EFFECTS OF CRYSTALLIZATION CONDITIONS ON SEDIMENTATION IN CANOLA OIL

The effects of various factors on sediment formation in canola oil were studied. The crystallization temperature of sediment varied with cooling rate, whereas the melting temperature depended on heating rate as well as the cooling rate during sediment formation. The final crystal size depended on cooling rate. The crystal habit of sediment was generally rod-like but could change to a round and leaflike shape at low cooling rates (<0.5 degrees C/min). Crystal nude ation occurred in the initial stage of crystallization, while crystal growth was observed during the whole crystallization process, decreasing as cooling proceeded. Crystal growth rate of the sediment was proportional to the crystal surface area. Lecithin did not affect the phase transition temperatures of sediment, but retarded crystal growth.