Effects of processing and storage on chlorophyll derivatives in commercially extracted canola oil

This study characterizes the chlorophyll pigments present in canola oil immediately after commercial extraction and following oil storage to determine the best storage conditions for analytical samples and to examine the changes that chlorophyll derivatives undergo during oil processing and storage. Samples of pressed, solvent-extracted, crude and degummed canola oils, obtained from a commercial crushing plant, were stored for one month under four different conditions—in the freezer, in a refrigerator and at room temperature both in the light and in the dark. Chlorophyll derivatives (chlorophylls, pheophytins, pyropheophytins) were measured by high-performance liquid chromatography immediately after sampling and then on a weekly basis. The main pigments present in commercially extracted canola oil were pheophytin a, pyropheophytin a, chlorophyll a and chlorophyll b. The “a” derivatives comprised 81 to 100% of total chlorophyll pigments in the fresh oil samples. During degumming, the remaining chlorophylls were converted to pheophytins and pyropheophytins. During oil storage, exposure to light at room temperature affected the composition of chlorophyll derivatives as chlorophyll b was converted to pheophytin b and chlorophyll a was converted first to pheophytin a, then to pyropheophytin a.