Oxidizability of different vegetables oils evaluated by thermogravimetric analysis

With thermogravimetric analysis (TGA) it is possible to have an estimation of vegetable oil resistance to oxidation, having a measure of weight gain percent (Delta%) due to oxygen caption of oil sample during the oxidation, and of initial and final oxidation temperatures (T-i and T-f). The following samples were examined: extra-virgin olive oil, olive oil, sunflower seed oil, soybean oil, maize oil, peanut oil, rapeseed oil, grape seed oil, hazelnut oil, rice oil and four different kinds of oils for frying. An assessment of data obtained so far makes it possible to point out some interesting outcomes. With regard to weight gain percent, the peanut, rice and extra-virgin olive oils showed the lowest values, whereas the highest one has been detected for one of the oils for frying. As concerns the initial oxidation temperature the rice oil has displayed the maximum value, whereas the same oil for frying above said the minimum. The experimental approach and analytical method developed in this study appear adequate for the purpose, and compared to older techniques offers definite advantages. (C) 2004 Elsevier B.V. All rights reserved.