend may be an excellent alternative to TBHQ during the maintenance of the soybean oil shelf life in PET bottles.