837Chlorophyll derivatives in canola oil were analyzed quantitatively by reversed-phase high-performance liquid chromatography without any pretreatment. The main components were pheophytin (pheo) a and b and pyropheophytin {pyro} a and b. The factors affecting the types and concentration of chlorophyll derivatives in oil have been investigated during seed preparation, expelling, extraction, degumming and alkali-refining processes. Bleaching tests of alkali-refined canola oil with activated earth indicated the adsorption of each derivative to decrease in the following order: pheo a > pyro a >> pheo b > pyro b. In bleaching with activated carbon, however, the following order was observed: pyro b > pheo b > pheo a > pyro a.KEY WORDS: Adsorption isotherms, bleaching, canola oil, chlorophyll derivatives, pheophytin a, pheophytin b, pyropheophytin a, pyropheophytin b, refining process, seed preparation.