Bleaching optimization and winterization step evaluation in the refinement of rice bran oil

The aim of this study was to optimize the bleaching step of rice bran oil and to evaluate the winterization step using two cooling conditions and two separation methods (centrifugation and filtration). The use of 1% (w/w) of adsorbent in relation to the mass of oil and 8% (w/w) activated carbon in relation to the total mass of adsorbent were the best conditions of bleaching step, which resulted in a removal of 83% of primary oxidation products and of 57% of carotenoids content. In these bleaching conditions, the oil presented the Totox value of 14.5 ± 2.7 and the chlorophylls content removal was 80%. In the winterization step, the highest separation efficiency (89.1%) was obtained using a cooling rate of 2 °C h−1 (30 °C to 20 °C) and 0.5 °C h−1 (20 °C to 10 °C), and using the centrifugation operation. In these conditions of winterization were found the highest percentages of oleic/linoleic acids and the lowest melting point of the rice oil, showing the increase in unsaturated fatty acids.