PHASE-TRANSITIONS OF CANOLA OIL SEDIMENT

Canola sediment was obtained from an industrial filter cake by solvent extraction. When heated in the differential scanning calorimeter (DSC ) (5-100-degrees-C), the sediment exhibited a single narrow melting pe ak at around 74.8-degrees-C. No solid-state polymorphic transformation of the material could be detected over this temperature range. The X- ray powder diffraction pattern of canola sediment resembled waxes from other sources with an orthorhombic unit cell. The phase transition be havior of canola sediment in oil was studied by both DSC and polarizin g microscopy. With increasing ratio of oil/sediment, a reduction in bo th melting temperature and transition enthalpy was observed. The shape of the supercooling curve resembled that of the melting curve. The in duction time was determined by spectrophotometry and was used to calcu late the interfacial free energy sigma between sediment and oil; sigma = 4.71 erg/cm2. The effect of temperature and sediment concentration on the clouding time of canola oil was studied; the clouding time was the shortest at 5-degrees-C.