7 The lowest content of tocopherols was found in cold pressed canola oil. When temperature of pressing was increased,  the amount of tocopherols doubled (Figure 9). Solvent extracted oils contain higher amounts of toco- pherols than cold pressed oil,  and similar amounts as oils from hot press- ing. Refining decreased the tocopherol content of canola oil,  and deodor- ization caused the removal of the largest portion of these compounds. Sterols Sterols are present in canola oil in equal amounts in two forms,  free and esterified (Ackman,  1983; Evershed et al.,  1987).  The composition of fatty acids and sterols in the esterified sterol fraction of canola oil is pre- sented in Figure 10. Two of the major sterols (campesterol and sitosterol) are equally distrib- uted in the esterified and free sterol fractions in canola oil (Figure 11B). Twice the amount of brassicasterol is found in the free sterols than in the esterified. The fatty acid distribution in the esterified sterol fraction differs from the fatty acid distribution of canola oil (Figure 11A). A higher palmitic and stearic acid content was observed in the esterified sterols. The total amount of sterols in rapeseed and canola oils ranges from 0.53 to 0.97%.  The composition of major sterols in common vegetable oils is presented in Table 12,  and their structures are presented in Figure 12. Brassicasterol is one of the major sterols present in rapeseed and canola, and is also unique to these oils. This sterol is often used to determine the presence of rapeseed or canola oils in other oils (Strocchi,  1987; Ackman, 1990).  Sterols are also affected by processing. Significant portions (up to 40%) of sterols are removed from the oil during deodorization. Refining also causes removal and isomerization of these compounds (Kochar, 1983; Marchio et al.,  1987). The amount of total sterols in canola oil is about 50% higher than in soy- bean oil. Corn oil,  which is produced from the corn seed embryo,  con- tains the highest amount of sterols,  or roughly two times that found in canola oil.  The chemical structure of phytosterols is similar to that of cholesterol,  so it is possible that these compounds are involved in oxida- Free Sterols Esterified Sterols