Increasing heat treatment given to canola seed prior to pressing resulted in press oils with progressively increasing contents of non-triglyceride components. Phosphorus and chlorophyll contents ranged from 13 ppm and 7 ppm, respectively, in cold press oil to 64 ppm and 68 ppm, respectively, in oil from heated seeds. Refining reduced the amount of these components to 19 ppm and 60 ppm, respectively, in degummed oil and to 4 ppm and 11 ppm, respectively, in bleached oil. Oil with the lowest amount of non-triglyceride material was obtained by cold pressing and/or bleaching.The major sterols were ~-sitosterol (55%), campesterol (35%) and brassicasterol (10%}, and the major tocopherols were ), (60%), a (30%) and 6 (10%). The content of sterols and tocopherols ranged from 620 to 773 rag/100 g and from 47 to 64 mg/100 g, respectively, in the press oils. The total content of sterols was reduced by 15% and a further 1% on degumming and bleaching, respectively. The total tocopherol content was reduced by 20% and 60% on degumming and on subsequent bleaching. Refining had no effect on the sterol isomer ratio, but there was a significant relative loss of a-tocopherol on bleaching.

Oxidative stability of the canola press oils increased with increasing heat treatment to the seed, and decreased on refining. The tocopherol content of the press oils was relatively uniform and could not account for the observed variations in oxidative stability. The variation in stability corresponded to variations in the content of other non-triglyceride components. In general, the greater the initial quality of the oils, i.e., the lower the content of non-triglyceride material, the lower their oxidative stability. Oxidative stability was found to be significantly correlated to phosphorus content (R2:>0.99). This could be explained by synergism between tocopherols and phospholipids, in the range from 0.025% to 0.22% phospholipid. Above this level increasing the phosholipid content did not significantly improve the oxidative stability. After oxidation the oils were "bleached", i.e., there was a loss of color bodies. This loss was related to both the original content of color bodies in the oil and the degree of oxidation of the oil.