ABSTRACT
In recent years vacuum frying was developed as an alternative methodology to traditional frying. In this study, sunflower oil thermoxidation was evaluated using conventional process conditions (180 °C and atmospheric pressure) and vacuum technology conditions (130 °C and 0,1 bar). Traditional thermoxidation lasted 20 h while vaccum thermoxidation was completed after 56 h. Total polar compounds reached 23 and 7,1 % at the end of atmospheric and vacuum thermoxidation respectively, while polymers content was 9,3 and 2,2 % for each oil. Tocopherols contents decreased 45 % for atmospheric thermoxidized oil and were reduced to 17 % for vacuum thermoxidized oil. These results clearly proved vacuum thermoxidation achieved a significantly lower deterioration rate than atmospheric thermoxidation of sunflower oil, conferring it much longer useful life and better nutritional qualities. Accordingly, a singnificantly slower vanishing rate of tocopherols was observed in vacuum thermoxidation.
