Green seed canola oil is a low-quality green oil. This particular colour is due to the high chlorophyll content that is retained in the mature canola seeds due to exposure to sublethal frost (0-5°C) during seed development (Johnson-Flanagan et al, 1990). Compared to green seed canola oil, pure canola oil has a crystal yellow colour with low chlorophyll content and is produced from canola seeds with low green seed content.

The cost of processing green seed canola oil for edible purposes is high. Oil with high chlorophyll content cannot be used for manufacture of margarine since chlorophyll can inhibit the activity of hydrogenation catalyst (Abraham and de Man, 1986). Also, this oil cannot be used for edible purposes because the high chlorophyll content seriously affects the stability of the oil, causing rapid formation of oxidation products via the photosensitised singlet oxygen pathway (Rawls and Van Santen, 1970). The oxidative degradation of oil produces a number of volatile products that provide a bad odour to the oil. To remove chlorophyll, bleaching can be used; however, this can have a deleterious effect on the stability of a vegetable oil (Tautorus and Low, 1994). Processing conditions used for bleaching could produce new compounds from chlorophyll derivatives in the crude oil. Thus, green seeds are not recommended for feeding purposes. The percentage of green seeds is one of the major gradation factors for canola seeds.

However, tests to produce biodiesel from green seeds oils have been successfully performed. Kulkarni et al. (2006) found that the cloud point of green seed esters is lower than that of pure canola oil esters due to higher content of linoleic and linolenic acids. Furthermore, green seed esters have also been proposed as additive and the use of 1% (v/v) added to ultra-low sulphur diesel fuel to reduce the wear scar area and increase the lubricity has been recommended. Oxidation stability of methyl ester obtained from green seed canola oil is lower (4.9 hours at 110°C) than the European Standard EN 14214. Biodiesel originating from green seed canola oil shows good fuel quality parameters, but its oxidative stability needs to be improved to be considered a viable diesel fuel alternative (Kulkarni et al., 2006).